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

Corapcioglu, Gulcan; Gulgun, Mehmet Ali; Kisslinger, Kim

In this paper, flash sintering experiments were performed, for the first time, on sodium potassium niobate (KNN) ceramics. A theoretical density of 94% was achieved in 30 s under 250 V/cm electric-field at 990°C. These conditions are ~100°C lower and faster than the conventional sintering conditions. Grains tended to grow after 30 s. flash sintering duration under constant electric-field. Detailed microstructural and chemical investigations of the sample showed that there was inhomogenous Na, K distribution and it resembles a core–shell structure where K is more in the shell and Na is more in the core region. The inhomogenous distribution ofmore » Na and K was correlated with the doubling of the unit cell within the grain along 002 direction. Compositional equilibrium is achieved after a heat treatment at 1000°C for 4 h. Finally, the compositional variations appeared to have been linked to grain boundary melting during flash and consequent recrystallization as the sample cooled.« less

Flash microwave synthesis and sintering of nanosized La{sub 0.75}Sr{sub 0.25}Cr{sub 0.93}Ru{sub 0.07}o{sub 3-{delta}} for fuel cell application

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

Combemale, L., E-mail: lionel.combemale@u-bourgogne.f; Caboche, G.; Stuerga, D.

2009-10-15

Perovskite-oxide nanocrystals of La{sub 0.75}Sr{sub 0.25}Cr{sub 0.93}Ru{sub 0.07}O{sub 3-{delta}} with a mean size around 10 nm were prepared by microwave flash synthesis. This reaction was performed in alcoholic solution using metallic salts, sodium ethoxide and microwave autoclave. The obtained powder was characterised after purification by energy dispersive X-ray analysis (EDX), X-ray powder diffraction (XRD), BET adsorption technique, photon correlation spectroscopy (PCS) and transmission electron microscopy (TEM). The results show that integrated perovskite-type phase and uniform particle size were obtained in the microwave treated samples. At last the synthesised powder was directly used in a sintering process. A porous solid, inmore » accordance with the expected applications, was then obtained at low sintering temperature (1000 deg. C) without use of pore forming agent. - Graphical abstract: TEM photograph of La{sub 0.75}Sr{sub 0.25}Cr{sub 0.93}Ru{sub 0.07}O{sub 3-{delta}} obtained by microwave flash synthesis. This picture confirms the nanometric size of the ceramic particles.« less

Measurement of O and Ti atom displacements in TiO 2 during flash sintering experiments

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

Yoon, Bola; Yadav, Devinder; Raj, Rishi

In-situ flash experiments on rutile TiO 2 were performed at the synchrotron at the Brookhaven National Laboratory. Pair distribution function analysis of total X-ray scattering measurements yielded mean-square atomic displacements of oxygen and titanium atoms during the progression of the 3 stages of flash. The displacements are measured to be far greater for oxygen atoms than for titanium atoms. Thus, these large displacements may signal an “elastic softening” of the lattice, which, recently, has been predicted as a precursor to the onset of flash.

Measurement of O and Ti atom displacements in TiO 2 during flash sintering experiments

DOE PAGES

Yoon, Bola; Yadav, Devinder; Raj, Rishi; ...

2017-12-29

In-situ flash experiments on rutile TiO 2 were performed at the synchrotron at the Brookhaven National Laboratory. Pair distribution function analysis of total X-ray scattering measurements yielded mean-square atomic displacements of oxygen and titanium atoms during the progression of the 3 stages of flash. The displacements are measured to be far greater for oxygen atoms than for titanium atoms. Thus, these large displacements may signal an “elastic softening” of the lattice, which, recently, has been predicted as a precursor to the onset of flash.

Photothermally Activated Motion and Ignition Using Aluminum Nanoparticles

DTIC Science & Technology

2013-01-17

In comparison with alternative sources such as spark ignition,19 laser igni- tion,20 plasma ignition,21 plasma -assisted combustion,22 and combustion...energy-dispersive X-ray spectroscopy measurements of motion-only and afterignition products confirm significant Al oxidation occurs through sintering ...significant Al oxidation occurs through sintering and bursting after the flash exposure. Simulations suggest local heat generation is enhanced by LSPR. The

50 CFR 600.730 - Facilitation of enforcement.

Code of Federal Regulations, 2011 CFR

2011-10-01

... transmitted by flashing light directed at the vessel signaled. USCG units will normally use the flashing light... your vessel instantly.” (Period (.) means a short flash of light; dash (-) means a long flash of light... authorized officer using loudhailer, radiotelephone, flashing light signal, or other means constitutes prima...

50 CFR 600.730 - Facilitation of enforcement.

Code of Federal Regulations, 2010 CFR

2010-10-01

... transmitted by flashing light directed at the vessel signaled. USCG units will normally use the flashing light... your vessel instantly.” (Period (.) means a short flash of light; dash (-) means a long flash of light... authorized officer using loudhailer, radiotelephone, flashing light signal, or other means constitutes prima...

49 CFR 234.217 - Flashing light units.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Flashing light units. 234.217 Section 234.217..., Inspection, and Testing Maintenance Standards § 234.217 Flashing light units. (a) Each flashing light unit.... (b) Each flashing light unit shall be maintained to prevent dust and moisture from entering the...

49 CFR 234.217 - Flashing light units.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Flashing light units. 234.217 Section 234.217..., Inspection, and Testing Maintenance Standards § 234.217 Flashing light units. (a) Each flashing light unit.... (b) Each flashing light unit shall be maintained to prevent dust and moisture from entering the...

49 CFR 234.217 - Flashing light units.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Flashing light units. 234.217 Section 234.217... light units. (a) Each flashing light unit shall be properly positioned and aligned and shall be visible to a highway user approaching the crossing. (b) Each flashing light unit shall be maintained to...

Thermal and Electrical Characterization of Alumina Substrate for Microelectronic Applications

NASA Astrophysics Data System (ADS)

Ahmad, S.; Ibrahim, A.; Alias, R.; Shapee, S. M.; Ambak, Z.; Zakaria, S. Z.; Yahya, M. R.; Mat, A. F. A.

2010-03-01

This paper reports the effect of sintering temperature on thermal and electrical properties of alumina material as substrate for microelectronic devices. Alumina materials in the form of green sheet with 1 mm thickness were sintered at 1100° C, 1300° C and 1500° C for about 20 hours using heating and cooling rates of 2° C/min. The densities were measured using densitometer and the microstructures of the samples were analyzed using SEM micrographs. Meanwhile thermal and electrical properties of the samples were measured using flash method and impedance analyzer respectively. It was found that thermal conductivity and thermal diffusivity of the substrate increases as sintering temperature increases. It was found also that the dielectric constant of alumina substrate increases as the sintering temperature increases.

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.

50 CFR 300.5 - Facilitation of enforcement.

Code of Federal Regulations, 2010 CFR

2010-10-01

... transmitted by flashing light directed at the vessel signaled. USCG units will normally use the flashing light..., flashing light, flags, whistle, horn or other means constitutes prima facie evidence of the offense of... International Code of Signals, may be sent by flashing light by an enforcement unit when conditions do not allow...

50 CFR 300.5 - Facilitation of enforcement.

Code of Federal Regulations, 2011 CFR

2011-10-01

... transmitted by flashing light directed at the vessel signaled. USCG units will normally use the flashing light..., flashing light, flags, whistle, horn or other means constitutes prima facie evidence of the offense of... International Code of Signals, may be sent by flashing light by an enforcement unit when conditions do not allow...

49 CFR 234.253 - Flashing light units and lamp voltage.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Flashing light units and lamp voltage. 234.253....253 Flashing light units and lamp voltage. (a) Each flashing light unit shall be inspected when... with installation specifications. (b) Lamp voltage shall be tested when installed and at least once...

49 CFR 234.253 - Flashing light units and lamp voltage.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Flashing light units and lamp voltage. 234.253....253 Flashing light units and lamp voltage. (a) Each flashing light unit shall be inspected when... with installation specifications. (b) Lamp voltage shall be tested when installed and at least once...

49 CFR 234.253 - Flashing light units and lamp voltage.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Flashing light units and lamp voltage. 234.253....253 Flashing light units and lamp voltage. (a) Each flashing light unit shall be inspected when... with installation specifications. (b) Lamp voltage shall be tested when installed and at least once...

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.

Flash protection controller

DOEpatents

Galbraith, L.K.

1979-12-07

A controller provides a high voltage to maintain an electro-optic shutter in a transparent condition until a flash of light which would be harmful to personnel is sensed by a phototransistor. The controller then shorts the shutter to ground to minimize light transmission to the user and maintains light transmission at the pre-flash level for a predetermined time to allow the flash to subside. A log converter and differential trigger circuit keep the controller from being triggered by other light flashes which are not dangerous.

Flash protection controller

DOEpatents

Galbraith, Lee K.

1981-01-01

A controller provides a high voltage to maintain an electro-optic shutter in a transparent condition until a flash of light which would be harmful to personnel is sensed by a phototransistor. The controller then shorts the shutter to ground to minimize light transmission to the user and maintains light transmission at the pre-flash level for a predetermined time to allow the flash to subside. A log converter and differential trigger circuit keep the controller from being triggered by other light flashes which are not dangerous.

46 CFR 35.20-30 - Flashing the rays of a searchlight or other blinding light-T/ALL.

Code of Federal Regulations, 2012 CFR

2012-10-01

... VESSELS OPERATIONS Navigation § 35.20-30 Flashing the rays of a searchlight or other blinding light—T/ALL. No person shall flash, or cause to be flashed, the rays of a search light or other blinding light... 46 Shipping 1 2012-10-01 2012-10-01 false Flashing the rays of a searchlight or other blinding...

46 CFR 35.20-30 - Flashing the rays of a searchlight or other blinding light-T/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

... VESSELS OPERATIONS Navigation § 35.20-30 Flashing the rays of a searchlight or other blinding light—T/ALL. No person shall flash, or cause to be flashed, the rays of a search light or other blinding light... 46 Shipping 1 2010-10-01 2010-10-01 false Flashing the rays of a searchlight or other blinding...

46 CFR 35.20-30 - Flashing the rays of a searchlight or other blinding light-T/ALL.

Code of Federal Regulations, 2014 CFR

2014-10-01

... VESSELS OPERATIONS Navigation § 35.20-30 Flashing the rays of a searchlight or other blinding light—T/ALL. No person shall flash, or cause to be flashed, the rays of a search light or other blinding light... 46 Shipping 1 2014-10-01 2014-10-01 false Flashing the rays of a searchlight or other blinding...

46 CFR 35.20-30 - Flashing the rays of a searchlight or other blinding light-T/ALL.

Code of Federal Regulations, 2013 CFR

2013-10-01

... VESSELS OPERATIONS Navigation § 35.20-30 Flashing the rays of a searchlight or other blinding light—T/ALL. No person shall flash, or cause to be flashed, the rays of a search light or other blinding light... 46 Shipping 1 2013-10-01 2013-10-01 false Flashing the rays of a searchlight or other blinding...

46 CFR 35.20-30 - Flashing the rays of a searchlight or other blinding light-T/ALL.

Code of Federal Regulations, 2011 CFR

2011-10-01

... VESSELS OPERATIONS Navigation § 35.20-30 Flashing the rays of a searchlight or other blinding light—T/ALL. No person shall flash, or cause to be flashed, the rays of a search light or other blinding light... 46 Shipping 1 2011-10-01 2011-10-01 false Flashing the rays of a searchlight or other blinding...

33 CFR 117.1007 - Elizabeth River-Eastern Branch.

Code of Federal Regulations, 2013 CFR

2013-07-01

... closing the draw, the channel traffic lights will change from flashing green to flashing red, the horn... down to vessels, the channel traffic lights will continue to flash red. (6) When the rail traffic has... opening to vessel traffic. During the opening swing movement, the channel traffic lights will flash red...

33 CFR 117.1007 - Elizabeth River-Eastern Branch.

Code of Federal Regulations, 2014 CFR

2014-07-01

... closing the draw, the channel traffic lights will change from flashing green to flashing red, the horn... down to vessels, the channel traffic lights will continue to flash red. (6) When the rail traffic has... opening to vessel traffic. During the opening swing movement, the channel traffic lights will flash red...

33 CFR 117.1007 - Elizabeth River-Eastern Branch.

Code of Federal Regulations, 2011 CFR

2011-07-01

... closing the draw, the channel traffic lights will change from flashing green to flashing red, the horn... down to vessels, the channel traffic lights will continue to flash red. (6) When the rail traffic has... opening to vessel traffic. During the opening swing movement, the channel traffic lights will flash red...

33 CFR 117.1007 - Elizabeth River-Eastern Branch.

Code of Federal Regulations, 2012 CFR

2012-07-01

... closing the draw, the channel traffic lights will change from flashing green to flashing red, the horn... down to vessels, the channel traffic lights will continue to flash red. (6) When the rail traffic has... opening to vessel traffic. During the opening swing movement, the channel traffic lights will flash red...

49 CFR 234.253 - Flashing light units and lamp voltage.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Flashing light units and lamp voltage. 234.253... Maintenance, Inspection, and Testing Inspections and Tests § 234.253 Flashing light units and lamp voltage. (a... proper alignment and frequency of flashes in accordance with installation specifications. (b) Lamp...

49 CFR 234.253 - Flashing light units and lamp voltage.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Flashing light units and lamp voltage. 234.253... Maintenance, Inspection, and Testing Inspections and Tests § 234.253 Flashing light units and lamp voltage. (a... proper alignment and frequency of flashes in accordance with installation specifications. (b) Lamp...

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

Optimal flash rate and duty cycle for flashing visual indicators.

NASA Technical Reports Server (NTRS)

Markowitz, J.

1971-01-01

This experiment examined the ability of observers to determine, as quickly as possible, whether a visual indicator was steadily on or flashing. Six flash rates (periods) were combined factorially with three duty cycles (on-off ratios) to define 18 ?types' of intermittent signals. Experimental sessions were divided into six runs of 100 trials, each run utilizing one of the six flash rates. On any given trial in a run, the probability of a steady signal occurring was 0.5 and the probability of a flashing signal occurring was 0.5. A different duty cycle was employed daily for each experimental session. In all, 400 trials were devoted to each of the flash rates at each duty cycle. Accuracy and latency of response were the dependent variables of interest. The results show that the observers view the light for an interval of time appropriate to the expected flash rate and duty cycle; whether they judge the light to be steady or intermittent depends upon whether the light is extinguished during the predetermined waiting period. Adoption of this temporal criterion delays responding in comparison to those tasks involving responses to light onset. The decision or response criteria held by the observers are also sensitive to the parameters of the flashing light: observers become increasingly willing to call a flashing light ?steady' as flash duration increases.

Experimental effective intensity of steady and flashing light emitting diodes for aircraft anti-collision lighting.

DOT National Transportation Integrated Search

2013-08-01

Research was conducted to determine the effective intensity of flashing lights that incorporate light-emitting diodes (LEDs). LEDs require less power and have the ability to flash without the addition of moving parts. Compared with incandescent bulbs...

Photography in Dermatologic Surgery: Selection of an Appropriate Lighting Solution for a Particular Clinical Application.

PubMed

Chen, Brian R; Poon, Emily; Alam, Murad

2018-01-01

Lighting is an important component of consistent, high-quality dermatologic photography. There are different types of lighting solutions available. To evaluate currently available lighting equipment and methods suitable for procedural dermatology. Overhead lighting, built-in camera flashes, external flash units, studio strobes, and light-emitting diode (LED) light panels were evaluated with regard to their utility for dermatologic surgeons. A set of ideal lighting characteristics was used to examine the capabilities and limitations of each type of lighting solution. Recommendations regarding lighting solutions and optimal usage configurations were made in terms of the context of the clinical environment and the purpose of the image. Overhead lighting may be a convenient option for general documentation. An on-camera lighting solution using a built-in camera flash or a camera-mounted external flash unit provides portability and consistent lighting with minimal training. An off-camera lighting solution with studio strobes, external flash units, or LED light panels provides versatility and even lighting with minimal shadows and glare. The selection of an optimal lighting solution is contingent on practical considerations and the purpose of the image.

46 CFR 167.65-5 - Flashing the rays of a searchlight or other blinding light.

Code of Federal Regulations, 2012 CFR

2012-10-01

... of a searchlight or other blinding light. Flashing the rays of a searchlight or other blinding light... 46 Shipping 7 2012-10-01 2012-10-01 false Flashing the rays of a searchlight or other blinding light. 167.65-5 Section 167.65-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED...

46 CFR 167.65-5 - Flashing the rays of a searchlight or other blinding light.

Code of Federal Regulations, 2011 CFR

2011-10-01

... of a searchlight or other blinding light. Flashing the rays of a searchlight or other blinding light... 46 Shipping 7 2011-10-01 2011-10-01 false Flashing the rays of a searchlight or other blinding light. 167.65-5 Section 167.65-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED...

46 CFR 167.65-5 - Flashing the rays of a searchlight or other blinding light.

Code of Federal Regulations, 2013 CFR

2013-10-01

... of a searchlight or other blinding light. Flashing the rays of a searchlight or other blinding light... 46 Shipping 7 2013-10-01 2013-10-01 false Flashing the rays of a searchlight or other blinding light. 167.65-5 Section 167.65-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED...

46 CFR 167.65-5 - Flashing the rays of a searchlight or other blinding light.

Code of Federal Regulations, 2014 CFR

2014-10-01

... of a searchlight or other blinding light. Flashing the rays of a searchlight or other blinding light... 46 Shipping 7 2014-10-01 2014-10-01 false Flashing the rays of a searchlight or other blinding light. 167.65-5 Section 167.65-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED...

46 CFR 167.65-5 - Flashing the rays of a searchlight or other blinding light.

Code of Federal Regulations, 2010 CFR

2010-10-01

... of a searchlight or other blinding light. Flashing the rays of a searchlight or other blinding light... 46 Shipping 7 2010-10-01 2010-10-01 false Flashing the rays of a searchlight or other blinding light. 167.65-5 Section 167.65-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED...

46 CFR 113.25-10 - Emergency red-flashing lights.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Emergency red-flashing lights. 113.25-10 Section 113.25... lights. (a) In a space described in § 113.25-9(a), where the general emergency alarm signal cannot be heard over the background noise, there must be a red-flashing light or rotating beacon, in addition to...

46 CFR 113.25-10 - Emergency red-flashing lights.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Emergency red-flashing lights. 113.25-10 Section 113.25... lights. (a) In a space described in § 113.25-9(a), where the general emergency alarm signal cannot be heard over the background noise, there must be a red-flashing light or rotating beacon, in addition to...

46 CFR 113.25-10 - Emergency red-flashing lights.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Emergency red-flashing lights. 113.25-10 Section 113.25... lights. (a) In a space described in § 113.25-9(a), where the general emergency alarm signal cannot be heard over the background noise, there must be a red-flashing light or rotating beacon, in addition to...

46 CFR 113.25-10 - Emergency red-flashing lights.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Emergency red-flashing lights. 113.25-10 Section 113.25... lights. (a) In a space described in § 113.25-9(a), where the general emergency alarm signal cannot be heard over the background noise, there must be a red-flashing light or rotating beacon, in addition to...

46 CFR 113.25-10 - Emergency red-flashing lights.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Emergency red-flashing lights. 113.25-10 Section 113.25... lights. (a) In a space described in § 113.25-9(a), where the general emergency alarm signal cannot be heard over the background noise, there must be a red-flashing light or rotating beacon, in addition to...

Increased Expression of CCN2 in the Red Flashing Light-Induced Myopia in Guinea Pigs

PubMed Central

Wang, Hong; Zhuang, Kang; Gao, Lei; Zhang, Linna; Yang, Hongling

2013-01-01

Visual environment plays an important role in the occurrence of myopia. We previously showed that the different flashing lights could result in distinct effects on the ocular growth and development of myopia. CCN2 has been reported to regulate various cellular functions and biological processes. However, whether CCN2 signaling was involved in the red flashing light-induced myopia still remains unknown. In the present study, we investigated the effects of the red flashing lights exposure on the refraction and axial length of the eyes in vivo and then evaluated their effects on the expression of CCN2 and TGF-β in sclera tissues. Our data showed that the eyes exposed to the red flashing light became more myopic with a significant increase of the axial length and decrease of the refraction. Both CCN2 and TGF-β, as well as p38 MAPK and PI3K, were highly expressed in the sclera tissues exposed to the red flashing light. Both CCN2 and TGF-β were found to have the same gene expression profile in vivo. In conclusion, our findings found that CCN2 signaling pathway plays an important role in the red flashing light-induced myopia in vivo. Moreover, our study establishes a useful animal model for experimental myopia research. PMID:23936844

Improving NIR snow pit stratigraphy observations by introducing a controlled NIR light source

NASA Astrophysics Data System (ADS)

Dean, J.; Marshall, H.; Rutter, N.; Karlson, A.

2013-12-01

Near-infrared (NIR) photography in a prepared snow pit measures mm-/grain-scale variations in snow structure, as reflectivity is strongly dependent on microstructure and grain size at the NIR wavelengths. We explore using a controlled NIR light source to maximize signal to noise ratio and provide uniform incident, diffuse light on the snow pit wall. NIR light fired from the flash is diffused across and reflected by an umbrella onto the snow pit; the lens filter transmits NIR light onto the spectrum-modified sensor of the DSLR camera. Lenses are designed to refract visible light properly, not NIR light, so there must be a correction applied for the subsequent NIR bright spot. To avoid interpolation and debayering algorithms automatically performed by programs like Adobe's Photoshop on the images, the raw data are analyzed directly in MATLAB. NIR image data show a doubling of the amount of light collected in the same time for flash over ambient lighting. Transitions across layer boundaries in the flash-lit image are detailed by higher camera intensity values than ambient-lit images. Curves plotted using median intensity at each depth, normalized to the average profile intensity, show a separation between flash- and ambient-lit images in the upper 10-15 cm; the ambient-lit image curve asymptotically approaches the level of the flash-lit image curve below 15cm. We hypothesize that the difference is caused by additional ambient light penetrating the upper 10-15 cm of the snowpack from above and transmitting through the wall of the snow pit. This indicates that combining NIR ambient and flash photography could be a powerful technique for studying penetration depth of radiation as a function of microstructure and grain size. The NIR flash images do not increase the relative contrast at layer boundaries; however, the flash more than doubles the amount of recorded light and controls layer noise as well as layer boundary transition noise.

Comparison of laser and intense pulsed light sintering (IPL) for inkjet-printed copper nanoparticle layers

PubMed Central

Niittynen, Juha; Sowade, Enrico; Kang, Hyunkyoo; Baumann, Reinhard R.; Mäntysalo, Matti

2015-01-01

In this contribution we discuss the sintering of an inkjet-printed copper nanoparticle ink based on electrical performance and microstructure analysis. Laser and intense pulsed light (IPL) sintering are employed in order to compare the different techniques and their feasibility for electronics manufacturing. A conductivity of more than 20% of that of bulk copper material has been obtained with both sintering methods. Laser and IPL sintering techniques are considered to be complementary techniques and are highly suitable in different application fields. PMID:25743631

Motorist actions at a crosswalk with an in-pavement flashing light system.

PubMed

Karkee, Ganesh J; Nambisan, Shashi S; Pulugurtha, Srinivas S

2010-12-01

An in-pavement flashing light system is used at crosswalks to alert motorists and pedestrians of possible conflicts and to influence their behavior to enhance safety. The relative behaviors of the drivers and the pedestrians affect safety. An evaluation of motorist behavior at a pedestrian crosswalk with an in-pavement flashing light system is presented in this manuscript. Field observations provide the basis to evaluate motorist behavior at a crosswalk with an in-pavement flashing light system. Outcomes of pedestrian and motorists actions were observed to quantify measures of effectiveness (MOEs) such as yielding behavior of motorists, vehicle speeds, and yielding distance from the crosswalk. A before-and-after study design was used. The before condition was prior to the activation of the in-pavement flashing light system and the after condition was after the activation of the in-pavement flashing light system. The study was conducted on a relatively low-volume roadway located in the Henderson, Nevada. The significance of the differences in the MOEs between the 2 study periods was evaluated using statistical analysis tools such as a one-tailed test for proportions and the Welch-Satterthwaite t-test. The results show that the installation of the in-pavement flashing light system increased the yielding behavior of motorists significantly (P < 0.001). The vehicular speeds decreased when pedestrians were waiting at the curb to cross and when they were crossing (P < 0.001). Motorists yielded to pedestrians on an average about 3 m (∼10 feet) upstream from the yield markings and the yielding distances were consistent in both directions. The in-pavement flashing light system is seen to be effective to improve motorists' yielding behavior and the speeds of vehicles were also observed to decrease in the presence of pedestrians.

Flashing light in microalgae biotechnology.

PubMed

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

2016-03-01

Flashing light can enhance photosynthesis and improve the quality and quantity of microalgal biomass, as it can increase the products of interest by magnitudes. Therefore, the integration of flashing light effect into microalgal cultivation systems should be considered. However, microalgae require a balanced mix of the light/dark cycle for higher growth rates, and respond to light intensity differently according to the pigments acquired or lost during the growth. This review highlights recently published results on flashing light effect on microalgae and its applications in biotechnology, as well as the recently developed bioreactors designed to fulfill this effect. It also discusses how this knowledge can be applied in selecting the optimal light frequencies and intensities with specific technical properties for increasing biomass production and/or the yield of the chemicals of interest by microalgae belonging to different genera. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of Internet websites about floaters and light flashes in patient education.

PubMed

Barbosa, Andréa Lima; Martins, Elisabeth Nogueira

2007-01-01

Flashes of light and floaters are most commonly caused by posterior vitreous separation but may be associated with sight-threatening disorders. Prevention of severe sequelae requires prompt dilated eye examination. Thus, information dissemination is crucial. This study aimed to evaluate the quality of information about floaters and light flashes available for patients on the Internet. Cross-sectional study. In July 2005 we evaluated information available on the Internet regarding floaters and light flashes, using two search engines (MetaCrawler and MSN) and three key terms ("floaters", "dark spots eye", and "light flashes eye"). The quality of each website was evaluated using a score system. The sites were classified as academic, organizational or commercial. Readability, general quality of the website (based on: ownership, purpose, authorship, author qualification, attribution, interactivity, and currency) and quality of the specific content (definition, causes, epidemiology, diagnosis, treatment, and prognosis) were analyzed. Of 145 websites evaluated, 49 were included. Four sites (8.2%) were academic, 9 (18.4%) organizational, and 36 (73.4%) commercial. In the majority of the sites (53.0%) information was poor and quality was not correlated with website classification. Information about floaters and light flashes available on the Internet is poor.

Fabrication of lanthanum-doped thorium dioxide by high-energy ball milling and spark plasma sintering

NASA Astrophysics Data System (ADS)

Scott, Spencer M.; Yao, Tiankai; Lu, Fengyuan; Xin, Guoqing; Zhu, Weiguang; Lian, Jie

2017-03-01

High-energy ball milling was used to synthesize Th1-xLaxO2-0.5x (x = 0.09, 0.23) solid solutions, as well as improve the sinterability of ThO2 powders. Dense La-doped ThO2 pellets with theoretical density above 94% were consolidated by spark plasma sintering at temperatures above 1400 °C for 20 min, and the densification behavior and the non-equilibrium effects on phase and structure were investigated. A lattice contraction of the SPS-densified pellets occurred with increasing ball milling duration, and a secondary phase with increased La-content was observed in La-doped pellets. A dependence on the La-content and sintering duration for the onset of localized phase segregation has been proposed. The effects of high-energy ball milling, La-content, and phase formation on the thermal diffusivity were also studied for La-doped ThO2 pellets by laser flash measurement. Increasing La-content and high energy ball milling time decreases thermal diffusivity; while the sintering peak temperature and holding time beyond 1600 °C dramatically altered the temperature dependence of the thermal diffusivity beyond 600 °C.

High coercivity, anisotropic, heavy rare earth-free Nd-Fe-B by Flash Spark Plasma Sintering.

PubMed

Castle, Elinor; Sheridan, Richard; Zhou, Wei; Grasso, Salvatore; Walton, Allan; Reece, Michael J

2017-09-11

In the drive to reduce the critical Heavy Rare Earth (HRE) content of magnets for green technologies, HRE-free Nd-Fe-B has become an attractive option. HRE is added to Nd-Fe-B to enhance the high temperature performance of the magnets. To produce similar high temperature properties without HRE, a crystallographically textured nanoscale grain structure is ideal; and this conventionally requires expensive "die upset" processing routes. Here, a Flash Spark Plasma Sintering (FSPS) process has been applied to a Dy-free Nd 30.0 Fe 61.8 Co 5.8 Ga 0.6 Al 0.1 B 0.9 melt spun powder (MQU-F, neo Magnequench). Rapid sinter-forging of a green compact to near theoretical density was achieved during the 10 s process, and therefore represents a quick and efficient means of producing die-upset Nd-Fe-B material. The microstructure of the FSPS samples was investigated by SEM and TEM imaging, and the observations were used to guide the optimisation of the process. The most optimal sample is compared directly to commercially die-upset forged (MQIII-F) material made from the same MQU-F powder. It is shown that the grain size of the FSPS material is halved in comparison to the MQIII-F material, leading to a 14% increase in coercivity (1438 kA m -1 ) and matched remanence (1.16 T) giving a BH max of 230 kJ m -3 .

33 CFR 118.110 - Daymarks and lateral lighting on bridges.

Code of Federal Regulations, 2012 CFR

2012-07-01

... through bridges with U.S. aids to navigation system lateral marks and lights installed on the... flashing, flashing, isophase or occulting red and green lights to mark the main channels. (b) If lateral system lights are required or authorized to mark the main navigation channels, fixed yellow lights shall...

33 CFR 118.110 - Daymarks and lateral lighting on bridges.

Code of Federal Regulations, 2013 CFR

2013-07-01

... through bridges with U.S. aids to navigation system lateral marks and lights installed on the... flashing, flashing, isophase or occulting red and green lights to mark the main channels. (b) If lateral system lights are required or authorized to mark the main navigation channels, fixed yellow lights shall...

33 CFR 118.110 - Daymarks and lateral lighting on bridges.

Code of Federal Regulations, 2014 CFR

2014-07-01

... through bridges with U.S. aids to navigation system lateral marks and lights installed on the... flashing, flashing, isophase or occulting red and green lights to mark the main channels. (b) If lateral system lights are required or authorized to mark the main navigation channels, fixed yellow lights shall...

14 CFR 31.65 - Position lights.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Position lights. 31.65 Section 31.65... STANDARDS: MANNED FREE BALLOONS Design Construction § 31.65 Position lights. (a) If position lights are installed, there must be one steady aviation white position light and one flashing aviation red (or flashing...

14 CFR 31.65 - Position lights.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Position lights. 31.65 Section 31.65... STANDARDS: MANNED FREE BALLOONS Design Construction § 31.65 Position lights. (a) If position lights are installed, there must be one steady aviation white position light and one flashing aviation red (or flashing...

14 CFR 31.65 - Position lights.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Position lights. 31.65 Section 31.65... STANDARDS: MANNED FREE BALLOONS Design Construction § 31.65 Position lights. (a) If position lights are installed, there must be one steady aviation white position light and one flashing aviation red (or flashing...

14 CFR 31.65 - Position lights.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Position lights. 31.65 Section 31.65... STANDARDS: MANNED FREE BALLOONS Design Construction § 31.65 Position lights. (a) If position lights are installed, there must be one steady aviation white position light and one flashing aviation red (or flashing...

14 CFR 31.65 - Position lights.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Position lights. 31.65 Section 31.65... STANDARDS: MANNED FREE BALLOONS Design Construction § 31.65 Position lights. (a) If position lights are installed, there must be one steady aviation white position light and one flashing aviation red (or flashing...

33 CFR 117.253 - Anacostia River.

Code of Federal Regulations, 2013 CFR

2013-07-01

... open position for vessel traffic. During open span movement, the channel traffic lights will flash red... traffic lights will flash red, and an audio voice-warning device will announce bridge movement during... will continue to flash red. (6) The owners of the bridge shall provide and keep in good legible...

33 CFR 117.253 - Anacostia River.

Code of Federal Regulations, 2014 CFR

2014-07-01

... open position for vessel traffic. During open span movement, the channel traffic lights will flash red... traffic lights will flash red, and an audio voice-warning device will announce bridge movement during... will continue to flash red. (6) The owners of the bridge shall provide and keep in good legible...

33 CFR 117.253 - Anacostia River.

Code of Federal Regulations, 2012 CFR

2012-07-01

... open position for vessel traffic. During open span movement, the channel traffic lights will flash red... traffic lights will flash red, and an audio voice-warning device will announce bridge movement during... will continue to flash red. (6) The owners of the bridge shall provide and keep in good legible...

Assessment of the broca-sulzer phenomenon via inter- and intra-modality matching procedures : studies of signal-light brightness.

DOT National Transportation Integrated Search

1968-10-01

Signal lights are presented to an observer as flashes with finite duration; thus, the effect of flash duration on the apparent brightness of the signal is important. The relation of effective signal brightness to flash duration and luminance finds ex...

Enhanced thermal diffusivity of copperbased composites using copper-RGO sheets

NASA Astrophysics Data System (ADS)

Kim, Sangwoo; Kwon, Hyouk-Chon; Lee, Dohyung; Lee, Hyo-Soo

2017-11-01

The synthesis of copper-reduced graphene oxide (RGO) sheets was investigated in order to control the agglutination of interfaces and develop a manufacturing process for copper-based composite materials based on spark plasma sintering. To this end, copper-GO (graphene oxide) composites were synthesized using a hydrothermal method, while the copper-reduced graphene oxide composites were made by hydrogen reduction. Graphene oxide-copper oxide was hydrothermally synthesized at 80 °C for 5 h, and then annealed at 800 °C for 5 h in argon and hydrazine rate 9:1 to obtain copper-RGO flakes. The morphology and structure of these copper-RGO sheets were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy. After vibratory mixing of the synthesized copper-RGO composites (0-2 wt%) with copper powder, they were sintered at 600 °C for 5 min under100 MPa of pressure by spark plasma sintering process. The thermal diffusivity of the resulting sintered composite was characterized by the laser flash method at 150 °C.

Extrafoveally applied flashing light affects contrast thresholds of achromatic and S-cone isolating, but not L-M cone modulated stimuli.

PubMed

Őze, A; Puszta, A; Buzás, P; Kóbor, P; Braunitzer, G; Nagy, A

2018-06-21

Flashing light stimulation is often used to investigate the visual system. However, the magnitude of the effect of this stimulus on the various subcortical pathways is not well investigated. The signals of conscious vision are conveyed by the magnocellular, parvocellular and koniocellular pathways. Parvocellular and koniocellular pathways (or more precisely, the L-M opponent and S-cone isolating channels) can be accessed by isoluminant red-green (L-M) and S-cone isolating stimuli, respectively. The main goal of the present study was to explore how costimulation with strong white extrafoveal light flashes alters the perception of stimuli specific to these pathways. Eleven healthy volunteers with negative neurological and ophthalmological history were enrolled for the study. Isoluminance of L-M and S-cone isolating sine-wave gratings was set individually, using the minimum motion procedure. The contrast thresholds for these stimuli as well as for achromatic gratings were determined by an adaptive staircase procedure where subjects had to indicate the orientation (horizontal, oblique or vertical) of the gratings. Thresholds were then determined again while a strong white peripheral light flash was presented 50 ms before each trial. Peripheral light flashes significantly (p < 0.05) increased the contrast thresholds of the achromatic and S-cone isolating stimuli. The threshold elevation was especially marked in case of the achromatic stimuli. However, the contrast threshold for the L-M stimuli was not significantly influenced by the light flashes. We conclude that extrafoveally applied light flashes influence predominantly the perception of achromatic stimuli. Copyright © 2018 Elsevier B.V. All rights reserved.

Special technical services for investigation of light flash phenomena

NASA Technical Reports Server (NTRS)

1973-01-01

Details are presented of an investigation aimed at an explanation of the phenomenon of light flashes observed by Apollo crew members. The various theories considered include: penetration of the eye by cosmic particles resulting in retinal stimulation; production of phosphenes or sensations of light through ionization or excitation; appearance of heavily ionized single tracks misinterpreted as light flashes; Cerenkov radiation; and direct excitation of neural tissue by penetrating cosmic rays. It is concluded that the latter two theories are the likeliest mechanisms for the development of a definitive explanation.

Excitation and desensitization of mouse rod photoreceptors in vivo following bright adapting light

PubMed Central

Kang Derwent, Jennifer J; Qtaishat, Nasser M; Pepperberg, David R

2002-01-01

Electroretinographic (ERG) methods were used to determine response properties of mouse rod photoreceptors in vivo following adapting illumination that produced a significant extent of rhodopsin bleaching. Bleaching levels prevailing at ∼10 min and ∼20 min after the adapting exposure were on average 14% and 9%, respectively, based on the analysis of visual cycle retinoids in the eye tissues. Recovery of the rod response to the adapting light was monitored by analysing the ERG a-wave response to a bright probe flash presented at varying times during dark adaptation. A paired-flash procedure, in which the probe flash was presented at defined times after a weak test flash of fixed strength, was used to determine sensitivity of the rod response to the test flash. Recovery of the response to the adapting light was 80% complete at 13.5 ± 3.0 min (mean ± s.d.; n = 7) after adapting light offset. The adapting light caused prolonged desensitization of the weak-flash response derived from paired-flash data. By comparison with results obtained in the absence of the adapting exposure, desensitization determined with a test-probe interval of 80 ms was ∼fourfold after 5 min of dark adaptation and ∼twofold after 20 min. The results indicate, for mouse rods in vivo, that the time scale for recovery of weak-flash sensitivity substantially exceeds that for the recovery of circulating current following significant rhodopsin bleaching. The lingering desensitization may reflect a reduced efficiency of signal transmission in the phototransduction cascade distinct from that due to residual excitation. PMID:12015430

49 CFR 221.14 - Marking devices.

Code of Federal Regulations, 2013 CFR

2013-10-01

... side of the horizontal center line as defined in terms of the 50 candela intensity points; (3) A color defined by the red-orange-amber color range; and (4) If a flashing light is used, a flash rate of not less... intensity of not less than 100 candela nor more than 1000 candela for flashing lights) as measured at the...

49 CFR 221.14 - Marking devices.

Code of Federal Regulations, 2012 CFR

2012-10-01

... side of the horizontal center line as defined in terms of the 50 candela intensity points; (3) A color defined by the red-orange-amber color range; and (4) If a flashing light is used, a flash rate of not less... intensity of not less than 100 candela nor more than 1000 candela for flashing lights) as measured at the...

49 CFR 221.14 - Marking devices.

Code of Federal Regulations, 2014 CFR

2014-10-01

... side of the horizontal center line as defined in terms of the 50 candela intensity points; (3) A color defined by the red-orange-amber color range; and (4) If a flashing light is used, a flash rate of not less... intensity of not less than 100 candela nor more than 1000 candela for flashing lights) as measured at the...

49 CFR 221.14 - Marking devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

... side of the horizontal center line as defined in terms of the 50 candela intensity points; (3) A color defined by the red-orange-amber color range; and (4) If a flashing light is used, a flash rate of not less... intensity of not less than 100 candela nor more than 1000 candela for flashing lights) as measured at the...

Determination of the Influence of Electric Fields upon the Densification of Ionic Ceramics

DTIC Science & Technology

2017-07-21

and assisting the development of new techniques to expose nanoparticles to non -contacting electrostatic fields at temperatures as high as 900...through TEM imaging, and assisting the development of new techniques to expose nanoparticles to non -contacting electrostatic fields at temperatures as...during flash sintering lead to non -homogeneous microstructures. We expect that therefore physical properties may be inhomogeneous depending local

Two-flash thresholds as a function of flash luminance and area.

DOT National Transportation Integrated Search

1968-09-01

The recent use of strobe lights in aviation suggests the possibility of using temporal patterns of short duration flashes as information-carrying signals. Under night flight conditions, two-flash thresholds were obtained using a two-interval, tempora...

Period and pulse duration with "strobe" lights

NASA Astrophysics Data System (ADS)

Birriel, Jennifer

2016-01-01

Strobe lights have traditionally been discussed in The Physics Teacher in the context of stop action strobe photography. During the Halloween season most department and hardware stores sell inexpensive, compact "strobe" lights (although these can be found online year round). These lights generally sell for under 10 and usually employ LED lights. Most such devices have a rotary switch to adjust the rate at which the LED bulbs flash. This rotary switch is not calibrated—i.e., it has no markings to indicate the rate, but in general the greater the rotation of the switch from the off position, the faster the rate of flashing. We show how these simple devices can be used with a light sensor to study both the frequency of flashing and the duration of the light pulse. We briefly discuss if these devices are truly strobe lights.

Maskless, reticle-free, lithography

DOEpatents

Ceglio, N.M.; Markle, D.A.

1997-11-25

A lithography system in which the mask or reticle, which usually carries the pattern to be printed onto a substrate, is replaced by a programmable array of binary (i.e. on/off) light valves or switches which can be programmed to replicate a portion of the pattern each time an illuminating light source is flashed. The pattern of light produced by the programmable array is imaged onto a lithographic substrate which is mounted on a scanning stage as is common in optical lithography. The stage motion and the pattern of light displayed by the programmable array are precisely synchronized with the flashing illumination system so that each flash accurately positions the image of the pattern on the substrate. This is achieved by advancing the pattern held in the programmable array by an amount which corresponds to the travel of the substrate stage each time the light source flashes. In this manner the image is built up of multiple flashes and an isolated defect in the array will only have a small effect on the printed pattern. The method includes projection lithographies using radiation other than optical or ultraviolet light. The programmable array of binary switches would be used to control extreme ultraviolet (EUV), x-ray, or electron, illumination systems, obviating the need for stable, defect free masks for projection EUV, x-ray, or electron, lithographies. 7 figs.

Maskless, reticle-free, lithography

DOEpatents

Ceglio, Natale M.; Markle, David A.

1997-11-25

A lithography system in which the mask or reticle, which usually carries the pattern to be printed onto a substrate, is replaced by a programmable array of binary (i.e. on/off) light valves or switches which can be programmed to replicate a portion of the pattern each time an illuminating light source is flashed. The pattern of light produced by the programmable array is imaged onto a lithographic substrate which is mounted on a scanning stage as is common in optical lithography. The stage motion and the pattern of light displayed by the programmable array are precisely synchronized with the flashing illumination system so that each flash accurately positions the image of the pattern on the substrate. This is achieved by advancing the pattern held in the programmable array by an amount which corresponds to the travel of the substrate stage each time the light source flashes. In this manner the image is built up of multiple flashes and an isolated defect in the array will only have a small effect on the printed pattern. The method includes projection lithographies using radiation other than optical or ultraviolet light. The programmable array of binary switches would be used to control extreme ultraviolet (EUV), x-ray, or electron, illumination systems, obviating the need for stable, defect free masks for projection EUV, x-ray, or electron, lithographies.

Effectiveness of an extended period of flashing lights and strategic signage to increase the salience of alcohol-gel dispensers for improving hand hygiene compliance.

PubMed

Rashidi, Babak; Li, Aimee; Patel, Rakesh; Harmsen, Irene E; Sabri, Elham; Kyeremanteng, Kwadwo; D'Egidio, Gianni

2016-07-01

Multiple factors affect compliance with hand hygiene, including conspicuity of alcohol-gel dispensers. Previous studies have shown that flashing lights increase hand hygiene compliance; however, the durability of this effect has not been studied. We affixed flashing lights to hand sanitizer dispensers for a total of 6 weeks. Regression analysis was used to compare compliance rates between the beginning and end of the intervention. Our secondary objective was to determine whether compliance rates in cold weather could be improved by adding a sign separated in time and space from the dispensers. Flashing lights improved hand hygiene compliance from 11.8% to 20.7%, and this effect was unchanged over the 6-week study period. Fully charged lights resulted in a greater compliance increase. A preemptive sign did not have a significant effect on hand hygiene rates nor did absolute temperatures. Flashing lights are a simple, inexpensive way of improving hand hygiene. Brighter lights appear to have a greater effect; however, this must be balanced with annoyance in specific settings. Temperature did not have a significant effect; however, this may be because the relationship does not fit a linear model. Other interventions, such as signs, may need to be tailored specifically to individual hospital environments. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Synthesis of zirconium oxynitride in air under DC electric fields

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

Morisaki, Nobuhiro; Tokunaga, Tomoharu; Sasaki, Katsuhiro

We synthesized zirconium oxynitride from yttria-stabilized zirconia (YSZ) in air by applying DC electric fields that produced a controlled electric current in the specimen. When YSZ was heated under an applied DC electric field, the electric current of the specimen steeply increased at a critical temperature, called a flash event, during flash sintering. By keeping the electric current of the specimen constant during the flash event and then holding the specimen at the critical temperature, YSZ was transformed into zirconium oxynitride under the optimal conditions of 50 V/cm, 500 mA, and 1000 °C. We confirmed that zirconium oxynitride formed using high-resolution transmission electronmore » microscopy, electron energy-loss spectroscopy, and energy-dispersive spectrometry. To convert oxides to nitrides, reducing conditions are necessary to form excess oxygen vacancies. Our technique produced the strong reducing conditions necessary to form nitrides from the oxides by delivering a controlled electric current to the specimen.« less

Effect of flash lamp annealing on electrical activation in boron-implanted polycrystalline Si thin films

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

Do, Woori; Jin, Won-Beom; Choi, Jungwan

2014-10-15

Highlights: • Intensified visible light irradiation was generated via a high-powered Xe arc lamp. • The disordered Si atomic structure absorbs the intensified visible light. • The rapid heating activates electrically boron-implanted Si thin films. • Flash lamp heating is applicable to low temperature polycrystalline Si thin films. - Abstract: Boron-implanted polycrystalline Si thin films on glass substrates were subjected to a short duration (1 ms) of intense visible light irradiation generated via a high-powered Xe arc lamp. The disordered Si atomic structure absorbs the intense visible light resulting from flash lamp annealing. The subsequent rapid heating results in themore » electrical activation of boron-implanted Si thin films, which is empirically observed using Hall measurements. The electrical activation is verified by the observed increase in the crystalline component of the Si structures resulting in higher transmittance. The feasibility of flash lamp annealing has also been demonstrated via a theoretical thermal prediction, indicating that the flash lamp annealing is applicable to low-temperature polycrystalline Si thin films.« less

Flash photolysis of rhodopsin in the cat retina

PubMed Central

1981-01-01

The bleaching of rhodopsin by short-duration flashes of a xenon discharge lamp was studied in vivo in the cat retina with the aid of a rapid, spectral-scan fundus reflectometer. Difference spectra recorded over a broad range of intensities showed that the bleaching efficacy of high-intensity flashes was less than that of longer duration, steady lights delivering the same amount of energy. Both the empirical results and those derived from a theoretical analysis of flash photolysis indicate that, under the conditions of these experiments, the upper limit of the flash bleaching of rhodopsin in cat is approximately 90%. Although the fact that a full bleach could not be attained is attributable to photoreversal, i.e., the photic regeneration of rhodopsin from its light-sensitive intermediates, the 90% limit is considerably higher than the 50% (or lower) value obtained under other experimental circumstances. Thus, it appears that the duration (approximately 1 ms) and spectral composition of the flash, coupled with the kinetic parameters of the thermal and photic reactions in the cat retina, reduce the light-induced regeneration of rhodopsin to approximately 10%. PMID:7252476

33 CFR 117.325 - St. Johns River.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., displaying flashing green lights to indicate that vessels may pass. (3) When a train approaches, large signs on both the upstream and downstream sides of the bridge flash “Bridge Coming Down,” the lights go to... track circuit is occupied. (4) After the train has cleared, the draw opens and the lights return to...

Welding of silver nanowire networks via flash white light and UV-C irradiation for highly conductive and reliable transparent electrodes

NASA Astrophysics Data System (ADS)

Chung, Wan-Ho; Kim, Sang-Ho; Kim, Hak-Sung

2016-08-01

In this work, silver nanowire inks with hydroxypropyl methylcellulose (HPMC) binders were coated on polyethylene terephthalate (PET) substrates and welded via flash white light and ultraviolet C (UV-C) irradiation to produce highly conductive transparent electrodes. The coated silver nanowire films were firmly welded and embedded into PET substrate successfully at room temperature and under ambient conditions using an in-house flash white light welding system and UV-C irradiation. The effects of light irradiation conditions (light energy, irradiation time, pulse duration, and pulse number) on the silver nanowire networks were studied and optimized. Bending fatigue tests were also conducted to characterize the reliability of the welded transparent conductive silver nanowire films. The surfaces of the welded silver nanowire films were analyzed via scanning electron microscopy (SEM), while the transmittance of the structures was measured using a spectrophotometer. From the results, a highly conductive and transparent silver nanowire film with excellent reliability could be achieved at room temperature under ambient conditions via the combined flash white light and UV-C irradiation welding process.

Welding of silver nanowire networks via flash white light and UV-C irradiation for highly conductive and reliable transparent electrodes

PubMed Central

Chung, Wan-Ho; Kim, Sang-Ho; Kim, Hak-Sung

2016-01-01

In this work, silver nanowire inks with hydroxypropyl methylcellulose (HPMC) binders were coated on polyethylene terephthalate (PET) substrates and welded via flash white light and ultraviolet C (UV-C) irradiation to produce highly conductive transparent electrodes. The coated silver nanowire films were firmly welded and embedded into PET substrate successfully at room temperature and under ambient conditions using an in-house flash white light welding system and UV-C irradiation. The effects of light irradiation conditions (light energy, irradiation time, pulse duration, and pulse number) on the silver nanowire networks were studied and optimized. Bending fatigue tests were also conducted to characterize the reliability of the welded transparent conductive silver nanowire films. The surfaces of the welded silver nanowire films were analyzed via scanning electron microscopy (SEM), while the transmittance of the structures was measured using a spectrophotometer. From the results, a highly conductive and transparent silver nanowire film with excellent reliability could be achieved at room temperature under ambient conditions via the combined flash white light and UV-C irradiation welding process. PMID:27553755

33 CFR 117.903 - Darby Creek.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., nine inches high to indicate the vertical clearance under the closed draw at all stages of the tide... change from flashing green to flashing red anytime the bridge is not in the full open position. (10) During downward span movement, the channel traffic lights will change from flashing green to flashing red...

33 CFR 117.903 - Darby Creek.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., nine inches high to indicate the vertical clearance under the closed draw at all stages of the tide... change from flashing green to flashing red anytime the bridge is not in the full open position. (10) During downward span movement, the channel traffic lights will change from flashing green to flashing red...

