"Light-box" accelerated growth of poinsettias: LED-only illumination

NASA Astrophysics Data System (ADS)

Weerasuriya, Charitha; Detez, Stewart; Hock Ng, Soon; Hughes, Andrew; Callaway, Michael; Harrison, Iain; Katkus, Tomas; Juodkazis, Saulius

2018-01-01

For the current commercialized agricultural industry which requires a reduced product lead time to customer and supply all year round, an artificial light emitting diodes (LEDs)-based illumination has high potential due to high efficiency of electrical-to-light conversion. The main advantage of the deployed Red Green Blue Amber LED lighting system is colour mixing capability, which means ability to generate all the colours in the spectrum by using three or four primary colours LEDs. The accelerated plant growth was carried out in a "light-box" which was made to generate an artificial day/night cycle by moving the colour mixing ratio along the colour temperature curve of the chromaticity diagram. The control group of plants form the same initial batch was grown on the same shelf in a greenhouse at the same conditions with addition of artificial illumination by incandescent lamps for few hours. Costs and efficiency projections of LED lamps for horticultural applications is discussed together with required capital investment. The total cost of the "light-box" including LED lamps and electronics was 850 AUD.

Investigation of pitch and angle in the gradual-triangle lenticular lens for point-blank LED fog lamp.

PubMed

Chen, Hsi-Chao; Yang, Chi-Hao

2014-05-10

The effects of different pitch and angle of gradual-triangle lenticular lens for the point-blank LED fog lamp were investigated under the standard of ECE R19. The novel LED fog lamp was assembled from a point-blank LED light source, a parabolic reflector, and a gradual-triangle lenticular lens. Light tracing analysis was used for the design of the gradual-triangle lenticular lens. The pitch, which varied from 1 to 6 mm, and the apex angle, which changed from 5 to 32 deg, were both investigated in regard to the gradual-triangle lenticular lens. The optimum pitch was 5 mm, and the efficiency of the lamp system and lenticular lens could reach 93% and 98.1% by simulation, respectively. The results of experiment had over 94%, which is similar to that of simulation by normalized cross correlation (NCC) for the light intensity.

Optical design of a light-emitting diode lamp for a maritime lighthouse.

PubMed

Jafrancesco, D; Mercatelli, L; Sansoni, P; Fontani, D; Sani, E; Coraggia, S; Meucci, M; Francini, F

2015-04-10

Traffic signaling is an emerging field for light-emitting diode (LED) applications. This sustainable power-saving illumination technology can be used in maritime signaling thanks to the recently updated norms, where the possibility to utilize LED sources is explicitly cited, and to the availability of high-power white LEDs that, combined with suitable lenses, permit us to obtain well-collimated beams. This paper describes the optical design of a LED-based lamp that can replace a traditional lamp in an authentic marine lighthouse. This source recombines multiple separated LEDs realizing a quasi-punctual localized source. Advantages can be lower energy consumption, higher efficiency, longer life, fewer faults, slower aging, and minor maintenance costs. The proposed LED source allows us to keep and to utilize the old Fresnel lenses of the lighthouse, which very often have historical value.

Investigation of thermal management technique in blue LED airport taxiway fixtures

NASA Astrophysics Data System (ADS)

Gu, Yimin; Baker, Alex; Narendran, Nadarajah

2007-09-01

On airport runways, blue light fixtures denote taxiways between the runway and the airport terminal. Blue optics transmit mostly short-wavelength radiation, which makes traditional incandescent lamps a poor choice of light source; the resulting fixture efficiency could be less than one percent. LEDs are replacing incandescent lamps in this application. But unlike incandescent sources, LEDs do not radiate enough heat to melt ice and snow from the fixture optics. To meet Federal Aviation Administration (FAA) regulations for weatherability, some LED-based fixtures incorporate electric heaters that, when switched on, nearly negate the energy-savings benefit of converting to LED sources. In this study, we explored methods for conduction and convection of LED junction heat to taxiway fixture optics for the purpose of minimizing snow and ice buildup. A more efficient LED-based system compared to incandescent that would require no additional heaters was demonstrated.

Comparative and quantitative analysis of white light-emitting diodes and other lamps used for home illumination

NASA Astrophysics Data System (ADS)

Rubinger, Rero Marques; da Silva, Edna Raimunda; Pinto, Daniel Zaroni; Rubinger, Carla Patrícia Lacerda; Oliveira, Adhimar Flávio; da Costa Bortoni, Edson

2015-01-01

We compared the photometric and radiometric quantities in the visible, ultraviolet, and infrared spectra of white light-emitting diodes (LEDs), incandescent light bulbs and a compact fluorescent lamp used for home illumination. The color-rendering index and efficiency-related quantities were also used as auxiliary tools in this comparison. LEDs have a better performance in all aspects except for the color-rendering index, which is better with an incandescent light bulb. Compact fluorescent lamps presented results that, to our knowledge, do not justify their substitution for the incandescent light bulb. The main contribution of this work is an approach based on fundamental quantities to evaluate LEDs and other light sources.

Evaluating UV-C LED disinfection performance and ...

EPA Pesticide Factsheets

This study evaluated ultraviolet (UV) light emitting diodes (LEDs) emitting at 260 nm, 280 nm, and the combination of 260|280 nm together for their efficacy at inactivating Escherichia. coli, MS2 coliphage, human adenovirus type 2 (HAdV2), and Bacillus pumilus spores; research included an evaluation of genomic damage. Inactivation by the LEDs was compared with the efficacy of conventional UV sources, the low-pressure (LP) and medium-pressure (MP) mercury vapor lamps. The work also calculated the electrical energy per order of reduction of the microorganisms by the five UV sources.For E. coli, all five UV sources yielded similar inactivation rates. For MS2 coliphage, the 260 nm LED was most effective. For HAdV2 and B. pumilus, the MP UV lamp was significantly more effective than the LP UV and UVC LED sources. When considering electrical energy per order of reduction, the LP UV lamp was the most efficient for E. coli and MS2, and the MPUV and LPUV were equally efficient for HAdV2 and B. pumilus spores. Among the UVC LEDs, the 280 nm LED unit required the least energy per log reduction of E. coli and HAdV2. The 280 nm and 260|280 nm LED units were equally efficient per log reduction of B. pumilus spores, and the 260 nm LED unit required the lowest energy per order of reduction of MS2 coliphage. The combination of the 260 nm and 280 nm UV LED wavelengths was also evaluated for potential synergistic effects. No dual-wavelength synergy was detected for inactivation of

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.

Investigation of structure in the modular light pipe component for LED automotive lamp

NASA Astrophysics Data System (ADS)

Chen, Hsi-Chao; Zhou, Yang; Huang, Chien-Sheng; Jhong, Wan-Ling; Cheng, Bo-Wei; Jhang, Jhe-Ming

2014-09-01

Light-Emitting Diodes (LEDs) have the advantages of small length, long lifetime, fast response time (μs), low voltage, good mechanical properties and environmental protection. Furthermore, LEDs could replace the halogen lamps to avoid the mercury pollution and economize the use of energy. Therefore, the LEDs could instead of the traditional lamp in the future and became an important light source. The proposal of this study was to investigate the effects of the structure and length of the reflector component for a LED automotive lamp. The novel LED automotive lamp was assembled by several different modularization columnar. The optimized design of the different structure and the length to the reflector was simulated by software TracePro. The design result must met the vehicle regulation of United Nations Economic Commission for Europe (UNECE) such as ECE-R19 etc. The structure of the light pipe could be designed by two steps structure. Then constitute the proper structure and choose different power LED to meet the luminous intensity of the vehicle regulation. The simulation result shows the proper structure and length has the best total luminous flux and a high luminous efficiency for the system. Also, the stray light could meet the vehicle regulation of ECE R19. Finally, the experimental result of the selected structure and length of the light pipe could match the simulation result above 80%.

Integration of non-Lambertian LED and reflective optical element as efficient street lamp.

PubMed

Pan, Jui-Wen; Tu, Sheng-Han; Sun, Wen-Shing; Wang, Chih-Ming; Chang, Jenq-Yang

2010-06-21

A cost effective, high throughput, and high yield method for the increase of street lamp potency was proposed in this paper. We integrated the imprinting technology and the reflective optical element to obtain a street lamp with high illumination efficiency and without glare effect. The imprinting technique can increase the light extraction efficiency and modulate the intensity distribution in the chip level. The non-Lambertian light source was achieved by using imprinting technique. The compact reflective optical element was added to efficiently suppress the emitting light intensity with small emitting angle for the uniform of illumination intensity and excluded the light with high emitting angle for the prevention of glare. Compared to the conventional street lamp, the novel design has 40% enhancement in illumination intensity, the uniform illumination and the glare effect elimination.

Microbial UV fluence-response assessment using a novel UV-LED collimated beam system.

PubMed

Bowker, Colleen; Sain, Amanda; Shatalov, Max; Ducoste, Joel

2011-02-01

A research study has been performed to determine the ultraviolet (UV) fluence-response of several target non-pathogenic microorganisms to UV light emitting diodes (UV-LEDs) by performing collimated beam tests. UV-LEDs do not contain toxic mercury, offer design flexibility due to their small size, and have a longer operational life than mercury lamps. Comsol Multiphysics was utilized to create an optimal UV-LED collimated beam design based on number and spacing of UV-LEDs and distance of the sample from the light source while minimizing the overall cost. The optimized UV-LED collimated beam apparatus and a low-pressure mercury lamp collimated beam apparatus were used to determine the UV fluence-response of three surrogate microorganisms (Escherichia coli, MS-2, T7) to 255 nm UV-LEDs, 275 nm UV-LEDs, and 254 nm low-pressure mercury lamps. Irradiation by low-pressure mercury lamps produced greater E. coli and MS-2 inactivation than 255 nm and 275 nm UV-LEDs and similar T7 inactivation to irradiation by 275 nm UV-LEDs. The 275 nm UV-LEDs produced more efficient T7 and E. coli inactivation than 255 nm UV-LEDs while both 255 nm and 275 nm UV-LEDs produced comparable microbial inactivation for MS-2. Differences may have been caused by a departure from the time-dose reciprocity law due to microbial repair mechanisms. Copyright © 2010 Elsevier Ltd. All rights reserved.

Laser Based Phosphor Converted Solid State White Light Emitters

NASA Astrophysics Data System (ADS)

Cantore, Michael

Artificial lighting and as a consequence the ability to be productive when the sun does not shine may be a profound achievement in society that is largely taken for granted. As concerns arise due to our dependence on energy sources with finite lifespan or environmentally negative effects, efforts to reduce energy consumption and create clean renewable alternatives has become highly valued. In the scope of artificial lighting, the use of incandescent lamps has shifted to more efficient light sources. Fluorescent lighting made the first big gains in efficiency over incandescent lamps with peak efficiency for mature designs reaching luminous efficacy of approximately 90 lm/W; more than three times as efficient as an incandescent lamp. Lamps based on light emitting diodes (LEDs) which can produce light at even greater efficiency, color quality and without the potential for hazardous chemical release from lamp failure. There is a significant challenge with LED based light sources. Their peak efficiency occurs at low current densities and then droops as the current density increases. Laser diodes (LDs) do not suffer from decreasing efficiency due to increased current. An alternative solid state light source using LDs has potential to make further gains in efficiency as well as allow novel illuminant designs which may be impractical or even impossible even with LED or other conventional sources. While similar to LEDS, the use of LDs does present new challenges largely due to the increased optical power density which must be accommodated in optics and phosphor materials. Single crystal YAG:Ce has been shown to be capable of enduring this more extreme operating environment while retaining the optical and fluorescing qualities desired for use as a wavelength converter in phosphor converted LD based white emitting systems. The incorporation of this single crystal phosphor in a system with a commercial laser diode with peak wall plug efficiency of 31% resulted in emission of white light with a luminous efficacy of 86.7 lm/W at a current of 1.4A. A total luminous flux of 1100 lm with luminous efficacy of 76 lm/W at 3.0 A current was achieved. Simulations have been conducted which show that as the InGaN LD technology matures towards the efficiencies of about 75%, which has been observed in the GaAs material system, luminous efficacy of similar blue LD with single crystal YAG:Ce systems will exceed 200 lm/W.

The initiating radical yields and the efficiency of polymerization for various dental photoinitiators excited by different light curing units.

PubMed

Neumann, Miguel G; Schmitt, Carla C; Ferreira, Giovana C; Corrêa, Ivo C

2006-06-01

To evaluate the efficiency of the photopolymerization of dental resins it is necessary to know to what extent the light emitted by the light curing units is absorbed by the photoinitiators. On the other hand, the efficiency of the absorbed photons to produce species that launch the polymerization process is also of paramount importance. Therefore, the previously determined PAE (photon absorption efficiency) is used in conjunction with the polymerization quantum yields for the photoinitiators, in order to be able to compare the total process on an equivalent basis. This parameter can be used to identify the best performance for the photochemical process with specific photoinitiators. The efficiency of LED (Ultrablue IS) and QTH (Optilux 401) lamps were tested comparing their performances with the photoinitiators camphorquinone (CQ); phenylpropanedione (PPD); monoacylphosphine oxide (Lucirin TPO); and bisacylphosphine oxide (Irgacure 819). The extent of photopolymerization per absorbed photon was determined from the polymerization quantum yields obtained by using the photoinitiators to polymerize methyl methacrylate, and afterwards combined with the previously determined PAEs. Although CQ presents a rather low polymerization quantum yield, its photopolymerization efficiency is practically the highest when irradiated with the Ultrablue LED. On the other hand, Lucirin is much more efficient than the other photoinitiators when irradiated with a QTH lamp, due to its high quantum yield and the overlap between its absorption spectrum and the output of the visible lamp light. Difference in photopolymerization efficiencies arise when combinations of photoinitiators are used, and when LED sources are used in preference to QTH. Mechanistic understanding is essential to optimal initiator formulation.

Color Degradation of Textiles with Natural Dyes and of Blue Scale Standards Exposed to White LED Lamps:Evaluation of White LED Lamps for Effectiveness as Museum Lighting

NASA Astrophysics Data System (ADS)

Ishii, Mie; Moriyama, Takayoshi; Toda, Masahiro; Kohmoto, Kohtaro; Saito, Masako

White light-emitting diodes (LED) are well suited for museum lighting because they emit neither UV nor IR radiation, which damage artifacts. The color degradation of natural dyes and blue scale standards (JIS L 0841) by white LED lamps are examined, and the performance of white LED lamps for museum lighting is evaluated. Blue scale standard grades 1-6 and silk fabrics dyed with 22 types of natural dyes classified as mid to highly responsive in a CIE technical report (CIE157:2004) were exposed to five types of white LED lamps using different luminescence methods and color temperatures. Color changes were measured at each 15000 lx·hr (500 lx at fabric surface × 300 hr) interval ten times. The accumulated exposure totaled 150000 lx·hr. The data on conventional white LED lamps and previously reported white fluorescent (W) and museum fluorescent (NU) lamps was evaluated. All the white LED lamps showed lower fading rates compared with a W lamp on a blue scale grade 1. The fading rate of natural dyes in total was the same between an NU lamp (3000 K) and a white LED lamp (2869 K). However, yellow natural dyes showed higher fading rates with the white LED lamp. This tendency is due to the high power characteristic of the LED lamp around 400-500 nm, which possibly contributes to the photo-fading action on the dyes. The most faded yellow dyes were Ukon (Curcuma longa L.) and Kihada (Phellodendron amurense Rupr.), and these are frequently used in historic artifacts such as kimono, wood-block prints, and scrolls. From a conservation point of view, we need to continue research on white LED lamps for use in museum lighting.

Evaluation of the Potential Optical Radiation Hazards with Led Lamps Intended for Home Use.

PubMed

James, Robert H; Landry, Robert J; Walker, Bennett N; Ilev, Ilko K

2017-01-01

The authors evaluated the potential for ocular damage from optical radiation emitted by Light Emitting Diode (LED) based lamps used for general illumination. Ten LED lamps were randomly selected off the shelf from a local home improvement store. The LEDs were behind diffusers in half of these lamps, while in the other half, the LEDs were clearly visible. In addition, a battery powered LED lantern having a LED source behind a diffuser was measured. The optical radiation emissions from two common incandescent lamps were also measured to compare the relative hazards of LED and incandescent lamps. All lamp samples were evaluated in accordance with procedures specified in the American National Standards Institute/Illuminating Engineering Society of North America (ANSI/IESNA) Standard RP-27.3. For comparison purposes, the lantern and 100 W incandescent lamps were also evaluated according to ANSI RP-27.1. These measurements indicate that no lamp evaluated poses any photobiological hazard, and therefore, all lamps fall in the RP-27.3 category of Exempt Group. However, when evaluated in accordance with RP-27.1, the 100 W incandescent lamp would be classified in Risk Group 1 (low risk), while the LED lantern would be classified in Risk Group 2 (moderate risk).

Light-Emitting Diode (LED) Traps Improve the Light-Trapping of Anopheline Mosquitoes.

PubMed

Costa-Neta, B M; da Silva, A A; Brito, J M; Moraes, J L P; Rebêlo, J M M; Silva, F S

2017-11-07

Numerous advantages over the standard incandescent lamp favor the use of light-emitting diodes (LEDs) as an alternative and inexpensive light source for sampling medically important insects in surveillance studies. Previously published studies examined the response of mosquitoes to different wavelengths, but data on anopheline mosquito LED attraction are limited. Center for Disease Control and Prevention-type light traps were modified by replacing the standard incandescent lamp with 5-mm LEDs, one emitting at 520 nm (green) and the other at 470 nm (blue). To test the influence of moon luminosity on LED catches, the experiments were conducted during the four lunar phases during each month of the study period. A total of 1,845 specimens representing eight anopheline species were collected. Anopheles (Nyssorhynchus) evansae (35.2%) was the most frequently collected, followed by An. (Nys.) triannulatus (21.9%), An. (Nys.) goeldii (12.9%), and An. (Nys.) argyritarsis (11.5%). The green LED was the most attractive light source, accounting for 43.3% of the individuals collected, followed by the blue (31.8%) and control (24.9%) lights. The LED traps were significantly more attractive than the control, independent of the lunar phase. Light trapping of anopheline mosquitoes was more efficient when the standard incandescent lamp was replaced with LEDs, regardless of the moon phase. The efficiency of LEDs improves light trapping results, and it is suggested that the use of LEDs as an attractant for anopheline mosquitoes should be taken into consideration when sampling anopheline mosquitoes. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Light Converting Inorganic Phosphors for White Light-Emitting Diodes

PubMed Central

Chen, Lei; Lin, Chun-Che; Yeh, Chiao-Wen; Liu, Ru-Shi

2010-01-01

White light-emitting diodes (WLEDs) have matched the emission efficiency of florescent lights and will rapidly spread as light source for homes and offices in the next 5 to 10 years. WLEDs provide a light element having a semiconductor light emitting layer (blue or near-ultraviolet (nUV) LEDs) and photoluminescence phosphors. These solid-state LED lamps, rather than organic light emitting diode (OLED) or polymer light-emitting diode (PLED), have a number of advantages over conventional incandescent bulbs and halogen lamps, such as high efficiency to convert electrical energy into light, reliability and long operating lifetime. To meet with the further requirement of high color rendering index, warm light with low color temperature, high thermal stability and higher energy efficiency for WLEDs, new phosphors that can absorb excitation energy from blue or nUV LEDs and generate visible emissions efficiently are desired. The criteria of choosing the best phosphors, for blue (450−480 nm) and nUV (380−400 nm) LEDs, strongly depends on the absorption and emission of the phosphors. Moreover, the balance of light between the emission from blue-nUV LEDs and the emissions from phosphors (such as yellow from Y3Al5O12:Ce3+) is important to obtain white light with proper color rendering index and color temperature. Here, we will review the status of phosphors for LEDs and prospect the future development.

The evolving price of household LED lamps: Recent trends and historical comparisons for the US market

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

Gerke, Brian F.; Ngo, Allison T.; Alstone, Andrea L.

2014-10-14

In recent years, household LED light bulbs (LED A lamps) have undergone a dramatic price decline. Since late 2011, we have been collecting data, on a weekly basis, for retail offerings of LED A lamps on the Internet. The resulting data set allows us to track the recent price decline in detail. LED A lamp prices declined roughly exponentially with time in 2011-2014, with decline rates of 28percent to 44percent per year depending on lumen output, and with higher-lumen lamps exhibiting more rapid price declines. By combining the Internet price data with publicly available lamp shipments indices for the USmore » market, it is also possible to correlate LED A lamp prices against cumulative production, yielding an experience curve for LED A lamps. In 2012-2013, LED A lamp prices declined by 20-25percent for each doubling in cumulative shipments. Similar analysis of historical data for other lighting technologies reveals that LED prices have fallen significantly more rapidly with cumulative production than did their technological predecessors, which exhibited a historical decline of 14-15percent per doubling of production.« less

LED luminaire longevity strategy models comparison

NASA Astrophysics Data System (ADS)

Lemieux, Hugo; Thibault, Simon; Martel, Alain A.

2010-08-01

As energy efficiency becomes more and more important, light-emitting diodes (LEDs) are a promising alternative to traditional lighting. Indeed, the energy efficiency of LEDs is still improving as their luminosity is modulated by current. Moreover, for applications such as exterior lamp posts, their small size, directionality, colors and high frequency response allow to combine them and provide design possibilities which are impossible with any other light source. However, as any lamp, LEDs have a lumen depreciation which is a function of both current and temperature. Thus, to take advantage of the full characteristics of LEDs, LED luminaire longevity strategies must be carefully studied and planned, especially since the IES and CIE guidelines state clearly that the luminaire must maintain the rated recommended light level until the end of the system's operating life. The recommended approach for LED luminaire specification is therefore to use the end-of-life light level when evaluating the luminaire. Different power supply strategies have been simulated to determine which one maximizes energy saving and lifetime. With these results, it appears that active control can save at least 25% in energy, but the best strategy cannot be determined because of uncertainties in luminosity degradation models.

CALiPER Retail Lamps Study 3

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

Royer, Michael P.; Beeson, Tracy A.

2014-02-01

The CALiPER program first began investigating LED lamps sold at retail stores in 2010, purchasing 33 products from eight retailers and covering six product categories. The findings revealed a fragmented marketplace, with large disparities in performance of different products, accuracy of manufacturer claims, and offerings from different retail outlets. Although there were some good products, looking back many would not be considered viable competitors to other available options, with too little lumen output, not high enough efficacy, or poor color quality. CALiPER took another look in late 2011purchasing 38 products of five different types from nine retailers and the improvementmore » was marked. Performance was up; retailer claims were more accurate; and the price per lumen and price per unit efficacy were down, although the price per product had not changed much. Nonetheless, there was still plenty of room for improvement, with the performance of LED lamps not yet reaching that of well-established classes of conventional lamps (e.g., 75 W incandescent A19 lamps). Since the second retail lamp study was published in early 2012, there has been substantial progress in all aspects of LED lamps available from retailers. To document this progress, CALiPER again purchased a sample of lamps from retail stores 46 products in total, focusing on A19, PAR30, and MR16 lamps but instead of a random sample, sought to select products to answer specific hypotheses about performance. These hypotheses focused on expanding ranges of LED equivalency, the accuracy of lifetime claims, efficacy and price trends, as well as changes to product designs. Among other results, key findings include: There are now very good LED options to compete with 60 W, 75 W, and 100 W incandescent A19 lamps, and 75 W halogen PAR30 lamps. MR16 lamps have shown less progress, but there are now acceptable alternatives to 35 W, 12 V halogen MR16 lamps and 50 W, 120 V halogen MR16 lamps for some applications. Other uses, such as in enclosed luminaires, may require more development. At the same price point, lamps purchased in 2013 tended to have higher output and slightly higher efficacy than in 2011 or 2010. Over 30% of the products purchased in 2013 exceeded the maximum efficacy measured in 2011 (71 lm/W), with the most efficacious product measured at 105 lm/W. There appears to be increasing consistency in color quality, with a vast majority of products having a CCT of 2700 K or 3000 K and a CRI between 80 and 85. There were also fewer poor performing products tested and more high-performing products available in 2013 than in previous years. The accuracy of equivalency and performance claims was better than in 2011, but remains a concern, with 43% of tested products failing to completely meet their equivalency claim and 20% of products failing to match the manufacturer’s performance data. Although progress has been substantial, on average LED lamps remain more expensive than other energy efficiency lighting technologies -- although some aspects can be superior. Although not universal to all product lines or all product types, the issue of insufficient lumen output from LED lamps is waning. Thus, manufacturers can focus on other issues, such as reducing cost, improving electrical/dimmer compatibility, eliminating flicker, or improving color quality. While these issues are not inherent to all products, they remain a concern for the broader market.« less

LIGHTING FOR READING: DESIGNING AN LED LUMINAIRE FOR HOMES AND OFFICES

EPA Science Inventory

Energy waste from traditional incandescent light bulbs was reduced by fluorescent lamps, but they pose a threat to the environment due to the mercury in each tube and disposal issues. Light emitting diodes (LEDs) provide superior energy efficiency, longer life, toxin-free comp...

Investigation of Passive Filter for LED Lamp

NASA Astrophysics Data System (ADS)

Sarwono, Edi; Facta, Mochammad; Handoko, Susatyo

2017-04-01

Light Emitting Diode lamp or LED lamp is one of the energy saving lamps nowadays widely used by consumers. However, LED lamp has contained harmonics caused by the rectifier circuit inside the lamp. Harmonics cause a quality problem in power system. As the harmonics present in current or voltage, the waveforms are distorted. Harmonics can lead to overheating in magnetic core of electrical equipments. In this paper, several tests are carried out to investigate the harmonic content of voltage and currents, and also the level of light intensity of the two brands of LED lamps. Measurements in this study are conducted by using HIOKI Power Quality Analyzer 3197. The test results show that the total harmonic distortion or THD of voltage on various brands of LED lamps did not exceed 5% as in compliance to the limit of IEEE standard 519-1992. The largest harmonic voltage is 2.9%, while maximum harmonic current for tested brands of LED lamp is 170.6%. The use of low pass filter in the form of LC filter was proposed. Based on experimental results, the application of LC filter at input side of LED lamp has successfully reduced THD current in the range of 85%-88%.

Performance of a novel LED lamp arrangement to reduce SNR fluctuation for multi-user visible light communication systems.

PubMed

Wang, Zixiong; Yu, Changyuan; Zhong, Wen-De; Chen, Jian; Chen, Wei

2012-02-13

This paper investigates the performance of our recently proposed LED lamp arrangement to reduce the SNR fluctuation from different locations in the room for multi-user visible light communications. The LED lamp arrangement consists of 4 LED lamps positioned in the corners and 12 LED lamps spread evenly on a circle. Our studies show that the SNR fluctuation under such a LED lamp arrangement is reduced from 14.5 dB to 0.9 dB, which guarantees that users can obtain almost identical communication quality, regardless of their locations. After time domain zero-forcing (ZF) equalization, the BER performances and channel capacities of 100-Mbit/s and 200-Mbit/s bipolar on-off-keying (OOK) signal with most significant inter-symbol interference (ISI) are very close to that of the channel without any ISI caused by this LED lamp arrangement.

Fluorescent Lamp Replacement Study

DTIC Science & Technology

2017-07-01

friendly products, advances in efficiency, and lower production costs for lamps. The conversion of fluorescent bulbs to LED technology has many benefits ...of 4727 W. An economic analysis was calculated to compare the various lighting technologies that were implemented at ATC and the cost benefits ...the various lighting technologies that were implemented at ATC and the cost benefits of each, a lifecycle comparison was made between the fluorescent

LED lamp power management system and method

DOEpatents

Gaines, James; Clauberg, Bernd; Van Erp, Josephus A. M.

