33 CFR 118.60 - Characteristics of lights.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Characteristics of lights. 118.60... LIGHTING AND OTHER SIGNALS § 118.60 Characteristics of lights. All lights required or authorized under this.... Lights must meet the requirements of this part. Lights shall be fixed lights excepting as provided in...

Green light in photomorphogenic development

NASA Astrophysics Data System (ADS)

Maruhnich, Stefanie Anne

Light quality, quantity, and duration provide essential environmental cues that shape plant growth and development. Over the last century, researchers have worked to discover how plants sense, integrate, and respond to red, blue, and far-red light. Green light is often considered a “benign” wavelength with little to no effect in plant development. However, sparse experiments in the literature demonstrate that green effects are often counterintuitive to normal light responses and oppose red- and blue-light-induced responses. Green light effects on plant growth and development are described here through the use of custom, tunable LED, light-emitting diode, chambers. These light sources allow for specific light qualities and quantities to be administered. The effects of green wavebands were assessed when red and blue photomorphogenic systems were active to answer the question: Are the effects of an inhibitor (green light) more evident in the presence of inducers (red and blue light)? In seedlings, supplemental green light increased hypocotyl elongation opposite to classical inhibition of hypocotyl elongation associated with growth in light and induced by red and blue wavebands. Results indicate that added green light induced a reversion of light-grown phenotypes. In mature plants, supplemental green light induced phenotypes typical of the shade-avoidance syndrome, including elongated petioles, smaller leaf areas, and leaf hyponasty. These responses are typical of lower-light conditions or far-red enriched environments. Contrary to far-red-light-induced shade-avoidance, data indicate green delays flowering. In Arabidopsis and strawberry plants, anthocyanin levels also decreased when green light was added to red and blue light treatments, which is again opposite to normal light-induced phenotypes. Photoreceptor mutants were tested and indicate green light effects in early development are cryptochromedependent. However, green-light-induced shade-avoidance responses were cryptochrome-independent. A candidate gene approach was used to identify other elements required for green light sensing and/or response. Defects in some green light responses were observed for mutants in CCD8/Max4, a putative carotenoid cleavage enzyme with high sequence similarity to a critical enzyme in animal vision. These data support a role for green light in plant development which opposes normal light-induced responses and indicate the existence of at least two green light sensing systems.

Light-emitting device with organic electroluminescent material and photoluminescent materials

DOEpatents

McNulty, Thomas Francis; Duggal, Anil Raj; Turner, Larry Gene; Shiang, Joseph John

2005-06-07

A light-emitting device comprises a light-emitting member, which comprises two electrodes and an organic electroluminescent material disposed between the electrodes, and at least one organic photoluminescent ("PL") material. The light-emitting member emits light having a first spectrum in response to a voltage applied across the two electrodes. The organic PL material absorbs a portion of the light emitted by the light-emitting member and emits light having second spectrum different than the first spectrum. The light-emitting device can include an inorganic PL material that absorbs another portion of the light emitted from the light-emitting member and emits light having a third spectrum different than both the first and the second spectra.

Effects of supplementary lighting by natural light for growth of Brassica chinensis

NASA Astrophysics Data System (ADS)

Yeh, Shih-Chuan; Lee, Hui-Ping; Kao, Shih-Tse; Lu, Ju-Lin

2016-04-01

This paper present a model of cultivated chamber with supplementary natural colour light. We investigate the effects of supplementary natural red light and natural blue light on growth of Brassica chinensis under natural white light illumination. After 4 weeks of supplementary colour light treatment, the experiment results shown that the weight of fresh leaf were not affected by supplementary natural blue light. However, those Brassica chinensis were cultivated in the chambers with supplementary natural red light obtained a significant increasing of fresh weight of leaf under both white light illuminate models. The combination of natural white light with supplementary natural red light illumination will be benefits in growth for cultivation and energy saving.

Use of diffusive optical fibers for plant lighting

NASA Technical Reports Server (NTRS)

Kozai, T.; Kitaya, Y.; Fujiwara, K.; Kino, S.; Kinowaki, M.

1994-01-01

Lighting is one of the most critical aspects in plant production and environmental research with plants. Much research has been repeated on the effect of light intensity, spectral distribution of light and lighting cycle, but comparatively little research done on the effect of lighting direction on the growth, development and morphology of plants. When plants are grown with lamps above, light is directed downward to the plants. Downward or overhead lighting is utilized in almost all cases. However, downward lighting does not always give the best result in terms of lighting efficiency, growth, development and morphology of plants. In the present study, a sideward lighting system was developed using diffusive optical fiber belts. More higher quality tissue-cultured transplants could be produced in a reduced space with the sideward lighting system than with a downward lighting system. An application of the sideward lighting system using diffusive optical fiber belts is described and the advantages and disadvantages are discussed.

Spectrally balanced chromatic landing approach lighting system

NASA Technical Reports Server (NTRS)

Chase, W. D. (Inventor)

1981-01-01

Red warning lights delineate the runway approach with additional blue lights juxtaposed with the red lights such that the red lights are chromatically balanced. The red/blue point light sources result in the phenomenon that the red lights appear in front of the blue lights with about one and one-half times the diameter of the blue. To a pilot observing these lights along a glide path, those red lights directly below appear to be nearer than the blue lights. For those lights farther away seen in perspective at oblique angles, the red lights appear to be in a position closer to the pilot and hence appear to be above the corresponding blue lights. This produces a very pronounced three dimensional effect referred to as chromostereopsis which provides valuable visual cues to enable the pilot to perceive his actual position above the ground and the actual distance to the runway.

Use of diffusive optical fibers for plant lighting

NASA Astrophysics Data System (ADS)

Kozai, T.; Kitaya, Y.; Fujiwara, K.; Kino, S.; Kinowaki, M.

1994-03-01

Lighting is one of the most critical aspects in plant production and environmental research with plants. Much research has been repeated on the effect of light intensity, spectral distribution of light and lighting cycle, but comparatively little research done on the effect of lighting direction on the growth, development and morphology of plants. When plants are grown with lamps above, light is directed downward to the plants. Downward or overhead lighting is utilized in almost all cases. However, downward lighting does not always give the best result in terms of lighting efficiency, growth, development and morphology of plants. In the present study, a sideward lighting system was developed using diffusive optical fiber belts. More higher quality tissue-cultured transplants could be produced in a reduced space with the sideward lighting system than with a downward lighting system. An application of the sideward lighting system using diffusive optical fiber belts is described and the advantages and disadvantages are discussed.

Choosing surgical lighting in the LED era.

PubMed

Knulst, Arjan J; Stassen, Laurents P S; Grimbergen, Cornelis A; Dankelman, Jenny

2009-12-01

The aim of this study is to evaluate the illumination characteristics of LED lights objectively to ease the selection of surgical lighting. The illuminance distributions of 5 main and 4 auxiliary lights were measured in 8 clinically relevant scenarios. For each light and scenario, the maximum illuminance E(c) (klux) and the size of the light field d(10) (mm) were computed. The results showed: that large variations for both E(c) (25-160 klux) and d(10) (109-300 mm) existed; that using auxiliary lights reduced both E(c) and d(10) by up to 80% and 30%; that with segmented lights, uneven light distributions occurred; and that with colored LED lights shadow edges on the surgical field became colored. Objective illuminance measurements show a wide variation between lights and a superiority of main over auxiliary lights. Uneven light distributions and colored shadows indicate that LED lights still need to converge to an optimal design.

Light extraction block with curved surface

DOEpatents

Levermore, Peter; Krall, Emory; Silvernail, Jeffrey; Rajan, Kamala; Brown, Julia J.

2016-03-22

Light extraction blocks, and OLED lighting panels using light extraction blocks, are described, in which the light extraction blocks include various curved shapes that provide improved light extraction properties compared to parallel emissive surface, and a thinner form factor and better light extraction than a hemisphere. Lighting systems described herein may include a light source with an OLED panel. A light extraction block with a three-dimensional light emitting surface may be optically coupled to the light source. The three-dimensional light emitting surface of the block may includes a substantially curved surface, with further characteristics related to the curvature of the surface at given points. A first radius of curvature corresponding to a maximum principal curvature k.sub.1 at a point p on the substantially curved surface may be greater than a maximum height of the light extraction block. A maximum height of the light extraction block may be less than 50% of a maximum width of the light extraction block. Surfaces with cross sections made up of line segments and inflection points may also be fit to approximated curves for calculating the radius of curvature.

Double-layered liquid crystal light shutter for control of absorption and scattering of the light incident to a transparent display device

NASA Astrophysics Data System (ADS)

Huh, Jae-Won; Yu, Byeong-Hun; Shin, Dong-Myung; Yoon, Tae-Hoon

2015-03-01

Recently, a transparent display has got much attention as one of the next generation display devices. Especially, active studies on a transparent display using organic light-emitting diodes (OLEDs) are in progress. However, since it is not possible to obtain black color using a transparent OLED, it suffers from poor visibility. This inevitable problem can be solved by using a light shutter. Light shutter technology can be divided into two types; light absorption and scattering. However, a light shutter based on light absorption cannot block the background image perfectly and a light shutter based on light scattering cannot provide black color. In this work we demonstrate a light shutter using two liquid crystal (LC) layers, a light absorption layer and a light scattering layer. To realize a light absorption layer and a light scattering layer, we use the planar state of a dye-doped chiral nematic LC (CNLC) cell and the focal-conic state of a long-pitch CNLC cell, respectively. The proposed light shutter device can block the background image perfectly and show black color. We expect that the proposed light shutter can increase the visibility of a transparent display.

The Acute Effects of Intermittent Light Exposure in the Evening on Alertness and Subsequent Sleep Architecture.

PubMed

Yang, Minqi; Ma, Ning; Zhu, Yingying; Su, Ying-Chu; Chen, Qingwei; Hsiao, Fan-Chi; Ji, Yanran; Yang, Chien-Ming; Zhou, Guofu

2018-03-15

Exposure to bright light is typically intermittent in our daily life. However, the acute effects of intermittent light on alertness and sleep have seldom been explored. To investigate this issue, we employed within-subject design and compared the effects of three light conditions: intermittent bright light (30-min pulse of blue-enriched bright light (~1000 lux, ~6000 K) alternating with 30-min dim normal light (~5 lux, ~3600 K) three times); continuous bright light; and continuous dim light on subjective and objective alertness and subsequent sleep structure. Each light exposure was conducted during the three hours before bedtime. Fifteen healthy volunteers (20 ± 3.4 years; seven males) were scheduled to stay in the sleep laboratory for four separated nights (one for adaptation and the others for the light exposures) with a period of at least one week between nights. The results showed that when compared with dim light, both intermittent light and continuous bright light significantly increased subjective alertness and decreased sleep efficiency (SE) and total sleep time (TST). Intermittent light significantly increased objective alertness than dim light did during the second half of the light-exposure period. Our results suggested that intermittent light was as effective as continuous bright light in their acute effects in enhancing subjective and objective alertness and in negatively impacting subsequent sleep.

Utility and safety of a novel surgical microscope laser light source

PubMed Central

Bakhit, Mudathir S.; Suzuki, Kyouichi; Sakuma, Jun; Fujii, Masazumi; Murakami, Yuta; Ito, Yuhei; Sugano, Tetsuo; Saito, Kiyoshi

2018-01-01

Objective Tissue injuries caused by the thermal effects of xenon light microscopes have previously been reported. Due to this, the development of a safe microscope light source became a necessity. A newly developed laser light source is evaluated regarding its effectiveness and safety as an alternative to conventional xenon light source. Methods We developed and tested a new laser light source for surgical microscopes. Four experiments were conducted to compare xenon and laser lights: 1) visual luminance comparison, 2) luminous and light chromaticity measurements, 3) examination and analysis of visual fatigue, and 4) comparison of focal temperature elevation due to light source illumination using porcine muscle samples. Results Results revealed that the laser light could be used at a lower illumination value than the xenon light (p < 0.01). There was no significant difference in visual fatigue status between the laser light and the xenon light. The laser light was superior to the xenon light regarding luminous intensity and color chromaticity. The focal temperature elevation of the muscle samples was significantly higher when irradiated with xenon light in vitro than with laser light (p < 0.01). Conclusion The newly developed laser light source is more efficient and safer than a conventional xenon light source. It lacks harmful ultraviolet waves, has a longer lifespan, a lower focal temperature than that of other light sources, a wide range of brightness and color production, and improved safety for the user’s vision. Further clinical trials are necessary to validate the impact of this new light source on the patient’s outcome and prognosis. PMID:29390016

Use of diffusive optical fibers for plant lighting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozai, T.; Kitaya, Y.; Fujiwara, K.

1994-12-31

Lighting is one of the most critical aspects in plant production and environmental research with plants. Much research has been repeated on the effect of light intensity, spectral distribution of light and lighting cycle, but comparatively little research done on the effect of lighting direction on the growth, development and morphology of plants. When plants are grown with lamps above, light is directed downward to the plants. Downward or overhead lighting is utilized in almost all cases. However, downward lighting does not always give the best result in terms of lighting efficiency, growth, development and morphology of plants. Kitaya etmore » al. (1988) developed a lighting system in which two rooting beds were arranged; one above and the other under fluorescent lamps. Lettuce plants grew normally in the lower bed and suspended upside-down under the upper bed. The lettuce plants suspended upside-down were given the light in upward direction (upward lighting). No significant difference in growth, development and morphology was found between the lettuce plants grown by the downward and upward lighting. Combining upward and downward lighting, improved spacing efficiency and reduced electricity cost per plant compared with conventional, downward lighting. From the above example, when designing a lighting system for plants with lamps more lighting direction should be considered. In the present study, a sideward lighting system was developed using diffusive optical fiber belts. More higher quality tissue-cultured transplants could be produced in reduced space with sideward lighting system than with a downward lighting system. An application of the sideward lighting system using diffusive optical fiber belts is described and advantages and disadvantages are discussed.« less

Light and Libraries.

ERIC Educational Resources Information Center

Scherer, Jeffrey

1999-01-01

Addresses how to integrate various types of light within the context of library design. Discusses light basics; the light spectrum; light measurement; reflectance; glare and brightness ratio; daylighting; electric lighting; and computer screens and lighting. Includes a checklist for plan review. (Author/LRW)

Scanning computed confocal imager

DOEpatents

George, John S.

2000-03-14

There is provided a confocal imager comprising a light source emitting a light, with a light modulator in optical communication with the light source for varying the spatial and temporal pattern of the light. A beam splitter receives the scanned light and direct the scanned light onto a target and pass light reflected from the target to a video capturing device for receiving the reflected light and transferring a digital image of the reflected light to a computer for creating a virtual aperture and outputting the digital image. In a transmissive mode of operation the invention omits the beam splitter means and captures light passed through the target.

Subadditive responses to extremely short blue and green pulsed light on visual evoked potentials, pupillary constriction and electroretinograms.

PubMed

Lee, Soomin; Uchiyama, Yuria; Shimomura, Yoshihiro; Katsuura, Tetsuo

2017-11-17

The simultaneous exposure to blue and green light was reported to result in less melatonin suppression than monochromatic exposure to blue or green light. Here, we conducted an experiment using extremely short blue- and green-pulsed light to examine their visual and nonvisual effects on visual evoked potentials (VEPs), pupillary constriction, electroretinograms (ERGs), and subjective evaluations. Twelve adult male subjects were exposed to three light conditions: blue-pulsed light (2.5-ms pulse width), green-pulsed light (2.5-ms pulse width), and simultaneous blue- and green-pulsed light with white background light. We measured the subject's pupil diameter three times in each condition. Then, after 10 min of rest, the subject was exposed to the same three light conditions. We measured the averaged ERG and VEP during 210 pulsed-light exposures in each condition. We also determined subjective evaluations using a visual analog scale (VAS) method. The pupillary constriction during the simultaneous exposure to blue- and green-pulsed light was significantly lower than that during the blue-pulsed light exposure despite the double irradiance intensity of the combination. We also found that the b/|a| wave of the ERGs during the simultaneous exposure to blue- and green-pulsed light was lower than that during the blue-pulsed light exposure. We confirmed the subadditive response to pulsed light on pupillary constriction and ERG. However, the P100 of the VEPs during the blue-pulsed light were smaller than those during the simultaneous blue- and green-pulsed light and green-pulsed light, indicating that the P100 amplitude might depend on the luminance of light. Our findings demonstrated the effect of the subadditive response to extremely short pulsed light on pupillary constriction and ERG responses. The effects on ipRGCs by the blue-pulsed light exposure are apparently reduced by the simultaneous irradiation of green light. The blue versus yellow (b/y) bipolar cells in the retina might be responsible for this phenomenon.

PFP Emergency Lighting Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

BUSCH, M.S.

2000-02-02

NFPA 101, section 5-9 mandates that, where required by building classification, all designated emergency egress routes be provided with adequate emergency lighting in the event of a normal lighting outage. Emergency lighting is to be arranged so that egress routes are illuminated to an average of 1.0 footcandle with a minimum at any point of 0.1 footcandle, as measured at floor level. These levels are permitted to drop to 60% of their original value over the required 90 minute emergency lighting duration after a power outage. The Plutonium Finishing Plant (PFP) has two designations for battery powered egress lights ''Emergencymore » Lights'' are those battery powered lights required by NFPA 101 to provide lighting along officially designated egress routes in those buildings meeting the correct occupancy requirements. Emergency Lights are maintained on a monthly basis by procedure ZSR-12N-001. ''Backup Lights'' are battery powered lights not required by NFPA, but installed in areas where additional light may be needed. The Backup Light locations were identified by PFP Safety and Engineering based on several factors. (1) General occupancy and type of work in the area. Areas occupied briefly during a shiftly surveillance do not require backup lighting while a room occupied fairly frequently or for significant lengths of time will need one or two Backup lights to provide general illumination of the egress points. (2) Complexity of the egress routes. Office spaces with a standard hallway/room configuration will not require Backup Lights while a large room with several subdivisions or irregularly placed rooms, doors, and equipment will require Backup Lights to make egress safer. (3) Reasonable balance between the safety benefits of additional lighting and the man-hours/exposure required for periodic light maintenance. In some plant areas such as building 236-Z, the additional maintenance time and risk of contamination do not warrant having Backup Lights installed in all rooms. Sufficient light for egress is provided by existing lights located in the hallways.« less

The effect of reinforcement differences on choice and response distribution during stimulus compounding.

PubMed

Bushnell, M C; Weiss, S J

1977-03-01

In Experiments I and II, rats were trained to respond on one lever during light and another during tone. The absence of tone and light controlled response cessation. In the multiple schedule of Experiment I, all reinforcements were received for responding in tone or light; in the chain schedule of Experiment II, all reinforcements were received in no tone + no light for not responding. Experiment I subjects, for which tone and light were associated with response and reinforcement increase, responded significantly more to tone-plus-light than to tone or light alone (additive summation). Experiment II subjects, for which tone and light were associated with response increase and reinforcement decrease, responded comparably to tone, light, and tone + light. Thus, additive summation was observed when stimulus-response and stimulus-reinforcer associations in tone and light were both positive, but not when they were conflicting. All subjects in both experiments responded predominantly on the light-correlated lever during tone + light, even when light intensity was reduced in testing. Furthermore, when a light was presented to a subject engaged in tone-associated responding, all subjects immediately switched the locus of responding to the light-correlated lever. No change in locus occurred when a tone was presented to a subject engaged in light-associated responding, irrespective of the stimulus-reinforcer association conditioned to tone. The light-lever preference in tone + light indicates that the heightened responding observed in Experiment I was not the summation of tone-associated behavior with light-associated behavior. Rather, it appears to be the result of a facilitation of one operant (light-associated responding) by the reinforcement-associated cue for the other.

Effects of Different Viewing Conditions on Radiographic Interpretation

PubMed Central

Moshfeghi, Mahkameh; Shahbazian, Majid; Sajadi, Soodabeh Sadat; Sajadi, Sepideh; Ansari, Hossein

2015-01-01

Objectives: Optimum viewing conditions facilitate identification of radiographic details and decrease the need for retakes, patients’ costs and radiation dose. This study sought to evaluate the effects of different viewing conditions on radiographic interpretation. Materials and Methods: This diagnostic study was performed by evaluating radiograph of a 7mm-thick aluminum block, in which 10 holes with 2mm diameters were randomly drilled with depths ranging from 0.05 mm to 0.50mm. The radiograph was viewed by four oral radiologists independently under four viewing conditions, including a white light viewing light box in a lit room, yellow light viewing light box in a lit room, white light viewing light box in a dark room and yellow light viewing light box in a dark room. Number of circular shadows observed on the film was recorded. The data were analyzed by two-way ANOVA. Results: The mean number of detected circular shadows was 6.75, 7.5, 7.25 and 7.75 in white light viewing light box in a lit room, white light viewing light box in a dark room, yellow light viewing light box in a lit room and yellow light viewing light box in a dark room, respectively. Although the surrounding illumination had statistically significant effect on the radiographic details (P≤0.03), the light color of the viewing light box had no significant effect on visibility of the radiographic details. Conclusion: White and yellow light of the viewing light box had no significant effect on visibility of the radiographic details but more information was obtained in a dark room. PMID:27507997

Effects of Different Viewing Conditions on Radiographic Interpretation.

PubMed

Moshfeghi, Mahkameh; Shahbazian, Majid; Sajadi, Soodabeh Sadat; Sajadi, Sepideh; Ansari, Hossein

2015-11-01

Optimum viewing conditions facilitate identification of radiographic details and decrease the need for retakes, patients' costs and radiation dose. This study sought to evaluate the effects of different viewing conditions on radiographic interpretation. This diagnostic study was performed by evaluating radiograph of a 7mm-thick aluminum block, in which 10 holes with 2mm diameters were randomly drilled with depths ranging from 0.05 mm to 0.50mm. The radiograph was viewed by four oral radiologists independently under four viewing conditions, including a white light viewing light box in a lit room, yellow light viewing light box in a lit room, white light viewing light box in a dark room and yellow light viewing light box in a dark room. Number of circular shadows observed on the film was recorded. The data were analyzed by two-way ANOVA. The mean number of detected circular shadows was 6.75, 7.5, 7.25 and 7.75 in white light viewing light box in a lit room, white light viewing light box in a dark room, yellow light viewing light box in a lit room and yellow light viewing light box in a dark room, respectively. Although the surrounding illumination had statistically significant effect on the radiographic details (P≤0.03), the light color of the viewing light box had no significant effect on visibility of the radiographic details. White and yellow light of the viewing light box had no significant effect on visibility of the radiographic details but more information was obtained in a dark room.

Compact imaging spectrometer utilizing immersed gratings

DOEpatents

Lerner, Scott A.

2005-12-20

A compact imaging spectrometer comprising an entrance slit for directing light, lens means for receiving the light, refracting the light, and focusing the light; an immersed diffraction grating that receives the light from the lens means and defracts the light, the immersed diffraction grating directing the detracted light back to the lens means; and a detector that receives the light from the lens means.

A Guide to the Librarian's Responsibility in Achieving Quality in Lighting and Ventilation.

ERIC Educational Resources Information Center

Mason, Ellsworth

1967-01-01

Quality, not intensity, is the keystone to good library lighting. The single most important problem in lighting is glare caused by extremely intense centers of light. Multiple interfiling of light rays is a factor required in library lighting. A fixture that diffuses light well is basic when light emerges from the fixture. It scatters widely,…

Effects of type of light on mouse circadian behaviour and stress levels.

PubMed

Alves-Simoes, Marta; Coleman, Georgia; Canal, Maria Mercè

2016-02-01

Light is the principal synchronizing environmental factor for the biological clock. Light quantity (intensity), and light quality (type of light source) can have different effects. The aim of this study was to determine the effects of the type of light experienced from the time of birth on mouse growth, circadian behaviour and stress levels. We raised pigmented and albino mice under 24 h light-dark cycles of either fluorescent or white light-emitting diode (LED) light source during the suckling stage, and the animals were then exposed to various light environments after weaning and their growth rate, locomotor activity and plasma corticosterone concentration were measured. We found that the type of light the animals were exposed to did not affect the animals' growth rates or stress levels. However, we observed significant effects on the expression of the locomotor activity rhythm under low contrast light-dark cycles in pigmented mice, and under constant light in both albino and pigmented mice. These results highlight the importance of environmental light quality (light source) on circadian behavioural rhythms, and the need for close monitoring of light environments in animal facilities. © The Author(s) 2015.

3. View from former light tower to Cape Elizabeth Light ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. View from former light tower to Cape Elizabeth Light Tower, view northeast, southwest side of Cape Elizabeth Tower - Cape Elizabeth Light Station, Near Two Lights State Park at end of Two Lights Road, off State Highway 77, Cape Elizabeth, Cumberland County, ME

Virtual reality to simulate large lighting with high efficiency LEDs

NASA Astrophysics Data System (ADS)

Blandet, Thierry; Coutelier, Gilles; Meyrueis, Patrick

2011-05-01

When a city or a local authority wishes to emphasize its historical heritage, for the lighting of its streets, setting up lights during the festive season, they call upon the skills of a lighting designer. The lighting designer proposes concepts, ideas, lighting, and to be able to present them, he makes use of simulation. On the other hand lighting technologies are evolving very rapidly and new lighting systems offer features that lighting designers are now integrating their projects. The street lights consume lot of energy; light projects are now taking into account the energy saving aspect. Lighting systems based on LEDs today provide good lighting needs, taking into account sustainable development issues while enabling new creative dimension. The lighting simulation can handle these parameters. Images or video simulation are no longer sufficient: stereoscopy and virtual reality techniques allow better communication and better understanding of projects. Virtual reality offers new possibilities of interaction, the freedom of movement in a scene, the presentation of variants or interactive simulations.

Intramolecular co-action of two independent photosensory modules in the fern phytochrome 3.

PubMed

Kanegae, Takeshi

2015-01-01

Fern phytochrome3/neochrome1 (phy3/neo1) is a chimeric photoreceptor composed of a phytochrome-chromophore binding domain and an almost full-length phototropin. phy3 thus contains two different light-sensing modules; a red/far-red light receptor phytochrome and a blue light receptor phototropin. phy3 induces both red light- and blue light-dependent phototropism in phototropin-deficient Arabidopsis thaliana (phot1 phot2) seedlings. The red-light response is dependent on the phytochrome module of phy3, and the blue-light response is dependent on the phototropin module. We recently showed that both the phototropin-sensing module and the phytochrome-sensing module mediate the blue light-dependent phototropic response. Particularly under low-light conditions, these two light-sensing modules cooperate to induce the blue light-dependent phototropic response. This intramolecular co-action of two independent light-sensing modules in phy3 enhances light sensitivity, and perhaps allowed ferns to adapt to the low-light canopy conditions present in angiosperm forests.

Comparison of light transmittance in different thicknesses of zirconia under various light curing units

PubMed Central

Egilmez, Ferhan; Ergun, Gulfem

2012-01-01

PURPOSE The objective of this study was to compare the light transmittance of zirconia in different thicknesses using various light curing units. MATERIALS AND METHODS A total of 21 disc-shaped zirconia specimens (5 mm in diameter) in different thicknesses (0.3, 0.5 and 0.8 mm) were prepared. The light transmittance of the specimens under three different light-curing units (quartz tungsten halogen, light-emitting diodes and plasma arc) was compared by using a hand-held radiometer. Statistical significance was determined using two-way ANOVA (α=.05). RESULTS ANOVA revealed that thickness of zirconia and light curing unit had significant effects on light transmittance (P<.001). CONCLUSION Greater thickness of zirconia results in lower light transmittance. Light-emitting diodes light-curing units might be considered as effective as Plasma arc light-curing units or more effective than Quartz-tungsten-halogen light-curing units for polymerization of the resin-based materials. PMID:22737314

Effect of inhomogeneity of light from light curing units on the surface hardness of composite resin.

PubMed

Arikawa, Hiroyuki; Kanie, Takahito; Fujii, Koichi; Takahashi, Hideo; Ban, Seiji

2008-01-01

This study investigated the characteristics of output light from different types of light curing units, and their effects on polymerization of light-activated composite resin. Three quartz-tungsten-halogen lamps, one plasma arc lamp, and one LED light curing unit were used. Intensity distribution of light emitted from the light guide tip was measured at 1.0-mm intervals across the guide tip. Distribution of Knoop hardness number on the surface of resin irradiated with the light curing units was also measured. For all units, inhomogeneous distribution of light intensity across the guide tip was observed. Minimum light intensity values were 19-80% of the maximum values. In terms of surface hardness, inhomogeneous distribution was also observed for the materials irradiated with the tested units. Minimum values were 53-92% of the maximum values. Our results indicated that markedly inhomogeneous light emitted from light curing unit could result in inhomogeneous polymerization in some areas of the restoration below the light guide tip.

Transparent selective illumination means suitable for use in optically activated electrical switches and optically activated electrical switches constructed using same

DOEpatents

Wilcox, R.B.

1991-09-10

A planar transparent light conducting means and an improved optically activated electrical switch made using the novel light conducting means are disclosed. The light conducting means further comprise light scattering means on one or more opposite planar surfaces thereof to transmit light from the light conducting means into adjacent media and reflective means on other surfaces of the light conducting means not containing the light scattering means. The optically activated electrical switch comprises at least two stacked photoconductive wafers, each having electrodes formed on both surfaces thereof, and separated by the planar transparent light conducting means. The light scattering means on the light conducting means face surfaces of the wafers not covered by the electrodes to transmit light from the light conducting means into the photoconductive wafers to uniformly illuminate and activate the switch. 11 figures.

Transparent selective illumination means suitable for use in optically activated electrical switches and optically activated electrical switches constructed using same

DOEpatents

Wilcox, Russell B.

1991-01-01

A planar transparent light conducting means and an improved optically activated electrical switch made using the novel light conducting means are disclosed. The light conducting means further comprise light scattering means on one or more opposite planar surfaces thereof to transmit light from the light conducting means into adjacent media and reflective means on other surfaces of the light conducting means not containing the light scattering means. The optically activated electrical switch comprises at least two stacked photoconductive wafers, each having electrodes formed on both surfaces thereof, and separated by the planar transparent light conducting means. The light scattering means on the light conducting means face surfaces of the wafers not covered by the electrodes to transmit light from the light conducting means into the photoconductive wafers to uniformly illuminate and activate the switch.

The design of the light-flash warning light

NASA Astrophysics Data System (ADS)

Wang, Junli

2018-05-01

In today's society, the warning light has been used widely in people's daily life and various industries and agricultures. It is important to protect people's life and security. Light-flashing warning light is a kind of warning light control equipment which can control warning light automatically open and work in the state of blinking after dark, and it can automatically shut down after the dawn. It can achieve the flashing light automatic control and dual function. At present, light-flashing warning lights are mainly used in the projects of municipal construction. It is helpful to warn people and vehicles that passed in the construction site and ensure personal safety through using light-flashing warning light. Its design is simple, its performance is stable and it is also very convince to use it.

NASA Lighting Research, Test, & Analysis

NASA Technical Reports Server (NTRS)

Clark, Toni

2015-01-01

The Habitability and Human Factors Branch, at Johnson Space Center, in Houston, TX, provides technical guidance for the development of spaceflight lighting requirements, verification of light system performance, analysis of integrated environmental lighting systems, and research of lighting-related human performance issues. The Habitability & Human Factors Lighting Team maintains two physical facilities that are integrated to provide support. The Lighting Environment Test Facility (LETF) provides a controlled darkroom environment for physical verification of lighting systems with photometric and spetrographic measurement systems. The Graphics Research & Analysis Facility (GRAF) maintains the capability for computer-based analysis of operational lighting environments. The combined capabilities of the Lighting Team at Johnson Space Center have been used for a wide range of lighting-related issues.

Das Ende der Nacht [The End of the Night (2nd enlarged ed.)

NASA Astrophysics Data System (ADS)

Posch, Thomas; Hölker, Franz; Uhlmann, Thomas; Freyhoff, Anja

2013-09-01

We provide provide an overview of the history of lighting and of the problems arising from artificial lighting. The book covers the following topics: A brief history of light (ch. 1); night and light in cultural history (ch. 2); light pollution in central Europe (ch. 3); Moths and artificial lights (ch. 4); Artificial lighting and birds (ch. 5); Ocean turtles as victims of beach lighting (ch. 6); Moon light as a zeitgeber for the marine fauna (ch. 7); the influence of artificial light at night on freshwater ecology (ch. 8); artificial light and human health (ch. 9); the loss of the night in a 24 hours society (ch. 10).

Compact Refractive Imaging Spectrometer Designs Utilizing Immersed Gratings

DOEpatents

Lerner, Scott A.; Bennett, Charles L.; Bixler, Jay V.; Kuzmenko, Paul J.; Lewis, Isabella T.

2005-07-26

A compact imaging spectrometer comprising an entrance slit for directing light, a first means for receiving the light and focusing the light, an immersed diffraction grating that receives the light from the first means and defracts the light, a second means for receiving the light from the immersed diffraction grating and focusing the light, and an image plane that receives the light from the second means

The quantitative models for broiler chicken response to monochromatic, combined, and mixed light-emitting diode light: A meta-analysis.

PubMed

Yang, Yefeng; Pan, Chenhao; Zhong, Renhai; Pan, Jinming

2018-06-01

Although many experiments have been conducted to clarify the response of broiler chickens to light-emitting diode (LED) light, those published results do not provide a solid scientific basis for quantifying the response of broiler chickens. This study used a meta-analysis to establish light spectral models of broiler chickens. The results indicated that 455 to 495 nm blue LED light produced the greatest positive response in body weight by 10.66% (BW; P < 0.001) and 515 to 560 nm green LED light increased BW by 6.27% (P < 0.001) when compared with white light. Regression showed that the wavelength (455 to 660 nm) was negatively related to BW change of birds, with a decrease of about 4.9% BW for each 100 nm increase in wavelength (P = 0.002). Further analysis suggested that a combination of the two beneficial light sources caused a synergistic effect. BW was further increased in birds transferred either from green LED light to blue LED light (17.23%; P < 0.001) or from blue LED light to green LED light (17.52%; P < 0.001). Moreover, birds raised with a mixture of green and blue LED light showed a greater BW promotion (10.66%; P < 0.001) than those raised with green LED light (6.27%). A subgroup analysis indicated that BW response to monochromatic LED light was significant regardless of the genetic strain, sex, control light sources, light intensity and regime of LED light, environmental temperature, and dietary ME and CP (P > 0.05). However, there was an interaction between the FCR response to monochromatic LED light with those covariant factors (P < 0.05). Additionally, green and yellow LED light played a role in affecting the meat color, quality, and nutrition of broiler chickens. The results indicate that the optimal ratio of green × blue of mixed LED light or shift to green-blue of combined LED light may produce the optimized production performance, whereas the optimal ratio of green/yellow of mixed or combined LED light may result in the optimized meat quality.

Generating the Nighttime Light of the Human Settlements by Identifying Periodic Components from DMSP/OLS Satellite Imagery.

PubMed

Letu, Husi; Hara, Masanao; Tana, Gegen; Bao, Yuhai; Nishio, Fumihiko

2015-09-01

Nighttime lights of the human settlements (hereafter, "stable lights") are seen as a valuable proxy of social economic activity and greenhouse gas emissions at the subnational level. In this study, we propose an improved method to generate the stable lights from Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) daily nighttime light data for 1999. The study area includes Japan, China, India, and other 10 countries in East Asia. A noise reduction filter (NRF) was employed to generate a stable light from DMSP/OLS time-series daily nighttime light data. It was found that noise from amplitude of the 1-year periodic component is included in the stable light. To remove the amplitude of the 1-year periodic component noise included in the stable light, the NRF method was improved to extract the periodic component. Then, new stable light was generated by removing the amplitude of the 1-year periodic component using the improved NRF method. The resulting stable light was evaluated by comparing it with the conventional nighttime stable light provided by the National Oceanic and Atmosphere Administration/National Geophysical Data Center (NOAA/NGDC). It is indicated that DNs of the NOAA stable light image are lower than those of the new stable light image. This might be attributable to the influence of attenuation effects from thin warm water clouds. However, due to overglow effect of the thin cloud, light area in new stable light is larger than NOAA stable light. Furthermore, the cumulative digital numbers (CDNs) and number of light area pixels (NLAP) of the generated stable light and NOAA/NGDC stable light were applied to estimate socioeconomic variables of population, electric power consumption, gross domestic product, and CO2 emissions from fossil fuel consumption. It is shown that the correlations of the population and CO2FF with new stable light data are higher than those in NOAA stable light data; correlations of the EPC and GDP with NOAA stable light data are higher those in the new stable light data.

Close correspondence between the action spectra for the blue light responses of the guard cell and coleoptile chloroplasts, and the spectra for blue light-dependent stomatal opening and coleoptile phototropism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quinones, M.A.; Lu, Zhenmin; Zeiger, E.

1996-03-05

Fluorescence spectroscopy was used to characterize blue light responses from chloroplasts of adaxial guard cells from Pima cotton (Gossypium barbadense) and coleoptile tips from corn (Zea mays). The chloroplast response to blue light was quantified by measurements of the blue light-induced enhancement of a red light-stimulated quenching of chlorophyll a fluorescence. In adaxial (upper) guard cells, low fluence rates of blue light applied under saturating fluence rates of red light enhanced the red light-stimulated fluorescence quenching by up to 50%. In contrast, added blue light did not alter the red light-stimulated quenching from abaxial (lower) guard cells. This response patternmore » paralleled the blue light sensitivity of stomatal opening in the two leaf surfaces. An action spectrum for the blue light-induced enhancement of the red light-stimulated quenching showed a major peak at 450 nm and two minor peaks at 420 and 470 nm. This spectrum matched closely an action spectrum for blue light-stimulated stomatal opening. Coleoptile chloroplasts also showed an enhancement by blue light of red light-stimulated quenching. The action spectrum of this response, showing a major peak at 450 nm, a minor peak at 470 nm, and a shoulder at 430 nm, closely matched an action spectrum for blue light-stimulated coleoptile phototropism. Both action spectra match the absorption spectrum of zeaxanthin, a chloroplastic carotenoid recently implicated in blue light photoreception of both guard cells and coleoptiles. The remarkable similarity between the action spectra for the blue light responses of guard cells and coleoptile chloroplasts and the spectra for blue light-stimulated stomatal opening and phototropism, coupled to the recently reported evidence on a role of zeaxanthin in blue light photoreception, indicates that the guard cell and coleoptile chloroplasts specialize in sensory transduction. 28 refs. 4 figs.« less

Talking with Children about Light.

ERIC Educational Resources Information Center

Texas Child Care, 1996

1996-01-01

Suggests caregivers can help children learn about the concept of light using simple conversation and activities. Offers directions for activities in which children can consider the following questions about light: where does light come from?; can you see without light?; what blocks light?; how does light travel?; can you make a shadow?; and does…

47 CFR 80.864 - Emergency electric lights.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Emergency electric lights. 80.864 Section 80... W § 80.864 Emergency electric lights. (a) Emergency electric light(s) must be installed to...) The emergency electric light(s) must be energized from the reserve power supply, if a reserve power...

47 CFR 80.864 - Emergency electric lights.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Emergency electric lights. 80.864 Section 80... W § 80.864 Emergency electric lights. (a) Emergency electric light(s) must be installed to...) The emergency electric light(s) must be energized from the reserve power supply, if a reserve power...

47 CFR 80.864 - Emergency electric lights.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Emergency electric lights. 80.864 Section 80... W § 80.864 Emergency electric lights. (a) Emergency electric light(s) must be installed to...) The emergency electric light(s) must be energized from the reserve power supply, if a reserve power...

47 CFR 80.864 - Emergency electric lights.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Emergency electric lights. 80.864 Section 80... W § 80.864 Emergency electric lights. (a) Emergency electric light(s) must be installed to...) The emergency electric light(s) must be energized from the reserve power supply, if a reserve power...

47 CFR 80.864 - Emergency electric lights.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Emergency electric lights. 80.864 Section 80... W § 80.864 Emergency electric lights. (a) Emergency electric light(s) must be installed to...) The emergency electric light(s) must be energized from the reserve power supply, if a reserve power...

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

PubMed

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 (<10, 100, 300, 900 and 2700 lx) between the hours of 09:00 and 12:00 (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.

Improved aethalometer

DOEpatents

Hansen, A.D.

1988-01-25

An improved aethalometer having a single light source and a single light detector and two light paths from the light source to the light detector. A quartz fiber filter is inserted in the device, the filter having a collection area in one light path and a reference area in the other light path. A gas flow path through the aethalometer housing allows ambient air to flow through the collection area of the filter so that aerosol particles can be collected on the filter. A rotating disk with an opening therethrough allows light for the light source to pass alternately through the two light paths. The voltage output of the detector is applied to a VCO and the VCO pulses for light transmission separately through the two light paths, are counted and compared to determine the absorption coefficient of the collected aerosol particles. 5 figs.

Phototropin 1 and dim-blue light modulate the red light de-etiolation response.

PubMed

Wang, Yihai; M Folta, Kevin

2014-01-01

Light signals regulate seedling morphological changes during de-etiolation through the coordinated actions of multiple light-sensing pathways. Previously we have shown that red-light-induced hypocotyl growth inhibition can be reversed by addition of dim blue light through the action of phototropin 1 (phot1). Here we further examine the fluence-rate relationships of this blue light effect in short-term (hours) and long-term (days) hypocotyl growth assays. The red stem-growth inhibition and blue promotion is a low-fluence rate response, and blue light delays or attenuates both the red light and far-red light responses. These de-etiolation responses include blue light reversal of red or far-red induced apical hook opening. This response also requires phot1. Cryptochromes (cry1 and cry2) are activated by higher blue light fluence-rates and override phot1's influence on hypocotyl growth promotion. Exogenous application of auxin transport inhibitor naphthylphthalamic acid abolished the blue light stem growth promotion in both hypocotyl growth and hook opening. Results from the genetic tests of this blue light effect in auxin transporter mutants, as well as phytochrome kinase substrate mutants indicated that aux1 may play a role in blue light reversal of red light response. Together, the phot1-mediated adjustment of phytochrome-regulated photomorphogenic events is most robust in dim blue light conditions and is likely modulated by auxin transport through its transporters.

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

PubMed

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.

Assessment of the actual light dose in photodynamic therapy.

PubMed

Schaberle, Fabio A

2018-06-09

Photodynamic therapy (PDT) initiates with the absorption of light, which depends on the spectral overlap between the light source emission and the photosensitizer absorption, resulting in the number of photons absorbed, the key parameter starting PDT processes. Most papers report light doses regardless if the light is only partially absorbed or shifted relatively to the absorption peak, misleading the actual light dose value and not allowing quantitative comparisons between photosensitizers and light sources. In this manuscript a method is presented to calculate the actual light dose delivered by any light source for a given photosensitizer. This method allows comparing light doses delivered for any combination of light source (broad or narrow band or daylight) and photosensitizer. Copyright © 2018. Published by Elsevier B.V.

Long-distance transmission of light in a scintillator-based radiation detector

DOEpatents

Dowell, Jonathan L.; Talbott, Dale V.; Hehlen, Markus P.

2017-07-11

Scintillator-based radiation detectors capable of transmitting light indicating the presence of radiation for long distances are disclosed herein. A radiation detector can include a scintillator layer and a light-guide layer. The scintillator layer is configured to produce light upon receiving incident radiation. The light-guide layer is configured to receive light produced by the scintillator layer and either propagate the received light through the radiation detector or absorb the received light and emit light, through fluorescence, that is propagated through the radiation detector. A radiation detector can also include an outer layer partially surrounding the scintillator layer and light-guide layer. The index of refraction of the light-guide layer can be greater than the index of refraction of adjacent layers.

Light-Mediated Hormonal Regulation of Plant Growth and Development.

PubMed

de Wit, Mieke; Galvão, Vinicius Costa; Fankhauser, Christian

2016-04-29

Light is crucial for plant life, and perception of the light environment dictates plant growth, morphology, and developmental changes. Such adjustments in growth and development in response to light conditions are often established through changes in hormone levels and signaling. This review discusses examples of light-regulated processes throughout a plant's life cycle for which it is known how light signals lead to hormonal regulation. Light acts as an important developmental switch in germination, photomorphogenesis, and transition to flowering, and light cues are essential to ensure light capture through architectural changes during phototropism and the shade avoidance response. In describing well-established links between light perception and hormonal changes, we aim to give insight into the mechanisms that enable plants to thrive in variable light environments.

Imaging spectrometer wide field catadioptric design

DOEpatents

Chrisp,; Michael, P [Danville, CA

2008-08-19

A wide field catadioptric imaging spectrometer with an immersive diffraction grating that compensates optical distortions. The catadioptric design has zero Petzval field curvature. The imaging spectrometer comprises an entrance slit for transmitting light, a system with a catadioptric lens and a dioptric lens for receiving the light and directing the light, an immersion grating, and a detector array. The entrance slit, the system for receiving the light, the immersion grating, and the detector array are positioned wherein the entrance slit transmits light to the system for receiving the light and the system for receiving the light directs the light to the immersion grating and the immersion grating receives the light and directs the light through the system for receiving the light to the detector array.

Status of Solid State Lighting Product Development and Future Trends for General Illumination.

PubMed

Katona, Thomas M; Pattison, P Morgan; Paolini, Steve

2016-06-07

After decades of research and development on fabrication of efficient light-emitting diodes (LEDs) throughout the visible spectrum, LED-based lighting has reached unparalleled performance with respect to energy efficiency and has become the light source for virtually all new lighting products being designed today. The development of the core light sources and their subsequent integration into lighting systems continue to present unique challenges and opportunities for product designers. We review these systems and the current development status, as well as provide context for the trends in solid state lighting that are leading to the development of value-added lighting solutions that extend the domain of lighting beyond light generation, into fields as diverse as communications, healthcare, and agricultural production.

14 CFR 23.1385 - Position light system installation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Position light system installation. 23.1385... Lights § 23.1385 Position light system installation. (a) General. Each part of each position light system... requirements of §§ 23.1387 through 23.1397. (b) Left and right position lights. Left and right position lights...

49 CFR 234.219 - Gate arm lights and light cable.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Gate arm lights and light cable. 234.219 Section... Maintenance, Inspection, and Testing Maintenance Standards § 234.219 Gate arm lights and light cable. Each gate arm light shall be maintained in such condition to be properly visible to approaching highway...

14 CFR 23.1385 - Position light system installation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Position light system installation. 23.1385... Lights § 23.1385 Position light system installation. (a) General. Each part of each position light system... requirements of §§ 23.1387 through 23.1397. (b) Left and right position lights. Left and right position lights...

14 CFR 23.1385 - Position light system installation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Position light system installation. 23.1385... Lights § 23.1385 Position light system installation. (a) General. Each part of each position light system... requirements of §§ 23.1387 through 23.1397. (b) Left and right position lights. Left and right position lights...

14 CFR 23.1385 - Position light system installation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Position light system installation. 23.1385... Lights § 23.1385 Position light system installation. (a) General. Each part of each position light system... requirements of §§ 23.1387 through 23.1397. (b) Left and right position lights. Left and right position lights...