33 CFR 117.903 - Darby Creek.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., nine inches high to indicate the vertical clearance under the closed draw at all stages of the tide... change from flashing green to flashing red anytime the bridge is not in the full open position. (10) During downward span movement, the channel traffic lights will change from flashing green to flashing red...

Sintered bentonite ceramics for the immobilization of cesium- and strontium-bearing radioactive waste

NASA Astrophysics Data System (ADS)

Ortega, Luis Humberto

The Advanced Fuel Cycle Initiative (AFCI) is a Department of Energy (DOE) program, that has been investigating technologies to improve fuel cycle sustainability and proliferation resistance. One of the program's goals is to reduce the amount of radioactive waste requiring repository disposal. Cesium and strontium are two primary heat sources during the first 300 years of spent nuclear fuel's decay, specifically isotopes Cs-137 and Sr-90. Removal of these isotopes from spent nuclear fuel will reduce the activity of the bulk spent fuel, reducing the heat given off by the waste. Once the cesium and strontium are separated from the bulk of the spent nuclear fuel, the isotopes must be immobilized. This study is focused on a method to immobilize a cesium- and strontium-bearing radioactive liquid waste stream. While there are various schemes to remove these isotopes from spent fuel, this study has focused on a nitric acid based liquid waste. The waste liquid was mixed with the bentonite, dried then sintered. To be effective sintering temperatures from 1100 to 1200°C were required, and waste concentrations must be at least 25 wt%. The product is a leach resistant ceramic solid with the waste elements embedded within alumino-silicates and a silicon rich phase. The cesium is primarily incorporated into pollucite and the strontium into a monoclinic feldspar. The simulated waste was prepared from nitrate salts of stable ions. These ions were limited to cesium, strontium, barium and rubidium. Barium and rubidium will be co-extracted during separation due to similar chemical properties to cesium and strontium. The waste liquid was added to the bentonite clay incrementally with drying steps between each addition. The dry powder was pressed and then sintered at various temperatures. The maximum loading tested is 32 wt. percent waste, which refers to 13.9 wt. percent cesium, 12.2 wt. percent barium, 4.1 wt. percent strontium, and 2.0 wt. percent rubidium. Lower loadings of waste were also tested. The final solid product was a hard dense ceramic with a density that varied from 2.12 g/cm3 for a 19% waste loading with a 1200°C sintering temperature to 3.03 g/cm 3 with a 29% waste loading and sintered at 1100°C. Differential Scanning Calorimetry and Thermal Gravimetric Analysis (DSC-TGA) of the loaded bentonite displayed mass loss steps which were consistent with water losses in pure bentonite. Water losses were complete after dehydroxylation at ˜650°C. No mass losses were evident beyond the dehydroxylation. The ceramic melts at temperatures greater than 1300°C. Light flash analysis found heat capacities of the ceramic to be comparable to those of strontium and barium feldspars as well as pollucite. Thermal conductivity improved with higher sintering temperatures, attributed to lower porosity. Porosity was minimized in 1200°C sinterings. Ceramics with waste loadings less than 25 wt% displayed slump, the lowest waste loading, 15 wt% bloated at a 1200°C sintering. Waste loading above 25 wt% produced smooth uniform ceramics when sintered >1100°C. Sintered bentonite may provide a simple alternative to vitrification and other engineered radioactive waste-forms.

An upconverted photonic nonvolatile memory.

PubMed

Zhou, Ye; Han, Su-Ting; Chen, Xian; Wang, Feng; Tang, Yong-Bing; Roy, V A L

2014-08-21

Conventional flash memory devices are voltage driven and found to be unsafe for confidential data storage. To ensure the security of the stored data, there is a strong demand for developing novel nonvolatile memory technology for data encryption. Here we show a photonic flash memory device, based on upconversion nanocrystals, which is light driven with a particular narrow width of wavelength in addition to voltage bias. With the help of near-infrared light, we successfully manipulate the multilevel data storage of the flash memory device. These upconverted photonic flash memory devices exhibit high ON/OFF ratio, long retention time and excellent rewritable characteristics.

Light-Flash Wind-Direction Indicator

NASA Technical Reports Server (NTRS)

Zysko, Jan A.

1993-01-01

Proposed wind-direction indicator read easily by distant observers. Indicator emits bright flashes of light separated by interval of time proportional to angle between true north and direction from which wind blowing. Timing of flashes indicates direction of wind. Flashes, from high-intensity stroboscopic lights seen by viewers at distances up to 5 miles or more. Also seen more easily through rain and fog. Indicator self-contained, requiring no connections to other equipment. Power demand satisfied by battery or solar power or both. Set up quickly to provide local surface-wind data for aircraft pilots during landing or hovering, for safety officers establishing hazard zones and safety corridors during handling of toxic materials, for foresters and firefighters conducting controlled burns, and for real-time wind observations during any of variety of wind-sensitive operations.

Optimization of sintering conditions for cerium-doped yttrium aluminum garnet

NASA Astrophysics Data System (ADS)

Cranston, Robert Wesley McEachern

YAG:Ce phosphors have become widely used as blue/yellow light converters in camera projectors, white light emitting diodes (WLEDs) and general lighting applications. Many studies have been published on the production, characterization, and analysis of this optical ceramic but few have been done on determining optimal synthesis conditions. In this work, YAG:Ce phosphors were synthesized through solid state mixing and sintering. The synthesized powders and the highest quality commercially available powders were pressed and sintered to high densities and their photoluminescence (PL) intensity measured. The optimization process involved the sintering temperature, sintering time, annealing temperature and the level of Ce concentration. In addition to the PL intensity, samples were also characterized using particle size analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The PL data was compared with data produced from a YAG:Ce phosphor sample provided by Christie Digital. The peak intensities of the samples were converted to a relative percentage of this industry product. The highest value for the intensity of the commercial powder was measured for a Ce concentration of 0.3 mole% with a sintering temperature of 1540°C and a sintering dwell time of 7 hours. The optimal processing parameters for the in-house synthesized powder were slightly different from those of commercial powders. The optimal Ce concentration was 0.4 mole% Ce, sintering temperature was 1560°C and sintering dwell time was 10 hours. These optimal conditions produced a relative intensity of 94.20% and 95.28% for the in-house and commercial powders respectively. Polishing of these samples resulted in an increase of 5% in the PL intensity.

46 CFR 78.27-1 - Improper use prohibited.

Code of Federal Regulations, 2012 CFR

2012-10-01

... § 78.27-1 Improper use prohibited. (a) No person shall flash or cause to be flashed the rays of a search light or other blinding light onto the bridge or into the pilothouse of any vessel under way. (b...

46 CFR 78.27-1 - Improper use prohibited.

Code of Federal Regulations, 2010 CFR

2010-10-01

... § 78.27-1 Improper use prohibited. (a) No person shall flash or cause to be flashed the rays of a search light or other blinding light onto the bridge or into the pilothouse of any vessel under way. (b...

46 CFR 78.27-1 - Improper use prohibited.

Code of Federal Regulations, 2014 CFR

2014-10-01

... § 78.27-1 Improper use prohibited. (a) No person shall flash or cause to be flashed the rays of a search light or other blinding light onto the bridge or into the pilothouse of any vessel under way. (b...

46 CFR 78.27-1 - Improper use prohibited.

Code of Federal Regulations, 2011 CFR

2011-10-01

... § 78.27-1 Improper use prohibited. (a) No person shall flash or cause to be flashed the rays of a search light or other blinding light onto the bridge or into the pilothouse of any vessel under way. (b...

46 CFR 78.27-1 - Improper use prohibited.

Code of Federal Regulations, 2013 CFR

2013-10-01

... § 78.27-1 Improper use prohibited. (a) No person shall flash or cause to be flashed the rays of a search light or other blinding light onto the bridge or into the pilothouse of any vessel under way. (b...

Conspicuity of target lights: The influence of color

NASA Technical Reports Server (NTRS)

Connors, M. M.

1975-01-01

The conspicuity (or attention-getting qualities) were investigated of foveally-equated, colored lights, when seen against a star background. Subjects who were periodically engaged in a distracting cockpit task were required to search a large visual field and report the appearance of a target light as quickly as possible. Targets were red, yellow, white, green, and blue, and appeared either as steady or as flashing lights. Results indicate that red targets were missed more frequently and responded to more slowly than lights of other hues. Yellow targets were acquired more slowly than white, green, or blue targets; responses to white targets were significantly slower than responses to green or blue targets. In general, flashing lights were superior to steady lights, but this was not found for all hues. For red, the 2 Hz flash was superior to all other flash rates and to the steady light, none of which differed significantly from each other. Over all hues, conspicuity was found to peak at 2-3 Hz. Response time was found to be fastest, generally, for targets appearing at between 3 and 8 from the center of the visual field. However, this pattern was not repeated for every hue. Conspicuity response times suggest a complex relationship between hue and position in the visual field that is explained only partially by retinal sensitivity.

49 CFR 222.53 - What are the requirements for supplementary and alternative safety measures?

Code of Federal Regulations, 2010 CFR

2010-10-01

..., constitute SSMs or ASMs: Standard traffic control device arrangements such as reflectorized crossbucks, STOP signs, flashing lights, or flashing lights with gates that do not completely block travel over the line of railroad, or traffic signals. ...

49 CFR 222.53 - What are the requirements for supplementary and alternative safety measures?

Code of Federal Regulations, 2011 CFR

2011-10-01

..., constitute SSMs or ASMs: Standard traffic control device arrangements such as reflectorized crossbucks, STOP signs, flashing lights, or flashing lights with gates that do not completely block travel over the line of railroad, or traffic signals. ...

Do you see what I see? Optical morphology and visual capability of ‘disco’ clams (Ctenoides ales)

PubMed Central

Dubielzig, Richard R.; Schobert, Charles S.; Teixeira, Leandro B.; Li, Jingchun

2017-01-01

ABSTRACT The ‘disco’ clam Ctenoides ales (Finlay, 1927) is a marine bivalve that has a unique, vivid flashing display that is a result of light scattering by silica nanospheres and rapid mantle movement. The eyes of C. ales were examined to determine their visual capabilities and whether the clams can see the flashing of conspecifics. Similar to the congener C. scaber, C. ales exhibits an off-response (shadow reflex) and an on-response (light reflex). In field observations, a shadow caused a significant increase in flash rate from a mean of 3.9 Hz to 4.7 Hz (P=0.0016). In laboratory trials, a looming stimulus, which increased light intensity, caused a significant increase in flash rate from a median of 1.8 Hz to 2.2 Hz (P=0.0001). Morphological analysis of the eyes of C. ales revealed coarsely-packed photoreceptors lacking sophisticated structure, resulting in visual resolution that is likely too low to detect the flashing of conspecifics. As the eyes of C. ales are incapable of perceiving conspecific flashing, it is likely that their vision is instead used to detect predators. PMID:28396488

Homogeneity of Gd-based garnet transparent ceramic scintillators for gamma spectroscopy

NASA Astrophysics Data System (ADS)

Seeley, Z. M.; Cherepy, N. J.; Payne, S. A.

2013-09-01

Transparent polycrystalline ceramic scintillators based on the composition Gd1.49Y1.49Ce0.02Ga2.2Al2.8O12 are being developed for gamma spectroscopy detectors. Scintillator light yield and energy resolution depend on the details of various processing steps, including powder calcination, green body formation, and sintering atmosphere. We have found that gallium sublimation during vacuum sintering creates compositional gradients in the ceramic and can degrade the energy resolution. While sintering in oxygen produces ceramics with uniform composition and little afterglow, light yields are reduced, compared to vacuum sintering. By controlling the atmosphere during the various process steps, we were able to minimize the gallium sublimation, resulting in a more homogeneous composition and improved gamma spectroscopy performance.

Impact of absorptivity and wavelength on the optical properties of aggregates with sintering necks

NASA Astrophysics Data System (ADS)

Bao, Yujia; Huang, Yong; He, Beichen

2018-04-01

In this paper, we constructed sintered aggregates based on the particle superposition model and apply the ball-necking factor η to characterize the sintering degree. The impact of the absorptivity characterized by the complex refractive index m and the wavelength of the incident light λ on the optical properties of aggregates with different η were compared and investigated. The results indicate that for different m and λ, the light scattering characteristics exhibit regular changes in the values, the peak locations and the size trends. Further, the deviation of 1 - S22/S11 caused by various η is noteworthy and considerable so that it can be used as a probe sensor parameter in the detection of the sintered aggregates configuration.

An evaluation of UO2-CNT composites made by SPS as an accident tolerant nuclear fuel pellet and the feasibility of SPS as an economical fabrication process for the nuclear fuel cycle

NASA Astrophysics Data System (ADS)

Cartas, Andrew R.

The innovative and advanced purpose of this study is to understand and establish proper sintering procedures for Spark Plasma Sintering process in order to fabricate high density, high thermal conductivity UO2 -CNT pellets. Mixing quality and chemical reactions have been investigated by field emission scanning electron microscopy (FESEM), wavelength dispersive spectroscopy (WDS), and X-ray diffraction (XRD). The effect of various types of CNTs on the mixing and sintering quality of UO2-CNT pellets with SPS processing have been examined. The Archimedes Immersion Method, laser flash method, and FE-SEM will be used to investigate the density, thermal conductivity, grain size, pinning effects, and CNT dispersion of fabricated UO2-CNT pellets. Pre-fabricated CNT's were added to UO 2 powder and dispersed via sonication and/or ball milling and then made into composite nuclear pellets. An investigation of the economic impact of SPS on the nuclear fuel cycle for producing pure and composite UO2 fuels was conducted.

Correlation of individual cosmic ray nuclei with the observation of light flashes by Apollo astronauts. [nuclear emulsion detector design and operation

NASA Technical Reports Server (NTRS)

Pinsky, L. S.; Osborne, W. Z.; Bailey, J. V.

1975-01-01

A nuclear emulsion detector known as the Apollo Light Flash Moving Emulsion Detector (ALFMED) was designed: (1) to record tracks of primary cosmic rays; (2) to provide time-of-passage information via a relative plate translation technique; (3) to provide particle trajectory information; and (4) to fit into a masklike device that could be located about the head and eyes of an astronaut. An ALFMED device was worn by an astronaut observing light flashes for 60 minutes on each of the last two Apollo missions. During the Apollo 17 experiment seventeen separate flashes were reported by the observer. With one-third of the total plate area completely analyzed, two definite correlations have been found between Z greater than 8 cosmic ray nuclei traversing an eye and the reports of visual sensations.

Role of Cerenkov radiation in the eye-flashes observed by Apollo astronauts.

PubMed

McNulty, P J; Pease, V P; Bond, V P

1976-01-01

Visual phenomena in the form of colorless flashes of light were observed by astronauts in deep space when their eyes were closed and adapted to darkness. We describe in this paper laboratory experiments and calculations which indicate that many of these flashes are the result of visible light generated within the astronauts' eyeball in the form of Cerenkov radiation when a relativistic HZE particle traverses it. The sensitivity to Cerenkov radiation measured for three subjects exposed to pulses of pions and muons and the visual phenomena observed were found to be consistent with the reports of flashes observed at rates as high as 2 per minute on Apollo missions 11 through 17.

Transparent Lu 2 O 3 :Eu ceramics by sinter and HIP optimization

NASA Astrophysics Data System (ADS)

Seeley, Z. M.; Kuntz, J. D.; Cherepy, N. J.; Payne, S. A.

2011-09-01

Evolution of porosity and microstructure was observed during densification of lutetium oxide ceramics doped with europium (Lu 2O 3:Eu) fabricated via vacuum sintering and hot isostatic pressing (HIP'ing). Nano-scale starting powder was uniaxially pressed and sintered under high vacuum at temperatures between 1575 and 1850 °C to obtain densities ranging between 94% and 99%, respectively. Sintered compacts were then subjected to 200 MPa argon gas at 1850 °C to reach full density. Vacuum sintering above 1650 °C led to rapid grain growth prior to densification, rendering the pores immobile. Sintering between 1600 and 1650 °C resulted in closed porosity yet a fine grain size to allow the pores to remain mobile during the subsequent HIP'ing step, resulting in a fully-dense highly transparent ceramic without the need for subsequent air anneal. Light yield performance was measured and Lu 2O 3:Eu showed ˜4 times higher light yield than commercially used scintillating glass indicating that this material has the potential to improve the performance of high energy radiography devices.

Characterizing caged molecules through flash photolysis and transient absorption spectroscopy.

PubMed

Kao, Joseph P Y; Muralidharan, Sukumaran

2013-01-01

Caged molecules are photosensitive molecules with latent biological activity. Upon exposure to light, they are rapidly transformed into bioactive molecules such as neurotransmitters or second messengers. They are thus valuable tools for using light to manipulate biology with exceptional spatial and temporal resolution. Since the temporal performance of the caged molecule depends critically on the rate at which bioactive molecules are generated by light, it is important to characterize the kinetics of the photorelease process. This is accomplished by initiating the photoreaction with a very brief but intense pulse of light (i.e., flash photolysis) and monitoring the course of the ensuing reactions through various means, the most common of which is absorption spectroscopy. Practical guidelines for performing flash photolysis and transient absorption spectroscopy are described in this chapter.

50 CFR 600.504 - Facilitation of enforcement.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., 2182 kHz (SSB) radiotelephone, message block from an aircraft, flashing light or flag signals from the... “You should proceed at slow speed, a boat is coming to you”. (iii) “SQ3”, meaning “You should stop or... aircraft, flashing light signal, flaghoist, or loudhailer constitutes a violation of this subpart. (3) The...

Effectiveness of Flashing Lights and Flashing Lights with Gates in Reducing Accident Frequency at Public Rail-Highway Crossings, 1975-1978

DOT National Transportation Integrated Search

1980-04-01

The Highway Safety Acts of 1973 and 1976, and the Surface Transportation Assistance Act of 1978, provide funds to individual states to improve safety at public rail-highway crossings. The report was undertaken in support of a U.S. DOT effort to devel...

Flashes and Floaters.

PubMed

Sharma, Priya; Sridhar, Jayanth; Mehta, Sonia

2015-09-01

Flashes and floaters are common ocular complaints. Flashes refer to aberrations of light that are seen in a patient's field of gaze. The flashes can be of varying sizes, colors, frequency, and durations, depending on the cause. Floaters are another common visual phenomenon caused by particles or debris in the vitreous gel of the eye that cause shadows and thus visual changes, especially against bright backgrounds and in brightly lit environments. Flashes and floaters can occur individually or together. This article discusses common causes of flashes and floaters to help with the triaging and management of these patients. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of sintering temperature of Ce3+-doped Lu3Al5O12 phosphors on light emission and properties of crystal structure for white-light-emitting diodes

NASA Astrophysics Data System (ADS)

Koizumi, Hiroshi; Watabe, Junya; Sugiyama, Shin; Hirabayashi, Hideaki; Homma, Tetsuya

2018-06-01

The effect of the sintering temperature of Ce3+-doped Lu3Al5O12 (Ce-LuAG) phosphors on the emission and properties of the crystal structure was studied. A cathodoluminescence peak at 317 nm, which was assigned to lattice defects, was exhibited in addition to emission peaks at 508 and 540 nm for the Ce-LuAG phosphors. The intensities of the 317 nm emission peak for the phosphors with mean particle diameters of 5.0 and 10.0 µm formed at a low sintering temperature of 1430 °C were higher than those for the phosphors with mean particle diameters of 18.0 and 20.5 µm formed at a high sintering temperature of 1550 °C. In contrast, the electroluminescence spectra for fabricated white-light-emitting diodes (LEDs) using the phosphors revealed that the intensity of the peak at 540 nm was strong for the mean particle diameters of 18.0 and 20.5 µm. The intensity of the 540 nm peak, which is attributed to the 4f→5d transition of the Ce3+ activator, showed a dependence on the sintering temperature. The relationship between the optical properties and the lattice defects is discussed.

Light Flashes Observed by Astronauts on Apollo 11 through Apollo 17.

PubMed

Pinsky, L S; Osborne, W Z; Bailey, J V; Benson, R E; Thompson, L F

1974-03-08

The crew members on the last seven Apollo flights observed light flashes that are tentatively attributed to cosmic ray nuclei (atomic number >/= 6) penetrating the head and eyes of the observers. Analyses of the event rates for all missions has revealed an anomalously low rate for transearth coast observations with respect to translunar coast observations.

49 CFR 221.14 - Marking devices.

Code of Federal Regulations, 2010 CFR

2010-10-01

... side of the horizontal center line as defined in terms of the 50 candela intensity points; (3) A color defined by the red-orange-amber color range; and (4) If a flashing light is used, a flash rate of not less... classification light on the rear of the locomotive, provided it complies with paragraph (a) of this section; or...

Electronic Flash In Data Acquisition

NASA Astrophysics Data System (ADS)

Miller, C. E.

1982-02-01

Photographic acquisition of data often may be simplified, or the data quality improved upon by employing electronic flash sources with traditional equipment or techniques. The relatively short flash duration compared to movie camera shutters, or to the long integration time of video camera provides improved spatial resolution through blur reduction, particularly important as image movement becomes a significant fraction of film format dimension. Greater accuracy typically is achieved in velocity and acceleration determinations by using a stroboscopic light source rather than a movie camera frame-rate control as a time standard. Electrical efficiency often is an important advantage of electronic flash sources since almost any necessary light level for exposure may be produced, yet the source typically is "off" most of the time. Various synchronization techniques greatly expand the precise control of exposure. Biomechanical and sports equipment studies may involve velocities up to 200 feet-per-second, and often will have associated very rapid actions of interest. The need for brief exposures increases H.s one "ZOOMS in on the action." In golf, for example, the swing may be examined using 100 microsecond (Us) flashes at rates of 60 or 120 flashes-per-second (FPS). Accurate determination of linear and rotational velocity of the ball requires 10 Us flashes at 500-1,000 FPS, while sub-Us flashes at 20,000-50,000 FPS are required to resolve the interaction of the ball and the club, head. Some seldom. used techniques involving streak photography are described, with enhanced results obtained by combining strobe with the usual continuous light source. The combination of strobe and a fast electro-mechanical shutter is considered for Us photography under daylight conditions.

Corrosion and protection of NdFeB type magnets

NASA Astrophysics Data System (ADS)

Cavalloti, P.; Bozzini, B.; Cecchini, R.; Bava, G. F.; Davies, H. A.; Hoggarth, C.

1992-02-01

A general mechanism for the corrosion behaviour of NdFeB magnets is presented, related to the magnet heterogeneity with the presence of different phases. Cathodic control is outlined. An electrochemical method to assess the corrosion resistance of magnets, with and without coatings, is proposed; it is based on the study of the transient voltage at the magnet surface after a second cathodic current pulse in a suitable aggressive solution and its dependence on the amount of cathodic current circulating. Suitable pretreatments have been tried and interesting results obtained with passivation pretreatments, giving phosphorous Nd at grain boundaries. Coatings if sintered and plastic magnets have been tried using several methods. Good results are obtained with Zn-Co layers on sintered magnets and a sol-gel glass on powders for plastic magnets. Improved ACS (Autocatalytic Chemical Deposition) Ni=P coatings have been realized, with an alkaline brass flash plating to start ACD deposition.

FLASH fly-by-light flight control demonstration results overview

NASA Astrophysics Data System (ADS)

Halski, Don J.

1996-10-01

The Fly-By-Light Advanced Systems Hardware (FLASH) program developed Fly-By-Light (FBL) and Power-By-Wire (PBW) technologies for military and commercial aircraft. FLASH consists of three tasks. Task 1 developed the fiber optic cable, connectors, testers and installation and maintenance procedures. Task 3 developed advanced smart, rotary thin wing and electro-hydrostatic (EHA) actuators. Task 2, which is the subject of this paper,l focused on integration of fiber optic sensors and data buses with cable plant components from Task 1 and actuators from Task 3 into centralized and distributed flight control systems. Both open loop and piloted hardware-in-the-loop demonstrations were conducted with centralized and distributed flight control architectures incorporating the AS-1773A optical bus, active hand controllers, optical sensors, optimal flight control laws in high speed 32-bit processors, and neural networks for EHA monitoring and fault diagnosis. This paper overviews the systems level testing conducted under the FLASH Flight Control task. Preliminary results are summarized. Companion papers provide additional information.

The absence of attenuating effect of red light exposure on pre-existing melanopsin-driven post-illumination pupil response.

PubMed

Lei, Shaobo; Goltz, Herbert C; Sklar, Jaime C; Wong, Agnes M F

2016-07-01

It has been proposed that after activation by blue light, activated melanopsin is converted back to its resting state by long wavelength red light exposure, a putative mechanism of melanopsin chromophore recovery in vivo. We tested this hypothesis by investigating whether red light attenuates the ongoing post-illumination pupil response (PIPR) induced by melanopsin-activating blue light. Pupillary light responses were tested using "Blue+Red" double flashes and "Blue Only" single flash stimuli in 10 visually normal subjects. For "Blue+Red" conditions, PIPR was induced with an intense blue flash, followed by experimental red light exposure of variable intensity and duration (Experiment 1) immediately or 9s after the offset of the blue flash (Experiment 2). For "Blue Only" conditions, only the PIPR-inducing blue stimuli were presented (reference condition). PIPR was defined as the mean pupil size from 10 to 30s (Experiment 1) and from 25 to 60s (Experiment 2) after the offset of blue light stimuli. The results showed that PIPR from "Blue+Red" conditions did not differ significantly from those of "Blue Only" conditions (p=0.55) in Experiment 1. The two stimulation conditions also did not differ in Experiment 2 (p=0.38). We therefore conclude that red light exposure does not alter the time course of PIPR induced by blue light. This finding does not support the hypothesis that long wavelength red light reverses activated melanopsin; rather it lends support to the hypothesis that the wavelengths of stimuli driving both the forward and backward reactions of melanopsin may be similar. Copyright © 2016. Published by Elsevier Ltd.

Car driver behavior at flashing light railroad grade crossings.

PubMed

Tenkink, E; Van der Horst, R

1990-06-01

The behavior of car drivers at two Dutch railroad grade crossings with automatic flashing warning lights was analyzed. Car drivers were videotaped while approaching either the red flashing lights or the white flashing "safe"-signal. Approach speeds, positions, and time intervals were semiautomatically measured from videos of more than 900 drivers: 660 while confronted with the red lights and 272 while passing the white light. Of the latter group, head movements during the approach to the crossing were also registered. Red light compliance was relatively good, as no driver was observed to cross later than 6 seconds after the onset of the red lights, despite train-arrival times of well over 60 seconds. The level of red light compliance was further quantified in terms of both the deceleration and time-to-stopping-line as accepted by drivers. From a comparison with earlier research on red light compliance at signalized road intersections it appeared that red light compliance was better at railroad crossings than at road crossings. It is concluded that faulty red light compliance is not a major cause for car-train accidents and that emphasis should be placed on the ability of the present device to attract attention and to signal unambiguously. The high degree of compliance also causes unexpected driver actions, such as emergency braking and hesitations. A yellow phase may reduce these problems. Some drivers tended to proceed immediately after a train had cleared the road instead of waiting for the end of the red signal (typically some 3 to 5 seconds after the train had passed). This tendency might reveal a major cause of dramatic errors when a second train is approaching. Immediate extinction of the red signal is suggested, or even better, a separate signal to announce the arrival of the second train. Behavior during the white signal phase also showed indications of uncertainty. In some 10% of cases drivers tended to decelerate more strongly than necessary and to make extra head movements. It is recommended that the present white flashing signal be reconsidered.

Perfect Lighting for Facial Photography in Aesthetic Surgery: Ring Light.

PubMed

Dölen, Utku Can; Çınar, Selçuk

2016-04-01

Photography is indispensable for plastic surgery. On-camera flashes can result in bleached out detail and colour. This is why most of the plastic surgery clinics prefer studio lighting similar to professional photographers'. In this article, we want to share a simple alternative to studio lighting that does not need extra space: Ring light. We took five different photographs of the same person with five different camera and lighting settings: Smartphone and ring light; point and shoot camera and on-camera flash; point and shoot camera and studio lighting; digital single-lens reflex (DLSR) camera and studio lighting; DSLR and ring light. Then, those photographs were assessed objectively with an online survey of five questions answered by three distinct populations: plastic surgeons (n: 28), professional portrait photographers (n: 24) and patients (n: 22) who had facial aesthetic procedures. Compared to the on-camera flash, studio lighting better showed the wrinkles of the subject. The ring light facilitated the perception of the wrinkles by providing homogenous soft light in a circular shape rather than bursting flashes. The combination of a DSLR camera and ring light gave the oldest looking subject according to 64 % of responders. The DSLR camera and the studio lighting demonstrated the youngest looking subject according to 70 % of the responders. The majority of the responders (78 %) chose the combination of DSLR camera and ring light that exhibited the wrinkles the most. We suggest using a ring light to obtain well-lit photographs without loss of detail, with any type of cameras. However, smartphones must be avoided if standard pictures are desired. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Flash Bulletin: Fireflies

ERIC Educational Resources Information Center

Brown, Debbie

1984-01-01

Explains the flashes of light emitted by fireflies as competition, species-specific code, species identification and mating behavior and ecology. Suggests activities to conduct to study the insects and their behavior. (ERB)

BRAIN CHOLINESTERASE INHIBITION PRODUCED BY PROPOXUR AND DEPRESSION OF THE PHOTIC AFTER DISCHARGE OF FLASH EVOKED POTENTIALS IN LONG EVANS RATS.

EPA Science Inventory

Propoxur is a widely used N-methyl carbamate pesticide that acts by inhibiting cholinesterases (ChE), which may lead to cholinergic toxicity. Flash evoked potentials (FEPs) are a neurophysiological response following stimulation of the visual system with flashes of light. They ar...

Determining the coordinates of lamps in an illumination dome

NASA Astrophysics Data System (ADS)

MacDonald, Lindsay W.; Ahmadabadian, Ali H.; Robson, Stuart

2015-05-01

The UCL Dome consists of an acrylic hemisphere of nominal diameter 1030 mm, fitted with 64 flash lights, arranged in three tiers of 16, one tier of 12, and one tier of 4 lights at approximately equal intervals. A Nikon D200 digital camera is mounted on a rigid steel frame at the `north pole' of the dome pointing vertically downwards with its optical axis normal to the horizontal baseboard in the `equatorial' plane. It is used to capture sets of images in pixel register for visualisation and surface reconstruction. Three techniques were employed for the geometric calibration of flash light positions in the dome: (1) the shadow cast by a vertical pin onto graph paper; (2) multi-image photogrammetry with retro-reflective targets; and (3) multi-image photogrammetry using the flash lights themselves as targets. The precision of the coordinates obtained by the three techniques was analysed, and it was found that although photogrammetric methods could locate individual targets to an accuracy of 20 μm, the uncertainty of locating the centroids of the flash lights was approximately 1.5 mm. This result was considered satisfactory for the purposes of using the dome for photometric imaging, and in particular for the visualisation of object surfaces by the polynomial texture mapping (PTM) technique.

Interactions of numerical and temporal stimulus characteristics on the control of response location by brief flashes of light.

PubMed

Fetterman, J Gregor; Killeen, P Richard

2011-09-01

Pigeons pecked on three keys, responses to one of which could be reinforced after 3 flashes of the houselight, to a second key after 6, and to a third key after 12. The flashes were arranged according to variable-interval schedules. Response allocation among the keys was a function of the number of flashes. When flashes were omitted, transitions occurred very late. Increasing flash duration produced a leftward shift in the transitions along a number axis. Increasing reinforcement probability produced a leftward shift, and decreasing reinforcement probability produced a rightward shift. Intermixing different flash rates within sessions separated allocations: Faster flash rates shifted the functions sooner in real time, but later in terms of flash count, and conversely for slower flash rates. A model of control by fading memories of number and time was proposed.

Direct stimulation of the retina by the method of virtual-quanta for heavy cosmic-ray nuclei

NASA Technical Reports Server (NTRS)

Mcnulty, P. J.; Madey, R.

1972-01-01

The contribution to the frequency of visual sensations induced in the dark-adapted eye by the virtual photon field was calculated, this field is associated with the heavy nuclei that exist in space beyond the geomagnetic field. In order to determine the probability that the virtual photon field induces a light flash, only the portion of the virtual photon spectrum that corresponds to the known frequency dependence of the sensitivity of human rods to visible light was utilized. The results can be expressed as a curve of the mean frequency of light flashes induced by the absorption of at least R virtual photons versus the threshold number R. The contribution to the light flash frequency from the virtual photon field of heavy cosmic ray nuclei is smaller than that from Cerenkov photons. The flux and energy spectra of galactic cosmic ray nuclei helium to iron were used.

High-intensity pulse light sintering of silver nanowire transparent films on polymer substrates: the effect of the thermal properties of substrates on the performance of silver films.

PubMed

Jiu, Jinting; Sugahara, Tohru; Nogi, Masaya; Araki, Teppei; Suganuma, Katsuaki; Uchida, Hiroshi; Shinozaki, Kenji

2013-12-07

Silver nanowire (AgNW) films with a random mesh structure have attracted considerable attention as high-performance flexible transparent electrodes that can replace the expensive and brittle ITO-sputtered films widely used in displays, touch screens, and solar cells. Methods such as heating, pressure treatment, and light treatment are usually used to obtain an optically transparent and electrically conductive film comparable to those of commercial ITO. However, the adhesion between the AgNW film and the substrate is so weak that other overcoatings or extra treatments are necessary. Here, a high-intensity pulsed light (HIPL) sintering technique was developed to rapidly and simply sinter the AgNW film and thus achieve strong adhesion and even high conductivity on these flexible polymer substrates which will be widely applied to the printing of electronic devices. The conductivity of the AgNW film closely depended on the thermal performance of substrates, and the adhesion was determined by the soft state of the substrate surface originating from the glass transition or melting of substrates with light intensity. The rapid sintering technique can be popularized to fabricate new devices on these polymer substrates by considering the thermal properties of the substrate to improve the performance of devices.

Development of High-Strength Nanostructured Magnesium Alloys for Light-Weight Weapon Systems and Vehicles

DTIC Science & Technology

2014-01-13

strength nanocrystalline Mg-alloys via cryomilling and spark - plasma - sintering , 2) demonstrate the unveil evidence of nanotwins in nanocrystalline...Christopher Melnyk, Wei H. Kao, Jenn-Ming Yang. Cryomilling and spark plasma sintering of nanocrystalline magnesium-based alloy, Journal of Materials...accomplished several important milestones: 1) manufacture of high strength nanocrystalline Mg-alloys via cryomilling and spark plasma sintering (SPS

PS II model based analysis of transient fluorescence yield measured on whole leaves of Arabidopsis thaliana after excitation with light flashes of different energies.

PubMed

Belyaeva, N E; Schmitt, F-J; Paschenko, V Z; Riznichenko, G Yu; Rubin, A B; Renger, G

2011-02-01

Our recently presented PS II model (Belyaeva et al., 2008) was improved in order to permit a consistent simulation of Single Flash Induced Transient Fluorescence Yield (SFITFY) traces that were earlier measured by Steffen et al. (2005) on whole leaves of Arabidopsis (A.) thaliana at four different energies of the actinic flash. As the essential modification, the shape of the actinic flash was explicitly taken into account assuming that an exponentially decaying rate simulates the time dependent excitation of PS II by the 10 ns actinic flash. The maximum amplitude of this excitation exceeds that of the measuring light by 9 orders of magnitude. A very good fit of the SFITFY data was achieved in the time domain from 100 ns to 10s for all actinic flash energies (the maximum energy of 7.5 × 10¹⁶ photons/(cm²flash) is set to 100%, the relative energies of weaker actinic flashes were of ∼8%, 4%, ∼1%). Our model allows the calculation and visualization of the transient PS II redox state populations ranging from the dark adapted state, via excitation energy and electron transfer steps induced by pulse excitation, followed by final relaxation into the stationary state eventually attained under the measuring light. It turned out that the rate constants of electron transfer steps are invariant to intensity of the actinic laser flash. In marked contrast, an increase of the actinic flash energy by more than two orders of magnitude from 5.4×10¹⁴ photons/(cm²flash) to 7.5×10¹⁶ photons/(cm²flash), leads to an increase of the extent of fluorescence quenching due to carotenoid triplet (³Car) formation by a factor of 14 and of the recombination reaction between reduced primary pheophytin (Phe(-)) and P680(+) by a factor of 3 while the heat dissipation in the antenna complex remains virtually constant. The modified PS II model offers new opportunities to compare electron transfer and dissipative parameters for different species (e.g. for the green algae and the higher plant) under varying illumination conditions. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

[Effect of compaction pressure on the properties of dental machinable zirconia ceramic].

PubMed

Huang, Hui; Wei, Bin; Zhang, Fu-qiang; Sun, Jing; Gao, Lian

2010-10-01

To investigate the effect of compaction pressure on the linear shrinkage, sintering property and machinability of the dental zirconia ceramic. The nano-size zirconia powder was compacted at different isostatic pressure and sintered at different temperature. The linear shrinkage of sintered body was measured and the relative density was tested using the Archimedes method. The cylindrical surface of pre-sintering blanks was traversed using a hard metal tool. Surface and edge quality were checked visually using light stereo microscopy. The sintering behaviour depended on the compaction pressure. Increasing compaction pressure led to higher sintering rate and lower sintering temperature. Increasing compaction pressure also led to decreasing linear shrinkage of the sintered bodies, from 24.54% of 50 MPa to 20.9% of 400 MPa. Compaction pressure showed only a weak influence on machinability of zirconia blanks, but the higher compaction pressure resulted in the poor surface quality. The better sintering property and machinability of dental zirconia ceramic is found for 200-300 MPa compaction pressure.

Experimental tests of light-pollution impacts on nocturnal insect courtship and dispersal.

PubMed

Firebaugh, Ariel; Haynes, Kyle J

2016-12-01

Though a number of effects of artificial light pollution on behavior and physiology have been described, there is little understanding of their consequences for the growth and distribution of populations. Here, we document impacts of light pollution on aspects of firefly population ecology and underlying mating behaviors. Many firefly species have a unique communication system whereby bioluminescent flashes are used in courtship displays to find and attract mates. We performed a series of manipulative field experiments in which we quantified the effects of adding artificial nighttime lighting on abundances and total flashing activity of fireflies, courtship behaviors and mating between tethered females and free-flying males, and dispersal distances of marked individuals. We show that light pollution reduces flashing activities in a dark-active firefly species (Photuris versicolor) by 69.69 % and courtship behavior and mating success in a twilight-active species (Photinus pyralis). Though courtship behavior and mating success of Photinus pyralis was reduced by light pollution, we found no effects of light pollution on male dispersal in this species. Our findings suggest that light pollution is likely to adversely impact firefly populations, and contribute to wider discussions about the ecological consequences of sensory pollution.

The impact of red light running camera flashes on younger and older drivers' attention and oculomotor control.

PubMed

Wright, Timothy J; Vitale, Thomas; Boot, Walter R; Charness, Neil

2015-12-01

Recent empirical evidence has suggested that the flashes associated with red light running cameras (RLRCs) distract younger drivers, pulling attention away from the roadway and delaying processing of safety-relevant events. Considering the perceptual and attentional declines that occur with age, older drivers may be especially susceptible to the distracting effects of RLRC flashes, particularly in situations in which the flash is more salient (a bright flash at night compared with the day). The current study examined how age and situational factors potentially influence attention capture by RLRC flashes using covert (cuing effects) and overt (eye movement) indices of capture. We manipulated the salience of the flash by varying its luminance and contrast with respect to the background of the driving scene (either day or night scenes). Results of 2 experiments suggest that simulated RLRC flashes capture observers' attention, but, surprisingly, no age differences in capture were observed. However, an analysis examining early and late eye movements revealed that older adults may have been strategically delaying their eye movements in order to avoid capture. Additionally, older adults took longer to disengage attention following capture, suggesting at least 1 age-related disadvantage in capture situations. Findings have theoretical implications for understanding age differences in attention capture, especially with respect to capture in real-world scenes, and inform future work that should examine how the distracting effects of RLRC flashes influence driver behavior. (c) 2015 APA, all rights reserved).

The Impact of Red Light Running Camera Flashes on Younger and Older Drivers' Attention and Oculomotor Control

PubMed Central

Wright, Timothy J.; Vitale, Thomas; Boot, Walter R; Charness, Neil

2015-01-01

Recent empirical evidence suggests that the flashes associated with red light running cameras (RLRCs) distract younger drivers, pulling attention away from the roadway and delaying processing of safety-relevant events. Considering the perceptual and attentional declines that occur with age, older drivers may be especially susceptible to the distracting effects of RLRC flashes, particularly in situations in which the flash is more salient (a bright flash at night compared to the day). The current study examined how age and situational factors potentially influence attention capture by RLRC flashes using covert (cuing effects) and overt (eye movement) indices of capture. We manipulated the salience of the flash by varying its luminance and contrast with respect to the background of the driving scene (either day or night scenes). Results of two experiments suggest that simulated RLRC flashes capture observers' attention, but, surprisingly, no age differences in capture were observed. However, an analysis examining early and late eye movements revealed that older adults may have been strategically delaying their eye movements in order to avoid capture. Additionally, older adults took longer to disengage attention following capture, suggesting at least one age-related disadvantage in capture situations. Findings have theoretical implications for understanding age differences in attention capture, especially with respect to capture in real-world scenes, and inform future work that should examine how the distracting effects of RLRC flashes influence driver behavior. PMID:26479014

Defining the unknowns of sonoluminescence

NASA Astrophysics Data System (ADS)

Barber, Bradley P.; Hiller, Robert A.; Löfstedt, Ritva; Putterman, Seth J.; Weninger, Keith R.

1997-03-01

As the intensity of a standing sound wave is increased the pulsations of a bubble of gas trapped at a velocity node attain sufficient amplitude so as to emit picosecond flashes of light with a broadband spectrum that increases into the ultraviolet. The acoustic resonator can be tuned so that the flashes of light occur with a clocklike regularity: one flash for each cycle of sound with a jitter in the time between flashes that is also measured in picoseconds. This phenomenon (sonoluminescence or “SL”) is remarkable because it is the only means of generating picosecond flashes of light that does not use a laser and the input acoustic energy density must be concentrated by twelve orders of magnitude in order to produce light. Light scattering measurements indicate that the bubble wall is collapsing at more than 4 times the ambient speed of sound in the gas just prior to the light emitting moment when the gas has been compressed to a density determined by its van der Waals hard core. Experiments indicate that the collapse is remarkably spherical, water is the best fluid for SL, some noble gas is essential for stable SL, and that the light intensity increases as the ambient temperature is lowered. In the extremely stable experimental configuration consisting of an air bubble in water, measurements indicate that the bubble chooses an ambient radius that is not explained by mass diffusion. Experiments have not yet been able to map out the complete spectrum because above 6 eV it is obscured by the cutoff imposed by water, and furthermore experiments have only determined an upper bound on the flash widths. In addition to the above puzzles, the theory for the light emitting mechanism is still open. The scenario of a supersonic bubble collapse launching an imploding shock wave which ionizes the bubble contents so as to cause it to emit Bremsstrahlung radiation is the best candidate theory but it has not been shown how to extract from it the richness of this phenomenon. Most exciting is the issue of whether SL is a classical effect or whether Planck's constant should be invoked to explain how energy which enters a medium at the macroscopic scale holds together and focuses so as to be emitted at the microscopic scale.

Role of nuclear stars in the light flashes observed on Skylab 4.

PubMed

McNulty, P J; Filz, R C; Rothwell, P L

1977-01-01

The astronauts on Skylab 4 observed bursts of intense visual light-flash activity when their spacecraft passed through the portion of the earth's inner trapped radiation belt known as the South Atlantic Anomaly (SAA). Two experimental sessions were carried out on board Skylab 4 under the auspices of Pinsky et al. who compare the flash rates with the measured flux of Z > or = 1 particles that would pass through the astronaut's eyes. They concluded that the flash rates, which became as great as 20/min, were anomalously high. We explored a number of alternative explanations for the anomalous flash rates that would be consistent with the accepted SAA flux values and the laboratory data on particle induced visual sensations and found that when one includes the effect of nuclear interactions in and near the retina which result in star formation (the emission of slow protons, neutrons and alpha particles form the nucleus in an evaporation-like process) the apparent anomaly is removed.

Visible-light-responsive photocatalyst prepared by sintering a TiO2/Cu plate

NASA Astrophysics Data System (ADS)

Kogoshi, Sumio; Araki, Syota; Yazawa, Syota; Nakano, Takuma; Takeuchi, Tomohiko; Katayama, Noboru; Kudo, Yusuke; Nakanishi, Tetsuya

2014-09-01

A visible-light-responsive photocatalyst has been prepared simply by sintering a TiO2-coated Cu plate. The new photocatalyst was able to reduce the concentration of formaldehyde by 8-12% at ca. 296 K with an air flow rate of ca. 0.5 L/min (ca. 1 ppm formaldehyde included), a photocatalyst cross section of 50 × 100 mm2, ca. 50% humidity, and light intensity of 30 W/m2 (white LED light). The reduction rate was approximately two times higher than that for N-doped TiO2 (TiO2-xNx) under almost the same test conditions.

A novel airlift photobioreactor with baffles for improved light utilization through the flashing light effect.

PubMed

Degen, J; Uebele, A; Retze, A; Schmid-Staiger, U; Trösch, W

2001-12-28

A newly developed flat panel airlift photobioreactor with a defined circulation path was tested for microalgal culture. The bioreactor exposed the cells to intermittent light to improve the efficiency of light utilization through the flashing-light effect. During batch cultures in the new photobioreactor, the biomass productivity of Chlorella vulgaris was 1.7 times greater than in a randomly mixed bubble column of identical dimension. A reduction in light path from 30 to 15 mm increased the biomass productivity by 2.5-fold. A maximum dry biomass productivity of 0.11 g l(-1) h(-1) was obtained at an artificial illumination of 980 mu E m(-2) s(-1).

Flashes of light-radiation therapy to the brain.

PubMed

Blumenthal, Deborah T; Corn, Benjamin W; Shtraus, Natan

2015-08-01

We present a series of three patients who received therapeutic external beam radiation to the brain and experienced a phenomenon of the sensation of flashes of bright or blue light, simultaneous with radiation delivery. We relate this benign phenomenon to low-dose exposure to the eye fields and postulate that the occurrence is underreported in this treated population. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Effectiveness of traffic light vs. boom barrier controls at road-rail level crossings: a simulator study.

PubMed

Rudin-Brown, Christina M; Lenné, Michael G; Edquist, Jessica; Navarro, Jordan

2012-03-01

Although collisions at level crossings are relatively uncommon occurrences, the potential severity of their consequences make them a top priority among safety authorities. Twenty-five fully-licensed drivers aged between 20 and 50 years participated in a driving simulator study that compared the efficacy, and drivers' subjective perception, of two active level crossing traffic control devices: flashing lights with boom barriers and standard traffic lights. Because of its common usage in most states in Australia, a stop sign-controlled level crossing served as the passive referent. Although crossing violations were less likely at the level crossings controlled by active devices than at those controlled by stop signs, both kinds of active control were associated with a similar number of violations. Further, the majority (72%) of drivers reported preferring flashing lights to traffic lights. Collectively, results indicate that the installation of traffic lights at real-world level crossings would not be likely to offer safety benefits over and above those provided already by flashing lights with boom barriers. Furthermore, the high rate of violations at passively controlled crossings strongly supports the continued practice of upgrading level crossings with active traffic control devices. Copyright © 2011 Elsevier Ltd. All rights reserved.

Composition and process for making an insulating refractory material

DOEpatents

Pearson, A.; Swansiger, T.G.

1998-04-28

A composition and process are disclosed for making an insulating refractory material. The composition includes calcined alumina powder, flash activated alumina powder, an organic polymeric binder and a liquid vehicle which is preferably water. Starch or modified starch may also be added. A preferred insulating refractory material made with the composition has a density of about 2.4--2.6 g/cm{sup 3} with reduced thermal conductivity, compared with tabular alumina. Of importance, the formulation has good abrasion resistance and crush strength during intermediate processing (commercial sintering) to attain full strength and refractoriness.

Flashes, floaters and fuzz.

PubMed

Nagendran, Sonali T; Thomas, Dhanes; Gurbaxani, Avinash

2013-02-01

Flashing lights (photopsia) and floaters are common visual phenomena and patients frequently present to hospital with these symptoms. This article provides a guide for the non-specialist to the different pathologies that may result in photopsia and floaters.

46 CFR 131.975 - Searchlights.

Code of Federal Regulations, 2014 CFR

2014-10-01

... § 131.975 Searchlights. No person may flash, or cause to be flashed, the rays of a searchlight or other blinding light onto the bridge or into the pilothouse of any vessel, OSV or other, under way. ...

46 CFR 131.975 - Searchlights.

Code of Federal Regulations, 2011 CFR

2011-10-01

... § 131.975 Searchlights. No person may flash, or cause to be flashed, the rays of a searchlight or other blinding light onto the bridge or into the pilothouse of any vessel, OSV or other, under way. ...

46 CFR 131.975 - Searchlights.

Code of Federal Regulations, 2010 CFR

2010-10-01

... § 131.975 Searchlights. No person may flash, or cause to be flashed, the rays of a searchlight or other blinding light onto the bridge or into the pilothouse of any vessel, OSV or other, under way. ...

46 CFR 131.975 - Searchlights.

Code of Federal Regulations, 2012 CFR

2012-10-01

... § 131.975 Searchlights. No person may flash, or cause to be flashed, the rays of a searchlight or other blinding light onto the bridge or into the pilothouse of any vessel, OSV or other, under way. ...

46 CFR 131.975 - Searchlights.

Code of Federal Regulations, 2013 CFR

2013-10-01

... § 131.975 Searchlights. No person may flash, or cause to be flashed, the rays of a searchlight or other blinding light onto the bridge or into the pilothouse of any vessel, OSV or other, under way. ...

Global Positioning System Synchronized Active Light Autonomous Docking System

NASA Technical Reports Server (NTRS)

Howard, Richard T. (Inventor); Book, Michael L. (Inventor); Bryan, Thomas C. (Inventor); Bell, Joseph L. (Inventor)

1996-01-01

A Global Positioning System Synchronized Active Light Autonomous Docking System (GPSSALADS) for automatically docking a chase vehicle with a target vehicle comprising at least one active light emitting target which is operatively attached to the target vehicle. The target includes a three-dimensional array of concomitantly flashing lights which flash at a controlled common frequency. The GPSSALADS further comprises a visual tracking sensor operatively attached to the chase vehicle for detecting and tracking the target vehicle. Its performance is synchronized with the flash frequency of the lights by a synchronization means which is comprised of first and second internal clocks operatively connected to the active light target and visual tracking sensor, respectively, for providing timing control signals thereto, respectively. The synchronization means further includes first and second Global Positioning System receivers operatively connected to the first and second internal clocks, respectively, for repeatedly providing simultaneous synchronization pulses to the internal clocks, respectively. In addition, the GPSSALADS includes a docking process controller means which is operatively attached to the chase vehicle and is responsive to the visual tracking sensor for producing commands for the guidance and propulsion system of the chase vehicle.