2013-03-19

An LED lamp power management system and method including an LED lamp having an LED controller 58; a plurality of LED channels 60 operably connected to the LED controller 58, each of the plurality of LED channels 60 having a channel switch 62 in series with at least one shunted LED circuit 83, the shunted LED circuit 83 having a shunt switch 68 in parallel with an LED source 80. The LED controller 58 reduces power loss in one of the channel switch 62 and the shunt switch 68 when LED lamp electronics power loss (P.sub.loss) exceeds an LED lamp electronics power loss limit (P.sub.lim); and each of the channel switches 62 receives a channel switch control signal 63 from the LED controller 58 and each of the shunt switches 68 receives a shunt switch control signal 69 from the LED controller 58.

Biomass and pigments production in photosynthetic bacteria wastewater treatment: effects of light sources.

PubMed

Zhou, Qin; Zhang, Panyue; Zhang, Guangming

2015-03-01

This study is aimed at enhancing biomass and pigments production together with pollution removal in photosynthetic bacteria (PSB) wastewater treatment via different light sources. Red, yellow, blue, white LED and incandescent lamp were used. Results showed different light sources had great effects on the PSB. PSB had the highest biomass production, COD removal and biomass yield with red LED. The corresponding biomass, COD removal and biomass yield reached 2580 mg/L, 88.6% and 0.49 mg-biomass/mg-COD-removal, respectively. The hydraulic retention time of wastewater treatment could be shortened to 72 h with red LED. Mechanism analysis showed higher ATP was produced with red LED than others. Light sources could significantly affect the pigments production. The pigments productions were greatly higher with LED than incandescent lamp. Yellow LED had the highest pigments production while red LED produced the highest carotenoid/bacteriochlorophyll ratio. Considering both efficiency and energy cost, red LED was the optimal light source. Copyright © 2014 Elsevier Ltd. All rights reserved.

Stakeholder Values and Perspectives when Implementing Led Lights on Navy Ships

DTIC Science & Technology

2014-06-01

Additionally, the M1 IntelliTube is a retrofit lamp , 32 which works with line power or any of the legacy ballasts.” ( LED /IntelliTube NAVSEA: LED ...only factor taken into consideration, then break-even point for LED lighting, Navy- wide, is approximately one hour to change the lamp . Of note...Energy Focus. (2013, July 3). Energy Focus: Specifications: IntelliTube LED replacement lamp , 24”, T12 LED lamp . Retrieved from http

LED lighting increases the ecological impact of light pollution irrespective of color temperature.

PubMed

Pawson, S M; Bader, M K-F

Recognition of the extent and magnitude of night-time light pollution impacts on natural ecosystems is increasing, with pervasive effects observed in both nocturnal and diurnal species. Municipal and industrial lighting is on the cusp of a step change where energy-efficient lighting technology is driving a shift from “yellow” high-pressure sodium vapor lamps (HPS) to new “white” light-emitting diodes (LEDs). We hypothesized that white LEDs would be more attractive and thus have greater ecological impacts than HPS due to the peak UV-green-blue visual sensitivity of nocturnal invertebrates. Our results support this hypothesis; on average LED light traps captured 48% more insects than were captured with light traps fitted with HPS lamps, and this effect was dependent on air temperature (significant light × air temperature interaction). We found no evidence that manipulating the color temperature of white LEDs would minimize the ecological impacts of the adoption of white LED lights. As such, large-scale adoption of energy-efficient white LED lighting for municipal and industrial use may exacerbate ecological impacts and potentially amplify phytosanitary pest infestations. Our findings highlight the urgent need for collaborative research between ecologists and electrical engineers to ensure that future developments in LED technology minimize their potential ecological effects.

240 nm UV LEDs for LISA test mass charge control

NASA Astrophysics Data System (ADS)

Olatunde, Taiwo; Shelley, Ryan; Chilton, Andrew; Serra, Paul; Ciani, Giacomo; Mueller, Guido; Conklin, John

2015-05-01

Test Masses inside the LISA Gravitational Reference Sensor must maintain almost pure geodesic motion for gravitational waves to be successfully detected. LISA requires residual test mass accelerations below 3 fm/s2/√Hz at all frequencies between 0.1 and 3 mHz. One of the well-known noise sources is associated with the charges on the test masses which couple to stray electrical potentials and external electromagnetic fields. LISA Pathfinder will use Hg-discharge lamps emitting mostly around 254 nm to discharge the test masses via photoemission in its 2015/16 flight. A future LISA mission launched around 2030 will likely replace the lamps with newer UV-LEDs. Presented here is a preliminary study of the effectiveness of charge control using latest generation UV-LEDs which produce light at 240 nm with energy above the work function of pure Au. Their lower mass, better power efficiency and small size make them an ideal replacement for Hg lamps.

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

Paget, Maria L.; McCullough, Jeffrey J.; Steward, Heidi E.

Solid-state lighting products for general lighting applications are now gaining a market presence, and more and more people are asking, “Which of these are ‘good’ products? Do they perform as claimed? How do they compare? Light Emitting Diodes (LEDs) differ from other light sources enough to require new procedures for measuring their performance and comparing to other lighting options, so both manufacturers and buyers are facing a learning curve. The energy-efficiency community has traditionally compared light sources based on system efficacy: rated lamp lumens divided by power into the system. This doesn’t work for LEDs because there are no standardmore » LED “lamp” packages and no lamp ratings, and because LED performance depends heavily on thermal, electrical, and optical design of complete lighting unit or ‘luminaire’. Luminaire efficacy is the preferred metric for LEDs because it measures the net light output from the luminaire divided by power into the system.« less

The design of optical module of LED street lamp with non-axial symmetrical reflector

NASA Astrophysics Data System (ADS)

Lu, Ming-Jun; Chen, Chi-An; Chen, Yi-Yung; Whang, Allen Jong-Woei

2010-05-01

In recently, many research focus on the LED applications for environmental protection so a number of LED street lamps are presented. Although LED has many advantages for environmental protection, its special optical characteristics, such as intensity distribution, always limit the advantages in many applications. Therefore, we always need to do the secondary optical design for LED street lamp to replace the traditional optical designs that are designed for high-pressure sodium lamps and mercury lamps. According to the situation, we design an optical module of LED street lamp with LEDs and secondary optical design. First, the LEDs are placed on freeform reflector for the specific illuminated conditions. We design the optical module of street lamp with the two conditions that include the uniformity and the ratio of length to width in the illuminated area and without any light pollution. According to the simulation with the designed optical module, the uniformity in the illuminated area is about 0.6 that is better than the general condition, 0.3, and the ratio of length to width in the illuminated area is 3:1 in which the length is 30 meters and the width is 10 meters. Therefore, the design could let LED street lamp fits the two conditions, uniformity and ratio in the illuminated area.

Orthodontic brackets removal under shear and tensile bond strength resistance tests - a comparative test between light sources

NASA Astrophysics Data System (ADS)

Silva, P. C. G.; Porto-Neto, S. T.; Lizarelli, R. F. Z.; Bagnato, V. S.

2008-03-01

We have investigated if a new LEDs system has enough efficient energy to promote efficient shear and tensile bonding strength resistance under standardized tests. LEDs 470 ± 10 nm can be used to photocure composite during bracket fixation. Advantages considering resistance to tensile and shear bonding strength when these systems were used are necessary to justify their clinical use. Forty eight human extracted premolars teeth and two light sources were selected, one halogen lamp and a LEDs system. Brackets for premolar were bonded through composite resin. Samples were submitted to standardized tests. A comparison between used sources under shear bonding strength test, obtained similar results; however, tensile bonding test showed distinct results: a statistical difference at a level of 1% between exposure times (40 and 60 seconds) and even to an interaction between light source and exposure time. The best result was obtained with halogen lamp use by 60 seconds, even during re-bonding; however LEDs system can be used for bonding and re-bonding brackets if power density could be increased.

Heat dissipation investigation of the internal heat sink geometry of a commercial available LED lamp

NASA Astrophysics Data System (ADS)

Lai, S. L.; Ong, N. R.; Kirtsaeng, S.; Sakuntasathien, S.; Alcain, J. B.; Sauli, Z.; Thangsi, K.; Retnasamy, V.

2017-09-01

Thermal issue is still the bottleneck of the LED to sustain their operational performance. LED lamp is vastly commercialized and has become the next generation of lighting source to substitute the conventional incandescent lamp. Thus, thermal management issue on LED lamp is important to maintain the device reliability. This study focuses on the modification of internal heat sink of the LED lamp which was considered and the thermal performance was investigated. Open source software, Salome and Elmer were used for this study. The result shows that larger surface area of heat sink has better heat dissipation performance.

Interior LED Lighting Technology. Navy Energy Technology Validation (Techval) Program

DTIC Science & Technology

2015-09-01

usually on most of the time. • Consider replacing existing CFL, high-intensity discharge (HID), or halogen lamp light fixtures/ lamps with LED fixtures... lamps . What is the Technology? An LED is a semiconductor-diode that emits light when power is applied. A driver is used, much as a ballast, to...available in integrated luminaires that can be used to replace existing luminaires. LEDs are also available as direct replacement lamps for many

Comparative performance analysis of shunt and series passive filter for LED lamp

NASA Astrophysics Data System (ADS)

Sarwono, Edi; Facta, Mochammad; Handoko, Susatyo

2018-03-01

Light Emitting Diode lamp or LED lamp nowadays is widely used by consumers as a new innovation in the lighting technologies due to its energy saving for low power consumption lamps for brighter light intensity. How ever, the LED lamp produce an electric pollutant known as harmonics. The harmonics is generated by rectifier as part of LED lamp circuit. The present of harmonics in current or voltage has made the source waveform from the grid is distorted. This distortion may cause inacurrate measurement, mall function, and excessive heating for any element at the grid. This paper present an analysis work of shunt and series filters to suppress the harmonics generated by the LED lamp circuit. The work was initiated by conducting several tests to investigate the harmonic content of voltage and currents. The measurements in this work were carried out by using HIOKI Power Quality Analyzer 3197. The measurement results showed that the harmonics current of tested LED lamps were above the limit of IEEE standard 519-2014. Based on the measurement results shunt and series filters were constructed as low pass filters. The bode analysis were appled during construction and prediction of the filters performance. Based on experimental results, the application of shunt filter at input side of LED lamp has reduced THD current up to 88%. On the other hand, the series filter has significantly reduced THD current up to 92%.

Table lamp with dynamically controlled lighting distribution and uniformly illuminated luminous shade

DOEpatents

Siminovitch, Michael J.; Page, Erik R.

2002-01-01

A double lamp table or floor lamp lighting system has a pair of compact fluorescent lamps (CFLs) or other lamps arranged vertically, i.e. one lamp above the other, with a reflective septum in between. By selectively turning on one or both of the CFLs, down lighting, up lighting, or both up and down lighting is produced. The control system can also vary the light intensity from each CFL. The reflective septum ensures that almost all the light produced by each lamp will be directed into the desired light distribution pattern which is selected and easily changed by the user. In a particular configuration, the reflective septum is bowl shaped, with the upper CFL sitting in the bowl, and a luminous shade hanging down from the bowl. The lower CFL provides both task lighting and uniform shade luminance. Planar compact fluorescent lamps, e.g. circular CFLs, particularly oriented horizontally, are preferable. CFLs provide energy efficiency. However, other types of lamps, including incandescent, halogen, and LEDs can also be used in the fixture. The lighting system may be designed for the home, hospitality, office or other environments.

Monitoring of TiO2-catalytic UV-LED photo-oxidation of cyanide contained in mine wastewater and leachate.

PubMed

Kim, Seong Hee; Lee, Sang Woo; Lee, Gye Min; Lee, Byung-Tae; Yun, Seong-Taek; Kim, Soon-Oh

2016-01-01

A photo-oxidation process using UV-LEDs and TiO2 was studied for removal of cyanide contained in mine wastewater and leachates. This study focused on monitoring of a TiO2-catalyzed LED photo-oxidation process, particularly emphasizing the effects of TiO2 form and light source on the efficiency of cyanide removal. The generation of hydroxyl radicals was also examined during the process to evaluate the mechanism of the photo-catalytic process. The apparent removal efficiency of UV-LEDs was lower than that achieved using a UV-lamp, but cyanide removal in response to irradiation as well as consumption of electrical energy was observed to be higher for UV-LEDs than for UV-lamps. The Degussa P25 TiO2 showed the highest performance of the TiO2 photo-catalysts tested. The experimental results indicate that hydroxyl radicals oxidize cyanide to OCN(-), NO2(-), NO3(-), HCO3(-), and CO3(2-), which have lower toxicity than cyanide. In addition, the overall efficacy of the process appeared to be significantly affected by diverse operational parameters, such as the mixing ratio of anatase and rutile, the type of gas injected, and the number of UV-LEDs used. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Tong, Tao; Letoquin, Ronan; Keller, Bernd

An LED lamp or bulb is disclosed that comprises a light source, a heat sink structure and a remote planar phosphor carrier having at least one conversion material. The phosphor carrier can be remote to the light sources and mounted to the heat sink so that heat from the phosphor carrier spreads into the heat sink. The phosphor carrier can comprise a thermally conductive transparent material and a phosphor layer, with an LED based light source mounted to the heat sink such that light from the light source passes through the phosphor carrier. At least some of the LED lightmore » is converted by the phosphor carrier, with some lamp embodiments emitting a white light combination of LED and phosphor light. The phosphor arranged according to the present invention can operate at lower temperature to thereby operate at greater phosphor conversion efficiency and with reduced heat related damage to the phosphor.« less

CALiPER Report 21.3: Cost-Effectiveness of Linear (T8) LED Lamps

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

Miller, Naomi J.; Perrin, Tess E.; Royer, Michael P.

2014-05-27

Meeting performance expectations is important for driving adoption of linear LED lamps, but cost-effectiveness may be an overriding factor in many cases. Linear LED lamps cost more initially than fluorescent lamps, but energy and maintenance savings may mean that the life-cycle cost is lower. This report details a series of life-cycle cost simulations that compared a two-lamp troffer using LED lamps (38 W total power draw) or fluorescent lamps (51 W total power draw) over a 10-year study period. Variables included LED system cost ($40, $80, or $120), annual operating hours (2,000 hours or 4,000 hours), LED installation time (15more » minutes or 30 minutes), and melded electricity rate ($0.06/kWh, $0.12/kWh, $0.18/kWh, or $0.24/kWh). A full factorial of simulations allows users to interpolate between these values to aid in making rough estimates of economic feasibility for their own projects. In general, while their initial cost premium remains high, linear LED lamps are more likely to be cost-effective when electric utility rates are higher than average and hours of operation are long, and if their installation time is shorter.« less

CALiPER Report 21.3. Cost Effectiveness of Linear (T8) LED Lamps

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

None

2014-05-01

Meeting performance expectations is important for driving adoption of linear LED lamps, but cost-effectiveness may be an overriding factor in many cases. Linear LED lamps cost more initially than fluorescent lamps, but energy and maintenance savings may mean that the life-cycle cost is lower. This report details a series of life-cycle cost simulations that compared a two-lamp troffer using LED lamps (38 W total power draw) or fluorescent lamps (51 W total power draw) over a 10-year study period. Variables included LED system cost ($40, $80, or $120), annual operating hours (2,000 hours or 4,000 hours), LED installation time (15more » minutes or 30 minutes), and melded electricity rate ($0.06/kWh, $0.12/kWh, $0.18/kWh, or $0.24/kWh). A full factorial of simulations allows users to interpolate between these values to aid in making rough estimates of economic feasibility for their own projects. In general, while their initial cost premium remains high, linear LED lamps are more likely to be cost-effective when electric utility rates are higher than average and hours of operation are long, and if their installation time is shorter.« less

Light-emitting diodes as an illumination source for plants: a review of research at Kennedy Space Center

NASA Technical Reports Server (NTRS)

Kim, Hyeon-Hye; Wheeler, Raymond M.; Sager, John C.; Yorio, Neil C.; Goins, Gregory D.

2005-01-01

The provision of sufficient light is a fundamental requirement to support long-term plant growth in space. Several types of electric lamps have been tested to provide radiant energy for plants in this regard, including fluorescent, high-pressure sodium, and metal halide lamps. These lamps vary in terms of spectral quality, which can result in differences in plant growth and morphology. Current lighting research for space-based plant culture is focused on innovative lighting technologies that demonstrate high electrical efficiency and reduced mass and volume. Among the lighting technologies considered for space are light-emitting diodes (LEDs). The combination of red and blue LEDs has proven to be an effective lighting source for several crops, yet the appearance of plants under red and blue lighting is purplish gray, making visual assessment of plant health difficult. Additional green light would make the plant leaves appear green and normal, similar to a natural setting under white light, and may also offer psychological benefits for the crew. The addition of 24% green light (500-600 nm) to red and blue LEDs enhanced the growth of lettuce plants compared with plants grown under cool white fluorescent lamps. Coincidentally, these plants grown under additional green light would have the additional aesthetic appeal of a green appearance.

LED traffic signal lamp characteristics : executive summary.

DOT National Transportation Integrated Search

2002-05-01

LED traffic signal lamps are being used to replace incandescent traffic signal lamps because of the long-term cost saving associated with reduced energy consumption and longer service life. The are reasons to believe that the use of LED traffic signa...

LED traffic signal lamp characteristics : final report.

DOT National Transportation Integrated Search

2002-05-01

LED traffic signal lamps are being used to replace incandescent traffic signal lamps because of : the long-term cost saving associated with reduced energy consumption and longer service life. The are reasons to believe that the use of LED traffic sig...

CALiPER Retail Lamps Study 3.1: Dimming, Flicker, and Power Quality Characteristics of LED A Lamps

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

none,

2014-12-31

This CALiPER report examines the characteristics of a subset of lamps from CALiPER Retail Lamps Study 3 in more detail. Specifically, it focuses on the dimming, power quality, and flicker characteristics of 14 LED A lamps, as controlled by four different retail-available dimmers.

Optical design of a street lamp based on dual-module chip-on-board LED arrays.

PubMed

Ge, Aiming; Cai, Jinlin; Chen, Dehua; Shu, Hongyun; Qiu, Peng; Wang, Junwei; Zhu, Ling

2014-09-01

We design and propose a compact street lamp based on dual-module chip-on-board LED. The street lamp is composed of six faceted reflectors. It can direct the luminous flux and form uniform illumination on the target area, and it effectively reduces power consumption. We have conducted both simulations and prototype measurements. The test results show good optical performance in that the uniformity of luminance reaches 0.58 for LED lamp zigzag arrangements and 0.60 for LED lamp double-side arrangements. The average luminance can fulfill the requirements in Chinese road lighting Standard CJJ45-2006.

Optimizing illumination in the greenhouse using a 3D model of tomato and a ray tracer

PubMed Central

de Visser, Pieter H. B.; Buck-Sorlin, Gerhard H.; van der Heijden, Gerie W. A. M.

2014-01-01

Reduction of energy use for assimilation lighting is one of the most urgent goals of current greenhouse horticulture in the Netherlands. In recent years numerous lighting systems have been tested in greenhouses, yet their efficiency has been very difficult to measure in practice. This simulation study evaluated a number of lighting strategies using a 3D light model for natural and artificial light in combination with a 3D model of tomato. The modeling platform GroIMP was used for the simulation study. The crop was represented by 3D virtual plants of tomato with fixed architecture. Detailed data on greenhouse architecture and lamp emission patterns of different light sources were incorporated in the model. A number of illumination strategies were modeled with the calibrated model. Results were compared to the standard configuration. Moreover, adaptation of leaf angles was incorporated for testing their effect on light use efficiency (LUE). A Farquhar photosynthesis model was used to translate the absorbed light for each leaf into a produced amount of carbohydrates. The carbohydrates produced by the crop per unit emitted light from sun or high pressure sodium lamps was the highest for horizontal leaf angles or slightly downward pointing leaves, and was less for more upward leaf orientations. The simulated leaf angles did not affect light absorption from inter-lighting LED modules, but the scenario with LEDs shining slightly upward (20°) increased light absorption and LUE relative to default horizontal beaming LEDs. Furthermore, the model showed that leaf orientation more perpendicular to the string of LEDs increased LED light interception. The combination of a ray tracer and a 3D crop model could compute optimal lighting of leaves by quantification of light fluxes and illustration by rendered lighting patterns. Results indicate that illumination efficiency increases when the lamp light is directed at most to leaves that have a high photosynthetic potential. PMID:24600461

Quantification and analysis of color stability based on thermal transient behavior in white LED lamps.

PubMed

Nisa Khan, M

2017-09-20

We present measurement and analysis of color stability over time for two categories of white LED lamps based on their thermal management scheme, which also affects their transient lumen depreciation. We previously reported that lumen depreciation in LED lamps can be minimized by properly designing the heat sink configuration that allows lamps to reach a thermal equilibrium condition quickly. Although it is well known that lumen depreciation degrades color stability of white light since color coordinates vary with total lumen power by definition, quantification and characterization of color shifts based on thermal transient behavior have not been previously reported in literature for LED lamps. Here we provide experimental data and analysis of transient color shifts for two categories of household LED lamps (from a total of six lamps in two categories) and demonstrate that reaching thermal equilibrium more quickly provides better stability for color rendering, color temperature, and less deviation of color coordinates from the Planckian blackbody locus line, which are all very important characterization parameters of color for white light. We report for the first time that a lamp's color degradation from the turn-on time primarily depends on thermal transient behavior of the semiconductor LED chip, which experiences a wavelength shift as well as a decrease in its dominant wavelength peak value with time, which in turn degrades the phosphor conversion. For the first time, we also provide a comprehensive quantitative analysis that differentiates color degradation due to the heat rise in GaN/GaInN LED chips and subsequently the boards these chips are mounted on-from that caused by phosphor heating in a white LED module. Finally, we briefly discuss why there are some inevitable trade-offs between omnidirectionality and color and luminous output stability in current household LED lamps and what will help eliminate these trade-offs in future lamp designs.

Alternatives to Pyrotechnic Distress Signals; Supplemental Report

DTIC Science & Technology

2015-08-01

distribution of an incandescent lamp as compared to a specific white LED . ...................... 3  Figure 3. Spectral distribution of a “cool” white LED ...of common lamps2. Figure 2 shows the spectral distribution of an incandescent lamp as compared to a “cool” white LED . Note the LED peak intensity in...project effort that developed a specification for a light-emitting diode ( LED ) signal characteristic as an alternative to pyrotechnic, maritime

The Effects of Lamp Spectral Distribution on Sky Glow over Observatories

DTIC Science & Technology

2015-01-01

overhead sky glow as a function of distance up to 300 km, from a variety of lamp types, including common gas discharge lamps and several types of LED...distance up to 300 km, from a variety of lamp types, in- cluding common gas discharge lamps and several types of LED lamps . We conclude for both...MAR 2015 2. REPORT TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE The Effects of Lamp Spectral Distribution on Sky Glow

Lumen degradation analysis of LED lamps based on the subsystem isolation method.

PubMed

Ke, Hong-Liang; Hao, Jian; Tu, Jian-Hui; Miao, Pei-Xian; Wang, Chao-Quan; Cui, Jing-Zhong; Sun, Qiang; Sun, Ren-Tao

2018-02-01

The lumen degradation of LED lamps undergoing an accelerated aging test is investigated. The entire LED lamp is divided into three subsystems, namely, driver, lampshade, and LED light source. The parameters of output power [Watts (W)], transmittance (%), and lumen flux (lm) are adopted in the analysis of the degradation of the driver, lampshade, and LED light source, respectively. Two groups of LED lamps are aged under the ambient temperatures of 25°C and 85°C, respectively, with the aging time of 2000 h. The lumen degradation of the lamps is from 3.8% to 4.9% for the group under a temperature of 25°C and from 10.6% to 12.7% for the group under a temperature of 85°C. The LED light source is the most aggressive part of the three subsystems, which accounts for 70.5% of the lumen degradation of the LED lamp on average. The lampshade is the second degradation source, which causes 21.5% of the total amount on average. The driver is the third degradation source, which causes 6.5% under 25°C and 2.8% under 85°C of the total amount on average.

A high-performance doped photocatalysts for inactivation of total coliforms in superficial waters using different sources of radiation.

PubMed

Claro, Elis Marina Turini; Bidoia, Ederio Dino; de Moraes, Peterson Bueno

2016-07-15

Photocatalytic water treatment has a currently elevated electricity demand and maintenance costs, but the photocatalytic water treatment may also assist in overcoming the limitations and drawbacks of conventional water treatment processes. Among the Advanced Oxidation Processes, heterogeneous photocatalysis is one of the most widely and efficiently used processes to degrade and/or remove a wide range of polluting compounds. The goal of this work was to find out a highly efficient photocatalytic disinfection process in superficial water with different doped photocatalysts and using three sources of radiation: mercury vapor lamp, solar simulator and UV-A LED. Three doped photocatalysts were prepared, SiZnO, NSiZnO and FNSiZnO. The inactivation efficiency of each synthesized photocatalysts was compared to a TiO2 P25 (Degussa(®)) 0.5 g L(-1) control. Photolysis inactivation efficiency was 85% with UV-A LED, which is considered very high, demanding low electricity consumption in the process, whereas mercury vapor lamp and solar simulator yielded 19% and 13% inactivation efficiency, respectively. The best conditions were found with photocatalysts SiZnO, FNSiZnO and NSiZnO irradiated with UV-A LED, where efficiency exceeded 95% that matched inactivation of coliforms using the same irradiation and photocatalyst TiO2. All photocatalysts showed photocatalytic activity with all three radiation sources able to inactivate total coliforms from river water. The use of UV-A LED as the light source without photocatalyst is very promising, allowing the creation of cost-effective and highly efficient water treatment plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Visual performance for trip hazard detection when using incandescent and led miner cap lamps.

PubMed

Sammarco, John J; Gallagher, Sean; Reyes, Miguel

2010-04-01

Accident data for 2003-2007 indicate that slip, trip, and falls (STFs) are the second leading accident class (17.8%, n=2,441) of lost-time injuries in underground mining. Proper lighting plays a critical role in enabling miners to detect STF hazards in this environment. Often, the only lighting available to the miner is from a cap lamp worn on the miner's helmet. The focus of this research was to determine if the spectral content of light from light-emitting diode (LED) cap lamps enabled visual performance improvements for the detection of tripping hazards as compared to incandescent cap lamps that are traditionally used in underground mining. A secondary objective was to determine the effects of aging on visual performance. The visual performance of 30 subjects was quantified by measuring each subject's speed and accuracy in detecting objects positioned on the floor both in the near field, at 1.83 meters, and far field, at 3.66 meters. Near field objects were positioned at 0 degrees and +/-20 degrees off axis, while far field objects were positioned at 0 degrees and +/-10 degrees off axis. Three age groups were designated: group A consisted of subjects 18 to 25 years old, group B consisted of subjects 40 to 50 years old, and group C consisted of subjects 51 years and older. Results of the visual performance comparison for a commercially available LED, a prototype LED, and an incandescent cap lamp indicate that the location of objects on the floor, the type of cap lamp used, and subject age all had significant influences on the time required to identify potential trip hazards. The LED-based cap lamps enabled detection times that were an average of 0.96 seconds faster compared to the incandescent cap lamp. Use of the LED cap lamps resulted in average detection times that were about 13.6% faster than those recorded for the incandescent cap lamp. The visual performance differences between the commercially available LED and prototype LED cap lamp were not statistically significant. It can be inferred from this data that the spectral content from LED-based cap lamps could enable significant visual performance improvements for miners in the detection of trip hazards. Published by Elsevier Ltd.

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

Tuenge, Jason R.; Hollomon, Brad; Dillon, Heather E.