49 CFR 234.219 - Gate arm lights and light cable.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Gate arm lights and light cable. 234.219 Section... Maintenance, Inspection, and Testing Maintenance Standards § 234.219 Gate arm lights and light cable. Each gate arm light shall be maintained in such condition to be properly visible to approaching highway...

Ellipsoidal cell flow system

DOEpatents

Salzman, Gary C.; Mullaney, Paul F.

1976-01-01

The disclosure relates to a system incorporating an ellipsoidal flow chamber having light reflective walls for low level light detection in practicing cellular analysis. The system increases signal-to-noise ratio by a factor of ten over prior art systems. In operation, laser light passes through the primary focus of the ellipsoid. A controlled flow of cells simultaneously passes through this focus so that the laser light impinges on the cells and is modulated by the cells. The reflective walls of the ellipsoid reflect the cell-modulated light to the secondary focus of the ellipsoid. A tapered light guide at the secondary focus picks up a substantial portion of modulated reflective light and directs it onto a light detector to produce a signal. The signal is processed to obtain the intensity distribution of the modulated light and hence sought after characteristics of the cells. In addition, cells may be dyed so as to fluoresce in response to the laser light and their fluorescence may be processed as cell-modulated light above described. A light discriminating filter would be used to distinguish reflected modulated laser light from reflected fluorescent light.

Seeing the Light: The Roles of Red- and Blue-Light Sensing in Plant Microbes.

PubMed

Beattie, Gwyn A; Hatfield, Bridget M; Dong, Haili; McGrane, Regina S

2018-05-16

Plants collect, concentrate, and conduct light throughout their tissues, thus enhancing light availability to their resident microbes. This review explores the role of photosensing in the biology of plant-associated bacteria and fungi, including the molecular mechanisms of red-light sensing by phytochromes and blue-light sensing by LOV (light-oxygen-voltage)-domain proteins in these microbes. Bacteriophytochromes function as major drivers of the bacterial transcriptome and mediate light-regulated suppression of virulence, motility, and conjugation in some phytopathogens and light-regulated induction of the photosynthetic apparatus in a stem-nodulating symbiont. Bacterial LOV proteins also influence light-mediated changes in both symbiotic and pathogenic phenotypes. Although red-light sensing by fungal phytopathogens is poorly understood, fungal LOV proteins contribute to blue-light regulation of traits, including asexual development and virulence. Collectively, these studies highlight that plant microbes have evolved to exploit light cues and that light sensing is often coupled with sensing other environmental signals. Expected final online publication date for the Annual Review of Phytopathology Volume 56 is August 25, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Association between light-to-dark changes in angle width and iris parameters in light, dark and changes from light-to-dark conditions.

PubMed

Lee, Roland Y; Lin, Shuai-Chun; Chen, Rebecca I; Barbosa, Diego T; Lin, Shan C

2016-09-01

To evaluate the association between light-to-dark changes in angle width parameters and iris parameters in light, dark and changes from light-to-dark conditions. In this prospective, cross-sectional study, anterior segment optical coherence tomography images, obtained under light and dark conditions, were analysed to determine angle opening distance measured at 500 μm from the scleral spur (AOD500), trabecular-iris space area at 500 μm from the scleral spur (TISA500), iris thickness measured at 750 μm from the scleral spur (IT750), iris thickness measured at 2000 μm from the scleral spur (IT2000), iris area (IArea) and pupil diameter (PD). Multivariable linear mixed-effect regression models were used to evaluate the association between light-to-dark changes in angle width parameters (AOD500, TISA500) and iris parameters (IT750, IT2000, IArea, PD) in light, dark and changes from light-to-dark conditions. 534 eyes from 314 non-glaucomatous subjects were analysed. IT750, IT2000, IArea and PD in light conditions were significantly associated with light-to-dark changes in AOD500 (p<0.05). IT750, IT2000 and IArea in light conditions were significantly associated with light-to-dark changes in TISA500 (p<0.05). IT750 in dark conditions was significantly associated with light-to-dark changes in AOD500 and TISA500 (p<0.05). Light-to-dark changes in IT2000, IArea and PD were significantly associated with light-to-dark changes in AOD500 (p<0.05). Light-to-dark changes in IArea were significantly associated with light-to-dark changes in TISA500 (p<0.05). Evaluation of iris parameters in light, dark and changes from light-to-dark conditions demonstrated that IT750, IT2000, IArea and PD in light conditions are significant predictors of light-to-dark changes in angle width. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Illuminating system and method for specialized and decorative lighting using liquid light guides

DOEpatents

Zorn, C.J.; Kross, B.J.; Majewski, S.; Wojcik, R.F.

1998-08-25

The present invention comprises an illumination system for specialized decorative lighting including a light source, a flexible plastic tube sheath for distributing the light to a remote location, a transparent liquid core filling the tube that has an index of refraction greater than that of the plastic tube and an arrangement where light coupled from the light source is caused to leak from the liquid light guide at desired locations for the purposes of specialized lighting, such as underwater illumination in swimming pools. 5 figs.

Illuminating system and method for specialized and decorative lighting using liquid light guides

DOEpatents

Zorn, Carl J.; Kross, Brian J.; Majewski, Stanislaw; Wojcik, Randolph F.

1998-01-01

The present invention comprises an illumination system for specialized decorative lighting including a light source, a flexible plastic tube sheath for distributing the light to a remote location, a transparent liquid core filling the tube that has an index of refraction greater than that of the plastic tube and an arrangement where light coupled from the light source is caused to leak from the liquid light guide at desired locations for the purposes of specialized lighting, such as underwater illumination in swimming pools.

Outdoor Lighting Ordinances

NASA Astrophysics Data System (ADS)

Davis, S.

2004-05-01

A principal means to prevent poor exterior lighting practices is a lighting control ordinance. It is an enforceable legal restriction on specific lighting practices that are deemed unacceptable by the government body having jurisdiction. Outdoor lighting codes have proven to be effective at reducing polluting and trespassing light. A well written exterior lighting code will permit all forms of necessary illumination at reasonable intensities, but will demand shielding and other measures to prevent trespass and light pollution. A good code will also apply to all forms of outdoor lighting, including streets, highways, and exterior signs, as well as the lighting on dwellings, commercial and industrial buildings and building sites. A good code can make exceptions for special uses, provided it complies with an effective standard. The IDA Model Lighting Ordinance is a response to these requests. It is intended as an aid to communities that are seeking to take control of their outdoor lighting, to "take back the night" that is being lost to careless and excessive use of night lighting.

A method for improving the light intensity distribution in dental light-curing units.

PubMed

Arikawa, Hiroyuki; Takahashi, Hideo; Minesaki, Yoshito; Muraguchi, Kouichi; Matsuyama, Takashi; Kanie, Takahito; Ban, Seiji

2011-01-01

A method for improving the uniformity of the radiation light from dental light-curing units (LCUs), and the effect on the polymerization of light-activated composite resin are investigated. Quartz-tungsten halogen, plasma-arc, and light-emitting diode LCUs were used, and additional optical elements such as a mixing tube and diffusing screen were employed to reduce the inhomogeneity of the radiation light. The distribution of the light intensity from the light guide tip was measured across the guide tip, as well as the distribution of the surface hardness of the light-activated resin emitted with the LCUs. Although the additional optical elements caused 13.2-25.9% attenuation of the light intensity, the uniformity of the light intensity of the LCUs was significantly improved in the modified LCUs, and the uniformity of the surface hardness of the resin was also improved. Our results indicate that the addition of optical elements to the LCU may be a simple and effective method for reducing inhomogeneity in radiation light from the LCUs.

Manipulation of light wavelength at appropriate growth stage to enhance biomass productivity and fatty acid methyl ester yield using Chlorella vulgaris.

PubMed

Kim, Dae Geun; Lee, Changsu; Park, Seung-Moon; Choi, Yoon-E

2014-05-01

LEDs light offer several advantages over the conventional lamps, thereby being considered as the optimal light sources for microalgal cultivation. In this study, various light-emitting diodes (LEDs) especially red and blue color with different light wavelengths were employed to explore the effects of light source on phototrophic cultivation of Chlorella vulgaris. Blue light illumination led to significantly increased cell size, whereas red light resulted in small-sized cell with active divisions. Based on the discovery of the effect of light wavelengths on microalgal biology, we then applied appropriate wavelength at different growth stages; blue light was illuminated first and then shifted to red light. By doing so, biomass and lipid productivity of C. vulgaris could be significantly increased, compared to that in the control. These results will shed light on a novel approach using LED light for microalgal biotechnology. Copyright © 2014 Elsevier Ltd. All rights reserved.

Blue light effect on retinal pigment epithelial cells by display devices.

PubMed

Moon, Jiyoung; Yun, Jieun; Yoon, Yeo Dae; Park, Sang-Il; Seo, Young-Jun; Park, Won-Sang; Chu, Hye Yong; Park, Keun Hong; Lee, Myung Yeol; Lee, Chang Woo; Oh, Soo Jin; Kwak, Young-Shin; Jang, Young Pyo; Kang, Jong Soon

2017-05-22

Blue light has high photochemical energy and induces cell apoptosis in retinal pigment epithelial cells. Due to its phototoxicity, retinal hazard by blue light stimulation has been well demonstrated using high intensity light sources. However, it has not been studied whether blue light in the displays, emitting low intensity light, such as those used in today's smartphones, monitors, and TVs, also causes apoptosis in retinal pigment epithelial cells. We attempted to examine the blue light effect on human adult retinal epithelial cells using display devices with different blue light wavelength ranges, the peaks of which specifically appear at 449 nm, 458 nm, and 470 nm. When blue light was illuminated on A2E-loaded ARPE-19 cells using these displays, the display with a blue light peak at a shorter wavelength resulted in an increased production of reactive oxygen species (ROS). Moreover, the reduction of cell viability and induction of caspase-3/7 activity were more evident in A2E-loaded ARPE-19 cells after illumination by the display with a blue light peak at a shorter wavelength, especially at 449 nm. Additionally, white light was tested to examine the effect of blue light in a mixed color illumination with red and green lights. Consistent with the results obtained using only blue light, white light illuminated by display devices with a blue light peak at a shorter wavelength also triggered increased cell death and apoptosis compared to that illuminated by display devices with a blue light peak at longer wavelength. These results show that even at the low intensity utilized in the display devices, blue light can induce ROS production and apoptosis in retinal cells. Our results also suggest that the blue light hazard of display devices might be highly reduced if the display devices contain less short wavelength blue light.

Impact of different colours of artificial light at night on melatonin rhythm and gene expression of gonadotropins in European perch.

PubMed

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

2016-02-01

The distribution and intensity of artificial light at night, commonly referred to as light pollution, is consequently rising and progressively also ecological implications come to light. Low intensity light is known to suppress nocturnal melatonin production in several fish species. This study aims to examine the least suppressive light colour for melatonin excreted into the holding water and the influence of different light qualities and quantities in the night on gene expression of gonadotropins in fish. European perch (Perca fluviatilis) were exposed to light of different wavelengths during the night (blue, green, and red). Melatonin concentrations were measured from water samples every 3h during a 24h period. Gene expression of gonadotropins was measured in perch exposed to different light colours and was additionally examined for perch subjected to different intensities of white light (0 lx, 1 lx, 10 lx, 100 lx) during the night. All different light colours caused a significant drop of melatonin concentration; however, blue light was least suppressive. Gene expression of gonadotropins was not influenced by nocturnal light of different light colours, but in female perch gonadotropin expression was significantly reduced by white light already at the lowest level (1 lx). We conclude that artificial light with shorter wavelengths at night is less effective in disturbing biological rhythms of perch than longer wavelengths, coinciding with the light situation in freshwater habitats inhabited by perch. Different light colours in the night showed no significant effect on gonadotropin expression, but white light in the night can disturb reproductive traits already at very low light intensities. These findings indicate that light pollution has not only the potential to disturb the melatonin cycle but also the reproductive rhythm and may therefore have implications on whole species communities. Copyright © 2015 Elsevier B.V. All rights reserved.

Flexible liquid core light guide with focusing and light shaping attachments

DOEpatents

Kross, B.J.; Majewski, S.; Zorn, C.J.; Majewski, L.A.

1997-11-04

A liquid light guide system for ultraviolet light is disclosed that has a light shaping arrangement for the emitted light, a stable liquid core and sheath and reliable and effective end closures. 12 figs.

Continuous background light significantly increases flashing-light enhancement of photosynthesis and growth of microalgae.

PubMed

Abu-Ghosh, Said; Fixler, Dror; Dubinsky, Zvy; Iluz, David

2015-01-01

Under specific conditions, flashing light enhances the photosynthesis rate in comparison to continuous illumination. Here we show that a combination of flashing light and continuous background light with the same integrated photon dose as continuous or flashing light alone can be used to significantly enhance photosynthesis and increase microalgae growth. To test this hypothesis, the green microalga Dunaliella salina was exposed to three different light regimes: continuous light, flashing light, and concomitant application of both. Algal growth was compared under three different integrated light quantities; low, intermediate, and moderately high. Under the combined light regime, there was a substantial increase in all algal growth parameters, with an enhanced photosynthesis rate, within 3days. Our strategy demonstrates a hitherto undescribed significant increase in photosynthesis and algal growth rates, which is beyond the increase by flashing light alone. Copyright © 2015 Elsevier Ltd. All rights reserved.

Lethal effects of short-wavelength visible light on insects.

PubMed

Hori, Masatoshi; Shibuya, Kazuki; Sato, Mitsunari; Saito, Yoshino

2014-12-09

We investigated the lethal effects of visible light on insects by using light-emitting diodes (LEDs). The toxic effects of ultraviolet (UV) light, particularly shortwave (i.e., UVB and UVC) light, on organisms are well known. However, the effects of irradiation with visible light remain unclear, although shorter wavelengths are known to be more lethal. Irradiation with visible light is not thought to cause mortality in complex animals including insects. Here, however, we found that irradiation with short-wavelength visible (blue) light killed eggs, larvae, pupae, and adults of Drosophila melanogaster. Blue light was also lethal to mosquitoes and flour beetles, but the effective wavelength at which mortality occurred differed among the insect species. Our findings suggest that highly toxic wavelengths of visible light are species-specific in insects, and that shorter wavelengths are not always more toxic. For some animals, such as insects, blue light is more harmful than UV light.

Light field imaging and application analysis in THz

NASA Astrophysics Data System (ADS)

Zhang, Hongfei; Su, Bo; He, Jingsuo; Zhang, Cong; Wu, Yaxiong; Zhang, Shengbo; Zhang, Cunlin

2018-01-01

The light field includes the direction information and location information. Light field imaging can capture the whole light field by single exposure. The four-dimensional light field function model represented by two-plane parameter, which is proposed by Levoy, is adopted in the light field. Acquisition of light field is based on the microlens array, camera array and the mask. We calculate the dates of light-field to synthetize light field image. The processing techniques of light field data include technology of refocusing rendering, technology of synthetic aperture and technology of microscopic imaging. Introducing the technology of light field imaging into THz, the efficiency of 3D imaging is higher than that of conventional THz 3D imaging technology. The advantages compared with visible light field imaging include large depth of field, wide dynamic range and true three-dimensional. It has broad application prospects.

Lethal effects of short-wavelength visible light on insects

NASA Astrophysics Data System (ADS)

Hori, Masatoshi; Shibuya, Kazuki; Sato, Mitsunari; Saito, Yoshino

2014-12-01

We investigated the lethal effects of visible light on insects by using light-emitting diodes (LEDs). The toxic effects of ultraviolet (UV) light, particularly shortwave (i.e., UVB and UVC) light, on organisms are well known. However, the effects of irradiation with visible light remain unclear, although shorter wavelengths are known to be more lethal. Irradiation with visible light is not thought to cause mortality in complex animals including insects. Here, however, we found that irradiation with short-wavelength visible (blue) light killed eggs, larvae, pupae, and adults of Drosophila melanogaster. Blue light was also lethal to mosquitoes and flour beetles, but the effective wavelength at which mortality occurred differed among the insect species. Our findings suggest that highly toxic wavelengths of visible light are species-specific in insects, and that shorter wavelengths are not always more toxic. For some animals, such as insects, blue light is more harmful than UV light.

Blue light versus red light for photodynamic therapy of basal cell carcinoma in patients with Gorlin syndrome: A bilaterally controlled comparison study.

PubMed

Maytin, Edward V; Kaw, Urvashi; Ilyas, Muneeb; Mack, Judith A; Hu, Bo

2018-06-01

Photodynamic therapy (PDT) is a non-scarring alternative for treating basal cell carcinoma (BCC) in patients with Basal Cell Nevus Syndrome (BCNS), also known as Gorlin syndrome. In Europe, red light (635 nm) is the predominant source for PDT, whereas in the United States blue light (400 nm) is more widely available. The objective of this study was to conduct a head-to-head comparison of blue light and red light PDT in the same BCNS patients. In a pilot study of three patients with 141 BCC lesions, 5-aminolevulinate (20% solution) was applied to all tumors. After 4 h, half of the tumors were illuminated with blue light and the remainder with red light. To ensure safety while treating this many tumors simultaneously, light doses were escalated gradually. Six treatments were administered in three biweekly sessions over 4 months, with a final evaluation at 6 months. Tumor status was documented with high-resolution photographs. Persistent lesions were biopsied at 6 months. Clearance rates after blue light (98%) were slightly better than after red light (93%), with blue light shown to be statistically non-inferior to red light. Eight suspicious lesions were biopsied, 5 after red light (5/5 were BCC) and 3 after blue light (1 was BCC). Blue light PDT was reportedly less painful. Blue light and red light PDT appear to be equally safe and perhaps equally effective for treating BCC tumors in BCNS patients. Further studies to evaluate long-term clearance after blue light PDT are needed. Copyright © 2018 Elsevier B.V. All rights reserved.

The ecological impacts of nighttime light pollution: a mechanistic appraisal.

PubMed

Gaston, Kevin J; Bennie, Jonathan; Davies, Thomas W; Hopkins, John

2013-11-01

The ecological impacts of nighttime light pollution have been a longstanding source of concern, accentuated by realized and projected growth in electrical lighting. As human communities and lighting technologies develop, artificial light increasingly modifies natural light regimes by encroaching on dark refuges in space, in time, and across wavelengths. A wide variety of ecological implications of artificial light have been identified. However, the primary research to date is largely focused on the disruptive influence of nighttime light on higher vertebrates, and while comprehensive reviews have been compiled along taxonomic lines and within specific research domains, the subject is in need of synthesis within a common mechanistic framework. Here we propose such a framework that focuses on the cross-factoring of the ways in which artificial lighting alters natural light regimes (spatially, temporally, and spectrally), and the ways in which light influences biological systems, particularly the distinction between light as a resource and light as an information source. We review the evidence for each of the combinations of this cross-factoring. As artificial lighting alters natural patterns of light in space, time and across wavelengths, natural patterns of resource use and information flows may be disrupted, with downstream effects to the structure and function of ecosystems. This review highlights: (i) the potential influence of nighttime lighting at all levels of biological organisation (from cell to ecosystem); (ii) the significant impact that even low levels of nighttime light pollution can have; and (iii) the existence of major research gaps, particularly in terms of the impacts of light at population and ecosystem levels, identification of intensity thresholds, and the spatial extent of impacts in the vicinity of artificial lights. © 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.

Green light drives leaf photosynthesis more efficiently than red light in strong white light: revisiting the enigmatic question of why leaves are green.

PubMed

Terashima, Ichiro; Fujita, Takashi; Inoue, Takeshi; Chow, Wah Soon; Oguchi, Riichi

2009-04-01

The literature and our present examinations indicate that the intra-leaf light absorption profile is in most cases steeper than the photosynthetic capacity profile. In strong white light, therefore, the quantum yield of photosynthesis would be lower in the upper chloroplasts, located near the illuminated surface, than that in the lower chloroplasts. Because green light can penetrate further into the leaf than red or blue light, in strong white light, any additional green light absorbed by the lower chloroplasts would increase leaf photosynthesis to a greater extent than would additional red or blue light. Based on the assessment of effects of the additional monochromatic light on leaf photosynthesis, we developed the differential quantum yield method that quantifies efficiency of any monochromatic light in white light. Application of this method to sunflower leaves clearly showed that, in moderate to strong white light, green light drove photosynthesis more effectively than red light. The green leaf should have a considerable volume of chloroplasts to accommodate the inefficient carboxylation enzyme, Rubisco, and deliver appropriate light to all the chloroplasts. By using chlorophylls that absorb green light weakly, modifying mesophyll structure and adjusting the Rubisco/chlorophyll ratio, the leaf appears to satisfy two somewhat conflicting requirements: to increase the absorptance of photosynthetically active radiation, and to drive photosynthesis efficiently in all the chloroplasts. We also discuss some serious problems that are caused by neglecting these intra-leaf profiles when estimating whole leaf electron transport rates and assessing photoinhibition by fluorescence techniques.

Effect of Red and Blue Light on Anthocyanin Accumulation and Differential Gene Expression in Strawberry (Fragaria × ananassa).

PubMed

Zhang, Yunting; Jiang, Leiyu; Li, Yali; Chen, Qing; Ye, Yuntian; Zhang, Yong; Luo, Ya; Sun, Bo; Wang, Xiaorong; Tang, Haoru

2018-04-03

Light conditions can cause quantitative and qualitative changes in anthocyanin. However, little is known about the underlying mechanism of light quality-regulated anthocyanin accumulation in fruits. In this study, light-emitting diodes (LEDs) were applied to explore the effect of red and blue light on strawberry coloration. The results showed contents of total anthocyanins (TA), pelargonidin 3-glucoside (Pg3G) and pelargonidin 3-malonylglucoside (Pg3MG) significantly increased after blue and red light treatment. Pg3G was the major anthocyanin component in strawberry fruits, accounting for more than 80% of TA, whereas Pg3MG accounted for a smaller proportion. Comparative transcriptome analysis was conducted using libraries from the treated strawberries. A total of 1402, 5034, and 3764 differentially-expressed genes (DEGs) were identified in three pairwise comparisons (red light versus white light, RL-VS-WL; blue light versus white light, BL-VS-WL; blue light versus red light, BL-VS-RL), respectively. Photoreceptors and light transduction components remained dynamic to up-regulate the expression of regulatory factors and structural genes related to anthocyanin biosynthesis under red and white light, whereas most genes had low expression levels that were not consistent with the highest total anthocyanin content under blue light. Therefore, the results indicated that light was an essential environmental factor for anthocyanin biosynthesis before the anthocyanin concentration reached saturation in strawberry fruits, and blue light could quickly stimulate the accumulation of anthocyanin in the fruit. In addition, red light might contribute to the synthesis of proanthocyanidins by inducing LAR and ANR .

Daytime light exposure: effects on biomarkers, measures of alertness, and performance.

PubMed

Sahin, Levent; Wood, Brittany M; Plitnick, Barbara; Figueiro, Mariana G

2014-11-01

Light can elicit an alerting response in humans, independent from acute melatonin suppression. Recent studies have shown that red light significantly increases daytime and nighttime alertness. The main goal of the present study was to further investigate the effects of daytime light exposure on performance, biomarkers and measures of alertness. It was hypothesized that, compared to remaining in dim light, daytime exposure to narrowband long-wavelength (red) light or polychromatic (2568K) light would induce greater alertness and shorter response times. Thirteen subjects experienced three lighting conditions: dim light (<5lux), red light (λmax=631nm, 213lux, 1.1W/m(2)), and white light (2568K, 361lux, 1.1W/m(2)). The presentation order of the lighting conditions was counterbalanced across the participants and each participant saw a different lighting condition each week. Our results demonstrate, for the first time, that red light can increase short-term performance as shown by the significant (p<0.05) reduced response time and higher throughput in performance tests during the daytime. There was a significant decrease (p<0.05) in alpha power and alpha-theta power after exposure to the white light, but this alerting effect did not translate to better performance. Alpha power was significantly reduced after red light exposure in the middle of the afternoon. There was no significant effect of light on cortisol and alpha amylase. The present results suggest that red light can be used to increase daytime performance. Copyright © 2014 Elsevier B.V. All rights reserved.

33 CFR 118.80 - Lights on bascule bridges.

Code of Federal Regulations, 2010 CFR

2010-07-01

... LIGHTING AND OTHER SIGNALS § 118.80 Lights on bascule bridges. (a) Lift span lights. Each lift span of... which shows for all other positions of the lift span. Each red and each green light shall show through a... lift span navigation lights are made, existing lights may show through a horizontal arc of less than...

33 CFR 118.80 - Lights on bascule bridges.

Code of Federal Regulations, 2011 CFR

2011-07-01

... LIGHTING AND OTHER SIGNALS § 118.80 Lights on bascule bridges. (a) Lift span lights. Each lift span of... which shows for all other positions of the lift span. Each red and each green light shall show through a... lift span navigation lights are made, existing lights may show through a horizontal arc of less than...

Provide Natural Light | Efficient Windows Collaborative

Science.gov Websites

illumination when desired. Providing Balanced Lighting A balance of light is important both for visual comfort protected from excessive light levels. The balance of light in a space depends on the overall number and furnishings. An improved balance of light can be created by providing light from at least two directions, such

Cost and energy-efficient (LED, induction and plasma) roadway lighting.

DOT National Transportation Integrated Search

2013-11-01

There is an increasing interest in using new lighting technologies such as light emitting diode (LED), Induction, and Plasma light sources : in roadway lighting. The most commonly claimed benefits of the new lighting systems include increased reliabi...

Measures of Light in Studies on Light-Driven Plant Plasticity in Artificial Environments

PubMed Central

Niinemets, Ülo; Keenan, Trevor F.

2012-01-01

Within-canopy variation in light results in profound canopy profiles in foliage structural, chemical, and physiological traits. Studies on within-canopy variations in key foliage traits are often conducted in artificial environments, including growth chambers with only artificial light, and greenhouses with and without supplemental light. Canopy patterns in these systems are considered to be representative to outdoor conditions, but in experiments with artificial and supplemental lighting, the intensity of artificial light strongly deceases with the distance from the light source, and natural light intensity in greenhouses is less than outdoors due to limited transmittance of enclosure walls. The implications of such changes in radiation conditions on canopy patterns of foliage traits have not yet been analyzed. We developed model-based methods for retrospective estimation of distance vs. light intensity relationships, for separation of the share of artificial and natural light in experiments with combined light and for estimation of average enclosure transmittance, and estimated daily integrated light at the time of sampling (Qint,C), at foliage formation (Qint,G), and during foliage lifetime (Qint,av). The implications of artificial light environments were analyzed for altogether 25 studies providing information on within-canopy gradients of key foliage traits for 70 species × treatment combinations. Across the studies with artificial light, Qint,G for leaves formed at different heights in the canopy varied from 1.8- to 6.4-fold due to changing the distance between light source and growing plants. In experiments with combined lighting, the share of natural light at the top of the plants varied threefold, and the share of natural light strongly increased with increasing depth in the canopy. Foliage nitrogen content was most strongly associated with Qint,G, but photosynthetic capacity with Qint,C, emphasizing the importance of explicit description of light environment during foliage lifetime. The reported and estimated transmittances of enclosures varied between 0.27 and 0.85, and lack of consideration of the reduction of light compared with outdoor conditions resulted in major underestimation of foliage plasticity to light. The study emphasizes that plant trait vs. light relationships in artificial systems are not directly comparable to natural environments unless modifications in lighting conditions in artificial environments are taken into account. PMID:22822407

Determination of the Acceptable Ambient Light Exposure during Drug Product Manufacturing for Long Term Stability of Monoclonal Antibodies.

PubMed

Luis, Lin M; Hu, Yuzhe; Zamiri, Camellia; Sreedhara, Alavattam

2018-05-31

Monoclonal antibodies (mAbs) are exposed to light during drug product (DP) manufacturing and the acceptable levels of light exposure needs to be determined based on the impact on product quality. In this study, a mild and more representative light model consisting of ambient light instead of stress light as prescribed by ICH Q1B was used to evaluate the impact of light exposure on mAb DP quality. The immediate effect of ambient light exposure on protein drug product quality was determined to be dependent on the amount of light exposure rather than light intensity (up to 5000 lux). The impact on quality of mAbs is product specific due to their differences in light sensitivity, in which mAb II shows larger increases in IEC basic variants and larger decreases in SEC monomer when compared to mAb I after 0.24 million lux hours of light exposure. The acceptable ambient light exposure for mAb II drug product manufacturing was determined to be 0.13 million lux hours, in which no impact on product quality was observed after the short-term light exposure. Additionally, real-time storage (5°C) of the DP after the prescribed ambient light exposure showed no impact to various product quality attributes. The light model used in this study is capable of determining the acceptable amount of ambient light exposure for mAbs, especially during DP manufacturing processes. Copyright © 2018, Parenteral Drug Association.

The Influence of Low Intensities of Light Pollution on Bat Communities in a Semi-Natural Context

PubMed Central

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. PMID:25360638

Secondary and sucrose metabolism regulated by different light quality combinations involved in melon tolerance to powdery mildew.

PubMed

Jing, Xin; Wang, Hui; Gong, Biao; Liu, Shiqi; Wei, Min; Ai, Xizhen; Li, Yan; Shi, Qinghua

2018-03-01

We evaluated the effect of different light combinations on powdery mildew resistance and growth of melon seedlings. Light-emitting diodes were used as the light source and there were five light combinations: white light (420-680 nm); blue light (460 nm); red light (635 nm); RB31 (ratio of red and blue light, 3: 1); and RB71 (ratio of red and blue light, 7: 1). Compared with other treatments, blue light significantly decreased the incidence of powdery mildew in leaves of melon seedlings. Under blue light, H 2 O 2 showed higher accumulation, and the content of phenolics, flavonoid and tannins, as well as expression of the genes involved in synthesis of these substances, significantly increased compared with other treatments before and after infection. Lignin content and expression of the genes related to its synthesis were also induced by blue light before infection. Melon irradiated with RB31 light showed the best growth parameters. Compared with white light, red light and RB71, RB31 showed higher accumulation of lignin and lower incidence of powdery mildew. We conclude that blue light increases melon resistance to powdery mildew, which is dependent on the induction of secondary metabolism that may be related to H 2 O 2 accumulation before infection. Induction of tolerance of melon seeds to powdery mildew by RB31 is due to higher levels of sucrose metabolism and accumulation of lignin. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Light use efficiency for vegetables production in protected and indoor environments

NASA Astrophysics Data System (ADS)

Cocetta, Giacomo; Casciani, Daria; Bulgari, Roberta; Musante, Fulvio; Kołton, Anna; Rossi, Maurizio; Ferrante, Antonio

2017-01-01

In recent years, there is a growing interest for vegetables production in indoor or disadvantaged climatic zones by using greenhouses. The main problem of crop growing indoor or in environment with limited light availability is the correct choice of light source and the quality of lighting spectrum. In greenhouse and indoor cultivations, plant density is higher than in the open field and plants have to compete for light and nutrients. Nowadays, advanced systems for indoor horticulture use light emitting diodes (LED) for improving crop growth, enhancing the plant productivity and favouring the best nutritional quality formation. In closed environments, as indoor growing modules, the lighting system represents the only source of light and its features are fundamental for obtaining the best lighting performances for plant and the most efficient solution. LED lighting engines are more efficient compared to the lighting sources used traditionally in horticulture and allow light spectrum and intensity modulations to enhance the light use efficiency for plants. The lighting distribution and the digital controls are fundamental for tailoring the spectral distribution on each plant in specific moments of its growth and play an important role for optimizing growth and produce high-quality vegetables. LED lights can increase plant growth and yield, but also nutraceutical quality, since some light intensities increase pigments biosynthesis and enhance the antioxidants content of leaves or fruits: in this regards the selection of LED primary light sources in relation to the peaks of the absorbance curve of the plants is important.

Phototropin 1 and dim-blue light modulate the red light de-etiolation response

PubMed Central

Wang, Yihai; M Folta, Kevin

2014-01-01

Light signals regulate seedling morphological changes during de-etiolation through the coordinated actions of multiple light-sensing pathways. Previously we have shown that red-light-induced hypocotyl growth inhibition can be reversed by addition of dim blue light through the action of phototropin 1 (phot1). Here we further examine the fluence-rate relationships of this blue light effect in short-term (hours) and long-term (days) hypocotyl growth assays. The red stem-growth inhibition and blue promotion is a low-fluence rate response, and blue light delays or attenuates both the red light and far-red light responses. These de-etiolation responses include blue light reversal of red or far-red induced apical hook opening. This response also requires phot1. Cryptochromes (cry1 and cry2) are activated by higher blue light fluence-rates and override phot1's influence on hypocotyl growth promotion. Exogenous application of auxin transport inhibitor naphthylphthalamic acid abolished the blue light stem growth promotion in both hypocotyl growth and hook opening. Results from the genetic tests of this blue light effect in auxin transporter mutants, as well as phytochrome kinase substrate mutants indicated that aux1 may play a role in blue light reversal of red light response. Together, the phot1-mediated adjustment of phytochrome-regulated photomorphogenic events is most robust in dim blue light conditions and is likely modulated by auxin transport through its transporters. PMID:25482790

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

PubMed

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.

[The dangers of blue light: True story!].

PubMed

Renard, G; Leid, J

2016-05-01

The dangers of the blue light are the object of numerous publications, for both the scientific community and the general public. The new prolific development of light sources emitting potentially toxic blue light (415-455nm) ranges from LED (Light Emitting Diodes) lamps for interior lighting to television screens, computers, digital tablets and smartphones using OLED (Organic Light Emitting Diode) or AMOLED (Active-Matrix Organic Light Emitting Diode) technology. First we will review some technical terms and the main characteristics of light perceived by the human eye. Then we will discuss scientific proof of the toxicity of blue light to the eye, which may cause cataract or macular degeneration. Analysis of the light spectra of several light sources, from natural light to LED lamps, will allow us to specify even better the dangers related to each light source. LED lamps, whether used as components for interior lighting or screens, are of concern if they are used for extended viewing times and at short distance. While we can protect ourselves from natural blue light by wearing colored glasses which filter out, on both front and back surfaces, the toxic wavelengths, it is more difficult to protect oneself from LED lamps in internal lighting, the use of which should be restricted to "white warmth" lamps (2700K). As far as OLED or AMOLED screens are concerned, the only effective protection consists of using them occasionally and only for a short period of time. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Light collection optics for measuring flux and spectrum from light-emitting devices

DOEpatents

McCord, Mark A.; DiRegolo, Joseph A.; Gluszczak, Michael R.

2016-05-24

Systems and methods for accurately measuring the luminous flux and color (spectra) from light-emitting devices are disclosed. An integrating sphere may be utilized to directly receive a first portion of light emitted by a light-emitting device through an opening defined on the integrating sphere. A light collector may be utilized to collect a second portion of light emitted by the light-emitting device and direct the second portion of light into the integrating sphere through the opening defined on the integrating sphere. A spectrometer may be utilized to measure at least one property of the first portion and the second portion of light received by the integrating sphere.

Light extraction from organic light-emitting diodes for lighting applications by sand-blasting substrates.

PubMed

Chen, Shuming; Kwok, Hoi Sing

2010-01-04

Light extraction from organic light-emitting diodes (OLEDs) by scattering the light is one of the effective methods for large-area lighting applications. In this paper, we present a very simple and cost-effective method to rough the substrates and hence to scatter the light. By simply sand-blasting the edges and back-side surface of the glass substrates, a 20% improvement of forward efficiency has been demonstrated. Moreover, due to scattering effect, a constant color over all viewing angles and uniform light pattern with Lambertian distribution has been obtained. This simple and cost-effective method may be suitable for mass production of large-area OLEDs for lighting applications.

Reasonable use of artificial lighting in building energy saving

NASA Astrophysics Data System (ADS)

Hou, Yuhan

2018-06-01

The architectural light environment is a crucial part of the built environment. Appropriate lighting can not only meet the needs of people's production and life, but also have a positive impact on people's mental state and feelings. Architectural lighting occupies a vital part of building energy consumption. At present, China's lighting electricity consumption has accounted for 12% of the total electricity generated in the country. Promoting lighting energy conservation can play an important role in alleviating energy shortages. This article mainly discusses how to make reasonable use of artificial lighting and choose suitable light sources to reduce the energy consumed by lighting under the condition of satisfying a good architectural light environment.

Optical Sensors Using Stimulated Brillouin Scattering

NASA Technical Reports Server (NTRS)

Christensen, Caleb A (Inventor); Zavriyev, Anton (Inventor)

2017-01-01

A method for enhancing a sensitivity of an optical sensor having an optical cavity counter-propagates beams of pump light within the optical cavity to produce scattered light based on Stimulated Brillouin Scattering (SBS). The properties of the pump light are selected to generate fast-light conditions for the scattered light, such that the scattered light includes counter-propagating beams of fast light. The method prevents the pump light from resonating within the optical cavity, while allowing the scattered light to resonate within the optical cavity. At least portions of the scattered light are interfered outside of the optical cavity to produce a beat note for a measurement of the optical sensor. The disclosed method is particularly applicable to optical gyroscopes.

Lighting recommendations for the Social Security Administration Frank Hagel Federal Building in Richmond CA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rubinstein, Francis M.

Specific recommendations are made to improve the lighting quality and energy efficiency of the lighting system at the Social Security Administration Frank Hagel Building in Richmond, CA. The main recommendation is to replace the recessed fluorescent lighting system in the general office area with indirect lighting. Indirect lighting will improve lighting quality, will provide an energy efficient solution and will be about the same cost as the direct lighting system originally proposed.

Organic light emitting diode with light extracting electrode

DOEpatents

Bhandari, Abhinav; Buhay, Harry

2017-04-18

An organic light emitting diode (10) includes a substrate (20), a first electrode (12), an emissive active stack (14), and a second electrode (18). At least one of the first and second electrodes (12, 18) is a light extracting electrode (26) having a metallic layer (28). The metallic layer (28) includes light scattering features (29) on and/or in the metallic layer (28). The light extracting features (29) increase light extraction from the organic light emitting diode (10).

Refrigerated display case lighting with LEDs

NASA Astrophysics Data System (ADS)

Raghavan, Ramesh; Narendran, Nadarajah

2002-11-01

The rapid development of high brightness light emitting diodes (LEDs) has triggered many applications, especially in the area of display lighting. This paper focuses on the application of white LEDs in refrigerated display cases. The fluorescent lighting presently used in commercial refrigerators is inefficient in the application and also it provides poor lighting for merchandising. A laboratory human factors experiment was conducted to assess the preference for the different lighting systems, namely, fluorescent and LED. Two refrigerated display cases, one with the traditional fluorescent lighting system and the other with a prototype LED lighting system, were placed side-by-side in a laboratory setting. Illuminance measurements made within the two display cases showed that the lighting was more uniform with the LED system compared to the traditional fluorescent system. Sixteen human subjects participated in this study and rated their preference for the two lighting systems. The results show that human subjects strongly preferred the display case with the LED lighting. The authors of this manuscript believe a field study would be greatly beneficial to further confirm these results and to understand the relationship between preference and sales. Considering the luminous efficacy of white LEDs presently available in the marketplace, it is possible to develop a LED based lighting system for commercial refrigerators that is competitive with fluorescent lighting system in terms of energy use. The LED based lighting would provide better lighting than traditional fluorescent lighting.

Combinational light emitting diode-high frequency focused ultrasound treatment for HeLa cell.

PubMed

Choe, Se-Woon; Park, Kitae; Park, Chulwoo; Ryu, Jaemyung; Choi, Hojong

2017-12-01

Light sources such as laser and light emitting diode or ultrasound devices have been widely used for cancer therapy and regenerative medicines, since they are more cost-effective and less harmful than radiation therapy, chemotherapy or magnetic treatment. Compared to laser and low intensity ultrasound techniques, light emitting diode and high frequency focused ultrasound shows enhanced therapeutic effects, especially for small tumors. We propose combinational light emitting diode-high frequency focused ultrasound treatment for human cervical cancer HeLa cells. Individual red, green, and blue light emitting diode light only, high frequency focused ultrasound only, or light emitting diode light combined with high frequency focused ultrasound treatments were applied in order to characterize the responses of HeLa cells. Cell density exposed by blue light emitting diode light combined with high frequency focused ultrasound (2.19 ± 0.58%) was much lower than that of cells exposed by red and green light emitting diode lights (81.71 ± 9.92% and 61.81 ± 4.09%), blue light emitting diode light (11.19 ± 2.51%) or high frequency focused ultrasound only (9.72 ± 1.04%). We believe that the proposed combinational blue light emitting diode-high frequency focused ultrasound treatment could have therapeutic benefits to alleviate cancer cell proliferation.

The Switch from Low-Pressure Sodium to Light Emitting Diodes Does Not Affect Bat Activity at Street Lights

PubMed Central

Rowse, Elizabeth G.; Harris, Stephen; Jones, Gareth

2016-01-01

We used a before-after-control-impact paired design to examine the effects of a switch from low-pressure sodium (LPS) to light emitting diode (LED) street lights on bat activity at twelve sites across southern England. LED lights produce broad spectrum ‘white’ light compared to LPS street lights that emit narrow spectrum, orange light. These spectral differences could influence the abundance of insects at street lights and thereby the activity of the bats that prey on them. Most of the bats flying around the LPS lights were aerial-hawking species, and the species composition of bats remained the same after the switch-over to LED. We found that the switch-over from LPS to LED street lights did not affect the activity (number of bat passes), or the proportion of passes containing feeding buzzes, of those bat species typically found in close proximity to street lights in suburban environments in Britain. This is encouraging from a conservation perspective as many existing street lights are being, or have been, switched to LED before the ecological consequences have been assessed. However, lighting of all spectra studied to date generally has a negative impact on several slow-flying bat species, and LED lights are rarely frequented by these ‘light-intolerant’ bat species. PMID:27008274

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riza, Nabeel Agha; Perez, Frank

A remote temperature sensing system includes a light source selectively producing light at two different wavelengths and a sensor device having an optical path length that varies as a function of temperature. The sensor receives light emitted by the light source and redirects the light along the optical path length. The system also includes a detector receiving redirected light from the sensor device and generating respective signals indicative of respective intensities of received redirected light corresponding to respective wavelengths of light emitted by the light source. The system also includes a processor processing the signals generated by the detector tomore » calculate a temperature of the device.« less

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

PubMed

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.

Study of the Light Received Characteristics of a Plant-Shoot-Light-Condensing System with Simple Leaves or Lobed Leaves

NASA Astrophysics Data System (ADS)

Obara, Shin'ya

Plant shoot configurations evolve so that maximum sunlight may be obtained. The objective of this study is to develop a compact light-condensing system mimicking a plant shoot configuration that is applicable to a light source from a large area. In this paper, the relationship between the position of a light source (the sun) and the rate at which light is absorbed by each leaf was investigated in detail for plant shoot models of a dogwood (simple leaf) and a ginkgo tree (lobed leaf). The rate of light quantum received in each leaf model is reported to an analysis program that uses cross entropy (CE). The analyses showed that the peak amount of light received in the plant-shoot-light-condensing system was during February (vernal equinox) and October (autumnal equinox). Similarly, the rate of light quantum received in each leaf was measured with the CE. The results found that the plant-shoot-light-condensing system that maximizes the amount of light received has differences in the light received in each leaf. Furthermore, the light-condensing characteristics of the ginkgo biloba model are better than the dogwood model. The light-condensing characteristics of a leaf are influenced by the size, a lobe, shape, and the length of the branch.

Aperture lamp

DOEpatents

MacLennan, Donald A.; Turner, Brian P.

2003-01-01

A discharge lamp includes means for containing a light emitting fill, the fill being capable of absorbing light at one wavelength and re-emitting the light at a different wavelength, the light emitted from the fill having a first spectral power distribution in the absence of reflection of light back into the fill; means for exciting the fill to cause the fill to emit light; and means for reflecting some of the light emitted by the fill back into the fill while allowing some light to exit, the exiting light having a second spectral power distribution with proportionately more light in the visible region as compared to the first spectral power distribution, wherein the light re-emitted by the fill is shifted in wavelength with respect to the absorbed light and the magnitude of the shift is in relation to an effective optical path length. Another discharge lamp includes an envelope; a fill which emits light when excited disposed in the envelope; a source of excitation power coupled to the fill to excite the fill and cause the fill to emit light; and a reflective ceramic structure disposed around the envelope and defining an light emitting opening, wherein the structure comprises a sintered body built up directly on the envelope and made from a combination of alumina and silica.

Effects of 530 nm green light on refractive status, melatonin, MT1 receptor, and melanopsin in the guinea pig.

PubMed

Wang, Fei; Zhou, Jiaqi; Lu, Yi; Chu, Renyuan

2011-02-01

To investigate (i) the effect of monochromatic light on inhibiting induction of light-induced melatonin and (ii) the roles of melanopsin and MT1 receptor in light-induced myopia in the guinea pig. Forty-eight guinea pigs were randomly distributed into three treatment groups: white-light (control), green-light (530 nm), and blue-light (480 nm) groups. Levels of pineal gland melatonin were measured twice daily--10:00 a.m. and 10:00 p.m.--10 days after initial light treatment. Thirty additional guinea pigs were also assigned to these groups and treated similarly. For these latter animals, refractive status, ocular length, and vitreous depth were measured before and after light treatment. Eight weeks after light treatment, retinal and sceral levels of melanopsin, melatonin receptor type (MT) 1, and mRNA protein were determined by Western blotting, real-time polymerase chain reaction (RT-PCR), and immunohistochemistry. The level of pineal gland melatonin in the green-light group was significantly higher than that in the blue-light group. Biometric measurements showed that guinea pigs in the green-light group had a somewhat myopic refractive status. Expressions of retinal melanopsin mRNA and protein were significantly higher in the blue-light group and lower in the green-light group when compared to controls. Conversely, expressions of MT1 receptor mRNA and protein in retina and sclera were significantly higher in the green-light group and lower in the blue-light group when compared to controls. Green light appears to suppress induction of melatonin production. In addition, 530 nm of green light is involved in the development of myopia. In the guinea pig, MT1 receptor and melanopsin appear to play roles in the development of myopia induced by 530 nm of light.

75 FR 7426 - Tier 2 Light-Duty Vehicle and Light-Duty Truck Emission Standards and Gasoline Sulfur Control...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-19

... 2060-AI23; 2060-AQ12 Tier 2 Light-Duty Vehicle and Light-Duty Truck Emission Standards and Gasoline... February 10, 2000 (65 FR 6698), EPA published emission standards for light-duty vehicles and light-duty... new passenger cars and light trucks, including pickup trucks, vans, minivans, and sport-utility...

33 CFR 162.132 - Connecting waters from Lake Huron to Lake Erie; communications rules.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (2) Channel 12 (156.60 mhz) between Lake St. Clair Light and Detroit River Light. (b) Radiotelephone... Cut Light “7” Lake Huron Cut Lighted Buoy “1” Report. Report St. Clair/Black River Junction Light Report. Stag Island Upper Light Report. Report Marine City Salt Dock Light Report. Report Grande Pointe...

33 CFR 118.80 - Lights on bascule bridges.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Lights on bascule bridges. 118.80... LIGHTING AND OTHER SIGNALS § 118.80 Lights on bascule bridges. (a) Lift span lights. Each lift span of... green light which shows only when the span is fully open for the passage of a vessel and by a red light...