Global Positioning System Synchronized Active Light Autonomous Docking System

NASA Technical Reports Server (NTRS)

Howard, Richard (Inventor)

1994-01-01

A Global Positioning System Synchronized Active Light Autonomous Docking System (GPSSALADS) for automatically docking a chase vehicle with a target vehicle comprises at least one active light emitting target which is operatively attached to the target vehicle. The target includes a three-dimensional array of concomitantly flashing lights which flash at a controlled common frequency. The GPSSALADS further comprises a visual tracking sensor operatively attached to the chase vehicle for detecting and tracking the target vehicle. Its performance is synchronized with the flash frequency of the lights by a synchronization means which is comprised of first and second internal clocks operatively connected to the active light target and visual tracking sensor, respectively, for providing timing control signals thereto, respectively. The synchronization means further includes first and second Global Positioning System receivers operatively connected to the first and second internal clocks, respectively, for repeatedly providing simultaneous synchronization pulses to the internal clocks, respectively. In addition, the GPSSALADS includes a docking process controller means which is operatively attached to the chase vehicle and is responsive to the visual tracking sensor for producing commands for the guidance and propulsion system of the chase vehicle.

Determining optimum flash patterns for emergency service vehicles: an experimental investigation using high definition film.

PubMed

Turner, Sally; Wylde, Julie; Langham, Martin; Morrow, Andrew

2014-09-01

An investigation of how emergency vehicle lighting (EVL) can be improved is reported with reference to an analysis of police vehicle road traffic accidents (Study 1). In Study 2, 37 regular drivers were shown film clips of a marked police vehicle, in which flash rate (1 Hz, 4 Hz) and pattern (single, triple pulse) were varied on the blue Light Emitting Diode (LED) roofbar. Results indicate a 4 Hz flash rate conveys greater urgency than a 1 Hz rate, while a 1 Hz, single flash combination was ranked the least urgent of all combinations. Participants claimed they would leave significantly more space before pulling out in front of an approaching police car (gap acceptance) in the 4 Hz single pulse condition in comparison to other EVL combinations. The preliminary implications for which flash characteristics could prove most optimal for emergency service use are discussed with regard to effects on driver perception and expected driving behaviour. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

New multichannel kinetic spectrophotometer-fluorimeter with pulsed measuring beam for photosynthesis research.

PubMed

Bína, David; Litvín, Radek; Vácha, Frantisek; Siffel, Pavel

2006-06-01

A multichannel kinetic spectrophotometer-fluorimeter with pulsed measuring beam and differential optics has been constructed for measurements of light-induced absorbance and fluorescence yield changes in isolated chlorophyll-proteins, thylakoids and intact cells including algae and photosynthetic bacteria. The measuring beam, provided by a short (2 micros) pulse from a xenon flash lamp, is divided into a sample and reference channel by a broad band beam splitter. The spectrum in each channel is analyzed separately by a photodiode array. The use of flash measuring beam and differential detection yields high signal-to-noise ratio (noise level of 2 x 10(-4) in absorbance units per single flash) with negligible actinic effect. The instrument covers a spectral range between 300 and 1050 nm with a spectral resolution of 2.1, 6.4 or 12.8 nm dependent on the type of grating used. The optical design of the instrument enables measuring of the difference spectra during an actinic irradiation of samples with continuous light and/or saturation flashes. The time resolution of the spectrophotometer is limited by the length of Xe flash lamp pulses to 2 micros.

Flash/crazing effects on simulator pursuit tracking performance

NASA Astrophysics Data System (ADS)

Stamper, D. A.; Lund, D. J.; Levine, R. R.; Molchany, J. W.; Best, P.

1986-03-01

Day sights which are purposefully or inadvertently irradiated with laser radiation may become nonfunctional due to cracking or crazing of the optical glass. The degree of performance degradation may be related to the amount of damage to the glass and possible flash blindness from reradiation. Thirty-two male enlisted men and officers tracked a scale model tank through a constant arc at a simulated distance of 1 km, using a laboratory constructed viscous-damped tracking device. There were four crazing groups (4 men/group) under bright and dim ambient light conditions for a total of eight groups. Each man tracked the target during three flash/crazing and three crazing only trials, which were randomly presented during 30 trials. The simulated countermeasure which included the flash and crazing had dramatic effects on tracking performance, even under daylight conditions. Under the most severe degree of crazing, tracking performance was not possible under either ambient light condition. The relatively small amounts of laser radiation used to craze the BK-7 glass used in this study, which lead to significant performance decrements, demonstrates the potential impact of flash/crazing effects on operators of day sights.

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...

46 CFR 196.25-1 - Improper use prohibited.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Searchlights § 196.25-1 Improper use prohibited. (a) No person shall flash or cause to be flashed the rays of a searchlight or other blinding light onto the bridge or into the pilothouse of any vessel underway. ...

46 CFR 196.25-1 - Improper use prohibited.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Searchlights § 196.25-1 Improper use prohibited. (a) No person shall flash or cause to be flashed the rays of a searchlight or other blinding light onto the bridge or into the pilothouse of any vessel underway. ...

46 CFR 196.25-1 - Improper use prohibited.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Searchlights § 196.25-1 Improper use prohibited. (a) No person shall flash or cause to be flashed the rays of a searchlight or other blinding light onto the bridge or into the pilothouse of any vessel underway. ...

46 CFR 196.25-1 - Improper use prohibited.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Searchlights § 196.25-1 Improper use prohibited. (a) No person shall flash or cause to be flashed the rays of a searchlight or other blinding light onto the bridge or into the pilothouse of any vessel underway. ...

46 CFR 196.25-1 - Improper use prohibited.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Searchlights § 196.25-1 Improper use prohibited. (a) No person shall flash or cause to be flashed the rays of a searchlight or other blinding light onto the bridge or into the pilothouse of any vessel underway. ...

Fluorescence Lyman-Alpha Stratospheric Hygrometer (FLASH): application on meteorological balloons, long duration balloons and unmanned aerial vehicles.

NASA Astrophysics Data System (ADS)

Lykov, Alexey; Khaykin, Sergey; Yushkov, Vladimir; Efremov, Denis; Formanyuk, Ivan; Astakhov, Valeriy

The FLASH instrument is based on the fluorescent method, which uses H2O molecules photodissociation at a wavelength lambda=121.6 nm (Lalpha - hydrogen emission) followed by the measurement of the fluorescence of excited OH radicals. The source of Lyman-alpha radiation is a hydrogen discharge lamp while the detector of OH fluorescence at 308 -316 nm is a photomultiplier run in photon counting mode. The intensity of the fluorescent light as well as the instrument readings is directly proportional to the water vapor mixing ratio under stratospheric conditions with negligible oxygen absorption. Initially designed for rocket-borne application, FLASH has evolved into a light-weight balloon sonde (FLASH-B) for measurements in the upper troposphere and stratosphere on board meteorological and small plastic balloons. This configuration has been used in over 100 soundings at numerous tropical mid-latitude and polar locations within various international field campaigns. An airborne version of FLASH instrument is successfully utilized onboard stratospheric M55-Geophysica aircraft and tropospheric airborne laboratory YAK42-Roshydromet. The hygrometer was modified for application onboard stratospheric long-duration balloons (FLASH-LDB version). This version was successfully used onboard CNES super-pressure balloon launched from SSC Esrange in March 2007 and flown during 10 days. Special design for polar long duration balloon PoGOLite was created for testing work during polar day in June 2013. Installation and measurement peculiarities as well as observational results are presented. Observations of water vapour using FLASH-B instrument, being of high quality are rather costly as the payload recovery is often complicated and most of the time impossible. Following the goal to find a cost-efficient solution, FLASH was adapted for use onboard Unmanned Aerial Vehicles (UAV). This solution was only possible thanks to compactness and light-weight (0.5 kg) of FLASH instrument. The hygrometer was installed at the nose of a small GPS-controlled glider, which was lifted by a meteorological balloon into the stratosphere and released by a remote command. GPS-based flight control guides and lands the UAV at the launch point thereby allowing multiple usage of its payload. Another sounding platform allowing for multiple usage of the FLASH instrument is a GPS-guided paraglide. The results of measurements acquired in the test flights using different types of balloon-lifted UAVs are presented.

Optical countermeasures against CLOS weapon systems

NASA Astrophysics Data System (ADS)

Toet, Alexander; Benoist, Koen W.; van Lingen, Joost N. J.; Schleijpen, H. Ric M. A.

2013-10-01

There are many weapon systems in which a human operator acquires a target, tracks it and designates it. Optical countermeasures against this type of systems deny the operator the possibility to fulfill this visual task. We describe the different effects that result from stimulation of the human visual system with high intensity (visible) light, and the associated potential operational impact. Of practical use are flash blindness, where an intense flash of light produces a temporary "blind-spot" in (part of) the visual field, flicker distraction, where strong intensity and/or color changes at a discomfortable frequency are produced, and disability glare where a source of light leads to contrast reduction. Hence there are three possibilities to disrupt the visual task of an operator with optical countermeasures such as flares or lasers or a combination of these; namely, by an intense flash of light, by an annoying light flicker or by a glare source. A variety of flares for this purpose is now available or under development: high intensity flash flares, continuous burning flares or strobe flares which have an oscillating intensity. The use of flare arrays seems particularly promising as an optical countermeasure. Lasers are particularly suited to interfere with human vision, because they can easily be varied in intensity, color and size, but they have to be directed at the (human) target, and issues like pointing and eye-safety have to be taken into account. Here we discuss the design issues and the operational impact of optical countermeasures against human operators.

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...

Determination of chlorine in silicate rocks

USGS Publications Warehouse

Peck, L.C.

1959-01-01

In a rapid accurate method for the determination of chlorine in silicate rocks, the rock powder is sintered with a sodium carbonate flux containing zinc oxide and magnesium carbonate. The sinter cake is leached with water, the resulting solution is filtered, and the filtrate is acidified with nitric acid. Chlorine is determined by titrating this solution with mercuric nitrate solution using sodium nitroprusside as the indicator. The titration is made in the dark with a beam of light shining through the solution. The end point of the titration is found by visually comparing the intensity of this beam of light with that of a similar beam of light in a reference solution.

[Influence of compaction pressure and pre-sintering temperature on the machinability of zirconia ceramic].

PubMed

Huang, Huil; Li, Jing; Zhang, Fuqiang; Sun, Jing; Gao, Lian

2011-10-01

In order to make certain the compaction pressure as well as pre-sintering temperature on the machinability of the zirconia ceramic. 3 mol nano-size 3 mol yttria partially stabilized zirconia (3Y-TZP) powder were compacted at different isostatic pressure and sintered at different temperature. The cylindrical surface was traversed using a hard metal tool. Surface and edge quality were checked visually using light stereo microscopy. Pre-sintering temperature had the obviously influence on the machinability of 3Y-TZP. The cutting surface was smooth, and the integrality of edge was better when the pre-sintering temperature was chosen between 800 degrees C to 900 degrees C. Compaction pressure showed only a weak influence on machinability of 3Y-TZP blanks, but the higher compaction pressure result in the poor surface quality. The best machinability of pre-sintered zirconia body was found for 800-900 degrees C pre-sintering temperature, and 200-300 MPa compaction pressure.

Surface-structured diffuser by iterative down-size molding with glass sintering technology.

PubMed

Lee, Xuan-Hao; Tsai, Jung-Lin; Ma, Shih-Hsin; Sun, Ching-Cherng

2012-03-12

In this paper, a down-size sintering scheme for making high-performance diffusers with micro structure to perform beam shaping is presented and demonstrated. By using down-size sintering method, a surface-structure film is designed and fabricated to verify the feasibility of the sintering technology, in which up to 1/8 dimension reduction has been achieved. Besides, a special impressing technology has been applied to fabricate diffuser film with various materials and the transmission efficiency is as high as 85% and above. By introducing the diffuser into possible lighting applications, the diffusers have been shown high performance in glare reduction, beam shaping and energy saving.

[Study on the discharge properties of xeon flash lamp and experimental measurement].

PubMed

Zhao, You-Quan; Miao, Pei-Liang; He, Feng; Gu, Jian; Zhai, Rui-Wei

2014-07-01

The Xenon flash lamp is a new type of light source for analytical instrument. The present paper analyzed the discharge process of xenon flash lamp, presented the discharge test system, and conducted experimental measurement of the voltage, current and optical pulse signal in the process of discharge. The results show that in the preliminary discharge, the free electron concentration was at a low level, so the energy was at a low level, then following the gas discharge, numerous free electrons formed in the lamp, resultin in the increase in the concentration of free electrons, therefore discharge current rised rapidly and voltage reduced. The lamp released photons to generate light pulse in the moment of ionic recombination, The pulse xenon lamp light energy output and spectral characteristic is related to electron energy in recombination and combination level of xenon, if the input energy and the energy consumption of the xenon lamp is inconsistent, it will lead to repeated capacitor charging and discharging and produce oscillation waveform. This paper is very useful for understanding the process of xenon lamp discharge, optimizing the driver circuit and the production of xenon flash lamp.

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

PubMed

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

2017-10-01

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

32 CFR 707.7 - Submarine identification light.

Code of Federal Regulations, 2010 CFR

2010-07-01

... RULES WITH RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.7 Submarine identification light. Submarines may display, as a distinctive means of identification, an intermittent flashing amber beacon with...

Ocular Screening System

NASA Technical Reports Server (NTRS)

1987-01-01

Used to detect eye problems in children through analysis of retinal reflexes, the system incorporates image processing techniques. VISISCREEN's photorefractor is basically a 35 millimeter camera with a telephoto lens and an electronic flash. By making a color photograph, the system can test the human eye for refractive error and obstruction in the cornea or lens. Ocular alignment problems are detected by imaging both eyes simultaneously. Electronic flash sends light into the eyes and the light is reflected from the retina back to the camera lens. Photorefractor analyzes the retinal reflexes generated by the subject's response to the flash and produces an image of the subject's eyes in which the pupils are variously colored. The nature of a defect, where such exists, is identifiable by atrained observer's visual examination.

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...

Composition and process for making an insulating refractory material

DOEpatents

Pearson, Alan; Swansiger, Thomas G.

1998-04-28

A composition and process for making an insulating refractory material. The composition includes calcined alumina powder, flash activated alumina powder, an organic polymeric binder and a liquid vehicle which is preferably water. Starch or modified starch may also be added. A preferred insulating refractory material made with the composition has a density of about 2.4-2.6 g/cm.sup.3 with reduced thermal conductivity, compared with tabular alumina. Of importance, the formulation has good abrasion resistance and crush strength during intermediate processing (commercial sintering) to attain full strength and refractoriness, good abrasion resistance and crush strength.

Transparent ceramic photo-optical semiconductor high power switches

DOEpatents

Werne, Roger W.; Sullivan, James S.; Landingham, Richard L.

2016-01-19

A photoconductive semiconductor switch according to one embodiment includes a structure of sintered nanoparticles of a high band gap material exhibiting a lower electrical resistance when excited by light relative to an electrical resistance thereof when not exposed to the light. A method according to one embodiment includes creating a mixture comprising particles, at least one dopant, and at least one solvent; adding the mixture to a mold; forming a green structure in the mold; and sintering the green structure to form a transparent ceramic. Additional system, methods and products are also presented.

Discrimination of short-duration (two-pulse) flashes as a function of signal luminance and method of measurement.

DOT National Transportation Integrated Search

1971-11-01

The recent introduction of strobe lights for anticollision purposes raises the possibility of using temporal patterns of short duration flashes as information carrying signals. The current experiments are concerned with the detection of the minimum d...

Reaction time as a function of flash luminance and duration.

DOT National Transportation Integrated Search

1967-11-01

As a consequence of the high speeds of modern aircraft, pilots must respond quickly to signal lights from the ground or other aircraft during night flight. The present study was concerned with the relation of reaction time to flash luminance and dura...

Stimulus-dependent modulation of spontaneous low-frequency oscillations in the rat visual cortex.

PubMed

Huang, Liangming; Liu, Yadong; Gui, Jianjun; Li, Ming; Hu, Dewen

2014-08-06

Research on spontaneous low-frequency oscillations is important to reveal underlying regulatory mechanisms in the brain. The mechanism for the stimulus modulation of low-frequency oscillations is not known. Here, we used the intrinsic optical imaging technique to examine stimulus-modulated low-frequency oscillation signals in the rat visual cortex. The stimulation was presented monocularly as a flashing light with different frequencies and intensities. The phases of low-frequency oscillations in different regions tended to be synchronized and the rhythms typically accelerated within a 30-s period after stimulation. These phenomena were confined to visual stimuli with specific flashing frequencies (12.5-17.5 Hz) and intensities (5-10 mA). The acceleration and synchronization induced by the flashing frequency were more marked than those induced by the intensity. These results show that spontaneous low-frequency oscillations can be modulated by parameter-dependent flashing lights and indicate the potential utility of the visual stimulus paradigm in exploring the origin and function of low-frequency oscillations.

Production Process for Strong, Light Ceramic Tiles

NASA Technical Reports Server (NTRS)

Holmquist, G. R.; Cordia, E. R.; Tomer, R. S.

1985-01-01

Proportions of ingredients and sintering time/temperature schedule changed. Production process for lightweight, high-strength ceramic insulating tiles for Space Shuttle more than just scaled-up version of laboratory process for making small tiles. Boron in aluminum borosilicate fibers allows fusion at points where fibers contact each other during sintering, thereby greatly strengthening tiles structure.

Parametric Study of Diffusion-Enhancement Networks for Spatiotemporal Grouping in Real-Time Artificial Vision

DTIC Science & Technology

1993-04-01

suggesting it occurs in later visual motion processing (long-range or second-order system). STIMULUS PERCEPT L" FLASH DURATION FLASH DURATION (a) TIME ( b ...TIME Figure 2. Gamma motion. (a) A light of fixed spatial extent is illuminated then extim- guished. ( b ) The percept is of a light expanding and then...while smaller, type- B cells provide input to its parvocellular subdivision. From here the magnocellular pathway progresses up through visual cortex area V

Analysis of a four lamp flash system for calibrating multi-junction solar cells under concentrated light

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

Schachtner, Michael, E-mail: michael.schachtner@ise.fraunhofer.de; Prado, Marcelo Loyo; Reichmuth, S. Kasimir

2015-09-28

It has been known for a long time that the precise characterization of multi-junction solar cells demands spectrally tunable solar simulators. The calibration of innovative multi-junction solar cells for CPV applications now requires tunable solar simulators which provide high irradiation levels. This paper describes the commissioning and calibration of a flash-based four-lamp simulator to be used for the measurement of multi-junction solar cells with up to four subcells under concentrated light.

PERSONAL RADIATION MONITOR

DOEpatents

Dilworth, R.H.; Borkowski, C.J.

1961-12-26

A transistorized, fountain pen type radiation monitor to be worn on the person is described. Radiation produces both light flashes in a small bulb and an audible warning tone, the frequency of both the tone and light flashes being proportional to radiation intensity. The device is powered by a battery and a blocking oscillator step-up power supply The oscillator frequency- is regulated to be proportional to the radiation intensity, to provide adequate power in high radiation fields, yet minimize battery drain at low operating intensities. (AEC)

[Physical treatment methods for acne. Light, laser, photodynamic therapy and peeling].

PubMed

Borelli, C; Korting, H C

2010-02-01

The medical treatment of acne is generally sufficient to meet the expectations of acne patients. However, in a number of situations additional therapeutic approaches may be advisable. There are a wide variety of useful physical methods. They range from electromagnetic waves, usually light, to peeling and manual therapy. Phototherapy of acne includes not just visible light but also laser and flash lamp therapy. The present review provides an overview on the evidence. Visible light, in particular blue light, provides an effective option for treatment of inflammatory acne. Photodynamic therapy also is efficacious; however, it should not be used because of an unfavorable risk-benefit ratio. UV treatment of acne is obsolete. Newer studies on the use of a variety of laser systems and flash lamps have demonstrated in part rewarding results.

Flash LIDAR Systems for Planetary Exploration

NASA Astrophysics Data System (ADS)

Dissly, Richard; Weinberg, J.; Weimer, C.; Craig, R.; Earhart, P.; Miller, K.

2009-01-01

Ball Aerospace offers a mature, highly capable 3D flash-imaging LIDAR system for planetary exploration. Multi mission applications include orbital, standoff and surface terrain mapping, long distance and rapid close-in ranging, descent and surface navigation and rendezvous and docking. Our flash LIDAR is an optical, time-of-flight, topographic imaging system, leveraging innovations in focal plane arrays, readout integrated circuit real time processing, and compact and efficient pulsed laser sources. Due to its modular design, it can be easily tailored to satisfy a wide range of mission requirements. Flash LIDAR offers several distinct advantages over traditional scanning systems. The entire scene within the sensor's field of view is imaged with a single laser flash. This directly produces an image with each pixel already correlated in time, making the sensor resistant to the relative motion of a target subject. Additionally, images may be produced at rates much faster than are possible with a scanning system. And because the system captures a new complete image with each flash, optical glint and clutter are easily filtered and discarded. This allows for imaging under any lighting condition and makes the system virtually insensitive to stray light. Finally, because there are no moving parts, our flash LIDAR system is highly reliable and has a long life expectancy. As an industry leader in laser active sensor system development, Ball Aerospace has been working for more than four years to mature flash LIDAR systems for space applications, and is now under contract to provide the Vision Navigation System for NASA's Orion spacecraft. Our system uses heritage optics and electronics from our star tracker products, and space qualified lasers similar to those used in our CALIPSO LIDAR, which has been in continuous operation since 2006, providing more than 1.3 billion laser pulses to date.

Enhanced retinal responses in Huntington's disease patients.

PubMed

Pearl, Jocelynn R; Heath, Laura M; Bergey, Dani E; Kelly, John P; Smith, Corrie; Laurino, Mercy Y; Weiss, Avery; Price, Nathan D; LaSpada, Albert; Bird, Thomas D; Jayadev, Suman

2017-01-01

Huntington's disease (HD) is a fatal progressive neurodegenerative disease characterized by chorea, cognitive impairment and psychiatric symptoms. Retinal examination of HD patients as well as in HD animal models have shown evidence of retinal dysfunction. However, a detailed retinal study employing clinically available measurement tools has not been reported to date in HD. The goal of this study was to assess retinal responses measured by electroretinogram (ERG) between HD patients and controls and evaluate any correlation between ERG measurements and stage of disease. Eighteen patients and 10 controls with inclusion criteria of ages 18-70 years (average age HD subjects: 52.1 yrs and control subjects: 51.9 yrs) were recruited for the study. Subjects with previous history of retinal or ophthalmologic disease were excluded. Retinal function was examined by full-field ERG in both eyes of each subject. Amplitudes and latencies to increasing flash intensities in both light- and dark-adaptation were measured in all subjects. Statistical analyses employed generalized estimating equations, which account for repeated measures per subject. We analyzed the b-wave amplitudes of ERG response in all flash intensities and with 30 Hz flicker stimulation. We found statistically significant increased amplitudes in HD patients compared to controls at light-adapted (photopic) 24.2 and 60.9 cd.sec/m2 intensities, dark-adapted (scotopic, red flash) 0.22 cd.sec/m2 intensity, and a trend toward significance at light-adapted 30 Hz flicker. Furthermore, we found a significant increase in light-adapted ERG response from female compared to male HD patients, but no significant difference between gender amongst controls. We also noted a positive association between number of CAG repeats and ERG response at the smallest light adapted intensity (3.1 cd.sec/m2). ERG studies revealed significantly altered retinal responses at multiple flash intensities in subjects with an HD expansion allele compared to controls. Significant differences were observed with either light-adapted tests or the dark-adapted red flash which suggests that the enhanced responses in HD patients is specific to the cone photoreceptor pathway.

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. ...

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. ...

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. ...

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. ...

49 CFR 236.23 - Aspects and indications.

Code of Federal Regulations, 2014 CFR

2014-10-01

... shown by the position of semaphore blades, color of lights, position of lights, flashing of lights, or... light, shape and color of semaphore blades or any combination thereof, subject to the following conditions: (1) Night aspects of roadway signals, except qualifying appurtenances, shall be shown by lights...

49 CFR 236.23 - Aspects and indications.

Code of Federal Regulations, 2012 CFR

2012-10-01

... shown by the position of semaphore blades, color of lights, position of lights, flashing of lights, or... light, shape and color of semaphore blades or any combination thereof, subject to the following conditions: (1) Night aspects of roadway signals, except qualifying appurtenances, shall be shown by lights...

49 CFR 236.23 - Aspects and indications.

Code of Federal Regulations, 2013 CFR

2013-10-01

... shown by the position of semaphore blades, color of lights, position of lights, flashing of lights, or... light, shape and color of semaphore blades or any combination thereof, subject to the following conditions: (1) Night aspects of roadway signals, except qualifying appurtenances, shall be shown by lights...

49 CFR 236.23 - Aspects and indications.

Code of Federal Regulations, 2011 CFR

2011-10-01

... shown by the position of semaphore blades, color of lights, position of lights, flashing of lights, or... light, shape and color of semaphore blades or any combination thereof, subject to the following conditions: (1) Night aspects of roadway signals, except qualifying appurtenances, shall be shown by lights...

Light adaption of the cyclic GMP phosphodiesterase of frog photoreceptor membranes mediated by ATP and calcium ions

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

Kawamura, S.; Bownds, M.D.

1981-05-01

The light-activated guanosine 3',5'-cyclic monophosphate (cyclic GMP) phosphodiesterase (PDE) of frog photoreceptor membranes has been assayed by measuring the evolution of protons that accompanies cyclic GMP hydrolysis. The validity of this assay has been confirmed by comparison with an isotope assay used in previous studies (Robinson et al. 1980. J. Gen. Physiol. 76: 631-645). The PDE activity elicited by either flash or continuous dim illumination is reduced if ATP is added to outer segment suspensions. This desensitization is most pronounced at low calcium levels. In 10(-9) M Ca/sup + +/, with 0.5 mM ATP and 0.5 mM GTP present, PDEmore » activity remains almost constant as dim illumination and rhodopsin bleaching continue. At intermediate Ca/sup + +/ levels (10-7-10-5M) the activity slowly increases during illumination. Finally, in 10(-4) and PDE activity is more a reflection of the total number of rhodopsin molecules bleached than of the rate of the rhodopsin bleaching. At intermediate or low calcium levels a short-lived inhibitory process is revealed by observing a nonlinear summation of responses of the enzyme to closely spaced flashes of light. Each flash makes PDE activity less responsive to successive flashes, and a steady state is obtained in which activation and inactivation are balanced. It is suggested that calcium and ATP regulation of PDE play a role in the normal light adaption processes of frog photoreceptor membranes.« less

Estimating the crash reduction and vehicle dynamics effects of flashing LED stop signs : final report.

DOT National Transportation Integrated Search

2014-01-01

A flashing LED stop sign is essentially a normal octagonal stop sign with light emitted diodes (LED) on the : stop signs corners. A hierarchical Bayes observational before/after study found an estimated reduction of : about 41.5% in right-angle cr...

33 CFR 88.12 - Public safety activities.

Code of Federal Regulations, 2011 CFR

2011-07-01

...; traffic control; salvage; firefighting; medical assistance; assisting disabled vessels; and search and... alternately flashing red and yellow light signal. This identification light signal must be located so that it does not interfere with the visibility of the vessel's navigation lights. The identification light...

33 CFR 88.12 - Public safety activities.

Code of Federal Regulations, 2010 CFR

2010-07-01

...; traffic control; salvage; firefighting; medical assistance; assisting disabled vessels; and search and... alternately flashing red and yellow light signal. This identification light signal must be located so that it does not interfere with the visibility of the vessel's navigation lights. The identification light...

The photocurrent, noise and spectral sensitivity of rods of the monkey Macaca fascicularis.

PubMed Central

Baylor, D A; Nunn, B J; Schnapf, J L

1984-01-01

Visual transduction in rods of the cynomolgus monkey, Macaca fascicularis, was studied by recording membrane current from single outer segments projecting from small pieces of retina. Light flashes evoked transient outward-going photocurrents with saturating amplitudes of up to 34 pA. A flash causing twenty to fifty photoisomerizations gave a response of half the saturating amplitude. The response-stimulus relation was of the form 1-e-x where x is flash strength. The response to a dim flash usually had a time to peak of 150-250 ms and resembled the impulse response of a series of six low-pass filters. From the average spectral sensitivity of ten rods the rhodopsin was estimated to have a peak absorption near 491 nm. The spectral sensitivity of the rods was in good agreement with the average human scotopic visibility curve determined by Crawford (1949), when the human curve was corrected for lens absorption and self-screening of rhodopsin. Fluctuations in the photocurrent evoked by dim lights were consistent with a quantal event about 0.7 pA in peak amplitude. A steady light causing about 100 photoisomerizations s-1 reduced the flash sensitivity to half the dark-adapted value. At higher background levels the rod rapidly saturated. These results support the idea that dim background light desensitizes human scotopic vision by a mechanism central to the rod outer segments while scotopic saturation may occur within the outer segments. Recovery of the photocurrent after bright flashes was marked by quantized step-like events. The events had the properties expected if bleached rhodopsin in the disks occasionally caused an abrupt blockage of the dark current over about one-twentieth of the length of the outer segment. It is suggested that superposition of these events after bleaching may contribute to the threshold elevation measured psychophysically. The current in darkness showed random fluctuations which disappeared in bright light. The continuous component of the noise had a variance of about 0.03 pA2 and a power spectrum that fell to half near 3 Hz. A second component, consisting of discrete events resembling single-photon responses, was estimated to occur at a rate of 0.006 s-1. It is suggested that the continuous component of the noise may be removed from scotopic vision by a thresholding operation near the rod output. PMID:6512705

The photocurrent, noise and spectral sensitivity of rods of the monkey Macaca fascicularis.

PubMed

Baylor, D A; Nunn, B J; Schnapf, J L

1984-12-01

Visual transduction in rods of the cynomolgus monkey, Macaca fascicularis, was studied by recording membrane current from single outer segments projecting from small pieces of retina. Light flashes evoked transient outward-going photocurrents with saturating amplitudes of up to 34 pA. A flash causing twenty to fifty photoisomerizations gave a response of half the saturating amplitude. The response-stimulus relation was of the form 1-e-x where x is flash strength. The response to a dim flash usually had a time to peak of 150-250 ms and resembled the impulse response of a series of six low-pass filters. From the average spectral sensitivity of ten rods the rhodopsin was estimated to have a peak absorption near 491 nm. The spectral sensitivity of the rods was in good agreement with the average human scotopic visibility curve determined by Crawford (1949), when the human curve was corrected for lens absorption and self-screening of rhodopsin. Fluctuations in the photocurrent evoked by dim lights were consistent with a quantal event about 0.7 pA in peak amplitude. A steady light causing about 100 photoisomerizations s-1 reduced the flash sensitivity to half the dark-adapted value. At higher background levels the rod rapidly saturated. These results support the idea that dim background light desensitizes human scotopic vision by a mechanism central to the rod outer segments while scotopic saturation may occur within the outer segments. Recovery of the photocurrent after bright flashes was marked by quantized step-like events. The events had the properties expected if bleached rhodopsin in the disks occasionally caused an abrupt blockage of the dark current over about one-twentieth of the length of the outer segment. It is suggested that superposition of these events after bleaching may contribute to the threshold elevation measured psychophysically. The current in darkness showed random fluctuations which disappeared in bright light. The continuous component of the noise had a variance of about 0.03 pA2 and a power spectrum that fell to half near 3 Hz. A second component, consisting of discrete events resembling single-photon responses, was estimated to occur at a rate of 0.006 s-1. It is suggested that the continuous component of the noise may be removed from scotopic vision by a thresholding operation near the rod output.

Technical brief: Pump-probe paradigm in an integrating cavity to study photodecomposition processes

PubMed Central

Betts-Obregon, Brandi; Tsin, Andrew T.; DeSa, Richard J.

2016-01-01

Purpose Assaying photodecomposition is challenging because light must be used to initiate the photodamage and light must be used to monitor the photodecomposition. The experimental requirements are as follows: 1) During exposure of the actinic beam, continuously monitor the spectral characteristics of the sample, 2) uniformly expose the reactants to the actinic source, 3) obtain informative spectra in the presence of light scatter, and 4) achieve sufficient sensitivity for dilute reactants. Traditional spectrophotometers cannot address these issues due to sample turbidity, the inability to uniformly expose the cuvette contents to the incident beam, the inability to simultaneously perform spectral scans, and inherent low sensitivity. Here, we describe a system that meets these challenges in a practical way. Methods Light access to a 8.6 ml quartz integrating sphere containing 10 µM all-trans retinol in PBS was provided by three ports at right angles allowing for the following: 1) actinic light delivery from light-emitting diodes (LEDs) firing at 100 pulses/sec, 2) entry of a separate scanning beam at 100 scans/sec (10,000 µsec scan time) via an OLIS RSM 1000 ultraviolet/visual (UV/Vis) rapid-scanning spectrophotometer (RSM), and 3) light exit to the detector photomultiplier. The RSM spectral intermediate slit was partially covered to allow for a “dark” period of 2,000 µsec when no scanning light was admitted to the cuvette. During that interval, the LED was flashed, and the photomultiplier was temporarily blocked by a perforated spinning shutter disk. The absorbance per centimeter, which is increased due to the internal reflectance of the integrating sphere compared to a standard 1 cm rectangular cuvette, was calculated according to Fry et al. (2010) Applied Optics 49:575. Retinoid photodecomposition was confirmed with high-performance liquid chromatography (HPLC). Results Using the RSM to trigger the LED flash and photomultiplier shutter closure during the “dark” period allowed actinic flashes to be placed between scans. Exposure of the all-trans retinol to 366 nm flashes resulted in marked reduction in absorbance and a blue shift of the λmax. A white LED, despite its higher photon output, did not support all-trans retinol photolysis. Singular value decomposition (SVD) analysis revealed three spectral intermediates with mechanism, I -> II -> III. HPLC analysis of the reactants at the beginning and the conclusion of the light exposure confirmed the retinol photodecomposition. Conclusions The highly reflecting cavity acts as a multipass cuvette that markedly increased the light path length and, thus, sensitivity. Triggering the LED during a dark period within the scan time allowed the actinic flashes to be interleafed between scans in a pump-probe paradigm. Furthermore, the entire sample was exposed to scan beam and actinic flashes, which is not possible in traditional spectrophotometers. Finally, the integrating cavity cuvette allowed use of turbid samples. SVD was useful for resolving spectral intermediates. Although the identity of the intermediates was not determined here, the ability to define molecular intermediates during photodecomposition reactions will allow future studies to isolate and identify the degradation products and determine the mechanism of light-induced retinoid degradation and that of retinoid-binding protein-mediated photoprotection. PMID:27559291

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

PubMed

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

2013-05-22

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

Flash Flood Trail near Parras, Coahuila, Mexico

NASA Image and Video Library

1991-12-01

Evidence of a recent flash flood can be seen in the form of light brown sediment that flowed down gullies and mountain sides forming ponds of debris over agricultural areas in the broad valley near the town of Parras (26.5N, 102.5W). This part of Mexico has extensive vineyards, orchards and both dry land and irrigated agriculture. Based on the photo, it appears that flash flood waters damaged some 300 square miles of property in this area alone.

Flash Flood Trail near Parras, Coahuila, Mexico

NASA Technical Reports Server (NTRS)

1991-01-01

Evidence of a recent flash flood can be seen in the form of light brown sediment that flowed down gullies and mountain sides forming ponds of debris over agricultural areas in the broad valley near the town of Parras (26.5N, 102.5W). This part of Mexico has extensive vineyards, orchards and both dry land and irrigated agriculture. Based on the photo, it appears that flash flood waters damaged some 300 square miles of property in this area alone.

The membrane current of single rod outer segments.

PubMed

Baylor, D A; Lamb, T D; Yau, K W

1979-03-01

1. Outer segments of individual rods in the retina of the toad, Bufo marinus, were drawn into a glass pipette to record the membrane current. 2. Light flashes evoked transient outward currents. The peak response amplitude was related to flash intensity by a Michaelis equation with half-saturating intensity about 1 photon mum-2. 3. The saturating response amplitude ranged up to 27 pA and corresponded closely to complete suppression of the steady inward current present in darkness. 4. For a given cell the saturating response amplitude varied linearly with the length of outer segment within the pipette. This is consistent with a uniform density of light-sensitive channels and negligible gradient of membrane potential along the outer segment. 5. Responses to bright flashes never showed the relaxation from an initial peak seen previously in intracellular voltage recordings, suggesting that the conductance change responsible for the relaxation does not occur in the outer segment. 6. Responses to local illumination of only the recorded outer segment were very similar to those obtained with diffuse light at the same intensity, indicating that peripheral rods made little contribution to the responses. 7. The spectral sensitivity of 'red' rods was consistent with a retinal1-based pigment with lambda max = 498 +/- 2 nm. 8. The kinetics of the response were consistent with four stages of delay affecting action of the internal transmitter. Responses were faster at the basal end of the outer segment than at the distal tip. 9. Background light reduced the sensitivity to a superposed dim test flash and shortened the time course of the response, indicating that adapting light modifies the kinetics and gain of the transduction mechanism within the outer segment. 10. Responses to dim lights exhibited pronounced fluctuations which are attributed in the succeeding paper (Baylor, Lamb & Yau, 1979) to the quantal nature of light.

Effects of backscatter of brief high intensity light on physiological responses of instrument-rated pilots and non-pilots.

DOT National Transportation Integrated Search

1972-03-01

Thirty-nine human subjects were exposed to reptitive backscatter light stimulation (off a white wall or fog) from a Grimes capacitance discharge airplane anticollision light flashing at 1.27 Hertz. Both tonic (light stimulus absent) and phasic (light...

Modeling experimental plasma diagnostics in the FLASH code: Thomson scattering

NASA Astrophysics Data System (ADS)

Weide, Klaus; Flocke, Norbert; Feister, Scott; Tzeferacos, Petros; Lamb, Donald

2017-10-01

Spectral analysis of the Thomson scattering of laser light sent into a plasma provides an experimental method to quantify plasma properties in laser-driven plasma experiments. We have implemented such a synthetic Thomson scattering diagnostic unit in the FLASH code, to emulate the probe-laser propagation, scattering and spectral detection. User-defined laser rays propagate into the FLASH simulation region and experience scattering (change in direction and frequency) based on plasma parameters. After scattering, the rays propagate out of the interaction region and are spectrally characterized. The diagnostic unit can be used either during a physics simulation or in post-processing of simulation results. FLASH is publicly available at flash.uchicago.edu. U.S. DOE NNSA, U.S. DOE NNSA ASC, U.S. DOE Office of Science and NSF.

Fast light-evoked potential from leaves.

PubMed

Ebrey, T G

1967-03-24

When a leaf is illuminated with an intense flash of light, an elec trical response with a time course in milliseconds can be recorded. This re sponse was obtained between two wick electrodes placed at different positions on top of the leaf, with the entire leaf uniformly illuminated by the flash. During the first millisecond or so, the electrode nearer the apex of the leaf always became negative with respect to an electrode at the base, which indi cates that the voltage-generating source is fixed longitudinally in the leaf.

Potential Use of a Bayesian Network for Discriminating Flash Type from Future GOES-R Geostationary Lightning Mapper (GLM) data

NASA Technical Reports Server (NTRS)

Solakiewiz, Richard; Koshak, William

2008-01-01

Continuous monitoring of the ratio of cloud flashes to ground flashes may provide a better understanding of thunderstorm dynamics, intensification, and evolution, and it may be useful in severe weather warning. The National Lighting Detection Network TM (NLDN) senses ground flashes with exceptional detection efficiency and accuracy over most of the continental United States. A proposed Geostationary Lightning Mapper (GLM) aboard the Geostationary Operational Environmental Satellite (GOES-R) will look at the western hemisphere, and among the lightning data products to be made available will be the fundamental optical flash parameters for both cloud and ground flashes: radiance, area, duration, number of optical groups, and number of optical events. Previous studies have demonstrated that the optical flash parameter statistics of ground and cloud lightning, which are observable from space, are significantly different. This study investigates a Bayesian network methodology for discriminating lightning flash type (ground or cloud) using the lightning optical data and ancillary GOES-R data. A Directed Acyclic Graph (DAG) is set up with lightning as a "root" and data observed by GLM as the "leaves." This allows for a direct calculation of the joint probability distribution function for the lighting type and radiance, area, etc. Initially, the conditional probabilities that will be required can be estimated from the Lightning Imaging Sensor (LIS) and the Optical Transient Detector (OTD) together with NLDN data. Directly manipulating the joint distribution will yield the conditional probability that a lightning flash is a ground flash given the evidence, which consists of the observed lightning optical data [and possibly cloud data retrieved from the GOES-R Advanced Baseline Imager (ABI) in a more mature Bayesian network configuration]. Later, actual GLM and NLDN data can be used to refine the estimates of the conditional probabilities used in the model; i.e., the Bayesian network is a learning network. Methods for efficient calculation of the conditional probabilities (e.g., an algorithm using junction trees), finding data conflicts, goodness of fit, and dealing with missing data will also be addressed.

A LIS Validation Study at the KSC-ER using LDAR and Field Mill Data

NASA Technical Reports Server (NTRS)

Koshak, William J.; Christian, Hugh J.; Krider, E. Philip

1999-01-01

The chance of having the TRMM satellite pass over east central Florida when there is lightning over the NASA Kennedy Space Center (KSC) and USAF Eastern Range (ER) is small; however, such a condition did occur on September 21, 1998 (Day 264). Starting at about 20:40 GMT, the Lightning Imaging Sensor (LIS) reported 5 flashes during a 90 second interval that the KSC-ER was within the sensor field of view. Ground-based instrumentation, the Lightning Detection and Ranging (LDAR) system and a network of electric field mills (FM), detected 6 flashes in the same interval. In this paper, we will compare the times and locations of the optical pulses that were detected by LIS with the times and locations of RF sources (LDAR) and the charges that were deposited by the flash (FM network). We will show that LIS responded to all flashes that the LDAR and FM network detected; however, two discharges that were separated by less than 1 second in time and by about 10 km in space were grouped as one flash by the LIS data processing algorithm. In spite of the fact that all flashes occurred near the edge of the LIS field of view, the locations of the LIS events were consistent with both the LDAR and FM locations (the latter are usually within 1-2 kilometers of each other and often are co-located). Two of the 5 flashes reported by LIS were shifted north by about 8 km from the corresponding LDAR and FM locations. The LIS flash times tended to be after the first LDAR pulse was detected and before the last, and the integrated light signal (per LIS event) was surprisingly constant over the 5 flashes that were detected by LIS. In the future, we plan to study more correlated events and will try to determine whether and how the LIS light signal is related to the charge transfer in the flash and/or the number and spatial extent of RF sources.

Nighttime highway construction illumination.

DOT National Transportation Integrated Search

2014-08-01

The nighttime driving environment, consisting of roadway illumination, signs, vehicle lighting and markers, delineators : and flashing lights, can be complex or even confusing for both pedestrians and drivers. The nighttime construction : environment...

Chromogenic behaviors of the Humboldt squid (Dosidicus gigas) studied in situ with an animal-borne video package.

PubMed

Rosen, Hannah; Gilly, William; Bell, Lauren; Abernathy, Kyler; Marshall, Greg

2015-01-15

Dosidicus gigas (Humboldt or jumbo flying squid) is an economically and ecologically influential species, yet little is known about its natural behaviors because of difficulties in studying this active predator in its oceanic environment. By using an animal-borne video package, National Geographic's Crittercam, we were able to observe natural behaviors in free-swimming D. gigas in the Gulf of California with a focus on color-generating (chromogenic) behaviors. We documented two dynamic displays without artificial lighting at depths of up to 70 m. One dynamic pattern, termed 'flashing' is characterized by a global oscillation (2-4 Hz) of body color between white and red. Flashing was almost always observed when other squid were visible in the video frame, and this behavior presumably represents intraspecific signaling. Amplitude and frequency of flashing can be modulated, and the phase relationship with another squid can also be rapidly altered. Another dynamic display termed 'flickering' was observed whenever flashing was not occurring. This behavior is characterized by irregular wave-like activity in neighboring patches of chromatophores, and the resulting patterns mimic reflections of down-welled light in the water column, suggesting that this behavior may provide a dynamic type of camouflage. Rapid and global pauses in flickering, often before a flashing episode, indicate that flickering is under inhibitory neural control. Although flashing and flickering have not been described in other squid, functional similarities are evident with other species. © 2015. Published by The Company of Biologists Ltd.

PIAS1 interacts with FLASH and enhances its co-activation of c-Myb

PubMed Central

2011-01-01

Background FLASH is a huge nuclear protein involved in various cellular functions such as apoptosis signalling, NF-κB activation, S-phase regulation, processing of histone pre-mRNAs, and co-regulation of transcription. Recently, we identified FLASH as a co-activator of the transcription factor c-Myb and found FLASH to be tightly associated with active transcription foci. As a huge multifunctional protein, FLASH is expected to have many interaction partners, some which may shed light on its function as a transcriptional regulator. Results To find additional FLASH-associated proteins, we performed a yeast two-hybrid (Y2H) screening with FLASH as bait and identified the SUMO E3 ligase PIAS1 as an interaction partner. The association appears to involve two distinct interaction surfaces in FLASH. We verified the interaction by Y2H-mating, GST pulldowns, co-IP and ChIP. FLASH and PIAS1 were found to co-localize in nuclear speckles. Functional assays revealed that PIAS1 enhances the intrinsic transcriptional activity of FLASH in a RING finger-dependent manner. Furthermore, PIAS1 also augments the specific activity of c-Myb, and cooperates with FLASH to further co-activate c-Myb. The three proteins, FLASH, PIAS1, and c-Myb, are all co-localized with active RNA polymerase II foci, resembling transcription factories. Conclusions We conclude that PIAS1 is a common partner for two cancer-related nuclear factors, c-Myb and FLASH. Our results point to a functional cooperation between FLASH and PIAS1 in the enhancement of c-Myb activity in active nuclear foci. PMID:21338522

47 CFR 17.56 - Maintenance of lighting equipment.

Code of Federal Regulations, 2010 CFR

2010-10-01

... § 17.56 Maintenance of lighting equipment. (a) Replacing or repairing of lights, automatic indicators or automatic control or alarm systems shall be accomplished as soon as practicable. (b) The flash tubes in a high intensity obstruction lighting system shall be replaced whenever the peak effective...

Photodynamic Therapy for Cancer Cells Using a Flash Wave Light Xenon Lamp

NASA Astrophysics Data System (ADS)

Kimura, Makoto; Kashikura, Kasumi; Yokoi, Satomi; Koiwa, Yumiko; Tokuoka, Yoshikazu; Kawashima, Norimichi

We determined photodynamic therapy (PDT) efficacy using a flash wave (FW) and a continuous wave (CW) light, of which the fluence rate was 70 W/cm2, for murine thymic lymphoma cells (EL-4) cultivated in vitro. The irradiation frequency and the pulse width of the FW light were in the range of 1-32 Hz and less than one millisecond, respectively. 5-Aminolevulinic acid-induced protoporphyrin IX (ALA-PpIX) was used as a photosensitizer. When EL-4 with ALA administration was irradiated by the light for 4 h (irradiation fluence: 1.0J/cm2), the survival rate of EL-4 by the FW light was lower than that by the CW light, except for the FW light with irradiation frequency of 32 Hz, and decreased gradually with decreasing irradiation frequency. Moreover, the FW light, especially at lower irradiation frequency, was superior to the CW light for the generation of singlet oxygen in an aqueous PpIX solution. Therefore, thehigher PDT efficacy for EL-4 of the FW light would be caused by the greater generation of singlet oxygen in the cells.

Shapes displayed with durations in the microsecond range do not obey Bloch's law of temporal summation

PubMed Central

Greene, Ernest; Ogden, R. Todd

2013-01-01

Shape patterns were displayed with simultaneous brief flashes from a light-emitting diode array. Flash durations in the microsecond range and luminous intensities were adjusted to vary the degree of successful shape recognition. Four experiments were conducted to test whether Bloch's law would apply in this task. Bloch's law holds that for very brief flashes the perceptual threshold is determined by the total number of photons being delivered, i.e., there is reciprocity of intensity and duration. The present results did not find that effectiveness of flashes was based on the total quantity of photons, as predicted by Bloch's law. Additionally, the evidence points to a visual mechanism that has ultra-high temporal precision that either registers the rate of photon flux or the duration of flashes. PMID:24349700

33 CFR 88.11 - Law enforcement vessels.

Code of Federal Regulations, 2011 CFR

2011-07-01

... display a flashing blue light when engaged in direct law enforcement or public safety activities. This light must be located so that it does not interfere with the visibility of the vessel's navigation lights. (b) The blue light described in this section may be displayed by law enforcement vessels of the...

33 CFR 88.11 - Law enforcement vessels.

Code of Federal Regulations, 2014 CFR

2014-07-01

... display a flashing blue light when engaged in direct law enforcement or public safety activities. This light must be located so that it does not interfere with the visibility of the vessel's navigation lights. (b) The blue light described in this section may be displayed by law enforcement vessels of the...

33 CFR 88.11 - Law enforcement vessels.

Code of Federal Regulations, 2013 CFR

2013-07-01

... display a flashing blue light when engaged in direct law enforcement or public safety activities. This light must be located so that it does not interfere with the visibility of the vessel's navigation lights. (b) The blue light described in this section may be displayed by law enforcement vessels of the...

33 CFR 88.11 - Law enforcement vessels.

Code of Federal Regulations, 2012 CFR

2012-07-01

... display a flashing blue light when engaged in direct law enforcement or public safety activities. This light must be located so that it does not interfere with the visibility of the vessel's navigation lights. (b) The blue light described in this section may be displayed by law enforcement vessels of the...

33 CFR 88.11 - Law enforcement vessels.

Code of Federal Regulations, 2010 CFR

2010-07-01

... display a flashing blue light when engaged in direct law enforcement or public safety activities. This light must be located so that it does not interfere with the visibility of the vessel's navigation lights. (b) The blue light described in this section may be displayed by law enforcement vessels of the...

Mechanisms of phosphene generation in ocular proton therapy as related to space radiation exposure

NASA Astrophysics Data System (ADS)

Chuard, D.; Anthonipillai, V.; Dendale, R.; Nauraye, C.; Khan, E.; Mabit, C.; De Marzi, L.; Narici, L.