This report covers the third part of a larger U.S. Department of Energy (DOE) project to assess the life-cycle environmental and resource impacts in the manufacturing, transport, use, and disposal of light-emitting diode (LED) lighting products in relation to incumbent lighting technologies. All three reports are available on the DOE website (www.ssl.energy.gov/tech_reports.html). • Part 1: Review of the Life-Cycle Energy Consumption of Incandescent, Compact Fluorescent and LED Lamps; • Part 2: LED Manufacturing and Performance; • Part 3: LED Environmental Testing. Parts 1 and 2 were published in February and June 2012, respectively. The Part 1 report included a summarymore » of the life-cycle assessment (LCA) process and methodology, provided a literature review of more than 25 existing LCA studies of various lamp types, and performed a meta-analysis comparing LED lamps with incandescent and compact fluorescent lamps (CFLs). Drawing from the Part 1 findings, Part 2 performed a more detailed assessment of the LED manufacturing process and used these findings to provide a comparative LCA taking into consideration a wider range of environmental impacts. Both reports concluded that the life-cycle environmental impact of a given lamp is dominated by the energy used during lamp operation—the upstream generation of electricity drives the total environmental footprint of the product. However, a more detailed understanding of end-of-life disposal considerations for LED products has become increasingly important as their installation base has grown. The Part 3 study (reported herein) was undertaken to augment the LCA findings with chemical analysis of a variety of LED, CFL, and incandescent lamps using standard testing procedures. A total of 22 samples, representing 11 different models, were tested to determine whether any of 17 elements were present at levels exceeding California or Federal regulatory thresholds for hazardous waste. Key findings include: • The selected models were generally found to be below thresholds for Federally regulated elements; • All CFLs and LED lamps and most incandescent lamps exceeded California thresholds for Copper; • Most CFL samples exceeded California thresholds for Antimony and Nickel, and half of the LED samples exceeded California thresholds for Zinc; • The greatest contributors were the screw bases, drivers, ballasts, and wires or filaments; • Overall concentrations in LED lamps were comparable to cell phones and other types of electronic devices, and were generally attributable to components other than the internal LED light sources; • Although the life-cycle environmental impact of the LED lamps is favorable when compared to CFLs and incandescent lamps, recycling will likely gain importance as consumer adoption increases. This study was exploratory in nature and was not intended to provide a definitive indication of regulatory compliance for any specific lamp model or technology. Further study would be needed to more broadly characterize the various light source technologies; to more accurately and precisely characterize a specific model; or to determine whether product redesign would be appropriate.« less

Whole high-quality light environment for humans and plants

NASA Astrophysics Data System (ADS)

Sharakshane, Anton

2017-11-01

Plants sharing a single light environment on a spaceship with a human being and bearing a decorative function should look as natural and attractive as possible. And consequently they can be illuminated only with white light with a high color rendering index. Can lighting optimized for a human eye be effective and appropriate for plants? Spectrum-based effects have been compared under artificial lighting of plants by high-pressure sodium lamps and general-purpose white LEDs. It has been shown that for the survey sample phytochrome photo-equilibria does not depend significantly on the parameters of white LED light, while the share of phytoactive blue light grows significantly as the color temperature increases. It has been revealed that yield photon flux is proportional to luminous efficacy and increases as the color temperature decreases, general color rendering index Ra and the special color rendering index R14 (green leaf) increase. General-purpose white LED lamps with a color temperature of 2700 K, Ra > 90 and luminous efficacy of 100 lm/W are as efficient as the best high-pressure sodium lamps, and at a higher luminous efficacy their yield photon flux per joule is even bigger in proportion. Here we show that demand for high color rendering white LED light is not contradictory to the agro-technical objectives.

Dual LED/incandescent security fixture

DOEpatents

Gauna, Kevin Wayne

2005-06-21

A dual LED and incandescent security lighting system uses a hybrid approach to LED illumination. It combines an ambient LED illuminator with a standard incandescent lamp on a motion control sensor. The LED illuminator will activate with the onset of darkness (daylight control) and typically remain on during the course of the night ("always on"). The LED illumination, typically amber, is sufficient to provide low to moderate level lighting coverage to the wall and ground area adjacent to and under the fixture. The incandescent lamp is integrated with a motion control circuit and sensor. When movement in the field of view is detected (after darkness), the incandescent lamp is switched on, providing an increased level of illumination to the area. Instead of an "always on" LED illuminator, the LEDs may also be switched off when the incandescent lamp is switched on.

LED lamp color control system and method

DOEpatents

Gaines, James; Clauberg, Bernd; Van Erp, Josephus A.M.

2013-02-05

An LED lamp color control system and method including an LED lamp having an LED controller 58; and a plurality of LED channels 60 operably connected to the LED controller 58, each of the plurality of LED channels 60 having a channel switch 62 in series with at least one shunted LED circuit 83, the shunted LED circuit 83 having a shunt switch 68 in parallel with an LED source 80. The LED controller 58 determines whether the LED source 80 is in a feedback controllable range, stores measured optical flux for the LED source 80 when the LED source 80 is in the feedback controllable range, and bypasses storing the measured optical flux when the LED source 80 is not in the feedback controllable range.

Constraints on drivers for visible light communications emitters based on energy efficiency.

PubMed

Del Campo-Jimenez, Guillermo; Perez-Jimenez, Rafael; Lopez-Hernandez, Francisco Jose

2016-05-02

In this work we analyze the energy efficiency constraints on drivers for Visible light communication (VLC) emitters. This is the main reason why LED is becoming the main source of illumination. We study the effect of the waveform shape and the modulation techniques on the overall energy efficiency of an LED lamp. For a similar level of illumination, we calculate the emitter energy efficiency ratio η (P_LED/P_TOTAL) for different signals. We compare switched and sinusoidal signals and analyze the effect of both OOK and OFDM modulation techniques depending on the power supply adjustment, level of illumination and signal amplitude distortion. Switched and OOK signals present higher energy efficiency behaviors (0.86≤η≤0.95) than sinusoidal and OFDM signals (0.53≤η≤0.79).

Efficient photochemical generation of peroxycarboxylic nitric anhydrides with ultraviolet light-emitting diodes

NASA Astrophysics Data System (ADS)

Rider, N. D.; Taha, Y. M.; Odame-Ankrah, C. A.; Huo, J. A.; Tokarek, T. W.; Cairns, E.; Moussa, S. G.; Liggio, J.; Osthoff, H. D.

2015-07-01

Photochemical sources of peroxycarboxylic nitric anhydrides (PANs) are utilized in many atmospheric measurement techniques for calibration or to deliver an internal standard. Conventionally, such sources rely on phosphor-coated low-pressure mercury (Hg) lamps to generate the UV light necessary to photo-dissociate a dialkyl ketone (usually acetone) in the presence of a calibrated amount of nitric oxide (NO) and oxygen (O2). In this manuscript, a photochemical PAN source in which the Hg lamp has been replaced by arrays of ultraviolet light-emitting diodes (UV-LEDs) is described. The output of the UV-LED source was analyzed by gas chromatography (PAN-GC) and thermal dissociation cavity ring-down spectroscopy (TD-CRDS). Using acetone, diethyl ketone (DIEK), diisopropyl ketone (DIPK), or di-n-propyl ketone (DNPK), respectively, the source produces peroxyacetic (PAN), peroxypropionic (PPN), peroxyisobutanoic (PiBN), or peroxy-n-butanoic nitric anhydride (PnBN) from NO in high yield (> 90 %). Box model simulations with a subset of the Master Chemical Mechanism (MCM) were carried out to rationalize product yields and to identify side products. The present work demonstrates that UV-LED arrays are a viable alternative to current Hg lamp setups.

Integrated photocatalytic filtration array for indoor air quality control.

PubMed

Denny, Frans; Permana, Eric; Scott, Jason; Wang, Jing; Pui, David Y H; Amal, Rose

2010-07-15

Photocatalytic and filtration technologies were integrated to develop a hybrid system capable of removing and oxidizing organic pollutants from an air stream. A fluidized bed aerosol generator (FBAG) was adapted to prepare TiO(2)-loaded ventilation filters for the photodegradation of gas phase ethanol. Compared to a manually loaded filter, the ethanol photodegradation rate constant for the FBAG coated filter increased by 361%. Additionally, the presence of the photogenerated intermediate product, acetaldehyde, was reduced and the time for mineralization to CO(2) was accelerated. These improvements were attributed to the FBAG system providing a more uniform distribution of TiO(2) particles across the filter surface leading to greater accessibility by the UV light. A dual-UV-lamp system, as opposed to a single-lamp system, enhanced photocatalytic filter performance demonstrating the importance of high light irradiance and light distribution across the filter surface. Substituting the blacklight blue lamps with a UV-light-emitting-diode (UV-LED) array led to further improvement as well as suppressed the electrical energy per order (EE/O) by a factor of 6. These improvements derived from the more uniform distribution of light irradiance as well as the higher efficiency of UV-LEDs in converting electrical energy to photons.

Photodynamic therapy using a novel irradiation source, LED lamp, is similarly effective to photodynamic therapy using diode laser or metal-halide lamp on DMBA- and TPA-induced mouse skin papillomas.

PubMed

Takahashi, Hidetoshi; Nakajima, Susumu; Ogasawara, Koji; Asano, Ryuji; Nakae, Yoshinori; Sakata, Isao; Iizuka, Hajime

2014-08-01

Photodynamic therapy (PDT) is useful for superficial skin tumors such as actinic keratosis and Bowen disease. Although PDT is non-surgical and easily-performed treatment modality, irradiation apparatus is large and expensive. Using 7, 12-dimethylbenz[a]anthracene (DMBA) and 12-ο-tetradecanoylphorbol-13-acetate (TPA)-induced mouse skin papilloma model, we compared the efficacy of TONS501- and ALA-PDT with a LED lamp, a diode laser lamp or a metal-halide lamp on the skin tumor regression. TONS501-PDT using 660 nm LED lamp showed anti-tumor effect at 1 day following the irradiation and the maximal anti-tumor effect was observed at 3 days following the irradiation. There was no significant difference in the anti-tumor effects among TONS501-PDT using LED, TONS501-PDT using diode laser, and 5-aminolevulinic acid hydrochloride (ALA)-PDT using metal-halide lamp. Potent anti-tumor effect on DMBA- and TPA-induced mouse skin papilloma was observed by TONS501-PDT using 660 nm LED, which might be more useful for clinical applications. © 2014 Japanese Dermatological Association.

Method of Reproduction of the Luminous Flux of the LED Light Sources by a Spherical Photometer

NASA Astrophysics Data System (ADS)

Huriev, M.; Neyezhmakov, P.

2018-02-01

In connection with transition to energy-efficient temporally stable light-emitting diodes (LEDs) lighting, a problem of ensuring the traceability of results of measurement of characteristics of light sources arises. The problem is related to existing measurement standards of luminous flux based on spherical photometers optimized for the reference incandescent lamps with a relative spectral characteristic different from the spectrum of the LEDs. We propose a method for reproduction of the luminous flux, which solves this problem.

Ultraviolet light-emitting diodes in water disinfection.

PubMed

Vilhunen, Sari; Särkkä, Heikki; Sillanpää, Mika

2009-06-01

The novel system of ultraviolet light-emitting diodes (UV LEDs) was studied in water disinfection. Conventional UV lamps, like mercury vapor lamp, consume much energy and are considered to be problem waste after use. UV LEDs are energy efficient and free of toxicants. This study showed the suitability of LEDs in disinfection and provided information of the effect of two emitted wavelengths and different test mediums to Escherichia coli destruction. Common laboratory strain of E. coli (K12) was used and the effects of two emitted wavelengths (269 and 276 nm) were investigated with two photolytic batch reactors both including ten LEDs. The effects of test medium were examined with ultrapure water, nutrient and water, and nutrient and water with humic acids. Efficiency of reactors was almost the same even though the one emitting higher wavelength had doubled optical power compared to the other. Therefore, the effect of wavelength was evident and the radiation emitted at 269 nm was more powerful. Also, the impact of background was studied and noticed to have only slight deteriorating effect. In the 5-min experiment, the bacterial reduction of three to four log colony-forming units (CFU) per cubic centimeter was achieved, in all cases. When turbidity of the test medium was greater, part of the UV radiation was spent on the absorption and reactions with extra substances on liquid. Humic acids can also coat the bacteria reducing the sensitivity of the cells to UV light. The lower wavelength was distinctly more efficient when the optical power is considered, even though the difference of wavelengths was small. The reason presumably is the greater absorption of DNA causing more efficient bacterial breakage. UV LEDs were efficient in E. coli destruction, even if LEDs were considered to have rather low optical power. The effect of wavelengths was noticeable but the test medium did not have much impact. This study found UV LEDs to be an optimal method for bacterial disinfection. The emitted wavelength was found to be an essential factor when using LEDs; thus, care should be taken in selecting the proper LED for maximum disinfection.

Max Tech and Beyond: Fluorescent Lamps

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

Scholand, Michael

2012-04-01

Fluorescent lamps are the most widely used artificial light source today, responsible for approximately 70% of the lumens delivered to our living spaces globally. The technology was originally commercialized in the 1930's, and manufacturers have been steadily improving the efficacy of these lamps over the years through modifications to the phosphors, cathodes, fill-gas, operating frequency, tube diameter and other design attributes. The most efficient commercially available fluorescent lamp is the 25 Watt T5 lamp. This lamp operates at 114-116 lumens per watt while also providing good color rendering and more than 20,000 hours of operating life. Industry experts interviewed indicatedmore » that while this lamp is the most efficient in the market today, there is still a further 10 to 14% of potential improvements that may be introduced to the market over the next 2 to 5 years. These improvements include further developments in phosphors, fill-gas, cathode coatings and ultraviolet (UV) reflective glass coatings. The commercialization of these technology improvements will combine to bring about efficacy improvements that will push the technology up to a maximum 125 to 130 lumens per watt. One critical issue raised by researchers that may present a barrier to the realization of these improvements is the fact that technology investment in fluorescent lamps is being reduced in order to prioritize research into light emitting diodes (LEDs) and ceramic metal halide high intensity discharge (HID) lamps. Thus, it is uncertain whether these potential efficacy improvements will be developed, patented and commercialized. The emphasis for premium efficacy will continue to focus on T5 lamps, which are expected to continue to be marketed along with the T8 lamp. Industry experts highlighted the fact that an advantage of the T5 lamp is the fact that it is 40% smaller and yet provides an equivalent lumen output to that of a T8 or T12 lamp. Due to its smaller form factor, the T5 lamp contains less material (i.e., glass, fill gas and phosphor), and has a higher luminance, enabling fixtures to take advantage of the smaller lamp size to improve the optics and provide more efficient overall system illuminance. In addition to offering the market a high-quality efficacious light source, another strong value proposition of fluorescent lighting is its long operating life. In today's market, one manufacturer is offering fluorescent lamps that have a rated life of 79,000 hours - which represents 18 years of service at 12 hours per day, 365 days per year. These lamps, operated using a long-life ballast specified by the manufacturer, take advantage of improvements in cathode coatings, fill gas chemistry and pressure to extend service life by a factor of four over conventional fluorescent lamps. It should be noted that this service life is also longer (approximately twice as long) as today's high-quality LED products. The fluorescent market is currently focused on the T5 and T8 lamp diameters, and it is not expected that other diameters would be introduced. Although T8 is a more optimal diameter from an efficacy perspective, the premium efficiency and optimization effort has been focused on T5 lamps because they are 40% smaller than T8, and are designed to operate at a higher temperature using high-frequency electronic ballasts. The T5 lamp offers savings in terms of materials, packaging and shipping, as well as smaller fixtures with improved optical performance. Manufacturers are actively researching improvements in four critical areas that are expected to yield additional efficacy improvements of approximately 10 to 14 percent over the next five years, ultimately achieving approximately 130 lumens per watt by 2015. The active areas of research where these improvements are anticipated include: (1) Improved phosphors which continue to be developed and patented, enabling higher efficacies as well as better color rendering and lumen maintenance; (2) Enhanced fill gas - adjusting proportions of argon, krypton, neon and xenon to optimize performance, while also minimizing the mercury dose; (3) Improved cathode coatings to enhance electron emissivity and extend lamp life; and (4) UV-reflective glass coatings deposited between the layer of phosphor and the glass tube, to reflect any UV light back into the phosphor layer for down-conversion.« less

CALiPER Report 20.3: Robustness of LED PAR38 Lamps

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

Poplawski, Michael E.; Royer, Michael P.; Brown, Charles C.

2014-12-01

Three samples of 40 of the Series 20 PAR38 lamps underwent multi-stress testing, whereby samples were subjected to increasing levels of simultaneous thermal, humidity, electrical, and vibrational stress. The results do not explicitly predict expected lifetime or reliability, but they can be compared with one another, as well as with benchmark conventional products, to assess the relative robustness of the product designs. On average, the 32 LED lamp models tested were substantially more robust than the conventional benchmark lamps. As with other performance attributes, however, there was great variability in the robustness and design maturity of the LED lamps. Severalmore » LED lamp samples failed within the first one or two levels of the ten-level stress plan, while all three samples of some lamp models completed all ten levels. One potential area of improvement is design maturity, given that more than 25% of the lamp models demonstrated a difference in failure level for the three samples that was greater than or equal to the maximum for the benchmarks. At the same time, the fact that nearly 75% of the lamp models exhibited better design maturity than the benchmarks is noteworthy, given the relative stage of development for the technology.« less

Modeling Ultraviolet (UV) Light Emitting Diode (LED) Energy Propagation in Reactor Vessels

DTIC Science & Technology

2014-03-27

21 Table 4: UV Mercury Lamps , UV LED Bulbs, and Visible LED Bulb Advantages and Disadvantages...over low pressure mercury lamps include smaller size, minimal start up time, and no hazardous material. Projections show UV LEDs will follow similar

Tuning the white light spectrum of light emitting diode lamps to reduce attraction of nocturnal arthropods

PubMed Central

Longcore, Travis; Aldern, Hannah L.; Eggers, John F.; Flores, Steve; Franco, Lesly; Hirshfield-Yamanishi, Eric; Petrinec, Laina N.; Yan, Wilson A.; Barroso, André M.

2015-01-01

Artificial lighting allows humans to be active at night, but has many unintended consequences, including interference with ecological processes, disruption of circadian rhythms and increased exposure to insect vectors of diseases. Although ultraviolet and blue light are usually most attractive to arthropods, degree of attraction varies among orders. With a focus on future indoor lighting applications, we manipulated the spectrum of white lamps to investigate the influence of spectral composition on number of arthropods attracted. We compared numbers of arthropods captured at three customizable light-emitting diode (LED) lamps (3510, 2704 and 2728 K), two commercial LED lamps (2700 K), two commercial compact fluorescent lamps (CFLs; 2700 K) and a control. We configured the three custom LEDs to minimize invertebrate attraction based on published attraction curves for honeybees and moths. Lamps were placed with pan traps at an urban and two rural study sites in Los Angeles, California. For all invertebrate orders combined, our custom LED configurations were less attractive than the commercial LED lamps or CFLs of similar colour temperatures. Thus, adjusting spectral composition of white light to minimize attracting nocturnal arthropods is feasible; not all lights with the same colour temperature are equally attractive to arthropods. PMID:25780237

Whole high-quality light environment for humans and plants.

PubMed

Sharakshane, Anton

2017-11-01

Plants sharing a single light environment on a spaceship with a human being and bearing a decorative function should look as natural and attractive as possible. And consequently they can be illuminated only with white light with a high color rendering index. Can lighting optimized for a human eye be effective and appropriate for plants? Spectrum-based effects have been compared under artificial lighting of plants by high-pressure sodium lamps and general-purpose white LEDs. It has been shown that for the survey sample phytochrome photo-equilibria does not depend significantly on the parameters of white LED light, while the share of phytoactive blue light grows significantly as the color temperature increases. It has been revealed that yield photon flux is proportional to luminous efficacy and increases as the color temperature decreases, general color rendering index R a and the special color rendering index R 14 (green leaf) increase. General-purpose white LED lamps with a color temperature of 2700 K, R a  > 90 and luminous efficacy of 100 lm/W are as efficient as the best high-pressure sodium lamps, and at a higher luminous efficacy their yield photon flux per joule is even bigger in proportion. Here we show that demand for high color rendering white LED light is not contradictory to the agro-technical objectives. Copyright © 2017. Published by Elsevier Ltd.

Pulsed Ultraviolet Light Emitting Diodes for Advanced Oxidation of Tartrazine

DTIC Science & Technology

2015-03-26

a significantly lower amount of energy while lasting considerably longer than the conventional lamp . Recently, an experiment on AOP with a UV LED ...severe damage to these organs, resulting in death (OSHA, 2012). LEDs are promising alternatives for UV energy sources. Contrarily to mercury lamps ...Table 1 UV Lamp Properties Additionally, because LEDs interrupt the DNA of microorganisms without the introduction of added chemicals, there are

White LEDs as broad spectrum light sources for spectrophotometry: demonstration in the visible spectrum range in a diode-array spectrophotometric detector.

PubMed

Piasecki, Tomasz; Breadmore, Michael C; Macka, Mirek

2010-11-01

Although traditional lamps, such as deuterium lamps, are suitable for bench-top instrumentation, their compatibility with the requirements of modern miniaturized instrumentation is limited. This study investigates the option of utilizing solid-state light source technology, namely white LEDs, as a broad band spectrum source for spectrophotometry. Several white light LEDs of both RGB and white phosphorus have been characterized in terms of their emission spectra and energy output and a white phosphorus Luxeon LED was then chosen for demonstration as a light source for visible-spectrum spectrophotometry conducted in CE. The Luxeon LED was fixed onto the base of a dismounted deuterium (D(2) ) lamp so that the light-emitting spot was geometrically positioned exactly where the light-emitting spot of the original D(2) lamp is placed. In this manner, the detector of a commercial CE instrument equipped with a DAD was not modified in any way. As the detector hardware and electronics remained the same, the change of the deuterium lamp for the Luxeon white LED allowed a direct comparison of their performances. Several anionic dyes as model analytes with absorption maxima between 450 and 600 nm were separated by CE in an electrolyte of 0.01 mol/L sodium tetraborate. The absorbance baseline noise as the key parameter was 5 × lower for the white LED lamp, showing clearly superior performance to the deuterium lamp in the available, i.e. visible part of the spectrum. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inactivation of Nonpathogenic Escherichia coli, Escherichia coli O157:H7, Salmonella enterica Typhimurium, and Listeria monocytogenes in Ice Using a UVC Light-Emitting Diode.

PubMed

Murashita, Suguru; Kawamura, Shuso; Koseki, Shigenobu

2017-07-01

Ice, widely used in the food industry, is a potential cause of food poisoning resulting from microbial contamination. Direct microbial inactivation of ice is necessary because microorganisms may have been present in the source water used to make it and/or may have been introduced due to poor hygiene during production or handling of the ice. Nonthermal and nondestructive microbial inactivation technologies are needed to control microorganisms in ice. We evaluated the applicability of a UVC light-emitting diode (UVC-LED) for microbial inactivation in ice. The effects of UV intensity and UV dose of the UVC-LED on Escherichia coli ATCC 25922 and a comparison of UVC-LED with a conventional UV lamp for effective bacterial inactivation in distilled water and ice cubes were investigated to evaluate the performance of the UVC-LED. Finally, we assessed the effects of the UVC-LED on pathogens such as E. coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in ice cubes. The results indicated that UVC-LED effectiveness depended on the UV dose at all UV intensity conditions (0.084, 0.025, 0.013, 0.007, and 0.005 mW/cm 2 ) in ice and that UVC-LED could more efficiently inactivate E. coli ATCC 25922 in distilled water and ice than the UV lamp. At a UV dose of 2.64 mJ/cm 2 , E. coli in distilled water was decreased by 0.90 log CFU/mL (UV lamp) and by more than 7.0 log CFU/mL (UVC-LED). At 15.2 mJ/cm 2 , E. coli in ice was decreased by 3.18 log CFU/mL (UV lamp) and by 4.45 CFU/mL (UVC-LED). Furthermore, UVC-LED irradiation reduced the viable number of pathogens by 6 to 7 log cycles at 160 mJ/cm 2 , although the bactericidal effect was somewhat dependent on the type of bacteria. L. monocytogenes in ice was relatively more sensitive to UVC irradiation than were E. coli O157:H7 and Salmonella Typhimurium. These results demonstrate that UVC-LED irradiation could contribute to the safety of ice in the food industry.

Light Sources and Ballast Circuits

NASA Astrophysics Data System (ADS)

Yorifuji, Takashi; Sakai, Makoto; Yasuda, Takeo; Maehara, Akiyoshi; Okada, Atsunori; Gouriki, Takeshi; Mannami, Tomoaki

According to the machinery statistics by Ministry of Economy, Trade and Industry (METI), the total of domestic light bulb production in 2006 was 1,101 million (88.5% year-on-year). Production for general purpose illumination light bulbs and halogen light bulbs accounted for 122 million (99.2% y/y) and 45 million (96.3% y/y), respectively. The total of fluorescent lamp production was 988 million (114.9%) and the production of general purpose fluorescent lamps excluding backlights accounted for 367 million (101.7% y/y). Further, HID lamp production was 10 million (106.3% y/y). What is noteworthy regarding such lamp production is that, similar to the previous year, the sales volume (amount) of lamps for general illumination exceeded 100% against the previous year, indicating a steady shift to high value added products. Major lighting exhibitions in 2006 included the Light + Building Trade Fair held in Frankfurt in April and the Light Fair International 2006 held in Las Vegas, U.S.A. in May, both of which demonstrated signs of acceleration toward energy saving, high efficiency and resource saving. As for incandescent lamps, products filled with larger atomic weight gases aiming at higher efficiency/longer life are becoming the mainstream. As for new technologies, it was experimentally demonstrated that infrared radiation can be suppressed by processing micro cavities to metal plates made of tungsten, tantalum, etc. For fluorescent lamps, straight and circular fluorescent lamps achieving a longer life/higher luminous flux maintenance factor continued to be widely developed/launched again this year. For compact fluorescent lamps, energy saving/high efficiency products, multifunctional type products combined with LED and new shaped products were launched. As to HID lamps, ceramic metal halide lamps with high efficiency, improved color rendering, longer life and higher luminous flux maintenance factor were commercialized one after another. Numerous studies and analyses, on discharge models were reported. Further, studies on ultra high-pressure mercury lamps as light sources for projectors are becoming the mainstream of HID lamp related researches. For high-pressure sodium lamps, many studies on plant growing and pest control utilizing low insect attracting aspects were also reported in 2006. Additionally, for discharge lamps, the minimum sustaining electric power for arc tubes employed in electrode-less compact fluorescent lamps was investigated. For Hg-free rare-gas fluorescent lamps, a luminance of 10,000cd/m2 was attained by a 1 meter-long external duplex spiral electrode prototype using Xe/Ne barrier discharge. As to startup circuits, the commercialization of energy saving and high value added products mainly associated with fluorescent lamps and HID lamps are becoming common. Further, the miniaturization of startup circuits for self electronic-ballasted lamps has advanced. Speaking of the overall light sources and startup circuits in 2006 and with the enforcement of RoHS in Europe in July, the momentum toward hazardous substance-free and energy saving initiatives has been enhanced from the perspective of protecting the global environment. It is anticipated that similar restrictions will be globally enforced in the future.

Highly efficient all-nitride phosphor-converted white light emitting diode

NASA Astrophysics Data System (ADS)

Mueller-Mach, Regina; Mueller, Gerd; Krames, Michael R.; Höppe, Henning A.; Stadler, Florian; Schnick, Wolfgang; Juestel, Thomas; Schmidt, Peter

2005-07-01

The development and demonstration of a highly efficient warm-white all-nitride phosphor-converted light emitting diode (pc-LED) is presented utilizing a GaN based quantum well blue LED and two novel nitrogen containing luminescent materials, both of which are doped with Eu2+. For color conversion of the primary blue the nitridosilicates M2Si5N8 (orange-red) and MSi2O2N2 (yellow-green), with M = alkaline earth, were employed, thus achieving a high luminous efficiency (25 lumen/W at 1 W input), excellent color quality (correlated color temperature CCT = 3200 K, general color rendering index Ra > 90) and the highest proven color stability of any pc-LED obtained so far. Thus, these novel all-nitride LEDs are superior to both incandescent and fluorescent lamps and may therefore become the next generation of general lighting sources.