33 CFR 118.80 - Lights on bascule bridges.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Lights on bascule bridges. 118.80... LIGHTING AND OTHER SIGNALS § 118.80 Lights on bascule bridges. (a) Lift span lights. Each lift span of... green light which shows only when the span is fully open for the passage of a vessel and by a red light...

33 CFR 118.80 - Lights on bascule bridges.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Lights on bascule bridges. 118.80... LIGHTING AND OTHER SIGNALS § 118.80 Lights on bascule bridges. (a) Lift span lights. Each lift span of... green light which shows only when the span is fully open for the passage of a vessel and by a red light...

Exposing broiler eggs to green, red and white light during incubation.

PubMed

Archer, G S

2017-07-01

Previous work has shown that exposing broiler eggs to white light during incubation can improve hatchability and post-hatch animal welfare. It was hypothesized that due to how different wavelengths of light can affect avian physiology differently, and how pigmented eggshells filter light that different monochromatic wavelengths would have differential effects on hatchability and post-hatch animal welfare indicators. To determine, we incubated chicken eggs (n=6912) under either no light (dark), green light, red light or white light; the light level was 250 lux. White and red light were observed to increase hatch of fertile (P0.05). Fear response of during isolation and tonic immobility was reduced (P0.05) from dark incubated broilers. All light incubated broilers had lower (P<0.05) plasma corticosterone and higher (P<0.05) plasma serotonin concentrations than dark incubated broilers. These results indicate that white light and red light that is a component of it are possibly the key spectrum to improving hatchability and lower fear and stress susceptibility, whereas green light is not as effective. Incubating broiler eggs under these spectrums could be used to improve hatchery efficiency and post-hatch animal welfare at the same time.

Effects of coloured lighting on the perception of interior spaces.

PubMed

Odabaşioğlu, Seden; Olguntürk, Nіlgün

2015-02-01

Use of coloured lighting in interior spaces has become prevalent in recent years. Considerable importance is ascribed to coloured lighting in interior and lighting design. The effects of colour on the perception of interior spaces have been studied as surface colour; but here, the effects of three different types of chromatic light were investigated. The lighting differed in colour (red, green and white) and perceptions of interior space were assessed. 97 participants (59 women, 38 men; M age = 21.4 yr.) evaluated the experiment room on a questionnaire assessing eight evaluative factors: Pleasantness, Arousal, Aesthetics, Usefulness, Comfort, Spaciousness, Colour, and Lighting quality. Perceptions of the room differed by colour of lighting for some of the evaluative factors, but there was no sex difference in perceptions. Interior spaces may be perceived as equally pleasant under white, green and red lighting. Under white lighting a space is perceived as more useful, spacious, clear, and luminous. Green lighting would make the same effect. Green and white lighting were perceived equally comfortable in an interior space. Chromatic coloured lighting was perceived to be more aesthetic than white lighting. The results support previous findings for some evaluative factors, but differed for others.

Method and apparatus for two-dimensional spectroscopy

DOEpatents

DeCamp, Matthew F.; Tokmakoff, Andrei

2010-10-12

Preferred embodiments of the invention provide for methods and systems of 2D spectroscopy using ultrafast, first light and second light beams and a CCD array detector. A cylindrically-focused second light beam interrogates a target that is optically interactive with a frequency-dispersed excitation (first light) pulse, whereupon the second light beam is frequency-dispersed at right angle orientation to its line of focus, so that the horizontal dimension encodes the spatial location of the second light pulse and the first light frequency, while the vertical dimension encodes the second light frequency. Differential spectra of the first and second light pulses result in a 2D frequency-frequency surface equivalent to double-resonance spectroscopy. Because the first light frequency is spatially encoded in the sample, an entire surface can be acquired in a single interaction of the first and second light pulses.

To enhance light extraction of OLED devices by multi-optic layers including a micro lens array

NASA Astrophysics Data System (ADS)

Chiu, Chuang-Hung; Chien, Chao-Heng; Kuo, Yu-Xaong; Lee, Jen-Chi

2014-10-01

In recent years, OLED has advantages including that larger light area, thinner thickness, excellent light uniformity, and can be as a flexible light source. Many display panel and lighting have been started to use the OLED due to OLED without back light system, thus how to make and employ light extracting layer could be important issue to enhance OLED brightness. The purpose of this study is to enhance the light extraction efficiency and light emitting area of OLED, so the micro lens array and the prism reflection layer were provided to enhance the surface light extracting efficiency of OLD. Finally the prism layer and diffusing layer were used to increase the uniformity of emitting area of OLED, which the efficiency of 31% increasing to compare with the OLED without light extracting film.

Improving School Lighting for Video Display Units.

ERIC Educational Resources Information Center

Parker-Jenkins, Marie; Parker-Jenkins, William

1985-01-01

Provides information to identify and implement the key characteristics which contribute to an efficient and comfortable visual display unit (VDU) lighting installation. Areas addressed include VDU lighting requirements, glare, lighting controls, VDU environment, lighting retrofit, optical filters, and lighting recommendations. A checklist to…

The International Year of Light and Light-based Technologies

NASA Astrophysics Data System (ADS)

Pendrill, Ann-Marie

2015-05-01

I report on the opening ceremony of the International Year of Light and Light-based Technologies 2015 (IYL2015), which took place at the UNESCO headquarters in Paris, France, on 19-20 January 2015. Over the two days, more than 1000 participants from all over the world learned more about the fundamental properties of light and advanced photonics applications, the history of optics and its applications through the centuries, light poverty and light pollution, and light for everyday life, health and research.

Precision Guided Airdrop for Vertical Replenishment of Naval Vessels

DTIC Science & Technology

2009-05-07

SEQUENTIALLY FLASHED LINEUP LIGHTS 20. EDGE LIGHTS 21. VERTREP LINEUP LIGHTS 22. VERTREP DROPLINE LIGHTS 2 3 4 5 6 7 8 9 14 10 11 12 13 15 16 17 18 19 20...FLOODLIGHT 2. 3. HIFR AREA MARKING 4. VERTREP LINEUP LINE 5. LANDING AREA PERIPHERY LINE 6. LANDING LINEUP LINES 7. TOUCHDOWN CIRCLE 8. LANDING SPOT 9. LSE...HIFR HEADING LIGHTS 14. HOMING BEACON 15. DECK STATUS LIGHTS 16. OVERHEAD FLOODLIGHTS 17. EXTENDED LINEUP LIGHTS 18. LANDING LINEUP LIGHTS

Nonimaging Optical Illumination System

DOEpatents

Winston, Roland

1994-08-02

A nonimaging illumination optical device for producing selected intensity output over an angular range. The device includes a light reflecting surface (24, 26) around a light source (22) which is disposed opposite the aperture opening of the light reflecting surface (24, 26). The light source (22) has a characteristic dimension which is small relative to one or more of the distance from the light source (22) to the light reflecting surface (24, 26) or the angle subtended by the light source (22) at the light reflecting surface (24, 26).

[Research of spectrum characteristics for light conversion agricultural films].

PubMed

Zhang, Song-pei; Li, Jian-yu; Chen, Juan; Xiao, Yang; Sun, Yu-e

2004-10-01

The solar spectrum and the function spectrum in chrysanthemum and tomato were determined in this paper. The research for a relation plant growth to solar spectrum showed that the efficiency of plant making use of ultraviolet light of 280-380 nm and yellow-green light of 500-600 nm and near IR spectra over 720 nm are lower, that the blue-purple light of 430-480 nm and red light of 630-690 nm are beneficial to enhancing photosynthesis and promoting plant growth. According to plant photosynthesis and solar spectrum characteristic, the author developed CaS:Cu+, Cl- blue light film, and red light film added with CaS:Eu2+, Mn2+, Cl- to convert green light into red light, and discussed the spectrum characteristic of red-blue double peak in agricultural film and rare earth organic complex which could convert ultraviolet light into red light. Just now, the study on light conversion regents in farm films is going to face new breakthrough and the technology of anti-stocks displacement to study red film which can convert near infrared light are worth to attention.

Development of a circadian light source

NASA Astrophysics Data System (ADS)

Nicol, David B.; Ferguson, Ian T.

2002-11-01

Solid state lighting presents a new paradigm for lighting - controllability. Certain characteristics of the lighting environment can be manipulated, because of the possibility of using multiple LEDs of different emission wavelengths as the illumination source. This will provide a new, versatile, general illumination source due to the ability to vary the spectral power distribution. New effects beyond the visual may be achieved that are not possible with conventional light sources. Illumination has long been the primary function of lighting but as the lighting industry has matured the psychological aspects of lighting have been considered by designers; for example, choosing a particular lighting distribution or color variation in retail applications. The next step in the evolution of light is to consider the physiological effects of lighting that cause biological changes in a person within the environment. This work presents the development of a source that may have important bearing on this area of lighting. A circadian light source has been developed to provide an illumination source that works by modulating its correlated color temperature to mimic the changes in natural daylight through the day. In addition, this source can cause or control physiological effects for a person illuminated by it. The importance of this is seen in the human circadian rhythm's peak response corresponding to blue light at ~460 nm which corresponds to the primary spectral difference in increasing color temperature. The device works by adding blue light to a broadband source or mixing polychromatic light to mimic the variation of color temperature observed for the Planckian Locus on the CIE diagram. This device can have several applications including: a tool for researchers in this area, a general illumination lighting technology, and a light therapy device.

Colour Light And Wellbeing: A Case Study Of M Mall 020 George Town, Penang Island

NASA Astrophysics Data System (ADS)

Aqbar Zakaria, Safial; Yii Rou, Ng; Zhi En, Hoi; Iyian, Tai

2017-12-01

Contrary to popular belief, the brightest light or the most colourful light makes good lighting design. However, what makes a good lighting design in interior space is an impeccable composite of art and science. With the application of good lighting design, it can produce an impressive result from enhancing the aesthetic of architectural elements to conveying the right type of ambiance of the interiors. This research intends to address the crucial issues regarding the ways in which lighting designers can communicate the benefits of good lighting and to create a better awareness to users. The objectives of this paper are to outline and explore the features of good and poor lighting design in M Mall O2O based on the lighting design language and profession. The results of this research are mainly qualitative in nature, supported by the professional lighting designers on the definitions of good lighting, personal observation and visual data which were taken in George Town, Penang Island. The case studies on good and poor lighting portrayed in this mall were used as examples to scrutinize the issues raised herein. To achieve the optimum lighting design, a joint approach of focusing on the artistic flair brought forth by lighting and more scientific effort on the calculation levels of lights is crucial. Different functionality requires a different amount of attention on either approach. In conclusion, a good lighting design must be able to enhance the atmosphere and also enrich the quality of the interior architecture. Apart from that, a good lighting design should have good distribution of brightness levels, contrast and different colour temperatures to enhance characters of the interior spaces without neglecting the health and wellbeing aspects.

Blue light for infectious diseases: Propionibacterium acnes, Helicobacter pylori, and beyond?

PubMed Central

Dai, Tianhong; Gupta, Asheesh; Murray, Clinton K.; Vrahas, Mark S.; Tegos, George P.; Hamblin, Michael R.

2012-01-01

Blue light, particularly in the wavelength range of 405–470 nm, has attracted increasing attention due to its intrinsic antimicrobial effect without the addition of exogenous photosensitizers. In addition, it is commonly accepted that blue light is much less detrimental to mammalian cells than ultraviolet irradiation, which is another light-based antimicrobial approach being investigated. In this review, we discussed the blue light sensing systems in microbial cells, antimicrobial efficacy of blue light, the mechanism of antimicrobial effect of blue light, the effects of blue light on mammalian cells, and the effects of blue light on wound healing. It has been reported that blue light can regulate multi-cellular behavior involving cell-to-cell communication via blue light receptors in bacteria, and inhibit biofilm formation and subsequently potentiate light inactivation. At higher radiant exposures, blue light exhibits a broad-spectrum antimicrobial effect against both Gram-positive and Gram-negative bacteria. Blue light therapy is a clinically accepted approach for Propionibacterium acnes infections. Clinical trials have also been conducted to investigate the use of blue light for Helicobacter pylori stomach infections and have shown promising results. Studies on blue light inactivation of important wound pathogenic bacteria, including Staphylococcus aureus and Pseudomonas aeruginosa have also been reported. The mechanism of blue light inactivation of P. acnes, H. pylori, and some oral bacteria is the photo-excitation of intracellular porphyrins and the subsequent production of cytotoxic reactive oxygen species. Although it may be the case that the mechanism of blue light inactivation of wound pathogens (e.g., S. aureus, P. aeruginosa) is the same as that of P. acnes, this hypothesis has not been rigorously tested. Limited and discordant results have been reported regarding the effects of blue light on mammalian cells and wound healing. Under certain wavelengths and radiant exposures, blue light may cause cell dysfunction by the photo-excitation of blue light sensitive chromophores, including flavins and cytochromes, within mitochondria or/and peroxisomes. Further studies should be performed to optimize the optical parameters (e.g., wavelength, radiant exposure) to ensure effective and safe blue light therapies for infectious disease. In addition, studies are also needed to verify the lack of development of microbial resistance to blue light. PMID:22846406

A parallel bubble column system for the cultivation of phototrophic microorganisms.

PubMed

Havel, Jan; Franco-Lara, Ezequiel; Weuster-Botz, Dirk

2008-07-01

An incubator with up to 16 parallel bubble columns was equipped with artificial light sources assuring a light supply with a homogenous light spectrum directly above the bioreactors. Cylindrical light reflecting tubes were positioned around every single bubble column to avoid light scattering effects and to redirect the light from the top onto the cylindrical outer glass surface of each bubble column. The light reflecting tubes were equipped with light intensity filters to control the total light intensity for every single photo-bioreactor. Parallel cultivations of the unicellular obligate phototrophic cyanobacterium, Synechococcus PCC7942, were studied under different constant light intensities ranging from 20 to 102 microE m(-2)s(-1) at a constant humidified air flow rate supplemented with CO(2).

Polarized light modulates light-dependent magnetic compass orientation in birds

PubMed Central

Muheim, Rachel; Sjöberg, Sissel; Pinzon-Rodriguez, Atticus

2016-01-01

Magnetoreception of the light-dependent magnetic compass in birds is suggested to be mediated by a radical-pair mechanism taking place in the avian retina. Biophysical models on magnetic field effects on radical pairs generally assume that the light activating the magnetoreceptor molecules is nondirectional and unpolarized, and that light absorption is isotropic. However, natural skylight enters the avian retina unidirectionally, through the cornea and the lens, and is often partially polarized. In addition, cryptochromes, the putative magnetoreceptor molecules, absorb light anisotropically, i.e., they preferentially absorb light of a specific direction and polarization, implying that the light-dependent magnetic compass is intrinsically polarization sensitive. To test putative interactions between the avian magnetic compass and polarized light, we developed a spatial orientation assay and trained zebra finches to magnetic and/or overhead polarized light cues in a four-arm “plus” maze. The birds did not use overhead polarized light near the zenith for sky compass orientation. Instead, overhead polarized light modulated light-dependent magnetic compass orientation, i.e., how the birds perceive the magnetic field. Birds were well oriented when tested with the polarized light axis aligned parallel to the magnetic field. When the polarized light axis was aligned perpendicular to the magnetic field, the birds became disoriented. These findings are the first behavioral evidence to our knowledge for a direct interaction between polarized light and the light-dependent magnetic compass in an animal. They reveal a fundamentally new property of the radical pair-based magnetoreceptor with key implications for how birds and other animals perceive the Earth’s magnetic field. PMID:26811473

Polarized light modulates light-dependent magnetic compass orientation in birds.

PubMed

Muheim, Rachel; Sjöberg, Sissel; Pinzon-Rodriguez, Atticus

2016-02-09

Magnetoreception of the light-dependent magnetic compass in birds is suggested to be mediated by a radical-pair mechanism taking place in the avian retina. Biophysical models on magnetic field effects on radical pairs generally assume that the light activating the magnetoreceptor molecules is nondirectional and unpolarized, and that light absorption is isotropic. However, natural skylight enters the avian retina unidirectionally, through the cornea and the lens, and is often partially polarized. In addition, cryptochromes, the putative magnetoreceptor molecules, absorb light anisotropically, i.e., they preferentially absorb light of a specific direction and polarization, implying that the light-dependent magnetic compass is intrinsically polarization sensitive. To test putative interactions between the avian magnetic compass and polarized light, we developed a spatial orientation assay and trained zebra finches to magnetic and/or overhead polarized light cues in a four-arm "plus" maze. The birds did not use overhead polarized light near the zenith for sky compass orientation. Instead, overhead polarized light modulated light-dependent magnetic compass orientation, i.e., how the birds perceive the magnetic field. Birds were well oriented when tested with the polarized light axis aligned parallel to the magnetic field. When the polarized light axis was aligned perpendicular to the magnetic field, the birds became disoriented. These findings are the first behavioral evidence to our knowledge for a direct interaction between polarized light and the light-dependent magnetic compass in an animal. They reveal a fundamentally new property of the radical pair-based magnetoreceptor with key implications for how birds and other animals perceive the Earth's magnetic field.

Do Wild Great Tits Avoid Exposure to Light at Night?

PubMed Central

de Jong, Maaike; Ouyang, Jenny Q.; van Grunsven, Roy H. A.; Visser, Marcel E.; Spoelstra, Kamiel

2016-01-01

Studies of wild populations have provided important insights into the effects of artificial light at night on organisms, populations and ecosystems. However, in most studies the exact amount of light at night individuals are exposed to remains unknown. Individuals can potentially control their nighttime light exposure by seeking dark spots within illuminated areas. This uncertainty makes it difficult to attribute effects to a direct effect of light at night, or to indirect effects, e.g., via an effect of light at night on food availability. In this study, we aim to quantify the nocturnal light exposure of wild birds in a previously dark forest-edge habitat, experimentally illuminated with three different colors of street lighting, in comparison to a dark control. During two consecutive breeding seasons, we deployed male great tits (Parus major) with a light logger measuring light intensity every five minutes over a 24h period. We found that three males from pairs breeding in brightly illuminated nest boxes close to green and red lamp posts, were not exposed to more artificial light at night than males from pairs breeding further away. This suggests, based on our limited sample size, that these males could have been avoiding light at night by choosing a roosting place with a reduced light intensity. Therefore, effects of light at night previously reported for this species in our experimental set-up might be indirect. In contrast to urban areas where light is omnipresent, bird species in non-urban areas may evade exposure to nocturnal artificial light, thereby avoiding direct consequences of light at night. PMID:27355354

Light Modulates Ocular Complications in an Albino Rat Model of Type 1 Diabetes Mellitus.

PubMed

Andrawus, Elias; Veildbaum, Gizi; Zemel, Esther; Leibu, Rina; Perlman, Ido; Shehadeh, Naim

2017-07-01

The purpose of the study was to assess potential interactions of light exposure and hyperglycemia upon ocular complications in diabetic rats. Streptozotocin-induced (STZ-induced) diabetic rats ( N = 39) and non-diabetic rats ( N = 9) were distributed into eight groups according to the irradiance and color of the light phase during the 12/12-hour light/dark regime. Follow-up lasted 90 days and included assessment of cataract development and electroretinogram (ERG) recordings. Stress to the retina was also assessed by glial fibrillary acidic protein immunocytochemistry. Cataract development was fast in diabetic rats that were exposed to unattenuated white light or to bright colored lights during the light phase. Diabetic rats that were kept under attenuated brown or yellow light during the light phase exhibited slower rate of cataract development. Electroretinogram responses indicated very severe retinal damage in diabetic rats kept under bright colored lights in the blue-yellow range or bright white light during the light phase. Electroretinogram damage was milder in rats kept under bright red light or attenuated yellow or brown light during the light phase. Glial fibrillary acidic protein expression in retinal Müller cells was consistent with ERG assessment of retinal damage. Attenuating white light and filtering out short wavelengths have a protective effect on the eyes of diabetic rats as evident by slower rate of cataract formation and a smaller degree of retinal damage. Our findings suggest that special glasses attenuating light exposure and filtering out short wavelengths (400-530 nm) may be beneficial for diabetic patients.

Light-Emitting Diodes and Cool White Fluorescent Light Similarly Suppress Pineal Gland Melatonin and Maintain Retinal Function and Morphology in the Rat. Part 1

NASA Technical Reports Server (NTRS)

Holley, Daniel C.; Heeke, D.; Mele, G.

1999-01-01

Currently, the light sources most commonly used in animal habitat lighting are cool white fluorescent or incandescent lamps. We evaluated a novel light-emitting diode (LED) light source for use in animal habitat lighting by comparing its effectiveness to cool white fluorescent light (CWF) in suppressing pineal gland melatonin and maintaining normal retinal physiology and morphology in the rat. Results of pineal melatonin suppression experiments showed equal suppression of pineal melatonin concentrations for LED light and CWF light at five different light illuminances (100, 40, 10, 1 and 0.1 lux). There were no significant differences in melatonin suppression between LED and CWF light when compared to unexposed controls. Retinal physiology was evaluated using electroretinography. Results show no differences in a-wave implicit times and amplitudes or b-wave implicit times and amplitudes between 100-lux LED-exposed rats and 100-lux CWF-exposed rats. Results of retinal histology assessment show no differences in retinal thickness rod outer segment length and number of rod nuclei between rats exposed to 100-lux LED and 100-lux CWF for days. Furthermore, the retinal pigmented epithelium and rod outer segments of all eyes observed were in good condition and of normal thickness. This study indicates that LED light does not cause retinal damage and can suppress pineal melatonin at similar intensities as a conventional CWF light source. These data suggest that LED light sources may be suitable replacements for conventional light sources used in the lighting of rodent vivariums while providing many mechanical and economical advantages.

33 CFR 67.05-20 - Minimum lighting requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... for Lights § 67.05-20 Minimum lighting requirements. The obstruction lighting requirements prescribed... application for authorization to establish more lights, or lights of greater intensity than required to be visible at the distances prescribed: Provided, That the prescribed characteristics of color and flash...

33 CFR 67.05-20 - Minimum lighting requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... for Lights § 67.05-20 Minimum lighting requirements. The obstruction lighting requirements prescribed... application for authorization to establish more lights, or lights of greater intensity than required to be visible at the distances prescribed: Provided, That the prescribed characteristics of color and flash...

33 CFR 67.05-20 - Minimum lighting requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... for Lights § 67.05-20 Minimum lighting requirements. The obstruction lighting requirements prescribed... application for authorization to establish more lights, or lights of greater intensity than required to be visible at the distances prescribed: Provided, That the prescribed characteristics of color and flash...

33 CFR 67.05-20 - Minimum lighting requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... for Lights § 67.05-20 Minimum lighting requirements. The obstruction lighting requirements prescribed... application for authorization to establish more lights, or lights of greater intensity than required to be visible at the distances prescribed: Provided, That the prescribed characteristics of color and flash...

33 CFR 67.05-20 - Minimum lighting requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... for Lights § 67.05-20 Minimum lighting requirements. The obstruction lighting requirements prescribed... application for authorization to establish more lights, or lights of greater intensity than required to be visible at the distances prescribed: Provided, That the prescribed characteristics of color and flash...

49 CFR 176.148 - Artificial lighting.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Artificial lighting. 176.148 Section 176.148... Requirements for Class 1 (Explosive) Materials Precautions During Loading and Unloading § 176.148 Artificial lighting. Electric lights, except arc lights, are the only form of artificial lighting permitted when...

49 CFR 176.148 - Artificial lighting.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Artificial lighting. 176.148 Section 176.148... Requirements for Class 1 (Explosive) Materials Precautions During Loading and Unloading § 176.148 Artificial lighting. Electric lights, except arc lights, are the only form of artificial lighting permitted when...

Damage of photoreceptor-derived cells in culture induced by light emitting diode-derived blue light

PubMed Central

Kuse, Yoshiki; Ogawa, Kenjiro; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Hara, Hideaki

2014-01-01

Our eyes are increasingly exposed to light from the emitting diode (LED) light of video display terminals (VDT) which contain much blue light. VDTs are equipped with televisions, personal computers, and smart phones. The present study aims to clarify the mechanism underlying blue LED light-induced photoreceptor cell damage. Murine cone photoreceptor-derived cells (661 W) were exposed to blue, white, or green LED light (0.38 mW/cm2). In the present study, blue LED light increased reactive oxygen species (ROS) production, altered the protein expression level, induced the aggregation of short-wavelength opsins (S-opsin), resulting in severe cell damage. While, blue LED light damaged the primary retinal cells and the damage was photoreceptor specific. N-Acetylcysteine (NAC), an antioxidant, protected against the cellular damage induced by blue LED light. Overall, the LED light induced cell damage was wavelength-, but not energy-dependent and may cause more severe retinal photoreceptor cell damage than the other LED light. PMID:24909301

Subjective quality of video sequences rendered on LCD with local backlight dimming at different lighting conditions

NASA Astrophysics Data System (ADS)

Mantel, Claire; Korhonen, Jari; Pedersen, Jesper M.; Bech, Søren; Andersen, Jakob Dahl; Forchhammer, Søren

2015-01-01

This paper focuses on the influence of ambient light on the perceived quality of videos displayed on Liquid Crystal Display (LCD) with local backlight dimming. A subjective test assessing the quality of videos with two backlight dimming methods and three lighting conditions, i.e. no light, low light level (5 lux) and higher light level (60 lux) was organized to collect subjective data. Results show that participants prefer the method exploiting local dimming possibilities to the conventional full backlight but that this preference varies depending on the ambient light level. The clear preference for one method at the low light conditions decreases at the high ambient light, confirming that the ambient light significantly attenuates the perception of the leakage defect (light leaking through dark pixels). Results are also highly dependent on the content of the sequence, which can modulate the effect of the ambient light from having an important influence on the quality grades to no influence at all.

Compressive light field imaging

NASA Astrophysics Data System (ADS)

Ashok, Amit; Neifeld, Mark A.

2010-04-01

Light field imagers such as the plenoptic and the integral imagers inherently measure projections of the four dimensional (4D) light field scalar function onto a two dimensional sensor and therefore, suffer from a spatial vs. angular resolution trade-off. Programmable light field imagers, proposed recently, overcome this spatioangular resolution trade-off and allow high-resolution capture of the (4D) light field function with multiple measurements at the cost of a longer exposure time. However, these light field imagers do not exploit the spatio-angular correlations inherent in the light fields of natural scenes and thus result in photon-inefficient measurements. Here, we describe two architectures for compressive light field imaging that require relatively few photon-efficient measurements to obtain a high-resolution estimate of the light field while reducing the overall exposure time. Our simulation study shows that, compressive light field imagers using the principal component (PC) measurement basis require four times fewer measurements and three times shorter exposure time compared to a conventional light field imager in order to achieve an equivalent light field reconstruction quality.

Aethalometer

DOEpatents

Hansen, Anthony D.

1990-01-01

An improved aethalometer (10) having a single light source (18) and a single light detector (20) and two light paths (21, 22) from the light source (18) to the light detector (20). A quartz fiber filter (13) is inserted in the device, the filter (13) having a collection area (23) in one light path (21) and a reference area (24) in the other light path (22). A gas flow path (46) through the aethalometer housing (11) allows ambient air to flow through the collection area (23) of the filter (13) so that aerosol particles can be collected on the filter. A rotating disk (31) with an opening (33) therethrough allows light for the light source (18) to pass alternately through the two light paths (21, 22). The voltage output of the detector (20) is applied to a VCO (52) and the VCO pulses for light transmission separately through the two light paths (21, 22 ) are counted and compared to determine the absorption coefficient of the collected aerosol particles.

Lamp method and apparatus using multiple reflections

DOEpatents

MacLennan, Donald A.; Turner, Brian P.

2001-01-01

An electrodeless microwave discharge lamp includes an envelope with a discharge forming fill disposed therein which emits light, the fill being capable of absorbing light at one wavelength and re-emitting the absorbed light at a different wavelength, the light emitted from the fill having a first spectral power distribution in the absence of reflection of light back into the fill, a source of microwave energy coupled to the fill to excite the fill and cause the fill to emit light, and a reflector disposed within the microwave cavity and configured to reflect at least some of the light emitted by the fill back into the fill while allowing some light to exit, the exiting light having a second spectral power distribution with proportionately more light in the visible region as compared to the first spectral power distribution, wherein the light re-emitted by the fill is shifted in wavelength with respect to the absorbed light and the magnitude of the shift is in relation to an effective optical path length.

Energy and economic efficiency alternatives for electric lighting in commercial buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robbins, C L; Hunter, K C; Carlisle, N

1985-10-01

This report investigates current efficient alternatives for replacing or supplementing electric lighting systems in commercial buildings. Criteria for establishing the economic attractiveness of various lighting alternatives are defined and the effect of future changes in building lighting on utility capacity. The report focuses on the energy savings potential, economic efficiency, and energy demand reduction of three categories of lighting alternatives: (1) use of a renewable resource (daylighting) to replace or supplement electric lighting; (2) use of task/ambient lighting in lieu of overhead task lighting; and (3) equipment changes to improve lighting energy efficiency. The results indicate that all three categoriesmore » offer opportunities to reduce lighting energy use in commercial buildings. Further, reducing lighting energy causes a reduction in cooling energy use and cooling capacity while increasing heating energy use. It does not typically increase heating capacity because the use of lighting in the building does not offset the need for peak heating at night.« less

33 CFR 162.132 - Connecting waters from Lake Huron to Lake Erie; communications rules.

Code of Federal Regulations, 2011 CFR

2011-07-01

... monitor: (1) Channel 11 (156.55 mhz) between Lake Huron Cut Lighted Buoy 11 and Lake St. Clair Light; and (2) Channel 12 (156.60 mhz) between Lake St. Clair Light and Detroit River Light. (b) Radiotelephone... Cut Light “7” Lake Huron Cut Lighted Buoy “1” Report. Report St. Clair/Black River Junction Light...

Reducing the ecological consequences of night-time light pollution: options and developments

PubMed Central

Gaston, Kevin J; Davies, Thomas W; Bennie, Jonathan; Hopkins, John

2012-01-01

1. Much concern has been expressed about the ecological consequences of night-time light pollution. This concern is most often focused on the encroachment of artificial light into previously unlit areas of the night-time environment, but changes in the spectral composition, duration and spatial pattern of light are also recognized as having ecological effects. 2. Here, we examine the potential consequences for organisms of five management options to reduce night-time light pollution. These are to (i) prevent areas from being artificially lit; (ii) limit the duration of lighting; (iii) reduce the ‘trespass’ of lighting into areas that are not intended to be lit (including the night sky); (iv) change the intensity of lighting; and (v) change the spectral composition of lighting. 3. Maintaining and increasing natural unlit areas is likely to be the most effective option for reducing the ecological effects of lighting. However, this will often conflict with other social and economic objectives. Decreasing the duration of lighting will reduce energy costs and carbon emissions, but is unlikely to alleviate many impacts on nocturnal and crepuscular animals, as peak times of demand for lighting frequently coincide with those in the activities of these species. Reducing the trespass of lighting will maintain heterogeneity even in otherwise well-lit areas, providing dark refuges that mobile animals can exploit. Decreasing the intensity of lighting will reduce energy consumption and limit both skyglow and the area impacted by high-intensity direct light. Shifts towards ‘whiter’ light are likely to increase the potential range of environmental impacts as light is emitted across a broader range of wavelengths. 4. Synthesis and applications. The artificial lightscape will change considerably over coming decades with the drive for more cost-effective low-carbon street lighting solutions and growth in the artificially lit area. Developing lighting strategies that minimize adverse ecological impacts while balancing the often conflicting requirements of light for human utility, comfort and safety, aesthetic concerns, energy consumption and carbon emission reduction constitute significant future challenges. However, as both lighting technology and understanding of its ecological effects develop, there is potential to identify adaptive solutions that resolve these conflicts. PMID:23335816

Reducing the ecological consequences of night-time light pollution: options and developments.

PubMed

Gaston, Kevin J; Davies, Thomas W; Bennie, Jonathan; Hopkins, John

2012-12-01

1. Much concern has been expressed about the ecological consequences of night-time light pollution. This concern is most often focused on the encroachment of artificial light into previously unlit areas of the night-time environment, but changes in the spectral composition, duration and spatial pattern of light are also recognized as having ecological effects.2. Here, we examine the potential consequences for organisms of five management options to reduce night-time light pollution. These are to (i) prevent areas from being artificially lit; (ii) limit the duration of lighting; (iii) reduce the 'trespass' of lighting into areas that are not intended to be lit (including the night sky); (iv) change the intensity of lighting; and (v) change the spectral composition of lighting.3. Maintaining and increasing natural unlit areas is likely to be the most effective option for reducing the ecological effects of lighting. However, this will often conflict with other social and economic objectives. Decreasing the duration of lighting will reduce energy costs and carbon emissions, but is unlikely to alleviate many impacts on nocturnal and crepuscular animals, as peak times of demand for lighting frequently coincide with those in the activities of these species. Reducing the trespass of lighting will maintain heterogeneity even in otherwise well-lit areas, providing dark refuges that mobile animals can exploit. Decreasing the intensity of lighting will reduce energy consumption and limit both skyglow and the area impacted by high-intensity direct light. Shifts towards 'whiter' light are likely to increase the potential range of environmental impacts as light is emitted across a broader range of wavelengths.4.Synthesis and applications. The artificial lightscape will change considerably over coming decades with the drive for more cost-effective low-carbon street lighting solutions and growth in the artificially lit area. Developing lighting strategies that minimize adverse ecological impacts while balancing the often conflicting requirements of light for human utility, comfort and safety, aesthetic concerns, energy consumption and carbon emission reduction constitute significant future challenges. However, as both lighting technology and understanding of its ecological effects develop, there is potential to identify adaptive solutions that resolve these conflicts.

Human phase response curve to a 1 h pulse of bright white light

PubMed Central

St Hilaire, Melissa A; Gooley, Joshua J; Khalsa, Sat Bir S; Kronauer, Richard E; Czeisler, Charles A; Lockley, Steven W

2012-01-01

The phase resetting response of the human circadian pacemaker to light depends on the timing of exposure and is described by a phase response curve (PRC). The current study aimed to construct a PRC for a 1 h exposure to bright white light (∼8000 lux) and to compare this PRC to a <3 lux dim background light PRC. These data were also compared to a previously completed 6.7 h bright white light PRC and a <15 lux dim background light PRC constructed under similar conditions. Participants were randomized for exposure to 1 h of either bright white light (n= 18) or <3 lux dim background light (n= 18) scheduled at 1 of 18 circadian phases. Participants completed constant routine (CR) procedures in dim light (<3 lux) before and after the light exposure to assess circadian phase. Phase shifts were calculated as the difference in timing of dim light melatonin onset (DLMO) during pre- and post-stimulus CRs. Exposure to 1 h of bright white light induced a Type 1 PRC with a fitted peak-to-trough amplitude of 2.20 h. No discernible PRC was observed in the <3 lux dim background light PRC. The fitted peak-to-trough amplitude of the 1 h bright light PRC was ∼40% of that for the 6.7 h PRC despite representing only 15% of the light exposure duration, consistent with previous studies showing a non-linear duration–response function for the effects of light on circadian resetting. PMID:22547633

Human phase response curve to a 1 h pulse of bright white light.

PubMed

St Hilaire, Melissa A; Gooley, Joshua J; Khalsa, Sat Bir S; Kronauer, Richard E; Czeisler, Charles A; Lockley, Steven W

2012-07-01

The phase resetting response of the human circadian pacemaker to light depends on the timing of exposure and is described by a phase response curve (PRC). The current study aimed to construct a PRC for a 1 h exposure to bright white light (∼8000 lux) and to compare this PRC to a <3 lux dim background light PRC. These data were also compared to a previously completed 6.7 h bright white light PRC and a <15 lux dim background light PRC constructed under similar conditions. Participants were randomized for exposure to 1 h of either bright white light (n=18) or <3 lux dim background light (n=18) scheduled at 1 of 18 circadian phases. Participants completed constant routine (CR) procedures in dim light (<3 lux) before and after the light exposure to assess circadian phase. Phase shifts were calculated as the difference in timing of dim light melatonin onset (DLMO) during pre- and post-stimulus CRs. Exposure to 1 h of bright white light induced a Type 1 PRC with a fitted peak-to-trough amplitude of 2.20 h. No discernible PRC was observed in the <3 lux dim background light PRC. The fitted peak-to-trough amplitude of the 1 h bright light PRC was ∼40% of that for the 6.7 h PRC despite representing only 15% of the light exposure duration, consistent with previous studies showing a non-linear duration–response function for the effects of light on circadian resetting.

[LIGHT POLLUTION AS THE HYGIENIC PROBLEM].

PubMed

Kaptsov, V A; Gerasev, V F; Deynego, V N

2015-01-01

Mass introduction of lighting devices according to the concept of "maximum coverage area" and multistoried buildings of cities gave rise to light pollution, which became a problem for astronomers, ecologists and hygienists. Analysis of modern lighting devices and installations has shown that about 30-45% of the luminous flux becomes the light pollution. Night lighting of cities causes both direct and indirect damage to the environment, leads to unnecessary energy wastes. So in the USA due to excessive light there is wasted about 2 million barrels of oil per day. Light pollution affects the human hormonal system, causing various health disorders, such as insomnia and depression as a consequence. The light pollution through the ganglion cells of the retina affects the synthesis of melatonin by the pineal gland (epiphysis) and contributes to its calcification, which greatly affects the human psyche. At present, many countries have been paying much state attention to this problem via delivery of national documents and change of the concept of the designing of lighting devices and installations. The essence of this concept--to shine with a preset quality of light only in the right place at the specified time interval. This reduces the light pollution, saves energy and increases the environmental safety of lighting. There is presented an example of a technical solution to reduce the light pollution in the application of the light panel in the form of the gradient of the light guide generator project development.

VALIDITATION OF A LIGHT QUESTIONNAIRE WITH REAL-LIFE PHOTOPIC ILLUMINANCE MEASUREMENTS: THE HARVARD LIGHT EXPOSURE ASSESSMENT QUESTIONNAIRE

PubMed Central

Bajaj, Archna; Rosner, Bernard; Lockley, Steven; Schernhammer, Eva S.

2011-01-01

Background Light exposure at night is now considered a probable carcinogen. To study the effects of light on chronic diseases like cancer, methods to measure light exposure in large observational studies are needed. We aimed to investigate the validity of self-reported current light exposure. Methods We developed a self-administered semiquantitative light questionnaire, the Harvard Light Exposure Assessment (H-LEA) questionnaire, and compared photopic scores derived from this questionnaire with actual photopic and circadian measures obtained from a real-life 7-day light meter application among 132 women (85 rotating night shift workers and 47 day workers) participating in the Nurses' Health Study II. Results After adjustment for age, BMI, collection day, and night work status, the overall partial Spearman correlation between self-report of light exposure and actual photopic light measurements was 0.72 (P<0.001; Kendall τ =0.57) and 0.73 (P<0.0001; Kendall τ =0.58) when correlating circadian light measurements. There were only minimal differences in accuracy of self-report of light exposure and photopic or circadian light measurement between day (r=0.77 and 0.78, respectively) and rotating night shift workers (r=0.68 and 0.69, respectively). Conclusions The results of this study provide evidence of the criterion validity of self-reported light exposure using the H-LEA questionnaire. Impact: This questionnaire is a practical method of assessing light exposure in large scale epidemiologic studies. PMID:21737411

Acute Effects of Morning Light on Plasma Glucose and Triglycerides in Healthy Men and Men with Type 2 Diabetes.

PubMed

Versteeg, Ruth I; Stenvers, Dirk J; Visintainer, Dana; Linnenbank, Andre; Tanck, Michael W; Zwanenburg, Gooitzen; Smilde, Age K; Fliers, Eric; Kalsbeek, Andries; Serlie, Mireille J; la Fleur, Susanne E; Bisschop, Peter H

2017-04-01

Ambient light intensity is signaled directly to hypothalamic areas that regulate energy metabolism. Observational studies have shown associations between ambient light intensity and plasma glucose and lipid levels, but human data on the acute metabolic effects of light are scarce. Since light is the main signal indicating the onset of the diurnal phase of physical activity and food intake in humans, we hypothesized that bright light would affect glucose and lipid metabolism. Therefore, we determined the acute effects of bright light on plasma glucose and lipid concentrations in 2 randomized crossover trials: (1) in 8 healthy lean men and (2) in 8 obese men with type 2 diabetes. From 0730 h, subjects were exposed to either bright light (4000 lux) or dim light (10 lux) for 5 h. After 1 h of light exposure, subjects consumed a 600-kcal mixed meal. Primary endpoints were fasting and postprandial plasma glucose levels. In healthy men, bright light did not affect fasting or postprandial plasma glucose levels. However, bright light increased fasting and postprandial plasma triglycerides. In men with type 2 diabetes, bright light increased fasting and postprandial glucose levels. In men with type 2 diabetes, bright light did not affect fasting triglyceride levels but increased postprandial triglyceride levels. We show that ambient light intensity acutely affects human plasma glucose and triglyceride levels. Our findings warrant further research into the consequences of the metabolic effects of light for the diagnosis and prevention of hyperglycemia and dyslipidemia.

Carambola optics for recycling of light.

PubMed

Leutz, Ralf; Fu, Ling; Ries, Harald

2006-04-20

Recycling of light allows the luminance (radiance) emitted by a light source to be increased at the cost of reducing the total luminous flux (radiant power). Recycling of light means returning part of the emitted light to the source, where part of it will escape absorption. An optical design that is suitable for multiple and controlled recycling is described. Carambola optics is named for its resemblance to star fruit. Several pairs of mirrors or prisms redirect light repeatedly onto the source, thus achieving multiple transits of the light through the source. This recycled light exits the carambola in the same phase space as light directly emitted and not recycled.

High temperature, minimally invasive optical sensing modules

DOEpatents

Riza, Nabeel Agha [Oviedo, FL; Perez, Frank [Tujunga, CA

2008-02-05

A remote temperature sensing system includes a light source selectively producing light at two different wavelengths and a sensor device having an optical path length that varies as a function of temperature. The sensor receives light emitted by the light source and redirects the light along the optical path length. The system also includes a detector receiving redirected light from the sensor device and generating respective signals indicative of respective intensities of received redirected light corresponding to respective wavelengths of light emitted by the light source. The system also includes a processor processing the signals generated by the detector to calculate a temperature of the device.

Stray-light suppression in a reflecting white-light coronagraph

NASA Technical Reports Server (NTRS)

Romoli, Marco; Weiser, Heinz; Gardner, Larry D.; Kohl, John L.

1993-01-01

An analysis of stray-light suppression in the white-light channel of the Ultraviolet Coronagraph Spectrometer experiment for the Solar and Heliospheric Observatory is reported. The white-light channel consists of a reflecting telescope with external and internal occultation and a polarimeter section. Laboratory tests and analytical methods are used to perform the analysis. The various stray-light contributions are classified in two main categories: the contribution from sunlight that passes directly through the entrance aperture and the contribution of sunlight that is diffracted by the edges of the entrance aperture. Values of the stray-light contributions from various sources and the total stray-light level for observations at heliocentric heights from 1.4 to 5 solar radii are derived. Anticipated signal-to-stray-light ratios are presented together with the effective stray-light rejection by the polarimeter, demonstrating the efficacy of the stray-light suppression design.

Disruption of Circadian Rhythms by Light During Day and Night.

PubMed

Figueiro, Mariana G

2017-06-01

This study aims to discuss possible reasons why research to date has not forged direct links between light at night, acute melatonin suppression or circadian disruption, and risks for disease. Data suggest that irregular light-dark patterns or light exposures at the wrong circadian time can lead to circadian disruption and disease risks. However, there remains an urgent need to: (1) specify light stimulus in terms of circadian rather than visual response; (2) when translating research from animals to humans, consider species-specific spectral and absolute sensitivities to light; (3) relate the characteristics of photometric measurement of light at night to the operational characteristics of the circadian system; and (4) examine how humans may be experiencing too little daytime light, not just too much light at night. To understand the health effects of light-induced circadian disruption, we need to measure and control light stimulus during the day and at night.

Hybrid daylight/light-emitting diode illumination system for indoor lighting.

PubMed

Ge, Aiming; Qiu, Peng; Cai, Jinlin; Wang, Wei; Wang, Junwei

2014-03-20

A hybrid illumination method using both daylight and light-emitting diodes (LEDs) for indoor lighting is presented in this study. The daylight can be introduced into the indoor space by a panel-integration system. The daylight part and LEDs are combined within a specific luminaire that can provide uniform illumination. The LEDs can be turned on and dimmed through closed-loop control when the daylight illuminance is inadequate. We simulated the illumination and calculated the indoor lighting efficiency of our hybrid daylight and LED lighting system, and compared this with that of LED and fluorescent lighting systems. Simulation results show that the efficiency of the hybrid daylight/LED illumination method is better than that of LED and traditional lighting systems, under the same lighting conditions and lighting time; the method has hybrid lighting average energy savings of T5 66.28%, and that of the LEDs is 41.62%.

Dynamic resetting of the human circadian pacemaker by intermittent bright light

NASA Technical Reports Server (NTRS)

Rimmer, D. W.; Boivin, D. B.; Shanahan, T. L.; Kronauer, R. E.; Duffy, J. F.; Czeisler, C. A.

2000-01-01

In humans, experimental studies of circadian resetting typically have been limited to lengthy episodes of exposure to continuous bright light. To evaluate the time course of the human endogenous circadian pacemaker's resetting response to brief episodes of intermittent bright light, we studied 16 subjects assigned to one of two intermittent lighting conditions in which the subjects were presented with intermittent episodes of bright-light exposure at 25- or 90-min intervals. The effective duration of bright-light exposure was 31% or 63% compared with a continuous 5-h bright-light stimulus. Exposure to intermittent bright light elicited almost as great a resetting response compared with 5 h of continuous bright light. We conclude that exposure to intermittent bright light produces robust phase shifts of the endogenous circadian pacemaker. Furthermore, these results demonstrate that humans, like other species, exhibit an enhanced sensitivity to the initial minutes of bright-light exposure.

Effects of light quality on pod elongation in soybean (Glycine max (L.) Merr.) and cowpea (Vigna unguiculata (L.) Walp.).

PubMed

Tanaka, Seiya; Ario, Nobuyuki; Nakagawa, Andressa Camila Seiko; Tomita, Yuki; Murayama, Naoki; Taniguchi, Takatoshi; Hamaoka, Norimitsu; Iwaya-Inoue, Mari; Ishibashi, Yushi

2017-06-03

Soybean pods are located at the nodes, where they are in the shadow, whereas cowpea pods are located outside of the leaves and are exposed to sunlight. To compare the effects of light quality on pod growth in soybean and cowpea, we measured the length of pods treated with white, blue, red or far-red light. In both species, pods elongated faster during the dark period than during the light period in all light treatments except red light treatment in cowpea. Red light significantly suppressed pod elongation in soybean during the dark and light periods. On the other hand, the elongation of cowpea pods treated with red light markedly promoted during the light period. These results suggested that the difference in the pod set sites between soybean and cowpea might account for the difference in their red light responses for pod growth.