2016-08-01

Particle therapy provides an opportunity to study the human response to space radiation in ground-based facilities. On this basis, a study of light flashes analogous to astronauts' phosphenes reported by patients undergoing ocular proton therapy has been undertaken. The influence of treatment parameters on phosphene generation was investigated for 430 patients treated for a choroidal melanoma at the proton therapy centre of the Institut Curie (ICPO) in Orsay, France, between 2008 and 2011. 60% of them report light flashes, which are predominantly (74%) blue. An analysis of variables describing the patient's physiology, properties of the tumour and dose distribution shows that two groups of tumour and beam variables are correlated with phosphene occurrence. Physiology is found to have no influence on flash triggering. Detailed correlation study eventually suggests a possible twofold mechanism of phosphene generation based on (i) indirect Cerenkov light in the bulk of the eye due to nuclear interactions and radioactive decay and (ii) direct excitation of the nerve fibres in the back of the eye and/or radical excess near the retina.

Visual and Kinesthetic Components of Pursuit-Tracking Performance.

ERIC Educational Resources Information Center

Thorsheim, Howard I.; And Others

Seventy-five subjects were trained on a pursuit rotor for 10 trials, with ambient illumination from a strobe light flashing at frequencies of either 2,5,10,15, or 20 per second. A transfer trial followed, with a strobe flashing frequency of 10 per second for all subjects. Results supported hypotheses derived from Adams' closed-loop theory of motor…

Effect of Annealing Time of YAG:Ce3+ Phosphor on White Light Chromaticity Values

NASA Astrophysics Data System (ADS)

Abd, Husnen R.; Hassan, Z.; Ahmed, Naser M.; Almessiere, Munirah Abdullah; Omar, A. F.; Alsultany, Forat H.; Sabah, Fayroz A.; Osman, Ummu Shuhada

2018-02-01

Yttrium and aluminium nitrate phosphors doped with cerium nitrate and mixed with urea (fuel) are prepared by using microwave-induced combustion synthesis according to the formula Y(3-0.06)Al5O12:0.06Ce3+ (YAG:Ce3+) to produce white light emitting diodes by conversion from blue indium gallium nitride-light emitting diode chips. The sintering time with fixed temperature (1050°C) for phosphor powder was optimized and found to be 5 h. The crystallinity, structure, chemical composition, luminescent properties with varying currents densities and chromaticity were characterized by x-ray diffraction, field emission-scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, photoluminescence emission, electroluminescence and standard CIE 1931 chromaticity diagram, respectively. The energy levels of Ce3+ in YAG were discussed based on its absorption and excitation spectra. The results show that the obtained YAG:Ce3+ phosphor sintered for 5 h has good crystallinity with pure phase, low agglomerate with spherical shaped particles and strong yellow emission, offering cool-white LED with tuneable correlated color temperature and a good color rendering index compared to those prepared by sintering for 2 h and as-prepared phosphor powders.

Mutants of Arabidopsis thaliana with decreased amplitude in their phototropic response

NASA Technical Reports Server (NTRS)

Khurana, J. P.; Ren, Z.; Steinitz, B.; Parks, B.; Best, T. R.; Poff, K. L.

1989-01-01

Two mutants of Arabidopsis thaliana have been identified with decreased phototropism to 450-nanometer light. Fluence-response relationships for these strains (ZR8 and ZR19) to single and multiple flashes of light show thresholds, curve shapes, and fluence for maximum curvature in first positive' phototropism which are the same as those of the wild type. Similarly, there is no alteration from the wild type in the kinetics of curvature or in the optimum dark period separating sequential flashes in a multiple flash regimen. In addition, in both strains, gravitropism is decreased compared to the wild type by an amount which is comparable to the decrease in phototropism. Based on reciprocal backcrosses, it appears that the alteration is due to a recessive nuclear mutation. It is suggested that ZR8 and ZR19 represent alterations in some step analogous to an amplifier, downstream of the photoreceptor pigment, and common to both phototropism and gravitropism.

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...

Human visual response to nuclear particle exposures

NASA Technical Reports Server (NTRS)

Tobias, C. A.; Budinger, T. F.; Lyman, J. T.

1972-01-01

Experiments with accelerated helium ions were performed in an effort to localize the site of initial radiation interactions in the eye that lead to light flash observations by astronauts during spaceflight. The character and efficiency of helium ion induction of visual sensations depended on the state of dark adaptation of the retina; also, the same events were seen with different efficiencies and details when particle flux density changed. It was concluded that fast particles cause interactions in the retina, particularly in the receptor layer, and thus give rise to the sensations of light flashes, streaks, and supernovae.

Apollo-Soyuz light-flash observations.

PubMed

Budinger, T F; Tobias, C A; Huesman, R H; Upham, F T; Wieskamp, T F; Hoffman, R A

1977-01-01

While dark adapted, two Apollo-Soyuz astronauts saw eighty-two light flash events during a complete 51 degrees orbit which passed near the north magnetic pole and through the South Atlantic Anomaly. The frequency of events at the polar parts of the orbit is 25 times that noted in equatorial latitudes and no increased frequency was noted in the South Atlantic Anomaly at the 225-km altitude. The expected flux of heavy particles at the northern and southern points is 1-2 min-1 per eye, and the efficiency for seeing HZE particles which were below the Cerenkov threshold is 50%.

Eye light flashes on the Mir space station.

PubMed

Avdeev, S; Bidoli, V; Casolino, M; De Grandis, E; Furano, G; Morselli, A; Narici, L; De Pascale, M P; Picozza, P; Reali, E; Sparvoli, R; Boezio, M; Carlson, P; Bonvicini, W; Vacchi, A; Zampa, N; Castellini, G; Fuglesang, C; Galper, A; Khodarovich, A; Ozerov, Yu; Popov, A; Vavilov, N; Mazzenga, G; Ricci, M; Sannita, W G; Spillantini, P

2002-04-01

The phenomenon of light flashes (LF) in eyes for people in space has been investigated onboard Mir. Data on particles hitting the eye have been collected with the SilEye detectors, and correlated with human observations. It is found that a nucleus in the radiation environment of Mir has roughly a 1% probability to cause an LF, whereas the proton probability is almost three orders of magnitude less. As a function of LET, the LF probability increases above 10 keV/micrometer, reaching about 5% at around 50 keV/micrometer. c 2002 Elsevier Science Ltd. All rights reserved.

Radiation measurement in the environment of FLASH using passive dosimeters

NASA Astrophysics Data System (ADS)

Mukherjee, B.; Rybka, D.; Makowski, D.; Lipka, T.; Simrock, S.

2007-08-01

Sophisticated electronic devices comprising sensitive microelectronic components have been installed in the close proximity of the 720 MeV superconducting electron linear accelerator (linac) driving the FLASH (Free Electron Laser in Hamburg), presently in operation at DESY in Hamburg. Microelectronic chips are inherently vulnerable to ionizing radiation, usually generated during routine operation of high-energy particle accelerator facilities like the FLASH. Hence, in order to assess the radiation effect on microelectronic chips and to develop suitable mitigation strategy, it becomes imperative to characterize the radiation field in the FLASH environment. We have evaluated the neutron and gamma energy (spectra) and dose distributions at critical locations in the FLASH tunnel using superheated emulsion (bubble) detectors, GaAs light emitting diodes (LED), LiF-thermoluminescence dosimeters (TLD) and radiochromic (Gafchromic EBT) films. This paper highlights the application of passive dosimeters for an accurate analysis of the radiation field produced by high-energy electron linear accelerators.

Electrophysiology and Innervation of the Photosensitive Epistellar Body in the Lesser Octopus Eledone cirrhosa.

PubMed

Cobb, C S; Williamson, R

1998-08-01

The innervation and responses to light of the cephalopod epistellar body were investigated in preparations isolated from the stellate ganglia of the lesser or northern octopus, Eledone cirrhosa. Extracellular generator potentials in response to flashes of light were recorded from these photosensitive vesicles, with the amplitude of the response being found to be dependent upon the intensity of the flash and the level of ambient illumination. Intracellular recordings from photoreceptor cells of the epistellar body showed that they had resting potentials of about -49 +/- 7 mV (mean +/- SD, n = 43) and were depolarized by flashes of white, but not red (>650 nm) light. The evoked depolarization consisted of a transient component, followed by a steady plateau in which the amplitude of the depolarization was well correlated with the log of the stimulus intensity. The evoked depolarizations induced action potentials in the photoreceptor cells, with the frequency of firing being well correlated with the stimulus intensity. The morphologies of individual photoreceptor cells were visualized by intracellular injections of the fluorescent dye Lucifer yellow, and the path of the epistellar nerve across the stellate ganglion, into the pallial nerve, toward the brain was traced using the lipophilic dye Di-I. This pathway was confirmed physiologically by recording light-evoked responses from the cut end of the pallial nerve.

Novel approach to real-time flash photolysis and confocal [Ca2+] imaging

PubMed Central

Sobie, Eric A.; Kao, Joseph P.Y.; Lederer, W. J.

2008-01-01

Flash photolysis of “caged” compounds using ultraviolet light is a powerful experimental technique for producing rapid changes in concentrations of bioactive signaling molecules. Studies that employ this technique have used diverse strategies for controlling the spatial and temporal application of light to the specimen. Here we describe a new system for flash photolysis that delivers light from a pulsed, adjustable intensity laser through an optical fiber coupled into the epifluorescence port of a commercial confocal microscope. Photolysis is achieved with extremely brief (5 ns) pulses of ultraviolet light (355 nm) that can be synchronized with respect to confocal laser scanning. The system described also localizes the UV intensity spatially so that uncaging only occurs in defined sub-cellular regions; moreover, since the microscope optics are used in localization, the photolysis volume can be easily adjusted. Experiments performed on rat ventricular myocytes loaded with the Ca2+ indicator fluo-3 and the Ca2+ cage NP-EGTA demonstrate the system's capabilities. Localized intracellular increases in [Ca2+] can trigger sarcoplasmic reticular Ca2+ release events such as Ca2+ sparks and, under certain conditions, regenerative Ca2+ waves. This relatively simple and inexpensive system is therefore a useful tool for examining local signaling in heart and other tissues. PMID:17323075

Surface hardening of Al alloys through controlled ball-milling and sintering.

PubMed

Kim, Seek Hyeoun; Kim, Yong Jin; Ahn, Jung-Ho

2012-07-01

One of the drawbacks of aluminum and its alloys is the lack of proper heat-treatment for surface-hardening. In the present work, a new and simple method of hardening the surface of aluminum and its alloys was developed. Low-energy ball-milling using specific process control agents (PCAs) was employed, using subsequent sintering in a controlled atmosphere. The PCAs in the present work were very effective both for milling and the formation of hard nanocrystalline dispersoids during sintering. The residual oxygen in a sintering atmosphere also played an important role in the formation of AIN or Al-O-N dispersoids. Through the proper control of the processing atmosphere and PCAs, the hardness and thickness of the hardened layers could be adjusted. The results of the wear test showed that the present aluminum alloys can be effectively utilized as light-weight components with a good wear resistance. Furthermore, the present method involves a simple forming process of die-compaction and sintering.

The effect of impurities elements on titanium alloy (Ti-6Al-4V) MIM sintered part properties

NASA Astrophysics Data System (ADS)

Ahmad, M. Azmirruddin; Jabir, M.; Johari, N.; Ibrahim, R.; Hamidi, N.

2017-12-01

The titanium alloys (Ti-6Al-4V) compact were fabricated by Metal Injection Molding (MIM). However, the real challenge of MIM processing for titanium alloy is its affinity to be contaminated by interstitial light elements such as oxygen and carbon which could degrade the mechanical properties of sintered titanium alloy such as its tensile strength and ductility. The sintering temperature effect on carbon and oxygen content that affects its physical and mechanical properties of the sintered titanium alloy was studied. The titanium MIM brown specimen was sintered at four different sintering temperatures which are 1100 °C, 1150 °C, 1200 °C and 1250 °C for 4 hours under furnace control atmosphere. The experimental result indicated that the specimen which has been made from 100% gas atomized powder have a relative density of 92.2 % - 97.6 %, the range of porosity percent around 2.38 %-3.84 %. Ultimate tensile strength of 873.11 MPa - 1007.19 MPa and ductility percent in range of 1.89 %-3.46 %. The titanium alloy MIM specimen which was sintered at 1150 °C contained 0.145 % of carbon and 0.143 % of oxygen possess the highest value of density and tensile strength, with value of 4.344 gcm-3 and 1007.2 MPa respectively. Meanwhile, the titanium alloy MIM specimen which was sintered at 1200 °C contains 0.130 % of carbon and 0.127 % of oxygen, has the highest percentage of ductility with 3.46 %. The carbon content level increased as the sintering temperature increased due to decomposition of high molecule weight of residue binder system which could not be eliminated during solvent extraction debinding process and sintered at low temperature. Contrarily, the oxygen content level indicates a decrease as the sintering temperature increased. Briefly, the sintering temperature could influence the physical and mechanical properties of titanium alloy MIM sintered specimen as it influences the oxygen and carbon content level in the alloys.

Irradiation resistance of silicon carbide joint at light water reactor–relevant temperature

DOE PAGES

Koyanagi, T.; Katoh, Y.; Kiggans, J. O.; ...

2017-03-10

We fabricated and irradiated monolithic silicon carbide (SiC) to SiC plate joints with neutrons at 270–310 °C to 8.7 dpa for SiC. The joining methods included solid state diffusion bonding using titanium and molybdenum interlayers, SiC nanopowder sintering, reaction sintering with a Ti-Si-C system, and hybrid processing of polymer pyrolysis and chemical vapor infiltration (CVI). All the irradiated joints exhibited apparent shear strength of more than 84 MPa on average. Significant irradiation-induced cracking was found in the bonding layers of the Ti and Mo diffusion bonds and Ti-Si-C reaction sintered bond. Furthermore, the SiC-based bonding layers of the SiC nanopowdermore » sintered and hybrid polymer pyrolysis and CVI joints all showed stable microstructure following the irradiation.« less

340nm UV LED excitation in time-resolved fluorescence system for europium-based immunoassays detection

NASA Astrophysics Data System (ADS)

Rodenko, Olga; Fodgaard, Henrik; Tidemand-Lichtenberg, Peter; Pedersen, Christian

2017-02-01

In immunoassay analyzers for in-vitro diagnostics, Xenon flash lamps have been widely used as excitation light sources. Recent advancements in UV LED technology and its advantages over the flash lamps such as smaller footprint, better wall-plug efficiency, narrow emission spectrum, and no significant afterglow, have made them attractive light sources for gated detection systems. In this paper, we report on the implementation of a 340 nm UV LED based time-resolved fluorescence system based on europium chelate as a fluorescent marker. The system performance was tested with the immunoassay based on the cardiac marker, TnI. The same signal-to-noise ratio as for the flash lamp based system was obtained, operating the LED below specified maximum current. The background counts of the system and its main contributors were measured and analyzed. The background of the system of the LED based unit was improved by 39% compared to that of the Xenon flash lamp based unit, due to the LEDs narrower emission spectrum and longer pulse width. Key parameters of the LED system are discussed to further optimize the signal-to-noise ratio and signal-to-background, and hence the sensitivity of the instrument.

Improvement of the electrochromic response of a low-temperature sintered dye-modified porous electrode using low-resistivity indium tin oxide nanoparticles

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

Watanabe, Yuichi, E-mail: yuichi.watanabe@aist.go.jp; Suemori, Kouji; Hoshino, Satoshi

2016-06-15

An indium tin oxide (ITO) nanoparticle-based porous electrode sintered at low temperatures was investigated as a transparent electrode for electrochromic displays (ECDs). The electrochromic (EC) response of the dye-modified ITO porous electrode sintered at 150 °C, which exhibited a generally low resistivity, was markedly superior to that of a conventional dye-modified TiO{sub 2} porous electrode sintered at the same temperature. Moreover, the EC characteristics of the dye-modified ITO porous electrode sintered at 150 °C were better than those of the high-temperature (450 °C) sintered conventional dye-modified TiO{sub 2} porous electrode. These improvements in the EC characteristics of the dye-modified ITO porous electrode aremore » attributed to its lower resistivity than that of the TiO{sub 2} porous electrodes. In addition to its sufficiently low resistivity attained under the sintering conditions required for flexible ECD applications, the ITO porous film had superior visible-light transparency and dye adsorption capabilities. We conclude that the process temperature, resistivity, optical transmittance, and dye adsorption capability of the ITO porous electrode make it a promising transparent porous electrode for flexible ECD applications.« less

Development of Macroscale Models of UO 2 Fuel Sintering and Densification using Multiscale Modeling and Simulation

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

Greenquist, Ian; Tonks, Michael

2016-10-01

Light water reactor fuel pellets are fabricated using sintering to final densities of 95% or greater. During reactor operation, the porosity remaining in the fuel after fabrication decreases further due to irradiation-assisted densification. While empirical models have been developed to describe this densification process, a mechanistic model is needed as part of the ongoing work by the NEAMS program to develop a more predictive fuel performance code. In this work we will develop a phase field model of sintering of UO 2 in the MARMOT code, and validate it by comparing to published sintering data. We will then add themore » capability to capture irradiation effects into the model, and use it to develop a mechanistic model of densification that will go into the BISON code and add another essential piece to the microstructure-based materials models. The final step will be to add the effects of applied fields, to model field-assisted sintering of UO 2. The results of the phase field model will be validated by comparing to data from field-assisted sintering. Tasks over three years: 1. Develop a sintering model for UO 2 in MARMOT 2. Expand model to account for irradiation effects 3. Develop a mechanistic macroscale model of densification for BISON« less

33 CFR 83.22 - Visibility of lights (Rule 22).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 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 special flashing light, 2 miles. (b) Vessels of 12 meters or more in length but less than 50 meters in...

33 CFR 83.22 - Visibility of lights (Rule 22).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 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 special flashing light, 2 miles. (b) Vessels of 12 meters or more in length but less than 50 meters in...

33 CFR 83.22 - Visibility of lights (Rule 22).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 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 special flashing light, 2 miles. (b) Vessels of 12 meters or more in length but less than 50 meters in...

33 CFR 83.22 - Visibility of lights (Rule 22).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 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 special flashing light, 2 miles. (b) Vessels of 12 meters or more in length but less than 50 meters in...

Phototoxic effects of commercial photographic flash lamp on rat eyes.

PubMed

Inoue, Makoto; Shinoda, Kei; Ohde, Hisao; Tezuka, Keiji; Hida, Tetsuo

2006-11-01

To determine whether exposure of the cornea and retina of rats to flashes from a commercial photographic flash lamp is phototoxic. Sprague-Dawley rats were exposed to 10, 100, or 1,000 flashes of the OPTICAM 16M photographic flash lamp (Fujikoeki, Japan) placed 0.1, 1, or 3 m from the eyes. Corneal damage was assessed by a fluorescein staining score, and the retinal damage by eletroretinography (ERG) and histology before and 24 h after exposure. Exposure of the eyes to 1,000 flashes at 0.1 m increased the fluorescein staining score significantly (P = 0.009, the Mann-Whitney test). Scanning electron microscopy (SEM) of the cornea showed a detachment of the epithelial cells from the surface after this exposure. The amplitude of the a-wave was decreased significantly by 23.0% (P = 0.026) of the amplitude before the exposure, and the b-wave by 19.7% (P = 0.0478) following 1,000 flashes at 0.1 m but not by the other exposures. TUNEL-positive cells were present in the outer nuclear layer only after the extreme exposure, but no significant decrease in retinal thickness was seen under any condition. The fluorescein staining score and ERGs recovered to control levels within 1 week. Light exposure to a photographic flash lamp does not induce damage to the cornea and retina except when they are exposed to 1,000 flashes at 0.1 m.

Field Evaluation of Locomotive Conspicuity Lights

DOT National Transportation Integrated Search

1975-05-01

Flashing xenon strobe lamps were installed on locomotives in revenue service as a means of alerting motorists to the hazards they are approaching at a rail-highway grade crossing. Effectiveness of these lights in attracting motorists' attention was e...

The evolution of adult light emission color in North American fireflies

PubMed Central

Hall, David W.; Sander, Sarah E.; Pallansch, Jennifer C.; Stanger-Hall, Kathrin F.

2016-01-01

Firefly species (Lampyridae) vary in the color of their adult bioluminescence. It has been hypothesized that color is selected to enhance detection by conspecifics. One mechanism to improve visibility of the signal is to increase contrast against ambient light. High contrast implies that fireflies active early in the evening will emit yellower luminescence to contrast against ambient light reflected from green vegetation, especially in habitats with high vegetation cover. Another mechanism to improve visibility is to use reflection off the background to enhance the light signal. Reflectance predicts that sedentary females will produce greener light to maximize reflection off the green vegetation on which they signal. To test these predictions, we recorded over 7500 light emission spectra and determined peak emission wavelength for 675 males, representing 24 species, at 57 field sites across the Eastern United States. We found support for both hypotheses: males active early in more vegetated habitats produced yellower flashes in comparison to later-active males with greener flashes. Further, in 2 of the 8 species with female data, female light emissions were significantly greener as compared to males. PMID:27412777

Parietal disruption alters audiovisual binding in the sound-induced flash illusion.

PubMed

Kamke, Marc R; Vieth, Harrison E; Cottrell, David; Mattingley, Jason B

2012-09-01

Selective attention and multisensory integration are fundamental to perception, but little is known about whether, or under what circumstances, these processes interact to shape conscious awareness. Here, we used transcranial magnetic stimulation (TMS) to investigate the causal role of attention-related brain networks in multisensory integration between visual and auditory stimuli in the sound-induced flash illusion. The flash illusion is a widely studied multisensory phenomenon in which a single flash of light is falsely perceived as multiple flashes in the presence of irrelevant sounds. We investigated the hypothesis that extrastriate regions involved in selective attention, specifically within the right parietal cortex, exert an influence on the multisensory integrative processes that cause the flash illusion. We found that disruption of the right angular gyrus, but not of the adjacent supramarginal gyrus or of a sensory control site, enhanced participants' veridical perception of the multisensory events, thereby reducing their susceptibility to the illusion. Our findings suggest that the same parietal networks that normally act to enhance perception of attended events also play a role in the binding of auditory and visual stimuli in the sound-induced flash illusion. Copyright © 2012 Elsevier Inc. All rights reserved.

Meteoroids Impact the Moon

NASA Technical Reports Server (NTRS)

Moser, D. E.

2017-01-01

Most meteoroids are broken up by Earth's atmosphere before they reach the ground. The Moon, however, has little-to-no atmosphere to prevent meteoroids from impacting the lunar surface. Upon impact they excavate a crater and generate a plume of debris. A flash of light at the moment of impact can also be seen. Meteoroids striking the Moon create an impact flash observable by telescopes here on Earth. NASA observers use telescopes at the Automated Lunar and Meteor Observatory (ALaMO) to routinely monitor the Moon for impact flashes each month when the lunar phase is right. Flashes recorded by two telescope simultaneously rule out false signals from cosmic rays and satellites. Over 400 impact flashes have been observed by NASA since 2005. This map shows the location of each flash. No observations are made near the poles or center line. On average, one impact is observed every two hours. The brightest and longest-lasting impact flash was observed in Mare Imbrium on March 17, 2013. The imaging satellite Lunar Reconnaissance Orbiter, in orbit around the Moon, discovered the fresh crater created by this impact. The crater is 60 across and was caused by a meteoroid 9 inches in diameter likely traveling at a speed of 57,000 mph!

Blue light filtered white light induces depression-like responses and temporary spatial learning deficits in rats.

PubMed

Meng, Qinghe; Lian, Yuzheng; Jiang, Jianjun; Wang, Wei; Hou, Xiaohong; Pan, Yao; Chu, Hongqian; Shang, Lanqin; Wei, Xuetao; Hao, Weidong

2018-04-18

Ambient light has a vital impact on mood and cognitive functions. Blue light has been previously reported to play a salient role in the antidepressant effect via melanopsin. Whether blue light filtered white light (BFW) affects mood and cognitive functions remains unclear. The present study aimed to investigate whether BFW led to depression-like symptoms and cognitive deficits including spatial learning and memory abilities in rats, and whether they were associated with the light-responsive function in retinal explants. Male Sprague-Dawley albino rats were randomly divided into 2 groups (n = 10) and treated with a white light-emitting diode (LED) light source and BFW light source, respectively, under a standard 12 : 12 h L/D condition over 30 days. The sucrose consumption test, forced swim test (FST) and the level of plasma corticosterone (CORT) were employed to evaluate depression-like symptoms in rats. Cognitive functions were assessed by the Morris water maze (MWM) test. A multi-electrode array (MEA) system was utilized to measure electro-retinogram (ERG) responses induced by white or BFW flashes. The effect of BFW over 30 days on depression-like responses in rats was indicated by decreased sucrose consumption in the sucrose consumption test, an increased immobility time in the FST and an elevated level of plasma CORT. BFW led to temporary spatial learning deficits in rats, which was evidenced by prolonged escape latency and swimming distances in the spatial navigation test. However, no changes were observed in the short memory ability of rats treated with BFW. The micro-ERG results showed a delayed implicit time and reduced amplitudes evoked by BFW flashes compared to the white flash group. BFW induces depression-like symptoms and temporary spatial learning deficits in rats, which might be closely related to the impairment of light-evoked output signals in the retina.

Unique Lighting Handbook.

ERIC Educational Resources Information Center

Edmund Scientific Co., Barrington, NJ.

For those who wish to enter the world of light shows, this handbook provides facts, ideas, techniques, suggestions, and sources for the many hard-to-get materials and products. Blacklight, flashing light, musicvision, and lumia (the anti-shape) are discussed. Instructions are given on how to create special effects with overhead projectors, 35mm.…

Apollo-Soyuz light-flash observations. [ionizing radiation effects measurement

NASA Technical Reports Server (NTRS)

Budinger, T. F.; Tobias, C. A.; Huesman, R. H.; Upham, F. T.; Wieskamp, T. F.; Hoffman, R. A.

1977-01-01

While dark adapted, two Apollo-Soyuz astronauts saw eighty-two light flash events during a complete 51 deg orbit which passed near the north magnetic pole and through the South Atlantic Anomaly. The frequency of events at the polar parts of the orbit is 25 times that noted in equatorial latitudes and no increased frequency was noted in the South Atlantic Anomaly at the 225-km altitude. The expected flux of heavy particles at the northern and southern points is 1-2/min per eye, and the efficiency for seeing high Z-high energy (HZE) particles which were below the Cerenkov threshold is 50%.

THz pulses from 4th generation X-ray light sources: Perspectives for fully synchronized THz pump X-ray probe experiments

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

Gensch, M.

2010-02-03

In this paper the prospects of terahertz (THz) pulses generated at 4th generation X-ray light sources are presented on the example of recent results from a prototype set-up at the soft X-ray FEL FLASH. It is shown, that the THz pulses from the relativistic ultra short electron bunches have unique properties, that at FLASH are utilized for novel THz pump X-ray probe experiments with a robust few fs resolution. Based on these experiences it is discussed, how future facilities can benefit from implementation of similar or further improved instrumentation.

Fast low-level light pulses from the night sky observed with the SKYFLASH program

NASA Astrophysics Data System (ADS)

Winckler, J. R.; Franz, R. C.; Nemzek, R. J.

1993-05-01

This paper presents further discussion of and new data on fast subvisual increases in the luminosity of the night sky described in our previous papers. A detailed technical description of the simple telescopic photometers used in the project SKYFLASH and their mode of operation including the detection of polarized Rayleigh-scattered flashes is provided. Distant lightning storms account for many of the events, and the complex relations between short and long luminous pulses with and without sferics are shown by examples from a new computerized data system, supplemented by two low-light-level TV cameras. Of particular interest are the previously observed 'long' events having a slow rise and fall, 20-ms duration, and showing small polarization and no coincident sferic. A group of such events on September 22-23 during the invasion of U.S. coasts by Hurricane Hugo, is discussed in detail. The recently observed 'plume' cloud-top-to-stratosphere lightning event is suggested as a possible source type for these flashes. An alternative source may be exploding meteors, recently identified during SKYFLASH observations by low-light-level television techniques as the origin of some sky-wide flash events described herein.

Fast low-level light pulses from the night sky observed with the SKYFLASH program

NASA Technical Reports Server (NTRS)

Winckler, J. R.; Franz, R. C.; Nemzek, R. J.

1993-01-01

This paper presents further discussion of and new data on fast subvisual increases in the luminosity of the night sky described in our previous papers. A detailed technical description of the simple telescopic photometers used in the project SKYFLASH and their mode of operation including the detection of polarized Rayleigh-scattered flashes is provided. Distant lightning storms account for many of the events, and the complex relations between short and long luminous pulses with and without sferics are shown by examples from a new computerized data system, supplemented by two low-light-level TV cameras. Of particular interest are the previously observed 'long' events having a slow rise and fall, 20-ms duration, and showing small polarization and no coincident sferic. A group of such events on September 22-23 during the invasion of U.S. coasts by Hurricane Hugo, is discussed in detail. The recently observed 'plume' cloud-top-to-stratosphere lightning event is suggested as a possible source type for these flashes. An alternative source may be exploding meteors, recently identified during SKYFLASH observations by low-light-level television techniques as the origin of some sky-wide flash events described herein.

Visual evoked potential in RCS rats with Okayama University-type retinal prosthesis (OUReP™) implantation.

PubMed

Alamusi; Matsuo, Toshihiko; Hosoya, Osamu; Uchida, Tetsuya

2017-06-01

Photoelectric dye-coupled polyethylene film, designated Okayama University type-retinal prosthesis or OUReP™, generates light-evoked surface electric potentials and stimulates neurons. The dye-coupled films or plain films were implanted subretinally in both eyes of 10 Royal College of Surgeons rats with hereditary retinal dystrophy at the age of 6 weeks. Visual evoked potentials in response to monocular flashing light stimuli were recorded from cranially-fixed electrodes, 4 weeks and 8 weeks after the implantation. After the recording, subretinal film implantation was confirmed histologically in 7 eyes with dye-coupled films and 7 eyes with plain films. The recordings from these 7 eyes in each group were used for statistical analysis. The amplitudes of visual evoked potentials in the consecutive time points from 125 to 250 ms after flash were significantly larger in the 7 eyes with dye-coupled film implantation, compared to the 7 eyes with plain film implantation at 8 weeks after the implantation (P < 0.05, repeated-measure ANOVA). The photoelectric dye-coupled polyethylene film, as retinal prosthesis, gave rise to visual evoked potential in response to flashing light.

Interactions of Prosthetic and Natural Vision in Animals With Local Retinal Degeneration

PubMed Central

Lorach, Henri; Lei, Xin; Galambos, Ludwig; Kamins, Theodore; Mathieson, Keith; Dalal, Roopa; Huie, Philip; Harris, James; Palanker, Daniel

2015-01-01

Purpose Prosthetic restoration of partial sensory loss leads to interactions between artificial and natural inputs. Ideally, the rehabilitation should allow perceptual fusion of the two modalities. Here we studied the interactions between normal and prosthetic vision in a rodent model of local retinal degeneration. Methods Implantation of a photovoltaic array in the subretinal space of normally sighted rats induced local degeneration of the photoreceptors above the chip, and the inner retinal neurons in this area were electrically stimulated by the photovoltaic implant powered by near-infrared (NIR) light. We studied prosthetic and natural visually evoked potentials (VEP) in response to simultaneous stimulation by NIR and visible light patterns. Results We demonstrate that electrical and natural VEPs summed linearly in the visual cortex, and both responses decreased under brighter ambient light. Responses to visible light flashes increased over 3 orders of magnitude of contrast (flash/background), while for electrical stimulation the contrast range was limited to 1 order of magnitude. The maximum amplitude of the prosthetic VEP was three times lower than the maximum response to a visible flash over the same area on the retina. Conclusions Ambient light affects prosthetic responses, albeit much less than responses to visible stimuli. Prosthetic representation of contrast in the visual scene can be encoded, to a limited extent, by the appropriately calibrated stimulus intensity, which also depends on the ambient light conditions. Such calibration will be important for patients combining central prosthetic vision with natural peripheral sight, such as in age-related macular degeneration. PMID:26618643

Flash Inactivation of Oxygen Evolution

PubMed Central

Frasch, Wayne D.; Cheniae, George M.

1980-01-01

Brief saturating light flashes were used to probe the mechanism of inactivation of O2 evolution by Tris in chloroplasts. Maximum inactivation with a single flash and an oscillation with period of four on subsequent flashes was observed. Analyses of the oscillations suggested that only the charge-collecting O2-evolving catalyst of photosystem II (S2-state) was a target of inactivation by Tris. This conclusion was supported by the following observations: (a) hydroxylamine preequilibration caused a three-flash delay in the inactivation pattern; (b) the lifetimes of the Tris-inactivable and S2-states were similar; and (c) reagents accelerating S2 deactivation decreased the lifetime of the inactivable state. Inactivation proved to be moderated by F, the precursor of Signal IIs, as shown by a one flash delay with chloroplasts having high abundance of F. Evidence was obtained for cooperativity effects in inactivation and NH3 was shown to be a competitive inhibitor of the Tris-induced inactivation. S2-dependent inactivation was inhibited by glutaraldehyde fixation of chloroplasts, possibly suggesting that inactivation proceeds via conformational changes of the S2-state. PMID:16661270

EXACT DOSE X-IRRADIATION OF VARIOUS REGIONS OF THE HEAD AND VISUAL SENSATIONS--X-RAY LOCATION METHOD OF STUDY OF THE REACTIVITY OF THE CENTRAL NERVOUS SYSTEM

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

Gurtovoi, G.K.; Burdianskaya, E.O.

1960-01-01

The primary substrate excited by threshold doses of x radiation of the normal human eye causes perception of a light flash in the retinal region. The threshold dose for the retina is about 1 mr; the threshold absorbed dose is about 1 mrad. Persons with a removed eyeball, on irradiation of the operated region with a frontal x-ray beam, perceive a flash of light at definite doses of radiation. Six persons taking part in an experiment saw a flash at doses of 17 to 150 mr (different observers saw flash at different doses) and did not see flash at dosesmore » of 5 to 90 mr. The cause of x-ray phosphene on frontal irradiation of the region of the removed eye with threshold doses is neither the reactivity of the optic nerve stump, the reactivity of the parts of the brain irradiated, nor the sensitivity of the skin receptors. In the cases considered, the cause of x-ray phosphene was irradiation of the retina of the nomnal eye by scattered x rays. The averaged coefficient of scatter was about 2%. On irradiation of the occiptal regions of the brain in subjects with normal eyes at a dose of about 150 mr, one subject perceived a flash of light. In this case, the absorbed dose for the occipital regions of the brain was about 40 mrad. The reason for this phenomenon must be explored. Stimulation of the cerebral formations (after atrophic changes in the visual tract and cortex) by x radia tion with a dose of up to 3 r, did not cause visual sensations. With the disposition of the beam, the absorbed dose for the chiasma was about 1 rad and for the occipital regions about 0.2 rad. In the study of threshold visual sensation and their causes on x irradiation of various regions of the head, it is important to apply defined doses of radiation. Scatter of the x rays in the head must be taken into consideration. (auth)« less

The electrical response of turtle cones to flashes and steps of light.

PubMed

Baylor, D A; Hodgkin, A L; Lamb, T D

1974-11-01

1. The linear response of turtle cones to weak flashes or steps of light was usually well fitted by equations based on a chain of six or seven reactions with time constants varying over about a 6-fold range.2. The temperature coefficient (Q(10)) of the reciprocal of the time to peak of the response to a flash was 1.8 (15-25 degrees C), corresponding to an activation energy of 10 kcal/mole.3. Electrical measurements with one internal electrode and a balancing circuit gave the following results on red-sensitive cones of high resistance: resistance across cell surface in dark 50-170 MOmega; time constant in dark 4-6.5 msec. The effect of a bright light was to increase the resistance and time constant by 10-30%.4. If the cell time constant, resting potential and maximum hyperpolarization are known, the fraction of ionic channels blocked by light at any instant can be calculated from the hyperpolarization and its rate of change. At times less than 50 msec the shape of this relation is consistent with the idea that the concentration of a blocking molecule which varies linearly with light intensity is in equilibrium with the fraction of ionic channels blocked.5. The rising phase of the response to flashes and steps of light covering a 10(5)-fold range of intensities is well fitted by a theory in which the essential assumptions are that (i) light starts a linear chain of reactions leading to the production of a substance which blocks ionic channels in the outer segment, (ii) an equilibrium between the blocking molecules and unblocked channels is established rapidly, and (iii) the electrical properties of the cell can be represented by a simple circuit with a time constant in the dark of about 6 msec.6. Deviations from the simple theory which occur after 50 msec are attributed partly to a time-dependent desensitization mechanism and partly to a change in saturation potential resulting from a voltage-dependent change in conductance.7. The existence of several components in the relaxation of the potential to its resting level can be explained by supposing that the ;substance' which blocks light sensitive ionic channels is inactivated in a series of steps.

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

NASA Astrophysics Data System (ADS)

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

2018-05-01

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

Mutants of Arabidopsis thaliana with decreased amplitude in their phototropic response

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

Khurana, J.P.; Ren, Zhangling; Steinitz, B.

1989-10-01

Two mutants of Arabidopsis thaliana have been identified with decreased phototropism to 450-nanometer light. Fluence-response relationships for these strains (ZR8 and ZR19) to single and multiple flashes of light show thresholds, curve shapes, and fluence for maximum curvature in first positive phototropism which are the same as those of the wild type. Similarly, there is no alteration from the wild type in the kinetics of curvature or in the optimum dark period separating sequential flashes in a multiple flash regimen. In addition, in both strains, gravitropism is decreased compared to the wild type by an amount which is comparable tomore » the decrease in phototropism. Based on reciprocal backcrosses, it appears that the alteration is due to a recessive nuclear mutation. It is suggested that ZR8 and ZR19 represent alterations in some step analogous to an amplifier, downstream of the photoreceptor pigment, and common to both phototropism and gravitropism.« less

Neutron position-sensitive scintillation detector

DOEpatents

Strauss, Michael G.; Brenner, Raul

1984-01-01

A device is provided for mapping one- and two-dimensional distributions of neutron-positions in a scintillation detector. The device consists of a lithium glass scintillator coupled by an air gap and a light coupler to an array of photomultipliers. The air gap concentrates light flashes from the scintillator, whereas the light coupler disperses this concentrated light to a predetermined fraction of the photomultiplier tube array.

49 CFR Appendix B to Part 234 - Alternate Methods of Protection Under 49 CFR 234.105(c), 234.106, and 234.107(c)

Code of Federal Regulations, 2010 CFR

2010-10-01

... Protection Under 49 CFR 234.105(c), 234.106, and 234.107(c) [This is a summary—see body of text for complete... pair of lights designed to flash alternatively, one light does not work (and back-lights from other...

A Little Flash (of) Light

ERIC Educational Resources Information Center

Moyer, Richard; Everett, Susan

2010-01-01

The flashlight is a simple device that is composed of a lightbulb, usually two cells connected in series, a housing, a switch, and a reflector for the light. All flashlights essentially use these parts to complete a circuit that converts the stored chemical energy in the cells to light energy. In this lesson, students will take apart an…

Miniature, mobile X-ray computed radiography system

DOEpatents

Watson, Scott A; Rose, Evan A

2017-03-07

A miniature, portable x-ray system may be configured to scan images stored on a phosphor. A flash circuit may be configured to project red light onto a phosphor and receive blue light from the phosphor. A digital monochrome camera may be configured to receive the blue light to capture an article near the phosphor.

Taking Snapshots of Photosynthetic Water Oxidation Using Femtosecond X-ray Diffraction and Spectroscopy

PubMed Central

Kern, Jan; Tran, Rosalie; Alonso-Mori, Roberto; Koroidov, Sergey; Echols, Nathaniel; Hattne, Johan; Ibrahim, Mohamed; Gul, Sheraz; Laksmono, Hartawan; Sierra, Raymond G.; Gildea, Richard J.; Han, Guangye; Hellmich, Julia; Lassalle-Kaiser, Benedikt; Chatterjee, Ruchira; Brewster, Aaron S.; Stan, Claudiu A.; Glöckner, Carina; Lampe, Alyssa; DiFiore, Dörte; Milathianaki, Despina; Fry, Alan R.; Seibert, M. Marvin; Koglin, Jason E.; Gallo, Erik; Uhlig, Jens; Sokaras, Dimosthenis; Weng, Tsu-Chien; Zwart, Petrus H.; Skinner, David E.; Bogan, Michael J.; Messerschmidt, Marc; Glatzel, Pieter; Williams, Garth J.; Boutet, Sébastien; Adams, Paul D.; Zouni, Athina; Messinger, Johannes; Sauter, Nicholas K.; Bergmann, Uwe; Yano, Junko; Yachandra, Vittal K.

2014-01-01

The dioxygen we breathe is formed from water by its light-induced oxidation in photosystem II. O2 formation takes place at a catalytic manganese cluster within milliseconds after the photosystem II reaction center is excited by three single-turnover flashes. Here we present combined X-ray emission spectra and diffraction data of 2 flash (2F) and 3 flash (3F) photosystem II samples, and of a transient 3F′ state (250 μs after the third flash), collected under functional conditions using an X-ray free electron laser. The spectra show that the initial O-O bond formation, coupled to Mn-reduction, does not yet occur within 250 μs after the third flash. Diffraction data of all states studied exhibit an anomalous scattering signal from Mn but show no significant structural changes at the present resolution of 4.5 Å. This study represents the initial frames in a molecular movie of the structural changes during the catalytic reaction in photosystem II. PMID:25006873

Taking snapshots of photosynthetic water oxidation using femtosecond X-ray diffraction and spectroscopy

NASA Astrophysics Data System (ADS)

Kern, Jan; Tran, Rosalie; Alonso-Mori, Roberto; Koroidov, Sergey; Echols, Nathaniel; Hattne, Johan; Ibrahim, Mohamed; Gul, Sheraz; Laksmono, Hartawan; Sierra, Raymond G.; Gildea, Richard J.; Han, Guangye; Hellmich, Julia; Lassalle-Kaiser, Benedikt; Chatterjee, Ruchira; Brewster, Aaron S.; Stan, Claudiu A.; Glöckner, Carina; Lampe, Alyssa; Difiore, Dörte; Milathianaki, Despina; Fry, Alan R.; Seibert, M. Marvin; Koglin, Jason E.; Gallo, Erik; Uhlig, Jens; Sokaras, Dimosthenis; Weng, Tsu-Chien; Zwart, Petrus H.; Skinner, David E.; Bogan, Michael J.; Messerschmidt, Marc; Glatzel, Pieter; Williams, Garth J.; Boutet, Sébastien; Adams, Paul D.; Zouni, Athina; Messinger, Johannes; Sauter, Nicholas K.; Bergmann, Uwe; Yano, Junko; Yachandra, Vittal K.

2014-07-01

The dioxygen we breathe is formed by light-induced oxidation of water in photosystem II. O2 formation takes place at a catalytic manganese cluster within milliseconds after the photosystem II reaction centre is excited by three single-turnover flashes. Here we present combined X-ray emission spectra and diffraction data of 2-flash (2F) and 3-flash (3F) photosystem II samples, and of a transient 3F’ state (250 μs after the third flash), collected under functional conditions using an X-ray free electron laser. The spectra show that the initial O-O bond formation, coupled to Mn reduction, does not yet occur within 250 μs after the third flash. Diffraction data of all states studied exhibit an anomalous scattering signal from Mn but show no significant structural changes at the present resolution of 4.5 Å. This study represents the initial frames in a molecular movie of the structural changes during the catalytic reaction in photosystem II.

Bright half-cycle optical radiation from relativistic wavebreaking

NASA Astrophysics Data System (ADS)

Miao, Bo; Goers, Andy; Hine, George; Feder, Linus; Salehi, Fatholah; Wahlstrand, Jared; Milchberg, Howard

2015-11-01

Wavebreaking injection of electrons into relativistic plasma wakes generated in near-critical density hydrogen plasmas by sub-terawatt laser pulses is observed to generate an extremely energetic and ultra-broadband radiation flash. The flash is coherent, with a bandwidth of Δλ / λ ~ 0 . 7 consistent with half-cycle optical emission of duration ~ 1 fs from violent unidirectional acceleration of electrons to light speed from rest over a distance much less than the radiated wavelength. We studied the temporal duration and coherence of the flash by interfering it in the frequency domain with a well-characterized Xe supercontinuum pulse. Fringes across the full flash spectrum were observed with high visibility, and the extracted flash spectral phase supports it being a nearly transform-limited pulse. To our knowledge, this is the first evidence of bright half-cycle optical emission. This research is supported by the Defense Threat Reduction Agency, the US Department of Energy, and the Air Force Office of Scientific Research.

Deep Space Detection of Oriented Ice Crystals

NASA Astrophysics Data System (ADS)

Marshak, A.; Varnai, T.; Kostinski, A. B.

2017-12-01

The deep space climate observatory (DSCOVR) spacecraft resides at the first Lagrangian point about one million miles from Earth. A polychromatic imaging camera onboard delivers nearly hourly observations of the entire sun-lit face of the Earth. Many images contain unexpected bright flashes of light over both ocean and land. We constructed a yearlong time series of flash latitudes, scattering angles and oxygen absorption to demonstrate conclusively that the flashes over land are specular reflections off tiny ice crystals floating in the air nearly horizontally. Such deep space detection of tropospheric ice can be used to constrain the likelihood of oriented crystals and their contribution to Earth albedo.

Synchronizing A Stroboscope With A Video Camera

NASA Technical Reports Server (NTRS)

Rhodes, David B.; Franke, John M.; Jones, Stephen B.; Dismond, Harriet R.

1993-01-01

Circuit synchronizes flash of light from stroboscope with frame and field periods of video camera. Sync stripper sends vertical-synchronization signal to delay generator, which generates trigger signal. Flashlamp power supply accepts delayed trigger signal and sends pulse of power to flash lamp. Designed for use in making short-exposure images that "freeze" flow in wind tunnel. Also used for making longer-exposure images obtained by use of continuous intense illumination.

Fabrication and luminescent properties of La2O2S:Eu3+ translucent ceramic by pressureless reaction sintering

NASA Astrophysics Data System (ADS)

Lian, Jingbao; Wang, Bingxin; Liang, Ping; Liu, Feng; Wang, Xuejiao

2014-04-01

La2O2S:Eu3+ translucent ceramic (LOS:Eu) was fabricated by pressureless reaction sintering method. It is found that the (La, Eu)2(OH)4SO4ṡ2H2O precursor is synthesized by co-precipitation using commercially available La(NO3)3, Eu(NO3)3, (NH4)2SO4 and NH3ṡH2O as the starting materials. And this precursor can be converted into pure La2O2SO4:Eu3+ phosphor by calcination at 800 °C for 1 h in air, which is composed of a few small needle agglomerated particles. Then the La2O2SO4:Eu3+ phosphor compact can be sintered into the LOS:Eu at 1500 °C for 2 h in the hybrid atmosphere of flowing hydrogen and argon. Under 387 nm UV light excitation, the LOS:Eu reveals a red light emission at 628 nm as the most prominent peak, which corresponds to the 5D0 → 7F2 transition of Eu3+ ions.

Back-irradiation photonic sintering for defect-free high-conductivity metal patterns on transparent plastic

NASA Astrophysics Data System (ADS)

Kwak, Ji Hye; Chun, Su Jin; Shon, Chae-Hwa; Jung, Sunshin

2018-04-01

Photonic sintering has attracted considerable attention for printed electronics. It irradiates high-intensity light onto the front surface of metal nanoparticle patterns, which often causes defects such as delamination, cavities, and cracks in the patterns. Here, a back-irradiation photonic sintering method is developed for obtaining defect-free high-conductivity metal patterns on a transparent plastic substrate, through which high-intensity light is irradiated onto the back surface of the patterns for a few milliseconds. Ag patterns back-irradiated with ˜10.0 J cm-2 are defect-free in contrast to front-irradiated patterns and exhibited an electrical conductivity of ˜2.3 × 107 S m-1. Furthermore, real-time high-speed observation reveals that the mechanisms that generate defects in the front-irradiated patterns and prevent defects in the back-irradiated patterns are closely related to vapor trapping. In contrast to the latter, in the former, vapor is trapped and delaminates the patterns from the substrate because the front of the patterns acts as a barrier to vapor venting.

Comparison of two methods of visual magnification for removal of adhesive flash during bracket placement using two types of orthodontic bonding agents

PubMed Central

Alencar, Estefania Queiroga de Santana e; Nobrega, Maria de Lourdes Martins; Dametto, Fabio Roberto; dos Santos, Patrícia Bittencourt Dutra; Pinheiro, Fabio Henrique de Sá Leitão

2016-01-01

ABSTRACT Objective: This study aimed to evaluate the effectiveness of two methods of visual magnification (operating microscope and light head magnifying glass) for removal of composite flash around orthodontic metal brackets. Material and Methods: Brackets were bonded in the center of the clinical crown of sixty well-preserved human premolars. Half of the sample was bonded with conventional Transbond XT (3M Unitek TM, USA), whereas the other half was bonded with Transbond TM Plus Color Change (3M Unitek TM, USA). For each type of composite, the choice of method to remove the flash was determined by randomly distributing the teeth into the following subgroups: A (removal by naked eye, n = 10), B (removal with the aid of light head magnifying glass, under 4x magnification, n = 10), and C (removal with the aid of an operating microscope, under 40x magnification, n = 10). Brackets were debonded and teeth taken to a scanning electron microscope (SS-x-550, Shimadzu, Japan) for visualization of their buccal surface. Quantification of composite flash was performed with Image Pro Plus software, and values were compared by Kruskal-Wallis test and Dunn’s post-hoc test at 5% significance level. Results: Removal of pigmented orthodontic adhesive with the aid of light head magnifying glass proved, in general, to be advantageous in comparison to all other methods. Conclusion: There was no advantage in using Transbond TM Plus Color Change alone. Further studies are necessary to draw a more definitive conclusion in regards to the benefits of using an operating microscope. PMID:28125139

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

Manufacture of a UO2-Based Nuclear Fuel with Improved Thermal Conductivity with the Addition of BeO

NASA Astrophysics Data System (ADS)

Garcia, Chad B.; Brito, Ryan A.; Ortega, Luis H.; Malone, James P.; McDeavitt, Sean M.