Types of Lamp for Homework and Myopia among Chinese School-Aged Children.

PubMed

Pan, Chen-Wei; Wu, Rong-Kun; Liu, Hu; Li, Jun; Zhong, Hua

2018-06-01

We aim to determine the association of the types of lamp for homework including incandescent lamp, fluorescent lamp, and light-emitting diode (LED) lamp with the prevalence of myopia in Chinese children. 2346 grade 7 students from ten middle schools (93.5% response rate) aged 13 to 14 years in Mojiang, a small county located in Southwestern China, participated in the study. Refractive error was measured with cycloplegia using an autorefractor by optometrists or trained technicians. An IOL Master was used to measure ocular biometric parameters including axial length (AL). Information regarding the types of lamp for homework af``ter schools was collected by questionnaires. Of all the study participants, 693 (29.5%) were affected by myopia, with the prevalence estimates being higher in girls (36.8%; 95% confidence interval [CI]: 34.0, 39.6) than in boys (22.8%; 95% CI: 20.4, 25.1) (P < 0.001). After adjusting for potential confounders such as gender, height, parental history of myopia, time on computer use, time on watching TV, time outdoors, and time on reading and writing, participants using LED lamps for homework had a more myopic refractive error and a longer AL compared with those using incandescent or fluorescent lamps. There were no significant differences in myopia prevalence between children using incandescent and fluorescent lamps for homework. The population attributable risk percentage for myopia associated with using LED lamps for homework after schools was 11.2%. Using LED lamps for homework after schools might contribute to the development of myopia among school-aged children.

Demonstration of LED Retrofit Lamps at the Smithsonian American Art Museum, Washington, DC

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

Miller, Naomi J.; Rosenfeld, Scott M.

This report documents observations and results obtained from a lighting demonstration project conducted under the U.S. Department of Energy GATEWAY Solid-State Lighting (SSL) Technology Demonstration Program at the Smithsonain American Art Museum in Washington, DC. LED Lamp samples were tested in the museum workshop, temporarily installed in a gallery for feedback, and ultimately replaced all traditional incandescent lamps in one gallery of modernist art at the American Art Museum and partially replacing lamps in two galleries at the Musesum's Renwick Gallery. This report describes the selection and testing process, technology challenges, perceptions, economics, energy use, and mixed results of usignmore » LED replacement lamps in art galleries housing national treasures.« less

CALiPER Report 22.1: Photoelectric Performance of LED MR16 Lamps

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

Royer, Michael P.; Poplawski, Michael E.; Brown, Charles C.

This report is a follow-up to CALiPER Application Summary Report 22, which investigated the photometric performance of LED MR16 lamps. The initial report found that many of the LED MR16 lamps did not perform as required by ENERGY STAR based on their equivalency claims, although they generally did provide substantial efficacy advantages compared to halogen MR16 lamps. All testing was completed using laboratory power supplies, with all but one product tested at 12 V AC. In contrast, this report examined the photoelectric performance of the same set of lamps, using commercially available transformers and dimmers as well as laboratory powermore » supplies providing both AC and DC power.« less

Anti-glare LED lamps with adjustable illumination light field.

PubMed

Chen, Yung-Sheng; Lin, Chung-Yi; Yeh, Chun-Ming; Kuo, Chie-Tong; Hsu, Chih-Wei; Wang, Hsiang-Chen

2014-03-10

We introduce a type of LED light-gauge steel frame lamp with an adjustable illumination light field that does not require a diffusion plate. Base on the Monte Carlo ray tracing method, this lamp has a good glare rating (GR) of 17.5 at 3050 lm. Compared with the traditional LED light-gauge steel frame lamp (without diffusion plate), the new type has low GR. The adjustability of the illumination light field could improve the zebra effect caused by the inadequate illumination light field of the lamp. Meanwhile, we adopt the retinal image analysis to discuss the influence of GR on vision. High GR could reflect stray light on the retinal image, which will reduce vision clarity and hasten the feeling of eye fatigue.

[Study on the safety of blue light leak of LED].

PubMed

Shen, Chong-Yu; Xu, Zheng; Zhao, Su-Ling; Huang, Qing-Yu

2014-02-01

In this paper, the blue light properties of LED illumination devices have been investigated. Against the status quo of China's LED lighting, we measured the spectrum component of LED lamps and analyzed the photobiological safety under the current domestic and international standards GB/T 20145-2006/CIE S009/E: 2002 and IEC62471: 2006 standards as well as CTL-0744_2009-laser resolution, which provides the reference to the manufacture of LED lighting lamps as well as related safety standards and laws. If the radiance intensity of blue light in LED is lower than 100 W x m(-2) x Sr(-1), there is no harm to human eyes. LEDs will not cause harm to human eyes under normal use, but we should pay attention to the protection of special populations (children), and make sure that they avoid looking at a light source for a long time. The research has found that the blue-rich lamps can affect the human rule of work and rest, and therefore, the LED lamps with color temperature below 4 000 K and color rendering index of 80 are suitable for indoor use. At the same time, the lamps with different parameters should be selected according to the different distances.

Efficient photochemical generation of peroxycarboxylic nitric anhydrides with ultraviolet light emitting diodes

NASA Astrophysics Data System (ADS)

Rider, N. D.; Taha, Y. M.; Odame-Ankrah, C. A.; Huo, J. A.; Tokarek, T. W.; Cairns, E.; Moussa, S. G.; Liggio, J.; Osthoff, H. D.

2015-01-01

Photochemical sources of peroxycarboxylic nitric anhydrides (PANs) are utilized in many atmospheric measurement techniques for calibration or to deliver an internal standard. Conventionally, such sources rely on phosphor-coated low-pressure mercury (Hg) lamps to generate the UV light necessary to photo-dissociate a dialkyl ketone (usually acetone) in the presence of a calibrated amount of nitric oxide (NO) and oxygen (O2). In this manuscript, a photochemical PAN source in which the Hg lamp has been replaced by arrays of ultraviolet light-emitting diodes (UV-LEDs) is described. The output of the UV-LED source was analyzed by gas chromatography (PAN-GC) and thermal dissociation cavity ring-down spectroscopy (TD-CRDS). Using acetone, diethyl ketone (DIEK), diisopropyl ketone (DIPK), or di-n-propyl ketone (DNPK), respectively, the source produces peroxyacetic (PAN), peroxypropionic (PPN), peroxyisobutanoic (PiBN), or peroxy-n-butanoic nitric anhydride (PnBN) from NO in high yield (> 90%). Box model simulations with a subset of the Master Chemical Mechanism (MCM) were carried out to rationalize products yields and to identify side products. The use of UV-LED arrays offers many advantages over conventional Hg lamp setups, including greater light output over a narrower wavelength range, lower power consumption, and minimal generation of heat.

Effect of various visible light photoinitiators on the polymerization and color of light-activated resins.

PubMed

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

2009-07-01

The purpose of this study was to investigate effects of various visible light photoinitiators on the polymerization efficiency and color of the light-activated resins. Four photoinitiators, including camphorquinone, phenylpropanedione, monoacrylphosphine oxide (TPO), and bisacrylphosphine oxide (Ir819), were used. Each photoinitiator was dissolved in a Bis-GMA and TEGDMA monomer mixture. Materials were polymerized using dental quartz-tungsten halogen lamp (QTH), plasma-ark lamp and blue LED light-curing units, and a custom-made violet LED light unit. The degree of monomer conversion and CIE L*a*b* color values of the resins were measured using a FTIR and spectral transmittance meter. The degree of monomer conversions of TPO- and Ir819-containing resins polymerized with the violet-LED unit were higher than camphorquinone-containing resin polymerized with the QTH light-curing unit. The lowest color values were observed for the TPO-containing resin. Our results indicate that the TPO photoinitiator and the violet-LED light unit may provide a useful and improved photopolymerization system for dental light-activated resins.

Comparative studies on dimming capabilities of retrofit LED lamps

NASA Astrophysics Data System (ADS)

Ionescu, Ciprian; Vasile, Alexandru; Codreanu, Norocel; Negroiu, Rodica

2016-12-01

These days many variants for lighting systems are available on the market, and new solutions are about to emerge. Most of the new lamps are offered in form to be retrofitted to existing sockets and luminaires. In this paper, are presented some systematically investigations on different lamps as LEDs, Compact Fluorescent Lamps (CFLs), tungsten, and new available Cold Cathode Fluorescent Lamps (CCFLs), regarding the light level, dimming performances and also the resulting flicker and power distortion performances. The light level was expressed by the illuminance level, measured for all lamps in the same conditions, at the same distance and on the same surface represented by the photometer probe.

CALiPER Application Summary Report 21. Linear (T8) LED Lamps

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

None

2014-03-01

This report focuses on the bare lamp performance of 31 linear LED lamps intended as an alternative to T8 fluorescent lamps. Data obtained in accordance with IES LM-79-08 indicated that the mean efficacy is similar to that of fluorescent lamps, but that lumen output is often much lower. This presents a situation where something must change in order for energy savings and equivalent illumination levels to be achieved simultaneously. In this case, the luminous intensity distribution of all the tested lamps was directional or semi-directional, rather than omnidirectional. Also discussed in this report are several issues related to the electricalmore » configuration of the lamps, such as the required socket types and power feed location. While no configuration is necessarily better, the multitude of options can make specifying and installing linear LED lamps more difficult, with the potential for safety issues. Similarly, the variety of color and power quality attributes adds a layer of complexity to the specification process. Many products offered good or excellent quality attributes, but some did not and thus could be perceived as inferior to fluorescent lamps in some installations.« less

Comparative Study of Lettuce and Radish Grown Under Red and Blue Light-Emitting Diodes (LEDs) and White Fluorescent Lamps

NASA Technical Reports Server (NTRS)

Mickens, Matthew A.

2012-01-01

Growing vegetable crops in space will be an essential part of sustaining astronauts during long-term missions. To drive photosynthesis, red and blue light-emitting diodes (LEDs) have attracted attention because of their efficiency, longevity, small size, and safety. In efforts to optimize crop production, there have also been recent interests in analyzing the subtle effects of green light on plant growth, and to determine if it serves as a source of growth enhancement or suppression. A comparative study was performed on two short cycle crops of lettuce (Outredgeous) and radish (Cherry Bomb) grown under two light treatments. The first treatment being red and blue LEDs, and the second treatment consisting of white fluorescent lamps which contain a portion of green light. In addition to comparing biomass production, physiological characterizations were conducted on how the light treatments influence morphology, water use, chlorophyll content, and the production of A TP within plant tissues.

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

Royer, Michael P.; McCullough, Jeffrey J.; Tucker, Joseph C.

The lumen depreciation and color shift of 17 different A lamps (15 LED, 1 CFL, 1 halogen) was monitored in the automated long-term test apparatus (ALTA) for more than 7,500 hours. Ten samples of each lamp model were tested, with measurements recorded on a weekly basis. The lamps were operated continuously at an ambient temperature of 45°C (-1°C). Importantly, the steady-state test conditions were not optimized for inducing catastrophic failure for any of the lamp technologies—to which thermal cycling is a strong contributor— and are not typical of normal use patterns—which usually include off periods where the lamp cools down.more » Further, the test conditions differ from those used in standardized long-term test methods (i.e., IES LM-80, IES LM-84), so the results should not be directly compared. On the other hand, the test conditions are similar to those used by ENERGY STAR (when elevated temperature testing is called for). Likewise, the conditions and assumptions used by manufacturers to generated lifetime claims may vary; the CALiPER long-term data is informative, but cannot necessarily be used to discredit manufacturer claims. The test method used for this investigation should be interpreted as one more focused on the long-term effects of elevated temperature operation, at an ambient temperature that is not uncommon in luminaires. On average, the lumen maintenance of the LED lamps monitored in the ALTA was better than benchmark lamps, but there was considerable variation from lamp model to lamp model. While three lamp models had average lumen maintenance above 99% at the end of the study period, two products had average lumen maintenance below 65%, constituting a parametric failure. These two products, along with a third, also exhibited substantial color shift, another form of parametric failure. While none of the LED lamps exhibited catastrophic failure—and all of the benchmarks did—the early degradation of performance is concerning, especially with a new technology trying to build a reputation with consumers. Beyond the observed parametric failures nearly half of the products failed to meet early-life thresholds for lumen maintenance, which were borrowed from ENERGY STAR specifications. That is, the lumen maintenance was sufficiently low at 6,000 hours that seven of the products are unlikely to have lumen maintenance above 70% at their rated lifetime (which was usually 25,000 hours). Given the methods used for this investigation—most notably continuous operation—the results should not be interpreted as indicative of a lamp’s performance in a typical environment. Likewise, these results are not directly relatable to manufacturer lifetime claims. This report is best used to understand the variation in LED product performance, compare the robustness of LED lamps and benchmark conventional lamps, and understand the characteristics of lumen and chromaticity change. A key takeaway is that the long-term performance of LED lamps can vary greatly from model to model (i.e., the technology is not homogenous), although the lamp-to-lamp consistency within a given model is relatively good. Further, operation of LED lamps in an enclosed luminaire (or otherwise in high ambient temperatures), can induce parametric failure of LEDs much earlier than their rated lifetime; manufacturer warnings about such conditions should be followed if performance degradation is unacceptable.« less

Application Summary Report 22: LED MR16 Lamps

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

Royer, Michael P.

2014-07-23

This report analyzes the independently tested photometric performance of 27 LED MR16 lamps. It describes initial performance based on light output, efficacy, distribution, color quality, electrical characteristics, and form factor, with comparisons to a selection of benchmark halogen MR16s and ENERGY STAR qualification thresholds. Three types of products were targeted. First, CALiPER sought 3000 K lamps with the highest rated lumen output (i.e., at least 500 lm) or a claim of equivalency to a 50 W halogen MR16 or higher. The test results indicate that while the initial performance of LED MR16s has improved across the board, market-available products stillmore » do not produce the lumen output and center beam intensity of typical 50 W halogen MR16 lamps. In fact, most of the 18 lamps in this category had lower lumen output and center beam intensity than a typical 35 W halogen MR16 lamp. Second, CALiPER sought lamps with a CRI of 90 or greater. Only four manufacturers were identified with a product in this category. CALiPER testing confirmed the performance of these lamps, which are a good option for applications where high color fidelity is needed. A vast majority of the LED MR16 lamps have a CRI in the low 80s; this is generally acceptable for ambient lighting, but may not always be acceptable for focal lighting. For typical LED packages, there is a fundamental tradeoff between CRI and efficacy, but the lamps in the high-CRI group in this report still offer comparable performance to the rest of the Series 22 products in other performance areas. Finally, CALiPER sought lamps with a narrow distribution, denoted as a beam angle less than 15°. Five such lamps were purchased. Notably, no lamp was identified as having high lumen output (500 lumens or greater), high CRI (90 or greater), a narrow distribution (15° or less), and an efficacy greater than 60 lm/W. This would be an important achievement for LED MR16s especially if output could reach approximately 700 800 lumens, or the approximate equivalent of a 50 W halogen MR16 lamp. Many factors beyond photometric performance should be considered during specification. For example, performance over time, transformer and dimmer compatibility, and total system performance are all critical to a successful installation. Subsequent CALiPER reports will investigate more complex issues.« less

Photochemical studies on aromatic γ,δ-epoxy ketones: efficient synthesis of benzocyclobutanones and indanones.

PubMed

Shao, Yutian; Yang, Chao; Gui, Weijun; Liu, Yang; Xia, Wujiong

2012-04-11

Irradiation of terminal aromatic γ,δ-epoxy ketones with a 450 W UV lamp led to Norrish type II cyclization/semi-pinacol rearrangement cascade reaction which formed the benzocyclobutanones containing a full-carbon quaternary center, whereas irradiation of substituted aromatic γ,δ-epoxy ketones led to the indanones through a photochemical epoxy rearrangement and 1,5-biradicals cyclization tandem reaction. This journal is © The Royal Society of Chemistry 2012

CALiPER Exploratory Study. Recessed Troffer Lighting

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

Miller, N. J.; Royer, M. P.; Poplawski, M. E.

This CALiPER study examines the problems and benefits likely to be encountered with LED products intended to replace linear fluorescent lamps. LED dedicated troffers, replacement tubes, and non-tube retrofit kits were evaluated against fluorescent benchmark troffers in a simulated office space for photometric distribution, uniformity of light on the task surface, suitability of light output, flicker, dimming performance, color quality, power quality, safety and certification issues, ease of installation, energy efficiency, and life-cycle cost.

Ultraviolet Light Emitting Diode Use in Advanced Oxidation Processes

DTIC Science & Technology

2014-03-27

or medium pressure mercury lamps , but UV light emitting diodes ( LEDs ) have the capacity to be used for water disinfection also. Traditional mercury...based upon the phosphors that are selected and used to coat the inside of the glass tube from which these lamps are produced. A UV LED is...Research has demonstrated the ability to use UV LEDs in place of mercury lamps to achieve the same 7 disinfection capacity, and limited research has

Evaluation of a LED-based flatbed document scanner for radiochromic film dosimetry in transmission mode.

PubMed

Lárraga-Gutiérrez, José Manuel; García-Garduño, Olivia Amanda; Treviño-Palacios, Carlos; Herrera-González, José Alfredo

2018-03-01

Flatbed scanners are the most frequently used reading instrument for radiochromic film dosimetry because its low cost, high spatial resolution, among other advantages. These scanners use a fluorescent lamp and a CCD array as light source and detector, respectively. Recently, manufacturers of flatbed scanners replaced the fluorescent lamp by light emission diodes (LED) as a light source. The goal of this work is to evaluate the performance of a commercial flatbed scanner with LED based source light for radiochromic film dosimetry. Film read out consistency, response uniformity, film-scanner sensitivity, long term stability and total dose uncertainty was evaluated. In overall, the performance of the LED flatbed scanner is comparable to that of a cold cathode fluorescent lamp (CCFL). There are important spectral differences between LED and CCFL lamps that results in a higher sensitivity of the LED scanner in the green channel. Total dose uncertainty, film response reproducibility and long-term stability of LED scanner are slightly better than those of the CCFL. However, the LED based scanner has a strong non-uniform response, up to 9%, that must be adequately corrected for radiotherapy dosimetry QA. The differences in light emission spectra between LED and CCFL lamps and its potential impact on film-scanner sensitivity suggest that the design of a dedicated flat-bed scanner with LEDs may improve sensitivity and dose uncertainty in radiochromic film dosimetry. Copyright © 2018 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Lumen and Chromaticity Maintenance of LED PAR38 Lamps Operated in Steady-State Conditions

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

Royer, Michael P.

2014-12-01

The lumen depreciation and color shift of 38 different lamps (32 LED, 2 CFL, 1 ceramic metal halide [CMH], 3 halogen) were monitored in a specially developed automated long-term test apparatus (ALTA2) for nearly 14,000 hours. Five samples of each lamp model were tested, with measurements recorded on a weekly basis. The lamps were operated continuously at a target ambient temperature between 44°C and 45°C.

Development and future of ultraviolet light-emitting diodes: UV-LED will replace the UV lamp

NASA Astrophysics Data System (ADS)

Muramoto, Yoshihiko; Kimura, Masahiro; Nouda, Suguru

2014-06-01

Ultraviolet light-emitting diodes (UV-LEDs) have started replacing UV lamps. The power per LED of high-power LED products has reached 12 W (14 A), which is 100 times the values observed ten years ago. In addition, the cost of these high-power LEDs has been decreasing. In this study, we attempt to understand the technologies and potential of UV-LEDs.

CALiPER Report 20.4: Lumen and Chromaticity Maintenance of LED PAR38 Lamps Operated in Steady-State Conditions

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

none,

2014-12-30

This CALiPER report focuses on lumen maintenance, chromaticity maintenance, and catastrophic failure in 32 of the Series 20 LED PAR38 lamps and 8 benchmark lamps, which were monitored for nearly 14,000 hours at ambient temperatures between 44°C and 45°C.

Impact assessment of energy-efficient lighting in patients with lupus erythematosus: a pilot study.

PubMed

Fenton, L; Dawe, R; Ibbotson, S; Ferguson, J; Silburn, S; Moseley, H

2014-03-01

Patients with lupus erythematosus (LE) are often abnormally photosensitive. Ultraviolet (UV) exposure can not only induce cutaneous lesions but may also contribute to systemic flares and disease progression. Various forms of energy-efficient lighting have been shown to emit UV radiation. To determine the effects of these emissions on individuals with LE. This assessment investigated cutaneous responses to repeated exposures from three types of lighting: compact fluorescent lamp (CFL), light-emitting diode (LED) and energy-efficient halogen (EEH). The subjects were 15 patients with LE and a control group of five healthy volunteers. No cutaneous LE lesions were induced by any of the light sources. Delayed skin erythema was induced at the site of CFL irradiation in six of the 15 patients with LE and two of the five healthy subjects. Erythema was increased in severity and more persistent in patients with LE. One patient with LE produced a positive delayed erythema to the EEH. A single patient with LE produced immediate abnormal erythemal responses to the CFL, LED and EEH. Further investigation revealed that this patient also had solar urticaria. All other subjects had negative responses to LED exposure. Compact fluorescent lamps emit UV that can induce skin erythema in both individuals with LE and healthy individuals when situated in close proximity. However, this occurs to a greater extent and is more persistent in patients with LE. EEHs emit UVA that can induce erythema in patients with LE. LEDs provide a safer alternative light source without risk of UV exposure. © 2013 British Association of Dermatologists.

A new phenomenon?

NASA Astrophysics Data System (ADS)

Ganci, S.

2017-03-01

This letter describes an interesting optical phenomenon engaging the reflected images of a new tube LED lamp (an array of high luminosity LEDs substituting the old fluorescent lamps) on any convex glossy black surface.

Demonstration of AC and DC charge control for the LISA test masses

NASA Astrophysics Data System (ADS)

Olatunde, Taiwo Janet

2018-01-01

Taiwo Olatunde, Stephen Apple, Andrew Chilton, Samantha Parry, Peter Wass, Guido Mueller, John W. Conklin The residual test mass acceleration in LISA must be below 3 fm/s2/√Hz at all frequencies between 0.1 and 3 mHz. Test mass charge coupled with stray electrical potentials and external electromagnetic fields is a well-known source of acceleration noise. LISA Pathfinder uses Hg lamps emitting mostly around 254 nm to discharge the test masses via photoemission, but a future LISA mission launched around 2030 will likely replace the lamps with newer UV LEDs with lower mass, better power efficiency, smaller size and higher bandwidth. This presentation will discuss charge control demonstrated on the torsion pendulum in AC and DC modes at the University of Florida using latest generation UV LEDs producing light at 240 nm with energy above the work function of pure Au. Initial results of Au quantum efficiency measurements (number of emitted electrons per incident photons) which is critical for bi-polar charge control will also be presented.

Alternatives to Outdoor Daylight Illumination for Photodynamic Therapy--Use of Greenhouses and Artificial Light Sources.

PubMed

Lerche, Catharina M; Heerfordt, Ida M; Heydenreich, Jakob; Wulf, Hans Christian

2016-02-29

Daylight-mediated photodynamic therapy (daylight PDT) is a simple and pain free treatment of actinic keratoses. Weather conditions may not always allow daylight PDT outdoors. We compared the spectrum of five different lamp candidates for indoor "daylight PDT" and investigated their ability to photobleach protoporphyrin IX (PpIX). Furthermore, we measured the amount of PpIX activating daylight available in a glass greenhouse, which can be an alternative when it is uncomfortable for patients to be outdoors. The lamps investigated were: halogen lamps (overhead and slide projector), white light-emitting diode (LED) lamp, red LED panel and lamps used for conventional PDT. Four of the five light sources were able to photobleach PpIX completely. For halogen light and the red LED lamp, 5000 lux could photobleach PpIX whereas 12,000 lux were needed for the white LED lamp. Furthermore, the greenhouse was suitable for daylight PDT since the effect of solar light is lowered only by 25%. In conclusion, we found four of the five light sources and the greenhouse usable for indoor daylight PDT. The greenhouse is beneficial when the weather outside is rainy or windy. Only insignificant ultraviolet B radiation (UVB) radiation passes through the greenhouse glass, so sun protection is not needed.

Alternatives to Outdoor Daylight Illumination for Photodynamic Therapy—Use of Greenhouses and Artificial Light Sources

PubMed Central

Lerche, Catharina M.; Heerfordt, Ida M.; Heydenreich, Jakob; Wulf, Hans Christian

2016-01-01

Daylight-mediated photodynamic therapy (daylight PDT) is a simple and pain free treatment of actinic keratoses. Weather conditions may not always allow daylight PDT outdoors. We compared the spectrum of five different lamp candidates for indoor “daylight PDT” and investigated their ability to photobleach protoporphyrin IX (PpIX). Furthermore, we measured the amount of PpIX activating daylight available in a glass greenhouse, which can be an alternative when it is uncomfortable for patients to be outdoors. The lamps investigated were: halogen lamps (overhead and slide projector), white light-emitting diode (LED) lamp, red LED panel and lamps used for conventional PDT. Four of the five light sources were able to photobleach PpIX completely. For halogen light and the red LED lamp, 5000 lux could photobleach PpIX whereas 12,000 lux were needed for the white LED lamp. Furthermore, the greenhouse was suitable for daylight PDT since the effect of solar light is lowered only by 25%. In conclusion, we found four of the five light sources and the greenhouse usable for indoor daylight PDT. The greenhouse is beneficial when the weather outside is rainy or windy. Only insignificant ultraviolet B radiation (UVB) radiation passes through the greenhouse glass, so sun protection is not needed. PMID:26938525

Retail Lamps Study 3.1: Dimming, Flicker, and Power Quality Characteristics of LED A Lamps

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

Royer, Michael P.; Poplawski, Michael E.; Brown, Charles C.

2014-12-01

To date, all three reports in the retail lamps series have focused on basic performance parameters, such as lumen output, efficacy, and color quality. This report goes a step further, examining the photoelectric characteristics (i.e., dimming and flicker) of a subset of lamps from CALiPER Retails Lamps Study 3. Specifically, this report focuses on the dimming, power quality, and flicker characteristics of 14 LED A lamps, as controlled by four different retail-available dimmers. The results demonstrate notable variation across the various lamps, but little variation between the four dimmers. Overall, the LED lamps: ~tended to have higher relative light outputmore » compared to the incandescent and halogen benchmark at the same dimmer output signal (RMS voltage). The lamps’ dimming curves (i.e., the relationship between control signal and relative light output) ranged from linear to very similar to the square-law curve typical of an incandescent lamp. ~generally exhibited symmetrical behavior—the same dimming curve—when measured proceeding from maximum to minimum or minimum to maximum control signal. ~mostly dimmed below 10% of full light output, with some exceptions for specific lamp and dimmer combinations ~exhibited a range of flicker characteristics, with many comparing favorably to the level typical of a magnetically-ballasted fluorescent lamp through at least a majority of the dimming range. ~ always exceeded the relative (normalized) efficacy over the dimming range of the benchmark lamps, which rapidly decline in efficacy when they are dimmed. This report generally does not attempt to rank the performance of one product compared to another, but instead focuses on the collective performance of the group versus conventional incandescent or halogen lamps, the performance of which is likely to be the baseline for a majority of consumers. Undoubtedly, some LED lamps perform better—or more similar to conventional lamps—than others. Some perform desirably for one characteristic, but not others. Consumers (and specifiers) may have a hard time distinguishing better-performing lamps from one another; at this time, physical experimentation is likely the best evaluation tool.« less

Evaluation of an LED (Light-Emitting Diode) high-mounted signal lamp

NASA Astrophysics Data System (ADS)

Olson, P. L.