Computational Modeling to Limit the Impact Displays and Indicator Lights Have on Habitable Volume Operational Lighting Constraints

NASA Technical Reports Server (NTRS)

Clark, T. A.; Salazar, G. A.; Brainard, G. C.; Litaker, H. L.; Hanifin, J.; Schwing, B. M.

2016-01-01

Even with no ambient lighting system "on", the International Space Station glows at night. The glow is caused by indicator lamps and displays that are not included with the specification of the ambient lighting system. How does this impact efforts to improve the astronaut's lighting environment to promote more effective sleep patterns? Do the extra indicators and displays add enough light to change the spectrum of light the crew sees during the day as well? If spacecraft environments are specifically engineered to have an ambient lighting system that emits a spectrum promoting a healthy circadian response, is there a way control the impact? The goal of this project is to investigate how additional light sources, such as displays and indicators change the effective light spectrum of the architectural lighting system and how impacts can be mitigated.

14 CFR 27.1401 - Anticollision light system.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Anticollision light system. 27.1401 Section... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1401 Anticollision light system. (a... light system that— (1) Consists of one or more approved anticollision lights located so that their...

14 CFR 29.1401 - Anticollision light system.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Anticollision light system. 29.1401 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1401 Anticollision light system. (a... light system that— (1) Consists of one or more approved anticollision lights located so that their...

14 CFR 27.1401 - Anticollision light system.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Anticollision light system. 27.1401 Section... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1401 Anticollision light system. (a... light system that— (1) Consists of one or more approved anticollision lights located so that their...

49 CFR 229.127 - Cab lights.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Cab lights. 229.127 Section 229.127 Transportation... lights. (a) Each locomotive shall have cab lights which will provide sufficient illumination for the... normal positions in the cab. These lights shall be located, constructed, and maintained so that light...

46 CFR 112.43-9 - Signaling lights.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Signaling lights. 112.43-9 Section 112.43-9 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Lighting Systems § 112.43-9 Signaling lights. Each signaling light must be...

49 CFR 229.127 - Cab lights.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Cab lights. 229.127 Section 229.127 Transportation... lights. (a) Each locomotive shall have cab lights which will provide sufficient illumination for the... normal positions in the cab. These lights shall be located, constructed, and maintained so that light...

46 CFR 112.43-9 - Signaling lights.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Signaling lights. 112.43-9 Section 112.43-9 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Lighting Systems § 112.43-9 Signaling lights. Each signaling light must be...

46 CFR 112.43-9 - Signaling lights.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Signaling lights. 112.43-9 Section 112.43-9 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Lighting Systems § 112.43-9 Signaling lights. Each signaling light must be...

49 CFR 229.127 - Cab lights.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Cab lights. 229.127 Section 229.127 Transportation... lights. (a) Each locomotive shall have cab lights which will provide sufficient illumination for the... normal positions in the cab. These lights shall be located, constructed, and maintained so that light...

49 CFR 229.127 - Cab lights.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Cab lights. 229.127 Section 229.127 Transportation... lights. (a) Each locomotive shall have cab lights which will provide sufficient illumination for the... normal positions in the cab. These lights shall be located, constructed, and maintained so that light...

14 CFR 27.1401 - Anticollision light system.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Anticollision light system. 27.1401 Section... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1401 Anticollision light system. (a... light system that— (1) Consists of one or more approved anticollision lights located so that their...

46 CFR 112.43-9 - Signaling lights.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Signaling lights. 112.43-9 Section 112.43-9 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Lighting Systems § 112.43-9 Signaling lights. Each signaling light must be...

14 CFR 27.1401 - Anticollision light system.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Anticollision light system. 27.1401 Section... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1401 Anticollision light system. (a... light system that— (1) Consists of one or more approved anticollision lights located so that their...

14 CFR 29.1401 - Anticollision light system.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Anticollision light system. 29.1401 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1401 Anticollision light system. (a... light system that— (1) Consists of one or more approved anticollision lights located so that their...

14 CFR 27.1401 - Anticollision light system.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Anticollision light system. 27.1401 Section... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1401 Anticollision light system. (a... light system that— (1) Consists of one or more approved anticollision lights located so that their...

14 CFR 29.1401 - Anticollision light system.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Anticollision light system. 29.1401 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1401 Anticollision light system. (a... light system that— (1) Consists of one or more approved anticollision lights located so that their...

49 CFR 229.127 - Cab lights.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Cab lights. 229.127 Section 229.127 Transportation... lights. (a) Each locomotive shall have cab lights which will provide sufficient illumination for the... normal positions in the cab. These lights shall be located, constructed, and maintained so that light...

46 CFR 112.43-9 - Signaling lights.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Signaling lights. 112.43-9 Section 112.43-9 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Lighting Systems § 112.43-9 Signaling lights. Each signaling light must be...

Evaluation of Metal Halide, Plasma, and LED Lighting Technologies for a Hydrogen Fuel Cell Mobile Light (H 2 LT)

DOE PAGES

Miller, L. B.; Donohoe, S. P.; Jones, M. H.; ...

2015-04-22

This article reports on the testing and comparison of a prototype hydrogen fuel cell light tower (H2LT) and a conventional diesel-powered metal halide light trailer for use in road maintenance and construction activities. The prototype was originally outfitted with plasma lights and then with light-emitting diode (LED) luminaires. Light output and distribution, lighting energy efficiency (i.e., efficacy), power source thermal efficiency, and fuel costs are compared. The metal halide luminaires have 2.2 and 3.1 times more light output than the plasma and LED luminaires, respectively, but they require more power/lumen to provide that output. The LED luminaires have 1.6 timesmore » better light efficacy than either the metal halide or plasma luminaires. The light uniformity ratios produced by the plasma and LED towers are acceptable. The fuel cell thermal efficiency at the power required to operate the plasma lights is 48%, significantly higher than the diesel generator efficiency of 23% when operating the metal halide lights. Due to the increased efficiency of the fuel cell and the LED lighting, the fuel cost per lumen-hour of the H2LT is 62% of the metal halide diesel light tower assuming a kilogram of hydrogen is twice the cost of a gallon of diesel fuel.« less

Newly patented process enables low-cost solution for increasing white light spectrum of LEDs

NASA Astrophysics Data System (ADS)

Spanard, Jan-Marie

2017-10-01

A newly patented process for completing the spectral light array emitted by LED bulbs provides a low-cost method for producing better human centered lighting (HCL). This process uses non-luminescent colorant filters, filling out the jagged LED spectral emission into a full, white light array. While LED bulbs have the distinct economic advantages of using less energy, producing less heat and lasting years longer than traditional incandescent bulbs, the persistent metameric failure of LED bulbs has resulted in slower, and sometimes reluctant, adoption of LED lighting by the residential, retail and architectural markets. Adding missing wavelengths to LED generated bulbs via colorant filters increases the aesthetic appeal of the light by decreasing current levels of metameric failure, reducing the `flatness', `harshness', and `dullness' of LED generated light reported by consumers. LED phosphor-converted light can be successfully tuned to "whiter" white light with selective color filtering using permanent, durable transparent pigments. These transparent pigments are selectively applied in combination with existing manufacturing technologies and utilized as a final color-tuning step in bulb design. The quantity of emitted light chosen for color filtering can be adjusted from 1% to 100% of emitted light, creating a custom balance of light quantity with light quality. This invention recognizes that "better light" is frequently chosen over "more light" in the consumer marketplace.

Development of an antimicrobial blended white LED system containing pulsed 405nm LEDs for decontamination applications

NASA Astrophysics Data System (ADS)

Gillespie, Jonathan B.; Maclean, Michelle; Wilson, Mark P.; Given, Martin J.; MacGregor, Scott J.

2017-03-01

This study details the design, build and testing of a prototype antimicrobial blended white light unit containing pulsed red, yellow, green and 405nm LEDs. With a push for alternative methods of disinfection, optical methods have become a topic of interest. Ultra-violet (UV) light is widely known for its antimicrobial properties however; 405nm light has demonstrated significant antimicrobial properties against many common hospital acquired pathogens. In this study, a pulsed, blended, white-light prototype with a high content of 405 nm antimicrobial light, was designed, built and tested. Antimicrobial efficacy testing of the prototype was conducted using Staphylococcus aureus and Pseudomonas. aeruginosa, two bacteria which are common causes of hospital acquired infections. These were exposure to 3 different light outputs from the prototype and the surviving bacteria enumerated. Results showed that the mixed light output provided a much better CRI and light output under which to work. Also, the light output containing 405 nm light provided an antimicrobial effect, with decontamination of 103 CFUml-1 populations of both bacterial species. The other light content (red, yellow, green) had no beneficial or adverse effects on the antimicrobial properties of the 405nm light. The results suggest that with further development, it could be possible to produce an antimicrobial blended white light containing pulsed 405nm light that could supplement or even replace standard white lighting in certain environments.

Phase response of the Arabidopsis thaliana circadian clock to light pulses of different wavelengths.

PubMed

Ohara, Takayuki; Fukuda, Hirokazu; Tokuda, Isao T

2015-04-01

Light is known as one of the most powerful environmental time cues for the circadian system. The quality of light is characterized by its intensity and wavelength. We examined how the phase response of Arabidopsis thaliana depends on the wavelength of the stimulus light and the type of light perturbation. Using transgenic A. thaliana expressing a luciferase gene, we monitored the rhythm of the bioluminescence signal. We stimulated the plants under constant red light using 3 light perturbation treatments: (1) increasing the red light intensity, (2) turning on a blue light while turning off the red light, and (3) turning on a blue light while keeping the red light on. To examine the phase response properties, we generated a phase transition curve (PTC), which plots the phase after the perturbation as a function of the phase before the perturbation. To evaluate the effect of the 3 light perturbation treatments, we simulated PTCs using a mathematical model of the plant circadian clock and fitted the simulated PTCs to the experimentally measured PTCs. Among the 3 treatments, perturbation (3) provided the strongest stimulus. The results indicate that the color of the stimulus light and the type of pulse administration affect the phase response in a complex manner. Moreover, the results suggest the involvement of interaction between red and blue light signaling pathways in resetting of the plant circadian clock. © 2015 The Author(s).

Is part-night lighting an effective measure to limit the impacts of artificial lighting on bats?

PubMed

Azam, Clémentine; Kerbiriou, Christian; Vernet, Arthur; Julien, Jean-François; Bas, Yves; Plichard, Laura; Maratrat, Julie; Le Viol, Isabelle

2015-12-01

As light pollution is currently considered to be a major threat to biodiversity, different lighting management options are being explored to mitigate the impact of artificial lighting on wildlife. Although part-night lighting schemes have been adopted by many local authorities across Europe to reduce the carbon footprint and save energy, their effects on biodiversity are unknown. Through a paired, in situ experiment, we compared the activity levels of 8 bat species under unlit, part-night, and full-night lighting treatments in a rural area located 60 km south of Paris, France. We selected 36 study locations composed of 1 lit site and a paired unlit control site; 24 of these sites were located in areas subject to part-night lighting schemes, and 12 sites were in areas under standard, full-night lighting. There was significantly more activity on part-night lighting sites compared to full-night lighting sites for the late-emerging, light-sensitive Plecotus spp., and a similar pattern was observable for Myotis spp., although not significant. In contrast, part-night lighting did not influence the activity of early emerging bat species around streetlights, except for Pipistrellus pipistrellus for which there was significantly less activity on part-night lighting sites than on full-night lighting sites. Overall, no significant difference in activity between part- and full-night lighting sites were observed in 5 of the 8 species studied, suggesting that current part-night lighting schemes fail to encompass the range of activity of most bat species. We recommend that such schemes start earlier at night to effectively mitigate the adverse effects of artificial lighting on light-sensitive species, particularly along ecological corridors that are especially important to the persistence of biodiversity in urban landscapes. © 2015 John Wiley & Sons Ltd.

The effects of feedback lighting on the circadian drinking rhythm in the diurnal new world primate Saimiri sciureus

NASA Technical Reports Server (NTRS)

Ferraro, J. S.; Sulzman, F. M.

1988-01-01

Feedback lighting provides illumination primarily during the subjective night (i.e., the photosensitive portion of the circadian cycle) in response to a given behavior. This technique has previously been used to test the nonparametric model of entrainment in nocturnal rodents. In three species (Rattus norvegicus, Mesocricetus auratus, and Mus musculus), the free-running period of the locomotor activity rhythm was similar whether the animals were exposed to continuous light or discrete light pulses occurring essentially only during the subjective night (i.e., feedback lighting). In the current experiments, feedback lighting was presented to squirrel monkeys so that light fell predominantly during the subjective night. Feedback lighting was linked to the drinking behavior in this diurnal primate so that when the animal drank, the lights went out. Despite the seemingly adverse predicament, the monkeys maintained regular circadian drinking rhythms. Furthermore, just as the period of the free-running activity rhythms of nocturnal rodents exposed to continuous light or feedback lighting were similar, the period of the drinking rhythms of the squirrel monkeys in continuous light and feedback lighting were comparable (25.6 +/- 0.1 and 25.9 +/- 0.1 hours, respectively), despite a substantial decrease in the total amount of light exposure associated with feedback lighting. The free-running period of monkeys exposed to continuous dark (24.5 +/- 0.1 hours) was significantly shorter than either of the two lighting conditions (P < 0.001). The results presented for the drinking rhythm were confirmed by examination of the temperature and activity rhythms. Therefore, discrete light pulses given predominately during the subjective night are capable of simulating the effects of continuous light on the free-running period of the circadian rhythms of a diurnal primate. The response of squirrel monkeys to feedback lighting thus lends further support for the model and suggests that the major entrainment mechanisms are similar in nocturnal rodents and diurnal primates.

Behavioral and physiological photoresponses to light intensity by intertidal microphytobenthos

NASA Astrophysics Data System (ADS)

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

2018-03-01

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 ( F v/ F m) 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 (rETR max), 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 F v/ F m under high light (500 and 100 μmol/(m2·s)) and prolonged illumination at 250 μmol/(m2·s), but did not significantly influence F v/ F m under 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 rETR max) than migratory MPB under light intensities above 250 μmol/(m2·s) after 4.0 h illumination.

Bright light induces choroidal thickening in chickens.

PubMed

Lan, Weizhong; Feldkaemper, Marita; Schaeffel, Frank

2013-11-01

Bright light is a potent inhibitor of myopia development in animal models. Because development of refractive errors has been linked to changes in choroidal thickness, we have studied in chickens whether bright light may exert its effects on myopia also through changes in choroidal thickness. Three-day-old chickens were exposed to "bright light" (15,000 lux; n = 14) from 10 AM to 4 PM but kept under "normal light" (500 lux) during the remaining time of the light phase for 5 days (total duration of light phase 8 AM to 6 PM). A control group (n = 14) was kept under normal light during the entire light phase. Choroidal thickness was measured in alert, hand-held animals with optical coherence tomography at 10 AM, 4 PM, and 8 PM every day. Complete data sets were available for 12 chicks in bright light group and nine in normal light group. The striking inter-individual variability in choroidal thickness (coefficient of variance: 23%) made it necessary to normalize changes to the individual baseline thickness of the choroid. During the 6 hours of exposure to bright light, choroidal thickness decreased by -5.2 ± 4.0% (mean ± SEM). By contrast, in the group kept under normal light, choroidal thickness increased by +15.4 ± 4.7% (difference between both groups p = 0.003). After an additional 4 hours, choroidal thickness increased also in the "bright light group" by +17.8 ± 3.5%, while there was little further change (+0.6 ± 4.0%) in the "normal light group" (difference p = 0.004). Finally, the choroid was thicker in the "bright light group" (+7.6 ± 26.0%) than in the "normal light group" (day 5: -18.6 ± 26.9%; difference p = 0.036). Bright light stimulates choroidal thickening in chickens, although the response is smaller than with experimentally imposed myopic defocus, and it occurs with some time delay. It nevertheless suggests that choroidal thickening is also involved in myopia inhibition by bright light.

Light Emitting Diodes and Astronomy - a chance for restoration of the dark night sky - or for further loss

NASA Astrophysics Data System (ADS)

Wainscoat, Richard

2015-08-01

Across the planet, conventional light sources such as high pressure sodium, are rapidly being replaced by light emitting diodes (LEDs). As light fixtures are being replaced, there is a tremendous opportunity for restoration of dark night skies through replacement of poorly shielded fixtures by fully shielded fixtures. However, it is critically important to limit the amount of blue light from the LEDs.Sales people are strongly promoting LEDs with high correlated color temperature (CCT), such as 5000K. They are promoting them on energy efficiency grounds - higher energy efficiency is easier to sell. These LEDs have tremendous amounts of blue light near 450 nm. The photopic human eye is relatively insensitive to this blue light, but the dark adapted scotopic eye is much more sensitive, and CCDs are also very sensitive to this wavelength of light. As a consequence, both professional and amateur astronomers are very seriously impacted by high CCT LED lighting. The sodium lighting that the LEDs are replacing has relatively little blue light. Blue light is strongly scattered by air molecules in the atmosphere.Use of high CCT LED lighting will cause further deterioration of night sky quality.In contrast, use of LED lighting with low CCT (e.g., 2400K or 2700K), or use of filters to remove the blue light, can restore the dark night sky. LED lighting is much easier to direct, meaning that an area such as a roadway can be lit with many less lumens with LEDs compared to conventional lights such as high pressure sodium. And use of fully shielded fixtures will eliminate direct uplighting.It is therefore critically important at this time to require that all new LED lighting be fully shielded, and for strong limits to be placed the amount of blue light from LEDs. This is crucial near observatories, but is important everywhere.

Light quality influences the virulence and physiological responses of Colletotrichum acutatum causing anthracnose in pepper plants.

PubMed

Yu, S-M; Ramkumar, G; Lee, Y H

2013-08-01

To explore the effects of light quality on the physiology and pathogenicity of Colletotrichum acutatum, we analysed the morphological traits, melanin production and virulence of the pathogen under different light wavelengths. The influence of light wavelength on the mycelial growth and conidial germination of C. acutatum was investigated using red, green, blue and white light sources. Red and green light reduced the mycelial growth in comparison with blue and white light, and dark conditions. The least percentage of conidial germination was observed under blue light, while the germination rate among white, red and green light, as well as in the dark, was insignificant. In comparison with its influence on mycelial growth and conidial germination, light wavelength significantly affected the pathogen's virulence towards hot pepper fruits. The highest disease severity was observed under blue light, which was at least a twofold increase compared with the disease severity under other light conditions. To elucidate the effect of light on the disparity in virulence, scytalone was assayed by HPLC, and scd1 gene expression was examined with real-time PCR. The highest and lowest scytalone production was observed in the cultures incubated under blue (10.9 mAU) and green light (1.5 mAU), respectively. Higher scd1 gene expression (~ 40-fold increase) was observed in cultures incubated under blue and white light in comparison with those incubated in the dark. This study revealed that light affects the growth, colonial morphology and virulence of C. acutatum. The pathogen needs light for its active melanin production and also to attain higher virulence. This is the first report on the effect of light quality on the virulence of C. acutatum. The findings of this study will broaden our knowledge of the influence of light on physiological responses of fungal pathogens. © 2013 The Society for Applied Microbiology.

Optimisation approaches for concurrent transmitted light imaging during confocal microscopy.

PubMed

Collings, David A

2015-01-01

The transmitted light detectors present on most modern confocal microscopes are an under-utilised tool for the live imaging of plant cells. As the light forming the image in this detector is not passed through a pinhole, out-of-focus light is not removed. It is this extended focus that allows the transmitted light image to provide cellular and organismal context for fluorescence optical sections generated confocally. More importantly, the transmitted light detector provides images that have spatial and temporal registration with the fluorescence images, unlike images taken with a separately-mounted camera. Because plants often provide difficulties for taking transmitted light images, with the presence of pigments and air pockets in leaves, this study documents several approaches to improving transmitted light images beginning with ensuring that the light paths through the microscope are correctly aligned (Köhler illumination). Pigmented samples can be imaged in real colour using sequential scanning with red, green and blue lasers. The resulting transmitted light images can be optimised and merged in ImageJ to generate colour images that maintain registration with concurrent fluorescence images. For faster imaging of pigmented samples, transmitted light images can be formed with non-absorbed wavelengths. Transmitted light images of Arabidopsis leaves expressing GFP can be improved by concurrent illumination with green and blue light. If the blue light used for YFP excitation is blocked from the transmitted light detector with a cheap, coloured glass filters, the non-absorbed green light will form an improved transmitted light image. Changes in sample colour can be quantified by transmitted light imaging. This has been documented in red onion epidermal cells where changes in vacuolar pH triggered by the weak base methylamine result in measurable colour changes in the vacuolar anthocyanin. Many plant cells contain visible levels of pigment. The transmitted light detector provides a useful tool for documenting and measuring changes in these pigments while maintaining registration with confocal imaging.

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

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-12

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-71,767] General Electric Lighting-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...

33 CFR 127.109 - Lighting systems.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Lighting systems. 127.109 Section... Waterfront Facilities Handling Liquefied Natural Gas § 127.109 Lighting systems. (a) The marine transfer area for LNG must have a lighting system and separate emergency lighting. (b) All outdoor lighting must be...

33 CFR 127.109 - Lighting systems.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Lighting systems. 127.109 Section... Waterfront Facilities Handling Liquefied Natural Gas § 127.109 Lighting systems. (a) The marine transfer area for LNG must have a lighting system and separate emergency lighting. (b) All outdoor lighting must be...

33 CFR 127.109 - Lighting systems.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Lighting systems. 127.109 Section... Waterfront Facilities Handling Liquefied Natural Gas § 127.109 Lighting systems. (a) The marine transfer area for LNG must have a lighting system and separate emergency lighting. (b) All outdoor lighting must be...

33 CFR 127.109 - Lighting systems.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Lighting systems. 127.109 Section... Waterfront Facilities Handling Liquefied Natural Gas § 127.109 Lighting systems. (a) The marine transfer area for LNG must have a lighting system and separate emergency lighting. (b) All outdoor lighting must be...

33 CFR 127.109 - Lighting systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Lighting systems. 127.109 Section... Waterfront Facilities Handling Liquefied Natural Gas § 127.109 Lighting systems. (a) The marine transfer area for LNG must have a lighting system and separate emergency lighting. (b) All outdoor lighting must be...

33 CFR 67.05-10 - Characteristics of obstruction lights.

Code of Federal Regulations, 2010 CFR

2010-07-01

... lights. 67.05-10 Section 67.05-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Requirements for Lights § 67.05-10 Characteristics of obstruction lights. All obstruction lights required by... marking Class “C” structures. In determining whether white or red lights shall be authorized, the District...

14 CFR 27.1383 - Landing lights.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing lights. 27.1383 Section 27.1383... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1383 Landing lights. (a) Each required landing or hovering light must be approved. (b) Each landing light must be installed so that— (1) No...

49 CFR 230.87 - Cab lights.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Cab lights. 230.87 Section 230.87 Transportation... Signals, Sanders and Lights § 230.87 Cab lights. Each steam locomotive shall have cab lights that... readings from their usual and proper positions in the cab. These lights shall be so located and constructed...

46 CFR 183.420 - Navigation lights.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Navigation lights. 183.420 Section 183.420 Shipping...) ELECTRICAL INSTALLATION Lighting Systems § 183.420 Navigation lights. All vessels must have navigation lights..., except that a vessel of more than 19.8 meters (65 feet) in length must also have navigation lights that...

14 CFR 25.1383 - Landing lights.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing lights. 25.1383 Section 25.1383... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1383 Landing lights. (a) Each landing light...) The pilot is not adversely affected by halation; and (3) It provides enough light for night landing...

33 CFR 67.05-5 - Multiple obstruction lights.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Multiple obstruction lights. 67... for Lights § 67.05-5 Multiple obstruction lights. When more than one obstruction light is required by this part to mark a structure, all such lights shall be operated to flash in unison. ...

46 CFR 183.430 - Portable lights

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Portable lights 183.430 Section 183.430 Shipping COAST...) ELECTRICAL INSTALLATION Lighting Systems § 183.430 Portable lights Each vessel must be equipped with at least two operable portable battery lights. One of these lights must be located at the operating station and...

14 CFR 29.1383 - Landing lights.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing lights. 29.1383 Section 29.1383... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1383 Landing lights. (a) Each required landing or hovering light must be approved. (b) Each landing light must be installed so that— (1) No...

49 CFR 230.87 - Cab lights.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Cab lights. 230.87 Section 230.87 Transportation... Signals, Sanders and Lights § 230.87 Cab lights. Each steam locomotive shall have cab lights that... readings from their usual and proper positions in the cab. These lights shall be so located and constructed...

33 CFR 67.05-5 - Multiple obstruction lights.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Multiple obstruction lights. 67... for Lights § 67.05-5 Multiple obstruction lights. When more than one obstruction light is required by this part to mark a structure, all such lights shall be operated to flash in unison. ...

46 CFR 183.420 - Navigation lights.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Navigation lights. 183.420 Section 183.420 Shipping...) ELECTRICAL INSTALLATION Lighting Systems § 183.420 Navigation lights. All vessels must have navigation lights..., except that a vessel of more than 19.8 meters (65 feet) in length must also have navigation lights that...

46 CFR 183.420 - Navigation lights.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Navigation lights. 183.420 Section 183.420 Shipping...) ELECTRICAL INSTALLATION Lighting Systems § 183.420 Navigation lights. All vessels must have navigation lights..., except that a vessel of more than 19.8 meters (65 feet) in length must also have navigation lights that...

33 CFR 67.05-10 - Characteristics of obstruction lights.

Code of Federal Regulations, 2013 CFR

2013-07-01

... lights. 67.05-10 Section 67.05-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Requirements for Lights § 67.05-10 Characteristics of obstruction lights. All obstruction lights required by... marking Class “C” structures. In determining whether white or red lights shall be authorized, the District...

14 CFR 29.1383 - Landing lights.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Landing lights. 29.1383 Section 29.1383... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1383 Landing lights. (a) Each required landing or hovering light must be approved. (b) Each landing light must be installed so that— (1) No...

49 CFR 230.87 - Cab lights.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Cab lights. 230.87 Section 230.87 Transportation... Signals, Sanders and Lights § 230.87 Cab lights. Each steam locomotive shall have cab lights that... readings from their usual and proper positions in the cab. These lights shall be so located and constructed...

33 CFR 67.05-10 - Characteristics of obstruction lights.

Code of Federal Regulations, 2014 CFR

2014-07-01

... lights. 67.05-10 Section 67.05-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Requirements for Lights § 67.05-10 Characteristics of obstruction lights. All obstruction lights required by... marking Class “C” structures. In determining whether white or red lights shall be authorized, the District...

46 CFR 183.420 - Navigation lights.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Navigation lights. 183.420 Section 183.420 Shipping...) ELECTRICAL INSTALLATION Lighting Systems § 183.420 Navigation lights. All vessels must have navigation lights..., except that a vessel of more than 19.8 meters (65 feet) in length must also have navigation lights that...

49 CFR 230.87 - Cab lights.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Cab lights. 230.87 Section 230.87 Transportation... Signals, Sanders and Lights § 230.87 Cab lights. Each steam locomotive shall have cab lights that... readings from their usual and proper positions in the cab. These lights shall be so located and constructed...

14 CFR 27.1383 - Landing lights.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Landing lights. 27.1383 Section 27.1383... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1383 Landing lights. (a) Each required landing or hovering light must be approved. (b) Each landing light must be installed so that— (1) No...

46 CFR 183.430 - Portable lights

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Portable lights 183.430 Section 183.430 Shipping COAST...) ELECTRICAL INSTALLATION Lighting Systems § 183.430 Portable lights Each vessel must be equipped with at least two operable portable battery lights. One of these lights must be located at the operating station and...

33 CFR 67.05-5 - Multiple obstruction lights.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Multiple obstruction lights. 67... for Lights § 67.05-5 Multiple obstruction lights. When more than one obstruction light is required by this part to mark a structure, all such lights shall be operated to flash in unison. ...

46 CFR 183.430 - Portable lights

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Portable lights 183.430 Section 183.430 Shipping COAST...) ELECTRICAL INSTALLATION Lighting Systems § 183.430 Portable lights Each vessel must be equipped with at least two operable portable battery lights. One of these lights must be located at the operating station and...

14 CFR 25.1383 - Landing lights.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Landing lights. 25.1383 Section 25.1383... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1383 Landing lights. (a) Each landing light...) The pilot is not adversely affected by halation; and (3) It provides enough light for night landing...

14 CFR 29.1383 - Landing lights.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Landing lights. 29.1383 Section 29.1383... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1383 Landing lights. (a) Each required landing or hovering light must be approved. (b) Each landing light must be installed so that— (1) No...

46 CFR 183.430 - Portable lights

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Portable lights 183.430 Section 183.430 Shipping COAST...) ELECTRICAL INSTALLATION Lighting Systems § 183.430 Portable lights Each vessel must be equipped with at least two operable portable battery lights. One of these lights must be located at the operating station and...

49 CFR 230.87 - Cab lights.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Cab lights. 230.87 Section 230.87 Transportation... Signals, Sanders and Lights § 230.87 Cab lights. Each steam locomotive shall have cab lights that... readings from their usual and proper positions in the cab. These lights shall be so located and constructed...

33 CFR 67.05-10 - Characteristics of obstruction lights.

Code of Federal Regulations, 2011 CFR

2011-07-01

... lights. 67.05-10 Section 67.05-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Requirements for Lights § 67.05-10 Characteristics of obstruction lights. All obstruction lights required by... marking Class “C” structures. In determining whether white or red lights shall be authorized, the District...

46 CFR 183.420 - Navigation lights.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Navigation lights. 183.420 Section 183.420 Shipping...) ELECTRICAL INSTALLATION Lighting Systems § 183.420 Navigation lights. All vessels must have navigation lights..., except that a vessel of more than 19.8 meters (65 feet) in length must also have navigation lights that...

46 CFR 183.430 - Portable lights

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Portable lights 183.430 Section 183.430 Shipping COAST...) ELECTRICAL INSTALLATION Lighting Systems § 183.430 Portable lights Each vessel must be equipped with at least two operable portable battery lights. One of these lights must be located at the operating station and...

14 CFR 29.1383 - Landing lights.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Landing lights. 29.1383 Section 29.1383... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1383 Landing lights. (a) Each required landing or hovering light must be approved. (b) Each landing light must be installed so that— (1) No...

14 CFR 25.1383 - Landing lights.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Landing lights. 25.1383 Section 25.1383... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1383 Landing lights. (a) Each landing light...) The pilot is not adversely affected by halation; and (3) It provides enough light for night landing...

33 CFR 67.05-5 - Multiple obstruction lights.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Multiple obstruction lights. 67... for Lights § 67.05-5 Multiple obstruction lights. When more than one obstruction light is required by this part to mark a structure, all such lights shall be operated to flash in unison. ...

33 CFR 67.05-5 - Multiple obstruction lights.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Multiple obstruction lights. 67... for Lights § 67.05-5 Multiple obstruction lights. When more than one obstruction light is required by this part to mark a structure, all such lights shall be operated to flash in unison. ...

14 CFR 27.1383 - Landing lights.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Landing lights. 27.1383 Section 27.1383... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1383 Landing lights. (a) Each required landing or hovering light must be approved. (b) Each landing light must be installed so that— (1) No...

33 CFR 67.05-10 - Characteristics of obstruction lights.

Code of Federal Regulations, 2012 CFR

2012-07-01

... lights. 67.05-10 Section 67.05-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Requirements for Lights § 67.05-10 Characteristics of obstruction lights. All obstruction lights required by... marking Class “C” structures. In determining whether white or red lights shall be authorized, the District...

14 CFR 29.1383 - Landing lights.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Landing lights. 29.1383 Section 29.1383... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1383 Landing lights. (a) Each required landing or hovering light must be approved. (b) Each landing light must be installed so that— (1) No...

14 CFR 27.1383 - Landing lights.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Landing lights. 27.1383 Section 27.1383... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1383 Landing lights. (a) Each required landing or hovering light must be approved. (b) Each landing light must be installed so that— (1) No...

14 CFR 27.1383 - Landing lights.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Landing lights. 27.1383 Section 27.1383... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1383 Landing lights. (a) Each required landing or hovering light must be approved. (b) Each landing light must be installed so that— (1) No...

14 CFR 25.1383 - Landing lights.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Landing lights. 25.1383 Section 25.1383... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1383 Landing lights. (a) Each landing light...) The pilot is not adversely affected by halation; and (3) It provides enough light for night landing...

14 CFR 25.1383 - Landing lights.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Landing lights. 25.1383 Section 25.1383... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1383 Landing lights. (a) Each landing light...) The pilot is not adversely affected by halation; and (3) It provides enough light for night landing...

Integrated LED-based luminaire for general lighting

DOEpatents

Dowling, Kevin J.; Lys, Ihor A.; Williamson, Ryan C.; Roberge, Brian; Roberts, Ron; Morgan, Frederick; Datta, Michael Jay; Mollnow, Tomas Jonathan

2016-08-30

Lighting apparatus and methods employing LED light sources are described. The LED light sources are integrated with other components in the form of a luminaire or other general purpose lighting structure. Some of the lighting structures are formed as Parabolic Aluminum Reflector (PAR) luminaires, allowing them to be inserted into conventional sockets. The lighting structures display beneficial operating characteristics, such as efficient operation, high thermal dissipation, high output, and good color mixing.

Integrated LED-based luminare for general lighting

DOEpatents

Dowling, Kevin J.; Lys, Ihor A.; Roberge, Brian; Williamson, Ryan C.; Roberts, Ron; Datta, Michael; Mollnow, Tomas; Morgan, Frederick M.

2013-03-05

Lighting apparatus and methods employing LED light sources are described. The LED light sources are integrated with other components in the form of a luminaire or other general purpose lighting structure. Some of the lighting structures are formed as Parabolic Aluminum Reflector (PAR) luminaires, allowing them to be inserted into conventional sockets. The lighting structures display beneficial operating characteristics, such as efficient operation, high thermal dissipation, high output, and good color mixing.

Northern Red Oak Seedling Growth Varies by Light Intensity and Seed Source

Treesearch

Charles E. McGee

1968-01-01

Northern red oak seedlings from each of three seed sources were subjected for one growing season to one of four intensities of light: full light, 70 percent light, 37 percent light, and 8 percent light. Seedlings grown in the open were taller than those grown in the shade and had more, generally heavier leaves. Height and leaf growth decreased as the amount of light...

Method and apparatus for wavefront sensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bahk, Seung-Whan

A method for performing optical wavefront sensing includes providing an amplitude transmission mask having a light input side, a light output side, and an optical transmission axis passing from the light input side to the light output side. The amplitude transmission mask is characterized by a checkerboard pattern having a square unit cell of size .LAMBDA.. The method also includes directing an incident light field having a wavelengthmore » $$ \\lamda $$ to be incident on the light input side and propagating the incident light field through the amplitude transmission mask. The method further includes producing a plurality of diffracted light fields on the light output side and detecting, at a detector disposed a distance L from the amplitude transmission mask, an interferogram associated with the plurality of diffracted light fields.« less

Advantages of diffuse light for horticultural production and perspectives for further research

PubMed Central

Li, Tao; Yang, Qichang

2015-01-01

Plants use diffuse light more efficiently than direct light, which is well established due to diffuse light penetrates deeper into the canopy and photosynthetic rate of a single leaf shows a non-linear response to the light flux density. Diffuse light also results in a more even horizontal and temporal light distribution in the canopy, which plays substantial role for crop photosynthesis enhancement as well as production improvement. Here we show some of the recent findings about the effect of diffuse light on light distribution over the canopy and its direct and indirect effects on crop photosynthesis and plant growth, and suggest some perspectives for further research which could strengthen the scientific understanding of diffuse light modulate plant processes and its application in horticultural production. PMID:26388890

Room-temperature quantum noise limited spectrometry and methods of the same

DOEpatents

Stevens, Charles G.; Tringe, Joseph W.; Cunningham, Christopher Thomas

2014-08-26

In one embodiment, a heterodyne detection system for detecting light includes a first input aperture adapted for receiving first light from a scene input, a second input aperture adapted for receiving second light from a local oscillator input, a broadband local oscillator adapted for providing the second light to the second input aperture, a dispersive element adapted for dispersing the first light and the second light, and a final condensing lens coupled to an infrared detector. The final condensing lens is adapted for concentrating incident light from a primary condensing lens onto the infrared detector, and the infrared detector is a square-law detector capable of sensing the frequency difference between the first light and the second light. More systems and methods for detecting light are described according to other embodiments.

Room-temperature quantum noise limited spectrometry and methods of the same

DOEpatents

Stevens, Charles G; Tringe, Joseph W

2014-12-02

In one embodiment, a heterodyne detection system for detecting light includes a first input aperture adapted for receiving a first light from a scene input, a second input aperture adapted for receiving a second light from a local oscillator input, a broadband local oscillator adapted for providing the second light to the second input aperture, a dispersive element adapted for dispersing the first light and the second light, and a final condensing lens coupled to an infrared detector. The final condensing lens is adapted for concentrating incident light from a primary condensing lens onto the detector, and the detector is a square-law detector capable of sensing the frequency difference between the first light and the second light. More systems and methods for detecting light are disclosed according to more embodiments.

Room-temperature quantum noise limited spectrometry and methods of the same

DOEpatents

Stevens, Charles G.; Tringe, Joseph W.; Cunningham, Christopher T.

2016-08-02

In one embodiment, a heterodyne detection system for detecting light includes a first input aperture configured to receive first light from a scene input, a second input aperture configured to receive second light from a local oscillator input, a broadband local oscillator configured to provide the second light to the second input aperture, a dispersive element configured to disperse the first light and the second light, and a final condensing lens coupled to an infrared detector. The final condensing lens is configured to concentrate incident light from a primary condensing lens onto the infrared detector, and the infrared detector is a square-law detector capable of sensing the frequency difference between the first light and the second light. More systems and methods for detecting light are described according to other embodiments.

Dim Light at Night Increases Body Mass of Female Mice

PubMed Central

Aubrecht, Taryn G.; Jenkins, Richelle; Nelson, Randy J.

2016-01-01

During the past century the prevalence of light at night has increased in parallel with obesity rates. Dim light at night (dLAN) increases body mass in male mice. However, the effects of light at night on female body mass remain unspecified. Thus, female mice were exposed to a standard light/dark (LD; 16h light at ~150 lux/8h dark at ~0 lux) cycle or to light/dim light at night (dLAN; 16h light at ~150 lux/8h dim light at ~5 lux) cycles for six weeks. Females exposed to dLAN increased the rate of change in body mass compared to LD mice despite reduced total food intake during weeks five and six, suggesting that dLAN disrupted circadian rhythms resulting in deranged metabolism. PMID:25431079

Red Light Represses the Photophysiology of the Scleractinian Coral Stylophora pistillata

PubMed Central

Wijgerde, Tim; van Melis, Anne; Silva, Catarina I. F.; Leal, Miguel C.; Vogels, Luc; Mutter, Claudia; Osinga, Ronald

2014-01-01

Light spectrum plays a key role in the biology of symbiotic corals, with blue light resulting in higher coral growth, zooxanthellae density, chlorophyll a content and photosynthesis rates as compared to red light. However, it is still unclear whether these physiological processes are blue-enhanced or red-repressed. This study investigated the individual and combined effects of blue and red light on the health, zooxanthellae density, photophysiology and colouration of the scleractinian coral Stylophora pistillata over 6 weeks. Coral fragments were exposed to blue, red, and combined 50/50% blue red light, at two irradiance levels (128 and 256 μmol m−2 s−1). Light spectrum affected the health/survival, zooxanthellae density, and NDVI (a proxy for chlorophyll a content) of S. pistillata. Blue light resulted in highest survival rates, whereas red light resulted in low survival at 256 μmol m−2 s−1. Blue light also resulted in higher zooxanthellae densities compared to red light at 256 μmol m−2 s−1, and a higher NDVI compared to red and combined blue red light. Overall, our results suggest that red light negatively affects the health, survival, symbiont density and NDVI of S. pistillata, with a dominance of red over blue light for NDVI. PMID:24658108

Exploring the relationship between patient call-light use rate and nurse call-light response time in acute care settings.

PubMed

Tzeng, Huey-Ming; Larson, Janet L

2011-03-01

Patient call-light usage and nurse responsiveness to call lights are two intertwined concepts that could affect patients' safety during hospital stays. Little is known about the relationship between call-light usage and call-light response time. Consequently, this exploratory study examined the relationship between the patient-initiated call-light use rate and the nursing staff's average call-light response time in a Michigan community hospital. It used hospital archived data retrieved from the call-light tracking system for the period from February 2007 through June 2008. Curve estimation regression and multiple regression analyses were conducted. The results showed that the call-light response time was not affected by the total nursing hours or RN hours. The nurse call-light response time was longer when the patient call-light use rate was higher and the average length of stay was shorter. It is likely that a shorter length of stay contributes to the nursing care activity level on the unit because it is associated with a higher frequency of patient admissions/discharges and treatment per patient-day. This suggests that the nursing care activity level on the unit and number of call-light alarms could affect nurse call-light response time, independently of the number of nurses available to respond.

Application of growth-phase based light-feeding strategies to simultaneously enhance Chlorella vulgaris growth and lipid accumulation.

PubMed

Sun, Yahui; Liao, Qiang; Huang, Yun; Xia, Ao; Fu, Qian; Zhu, Xun; Fu, Jingwei; Li, Jun

2018-05-01

Considering the variations of optimal light intensity required by microalgae cells along with growth phases, growth-phase light-feeding strategies were proposed and verified in this paper, aiming at boosting microalgae lipid productivity from the perspective of light conditions optimization. Experimental results demonstrate that under an identical time-averaged light intensity, the light-feeding strategies characterized by stepwise incremental light intensities showed a positive effect on biomass and lipid accumulation. The lipid productivity (235.49 mg L -1  d -1 ) attained under light-feeding strategy V (time-averaged light intensity: 225 μmol m -2  s -1 ) was 52.38% higher over that obtained under a constant light intensity of 225 μmol m -2  s -1 . Subsequently, based on light-feeding strategy V, microalgae lipid productivity was further elevated to 312.92 mg L -1  d -1 employing a two-stage based light-feeding strategy V 560 (time-averaged light intensity: 360 μmol m -2  s -1 ), which was 79.63% higher relative to that achieved under a constant light intensity of 360 μmol m -2  s -1 . Copyright © 2018 Elsevier Ltd. All rights reserved.

Behavioural responses of krill and cod to artificial light in laboratory experiments

PubMed Central

Løkkeborg, S.; Humborstad, O-B.

2018-01-01

Most fishes and crustaceans respond to light, and artificial light sources may therefore be an efficient stimulus to manipulate behaviours in aquatic animals. It has been hypothesised that the catch efficiency of pots could be increased if prey, for example krill, can be attracted into the pots providing a visual stimulus and a source of live bait. To find which light characteristics are most attractive to krill, we tested the effects of light intensity and wavelength composition on Northern krill’s (Meganyctiphanes norvegica) behavioural response to an artificial light source. The most attractive individual wavelength was 530 nm (green light), while broadband (425–750 nm) white light was an equally attractive light source. The intensity of the emitted light did not appear to have a direct effect on attraction to the light source, however it did significantly increase swimming activity among the observed krill. The most promising light stimuli for krill were tested to determine whether they would have a repulsive or attractive effect on cod (Gadus morhua); These light stimuli appeared to have a slightly repulsive, but non-significant, effect on cod. However, we suggest that a swarm of krill attracted to an artificial light source may produce a more effective visual stimulus to foraging cod. PMID:29370231

Bright versus dim ambient light affects subjective well-being but not serotonin-related biological factors.

PubMed

Stemer, Bettina; Melmer, Andreas; Fuchs, Dietmar; Ebenbichler, Christoph; Kemmler, Georg; Deisenhammer, Eberhard A

2015-10-30

Light falling on the retina is converted into an electrical signal which stimulates serotonin synthesis. Previous studies described an increase of plasma and CNS serotonin levels after bright light exposure. Ghrelin and leptin are peptide hormones which are involved in the regulation of hunger/satiety and are related to serotonin. Neopterin and kynurenine are immunological markers which are also linked to serotonin biosynthesis. In this study, 29 healthy male volunteers were exposed to bright (5000lx) and dim (50lx) light conditions for 120min in a cross-over manner. Subjective well-being and hunger as well as various serotonin associated plasma factors were assessed before and after light exposure. Subjective well-being showed a small increase under bright light and a small decrease under dim light, resulting in a significant interaction between light condition and time. Ghrelin concentrations increased significantly under both light conditions, but there was no interaction between light and time. Correspondingly, leptin decreased significantly under both light conditions. Hunger increased significantly with no light-time interaction. We also found a significant decrease of neopterin, tryptophan and tyrosine levels, but no interaction between light and time. In conclusion, ambient light was affecting subjective well-being rather than serotonin associated biological factors. Copyright © 2015. Published by Elsevier Ireland Ltd.

LED Light Characteristics for Surgical Shadowless Lamps and Surgical Loupes

PubMed Central

Kinugawa, Yoshitaka; Nobae, Yuichi; Suzuki, Toshihiro; Tanaka, Yoshiyuki; Toda, Ikuko; Tsubota, Kazuo

2015-01-01

Background: Blue light has more energy than longer wavelength light and can penetrate the eye to reach the retina. When surgeons use magnifying loupes under intensive surgical shadowless lamps for better view of the surgical field, the total luminance is about 200 times brighter than that of typical office lighting. In this study, the effects of 2 types of shadowless lamps were compared. Moreover, the effect of various eyeglasses, which support magnifying loupes, on both the light energy and color rendering was considered. Methods: The light intensity and color rendering were measured on 3 variables: light transmittance, light intensity, and color rendering. Results: Under shadowless lamps, the light energy increased with low-magnification loupes and decreased with high-magnification loupes. Filtering eyeglasses reduced the energy, especially in conditions where the low-magnification loupe was used. The best color-rendering index values were obtained with computer eyeglasses under conventional light-emitting diode shadowless lamps and with no glass and with lightly yellow-tinted lenses under less-blue light-emitting diode. Conclusions: Microsurgeons are exposed to strong lighting throughout their career, and proper color rendering must be considered for easier recognition. Light toxicity and loss of color rendering can be reduced with an appropriate combination of shadowless lamps and colored eyeglasses. PMID:26893987

Red light represses the photophysiology of the scleractinian coral Stylophora pistillata.

PubMed

Wijgerde, Tim; van Melis, Anne; Silva, Catarina I F; Leal, Miguel C; Vogels, Luc; Mutter, Claudia; Osinga, Ronald

2014-01-01

Light spectrum plays a key role in the biology of symbiotic corals, with blue light resulting in higher coral growth, zooxanthellae density, chlorophyll a content and photosynthesis rates as compared to red light. However, it is still unclear whether these physiological processes are blue-enhanced or red-repressed. This study investigated the individual and combined effects of blue and red light on the health, zooxanthellae density, photophysiology and colouration of the scleractinian coral Stylophora pistillata over 6 weeks. Coral fragments were exposed to blue, red, and combined 50/50% blue red light, at two irradiance levels (128 and 256 μmol m(-2) s(-1)). Light spectrum affected the health/survival, zooxanthellae density, and NDVI (a proxy for chlorophyll a content) of S. pistillata. Blue light resulted in highest survival rates, whereas red light resulted in low survival at 256 μmol m(-2) s(-1). Blue light also resulted in higher zooxanthellae densities compared to red light at 256 μmol m(-2) s(-1), and a higher NDVI compared to red and combined blue red light. Overall, our results suggest that red light negatively affects the health, survival, symbiont density and NDVI of S. pistillata, with a dominance of red over blue light for NDVI.