2017-12-01

The low thermal conductivity of oxide nuclear fuels is a performance-limiting parameter. Enhancing this property may provide a contribution toward establishing accident-tolerant fuel forms. In this study, the thermal conductivity of UO2 was increased through the fabrication of ceramic-ceramic composite forms with UO2 containing a continuous BeO matrix. Fuel with a higher thermal conductivity will have reduced thermal gradients and lower centerline temperatures in the fuel pin. Lower operational temperatures will reduce fission gas release and reduce fuel restructuring. Additions of BeO were made to UO2 fuel pellets in 2.5, 5, 7.5, and 10 vol pct concentrations with the goals of establishing reliable lab-scale processing procedures, minimizing porosity, and maximizing thermal conductivity. The microstructure was characterized with electron probe microanalysis, and the thermal properties were assessed by light flash analysis and differential scanning calorimetry. Reliable, high-density samples were prepared using compaction pressure between 200 and 225 MPa and sintering times between 4 and 6 hours. It was found that the thermal conductivity of UO2 improved approximately 10 pct for each 1 vol pct BeO added over the measured temperature range 298.15 K to 523.15 K (25 °C to 250 °C) with the maximum observed improvement being ˜ 100 pct, or doubled, at 10 vol pct BeO.

Scannerless loss modulated flash color range imaging

DOEpatents

Sandusky, John V [Albuquerque, NM; Pitts, Todd Alan [Rio Rancho, NM

2008-09-02

Scannerless loss modulated flash color range imaging methods and apparatus are disclosed for producing three dimensional (3D) images of a target within a scene. Apparatus and methods according to the present invention comprise a light source providing at least three wavelengths (passbands) of illumination that are each loss modulated, phase delayed and simultaneously directed to illuminate the target. Phase delayed light backscattered from the target is spectrally filtered, demodulated and imaged by a planar detector array. Images of the intensity distributions for the selected wavelengths are obtained under modulated and unmodulated (dc) illumination of the target, and the information contained in the images combined to produce a 3D image of the target.

Scannerless loss modulated flash color range imaging

DOEpatents

Sandusky, John V [Albuquerque, NM; Pitts, Todd Alan [Rio Rancho, NM

2009-02-24

Scannerless loss modulated flash color range imaging methods and apparatus are disclosed for producing three dimensional (3D) images of a target within a scene. Apparatus and methods according to the present invention comprise a light source providing at least three wavelengths (passbands) of illumination that are each loss modulated, phase delayed and simultaneously directed to illuminate the target. Phase delayed light backscattered from the target is spectrally filtered, demodulated and imaged by a planar detector array. Images of the intensity distributions for the selected wavelengths are obtained under modulated and unmodulated (dc) illumination of the target, and the information contained in the images combined to produce a 3D image of the target.

The evolution of adult light emission color in North American fireflies.

PubMed

Hall, David W; Sander, Sarah E; Pallansch, Jennifer C; Stanger-Hall, Kathrin F

2016-09-01

Firefly species (Lampyridae) vary in the color of their adult bioluminescence. It has been hypothesized that color is selected to enhance detection by conspecifics. One mechanism to improve visibility of the signal is to increase contrast against ambient light. High contrast implies that fireflies active early in the evening will emit yellower luminescence to contrast against ambient light reflected from green vegetation, especially in habitats with high vegetation cover. Another mechanism to improve visibility is to use reflection off the background to enhance the light signal. Reflectance predicts that sedentary females will produce greener light to maximize reflection off the green vegetation on which they signal. To test these predictions, we recorded over 7500 light emission spectra and determined peak emission wavelength for 675 males, representing 24 species, at 57 field sites across the Eastern United States. We found support for both hypotheses: males active early in more vegetated habitats produced yellower flashes in comparison to later-active males with greener flashes. Further, in two of the eight species with female data, female light emissions were significantly greener as compared to males. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Integrated smartphone imaging of quantum dot photoluminescence and Förster resonance energy transfer

NASA Astrophysics Data System (ADS)

Petryayeva, Eleonora; Algar, W. Russ

2015-06-01

Smartphones and other mobile devices are emerging as promising analytical platforms for point-of-care diagnostics, particularly when combined with nanotechnology. For example, we have shown that the optical properties of semiconductor quantum dots (QDs) are well suited to photoluminescence (PL) detection with a smartphone camera. However, this previous work has utilized an external excitation source for interrogation of QD PL. In this proceeding, we demonstrate that the white-light LED photographic flashes built into smartphones can be optically filtered to yield blue light suitable for excitation of QD PL. Measurements were made by recording video with filtered flash illumination and averaging the frames of the video to obtain images with good signal-to-background ratios. These images permitted detection of green-emitting and red-emitting QDs at levels comparable to those possible with excitation using an external long-wave UV lamp. The optical properties of QDs proved to be uniquely suited to smartphone PL imaging, exhibiting emission that was 1-2 orders magnitude brighter than that of common fluorescent dyes under the same conditions. Excitation with the smartphone flash was also suitable for imaging of FRET between green-emitting QD donors and Alexa Fluor 555 (A555) fluorescent dye acceptors. No significant difference in FRET imaging capability was observed between excitation with the smartphone flash and a long-wave UV lamp. Although the smartphone flash did have some disadvantages compared to an external UV lamp, these disadvantages are potentially offset by the benefit of having excitation and detection integrated into the smartphone.

Book of Abstracts, 1983 IEEE International Symposium on Applications of Ferroelectrics (ISAF).

DTIC Science & Technology

1984-05-31

adverse internal stresses develop which can contribute to the a31 coefficient. To lower the a31 coefficient the polyurethane is foamed , in addition to...light beams. Since the grating shift depends on the recording mechanism, measurements of the energy transfer can also give additional information on the... addition of Mn ( 1-2 ,ol %) to complete the sintering and decrease the dielectric loss at microwave frequnecy. The sintering w=s madc at 1500W-1600 C

Work Function and Conductivity of Inkjet-Printed Silver Layers: Effect of Inks and Post-treatments

NASA Astrophysics Data System (ADS)

Mitra, Dana; Mitra, Kalyan Yoti; Dzhagan, Volodymyr; Pillai, Nikhil; Zahn, Dietrich R. T.; Baumann, Reinhard R.

2018-03-01

The electronic properties of a printed layer are influenced by a number of factors, including the nature of the ink (nanoparticle- or solution-based), ink composition (solvents, additives, concentration), and post-treatment technologies, especially sintering. One of the major challenges in the field of printed electronics is achieving the desired performance, for example, in terms of conductivity, resistivity, or work function (WF). This work investigates the dependence of sheet resistance and WF on various sintering methodologies. Four different silver nanoparticle inks were inkjet-printed on a flexible polymeric foil and post-treated by thermal sintering (in an oven) or novel sintering processes using infrared or intense pulsed light. The surfaces of the printed and sintered layers were investigated optically, and various inhomogeneities in the layer surface were observed, varying from a smooth to a highly rough appearance with ring-shaped drying structures. An analysis of the sheet resistance revealed notable variation among the various inks and sintering methodologies used. Here, for the very first time, WF is measured and evaluated as a function of sintering methodology and silver ink, and the respective layer formation characteristics realized with the inkjet printing technology. The WF values obtained by ultraviolet photoemission show a similar spread and allow unambiguous trends to be tracked with respect to the type of ink and sintering method used. The values of the WF obtained range from 3.7 eV to 4.3 eV, approaching the reported bulk values of 4.3-4.7 eV. The various silver inks resulted in different WFs when the same sintering method was used, while the same silver ink resulted in different WFs when various sintering methods were applied. Therefore, it is believed that the WF can be tuned over a broad range in a controlled manner to satisfy electronic device requirements.

Temperature, Crystalline Phase and Influence of Substrate Properties in Intense Pulsed Light Sintering of Copper Sulfide Nanoparticle Thin Films.

PubMed

Dexter, Michael; Gao, Zhongwei; Bansal, Shalu; Chang, Chih-Hung; Malhotra, Rajiv

2018-02-02

Intense Pulsed Light sintering (IPL) uses pulsed, visible light to sinter nanoparticles (NPs) into films used in functional devices. While IPL of chalcogenide NPs is demonstrated, there is limited work on prediction of crystalline phase of the film and the impact of optical properties of the substrate. Here we characterize and model the evolution of film temperature and crystalline phase during IPL of chalcogenide copper sulfide NP films on glass. Recrystallization of the film to crystalline covellite and digenite phases occurs at 126 °C and 155 °C respectively within 2-7 seconds. Post-IPL films exhibit p-type behavior, lower resistivity (~10 -3 -10 -4  Ω-cm), similar visible transmission and lower near-infrared transmission as compared to the as-deposited film. A thermal model is experimentally validated, and extended by combining it with a thermodynamic approach for crystal phase prediction and via incorporating the influence of film transmittivity and optical properties of the substrate on heating during IPL. The model is used to show the need to a-priori control IPL parameters to concurrently account for both the thermal and optical properties of the film and substrate in order to obtain a desired crystalline phase during IPL of such thin films on paper and polycarbonate substrates.

Timing in a FLASH

NASA Astrophysics Data System (ADS)

Hoek, M.; Cardinali, M.; Corell, O.; Dickescheid, M.; Ferretti B., M. I.; Lauth, W.; Schlimme, B. S.; Sfienti, C.; Thiel, M.

2017-12-01

A prototype detector, called FLASH (Fast Light Acquiring Start Hodoscope), was built to provide precise Time-of-Flight (TOF) measurements and reference timestamps for detector setups at external beam lines. Radiator bars, made of synthetic fused silica, were coupled to a fast MCP-PMT with 64 channels and read out with custom electronics using Time-over-Threshold (TOT) for signal characterization. The TRB3 system, a high-precision TDC implemented in an FPGA, was used as data acquisition system. The performance of a system consisting of two FLASH units was investigated at a dedicated test experiment at the Mainz Microtron (MAMI) accelerator using its 855 MeV electron beam. The TOT measurement enabled time walk corrections and an overall TOF resolution of ∼70 ps could be achieved which translates into a resolution of ∼50 ps per FLASH unit. The intrinsic resolution of the frontend electronics including the TDC was measured to be less than 25 ps.

Flash LIDAR Emulator for HIL Simulation

NASA Technical Reports Server (NTRS)

Brewster, Paul F.

2010-01-01

NASA's Autonomous Landing and Hazard Avoidance Technology (ALHAT) project is building a system for detecting hazards and automatically landing controlled vehicles safely anywhere on the Moon. The Flash Light Detection And Ranging (LIDAR) sensor is used to create on-the-fly a 3D map of the unknown terrain for hazard detection. As part of the ALHAT project, a hardware-in-the-loop (HIL) simulation testbed was developed to test the data processing, guidance, and navigation algorithms in real-time to prove their feasibility for flight. Replacing the Flash LIDAR camera with an emulator in the testbed provided a cheaper, safer, more feasible way to test the algorithms in a controlled environment. This emulator must have the same hardware interfaces as the LIDAR camera, have the same performance characteristics, and produce images similar in quality to the camera. This presentation describes the issues involved and the techniques used to create a real-time flash LIDAR emulator to support HIL simulation.

A light writable microfluidic "flash memory": optically addressed actuator array with latched operation for microfluidic applications.

PubMed

Hua, Zhishan; Pal, Rohit; Srivannavit, Onnop; Burns, Mark A; Gulari, Erdogan

2008-03-01

This paper presents a novel optically addressed microactuator array (microfluidic "flash memory") with latched operation. Analogous to the address-data bus mediated memory address protocol in electronics, the microactuator array consists of individual phase-change based actuators addressed by localized heating through focused light patterns (address bus), which can be provided by a modified projector or high power laser pointer. A common pressure manifold (data bus) for the entire array is used to generate large deflections of the phase change actuators in the molten phase. The use of phase change material as the working media enables latched operation of the actuator array. After the initial light "writing" during which the phase is temporarily changed to molten, the actuated status is self-maintained by the solid phase of the actuator without power and pressure inputs. The microfluidic flash memory can be re-configured by a new light illumination pattern and common pressure signal. The proposed approach can achieve actuation of arbitrary units in a large-scale array without the need for complex external equipment such as solenoid valves and electrical modules, which leads to significantly simplified system implementation and compact system size. The proposed work therefore provides a flexible, energy-efficient, and low cost multiplexing solution for microfluidic applications based on physical displacements. As an example, the use of the latched microactuator array as "normally closed" or "normally open" microvalves is demonstrated. The phase-change wax is fully encapsulated and thus immune from contamination issues in fluidic environments.

Converting acoustic energy into useful other energy forms

DOEpatents

Putterman, Seth J.; Barber, Bradley Paul; Hiller, Robert Anthony; Lofstedt, Ritva Maire Johanna

1997-01-01

Sonoluminescence is an off-equilibrium phenomenon in which the energy of a resonant sound wave in a liquid is highly concentrated so as to generate flashes of light. The conversion of sound to light represents an energy amplification of eleven orders of magnitude. The flashes which occur once per cycle of the audible or ultrasonic sound fields can be comprised of over one million photons and last for less 100 picoseconds. The emission displays a clocklike synchronicity; the jitter in time between consecutive flashes is less than fifty picoseconds. The emission is blue to the eye and has a broadband spectrum increasing from 700 nanometers to 200 nanometers. The peak power is about 100 milliWatts. The initial stage of the energy focusing is effected by the nonlinear oscillations of a gas bubble trapped in the liquid. For sufficiently high drive pressures an imploding shock wave is launched into the gas by the collapsing bubble. The reflection of the shock from its focal point results in high temperatures and pressures. The sonoluminescence light emission can be sustained by sensing a characteristic of the emission and feeding back changes into the driving mechanism. The liquid is in a sealed container and the seeding of the gas bubble is effected by locally heating the liquid after sealing the container. Different energy forms than light can be obtained from the converted acoustic energy. When the gas contains deuterium and tritium there is the feasibility of the other energy form being fusion, namely including the generation of neutrons.

The photochemical cycle of bacteriorhodopsin

NASA Technical Reports Server (NTRS)

Lozier, R. H.; Niederberger, W.

1977-01-01

The reaction cycle of bacteriorhodopsin in the purple membrane isolated from Halobacterium halobium has been studied by optical absorption spectroscopy using low-temperature and flash kinetic techniques. After absorption of light, bacteriorhodopsin passes through at least five distinct intermediates. The temperature and pH dependence of the absorbance changes suggests that branch points and/or reversible steps exist in this cycle. Flash spectroscopy in the presence of a pH-indicating dye shows that the transient release of a proton accompanies the photoreaction cycle. The proton release occurs from the exterior and the uptake is on the cytoplasmic side of the membrane, as required by the function of bacteriorhodopsin as a light-driven proton pump. Proton translocating steps connecting release and uptake are indicated by deuterium isotope effects on the kinetics of the cycle. The rapid decay of a light-induced linear dichroism shows that a chromophore orientation change occurs during the reaction cycle.

Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles

DOEpatents

Benjamin, R.F.

1983-10-18

An apparatus for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously.

Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles

DOEpatents

Benjamin, Robert F.

1987-01-01

An apparatus for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously.

Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles

DOEpatents

Benjamin, R.F.

1987-03-10

An apparatus is disclosed for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously. 3 figs.

Studies on the nature of the primary reactions of photosystem II in photosynthesis. I. The electrochromic 515 nm absorption change as an appropriate indicator for the functional state of the photochemical active centers of system II in DCMY poisoned chloroplasts.

PubMed

Renger, G; Wolff, C

1975-01-01

The field indicating electrochromic 515 nm absorption change has been measured under different excitation conditions in DCMU poisoned chloroplasts in the presence of benzylviologen as electron acceptor. It has been found: 1. The amplitude of the 515 nm absorption change is nearly completely suppressed under repetitive single turnover flash excitation conditions which kinetically block the back reaction around system II (P. Bennoun, Biochim. Biophys. Acta 216, 357 [1970]). 2. The amplitude of the 515 nm absorption change measured under repetitive single turnover flash excitation conditions which allow the completion of the back reaction during the dark time between the flashes (measuring light beam switched off) amounts in the presence of 2 mum DCMU nearly 50% of the electrochromic 515 nm amplitude obtained in the absence of DCMU. In DCMU poisoned chloroplasts this amplitude is significantly decreased by hydroxylaminhydrochloride, but nearly doubled in the presence of CDIP+ascorbate. 3. The dependence of the 515 nm amplitude on the time td between the flashes kinetically resembles the back reaction around system ?II. The time course of the back reaction can be fairly described either by a second order reaction or by a two phase exponential kinetics. 4. 1,3-dinitrobenzene (DNE) or alpha-bromo-alpha-benzylmalodinitril (BBMD) reduce the 515 nm amplitude in DCMU poisoned chloroplasts, but seem to influecne only slightly the kinetics of the back reaction. 5. The dependence of the 515 nm amplitude on the flash light intensity (the amplitude normalized to 1 at 100% flash light intensity) is not changed by DNB. Based on these experimental data it has been concluded that in DCMU poisoned chloroplasts the amplitude of the 515 nm absorption change reflects the functional state of photosystem II centers (designated as photoelectric dipole generators II) under suitable excitation conditions. Furthermore, it is inferred that in DCMU poisoned chlorplasts the photoelectric dipole generators II either cooperate (probably as twin-pairs) or exist in two functionally different forms. With respect to BBMD and DNB it is assumed that these agents transform the phtooelectric dipole generators II into powerful nonphotochemical quenchers, which significantly reduce the variable fluorescence in DCMU-poisoned chloroplasts.

Light flash phenomena induced by HzE particles

NASA Technical Reports Server (NTRS)

Mcnulty, P. J.; Pease, V. P.

1980-01-01

Astronauts and Apollo and Skylab missions have reported observing a variety of visual phenomena when their eyes are closed and adapted to darkness. These phenomena have been collectively labelled as light flashes. Visual phenomena which are similar in appearance to those observed in space have been demonstrated at the number of accelerator facilities by expressing the eyes of human subjects to beams of various types of radiation. In some laboratory experiments Cerenkov radiation was found to be the basis for the flashes observed while in other experiments Cerenkov radiation could apparently be ruled out. Experiments that differentiate between Cerenkov radiation and other possible mechanisms for inducing visual phenomena was then compared. The phenomena obtained in the presence and absence of Cerenkov radiation were designed and conducted. A new mechanism proposed to explain the visual phenomena observed by Skylab astronauts as they passed through the South Atlantic Anomaly, namely nuclear interactions in and near the sensitive layer of the retina, is covered. Also some studies to search for similar transient effects of space radiation on sensors and microcomputer memories are described.

Dissecting a Light Echo

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] Click on image for audio animation

This animation illustrates how a light echo works, and how an optical illusion of material moving outward is created.

A light echo occurs when a star explodes, acting like a cosmic flashbulb. The light from this explosion zips through nearby dust clumps, illuminating and heating them up slightly. This brief period of warming causes them to glow in infrared, like a chain of Christmas bulbs lighting up one by one.

The animation starts by showing the explosion of a star, which results in a flash of light that moves outward in all directions. The direction of our line of sight from Earth is indicated by the blue arrow.

When the light flash reaches surrounding dust, shown here as three dark clouds, the dust is heated up, creating infrared light that begins to travel toward Earth (indicated by the red arrows). Dust closest to the explosion lights up first, while the explosion's shock wave takes longer to reach more distant material. This results in light from different parts of the cloud reaching Earth at different times, creating the illusion of motion over time.

As the animation shows, the inclination of the cloud toward our line of sight can result in the material seeming to move both away from and toward the central star.

Apollo-Soyuz pamphlet no. 6: Cosmic ray dosage. [experimental designiradiation hazards and dosage

NASA Technical Reports Server (NTRS)

Page, L. W.; From, T. P.

1977-01-01

The radiation hazard inside spacecraft is discussed with emphasis on its effects on the crew, biological specimens, and spacecraft instruments. The problem of light flash sensations in the eyes of astronauts is addressed and experiment MA-106 is described. In this experiment, light flashes seen by blindfolded astronauts were counted and high energy cosmic ray intensity in the command module cabin were measured. The damage caused by cosmic ray hits on small living organisms was investigated in the Biostack 3 experiment (MA-107). Individual cosmic rays were tracked through layers of bacterial spores, small seeds, and eggs interleaved with layers of AgCl-crystal wafers, special plastic, and special photographic film that registered each cosmic ray particle passed.

Lunar impact flashes - tracing the NEO size distribution

NASA Astrophysics Data System (ADS)

Avdellidou, Chrysa; Koschny, Detlef; NELIOTA Team

2017-10-01

Almost 20 years ago, we started to monitor the lunar surface with small telescopes to detect light flashes resulting from the hypervelocity collisions of meteoroids. The initial purpose was to understand the flux of impactors on Earth. The estimation of the flux of near Earth Objects (NEOs) is important not only for the protection of the human civilisation (meter-sized, see Chelyabinsk event in 2013), but also for the protection of the space assets (cm-sized objects). Apart from the NEO flux, the lunar surface helps the study of the impact events per se. The European Space Agency (ESA) is directing and funding lunar observations at 1.2 m Kryoneri telescope in Peloponnese, Greece. This telescope is equipped with a dichroic beam-splitter that directs the light onto two sCMOS cameras, that observe in visible and infrared wavelengths, using Rc and Ic Cousin filters respectively. Currently it is the largest telescope in the world that performs dedicated lunar impact flashes observations. We present the first flash observations in two bands, allowing us to measure flash temperatures for the first time. We find that the temperatures have a range that agrees with the theoretical approaches. Since the temperature can now be calculated, we have a more accurate estimation of the impactor’s mass and the size of the radiated ejecta plume.Having the Moon as a large-scale laboratory, new horizons are set towards the understanding of the nature of impacts, the impactor's material type and the energy partitioning, that is a constant puzzle in impact studies. This can now happen as more impact parameters can be determined and combined, such as the impactor’s mass and speed, flash luminosity, radiating volume, crater size when applicable etc. Future statistics can determine the different lunar regolith properties at different impact sites, especially during a meteoroid stream where the impactors share a common origin and possibly composition.

Effects of particle size and forming pressure on pore properties of Fe-Cr-Al porous metal by pressureless sintering

NASA Astrophysics Data System (ADS)

Koo, Bon-Uk; Yi, Yujeong; Lee, Minjeong; Kim, Byoung-Kee

2017-03-01

With increased hydrogen consumption in ammonia production, refining and synthesis, fuel cells and vehicle industries, development of the material components related to hydrogen production is becoming an important factor in industry growth. Porous metals for fabrication of hydrogen are commonly known for their relative excellence in terms of large area, lightness, lower heat capacity, high toughness, and permeability. Fe-Cr-Al alloys not only have high corrosion resistance, heat resistance, and chemical stability but also ductility, excellent mechanical properties. In order to control powder size and sintering temperature effects of Fe-Cr-Al porous metal fabrication, Fe-Cr-Al powder was classified into 25-35 μm, 35-45 μm, 45-75 μm using an auto shaking sieve machine and then classified Fe-Cr-Al powders were pressed into disk shapes using a uniaxial press machine and CIP. The pelletized Fe-Cr-Al specimens were sintered at various temperatures in high vacuum. Properties such as pore size, porosity, and air permeability were evaluated using perm-porosimetry. Microstructure and phase changes were observed with SEM and XRD. Porosity and relative density were proportionated to increasing sintering temperature. With sufficient sintering at increasing temperatures, the pore size is expected to be gradually reduced. Porosity decreased with increasing sintering temperature and gradually increased necking of the powder.

Diversionary device history and revolutionary advancements.

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

Cooper, Paul W.; Grubelich, Mark Charles

Diversionary devices also known as flash bangs or stun grenades were first employed about three decades ago. These devices produce a loud bang accompanied by a brilliant flash of light and are employed to temporarily distract or disorient an adversary by overwhelming their visual and auditory senses in order to gain a tactical advantage. Early devices that where employed had numerous shortcomings. Over time, many of these deficiencies were identified and corrected. This evolutionary process led to today's modern diversionary devices. These present-day conventional diversionary devices have undergone evolutionary changes but operate in the same manner as their predecessors. Inmore » order to produce the loud bang and brilliant flash of light, a flash powder mixture, usually a combination of potassium perchlorate and aluminum powder is ignited to produce an explosion. In essence these diversionary devices are small pyrotechnic bombs that produce a high point-source pressure in order to achieve the desired far-field effect. This high point-source pressure can make these devices a hazard to the operator, adversaries and hostages even though they are intended for 'less than lethal' roles. A revolutionary diversionary device has been developed that eliminates this high point-source pressure problem and eliminates the need for the hazardous pyrotechnic flash powder composition. This new diversionary device employs a fuel charge that is expelled and ignited in the atmosphere. This process is similar to a fuel air or thermobaric explosion, except that it is a deflagration, not a detonation, thereby reducing the overpressure hazard. This technology reduces the hazard associated with diversionary devices to all involved with their manufacture, transport and use. An overview of the history of diversionary device development and developments at Sandia National Laboratories will be presented.« less

Computer controlled fluorometer device and method of operating same

DOEpatents

Kolber, Z.; Falkowski, P.

1990-07-17

A computer controlled fluorometer device and method of operating same, said device being made to include a pump flash source and a probe flash source and one or more sample chambers in combination with a light condenser lens system and associated filters and reflectors and collimators, as well as signal conditioning and monitoring means and a programmable computer means and a software programmable source of background irradiance that is operable according to the method of the invention to rapidly, efficiently and accurately measure photosynthetic activity by precisely monitoring and recording changes in fluorescence yield produced by a controlled series of predetermined cycles of probe and pump flashes from the respective probe and pump sources that are controlled by the computer means. 13 figs.

Computer controlled fluorometer device and method of operating same

DOEpatents

Kolber, Zbigniew; Falkowski, Paul

1990-01-01

A computer controlled fluorometer device and method of operating same, said device being made to include a pump flash source and a probe flash source and one or more sample chambers in combination with a light condenser lens system and associated filters and reflectors and collimators, as well as signal conditioning and monitoring means and a programmable computer means and a software programmable source of background irradiance that is operable according to the method of the invention to rapidly, efficiently and accurately measure photosynthetic activity by precisely monitoring and recording changes in fluorescence yield produced by a controlled series of predetermined cycles of probe and pump flashes from the respective probe and pump sources that are controlled by the computer means.

Influence of Tile Geometry on the Dynamic Fracture of Silicon Carbide (SiC)

DTIC Science & Technology

2014-03-01

velocity was 440 ± 5.6 m/s. Two flash x-rays were set up above the shot line in front of the light gas gun to measure the velocity of the projectile...long, high-density polyurethane foam sabot. A sabot stripper on the muzzle of the gun disengaged the sabot from the sphere prior to velocity...the masses were consistent to achieve a constant velocity. The projectile traveled from the gun, through a break screen which triggered two flash x

Photorefraction of the Eye

ERIC Educational Resources Information Center

Colicchia, Giuseppe; Wiesner, Hartmut; Zollman, Dean

2015-01-01

Photorefraction is a method to easily estimate the refractive state of the eye. The principle of photorefraction involves projecting light into the eye during flash photography and then examining the paths of light that emerge from the pupil after scattering on the back portion of the interior of the eyeball (fundus). We will explain the optical…

Retinal detachment

MedlinePlus

... eye, including the retina ( ophthalmoscopy ) Checking eyeglass prescription ( refraction test ) Checking color vision Checking the smallest letters ... of the first symptoms of new flashes of light and floaters. Prevention Use protective eye wear to ...

Cosmic ray effects on the eyes of rats flown on Cosmos no. 782, Experiment K-007

NASA Technical Reports Server (NTRS)

Philpott, D. E.; Corbett, R.; Turnbill, C.; Harrison, G.; Leaffer, D.; Black, S.; Sapp, W.; Klein, G.; Savik, L. F.

1978-01-01

A study was undertaken to determine if, and to what extent, pathological damage results from high-energy particles (HZE) transversing the eye. Light flashes experienced by space travellers indicate that HZE do indeed pass through and activate the retina, but whether actual biological damage occurs has not been investigated thoroughly. Thus, autopsies were performed on the eyes of rats which has been flown in Cosmos 782 satellite for 19.5 days. Comparisons with a control sample subjected to 1000 rads of Ar and Ne radiation show that pathological damage, when it occurs, affects the nucleus of the retina; simple light flashes are not thought to indicate a pathology, and result from activation of (but not damage to) the retina's outer segments.

Experimental observation of the luminescence flash at the collapse phase of a bubble produced by pulsed discharge in water

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

Huang, Yifan; Zhang, Liancheng; Zhu, Xinlei

2015-11-02

This letter presents an experimental observation of luminescence flash at the collapse phase of an oscillating bubble produced by a pulsed discharge in water. According to the high speed records, the flash lasts around tens of microseconds, which is much longer than the lifetime of laser and ultrasound induced luminescence flashes in nanoseconds and picoseconds, respectively. The pulse width of temperature waveform and minimum radius calculated at the collapse phase also show that the thermodynamic and dynamic signatures of the bubbles in this work are much larger than those of ultrasound and laser induced bubbles both in time and spacemore » scales. However, the peak temperature at the point of collapse is close to the results of ultrasound and laser induced bubbles. This result provides another possibility for accurate emission spectrum measurement other than amplification of the emitted light, such as increasing laser energy or sound energy or substituting water with sulphuric acid.« less

Monte Carlo Radiative Transfer Modeling of Lightning Observed in Galileo Images of Jupiter

NASA Technical Reports Server (NTRS)

Dyudine, U. A.; Ingersoll, Andrew P.

2002-01-01

We study lightning on Jupiter and the clouds illuminated by the lightning using images taken by the Galileo orbiter. The Galileo images have a resolution of 25 km/pixel and axe able to resolve the shape of the single lightning spots in the images, which have full widths at half the maximum intensity in the range of 90-160 km. We compare the measured lightning flash images with simulated images produced by our ED Monte Carlo light-scattering model. The model calculates Monte Carlo scattering of photons in a ED opacity distribution. During each scattering event, light is partially absorbed. The new direction of the photon after scattering is chosen according to a Henyey-Greenstein phase function. An image from each direction is produced by accumulating photons emerging from the cloud in a small range (bins) of emission angles. Lightning bolts are modeled either as points or vertical lines. Our results suggest that some of the observed scattering patterns axe produced in a 3-D cloud rather than in a plane-parallel cloud layer. Lightning is estimated to occur at least as deep as the bottom of the expected water cloud. For the six cases studied, we find that the clouds above the lightning are optically thick (tau > 5). Jovian flashes are more regular and circular than the largest terrestrial flashes observed from space. On Jupiter there is nothing equivalent to the 30-40-km horizontal flashes which axe seen on Earth.

Microfabrics in Siliceous Hotsprings: Yellowstone National Park, Wyoming

NASA Technical Reports Server (NTRS)

Guidry, S. A.; Chafetz, H. S.; Westall, F.

2001-01-01

Microfabrics shed light on the mechanisms governing siliceous sinter precipitation, the profound effects of microorganisms, as well as a conventional facies model for siliceous hotsprings. Additional information is contained in the original extended abstract.

Optical properties of phosphor-in-glass through modification of pore properties for LED packaging

NASA Astrophysics Data System (ADS)

Kim, Sunil; Kim, Hyungsun

2018-01-01

The volume and size of the voids present between the frit and the phosphor particles used before sintering determine the pore properties of the resulting phosphor-in-glass (PIG). The pores formed from the voids influence the path of the incident light, thus changing the optical properties of the PIG. Therefore, the trends observed for the shrinkage and the green and sintered densities of the PIG were investigated using SiO2-B2O3-ZnO-K2O glass frit of four sizes to understand the tendency for the pore size, porosity, and optical properties of PIG. It has been demonstrated that variation in the pore properties according to the particle size influences parameters defining the light scattering phenomenon, such as the scattering angle of the light and the scattering coefficient, as well as the color rendering index, correlated color temperature, and package efficacy. The results obtained for the variation in the optical properties with the frit size can be used as a reference to select the appropriate glass frit size to achieve the required optical properties for a light-emitting diode (LED) package.

Terrestrial glint seen from deep space: Oriented ice crystals detected from the Lagrangian point

NASA Astrophysics Data System (ADS)

Marshak, Alexander; Várnai, Tamás.; Kostinski, Alexander

2017-05-01

The Deep Space Climate Observatory (DSCOVR) spacecraft resides at the first Lagrangian point about one million miles from Earth. A polychromatic imaging camera onboard delivers nearly hourly observations of the entire sunlit face of the Earth. Many images contain unexpected bright flashes of light over both ocean and land. We construct a yearlong time series of flash latitudes, scattering angles, and oxygen absorption to demonstrate conclusively that the flashes over land are specular reflections off tiny ice platelets floating in the air nearly horizontally. Such deep space detection of tropospheric ice can be used to constrain the likelihood of oriented crystals and their contribution to Earth albedo. These glint observations also support proposals for detecting starlight glints off faint companions in our search for habitable exoplanets.

Voltage Dependence of Proton Pumping by Bacteriorhodopsin Mutants with Altered Lifetime of the M Intermediate

PubMed Central

Geibel, Sven; Lörinczi, Èva; Bamberg, Ernst; Friedrich, Thomas

2013-01-01

The light-driven proton pump bacteriorhodopsin (BR) from Halobacterium salinarum is tightly regulated by the [H+] gradient and transmembrane potential. BR exhibits optoelectric properties, since spectral changes during the photocycle are kinetically controlled by voltage, which predestines BR for optical storage or processing devices. BR mutants with prolonged lifetime of the blue-shifted M intermediate would be advantageous, but the optoelectric properties of such mutants are still elusive. Using expression in Xenopus oocytes and two-electrode voltage-clamping, we analyzed photocurrents of BR mutants with kinetically destabilized (F171C, F219L) or stabilized (D96N, D96G) M intermediate in response to green light (to probe H+ pumping) and blue laser flashes (to probe accumulation/decay of M). These mutants have divergent M lifetimes. As for BR-WT, this strictly correlates with the voltage dependence of H+ pumping. BR-F171C and BR-F219L showed photocurrents similar to BR-WT. Yet, BR-F171C showed a weaker voltage dependence of proton pumping. For both mutants, blue laser flashes applied during and after green-light illumination showed reduced M accumulation and shorter M lifetime. In contrast, BR-D96G and BR-D96N exhibited small photocurrents, with nonlinear current-voltage curves, which increased strongly in the presence of azide. Blue laser flashes showed heavy M accumulation and prolonged M lifetime, which accounts for the strongly reduced H+ pumping rate. Hyperpolarizing potentials augmented these effects. The combination of M-stabilizing and -destabilizing mutations in BR-D96G/F171C/F219L (BR-tri) shows that disruption of the primary proton donor Asp-96 is fatal for BR as a proton pump. Mechanistically, M destabilizing mutations cannot compensate for the disruption of Asp-96. Accordingly, BR-tri and BR-D96G photocurrents were similar. However, BR-tri showed negative blue laser flash-induced currents even without actinic green light, indicating that Schiff base deprotonation in BR-tri exists in the dark, in line with previous spectroscopic investigations. Thus, M-stabilizing mutations, including the triple mutation, drastically interfere with electrochemical H+ gradient generation. PMID:24019918

Enhanced Sintering of TiNi Shape Memory Foams under Mg Vapor Atmosphere

NASA Astrophysics Data System (ADS)

Aydoğmuş, Tarik; Bor, Şakir

2012-12-01

TiNi alloy foams are promising candidates for biomaterials to be used as artificial orthopedic implant materials for bone replacement applications in biomedical sector. However, certain problems exist in their processing routes, such as formation of unwanted secondary intermetallic phases leading to brittleness and deterioration of shape memory and superelasticity characteristics; and the contamination during processing resulting in oxides and carbonitrides which affect mechanical properties negatively. Moreover, the eutectic reaction present in Ti-Ni binary system at 1391 K (1118 °C) prevents employment of higher sintering temperatures (and higher mechanical properties) even when equiatomic prealloyed powders are used because of Ni enrichment of TiNi matrix as a result of oxidation. It is essential to prevent oxidation of TiNi powders during processing for high-temperature (>1391 K i.e., 1118 °C) sintering practices. In the current study, magnesium powders were used as space holder material to produce TiNi foams with the porosities in the range of 40 to 65 pct. It has been found that magnesium prevents secondary phase formation and contamination. It also prevents liquid phase formation while enabling employment of higher sintering temperatures by two-step sintering processing: holding the sample at 1373 K (1100 °C) for 30 minutes, and subsequently sintering at temperatures higher than the eutectic temperature, 1391 K (1118 °C). By this procedure, magnesium may allow sintering up to temperatures close to the melting point of TiNi. TiNi foams produced with porosities in the range of 40 to 55 pct were found to be acceptable as implant materials in the light of their favorable mechanical properties.

A new in vivo screening model for posterior spinal bone formation: comparison of ten calcium phosphate ceramic material treatments.

PubMed

Wilson, Clayton E; Kruyt, Moyo C; de Bruijn, Joost D; van Blitterswijk, Clemens A; Oner, F Cumhur; Verbout, Abraham J; Dhert, Wouter J A

2006-01-01

This study presents a new screening model for evaluating the influence of multiple conditions on the initial process of bone formation in the posterior lumbar spine of a large animal. This model uses cages designed for placement on the decorticated transverse process of the goat lumbar spine. Five conduction channels per cage, each be defined by a different material treatment, are open to both the underlying bone and overlying soft tissue. The model was validated in ten adult Dutch milk goats, with each animal implanted with two cages containing a total of ten calcium phosphate material treatments according to a randomized complete block design. The ten calcium phosphate ceramic materials were created through a combination of material chemistry (BCP, TCP, HA), sintering temperature (low, medium, high), calcination and surface roughness treatments. To monitor the bone formation over time, fluorochrome markers were administered at 3, 5 and 7 weeks and the animals were sacrificed at 9 weeks after implantation. Bone formation in the conduction channels was investigated by histology and histomorphometry of non-decalcified sections using traditional light and epifluorescent microscopy. According to both observed and measured bone formation parameters, materials were ranked in order of increasing magnitude as follows: low sintering temperature BCP (rough and smooth) approximately medium sintering temperature BCP approximately = TCP > calcined low sintering temperature HA > non-calcined low sintering temperature HA > high sintering temperature BCP (rough and smooth) > high sintering temperature HA (calcined and non-calcined). These results agree closely with those obtained in previous studies of osteoconduction and bioactivity of ceramics thereby validating the screening model presented in this study.

White light velocity interferometer

DOEpatents

Erskine, D.J.

1999-06-08

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

White light velocity interferometer

DOEpatents

Erskine, David J.

1997-01-01

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

White light velocity interferometer

DOEpatents

Erskine, David J.

1999-01-01

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

White light velocity interferometer

DOEpatents

Erskine, D.J.

1997-06-24

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

Intense pulsed light annealing of copper zinc tin sulfide nanocrystal coatings

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

Williams, Bryce A.; Smeaton, Michelle A.; Holgate, Collin S.

2016-09-15

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

Kinetics and components of the flash photocurrent of isolated retinal rods of the larval salamander, Ambystoma tigrinum.

PubMed Central

Cobbs, W H; Pugh, E N

1987-01-01

1. Membrane currents initiated by intense, 20 microseconds flashes (photocurrents) were recorded from isolated salamander rods by combined extracellular suction electrodes and intracellular tight-seal electrodes either in current or voltage clamp mode. The magnitudes (mean +/- 2 S.E.M.) of the maximal photoresponses recorded by the suction and by the intracellular electrode respectively were 40 +/- 5 pA (n = 18) and 35 +/- 7 mV (n = 8) for current clamp at zero current; 43 +/- 9 pA and 66 +/- 13 (n = 11) pA for voltage clamp at the zero-current holding potential, -24 +/- 3 mV. 2. Photocurrents initiated by flashes isomerizing 0.1% or more of the outer segment's rhodopsin achieved a saturated velocity and were 95% complete in less than 50 ms. The effect of incrementing flash intensity above 0.1% isomerization can be described as a translation of the photocurrent along the time axis towards the origin. Within the interval 0-50 ms the latter two-thirds of the velocity-saturated photocurrent is well described as a single-exponential decay. The decay was much faster in voltage clamp (2.8 +/- 1.2 ms, n = 11) than in current clamp mode (17 +/- 5 ms, n = 17). 3. The initial third of the velocity-saturated photocurrent, occurring over the interval from the flash to the onset of exponential decay, followed about the same time course in current and voltage clamp. The time interval occupied by this initial 'latent' phase decreased with increasing flash intensity and attained an apparent minimum of about 7 ms in response to flashes isomerizing 10% or more of the rhodopsin at ca. 22 degrees C. 4. The hypothesis that the decay of outer segment light-sensitive membrane current is the same in current and voltage clamp was supported by an analysis of the difference between outer segment currents measured successively in the two recording modes. First, the tail of the difference current decayed exponentially with a time constant approximately equal to R x C, where R and C are independently estimated slope resistance and capacitance of the rod. Secondly, the integral of the difference current, when divided by outer segment capacitance, closely approximated the hyperpolarizing light response measured under current clamp. Thus, displacement current accounted for the difference between photocurrents measured in current and voltage clamp.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2832596

33 CFR 207.640 - Sacramento Deep Water Ship Channel Barge Lock and Approach Canals; use, administration, and...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Engineer District, Sacramento, Federal and Courts Building, 650 Capitol Avenue, Sacramento, California. His... green light is flashing, lock is ready for entrance, the vessel may proceed with caution into the lock... or canal. Vessel may enter canal with caution. When the green light is on, vessel may enter canal and...

33 CFR 117.393 - Illinois Waterway.

Code of Federal Regulations, 2010 CFR

2010-07-01

... light to indicate that vessels may pass. (2) When a vessel is approaching and the draw is in the open... remains open until passage is complete. (3) When a vessel is approaching and the draw is in the closed..., flashing amber lights are displayed. (4) When a train approaches the bridge and the draw is in the open...

Cosmic flashing lights

NASA Astrophysics Data System (ADS)

Di Stefano, Rosanne

2018-04-01

Gravitational lensing is becoming increasingly important to the study of distant galaxies and dark matter. Two groups have recently detected transient events emanating from far-away lensed galaxies, apparently due to extreme magnification of individual stars.

SSD Market Overview

NASA Astrophysics Data System (ADS)

Wong, G.

The unparalleled cost and form factor advantages of NAND flash memory has driven 35 mm photographic film, floppy disks and one-inch hard drives to extinction. Due to its compelling price/performance characteristics, NAND Flash memory is now expanding its reach into the once-exclusive domain of hard disk drives and DRAM in the form of Solid State Drives (SSDs). Driven by the proliferation of thin and light mobile devices and the need for near-instantaneous accessing and sharing of content through the cloud, SSDs are expected to become a permanent fixture in the computing infrastructure.

49 CFR Appendix A to Part 234 - Schedule of Civil Penalties 1

Code of Federal Regulations, 2010 CFR

2010-10-01

....219Gate arm lights and light cable 1,000 2,000 234.221Lamp voltage 1,000 2,000 234.223Gate arm 1,000 2,000... 234.251Standby power 5,000 7,500 234.253Flashing light units and lamp voltage 1,000 2,000 234.255Gate....265Timing relays and timing devices 1,000 2,000 234.267Insulation resistance tests, wires in trunking and...

BRDF Calibration of Sintered PTFE in the SWIR

NASA Technical Reports Server (NTRS)

Georgiev, Georgi T.; Butler, James J.

2009-01-01

Satellite instruments operating in the reflective solar wavelength region often require accurate and precise determination of the Bidirectional Reflectance Distribution Function (BRDF) of laboratory-based diffusers used in their pre-flight calibrations and ground-based support of on-orbit remote sensing instruments. The Diffuser Calibration Facility at NASA's Goddard Space Flight Center is a secondary diffuser calibration standard after NEST for over two decades, providing numerous NASA projects with BRDF data in the UV, Visible and the NIR spectral regions. Currently the Diffuser Calibration Facility extended the covered spectral range from 900 nm up to 1.7 microns. The measurements were made using the existing scatterometer by replacing the Si photodiode based receiver with an InGaAs-based one. The BRDF data was recorded at normal incidence and scatter zenith angles from 10 to 60 deg. Tunable coherent light source was setup. Broadband light source application is under development. Gray-scale sintered PTFE samples were used at these first trials, illuminated with P and S polarized incident light. The results are discussed and compared to empirically generated BRDF data from simple model based on 8 deg directional/hemispherical measurements.

Observations of Two Sprite-Producing Storms in Colorado

NASA Technical Reports Server (NTRS)

Lang, Timothy J.; Lyons, Walter A.; Cummer, Steven A.; Fuchs, Brody R.; Dolan, Brenda; Rutledge, Steven A.; Krehbiel, Paul; Rison, William; Stanley, Mark; Ashcraft, Thomas

2016-01-01

Two sprite-producing thunderstorms were observed on 8 and 25 June 2012 in northeastern Colorado by a combination of low-light cameras, a lightning mapping array, polarimetric and Doppler radars, the National Lightning Detection Network, and charge moment change measurements. The 8 June event evolved from a tornadic hailstorm to a larger multicellular system that produced 21 observed positive sprites in 2 h. The majority of sprites occurred during a lull in convective strength, as measured by total flash rate, flash energy, and radar echo volume. Mean flash area spiked multiple times during this period; however, total flash rates still exceeded 60 min(sup 1), and portions of the storm featured a complex anomalous charge structure, with midlevel positive charge near 20degC. The storm produced predominantly positive cloud-to-ground lightning. All sprite-parent flashes occurred on the northeastern flank of the storm, where strong westerly upper level flow was consistent with advection of charged precipitation away from convection, providing a pathway for stratiform lightning. The 25 June event was another multicellular hailstorm with an anomalous charge structure that produced 26 positive sprites in less than 1 h. The sprites again occurred during a convective lull, with relatively weaker reflectivity and lower total flash rate but relatively larger mean flash area. However, all sprite parents occurred in or near convection and tapped charge layers in adjacent anvil cloud. The results demonstrate the sprite production by convective ground strokes in anomalously charged storms and also indicate that sprite production and convective vigor are inversely related in mature storms.

PAIR-DOMINATED GeV-OPTICAL FLASH IN GRB 130427A

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

Vurm, Indrek; Hascoët, Romain; Beloborodov, Andrei M., E-mail: indrek.vurm@gmail.com

2014-07-10

We show that the light curve of the double GeV+optical flash in GRB 130427A is consistent with radiation from the blast wave in a wind-type medium with density parameter A = ρr {sup 2} ∼ 5 × 10{sup 10} g cm{sup –1}. The peak of the flash is emitted by copious e {sup ±} pairs created and heated in the blast wave; our first-principle calculation determines the pair-loading factor and temperature of the shocked plasma. Using detailed radiative transfer simulations, we reconstruct the observed double flash. The optical flash is dominated by synchrotron emission from the thermal plasma behind the forward shock, andmore » the GeV flash is produced via inverse Compton (IC) scattering by the same plasma. The seed photons for IC scattering are dominated by the prompt MeV radiation during the first tens of seconds, and by the optical to X-ray afterglow thereafter. IC cooling of the thermal plasma behind the forward shock reproduces all GeV data from a few seconds to ∼1 day. We find that the blast wave Lorentz factor at the peak of the flash is Γ ≈ 200, and the forward shock magnetization is ε{sub B} ∼ 2 × 10{sup –4}. An additional source is required by the data in the optical and X-ray bands at times >10{sup 2} s; we speculate that this additional source may be a long-lived reverse shock in the explosion ejecta.« less

33 CFR 117.253 - Anacostia River.

Code of Federal Regulations, 2011 CFR

2011-07-01

... traffic lights will flash red, and an audio voice-warning device will announce bridge movement during... condition two board gauges painted white with black figures not less than six inches high to indicate the...

33 CFR 117.253 - Anacostia River.

Code of Federal Regulations, 2010 CFR

2010-07-01

... traffic lights will flash red, and an audio voice-warning device will announce bridge movement during... condition two board gauges painted white with black figures not less than six inches high to indicate the...

Structural properties and gas sensing behavior of sol-gel grown nanostructured zinc oxide

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

Rajyaguru, Bhargav; Gadani, Keval; Kansara, S. B.

2016-05-06

In this communication, we report the results of the studies on structural properties and gas sensing behavior of nanostructured ZnO grown using acetone precursor based modified sol-gel technique. Final product of ZnO was sintered at different temperatures to vary the crystallite size while their structural properties have been studied using X-ray diffraction (XRD) measurement performed at room temperature. XRD results suggest the single phasic nature of all the samples and crystallite size increases from 11.53 to 20.96 nm with increase in sintering temperature. Gas sensing behavior has been studied for acetone gas which indicates that lower sintered samples are moremore » capable to sense the acetone gas and related mechanism has been discussed in the light of crystallite size, crystal boundary density, defect mechanism and possible chemical reaction between gas traces and various oxygen species.« less

2D all-solid state fabric supercapacitor fabricated via an all solution process for use in smart textiles

NASA Astrophysics Data System (ADS)

Jang, Yunseok; Jo, Jeongdai; Woo, Kyoohee; Lee, Seung-Hyun; Kwon, Sin; Kim, Kwang-Young; Kang, Dongwoo

2017-05-01

We propose a method to fabricate a supercapacitor for smart textiles using silver (Ag) nanoparticle (NP) ink, simple spray patterning systems, and intense pulsed light (IPL) sintering systems. The Ag NP current collectors provided as high conductivity as the metal current collectors. The spray patterning technique is useful for fabricating supercapacitors because it is simple, fast, and cheap. IPL systems reduced the sintering temperature of Ag NPs and prevented thermal damage to the textiles during the Ag NP sintering process. The two-dimensional (2D) all-solid state fabric supercapacitor with an interdigitated configuration, developed here, exhibited a specific capacitance of 25.7 F/g and an energy density of 1.5 Wh/kg at a power density of 64.3 W/kg. These results support the utility of our proposed method in the development of energy textiles.

Non-independent quantum bumps in Limulus ventral nerve photoreceptors--a new insight in the light transduction mechanism.

PubMed

Nagy, K

1992-09-14

Single photon-induced transient currents, called quantum bumps were stimulated by short flashes in dark-adapted ventral nerve photoreceptors of Limulus. Flash intensities were set to activate 3 or more bumps. In most cases, current bumps were activated with a constant rate. The frequency of bump occurrence was between 9 and 17 Hz. Results show that consecutive bumps are not independent and that some of them are not activated by a photon. The periodic bump activation indicates a molecular mechanism which quantifies the transmitter release not only by a light quantum, but also by a late phase of the transduction cascade. A model is proposed, in which Ca2+ ions released from intracellular stores transiently block the further Ca2+ release by inositol trisphosphate in an all-or-none manner.

A LED-based phosphorimeter for measurement of microcirculatory oxygen pressure.