1987-02-01

Two studies are described evaluating high-mounted stoplights using light-emitting diodes (LEDs) compared with conventional incandescent units. The first of these studies obtained ratings from subjects who drove one car and followed another car that was equipped with the test lamps. The results indicate that the subjects generally preferred the LEDs to the conventional lamp. The second study was a laboratory evaluation of the attention-getting capabilities of LED and incandescent stoplights. Under all conditions tested subjects responded faster to the LED units. The response time advantage for the LED units increased with more difficult viewing conditions, such as high levels of illumination and long viewing distance. The results of these investigations are discussed in terms of the applicability of the LED technology to high mounted stoplights on motor vehicles.

CALiPER Report 20.2: Dimming, Flicker, and Power Quality Characteristics of LED PAR38 Lamps

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

None, None

2014-03-31

This report focuses on the flicker and power quality performance of the Series 20 lamps at full output and various dimmed levels. All of the Series 20 PAR38 lamps that manufacturers claimed to be dimmable (including all halogen lamps) were evaluated individually (one lamp at a time) both on a switch and under the control of a phase-cut dimmer designed for use with "all classes of bulbs." Measurements of luminous flux, flicker, and power quality were taken at 10 target dimmed settings and compared with operation on a switch. Because only a single unit of each product was evaluated onmore » a single dimmer that may or may not have been recommended by its manufacturer, this report focuses on the performance of the products relative to each other, rather than the best-case performance of each lamp or variation in performance delivered from each lamp. Despite these limitations, the results suggest that LED performance is improving, and performance trends are beginning to emerge, perhaps due in part to the identification of preferred LED driver strategies for lamp products.« less

Investigation of uniformity field generated from freeform lens with UV LED exposure system

NASA Astrophysics Data System (ADS)

Ciou, F. Y.; Chen, Y. C.; Pan, C. T.; Lin, P. H.; Lin, P. H.; Hsu, F. T.

2015-03-01

In the exposure process, the intensity and uniformity of light in the exposure area directly influenced the precision of products. UV-LED (Ultraviolet Light-Emitting Diode) exposure system was established to reduce the radiation leakage and increase the energy efficiency for energy saving. It is a trend that conventional mercury lamp could be replaced with UV-LED exposure system. This study was based on the law of conservation of energy and law of refraction of optical field distributing on the target plane. With these, a freeform lens with uniform light field of main exposure area could be designed. The light outside the exposure area could be concentrated into the area to improve the intensity of light. The refraction index and UV transmittance of Polydimethylsiloxane (PDMS) is 1.43 at 385 nm wavelength and 85-90%, respectively. The PDMS was used to fabricate the optics lens for UV-LEDs. The average illumination and the uniformity could be obtained by increasing the number of UV-LEDs and the spacing of different arrangement modes. After exposure process with PDMS lens, about 5% inaccuracy was obtained. Comparing to 10% inaccuracy of general exposure system, it shows that it is available to replace conventional exposure lamp with using UV-LEDs.

Efficiency improvement of GaN-on-silicon thin-film light-emitting diodes with optimized via-like n-electrodes

NASA Astrophysics Data System (ADS)

Feng, Bo; Deng, Biao; Fu, Yi; Liu, Le Gong; Li, Zeng Cheng; Feng, Mei Xin; Zhao, Han Min; Sun, Qian

2017-07-01

This work reports a significant improvement in efficiency by optimizing the via-like n-electrode architecture design of a GaN-based thin-film LED grown on a 6-inch silicon substrate. The external quantum efficiency of the as-fabricated 1.1 mm × 1.1 mm via-thin-film LED chip at 350 mA was increased by 11.3% compared to that of a vertical thin-film LED chip with a conventional finger-like n-electrode. Detailed analysis of encapsulation gain and false color emission patterns illustrated that the significantly improved LED performance was due to enhanced light extraction efficiency and more uniform current spreading, both of which can be attributed to the optimized via-thin-film chip structure. Minimizing the light loss at the periphery of the Ag mirror was demonstrated to be a critical factor for improving light extraction, rather than simply replacing the finger-like n-electrodes with via-like ones. After encapsulation, the median blue lamp power and the wall-plug efficiency of the via-thin-film LED at 350 mA reached 659 mW and 63.7%, respectively.

Multiple transfer standard for calibration and characterization of test setups for LED lamps and luminaires in industry

NASA Astrophysics Data System (ADS)

Sperling, A.; Meyer, M.; Pendsa, S.; Jordan, W.; Revtova, E.; Poikonen, T.; Renoux, D.; Blattner, P.

2018-04-01

Proper characterization of test setups used in industry for testing and traceable measurement of lighting devices by the substitution method is an important task. According to new standards for testing LED lamps, luminaires and modules, uncertainty budgets are requested because in many cases the properties of the device under test differ from the transfer standard used, which may cause significant errors, for example if a LED-based lamp is tested or calibrated in an integrating sphere which was calibrated with a tungsten lamp. This paper introduces a multiple transfer standard, which was designed not only to transfer a single calibration value (e.g. luminous flux) but also to characterize test setups used for LED measurements with additional provided and calibrated output features to enable the application of the new standards.

An Investigation of Catastrophic Failure in Solid-State Lamps Exposed to Harsh Environment Operational Conditions

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

Lall, Pradeep; Sakalaukus, Peter; Davis, Lynn

2015-07-06

Today’s lighting technology is steadily becoming more energy efficient and less toxic to the environment since the passing of the Energy Independence and Security Act of 2007 (EISA) [1]. EISA has mandated a higher energy efficiency standard for lighting products and the phase out of the common incandescent lamp. This has led lighting manufacturers to pursue solid-state lighting (SSL) technologies for consumer lighting applications. However, two major roadblocks are hindering the transition process to SSL lamps: cost and quality. In order to cut cost, manufactures are moving towards cheaper packaging materials and a variety of package architecture construction techniques whichmore » may potentially erode the quality of the lamp and reduce its survivability in everyday applications. Typically, SSL lamps are given product lifetimes of over twenty years based off of the IES TM-21-11 lighting standard which does not include moisture effects or large operational temperatures [2]. A group of recently released off-the-shelf lamps have undergone a steady-state temperature humidity bias life test of 85°C/85%RH (85/85) to investigate the reliability in harsh environment applications. The lack of accelerated test methods for lamps to assess reliability prior to introduction into the marketplace does not exist in literature. There is a need for SSL physics based models for the assessment and prediction of a lamp’s lifetime which is being spearheaded by the DOE [3]. In order to be fully accepted in the marketplace, SSL lamps must be able to perform similarly to incandescent lamps in these environments, as well as live up to the lifetime claims of manufacturers. A lamp’s package architecture must be designed with performance factors in mind, as well as address some of the known and published package related failure mechanisms, such as carbonization of the encapsulant material, delamination, encapsulant yellowing, lens cracking, and phosphor thermal quenching [4]. Each failure mechanism produces the similar failure mode of lumen degradation predominately due to two contributing factors: high junction temperature and moisture ingress. The current state-of-the-art has focused on individual areas of the lamp, such as the LED chip, substrate material, electrical driver design and thermal management techniques. [5] – [16] Looking at the lamp as a whole is a novel approach and has not been seen before in literature. This work followed the JEDEC standard JESD22-A101C of 85/85 with a one hour interval of applied voltage followed by a one hour interval of no applied voltage [17]. This test was performed continuously for each SSL lamp until it became nonoperational, i.e. did not turn on. Periodically, photometric measurements were taken following the IES LM-79-08 standard at room temperature using an integrating sphere, a spectrometer, and lighting software. The overall health of the SSL lamps was assed using the relative luminous flux (RLF), correlated color temperature (CCT) and the color difference (Δu'v') using the Euclidean distance of the CIE 1976 color space coordinates. Finally, a Weibull analysis was completed to compare the characteristic lifetime of the SSL lamp to the actual rated lifetime. An important result from this work shows that the rated lifetime does not come close to the actual lifetime when the SSL lamps are used in a harsh humid environment which is fairly common in outdoor applications across the U.S. Also, the photometric results are presented for the entire lifetime of each SSL lamp under test.« less

Light Sources and Lighting Circuits

NASA Astrophysics Data System (ADS)

Honda, Hisashi; Suwa, Takumi; Yasuda, Takeo; Ohtani, Yoshihiko; Maehara, Akiyoshi; Okada, Atsunori; Komatsu, Naoki; Mannami, Tomoaki

According to the Machinery Statistics of the Ministry of Economy, Trade and Industry, the production of incandescent lamps in Japan in 2007 was 990 million units (90.0% of the previous year's total), in which the production of incandescent lamps for general lighting was 110 million units (90.0% of the previous year's total) and of tungsten-halogen lamps was 44 million units (96.6% of the previous year's total). The production of fluorescent lamps was 927 million units (93.9% of the previous year's total), in which general fluorescent lamps, excluding those for LCD back lighting, was 320 million units (87.2% of the previous year's total). Also, the production of HID lamps was 10 million units (101.5% of the previous year's total). On the other hand, when the numbers of sales are compared with the sales of the previous year, incandescent lamps for general use was 99.8%, tungsten-halogen lamps was 96.9%, fluorescent lamps was 95.9%, and HID lamps was 98.9%. Self-ballasted fluorescent lamps alone showed an increase in sales as strong as 29 million units, or 121.7% of the previous year's sales. It is considered that the switchover of incandescent lamps to HID lamps was promoted for energy conservation and carbon dioxide reduction with the problem of global warming in the background. In regard to exhibitions, Lighting Fair 2007 was held in Tokyo in March, and LIGHTFAIR INTERNATIONAL 2007 was held in New York in May. Regarding academic conferences, LS:11 (the 11th International Symposium on the Science & Technology of Light Sources) was held in Shanghai in May, and the First International Conference on White LEDs and Solid State Lighting was held in Tokyo in November. Both conferences suggested that there are strong needs and concerns now about energy conservation, saving natural resources, and restrictions of hazardous materials. In regard to incandescent lamps, the development of products aiming at higher efficacy, electric power savings, and longer life was advanced by means of using filler gas with a higher atomic weight. Regarding fluorescent lamps, studies and developments for longer operating life and improvement in the lumen maintenance factor for the straight-type and circular-type fluorescent lamps were actively pursued. Regarding self-ballasted fluorescent lamps, the main stream of development was aimed at reducing lamp size and increasing energy conservation, and the development of new products that took advantage of these features proceeded. In regard to LED light sources, basic research and product development, including new application development, were vigorously implemented. In basic research, studies were reported, not only on efficacy improvements through optimization of the LED chips, phosphor layers, and packaging technology, but also on photometry, colorimetry, and visual psychology. In the field of application, applications were studied for general lighting sources and also for a wide range of fields, such as automotive headlights and visible light communication. Also, many academic conferences and exhibitions were held domestically and overseas, and the high level of interest suggests high expectations for this next-generation light source. Regarding HID lamps, there was much activity in research and development and in the commercialization of the ceramic metal halide lamp product, and products were commercialized with features such as higher efficiency (130 lm/W) and higher color rendering properties (R9 ≥ 90). In the high-pressure sodium lamps, there were many study reports concerning plant growth and insect pest control using its low insect-attracting characteristics. With high-pressure mercury lamps, there were many reports on reducing lamp size and increasing intensity for use as a light source for projectors.

Lamp of adjustable spectrum for photographic usage

NASA Astrophysics Data System (ADS)

Mazikowski, Adam; Feldzensztajn, Mateusz

2017-08-01

Photography is a unique rapidly growing interdisciplinary field encompassing aspects of science, art and technology. Expectations of photographers are steadily increasing with the development of technology. One of the areas playing a crucial role in photography is lighting. Consequently, several types of light sources for photographic use have been developed. The ongoing research in this field concentrates on lamps with tunable CCT (Correlated Color Temperature). In this paper, we present a lamp, which emission spectrum can be tailored without affecting the output luminous ux. Intended for photographic uses, the lamp is based on an integrating sphere and a selection of LEDs. As the LED drivers, DC-DC converters controlled by a Raspberry PI were applied. Design process, including the selection of LED wavelengths, is presented. Output characteristics of the lamp were measured using the setup containing the spectrometer. The results of these experiments show good agreement with the spectrum set on the microcomputer.

SSL Pricing and Efficacy Trend Analysis for Utility Program Planning

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

Tuenge, Jason R.

2013-10-01

An LED lamp or luminaire can generally be found that matches or exceeds the efficacy of benchmark technologies in a given product category, and LED products continue to expand into ever-higher lumen output niches. However, the price premium for LED continues to pose a barrier to adoption in many applications, in spite of expected savings from reduced energy use and maintenance. Other factors—such as dimmability and quality of light—can also present challenges. The appropriate type, timing, and magnitude of energy efficiency activities will vary from organization to organization based on local variables and the method of evaluation. A number ofmore » factors merit consideration when prioritizing activities for development. Category-specific projections for pricing and efficacy are provided herein to assist in efficiency program planning efforts.« less

Controllable light beam shaper in LED lamp

NASA Astrophysics Data System (ADS)

Nessemon, K. D.; Popov, I. V.; Belyaev, V. V.; Belyaev, A. A.; Velichko, V. K.

2018-03-01

A design of an LED lamp with controllable shape and intensity of the light beam formed is described. The effect is achieved by dividing the light irradiating area for four section and their special fixation and fastening.

A novel solution for LED wall lamp design and simulation

NASA Astrophysics Data System (ADS)

Ge, Rui; Hong, Weibin; Li, Kuangqi; Liang, Pengxiang; Zhao, Fuli

2014-11-01

The model of the wall washer lamp and the practical illumination application have been established with a new design of the lens to meet the uniform illumination demand for wall washer lamp based on the Lambertian light sources. Our secondary optical design of freeform surface lens to LED wall washer lamp based on the conservation law of energy and Snell's law can improve the lighting effects as a uniform illumination. With the relationship between the surface of the lens and the surface of the target, a great number of discrete points of the freeform profile curve were obtained through the iterative method. After importing the data into our modeling program, the optical entity was obtained. Finally, to verify the feasibility of the algorithm, the model was simulated by specialized software, with both the LED Lambertian point source and LED panel source model.

Minimization of lumen depreciation in LED lamps using thermal transient behavior analysis and design optimizations.

PubMed

Khan, M Nisa

2016-02-10

We expansively investigate thermal behaviors of various general-purpose light-emitting diode (LED) lamps and apply our measured results, validated by simulation, to establish lamp design rules for optimizing their optical and thermal properties. These design rules provide the means to minimize lumen depreciation over time by minimizing the periods for lamps to reach thermal steady-state while maintaining their high luminous efficacy and omnidirectional light distribution capability. While it is well known that minimizing the junction temperature of an LED leads to a longer lifetime and an increased lumen output, our study demonstrates, for the first time, to the best of our knowledge, that it is also important to minimize the time it takes to reach thermal equilibrium because doing so minimizes lumen depreciation and enhances light output and color stability during operation. Specifically, we have found that, in addition to inadequate heat-sink fin areas for a lamp configuration, LEDs mounted on multiple boards, as opposed to a single board, lead to longer periods for reaching thermal equilibrium contributing to larger lumen depreciation.

UV-LED-based charge control for LISA

NASA Astrophysics Data System (ADS)

Olatunde, Taiwo; Shelley, Ryan; Chilton, Andrew; Ciani, Giacomo; Mueller, Guido; Conklin, John

2014-03-01

The test masses inside the LISA gravitational reference sensors (GRS) must maintain almost pure geodesic motion for gravitational waves to be successfully detected. The residual accelerations have to stay below 3fm/s2/rtHz at all frequencies between 0.1 and 3 mHz. One of the well known noise sources is associated with the charges on the test masses which couple to stray electrical potentials and external electro-magnetic fields. The LISA pathfinder (LPF) will use Hg-discharge lamps emitting mostly around 253 nm to discharge the test masses via photoemission in its 2015/16 flight. A future LISA mission launched around 2030 will likely replace the lamps with newer UV-LEDs. UV-LEDs have a lower mass, a better power efficiency, and are smaller than their Hg counterparts. Furthermore, the latest generation produces light at 240 nm, with energy well above the work function of pure gold. I will describe a preliminary design for effective charge control through photoelectric effect by using these LEDs. The effectiveness of this method is verified by taking Quantum Efficiency (QE) measurements which relate the number of electrons emitted to the number of photons incident on the Au test mass surface. This presentation addresses our initial results and future plans which includes implementation and testing in the UF torsion pendulum and space-qualification in a small satellite mission which will launch in the summer of 2014, through a collaboration with Stanford, KACST, and NASA Ames Research Center.

Potency of energy saving and emission reduction from lighting system in residential sector of Indonesia

NASA Astrophysics Data System (ADS)

Ambarita, H.

2018-03-01

The Government of Indonesia (GoI) has a strong commitment to the target of decreasing energy intensity and reducing Greenhouse gas emissions. One of the significant solutions to reach the target is increasing energy efficiency in the lighting system in the residential sector. The objective of this paper is twofold, to estimate the potency of energy saving and emission reduction from lighting in the residential sector. Literature related to the lighting system in Indonesia has been reviewed to provide sufficient data for the estimation of the energy saving and emission reduction. The results show that the in the year 2016, a total of 95.33 TWh of nationally produced electricity is used in the residential sector. This is equal to 44% of total produced electricity. The number of costumers is 64.78 million houses. The average number of lamps and average wattage of lamps used in Indonesia are 8.35 points and 13.8 W, respectively. The number of lighting and percentage of electricity used for lighting in the residential sector in Indonesia are 20.03 TWh (21.02 %) and 497 million lamps, respectively. The projection shows that in the year 2026 the total energy for lighting and number of lamps in the residential sector are 25.05 TWh and 619 million, respectively. By promoting the present technology of high efficient lamps (LED), the potency of energy saving and emission reduction in 2026 are 2.6 TWh and 2.1 million tons CO2eq, respectively.

Photovoltaic powered ultraviolet and visible light-emitting diodes for sustainable point-of-use disinfection of drinking waters.

PubMed

Lui, Gough Yumu; Roser, David; Corkish, Richard; Ashbolt, Nicholas; Jagals, Paul; Stuetz, Richard

2014-09-15

For many decades, populations in rural and remote developing regions will be unable to access centralised piped potable water supplies, and indeed, decentralised options may be more sustainable. Accordingly, improved household point-of-use (POU) disinfection technologies are urgently needed. Compared to alternatives, ultraviolet (UV) light disinfection is very attractive because of its efficacy against all pathogen groups and minimal operational consumables. Though mercury arc lamp technology is very efficient, it requires frequent lamp replacement, involves a toxic heavy metal, and their quartz envelopes and sleeves are expensive, fragile and require regular cleaning. An emerging alternative is semiconductor-based units where UV light emitting diodes (UV-LEDs) are powered by photovoltaics (PV). Our review charts the development of these two technologies, their current status, and challenges to their integration and POU application. It explores the themes of UV-C-LEDs, non-UV-C LED technology (e.g. UV-A, visible light, Advanced Oxidation), PV power supplies, PV/LED integration and POU suitability. While UV-C LED technology should mature in the next 10 years, research is also needed to address other unresolved barriers to in situ application as well as emerging research opportunities especially UV-A, photocatalyst/photosensitiser use and pulsed emission options. Copyright © 2014 Elsevier B.V. All rights reserved.

Phototaxis of Propsilocerus akamusi (Diptera: Chironomidae) From a Shallow Eutrophic Lake in Response to Led Lamps.

PubMed

Hirabayashi, Kimio; Nagai, Yoshinari; Mushya, Tetsuya; Higashino, Makoto; Taniguchi, Yoshio

2017-06-01

A study on the attraction of adult Propsilocerus akamusi midges to different-colored light traps was carried out from October 21 to November 15, 2013. The 6 colored lights used in light-emitting diode (LED) lamps were white, green, red, blue, amber, and ultraviolet (UV). The UV lamp attracted the most P. akamusi, followed by green, white, blue, amber, and red. A white pulsed LED light attracted only half the number of midges as did a continuous-emission white LED light. The result indicated that manipulation of light color, considering that the red LED light and/or pulsed LED light are not as attractive as the other colors, may be appropriate for the development of an overall integrated strategy to control nuisance P. akamusi in the Lake Suwa area.

Light-emitting diodes as a radiation source for plants

NASA Technical Reports Server (NTRS)

Bula, R. J.; Morrow, R. C.; Tibbitts, T. W.; Barta, D. J.; Ignatius, R. W.; Martin, T. S.

1991-01-01

Development of a more effective radiation source for use in plant-growing facilities would be of significant benefit for both research and commercial crop production applications. An array of light-emitting diodes (LEDs) that produce red radiation, supplemented with a photosynthetic photon flux (PPF) of 30 micromoles s-1 m-2 in the 400- to 500-nm spectral range from blue fluorescent lamps, was used effectively as a radiation source for growing plants. Growth of lettuce (Lactuca sativa L. Grand Rapids') plants maintained under the LED irradiation system at a total PPF of 325 micromoles s-1 m-2 for 21 days was equivalent to that reported in the literature for plants grown for the same time under cool-white fluorescent and incandescent radiation sources. Characteristics of the plants, such as leaf shape, color, and texture, were not different from those found with plants grown under cool-white fluorescent lamps. Estimations of the electrical energy conversion efficiency of a LED system for plant irradiation suggest that it may be as much as twice that published for fluorescent systems.

The health risks associated with energy efficient fluorescent, LEDs, and artificial lighting

NASA Astrophysics Data System (ADS)

Panahi, Allen

2014-09-01

With the phasing out of incandescent lamps in many countries, the introduction of new LED based light sources and luminaries sometimes raise the question of whether the spectral characteristics of the LED and other energy savings Fluorescent lights including the popular CFLs are suitable to replace the traditional incandescent lamps. These concerns are sometimes raised particularly for radiation emissions in the UV and Blue parts of the spectrum. This paper aims to address such concerns for the common `white light' sources typically used in household and other general lighting used in the work place. Recent studies have shown that women working the night shift have an increased probability of developing breast cancer. We like to report on the findings of many studies done by medical professionals, in particular the recent announcement of AMA in the US and many studies conducted in the UK, as well as the European community to increase public awareness on the long term health risks of the optical and opto-biological effects on the human health caused by artificial lighting.

Significant growth in. LED use predicted.

PubMed

Simpson, Mike

2012-03-01

Although LED lighting has its critics, a number of whom (see article 'LED--panacea or marketing hype', HEJ--February 2012) are concerned about what they claim are some manufacturers' 'exaggerated claims' about lighting efficiency and lamp lifetime, Philips Lighting believes that, such are the advances being made in this innovative lighting technology, that LED's overall share of the European lighting market will have risen from around 7% in 2008 to 25% by 2020 and that, a decade later, it will account for a remarkable 75% of lighting sales. In the UK, Philips' technical and design director for Lighting, Mike Simpson, told HEJ editor, Jonathan Baillie, healthcare estates and facilities managers are increasingly recognising the potential to save energy, reduce carbon emissions, and cut maintenance costs, using LED.

Comparison of direct and alternating current vacuum ultraviolet lamps in atmospheric pressure photoionization.

PubMed

Vaikkinen, Anu; Haapala, Markus; Kersten, Hendrik; Benter, Thorsten; Kostiainen, Risto; Kauppila, Tiina J

2012-02-07

A direct current induced vacuum ultraviolet (dc-VUV) krypton discharge lamp and an alternating current, radio frequency (rf) induced VUV lamp that are essentially similar to lamps in commercial atmospheric pressure photoionization (APPI) ion sources were compared. The emission distributions along the diameter of the lamp exit window were measured, and they showed that the beam of the rf lamp is much wider than that of the dc lamp. Thus, the rf lamp has larger efficient ionization area, and it also emits more photons than the dc lamp. The ionization efficiencies of the lamps were compared using identical spray geometries with both lamps in microchip APPI mass spectrometry (μAPPI-MS) and desorption atmospheric pressure photoionization-mass spectrometry (DAPPI-MS). A comprehensive view on the ionization was gained by studying six different μAPPI solvent compositions, five DAPPI spray solvents, and completely solvent-free DAPPI. The observed reactant ions for each solvent composition were very similar with both lamps except for toluene, which showed a higher amount of solvent originating oxidation products with the rf lamp than with the dc lamp in μAPPI. Moreover, the same analyte ions were detected with both lamps, and thus, the ionization mechanisms with both lamps are similar. The rf lamp showed a higher ionization efficiency than the dc lamp in all experiments. The difference between the lamp ionization efficiencies was greatest when high ionization energy (IE) solvent compositions (IEs above 10 eV), i.e., hexane, methanol, and methanol/water, (1:1 v:v) were used. The higher ionization efficiency of the rf lamp is likely due to the larger area of high intensity light emission, and the resulting larger efficient ionization area and higher amount of photons emitted. These result in higher solvent reactant ion production, which in turn enables more efficient analyte ion production. © 2012 American Chemical Society

Progress in extremely high brightness LED-based light sources

NASA Astrophysics Data System (ADS)

Hoelen, Christoph; Antonis, Piet; de Boer, Dick; Koole, Rolf; Kadijk, Simon; Li, Yun; Vanbroekhoven, Vincent; Van De Voorde, Patrick

2017-09-01

Although the maximum brightness of LEDs has been increasing continuously during the past decade, their luminance is still far from what is required for multiple applications that still rely on the high brightness of discharge lamps. In particular for high brightness applications with limited étendue, e.g. front projection, only very modest luminance values in the beam can be achieved with LEDs compared to systems based on discharge lamps or lasers. With dedicated architectures, phosphor-converted green LEDs for projection may achieve luminance values up to 200-300 Mnit. In this paper we report on the progress made in the development of light engines based on an elongated luminescent concentrator pumped by blue LEDs. This concept has recently been introduced to the market as ColorSpark High Lumen Density LED technology. These sources outperform the maximum brightness of LEDs by multiple factors. In LED front projection, green LEDs are the main limiting factor. With our green modules, we now have achieved peak luminance values of 2 Gnit, enabling LED-based projection systems with over 4000 ANSI lm. Extension of this concept to yellow and red light sources is presented. The light source efficiency has been increased considerably, reaching 45-60 lm/W for green under practical application conditions. The module architecture, beam shaping, and performance characteristics are reviewed, as well as system aspects. The performance increase, spectral range extensions, beam-shaping flexibility, and cost reductions realized with the new module architecture enable a breakthrough in LED-based projection systems and in a wide variety of other high brightness applications.

Using UVC Light-Emitting Diodes at Wavelengths of 266 to 279 Nanometers To Inactivate Foodborne Pathogens and Pasteurize Sliced Cheese

PubMed Central

Kim, Soo-Ji; Kim, Do-Kyun

2015-01-01

UVC light is a widely used sterilization technology. However, UV lamps have several limitations, including low activity at refrigeration temperatures, a long warm-up time, and risk of mercury exposure. UV-type lamps only emit light at 254 nm, so as an alternative, UV light-emitting diodes (UV-LEDs) which can produce the desired wavelengths have been developed. In this study, we validated the inactivation efficacy of UV-LEDs by wavelength and compared the results to those of conventional UV lamps. Selective media inoculated with Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes were irradiated using UV-LEDs at 266, 270, 275, and 279 nm in the UVC spectrum at 0.1, 0.2, 0.5, and 0.7 mJ/cm2, respectively. The radiation intensity of the UV-LEDs was about 4 μW/cm2, and UV lamps were covered with polypropylene films to adjust the light intensity similar to those of UV-LEDs. In addition, we applied UV-LED to sliced cheese at doses of 1, 2, and 3 mJ/cm2. Our results showed that inactivation rates after UV-LED treatment were significantly different (P < 0.05) from those of UV lamps at a similar intensity. On microbiological media, UV-LED treatments at 266 and 270 nm showed significantly different (P < 0.05) inactivation effects than other wavelength modules. For sliced cheeses, 4- to 5-log reductions occurred after treatment at 3 mJ/cm2 for all three pathogens, with negligible generation of injured cells. PMID:26386061

The photocytotoxicity of different lights on mammalian cells in interior lighting system.