Behavioural responses of krill and cod to artificial light in laboratory experiments.

PubMed

Utne-Palm, A C; Breen, M; Løkkeborg, S; Humborstad, O-B

2018-01-01

Most fishes and crustaceans respond to light, and artificial light sources may therefore be an efficient stimulus to manipulate behaviours in aquatic animals. It has been hypothesised that the catch efficiency of pots could be increased if prey, for example krill, can be attracted into the pots providing a visual stimulus and a source of live bait. To find which light characteristics are most attractive to krill, we tested the effects of light intensity and wavelength composition on Northern krill's (Meganyctiphanes norvegica) behavioural response to an artificial light source. The most attractive individual wavelength was 530 nm (green light), while broadband (425-750 nm) white light was an equally attractive light source. The intensity of the emitted light did not appear to have a direct effect on attraction to the light source, however it did significantly increase swimming activity among the observed krill. The most promising light stimuli for krill were tested to determine whether they would have a repulsive or attractive effect on cod (Gadus morhua); These light stimuli appeared to have a slightly repulsive, but non-significant, effect on cod. However, we suggest that a swarm of krill attracted to an artificial light source may produce a more effective visual stimulus to foraging cod.

Far-red light is needed for efficient photochemistry and photosynthesis.

PubMed

Zhen, Shuyang; van Iersel, Marc W

2017-02-01

The efficiency of monochromatic light to drive photosynthesis drops rapidly at wavelengths longer than 685nm. The photosynthetic efficiency of these longer wavelengths can be improved by adding shorter wavelength light, a phenomenon known as the Emerson enhancement effect. The reverse effect, the enhancement of photosynthesis under shorter wavelength light by longer wavelengths, however, has not been well studied and is often thought to be insignificant. We quantified the effect of adding far-red light (peak at 735nm) to red/blue or warm-white light on the photosynthetic efficiency of lettuce (Lactuca sativa). Adding far-red light immediately increased quantum yield of photosystem II (Φ PSII ) of lettuce by an average of 6.5 and 3.6% under red/blue and warm-white light, respectively. Similar or greater increases in Φ PSII were observed after 20min of exposure to far-red light. This longer-term effect of far-red light on Φ PSII was accompanied by a reduction in non-photochemical quenching of fluorescence (NPQ), indicating that far-red light reduced the dissipation of absorbed light as heat. The increase in Φ PSII and complementary decrease in NPQ is presumably due to preferential excitation of photosystem I (PSI) by far-red light, which leads to faster re-oxidization of the plastoquinone pool. This facilitates reopening of PSII reaction centers, enabling them to use absorbed photons more efficiently. The increase in Φ PSII by far-red light was associated with an increase in net photosynthesis (P n ). The stimulatory effect of far-red light increased asymptotically with increasing amounts of far-red. Overall, our results show that far-red light can increase the photosynthetic efficiency of shorter wavelength light that over-excites PSII. Copyright © 2016 Elsevier GmbH. All rights reserved.

The effect of infection-control barriers on the light intensity of light-cure units and depth of cure of composite.

PubMed

Hodson, Nicholas A; Dunne, Stephen M; Pankhurst, Caroline L

2005-04-01

Dental curing lights are vulnerable to contamination with oral fluids during routine intra-oral use. This controlled study aimed to evaluate whether or not disposable transparent barriers placed over the light-guide tip would affect light output intensity or the subsequent depth of cure of a composite restoration. The impact on light intensity emitted from high-, medium- and low-output light-cure units in the presence of two commercially available disposable infection-control barriers was evaluated against a no-barrier control. Power density measurements from the three intensity light-cure units were recorded with a radiometer, then converted to a digital image using an intra-oral camera and values determined using a commercial computer program. For each curing unit, the measurements were repeated on ten separate occasions with each barrier and the control. Depth of cure was evaluated using a scrape test in a natural tooth model. At each level of light output, the two disposable barriers produced a significant reduction in the mean power density readings compared to the no-barrier control (P<0.005). The cure sleeve inhibited light output to a greater extent than either the cling film or the control (P<0.005). Only composite restorations light-activated by the high level unit demonstrated a small but significant decrease in the depth of cure compared to the control (P<0.05). Placing disposable barriers over the light-guide tip reduced the light intensity from all three curing lights. There was no impact on depth of cure except for the high-output light, where a small decrease in cure depth was noted but this was not considered clinically significant. Disposable barriers can be recommended for use with light-cure lights.

Recreating the shading effects of ship wake induced turbidity to test acclimation responses in the seagrass Thalassia hemprichii

NASA Astrophysics Data System (ADS)

Browne, Nicola K.; Yaakub, Siti Maryam; Tay, Jason K. L.; Todd, Peter A.

2017-12-01

Elevated sediment delivery and resuspension in coastal waters from human activities such as shipping can have detrimental effects on seagrass health by limiting light penetration. Managing seagrasses requires knowledge of their light acclamatory abilities so guidelines for coastal activities (e.g. ship movements) that influence sediment dynamics can be created. Guidelines typically focus on ensuring that seagrasses are able to meet their minimal light requirements (MLR). MLRs can be achieved by different light regimes, but it remains unknown whether a chronically low yet stable light regime is less or more detrimental than a highly variable regime with periods of extreme low to no light. To test this, we compared the physiological and morphological responses of Thalassia hemprichii among three light regimes: an open control (30-40% ambient light), a shaded control with (11-15% ambient light), and a fluctuating shade (4-30% ambient light). The MLR for the T. hemprichii we studied was lower (4-10% ambient light) than previous reports (mean = 18%) illustrating enhanced light acclimation in Singapore's chronically turbid waters. Seagrass shoots in the shaded control, however, exhibited significantly more morphological stress symptoms, with reduced shoot growth and lower below ground biomass. These data suggest that for seagrass exposed to periods of acute light stress, energetic costs associated with photo-acclimation to more variable light regimes can be offset if the plant can meet its daily light requirements during periods of high light. Management of seagrass beds should incorporate regular light monitoring and move towards an adaptive feedback-based approach to ensure the long-term viability of these vulnerable ecosystems.

Daytime exposure to bright light, as compared to dim light, decreases sleepiness and improves psychomotor vigilance performance.

PubMed

Phipps-Nelson, Jo; Redman, Jennifer R; Dijk, Derk-Jan; Rajaratnam, Shantha M W

2003-09-01

This study examined the effects of bright light exposure, as compared to dim light, on daytime subjective sleepiness, incidences of slow eye movements (SEMs), and psychomotor vigilance task (PVT) performance following 2 nights of sleep restriction. The study had a mixed factorial design with 2 independent variables: light condition (bright light, 1,000 lux; dim light, < 5 lux) and time of day. The dependent variables were subjective sleepiness, PVT performance, incidences of SEMs, and salivary melatonin levels. Sleep research laboratory at Monash University. Sixteen healthy adults (10 women and 6 men) aged 18 to 35 years (mean age 25 years, 3 months). Following 2 nights of sleep restriction (5 hours each night), participants were exposed to modified constant routine conditions. Eight participants were exposed to bright light from noon until 5:00 pm. Outside the bright light exposure period (9:00 am to noon, 5:00 pm to 9:00 pm) light levels were maintained at less than 5 lux. A second group of 8 participants served as controls for the bright light exposure and were exposed to dim light throughout the entire protocol. Bright light exposure reduced subjective sleepiness, decreased SEMs, and improved PVT performance compared to dim light. Bright lights had no effect on salivary melatonin. A significant positive correlation between PVT reaction times and subjective sleepiness was observed for both groups. Changes in SEMs did not correlate significantly with either subjective sleepiness or PVT performance. Daytime bright light exposure can reduce the impact of sleep loss on sleepiness levels and performance, as compared to dim light. These effects appear to be mediated by mechanisms that are separate from melatonin suppression. The results may assist in the development of treatments for daytime sleepiness.

Assessment of the Effects of Light Availability on Growth and Competition Between Strains of Planktothrix agardhii and Microcystis aeruginosa.

PubMed

Torres, Camila de Araujo; Lürling, Miquel; Marinho, Marcelo Manzi

2016-05-01

In this study, we tested the hypothesis that Planktothrix agardhii strains isolated from a tropical water body were better competitors for light than Microcystis aeruginosa strains. These cyanobacteria are common in eutrophic systems, where light is one of the main drivers of phytoplankton, and Planktothrix is considered more shade-adapted and Microcystis more high-light tolerant. First, the effect of light intensities on growth was studied in batch cultures. Next, the minimum requirement of light (I*) and the effect of light limitation on the outcome of competition was investigated in chemostats. All strains showed similar growth at 10 μmol photons m(-2) s(-1), demonstrating the ability of the two species to grow in low light. The optimum light intensity was lower for P. agardhii, but at the highest light intensity, Microcystis strains reached higher biovolume, confirming that P. agardhii has higher sensitivity to high light. Nonetheless, P. agardhii grew in light intensities considered high (500 μmol photons m(-2) s(-1)) for this species. M. aeruginosa showed a higher carrying capacity in light-limited condition, but I* was similar between all the strains. Under light competition, Microcystis strains displaced P. agardhii and dominated. In two cases, there was competitive exclusion and in the other two P. agardhii managed to remain in the system with a low biovolume (≈15%). Our findings not only show that strains of P. agardhii can grow under higher light intensities than generally assumed but also that strains of M. aeruginosa are better competitors for light than supposed. These results help to understand the co-occurrence of these species in tropical environments and the dominance of M. aeruginosa even in low-light conditions.

Blue light-induced immunosuppression in Bactrocera dorsalis adults, as a carryover effect of larval exposure.

PubMed

Tariq, K; Noor, M; Hori, M; Ali, A; Hussain, A; Peng, W; Chang, C-J; Zhang, H

2017-12-01

Detrimental effects of ultraviolet (UV) light on living organisms are well understood, little is known about the effects of blue light irradiation. Although a recent study revealed that blue light caused more harmful effects on insects than UV light and blue light irradiation killed insect pests of various orders including Diptera, the effects of blue light on physiology of insects are still largely unknown. Here we studied the effects of blue light irradiation on cuticular melanin in larval and the immune response in adult stage of Bactrocera dorsalis. We also evaluated the effects of blue light exposure in larval stage on various age and mass at metamorphosis and the mediatory role of cuticular melanin in carryover effects of larval stressors across metamorphosis. We found that larvae exposed to blue light decreased melanin contents in their exoskeleton with smaller mass and delayed metamorphosis than insects reared without blue light exposure. Across metamorphosis, lower melanotic encapsulation response and higher susceptibility to Beauveria bassiana was detected in adults that had been exposed to blue light at their larval stage, thereby constituting the first evidence that blue light impaired adult immune function in B. dorsalis as a carryover effect of larval exposure.

Visualization and Analysis of Light Pollution: a Case Study in Hong Kong

NASA Astrophysics Data System (ADS)

Wu, B.; Wong, H.

2012-07-01

The effects of light pollution problems in metropolitan areas are investigated in this study. Areas of Hong Kong are used as the source of three typical study cases. One case represents the regional scale, a second represents the district scale, and a third represents the street scale. Two light pollution parameters, Night Sky Brightness (NSB) and Street Light Level (SLL), are the focus of the analyses. Light pollution visualization approaches in relation to the different scales include various light pollution maps. They provide straightforward presentations of the light pollution situations in the study areas. The relationship between light pollution and several social-economic factors such as land use, household income, and types of outdoor lighting in the scale areas given, are examined. Results show that: (1) Land use may be one factor affecting light pollution in the regional scale; (2) A relatively strong correlation exists between light pollution and household income in the district scale; (3) The heaviest light pollution in the street scale is created by spotlights and also the different types of lighting from shops. The impact of the latter is in relation to the shop profile and size.

The thinker: opposing directionality of lighting bias within sculptural artwork

PubMed Central

Sedgewick, Jennifer R.; Weiers, Bradley; Stewart, Aaron; Elias, Lorin J.

2015-01-01

Individuals tend to perceive the direction of light to come from above and slightly from the left; it has been speculated that this phenomenon is also producing similar lighting preferences within 2-dimensional artworks (e.g., paintings, advertisements). The purpose of the present study was to address if lighting bias was present in the 3-dimensional medium of sculpture by implementing a virtual art gallery lighting paradigm. Thirty-nine participants completed a computer task that consisted of 48 galleries each containing one sculpture (24 original sculptures, 24 mirror-reversed) which was surrounded by eight lights (above/below, left/right, front/back). Participants would select one light source to illuminate the sculpture in a manner they perceived to be the most aesthetically pleasing. The results indicated a significant preference for lights positioned from above and from the right, a finding that is contradictory to previous lighting bias research examining artworks. An interpretation for the rightward bias applies the perceptual concept of subjective lighting equality. Objects illuminated from the left typically appear brighter in comparison to right-side lighting; in sculpture, however, increased luminosity can reduce the sculptural detail, and may have been compensated via right-side lighting choices within the lighting task. PMID:25999840

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, Lynn; Arquit Niederberger, Anne

Abstract— Lighting systems have the ability to transform the economic and educational infrastructure of disadvantaged communities, and eradicating “light poverty” has become one of the primary goals of the International Year of Light 2015. Solid-state lighting (SSL) technology, based on light-emitting diode (LED) light sources, has emerged as the next generation of lighting technology, with a current global market penetration of roughly 5%. This paper will report on recent research on understanding SSL lighting system reliability (failure modes, environmental stressors, electrical power quality); discuss the implications of SSL technology reliability for providing lighting services; and suggest practical approaches to ensuremore » SSL reliability to benefit humanity. Among the key findings from this work is that LED sources can be extremely reliable, withstanding a broad range of environmental stresses without failure. Nonetheless, SSL lighting systems can have a negative impact on electrical power reliability, as well as on the affordability of lighting services, without attention to the quality of the accompanying power infrastructure. It is therefore critical to ensure that the performance of the power supply electronics used in lighting systems is matched to the quality of the power source, when evaluating energy efficient lighting choices.« less

Solid-State Laser Source of Tunable Narrow-Bandwidth Ultraviolet Radiation

NASA Technical Reports Server (NTRS)

Goldberg, Lew; Kliner, Dahv A.; Koplow, Jeffrey P.

1998-01-01

A solid-state laser source of tunable and narrow-bandwidth UV light is disclosed. The system relies on light from a diode laser that preferably generates light at infrared frequencies. The light from the seed diode laser is pulse amplified in a light amplifier, and converted into the ultraviolet by frequency tripling, quadrupling, or quintupling the infrared light. The narrow bandwidth, or relatively pure light, of the seed laser is preserved, and the pulse amplifier generates high peak light powers to increase the efficiency of the nonlinear crystals in the frequency conversion stage. Higher output powers may be obtained by adding a fiber amplifier to power amplify the pulsed laser light prior to conversion.

Protection of Hawaii's Observatories from Light Pollution

NASA Astrophysics Data System (ADS)

Wainscoat, Richard J.

2018-01-01

Maunakea Observatory, located on the island of Hawaii, is among the world darkest sites for astronomy. Strong efforts to preserve the dark night sky over the last forty years have proven successful. Artificial light presently adds only approximately 2% to the natural night sky brightness. The techniques being used to protect Maunakea from light pollution will be described, along with the challenges that are now being faced.Haleakala Observatory, located on the island of Maui, is also an excellent observing site, and is among the best sites in the United States. Lighting restrictions in Maui County are much weaker, and consequently, the night sky above Haleakala is less well protected. Haleakala is closer to Honolulu and the island of Oahu (population approximately 1 million), and the glow from Oahu makes the northwestern sky brighter.Much of the lighting across most of the United States, including Hawaii, is presently being converted to LED lighting. This provides an opportunity to replace existing poorly shielded lights with properly shielded LED fixtures, but careful spectral management is essential. It is critically important to only use LED lighting that is deficient in blue and green light. LED lighting also is easy to dim. Dimming of lights later at night, when there is no need for brighter lighting, is an important tool for reducing light pollution.Techniques used to protect astronomical observatories from light pollution are similar to the techniques that must be used to protect animals that are affected by light at night, such as endangered birds and turtles. These same techniques are compatible with recent human health related lighting recommendations from the American Medical Association.

Response of bats to light with different spectra: light-shy and agile bat presence is affected by white and green, but not red light

PubMed Central

van Grunsven, Roy H. A.; Ramakers, Jip J. C.; Ferguson, Kim B.; Raap, Thomas; Donners, Maurice; Veenendaal, Elmar M.; Visser, Marcel E.

2017-01-01

Artificial light at night has shown a remarkable increase over the past decades. Effects are reported for many species groups, and include changes in presence, behaviour, physiology and life-history traits. Among these, bats are strongly affected, and how bat species react to light is likely to vary with light colour. Different spectra may therefore be applied to reduce negative impacts. We used a unique set-up of eight field sites to study the response of bats to three different experimental light spectra in an otherwise dark and undisturbed natural habitat. We measured activity of three bat species groups around transects with light posts emitting white, green and red light with an intensity commonly used to illuminate countryside roads. The results reveal a strong and spectrum-dependent response for the slow-flying Myotis and Plecotus and more agile Pipistrellus species, but not for Nyctalus and Eptesicus species. Plecotus and Myotis species avoided white and green light, but were equally abundant in red light and darkness. The agile, opportunistically feeding Pipistrellus species were significantly more abundant around white and green light, most likely because of accumulation of insects, but equally abundant in red illuminated transects compared to dark control. Forest-dwelling Myotis and Plecotus species and more synanthropic Pipistrellus species are thus least disturbed by red light. Hence, in order to limit the negative impact of light at night on bats, white and green light should be avoided in or close to natural habitat, but red lights may be used if illumination is needed. PMID:28566484

Sensitivity of the human circadian pacemaker to nocturnal light: melatonin phase resetting and suppression

NASA Technical Reports Server (NTRS)

Zeitzer, J. M.; Dijk, D. J.; Kronauer, R.; Brown, E.; Czeisler, C.

2000-01-01

Ocular exposure to early morning room light can significantly advance the timing of the human circadian pacemaker. The resetting response to such light has a non-linear relationship to illuminance. The dose-response relationship of the human circadian pacemaker to late evening light of dim to moderate intensity has not been well established. Twenty-three healthy young male and female volunteers took part in a 9 day protocol in which a single experimental light exposure6.5 h in duration was given in the early biological night. The effects of the light exposure on the endogenous circadian phase of the melatonin rhythm and the acute effects of the light exposure on plasma melatonin concentration were calculated. We demonstrate that humans are highly responsive to the phase-delaying effects of light during the early biological night and that both the phase resetting response to light and the acute suppressive effects of light on plasma melatonin follow a logistic dose-response curve, as do many circadian responses to light in mammals. Contrary to expectations, we found that half of the maximal phase-delaying response achieved in response to a single episode of evening bright light ( approximately 9000 lux (lx)) can be obtained with just over 1 % of this light (dim room light of approximately 100 lx). The same held true for the acute suppressive effects of light on plasma melatonin concentrations. This indicates that even small changes in ordinary light exposure during the late evening hours can significantly affect both plasma melatonin concentrations and the entrained phase of the human circadian pacemaker.

Acute Effects of Morning Light on Plasma Glucose and Triglycerides in Healthy Men and Men with Type 2 Diabetes

PubMed Central

Versteeg, Ruth I.; Stenvers, Dirk J.; Visintainer, Dana; Linnenbank, Andre; Tanck, Michael W.; Zwanenburg, Gooitzen; Smilde, Age K.; Fliers, Eric; Kalsbeek, Andries; Serlie, Mireille J.; la Fleur, Susanne E.; Bisschop, Peter H.

2017-01-01

Ambient light intensity is signaled directly to hypothalamic areas that regulate energy metabolism. Observational studies have shown associations between ambient light intensity and plasma glucose and lipid levels, but human data on the acute metabolic effects of light are scarce. Since light is the main signal indicating the onset of the diurnal phase of physical activity and food intake in humans, we hypothesized that bright light would affect glucose and lipid metabolism. Therefore, we determined the acute effects of bright light on plasma glucose and lipid concentrations in 2 randomized crossover trials: (1) in 8 healthy lean men and (2) in 8 obese men with type 2 diabetes. From 0730 h, subjects were exposed to either bright light (4000 lux) or dim light (10 lux) for 5 h. After 1 h of light exposure, subjects consumed a 600-kcal mixed meal. Primary endpoints were fasting and postprandial plasma glucose levels. In healthy men, bright light did not affect fasting or postprandial plasma glucose levels. However, bright light increased fasting and postprandial plasma triglycerides. In men with type 2 diabetes, bright light increased fasting and postprandial glucose levels. In men with type 2 diabetes, bright light did not affect fasting triglyceride levels but increased postprandial triglyceride levels. We show that ambient light intensity acutely affects human plasma glucose and triglyceride levels. Our findings warrant further research into the consequences of the metabolic effects of light for the diagnosis and prevention of hyperglycemia and dyslipidemia. PMID:28470119

Uv-Light Stabilization Additive Package For Solar Cell Module And Laminated Glass Applications

DOEpatents

Hanoka, Jack I.; Klemchuk, Peter P.

2002-03-05

An ultraviolet light stabilization additive package is used in an encapsulant material that may be used in solar cell modules, laminated glass and a variety of other applications. The ultraviolet light stabilization additive package comprises a first hindered amine light stabilizer and a second hindered amine light stabilizer. The first hindered amine light stabilizer provides thermal oxidative stabilization, and the second hindered amine light stabilizer providing photo-oxidative stabilization.

Polarization-balanced beamsplitter

DOEpatents

Decker, D.E.

1998-02-17

A beamsplitter assembly is disclosed that includes several beamsplitter cubes arranged to define a plurality of polarization-balanced light paths. Each polarization-balanced light path contains one or more balanced pairs of light paths, where each balanced pair of light paths includes either two transmission light paths with orthogonal polarization effects or two reflection light paths with orthogonal polarization effects. The orthogonal pairing of said transmission and reflection light paths cancels polarization effects otherwise caused by beamsplitting. 10 figs.

Combatant Eye Protection: An Introduction to the Blue Light Hazard

DTIC Science & Technology

2015-12-01

visible solar radiation (i.e., blue light ), as well as from light - emitting diode (LED)-generated radiant energy remains a questionable factor under...Garcia, M., Picaud, S., Attia D. 2011. Light - emitting diodes (LED) for domestic lighting : Any risks for the eye?. Progress in retinal and eye research...C., Sliney, D. H., Rollag, M., D., Hanifin, J. P., and Brainard, G. C. 2011. Blue light from light - emitting diodes elicits a dose-dependent

Flexible, liquid core light guide with focusing and light shaping attachments

DOEpatents

Wojcik, Randolph Frank; Majewski, Stanislaw; Zorn, Carl John; Kross, Brian

1999-01-01

A liquid light guide system for ultraviolet light is disclosed that has a light shaping arrangement for the emitted light, a stable liquid core and sheath and reliable and effective end closures. The end closures include a metal crimping arrangement that utilizes two layers of deformable materials to prevent cracking of endplugs.

Investigative Photography, 16-1. Military Curriculum Materials for Vocational and Technical Education.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus. National Center for Research in Vocational Education.

This military-developed text consists of nine lessons dealing with investigative photography. Covered in the individual lessons are the following topics: light (light as the basis of photography, the behavior of light, the composition of white light, light transmission, reflection and absorption, illumination, and pinholes and light); camera…

Light intensity and quality from sole-source light-emitting diodes impact growth, morphology, and nutrient content of Brassica microgreens

USDA-ARS?s Scientific Manuscript database

Multi-layer vertical production systems using sole-source (SS) lighting can be used for microgreen production; however, traditional SS lighting can consume large amounts of electrical energy. Light-emitting diodes (LEDs) offer many advantages over conventional light sources including: high photoelec...

14 CFR 151.87 - Lighting and electrical work: Standards.

Code of Federal Regulations, 2014 CFR

2014-01-01

... participate in the costs of runway lighting is eligible for the installing of an airport beacon, lighted wind... percent U.S. participation in the costs of high intensity runway edge lighting (or the allowable.... share of the cost of runway edge lighting is 50 percent of the cost of the lighting installed but not...

14 CFR 151.87 - Lighting and electrical work: Standards.

Code of Federal Regulations, 2012 CFR

2012-01-01

... participate in the costs of runway lighting is eligible for the installing of an airport beacon, lighted wind... percent U.S. participation in the costs of high intensity runway edge lighting (or the allowable.... share of the cost of runway edge lighting is 50 percent of the cost of the lighting installed but not...

14 CFR 151.87 - Lighting and electrical work: Standards.

Code of Federal Regulations, 2013 CFR

2013-01-01

... participate in the costs of runway lighting is eligible for the installing of an airport beacon, lighted wind... percent U.S. participation in the costs of high intensity runway edge lighting (or the allowable.... share of the cost of runway edge lighting is 50 percent of the cost of the lighting installed but not...

Redwood seedling responses to light patterns and intensities

Treesearch

Ronald W. Boldenow; Joe R. McBride

2017-01-01

Coast redwood (Sequoia sempervirens (D. Don) Endl.) seedlings were grown from seed in controlled environments with 16 hour photoperiods using three light patterns that mimicked full shade (constant light level), intermittent high light such as long duration sun flecks (low light with 15 minutes of intense light every 2 hours), and large...

Shining a Light on Electronics

ERIC Educational Resources Information Center

Statler, James D.

2009-01-01

While they produced a limited amount of light when first introduced, light-emitting diode (LED) lights offered the benefit of rarely burning out. As a result, they were initially used primarily as indicator lights. Advances in the technology have made available LEDs that produce far brighter light, and one application that has come to market is…

14 CFR 121.323 - Instruments and equipment for operations at night.

Code of Federal Regulations, 2014 CFR

2014-01-01

... required by §§ 121.305 through 121.321 and 121.803: (a) Position lights. (b) An anti-collision light. (c) Two landing lights, except that only one landing light is required for nontransport category airplanes type certificated after December 31, 1964. (d) Instrument lights providing enough light to make each...

14 CFR 121.323 - Instruments and equipment for operations at night.

Code of Federal Regulations, 2012 CFR

2012-01-01

... required by §§ 121.305 through 121.321 and 121.803: (a) Position lights. (b) An anti-collision light. (c) Two landing lights, except that only one landing light is required for nontransport category airplanes type certificated after December 31, 1964. (d) Instrument lights providing enough light to make each...

14 CFR 121.323 - Instruments and equipment for operations at night.

Code of Federal Regulations, 2010 CFR

2010-01-01

... required by §§ 121.305 through 121.321 and 121.803: (a) Position lights. (b) An anti-collision light. (c) Two landing lights, except that only one landing light is required for nontransport category airplanes type certificated after December 31, 1964. (d) Instrument lights providing enough light to make each...

14 CFR 121.323 - Instruments and equipment for operations at night.

Code of Federal Regulations, 2013 CFR

2013-01-01

... required by §§ 121.305 through 121.321 and 121.803: (a) Position lights. (b) An anti-collision light. (c) Two landing lights, except that only one landing light is required for nontransport category airplanes type certificated after December 31, 1964. (d) Instrument lights providing enough light to make each...

14 CFR 121.323 - Instruments and equipment for operations at night.

Code of Federal Regulations, 2011 CFR

2011-01-01

... required by §§ 121.305 through 121.321 and 121.803: (a) Position lights. (b) An anti-collision light. (c) Two landing lights, except that only one landing light is required for nontransport category airplanes type certificated after December 31, 1964. (d) Instrument lights providing enough light to make each...

33 CFR 118.85 - Lights on vertical lift bridges.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

33 CFR 118.85 - Lights on vertical lift bridges.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

14 CFR 151.87 - Lighting and electrical work: Standards.

Code of Federal Regulations, 2011 CFR

2011-01-01

... participate in the costs of runway lighting is eligible for the installing of an airport beacon, lighted wind... percent U.S. participation in the costs of high intensity runway edge lighting (or the allowable.... share of the cost of runway edge lighting is 50 percent of the cost of the lighting installed but not...

14 CFR 151.87 - Lighting and electrical work: Standards.

Code of Federal Regulations, 2010 CFR

2010-01-01

... participate in the costs of runway lighting is eligible for the installing of an airport beacon, lighted wind... percent U.S. participation in the costs of high intensity runway edge lighting (or the allowable.... share of the cost of runway edge lighting is 50 percent of the cost of the lighting installed but not...

40 CFR 86.1840-01 - Special test procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light-Duty Trucks... those set forth in this part, for any light-duty vehicle, light-duty truck, or complete heavy-duty... special test procedures but the Administrator determines that a light-duty vehicle, light-duty truck, or...

33 CFR 67.30-5 - Obstruction lights.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Obstruction lights. 67.30-5... Obstruction lights. (a) The obstruction lights shall be white or red lights as prescribed in Subpart 67.05 of... nautical mile 90 percent of the nights of the year. The lights shall be displayed at such height, above...

46 CFR 111.75-17 - Navigation lights.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Navigation lights. 111.75-17 Section 111.75-17 Shipping... REQUIREMENTS Lighting Circuits and Protection § 111.75-17 Navigation lights. Each navigation light system must...-5(a) of this chapter, each navigation light panel must be supplied by a feeder from the emergency...

14 CFR 27.1399 - Riding light.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Riding light. 27.1399 Section 27.1399... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1399 Riding light. (a) Each riding light required for water operation must be installed so that it can— (1) Show a white light for at least two...

14 CFR 25.1399 - Riding light.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Riding light. 25.1399 Section 25.1399... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1399 Riding light. (a) Each riding (anchor) light required for a seaplane or amphibian must be installed so that it can— (1) Show a white light for...

14 CFR 29.1399 - Riding light.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Riding light. 29.1399 Section 29.1399... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1399 Riding light. (a) Each riding light required for water operation must be installed so that it can— (1) Show a white light for at least two...

33 CFR 67.20-5 - Obstruction lights.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Obstruction lights. 67.20-5... Obstruction lights. The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this part. The lights shall be of sufficient candlepower as to be visible at a distance of at least five nautical...

46 CFR 111.75-17 - Navigation lights.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Navigation lights. 111.75-17 Section 111.75-17 Shipping... REQUIREMENTS Lighting Circuits and Protection § 111.75-17 Navigation lights. Each navigation light system must...-5(a) of this chapter, each navigation light panel must be supplied by a feeder from the emergency...

33 CFR 67.20-5 - Obstruction lights.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Obstruction lights. 67.20-5... Obstruction lights. The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this part. The lights shall be of sufficient candlepower as to be visible at a distance of at least five nautical...

14 CFR 27.1399 - Riding light.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Riding light. 27.1399 Section 27.1399... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1399 Riding light. (a) Each riding light required for water operation must be installed so that it can— (1) Show a white light for at least two...

14 CFR 25.1399 - Riding light.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Riding light. 25.1399 Section 25.1399... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1399 Riding light. (a) Each riding (anchor) light required for a seaplane or amphibian must be installed so that it can— (1) Show a white light for...

33 CFR 67.20-5 - Obstruction lights.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Obstruction lights. 67.20-5... Obstruction lights. The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this part. The lights shall be of sufficient candlepower as to be visible at a distance of at least five nautical...

14 CFR 29.1399 - Riding light.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Riding light. 29.1399 Section 29.1399... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1399 Riding light. (a) Each riding light required for water operation must be installed so that it can— (1) Show a white light for at least two...

33 CFR 67.25-5 - Obstruction lights.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Obstruction lights. 67.25-5... Obstruction lights. (a) The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this... miles 90 percent of the nights of the year. The lights shall be displayed not less than 20 feet above...

14 CFR 29.1399 - Riding light.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Riding light. 29.1399 Section 29.1399... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1399 Riding light. (a) Each riding light required for water operation must be installed so that it can— (1) Show a white light for at least two...

14 CFR 27.1399 - Riding light.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Riding light. 27.1399 Section 27.1399... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1399 Riding light. (a) Each riding light required for water operation must be installed so that it can— (1) Show a white light for at least two...

33 CFR 67.20-5 - Obstruction lights.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Obstruction lights. 67.20-5... Obstruction lights. The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this part. The lights shall be of sufficient candlepower as to be visible at a distance of at least five nautical...

14 CFR 27.1399 - Riding light.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Riding light. 27.1399 Section 27.1399... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1399 Riding light. (a) Each riding light required for water operation must be installed so that it can— (1) Show a white light for at least two...

33 CFR 67.30-5 - Obstruction lights.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Obstruction lights. 67.30-5... Obstruction lights. (a) The obstruction lights shall be white or red lights as prescribed in Subpart 67.05 of... nautical mile 90 percent of the nights of the year. The lights shall be displayed at such height, above...

33 CFR 67.30-5 - Obstruction lights.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Obstruction lights. 67.30-5... Obstruction lights. (a) The obstruction lights shall be white or red lights as prescribed in Subpart 67.05 of... nautical mile 90 percent of the nights of the year. The lights shall be displayed at such height, above...

33 CFR 67.25-5 - Obstruction lights.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Obstruction lights. 67.25-5... Obstruction lights. (a) The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this... miles 90 percent of the nights of the year. The lights shall be displayed not less than 20 feet above...

33 CFR 67.30-5 - Obstruction lights.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Obstruction lights. 67.30-5... Obstruction lights. (a) The obstruction lights shall be white or red lights as prescribed in Subpart 67.05 of... nautical mile 90 percent of the nights of the year. The lights shall be displayed at such height, above...

46 CFR 111.75-17 - Navigation lights.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Navigation lights. 111.75-17 Section 111.75-17 Shipping... REQUIREMENTS Lighting Circuits and Protection § 111.75-17 Navigation lights. Each navigation light system must...-5(a) of this chapter, each navigation light panel must be supplied by a feeder from the emergency...

46 CFR 111.75-17 - Navigation lights.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Navigation lights. 111.75-17 Section 111.75-17 Shipping... REQUIREMENTS Lighting Circuits and Protection § 111.75-17 Navigation lights. Each navigation light system must...-5(a) of this chapter, each navigation light panel must be supplied by a feeder from the emergency...

14 CFR 25.1399 - Riding light.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Riding light. 25.1399 Section 25.1399... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1399 Riding light. (a) Each riding (anchor) light required for a seaplane or amphibian must be installed so that it can— (1) Show a white light for...

33 CFR 67.30-5 - Obstruction lights.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Obstruction lights. 67.30-5... Obstruction lights. (a) The obstruction lights shall be white or red lights as prescribed in Subpart 67.05 of... nautical mile 90 percent of the nights of the year. The lights shall be displayed at such height, above...

14 CFR 25.1399 - Riding light.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Riding light. 25.1399 Section 25.1399... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1399 Riding light. (a) Each riding (anchor) light required for a seaplane or amphibian must be installed so that it can— (1) Show a white light for...

33 CFR 67.25-5 - Obstruction lights.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Obstruction lights. 67.25-5... Obstruction lights. (a) The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this... miles 90 percent of the nights of the year. The lights shall be displayed not less than 20 feet above...

14 CFR 29.1399 - Riding light.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Riding light. 29.1399 Section 29.1399... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1399 Riding light. (a) Each riding light required for water operation must be installed so that it can— (1) Show a white light for at least two...

14 CFR 29.1399 - Riding light.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Riding light. 29.1399 Section 29.1399... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1399 Riding light. (a) Each riding light required for water operation must be installed so that it can— (1) Show a white light for at least two...

33 CFR 67.20-5 - Obstruction lights.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Obstruction lights. 67.20-5... Obstruction lights. The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this part. The lights shall be of sufficient candlepower as to be visible at a distance of at least five nautical...

46 CFR 111.75-17 - Navigation lights.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Navigation lights. 111.75-17 Section 111.75-17 Shipping... REQUIREMENTS Lighting Circuits and Protection § 111.75-17 Navigation lights. Each navigation light system must...-5(a) of this chapter, each navigation light panel must be supplied by a feeder from the emergency...

14 CFR 27.1399 - Riding light.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Riding light. 27.1399 Section 27.1399... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1399 Riding light. (a) Each riding light required for water operation must be installed so that it can— (1) Show a white light for at least two...

14 CFR 25.1399 - Riding light.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Riding light. 25.1399 Section 25.1399... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1399 Riding light. (a) Each riding (anchor) light required for a seaplane or amphibian must be installed so that it can— (1) Show a white light for...

Sequential light programs shape kale (Brassica napus) sprout appearance and alter metabolic and nutrient content

PubMed Central

Carvalho, Sofia D; Folta, Kevin M

2014-01-01

Different light wavelengths have specific effects on plant growth and development. Narrow-bandwidth light-emitting diode (LED) lighting may be used to directionally manipulate size, color and metabolites in high-value fruits and vegetables. In this report, Red Russian kale (Brassica napus) seedlings were grown under specific light conditions and analyzed for photomorphogenic responses, pigment accumulation and nutraceutical content. The results showed that this genotype responds predictably to darkness, blue and red light, with suppression of hypocotyl elongation, development of pigments and changes in specific metabolites. However, these seedlings were relatively hypersensitive to far-red light, leading to uncharacteristically short hypocotyls and high pigment accumulation, even after growth under very low fluence rates (<1 μmol m−2 s−1). General antioxidant levels and aliphatic glucosinolates are elevated by far-red light treatments. Sequential treatments of darkness, blue light, red light and far-red light were applied throughout sprout development to alter final product quality. These results indicate that sequential treatment with narrow-bandwidth light may be used to affect key economically important traits in high-value crops. PMID:26504531

Relevance of Light Spectra to Growth of the Rearing Tiger Puffer Takifugu rubripes

PubMed Central

Kim, Byeong-Hoon; Hur, Sung-Pyo; Hur, Sang-Woo; Lee, Chi-Hoon; Lee, Young-Don

2016-01-01

In fish, light (photoperiod, intensity and spectra) is main regulator in many physiological actions includinggrowth. We investigate the effect of light spectra on the somatic growth and growth-related gene expression in the rearing tiger puffer. Fish was reared under different light spectra (blue, green and red) for 8 weeks. Fish body weight and total length were promoted when reared under green light condition than red light condition. Expression of somatostatins (ss1 and ss2) in brain were showed higher expression under red light condition than green light condition. The ss3 mRNA was observed only higher expression in blue light condition. Expression of growth hormone (gh) in pituitary was detected no different levels between experimental groups. However, the fish of green light condition group was showed more high weight gain and feed efficiency than other light condition groups. Our present results suggest that somatic growth of tiger puffer is induced under green light condition because of inhibiting ss mRNA expression in brain by effect of green wavelength. PMID:27294208

Effective light absorption and its enhancement factor for silicon nanowire-based solar cell.

PubMed

Duan, Zhiqiang; Li, Meicheng; Mwenya, Trevor; Fu, Pengfei; Li, Yingfeng; Song, Dandan

2016-01-01

Although nanowire (NW) antireflection coating can enhance light trapping capability, which is generally used in crystal silicon (CS) based solar cells, whether it can improve light absorption in the CS body depends on the NW geometrical shape and their geometrical parameters. In order to conveniently compare with the bare silicon, two enhancement factors E(T) and E(A) are defined and introduced to quantitatively evaluate the efficient light trapping capability of NW antireflective layer and the effective light absorption capability of CS body. Five different shapes (cylindrical, truncated conical, convex conical, conical, and concave conical) of silicon NW arrays arranged in a square are studied, and the theoretical results indicate that excellent light trapping does not mean more light can be absorbed in the CS body. The convex conical NW has the best light trapping, but the concave conical NW has the best effective light absorption. Furthermore, if the cross section of silicon NW is changed into a square, both light trapping and effective light absorption are enhanced, and the Eiffel Tower shaped NW arrays have optimal effective light absorption.

Experimentally comparing the attractiveness of domestic lights to insects: Do LEDs attract fewer insects than conventional light types?

PubMed

Wakefield, Andrew; Broyles, Moth; Stone, Emma L; Jones, Gareth; Harris, Stephen

2016-11-01

LED lighting is predicted to constitute 70% of the outdoor and residential lighting markets by 2020. While the use of LEDs promotes energy and cost savings relative to traditional lighting technologies, little is known about the effects these broad-spectrum "white" lights will have on wildlife, human health, animal welfare, and disease transmission. We conducted field experiments to compare the relative attractiveness of four commercially available "domestic" lights, one traditional (tungsten filament) and three modern (compact fluorescent, "cool-white" LED and "warm-white" LED), to aerial insects, particularly Diptera. We found that LEDs attracted significantly fewer insects than other light sources, but found no significant difference in attraction between the "cool-" and "warm-white" LEDs. Fewer flies were attracted to LEDs than alternate light sources, including fewer Culicoides midges (Diptera: Ceratopogonidae). Use of LEDs has the potential to mitigate disturbances to wildlife and occurrences of insect-borne diseases relative to competing lighting technologies. However, we discuss the risks associated with broad-spectrum lighting and net increases in lighting resulting from reduced costs of LED technology.

Method and apparatus for reading lased bar codes on shiny-finished fuel rod cladding tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldenfield, M.P.; Lambert, D.V.

1990-10-02

This patent describes, in a nuclear fuel rod identification system, a method of reading a bar code etched directly on a surface of a nuclear fuel rod. It comprises: defining a pair of light diffuser surfaces adjacent one another but in oppositely inclined relation to a beam of light emitted from a light reader; positioning a fuel rod, having a cylindrical surface portion with a bar code etched directly thereon, relative to the light diffuser surfaces such that the surfaces are disposed adjacent to and in oppositely inclined relation along opposite sides of the fuel rod surface portion and themore » fuel rod surface portion is aligned with the beam of light emitted from the light reader; directing the beam of light on the bar code on fuel rod cylindrical surface portion such that the light is reflected therefrom onto one of the light diffuser surfaces; and receiving and reading the reflected light from the bar code via the one of the light diffuser surfaces to the light reader.« less

Efficient and bright organic light-emitting diodes on single-layer graphene electrodes

NASA Astrophysics Data System (ADS)

Li, Ning; Oida, Satoshi; Tulevski, George S.; Han, Shu-Jen; Hannon, James B.; Sadana, Devendra K.; Chen, Tze-Chiang

2013-08-01

Organic light-emitting diodes are emerging as leading technologies for both high quality display and lighting. However, the transparent conductive electrode used in the current organic light-emitting diode technologies increases the overall cost and has limited bendability for future flexible applications. Here we use single-layer graphene as an alternative flexible transparent conductor, yielding white organic light-emitting diodes with brightness and efficiency sufficient for general lighting. The performance improvement is attributed to the device structure, which allows direct hole injection from the single-layer graphene anode into the light-emitting layers, reducing carrier trapping induced efficiency roll-off. By employing a light out-coupling structure, phosphorescent green organic light-emitting diodes exhibit external quantum efficiency >60%, while phosphorescent white organic light-emitting diodes exhibit external quantum efficiency >45% at 10,000 cd m-2 with colour rendering index of 85. The power efficiency of white organic light-emitting diodes reaches 80 lm W-1 at 3,000 cd m-2, comparable to the most efficient lighting technologies.

A comparison of the light-reduction capacity of commonly used incubator covers.

PubMed

Lee, Yi-Hui; Malakooti, Nima; Lotas, Marilyn

2005-01-01

The use of incubator covers to enhance preterm infants' rest and recovery is common in the NICU. However, the kinds of covers used vary extensively among and within nurseries. Few data exist on the effectiveness of different types of covers in reducing light levels to the infant. This study compared several types of commonly used incubator covers as to efficacy of light reduction. A descriptive, comparative design was used in this study. Twenty-three incubator covers were tested, including professional, receiving blanket, hand-crocheted, three-layer quilt, and flannel. The percentage of light level reduction of different incubator covers under various ambient light level settings. The amount of light reduction provided by incubator covers varies depending on type of fabric as well as percentage of incubator surface shielded by the cover. Dark-colored covers provided greater light reduction than bright/light-colored covers when covers identical in fabric type were compared. The light-reduction efficiency of the covers varied depending on the level of ambient light. Covers provided less light reduction in higher ambient light levels.

77 FR 75189 - Certain Light-Emitting Diodes and Products Containing Same; Commission Determination Not To...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-19

... Corporate Center USA, Hella, Inc., Automotive Lighting Reutlingen GmbH, Automotive Lighting LLC, Tecnologia..., Inc., Automotive Lighting Reutlingen GmbH, Automotive Lighting, LLC, and [[Page 75190

1. Light tower/keeper's house and abandoned light tower, view northwest, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Light tower/keeper's house and abandoned light tower, view northwest, south southeast and east northeast sides - Matinicus Rock Light Station, Matinicus Island, on Matinicus Rock, Matinicus, Knox County, ME

2. Abandoned light tower and keeper's house/light tower, view southeast, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. Abandoned light tower and keeper's house/light tower, view southeast, north northwest and west southwest sides - Matinicus Rock Light Station, Matinicus Island, on Matinicus Rock, Matinicus, Knox County, ME

Effects of blue light on the circadian system and eye physiology.

PubMed

Tosini, Gianluca; Ferguson, Ian; Tsubota, Kazuo

2016-01-01

Light-emitting diodes (LEDs) have been used to provide illumination in industrial and commercial environments. LEDs are also used in TVs, computers, smart phones, and tablets. Although the light emitted by most LEDs appears white, LEDs have peak emission in the blue light range (400-490 nm). The accumulating experimental evidence has indicated that exposure to blue light can affect many physiologic functions, and it can be used to treat circadian and sleep dysfunctions. However, blue light can also induce photoreceptor damage. Thus, it is important to consider the spectral output of LED-based light sources to minimize the danger that may be associated with blue light exposure. In this review, we summarize the current knowledge of the effects of blue light on the regulation of physiologic functions and the possible effects of blue light exposure on ocular health.

Spatial and Angular Resolution Enhancement of Light Fields Using Convolutional Neural Networks

NASA Astrophysics Data System (ADS)

Gul, M. Shahzeb Khan; Gunturk, Bahadir K.

2018-05-01

Light field imaging extends the traditional photography by capturing both spatial and angular distribution of light, which enables new capabilities, including post-capture refocusing, post-capture aperture control, and depth estimation from a single shot. Micro-lens array (MLA) based light field cameras offer a cost-effective approach to capture light field. A major drawback of MLA based light field cameras is low spatial resolution, which is due to the fact that a single image sensor is shared to capture both spatial and angular information. In this paper, we present a learning based light field enhancement approach. Both spatial and angular resolution of captured light field is enhanced using convolutional neural networks. The proposed method is tested with real light field data captured with a Lytro light field camera, clearly demonstrating spatial and angular resolution improvement.

Spatial and Angular Resolution Enhancement of Light Fields Using Convolutional Neural Networks.