PubMed

Guerci, Philippe; Ince, Yasin; Heeman, Paul; Faber, Dirk; Ergin, Bulent; Ince, Can

2017-02-01

Quantitative measurements of microcirculatory and tissue oxygenation are of prime importance in experimental research. The noninvasive phosphorescence quenching method has given further insight into the fundamental mechanisms of oxygen transport to healthy tissues and in models of disease. Phosphorimeters are devices dedicated to the study of phosphorescence quenching. The experimental applications of phosphorimeters range from measuring a specific oxygen partial pressure (Po 2 ) in cellular organelles such as mitochondria, finding values of Po 2 distributed over an organ or capillaries, to measuring microcirculatory Po 2 changes simultaneously in several organ systems. Most of the current phosphorimeters use flash lamps as a light excitation source. However, a major drawback of flash lamps is their inherent plasma glow that persists for tens of microseconds after the primary discharge. This complex distributed excitation pattern generated by the flash lamp can lead to inaccurate Po 2 readings unless a deconvolution analysis is performed. Using light-emitting diode (LED), a rectangular shaped light pulse can be generated that provides a more uniformly distributed excitation signal. This study presents the design and calibration process of an LED-based phosphorimeter (LED-P). The in vitro calibration of the LED-P using palladium(II)-meso-tetra(4-carboxyphenyl)-porphyrin (Pd-TCCP) as a phosphorescent dye is presented. The pH and temperature were altered to assess whether the decay times of the Pd-TCCP measured by the LED-P were significantly influenced. An in vivo validation experiment was undertaken to measure renal cortical Po 2 in a rat subjected to hypoxic ventilation conditions and ischemia/reperfusion. The benefits of using LEDs as a light excitation source are presented. Copyright © 2017 the American Physiological Society.

Using the human eye to image space radiation or the history and status of the light flash phenomena

NASA Astrophysics Data System (ADS)

Fuglesang, C.

2007-10-01

About 80% of people who travel in space experience sudden phosphenes, commonly called light flashes (LF). Although the detailed physiological process is still not known, the LFs are caused by particles in the cosmic radiation field. Indeed, by counting LFs one can even make a crude image of the radiation environment around the Earth. Studies on the space station Mir with the SilEye experiment correlated LFs with charged particles traversing the eye. It was found that a nucleus in the radiation environment has roughly a 1% probability of causing a light flash, whereas the proton's probability is almost three orders of magnitude less. As a function of linear energy transfer (LET), the probability increased with ionization above 10 keV/μm, reaching about 5% at 50 keV/μm. The investigations are continuing on the International Space Station (ISS) with the Alteino/SileEye-3 detector, which is also a precursor to the large Anomalous Long Term Effects on Astronauts (ALTEA) facility. These detectors are also measuring—imaging—the radiation environment inside the ISS, which will be compared to Geant4 simulations from the DESIRE project. To further the understanding of the LF phenomena, a survey among current NASA and ESA astronauts was recently conducted. The LFs are predominantly noticed before sleep and some respondents even thought it disturbed their sleep. The LFs appear white, have elongated shapes, and most interestingly, often come with a sense of motion. Comparing the shapes quoted from space observations with ground experiments done by researchers in the 1970s, it seems likely that some 5-10% of the LFs in space are due to Cherenkov light in the eye. However, the majority is most likely caused by some direct interaction in the retina.

Interactions of Alumina-Based and Magnesia-Based Refractories with Iron Melts and Slags: A Review

NASA Astrophysics Data System (ADS)

Sarkar, R.; Sohn, H. Y.

2018-06-01

A novel flash ironmaking technology (FIT) based on the direct reduction of iron ore concentrate with a reductant gas (such as hydrogen, natural gas, coal gas, or a combination thereof) in a flash furnace is being developed at the University of Utah. This technology which is undergoing large-scale laboratory testing aims at overcoming the limitations of blast furnace ironmaking by bypassing the problematic pelletization/sintering and cokemaking steps.[1-5] Refractory selection is expected to play an important step in the development of FIT and its proposed scale-up. For nominating an appropriate refractory for the FIT, understanding the interactions of candidate refractories with iron/iron oxide and slags under H2/CO/CO2/H2O environments is necessary. This work is undertaken to review the existing literature on the interactions of important refractories with iron melts and relevant slags with an emphasis on two of the most commonly used refractories in ironmaking and steelmaking applications: the alumina-based refractories (used widely in blast furnace operations) and the magnesia-based refractories (used extensively in primary as well as secondary steelmaking). First, a comprehensive review on the interactions of alumina-based refractories with iron melts and slags has been done. Next the existing literature on the interactions of magnesia-based refractories with iron melts and relevant slags has been reviewed. Summaries have been included after each section and sub-section along with comments and critical insights from the authors. Finally, in the concluding remarks the differences in operating conditions between existing iron and steelmaking practices and the novel FIT have been highlighted. On the basis of these differences, it has been argued that the results and conclusions available from previous studies on refractory-metal-slag interactions are of little significance to flash ironmaking. Thus, there exists a need to carry out laboratory experiments for evaluating refractory performance in flash ironmaking under conditions relevant to the current process (FIT).

Monolithic translucent BaMgAl 10O 17:Eu 2+ phosphors for laser-driven solid state lighting

DOE PAGES

Cozzan, Clayton; Brady, Michael J.; O’Dea, Nicholas; ...

2016-10-11

With high power light emitting diodes and laser diodes being explored for white light generation and visible light communication, thermally robust encapsulation schemes for color-converting inorganic phosphors are essential. In the current work, the canonical blue-emitting phosphor, high purity Eu-doped BaMgAl 10O 17, has been prepared using microwave-assisted heating (25 min) and densified into translucent ceramic phosphor monoliths using spark plasma sintering (30 min). Lastly, the resulting translucent ceramic monoliths convert UV laser light to blue light with the same efficiency as the starting powder and provide superior thermal management in comparison with silicone encapsulation.

Facile self-assembly and stabilization of metal oxide nanoparticles.

PubMed

Charbonneau, Cecile; Holliman, Peter J; Davies, Matthew L; Watson, Trystan M; Worsley, David A

2015-03-15

This paper describes a facile method of self-assembling different metal oxide nanoparticles into nanostructured materials via di-carboxylate linkers (oxalic acid) using TiO2 as an example. In this method, the di-carboxylate linkers react with surface hydroxyls on metal oxide nanoparticles forming covalent, ester-like bonds, which enable the binding of two metal oxide particles, one at either end of the linker and facilitates efficient self-assembly of one group of metal oxide nanoparticles homogeneously distributed onto the surface of another group. The oxalate linkers can then be removed by thermal decomposition. This approach is shown to be effective using differently-sized TiO2 nanoparticles, namely in-house synthesized 3-5nm anatase nanocrystals and Degussa P25 titania particles (mean 21nm particle size). Our data show that the application of a high temperature heat treatment (450°C for 30min), conventionally applied to achieve a stable porous structure by thermal decomposition of the linker molecules and by inducing inter-particle necking, damages the surface area of the nanostructured material. However, here we show that sintering at 300°C for 30min or by flash near infrared radiation sintering for 12s efficiently decomposes the oxalate linkers and stabilizes the nanostructure of the material whilst maintaining its high surface area. Copyright © 2013 Elsevier Inc. All rights reserved.

Sun Emits a Mid-Level Flare on Dec. 4, 2014

NASA Image and Video Library

2017-12-08

The sun emitted a solar flare on Dec. 4, 2014, seen as the flash of light in this image from NASA's Solar Dynamics Observatory. The image blends two wavelengths of extreme ultraviolet light – 131 and 171 Angstroms – which are typically colored in teal and gold, respectively. Read more: 1.usa.gov/121n7PP Image Credit: NASA/SDO

Visualizing photosynthesis through processing of chlorophyll fluorescence images

NASA Astrophysics Data System (ADS)

Daley, Paul F.; Ball, J. Timothy; Berry, Joseph A.; Patzke, Juergen; Raschke, Klaus E.

1990-05-01

Measurements of terrestrial plant photosynthesis frequently exploit sensing of gas exchange from leaves enclosed in gas-tight, climate controlled chambers. These methods are typically slow, and do not resolve variation in photosynthesis below the whole leaf level. A photosynthesis visualization technique is presented that uses images of leaves employing light from chlorophyll (Chl) fluorescence. Images of Chl fluorescence from whole leaves undergoing steady-state photosynthesis, photosynthesis induction, or response to stress agents were digitized during light flashes that saturated photochemical reactions. Use of saturating flashes permitted deconvolution of photochemical energy use from biochemical quenching mechanisms (qN) that dissipate excess excitation energy, otherwise damaging to the light harvesting apparatus. Combination of the digital image frames of variable fluorescence with reference frames obtained from the same leaves when dark-adapted permitted derivation of frames in which grey scale represented the magnitude of qN. Simultaneous measurements with gas-exchange apparatus provided data for non-linear calibration filters for subsequent rendering of grey-scale "images" of photosynthesis. In several experiments significant non-homogeneity of photosynthetic activity was observed following treatment with growth hormones, or shifts in light or humidity, and following infection by virus. The technique provides a rapid, non-invasive probe for stress physiology and plant disease detection.

ODOT research news : spring 2010.

DOT National Transportation Integrated Search

2010-01-01

The newsletter includes: : 1) Some new research projects announced. : 2) After studying deer collision research and conferring with ODOT staff, Dr. Olsen thought that flashing lights may provide a low cost, short term, solution. That is, research sho...

Menopause

MedlinePlus

... and pelvis. Practice slow, deep breathing whenever a hot flash begins. Try taking 6 breaths a minute. Try yoga, tai chi, or meditation. Other tips: Dress lightly and in layers. Keep having sex. Use water-based lubricants or a vaginal moisturizer ...

Echoes of a Stellar Ending

NASA Image and Video Library

2012-03-14

Listed as Cassiopeia A, this remnant of the supernova is one of the brightest radio sources in the known universe. More recently, NASA WISE telescope detected infrared echoes of the flash of light rippling outwards from the supernova.

THEORY AND MEASUREMENT OF VISUAL MECHANISMS

PubMed Central

Crozier, W. J.; Wolf, Ernst

1941-01-01

For spectral regions associated with violet, blue, green, and red the relation between mean critical flash intensity Im for visual flicker and the flash frequency F is modified as already found with white light when the light time fraction tL in the flash cycle is changed. For a square image 6.13° on a side, foveally fixated, the "rod" and "cone" contributions to the duplex contour are analyzed in the way already used for white. It is pointed out that several customary qualitative criteria for cone functioning do not necessarily give concordant results. The analysis shows that the three parameters of the probability summations giving the "rod" and "cone" curves are changed independently as a function of wave-length composition of the light, and of the light time fraction. The correlation of these changes, and of those found in the associated variability functions, can be understood in terms of differences in (1) the numbers of neural units potentially excitable and (2) in the numbers of elements of neural effect obtained from them. In a multivariate situation of this kind it is necessary to compare intensities of luminous flux required to activate half the total population of potentially available elements when this total size is held constant for the different conditions. The results of this comparison, for the filtered lights used, are discussed in relation to certain aspects of excitation vs. wave-length. The problem is a general one, arising where the effects produced as a function of a particular variable are concerned. In the distinction between (1) units excited and (2) the actions they produce may be found the clue for the curious fact that with certain wave-lengths the critical intensities are lower than for white. The extension of the observations to other parts of the retina may be expected to further this analysis. PMID:19873261

Kinetics of oxygen consumption after a single flash of light in photoreceptors of the drone (Apis mellifera)

PubMed Central

1982-01-01

The time course of the rate of oxygen consumption (QO2) after a single flash of light has been measured in 300-micrometers slices of drone retina at 22 degrees C. To measure delta QO2(t), the change in QO2 from its level in darkness, the transients of the partial pressure of O2 (PO2) were recorded with O2 microelectrodes simultaneously in two sites in the slice and delta QO2 was calculated by a computer using Fourier transforms. After a 40-ms flash of intense light, delta QO2, reached a peak of 40 microliters O2/g.min and then declined exponentially to the baseline with a time constant tau 1 = 4.96 +/- 0.49 s (SD, n = 10). The rising phase was characterized by a time constant tau 2 = 1.90 +/- 0.35 s (SD, n = 10). The peak amplitude of delta QO2 increased linearly with the log of the light intensity. Replacement of Na+ by choline, known to decrease greatly the light-induced transmembrane current, caused a 63% decrease of delta QO2. With these changes, however, the kinetics of delta QO2 (t) were unchanged. This suggest that the recovery phase is rate-limited by a single reaction with apparent first-order kinetics. Evidence is provided that suggests that this reaction may be the working of the sodium pump. Exposure of the retina to high concentrations of ouabain or strophanthidin (inhibitors of the sodium pump) reduced the peak amplitude of delta QO2 by approximately 80% and increased tau 1. The increase of tau 1 was an exponential function of the time of exposure to the cardioactive steroids. Hence, it seems likely that the greatest part of delta QO2 is used for the working of the pump, whose activity is the mechanism underlying the rate constant of the descending limb of delta QO2 (t). PMID:6288837

Chromatic induction in space and time.

PubMed

Coia, Andrew J; Shevell, Steven K

2018-04-01

The color appearance of a light depends on variation in the complete visual field over both space and time. In the spatial domain, a chromatic stimulus within a patterned chromatic surround can appear a different hue than the same stimulus within a uniform surround. In the temporal domain, a stimulus presented as an element of a continuously changing chromaticity can appear a different color compared to the identical stimulus, presented simultaneously but viewed alone. This is the flash-lag effect for color, which has an analog in the domain of motion: a pulsed object seen alone can appear to lag behind an identical pulsed object that is an element of a motion sequence. Studies of the flash-lag effect for motion have considered whether it is mediated by a neural representation for the moving physical stimulus or, alternatively, for the perceived motion. The current study addresses this question for the flash-lag effect for color by testing whether the color flash lag depends on a representation of only the changing chromatic stimulus or, alternatively, its color percept, which can be altered by chromatic induction. baseline measurements for spatial chromatic induction determined the chromaticity of a flashed ring within a uniform surround that matched a flashed ring within a patterned surround. Baseline measurements for the color flash-lag effect determined the chromaticity of a pulsed ring presented alone (within a uniform surround) that matched a pulsed ring presented in a sequence of changing chromaticity over time (also within a uniform surround). Finally, the main experiments combined chromatic induction from a patterned surround and the flash-lag effect, in three conditions: (1) both the changing and pulsed rings were within a patterned chromatic surround; (2) the changing ring was within a patterned surround and the pulsed ring within a uniform surround; and (3) the changing ring was within a uniform surround and the pulsed ring within a patterned surround. the flash-lag measurements for a changing chromaticity were affected by perceptual changes induced by the surrounding chromatic pattern. Thus, the color shifts induced by a chromatic surround are incorporated in the neural representation mediating the flash-lag effect for color.

Anti-aging Friction of Carbonate Fault Mirror and its Microstructural Interpretation

NASA Astrophysics Data System (ADS)

Park, Y.; Ree, J. H.; Hirose, T.

2017-12-01

In our slide-hold-slide (SHS) friction tests on carbonate fault rocks, fault mirror (FM), light reflective mirror-like fault surface, shows almost zero or slightly negative aging rate of friction (`anti-aging' friction), whereas carbonate faults without FM exhibit a positive aging rate. We analyzed microstructures from three types of carbonate faults to explore the cause of the anti-aging friction of FM. The three types of fault rocks before SHS tests were made from Carrara marble; (i) FM, (ii) crushed gouge of former FM (CF), and (iii) gouge produced by pre-shearing of Carrara marble (PR). The fault zone of FM before SHS tests consists of sintered nanograin patches smeared into negative asperities of wall rocks (thickness up to 150 μm) and a sintered gouge layer between wall rocks (thickness up to 200 μm) that is composed of tightly-packed nanograins (50-500 nm in size) with triple junctions and angular-subangular fragments (a few-100 μm) of sintered nanograin aggregates. A straight and discrete Y-shear surface defines a boundary between the gouge layer and the nanograin patches or between the layer and wall rock. CF specimens before SHS tests are composed of patches of sintered nanograins as in FM specimens and a porous gouge layer with finer nanograins (a few-20 nm in size) and angular fragments of former FM. PR specimens before SHS tests are composed of damaged wall rocks and porous gouge with finer nanograins (a few-tens of μm). After SHS tests, sintered appearance of grains within the fault zones of CF and PR indicates the increase in interparticle bonding and also in contact area by grain aggregation. In contrast, the gouge layer of FM specimens after SHS tests consists mostly of angular fragments of sintered nanograin aggregates. The angular shape of the fragments indicates little increase in bonding and contact area between the fragments. Tightly sintered nanograins in FM specimens would have a lower chemical reactivity with their size coarser and sintering stronger than those of CF and PR. Furthermore, a high wear resistance of sintered nanograins of FM would prohibit generation of fine wear debris which may have led to the strenghtened interparticle bonding. Our results imply that anti-aging friction may be a common behavior other rocks' FM too, once they are composed of tightly sintered nanograins.

The Flash of Insight in Teaching and Tutoring....AHA, Eureka, It Dawned On Me, Light Bulb, Bolt of Lightning, Zeus, Epiphany

NASA Astrophysics Data System (ADS)

Gurr, Henry S.

1999-11-01

The fact that students have serious and rigidly held misconceptions in introductory physics classes is a common theme in recent physics teaching literature. Telling, or lecturing, often can not “get through” to the student. An effective remedial technique uses the so called “Flash of Insight”,(a mental “barrier penetration”) which may be most reliably achieved in the context of individual student tutoring. This talk will discuss how the teacher, having identified a point of confusion or misconception may precipitate the Flash of Insight, whereby the misguided student can be changed to correct thinking. The Flash of Insight is somewhat mysterious because it happens spontaneously, with little warning, and largely uncontrolled by the person involved except for the apparent struggle of preparation. However the Flash of Insight event has quite regular autonomic body signals which may be used as a valuable diagnostic “tool” to interpret the student’s state of conceptual progress. The physics teacher who becomes proficient in recognizing the series of student body signals, (starting from fixed rigid posture plus blank face, then suddenly shifting to smiling face and free body motions) will study the debilitating ways in which student learning can be reduced to a helpless standstill.

Improving Range Estimation of a 3-Dimensional Flash Ladar via Blind Deconvolution

DTIC Science & Technology

2010-09-01

12 2.1.4 Optical Imaging as a Linear and Nonlinear System 15 2.1.5 Coherence Theory and Laser Light Statistics . . . 16 2.2 Deconvolution...rather than deconvolution. 2.1.5 Coherence Theory and Laser Light Statistics. Using [24] and [25], this section serves as background on coherence theory...the laser light incident on the detector surface. The image intensity related to different types of coherence is governed by the laser light’s spatial

Sintering and crystallization behavior of CaMgSi{sub 2}O{sub 6}-NaFeSi{sub 2}O{sub 6} based glass-ceramics

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

Goel, Ashutosh; Kansal, Ishu; Dipartimento di Ingegneria dei Materiali e dell'Ambiente, Facolta di Ingegneria, Universita di Modena e Reggio Emilia, 41100 Modena

2009-11-01

We report on the synthesis, sintering, and crystallization behaviors of a glass with a composition corresponding to 90 mol % CaMgSi{sub 2}O{sub 6}-10 mol % NaFeSi{sub 2}O{sub 6}. The investigated glass composition crystallized superficially immediately after casting of the melt and needs a high cooling rate (rapid quenching) in order to produce an amorphous glass. Differential thermal analysis and hot-stage microscopy were employed to investigate the glass forming ability, sintering behavior, relative nucleation rate, and crystallization behavior of the glass composition. The crystalline phase assemblage in the glass-ceramics was studied under nonisothermal heating conditions in the temperature range of 850-950more » deg. C in both air and N{sub 2} atmosphere. X-ray diffraction studies adjoined with the Rietveld-reference intensity ratio method were employed to quantify the amount of crystalline phases, while electron microscopy was used to shed some light on the microstructure of the resultant glass-ceramics. Well sintered glass-ceramics with diopside as the primary crystalline phase were obtained where the amount of diopside varied with the heating conditions.« less

Understanding and improving optical coherence tomography imaging depth in selective laser sintering nylon 12 parts and powder

NASA Astrophysics Data System (ADS)

Lewis, Adam D.; Katta, Nitesh; McElroy, Austin; Milner, Thomas; Fish, Scott; Beaman, Joseph

2018-04-01

Optical coherence tomography (OCT) has shown promise as a process sensor in selective laser sintering (SLS) due to its ability to yield depth-resolved data not attainable with conventional sensors. However, OCT images of nylon 12 powder and nylon 12 components fabricated via SLS contain artifacts that have not been previously investigated in the literature. A better understanding of light interactions with SLS powder and components is foundational for further research expanding the utility of OCT imaging in SLS and other additive manufacturing (AM) sensing applications. Specifically, in this work, nylon powder and sintered parts were imaged in air and in an index matching liquid. Subsequent image analysis revealed the cause of "signal-tail" OCT image artifacts to be a combination of both inter and intraparticle multiple-scattering and reflections. Then, the OCT imaging depth of nylon 12 powder and the contrast-to-noise ratio of a sintered part were improved through the use of an index matching liquid. Finally, polymer crystals were identified as the main source of intraparticle scattering in nylon 12 powder. Implications of these results on future research utilizing OCT in SLS are also given.

77 FR 27539 - Petition for Waiver of Compliance

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-10

... position of the gate arm down and the flashing lights dark not be considered as an activation failure... docket number and may be submitted by any of the following methods: Web site: http://www.regulations.gov...

There's a Green Glob in Your Classroom.

ERIC Educational Resources Information Center

Dugdale, Sharon

1983-01-01

Discusses computer games (called intrinsic models) focusing on mathematics rather than on unrelated motivations (flashing lights or sounds). Games include "Green Globs," (equations/linear functions), "Darts"/"Torpedo" (fractions), "Escape" (graphing), and "Make-a-Monster" (equivalent fractions and…

AUTOMATIC COUNTER

DOEpatents

Robinson, H.P.

1960-06-01

An automatic counter of alpha particle tracks recorded by a sensitive emulsion of a photographic plate is described. The counter includes a source of mcdulated dark-field illumination for developing light flashes from the recorded particle tracks as the photographic plate is automatically scanned in narrow strips. Photoelectric means convert the light flashes to proportional current pulses for application to an electronic counting circuit. Photoelectric means are further provided for developing a phase reference signal from the photographic plate in such a manner that signals arising from particle tracks not parallel to the edge of the plate are out of phase with the reference signal. The counting circuit includes provision for rejecting the out-of-phase signals resulting from unoriented tracks as well as signals resulting from spurious marks on the plate such as scratches, dust or grain clumpings, etc. The output of the circuit is hence indicative only of the tracks that would be counted by a human operator.

Dissuasive exit signage for building fire evacuation.

PubMed

Olander, Joakim; Ronchi, Enrico; Lovreglio, Ruggiero; Nilsson, Daniel

2017-03-01

This work presents the result of a questionnaire study which investigates the design of dissuasive emergency signage, i.e. signage conveying a message of not utilizing a specific exit door. The work analyses and tests a set of key features of dissuasive emergency signage using the Theory of Affordances. The variables having the largest impact on observer preference, interpretation and noticeability of the signage have been identified. Results show that features which clearly negate the exit-message of the original positive exit signage are most effective, for instance a red X-marking placed across the entirety of the exit signage conveys a clear dissuasive message. Other features of note are red flashing lights and alternation of colour. The sense of urgency conveyed by the sign is largely affected by sensory inputs such as red flashing lights or other features which cause the signs to break the tendencies of normalcy. Copyright © 2016 Elsevier Ltd. All rights reserved.

Honeywell optical investigations on FLASH program

NASA Astrophysics Data System (ADS)

O'Rourke, Ken; Peterson, Eric; Yount, Larry

1995-05-01

The increasing performance and reduction of life cycle cost requirements placed on commercial and military transport aircraft are resulting in more complex, highly integrated aircraft control and management systems. The use of fiber optic data transmission media can make significant contributions in achieving these performance and cost goals. The Honeywell portion of Task 2A on the Fly-by-Light Advanced System Hardware (FLASH) program is evaluating a Primary Flight Control System (PFCS) using pilot and copilot inputs from Active Hand Controllers (AHC) which are optically linked to the primary flight Control Computers (PFCC). Customer involvement is an important element of the Task 2A activity. Establishing customer requirements and perspectives on productization of systems developed under FLASH are key to future product success. The Honeywell elements of the PFCS demonstrator provide a command path that is optically interfaced from crew inputs to commands of distributed, smart actuation subsystems commands. Optical communication architectures are implemented using several protocols including the new AS-1773A 20 Mbps data bus standard. The interconnecting fiber optic cable plant is provided by our Task 1A teammate McDonnell Douglas Aerospace (West). Fiber optic cable plant fabrication uses processed, tools and materials reflecting necessary advances in manufacturing required to make fly-by-light avionics systems marketable.

Modeling Studies of Inhomogeneity Effects during Laser Flash Photolysis Experiments: A Reaction-Diffusion Approach.

PubMed

Dóka, Éva; Lente, Gábor

2017-04-13

This work presents a rigorous mathematical study of the effect of unavoidable inhomogeneities in laser flash photolysis experiments. There are two different kinds of inhomegenities: the first arises from diffusion, whereas the second one has geometric origins (the shapes of the excitation and detection light beams). Both of these are taken into account in our reported model, which gives rise to a set of reaction-diffusion type partial differential equations. These equations are solved by a specially developed finite volume method. As an example, the aqueous reaction between the sulfate ion radical and iodide ion is used, for which sufficiently detailed experimental data are available from an earlier publication. The results showed that diffusion itself is in general too slow to influence the kinetic curves on the usual time scales of laser flash photolysis experiments. However, the use of the absorbances measured (e.g., to calculate the molar absorption coefficients of transient species) requires very detailed mathematical consideration and full knowledge of the geometrical shapes of the excitation laser beam and the separate detection light beam. It is also noted that the usual pseudo-first-order approach to evaluating the kinetic traces can be used successfully even if the usual large excess condition is not rigorously met in the reaction cell locally.

fMRI mapping of the visual system in the mouse brain with interleaved snapshot GE-EPI.

PubMed

Niranjan, Arun; Christie, Isabel N; Solomon, Samuel G; Wells, Jack A; Lythgoe, Mark F

2016-10-01

The use of functional magnetic resonance imaging (fMRI) in mice is increasingly prevalent, providing a means to non-invasively characterise functional abnormalities associated with genetic models of human diseases. The predominant stimulus used in task-based fMRI in the mouse is electrical stimulation of the paw. Task-based fMRI in mice using visual stimuli remains underexplored, despite visual stimuli being common in human fMRI studies. In this study, we map the mouse brain visual system with BOLD measurements at 9.4T using flashing light stimuli with medetomidine anaesthesia. BOLD responses were observed in the lateral geniculate nucleus, the superior colliculus and the primary visual area of the cortex, and were modulated by the flashing frequency, diffuse vs focussed light and stimulus context. Negative BOLD responses were measured in the visual cortex at 10Hz flashing frequency; but turned positive below 5Hz. In addition, the use of interleaved snapshot GE-EPI improved fMRI image quality without diminishing the temporal contrast-noise-ratio. Taken together, this work demonstrates a novel methodological protocol in which the mouse brain visual system can be non-invasively investigated using BOLD fMRI. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Stress insensitive multilayer chip inductor with ferrite core

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

Vishwas, B.; Madhuri, W., E-mail: madhuriw12@gmail.com; Rao, N. Madhusudan

2015-06-24

Mg{sub 0.25}Cu{sub 0.25}Zn{sub 0.5}Fe{sub 2}O{sub 4} is synthesized by sol gel auto combustion technique. The obtained ferrite powder is finally sintered in a microwave furnace at 850°C. Multilayer chip inductor (MLCI) of two layers is prepared by screen printing technique. The sintered ferrite is characterized by X-ray diffraction. The frequency response of dielectric constant is studied in the frequency range of 100Hz to 5MHz. Dielectric polarization is discussed in the light of Maxwell-Wagner interfacial polarization. The prepared MLCI is studied for stress sensitivity in the range of 0 to 8 MPa.

Visible light emission measurements from a dense electrothermal launcher plasma

NASA Astrophysics Data System (ADS)

Hankins, O. E.; Bourham, M. A.; Earnhart, J.; Gilligan, J. G.

1993-01-01

Measurements of the visible light emission from dense, weakly non-ideal plasmas have been performed on the experimental electrothermal launcher device 'SIRENS'. The plasma is created by the ablation or a Lexan insulator in the source, which then flows through a cylindrical barrel which serves as the material sample. Visible light emission spectra have been observed both in-bore and from the muzzle flash or the barrel, and from the flash or the source. Due to high plasma opacity (the plasma emits as a near blackbody) and absorption by the molecular components of the vapor shield, the hotter core or the arc has been difficult to observe. Recent measurements along the axis or the device indicate time-averaged plasma temperatures in the barrel or about 1 eV for lower energy shots, which agree with experimental measurements of the average heat flux and plasma conductivity along the barrel. Measurements or visible emission from the source indicate time averaged temperatures of 1 to 2 eV which agree with the theoretical estimates derived from ablated mass measurements and calculated estimates derived from plasma conductivity measurements.

Study of firefly luciferin oxidation and isomerism as possible inhibition pathways for firefly bioluminescence

NASA Astrophysics Data System (ADS)

Pinto da Silva, Luís; Esteves da Silva, Joaquim C. G.

2014-01-01

Firefly bioluminescence presents a light emitting profile with a form of a flash, due to the firefly luciferase-catalyzed formation of inhibitory products. These impair the binding of the substrate luciferin to the active site of the enzyme. However, this luciferase catalyzed pathways may not be the only ones responsible for the flash profile. The oxidation and isomerisation of the substrate luciferin lead to the formation of compounds that are also known inhibitors of firefly bioluminescence. So, the objective of this Letter was to analyze if these reactions could be capable of interfering with the bioluminescence reaction.

Lunar Impact Flash Locations from NASA's Lunar Impact Monitoring Program

NASA Technical Reports Server (NTRS)

Moser, D. E.; Suggs, R. M.; Kupferschmidt, L.; Feldman, J.

2015-01-01

Meteoroids are small, natural bodies traveling through space, fragments from comets, asteroids, and impact debris from planets. Unlike the Earth, which has an atmosphere that slows, ablates, and disintegrates most meteoroids before they reach the ground, the Moon has little-to-no atmosphere to prevent meteoroids from impacting the lunar surface. Upon impact, the meteoroid's kinetic energy is partitioned into crater excavation, seismic wave production, and the generation of a debris plume. A flash of light associated with the plume is detectable by instruments on Earth. Following the initial observation of a probable Taurid impact flash on the Moon in November 2005,1 the NASA Meteoroid Environment Office (MEO) began a routine monitoring program to observe the Moon for meteoroid impact flashes in early 2006, resulting in the observation of over 330 impacts to date. The main objective of the MEO is to characterize the meteoroid environment for application to spacecraft engineering and operations. The Lunar Impact Monitoring Program provides information about the meteoroid flux in near-Earth space in a size range-tens of grams to a few kilograms-difficult to measure with statistical significance by other means. A bright impact flash detected by the program in March 2013 brought into focus the importance of determining the impact flash location. Prior to this time, the location was estimated to the nearest half-degree by visually comparing the impact imagery to maps of the Moon. Better accuracy was not needed because meteoroid flux calculations did not require high-accuracy impact locations. But such a bright event was thought to have produced a fresh crater detectable from lunar orbit by the NASA spacecraft Lunar Reconnaissance Orbiter (LRO). The idea of linking the observation of an impact flash with its crater was an appealing one, as it would validate NASA photometric calculations and crater scaling laws developed from hypervelocity gun testing. This idea was dependent upon LRO finding a fresh impact crater associated with one of the impact flashes recorded by Earth-based instruments, either the bright event of March 2013 or any other in the database of impact observations. To find the crater, LRO needed an accurate area to search. This Technical Memorandum (TM) describes the geolocation technique developed to accurately determine the impact flash location, and by association, the location of the crater, thought to lie directly beneath the brightest portion of the flash. The workflow and software tools used to geolocate the impact flashes are described in detail, along with sources of error and uncertainty and a case study applying the workflow to the bright impact flash in March 2013. Following the successful geolocation of the March 2013 flash, the technique was applied to all impact flashes detected by the MEO between November 7, 2005, and January 3, 2014.

Grain growth in uranium nitride prepared by spark plasma sintering

NASA Astrophysics Data System (ADS)

Johnson, Kyle D.; Lopes, Denise Adorno

2018-05-01

Uranium mononitride (UN) has long been considered a potential high density, high performance fuel candidate for light water reactor (LWR) and fast reactor (FR) applications. However, deployability of this fuel has been limited by the notable resistance to sintering and subsequent difficulty in producing a desirable microstructure, the high costs associated with 15N enrichment, as well as the known proclivity to oxidation and interaction with steam. In this study, the stimulation of grain growth in UN pellets sintered using SPS has been investigated. The results reveal that by using SPS and controlling temperature, time, and holding pressure, grain growth can be stimulated and controlled to produce a material featuring both a desired porosity and grain size, at least within the range of interest for nuclear fuel candidates. Grain sizes up to 31 μm were obtained using temperatures of 1650 °C and hold times of 15 min. Evaluation by EBSD reveal grain rotation and coalescence as the dominant mechanism in grain growth, which is suppressed by the application of higher external pressure. Moreover, complete closure of the porosity of the material was observed at relative densities of 96% TD, resulting in a material with sufficient porosity to accommodate LWR burnup. These results indicate that a method exists for the economic fabrication of an 15N-bearing uranium mononitride fuel with favorable microstructural characteristics compatible with use in a light water-cooled nuclear reactor.

Solar simulator for concentrator photovoltaic systems.

PubMed

Domínguez, César; Antón, Ignacio; Sala, Gabriel

2008-09-15

A solar simulator for measuring performance of large area concentrator photovoltaic (CPV) modules is presented. Its illumination system is based on a Xenon flash light and a large area collimator mirror, which simulates natural sun light. Quality requirements imposed by the CPV systems have been characterized: irradiance level and uniformity at the receiver, light collimation and spectral distribution. The simulator allows indoor fast and cost-effective performance characterization and classification of CPV systems at the production line as well as module rating carried out by laboratories.

Ionization and Corona Discharges from Stressed Rocks

NASA Astrophysics Data System (ADS)

Winnick, M. J.; Kulahci, I.; Cyr, G.; Tregloan-Reed, J.; Freund, F. T.

2008-12-01

Pre-earthquake signals have long been observed and documented, though they have not been adequately explained scientifically. These signals include air ionization, occasional flashes of light from the ground, radio frequency emissions, and effects on the ionosphere that occur hours or even days before large earthquakes. The theory that rocks function as p-type semiconductors when deviatoric stresses are applied offers a mechanism for this group of earthquake precursors. When an igneous or high-grade metamorphic rock is subjected to deviatoric stresses, peroxy bonds that exist in the rock's minerals as point defects dissociate, releasing positive hole charge carriers. The positive holes travel by phonon-assisted electron hopping from the stressed into and through the unstressed rock volume and build up a positive surface charge. At sufficiently large electric fields, especially along edges and sharp points of the rock, air molecules become field-ionized, loosing an electron to the rock surface and turning into airborne positive ions. This in turn can lead to corona discharges, which manifest themselves by flashes of light and radio frequency emissions. We applied concentrated stresses to one end of a block of gabbro, 30 x 15 x 10 cm3, inside a shielded Faraday cage and observed positive ion currents through an air gap about 25 cm from the place where the stresses were applied, punctuated by short bursts, accompanied by flashes of light and radio frequency emissions characteristic of a corona discharge. These observations may serve to explain a range of pre-earthquake signals, in particular changes in air conductivity, luminous phenomena, radio frequency noise, and ionospheric perturbations.

Pressure and temperature dependence kinetics study of the NO + BrO yielding NO2 + Br reaction - Implications for stratospheric bromine photochemistry

NASA Technical Reports Server (NTRS)

Watson, R. T.; Sander, S. P.; Yung, Y. L.

1979-01-01

The reactivity of NO with BrO radicals over a wide range of pressure (100-700 torr) and temperature (224-398 K) is investigated using the flash photolysis-ultraviolet absorption technique. The flash photolysis system consists of a high-pressure xenon arc light source, a reaction cell/gas filter/flash lamp combination, and a 216.5 half-meter monochromator/polychromator/spectrography for wavelength selectivity. The details of the reaction and its corresponding Arrhenius expression are identified. The results are compared with previous measurements, and atmospheric implications of the reaction are discussed. The NO + BrO yielding NO2 + Br reaction is shown to be important in controlling the concentration ratios of BrO/Br and BrO/HBr in the stratosphere, but this reaction does not affect the catalytic efficiency of BrOx in ozone destruction.

Flash characteristics of plasma induced by hypervelocity impact

NASA Astrophysics Data System (ADS)

Zhang, Kai; Long, Renrong; Zhang, Qingming; Xue, Yijiang; Ju, Yuanyuan

2016-08-01

Using a two-stage light gas gun, a series of hypervelocity impact experiments was conducted in which 6.4-mm-diameter spherical 2024-aluminum projectiles impact 23-mm-thick targets made of the same material at velocities of 5.0, 5.6, and 6.3 km/s. Both an optical pyrometer composed of six photomultiplier tubes and a spectrograph were used to measure the flash of the plasma during hypervelocity impact. Experimental results show that, at a projectile velocity of 6.3 km/s, the strong flash lasted about 10 μs and reached a temperature of 4300 K. Based on the known emission lines of AL I, spectral methods can provide the plasma electron temperature. An electron-temperature comparison between experiment and theoretical calculation indicates that single ionization and secondary ionization are the two main ionizing modes at velocities 5.0-6.3 km/s.

Flash characteristics of plasma induced by hypervelocity impact

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

Zhang, Kai; Beijing Automotive Technology Center, Beijing 100021; Long, Renrong, E-mail: longrenrong@bit.edu.cn, E-mail: qmzhang@bit.edu.cn

2016-08-15

Using a two-stage light gas gun, a series of hypervelocity impact experiments was conducted in which 6.4-mm-diameter spherical 2024-aluminum projectiles impact 23-mm-thick targets made of the same material at velocities of 5.0, 5.6, and 6.3 km/s. Both an optical pyrometer composed of six photomultiplier tubes and a spectrograph were used to measure the flash of the plasma during hypervelocity impact. Experimental results show that, at a projectile velocity of 6.3 km/s, the strong flash lasted about 10 μs and reached a temperature of 4300 K. Based on the known emission lines of AL I, spectral methods can provide the plasma electron temperature. An electron-temperaturemore » comparison between experiment and theoretical calculation indicates that single ionization and secondary ionization are the two main ionizing modes at velocities 5.0–6.3 km/s.« less

78 FR 38200 - Safety Zones; Annual Independence Day Fireworks Displays, Skagway, Haines, and Wrangell, AK

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-26

..., darkness punctuated by bright flashes of light, and burning debris has the potential to result in serious... enforcement of these safety zones will be of short duration, approximately three hours. Furthermore, vessels...

Interior, building 1205, view to west showing roof truss system, ...

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

Interior, building 1205, view to west showing roof truss system, 90 mm lens plus electronic flash fill lighting. - Travis Air Force Base, Readiness Maintenance Hangar, W Street, Air Defense Command Readiness Area, Fairfield, Solano County, CA

Alternative food safety intervention technologies: flash pasteurization of finfish

USDA-ARS?s Scientific Manuscript database

Alternative nonthermal and thermal food safety interventions are gaining acceptance by the food processing industry and consumers. These technologies include high pressure processing, ultraviolet and pulsed light, ionizing radiation, pulsed and radiofrequency electric fields, cold atmospheric plasm...

Utilizing ISS Camera Systems for Scientific Analysis of Lightning Characteristics and comparison with ISS-LIS and GLM

NASA Astrophysics Data System (ADS)

Schultz, C. J.; Lang, T. J.; Leake, S.; Runco, M.; Blakeslee, R. J.

2017-12-01

Video and still frame images from cameras aboard the International Space Station (ISS) are used to inspire, educate, and provide a unique vantage point from low-Earth orbit that is second to none; however, these cameras have overlooked capabilities for contributing to scientific analysis of the Earth and near-space environment. The goal of this project is to study how georeferenced video/images from available ISS camera systems can be useful for scientific analysis, using lightning properties as a demonstration. Camera images from the crew cameras and high definition video from the Chiba University Meteor Camera were combined with lightning data from the National Lightning Detection Network (NLDN), ISS-Lightning Imaging Sensor (ISS-LIS), the Geostationary Lightning Mapper (GLM) and lightning mapping arrays. These cameras provide significant spatial resolution advantages ( 10 times or better) over ISS-LIS and GLM, but with lower temporal resolution. Therefore, they can serve as a complementarity analysis tool for studying lightning and thunderstorm processes from space. Lightning sensor data, Visible Infrared Imaging Radiometer Suite (VIIRS) derived city light maps, and other geographic databases were combined with the ISS attitude and position data to reverse geolocate each image or frame. An open-source Python toolkit has been developed to assist with this effort. Next, the locations and sizes of all flashes in each frame or image were computed and compared with flash characteristics from all available lightning datasets. This allowed for characterization of cloud features that are below the 4-km and 8-km resolution of ISS-LIS and GLM which may reduce the light that reaches the ISS-LIS or GLM sensor. In the case of video, consecutive frames were overlaid to determine the rate of change of the light escaping cloud top. Characterization of the rate of change in geometry, more generally the radius, of light escaping cloud top was integrated with the NLDN, ISS-LIS and GLM to understand how the peak rate of change and the peak area of each flash aligned with each lightning system in time. Flash features like leaders could be inferred from the video frames as well. Testing is being done to see if leader speeds may be accurately calculated under certain circumstances.

The quality study of recycled glass phosphor waste for LED

NASA Astrophysics Data System (ADS)

Tsai, Chun-Chin; Chen, Guan-Hao; Yue, Cheng-Feng; Chen, Cin-Fu; Cheng, Wood-Hi

2017-02-01

To study the feasibility and quality of recycled glass phosphor waste for LED packaging, the experiments were conducted to compare optical characteristics between fresh color conversion layer and that made of recycled waste. The fresh color conversion layer was fabricated through sintering pristine mixture of Y.A.G. powder [yellow phosphor (Y3AlO12 : Ce3+). Those recycled waste glass phosphor re-melted to form Secondary Molten Glass Phosphor (S.M.G.P.). The experiments on such low melting temperature glass results showed that transmission rates of S.M.G.P. are 9% higher than those of first-sintered glass phosphor, corresponding to 1.25% greater average bubble size and 36% more bubble coverage area in S.M.G.P. In the recent years, high power LED modules and laser projectors have been requiring higher thermal stability by using glass phosphor materials for light mixing. Nevertheless, phosphor and related materials are too expensive to expand their markets. It seems a right trend and research goal that recycling such waste of high thermal stability and quality materials could be preferably one of feasible cost-down solutions. This technical approach could bring out brighter future for solid lighting and light source module industries.

Characterization of the distribution of the sintering activator boron in powder metallurgical steels with SIMS.

PubMed

Krecar, Dragan; Vassileva, Vassilka; Danninger, Herbert; Hutter, Herbert

2004-06-01

Powder metallurgy is a well-established method for manufacturing ferrous precision parts. A very important step is sintering, which can be strongly enhanced by the formation of a liquid phase during the sintering process. Boron activates this process by forming such a liquid phase at about 1200 degrees C. In this work, the sintering of Fe-B was performed under the protective atmospheres of hydrogen, argon or nitrogen. Using different grain sizes of the added ferroboron leads to different formations of pores and to the formation of secondary pores. The effect of boron was investigated by means of Secondary Ion Mass Spectrometry (SIMS) supported by Scanning Electron Microscopy (SEM) and Light Microscopy (LM). To verify the influence of the process parameters on the mechanical properties, the microstructure (pore shape) was examined and impact energy measurements were performed. The concentrations of B in different samples were varied from 0.03-0.6 weight percent (wt%). Higher boron concentrations are detectable by EPMA, whereas the distributions of boron in the samples with interesting overall concentration in the low wt% range are only detectable by means of SIMS. This work shows that the distribution of boron strongly depends on its concentration and the sintering atmosphere used. At low concentration (up to 0.1 wt%) there are boride precipitations; at higher concentration there is a eutectic iron-boron grain boundary network. There is a decrease of the impact energy observed that correlates with the amount of eutectic phase.

SinterHab

NASA Astrophysics Data System (ADS)

Rousek, Tomáš; Eriksson, Katarina; Doule, Ondřej

2012-05-01

This project describes a design study for a core module on a Lunar South Pole outpost, constructed by 3D printing technology with the use of in-situ resources and equipped with a bio-regenerative life support system. The module would be a hybrid of deployable (CLASS II) and in-situ built (CLASS III) structures. It would combine deployable membrane structures and pre-integrated rigid elements with a sintered regolith shell for enhanced radiation and micrometeorite shielding. The closed loop ecological system would support a sustainable presence on the Moon with particular focus on research activities. The core module accommodates from four to eight people, and provides laboratories as a test bed for development of new lunar technologies directly in the environment where they will be used. SinterHab also includes an experimental garden for development of new bio-regenerative life support system elements. The project explores these various concepts from an architectural point-of-view particularly, as they constitute the building, construction and interior elements. The construction method for SinterHab is based on 3D printing by sintering of the lunar regolith. Sinterator robotics 3D printing technology proposed by NASA JPL enables construction of future generations of large lunar settlements with little imported material and the use of solar energy. The regolith is processed, placed and sintered by the Sinterator robotics system which combines the NASA ATHLETE and the Chariot remotely controlled rovers. Microwave sintering creates a rigid structure in the form of walls, vaults and other architectural elements. The interior is coated with a layer of inflatable membranes inspired by the TransHab project. The life-support system is mainly bio-regenerative and several parts of the system are intrinsically multifunctional and serve more than one purpose. The plants for food production are also an efficient part of atmosphere revitalization and water treatment. Moreover, the plants will be used as a "winter garden" for psychological and recreational purposes. The water in the revitalization system has a multifunctional use, as radiation shielding in the safe-haven habitat core. The garden module creates an artificial outdoor environment mitigating the notion of confinement on the lunar surface. Fiber optics systems and plasma lamps are used for transmission of natural and artificial light into the interior.

Rapid, cool sintering of wet processed yttria-stabilized zirconia ceramic electrolyte thin films.

PubMed

Park, Jun-Sik; Kim, Dug-Joong; Chung, Wan-Ho; Lim, Yonghyun; Kim, Hak-Sung; Kim, Young-Beom

2017-09-29

Here we report a photonic annealing process for yttria-stabilized zirconia films, which are one of the most well-known solid-state electrolytes for solid oxide fuel cells (SOFCs). Precursor films were coated using a wet-chemical method with a simple metal-organic precursor solution and directly annealed at standard pressure and temperature by two cycles of xenon flash lamp irradiation. The residual organics were almost completely decomposed in the first pre-annealing step, and the fluorite crystalline phases and good ionic conductivity were developed during the second annealing step. These films showed properties comparable to those of thermally annealed films. This process is much faster than conventional annealing processes (e.g. halogen furnaces); a few seconds compared to tens of hours, respectively. The significance of this work includes the treatment of solid-state electrolyte oxides for SOFCs and the demonstration of the feasibility of other oxide components for solid-state energy devices.

Dip-coating of nano-sized CeO2 on SiC membrane and its effect on thermal diffusivity.

PubMed

Park, Jihye; Jung, Miewon

2014-05-01

CeO2-SiC mixed composite membrane was fabricated with porous SiC ceramic and cerium oxide powder synthesized by sol-gel process. This CeO2-SiC membrane and SiC membrane which is made by the purified SiC ceramic were pressed and sintered in Ar atmosphere. And then, the SiC membrane was dip-coated by cerium oxide precursor sol solution and heat-treated in air. The surface morphology, particle size, porosity and structure analysis of the mixing and dip-coating SiC membrane were monitored by FE-SEM and X-ray diffraction analysis. Surface area, pore volume and pore diameter were determined by BET instrument. Thermal diffusivity was measured by laser flash method with increasing temperature. The relation between porosity and thermal diffusivity from different preparation process has been discussed on this study.

Next Generation Thermal Barrier Coatings for the Gas Turbine Industry

NASA Astrophysics Data System (ADS)

Curry, Nicholas; Markocsan, Nicolaie; Li, Xin-Hai; Tricoire, Aurélien; Dorfman, Mitch

2011-01-01

The aim of this study is to develop the next generation of production ready air plasma sprayed thermal barrier coating with a low conductivity and long lifetime. A number of coating architectures were produced using commercially available plasma spray guns. Modifications were made to powder chemistry, including high purity powders, dysprosia stabilized zirconia powders, and powders containing porosity formers. Agglomerated & sintered and homogenized oven spheroidized powder morphologies were used to attain beneficial microstructures. Dual layer coatings were produced using the two powders. Laser flash technique was used to evaluate the thermal conductivity of the coating systems from room temperature to 1200 °C. Tests were performed on as-sprayed samples and samples were heat treated for 100 h at 1150 °C. Thermal conductivity results were correlated to the coating microstructure using image analysis of porosity and cracks. The results show the influence of beneficial porosity on reducing the thermal conductivity of the produced coatings.

Utility of a simple lighting device to improve chest compressions learning.

PubMed

González-Calvete, L; Barcala-Furelos, R; Moure-González, J D; Abelairas-Gómez, C; Rodríguez-Núñez, A

2017-11-01

The recommendations on cardiopulmonary resuscitation (CPR) emphasize the quality of the manoeuvres, especially chest compressions (CC). Audiovisual feedback devices could improve the quality of the CC during CPR. The aim of this study was to evaluate the usefulness of a simple lighting device as a visual aid during CPR on a mannequin. Twenty-two paediatricians who attended an accredited paediatric CPR course performed, in random order, 2min of CPR on a mannequin without and with the help of a simple lighting device, which flashes at a frequency of 100 cycles per minute. The following CC variables were analyzed using a validated compression quality meter (CPRmeter ® ): depth, decompression, rate, CPR time and percentage of compressions. With the lighting device, participants increased average quality (60.23±54.50 vs. 79.24±9.80%; P=.005), percentage in target depth (48.86±42.67 vs. 72.95±20.25%; P=.036) and rate (35.82±37.54 vs. 67.09±31.95%; P=.024). A simple light device that flashes at the recommended frequency improves the quality of CC performed by paediatric residents on a mannequin. The usefulness of this CPR aid system should be assessed in real patients. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Fully Solution-Processable Fabrication of Multi-Layered Circuits on a Flexible Substrate Using Laser Processing

PubMed Central

Ji, Seok Young; Choi, Wonsuk; Jeon, Jin-Woo; Chang, Won Seok

2018-01-01

The development of printing technologies has enabled the realization of electric circuit fabrication on a flexible substrate. However, the current technique remains restricted to single-layer patterning. In this paper, we demonstrate a fully solution-processable patterning approach for multi-layer circuits using a combined method of laser sintering and ablation. Selective laser sintering of silver (Ag) nanoparticle-based ink is applied to make conductive patterns on a heat-sensitive substrate and insulating layer. The laser beam path and irradiation fluence are controlled to create circuit patterns for flexible electronics. Microvia drilling using femtosecond laser through the polyvinylphenol-film insulating layer by laser ablation, as well as sequential coating of Ag ink and laser sintering, achieves an interlayer interconnection between multi-layer circuits. The dimension of microvia is determined by a sophisticated adjustment of the laser focal position and intensity. Based on these methods, a flexible electronic circuit with chip-size-package light-emitting diodes was successfully fabricated and demonstrated to have functional operations. PMID:29425144

33 CFR 165.819 - Security Zone; Sabine Bank Channel, Sabine Pass Channel and Sabine-Neches Waterway, TX.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Broadcast Notice to Mariners and the presence of escort vessels displaying flashing blue law enforcement lights. (b) Regulations. (1) Entry into or remaining in a fixed security zone described in paragraph (a...