PubMed

Song, Jiayin; Gao, Tingting; Ye, Maole; Bi, Hongtao; Liu, Gang

2012-12-05

In the present paper, two light sources commonly used in interior lighting system: incandescent light and light emitting diode (LED) were chosen to evaluate their influences on three kinds of mammalian cells, together with UVA and UVB, and the mechanism of the photocytotoxicity was investigated in terms of intracellular ROS production, lipid peroxidation, SOD activity and GSH level assays. The results showed that LED and incandescent light both had some photocytotoxicities. In the interior lighting condition (100lx-250lx), the cytotoxicities of LED and incandescent lamp on RF/6A cells (rhesus retinal pigment epithelium cell line) were stronger than that on two fibroblast cell lines, while the cytotoxicity of UVA and UVB on HS68 cells (fibroblast cell line) was highest in the tests. The mechanism analysis revealed that the photocytotoxicities of LED and incandescent lamp were both caused by cell lipid peroxidation. LED and incandescent light could promote the production of ROS, raise lipid peroxidation level and lower the activity of the antioxidant key enzymes in mammalian cells, and finally cause a number of cells death. However, the negative function of LED was significantly smaller than incandescent light and ultraviolet in daily interior lighting condition. And the significantly lower photocytotoxicity of LED might be due to the less existence of ultraviolet. Therefore, LED is an efficient and relative safe light source in interior lighting system, which should be widely used instead of traditional light source. Copyright © 2012 Elsevier B.V. All rights reserved.

Comparison of loop-mediated isothermal amplification assay and smear microscopy with culture for the diagnostic accuracy of tuberculosis.

PubMed

Gelaw, Baye; Shiferaw, Yitayal; Alemayehu, Marta; Bashaw, Abate Assefa

2017-01-17

Tuberculosis (TB) caused by Mycobacterium tuberculosis is one of the leading causes of death from infectious diseases worldwide. Sputum smear microscopy remains the most widely available pulmonary TB diagnostic tool particularly in resource limited settings. A highly sensitive diagnostic with minimal infrastructure, cost and training is required. Hence, we assessed the diagnostic performance of Loop-mediated isothermal amplification (LAMP) assay in detecting M.tuberculosis infection in sputum sample compared to LED fluorescent smear microscopy and culture. A cross-sectional study was conducted at the University of Gondar Hospital from June 01, 2015 to August 30, 2015. Pulmonary TB diagnosis using sputum LED fluorescence smear microscopy, TB-LAMP assay and culture were done. A descriptive analysis was used to determine demographic characteristics of the study participants. Analysis of sensitivity and specificity for smear microscopy and TB-LAMP compared with culture as a reference test was performed. Cohen's kappa was calculated as a measure of agreement between the tests. A total of 78 pulmonary presumptive TB patients sputum sample were analyzed. The overall sensitivity and specificity of LAMP were 75 and 98%, respectively. Among smear negative sputum samples, 33.3% sensitivity and 100% specificity of LAMP were observed. Smear microscopy showed 78.6% sensitivity and 98% specificity. LAMP and smear in series had sensitivity of 67.8% and specificity of 100%. LAMP and smear in parallel had sensitivity of 85.7% and specificity of 96%. The agreement between LAMP and fluorescent smear microscopy tests was very good (κ = 0.83, P-value ≤0.0001). TB-LAMP showed similar specificity but a slightly lower sensitivity with LED fluorescence microscopy. The specificity of LAMP and smear microscopy in series was high. The sensitivity of LAMP was insufficient for smear negative sputum samples.

Design method of LED rear fog lamp based on freeform micro-surface reflectors

NASA Astrophysics Data System (ADS)

Yu, Jindong; Wu, Heng

2017-11-01

We propose a practical method for the design of a light-emitting diode (LED) rear fog lamp based on freeform micro-surface reflectors. The lamp consists of nine LEDs and each of them has a freeform micro-surface reflector correspondingly. The micro-surface reflector design includes three steps. An initial freeform reflector is first built based on the light energy maps. The micro-surface reflector is then constructed on the bias of the initial one. Finally, a two-step method is designed to optimize the micro-surface reflector. With the proposed method, a module is designed and LCW DURIS E5 LED source whose emitting surface is 5.7 mm × 3.0 mm is adopted for simulation. A prototype is also assembled and fabricated to verify the real performance. Both the simulation and experimental results demonstrate that the luminous intensity distribution can well fulfill the requirements of ECE No.38 regulation. Furthermore, more than 79% energy can be saved when compared with the rear fog lamps using conventional sources.

Using UVC Light-Emitting Diodes at Wavelengths of 266 to 279 Nanometers To Inactivate Foodborne Pathogens and Pasteurize Sliced Cheese.

PubMed

Kim, Soo-Ji; Kim, Do-Kyun; Kang, Dong-Hyun

2016-01-01

UVC light is a widely used sterilization technology. However, UV lamps have several limitations, including low activity at refrigeration temperatures, a long warm-up time, and risk of mercury exposure. UV-type lamps only emit light at 254 nm, so as an alternative, UV light-emitting diodes (UV-LEDs) which can produce the desired wavelengths have been developed. In this study, we validated the inactivation efficacy of UV-LEDs by wavelength and compared the results to those of conventional UV lamps. Selective media inoculated with Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes were irradiated using UV-LEDs at 266, 270, 275, and 279 nm in the UVC spectrum at 0.1, 0.2, 0.5, and 0.7 mJ/cm(2), respectively. The radiation intensity of the UV-LEDs was about 4 μW/cm(2), and UV lamps were covered with polypropylene films to adjust the light intensity similar to those of UV-LEDs. In addition, we applied UV-LED to sliced cheese at doses of 1, 2, and 3 mJ/cm(2). Our results showed that inactivation rates after UV-LED treatment were significantly different (P < 0.05) from those of UV lamps at a similar intensity. On microbiological media, UV-LED treatments at 266 and 270 nm showed significantly different (P < 0.05) inactivation effects than other wavelength modules. For sliced cheeses, 4- to 5-log reductions occurred after treatment at 3 mJ/cm(2) for all three pathogens, with negligible generation of injured cells. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

A LED-based method for monitoring NAD(P)H and FAD fluorescence in cell cultures and brain slices.

PubMed

Rösner, Jörg; Liotta, Agustin; Schmitz, Dietmar; Heinemann, Uwe; Kovács, Richard

2013-01-30

Nicotinamide- and flavine-adenine-dinucleotides (NAD(P)H and FADH₂) are electron carriers involved in cellular energy metabolism and in a multitude of enzymatic processes. As reduced NAD(P)H and oxidised FAD molecules are fluorescent, changes in tissue auto-fluorescence provide valuable information on the cellular redox state and energy metabolism. Since fluorescence excitation, by mercury arc lamps (HBO) is inherently coupled to photo-bleaching and photo-toxicity, microfluorimetric monitoring of energy metabolism might benefit from the replacement of HBO lamps by light emitting diodes (LEDs). Here we describe a LED-based custom-built setup for monitoring NAD(P)H and FAD fluorescence at the level of single cells (HEK293) and of brain slices. We compared NAD(P)H bleaching characteristics with two light sources (HBO lamp and LED) as well as sensitivity and signal to noise ratio of three different detector types (multi-pixel photon counter (MPPC), photomultiplier tube (PMT) and photodiode). LED excitation resulted in reduced photo-bleaching at the same fluorescence output in comparison to excitation with the HBO lamp. Transiently increasing LED power resulted in reversible bleaching of NAD(P)H fluorescence. Recovery kinetics were dependent on metabolic substrates indicating coupling of NAD(P)H fluorescence to metabolism. Electrical stimulation of brain slices induced biphasic redox changes, as indicated by NAD(P)H/FAD fluorescence transients. Increasing the gain of PMT and decreasing the LED power resulted in similar sensitivity as obtained with the MPPC and the photodiode, without worsening the signal to noise ratio. In conclusion, replacement of HBO lamp with LED might improve conventional PMT based microfluorimetry of tissue auto-fluorescence. Copyright © 2012 Elsevier B.V. All rights reserved.

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

Gordon, Kelly L.; Foster, Rebecca; McGowan, Terry

This article for a building trade magazine describes a national design competition for energy efficient lighting sponsored by the U.S. Department of Energy, the American Lighting Association, and the Consortium for Energy Efficiency, with winners announced at ALA's Annual Conference May 14, 2004, in Tucson. The Lighting for Tomorrow competition was the first national lighting fixture design competition focusing on energy-efficient residential lighting. The competition invited fixture manufacturers and designers to come up with beautiful, functional lighting fixtures that also happen to be energy efficient. Fixtures were required to use a ''dedicated'' energy-efficient light source, such as a pin-based fluorescentmore » lamp that cannot be replaced with a screw-in incandescent bulb. Fixtures also had to meet a minimum energy efficiency level that eliminated use of incandescent and halogen lamps, leaving the door open only to fluorescent sources and LEDs. More than 150 paper designs were submitted in the first phase of the competition, in 2003. Of those, 24 finalists were invited to submit working prototypes in 2004, and the winners were announced in May. The Grand Prize of $10,000 went to American Fluorescent of Waukegan, Illinois, for its ''Salem'' chandelier. Some winning fixtures are already available through Lowe's Home Improvement Centers.« less

Demonstration Assessment of Light Emitting Diode (LED) Commercial Garage Lights In the Providence Portland Medical Center, Portland, Oregon

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

Ton, My K.; Richman, Eric E.; Gilbride, Theresa L.

2008-11-11

This U.S. Department of Energy GATEWAY Demonstration project studied the applicability of light-emitting diode (LED) luminaires for commercial parking garage applications. High-pressure sodium (HPS) area luminaires were replaced with new LED area luminaires. The project was supported under the U.S. Department of Energy (DOE) Solid State Lighting Program. Other participants in the demonstration project included Providence Portland Medical Center in Portland, Oregon, the Energy Trust of Oregon, and Lighting Sciences Group (LSG) Inc. Pacific Northwest National Laboratory (PNNL) conducted the measurements and analysis of the results. PNNL manages GATEWAY demonstrations for DOE and represents their perspective in the conduct ofmore » the work. Quantitative and qualitative measurements of light and electrical power were taken at the site for both HPS and LED light sources. Economic costs were estimated and garage users’ responses to the new light sources were gauged with a survey. Six LED luminaires were installed in the below-ground parking level A, replacing six existing 150W HPS lamps spread out over two rows of parking spaces. Illuminance measurements were taken at floor level approximately every 4 ft on a 60-ft x 40-ft grid to measure light output of these LED luminaires which were termed the “Version 1” luminaires. PNNL conducted power measurements of the circuit in the garage to which the 6 luminaires were connected and determined that they drew an average of 82 W per lamp. An improved LED luminaire, Version 2, was installed in Level B of the parking garage. Illuminance measurements were not made of this second luminaire on site due to higher traffic conditions, but photometric measurements of this lamp and Version 1 were made in an independent testing laboratory and power usage for Version 2 was also measured. Version 1 was found to produce 3600 lumens and Version 2 was found to produce 4700 lumens of light and to consume 78 Watts. Maximum and minimum light levels were measured for the HPS and LED Version 1 luminaires and projected for the Version 2 luminaires. Maximum light levels were 23.51 foot candles, 20.54 fc, and 26.7 fc respectively and minimum light levels were 1.49 fc, 1.45 fc, and 1.88 fc. These results indicate very similar or even slightly higher light levels produced by the LED lamps, despite the higher lumen output of the HPS lamp. The LED lamps provide higher luminaire efficacy because all of the light is directed down and out. None of it is “lost” in the fixture. Also the HPS luminaire had poorly designed optics and a plastic covering that tended to get dirty and cracked, further decreasing the realized light output.[is this an accurate way to say this?] Consumer perceptions of the Version 2 LED were collected via a written survey form given to maintenance and security personnel. More than half felt the LED luminaires provided more light than the HPS lamps and a majority expressed a preference for the new lamps when viewing the relamped area through a security camera. Respondents commented that the LED luminaires were less glary, created less shadows, had a positive impact on visibility, and improved the overall appearance of the area. PNNL conducted an economic analysis and found that the Version 1 lamp produced annual energy savings of 955 kWh and energy cost savings of $76.39 per lamp at electricity rates of 6.5 cents per kWh and $105.03 at 11 cents per kWh. PNNL found that the Version 2 lamp produced annual energy savings of 991 kWh and energy cost savings of $79.26 per lamp at electricity rates of 6.5 cents per kWh and $108.98 at 11 cents per kWh. PNNL also calculated simple payback and found that Version 1 showed paybacks of 5.4 yrs at 6.5c/kWh and 4.1 yrs at 11c/kWh while Version 2 showed paybacks of 5.2 yrs at 6.5c/kWh and 3.9 yrs at 11c/kWh.« less

Protocol for Determining Ultraviolet Light Emitting Diode (UV-LED) Fluence for Microbial Inactivation Studies.

PubMed

Kheyrandish, Ataollah; Mohseni, Madjid; Taghipour, Fariborz

2018-06-15

Determining fluence is essential to derive the inactivation kinetics of microorganisms and to design ultraviolet (UV) reactors for water disinfection. UV light emitting diodes (UV-LEDs) are emerging UV sources with various advantages compared to conventional UV lamps. Unlike conventional mercury lamps, no standard method is available to determine the average fluence of the UV-LEDs, and conventional methods used to determine the fluence for UV mercury lamps are not applicable to UV-LEDs due to the relatively low power output, polychromatic wavelength, and specific radiation profile of UV-LEDs. In this study, a method was developed to determine the average fluence inside a water suspension in a UV-LED experimental setup. In this method, the average fluence was estimated by measuring the irradiance at a few points for a collimated and uniform radiation on a Petri dish surface. New correction parameters were defined and proposed, and several of the existing parameters for determining the fluence of the UV mercury lamp apparatus were revised to measure and quantify the collimation and uniformity of the radiation. To study the effect of polychromatic output and radiation profile of the UV-LEDs, two UV-LEDs with peak wavelengths of 262 and 275 nm and different radiation profiles were selected as the representatives of typical UV-LEDs applied to microbial inactivation. The proper setup configuration for microorganism inactivation studies was also determined based on the defined correction factors.

Technology for radiation efficiency measurement of high-power halogen tungsten lamp used in calibration of high-energy laser energy meter.

PubMed

Wei, Ji Feng; Hu, Xiao Yang; Sun, Li Qun; Zhang, Kai; Chang, Yan

2015-03-20

The calibration method using a high-power halogen tungsten lamp as a calibration source has many advantages such as strong equivalence and high power, so it is very fit for the calibration of high-energy laser energy meters. However, high-power halogen tungsten lamps after power-off still reserve much residual energy and continually radiate energy, which is difficult to be measured. Two measuring systems were found to solve the problems. One system is composed of an integrating sphere and two optical spectrometers, which can accurately characterize the radiative spectra and power-time variation of the halogen tungsten lamp. This measuring system was then calibrated using a normal halogen tungsten lamp made of the same material as the high-power halogen tungsten lamp. In this way, the radiation efficiency of the halogen tungsten lamp after power-off can be quantitatively measured. In the other measuring system, a wide-spectrum power meter was installed far away from the halogen tungsten lamp; thus, the lamp can be regarded as a point light source. The radiation efficiency of residual energy from the halogen tungsten lamp was computed on the basis of geometrical relations. The results show that the halogen tungsten lamp's radiation efficiency was improved with power-on time but did not change under constant power-on time/energy. All the tested halogen tungsten lamps reached 89.3% of radiation efficiency at 50 s after power-on. After power-off, the residual energy in the halogen tungsten lamp gradually dropped to less than 10% of the initial radiation power, and the radiation efficiency changed with time. The final total radiation energy was decided by the halogen tungsten lamp's radiation efficiency, the radiation efficiency of residual energy, and the total power consumption. The measuring uncertainty of total radiation energy was 2.4% (here, the confidence factor is two).

On the application of CaF2:Eu and SrF2:Eu phosphors in LED based phototherapy lamp

NASA Astrophysics Data System (ADS)

Belsare, P. D.; Moharil, S. V.; Joshi, C. P.; Omanwar, S. K.

2013-06-01

In the last few years the interest of scientific community has been increased towards solid state lighting based on LEDs because of their superior advantages over the conventional fluorescent lamps. As the GaN based LEDs are easily available efforts of the researchers are now on making the new phosphors which are excitable in the near UV region (360-400nm) for solid state lighting. This paper reports the photoluminescence characteristics of CaF2:Eu and SrF2:Eu phosphor prepared by wet chemical method. The violet emission of these phosphors with near UV excitation can be useful in making a phototherapy lamp based on LEDs for treating various skin diseases like acne vulgaris and hyperbilirubinemia.

Pilot project in rural western Madhya Pradesh, India, to assess the feasibility of using LED and solar-powered lanterns to remove kerosene lamps and related hazards from homes.

PubMed

Chamania, S; Chouhan, R; Awasthi, A; Bendell, R; Marsden, N; Gibson, J; Whitaker, I S; Potokar, T S

2015-05-01

Globally, 300,000 deaths are estimated to occur annually and the incidence is far greater as a large majority of burns are small and go unreported. Ninety-five percent of the global burden of burns is found in low- and middle-income countries; however, there is relatively little in the literature regarding effective primary prevention in these areas. Flame is the most common cause of burn in Madhya Pradesh, the central state of India. The most common demographic among the burn unit inpatient of Choithram hospital Indore, is young women from 21 to 40 years of age, whose burns are primarily caused by kerosene lamps. A non electrical source of illumination is essential for every household in rural areas due to the infrequent and poor power supply. At the baseline, 23 kerosene lamp burns were reported by villagers in the past 5 years among the study population of this pilot project. A pilot project to investigate the strategies for reducing the incidence of domestic burns in rural villages around the city of Indore was performed, by replacing kerosene lamps with safer and more sustainable alternatives, including solar-powered and light-emitting diode (LED) lamps. A total of 1042 households were randomly chosen from 18 villages within the Malwa region of Madhya Pradesh (population of 28,825) to receive the alternative light source (670 LED and 372 solar lamps). We investigated the efficacy of this strategy of reducing the incidence of burns, measured the social acceptance by villagers, and quantified the cost implications and availability of LED lamps in rural communities with a high incidence of burns. Replacing kerosene lamps with LED and solar alternatives was deemed socially acceptable by 99.34% of the participants and reduced the cost of lighting for impoverished rural villagers by 85% over 1 year. We successfully demonstrated a significant decrease in the use of kerosene lamps (p<0.01). More evidence is required to investigate the efficacy of this strategy in reducing burns. This pilot study highlights the viability of the approach of replacing kerosene lamps as an effective primary prevention strategy for reducing burns in rural areas. However, barriers remain to the wider adoption of these lamps, including accessibility and availability for the populations of rural India. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Efficiency enhancement of blue light emitting diodes by eliminating V-defects from InGaN/GaN multiple quantum well structures through GaN capping layer control

NASA Astrophysics Data System (ADS)

Tsai, Sheng-Chieh; Li, Ming-Jui; Fang, Hsin-Chiao; Tu, Chia-Hao; Liu, Chuan-Pu

2018-05-01

A facile method for fabricating blue light-emitting diodes (B-LEDs) with small embedded quantum dots (QDs) and enhanced light emission is demonstrated by tuning the temperature of the growing GaN capping layer to eliminate V-defects. As the growth temperature increases from 770 °C to 840 °C, not only does the density of the V-defects reduce from 4.12 ∗ 108 #/cm2 nm to zero on a smooth surface, but the QDs also get smaller. Therefore, the growth mechanism of smaller QDs assisted by elimination of V-defects is discussed. Photoluminescence and electroluminescence results show that smaller embedded QDs can improve recombination efficiency, and thus achieve higher peak intensity with smaller peak broadening. Accordingly, the external quantum efficiency of the B-LEDs with smaller QDs is enhanced, leading to a 6.8% increase in light output power in lamp-form package LEDs.

Portable NIR bottled liquid explosive detector

NASA Astrophysics Data System (ADS)

Itozaki, Hideo; Ono, Masaki; Ito, Shiori; Uekawa, Keisuke; Miyato, Yuji; Sato-Akaba, Hideo

2016-05-01

A near infrared bottled liquid scanner has been developed for security check at airports for anti-terrorism. A compact handheld liquid scanner has been developed using an LED as a light source, instead of a halogen lamp. An LED has much smaller size, longer life time and lower power consumption than those of the lamp. However, it has narrower wave band. Here, we tried to use LEDs to scan liquids and showed the possibility that LEDs can be used as a light source of liquid detector.

BiliLED low cost neonatal phototherapy, from prototype to industry

NASA Astrophysics Data System (ADS)

Geido, Daniel; Failache, Horacio; Simini, Franco

2007-11-01

BiliLED is a phototherapy instrument designed to reduce bilirrubin blood rates in new born babies with jaundice. The light source is centred at 470 nm with a bandwidth of 35 nm and includes a matrix of 196 (14×14) InGaN LEDs. The optical elements are designed to maximize the light intensity useful for treatment, with a small number of LEDs in a compact and low cost unit. The optic array is such that every LED illuminates all the treatment area, which ensures redundancy and, thus, a high reliability not to be found in single-lamp instruments. Thermal dissipation and cost of BiliLED are both an order-of-magnitude smaller than conventional therapy lamps. BiliLED adjusts coetaneous irradiation with a feedback loop to compensate the loss or aging of LEDs achieving a calibrated light source for over a decade of use. A clinical trial in 20 hyperbilirrubinaemia patients shows 16% bilirrubin degradation within 24 hours of treatment, higher than most lamp phototherapy instruments. The steps from prototype to commercial model are described.

In vitro assessment of pulp chamber temperature of different teeth submitted to dental bleaching associated with LED/laser and halogen lamp appliances.

PubMed

Torres, Carlos Rocha Gomes; Caneppele, Taciana Marco Ferraz; Arcas, Felipe Carlos Dias; Borges, Alessandra Buhler

2008-01-01

This study sought to assess the pulp chamber temperature in different groups of human teeth that had been bleached using hydrogen peroxide gel activated with halogen lamps or hybrid LED/laser appliances. Four groups of ten teeth (maxillary central incisors, mandibular incisors, mandibular canines, and maxillary canines) were used. A digital thermometer with a K-type thermocouple was placed inside pulp chambers that had been filled with thermal paste. A 35% hydrogen peroxide-based red bleaching gel was applied to all teeth and photocured for a total of three minutes and 20 seconds (five activations of 40 seconds each), using light from an LED/laser device and a halogen lamp. The temperatures were gauged every 40 seconds and the data were analyzed by three-way ANOVA, followed by Tukey's test. Regardless of the light source, statistically significant differences were observed between the groups of teeth. The mean temperature values (+/- SD) were highest for maxillary central incisors and lowest for mandibular canines. The halogen lamp appliance produced more pulp chamber heating than the LED/laser appliance. The increase in irradiation time led to a significant increase in temperature.

Demonstration of LED Retrofit Lamps at the Jordan Schnitzer Museum of Art

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

Miller, Naomi J.

The Jordan Schnitzer Museum of Art in Eugene, Oregon, houses a remarkable permanent collection of Asian art and antiquities, modern art, and sculpture, and also hosts traveling exhibitions. In the winter and spring of 2011, a series of digital photographs by artist Chris Jordan, titled "Running the Numbers," was exhibited in the Coeta and Donald Barker Special Exhibitions Gallery. These works graphically illustrate waste (energy, money, health, consumer objects, etc.) in contemporary culture. The Bonneville Power Administration and the Eugene Water and Electricity Board provided a set of Cree 12W light-emitting diode (LED) PAR38 replacement lamps (Cree LRP38) for themore » museum to test for accent lighting in lieu of their standard Sylvania 90W PAR38 130V Narrow Flood lamps (which draw 78.9W at 120V). At the same time, the museum tested LED replacement lamps from three other manufacturers, and chose the Cree lamp as the most versatile and most appropriate color product for this exhibit. The lamps were installed for the opening of the show in January 2011. This report describes the process for the demonstration, the energy and economic results, and results of a survey of the museum staff and gallery visitors on four similar clusters of art lighted separately by four PAR38 lamps.« less

Quality engineering tools focused on high power LED driver design using boost power stages in switch mode

NASA Astrophysics Data System (ADS)

Ileana, Ioan; Risteiu, Mircea; Marc, Gheorghe

2016-12-01

This paper is a part of our research dedicated to high power LED lamps designing. The boost-up selected technology wants to meet driver producers' tendency in the frame of efficiency and disturbances constrains. In our work we used modeling and simulation tools for implementing scenarios of the driver work when some controlling functions are executed (output voltage/ current versus input voltage and fixed switching frequency, input and output electric power transfer versus switching frequency, transient inductor voltage analysis, and transient out capacitor analysis). Some electrical and thermal stress conditions are also analyzed. Based on these aspects, a high reliable power LED driver has been designed.

A lamp light-emitting diode-induced fluorescence detector for capillary electrophoresis.

PubMed

Xu, Jing; Xiong, Yan; Chen, Shiheng; Guan, Yafeng

2008-07-15

A light-emitting diode-induced fluorescence detector (LED-FD) for capillary electrophoresis was constructed and evaluated. A lamp LED with an enhanced emission spectrum and a band pass filter was used as the excitation light source. Refractive index matching fluid (RIMF) was used in the detection cell to reduce scattering light and the noise level. The limit of detection (LOD) for fluorescein was 1.5 nM (SNR=3). The system exhibited linear responses in the range of 1 x 10(-8) to 5 x 10(-6)M (R=0.999). Application of the lamp LED-FD for the analysis of FITC-labeled ephedra herb extract by capillary electrophoresis was demonstrated.

Light Source

NASA Technical Reports Server (NTRS)

1993-01-01

Research on food growth for long duration spacecraft has resulted in a light source for growing plants indoors known as Qbeam, a solid state light source consisting of a control unit and lamp. The light source, manufactured by Quantum Devices, Inc., is not very hot, although it generates high intensity radiation. When Ron Ignatius, an industrial partner of WCSAR, realized that terrestrial plant research lighting was not energy efficient enough for space use, he and WCSAR began to experiment with light emitting diodes. A line of LED products was developed, and QDI was formed to market the technology. An LED-based cancer treatment device is currently under development.

Evaluating potential spectral impacts of various artificial lights on melatonin suppression, photosynthesis, and star visibility.

PubMed

Aubé, Martin; Roby, Johanne; Kocifaj, Miroslav

2013-01-01

Artificial light at night can be harmful to the environment, and interferes with fauna and flora, star visibility, and human health. To estimate the relative impact of a lighting device, its radiant power, angular photometry and detailed spectral power distribution have to be considered. In this paper we focus on the spectral power distribution. While specific spectral characteristics can be considered harmful during the night, they can be considered advantageous during the day. As an example, while blue-rich Metal Halide lamps can be problematic for human health, star visibility and vegetation photosynthesis during the night, they can be highly appropriate during the day for plant growth and light therapy. In this paper we propose three new indices to characterize lamp spectra. These indices have been designed to allow a quick estimation of the potential impact of a lamp spectrum on melatonin suppression, photosynthesis, and star visibility. We used these new indices to compare various lighting technologies objectively. We also considered the transformation of such indices according to the propagation of light into the atmosphere as a function of distance to the observer. Among other results, we found that low pressure sodium, phosphor-converted amber light emitting diodes (LED) and LED 2700 K lamps filtered with the new Ledtech's Equilib filter showed a lower or equivalent potential impact on melatonin suppression and star visibility in comparison to high pressure sodium lamps. Low pressure sodium, LED 5000 K-filtered and LED 2700 K-filtered lamps had a lower impact on photosynthesis than did high pressure sodium lamps. Finally, we propose these indices as new standards for the lighting industry to be used in characterizing their lighting technologies. We hope that their use will favor the design of new environmentally and health-friendly lighting technologies.