PubMed

Gul, M Shahzeb Khan; Gunturk, Bahadir K

2018-05-01

Light field imaging extends the traditional photography by capturing both spatial and angular distribution of light, which enables new capabilities, including post-capture refocusing, post-capture aperture control, and depth estimation from a single shot. Micro-lens array (MLA) based light field cameras offer a cost-effective approach to capture light field. A major drawback of MLA based light field cameras is low spatial resolution, which is due to the fact that a single image sensor is shared to capture both spatial and angular information. In this paper, we present a learning based light field enhancement approach. Both spatial and angular resolution of captured light field is enhanced using convolutional neural networks. The proposed method is tested with real light field data captured with a Lytro light field camera, clearly demonstrating spatial and angular resolution improvement.

Water jacket for solid particle solar receiver

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wasyluk, David T.

A solar receiver includes: water jacket panels each having a light-receiving side and a back side with a watertight sealed plenum defined in-between; light apertures passing through the watertight sealed plenums to receive light from the light-receiving sides of the water jacket panels; a heat transfer medium gap defined between the back sides of the water jacket panels and a cylindrical back plate; and light channeling tubes optically coupled with the light apertures and extending into the heat transfer medium gap. In some embodiments ends of the light apertures at the light receiving side of the water jacket panel aremore » welded together to define at least a portion of the light-receiving side. A cylindrical solar receiver may be constructed using a plurality of such water jacket panels arranged with their light-receiving sides facing outward.« less

Blue light- and genetically-reversed gravitropic response in protonemata of the moss Ceratodon purpureus.

PubMed

Lamparter, T; Hughes, J; Hartmann, E

1998-09-01

In darkness, protonemal filaments of Ceratodon purpureus (Brid.) grow negatively gravitropically (upwards). Red light induces a positive phototropic response mediated by the photoreceptor phytochrome. A red light treatment also has an inhibitory effect on the gravitropic response, an effect also mediated by phytochrome. In this study the effects of blue light on phototropism and on gravitropism were analysed. Unilateral blue light resulted in only a weak phototropic response, but markedly randomised growth direction. Blue light given together with a gravitropic stimulus reversed the gravitropism, changing it from negative to positive (filaments grow downward). The effect of blue light was also analysed with the mutant ptr116, which is defective in the biosynthesis of the phytochrome chromophore, and in a newly isolated mutant wwr2, which is positively gravitropic in darkness. Blue light induced the same reversal of gravitropism in ptrll6 as in the wild type, indicating that phytochrome is not involved in this process. In wwr2 the direction of gravitropism was unaltered by the blue light treatment. Light also affects chlorophyll content and the size of plastids, potential statoliths for gravitropism. Red light induced an increase in plastid size and chlorophyll content in the wild type but not in ptr116. Blue light induced a similar change in wild type plastids. It seems as though light-induced alterations of gravitropism are not simply mediated by alterations in plastid properties, and that red light and blue light evoke fundamentally different responses.

Chronic Artificial Blue-Enriched White Light Is an Effective Countermeasure to Delayed Circadian Phase and Neurobehavioral Decrements

PubMed Central

Najjar, Raymond P.; Wolf, Luzian; Taillard, Jacques; Schlangen, Luc J. M.; Salam, Alex

2014-01-01

Studies in Polar Base stations, where personnel have no access to sunlight during winter, have reported circadian misalignment, free-running of the sleep-wake rhythm, and sleep problems. Here we tested light as a countermeasure to circadian misalignment in personnel of the Concordia Polar Base station during the polar winter. We hypothesized that entrainment of the circadian pacemaker to a 24-h light-dark schedule would not occur in all crew members (n = 10) exposed to 100–300 lux of standard fluorescent white (SW) light during the daytime, and that chronic non-time restricted daytime exposure to melanopsin-optimized blue-enriched white (BE) light would establish an a stable circadian phase, in participants, together with increased cognitive performance and mood levels. The lighting schedule consisted of an alternation between SW lighting (2 weeks), followed by a BE lighting (2 weeks) for a total of 9 weeks. Rest-activity cycles assessed by actigraphy showed a stable rest-activity pattern under both SW and BE light. No difference was found between light conditions on the intra-daily stability, variability and amplitude of activity, as assessed by non-parametric circadian analysis. As hypothesized, a significant delay of about 30 minutes in the onset of melatonin secretion occurred with SW, but not with BE light. BE light significantly enhanced well being and alertness compared to SW light. We propose that the superior efficacy of blue-enriched white light versus standard white light involves melanopsin-based mechanisms in the activation of the non-visual functions studied, and that their responses do not dampen with time (over 9-weeks). This work could lead to practical applications of light exposure in working environment where background light intensity is chronically low to moderate (polar base stations, power plants, space missions, etc.), and may help design lighting strategies to maintain health, productivity, and personnel safety. PMID:25072880

Blue light (470 nm) effectively inhibits bacterial and fungal growth.

PubMed

De Lucca, A J; Carter-Wientjes, C; Williams, K A; Bhatnagar, D

2012-12-01

Blue light (470 nm) LED antimicrobial properties were studied alone against bacteria and with or without the food grade photosensitizer, erythrosine (ERY) against filamentous fungi. Leuconostoc mesenteroides (LM), Bacillus atrophaeus (BA) or Pseudomonas aeruginosa (PA) aliquots were exposed on nutrient agar plates to Array 1 (AR1, 0·2 mW cm(-2)) or Array 2 (AR2, 80 mW cm(-2)), which emitted impure or pure blue light (0-300 J cm(-2)), respectively. Inoculated control (room light only) plates were incubated (48 h) and colonies enumerated. The antifungal properties of blue light combined with ERY (11·4 and 22·8 μmol l(-1)) on Penicillium digitatum (PD) and Fusarium graminearum (FG) conidia were determined. Conidial controls consisted of: no light, room light-treated conidia and ERY plus room light. Light-treated (ERY + blue light) conidial samples were exposed only to AR2 (0-100 J cm(-2)), aliquots spread on potato dextrose agar plates, incubated (48 h, 30°C) and colonies counted. Blue light alone significantly reduced bacterial and FG viability. Combined with ERY, it significantly reduced PD viability. Blue light is lethal to bacteria and filamentous fungi although effectiveness is dependent on light purity, energy levels and microbial genus. Light from two arrays of different blue LEDs significantly reduced bacterial (Leuconostoc mesenteroides, Bacillus atrophaeus and Pseudomonas aeruginosa) viabilities. Significant in vitro viability loss was observed for the filamentous fungi, Penicillium digitatum and Fusarium graminearum when exposed to pure blue light only plus a photosensitizer. F. graminearum viability was significantly reduced by blue light alone. Results suggest that (i) the amount of significant loss in bacterial viability observed for blue light that is pure or with traces of other wavelengths is genus dependent and (ii) depending on fungal genera, pure blue light is fungicidal with or without a photosensitizer. © 2012 The Society for Applied Microbiology.

Daily Profiles of Light Exposure and Evening Use of Light-emitting Devices in Young Adults Complaining of a Delayed Sleep Schedule.

PubMed

Van der Maren, Solenne; Moderie, Christophe; Duclos, Catherine; Paquet, Jean; Daneault, Véronique; Dumont, Marie

2018-04-01

A number of factors can contribute to a delayed sleep schedule. An important factor could be a daily profile of light exposure favoring a later circadian phase. This study aimed to compare light exposure between 14 young adults complaining of a delayed sleep schedule and 14 matched controls and to identify possible associations between habitual light exposure and circadian phase. Exposure to white and blue light was recorded with ambulatory monitors for 7 consecutive days. Participants also noted their daily use of light-emitting devices before bedtime. Endogenous circadian phase was estimated with the dim light melatonin onset (DLMO) in the laboratory. The amplitude of the light-dark cycle to which the subjects were exposed was smaller in delayed than in control subjects, and smaller amplitude was associated with a later DLMO. Smaller amplitude was due to both decreased exposure in the daytime and increased exposure at night. Total exposure to blue light, but not to white light, was lower in delayed subjects, possibly due to lower exposure to blue-rich outdoor light. Lower daily exposure to blue light was associated with a later DLMO. Timing of relative increases and decreases of light exposure in relation to endogenous circadian phase was also compared between the 2 groups. In delayed subjects, there was a relatively higher exposure to white and blue light 2 h after DLMO, a circadian time with maximal phase-delaying effect. Delayed participants also had higher exposure to light 8 to 10 h after DLMO, which occurred mostly during their sleep episode but may have some phase-advancing effects. Self-reported use of light-emitting devices before bedtime was higher in delayed than in control subjects and was associated with a later DLMO. This study suggests that individuals complaining of a delayed sleep schedule engage in light-related behaviors favoring a later circadian phase and a later bedtime.

Radiative Energy Budgets of Phototrophic Surface-Associated Microbial Communities and their Photosynthetic Efficiency Under Diffuse and Collimated Light

PubMed Central

Lichtenberg, Mads; Brodersen, Kasper E.; Kühl, Michael

2017-01-01

We investigated the radiative energy budgets of a heterogeneous photosynthetic coral reef sediment and a compact uniform cyanobacterial biofilm on top of coastal sediment. By combining electrochemical, thermocouple and fiber-optic microsensor measurements of O2, temperature and light, we could calculate the proportion of the absorbed light energy that was either dissipated as heat or conserved by photosynthesis. We show, across a range of different incident light regimes, that such radiative energy budgets are highly dominated by heat dissipation constituting up to 99.5% of the absorbed light energy. Highest photosynthetic energy conservation efficiency was found in the coral sediment under low light conditions and amounted to 18.1% of the absorbed light energy. Additionally, the effect of light directionality, i.e., diffuse or collimated light, on energy conversion efficiency was tested on the two surface-associated systems. The effects of light directionality on the radiative energy budgets of these phototrophic communities were not unanimous but, resulted in local spatial differences in heat-transfer, gross photosynthesis, and light distribution. The light acclimation index, Ek, i.e., the irradiance at the onset of saturation of photosynthesis, was >2 times higher in the coral sediment compared to the biofilm and changed the pattern of photosynthetic energy conservation under light-limiting conditions. At moderate to high incident irradiances, the photosynthetic conservation of absorbed energy was highest in collimated light; a tendency that changed in the biofilm under sub-saturating incident irradiances, where higher photosynthetic efficiencies were observed under diffuse light. The aim was to investigate how the physical structure and light propagation affected energy budgets and light utilization efficiencies in loosely organized vs. compact phototrophic sediment under diffuse and collimated light. Our results suggest that the optical properties and the structural organization of phytoelements are important traits affecting the photosynthetic efficiency of biofilms and sediments. PMID:28400749

Radiative Energy Budgets of Phototrophic Surface-Associated Microbial Communities and their Photosynthetic Efficiency Under Diffuse and Collimated Light.

PubMed

Lichtenberg, Mads; Brodersen, Kasper E; Kühl, Michael

2017-01-01

We investigated the radiative energy budgets of a heterogeneous photosynthetic coral reef sediment and a compact uniform cyanobacterial biofilm on top of coastal sediment. By combining electrochemical, thermocouple and fiber-optic microsensor measurements of O 2 , temperature and light, we could calculate the proportion of the absorbed light energy that was either dissipated as heat or conserved by photosynthesis. We show, across a range of different incident light regimes, that such radiative energy budgets are highly dominated by heat dissipation constituting up to 99.5% of the absorbed light energy. Highest photosynthetic energy conservation efficiency was found in the coral sediment under low light conditions and amounted to 18.1% of the absorbed light energy. Additionally, the effect of light directionality, i.e., diffuse or collimated light, on energy conversion efficiency was tested on the two surface-associated systems. The effects of light directionality on the radiative energy budgets of these phototrophic communities were not unanimous but, resulted in local spatial differences in heat-transfer, gross photosynthesis, and light distribution. The light acclimation index, E k , i.e., the irradiance at the onset of saturation of photosynthesis, was >2 times higher in the coral sediment compared to the biofilm and changed the pattern of photosynthetic energy conservation under light-limiting conditions. At moderate to high incident irradiances, the photosynthetic conservation of absorbed energy was highest in collimated light; a tendency that changed in the biofilm under sub-saturating incident irradiances, where higher photosynthetic efficiencies were observed under diffuse light. The aim was to investigate how the physical structure and light propagation affected energy budgets and light utilization efficiencies in loosely organized vs. compact phototrophic sediment under diffuse and collimated light. Our results suggest that the optical properties and the structural organization of phytoelements are important traits affecting the photosynthetic efficiency of biofilms and sediments.

An Integrated, Evidence-Based Approach to Transitioning to Operations: Specifications for Future Replacement Lights on ISS

NASA Technical Reports Server (NTRS)

Leveton, Lauren; Brainard, George; Whitmire, Alexandra; Kubey, Alan; Maida, Jim; Bowen, Charles; Johnston, Smith

2010-01-01

The International Space Station (ISS) currently uses General Luminaire Assemblies (GLAs) as its primary light source. These GLAs are composed of fluorescent lighting and are integrated into the electrical system on Station. Seventy seven of these units are distributed throughout the vehicle, and many of the lights, having reached their lifespan, are no longer functional; while backup panels are available on orbit, it is anticipated that the supplies of fluorescents on the station will be exhausted by 2015. The ISS vehicle office is therefore preparing to replace all of the GLAs, with Solid State Light Assemblies (SSLAs) composed of white Light Emitting Diodes (LEDs). In the Spring of 2010, an announcement for the replacement lights was released. The announcement specified that proposed lighting systems should use LED technology, given certain power draw restrictions and no changes to how the lights are currently controlled (a central on/off switch per node, and a dial to turn on/off and increase brightness on each lighting unit). The replacement lights are to follow current specifications for brightness levels (lux) and color temperature (degrees Kelvin, or K). Reportedly, the lighting on orbit is dim and suboptimal. The average brightness of the lights (given all lights within a node are operational) is 291 lux; by comparison, recommended office lighting ranges from 200 to 500 lux, and daylight ranges on a typical overcast day, consists of 10,000 to 25,000 lux. Representatives from NASA Behavioral Health and Performance Element (BHP) and Human Factors and Habitability identified that maintaining current brightness levels limits visual acuity, work space, and the use of light as a countermeasure for improving circadian entrainment, hastening phase shifting, evoking acute alertness and enhancing performance. Revised lighting specifications are therefore needed to optimize the replacement lights for the ISS.

[Effects of light quality on the growth characteristics and biochemical component of Chlorella pyrenoidosa].

PubMed

Tang, Qing-Qing; Fang, Zhi-Guo; Ji, Wen-Wen; Xia, Hui-Long

2014-11-01

Effect of light quality, including red light, blue light, white light, red and blue mixing light with ratios of 8: 1, 8:2 and 8 : 3, on the growth characteristics and biochenmical composition of Chlorella pyrenoidosa was investigated based on light emitting diode (LED). Results showed that Chlorella pyrenoidosa grew best under blue light, and the optical density, specific growth rate and biomass of Chlorella pyrenoidosa was about 2.4, 0.10 d(-1) and 0.64 g x L(-1), respectively, while the optical density of Chlorella pyrenoidosa was between 1.0 and 1.7, the specific growth rate was between 0.07-0.10 d(-1) and the biomass was between 0.27 and 0.38 g x L(-1) under other light quality after 30 days of cultivation. Under blue light, the optical density, specific growth rate and biomass of Chlorella pyrenoidosa was approximately 2.05 times, 1.33 times and 2.06 times higher than red light, respectively. Moreover, red and blue mixing light was conducive to the synthesis of chlorophyll a and β-carotene of Chlorella pyrenoidosa, and blue light could promote the synthesis of chlorophyll b. Chlorophyll a and carotenoids content of Chlorella pyrenoidosa was 13.5 mg xg(-1) and 5.8 mg x g(-1) respectively under red and blue mixing light with a ratio of 8:1, while it was 8.4 mg x g(-1) and 3.6 mg x g(-1) respectively under blue light. Red and blue mixing light was more conducive to protein and total lipid content per dry cell of Chlorella pyrenoidosa. Protein and total lipid content was 489.3 mg x g(-1) and 311.2 mg x g(-1) under red and blue mixing light with a ratio of 8 : 3, while it was 400.9 mg x g(-1) and 231.9 mg x g(-1) respectively under blue light.

Blue-light filtering alters angiogenic signaling in human retinal pigmented epithelial cells culture model.

PubMed

Vila, Natalia; Siblini, Aya; Esposito, Evangelina; Bravo-Filho, Vasco; Zoroquiain, Pablo; Aldrees, Sultan; Logan, Patrick; Arias, Lluis; Burnier, Miguel N

2017-11-02

Light exposure and more specifically the spectrum of blue light contribute to the oxidative stress in Age-related macular degeneration (AMD). The purpose of the study was to establish whether blue light filtering could modify proangiogenic signaling produced by retinal pigmented epithelial (RPE) cells under different conditions simulating risk factors for AMD. Three experiments were carried out in order to expose ARPE-19 cells to white light for 48 h with and without blue light-blocking filters (BLF) in different conditions. In each experiment one group was exposed to light with no BLF protection, a second group was exposed to light with BLF protection, and a control group was not exposed to light. The ARPE-19 cells used in each experiment prior to light exposure were cultured for 24 h as follows: Experiment 1) Normoxia, Experiment 2) Hypoxia, and Experiment 3) Lutein supplemented media in normoxia. The media of all groups was harvested after light exposure for sandwich ELISA-based assays to quantify 10 pro-angiogenic cytokines. A significant decrease in angiogenin secretion levels and a significant increase in bFGF were observed following light exposure, compared to dark conditions, in both normoxia and hypoxia conditions. With the addition of a blue light-blocking filter in normoxia, a significant increase in angiogenin levels was observed. Although statistical significance was not achieved, blue light filters reduce light-induced secretion of bFGF and VEGF to near normal levels. This trend is also observed when ARPE-19 cells are grown under hypoxic conditions and when pre-treated with lutein prior to exposure to experimental conditions. Following light exposure, there is a decrease in angiogenin secretion by ARPE-19 cells, which was abrogated with a blue light - blocking filter. Our findings support the position that blue light filtering affects the secretion of angiogenic factors by retinal pigmented epithelial cells under normoxic, hypoxic, and lutein-pretreated conditions in a similar manner.

Plant lighting system with five wavelength-band light-emitting diodes providing photon flux density and mixing ratio control

PubMed Central

2012-01-01

Background Plant growth and development depend on the availability of light. Lighting systems therefore play crucial roles in plant studies. Recent advancements of light-emitting diode (LED) technologies provide abundant opportunities to study various plant light responses. The LED merits include solidity, longevity, small element volume, radiant flux controllability, and monochromaticity. To apply these merits in plant light response studies, a lighting system must provide precisely controlled light spectra that are useful for inducing various plant responses. Results We have developed a plant lighting system that irradiated a 0.18 m2 area with a highly uniform distribution of photon flux density (PFD). The average photosynthetic PFD (PPFD) in the irradiated area was 438 micro-mol m–2 s–1 (coefficient of variation 9.6%), which is appropriate for growing leafy vegetables. The irradiated light includes violet, blue, orange-red, red, and far-red wavelength bands created by LEDs of five types. The PFD and mixing ratio of the five wavelength-band lights are controllable using a computer and drive circuits. The phototropic response of oat coleoptiles was investigated to evaluate plant sensitivity to the light control quality of the lighting system. Oat coleoptiles irradiated for 23 h with a uniformly distributed spectral PFD (SPFD) of 1 micro-mol m–2 s–1 nm–1 at every peak wavelength (405, 460, 630, 660, and 735 nm) grew almost straight upwards. When they were irradiated with an SPFD gradient of blue light (460 nm peak wavelength), the coleoptiles showed a phototropic curvature in the direction of the greater SPFD of blue light. The greater SPFD gradient induced the greater curvature of coleoptiles. The relation between the phototropic curvature (deg) and the blue-light SPFD gradient (micro-mol m–2 s–1 nm–1 m–1) was 2 deg per 1 micro-mol m–2 s–1 nm–1 m–1. Conclusions The plant lighting system, with a computer with a graphical user interface program, can control the PFD and mixing ratios of five wavelength-band lights. A highly uniform PFD distribution was achieved, although an intentionally distorted PFD gradient was also created. Phototropic responses of oat coleoptiles to the blue light gradient demonstrated the merit of fine controllability of this plant lighting system. PMID:23173915

Green light emitting curcumin dye in organic solvents

NASA Astrophysics Data System (ADS)

Mubeen, Mohammad; Deshmukh, Abhay D.; Dhoble, S. J.

2018-05-01

In this modern world, the demand for the white light emission has increased because of its wide applications in various display and lighting devices, sensors etc. This white light can be produced by mixing red, green and blue lights. Thus this green light can be produced from the plant extract i.e., Turmeric. Curcumin is the essential element present in turmeric to generate the green light. The Photoluminescence (PL) emission is observed at 540 nm at 380nm excitation. This method of generating green light is very simple, cost effective and efficient when compared to other methods.

Fiber optic spectroscopic digital imaging sensor and method for flame properties monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zelepouga, Serguei A; Rue, David M; Saveliev, Alexei V

2011-03-15

A system for real-time monitoring of flame properties in combustors and gasifiers which includes an imaging fiber optic bundle having a light receiving end and a light output end and a spectroscopic imaging system operably connected with the light output end of the imaging fiber optic bundle. Focusing of the light received by the light receiving end of the imaging fiber optic bundle by a wall disposed between the light receiving end of the fiber optic bundle and a light source, which wall forms a pinhole opening aligned with the light receiving end.

High-performance lighting evaluated by photobiological parameters.

PubMed

Rebec, Katja Malovrh; Gunde, Marta Klanjšek

2014-08-10

The human reception of light includes image-forming and non-image-forming effects which are triggered by spectral distribution and intensity of light. Ideal lighting is similar to daylight, which could be evaluated by spectral or chromaticity match. LED-based and CFL-based lighting were analyzed here, proposed according to spectral and chromaticity match, respectively. The photobiological effects were expressed by effectiveness for blue light hazard, cirtopic activity, and photopic vision. Good spectral match provides light with more similar effects to those obtained by the chromaticity match. The new parameters are useful for better evaluation of complex human responses caused by lighting.

Evolving Our Evaluation of Luminous Environments

NASA Technical Reports Server (NTRS)

Clark, Toni

2016-01-01

The advance in solid state light emitting technologies and optics for lighting and visual communication necessitates the evaluation of how NASA envisions spacecraft lighting architectures and how NASA uses industry standards for the design and evaluation of lighting systems. Current NASA lighting standards and requirements for existing architectures focus on the separate ability of a lighting system to throw light against a surface or the ability of a display system to provide the appropriate visual contrast. This project investigated large luminous surface lamps as an alternative or supplement to overhead lighting. The efficiency of the technology was evaluated for uniformity and power consumption.

Fiberoptic spectrophotometer

DOEpatents

Tans, Petrus P.; Lashof, Daniel A.

1986-01-01

A device for determining the relative composition of a sample of a gas by comparison of the Raman-scattered light of the sample with that of a known gas comprising: a means for passing a single light source through the unknown and the known gases, choppers to alternate the Raman-scattered light into a common light detection and measuring system, optical fiber networks for spatially mixing the resulting Raman scattered light from each sample and directing the mixed light to selective detectors, and a compiler to record the light intensity of each wavelength of Raman-scattered light as a function of the sample from which it originated.

Spectral effects of light-emitting diodes on plant growth and development: The importance of green and blue light

NASA Astrophysics Data System (ADS)

Cope, K. R.; Bugbee, B.

2011-12-01

Light-emitting diodes (LEDs) are an emerging technology for plant growth lighting. Due to their narrow spectral output, colored LEDs provide many options for studying the spectral effects of light on plants. Early on, efficient red LEDs were the primary focus of photobiological research; however, subsequent studies have shown that normal plant growth and development cannot be achieved under red light without blue light supplementation. More recent studies have shown that red and blue (RB) LEDs supplemented with green light increase plant dry mass. This is because green light transmits more effectively through the leaf canopy than red and blue light, thus illuminating lower plant leaves and increasing whole-plant photosynthesis. Red, green and blue (RGB) light can be provided by either a conventional white light source (such as fluorescent lights), a combination of RGB LEDs, or from recently developed white LEDs. White LEDs exceed the efficiency of fluorescent lights and have a comparable broad spectrum. As such, they have the potential to replace fluorescent lighting for growth-chamber-based crop production both on Earth and in space. Here we report the results of studies on the effects of three white LED types (warm, neutral and cool) on plant growth and development compared to combinations of RB and RGB LEDs. Plants were grown under two constant light intensities (200 and 500 μmol m-2 s-1). Temperature, environmental conditions and root-zone environment were uniformly maintained across treatments. Phytochrome photoequilbria and red/far-red ratios were similar among treatments and were comparable to conventional fluorescent lights. Blue light had a significant effect on both plant growth (dry mass gain) and development (dry mass partitioning). An increase in the absolute amount (μmol m-2 s-1) of blue light from 0-80 μmol m-2 s-1 resulted in a decrease in stem elongation, independent of the light intensity. However, an increase in the relative amount (%) of blue light caused a decrease in specific leaf area (leaf area per unit leaf mass). As the relative amount of blue light increased, chlorophyll concentration per unit leaf area increased, but chlorophyll concentration per unit leaf mass remained constant. The relative amount of blue light increased total dry mass in some species while it remained constant in others. An increase in the fraction of green light increased dry mass in radish. Overall, white LEDs provided a more uniform spectral distribution, reduced stem elongation and leaf area, and maintained or increased dry mass as compared to RB and RGB LEDs. Cool white LEDs are more electrically efficient than the other two white LEDs and have sufficient blue light for normal plant growth and development at both high and low light intensities. Compared to sunlight, cool white LEDs are perhaps deficient in red light and may therefore benefit from supplementation with red LEDs. Future studies will be conducted to test this hypothesis. These results have significant implication for LADA growth chambers which are currently used for vegetable production on the International Space Station.

Effects of light at night on laboratory animals and research outcomes.

PubMed

Emmer, Kathryn M; Russart, Kathryn L G; Walker, William H; Nelson, Randy J; DeVries, A Courtney

2018-06-28

Light has substantial influences on the physiology and behavior of most laboratory animals. As such, lighting conditions within animal rooms are potentially significant and often underappreciated variables within experiments. Disruption of the light/dark cycle, primarily by exposing animals to light at night (LAN), disturbs biological rhythms and has widespread physiological consequences because of mechanisms such as melatonin suppression, sympathetic stimulation, and altered circadian clock gene expression. Thus, attention to the lighting environment of laboratory animals and maintaining consistency of a light/dark cycle is imperative for study reproducibility. Light intensity, as well as wavelength, photoperiod, and timing, are all important variables. Although modern rodent facilities are designed to facilitate appropriate light cycling, there are simple ways to modify rooms to prevent extraneous light exposure during the dark period. Attention to lighting conditions of laboratory animals by both researchers and research care staff ensures best practices for maintaining animal welfare, as well as reproducibility of research results. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Backscatter absorption gas imaging systems and light sources therefore

DOEpatents

Kulp, Thomas Jan [Livermore, CA; Kliner, Dahv A. V. [San Ramon, CA; Sommers, Ricky [Oakley, CA; Goers, Uta-Barbara [Campbell, NY; Armstrong, Karla M [Livermore, CA

2006-12-19

The location of gases that are not visible to the unaided human eye can be determined using tuned light sources that spectroscopically probe the gases and cameras that can provide images corresponding to the absorption of the gases. The present invention is a light source for a backscatter absorption gas imaging (BAGI) system, and a light source incorporating the light source, that can be used to remotely detect and produce images of "invisible" gases. The inventive light source has a light producing element, an optical amplifier, and an optical parametric oscillator to generate wavelength tunable light in the IR. By using a multi-mode light source and an amplifier that operates using 915 nm pump sources, the power consumption of the light source is reduced to a level that can be operated by batteries for long periods of time. In addition, the light source is tunable over the absorption bands of many hydrocarbons, making it useful for detecting hazardous gases.

Morphological responses of wheat to blue light

NASA Technical Reports Server (NTRS)

Barnes, C.; Bugbee, B.

1992-01-01

Blue light significantly increased tillering in wheat (Triticum aestivum L.) plants grown at the same photosynthetic photon flux (PPF). Plants were grown under two levels of blue light (400-500 nm) in a controlled environment with continuous irradiation. Plants received either 50 micromoles m-2 s-1 of blue light or 2 micromoles m-2 s-1 blue light from filtered metal halide lamps at a total irradiance of 200 micromoles m-2 s-1 PPF (400-700 nm). Plants tillered an average of 25% more under the higher level of blue light. Blue light also caused a small, but consistent, increase in main culm development, measured as Haun stage. Leaf length was reduced by higher levels of blue light, while plant dry-mass was not significantly affected by blue light. Applying the principle of equivalent light action, the results suggest that tillering and leaf elongation are mediated by the blue-UV light receptor(s) because phytochrome photoequilibrium for each treatment were nearly identical.

Effect of laser speckle on light from laser diode-pumped phosphor-converted light sources.

PubMed

Aquino, Felipe; Jadwisienczak, Wojciech M; Rahman, Faiz

2017-01-10

Laser diode (LD) pumped white light sources are being developed as an alternative to light-emitting diode-pumped sources for high efficiency and/or high brightness applications. While several performance metrics of laser-pumped phosphor-converted light sources have been investigated, the effect of laser speckle has not been sufficiently explored. This paper describes our experimental studies on how laser speckle affects the behavior of light from laser-excited phosphor lamps. A single LD pumping a phosphor plate was the geometry explored in this work. Overall, our findings are that the down-converted light did not exhibit any speckle, whereas speckle was present in the residual pump light but much reduced from that in direct laser light. Furthermore, a thicker coating of small-grained phosphors served to effectively reduce speckle through static pump light diffusion in the phosphor coating. Our investigations showed that speckle is not of concern in illumination from LD-pumped phosphor-converted light sources.

Comparative effectiveness of light emitting diodes (LEDs) and Lasers in near infrared photoimmunotherapy

PubMed Central

Sato, Kazuhide; Watanabe, Rira; Hanaoka, Hirofumi; Nakajima, Takahito; Choyke, Peter L.; Kobayashi, Hisataka

2016-01-01

Near infrared photoimmunotherapy (NIR-PIT) is a new cancer treatment that combines the specificity of antibodies for targeting tumors with the toxicity induced by photosensitizers after exposure to near infrared (NIR) light. Herein we compare two NIR-light sources; light emitting diodes (LEDs) and Lasers, for their effectiveness in NIR-PIT. A photosensitizer, IRDye-700DX, conjugated to panitumumab (pan-IR700), was incubated with EGFR-expressing A431 and MDA-MB-468-luc cells. NIR-light was provided by LEDs or Lasers at the same light dose. Laser-light produced more cytotoxicity and greater reductions in IR700-fluorescence intensity than LED-light. Laser-light also produced more cytotoxicity in vivo in both cell lines. Assessment of super-enhanced permeability and retention (SUPR) effects were stronger with Laser than LED. These results suggest that Laser-light produced significantly more cytotoxic effects compared to LEDs. Although LED is less expensive, Laser-light produces superior results in NIR-PIT. PMID:26885688

Artificial light pollution increases nocturnal vigilance in peahens

PubMed Central

Chisholm, Sarah; Byerley, Sydney D; Coy, Jeanee R.; Aziz, Aisyah; Wolf, Jamie A.; Gnerlich, Amanda C.

2015-01-01

Artificial light pollution is drastically changing the sensory environments of animals. Even though many animals are now living in these changed environments, the effect light pollution has on animal behavior is poorly understood. We investigated the effect of light pollution on nocturnal vigilance in peahens (Pavo cristatus). Captive peahens were exposed to either artificial lighting or natural lighting at night. We employed a novel method to record their vigilance behavior by attaching accelerometers to their heads and continuously monitoring their large head movements. We found that light pollution significantly increases nocturnal vigilance in peahens. Furthermore, the birds faced a trade-off between vigilance and sleep at night: peahens that were more vigilant spent less time sleeping. Given the choice, peahens preferred to roost away from high levels of artificial lighting but showed no preference for roosting without artificial lighting or with low levels of artificial lighting. Our study demonstrates that light pollution can have a substantial impact on animal behavior that can potentially result in fitness consequences. PMID:26339552

Design of the optical structure of airfield in-pavement LED runway edge lights

NASA Astrophysics Data System (ADS)

Ma, Xiaodan; Yang, Jianhong; Peng, Jun; Li, Lei

2017-02-01

Airfield lighting system is an important aiding system of civil aviation airport that guarantees the taking off, landing, taxiing of airplanes at night, with low visibility, or under other complicated weather conditions. In-pavement LED runway edge lights, with the highest degree of light intensity, are the most important lights for safe civil aviation and are most difficult to design within airfield lighting system. With LED as the source of light and the secondary optical design as the core, in light of basic laws of Fresnel loss and total reflection and the principles of edge-ray etendue conservation and the conservation of energy to design major optical elements as lens, prism of the lamp, the in-pavement LED runway edge lights design successfully solves the designing problem of high-power, high-intensity LED airfield lights with narrow beam angle at closed environment. This success is of great significance for the improvement of LED airfield lighting system in China.

Luminescence- and nanoparticle-mediated increase of light absorption by photoreceptor cells: Converting UV light to visible light.

PubMed

Li, Lei; Sahi, Sunil K; Peng, Mingying; Lee, Eric B; Ma, Lun; Wojtowicz, Jennifer L; Malin, John H; Chen, Wei

2016-02-10

We developed new optic devices - singly-doped luminescence glasses and nanoparticle-coated lenses that convert UV light to visible light - for improvement of visual system functions. Tb(3+) or Eu(3+) singly-doped borate glasses or CdS-quantum dot (CdS-QD) coated lenses efficiently convert UV light to 542 nm or 613 nm wavelength narrow-band green or red light, or wide-spectrum white light, and thereby provide extra visible light to the eye. In zebrafish (wild-type larvae and adult control animals, retinal degeneration mutants, and light-induced photoreceptor cell degeneration models), the use of Tb(3+) or Eu(3+) doped luminescence glass or CdS-QD coated glass lenses provide additional visible light to the rod and cone photoreceptor cells, and thereby improve the visual system functions. The data provide proof-of-concept for the future development of optic devices for improvement of visual system functions in patients who suffer from photoreceptor cell degeneration or related retinal diseases.

Monolithically integrated Si gate-controlled light-emitting device: science and properties

NASA Astrophysics Data System (ADS)

Xu, Kaikai

2018-02-01

The motivation of this study is to develop a p-n junction based light emitting device, in which the light emission is conventionally realized using reverse current driving, by voltage driving. By introducing an additional terminal of insulated gate for voltage driving, a novel three-terminal Si light emitting device is described where both the light intensity and spatial light pattern of the device are controlled by the gate voltage. The proposed light emitting device employs injection-enhanced Si in avalanche mode where electric field confinement occurs in the corner of a reverse-biased p+n junction. It is found that, depending on the bias conditions, the light intensity is either a linear or a quadratic function of the applied gate voltage or the reverse-bias. Since the light emission is based on the avalanching mode, the Si light emitting device offers the potential for very large scale integration-compatible light emitters for inter- or intra-chip signal transmission and contactless functional testing of wafers.

Comparative effectiveness of light emitting diodes (LEDs) and Lasers in near infrared photoimmunotherapy.

PubMed

Sato, Kazuhide; Watanabe, Rira; Hanaoka, Hirofumi; Nakajima, Takahito; Choyke, Peter L; Kobayashi, Hisataka

2016-03-22

Near infrared photoimmunotherapy (NIR-PIT) is a new cancer treatment that combines the specificity of antibodies for targeting tumors with the toxicity induced by photosensitizers after exposure to near infrared (NIR) light. Herein we compare two NIR-light sources; light emitting diodes (LEDs) and Lasers, for their effectiveness in NIR-PIT. A photosensitizer, IRDye-700DX, conjugated to panitumumab (pan-IR700), was incubated with EGFR-expressing A431 and MDA-MB-468-luc cells. NIR-light was provided by LEDs or Lasers at the same light dose. Laser-light produced more cytotoxicity and greater reductions in IR700-fluorescence intensity than LED-light. Laser-light also produced more cytotoxicity in vivo in both cell lines. Assessment of super-enhanced permeability and retention (SUPR) effects were stronger with Laser than LED. These results suggest that Laser-light produced significantly more cytotoxic effects compared to LEDs. Although LED is less expensive, Laser-light produces superior results in NIR-PIT.

Energy-saving quality road lighting with colloidal quantum dot nanophosphors

NASA Astrophysics Data System (ADS)

Erdem, Talha; Kelestemur, Yusuf; Soran-Erdem, Zeliha; Ji, Yun; Demir, Hilmi Volkan

2014-12-01

Here the first photometric study of road-lighting white light-emitting diodes (WLEDs) integrated with semiconductor colloidal quantum dots (QDs) is reported enabling higher luminance than conventional light sources, specifically in mesopic vision regimes essential to street lighting. Investigating over 100 million designs uncovers that quality road-lighting QD-WLEDs, with a color quality scale and color rendering index ≥85, enables 13-35% higher mesopic luminance than the sources commonly used in street lighting. Furthermore, these QD-WLEDs were shown to be electrically more efficient than conventional sources with power conversion efficiencies ≥16-29%. Considering this fact, an experimental proof-of-concept QD-WLED was demonstrated, which is the first account of QD based color conversion custom designed for street lighting applications. The obtained white LED achieved the targeted mesopic luminance levels in accordance with the road lighting standards of the USA and the UK. These results indicate that road-lighting QD-WLEDs are strongly promising for energy-saving quality road lighting.

Apparatus for Direct Optical Fiber Through-Lens Illumination of Microscopy or Observational Objects

NASA Technical Reports Server (NTRS)

Kadogawa, Hiroshi (Inventor)

2001-01-01

In one embodiment of the invention, a microscope or other observational apparatus, comprises a hollow tube, a lens mounted to the tube, a light source and at least one flexible optical fiber having an input end and an output end. The input end is positioned to receive light from the light source, and the output end is positioned within the tube so as to directly project light along a straight path to the lens to illuminate an object to be viewed. The path of projected light is uninterrupted and free of light deflecting elements. By passing the light through the lens, the light can be diffused or otherwise defocused to provide more uniform illumination across the surface of the object, increasing the quality of the image of the object seen by the viewer. The direct undeflected and uninterrupted projection of light, without change of direction, eliminates the need for light-deflecting elements, such as beam-splitters, mirrors, prisms, or the like, to direct the projected light towards the object.

Artificial light pollution increases nocturnal vigilance in peahens.

PubMed

Yorzinski, Jessica L; Chisholm, Sarah; Byerley, Sydney D; Coy, Jeanee R; Aziz, Aisyah; Wolf, Jamie A; Gnerlich, Amanda C

2015-01-01

Artificial light pollution is drastically changing the sensory environments of animals. Even though many animals are now living in these changed environments, the effect light pollution has on animal behavior is poorly understood. We investigated the effect of light pollution on nocturnal vigilance in peahens (Pavo cristatus). Captive peahens were exposed to either artificial lighting or natural lighting at night. We employed a novel method to record their vigilance behavior by attaching accelerometers to their heads and continuously monitoring their large head movements. We found that light pollution significantly increases nocturnal vigilance in peahens. Furthermore, the birds faced a trade-off between vigilance and sleep at night: peahens that were more vigilant spent less time sleeping. Given the choice, peahens preferred to roost away from high levels of artificial lighting but showed no preference for roosting without artificial lighting or with low levels of artificial lighting. Our study demonstrates that light pollution can have a substantial impact on animal behavior that can potentially result in fitness consequences.

Concept of white light in stage lighting

NASA Astrophysics Data System (ADS)

Rinaldi, Mauricio R.

2002-06-01

In perceiving objects, generally we see them in a white light situation. But, actually, there is not an absolute white, in such a manner that the different light sources have a determined kind of white, what it is known as color temperature. Even the white light may be of different kinds (different color temperature), the individual mind tends to perceive it as the same kind of white, that is to say, there is in our mind a psychological function by which we operate an integration in the perception in order to do the object perceptually invariable. On the other hand, it is a common practice in stage lighting to use color light sources. It is a well known phenomenon that a color of light produces a change in the object color perception. However, when we go to theater, we see the objects as having their real color, even if the lighting is not white. In this paper the concept of white light in stage lighting is presented, showing its possibilities of aesthetical expression.

Association of plasma cell subsets in the bone marrow and free light chain concentrations in the serum of monoclonal gammopathy patients.

PubMed

Ayliffe, Michael John; Behrens, Judith; Stern, Simon; Sumar, Nazira

2012-08-01

This study investigated bone marrow plasma cell subsets and monoclonal free light chain concentrations in blood of monoclonal gammopathy patients. 54 bone marrow samples were stained by double immunofluorescence to enumerate cellular subsets making either intact monoclonal immunoglobulin or free light chains only. Blood taken at the same time was assayed for free light chains by an automated immunoassay. Patients were assigned to three cellular population categories: single intact monoclonal immunoglobulin (59%), dual monoclonal immunoglobulin and free light chain only (31%), or single free light chain only (9%). The median affected free light chain concentration of each group was 75 mg/l, 903 mg/l and 3320 mg/l, respectively, but with substantial overlap. In myeloma patients the difference in serum free light chain concentrations between patients with free light chain only marrow cells and those without was statistically significant. Serum free light chain levels >600 mg/l result mostly from marrow cells restricted to free light chain production.

Light diffusing fiber optic chamber

DOEpatents

Maitland, Duncan J.

2002-01-01

A light diffusion system for transmitting light to a target area. The light is transmitted in a direction from a proximal end to a distal end by an optical fiber. A diffusing chamber is operatively connected to the optical fiber for transmitting the light from the proximal end to the distal end and transmitting said light to said target area. A plug is operatively connected to the diffusing chamber for increasing the light that is transmitted to the target area.

Combinatorial Control of Light Induced Chromatin Remodeling and Gene Activation in Neurospora

PubMed Central

Sancar, Cigdem; Ha, Nati; Yilmaz, Rüstem; Tesorero, Rafael; Fisher, Tamas; Brunner, Michael; Sancar, Gencer

2015-01-01

Light is an important environmental cue that affects physiology and development of Neurospora crassa. The light-sensing transcription factor (TF) WCC, which consists of the GATA-family TFs WC1 and WC2, is required for light-dependent transcription. SUB1, another GATA-family TF, is not a photoreceptor but has also been implicated in light-inducible gene expression. To assess regulation and organization of the network of light-inducible genes, we analyzed the roles of WCC and SUB1 in light-induced transcription and nucleosome remodeling. We show that SUB1 co-regulates a fraction of light-inducible genes together with the WCC. WCC induces nucleosome eviction at its binding sites. Chromatin remodeling is facilitated by SUB1 but SUB1 cannot activate light-inducible genes in the absence of WCC. We identified FF7, a TF with a putative O-acetyl transferase domain, as an interaction partner of SUB1 and show their cooperation in regulation of a fraction of light-inducible and a much larger number of non light-inducible genes. Our data suggest that WCC acts as a general switch for light-induced chromatin remodeling and gene expression. SUB1 and FF7 synergistically determine the extent of light-induction of target genes in common with WCC but have in addition a role in transcription regulation beyond light-induced gene expression. PMID:25822411

General method to evaluate substrate surface modification techniques for light extraction enhancement of organic light emitting diodes

NASA Astrophysics Data System (ADS)

Krummacher, B. C.; Mathai, M. K.; Choong, V.; Choulis, S. A.; So, F.; Winnacker, A.

2006-09-01

The external light output of organic light emitting diodes (OLEDs) can be increased by modifying the light emitting surface. The apparent light extraction enhancement is given by the ratio between the efficiency of the unmodified device and the efficiency of the modified device. This apparent light extraction enhancement is dependent on the OLED architecture itself and is not the correct value to judge the effectiveness of a technique to enhance light outcoupling due to substrate surface modification. We propose a general method to evaluate substrate surface modification techniques for light extraction enhancement of OLEDs independent from the device architecture. This method is experimentally demonstrated using green electrophosphorescent OLEDs with different device architectures. The substrate surface of these OLEDs was modified by applying a prismatic film to increase light outcoupling from the device stack. It was demonstrated that the conventionally measured apparent light extraction enhancement by means of the prismatic film does not reflect the actual performance of the light outcoupling technique. Rather, by comparing the light extracted out of the prismatic film to that generated in the OLED layers and coupled into the substrate (before the substrate/air interface), a more accurate evaluation of light outcoupling enhancement can be achieved. Furthermore we show that substrate surface modification can change the output spectrum of a broad band emitting OLED.

Position Index for the Matrix Light Source

NASA Astrophysics Data System (ADS)

Takahashi, Hiroshi; Kobayashi, Yoshinori; Onda, Shou; Irikura, Takashi

It is expected that in the future white LEDs will be widely used in practical applications including replacing conventional lighting in offices and homes. The white LED light source of matrix arrangement is also considered in it. On the other hand, although now the unified glare rating (UGR) is widely used for evaluation of the discomfort glare of the interior lighting, UGR is a thing for a uniform light source, and its application to the matrix light sources that have non-uniform luminance has not been considered. The aim of this study is to clarify the position index which is one of element of UGR for the matrix light source. In this case, to apply the position index for a matrix light source to UGR, the concept of the revised position index is invented. As the preliminary experiment, method for measuring the position index was conducted, and as the experiment, position index for the matrix light source was conducted and compared with the uniform light source. The results of the experiments show that the position index is decided by the relative angle between line of sight and light source. It is also found that the matrix light source have larger position index than uniform light source. Furthermore, it is shown that the discomfort glare caused by a matrix light source can be evaluated by applying the revised position index to the UGR.

Pollution-free road lighting

NASA Astrophysics Data System (ADS)

Schreuder, Duco A.

They relate to reducing road accidents and some forms of crime but also enhance the social safety of residents and pedestrians and the amenity for residents. Road traffic in developing countries is much more hazardous than in industrialized countries. Accident rates in 'low' income countries may be as much as 35 times higher than in 'high' income countries. Thus, it might be much more cost-effective to light roads in the developing world than in the industrialized world. Fighting light pollution is more pressing in developing countries as most of the major high-class astronomical observatories are there. Astronomical observations are disturbed by light from outdoor lighting installations, part of which is scattered in the atmosphere to form 'sky glow'. The International Lighting Commission CIE has published a Technical Report giving general guidance for lighting designers and policy makers on the reduction of the sky glow. Lighting improves visibility, essential for almost all human activity. However, light that hits the road contributes to visibility only if it is reflected. In poorly designed lighting equipment much of the lumen output of the lamps is sent directly upwards. This can be avoided by properly defined light fittings. The light output of fittings is determined by their optical quality and by the installation maintenance factor. Open fittings are to be preferred. If mounted horizontally, they make street lighting with the least light pollution.

Effect of light wavelength on motility and magnetic sensibility of the magnetotactic multicellular prokaryote 'Candidatus Magnetoglobus multicellularis'.