33 CFR 165.819 - Security Zone; Sabine Bank Channel, Sabine Pass Channel and Sabine-Neches Waterway, TX.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Broadcast Notice to Mariners and the presence of escort vessels displaying flashing blue law enforcement lights. (b) Regulations. (1) Entry into or remaining in a fixed security zone described in paragraph (a...

33 CFR 165.819 - Security Zone; Sabine Bank Channel, Sabine Pass Channel and Sabine-Neches Waterway, TX.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Broadcast Notice to Mariners and the presence of escort vessels displaying flashing blue law enforcement lights. (b) Regulations. (1) Entry into or remaining in a fixed security zone described in paragraph (a...

33 CFR 165.819 - Security Zone; Sabine Bank Channel, Sabine Pass Channel and Sabine-Neches Waterway, TX.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Broadcast Notice to Mariners and the presence of escort vessels displaying flashing blue law enforcement lights. (b) Regulations. (1) Entry into or remaining in a fixed security zone described in paragraph (a...

46 CFR 161.013-5 - Intensity requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... of the light corrected for the length of the flash and is determined by the formula: EFI = I × (tc − ti) / 0.2 + (tc − ti) Where: I is the measured intensity of the fixed beam, tc is the contact closure...

Success in Redesigning Main Streets for Pedestrians

DOT National Transportation Integrated Search

1998-09-16

In the fall of 1997, the city of Kirkland installed small flashing LEDs in the : pavement at two crosswalks. Devices are installed across all travel lanes for : both directions of travel on each side of the crosswalk. When activated, : lights in the ...

Interior detail, view to northnortheast showing support system for roof ...

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

Interior detail, view to north-northeast showing support system for roof truss (typical), 90 mm lens plus electronic flash lighting. - Travis Air Force Base, Readiness Maintenance Hangar, W Street, Air Defense Command Readiness Area, Fairfield, Solano County, CA

46 CFR 161.013-5 - Intensity requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... of the light corrected for the length of the flash and is determined by the formula: EFI = I × (tc − ti) / 0.2 + (tc − ti) Where: I is the measured intensity of the fixed beam, tc is the contact closure...

33 CFR 126.16 - Conditions for designating a “facility of particular hazard.”

Code of Federal Regulations, 2010 CFR

2010-07-01

... shall be of the siren type, or the emergency rotating flashing light type, and be of sufficient... signal shall not conflict with local municipal prescription. [CGFR 67-93, 32 FR 20774, Dec. 23, 1967] ...

Variation in Rhodopsin Kinase Expression Alters the Dim Flash Response Shut Off and the Light Adaptation in Rod Photoreceptors

PubMed Central

Sakurai, Keisuke; Young, Joyce E.; Kefalov, Vladimir J.; Khani, Shahrokh C.

2011-01-01

Purpose. Rod photoreceptors are exquisitely sensitive light detectors that function in dim light. The timely inactivation of their light responses is critical for the ability of rods to reliably detect and count photons. A key step in the inactivation of the rod transduction is the phosphorylation of the rod visual pigment, rhodopsin, catalyzed by G-protein-dependent receptor kinase 1 (GRK1). Absence of GRK1 greatly prolongs the photoreceptors' light response and enhances their susceptibility to degeneration. This study examined the light responses from mouse rods expressing various levels of GRK1 to evaluate how their function is modulated by rhodopsin inactivation. Methods. Transretinal and single-cell rod electrophysiological recordings were obtained from several strains of mice expressing GRK1 at 0.3- to 3-fold the wild-type levels. The effect of GRK1 expression level on the function of mouse rods was examined in darkness and during background adaptation. Results. Altering the expression of GRK1 from 0.3- to 3-fold that in wild-type rods had little effect on the single photon response amplitude. Notably, increasing the expression level of GRK1 accelerated the dim flash response shut off but had no effect on the saturated response shut off. Additionally, GRK1 excess abolished the acceleration of saturated responses shut off during light adaptation. Conclusions. These results demonstrate that rhodopsin inactivation can modulate the kinetics of recovery from dim light stimulation. More importantly, the ratio of rhodopsin kinase to its modulator recoverin appears critical for the proper adaptation of rods and the acceleration of their response shut off in background light. PMID:21474765

Variation in rhodopsin kinase expression alters the dim flash response shut off and the light adaptation in rod photoreceptors.

PubMed

Sakurai, Keisuke; Young, Joyce E; Kefalov, Vladimir J; Khani, Shahrokh C

2011-08-29

Rod photoreceptors are exquisitely sensitive light detectors that function in dim light. The timely inactivation of their light responses is critical for the ability of rods to reliably detect and count photons. A key step in the inactivation of the rod transduction is the phosphorylation of the rod visual pigment, rhodopsin, catalyzed by G-protein-dependent receptor kinase 1 (GRK1). Absence of GRK1 greatly prolongs the photoreceptors' light response and enhances their susceptibility to degeneration. This study examined the light responses from mouse rods expressing various levels of GRK1 to evaluate how their function is modulated by rhodopsin inactivation. Transretinal and single-cell rod electrophysiological recordings were obtained from several strains of mice expressing GRK1 at 0.3- to 3-fold the wild-type levels. The effect of GRK1 expression level on the function of mouse rods was examined in darkness and during background adaptation. Altering the expression of GRK1 from 0.3- to 3-fold that in wild-type rods had little effect on the single photon response amplitude. Notably, increasing the expression level of GRK1 accelerated the dim flash response shut off but had no effect on the saturated response shut off. Additionally, GRK1 excess abolished the acceleration of saturated responses shut off during light adaptation. These results demonstrate that rhodopsin inactivation can modulate the kinetics of recovery from dim light stimulation. More importantly, the ratio of rhodopsin kinase to its modulator recoverin appears critical for the proper adaptation of rods and the acceleration of their response shut off in background light.

Pigeons' Memory for Number of Events: Effects of Intertrial Interval and Delay Interval Illumination

ERIC Educational Resources Information Center

Hope, Chris; Santi, Angelo

2004-01-01

In Experiment 1, pigeons were trained at a 0-s baseline delay to discriminate sequences of light flashes (illumination of the feeder) that varied in number but not time (2f/4s and 8f/4s). During training, the intertrial interval was illuminated by the houselight for Group Light, but it was dark for Group Dark. Testing conducted with dark delay…

Correlated peak relative light intensity and peak current in triggered lightning subsequent return strokes

NASA Technical Reports Server (NTRS)

Idone, V. P.; Orville, R. E.

1985-01-01

The correlation between peak relative light intensity L(R) and stroke peak current I(R) is examined for 39 subsequent return strokes in two triggered lightning flashes. One flash contained 19 strokes and the other 20 strokes for which direct measurements were available of the return stroke peak current at ground. Peak currents ranged from 1.6 to 21 kA. The measurements of peak relative light intensity were obtained from photographic streak recordings using calibrated film and microsecond resolution. Correlations, significant at better than the 0.1 percent level, were found for several functional relationships. Although a relation between L(R) and I(R) is evident in these data, none of the analytical relations considered is clearly favored. The correlation between L(R) and the maximum rate of current rise is also examined, but less correlation than between L(R) and I(R) is found. In addition, the peak relative intensity near ground is evaluated for 22 dart leaders, and a mean ratio of peak dart leader to peak return stroke relative light intensity was found to be 0.1 with a range of 0.02-0.23. Using two different methods, the peak current near ground in these dart leaders is estimated to range from 0.1 to 6 kA.

The reciprocal relation between lightning and pollution and their impact over Kolkata, India.

PubMed

Middey, Anirban; Chaudhuri, Sutapa

2013-05-01

Aerosol loading in the atmosphere can cause increased lightning flashes, and those lightning flashes produce NOX , which reacts in sun light to produce surface ozone. The present study deals with the effect of surface pollutants on premonsoon (April-May) lightning activity over the station Kolkata (22.65° N, 88.45° E). Seven-year (2004-2010) premonsoon thunderstorms data are taken for the study. Different parameters like aerosol optical depth and cloud top temperature from the Moderate Resolution Imaging Spectroradiometer satellite products along with lightning flash data from Tropical Rainfall Measuring Mission's (TRMM) Lightning Imaging Sensor are analyzed. Some surface pollution parameters like suspended particulate matter, particulate matter 10, nitrogen oxides (NOX), and surface ozone (O₃) data during the same period are taken account for clear understanding of their association with lightning activity. Heights of convective condensation level and lifting condensation level are collected from radiosonde observations to anticipate about cloud base. It is found that increased surface pollution in a near storm environment is related to increased lightning flash rate, which results in increased surface NOX and consequently increased surface ozone concentration over the station Kolkata.

Sintering of highly porous silica-particle samples: analogues of early Solar-System aggregates

NASA Astrophysics Data System (ADS)

Poppe, T.

2003-07-01

I describe a new method to make particle layers which consist of SiO 2 spheres with 0.78 μm radius. The layers were produced by sedimentation of aggregates which had grown in ballistic particle collisions, and the layers had a porosity of 0.95. They were used for experiments on sintering, i.e., the samples were heated in an oven at varying temperatures and heating durations, and the samples were analyzed by scanning electron microscopy. Based on the change of particle diameter, surface diffusion sintering and viscous flow are identified as important transformation mechanisms. The first effect dominated at the start of restructuring and the latter at higher temperatures. The neck growth of adjacent particles was fitted to a surface diffusion sintering model and predicts neck radii as a heating temperature and duration function. Between the temperature range of neck formation and of melting, further restructuring occurred which lead to dissolution of particulate structure and to densification and which resulted in a porous object consisting of straight elongated substructures which connected kinks of higher material density. The thermal transformation is important for the change of strength, collisional behavior, light-scattering properties, and thermal conductivity with relevance to dust aggregates, planetesimals, comets, interplanetary dust particles, and regolith-covered celestial bodies.

Sintering temperature effect of divalent europium ion doped tetra-calcium phosphate phosphors for latent fingerprint detection

NASA Astrophysics Data System (ADS)

Hong, Woo Tae; Park, Jin Young; Je, Jae-Yong; Yang, Hyun Kyoung

2018-07-01

Ca4(PO4)2O:Eu2+ (CPO:Eu2+) phosphors were successfully synthesized by high-energy ball milling. In order to study the effect of sintering temperature, the phosphors were synthesized at various sintering temperatures. The crystal structure of CPO:Eu2+ was determined to be monoclinic P21. Owing to the f-d transitions of the Eu2+ ions in the CPO:Eu2+ phosphors, the PL spectra of the phosphors showed an intense red emission centered at 635 nm with 418 nm excitation. Using high-energy ball milling, a more intense emission (compared to that reported from other research) can be visually observed with human eyes in the form of orange-red light, which is helpful in latent fingerprint detection. In addition, high-temperature sintering results in an increase of the PL intensity owing to the larger particle size and lower levels of impurities in the CPO:Eu2+ phosphors. The latent fingerprint image obtained by using CPO:Eu2+ phosphors reveals a high contrast for various substrate materials, because the phosphors exhibit strong red emission and adhere to the residue of the fingerprint after flowing. On the basis of these results, red-emitting CPO:Eu2+ phosphors can be used for the detection of latent fingerprints in solving criminal cases.

Short communication on " In-situ TEM ion irradiation investigations on U 3Si 2 at LWR temperatures"

DOE PAGES

Miao, Yinbin; Harp, Jason; Mo, Kun; ...

2016-11-21

Here, the radiation-induced amorphization of U 3Si 2 was investigated by in-situ transmission electron microscopy using 1 MeV Kr ion irradiation. Both arc-melted and sintered U3Si2 specimens were irradiated at room temperature to confirm the similarity in their responses to radiation. The sintered specimens were then irradiated at 350 °C and 550 °C up to 7.2 × 10 15 ions/cm 2 to examine their amorphization behavior under light water reactor (LWR) conditions. U 3Si 2 remains crystalline under irradiation at LWR temperatures. Oxidation of the material was observed at high irradiation doses.

Short Communication on "In-situ TEM ion irradiation investigations on U3Si2 at LWR temperatures"

NASA Astrophysics Data System (ADS)

Miao, Yinbin; Harp, Jason; Mo, Kun; Bhattacharya, Sumit; Baldo, Peter; Yacout, Abdellatif M.

2017-02-01

The radiation-induced amorphization of U3Si2 was investigated by in-situ transmission electron microscopy using 1 MeV Kr ion irradiation. Both arc-melted and sintered U3Si2 specimens were irradiated at room temperature to confirm the similarity in their responses to radiation. The sintered specimens were then irradiated at 350 °C and 550 °C up to 7.2 × 1015 ions/cm2 to examine their amorphization behavior under light water reactor (LWR) conditions. U3Si2 remains crystalline under irradiation at LWR temperatures. Oxidation of the material was observed at high irradiation doses.

Portable flash lamp reflectance analyzer system and method

NASA Technical Reports Server (NTRS)

Kalshoven, James Edward (Inventor)

1999-01-01

The system and method allow spectroscopic analysis of vegetation or the like without effects from changing sun and cloud conditions, undesired portions of the area of interest or atmospheric disturbances. The system (1) includes a light source (5) such as a xenon flash lamp, a telescope (7), a spectrometer (9), an analog/digital converter (11), a memory (13), a display (15), and an on-board microprocessor (17) or a port (19) for attachment to a laptop computer. The system is taken to an area of interest in the woods (step 41), the vegetation is illuminated from below (step 43) and data are taken (step 45).

Generalizing the flash technique in the front-face configuration to measure the thermal diffusivity of semitransparent solids

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

Pech-May, Nelson Wilbur; Department of Applied Physics, CINVESTAV Unidad Mérida, carretera Antigua a Progreso km6, A.P. 73 Cordemex, Mérida Yucatán 97310, México; Mendioroz, Arantza

2014-10-15

In this work, we have extended the front-face flash method to retrieve simultaneously the thermal diffusivity and the optical absorption coefficient of semitransparent plates. A complete theoretical model that allows calculating the front surface temperature rise of the sample has been developed. It takes into consideration additional effects, such as multiple reflections of the heating light beam inside the sample, heat losses by convection and radiation, transparency of the sample to infrared wavelengths, and heating pulse duration. Measurements performed on calibrated solids, covering a wide range of absorption coefficients (from transparent to opaque) and thermal diffusivities, validate the proposed method.

Measurement of activation of rhodopsine with heavy ions irradiation in the ALTEA program: a possible mechanism responsible for light flash perceptions in space

NASA Astrophysics Data System (ADS)

Narici, Livio; Rinaldi, Adele; Sannita, Walter, , Prof; Paci, Maurizio; Brunetti, Valentina; de Martino, Angelo; Picozza, Piergiorgio

Since late 60s astronauts in space have reported seeing flashes of light, more frequently when dark adapted. Experiments have been performed to characterize these phenomena, and to suggest possible mechanisms. High Z ions have been shown to be the most likely cause of these perceptions: when ionizing radiation hits the eye there is a high probability of a light flash perception. However the mechanisms behind this phenomenon are not fully understood yet. We show that one of these mechanisms is the activation of the rhodopsin (bleaching) by heavy ions. Rhodopsin is at the start of the photo-electronic cascade in the process of vision. It is one of the best molecular transducer to convert a visible photon into an electric signal. In this work we show that rhodopsine can also be activated by irradiation with 12C nuclei. In the frame of ALTEA program, aimed at studying the effects of cosmic radiation on brain functions, an investigation on the interaction between heavy ions and rhodopsin has been performed. Intact Rod Outer Segment (ROS) containing rhodopsin were isolated from bovine retina. Suspended rods were irradiated with 12C (200 MeV/n, well below the Cherenkov threshold) at GSI (Darmstadt FRG) with doses ranging from few mrem to several rem. Spectrophotometric measurements investigated the presence of non activated and activated rhodopsin. The functionality of the purified rods were checked by previous light irradiation and subsequent regeneration by the addition of external 11-cis-retinal, to confirm the reversibility of the process in vitro. We can show effective and reversible bleaching also following irradiation, thus proving that the rhodopsin was not damaged by radiation. Works are in progress to model this interaction. Latest analysis results and considerations about the underlying mechanism will be presented.

78 FR 29094 - Safety Zone; Coronado Fourth of July Fireworks, Glorietta Bay; Coronado, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-17

... waterways, darkness punctuated by bright flashes of light and burning debris has the potential to result in...: The safety zone will only be in effect for one hour, late in the evening when vessel traffic is low...

Spark Generated by ChemCam Laser During Tests

NASA Image and Video Library

2010-09-21

The ChemCam instrument for NASA Mars Science Laboratory mission uses a pulsed laser beam to vaporize a pinhead-size target, producing a flash of light from the ionized material plasma that can be analyzed to identify chemical elements in the target.

Color defective vision and the recognition of aviation color signal light flashes.

DOT National Transportation Integrated Search

1971-06-01

A previous study reported on the efficiency with which various tests of color defective vision can predict performance during daylight conditions on a practical test of ability to discriminate aviation signal red, white, and green. In the current stu...

Annual Summary Report, 15 June 1960-14 June 1961,

DTIC Science & Technology

The habituation and the dishabituation of the visual responses to repetitive light flashes were investigated in the cerveau isole cat. The...system show that EEG synchronization increases following bilateral withdrawal of the retinal dark discharge in the cerveau isole cat, and following

Preliminary analysis of LED enhanced signs at a passive rural level crossing

DOT National Transportation Integrated Search

2015-03-23

The purpose of this research was to measure motor vehicle speed profiles at a rural level crossing following the replacement of the existing Crossbuck signs and Advance Warning signs (AWSs) with flashing light-emitting diode (LED) versions. Measureme...

Open-source products for a lighting experiment device.

PubMed

Gildea, Kevin M; Milburn, Nelda

2014-12-01

The capabilities of open-source software and microcontrollers were used to construct a device for controlled lighting experiments. The device was designed to ascertain whether individuals with certain color vision deficiencies were able to discriminate between the red and white lights in fielded systems on the basis of luminous intensity. The device provided the ability to control the timing and duration of light-emitting diode (LED) and incandescent light stimulus presentations, to present the experimental sequence and verbal instructions automatically, to adjust LED and incandescent luminous intensity, and to display LED and incandescent lights with various spectral emissions. The lighting device could easily be adapted for experiments involving flashing or timed presentations of colored lights, or the components could be expanded to study areas such as threshold light perception and visual alerting systems.

A Purkinje shift in the spectral sensitivity of grey squirrels

PubMed Central

Silver, Priscilla H.

1966-01-01

1. The light-adapted spectral sensitivity of the grey squirrel has been determined by an automated training method at a level about 6 log units above the squirrel's absolute threshold. 2. The maximum sensitivity is near 555 nm, under light-adapted conditions, compared with the dark-adapted maximum near 500 nm found by a similar method. 3. Neither the light-adapted nor the dark-adapted behavioural threshold agrees with electrophysiological findings using single flash techniques, but there is agreement with e.r.g. results obtained with sinusoidal stimuli. PMID:5972118

Bioluminescence of Marine Dinoflagellates

PubMed Central

Seliger, H. H.; Fastie, W. G.; Taylor, W. R.; McElroy, W. D.

1962-01-01

Portable light-baffled underwater photometers have been designed for the measurement of dinoflagellate bioluminescence by day and night. Maximal light emission is obtained by mechanical stimulation in a defined volume. The pump which stimulates the dinoflagellates also constantly replenishes the sample volume so that continuous measurements are possible. Evidence for both diurnal variation and vertical migration is presented. Using luminous bacteria for calibration a single dinoflagellate has been found to emit of the order of 1010 light quanta per flash. The technique suggests that large scale mapping of bioluminescence is feasible. PMID:19873546

The Pupil Light Reflex in Leber's Hereditary Optic Neuropathy: Evidence for Preservation of Melanopsin-Expressing Retinal Ganglion Cells

PubMed Central

Moura, Ana Laura A.; Nagy, Balázs V.; La Morgia, Chiara; Barboni, Piero; Oliveira, André Gustavo Fernandes; Salomão, Solange R.; Berezovsky, Adriana; de Moraes-Filho, Milton Nunes; Chicani, Carlos Filipe; Belfort, Rubens; Carelli, Valerio; Sadun, Alfredo A.; Hood, Donald C.; Ventura, Dora Fix

2013-01-01

Purpose. To investigate the pupillary light reflex (PLR) of patients with severe loss of vision due to Leber's Hereditary Optic Neuropathy (LHON) in the context of a proposed preservation of melanopsin-expressing retinal ganglion cells (mRGCs). Methods. Ten LHON patients (7 males; 51.6 ± 14.1 years), with visual acuities ranging from 20/400 to hand motion perception and severe visual field losses, were tested and compared with 16 healthy subjects (7 males; 42.15 ± 15.4 years) tested as controls. PLR was measured with an eye tracker and the stimuli were controlled with a Ganzfeld system. Pupil responses were measured monocularly, to 1 second of blue (470 nm) and red (640 nm) flashes with 1, 10, 100, and 250 cd/m2 luminances. The normalized amplitude of peak of the transient PLR and the amplitude of the sustained PLR at 6 seconds after the flash offset were measured. In addition, optical coherence topography (OCT) scans of the peripapillary retinal nerve fiber layer were obtained. Results. The patient's peak PLR responses were on average 15% smaller than controls (P < 0.05), but 5 out of 10 patients had amplitudes within the range of controls. The patients' sustained PLRs were comparable with controls at lower flash intensities, but on average, 27% smaller to the 250 cd/m2 blue light, although there was considerable overlap with the PLR amplitudes of control. All patients had severe visual field losses and the retinal nerve fiber layer thickness was reduced to a minimum around the optic disc in 8 of the 10 patients. Conclusions. The PLR is maintained overall in LHON patients despite the severity of optic atrophy. These results are consistent with previous evidence of selective preservation of mRGCs. PMID:23737476

Retinal cross talk in the mammalian visual system

PubMed Central

Tang, Xiaolan; Tzekov, Radouil

2016-01-01

The existence and functional relevance of efferent optic nerve fibers in mammals have long been debated. While anatomical evidence for cortico-retinal and retino-retinal projections is substantial, physiological evidence is lacking, as efferent fibers are few in number and are severed in studies of excised retinal tissue. Here we show that interocular connections contribute to retinal bioelectrical activity in adult mammals. Full-field flash electroretinograms (ERGs) were recorded from one or both eyes of Brown-Norway rats under dark-adapted (n = 16) and light-adapted (n = 11) conditions. Flashes were confined to each eye by an opaque tube that blocked stray light. Monocular flashes evoked a small (5–15 μV) signal in the nonilluminated eye, which was named “crossed ERG” (xERG). The xERG began under dark-adapted conditions with a positive (xP1) wave that peaked at 70–90 ms and ended with slower negative (xN1) and positive (xP2) waves from 200 to 400 ms. xN1 was absent under light-adapted conditions. Injection of tetrodotoxin in either eye (n = 15) eliminated the xERG. Intraocular pressure elevation of the illuminated eye (n = 6) had the same effect. The treatments also altered the ERG b-wave in both eyes, and the alterations correlated with xERG disappearance. Optic nerve stimulation (n = 3) elicited a biphasic compound action potential in the nonstimulated nerve with 10- to 13-ms latency, implying that the xERG comes from slow-conducting (W type) fibers. Monocular dye application (n = 7) confirmed the presence of retino-retinal ganglion cells in adult rats. We conclude that mammalian eyes communicate directly with each other via a handful of optic nerve fibers. The cross talk alters retinal activity in rats, and perhaps other animals. PMID:26984426

Modulation of cardiac tissue electrophysiological properties with light-sensitive proteins.

PubMed

Nussinovitch, Udi; Shinnawi, Rami; Gepstein, Lior

2014-04-01

Optogenetics approaches, utilizing light-sensitive proteins, have emerged as unique experimental paradigms to modulate neuronal excitability. We aimed to evaluate whether a similar strategy could be used to control cardiac-tissue excitability. A combined cell and gene therapy strategy was developed in which fibroblasts were transfected to express the light-activated depolarizing channel Channelrhodopsin-2 (ChR2). Patch-clamp studies confirmed the development of a robust inward current in the engineered fibroblasts following monochromatic blue-light exposure. The engineered cells were co-cultured with neonatal rat cardiomyocytes (or human embryonic stem cell-derived cardiomyocytes) and studied using a multielectrode array mapping technique. These studies revealed the ability of the ChR2-fibroblasts to electrically couple and pace the cardiomyocyte cultures at varying frequencies in response to blue-light flashes. Activation mapping pinpointed the source of this electrical activity to the engineered cells. Similarly, diffuse seeding of the ChR2-fibroblasts allowed multisite optogenetics pacing of the co-cultures, significantly shortening their electrical activation time and synchronizing contraction. Next, optogenetics pacing in an in vitro model of conduction block allowed the resynchronization of the tissue's electrical activity. Finally, the ChR2-fibroblasts were transfected to also express the light-sensitive hyperpolarizing proton pump Archaerhodopsin-T (Arch-T). Seeding of the ChR2/ArchT-fibroblasts allowed to either optogentically pace the cultures (in response to blue-light flashes) or completely suppress the cultures' electrical activity (following continuous illumination with 624 nm monochromatic light, activating ArchT). The results of this proof-of-concept study highlight the unique potential of optogenetics for future biological pacemaking and resynchronization therapy applications and for the development of novel anti-arrhythmic strategies.

Light-induced structural changes and the site of O=O bond formation in PSII caught by XFEL.

PubMed

Suga, Michihiro; Akita, Fusamichi; Sugahara, Michihiro; Kubo, Minoru; Nakajima, Yoshiki; Nakane, Takanori; Yamashita, Keitaro; Umena, Yasufumi; Nakabayashi, Makoto; Yamane, Takahiro; Nakano, Takamitsu; Suzuki, Mamoru; Masuda, Tetsuya; Inoue, Shigeyuki; Kimura, Tetsunari; Nomura, Takashi; Yonekura, Shinichiro; Yu, Long-Jiang; Sakamoto, Tomohiro; Motomura, Taiki; Chen, Jing-Hua; Kato, Yuki; Noguchi, Takumi; Tono, Kensuke; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Nango, Eriko; Tanaka, Rie; Naitow, Hisashi; Matsuura, Yoshinori; Yamashita, Ayumi; Yamamoto, Masaki; Nureki, Osamu; Yabashi, Makina; Ishikawa, Tetsuya; Iwata, So; Shen, Jian-Ren

2017-03-02

Photosystem II (PSII) is a huge membrane-protein complex consisting of 20 different subunits with a total molecular mass of 350 kDa for a monomer. It catalyses light-driven water oxidation at its catalytic centre, the oxygen-evolving complex (OEC). The structure of PSII has been analysed at 1.9 Å resolution by synchrotron radiation X-rays, which revealed that the OEC is a Mn 4 CaO 5 cluster organized in an asymmetric, 'distorted-chair' form. This structure was further analysed with femtosecond X-ray free electron lasers (XFEL), providing the 'radiation damage-free' structure. The mechanism of O=O bond formation, however, remains obscure owing to the lack of intermediate-state structures. Here we describe the structural changes in PSII induced by two-flash illumination at room temperature at a resolution of 2.35 Å using time-resolved serial femtosecond crystallography with an XFEL provided by the SPring-8 ångström compact free-electron laser. An isomorphous difference Fourier map between the two-flash and dark-adapted states revealed two areas of apparent changes: around the Q B /non-haem iron and the Mn 4 CaO 5 cluster. The changes around the Q B /non-haem iron region reflected the electron and proton transfers induced by the two-flash illumination. In the region around the OEC, a water molecule located 3.5 Å from the Mn 4 CaO 5 cluster disappeared from the map upon two-flash illumination. This reduced the distance between another water molecule and the oxygen atom O4, suggesting that proton transfer also occurred. Importantly, the two-flash-minus-dark isomorphous difference Fourier map showed an apparent positive peak around O5, a unique μ 4 -oxo-bridge located in the quasi-centre of Mn1 and Mn4 (refs 4,5). This suggests the insertion of a new oxygen atom (O6) close to O5, providing an O=O distance of 1.5 Å between these two oxygen atoms. This provides a mechanism for the O=O bond formation consistent with that proposed previously.

A Self-consistent Model for a Full Cycle of Recurrent Novae—Wind Mass-loss Rate and X-Ray Luminosity

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

Kato, Mariko; Saio, Hideyuki; Hachisu, Izumi, E-mail: mariko.kato@hc.st.keio.ac.jp

2017-04-01

An unexpectedly slow evolution in the pre-optical-maximum phase was suggested in the very short recurrence period of nova M31N 2008-12a. To obtain reasonable nova light curves we have improved our calculation method by consistently combining optically thick wind solutions of hydrogen-rich envelopes with white dwarf (WD) structures calculated by a Henyey-type evolution code. The wind mass-loss rate is properly determined with high accuracy. We have calculated light curve models for 1.2 M {sub ⊙} and 1.38 M {sub ⊙} WDs with mass accretion rates corresponding to recurrence periods of 10 yr and 1 yr, respectively. The outburst lasts 590/29 days,more » in which the pre-optical-maximum phase is 82/16 days, for 1.2/1.38 M {sub ⊙}, respectively. Optically thick winds start at the end of the X-ray flash and cease at the beginning of the supersoft X-ray phase. We also present supersoft X-ray light curves including a prompt X-ray flash and later supersoft X-ray phase.« less

[Evaluation of alumina effects on the mechanical property and translucency of nano-zirconia all-ceramics].

PubMed

Jiang, Li; Zhao, Yong-qi; Zhang, Jing-chao; Liao, Yun-mao; Li, Wei

2010-06-01

To study the effects of alumina content on sintered density, mechanical property and translucency of zirconia nanocomposite all-ceramics. Specimens of zirconia nanocomposite all-ceramics were divided into five groups based on their alumina content which are 0% (control group), 2.5%, 5.0%, 7.5% and 10.0% respectively. The sintered densities were measured using Archimedes' method. Specimens' bending strengths were measured with three-point bending test (ISO 6872). The visible light transmittances were measured with spectrophotometric arrangements and the fractured surfaces were observed using scanning electron microscope (SEM). The control group of pure zirconia could be sintered to the theoretical density under pressure-less sintering condition. The bending strength was (1100.27 ± 54.82) MPa, the fracture toughness was (4.96 ± 0.35) MPa×m(1/2) and the transmittance could reach 17.03%. The sintered density and transmittance decreased as alumina content increased from 2.5% to 10%. However, the fracture toughness only increased slightly. In all four alumina groups, the additions of alumina had no significant effect on samples' bending strengths (P > 0.05). When the content of alumina was 10%, fracture toughness of specimens reached (6.13 ± 0.44) MPa×m(1/2) while samples' transmittance declined to 6.21%. SEM results showed that alumina particles had no significant effect on the grain size and distribution of tetragonal zirconia polycrystals. Additions of alumina to yttria-tetragonal zirconia polycrystals could influence its mechanical property and translucency. Additions of the other phase to zirconia ceramics should meet the clinical demands of strength and esthetics.

Color defective vision and day and night recognition of aviation color signal light flashes.

DOT National Transportation Integrated Search

1971-07-01

A previous study reported on the efficiency with which various tests of color defective vision can predict performance during daylight conditions on a practical test of ability to discriminate aviation signal red, white, and green. In the current stu...

Viewing Spark Generated by ChemCam Laser for Mars Rover

NASA Image and Video Library

2010-09-21

The ChemCam instrument for NASA Mars Science Laboratory mission uses a pulsed laser beam to vaporize a pinhead-size target, producing a flash of light from the ionized material plasma that can be analyzed to identify chemical elements in the target.

Performance assessment of an onboard monitoring system for CMV drivers : a field operational test : research brief.

DOT National Transportation Integrated Search

2016-11-01

The primary goal of an onboard monitoring system (OBMS) is to enhance driver performance and safety. OBMSs are employed with the expectation that feedback provided concurrently (via flashing feedback lights in the vehicle) and cumulatively (via coach...

Interior detail, building 810, view to north showing curved chord ...

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

Interior detail, building 810, view to north showing curved chord sections of roof trusses, 90mm lens plus electronic flash fill lighting. - Travis Air Force Base, B-36 Hangar, Between Woodskill Avenue & Ellis, adjacent to Taxiway V & W, Fairfield, Solano County, CA

Washington coast meteorite

NASA Astrophysics Data System (ADS)

Kacerek, Richard

2018-02-01

Public reports about a bright flash of light, sonic booms and some shaking of the ground could be associated with a giant dust cloud registered on a Doppler radar image, indicating an explosion of a bolide about 20 miles off the coast followed by an impact in the ocean.

Radiation Chemistry in Organized Assemblies.

ERIC Educational Resources Information Center

Thomas, J. K.; Chen, T. S.

1981-01-01

Expands the basic concepts regarding the radiation chemistry of simple aqueous systems to more complex, but well defined, organized assemblies. Discusses the differences in behavior in comparison to simple systems. Reviews these techniques: pulse radiolysis, laser flash, photolysis, and steady state irradiation by gamma rays or light. (CS)

Comparison of the light-flash phenomena observed in space and in laboratory experiments.

PubMed

McNulty, P J; Pease, V P; Bond, V P

1977-01-01

Astronauts on Apollo and Skylab missions have reported observing a variety of visual phenomena when their eyes were closed and adapted to darkness. These observations were studied under controlled conditions during a number of sessions on board Apollo and Skylab spacecraft and the data available to date on these so-called light flashes are in the form of descriptions of the phenomena and frequency of occurrence. Similar visual phenomena have been demonstrated in a number of laboratories by exposing the eyes of human subjects to beams of neutrons, alpha particles, pions and protons. More than one physical mechanism is involved in the laboratory and space phenomena. No direct comparison of the laboratory and space observations has been made by observers who have experienced both. However, the range of visual phenomena observed in the laboratory is consistent with the Apollo and Skylab observations. Measured detection efficiencies can be used to estimate the frequencies with which various phenomena would be observed if that subject was exposed to cosmic rays in space.

Flame Spread and Damaged Properties of RCD Cases by Tracking

NASA Astrophysics Data System (ADS)

Choi, Chung-Seog; Kim, Hyang-Kon; Shong, Kil-Mok; Kim, Dong-Woo

In this paper, the flame spread and damaged properties of residual current protective devices (RCDs) by tracking were analyzed. Pictures of tracking process were taken by High Speed Imaging System (HSIS), and fire progression was observed by timeframe. During the tracking process of RCD, it seemed to explode just once in appearance, but in the results of HSIS analysis, a small fire broke out and disappeared repeatedly 35 times and a flash of light repeated 15 times. Finally, an explosion with a flash of light occurred and lots of particles were scattered. Electric muffle furnace was used for heat treatment of RCD cases. The surface characteristics of specimens due to heat treatment and tracking deterioration were taken by Scanning Electron Microscope (SEM). Chemical and thermal properties of these deteriorated specimens were analyzed by Fourier Transform Infrared Spectrometer (FT-IR) and Differential Thermal Analyzer (DTA). The carbonization characteristics showed different chemical properties due to energy sources, and the results could be applicable to judge the accident causes.

Variable Message Signs for road tunnel emergency evacuations.

PubMed

Ronchi, Enrico; Nilsson, Daniel; Modig, Henric; Walter, Anders Lindgren

2016-01-01

This paper investigates the design of Variable Message Signs (VMS) as a way-finding aid for road tunnel emergency evacuations. The use of the Theory of Affordances is suggested to provide recommendations on the design of VMS. A preliminary evaluation of 11 selected VMS systems was performed and 6 of them were further evaluated using an affordance-based within subject stated-preference questionnaire administered to a sample of 62 participants. Results are used to provide recommendations on the characteristics of the VMS systems, such as (1) size of the sign (large or small); (2) use of flashing lights; (3) colour scheme; (4) message coding (i.e., text, pictograms or a combination of them). The best performing VMS features for road tunnel emergency evacuation included the use of larger signs, flashing lights, the combination of emergency exit pictorial symbol in green in one panel and text in amber in the other panel. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

The Final Helium Flash Object Sakurai: Photometric Behavior and Physical Characteristics.

NASA Astrophysics Data System (ADS)

Duerbeck, Hilmar W.; Benetti, Stefano; Gautschy, Alfred; van Genderen, Arnout M.; Kemper, Ciska; Liller, William; Thomas, Tom

1997-10-01

Six-color broadband photometry of Sakurai's Object, a star that underwent a final helium flash in late 1994, has been carried out since 1996 February. The light curves show that Sakurai's Object is continuously cooling while it slowly expands and slightly increases its luminosity. The distance is estimated to be 8 kpc, the interstellar extinction EB-V=0.53, and the luminosity in early 1997 is 10 000Lsun. The high luminosity indicates that the white dwarf is quite massive. With the assumption of a slightly accelerated photospheric expansion a realistic description of the outburst light curve is achieved. Superimposed on the gradual brightness changes are variations with amplitudes of up to 0.1 mag and cycle lengths of 63, 23, 14, and 8 days. In spite of the fact that no persistent periodicities could be detected, pulsational studies show that such cyclic changes can be used to constrain stellar parameters such as mass, luminosity, and chemical abundances.

Subretinal electrical stimulation preserves inner retinal function in RCS rat retina.

PubMed

Ciavatta, Vincent T; Mocko, Julie A; Kim, Moon K; Pardue, Machelle T

2013-01-01

Previously, studies showed that subretinal electrical stimulation (SES) from a microphotodiode array (MPA) preserves electroretinography (ERG) b-wave amplitude and regional retinal structure in the Royal College of Surgeons (RCS) rat and simultaneously upregulates Fgf2 expression. This preservation appears to be associated with the increased current produced when the MPA is exposed to ERG test flashes, as weekly ERG testing produces greater neuroprotection than biweekly or no testing. Using an infrared source to stimulate the MPA while avoiding potential confounding effects from exposing the RCS retina to high luminance white light, this study examined whether neuroprotective effects from SES increased with subretinal current in a dose-dependent manner. RCS rats (n=49) underwent subretinal implantation surgery at P21 with MPA devices in one randomly selected eye, and the other eye served as the control. Naïve RCS rats (n=25) were also studied. To increase SES current levels, implanted eyes were exposed to 15 min per session of flashing infrared light (IR) of defined intensity, frequency, and duty cycle. Rats were divided into four SES groups that received ERG testing only (MPA only), about 450 µA/cm2 once per week (Low 1X), about 450 µA/cm2 three times per week (Low 3X), and about 1350 µA/cm2 once per week (High 1X). One eye of the control animals was randomly chosen for IR exposure. All animals were followed for 4 weeks with weekly binocular ERGs. A subset of the eyes was used to measure retina Fgf2 expression with real-time reverse-transcription PCR. Eyes receiving SES showed significant preservation of b-wave amplitude, a- and b-wave implicit times, oscillatory potential amplitudes, and post-receptoral parameters (Vmax and log σ) compared to untreated eyes. All SES-treated eyes had similar preservation, regardless of increased SES from IR light exposure. SES-treated eyes tended to have greater retinal Fgf2 expression than untreated eyes, but Fgf2 expression did not increase with IR light. The larger post-receptoral responses (Vmax), greater post-receptoral sensitivity (logσ), and larger oscillatory potentials suggest SES-treated eyes maintained better inner retinal function than the opposite, untreated eyes. This suggests that in addition to preserving photoreceptors in RCS rats, SES may also promote more robust signal transmission through the retinal network compared to the control eyes. These studies suggest that the protective effects of SES on RCS retinal function cannot be improved with additional subretinal current induction from the MPA, or the charge injection provided by ERG Ganzfeld flashes was not adequately mimicked by the flashing IR light used in this study.

System Would Predictively Preempt Traffic Lights for Emergency Vehicles

NASA Technical Reports Server (NTRS)

Bachelder, Aaron; Foster, Conrad

2004-01-01

Two electronic communication-and-control systems have been proposed as means of modifying the switching of traffic lights to give priority to emergency vehicles. Both systems would utilize the inductive loops already installed in the streets of many municipalities to detect vehicles for timing the switching of traffic lights. The proposed systems could be used alone or to augment other automated emergency traffic-light preemption systems that are already present in some municipalities, including systems that recognize flashing lights or siren sounds or that utilize information on the positions of emergency vehicles derived from the Global Positioning System (GPS). Systems that detect flashing lights and siren sounds are limited in range, cannot "see" or "hear" well around corners, and are highly vulnerable to noise. GPS-based systems are effective in rural areas and small cities, but are often ineffective in large cities because of frequent occultation of GPS satellite signals by large structures. In contrast, the proposed traffic-loop forward prediction system would be relatively invulnerable to noise, would not be subject to significant range limitations, and would function well in large cities -- even in such places as underneath bridges and in tunnels, where GPS-based systems do not work. One proposed system has been characterized as "car-active" because each participating emergency vehicle would be equipped with a computer and a radio transceiver that would communicate with stationary transceivers at the traffic loops. The other proposed system has been characterized as "car-passive" because a passive radio transponder would be installed on the underside of a participating vehicle.

Synthesis and sintering of UN-UO2 fuel composites

NASA Astrophysics Data System (ADS)

Jaques, Brian J.; Watkins, Jennifer; Croteau, Joseph R.; Alanko, Gordon A.; Tyburska-Püschel, Beata; Meyer, Mitch; Xu, Peng; Lahoda, Edward J.; Butt, Darryl P.

2015-11-01

The design and development of an economical, accident tolerant fuel (ATF) for use in the current light water reactor (LWR) fleet is highly desirable for the future of nuclear power. Uranium mononitride has been identified as an alternative fuel with higher uranium density and thermal conductivity when compared to the benchmark, UO2, which could also provide significant economic benefits. However, UN by itself reacts with water at reactor operating temperatures. In order to reduce its reactivity, the addition of UO2 to UN has been suggested. In order to avoid carbon impurities, UN was synthesized from elemental uranium using a hydride-dehydride-nitride thermal synthesis route prior to mixing with up to 10 wt% UO2 in a planetary ball mill. UN and UN - UO2 composite pellets were sintered in Ar - (0-1 at%) N2 to study the effects of nitrogen concentration on the evolved phases and microstructure. UN and UN-UO2 composite pellets were also sintered in Ar - 100 ppm N2 to assess the effects of temperature (1700-2000 °C) on the final grain morphology and phase concentration.

Microstructure and hydrothermal corrosion behavior of NITE-SiC with various sintering additives in LWR coolant environments

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

Parish, Chad M.; Terrani, Kurt A.; Kim, Young -Jin

Nano-infiltration and transient eutectic phase (NITE) sintering was developed for fabrication of nuclear grade SiC composites. We produced monolithic SiC ceramics using NITE sintering, as candidates for accident-tolerant fuels in light-water reactors (LWRs). In this work, we exposed three different NITE chemistries (yttria-alumina [YA], ceria-zirconia-alumina [CZA], and yttria-zirconia-alumina [YZA]) to autoclave conditions simulating LWR coolant loops. The YZA was most corrosion resistant, followed by CZA, with YA being worst. High-resolution elemental analysis using scanning transmission electron microscopy (STEM) X-ray mapping combined with multivariate statistical analysis (MVSA) datamining helped explain the differences in corrosion. YA-NITE lost all Al from the corrodedmore » region and the ytttria reformed into blocky precipitates. The CZA material lost all Al from the corroded area, and the YZA – which suffered the least corrosion –retained some Al in the corroded region. Lastly, the results indicate that the YZA-NITE SiC is most resistant to hydrothermal corrosion in the LWR environment.« less

Moving Stimuli Facilitate Synchronization But Not Temporal Perception

PubMed Central

Silva, Susana; Castro, São Luís

2016-01-01

Recent studies have shown that a moving visual stimulus (e.g., a bouncing ball) facilitates synchronization compared to a static stimulus (e.g., a flashing light), and that it can even be as effective as an auditory beep. We asked a group of participants to perform different tasks with four stimulus types: beeps, siren-like sounds, visual flashes (static) and bouncing balls. First, participants performed synchronization with isochronous sequences (stimulus-guided synchronization), followed by a continuation phase in which the stimulus was internally generated (imagery-guided synchronization). Then they performed a perception task, in which they judged whether the final part of a temporal sequence was compatible with the previous beat structure (stimulus-guided perception). Similar to synchronization, an imagery-guided variant was added, in which sequences contained a gap in between (imagery-guided perception). Balls outperformed flashes and matched beeps (powerful ball effect) in stimulus-guided synchronization but not in perception (stimulus- or imagery-guided). In imagery-guided synchronization, performance accuracy decreased for beeps and balls, but not for flashes and sirens. Our findings suggest that the advantages of moving visual stimuli over static ones are grounded in action rather than perception, and they support the hypothesis that the sensorimotor coupling mechanisms for auditory (beeps) and moving visual stimuli (bouncing balls) overlap. PMID:27909419

Moving Stimuli Facilitate Synchronization But Not Temporal Perception.

PubMed

Silva, Susana; Castro, São Luís

2016-01-01

Recent studies have shown that a moving visual stimulus (e.g., a bouncing ball) facilitates synchronization compared to a static stimulus (e.g., a flashing light), and that it can even be as effective as an auditory beep. We asked a group of participants to perform different tasks with four stimulus types: beeps, siren-like sounds, visual flashes (static) and bouncing balls. First, participants performed synchronization with isochronous sequences (stimulus-guided synchronization), followed by a continuation phase in which the stimulus was internally generated (imagery-guided synchronization). Then they performed a perception task, in which they judged whether the final part of a temporal sequence was compatible with the previous beat structure (stimulus-guided perception). Similar to synchronization, an imagery-guided variant was added, in which sequences contained a gap in between (imagery-guided perception). Balls outperformed flashes and matched beeps (powerful ball effect) in stimulus-guided synchronization but not in perception (stimulus- or imagery-guided). In imagery-guided synchronization, performance accuracy decreased for beeps and balls, but not for flashes and sirens. Our findings suggest that the advantages of moving visual stimuli over static ones are grounded in action rather than perception, and they support the hypothesis that the sensorimotor coupling mechanisms for auditory (beeps) and moving visual stimuli (bouncing balls) overlap.

How does the blue-ringed octopus (Hapalochlaena lunulata) flash its blue rings?

PubMed

Mäthger, Lydia M; Bell, George R R; Kuzirian, Alan M; Allen, Justine J; Hanlon, Roger T

2012-11-01

The blue-ringed octopus (Hapalochlaena lunulata), one of the world's most venomous animals, has long captivated and endangered a large audience: children playing at the beach, divers turning over rocks, and biologists researching neurotoxins. These small animals spend much of their time in hiding, showing effective camouflage patterns. When disturbed, the octopus will flash around 60 iridescent blue rings and, when strongly harassed, bite and deliver a neurotoxin that can kill a human. Here, we describe the flashing mechanism and optical properties of these rings. The rings contain physiologically inert multilayer reflectors, arranged to reflect blue-green light in a broad viewing direction. Dark pigmented chromatophores are found beneath and around each ring to enhance contrast. No chromatophores are above the ring; this is unusual for cephalopods, which typically use chromatophores to cover or spectrally modify iridescence. The fast flashes are achieved using muscles under direct neural control. The ring is hidden by contraction of muscles above the iridophores; relaxation of these muscles and contraction of muscles outside the ring expose the iridescence. This mechanism of producing iridescent signals has not previously been reported in cephalopods and we suggest that it is an exceptionally effective way to create a fast and conspicuous warning display.

Comparisons of GLM and LMA Observations

NASA Astrophysics Data System (ADS)

Thomas, R. J.; Krehbiel, P. R.; Rison, W.; Stanley, M. A.; Attanasio, A.

2017-12-01

Observations from 3-dimensional VHF lightning mapping arrays (LMAs) provide a valuable basis for evaluating the spatial accuracy and detection efficiencies of observations from the recently launched, optical-based Geosynchronous Lightning Mapper (GLM). In this presentation, we describe results of comparing the LMA and GLM observations. First, the observations are compared spatially and temporally at the individual event (pixel) level for sets of individual discharges. For LMA networks in Florida, Colorado, and Oklahoma, the GLM observations are well correlated time-wise with LMA observations but are systematically offset by one- to two pixels ( 10 to 15 or 20 km) in a southwesterly direction from the actual lightning activity. The graphical comparisons show a similar location uncertainty depending on the altitude at which the scattered light is emitted from the parent cloud, due to being observed at slant ranges. Detection efficiencies (DEs) can be accurately determined graphically for intervals where individual flashes in a storm are resolved time-wise, and DEs and false alarm rates can be automated using flash sorting algorithms for overall and/or larger storms. This can be done as a function of flash size and duration, and generally shows high detection rates for larger flashes. Preliminary results during the May 1 2017 ER-2 overflight of Colorado storms indicate decreased detection efficiency if the storm is obscured by an overlying cloud layer.

Light transmission and preference of eye patches for occlusion treatment.

PubMed

Heo, Hwan; Park, Jung Won; Park, Sang Woo

2013-01-01

To investigate light transmission and preference for six eye patches for occlusion therapy. Six patches were examined, including; Ortopad Fun Pack, Ortopad Flesh, Kawamoto A-1, Kawamoto A-2, 3M Opticlude, and Everade Eye Guard. The size and the presence of a light blocking pad of patches were investigated. The amount of light transmitted through the patches was evaluated, using a digital light meter and a model eye, in three different environments; indoors with fluorescent light, outdoors on a sunny day, and strong light from illuminator. After patching the normal eye, the flash visual evoked potential (VEP) was measured. Thirty patients with amblyopia or horizontal strabismus, who received occlusion therapy as initial treatment, were included. After using all six patches, patients completed a 7-item questionnaire regarding the patch preference for size, color and shape, adhesive power, pain with removal, skin irritation after removing patch, parent's preference and overall opinion. All patches had a light-blocking pad, except the 3M Nexcare. Ortopad had the strongest light blocking power in the three environments, and the 3M Nexcare had the weakest power. In flash VEP, Ortopad and Kawamoto patches showed flat, but 3M Nexcare and Everade Eye Guard showed normal response. There were significant preferential differences among the patches in all the items of the questionnaire (P<0.05). In comparison between the patches respectively, 3M Nexcare received the lowest satisfaction in pain when removing a patch and skin irritation after removing a patch. Kawamoto A-2 received the lowest score in the overall satisfaction. We found differences in the light-blocking power and in the preference of the various patches for the occlusion treatment. This is a pilot study regarding only characteristics and preferences of patches. Further clinical studies regarding the relationship between characteristics or preferences of patches and outcomes of occlusion treatment are needed.