Evaluating Potential Spectral Impacts of Various Artificial Lights on Melatonin Suppression, Photosynthesis, and Star Visibility

PubMed Central

Aubé, Martin; Roby, Johanne; Kocifaj, Miroslav

2013-01-01

Artificial light at night can be harmful to the environment, and interferes with fauna and flora, star visibility, and human health. To estimate the relative impact of a lighting device, its radiant power, angular photometry and detailed spectral power distribution have to be considered. In this paper we focus on the spectral power distribution. While specific spectral characteristics can be considered harmful during the night, they can be considered advantageous during the day. As an example, while blue-rich Metal Halide lamps can be problematic for human health, star visibility and vegetation photosynthesis during the night, they can be highly appropriate during the day for plant growth and light therapy. In this paper we propose three new indices to characterize lamp spectra. These indices have been designed to allow a quick estimation of the potential impact of a lamp spectrum on melatonin suppression, photosynthesis, and star visibility. We used these new indices to compare various lighting technologies objectively. We also considered the transformation of such indices according to the propagation of light into the atmosphere as a function of distance to the observer. Among other results, we found that low pressure sodium, phosphor-converted amber light emitting diodes (LED) and LED 2700 K lamps filtered with the new Ledtech’s Equilib filter showed a lower or equivalent potential impact on melatonin suppression and star visibility in comparison to high pressure sodium lamps. Low pressure sodium, LED 5000 K-filtered and LED 2700 K-filtered lamps had a lower impact on photosynthesis than did high pressure sodium lamps. Finally, we propose these indices as new standards for the lighting industry to be used in characterizing their lighting technologies. We hope that their use will favor the design of new environmentally and health-friendly lighting technologies. PMID:23861808

EDITORIAL: LED light sources (light for the future) LED light sources (light for the future)

NASA Astrophysics Data System (ADS)

Grandjean, N.

2010-09-01

Generating white light from electricity with maximum efficacy has been a long quest since the first incandescent lamp was invented by Edison at the end of the 19th century. Nowadays, semiconductors are making reality the holy grail of converting electrons into photons with 100% efficiency and with colours that can be mixed for white light illumination. The revolution in solid-state lighting (SSL) dates to 1994 when Nakamura reported the first high-brightness blue LED based on GaN semiconductors. Then, white light was produced by simply combining a blue dye with a yellow phosphor. After more than a decade of intensive research the performance of white LEDs is quite impressive, beating by far the luminous efficacy of compact fluorescent lamps. We are likely close to replacing our current lighting devices by SSL lamps. However, there are still technological and fabrication cost issues that could delay large market penetration of white LEDs. Interestingly, SSL may create novel ways of using light that could potentially limit electricity saving. Whatever the impact of SSL, it will be significant on our daily life. The purpose of this special cluster issue is to produce a snapshot of the current situation of SSL from different viewing angles. In an introductory paper, Tsao and co-workers from Sandia National Laboratories, present an energy-economics perspective of SSL considering societal changes and SSL technology evolution. In a second article, Narukawa et al working at Nichia Corporation—the pioneer and still the leading company in SSL—describe the state of the art of current research products. They demonstrate record performance with white LEDs exhibiting luminous efficacy of 183 lm W-1 at high-current injection. Then, a series of topical papers discuss in detail various aspects of the physics and technology of white LEDs Carrier localization in InGaN quantum wells has been considered the key to white LEDs' success despite the huge density of defects. A comprehensive review of the different localization mechanisms and their implication for internal quantum efficiency (IQE) is proposed by Oliver and co-workers from Cambridge University. When discussing IQE in InGaN-based LEDs, the efficiency droop at high-current injection always emerges, which is a major concern for the future of SSL technology. Here, a collaborative work between Samsung and the Gwangju Institute of Science and Technology (Korea) proves that a specific design of the active region can limit this detrimental effect. Once the issue of the IQE is solved, one still has to let the photons out of the chip. Matioli and Weisbuch from the University of California at Santa Barbara introduce the use of photonic crystals (PhCs) to improve light extraction efficiency. They describe different approaches to overcoming the main limitation of LEDs when implementing surface PhCs. The technology of SSL, and in particular of colour rendering, is tackled by Zukauskas et al who studied in detail different white light sources. They show that extreme colour-fidelity indices need to cover the entire spectrum, with a broad-band at 530-610 nm and a component beyond 610 nm. Then, the reliability of GaN-based LEDs is discussed in the paper of Meneghesso and co-workers. The authors consider the most important physical mechanisms that are (i) the degradation of the active layer of LEDs, (ii) the degradation of the package/phosphor system, (iii) the failure of GaN-based LEDs against electrostatic discharge. Finally, GaN LEDs on silicon developed in the group of Egawa at the Nagoya Institute of Technology are presented. This technology could allow a significant decrease in the fabrication cost of white LEDs.

Visible-Light-Responsive Catalyst Development for Volatile Organic Carbon Remediation Project

NASA Technical Reports Server (NTRS)

Zeitlin, Nancy; Hintze, Paul E.; Coutts, Janelle

2015-01-01

Photocatalysis is a process in which light energy is used to 'activate' oxidation/reduction reactions. Unmodified titanium dioxide (TiO2), a common photocatalyst, requires high-energy UV light for activation due to its large band gap (3.2 eV). Modification of TiO2 can reduce this band gap, leading to visible-light-responsive (VLR) photocatalysts. These catalysts can utilize solar and/or visible wavelength LED lamps as an activation source, replacing mercury-containing UV lamps, to create a "greener," more energy-efficient means for air and water revitalization. Recently, KSC developed several VLR catalysts that, on preliminary evaluation, possessed high catalytic activity within the visible spectrum; these samples out-performed existing commercial VLR catalysts.

Application of Wireless Intelligent Control System for HPS Lamps and LEDs Combined Illumination in Road Tunnel

PubMed Central

Lai, Jinxing; Qiu, Junling; Chen, Jianxun; Wang, Yaqiong; Fan, Haobo

2014-01-01

Because of the particularity of the environment in the tunnel, the rational tunnel illumination system should be developed, so as to optimize the tunnel environment. Considering the high cost of traditional tunnel illumination system with high-pressure sodium (HPS) lamps as well as the effect of a single light source on tunnel entrance, the energy-saving illumination system with HPS lamps and LEDs combined illumination in road tunnel, which could make full use of these two kinds of lamps, was proposed. The wireless intelligent control system based on HPS lamps and LEDs combined illumination and microcontrol unit (MCU) Si1000 wireless communication technology was designed. And the remote monitoring, wireless communication, and PWM dimming module of this system were designed emphatically. Intensity detector and vehicle flow detector can be configured in wireless intelligent control system, which gather the information to the master control unit, and then the information is sent to the monitoring center through the Ethernet. The control strategies are got by the monitoring center according to the calculated results, and the control unit wirelessly sends parameters to lamps, which adjust the luminance of each segment of the tunnel and realize the wireless intelligent control of combined illumination in road tunnel. PMID:25587266

78 FR 68331 - Energy Conservation Program: Request for Exclusion of 100 Watt R20 Short Incandescent Reflector...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-14

... attempt to replace the same lamp that was previously installed. It is not typical consumer behavior to... energy conservation standards for certain commercial and industrial equipment and various consumer... Characteristics in Substitutes 1. Improved R20 Short Lamp 2. 60 W PAR16 Lamp 3. LED Lamps 4. Consumer Use of...

High efficiency environmental sampling with UV-cured peelable coatings (aka NuGoo project)

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

Henzl, Vladimir; Junghans, Sylvia Ann; Lakis, Rollin Evan

This report presents slides on CA Related Project (FY13-17); Environmental sampling by IAEA (not only) during CA; Decontamination gels; Cotton swipes vs. decon gel (FY15); Contamination removal study; The origins of the NuGoo; NuGoo – proof of concept; NuGoo – FY17 project ($250K); LED lamp – which one works and why; Selecting photoinitiator; Monomers and oligomers; Results.

Application of 265-nm UVC LED Lighting to Sterilization of Typical Gram Negative and Positive Bacteria

NASA Astrophysics Data System (ADS)

Lee, Yong Wook; Yoon, Hyung Do; Park, Jae-Hyoun; Ryu, Uh-Chan

2018-05-01

UV LED lightings have been displacing conventional UV lamps due to their high efficiency, long lifetime, etc. A sterilizing lighting was prepared by assembling a UV LED module composed of 265-nm UVC LEDs and a silica lens array with a driver module comprised of a driver IC controlling pulse width modulation and constant current. The silica lens array was designed and fabricated to focus UV beam and simultaneously to give a uniform light distribution over specimens. Then pasteurizing effect of the lighting was analyzed for four kinds of bacteria and one yeast which are dangerous to people with low immunity. Sterilizing tests on these germs were carried out at the both exposure distances of 10 and 100 mm for various exposure durations up to 600 s.

Design of a high-efficiency train headlamp with low power consumption using dual half-parabolic aluminized reflectors.

PubMed

Liang, Wei-Lun; Su, Guo-Dung J

2018-02-20

We propose a train headlamp system using dual half-circular parabolic aluminized reflectors. Each half-circular reflector contains five high-efficiency and small-package light-emitting diode (LED) chips, and the halves are 180° rotationally symmetric. For traffic safety, the headlamp satisfies the Code of Federal Regulations. To predict the pattern of illumination, an analytical derivation is developed for the optical path of a ray that is perpendicular to and emitted from the center of an LED chip. This ray represents the main ray emitted from the LED chip and is located at the maximum illuminance of the spot projected by the LED source onto a screen. We then analyze the design systematically to determine the locations of the LED chips in the reflector that minimize electricity consumption while satisfying reliability constraints associated with traffic safety. Compared to a typical train headlamp system with an incandescent or halogen lamp needing several hundred watts, the proposed system only uses 20.18 W to achieve the luminous intensity requirements.

Design for Manufacture and Assembly for Product Development (Case study : Emergency Lamp)

NASA Astrophysics Data System (ADS)

Ngatilah, Y.; Pulansari, F.; Ernawati, Dira; Pujiastuti, C.; Parwati, C. I.; Prasetyo, B.

2018-01-01

Community needs that are not primary but important in everyday life are lights for lighting. State electricity company (PLN) is experiencing limitations in supplying electricity for this puIDRose. Therefore emergency lights (emergency lights) are already marketed in the community, which limited function only illuminate a very limited space. Therefore we developed the design of energy saving lamps using “Light Emitting Diode” (LED) which can illuminate the whole house as well as functioning as mobile phone charger (HP). The method used is Design for Manufacture and Assembly (DFMA), with the result of design development The percentage increase in assembly efficiency (E) is 0.01071 - 0.00645 = 0.00426 or = 39.76%. The decrease in material costs is IDR 234,000 - IDR 214,000 = IDR 20,000 or = 8.54% .Development design is received because of more assembly efficiency than the initial design. Power usage on previous products with series and designs of the original product can last only 4-5 hours non-stop, while the development of the design can survive 9-10 hours 2x more energy efficient.

Light transmission and ultraviolet protection of contact lenses under artificial illumination.

PubMed

Artigas, José M; Navea, Amparo; García-Domene, M Carmen; Gené, Andrés; Artigas, Cristina

2016-04-01

To determine the spectral transmission of contact lenses (CLs), with and without an ultraviolet (UV) filter to evaluate their capacity for protection under UV radiation from artificial illumination (incandescent, fluorescent, xenon (Xe) lamps, or white LEDs (light-emitting diode)). The transmission curves of nine soft CLs were obtained by using a PerkinElmer Lambda 35 UV-vis spectrophotometer. A CIE standard was used for the emission spectra of incandescent and fluorescent lamps, and Xe lamps and white LEDs were measured by using an International Light Technologies ILT-950 spectroradiometer. Five of the nine soft CLs analysed state that they incorporate UV filters, but the other four do not specify anything in this regard. The spectral transmission of all the CLs studied is excellent in the visible region. The CLs with UV filters filter out this radiation more or less effectively. Xe lamps emit a part in the UV region. Incandescent, fluorescent and white LEDs do not emit at all in the UV. Incorporating UV filters is important when the illumination is from a Xe lamp since this light source emits in the UV region. This, however, does not occur with incandescent and fluorescent lamps or white LEDs. The CLs that do incorporate UV filters meet all the standard requirements that the U.S. FDA (Food and Drug Administration) has for UV-blocking CLs Class II (OcularScience, CooperVision and Neolens), and AcuvueMoist and HydronActifresh400 even comply with the stricter Class I. The CLs without UV filters let UVA, UVB and even some UVC through. Copyright © 2015. Published by Elsevier Ltd.

Design of a Borescope for Extravehicular Non-Destructive Applications

NASA Technical Reports Server (NTRS)

Bachnak, Rafic

2003-01-01

Anomalies such as corrosion, structural damage, misalignment, cracking, stress fiactures, pitting, or wear can be detected and monitored by the aid of a borescope. A borescope requires a source of light for proper operation. Today s current lighting technology market consists of incandescent lamps, fluorescent lamps and other types of electric arc and electric discharge vapor lamp. Recent advances in LED technology have made LEDs viable for a number of applications, including vehicle stoplights, traffic lights, machine-vision-inspection, illumination, and street signs. LEDs promise significant reduction in power consumption compared to other sources of light. This project focused on comparing images taken by the Olympus IPLEX, using two different light sources. One of the sources is the 50-W internal metal halide lamp and the other is a 1 W LED placed at the tip of the insertion tube. Images acquired using these two light sources were quantitatively compared using their histogram, intensity profile along a line segment, and edge detection. Also, images were qualitatively compared using image registration and transformation [l]. The gray-level histogram, edge detection, image profile and image registration do not offer conclusive results. The LED light source, however, produces good images for visual inspection by an operator. Analysis using pattern recognition using Eigenfaces and Gaussian Pyramid in face recognition may be more useful.

EDITORIAL: Special Issue on Light Sources

NASA Astrophysics Data System (ADS)

Wharmby, D. O.

2008-07-01

The papers in this Special Issue of Journal of Physics D: Applied Physics originate from the 11th International Symposium on the Science and Technology of Light Sources (LS:11) held at Fudan University, Shanghai, China, during 20 24 May 2007. Abstracts of all papers were published in the conference book Light Sources 2007 (Sheffield: FAST-LS) edited by Muqing Liu and R Devonshire. Special issues were produced after LS:9 and LS:10 and have proved to be well-cited and important sources of information for this community. The Symposia occur at three-year intervals. In this one over 200 papers were presented—the majority as posters—with ample time provided for active discussion. As all submitted papers had to be refereed in the normal way for J. Phys. D: Appl. Phys., I was concerned that too many submissions would overwhelm the small number of referees available in this area. To ensure a broad spread of interests and opinions, I invited 10 senior colleagues to give me their recommendations about who should be asked to submit papers for this Special Issue. The criteria were that the work should be new, complete and within the scope of the journal. As a result of their suggestions 42 authors were asked to submit papers. Not all authors were able to submit a manuscript in time and some, at my request, combined their work into a single paper. The 28 papers published here are the result of that process. The issue starts with a comprehensive review by Benilov of the remarkable progress that has been made in the past 15 years in understanding the behaviour of cathode and anode terminations in arcs. It is fair to say that we now have a fundamental understanding of the formerly baffling behaviour of spot and diffuse terminations, at least in the quasi-steady state. A number of following papers cover applications of this theory, extensions to time dependence and examination of the effects of the different gaseous atmospheres in which lighting arcs operate. Mercury has very great advantages for efficient discharge lighting, including high volatility, high electron collision cross-section and its 3P levels, which are a major factor in the high efficiency generation of UV. Unfortunately, it is somewhat toxic and therefore unwelcome in the environment. Most of the mercury used in lighting is in fluorescent lamps and these produce (at high efficiency) most of the artificial light on this planet. Finding an alternative is proving a difficult but nevertheless active research field (see the recent Special Cluster on Mercury-Free Discharges for Lighting, edited by M Haverlag, in J. Phys. D: Appl. Phys. volume 40, issue 13). The other approach is to reduce the amount of mercury in each lamp. Much has already been done but pressure for further reduction continues; Corrazza and Boffito review the current status. Developments in the behaviour of fluorescent lamp electrodes and in the ignition of fluorescent lamps are amongst the papers presented on this most important discharge. Major advances in the performance of LEDs have been made in recent years, although currently most LED lighting is used for signalling and decorative lighting; this is because LEDs cannot yet produce the light levels needed for general illumination at costs and efficiencies that compete with discharge lamps. Because of their specialized technology, papers from this area are somewhat under-represented in this issue. Papers on OLEDs and the specialized field of LED measurement are included. HID (high intensity discharge) lamps operate close to LTE at high temperatures and pressures in corrosive atmospheres. Research on materials has been very important for their development and is represented here in two papers. Diagnostics of HID have been crucial to securing agreement between models and experiment in HID lamps. Two papers are presented here on the spectroscopy of self-reversed lines, which provide very reliable results in lamps that typically have relatively poor optical quality. These are followed by further papers on emission spectroscopy. Amongst other diagnostics, the use of x-ray methods has proved of great importance in lamps with diffusing ceramic envelopes. Developments and applications of this technique are reported in three papers. Comparison of model and experiment on the behaviour of metal-halide and mercury HID arcs is covered in further papers with particular emphasis on instabilities and the interaction of diffusion and convection in the flows. The understanding of breakdown and ignition of HID lamps—so critical to reliable operation—has made substantial progress as exemplified by the final two papers. Many other interesting posters on these subjects and others were presented at the LS:11 meeting. I hope when some of this work is brought to a conclusion that it will also be published. Discharge lamps still provide the best combination of high luminous flux and efficiency for illumination. In the next few years it will be interesting to see how strongly this position will be challenged by the rapidly improving solid state light sources. My task in preparing this Special Issue would have been impossible without the help of my unnamed colleagues who spent considerable time and energy in short-listing possible papers; they know who they are and I am extremely grateful to them.

Glare effect for three types of street lamps based on White LEDs

NASA Astrophysics Data System (ADS)

Sun, Ching-Cherng; Jiang, Chong-Jhih; Chen, Yi-Chun; Yang, Tsung-Hsun

2014-05-01

This study is aimed to assess the glare effect from LED-based street lamps with three general optical designs, which are cluster LEDs with a single lens, a LED array accompany with a lens array, and a tilted LED array, respectively. Observation conditions were simulated based on various locations and viewing axes. Equivalent luminance calculations were used to reveal the glare levels of the three designs. The age effect for the calculated equivalent luminance was also examined for human eyes of people at the age of 40 or 60. The results demonstrate that among the three design types, a LED array accompany with a lens array causes relatively smaller glare for most viewing conditions.

Photocatalytic ozonation of terephthalic acid: a by-product-oriented decomposition study.

PubMed

Fuentes, Iliana; Rodríguez, Julia L; Poznyak, Tatyana; Chairez, Isaac

2014-11-01

Terephthalic acid (TA) is considered as a refractory model compound. For this reason, the TA degradation usually requires a prolonged reaction time to achieve mineralization. In this study, vanadium oxide (VxOy) supported on titanium oxide (TiO2) served as a photocatalyst in the ozonation of the TA with light-emitting diodes (LEDs), having a bandwidth centered at 452 nm. The modified catalyst (VxOy/TiO2) in combination with ozone and LEDs improved the TA degradation and its by-products. The results obtained by this system were compared with photolysis, single ozonation, catalytic ozonation, and photocatalytic ozonation of VxOy/TiO2 with UV lamp. The LED-based photocatalytic ozonation showed almost the same decomposition efficiency of the TA, but it was better in comparison with the use of UV lamp. The oxalic acid accumulation, as the final product of the TA decomposition, was directly influenced by either the presence of VxOy or/and the LED irradiation. Several by-products formed during the TA degradation, such as muconic, fumaric, and oxalic acids, were identified. Besides, two unidentified by-products were completely removed during the observed time (60 min). It was proposed that the TA elimination in the presence of VxOy/TiO2 as catalyst was carried out by the combination of different mechanisms: molecular ozone reaction, indirect mechanism conducted by ·OH, and the surface complex formation.

Comparative Study of Lettuce and Radish Grown Under Red and Blue LEDs and White Fluorescent Lamps

NASA Technical Reports Server (NTRS)

Mickens, Matthew A.; Massa, Gioia; Newsham, Gerard; Wheeler, Raymond; Birmele, Michele

2016-01-01

Growing vegetable crops in space will be an essential part of sustaining astronauts during long-range missions. To drive photosynthesis, red and blue light-emitting diodes (LEDs) have attracted attention because of their efficiency, longevity, small size, and safety. In efforts to optimize crop yield, there is also recent interest in analyzing the subtle effects of additional wavelengths on plant growth. For instance, since plants often look purplish gray under red and blue LEDs, the addition of green light allows easy recognition of disease and the assessment of plant health status. However, it is important to know if wavelengths outside the traditional red and blue wavebands have a direct effect on enhancing or hindering the mechanisms involved in plant growth. In this experiment, a comparative study was performed on two short cycle crops of red romaine lettuce (Lactuca sativa cv. "Outredgeous") and radish (Raphanus sativa cv. 'Cherry Bomb'), which were grown under two light treatments. The first treatment being red (630 nm) and blue (450 nm) LEDs alone, while the second treatment consisted of daylight tri-phosphor fluorescent lamps (CCT approximately 5000 K) at equal photosynthetic photon flux (PPF). The treatment effects were evaluated by measuring the fresh biomass produced, plant morphology and leaf dimensions, leaf chlorophyll content, and adenosine triphosphate (ATP) within plant leaf/storage root tissues.

Clinical and Spectrophotometric Evaluation of LED and Laser Activated Teeth Bleaching.

PubMed

Lo Giudice, R; Pantaleo, G; Lizio, A; Romeo, U; Castiello, G; Spagnuolo, G; Giudice, G Lo

2016-01-01

Auxiliary power sources (LED and laser) are used in in-office teeth bleaching techniques to accelerate the redox reaction of the whitening gel to increase ease of use, to improve comfort and safety, and to decrease the procedure time. The aim this study is to evaluate the efficiency of the teeth whitening procedures performed with hydrogen peroxide and carbamide peroxide, LED or Laser activated. 18 patients, affected by exogenous dyschromia, were treated with a bleaching agent composed by 35% hydrogen peroxide and 10% carbamide peroxide. They were divided into two groups: in the first group the bleaching agent was activated by a LED lamp; in the second group it was activated by a Laser diode lamp. Both groups were subjected to 3 bleaching cycle of 15' each. The chromatic evaluations were performed before and after one week from the treatment, using a chromatic scale and a spectrophotometer. The mean value of pre, post bleaching and follow-up were analyzed using a T-test, with results statistically significant for P<0,05. Results showed that the variations in brightness, chroma and hue are significantly influenced by the interaction between the whitening agent and the original colour of the teeth. Laser-activation has marginally improved the bleaching effectiveness. All patients treated with laser activation complained an increase in dental sensitivity. The use of laser-activating systems did not improve the efficacy of bleaching.

Effects of catalyst concentration and ultraviolet intensity on chemical mechanical polishing of GaN

NASA Astrophysics Data System (ADS)

Wang, Jie; Wang, Tongqing; Pan, Guoshun; Lu, Xinchun

2016-08-01

Effects of catalyst concentration and ultraviolet intensity on chemical mechanical polishing (CMP) of GaN were deeply investigated in this paper. Working as an ideal homogeneous substrate material in LED industry, GaN ought to be equipped with a smooth and flat surface. Taking the strong chemical stability of GaN into account, photocatalytic oxidation technology was adopted in GaN CMP process to realize efficient removal. It was found that, because of the improved reaction rate of photocatalytic oxidation, GaN material removal rate (MRR) increases by a certain extent with catalyst concentration increasing. Cross single line analysis on the surface after polishing by Phase Shift MicroXAM-3D was carried out to prove the better removal effect with higher catalyst concentration. Ultraviolet intensity field in H2O2-SiO2-based polishing system was established and simulated, revealing the variation trend of ultraviolet intensity around the outlet of the slurry. It could be concluded that, owing to the higher planarization efficiency and lower energy damage, the UV lamp of 125 W is the most appropriate lamp in this system. Based on the analysis, defects removal model of this work was proposed to describe the effects of higher catalyst concentration and higher power of UV lamp.

Dimming-discrete-multi-tone (DMT) for simultaneous color control and high speed visible light communication.

PubMed

Sung, Jiun-Yu; Chow, Chi-Wai; Yeh, Chien-Hung

2014-04-07

Visible light communication (VLC) using LEDs has attracted significant attention recently for the future secure, license-free and electromagnetic-interference (EMI)-free optical wireless communication. Dimming technique in LED lamp is advantageous for energy efficiency. Color control can be performed in the red-green-blue (RGB) LEDs by using dimming technique. It is highly desirable to employ dimming technique to provide simultaneous color and dimming control and high speed VLC. Here, we proposed and demonstrated a LED dimming control using dimming-discrete-multi-tone (DMT) modulation. High speed DMT-based VLC with simultaneous color and dimming control is demonstrated for the first time to the best of our knowledge. Demonstration and analyses for several modulation conditions and transmission distances are performed, for instance, demonstrating the data rate of 103.5 Mb/s (using RGB LED) with fast Fourier transform (FFT) size of 512.