PubMed

de Azevedo, Lyvia Vidinho; de Barros, Henrique Lins; Keim, Carolina Neumann; Acosta-Avalos, Daniel

2013-09-01

'Candidatus Magnetoglobus multicellularis' is a magnetotactic microorganism composed of several bacterial cells. Presently, it is the best known multicellular magnetotactic prokaryote (MMP). Recently, it has been observed that MMPs present a negative photoresponse to high intensity ultraviolet and violet-blue light. In this work, we studied the movement of 'Candidatus Magnetoglobus multicellularis' under low intensity light of different wavelengths, measuring the average velocity and the time to reorient its trajectory when the external magnetic field changes its direction (U-turn time). Our results show that the mean average velocity is higher for red light (628 nm) and lower for green light (517 nm) as compared to yellow (596 nm) and blue (469 nm) light, and the U-turn time decreased for green light illumination. The light wavelength velocity dependence can be understood as variation in flagella rotation speed, being increased by the red light and decreased by the green light relative to yellow and blue light. It is suggested that the dependence of the U-turn time on light wavelength can be considered a form of light-dependent magnetotaxis, because this time represents the magnetic sensibility of the magnetotactic microorganisms. The cellular and molecular mechanisms for this light-dependent velocity and magnetotaxis are unknown and deserve further studies to understand the biochemical interactions and the ecological roles of the different mechanisms of taxis in MMPs.

Light pollution: the possible consequences of excessive illumination on retina.

PubMed

Contín, M A; Benedetto, M M; Quinteros-Quintana, M L; Guido, M E

2016-02-01

Light is the visible part of the electromagnetic radiation within a range of 380-780 nm; (400-700 on primates retina). In vertebrates, the retina is adapted to capturing light photons and transmitting this information to other structures in the central nervous system. In mammals, light acts directly on the retina to fulfill two important roles: (1) the visual function through rod and cone photoreceptor cells and (2) non-image forming tasks, such as the synchronization of circadian rhythms to a 24 h solar cycle, pineal melatonin suppression and pupil light reflexes. However, the excess of illumination may cause retinal degeneration or accelerate genetic retinal diseases. In the last century human society has increased its exposure to artificial illumination, producing changes in the Light/Dark cycle, as well as in light wavelengths and intensities. Although, the consequences of unnatural illumination or light pollution have been underestimated by modern society in its way of life, light pollution may have a strong impact on people's health. The effects of artificial light sources could have direct consequences on retinal health. Constant exposure to different wavelengths and intensities of light promoted by light pollution may produce retinal degeneration as a consequence of photoreceptor or retinal pigment epithelium cells death. In this review we summarize the different mechanisms of retinal damage related to the light exposure, which generates light pollution.

Light pollution: the possible consequences of excessive illumination on retina

PubMed Central

Contín, M A; Benedetto, M M; Quinteros-Quintana, M L; Guido, M E

2016-01-01

Light is the visible part of the electromagnetic radiation within a range of 380–780 nm; (400–700 on primates retina). In vertebrates, the retina is adapted to capturing light photons and transmitting this information to other structures in the central nervous system. In mammals, light acts directly on the retina to fulfill two important roles: (1) the visual function through rod and cone photoreceptor cells and (2) non-image forming tasks, such as the synchronization of circadian rhythms to a 24 h solar cycle, pineal melatonin suppression and pupil light reflexes. However, the excess of illumination may cause retinal degeneration or accelerate genetic retinal diseases. In the last century human society has increased its exposure to artificial illumination, producing changes in the Light/Dark cycle, as well as in light wavelengths and intensities. Although, the consequences of unnatural illumination or light pollution have been underestimated by modern society in its way of life, light pollution may have a strong impact on people's health. The effects of artificial light sources could have direct consequences on retinal health. Constant exposure to different wavelengths and intensities of light promoted by light pollution may produce retinal degeneration as a consequence of photoreceptor or retinal pigment epithelium cells death. In this review we summarize the different mechanisms of retinal damage related to the light exposure, which generates light pollution. PMID:26541085

Analysis of energy efficient highway lighting retrofits.

DOT National Transportation Integrated Search

2015-06-01

Solid state lighting technology is advancing rapidly to a point where light emitting diode (LED) lighting : systems can be viable replacements for existing lighting systems using high pressure sodium (HPS). The : present report summarizes analyses co...

Lighting the Learning Environment.

ERIC Educational Resources Information Center

Fielding, Randall

2000-01-01

Explores the benefits and pitfalls of day lighting, indirect light, and full-spectrum lamps for general illumination and accent lighting in classrooms. Discussions include lighting considerations in areas where computers are used and fixture cost factors versus efficiency. (GR)

Flexible, liquid core light guide with focusing and light shaping attachments

DOEpatents

Wojcik, R.F.; Majewski, S.; Zorn, C.J.; Kross, B.

1999-04-20

A liquid light guide system for ultraviolet light is disclosed that has a light shaping arrangement for the emitted light, a stable liquid core and sheath and reliable and effective end closures. The end closures include a metal crimping arrangement that utilizes two layers of deformable materials to prevent cracking of endplugs. 19 figs.

Light up My Life

ERIC Educational Resources Information Center

Kellett, Sarah

2015-01-01

Simply stated, light is nature's way of transferring energy through space. Discussions of light usually refer to visible light, which is perceived by the human eye and is responsible for the sense of sight. We see however, only a small part of the light spectrum. Light connects us as we sit and tell yarns around camp fires. Yet, one in every four…

Projection screen having reduced ambient light scattering

DOEpatents

Sweatt, William C [Albuquerque, NM

2010-05-11

An apparatus and method for improving the contrast between incident projected light and ambient light reflected from a projection screen are described. The efficiency of the projection screen for reflection of the projected light remains high, while permitting the projection screen to be utilized in a brightly lighted room. Light power requirements from the projection system utilized may be reduced.

Discrete wavelength-locked external cavity laser

NASA Technical Reports Server (NTRS)

Pilgrim, Jeffrey S. (Inventor); Silver, Joel A. (Inventor)

2005-01-01

An external cavity laser (and method of generating laser light) comprising: a laser light source; means for collimating light output by the laser light source; a diffraction grating receiving collimated light; a cavity feedback mirror reflecting light received from the diffraction grating back to the diffraction grating; and means for reliably tuning the external cavity laser to discrete wavelengths.

14 CFR 29.1385 - Position light system installation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... position lights and the rear position light must make a single circuit. (e) Light covers and color filters. Each light cover or color filter must be at least flame resistant and may not change color or shape or... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Position light system installation. 29.1385...

14 CFR 27.1385 - Position light system installation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... position lights and the rear position light must make a single circuit. (e) Light covers and color filters. Each light cover or color filter must be at least flame resistant and may not change color or shape or... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Position light system installation. 27.1385...

Mobile lighting apparatus

DOEpatents

Roe, George Michael; Klebanoff, Leonard Elliott; Rea, Gerald W; Drake, Robert A; Johnson, Terry A; Wingert, Steven John; Damberger, Thomas A; Skradski, Thomas J; Radley, Christopher James; Oros, James M; Schuttinger, Paul G; Grupp, David J; Prey, Stephen Carl

2013-05-14

A mobile lighting apparatus includes a portable frame such as a moveable trailer or skid having a light tower thereon. The light tower is moveable from a stowed position to a deployed position. A hydrogen-powered fuel cell is located on the portable frame to provide electrical power to an array of the energy efficient lights located on the light tower.

Building Twilight "Light Sensors" to Study the Effects of Light Pollution on Fireflies

ERIC Educational Resources Information Center

Thancharoen, Anchana; Branham, Marc A.; Lloyd, James E.

2008-01-01

Light pollution negatively affects many nocturnal organisms. We outline two experiments that can be conducted by students to examine the effects of light pollution on firefly behavior. Inexpensive electronic light sensors, which are easy to construct and calibrate, are used to sample light levels along transects in spaces where fireflies are…

32 CFR 707.3 - Yard arm signaling lights.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 5 2010-07-01 2010-07-01 false Yard arm signaling lights. 707.3 Section 707.3... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.3 Yard arm signaling lights. Naval vessels may display, as a means of visual signaling, white all round lights at the ends of the yard arms. These lights...

32 CFR 707.3 - Yard arm signaling lights.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 5 2014-07-01 2014-07-01 false Yard arm signaling lights. 707.3 Section 707.3... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.3 Yard arm signaling lights. Naval vessels may display, as a means of visual signaling, white all round lights at the ends of the yard arms. These lights...

33 CFR 118.70 - Lights on swing bridges.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Lights on swing bridges. 118.70... LIGHTING AND OTHER SIGNALS § 118.70 Lights on swing bridges. (a) Swing span lights on through bridges. Each... an approaching vessel the swing span when closed will display three red lights on top of the span...

33 CFR 118.65 - Lights on fixed bridges.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Lights on fixed bridges. 118.65... LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable... range of two green lights, and each margin of each navigable channel will be marked by a red light...

33 CFR 118.65 - Lights on fixed bridges.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lights on fixed bridges. 118.65... LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable... range of two green lights, and each margin of each navigable channel will be marked by a red light...

7. INTERIOR OF LIVING ROOM SHOWING DISTINCTIVE 6LIGHT THREEPANEL DOOR, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. INTERIOR OF LIVING ROOM SHOWING DISTINCTIVE 6-LIGHT THREE-PANEL DOOR, ONE OF THE NARROW 4-LIGHT OVER 4-LIGHT, DOUBLE-HUNG WINDOWS FRAMING THE FRONT DOOR, AND THE PAIRED 6-LIGHT OVER 1-LIGHT, DOUBLE-HUNG WINDOWS. VIEW TO NORTHWEST. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA

33 CFR 118.70 - Lights on swing bridges.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Lights on swing bridges. 118.70... LIGHTING AND OTHER SIGNALS § 118.70 Lights on swing bridges. (a) Swing span lights on through bridges. Each... an approaching vessel the swing span when closed will display three red lights on top of the span...

32 CFR 707.3 - Yard arm signaling lights.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 32 National Defense 5 2012-07-01 2012-07-01 false Yard arm signaling lights. 707.3 Section 707.3... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.3 Yard arm signaling lights. Naval vessels may display, as a means of visual signaling, white all round lights at the ends of the yard arms. These lights...

33 CFR 118.65 - Lights on fixed bridges.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Lights on fixed bridges. 118.65... LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable... range of two green lights, and each margin of each navigable channel will be marked by a red light...

33 CFR 118.70 - Lights on swing bridges.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lights on swing bridges. 118.70... LIGHTING AND OTHER SIGNALS § 118.70 Lights on swing bridges. (a) Swing span lights on through bridges. Each... an approaching vessel the swing span when closed will display three red lights on top of the span...

32 CFR 707.3 - Yard arm signaling lights.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 5 2011-07-01 2011-07-01 false Yard arm signaling lights. 707.3 Section 707.3... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.3 Yard arm signaling lights. Naval vessels may display, as a means of visual signaling, white all round lights at the ends of the yard arms. These lights...

33 CFR 118.65 - Lights on fixed bridges.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Lights on fixed bridges. 118.65... LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable... range of two green lights, and each margin of each navigable channel will be marked by a red light...

32 CFR 707.3 - Yard arm signaling lights.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 5 2013-07-01 2013-07-01 false Yard arm signaling lights. 707.3 Section 707.3... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.3 Yard arm signaling lights. Naval vessels may display, as a means of visual signaling, white all round lights at the ends of the yard arms. These lights...

33 CFR 118.70 - Lights on swing bridges.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Lights on swing bridges. 118.70... LIGHTING AND OTHER SIGNALS § 118.70 Lights on swing bridges. (a) Swing span lights on through bridges. Each... an approaching vessel the swing span when closed will display three red lights on top of the span...

Portable lamp with dynamically controlled lighting distribution

DOEpatents

Siminovitch, Michael J.; Page, Erik R.

2001-01-01

A double lamp table or floor lamp lighting system has a pair of compact fluorescent lamps (CFLs) arranged vertically with a reflective septum in between. By selectively turning on one or both of the CFLs, down lighting, up lighting, or both up and down lighting is produced. The control system can also vary the light intensity from each CFL. The reflective septum insures that almost all the light produced by each lamp will be directed into the desired light distribution pattern which is selected and easily changed by the user. Planar compact fluorescent lamps, e.g. circular CFLs, particularly oriented horizontally, are preferable. CFLs provide energy efficiency. The lighting system may be designed for the home, hospitality, office or other environments.

Scanned Image Projection System Employing Intermediate Image Plane

NASA Technical Reports Server (NTRS)

DeJong, Christian Dean (Inventor); Hudman, Joshua M. (Inventor)

2014-01-01

In imaging system, a spatial light modulator is configured to produce images by scanning a plurality light beams. A first optical element is configured to cause the plurality of light beams to converge along an optical path defined between the first optical element and the spatial light modulator. A second optical element is disposed between the spatial light modulator and a waveguide. The first optical element and the spatial light modulator are arranged such that an image plane is created between the spatial light modulator and the second optical element. The second optical element is configured to collect the diverging light from the image plane and collimate it. The second optical element then delivers the collimated light to a pupil at an input of the waveguide.

Lighting design in the neonatal intensive care unit: practical applications of scientific principles.

PubMed

White, Robert D

2004-06-01

Meeting the varied lighting needs of infants, caregivers, and families has become more complex as our understanding of visual development and perception and the effect of light on circadian rhythms advances. Optimal lighting strategies are discussed for new unit construction, as well as modifications to consider for existing units. In either case, the key concept is that lighting should be provided for the individual needs of each person, rather than the full-room lighting schemes previously used. Ideas gleaned from nonhospital settings, re-introduction of natural light into the neonatal intensive care unit, and new devices such as light-emitting diodes will dramatically change the lighting and visual environment of future neonatal intensive care units.

The Phosphorylation State of the Drosophila TRP Channel Modulates the Frequency Response to Oscillating Light In Vivo

PubMed Central

Rhodes-Mordov, Elisheva; Katz, Ben; Oberegelsbacher, Claudia; Yasin, Bushra; Tzadok, Hanan; Huber, Armin

2017-01-01

Drosophila photoreceptors respond to oscillating light of high frequency (∼100 Hz), while the detected maximal frequency is modulated by the light rearing conditions, thus enabling high sensitivity to light and high temporal resolution. However, the molecular basis for this adaptive process is unclear. Here, we report that dephosphorylation of the light-activated transient receptor potential (TRP) ion channel at S936 is a fast, graded, light-dependent, and Ca2+-dependent process that is partially modulated by the rhodopsin phosphatase retinal degeneration C (RDGC). Electroretinogram measurements of the frequency response to oscillating lights in vivo revealed that dark-reared flies expressing wild-type TRP exhibited a detection limit of oscillating light at relatively low frequencies, which was shifted to higher frequencies upon light adaptation. Strikingly, preventing phosphorylation of the S936-TRP site by alanine substitution in transgenic Drosophila (trpS936A) abolished the difference in frequency response between dark-adapted and light-adapted flies, resulting in high-frequency response also in dark-adapted flies. In contrast, inserting a phosphomimetic mutation by substituting the S936-TRP site to aspartic acid (trpS936D) set the frequency response of light-adapted flies to low frequencies typical of dark-adapted flies. Light-adapted rdgC mutant flies showed relatively high S936-TRP phosphorylation levels and light–dark phosphorylation dynamics. These findings suggest that RDGC is one but not the only phosphatase involved in pS936-TRP dephosphorylation. Together, this study indicates that TRP channel dephosphorylation is a regulatory process that affects the detection limit of oscillating light according to the light rearing condition, thus adjusting dynamic processing of visual information under varying light conditions. SIGNIFICANCE STATEMENT Drosophila photoreceptors exhibit high temporal resolution as manifested in frequency response to oscillating light of high frequency (≤∼100 Hz). Light rearing conditions modulate the maximal frequency detected by photoreceptors, thus enabling them to maintain high sensitivity to light and high temporal resolution. However, the precise mechanisms for this process are not fully understood. Here, we show by combination of biochemistry and in vivo electrophysiology that transient receptor potential (TRP) channel dephosphorylation at a specific site is a fast, light-activated and Ca2+-dependent regulatory process. TRP dephosphorylation affects the detection limit of oscillating light according to the adaptation state of the photoreceptor cells by shifting the detection limit to higher frequencies upon light adaptation. This novel mechanism thus adjusts dynamic processing of visual information under varying light conditions. PMID:28314815

Enhancement of crop photosynthesis by diffuse light: quantifying the contributing factors

PubMed Central

Li, T.; Heuvelink, E.; Dueck, T. A.; Janse, J.; Gort, G.; Marcelis, L. F. M.

2014-01-01

Background and Aims Plants use diffuse light more efficiently than direct light. However, experimental comparisons between diffuse and direct light have been obscured by co-occurring differences in environmental conditions (e.g. light intensity). This study aims to analyse the factors that contribute to an increase in crop photosynthesis in diffuse light and to quantify their relative contribution under different levels of diffuseness at similar light intensities. The hypothesis is that the enhancement of crop photosynthesis in diffuse light results not only from the direct effects of more uniform vertical and horizontal light distribution in the crop canopy, but also from crop physiological and morphological acclimation. Methods Tomato (Solanum lycopersicum) crops were grown in three greenhouse compartments that were covered by glass with different degrees of light diffuseness (0, 45 and 71 % of the direct light being converted into diffuse light) while maintaining similar light transmission. Measurements of horizontal and vertical photosynthetic photon flux density (PPFD) distribution in the crop, leaf photosynthesis light response curves and leaf area index (LAI) were used to quantify each factor's contribution to an increase in crop photosynthesis in diffuse light. In addition, leaf temperature, photoinhibition, and leaf biochemical and anatomical properties were studied. Key Results The highest degree of light diffuseness (71 %) increased the calculated crop photosynthesis by 7·2 %. This effect was mainly attributed to a more uniform horizontal (33 % of the total effect) and vertical PPFD distribution (21 %) in the crop. In addition, plants acclimated to the high level of diffuseness by gaining a higher photosynthetic capacity of leaves in the middle of the crop and a higher LAI, which contributed 23 and 13 %, respectively, to the total increase in crop photosynthesis in diffuse light. Moreover, diffuse light resulted in lower leaf temperatures and less photoinhibition at the top of the canopy when global irradiance was high. Conclusions Diffuse light enhanced crop photosynthesis. A more uniform horizontal PPFD distribution played the most important role in this enhancement, and a more uniform vertical PPFD distribution and higher leaf photosynthetic capacity contributed more to the enhancement of crop photosynthesis than did higher values of LAI. PMID:24782436

Comparisons of luminaires: Efficacies and system design

NASA Technical Reports Server (NTRS)

Albright, L. D.; Both, A. J.

1994-01-01

Lighting designs for architectural (aesthetic) purposes, vision and safety, and plant growth have many features in common but several crucial ones that are not. The human eye is very sensitive to the color (wavelength) of light, whereas plants are less so. There are morphological reactions, particularly to the red and blue portions of the light spectrum but, in general, plants appear to accept and use light for photosynthesis everywhere over the PAR region of the spectrum. In contrast, the human eye interprets light intensity on a logarithmic scale, making people insensitive to significant differences of light intensity. As a rough rule, light intensity must change by 30 to 50% for the human eye to recognize the difference. Plants respond much more linearly to light energy, at least at intensities below photosynthetic saturation. Thus, intensity differences not noticeable to the human eye can have significant effects on total plant growth and yield, and crop timing. These factors make luminaire selection and lighting system design particularly important when designing supplemental lighting systems for plant growth. Supplemental lighting for plant growth on the scale of commercial greenhouses is a relatively expensive undertaking. Light intensities are often much higher than required for task (vision) lighting, which increases both installation and operating costs. However, and especially in the northern regions of the United States (and Canada, Europe, etc.), supplemental lighting during winter may be necessary to produce certain crops (e.g., tomatoes) and very useful to achieve full plant growth potential and crop timing with most other greenhouse crops. Operating costs over the life of a luminaire typically will exceed the initial investment, making lighting efficacy a major consideration. This report reviews tests completed to evaluate the efficiencies of various commercially-available High-Pressure Sodium luminaires, and then describes the results of using a commercial lighting design computer program, Lumen-Micro, to explore how to place luminaires within greenhouses and plant growth chambers to achieve light (PAR) uniformity and relatively high lighting efficacies. Several suggestions are presented which could encourage systematic design of plant lighting systems.

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

PubMed

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.

Effect of a combination of green and blue monochromatic light on broiler immune response.

PubMed

Zhang, Ziqiang; Cao, Jing; Wang, Zixu; Dong, Yulan; Chen, Yaoxing

2014-09-05

Our previous study suggested that green light or blue light would enhance the broiler immune response; this study was conducted to evaluate whether a combination of green and blue monochromatic light would result in improved immune response. A total of 192 Arbor Acre male broilers were exposed to white light, red light, green light, and blue light from 0 to 26 days. From 27 to 49 days, half of the broilers in green light and blue light were switched to blue light (G-B) and green light (B-G), respectively. The levels of anti-Newcastle disease virus (NDV) and anti-bovine serum albumin (BSA) IgG in G-B group were elevated by 11.9-40.3% and 17.4-48.7%, respectively, compared to single monochromatic lights (P<0.05). Moreover, the proliferation of peripheral blood T and B lymphocytes and the IL-2 concentration in the G-B groups increased by 10.4-36.2%, 10.0-50.0% and 24.7-60.3% (P<0.05), respectively, compared with the single monochromatic light groups. However, the serum TNF-α concentration in the G-B group was reduced by 3.64-40.5% compared to other groups, and no significant difference was found between the G-B and B-G groups in any type of detection index at the end of the experiment. These results suggested that the combination of G-B and B-G monochromatic light could effectively enhance the antibody titer, the proliferation index of lymphocytes and alleviate the stress response in broilers. Therefore, the combination of green and blue monochromatic light can improve the immune function of broilers. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of exposure to intermittent versus continuous red light on human circadian rhythms, melatonin suppression, and pupillary constriction.

PubMed

Ho Mien, Ivan; Chua, Eric Chern-Pin; Lau, Pauline; Tan, Luuan-Chin; Lee, Ivan Tian-Guang; Yeo, Sing-Chen; Tan, Sara Shuhui; Gooley, Joshua J

2014-01-01

Exposure to light is a major determinant of sleep timing and hormonal rhythms. The role of retinal cones in regulating circadian physiology remains unclear, however, as most studies have used light exposures that also activate the photopigment melanopsin. Here, we tested the hypothesis that exposure to alternating red light and darkness can enhance circadian resetting responses in humans by repeatedly activating cone photoreceptors. In a between-subjects study, healthy volunteers (n = 24, 21-28 yr) lived individually in a laboratory for 6 consecutive days. Circadian rhythms of melatonin, cortisol, body temperature, and heart rate were assessed before and after exposure to 6 h of continuous red light (631 nm, 13 log photons cm(-2) s(-1)), intermittent red light (1 min on/off), or bright white light (2,500 lux) near the onset of nocturnal melatonin secretion (n = 8 in each group). Melatonin suppression and pupillary constriction were also assessed during light exposure. We found that circadian resetting responses were similar for exposure to continuous versus intermittent red light (P = 0.69), with an average phase delay shift of almost an hour. Surprisingly, 2 subjects who were exposed to red light exhibited circadian responses similar in magnitude to those who were exposed to bright white light. Red light also elicited prolonged pupillary constriction, but did not suppress melatonin levels. These findings suggest that, for red light stimuli outside the range of sensitivity for melanopsin, cone photoreceptors can mediate circadian phase resetting of physiologic rhythms in some individuals. Our results also show that sensitivity thresholds differ across non-visual light responses, suggesting that cones may contribute differentially to circadian resetting, melatonin suppression, and the pupillary light reflex during exposure to continuous light.

Lighting Automation Flying an Earthlike Habitat

NASA Technical Reports Server (NTRS)

Clark, Toni A.; Kolomenski, Andrei

2017-01-01

Currently, spacecraft lighting systems are not demonstrating innovations in automation due to perceived costs in designing circuitry for the communication and automation of lights. The majority of spacecraft lighting systems employ lamps or zone specific manual switches and dimmers. This type of 'hardwired' solution does not easily convert to automation. With advances in solid state lighting, the potential to enhance a spacecraft habitat is lost if the communication and automation problem is not tackled. If we are to build long duration environments, which provide earth-like habitats, minimize crew time, and optimize spacecraft power reserves, innovation in lighting automation is a must. This project researched the use of the DMX512 communication protocol originally developed for high channel count lighting systems. DMX512 is an internationally governed, industry-accepted, lighting communication protocol with wide industry support. The lighting industry markets a wealth of hardware and software that utilizes DMX512, and there may be incentive to space certify the system. Our goal in this research is to enable the development of automated spacecraft habitats for long duration missions. To transform how spacecraft lighting environments are automated, our project conducted a variety of tests to determine a potential scope of capability. We investigated utilization and application of an industry accepted lighting control protocol, DMX512 by showcasing how the lighting system could help conserve power, assist with lighting countermeasures, and utilize spatial body tracking. We hope evaluation and the demonstrations we built will inspire other NASA engineers, architects and researchers to consider employing DMX512 "smart lighting" capabilities into their system architecture. By using DMX512 we will prove the 'wheel' does not need to be reinvented in terms of smart lighting and future spacecraft can use a standard lighting protocol to produce an effective, optimized and potentially earthlike habitat.

Separate and Simultaneous Adjustment of Light Qualities in a Real Scene

PubMed Central

Pont, Sylvia C.; Heynderick, Ingrid

2017-01-01

Humans are able to estimate light field properties in a scene in that they have expectations of the objects’ appearance inside it. Previously, we probed such expectations in a real scene by asking whether a “probe object” fitted a real scene with regard to its lighting. But how well are observers able to interactively adjust the light properties on a “probe object” to its surrounding real scene? Image ambiguities can result in perceptual interactions between light properties. Such interactions formed a major problem for the “readability” of the illumination direction and diffuseness on a matte smooth spherical probe. We found that light direction and diffuseness judgments using a rough sphere as probe were slightly more accurate than when using a smooth sphere, due to the three-dimensional (3D) texture. We here extended the previous work by testing independent and simultaneous (i.e., the light field properties separated one by one or blended together) adjustments of light intensity, direction, and diffuseness using a rough probe. Independently inferred light intensities were close to the veridical values, and the simultaneously inferred light intensity interacted somewhat with the light direction and diffuseness. The independently inferred light directions showed no statistical difference with the simultaneously inferred directions. The light diffuseness inferences correlated with but contracted around medium veridical values. In summary, observers were able to adjust the basic light properties through both independent and simultaneous adjustments. The light intensity, direction, and diffuseness are well “readable” from our rough probe. Our method allows “tuning the light” (adjustment of its spatial distribution) in interfaces for lighting design or perception research. PMID:28203350

Lighting Automation - Flying an Earthlike Habitat

NASA Technical Reports Server (NTRS)

Clark, Tori A. (Principal Investigator); Kolomenski, Andrei

2017-01-01

Currently, spacecraft lighting systems are not demonstrating innovations in automation due to perceived costs in designing circuitry for the communication and automation of lights. The majority of spacecraft lighting systems employ lamps or zone specific manual switches and dimmers. This type of 'hardwired' solution does not easily convert to automation. With advances in solid state lighting, the potential to enhance a spacecraft habitat is lost if the communication and automation problem is not tackled. If we are to build long duration environments, which provide earth-like habitats, minimize crew time, and optimize spacecraft power reserves, innovation in lighting automation is a must. This project researched the use of the DMX512 communication protocol originally developed for high channel count lighting systems. DMX512 is an internationally governed, industry-accepted, lighting communication protocol with wide industry support. The lighting industry markets a wealth of hardware and software that utilizes DMX512, and there may be incentive to space certify the system. Our goal in this research is to enable the development of automated spacecraft habitats for long duration missions. To transform how spacecraft lighting environments are automated, our project conducted a variety of tests to determine a potential scope of capability. We investigated utilization and application of an industry accepted lighting control protocol, DMX512 by showcasing how the lighting system could help conserve power, assist with lighting countermeasures, and utilize spatial body tracking. We hope evaluation and the demonstrations we built will inspire other NASA engineers, architects and researchers to consider employing DMX512 "smart lighting" capabilities into their system architecture. By using DMX512 we will prove the 'wheel' does not need to be reinvented in terms of smart lighting and future spacecraft can use a standard lighting protocol to produce an effective, optimized and potentially earthlike habitat.

Response of bats to light with different spectra: light-shy and agile bat presence is affected by white and green, but not red light.

PubMed

Spoelstra, Kamiel; van Grunsven, Roy H A; Ramakers, Jip J C; Ferguson, Kim B; Raap, Thomas; Donners, Maurice; Veenendaal, Elmar M; Visser, Marcel E

2017-05-31

Artificial light at night has shown a remarkable increase over the past decades. Effects are reported for many species groups, and include changes in presence, behaviour, physiology and life-history traits. Among these, bats are strongly affected, and how bat species react to light is likely to vary with light colour. Different spectra may therefore be applied to reduce negative impacts. We used a unique set-up of eight field sites to study the response of bats to three different experimental light spectra in an otherwise dark and undisturbed natural habitat. We measured activity of three bat species groups around transects with light posts emitting white, green and red light with an intensity commonly used to illuminate countryside roads. The results reveal a strong and spectrum-dependent response for the slow-flying Myotis and Plecotus and more agile Pipistrellus species, but not for Nyctalus and Eptesicus species. Plecotus and Myotis species avoided white and green light, but were equally abundant in red light and darkness. The agile, opportunistically feeding Pipistrellus species were significantly more abundant around white and green light, most likely because of accumulation of insects, but equally abundant in red illuminated transects compared to dark control. Forest-dwelling Myotis and Plecotus species and more synanthropic Pipistrellus species are thus least disturbed by red light. Hence, in order to limit the negative impact of light at night on bats, white and green light should be avoided in or close to natural habitat, but red lights may be used if illumination is needed. © 2017 The Author(s).

Circadian Behavioral Study: LED vs Cool White Fluorescent - 0.1, 1, 10, 40, 80 lux. Part 2

NASA Technical Reports Server (NTRS)

Holley, Daniel C.; Syrkin, N.; Mele, G.

2000-01-01

Currently, the light source most commonly used in animal habitat lighting is cool white fluorescent (CWF) light. It was the objective of this study to evaluate a novel LED light source for use in animal habitat lighting by comparing its effectiveness to CWF light in producing and maintaining a normal circadian entrainment. The LED and CWF lights had similar spectral power distributions. Sprague-Dawley rats (175-350 g) were kept individually in metabolic cages, under a strict lighting control: 4 days of acclimation at 12:12 LD, 14 days of 12:12 LD, 14 days of 24:0 LD (free-run), and finally 12:12 LD. Food and water were provided ad libitum. Three behavioral parameters were monitored continuously: gross locomotor activity, drinking, and feeding. Combined mean free run periods (tau) were (mean +/- SEM): 24.6 +/- 0.1 and 24.7 +/- 0.2 at 0.1 lux, 25.5 +/- 0.1 and 25.7 +/- 0.1 at 1.0 lux, 25.3 +/- 0.2 and 25.4 +/- 0.2 at 10 lux, 25.8 +/- 0.1 and 25.9 +/- 0.1 at 40 lux, and 25.9 +/- 0.1 and 25.9 +/- 0.1 at 80 lux, CWF and LED respectively. ANOVA found a significant effect (p < 0.05) due to light level, but no difference in tau between rats exposed to constant CWF light and rats exposed to constant LED light. This study has shown that LED light can produce the same entrainment pattern as a conventional CWT light at similar intensities (0.1, 1, 10, 40, and 80 lux). LED light sources may be a suitable replacement for conventional light sources used in animal habitat lighting while providing many mechanical and economical advantages.

A tuneable approach to uniform light distribution for artificial daylight photodynamic therapy.

PubMed

O'Mahoney, Paul; Haigh, Neil; Wood, Kenny; Brown, C Tom A; Ibbotson, Sally; Eadie, Ewan

2018-06-16

Implementation of daylight photodynamic therapy (dPDT) is somewhat limited by variable weather conditions. Light sources have been employed to provide artificial dPDT indoors, with low irradiances and longer treatment times. Uniform light distribution across the target area is key to ensuring effective treatment, particularly for large areas. A novel light source is developed with tuneable direction of light emission in order to meet this challenge. Wavelength composition of the novel light source is controlled such that the protoporphyrin-IX (PpIX) weighed spectra of both the light source and daylight match. The uniformity of the light source is characterised on a flat surface, a model head and a model leg. For context, a typical conventional PDT light source is also characterised. Additionally, the wavelength uniformity across the treatment site is characterised. The PpIX-weighted spectrum of the novel light source matches with PpIX-weighted daylight spectrum, with irradiance values within the bounds for effective dPDT. By tuning the direction of light emission, improvements are seen in the uniformity across large anatomical surfaces. Wavelength uniformity is discussed. We have developed a light source that addresses the challenges in uniform, multiwavelength light distribution for large area artificial dPDT across curved anatomical surfaces. Copyright © 2018. Published by Elsevier B.V.

Evaluating white LEDs for outdoor landscape lighting application

NASA Astrophysics Data System (ADS)

Shakir, Insiya; Narendran, Nadarajah

2002-11-01

A laboratory experiment was conducted to understand the acceptability of different white light emitting diodes (LEDs) for outdoor landscape lighting. The study used a scaled model setup. The scene was designed to replicate the exterior of a typical upscale suburban restaurant including the exterior facade of the building, an approach with steps, and a garden. The lighting was designed to replicate light levels commonly found in nighttime outdoor conditions. The model had a central dividing partition with symmetrical scenes on both sides for side-by-side evaluations of the two scenes with different light sources. While maintaining equal luminance levels and distribution between the two scenes, four types of light sources were evaluated. These include, halogen, phosphor white LED, and two white light systems using RGB LEDs. These light sources were tested by comparing two sources at a time placed side-by-side and by individual assessment of each lighting condition. The results showed that the RGB LEDs performed equal or better than the most widely used halogen light source in this given setting. A majority of the subjects found slightly dimmer ambient lighting to be more typical for restaurants and therefore found RGB LED and halogen light sources to be more inviting. The phosphor white LEDs made the space look brighter, however a majority of the subjects disliked them.

Advances in light-curing units: four generations of LED lights and clinical implications for optimizing their use: Part 2. From present to future.

PubMed

Shortall, Adrian C; Palin, Will M; Jacquot, Bruno; Pelissier, Bruno

2012-01-01

The first part of this series of two described the history of light curing in dentistry and developments in LED lights since their introduction over 20 years ago. Current second- and third-generation LED light units have progressively replaced their halogen lamp predecessors because of their inherent advantages. The background to this, together with the clinical issues relating to light curing and the possible solutions, are outlined in the second part of this article. Finally, the innovative features of what may be seen as the first of a new fourth-generation of LED lights are described and guidance is given for the practitioner on what factors to consider when seeking to purchase a new LED light activation unit. Adequate curing in depth is fundamental to clinical success with any light-activated restoration. To achieve this goal predictably, an appropriate light source needs to be combined with materials knowledge, requisite clinical skills and attention to detail throughout the entire restoration process. As dentists increasingly use light-cured direct composites to restore large posterior restorations they need to appreciate the issues central to effective and efficient light curing and to know what to look for when seeking to purchase a new light-curing unit.

Evaluating office lighting environments: Second-level analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, B.L.; Fisher, W.S.; Gillette, G.L.

1989-04-01

Data from a post-occupancy evaluation (POE) of 912 work stations with lighting power density (LPD), photometric, and occupant-response measures were examined in a detailed, second-level analysis. Seven types of lighting systems were identified with different combinations of direct and indirect ambient lighting, and task lighting and daylight. The mean illuminances at the primary task location were within the IES target values for office task with a range of mean illuminances from 32 to 75 fc, depending on the lighting system. The median LPD was about 2.36 watts/sq ft, with about one-third the work stations having LPD's at or below 2.0more » watts/sq ft. Although a majority of the occupants (69%) were satisfied about their lighting, the highest percentage of those expressing dissatisfaction (37%) with lighting had an indirect fluorescent furniture-mounted (IFFM) system. The negative reaction of so many people to the IFFM system suggests that the combination of task lighting with an indirect ambient system had an important influence on lighting satisfaction, even though task illuminances tended to be higher with the IFFM system. Concepts of lighting quality, visual health, and control were explored, as well as average luminance to explain the negative reactions to the combination of indirect lighting with furniture-mounted lighting.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, L. B.; Donohoe, S. P.; Jones, M. H.

This article reports on the testing and comparison of a prototype hydrogen fuel cell light tower (H2LT) and a conventional diesel-powered metal halide light trailer for use in road maintenance and construction activities. The prototype was originally outfitted with plasma lights and then with light-emitting diode (LED) luminaires. Light output and distribution, lighting energy efficiency (i.e., efficacy), power source thermal efficiency, and fuel costs are compared. The metal halide luminaires have 2.2 and 3.1 times more light output than the plasma and LED luminaires, respectively, but they require more power/lumen to provide that output. The LED luminaires have 1.6 timesmore » better light efficacy than either the metal halide or plasma luminaires. The light uniformity ratios produced by the plasma and LED towers are acceptable. The fuel cell thermal efficiency at the power required to operate the plasma lights is 48%, significantly higher than the diesel generator efficiency of 23% when operating the metal halide lights. Due to the increased efficiency of the fuel cell and the LED lighting, the fuel cost per lumen-hour of the H2LT is 62% of the metal halide diesel light tower assuming a kilogram of hydrogen is twice the cost of a gallon of diesel fuel.« less

Effect of evening exposure to bright or dim light after daytime bright light on absorption of dietary carbohydrates the following morning.

PubMed

Hirota, Naoko; Sone, Yoshiaki; Tokura, Hiromi

2010-01-01

We had previously reported on the effect of exposure to light on the human digestive system: daytime bright light exposure has a positive effect, whereas, evening bright light exposure has a negative effect on the efficiency of dietary carbohydrate absorption from the evening meal. These results prompted us to examine whether the light intensity to which subjects are exposed in the evening affects the efficiency of dietary carbohydrate absorption the following morning. In this study, subjects were exposed to either 50 lux (dim light conditions) or 2,000 lux (bright light conditions) in the evening for 9 h (from 15:00 to 24:00) after staying under bright light in the daytime (under 2,000 lux from 07:00 to 15:00). We measured unabsorbed dietary carbohydrates using the breath-hydrogen test the morning after exposure to either bright light or dim light the previous evening. Results showed that there was no significant difference between the two conditions in the amount of breath hydrogen. This indicates that evening exposure to bright or dim light after bright light exposure in the daytime has no varying effect on digestion or absorption of dietary carbohydrates in the following morning's breakfast.

The impacts of new street light technologies: experimentally testing the effects on bats of changing from low-pressure sodium to white metal halide

PubMed Central

Stone, Emma Louise; Wakefield, Andrew; Harris, Stephen; Jones, Gareth

2015-01-01

Artificial light at night is a major feature of anthropogenic global change and is increasingly recognized as affecting biodiversity, often negatively. On a global scale, newer technology white lights are replacing orange sodium lights to reduce energy waste. In 2009, Cornwall County Council (UK) commenced replacement of existing low-pressure sodium (LPS) high intensity discharge (HID) street lights with new Phillips CosmoPolis white ceramic metal halide street lights to reduce energy wastage. This changeover provided a unique collaborative opportunity to implement a before-after-control-impact field experiment to investigate the ecological effects of newly installed broad spectrum light technologies. Activity of the bat species Pipistrellus pipistrellus, P. pygmaeus and Nyctalus/Eptesicus spp. was significantly higher at metal halide than LPS lights, as found in other studies of bat activity at old technology (i.e. mercury vapour) white light types. No significant difference was found in feeding attempts per bat pass between light types, though more passes overall were recorded at metal halide lights. Species-specific attraction of bats to the metal halide lights could have cascading effects at lower trophic levels. We highlight the need for further research on possible ecosystem-level effects of light technologies before they are installed on a wide scale. PMID:25780239

Improving “color rendering” of LED lighting for the growth of lettuce

NASA Astrophysics Data System (ADS)

Han, Tao; Vaganov, Vitaliy; Cao, Shixiu; Li, Qiang; Ling, Lili; Cheng, Xiaoyao; Peng, Lingling; Zhang, Congzhi; Yakovlev, Alexey N.; Zhong, Yang; Tu, Mingjing

2017-04-01

Light plays a vital role on the growth and development of plant. On the base of white light with high color rendering to the benefit of human survival and life, we proposed to improve “color rendering” of LED lighting for accelerating the growth of lettuce. Seven spectral LED lights were adopted to irradiate the lettuces under 150 μmol·m-2·s-1 for a 16 hd-1 photoperiod. The leaf area and number profiles, plant biomass, and photosynthetic rate under the as-prepared LED light treatments were investigated. We let the absorption spectrum of fresh leaf be the emission spectrum of ideal light and then evaluate the “color rendering” of as-prepared LED lights by the Pearson product-moment correlation coefficient and CIE chromaticity coordinates. Under the irradiation of red-yellow-blue light with high correlation coefficient of 0.587, the dry weights and leaf growth rate are 2-3 times as high as the sharp red-blue light. The optimized LED light for lettuce growth can be presumed to be limited to the angle (about 75°) between the vectors passed through the ideal light in the CIE chromaticity coordinates. These findings open up a new idea to assess and find the optimized LED light for plant growth.

Smooth light extraction in lighting optical fibre

NASA Astrophysics Data System (ADS)

Fernandez-Balbuena, A. A.; Vazquez-Molini, D.; Garcia-Botella, A.; Martinez-Anton, J. C.; Bernabeu, E.

2011-10-01

Recent advances in LED technology have relegated the use of optical fibre for general lighting, but there are several applications where it can be used as scanners lighting systems, daylight, cultural heritage lighting, sensors, explosion risky spaces, etc. Nowadays the use of high intensity LED to inject light in optical fibre increases the possibility of conjugate fibre + LED for lighting applications. New optical fibres of plastic materials, high core diameter up to 12.6 mm transmit light with little attenuation in the visible spectrum but there is no an efficient and controlled way to extract the light during the fibre path. Side extracting fibres extracts all the light on 2π angle so is not well suited for controlled lighting. In this paper we present an extraction system for mono-filament optical fibre which provides efficient and controlled light distribution. These lighting parameters can be controlled with an algorithm that set the position, depth and shape of the optical extraction system. The extraction system works by total internal reflection in the core of the fibre with high efficiency and low cost. A 10 m length prototype is made with 45° sectional cuts in the fibre core as extraction system. The system is tested with a 1W white LED illuminator in one side.

Evaluation of light-emitting diode beacon light fixtures.

DOT National Transportation Integrated Search

2009-12-01

Rotating beacons containing filament light sources have long been used on highway maintenance trucks : to indicate the presence of the truck to other drivers. Because of advances in light-emitting diode (LED) : technologies, flashing lights containin...

Roadway lighting and driver safety

DOT National Transportation Integrated Search

2003-05-01

The objectives of this project were to: a)analyze the safety benefits associated with roadway lighting; b)determine the design of the lighting installation necessary to provide an adequate level of lighting; c)investigate how lighting affects the dri...

Effects of blue light on the circadian system and eye physiology

PubMed Central

Ferguson, Ian; Tsubota, Kazuo

2016-01-01

Light-emitting diodes (LEDs) have been used to provide illumination in industrial and commercial environments. LEDs are also used in TVs, computers, smart phones, and tablets. Although the light emitted by most LEDs appears white, LEDs have peak emission in the blue light range (400–490 nm). The accumulating experimental evidence has indicated that exposure to blue light can affect many physiologic functions, and it can be used to treat circadian and sleep dysfunctions. However, blue light can also induce photoreceptor damage. Thus, it is important to consider the spectral output of LED-based light sources to minimize the danger that may be associated with blue light exposure. In this review, we summarize the current knowledge of the effects of blue light on the regulation of physiologic functions and the possible effects of blue light exposure on ocular health. PMID:26900325

Light Requirement for Shoot Regeneration in Horseradish Hairy Roots 1

PubMed Central

Saitou, Tsutomu; Kamada, Hiroshi; Harada, Hiroshi

1992-01-01

Hairy roots of horseradish (Armoracia rusticana) were induced by inoculation with Agrobacterium rhizogenes harboring Ri plasmid and cultured on phytohormone-free Murashige and Skoog medium after eliminating the bacteria. Hairy roots grew vigorously and sometimes formed yellowish calli under dark conditions. On the other hand, growth of hairy roots stopped after several weeks of culture with light, then shoots were regenerated. Frequency of shoot formation from hairy roots increased as the culture period in light lengthened and the light intensity increased. The shoot regeneration was induced by treatment with white or red light, but not with far-red light. Shoot regeneration by red light was inhibited by following treatment with far-red light. Red and far-red light reversibly affected shoot regeneration. Excised roots of nontransformed plants grew quite slowly on phytohormone-free Murashige and Skoog medium and occasionally formed shoots under white light conditions. PMID:16669041

Light requirement for shoot regeneration in horseradish hairy roots.

PubMed

Saitou, T; Kamada, H; Harada, H

1992-08-01

Hairy roots of horseradish (Armoracia rusticana) were induced by inoculation with Agrobacterium rhizogenes harboring Ri plasmid and cultured on phytohormone-free Murashige and Skoog medium after eliminating the bacteria. Hairy roots grew vigorously and sometimes formed yellowish calli under dark conditions. On the other hand, growth of hairy roots stopped after several weeks of culture with light, then shoots were regenerated. Frequency of shoot formation from hairy roots increased as the culture period in light lengthened and the light intensity increased. The shoot regeneration was induced by treatment with white or red light, but not with far-red light. Shoot regeneration by red light was inhibited by following treatment with far-red light. Red and far-red light reversibly affected shoot regeneration. Excised roots of nontransformed plants grew quite slowly on phytohormone-free Murashige and Skoog medium and occasionally formed shoots under white light conditions.

Exposure to blue light during lunch break: effects on autonomic arousal and behavioral alertness.

PubMed

Yuda, Emi; Ogasawara, Hiroki; Yoshida, Yutaka; Hayano, Junichiro

2017-07-11

Exposures to melanopsin-stimulating (melanopic) component-rich blue light enhance arousal level. We examined their effects in office workers. Eight healthy university office workers were exposed to blue and orange lights for 30 min during lunch break on different days. We compared the effects of light color on autonomic arousal level assessed by heart rate variability (HRV) and behavioral alertness by psychomotor vigilance tests (PVT). Heart rate was higher and high-frequency (HF, 0.150.45 Hz) power of HRV was lower during exposure to the blue light than to orange light. No significant difference with light color was observed, however, in any HRV indices during PVT or in PVT performance after light exposure. Exposure to blue light during lunch break, compared with that to orange light, enhances autonomic arousal during exposure, but has no sustained effect on autonomic arousal or behavioral alertness after exposure.

Light Emitting Diodes and Astronomical Environments: Results from in situ Field Measurements

NASA Astrophysics Data System (ADS)

Craine, Brian L.; Craine, Eric R.