An Evaluation of the Gap Sizes of 3-Unit Fixed Dental Prostheses Milled from Sintering Metal Blocks.

PubMed

Jung, Jae-Kwan

2017-01-01

This study assessed the clinical acceptability of sintering metal-fabricated 3-unit fixed dental prostheses (FDPs) based on gap sizes. Ten specimens were prepared on research models by milling sintering metal blocks or by the lost-wax technique (LWC group). Gap sizes were assessed at 12 points per abutment (premolar and molar), 24 points per specimen (480 points in a total in 20 specimens). The measured points were categorized as marginal, axial wall, and occlusal for assessment in a silicone replica. The silicone replica was cut through the mesiodistal and buccolingual center. The four sections were magnified at 160x, and the thickness of the light body silicone was measured to determine the gap size, and gap size means were compared. For the premolar part, the mean (standard deviation) gap size was nonsignificantly ( p = 0.139) smaller in the SMB group (68.6 ± 35.6  μ m) than in the LWC group (69.6 ± 16.9  μ m). The mean molar gap was nonsignificantly smaller ( p = 0.852) in the LWC (73.9 ± 25.6  μ m) than in the SMB (78.1 ± 37.4  μ m) group. The gap sizes were similar between the two groups. Because the gap sizes were within the previously proposed clinically accepted limit, FDPs prepared by sintered metal block milling are clinically acceptable.

An Evaluation of the Gap Sizes of 3-Unit Fixed Dental Prostheses Milled from Sintering Metal Blocks

PubMed Central

2017-01-01

This study assessed the clinical acceptability of sintering metal-fabricated 3-unit fixed dental prostheses (FDPs) based on gap sizes. Ten specimens were prepared on research models by milling sintering metal blocks or by the lost-wax technique (LWC group). Gap sizes were assessed at 12 points per abutment (premolar and molar), 24 points per specimen (480 points in a total in 20 specimens). The measured points were categorized as marginal, axial wall, and occlusal for assessment in a silicone replica. The silicone replica was cut through the mesiodistal and buccolingual center. The four sections were magnified at 160x, and the thickness of the light body silicone was measured to determine the gap size, and gap size means were compared. For the premolar part, the mean (standard deviation) gap size was nonsignificantly (p = 0.139) smaller in the SMB group (68.6 ± 35.6 μm) than in the LWC group (69.6 ± 16.9 μm). The mean molar gap was nonsignificantly smaller (p = 0.852) in the LWC (73.9 ± 25.6 μm) than in the SMB (78.1 ± 37.4 μm) group. The gap sizes were similar between the two groups. Because the gap sizes were within the previously proposed clinically accepted limit, FDPs prepared by sintered metal block milling are clinically acceptable. PMID:28246605

Use of police in work zones on highways in Virginia.

DOT National Transportation Integrated Search

2003-01-01

It is generally accepted that one of the most effective ways of controlling speed in a work zone is to have a staffed police car positioned at the beginning of the work zone with its lights flashing and radar on. Drivers detect the presence of police...

45 CFR 3.21 - Emergency vehicles.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 45 Public Welfare 1 2013-10-01 2013-10-01 false Emergency vehicles. 3.21 Section 3.21 Public... THE NATIONAL INSTITUTES OF HEALTH FEDERAL ENCLAVE Traffic Regulations § 3.21 Emergency vehicles. A person must yield the right of way to an emergency vehicle operating its siren or flashing lights. ...

45 CFR 3.21 - Emergency vehicles.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 45 Public Welfare 1 2012-10-01 2012-10-01 false Emergency vehicles. 3.21 Section 3.21 Public... THE NATIONAL INSTITUTES OF HEALTH FEDERAL ENCLAVE Traffic Regulations § 3.21 Emergency vehicles. A person must yield the right of way to an emergency vehicle operating its siren or flashing lights. ...

45 CFR 3.21 - Emergency vehicles.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 45 Public Welfare 1 2011-10-01 2011-10-01 false Emergency vehicles. 3.21 Section 3.21 Public... THE NATIONAL INSTITUTES OF HEALTH FEDERAL ENCLAVE Traffic Regulations § 3.21 Emergency vehicles. A person must yield the right of way to an emergency vehicle operating its siren or flashing lights. ...

45 CFR 3.21 - Emergency vehicles.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 45 Public Welfare 1 2014-10-01 2014-10-01 false Emergency vehicles. 3.21 Section 3.21 Public... THE NATIONAL INSTITUTES OF HEALTH FEDERAL ENCLAVE Traffic Regulations § 3.21 Emergency vehicles. A person must yield the right of way to an emergency vehicle operating its siren or flashing lights. ...

46 CFR 161.013-7 - Signal requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 6 2010-10-01 2010-10-01 false Signal requirements. 161.013-7 Section 161.013-7...: SPECIFICATIONS AND APPROVAL ELECTRICAL EQUIPMENT Electric Distress Light for Boats § 161.013-7 Signal... each S-O-S signal must have a duration of 3 seconds. (b) The flash characteristics described in...

46 CFR 161.013-7 - Signal requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 6 2011-10-01 2011-10-01 false Signal requirements. 161.013-7 Section 161.013-7...: SPECIFICATIONS AND APPROVAL ELECTRICAL EQUIPMENT Electric Distress Light for Boats § 161.013-7 Signal... each S-O-S signal must have a duration of 3 seconds. (b) The flash characteristics described in...

PBF (PER620) interior, basement level. Concrete wall shows outline of ...

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

PBF (PER-620) interior, basement level. Concrete wall shows outline of reactor basin. Sign says, "Flashing Light - Reactor On - Evacuate Area." Date: May 2004. INEEL negative no. HD-41-5-3 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

ScienceCasts: A Display of Lights Above the Storm

NASA Image and Video Library

2017-10-10

Transient Luminous Events (TLEs) are flashes and glows that appear above storms and are results of activity occurring in and below those storms. Researchers are working to better understand lightning and thunderstorms, how they form and develop over time, and why storms produce different TLEs in different circumstances.

77 FR 55829 - Western Area Power Administration; Grapevine Canyon Wind Project Record of Decision (DOE/EIS-0427)

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-11

... megawatts of electricity from wind turbine generators (WTGs). The proposed project includes a wind energy... about the installation of red flashing lights on wind turbine generators per Federal Aviation... DEPARTMENT OF ENERGY Western Area Power Administration; Grapevine Canyon Wind Project Record of...

27. Graffiti in north cells: 'When the golden sun has ...

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

27. Graffiti in north cells: 'When the golden sun has sunk beyond the desert horizon, and darkness followed, under a dim light casting my lonesome heart.'; 135mm lens with electronic flash illumination. - Tule Lake Project Jail, Post Mile 44.85, State Route 139, Newell, Modoc County, CA

46 CFR 161.013-7 - Signal requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 6 2012-10-01 2012-10-01 false Signal requirements. 161.013-7 Section 161.013-7...: SPECIFICATIONS AND APPROVAL ELECTRICAL EQUIPMENT Electric Distress Light for Boats § 161.013-7 Signal... each S-O-S signal must have a duration of 3 seconds. (b) The flash characteristics described in...

46 CFR 161.013-7 - Signal requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 6 2014-10-01 2014-10-01 false Signal requirements. 161.013-7 Section 161.013-7...: SPECIFICATIONS AND APPROVAL ELECTRICAL EQUIPMENT Electric Distress Light for Boats § 161.013-7 Signal... each S-O-S signal must have a duration of 3 seconds. (b) The flash characteristics described in...

46 CFR 161.013-7 - Signal requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 6 2013-10-01 2013-10-01 false Signal requirements. 161.013-7 Section 161.013-7...: SPECIFICATIONS AND APPROVAL ELECTRICAL EQUIPMENT Electric Distress Light for Boats § 161.013-7 Signal... each S-O-S signal must have a duration of 3 seconds. (b) The flash characteristics described in...

Questions Students Ask: The Red-Eye Effect.

ERIC Educational Resources Information Center

Physics Teacher, 1985

1985-01-01

Addresses the question of why a dog's eyes appear red and glow when a flash photograph is taken. Conditions for the red-eye effect, light paths involved, structure of the eye, and typical cameras and lenses are discussed. Also notes differences between the eyes of nocturnal animals and humans. (JN)

LDEF active optical system components experiment

NASA Technical Reports Server (NTRS)

Blue, M. D.

1992-01-01

A preliminary report on the Active Optical System Components Experiment is presented. This experiment contained 136 components in a six inch deep tray including lasers, infrared detectors and arrays, ultraviolet light detectors, light-emitting diodes, a light modulator, flash lamps, optical filters, glasses, and samples of surface finishes. Thermal, mechanical, and structural considerations leading to the design of the tray hardware are discussed. In general, changes in the retested component characteristics appear as much related to the passage of time as to the effects of the space environment, but organic materials, multilayer optical interference filters, and extreme-infrared reflectivity of black paints show unexpected changes.

Smartphone based point-of-care detector of urine albumin

NASA Astrophysics Data System (ADS)

Cmiel, Vratislav; Svoboda, Ondrej; Koscova, Pavlina; Provaznik, Ivo

2016-03-01

Albumin plays an important role in human body. Its changed level in urine may indicate serious kidney disorders. We present a new point-of-care solution for sensitive detection of urine albumin - the miniature optical adapter for iPhone with in-built optical filters and a sample slot. The adapter exploits smart-phone flash to generate excitation light and camera to measure the level of emitted light. Albumin Blue 580 is used as albumin reagent. The proposed light-weight adapter can be produced at low cost using a 3D printer. Thus, the miniaturized detector is easy to use out of lab.

Characteristics of lightning flashes generating sprites above thunderstorms

NASA Astrophysics Data System (ADS)

Soula, S.; Van Der Velde, O. A.; Montanya, J.; Fullekrug, M.; Mlynarczyk, J.

2016-12-01

Sprites are Transient Luminous Events (TLEs) consisting of streamer discharges, in response to a strong transient electrostatic field that exceeds the threshold for dielectric breakdown in the mesosphere. A large panel of sprite observations have been made with several low-light video cameras located in southern France, especially at Pic du Midi (2877 m) in the Pyrénées mountain range. The optical detection of these luminous events allow to determine some of their characteristics as the timing, the duration, the location, the size, the shape, the luminosity. Other parameters describing the storm and the lightning activity provided by different instruments are associated to the sprite observations to a better understanding of their conditions of production and their characteristic settings: (i) the sprites are essentially produced above the stratiform region of the Mesoscale Convective Systems during positive cloud-to-ground lightning flashes that produce large Charge Moment Change (CMC) and with a delay of as much shorter than the current is large. (ii) The long time delayed sprites are associated with continuing current and large CMC. (iii) The sprite elements can be shifted from the stroke location when their delay is long. (iv) Very luminous sprites can produce large current signatures visible in ELF radiation a few milliseconds (< 5 ms) after the positive strokes that generate them, but sometimes imbedded in that of the stroke pulse. (v) Several cases of "dancing sprites" show the successive light emissions reflect the timing and the location of the strokes of the lightning flashes that generate them.

Patterned light flash evoked short latency activity in the visual system of visually normal and in amblyopic subjects.

PubMed

Sjöström, A; Abrahamsson, M

1994-04-01

In a previous experimental study on anaesthetized cat it was shown that a short latency (35-40 ms) cortical potential changed polarity due to the presence or absence of a pattern in the flash stimulus. The results suggested one pathway of neuronal activation in the cortex to a pattern that was within the level of resolution and another to patterns that were not. It was implied that a similar difference in impulse transmission to pattern and non-pattern stimuli may be recorded in humans. The present paper describes recordings of the short-latency visual evoked response to varying light flash checkerboard pattern stimuli of high intensity in visually normal and amblyopic children and adults. When stimulating the normal eye a visual evoked response potential with a peak latency between 35 to 40 ms showed a polarity change to patterned compared to non-patterned stimulation. The visual evoked response resolution limit could be correlated to a visual acuity of 0.5 and below. In amblyopic eyes the shift in polarity was recorded at the acuity limit level. The latency of the pattern depending potential was increased in patients with amblyopia compared to normal, but not directly related to amblyopic degree. It is concluded that the short latency, visual evoked response that mainly represents the retino-geniculo-cortical activation may be used to estimate visual resolution below 0.5 in acuity level.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis and antibacterial evaluation of calcinated Ag-doped nano-hydroxyapatite with dispersibility.

PubMed

Furuzono, Tsutomu; Motaharul, Mazumder; Kogai, Yasumichi; Azuma, Yoshinao; Sawa, Yoshiki

2015-05-01

Dispersible hydroxyapatite (HAp) nanoparticles are very useful for applying a monolayer to implantable medical devices using the nano-coating technique. To improve tolerance to infection on implanted medical devices, silver-doped HAp (Ag-HAp) nanoparticles with dispersiblity and crystallinity were synthesized, avoiding calcination-induced sintering, and evaluated for antibacterial activity. The Ca10-xAgx(PO4)6(OH)2 with x = 0 and 0.2 were prepared by wet chemical processing at 100°C. Before calcination at 700°C for 2 h, two kinds of anti-sintering agents, namely a Ca(NO3)2 (Ca salt) and a polyacrylic acid/Ca salt mixture (PAA-Ca), were used. Escherichia coli was used to evaluate the antibacterial activity of the nanopowder. When PAA-Ca was used as an anti-sintering agent in calcination to prepare the dispersible nanoparticles, strong metallic Ag peaks were observed at 38.1° and 44.3° (2θ) in the X-ray diffraction (XRD) profile. However, the Ag peak was barely observed when Ca salt was used alone as the anti-sintering agent. Thus, using Ca salt alone was more effective for preparation of dispersible Ag-HAp than PAA-Ca. The particle average size of Ag-HAp with 0.5 mol% of Ag content was found to be 325 ± 70 nm when the formation of large particleaggregations was prevented, as determined by dynamic light scattering instrument. The antibacterial activity of the Ag-HAp nanoparticles possessing 0.5 mol% against E. coli was greater than 90.0%. Dispersible and crystalline nano Ag-HAp can be obtained by using Ca salt alone as an anti-sintering agent. The nanoparticles showed antibacterial activity.

Progressive Reduction of its Expression in Rods Reveals Two Pools of Arrestin-1 in the Outer Segment with Different Roles in Photoresponse Recovery

PubMed Central

Cleghorn, Whitney M.; Tsakem, Elviche L.; Song, Xiufeng; Vishnivetskiy, Sergey A.; Seo, Jungwon; Chen, Jeannie; Gurevich, Eugenia V.; Gurevich, Vsevolod V.

2011-01-01

Light-induced rhodopsin signaling is turned off with sub-second kinetics by rhodopsin phosphorylation followed by arrestin-1 binding. To test the availability of the arrestin-1 pool in dark-adapted outer segment (OS) for rhodopsin shutoff, we measured photoresponse recovery rates of mice with arrestin-1 content in the OS of 2.5%, 5%, 60%, and 100% of wild type (WT) level by two-flash ERG with the first (desensitizing) flash at 160, 400, 1000, and 2500 photons/rod. The time of half recovery (thalf) in WT retinas increases with the intensity of the initial flash, becoming ∼2.5-fold longer upon activation of 2500 than after 160 rhodopsins/rod. Mice with 60% and even 5% of WT arrestin-1 level recovered at WT rates. In contrast, the mice with 2.5% of WT arrestin-1 had a dramatically slower recovery than the other three lines, with the thalf increasing ∼28 fold between 160 and 2500 rhodopsins/rod. Even after the dimmest flash, the rate of recovery of rods with 2.5% of normal arrestin-1 was two times slower than in other lines, indicating that arrestin-1 level in the OS between 100% and 5% of WT is sufficient for rapid recovery, whereas with lower arrestin-1 the rate of recovery dramatically decreases with increased light intensity. Thus, the OS has two distinct pools of arrestin-1: cytoplasmic and a separate pool comprising ∼2.5% that is not immediately available for rhodopsin quenching. The observed delay suggests that this pool is localized at the periphery, so that its diffusion across the OS rate-limits the recovery. The line with very low arrestin-1 expression is the first where rhodopsin inactivation was made rate-limiting by arrestin manipulation. PMID:21818392

Progressive reduction of its expression in rods reveals two pools of arrestin-1 in the outer segment with different roles in photoresponse recovery.

PubMed

Cleghorn, Whitney M; Tsakem, Elviche L; Song, Xiufeng; Vishnivetskiy, Sergey A; Seo, Jungwon; Chen, Jeannie; Gurevich, Eugenia V; Gurevich, Vsevolod V

2011-01-01

Light-induced rhodopsin signaling is turned off with sub-second kinetics by rhodopsin phosphorylation followed by arrestin-1 binding. To test the availability of the arrestin-1 pool in dark-adapted outer segment (OS) for rhodopsin shutoff, we measured photoresponse recovery rates of mice with arrestin-1 content in the OS of 2.5%, 5%, 60%, and 100% of wild type (WT) level by two-flash ERG with the first (desensitizing) flash at 160, 400, 1000, and 2500 photons/rod. The time of half recovery (t(half)) in WT retinas increases with the intensity of the initial flash, becoming ∼2.5-fold longer upon activation of 2500 than after 160 rhodopsins/rod. Mice with 60% and even 5% of WT arrestin-1 level recovered at WT rates. In contrast, the mice with 2.5% of WT arrestin-1 had a dramatically slower recovery than the other three lines, with the t(half) increasing ∼28 fold between 160 and 2500 rhodopsins/rod. Even after the dimmest flash, the rate of recovery of rods with 2.5% of normal arrestin-1 was two times slower than in other lines, indicating that arrestin-1 level in the OS between 100% and 5% of WT is sufficient for rapid recovery, whereas with lower arrestin-1 the rate of recovery dramatically decreases with increased light intensity. Thus, the OS has two distinct pools of arrestin-1: cytoplasmic and a separate pool comprising ∼2.5% that is not immediately available for rhodopsin quenching. The observed delay suggests that this pool is localized at the periphery, so that its diffusion across the OS rate-limits the recovery. The line with very low arrestin-1 expression is the first where rhodopsin inactivation was made rate-limiting by arrestin manipulation.

Noncontacting devices to indicate deflection and vibration of turbopump internal rotating parts

NASA Technical Reports Server (NTRS)

Hamilton, D. B.; Ensminger, D.; Grieser, D. R.; Plummer, A. M.; Saccocio, E. J.; Kissel, J. W.

1973-01-01

The research is reported which was conducted to develop devices for measuring vibrations and deflections of parts, such as impellers, shafts, turbine wheels, and inducers in operating turbopumps. Three devices were developed to the breadboard stage: ultrasonic Doppler transducer, flash X-rays, and light-pipe reflectance. It was found that the X-ray technique is applicable to the shaft assembly and the turbine seal of the J-2 pump, and the light-pipe-reflectance device appears to be ideal for cryogenic pump sections.

33 CFR 165.151 - Safety Zones; Fireworks Displays, Air Shows and Swim Events in the Captain of the Port Long...

Code of Federal Regulations, 2013 CFR

2013-07-01

..., flashing light or other means, the operator of the vessel shall proceed as directed. Failure to comply with... Blue Point, NY in approximate position 40°44′6.28″ N, 073°01′02.50″ W (NAD 83). 7.44National Golf Links... Light, Mystic, CT in approximate position 41°21′56.455″ N, 071°57′58.32″ W (NAD 83). 11.2Christmas Boat...

33 CFR 165.151 - Safety Zones; Fireworks Displays, Air Shows and Swim Events in the Captain of the Port Long...

Code of Federal Regulations, 2014 CFR

2014-07-01

..., flashing light or other means, the operator of the vessel shall proceed as directed. Failure to comply with... Blue Point, NY in approximate position 40°44′6.28″ N, 073°01′02.50″ W (NAD 83). 7.44National Golf Links... Light, Mystic, CT in approximate position 41°21′56.455″ N, 071°57′58.32″ W (NAD 83). 11.2Christmas Boat...

100-watt sonoluminescence generated by 2.5-atmosphere-pressure pulses

NASA Astrophysics Data System (ADS)

Kappus, Brian; Khalid, Shahzad; Putterman, Seth

2011-05-01

A Xenon gas bubble introduced into a vertically suspended steel cylinder is driven to sonoluminescence by impacting the apparatus against a solid steel base. This produces a 150-ns flash of broadband light that exceeds 100-W peak intensity and has a spectral temperature of 10 200 K. This bubble system, which yields light with a single shot, emits very powerful sonoluminescence. A jet is visible following bubble collapse, which demonstrates that spherical symmetry is not necessary to produce sonoluminescence.

100-Watt sonoluminescence generated by 2.5-atmosphere-pressure pulses.

PubMed

Kappus, Brian; Khalid, Shahzad; Putterman, Seth

2011-05-01

A Xenon gas bubble introduced into a vertically suspended steel cylinder is driven to sonoluminescence by impacting the apparatus against a solid steel base. This produces a 150-ns flash of broadband light that exceeds 100-W peak intensity and has a spectral temperature of 10,200 K. This bubble system, which yields light with a single shot, emits very powerful sonoluminescence. A jet is visible following bubble collapse, which demonstrates that spherical symmetry is not necessary to produce sonoluminescence. © 2011 American Physical Society

Light-Based Triggering and Reconstruction of Michel Electrons in LArIAT

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

Foreman, W.

2016-01-19

The LArIAT Experiment aims to calibrate the liquid argon time projection chamber (LArTPC) using a beam of charged particles at the Fermilab Test Beam Facility. It is equipped with a novel scintillation light readout system using PMTs and custom SiPM preamplifier boards to detect light from reflector foils coated with wavelength-shifting TPB. A trigger on delayed secondary flashes of light captures events containing stopping cosmic muons together with the Michel electrons coming from their subsequent decay. This dedicated Michel trigger supplies an abundant sample of low-energy electrons throughout the detector's active volume, providing opportunities to study the combined calorimetric capabilitiesmore » of the light system and the TPC. Preliminary results using scintillation light to study properties of the Michel electron sample are presented.« less

ASA-FTL: An adaptive separation aware flash translation layer for solid state drives

DOE PAGES

Xie, Wei; Chen, Yong; Roth, Philip C

2016-11-03

Here, the flash-memory based Solid State Drive (SSD) presents a promising storage solution for increasingly critical data-intensive applications due to its low latency (high throughput), high bandwidth, and low power consumption. Within an SSD, its Flash Translation Layer (FTL) is responsible for exposing the SSD’s flash memory storage to the computer system as a simple block device. The FTL design is one of the dominant factors determining an SSD’s lifespan and performance. To reduce the garbage collection overhead and deliver better performance, we propose a new, low-cost, adaptive separation-aware flash translation layer (ASA-FTL) that combines sampling, data clustering and selectivemore » caching of recency information to accurately identify and separate hot/cold data while incurring minimal overhead. We use sampling for light-weight identification of separation criteria, and our dedicated selective caching mechanism is designed to save the limited RAM resource in contemporary SSDs. Using simulations of ASA-FTL with both real-world and synthetic workloads, we have shown that our proposed approach reduces the garbage collection overhead by up to 28% and the overall response time by 15% compared to one of the most advanced existing FTLs. We find that the data clustering using a small sample size provides significant performance benefit while only incurring a very small computation and memory cost. In addition, our evaluation shows that ASA-FTL is able to adapt to the changes in the access pattern of workloads, which is a major advantage comparing to existing fixed data separation methods.« less

Disease Course of Patients with Unilateral Pigmentary Retinopathy

PubMed Central

Potsidis, Emorfily; Berson, Eliot L.

2011-01-01

Purpose. To evaluate the change in ocular function by eye in patients with unilateral pigmentary retinopathy. Methods. Longitudinal regression was used to estimate mean exponential rates of change in Goldmann visual field area (V4e white test light) and in full-field electroretinogram (ERG) amplitudes to 0.5- and 30-Hz white flashes in 15 patients with unilateral pigmentary retinopathy. Snellen visual acuity was assessed case by case. Results. Mean annual rates of change for the affected eyes were −4.9% for visual field area, −4.7% for ERG amplitude to 0.5-Hz flashes, and −4.6% for ERG amplitude to 30-Hz flashes. All three rates were faster than the corresponding age-related rates of change for the fellow normal eyes (P = 0.0006, P = 0.003, P = 0.03, respectively). An initial cone ERG implicit time to 30-Hz flashes in affected eyes ≥40 ms predicted a faster mean rate of decline of visual field area and of ERG amplitude to 0.5- and 30-Hz flashes (P < 0.0001 for all three measures). The visual acuity of affected eyes was more likely to decrease in patients presenting at >35 years of age than in patients presenting at a younger age (P = 0.0004). Conclusions. The affected eye in unilateral pigmentary retinopathy shows a progressive loss of peripheral retinal function that cannot be attributed to aging alone and that is faster in eyes with a more prolonged initial cone ERG implicit time. Patients presenting at >35 years of age are at greater risk for losing visual acuity. PMID:21989720

Disease course of patients with unilateral pigmentary retinopathy.

PubMed

Potsidis, Emorfily; Berson, Eliot L; Sandberg, Michael A

2011-11-29

To evaluate the change in ocular function by eye in patients with unilateral pigmentary retinopathy. Longitudinal regression was used to estimate mean exponential rates of change in Goldmann visual field area (V4e white test light) and in full-field electroretinogram (ERG) amplitudes to 0.5- and 30-Hz white flashes in 15 patients with unilateral pigmentary retinopathy. Snellen visual acuity was assessed case by case. Mean annual rates of change for the affected eyes were -4.9% for visual field area, -4.7% for ERG amplitude to 0.5-Hz flashes, and -4.6% for ERG amplitude to 30-Hz flashes. All three rates were faster than the corresponding age-related rates of change for the fellow normal eyes (P = 0.0006, P = 0.003, P = 0.03, respectively). An initial cone ERG implicit time to 30-Hz flashes in affected eyes ≥ 40 ms predicted a faster mean rate of decline of visual field area and of ERG amplitude to 0.5- and 30-Hz flashes (P < 0.0001 for all three measures). The visual acuity of affected eyes was more likely to decrease in patients presenting at >35 years of age than in patients presenting at a younger age (P = 0.0004). The affected eye in unilateral pigmentary retinopathy shows a progressive loss of peripheral retinal function that cannot be attributed to aging alone and that is faster in eyes with a more prolonged initial cone ERG implicit time. Patients presenting at >35 years of age are at greater risk for losing visual acuity.

What are the limits of energy focusing in sonoluminescence?

NASA Astrophysics Data System (ADS)

Putterman, Seth; Camara, C.; Kappus, B.; Su, C. K.; Kirilov, E.

2003-04-01

Sonoluminescence [SL] is amazing for the extraordinary degree by which ultrasonic energy can be focused by a cavitating bubble. Local energy dissipation exceeds Kirkhoff's law by 1E15 and the acoustic energy density concentrates by 12 orders of magnitude to create picosecond flashes of broadband ultraviolet light. At the minimum bubble radius, the acceleration exceeds 1E11 g and a megabar level shock wave is emitted into the surrounding fluid. For single bubbles driven at 30 KHz, SL is nature's smallest blackbody. This implies that the bubble's interior is such a dense plasma that the photon-matter mean free path is shorter than the wavelength of light, and suggests that SL originates in an unusual state of matter. Excitation of a vertical column of fluid [~10 Hz] so as to create a water hammer leads to the upscaling of SL and generation of flashes of light with 3E8 photons and peak powers approaching 1 W. At 1 MHz, the spectrum resembles bremsstrahlung from a transparent plasma with a temperature ~1 MK. At 10 MHz the collapsed size of the SL bubble approaches 10 nm, which raises the possibility that the SL parameter space may extend to the domain of quantum mechanics. [Research supported by DARPA and DOE.

The peculiar Type Ia supernova iPTF14atg: Chandrasekhar-mass explosion or violent merger?

NASA Astrophysics Data System (ADS)

Kromer, M.; Fremling, C.; Pakmor, R.; Taubenberger, S.; Amanullah, R.; Cenko, S. B.; Fransson, C.; Goobar, A.; Leloudas, G.; Taddia, F.; Röpke, F. K.; Seitenzahl, I. R.; Sim, S. A.; Sollerman, J.

2016-07-01

iPTF14atg, a subluminous peculiar Type Ia supernova (SN Ia) similar to SN 2002es, is the first SN Ia for which a strong UV flash was observed in the early-time light curves. This has been interpreted as evidence for a single-degenerate (SD) progenitor system, where such a signal is expected from interactions between the SN ejecta and the non-degenerate companion star. Here, we compare synthetic observables of multidimensional state-of-the-art explosion models for different progenitor scenarios to the light curves and spectra of iPTF14atg. From our models, we have difficulties explaining the spectral evolution of iPTF14atg within the SD progenitor channel. In contrast, we find that a violent merger of two carbon-oxygen white dwarfs with 0.9 and 0.76 M⊙, respectively, provides an excellent match to the spectral evolution of iPTF14atg from 10 d before to several weeks after maximum light. Our merger model does not naturally explain the initial UV flash of iPTF14atg. We discuss several possibilities like interactions of the SN ejecta with the circumstellar medium and surface radioactivity from an He-ignited merger that may be able to account for the early UV emission in violent merger models.

Evaluation of Infrasound and Strobe Lights for Eliciting Avoidance Behavior in Juvenile Salmon and Char

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

Mueller, Robert P.; Neitzel, Duane A.; Amidan, Brett G.

2001-12-01

Laboratory tests were conducted using juvenile chinook salmon Oncorhynchus tshawytscha, brook trout Salvelinus fontinalis, and rainbow trout O. mykiss to determine specific behavior responses to infrasound (< 20 Hz) and flashing strobe lights. The objective of these tests was to determine if juvenile salmonids could be deterred from entrainment at water diversion structures. Caged fish were acclimated in a static test tank and their behavior was recorded using low light cameras. Species-specific behavior was characterized by measuring movements of the fish within the cage and by observing startle and habituation responses. Wild chinook salmon (40-45 mm TL) and hatchery rearedmore » chinook salmon (45-50 mm TL) exhibited avoidance responses when initially exposed to a 10-Hz volume displacement source of infrasound. Rainbow and eastern brook trout (25-100 mm TL) did not respond with avoidance or other behaviors to infrasound. Evidence of habituation to the infrasound source was evident for chinook salmon during repeated exposures. Wild and hatchery chinook displayed a higher proportion of movement during the initial exposures to infrasound when the acclimation period in the test tank was 2-3 h as compared to a 12-15 h acclimation period. A flashing strobe light produced consistent movement in wild chinook salmon (60% of the tests), hatchery reared chinook salmon (50%), and rainbow trout (80%). No measurable responses were observed for brook trout. Results indicate that consistent, repeatable responses can be elicited from some fish using high-intensity strobe lights under a controlled laboratory testing. The species specific behaviors observed in these experiments might be used to predict how fish might react to low-frequency sound and strobe lights in a screening facility.« less

Thermal Wadis in Support of Lunar Exploration: Concept Development and Utilization

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

Matyas, Josef; Wegeng, Robert S.; Burgess, Jeremy M.

2009-10-12

Thermal wadis, engineered sources of heat, can be used to extend the life of lunar rovers by keeping them warm during the extreme cold of the lunar night. Thermal wadis can be manufactured by sintering or melting lunar regolith into a solid mass with more than two orders of magnitude higher thermal diffusivities compared to native regolith dust. Small simulant samples were sintered and melted in the electrical furnaces at different temperatures, different heating and cooling rates, various soaking times, under air, or in an argon atmosphere. The samples were analyzed with scanning electron microscopy and energy dispersive spectroscopy, X-raymore » diffraction, a laser-flash thermal diffusivity system, and the millimeter-wave system. The melting temperature of JSC-1AF simulant was ~50°C lower in an Ar atmosphere compared to an air atmosphere. The flow of Ar during sintering and melting resulted in a small mass loss of 0.04 to 0.1 wt% because of the volatization of alkali compounds. In contrast, the samples that were heat-treated under an air atmosphere gained from 0.012 to 0.31 wt% of the total weight. A significantly higher number of cavities were formed inside the samples melted under an argon atmosphere, possibly because of the evolution of oxygen bubbles from iron redox reactions. The calculated emissivity of JSCf-1AF simulant did not change much with temperature, varying between 0.8 and 0.95 at temperatures from 100 to 1200°C. The thermal diffusivities of raw regolith that was compressed under a pressure of 9 metric tons ranged from 0.0013 to 00011 in the 27 to 390°C temperature range. The thermal diffusivities of sintered and melted JSC-1AF simulant varied from 0.0028 to 0.0072 cm2/s with the maximum thermal diffusivities observed in the samples that were heated up 5°C/min from RT to 1150°C under Ar or air. These thermal diffusivities are high enough for the rovers to survive the extreme cold of the Moon at the rim of the Shackleton Crater and allow them to operate for months (or years) as opposed to weeks on the lunar surface. Future investigations will be focused on a system that can efficiently construct a thermal wadi from the lunar mare regolith. Solar heating, microwave heating, or electrical resistance melting are considered.« less

Enhanced Oxidation-Resistant Cu@Ni Core-Shell Nanoparticles for Printed Flexible Electrodes.

PubMed

Kim, Tae Gon; Park, Hye Jin; Woo, Kyoohee; Jeong, Sunho; Choi, Youngmin; Lee, Su Yeon

2018-01-10

In this work, the fabrication and application of highly conductive, robust, flexible, and oxidation-resistant Cu-Ni core-shell nanoparticle (NP)-based electrodes have been reported. Cu@Ni core-shell NPs with a tunable Ni shell thickness were synthesized by varying the Cu/Ni molar ratios in the precursor solution. Through continuous spray coating and flash photonic sintering without an inert atmosphere, large-area Cu@Ni NP-based conductors were fabricated on various polymer substrates. These NP-based electrodes demonstrate a low sheet resistance of 1.3 Ω sq -1 under an optical energy dose of 1.5 J cm -2 . In addition, they exhibit highly stable sheet resistances (ΔR/R 0 < 1) even after 30 days of aging at 85 °C and 85% relative humidity. Further, a flexible heater fabricated from the Cu@Ni film is demonstrated, which shows uniform heat distribution and stable temperature compared to those of a pure Cu film.

Oxygen evolution from single- and multiple-turnover light pulses: temporal kinetics of electron transport through PSII in sunflower leaves.

PubMed

Oja, Vello; Eichelmann, Hillar; Laisk, Agu

2011-12-01

Oxygen evolution per single-turnover flash (STF) or multiple-turnover pulse (MTP) was measured with a zirconium O(2) analyzer from sunflower leaves at 22 °C. STF were generated by Xe arc lamp, MTP by red LED light of up to 18000 μmol quanta m(-2) s(-1). Ambient O(2) concentration was 10-30 ppm, STF and MTP were superimposed on far-red background light in order to oxidize plastoquinone (PQ) and randomize S-states. Electron (e(-)) flow was calculated as 4 times O(2) evolution. Q (A) → Q (B) electron transport was investigated firing double STF with a delay of 0 to 2 ms between the two. Total O(2) evolution per two flashes equaled to that from a single flash when the delay was zero and doubled when the delay exceeded 2 ms. This trend was fitted with two exponentials with time constants of 0.25 and 0.95 ms, equal amplitudes. Illumination with MTP of increasing length resulted in increasing O(2) evolution per pulse, which was differentiated with an aim to find the time course of O(2) evolution with sub-millisecond resolution. At the highest pulse intensity of 2.9 photons ms(-1) per PSII, 3 e(-) initially accumulated inside PSII and the catalytic rate of PQ reduction was determined from the throughput rate of the fourth and fifth e(-). A light response curve for the reduction of completely oxidized PQ was a rectangular hyperbola with the initial slope of 1.2 PSII quanta per e(-) and V (m) of 0.6 e(-) ms(-1) per PSII. When PQ was gradually reduced during longer MTP, V (m) decreased proportionally with the fraction of oxidized PQ. It is suggested that the linear kinetics with respect to PQ are apparent, caused by strong product inhibition due to about equal binding constants of PQ and PQH(2) to the Q (B) site. The strong product inhibition is an appropriate mechanism for down-regulation of PSII electron transport in accordance with rate of PQH(2) oxidation by cytochrome b(6)f. © Springer Science+Business Media B.V. 2011

Small impacts on the Giant Planet Jupiter

NASA Astrophysics Data System (ADS)

Hueso, Ricardo; Delcroix, Marc; Sanchez-Lavega, Agustin M.; Rojas, Jose Felix; María Gómez-Forrellad, Josep; Juaristi-Campillo, Jon

2017-10-01

Amateur video observations of Jupiter have shown five events of 1-s long flashes, each one observed by 2-3 observers geographically separated. The first three of these events occurred on June 3 2010, August 20 2010 and September 10 2012. Analysis of the light-curves of each flash shows that they most probably were caused by the impact of objects of 5-20 m depending on their density (Hueso et al., 2010, 2013) with a released energy comparable to superbolides on Earth similar to the Chelyabinsk airburst. The last two flashes on Jupiter were detected on 17 March 2016 and 26 May 2017 after a long pause in impacts detections of more than 3 years. In all of these cases no impact debri at the impact location was found in later observations.We present detailed light-curves of the five flashes. Photometric calibration of the images allows to constrain the size of the impacting objects. We estimate the flash observable characteristics of a Jupiter impact event that could leave an observable debri field on Jupiter’s atmosphere over a few days triggering fast observations. We also present results from a systematic search of impacts on >65,000 video amateur observations with a software specifically designed towards impact detection and based on differential photometry of frames over videos of Jupiter. From the observations of impacts and a statistical analysis of amateur observations the flux of small objects (5-20 m size) impacting Jupiter is predicted to be small (from 1 every 70 days to 1 every 12 days). A larger telescope than those used by amateurs could detect smaller impacts happening much more frequently. In spite of the uncertainties, these numbers imply that a dense number of observers are required to efficiently discover Jupiter impacts. The first three events were detected with Jupiter oppositions on September and December in 2010 and 2012 respectively and the last two events were detected with Jupiter oppositions in March and April 2017. We predict that more impacts will be found in the upcoming years with Jupiter opposition displaced towards the Summer in the Northern hemisphere where most amateur astronomers observe.References:Hueso et al. ApJ, 721L (2010).Hueso et al. A&A, 560, A55 (2013).

Aspherical Supernovae and Oblique Shock Breakout

NASA Astrophysics Data System (ADS)

Afsariardchi, Niloufar; Matzner, Christopher D.

2017-02-01

In an aspherical supernova explosion, shock emergence is not simultaneous and non-radial flows develop near the stellar surface. Oblique shock breakouts tend to be easily developed in compact progenitors like stripped-envelop core collapse supernovae. According to Matzner et al. (2013), non-spherical explosions develop non-radial flows that alters the observable emission and radiation of a supernova explosion. These flows can limit ejecta speed, change the distribution of matter and heat of the ejecta, suppress the breakout flash, and most importantly engender collisions outside the star. We construct a global numerical FLASH hydrodynamic simulation in a two dimensional spherical coordinate, focusing on the non-relativistic, adiabatic limit in a polytropic envelope to see how these fundamental differences affect the early light curve of core-collapse SNe.

Photorefractor ocular screening system

NASA Technical Reports Server (NTRS)

Richardson, John R. (Inventor); Kerr, Joseph H. (Inventor)

1987-01-01

A method and apparatus for detecting human eye defects, particularly detection of refractive error is presented. Eye reflex is recorded on color film when the eyes are exposed to a flash of light. The photographs are compared with predetermined standards to detect eye defects. The base structure of the ocular screening system is a folding interconnect structure, comprising hinged sections. Attached to one end of the structure is a head positioning station which comprises vertical support, a head positioning bracket having one end attached to the top of the support, and two head positioning lamps to verify precise head positioning. At the opposite end of the interconnect structure is a camera station with camera, electronic flash unit, and blinking fixation lamp, for photographing the eyes of persons being evaluated.

The 2005 Project Progress Report for 1987-099-00 Dworshak Kokanee Population and Entrainment Assessment (contract # 16791) is attached to project 1987-099-00, contract # 26850. [POINTER

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

None

2008-12-18

During this contract, we continued testing underwater strobe lights to determine their effectiveness at repelling kokanee Oncorhynchus nerka away from Dworshak Dam. We tested one set of nine strobe lights flashing at a rate of 360 flashes/min in front of turbine 3 while operating at higher discharges than previously tested. The density and distribution of fish, (thought to be mostly kokanee), were monitored with a split-beam echo sounder. We then compared fish counts and densities during nights when the lights were flashing to counts and densities during adjacent nights without the lights on. On five nights between January 31 andmore » February 28, 2006, when no lights were present, fish counts near turbine 3 averaged eight fish and densities averaged 91 fish/ha. When strobe lights were turned on during five adjacent nights during the same period, mean counts dropped to four fish and densities dropped to 35 fish/ha. The decline in counts (49%) was not statistically significant (p = 0.182), but decline in densities (62%) was significant (p = 0.049). There appeared to be no tendency for fish to habituate to the lights during the night. Test results indicated that strobe lights were able to reduce fish densities by at least 50% in front of turbines operating at higher discharges, which would be sufficient to improve sportfish harvest. We also used split-beam hydroacoustics to monitor the kokanee population in Dworshak Reservoir during 2005. Estimated abundance of kokanee decreased from the 2004 population estimate. Based on hydroacoustic surveys, we estimated 3,011,626 kokanee (90% CI {+-} 15.2%) in Dworshak Reservoir, July 2005. This included 2,135,986 age-0 (90% CI {+-} 15.9%), 769,175 age-1 (90% CI {+-} 16.0%), and 107,465 age-2 (90% CI {+-} 15.2%). Poor survival of kokanee from age-1 to age-2 continued to keep age-2 densities below the management goal of 30-50 adults/ha. Entrainment sampling was conducted with fixed-site split-beam hydroacoustics a minimum of two days per month for a continuous 24 h period when dam operations permitted. The highest fish detection rates from entrainment assessments were again found during nighttime periods and lowest during the day. Fish detection rates were low during high discharges throughout the spring and summer and highest during low discharges in September and November. High discharge during drawdowns for anadromous fish flows in July and August again resulted in low detection rates and susceptibility to entrainment. Index counts of spawning kokanee in four tributary streams totaled 12,742 fish. This data fits the previously developed relationship between spawner counts and adult kokanee abundance in the reservoir.« less

78 FR 6033 - Safety Zone; MODU KULLUK; Sitkalidak Island to Kiliuda Bay, AK

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-29

... immediately following the MODU KULLUK grounding and provides a longer effective period in anticipation of... impact of regulations on small entities during rulemaking. The term ``small entities'' comprises small... being hailed by a U.S. Coast Guard vessel by siren, radio, flashing light or other means, the operator...

Hazards of Colour Coding in Visual Approach Slope Indicators,

DTIC Science & Technology

1981-12-01

the glideslope. The central spot (the ’ meatball ’) is displaced above or below the datum lights when the pilot views from above or below the...undershoot is increasing or decreasing, the step changes in intensity may also be evident as a form of flash coding. Colour coding of the ’ meatball " in

Interior, building 1205, view to southeast showing roof truss system, ...

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

Interior, building 1205, view to southeast showing roof truss system, sliding main doors, and roll up door at center to allow clearance for aircraft tail assembly, 90 mm lens plus electronic flash fill lighting. - Travis Air Force Base, Readiness Maintenance Hangar, W Street, Air Defense Command Readiness Area, Fairfield, Solano County, CA

Aircraft Alerting Systems Criteria Study. Volume II. Human Factors Guidelines for Aircraft Alerting Systems

DTIC Science & Technology

1977-05-01

Effect of Mixing Flashing and Steady Irrelevant Lights, Ergonomics, Vol. 6 (3), 1963, pp. 27-294. Creelman , C. D., Detection of Signals of Uncertain...Frequency, Acoustical Sok. America-J, Vol. 32 (7), July 1960, pp. 805-10. Creelman , C. D., Detection, Discrimination, and Loudness of Short Tones

Relationships between Sensory Stimulation and Stereotyped Behaviour in Severely Mentally Retarded and Autistic Children.

ERIC Educational Resources Information Center

Goodall, Elizabeth; Corbett, J.

1982-01-01

The reinforcing properties of four sensory stimuli (continuous and flashing light, vibration, and sound), which were under the subject's control, were examined and the effect on stereotyped behavior of 24 severely retarded and autistic children were observed. Findings were interpreted to support the self-stimulation theory of stereotypy despite…

A versatile approach to organic photovoltaics evaluation using white light pulse and microwave conductivity.

PubMed

Saeki, Akinori; Yoshikawa, Saya; Tsuji, Masashi; Koizumi, Yoshiko; Ide, Marina; Vijayakumar, Chakkooth; Seki, Shu

2012-11-21

State-of-the-art low band gap conjugated polymers have been investigated for application in organic photovoltaic cells (OPVs) to achieve efficient conversion of the wide spectrum of sunlight into electricity. A remarkable improvement in power conversion efficiency (PCE) has been achieved through the use of innovative materials and device structures. However, a reliable technique for the rapid screening of the materials and processes is a prerequisite toward faster development in this area. Here we report the realization of such a versatile evaluation technique for bulk heterojunction OPVs by the combination of time-resolved microwave conductivity (TRMC) and submicrosecond white light pulse from a Xe-flash lamp. Xe-flash TRMC allows examination of the OPV active layer without requiring fabrication of the actual device. The transient photoconductivity maxima, involving information on generation efficiency, mobility, and lifetime of charge carriers in four well-known low band gap polymers blended with phenyl-C(61)-butyric acid methyl ester (PCBM), were confirmed to universally correlate with the PCE divided by the open circuit voltage (PCE/V(oc)), offering a facile way to predict photovoltaic performance without device fabrication.

Aerogel Cherenkov detector for characterizing the intense flash x-ray source, Cygnus, spectrum

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

Kim, Y., E-mail: yhkim@lanl.gov; Herrmann, H. W.; McEvoy, A. M.

2016-11-15

An aerogel Cherenkov detector is proposed to measure the X-ray energy spectrum from the Cygnus—intense flash X-ray source operated at the Nevada National Security Site. An array of aerogels set at a variety of thresholds between 1 and 3 MeV will be adequate to map out the bremsstrahlung X-ray production of the Cygnus, where the maximum energy of the spectrum is normally around 2.5 MeV. In addition to the Cherenkov radiation from aerogels, one possible competing light-production mechanism is optical transition radiation (OTR), which may be significant in aerogels due to the large number of transitions from SiO{sub 2} clustersmore » to vacuum voids. To examine whether OTR is a problem, four aerogel samples were tested using a mono-energetic electron beam (varied in the range of 1–3 MeV) at NSTec Los Alamos Operations. It was demonstrated that aerogels can be used as a Cherenkov medium, where the rate of the light production is about two orders magnitude higher when the electron beam energy is above threshold.« less

Impact Flash Physics: Modeling and Comparisons With Experimental Results

NASA Astrophysics Data System (ADS)

Rainey, E.; Stickle, A. M.; Ernst, C. M.; Schultz, P. H.; Mehta, N. L.; Brown, R. C.; Swaminathan, P. K.; Michaelis, C. H.; Erlandson, R. E.

2015-12-01

Hypervelocity impacts frequently generate an observable "flash" of light with two components: a short-duration spike due to emissions from vaporized material, and a long-duration peak due to thermal emissions from expanding hot debris. The intensity and duration of these peaks depend on the impact velocity, angle, and the target and projectile mass and composition. Thus remote sensing measurements of planetary impact flashes have the potential to constrain the properties of impacting meteors and improve our understanding of impact flux and cratering processes. Interpreting impact flash measurements requires a thorough understanding of how flash characteristics correlate with impact conditions. Because planetary-scale impacts cannot be replicated in the laboratory, numerical simulations are needed to provide this insight for the solar system. Computational hydrocodes can produce detailed simulations of the impact process, but they lack the radiation physics required to model the optical flash. The Johns Hopkins University Applied Physics Laboratory (APL) developed a model to calculate the optical signature from the hot debris cloud produced by an impact. While the phenomenology of the optical signature is understood, the details required to accurately model it are complicated by uncertainties in material and optical properties and the simplifications required to numerically model radiation from large-scale impacts. Comparisons with laboratory impact experiments allow us to validate our approach and to draw insight regarding processes that occur at all scales in impact events, such as melt generation. We used Sandia National Lab's CTH shock physics hydrocode along with the optical signature model developed at APL to compare with a series of laboratory experiments conducted at the NASA Ames Vertical Gun Range. The experiments used Pyrex projectiles to impact pumice powder targets with velocities ranging from 1 to 6 km/s at angles of 30 and 90 degrees with respect to horizontal. High-speed radiometer measurements were made of the time-dependent impact flash at wavelengths of 350-1100 nm. We will present comparisons between these measurements and the output of APL's model. The results of this validation allow us to determine basic relationships between observed optical signatures and impact conditions.

Generation of White Light from Dysprosium-Doped Strontium Aluminate Phosphor by a Solid-State Reaction Method

NASA Astrophysics Data System (ADS)

Sahu, Ishwar Prasad; Bisen, D. P.; Brahme, N.; Tamrakar, Raunak Kumar

2016-04-01

A single-host lattice, white light-emitting SrAl2O4:Dy3+ phosphor was synthesized by a solid-state reaction method. The crystal structure of prepared SrAl2O4:Dy3+ phosphor was in a monoclinic phase with space group P21. The chemical composition of the sintered SrAl2O4:Dy3+ phosphor was confirmed by the energy dispersive x-ray spectroscopy technique. Under ultra-violet excitation, the characteristic emissions of Dy3+ are peaking at 475 nm, 573 nm and 660 nm, originating from the transitions of 4F9/2 → 6H15/2, 4F9/2 →&!nbsp; 6H13/2 and 4F9/2 → 6H11/2 in the 4f9 configuration of Dy3+ ions. Commission International de I'Eclairage color coordinates of SrAl2O4:Dy3+ are suitable for white light-emitting phosphor. In order to investigate the suitability of the samples as white color light sources for industrial uses, correlated color temperature (CCT) and color rendering index (CRI) values were calculated. Values of CCT and CRI were found well within the defined acceptable range. Mechanoluminescence (ML) intensity of SrAl2O4:Dy3+ phosphor increased linearly with increasing impact velocity of the moving piston. Thus, the present investigation indicates piezo-electricity was responsible for producing ML in sintered SrAl2O4:Dy3+ phosphor. Decay rates of the exponential decaying period of the ML curves do not change significantly with impact velocity. The photoluminescence and ML results suggest that the synthesized SrAl2O4:Dy3+ phosphor was useful for the white light-emitting diodes and stress sensor respectively.