2015-05-01

Light emitting diode (LED) light fixtures are rapidly becoming industry standards for outdoor lighting. They are promoted on the strength of long lifetimes (hence economic efficiencies), low power requirements, directability, active brightness controls, and energy efficiency. They also tend to produce spectral shifts that are undesirable in astronomical settings, but which can be moderated by filters. LED lighting for continuous roadway and parking lot lighting is particularly popular, and many communities are in the process of retrofitting Low Pressure Sodium (LPS) and other lights by tens of thousands of new LED fixtures at a time. What is the impact of this process on astronomical observatories and on dark skies upon which amateur astronomers rely? We bypass modeling and predictions to make actual measurements of these lights in the field. We report on original ground, airborne, and satellite observations of LED lights and discuss their light budgets, zenith angle functions, and impacts on observatory environs.

Lighting Automation - Flying an Earthlike Habit Project

NASA Technical Reports Server (NTRS)

Falker, Jay; Howard, Ricky; Culbert, Christopher; Clark, Toni Anne; Kolomenski, Andrei

2017-01-01

Our proposal will enable the development of automated spacecraft habitats for long duration missions. Majority of spacecraft lighting systems employ lamps or zone specific switches and dimmers. Automation is not in the "picture". If we are to build long duration environments, which provide earth-like habitats, minimize crew time, and optimize spacecraft power reserves, innovation in lighting automation is a must. To transform how spacecraft lighting environments are automated, we will provide performance data on a standard lighting communication protocol. We will investigate utilization and application of an industry accepted lighting control protocol, DMX512. We will demonstrate how lighting automation can conserve power, assist with lighting countermeasures, and utilize spatial body tracking. By using DMX512 we will prove the "wheel" does not need to be reinvented in terms of smart lighting and future spacecraft can use a standard lighting protocol to produce an effective, optimized and potentially earthlike habitat.

Identification and mitigation of stray laser light in the Thomson scattering system on the Madison Symmetric Torus (MST).

PubMed

Jacobson, C M; Borchardt, M T; Den Hartog, D J; Falkowski, A F; Morton, L A; Thomas, M A

2016-11-01

The Thomson scattering diagnostic on the Madison Symmetric Torus (MST) records excessive levels of stray Nd:YAG laser light. Stray light saturates the 1064 nm spectral channel in all polychromators, which prevents absolute electron density measurements via Rayleigh scattering calibration. Furthermore, stray light contaminates adjacent spectral channels for r/a ≥ 0.75, which renders the diagnostic unable to make electron temperature measurements at these radii. In situ measurements of stray light levels during a vacuum vessel vent are used to identify stray light sources and strategies for reduction of stray light levels. Numerical modeling using Zemax OpticStudio supports these measurements. The model of the vacuum vessel and diagnostic includes synthetic collection optics to enable direct comparison of measured and simulated stray light levels. Modeling produces qualitatively similar stray light distributions to MST measurements, and quantifies the mitigation effects of stray light mitigation strategies prior to implementation.

Identification and mitigation of stray laser light in the Thomson scattering system on the Madison Symmetric Torus (MST)

NASA Astrophysics Data System (ADS)

Jacobson, C. M.; Borchardt, M. T.; Den Hartog, D. J.; Falkowski, A. F.; Morton, L. A.; Thomas, M. A.

2016-11-01

The Thomson scattering diagnostic on the Madison Symmetric Torus (MST) records excessive levels of stray Nd:YAG laser light. Stray light saturates the 1064 nm spectral channel in all polychromators, which prevents absolute electron density measurements via Rayleigh scattering calibration. Furthermore, stray light contaminates adjacent spectral channels for r/a ≥ 0.75, which renders the diagnostic unable to make electron temperature measurements at these radii. In situ measurements of stray light levels during a vacuum vessel vent are used to identify stray light sources and strategies for reduction of stray light levels. Numerical modeling using Zemax OpticStudio supports these measurements. The model of the vacuum vessel and diagnostic includes synthetic collection optics to enable direct comparison of measured and simulated stray light levels. Modeling produces qualitatively similar stray light distributions to MST measurements, and quantifies the mitigation effects of stray light mitigation strategies prior to implementation.

Effect of Light on Anthocyanin Levels in Submerged, Harvested Cranberry Fruit

PubMed Central

Singh, Bal Ram

2004-01-01

Anthocyanins are a group of plant antioxidants known for their therapeutic use. The effects of natural light, red light, and far-red light on individual as well as total anthocyanin content in cranberry fruit (Vaccinium macrocarpon Ait) were examined in an experimental setting designed to mimic water-harvesting conditions. The reversed-phase high-performance liquid chromatography (HPLC) method was used to separate and analyze the anthocyanins. In contrast to the case of the control sample that was kept in the dark, natural light increased the total anthocyanin level by 75.3% and 87.2% after 24 and 48 hours of water immersion, respectively. Red light and far-red light increased the total anthocyanin level by 41.5% and 34.7%, respectively. The amount of each individual anthocyanin increased differently under natural light, red light, and far-red light, suggesting that expressions of enzymes that catalyze the anthocyanin biosynthesis are regulated differently by environments. PMID:15577187

Dynamic control of supplemental lighting for greenhouse

NASA Astrophysics Data System (ADS)

Wang, Yuanxv; Wei, Ruihua; Xu, Lihong

2018-04-01

The development of light-emitting diodes (LED) technology to a large extent reduce the energy consumption of greenhouse, however, the light control methods to realize the energy saving still have great potential. The aim of this paper is to develop a more efficient control method of dynamic control of the LED top-lighting (TL) intensity and the LED inter-lighting (IL) intensity for the greatest economic benefits. A dynamic lighting control algorithm (DLC) based on model is proposed, which defines the economic benefit performance criterion of the supplemental lighting control. The optimal light intensity of TL and IL is calculated in real time according to the algorithm. The simulation shows that economic benefit can be increased by up to 107.35% compared to TL on-off control. It is concluded that DLC is a feasible supplemental light control method, especially under low natural light conditions.

Human vision is attuned to the diffuseness of natural light

PubMed Central

Morgenstern, Yaniv; Geisler, Wilson S.; Murray, Richard F.

2014-01-01

All images are highly ambiguous, and to perceive 3-D scenes, the human visual system relies on assumptions about what lighting conditions are most probable. Here we show that human observers' assumptions about lighting diffuseness are well matched to the diffuseness of lighting in real-world scenes. We use a novel multidirectional photometer to measure lighting in hundreds of environments, and we find that the diffuseness of natural lighting falls in the same range as previous psychophysical estimates of the visual system's assumptions about diffuseness. We also find that natural lighting is typically directional enough to override human observers' assumption that light comes from above. Furthermore, we find that, although human performance on some tasks is worse in diffuse light, this can be largely accounted for by intrinsic task difficulty. These findings suggest that human vision is attuned to the diffuseness levels of natural lighting conditions. PMID:25139864

Improved Heat Dissipation of High-Power LED Lighting by a Lens Plate with Thermally-Conductive Plastics.

PubMed

Lee, Dong Kyu; Park, Hyun Jung; Cha, Yu-Jung; Kim, Hyeong Jin; Kwak, Joon Seop

2018-03-01

The junction temperature of high-power LED lighting was reduced effectively using a lens plate made from a thermally-conductive plastics (TCP). TCP has an excellent thermal conductivity, approximately 5 times that of polymethylmethacrylate (PMMA). Two sets of high-power LED lighting were designed using a multi array LED package with a lens plate for thermal simulation. The difference between two models was the materials of the lens plate. The lens plates of first and second models were fabricated by PMMA (PMMA lighting) and TCP (TCP lighting), respectively. At the lens plate, the simulated temperature of the TCP lighting was higher than that of the PMMA lighting. Near the LED package, the temperature of the TCP lighting was 2 °C lower than that of the PMMA lighting. This was well matched with the measured temperature of the fabricated lighting with TCP and PMMA.

Photic effects on sustained performance

NASA Technical Reports Server (NTRS)

French, J.; Whitmore, J.; Hannon, P. J.; Brainard, G.; Schiflett, S.

1992-01-01

Research is described which evaluates manipulating environmental light intensity as a means to attenuate fatigue. A counter balanced, within-subjects design was used to compare nine male subjects exposed to dim (100 lux) and bright (3000 lux) light conditions. Oral temperature values were greater for the bright light group over the dim light condition. Melatonin levels were suppressed by bright light treatment. Also, the frequency of eye blink rate was less for subjects during bright over dim light exposure. Light exposure was without effect on subjective fatigue. However, irrespective of light condition, significant effects on confusion, fatigue, and vigor mood dimensions were found as a result of 30 hour sleep deprivation. The findings suggest that bright lights may be used to help sustain nocturnal activity otherwise susceptible to fatigue. Such findings may have implications for the lighting arrangements on space flights during the subjective night for astronauts.

Rapid Optical Shutter, Chopper, Modulator and Deflector

NASA Technical Reports Server (NTRS)

Danehy, Paul M. (Inventor)

2017-01-01

An optical device with a light source and a detector is provided. A digital micromirror device positioned between the detector and the light source may deflect light beams projected from the light source. An aperture in front of the detector may block an incoming light beam from the detector when the incoming light beam is incident on the detector outside of a passable incident range and including an aperture opening configured to pass the incoming light beam to the detector when the incoming light beam is incident on the detector within a passable incident range. The digital micromirror device may rotate between a first position causing the light beam to pass through the aperture opening and a second position causing the light beam to be blocked by the aperture. The optical device may be configured to operate as a shutter, chopper, modulator and/or deflector.

Dim light at night increases body mass of female mice.

PubMed

Aubrecht, Taryn G; Jenkins, Richelle; Nelson, Randy J

2015-05-01

During the past century, the prevalence of light at night has increased in parallel with obesity rates. Dim light at night (dLAN) increases body mass in male mice. However, the effects of light at night on female body mass remain unspecified. Thus, female mice were exposed to a standard light/dark (LD; 16 h light at ∼150 lux/8 h dark at ∼0 lux) cycle or to light/dim light at night (dLAN; 16 h light at ∼150 lux/8 h dim light at ∼5 lux) cycles for six weeks. Females exposed to dLAN increased the rate of change in body mass compared to LD mice despite reduced total food intake during weeks five and six, suggesting that dLAN disrupted circadian rhythms resulting in deranged metabolism.

Evaluation of OLED and edge-lit LED lighting panels

NASA Astrophysics Data System (ADS)

Mou, Xi; Narendran, Nadarajah; Zhu, Yiting; Freyssinier, Jean Paul

2016-09-01

Solid-state lighting (SSL) offers a new technology platform for lighting designers and end-users to illuminate spaces with low energy demand. Two types of SSL sources include organic light-emitting diodes (OLEDs) and light-emitting diodes (LEDs). OLED is an area light source, and its primary competing technology is the edge-lit LED panel. Generally, both of these technologies are considered similar in shape and appearance, but there is little understanding of how people perceive discomfort glare from large area light sources. The objective of this study was to evaluate discomfort glare for the two lighting technologies under similar operating conditions by gathering observers' reactions. The human factors study results showed no statistically significant difference in human response to discomfort glare between OLED and edge-lit LED panels when the two light sources produced the same lighting stimulus. This means both technologies appeared equally glary beyond a certain luminance.

Approaches to Study Light Effects on Brassinosteroid Sensitivity.

PubMed

Paulišić, Sandi; Molina-Contreras, Maria José; Roig-Villanova, Irma; Martínez-García, Jaime F

2017-01-01

Light perception and hormone signaling in plants are likely connected at multiple points. Light conditions, perceived by photoreceptors, control plant responses by altering hormone concentration, tissue sensitivity, or a combination of both. Whereas it is relatively straightforward to assess the light effects on hormone levels, hormone sensitivity is subjected to interpretation. In Arabidopsis thaliana seedlings, hypocotyl length is strongly affected by light conditions. As hypocotyl elongation also depends on brassinosteroids (BRs), assaying this response provides a valuable and easy way to measure the responsiveness of seedlings to BRs and the impact of light. We describe a simple protocol to evaluate the responsiveness of hypocotyls to commercial BRs and/or BR inhibitors under a range of light conditions. These assays can be used to establish whether light affects BR sensitivity or whether BRs affect light sensitivity. Overall, our protocol can be easily applied for deetiolation (under polychromatic or monochromatic light) and simulated shade treatments combined with BR treatments.

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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)

Apparatus and method for measuring the thickness of a semiconductor wafer

DOEpatents

Ciszek, Theodoer F.

1995-01-01

Apparatus for measuring thicknesses of semiconductor wafers, comprising: housing means for supporting a wafer in a light-tight environment; a light source mounted to the housing at one side of the wafer to emit light of a predetermined wavelength to normally impinge the wafer; a light detector supported at a predetermined distance from a side of the wafer opposite the side on which a light source impinges and adapted to receive light transmitted through the wafer; and means for measuring the transmitted light.

Light Visor

NASA Technical Reports Server (NTRS)

1993-01-01

Seasonal Affective Disorder is a form of depression brought on by reduced light. For some people, this can lead to clinical depression. NASA has conducted research in light therapy and employs it to help astronauts adjust internal rhythms during orbital flight. Dr. George Brainard, a medical researcher and NASA consultant, has developed a portable light therapy device, which is commercially available. The Light Visor allows continuous light therapy and can be powered by either batteries or electricity. Dr. Brainard continues to research various aspects of light therapy.

Individually tailored light intervention through closed eyelids to promote circadian alignment and sleep health

PubMed Central

Figueiro, Mariana G.

2016-01-01

Background Light is most effective at changing the timing of the circadian clock when applied close to the core body temperature minimum. The present study investigated, in a home setting, if individually tailored light treatment using flashing blue light delivered through closed eyelids during the early part of the sleep period delayed circadian phase and sleep in a population of healthy older adults and in those suffering from early awakening insomnia. Methods Twenty-eight participants (9 early awakening insomniacs) completed an 8-week, within-subjects study. Twice, participants collected data during two baseline weeks and one intervention week. During the intervention week, participants wore a flashing blue (active) or a flashing red (control) light mask during sleep. Light was expected to delay circadian phase. Saliva samples for dim light melatonin onset (DLMO) were collected at the end of each baseline and intervention week. Wrist actigraphy and Daysimeter, a calibrated light and activity meter, data were collected during the entire study. Results Compared to baseline, flashing blue light, but not flashing red light, significantly (p<0.05) delayed DLMO. The mean ± standard deviation phase shift (minutes) was 0:06 ± 0:30 for the flashing red light and 0:34 ± 0:30 for the flashing blue light. Compared to Day 1, sleep start times were significantly delayed (by approximately 46 minutes) at Day 7 after the flashing blue light. The light intervention did not affect sleep efficiency. Conclusions The present study demonstrated the feasibility of using light through closed eyelids during sleep for promoting circadian alignment and sleep health. PMID:26985450

Light at Night and Measures of Alertness and Performance: Implications for Shift Workers.

PubMed

Figueiro, Mariana G; Sahin, Levent; Wood, Brittany; Plitnick, Barbara

2016-01-01

Rotating-shift workers, particularly those working at night, are likely to experience sleepiness, decreased productivity, and impaired safety while on the job. Light at night has been shown to have acute alerting effects, reduce sleepiness, and improve performance. However, light at night can also suppress melatonin and induce circadian disruption, both of which have been linked to increased health risks. Previous studies have shown that long-wavelength (red) light exposure increases objective and subjective measures of alertness at night, without suppressing nocturnal melatonin. This study investigated whether exposure to red light at night would not only increase measures of alertness but also improve performance. It was hypothesized that exposure to both red (630 nm) and white (2,568 K) lights would improve performance but that only white light would significantly affect melatonin levels. Seventeen individuals participated in a 3-week, within-subjects, nighttime laboratory study. Compared to remaining in dim light, participants had significantly faster reaction times in the GO/NOGO test after exposure to both red light and white light. Compared to dim light exposure, power in the alpha and alpha-theta regions was significantly decreased after exposure to red light. Melatonin levels were significantly suppressed by white light only. Results show that not only can red light improve measures of alertness, but it can also improve certain types of performance at night without affecting melatonin levels. These findings could have significant practical applications for nurses; red light could help nurses working rotating shifts maintain nighttime alertness, without suppressing melatonin or changing their circadian phase. © The Author(s) 2015.

Migratory bats respond to artificial green light with positive phototaxis.

PubMed

Voigt, Christian C; Roeleke, Manuel; Marggraf, Lara; Pētersons, Gunārs; Voigt-Heucke, Silke L

2017-01-01

Artificial light at night is spreading worldwide at unprecedented rates, exposing strictly nocturnal animals such as bats to a novel anthropogenic stressor. Previous studies about the effect of artificial light on bats focused almost exclusively on non-migratory species, yet migratory animals such as birds are known to be largely affected by light pollution. Thus, we conducted a field experiment to evaluate if bat migration is affected by artificial light at night. In late summer, we presented artificial green light of 520 nm wavelength to bats that were migrating south along the shoreline of the Baltic Sea. Using a light on-off treatment, we observed that the activity of Pipistrellus nathusii and P. pygmaeus, the two most abundant migratory species at our site, increased by more than 50% in the light-on compared to the light-off treatment. We observed an increased number of feeding buzzes during the light-on compared to the light-off treatment for P. nathusii. However, feeding activity was low in general and did not increase disproportionately during the light-on treatment in relation to the overall echolocation call activity of bats. Further, P. nathusii were attracted towards the green light at a distance of about 23 m, which is way beyond the echolocation detection range for insects of Nathusius' bats. We therefore infer that migratory bats were not attracted to artificial green light because of high insect densities, but instead by positive phototaxis. We conclude that artificial light at night may potentially impact bat migration in a yet unrecognized way.

Use of an Autonomous Surface Vehicle reveals small-scale diel vertical migrations of zooplankton and susceptibility to light pollution under low solar irradiance.

PubMed

Ludvigsen, Martin; Berge, Jørgen; Geoffroy, Maxime; Cohen, Jonathan H; De La Torre, Pedro R; Nornes, Stein M; Singh, Hanumant; Sørensen, Asgeir J; Daase, Malin; Johnsen, Geir

2018-01-01

Light is a major cue for nearly all life on Earth. However, most of our knowledge concerning the importance of light is based on organisms' response to light during daytime, including the dusk and dawn phase. When it is dark, light is most often considered as pollution, with increasing appreciation of its negative ecological effects. Using an Autonomous Surface Vehicle fitted with a hyperspectral irradiance sensor and an acoustic profiler, we detected and quantified the behavior of zooplankton in an unpolluted light environment in the high Arctic polar night and compared the results with that from a light-polluted environment close to our research vessels. First, in environments free of light pollution, the zooplankton community is intimately connected to the ambient light regime and performs synchronized diel vertical migrations in the upper 30 m despite the sun never rising above the horizon. Second, the vast majority of the pelagic community exhibits a strong light-escape response in the presence of artificial light, observed down to 100 m. We conclude that artificial light from traditional sampling platforms affects the zooplankton community to a degree where it is impossible to examine its abundance and natural rhythms within the upper 100 m. This study underscores the need to adjust sampling platforms, particularly in dim-light conditions, to capture relevant physical and biological data for ecological studies. It also highlights a previously unchartered susceptibility to light pollution in a region destined to see significant changes in light climate due to a reduced ice cover and an increased anthropogenic activity.

Effects of seed mass on seedling success in Artocarpus heterophyllus L., a tropical tree species of north-east India

NASA Astrophysics Data System (ADS)

Khan, M. L.

2004-03-01

I examined the effects of seed mass on performance of seedlings of Artocarpus heterophyllus L. (Moraceae), a large evergreen late successional shade-tolerant tree species in three contrasting light conditions. Seed mass varied many fold from 1.5 to 14 g in A. heterophyllus. Germination and germination time showed a significant correlation with seed mass. Germination differed significantly among three light regimes (50%, 25% and 3%). Seed mass and light level significantly affected seedling survival. The seedlings that emerged from large seeds survived better than those from small seeds under all light regimes. Survival of seedlings was maximum in 25% light regime for all seed mass classes but did not differ significantly from that at 50% light regime. Survival was significantly lower in 3% light as compared to 50% and 25% light regimes. Seedling vigor (expressed in terms of seedling height, leaf area and dry weight) was also significantly affected by seed mass and light regimes. Seedlings that emerged from larger seeds and grew under 50% light regime produced the heaviest seedlings, while those resulting from smaller seeds and grown under 3% light regime produced the lightest seedlings. Resprouting capacity of seedlings after clipping was significantly affected by seed mass and light regime. Seedlings emerging from larger seeds were capable of resprouting several times successively. Resprouting was more pronounced under 50% and 25% light regimes as compared to 3% light. Success of A. heterophyllus regeneration appears to be regulated by an interactive effect of seed mass and light regime.

On two heuristic viewpoints concerning the study of light

NASA Astrophysics Data System (ADS)

Bi, Siwen

2015-02-01

It has been a debatable problem that what the essence of light is, and how it is produced. Since the modern times, as James Clerk Maxwell setting the theory of electromagnetic up, the mainstream consciousness was occupied gradually by the wave theory of light. But at the end of 19th century, a series experimental phenomenon weren't precisely explained by the wave theory of light such as photoelectric effect experiment. Then Albert Einstein published his famous paper "On a Heuristic Viewpoint Concerning the Production and Transformation of Light", which laid the foundation of light quantum hypothesis. While solving these problems perfectly, a new problem was caused that because the wave theory and the quantum theory are both applicable to interpret some of the experiment of light, what is the essence of light. This paper first outlines the history of optical development and current status, and states the difficulties and deficiencies of the study of light. Then we put forward the key concept of the paper called lightstring which consults some points of the theory of modern optics and physics which called the optical frequency comb and the string theory, then presents the essence of light based on the light string concept in order to make the concept of photons specific. And then we put forward the production mechanism of light ---- the String-Light effect based on the concept of light string. In this paper, we attempt to put forward a new idea of the study of the essence of light and the production mechanism of it.

Human Adolescent Phase Response Curves to Bright White Light.

PubMed

Crowley, Stephanie J; Eastman, Charmane I

2017-08-01

Older adolescents are particularly vulnerable to circadian misalignment and sleep restriction, primarily due to early school start times. Light can shift the circadian system and could help attenuate circadian misalignment; however, a phase response curve (PRC) to determine the optimal time for receiving light and avoiding light is not available for adolescents. We constructed light PRCs for late pubertal to postpubertal adolescents aged 14 to 17 years. Participants completed 2 counterbalanced 5-day laboratory sessions after 8 or 9 days of scheduled sleep at home. Each session included phase assessments to measure the dim light melatonin onset (DLMO) before and after 3 days of free-running through an ultradian light-dark (wake-sleep) cycle (2 h dim [~20 lux] light, 2 h dark). In one session, intermittent bright white light (~5000 lux; four 20-min exposures) was alternated with 10 min of dim room light once per day for 3 consecutive days. The time of light varied among participants to cover the 24-h day. For each individual, the phase shift to bright light was corrected for the free-run derived from the other laboratory session with no bright light. One PRC showed phase shifts in response to light start time relative to the DLMO and another relative to home sleep. Phase delay shifts occurred around the hours corresponding to home bedtime. Phase advances occurred during the hours surrounding wake time and later in the afternoon. The transition from delays to advances occurred at the midpoint of home sleep. The adolescent PRCs presented here provide a valuable tool to time bright light in adolescents.

Evaluation of light-emitting diode beacon light fixtures : final report.

DOT National Transportation Integrated Search

2009-12-01

Rotating beacons containing filament light sources have long been used on highway maintenance trucks : to indicate the presence of the truck to other drivers. Because of advances in light-emitting diode (LED) : technologies, flashing lights containin...

32 CFR 707.4 - Aircraft warning lights.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 5 2010-07-01 2010-07-01 false Aircraft warning lights. 707.4 Section 707.4... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.4 Aircraft warning lights. Naval vessels may display... light on each obstruction. ...

32 CFR 707.4 - Aircraft warning lights.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 5 2013-07-01 2013-07-01 false Aircraft warning lights. 707.4 Section 707.4... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.4 Aircraft warning lights. Naval vessels may display... light on each obstruction. ...

32 CFR 707.4 - Aircraft warning lights.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 5 2014-07-01 2014-07-01 false Aircraft warning lights. 707.4 Section 707.4... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.4 Aircraft warning lights. Naval vessels may display... light on each obstruction. ...

32 CFR 707.4 - Aircraft warning lights.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 32 National Defense 5 2012-07-01 2012-07-01 false Aircraft warning lights. 707.4 Section 707.4... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.4 Aircraft warning lights. Naval vessels may display... light on each obstruction. ...

32 CFR 707.4 - Aircraft warning lights.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 5 2011-07-01 2011-07-01 false Aircraft warning lights. 707.4 Section 707.4... RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.4 Aircraft warning lights. Naval vessels may display... light on each obstruction. ...

33 CFR 83.22 - Visibility of lights (Rule 22).

Code of Federal Regulations, 2010 CFR

2010-07-01

... or more in length: (1) A masthead light, 6 miles; (2) A sidelight, 3 miles; (3) A sternlight, 3 miles; (4) A towing light, 3 miles; (5) A white, red, green or yellow all-round light, 3 miles; and (6) A... yellow all-round light, 2 miles; and (6) A special flashing light, 2 miles. (c) Vessels of less than 12...

Studying the Effect of Light Quality on the Size of the Photosystem II Light Harvesting Complex

ERIC Educational Resources Information Center

Muhoz, Romualdo; Quiles, Maria J.

2003-01-01

In this article the effect of light quality on the size of the photosystem II (PSII) light harvesting complex (LHCII) is studied by measuring the chlorophyll fluorescence emitted by leaf sections of oat ("Avena sativa," var. Prevision) plants previously treated with either white light or with light filtered through blue, green, red or farred…

46 CFR 161.012-13 - Production tests and inspections.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ten lights from each lot of lights produced. Each lot must not exceed 1,000 lights. At least nine of the ten lights, when tested in accordance with the test described in § 161.012-11(c), must meet the... random sample of ten lights must be taken and tested. If less than nine of these lights meet the test...

40 CFR 86.097-9 - Emission standards for 1997 and later model year light-duty trucks.

Code of Federal Regulations, 2013 CFR

2013-07-01

....097-9 Emission standards for 1997 and later model year light-duty trucks. (a)(1) Standards—(i) Light... standards. (ii) Heavy light-duty trucks. (A) Exhaust emissions from 1997 and later model year heavy light... model year light-duty trucks from compliance at low altitude with the emission standards set forth in...

40 CFR 86.1811-09 - Emission standards for light-duty vehicles, light-duty trucks and medium-duty passenger vehicles.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Emission standards for light-duty vehicles, light-duty trucks and medium-duty passenger vehicles. 86.1811-09 Section 86.1811-09 Protection of... Vehicles § 86.1811-09 Emission standards for light-duty vehicles, light-duty trucks and medium-duty...

40 CFR 86.1811-10 - Emission standards for light-duty vehicles, light-duty trucks and medium-duty passenger vehicles.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Emission standards for light-duty vehicles, light-duty trucks and medium-duty passenger vehicles. 86.1811-10 Section 86.1811-10 Protection of... Vehicles § 86.1811-10 Emission standards for light-duty vehicles, light-duty trucks and medium-duty...

40 CFR 86.1811-10 - Emission standards for light-duty vehicles, light-duty trucks and medium-duty passenger vehicles.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Emission standards for light-duty vehicles, light-duty trucks and medium-duty passenger vehicles. 86.1811-10 Section 86.1811-10 Protection of... Vehicles § 86.1811-10 Emission standards for light-duty vehicles, light-duty trucks and medium-duty...

40 CFR 86.1811-09 - Emission standards for light-duty vehicles, light-duty trucks and medium-duty passenger vehicles.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Emission standards for light-duty vehicles, light-duty trucks and medium-duty passenger vehicles. 86.1811-09 Section 86.1811-09 Protection of... Vehicles § 86.1811-09 Emission standards for light-duty vehicles, light-duty trucks and medium-duty...

40 CFR Appendix Xviii to Part 86 - Statistical Outlier Identification Procedure for Light-Duty Vehicles and Light Light-Duty Trucks...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Statistical Outlier Identification Procedure for Light-Duty Vehicles and Light Light-Duty Trucks Certifying to the Provisions of Part 86... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES...

40 CFR Appendix Xviii to Part 86 - Statistical Outlier Identification Procedure for Light-Duty Vehicles and Light Light-Duty Trucks...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Statistical Outlier Identification Procedure for Light-Duty Vehicles and Light Light-Duty Trucks Certifying to the Provisions of Part 86... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES...

33 CFR 84.05 - Horizontal positioning and spacing of lights.

Code of Federal Regulations, 2011 CFR

2011-07-01

... forward light must be placed not more than one half of the length of the vessel from the stem. (b) On a... forward masthead lights. They shall be placed at or near the side of the vessel. (c) When the lights prescribed in Rule 27(b)(i) are placed vertically between the forward masthead light(s) and the after...

33 CFR 84.05 - Horizontal positioning and spacing of lights.

Code of Federal Regulations, 2010 CFR

2010-07-01

... forward light must be placed not more than one half of the length of the vessel from the stem. (b) On a... forward masthead lights. They shall be placed at or near the side of the vessel. (c) When the lights prescribed in Rule 27(b)(i) are placed vertically between the forward masthead light(s) and the after...

Compact light-emitting diode lighting ring for video-assisted thoracic surgery.

PubMed

Lu, Ming-Kuan; Chang, Feng-Chen; Wang, Wen-Zhe; Hsieh, Chih-Cheng; Kao, Fu-Jen

2014-01-01

In this work, a foldable ring-shaped light-emitting diode (LED) lighting assembly, designed to attach to a rubber wound retractor, is realized and tested through porcine animal experiments. Enabled by the small size and the high efficiency of LED chips, the lighting assembly is compact, flexible, and disposable while providing direct and high brightness lighting for more uniform background illumination in video-assisted thoracic surgery (VATS). When compared with a conventional fiber bundle coupled light source that is usually used in laparoscopy and endoscopy, the much broader solid angle of illumination enabled by the LED assembly allows greatly improved background lighting and imaging quality in VATS.

Light robotics: aiming towards all-optical nano-robotics

NASA Astrophysics Data System (ADS)

Glückstad, Jesper; Palima, Darwin; Banas, Andrew

2017-04-01

Light Robotics is a new field of research where ingredients from photonics, nanotechnology and biotechnology are put together in new ways to realize light-driven robotics at the smallest scales to solve major challenges primarily within the nanobio-domain but not limited hereto. Exploring the full potential of this new `drone-like' light-printed, light-driven, light-actuated micro- and nanorobotics in challenging geometries requires a versatile and real-time reconfigurable light addressing that can dynamically track a plurality of tiny tools in 3D to ensure real-time continuous light-delivery on the fly. Our latest developments in this new and exciting research area will be reviewed.

Heterodyne interferometer with angstrom-level periodic nonlinearity

DOEpatents

Schmitz, Tony L.; Beckwith, John F.

2005-01-25

Displacement measuring interferometer systems and methods are disclosed. One or more acousto-optic modulators for receiving a laser light beam from a laser light source can be utilized to split the laser light beam into two or more laser light beams, while spatially separating frequencies thereof. One or more reflective mechanisms can be utilized to reflect one or more of the laser light beams back to the acousto-optic modulator. Interference of two or more of the laser light beams generally at the acousto-optic modulator can provide an interfered laser light beam thereof. A detector for receiving the interfered laser light beam can be utilized to provide interferometer measurement data.

Transfer Printing Method to Obtain Polarized Light Emission in Organic Light-Emitting Device

NASA Astrophysics Data System (ADS)

Noh, Hee Yeon; Park, Chang-sub; Park, Ji-Sub; Kang, Shin-Won; Kim, Hak-Rin

2012-06-01

We demonstrate a transfer printing method to obtain polarized light emission in organic light-emitting devices (OLEDs). On a rubbed self-assembled monolayer (SAM), a spin-coated liquid crystalline light-emissive polymer is aligned along the rubbing direction because of the anisotropic interfacial intermolecular interaction. Owing to the low surface energy of the SAM surface, the light-emissive layer was easily transferred to a patterned poly(dimethylsiloxane) (PDMS) stamp surface without degrading the ordering. Finally, a polarized light-emissive OLED device was prepared by transferring the patterned light-emissive layer to the charge transport layer of the OLED structure.

Fiberoptic spectrophotometer

DOEpatents

Tans, P.P.; Lashof, D.A.

1986-12-23

A device is described for determining the relative composition of a sample of a gas by comparison of the Raman-scattered light of the sample with that of a known gas comprising: a means for passing a single light source through the unknown and the known gases, choppers to alternate the Raman-scattered light into a common light detection and measuring system, optical fiber networks for spatially mixing the resulting Raman scattered light from each sample and directing the mixed light to selective detectors, and a compiler to record the light intensity of each wavelength of Raman-scattered light as a function of the sample from which it originated. 6 figs.

Light adaptation of the unicellular red alga, Cyanidioschyzon merolae, probed by time-resolved fluorescence spectroscopy.

PubMed

Ueno, Yoshifumi; Aikawa, Shimpei; Kondo, Akihiko; Akimoto, Seiji

2015-08-01

Photosynthetic organisms change the quantity and/or quality of their pigment-protein complexes and the interactions among these complexes in response to light conditions. In the present study, we analyzed light adaptation of the unicellular red alga Cyanidioschyzon merolae, whose pigment composition is similar to that of cyanobacteria because its phycobilisomes (PBS) lack phycoerythrin. C. merolae were grown under different light qualities, and their responses were measured by steady-state absorption, steady-state fluorescence, and picosecond time-resolved fluorescence spectroscopies. Cells were cultivated under four monochromatic light-emitting diodes (blue, green, yellow, and red), and changes in pigment composition and energy transfer were observed. Cells grown under blue and green light increased their relative phycocyanin levels compared with cells cultured under white light. Energy-transfer processes to photosystem I (PSI) were sensitive to yellow and red light. The contribution of direct energy transfer from PBS to PSI increased only under yellow light, while red light induced a reduction in energy transfer from photosystem II to PSI and an increase in energy transfer from light-harvesting chlorophyll protein complex I to PSI. Differences in pigment composition, growth, and energy transfer under different light qualities are discussed.

Light Redirective Display Panel And A Method Of Making A Light Redirective Display Panel

DOEpatents

Veligdan, James T.

2005-07-26

An optical display panel which provides improved light intensity at a viewing angle by redirecting light emitting from the viewing screen, and a method of making a light redirective display panel, are disclosed. The panel includes an inlet face at one end for receiving light, and an outlet screen at an opposite end for displaying the light. The inlet face is defined at one end of a transparent body, which body may be formed by a plurality of waveguides, and the outlet screen is defined at an opposite end of the body. The screen includes light redirective elements at the outlet screen for re-directing light emitting from the outlet screen. The method includes stacking a plurality of glass sheets, with a layer of adhesive or epoxy between each sheet, curing the adhesive to form a stack, placing the stack against a saw and cutting the stack at two opposite ends to form a wedge-shaped panel having an inlet face and an outlet face, and forming at the outlet face a plurality of light redirective elements which direct light incident on the outlet face into a controlled light cone.

Light redirective display panel and a method of making a light redirective display panel

DOEpatents

Veligdan, James T.

2002-01-01

An optical display panel which provides improved light intensity at a viewing angle by redirecting light emitting from the viewing screen, and a method of making a light redirective display panel, are disclosed. The panel includes an inlet face at one end for receiving light, and an outlet screen at an opposite end for displaying the light. The inlet face is defined at one end of a transparent body, which body may be formed by a plurality of waveguides, and the outlet screen is defined at an opposite end of the body. The screen includes light redirective elements at the outlet screen for re-directing light emitting from the outlet screen. The method includes stacking a plurality of glass sheets, with a layer of adhesive or epoxy between each sheet, curing the adhesive to form a stack, placing the stack against a saw and cutting the stack at two opposite ends to form a wedge-shaped panel having an inlet face and an outlet face, and forming at the outlet face a plurality of light redirective elements which direct light incident on the outlet face into a controlled light cone.

Adaptation of light-harvesting functions of unicellular green algae to different light qualities.

PubMed

Ueno, Yoshifumi; Aikawa, Shimpei; Kondo, Akihiko; Akimoto, Seiji

2018-05-28

Oxygenic photosynthetic organisms perform photosynthesis efficiently by distributing captured light energy to photosystems (PSs) at an appropriate balance. Maintaining photosynthetic efficiency under changing light conditions requires modification of light-harvesting and energy-transfer processes. In the current study, we examined how green algae regulate their light-harvesting functions in response to different light qualities. We measured low-temperature time-resolved fluorescence spectra of unicellular green algae Chlamydomonas reinhardtii and Chlorella variabilis cells grown under different light qualities. By observing the delayed fluorescence spectra, we demonstrated that both types of green algae primarily modified the associations between light-harvesting chlorophyll protein complexes (LHCs) and PSs (PSII and PSI). Under blue light, Chlamydomonas transferred more energy from LHC to chlorophyll (Chl) located far from the PSII reaction center, while energy was transferred from LHC to PSI via different energy-transfer pathways in Chlorella. Under green light, both green algae exhibited enhanced energy transfer from LHCs to both PSs. Red light induced fluorescence quenching within PSs in Chlamydomonas and LHCs in Chlorella. In Chlorella, energy transfer from PSII to PSI appears to play an important role in balancing excitation between PSII and PSI.

Blue light-induced oxidative stress in live skin.

PubMed

Nakashima, Yuya; Ohta, Shigeo; Wolf, Alexander M

2017-07-01

Skin damage from exposure to sunlight induces aging-like changes in appearance and is attributed to the ultraviolet (UV) component of light. Photosensitized production of reactive oxygen species (ROS) by UVA light is widely accepted to contribute to skin damage and carcinogenesis, but visible light is thought not to do so. Using mice expressing redox-sensitive GFP to detect ROS, blue light could produce oxidative stress in live skin. Blue light induced oxidative stress preferentially in mitochondria, but green, red, far red or infrared light did not. Blue light-induced oxidative stress was also detected in cultured human keratinocytes, but the per photon efficacy was only 25% of UVA in human keratinocyte mitochondria, compared to 68% of UVA in mouse skin. Skin autofluorescence was reduced by blue light, suggesting flavins are the photosensitizer. Exposing human skin to the blue light contained in sunlight depressed flavin autofluorescence, demonstrating that the visible component of sunlight has a physiologically significant effect on human skin. The ROS produced by blue light is probably superoxide, but not singlet oxygen. These results suggest that blue light contributes to skin aging similar to UVA. Copyright © 2017 Elsevier Inc. All rights reserved.

The Involvement of the Oxidative Stress in Murine Blue LED Light-Induced Retinal Damage Model.

PubMed

Nakamura, Maho; Kuse, Yoshiki; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Hara, Hideaki

2017-01-01

The aim of study was to establish a mouse model of blue light emitting diode (LED) light-induced retinal damage and to evaluate the effects of the antioxidant N-acetylcysteine (NAC). Mice were exposed to 400 or 800 lx blue LED light for 2 h, and were evaluated for retinal damage 5 d later by electroretinogram amplitude and outer nuclear layer (ONL) thickness. Additionally, we investigated the effect of blue LED light exposure on shorts-wave-sensitive opsin (S-opsin), and rhodopsin expression by immunohistochemistry. Blue LED light induced light intensity dependent retinal damage and led to collapse of S-opsin and altered rhodopsin localization from inner and outer segments to ONL. Conversely, NAC administered at 100 or 250 mg/kg intraperitoneally twice a day, before dark adaptation and before light exposure. NAC protected the blue LED light-induced retinal damage in a dose-dependent manner. Further, blue LED light-induced decreasing of S-opsin levels and altered rhodopsin localization, which were suppressed by NAC. We established a mouse model of blue LED light-induced retinal damage and these findings indicated that oxidative stress was partially involved in blue LED light-induced retinal damage.

Spectral design flexibility of LED brings better life

NASA Astrophysics Data System (ADS)

Ou, Haiyan; Corell, Dennis; Ou, Yiyu; Poulsen, Peter B.; Dam-Hansen, Carsten; Petersen, Paul-Michael

2012-03-01

Light-emitting diodes (LEDs) are penetrating into the huge market of general lighting because they are energy saving and environmentally friendly. The big advantage of LED light sources, compared to traditional incandescent lamps and fluorescent light tubes, is the flexible spectral design to make white light using different color mixing schemes. The spectral design flexibility of white LED light sources will promote them for novel applications to improve the life quality of human beings. As an initial exploration to make use of the spectral design flexibility, we present an example: 'no blue' white LED light source for sufferers of disease Porphyria. An LED light source prototype, made of high brightness commercial LEDs applying an optical filter, was tested by a patient suffering from Porphyria. Preliminary results have shown that the sufferer could withstand the light source for much longer time than the standard light source. At last future perspectives on spectral design flexibility of LED light sources improving human being's life will be discussed, with focus on the light and health. The good health is ensured by the spectrum optimized so that vital hormones (melatonin and serotonin) are produced during times when they support human daily rhythm.

A light-induced shortcut in the planktonic microbial loop

NASA Astrophysics Data System (ADS)

Ptacnik, Robert; Gomes, Ana; Royer, Sarah-Jeanne; Berger, Stella A.; Calbet, Albert; Nejstgaard, Jens C.; Gasol, Josep M.; Isari, Stamatina; Moorthi, Stefanie D.; Ptacnikova, Radka; Striebel, Maren; Sazhin, Andrey F.; Tsagaraki, Tatiana M.; Zervoudaki, Soultana; Altoja, Kristi; Dimitriou, Panagiotis D.; Laas, Peeter; Gazihan, Ayse; Martínez, Rodrigo A.; Schabhüttl, Stefanie; Santi, Ioulia; Sousoni, Despoina; Pitta, Paraskevi

2016-07-01

Mixotrophs combine photosynthesis with phagotrophy to cover their demands in energy and essential nutrients. This gives them a competitive advantage under oligotropihc conditions, where nutrients and bacteria concentrations are low. As the advantage for the mixotroph depends on light, the competition between mixo- and heterotrophic bacterivores should be regulated by light. To test this hypothesis, we incubated natural plankton from the ultra-oligotrophic Eastern Mediterranean in a set of mesocosms maintained at 4 light levels spanning a 10-fold light gradient. Picoplankton (heterotrophic bacteria (HB), pico-sized cyanobacteria, and small-sized flagellates) showed the fastest and most marked response to light, with pronounced predator-prey cycles, in the high-light treatments. Albeit cell specific activity of heterotrophic bacteria was constant across the light gradient, bacterial abundances exhibited an inverse relationship with light. This pattern was explained by light-induced top-down control of HB by bacterivorous phototrophic eukaryotes (PE), which was evidenced by a significant inverse relationship between HB net growth rate and PE abundances. Our results show that light mediates the impact of mixotrophic bacterivores. As mixo- and heterotrophs differ in the way they remineralize nutrients, these results have far-reaching implications for how nutrient cycling is affected by light.

Effect of Light Quality on Stomatal Opening in Leaves of Xanthium strumarium L.

PubMed

Sharkey, T D; Raschke, K

1981-11-01

Flux response curves were determined at 16 wavelengths of light for the conductance for water vapor of the lower epidermis of detached leaves of Xanthium strumarium L. An action spectrum of stomatal opening resulted in which blue light (wavelengths between 430 and 460 nanometers) was nearly ten times more effective than red light (wavelengths between 630 and 680 nanometers) in producing a conductance of 15 centimoles per square meter per second. Stomata responded only slightly to green light. An action spectrum of stomatal responses to red light corresponded to that of CO(2) assimilation; the inhibitors of photosynthetic electron transport, cyanazine (2-chloro-4[1-cyano-1-methylethylamino]-6-ethylamino-s-triazine) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea, eliminated the response to red light. This indicates that light absorption by chlorophyll is the cause of stomatal sensitivity to red light. Determination of flux response curves on leaves in the normal position (upper epidermis facing the light) or in the inverted position (lower epidermis facing the light) led to the conclusion that the photoreceptors for blue as well as for red light are located on or near the surfaces of the leaves; presumably they are in the guard cells themselves.

Sleep patterns in Amazon rubber tappers with and without electric light at home.

PubMed

Moreno, C R C; Vasconcelos, S; Marqueze, E C; Lowden, A; Middleton, B; Fischer, F M; Louzada, F M; Skene, D J

2015-09-11

Today's modern society is exposed to artificial electric lighting in addition to the natural light-dark cycle. Studies assessing the impact of electric light exposure on sleep and its relation to work hours are rare due to the ubiquitous presence of electricity. Here we report a unique study conducted in two phases in a homogenous group of rubber tappers living and working in a remote area of the Amazon forest, comparing those living without electric light (n = 243 in first phase; n = 25 in second phase) to those with electric light at home (n = 97 in first phase; n = 17 in second phase). Questionnaire data (Phase 1) revealed that rubber tappers with availability of electric light had significantly shorter sleep on work days (30 min/day less) than those without electric light. Analysis of the data from the Phase 2 sample showed a significant delay in the timing of melatonin onset in workers with electric light compared to those without electric light (p < 0.01). Electric lighting delayed sleep onset and reduced sleep duration during the work week and appears to interfere with alignment of the circadian timing system to the natural light/dark cycle.

Mapping lightscapes: spatial patterning of artificial lighting in an urban landscape.

PubMed

Hale, James D; Davies, Gemma; Fairbrass, Alison J; Matthews, Thomas J; Rogers, Christopher D F; Sadler, Jon P

2013-01-01

Artificial lighting is strongly associated with urbanisation and is increasing in its extent, brightness and spectral range. Changes in urban lighting have both positive and negative effects on city performance, yet little is known about how its character and magnitude vary across the urban landscape. A major barrier to related research, planning and governance has been the lack of lighting data at the city extent, particularly at a fine spatial resolution. Our aims were therefore to capture such data using aerial night photography and to undertake a case study of urban lighting. We present the finest scale multi-spectral lighting dataset available for an entire city and explore how lighting metrics vary with built density and land-use. We found positive relationships between artificial lighting indicators and built density at coarse spatial scales, whilst at a local level lighting varied with land-use. Manufacturing and housing are the primary land-use zones responsible for the city's brightly lit areas, yet manufacturing sites are relatively rare within the city. Our data suggests that efforts to address light pollution should broaden their focus from residential street lighting to include security lighting within manufacturing areas.

Mapping Lightscapes: Spatial Patterning of Artificial Lighting in an Urban Landscape

PubMed Central

Hale, James D.; Davies, Gemma; Fairbrass, Alison J.; Matthews, Thomas J.; Rogers, Christopher D. F.; Sadler, Jon P.

2013-01-01

Artificial lighting is strongly associated with urbanisation and is increasing in its extent, brightness and spectral range. Changes in urban lighting have both positive and negative effects on city performance, yet little is known about how its character and magnitude vary across the urban landscape. A major barrier to related research, planning and governance has been the lack of lighting data at the city extent, particularly at a fine spatial resolution. Our aims were therefore to capture such data using aerial night photography and to undertake a case study of urban lighting. We present the finest scale multi-spectral lighting dataset available for an entire city and explore how lighting metrics vary with built density and land-use. We found positive relationships between artificial lighting indicators and built density at coarse spatial scales, whilst at a local level lighting varied with land-use. Manufacturing and housing are the primary land-use zones responsible for the city’s brightly lit areas, yet manufacturing sites are relatively rare within the city. Our data suggests that efforts to address light pollution should broaden their focus from residential street lighting to include security lighting within manufacturing areas. PMID:23671566