EDITORIAL: Special Issue on advanced and emerging light sources Special Issue on advanced and emerging light sources

NASA Astrophysics Data System (ADS)

Haverlag, Marco; Kroesen, Gerrit; Ferguson, Ian

2011-06-01

The papers in this special issue of Journal of Physics D: Applied Physics (JPhysD) originate from the 12th International Symposium on the Science and Technology of Light Sources and the 3rd International Conference on White LEDs and Solid State Lighting, held 11-16 July 2010 at Eindhoven University. Abstracts of all papers presented at this combined conference were published in the Conference Proceedings LS-WLED 2010 by FAST-LS, edited by M Haverlag, G M W Kroesen and T Taguchi. Special issues of the previous three LS conferences have been well-cited and have proven to be an important source of information for the lighting community. The 2010 LS-Symposium was a combined conference with the White LED Conference in order to enhance the scope of this conference series towards new light source technologies such as LEDs and OLEDs, and this co-operation will be continued in the future. Given the faster technology development in these areas it was also decided to shorten the interval between conferences from three to two years. Well over 200 invited presentations, landmark presentations and poster contributions were presented at the 2010 LS-Symposium. The organizing committee have selected from these a number of outstanding contributions with a high technological content and invited the authors to submit a full paper in JPhysD. The criteria were that the work should not be a repetition of the work already published in the Proceedings, but should be new, complete, within the scope of JPhysD, and meeting the normal quality standards of this journal. After peer review a combined set of 18 papers is published in this JPhysD special issue. In addition, a number of lighting-application-orientated papers will be published in a special issue of Journal of Light & Visual Environment later in 2011. The papers in this special issue of JPhysD show that research in the science and technology of light sources still covers a broad set of subject areas which includes both 'classical' discharge light sources and (O)LED sources, and new concepts are still being added to the range of technologies that are being used in practice. A truly classic aspect of lamp operation is lumen maintenance, and despite being in use for almost 50 years, Na/Sc quartz metal halide lamps until recently still suffered from a strong lumen depreciation over life. This issue has been resolved to a large extent with the introduction of high-frequency operation. In the paper of Van Erk et al, indications are given as to why this mode of operation is so successful. Another classic theme in the area of discharge lamp sources is ignition, still a major issue. In two consecutive papers by Sobota et al, several aspects of the cold ignition of ceramic metal halide lamps are discussed, including statistical delay effects, the role of the driving voltage, and ignition aids. The ignition becomes more complex when mercury is left out of a metal halide lamp and this is clearly shown in the paper by Estupiñán et al. When not buffered by mercury, water impurities will give rise to the formation of hydrogen iodide, which is very volatile and a strongly electronegative species, thereby hampering the ignition process. Mercury-free metal halide lamps will potentially show very different spectral properties. This is shown in the paper by Käning et al, where use has been made of the ongoing improvements in ceramic lamp technology to make lamps with a high rare-earth iodide content. It was found that in such lamps the contribution of molecular lines can become so important that some lines even become self-reversed. This opens new possibilities for making high-quality white light sources without mercury while retaining the use of electrodes. High rare-earth content also changes the behaviour of electrodes as a result of the lowering of the work function due to gas-phase emitter effects. In the paper by Reinelt et al some clear examples of this effect are investigated as well as their dependence on the operational frequency in ceramic metal halide lamps. Despite the fact that ceramic metal halide lamps with electrodes have already been on the market for more than 15 years, the latest developments in materials and lamp-shaping technologies continue to push the limits of efficiency and colour quality of these lamps. In an effort to clarify the energy balance of these lamps, Rijke et al have shown that it is possible to deduce from integrated sphere measurements in the visible and IR region the complete energy balance of such lamps. This method will provide valuable insights to push the efficacy of HID technologies even further. New concepts based on discharges are also being proposed and some of these are also being introduced to the market. It is interesting to note that all of these concepts are either mercury-free or can easily be adapted to mercury-free versions. One such contender is the electrodeless HID lamp. In the paper by Gilliard et al it is shown how a cavity resonator can be effectively used to couple power into a capacitively coupled electrodeless metal halide lamp. In contrast, the paper by Hilbig et al shows a concept in which the power is inductively coupled. Both methods potentially offer more freedom in salt choice, and this is used in the paper by Hilbig et al to test various new molecular radiators including some oxygen-containing molecules. With a larger choice of applicable salt systems, it becomes even more important to know the thermodynamical properties of rare-earth molecules. A nice overview of these properties for the mono-halides is given in the paper by Mucklejohn. Operating at lower pressures is another concept; employment of phosphor-converted DBD and microplasma lamps is studied in the papers by Eden et al and Guivan et al. A relatively new concept based on pulsed operation of pure Xe discharges and phosphor conversion is described by Motomura et al. These papers show that there is still an abundance of developments in discharge-based light sources. However, the progress in the last few years in LED and OLED sources has been even greater. In the editorial for the LS-11 conference by previous guest editor David Wharmby, it was stated that most LED lighting was still mostly used for signalling and decorative sources. In the three years that have passed, things have changed considerably and we now see LED light sources entering every application, ranging from street lighting and parking lots to shop lighting and even greenhouses. Currently LED prices for traditional lighting applications are high, but they are dropping rapidly. The papers published in this special issue give some indications of things to come. The paper by Jamil et al deals with the possibility of using silicon wafers as substrate material instead of the now commonly used (but more expensive) sapphire substrates. This is attractive from a cost price point of view, but leads to an increased lattice mismatch and therefore strain-induced defects. In this paper it is shown that when using intermediate matching layers it is possible to retain the same electrical and optical properties as with structures on sapphire. Another aspect that directly relates to cost is efficiency and droop in green InGaN devices, which is addressed in the paper by Lee et al. They show that by providing a flow of trymethylindium prior to the growth of the quantum wells it is possible to significantly increase the internal quantum efficiency of green LEDs. Improvement of the optical out-coupling of InGaN LEDs is discussed by Mak et al, and it is found that localized plasmon resonance of metallic nanoparticles (and especially silver) can help to increase the optical out-coupling in the wavelength region of interest. Nanoparticles in the form of ZnO nanorods are described by Willander et al as a possibility for phosphor-free wavelength conversion on polymer (O)LEDs. More advanced functions besides light emission can be achieved with OLEDs and this is demonstrated in the article by Generali et al which describes various aspects of organic light-emitting (field) transistors based on different substrates. The guest editors of this special issue of Journal of Physics D: Applied Physics would like to thank all the colleagues who helped us identify this exhaustive collection of papers. There are too many people to list here, but we know them well and are grateful for their help.

Reducing Energy Consumption and CO2 One Street Lamp at a Time

NASA Astrophysics Data System (ADS)

Somssich, Peter

2011-11-01

Why wait for federal action on incentives to reduce energy use and address Greenhouse Gas (GHG) reductions (e.g. CO2), when we can take personal actions right now in our private lives and in our communities? One such initiative by private citizens working with Portsmouth NH officials resulted in the installation of energy reducing lighting products on Court St. and the benefits to taxpayers are still coming after over 4 years of operation. This citizen initiative to save money and reduce CO2 emissions, while only one small effort, could easily be duplicated in many towns and cities. Replacing old lamps in just one street fixture with a more energy efficient (Non-LED) lamp has resulted after 4 years of operation (˜15,000 hr. life of product) in real electrical energy savings of > 43. and CO2 emission reduction of > 465 lbs. The return on investment (ROI) was less than 2 years. This is much better than any financial investment available today and far safer. Our street only had 30 such lamps installed; however, the rest of Portsmouth (population 22,000) has at least another 150 street lamp fixtures that are candidates for such an upgrade. The talk will also address other energy reduction measures that green the planet and also put more green in the pockets of citizens and municipalities.

UV emissions from low energy artificial light sources.

PubMed

Fenton, Leona; Moseley, Harry

2014-01-01

Energy efficient light sources have been introduced across Europe and many other countries world wide. The most common of these is the Compact Fluorescent Lamp (CFL), which has been shown to emit ultraviolet (UV) radiation. Light Emitting Diodes (LEDs) are an alternative technology that has minimal UV emissions. This brief review summarises the different energy efficient light sources available on the market and compares the UV levels and the subsequent effects on the skin of normal individuals and those who suffer from photodermatoses. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Energy Efficiency Comparison between Compact Fluorescent Lamp and Common Light Bulb

ERIC Educational Resources Information Center

Tanushevsk, Atanas; Rendevski, Stojan

2016-01-01

For acquainting the students of applied physics and students of teaching physics with the concept of energy efficiency, electrical and spectral characteristics of two widely used lamps--integrated fluorescence lamp and common light bulb have been investigated. Characterization of the lamps has been done by measuring the spectral irradiance and…

Effects of wavelength and water quality on photodegradation of N-Nitrosodimethylamine (NDMA).

PubMed

Sakai, Hiroshi; Takamatsu, Tatsuro; Kosaka, Koji; Kamiko, Naoyuki; Takizawa, Satoshi

2012-10-01

N-Nitrosodimethylamine (NDMA) is a potent carcinogen that yields a cancer risk of 10(-6) at concentrations as low as 0.7 ng L(-1). Tentative guideline values are set at 3 ng L(-1) in California, USA; 9 ng L(-1) in Ontario, Canada; 40 ng L(-1) nationwide in Canada; and 100 ng L(-1) by the World Health Organization. NDMA is a great concern in treating reclaimed water as well as drinking water. UV degradation can be considered effective degradation method. A 1-log reduction of NDMA is achieved by 1000 mJ cm(-2) of a 254-nm low pressure (LP) mercury UV lamp. However, a higher degradation efficiency than that provided by LP lamps is desired in practical treatment. In this study, the effects of wavelength and water quality were investigated to achieve higher degradation efficiency. The effects of wavelength were examined by comparing three UV lamps: a 222-nm Kr Cl Excimer UV lamp, a 254-nm LP mercury UV lamp, and a 230- to 270-nm filtered medium pressure (FMP) mercury UV lamp. The 222-nm lamp and FMP lamp achieved 4 times and 2.8 times higher degradation efficiency, respectively, than the conventional 254-nm LP lamp. Effects on water quality were also simulated by using absorption spectrum data of nitrate solutions and process water from a drinking-water treatment plant. In the simulation, the 222-nm lamp was affected by UV-absorbing compounds in the water, whereas the FMP lamp showed more stable degradation efficiency. Appropriate use of these three types of lamps could enhance the efficiency of degradation of NDMA. Copyright © 2012 Elsevier Ltd. All rights reserved.

CALiPER Retail Lamps Study 3

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

none,

2014-02-01

This is a special CALiPER report on LED lamps available through the retail marketplace and targeted toward general consumers. It follows similar reports published in 2011 and 2012 (products purchased in 2010 and 2011), and is intended as a continuation that identifies long-term trends. For this report, products were selected to investigate specific hypotheses, rather than represent a sample of the increasingly large retail LED market.

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

PubMed

Renard, G; Leid, J

2016-05-01

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

Growth and photomorphogenesis of pepper plants under red light-emitting diodes with supplemental blue or far-red lighting

NASA Technical Reports Server (NTRS)

Brown, C. S.; Schuerger, A. C.; Sager, J. C.

1995-01-01

Light-emitting diodes (LEDs) are a potential irradiation source for intensive plant culture systems and photobiological research. They have small size, low mass, a long functional life, and narrow spectral output. In this study, we measured the growth and dry matter partitioning of 'Hungarian Wax' pepper (Capsicum annuum L.) plants grown under red LEDs compared with similar plants grown under red LEDs with supplemental blue or far-red radiation or under broad spectrum metal halide (MH) lamps. Additionally, we describe the thermal and spectral characteristics of these sources. The LEDs used in this study had a narrow bandwidth at half peak height (25 nm) and a focused maximum spectral output at 660 nm for the red and 735 nm for the far-red. Near infrared radiation (800 to 3000 nm) was below detection and thermal infrared radiation (3000 to 50,000 nm) was lower in the LEDs compared to the MH source. Although the red to far-red ratio varied considerably, the calculated phytochrome photostationary state (phi) was only slightly different between the radiation sources. Plant biomass was reduced when peppers were grown under red LEDs in the absence of blue wavelengths compared to plants grown under supplemental blue fluorescent lamps or MH lamps. The addition of far-red radiation resulted in taller plants with greater stem mass than red LEDs alone. There were fewer leaves under red or red plus far-red radiation than with lamps producing blue wavelengths. These results indicate that red LEDs may be suitable, in proper combination with other wavelengths of light, for the culture of plants in tightly controlled environments such as space-based plant culture systems.

Photoprotection and photoreception of intraocular lenses under xenon and white LED illumination.

PubMed

Artigas, J M; Navea, A; García-Domene, M C; Artigas, C; Lanzagorta, A

2016-05-01

To analyze the photoprotection and phototransmission that various intraocular lenses (IOLs) provide under the illumination of a xenon (Xe) lamp and white LEDs (light emitting diode). The spectral transmission curves of six representative IOLs were measured using a Perkin-Elmer Lambda 35 UV/VIS spectrometer. Various filtering simulations were performed using a Xe lamp and white LEDs. The spectral emissions of these lamps were measured with an ILT-950 spectroradiometer. The IOLs analyzed primarily show transmission of nearly 100% in the visible spectrum. In the ultraviolet (UV) region, the filters incorporated in the various IOLs did not filter equally, and some of them let an appreciable amount of UV through. The Xe lamp presented a strong emission of ultraviolet A (UVA), and its emission under 300nm was not negligible. The white LED did not present an appreciable emission under 380nm. The cut-off wavelength of most filters is between 380 and 400nm (Physiol Hydriol60C(®), IOLTECH E4T(®), Alcon SA60AT(®), Alcon IQ SN60WF(®)), so that their UV protection is very effective. Nonetheless, the IOL OPHTEC Oculaid(®) contains a filter that, when a Xe lamp is used, lets through up to 20% for 350nm and up to 15% for 300nm, which at this point is ultraviolet B (UVB). The OPHTEC(®) Artisan IOL has a transmission peak below 300nm, which must be taken into account under Xe illumination. White LEDs do not emit energy below 380nm, so no special protection is required in the UV region. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Optimized optical wireless channel for indoor and intra-vehicle communications: power distribution and SNR analysis

NASA Astrophysics Data System (ADS)

Shaaban, Rana; Faruque, Saleh

2018-01-01

Light emitting diodes - LEDs are modernizing the indoor illumination and replacing current incandescent and fluorescent lamps rapidly. LEDs have multiple advantages such as extremely high energy efficient, longer lifespan, and lower heat generation. Due to the ability to switch to different light intensity at a very fast rate, LED has given rise to a unique communication technology (visible light communication - VLC) used for high speed data transmission. By studying various kinds of commonly used VLC channel analysis: diffuse and line of sight channels, we presented a simply improved indoor and intra-vehicle visible light communication transmission model. Employing optical wireless communications within the vehicle, not only enhance user mobility, but also alleviate radio frequency interference, and increase efficiency by lowering the complexity of copper cabling. Moreover, a solution to eliminate ambient noise caused by environmental conditions is examined by using optical differential receiver. The simulation results show the improved received power distribution and signal to noise ratio - SNR.

Spectral quality may be used to alter plant disease development in CELSS

NASA Astrophysics Data System (ADS)

Schuerger, A. C.; Brown, C. S.

1994-11-01

Plants were grown under light emitting diode (LED) arrays with different spectral qualities to determine the effects of light on the development of tomato mosaic virus (ToMV) in peppers and powdery mildew on cucumbers. One LED array supplied 100% of the photosynthetic photon flux (PPF) at 660 nm, a second array supplied 90% of the PPF at 660 nm and 10% at 735 nm, and a third array supplied 98% of the PPF at 660 nm with 2% in the blue region (380-500 nm) supplied by blue fluorescent lamps. Control plants were grown under metal halide (MH) lamps. Pepper plants inoculated with ToMV and grown under 660 and 660/735 LED arrays showed marked increases in both the rate and the severity of symptoms as compared to inoculated plants grown under the MH lamp or 660/blue array. Pepper plants grown under the 660/blue array did not develop symptoms as rapidly as inoculated plants grown under the 660 or 660/735 arrays, but they did develop symptoms faster than inoculated plants grown under the MH lamp. The numbers of colonies of powdery mildew per leaf and the size of each colony were greatest on inoculated cucumber plants grown under the MH lamp.

Inactivation kinetics and efficiencies of UV-LEDs against Pseudomonas aeruginosa, Legionella pneumophila, and surrogate microorganisms.

PubMed

Rattanakul, Surapong; Oguma, Kumiko

2018-03-01

To demonstrate the effectiveness of UV light-emitting diodes (UV-LEDs) to disinfect water, UV-LEDs at peak emission wavelengths of 265, 280, and 300 nm were adopted to inactivate pathogenic species, including Pseudomonas aeruginosa and Legionella pneumophila, and surrogate species, including Escherichia coli, Bacillus subtilis spores, and bacteriophage Qβ in water, compared to conventional low-pressure UV lamp emitting at 254 nm. The inactivation profiles of each species showed either a linear or sigmoidal survival curve, which both fit well with the Geeraerd's model. Based on the inactivation rate constant, the 265-nm UV-LED showed most effective fluence, except for with E. coli which showed similar inactivation rates at 265 and 254 nm. Electrical energy consumption required for 3-log 10 inactivation (E E,3 ) was lowest for the 280-nm UV-LED for all microbial species tested. Taken together, the findings of this study determined the inactivation profiles and kinetics of both pathogenic bacteria and surrogate species under UV-LED exposure at different wavelengths. We also demonstrated that not only inactivation rate constants, but also energy efficiency should be considered when selecting an emission wavelength for UV-LEDs. Copyright © 2017 Elsevier Ltd. All rights reserved.

High-power modular LED-based illumination systems for mask-aligner lithography.

PubMed

Bernasconi, Johana; Scharf, Toralf; Vogler, Uwe; Herzig, Hans Peter

2018-04-30

Mask-aligner lithography is traditionally performed using mercury arc lamps with wavelengths ranging from 250 nm to 600 nm with intensity peaks at the i, g and h lines. Since mercury arc lamps present several disadvantages, it is of interest to replace them with high power light emitting diodes (LEDs), which recently appeared on the market at those wavelengths. In this contribution, we present a prototype of an LED-based mask-aligner illumination. An optical characterization is made and the prototype is tested in a mask-aligner. Very good performances are demonstrated. The measured uniformity in the mask plane is 2.59 ± 0.24 % which is within the uniformity of the standard lamp. Print tests show resolution of 1 micron in contact printing and of 3 microns in proximity printing with a proximity gap of 30 microns.

Characterization and optimization of an inkjet-printed smart textile UV-sensor cured with UV-LED light

NASA Astrophysics Data System (ADS)

Seipel, S.; Yu, J.; Periyasamy, A. P.; Viková, M.; Vik, M.; Nierstrasz, V. A.

2017-10-01

For the development of niche products like smart textiles and other functional high-end products, resource-saving production processes are needed. Niche products only require small batches, which makes their production with traditional textile production techniques time-consuming and costly. To achieve a profitable production, as well as to further foster innovation, flexible and integrated production techniques are a requirement. Both digital inkjet printing and UV-light curing contribute to a flexible, resource-efficient, energy-saving and therewith economic production of smart textiles. In this article, a smart textile UV-sensor is printed using a piezoelectric drop-on-demand printhead and cured with a UV-LED lamp. The UVcurable ink system is based on free radical polymerization and the integrated UVsensing material is a photochromic dye, Reversacol Ruby Red. The combination of two photoactive compounds, for which UV-light is both the curer and the activator, challenges two processes: polymer crosslinking of the resin and color performance of the photochromic dye. Differential scanning calorimetry (DSC) is used to characterize the curing efficiency of the prints. Color measurements are made to determine the influence of degree of polymer crosslinking on the developed color intensities, as well as coloration and decoloration rates of the photochromic prints. Optimized functionality of the textile UV-sensor is found using different belt speeds and lamp intensities during the curing process.

Energy efficient fluorescent ballasts. Phase I, final report

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

Stevens Luminoptics Corporation

1978-06-21

The development of a high-frequency electronic (Stevens) ballast for fluorescent lamps is described. It is claimed that use of this ballast could reduce use energy consumption by 1.2 to 2.5 percent. The Stevens ballast has a basic efficiency of 29 percent when used with conventional lamps. With the more efficient lamps, the efficiency increases drastically. The conventional ballast and lamp has an efficiacy of approximately 60 to 63 lumens per watt (LPW). With the Stevens ballast the efficiacy raises to between 75 and 80 lumens per watt. When the Stevens ballast is utilized with the newer high efficiency lamps themore » efficiacy increases to 90 to 95 lumens per watt or a full 51 percent improvement over conventional coil and core ballasts and 25 percent over the best high efficiency premium coil and core ballasts. In addition to its energy savings capabilities, this high frequency fluorescent lamp ballast has the advantages that it is a true retrofit device that is directly interchangeable with the conventional coil core ballast, and it is dimmable over a wide and continuous range. (LCLC)« less

Effect of light-emitting diode vs. fluorescent lighting on laying hens in aviary hen houses: Part 1 - Operational characteristics of lights and production traits of hens.

PubMed

Long, H; Zhao, Y; Wang, T; Ning, Z; Xin, H

2016-01-01

Light-emitting diode (LED) lights are becoming more affordable for agricultural applications. Despite many lab-scale studies concerning impact of LED on poultry, little research has been documented under field production conditions, especially for laying hens. This 15-month field study was carried out to evaluate the effects of LED vs. fluorescent (FL) lights on laying hens (Dekalb white breed) using 4 (2 pairs) aviary hen houses each at a nominal capacity of 50,000 hens. The evaluation was done regarding operational characteristics of the lights and hen production traits. The results show that spatial distribution of the LED light was less uniform than that of the FL light. Light intensity of the LED light decreased by 27% after 3,360 h use but remained quite steady from 3,360 to 5,760 h use. Eleven out of 762 (1.44%) LED lamps (new at onset of the study) in the 2 houses failed during the 15-month experiment period. The neck area of the LED lamp was hottest, presumably the primary reason for the lamp failure as cracks were noticed in the neck region of all failed LED lamps. No differences were observed in egg weight, hen-day egg production, feed use, and mortality rate between LED and FL regimens. However, hens under the FL had higher eggs per hen housed and better feed conversion than those under the LED during 20 to 70 wk production (P < 0.05). Hens under the LED tended to have less feather uniformity and insulation than those under the FL (P < 0.05). Moreover, hens under the LED showed a larger median avoidance distance than those under the FL at 36 wk age (P < 0.05), indicating that hens under the LED were more alert; but no difference at 60 wk age. More comparative research to quantify behavioral and production responses of different breeds of hens to LED vs. FL lighting seems warranted. © 2015 Poultry Science Association Inc.

CALiPER Report 22.1: Photoelectric Performance of LED MR16 Lamps

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

None, None

This report looks at the photoelectric performance of the same set of lamps assessed in Report 22, using commercially available transformers and dimmers as well as laboratory power supplies providing either AC or DC. The investigation explores several issues related to the testing and use of MR16 lamps in lighting systems and examines the range of performance that is possible for a given lamp model, based on the system to which it is connected.

PREFACE: Diagnostics for electrical discharge light sources: pushing the limits Diagnostics for electrical discharge light sources: pushing the limits

NASA Astrophysics Data System (ADS)

Zissis, Georges; Haverlag, Marco

2010-06-01

Light sources play an indispensable role in the daily life of any human being. Quality of life, health and urban security related to traffic and crime prevention depend on light and on its quality. In fact, every day approximately 30 billion electric light sources operate worldwide. These electric light sources consume almost 19% of worldwide electricity production. Finding new ways to light lamps is a challenge where the stakes are scientific, technological, economic and environmental. The production of more efficient light sources is a sustainable solution for humanity. There are many opportunities for not only enhancing the efficiency and reliability of lighting systems but also for improving the quality of light as seen by the end user. This is possible through intelligent use of new technologies, deep scientific understanding of the operating principles of light sources and knowledge of the varied human requirements for different types of lighting in different settings. A revolution in the domain of light source technology is on the way: high brightness light emitting diodes arriving in the general lighting market, together with organic LEDs (OLEDs), are producing spectacular advances. However, unlike incandescence, electrical discharge lamps are far from disappearing from the market. In addition, new generations of discharge lamps based on molecular radiators are becoming a reality. There are still many scientific and technological challenges to be raised in this direction. Diagnostics are important for understanding the fundamental mechanisms taking place in the discharge plasma. This understanding is an absolute necessity for system optimization leading to more efficient and high quality light sources. The studied medium is rather complex, but new diagnostic techniques coupled to innovative ideas and powerful tools have been developed in recent years. This cluster issue of seven papers illustrates these efforts. The selected papers cover all domains, from high to low pressure and dielectric barrier lamps, from breakdown to acoustic resonance. Especially in the domain of high pressure lamps, J J Curry shows how coherent and incoherent x-ray scattering can be used as an imaging technique adapted to lamps. J Hirsch et al treat the acoustic resonance phenomenon that seriously limits the frequency domain for high pressure lamp operation. M Jinno et al illustrate a method that allows for measuring Xe buffer gas pressure in Hg-free metal halide lamps for automotive applications. In the domain of low pressure lamps, M Gendre et al investigate the breakdown phase by means of optical and electrical diagnostic tools. The similarity rules used a long time ago for simulating plasma behaviour based on invariants are now serving as diagnostic tools, as shown in the paper by D Michael et al. N Dagang et al show how impurities can be detected in Hg-free electrodeless lamps and more particularly in dielectric barrier discharges emitting excimer radiation. The quality of light is illustrated by a final example by R Kozakov et al on how to qualify the light output from the lamp with respect to biological effects on humans.

Temperature analysis during bonding of brackets using LED or halogen light base units.

PubMed

Silva, Paulo César Gomes; De Fátima Zanirato Lizarelli, Rosane; Moriyama, Lílian Tan; De Toledo Porto Neto, Sizenando; Bagnato, Vanderlei Salvador

2005-02-01

The purpose of our investigation is to compare the intrapulpal temperature changes following blue LED system and halogen lamp irradiation at the enamel surface of permanent teeth. The fixation of brackets using composite resin is more comfortable and faster when using a photo-curable composite. Several light sources can be used: halogens, arc plasma, lasers, and recently blue LED systems. An important aspect to be observed during such a procedures is the temperature change. In this study, we have used nine human extracted permanent teeth: three central incisors, three lateral incisors, and three canines. Teeth were exposed to two light sources: blue LED system (preliminary commercial model LEC 470-II) and halogen lamp (conventional photo-cure equipment). The surface of teeth was exposed for 20, 40, and 60 sec at the buccal and lingual enamel surface with an angle of 45 degrees. Temperature values measured by a thermistor placed at pulpar chamber were read in time intervals of 1 sec. We obtained plots showing the temperature evolution as a function of time for each experiment. There is a correlation between heating quantity and exposition time of light source: with increasing exposition time, heating increases into the pulpal chamber. The halogen lamp showed higher heating than the LED system, which showed a shorter time of cooling than halogen lamp. The blue LED system seems like the indicated light source for photo-cure of composite resin during the bonding of brackets. The fixation of brackets using composite resin is more comfortable and faster when using a photo-curable composite. Blue LED equipment did not heat during its use. This could permit a shorter clinical time of operation and better performance.

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

Ton, My K.; Richman, Eric E.; Gilbride, Theresa L.

In August 2008 the Pacific Northwest National Laboratory (PNNL) conducted a light emitting diode (LED) residential lighting demonstration project for the U.S. Department of Energy (DOE), Office of Building Technologies, as part of DOE’s Solid State Lighting (SSL) Technology Demonstration Gateway Program. Two lighting technologies, an LED replacement for downlight lamps (bulbs) and an LED undercabinet lighting fixture, were tested in the demonstration which was conducted in two homes built for the 2008 Tour of Homes in Eugene, Oregon. The homes were built by the Lane County Home Builders Association (HBA), and Future B Homes. The Energy Trust of Oregonmore » (ETO) also participated in the demonstration project. The LED downlight product, the LR6, made by Cree LED Lighting Solutions acts as a screw-in replacement for incandescent and halogen bulbs in recessed can downlights. The second product tested is Phillips/Color Kinetics’ eW® Profile Powercore undercabinet fixture designed to mount under kitchen cabinets to illuminate the countertop and backsplash surfaces. Quantitative and qualitative measurements of light performance and electrical power usage were taken at each site before and after initially installed halogen and incandescent lamps were replaced with the LED products. Energy savings and simple paybacks were also calculated and builders who toured the homes were surveyed for their responses to the LED products. The LED downlight product drew 12 Watts of power, cutting energy use by 82% compared to the 65W incandescent lamp and by 84% compared to the 75W halogen lamp. The LED undercabinet fixture drew 10 watts, cutting energy use by 83% to 90% compared to the halogen product, which was tested at two power settings: a low power 60W setting and a high power 105W setting. The LED downlight consistently provided more light than the halogen and incandescent lamps in horizontal measurements at counter height and floor level. It also outperformed in vertical illuminance measurements taken on the walls, indicating better lateral dispersion of the light. The undercabinet fixture’s light output was midway between the low and high power halogen undercabinet fixture light outputs (35.8 foot candle versus 13.4 fc and 53.4 fc) but it produced a more uniform light (max/min ratio of 7.0 versus 10.8). The color correlated temperature (CCT, the blue or yellowness) of the LED light correlated well with the halogen and incandescent lights (2675 K vs 2700 K). The color rendering of the LED downlight also correlated well at 92 CRI compared to 100 CRI for the halogen and incandescent lamps. The LED undercabinet fixture had measures of 2880 K CCT and 71 CRI compared to the 2700 K and 100 CRI scores for the halogen undercabinet fixture. Builders who toured the homes were surveyed; they gave the LED downlight high marks for brightness, said the undercabinet improved shadows and glare and said both products improved overall visibility, home appearance, and home value. Paybacks on the LED downlight ranged from 7.6 years (assuming electricity cost of 11 c/kWh) to 13.5 years (at 5C/kWh). Paybacks on the LED undercabinet fixture in a new home ranged from 4.4 years (11c/kWh electricity) to 7.6 years (5c/kWh) based on product costs of $95 per LED downlight and $140 per LED undercabinet fixture at 3 hrs per day of usage for the downlight and 2 hrs per day for the undercabinet lighting.« less

Accelerated Stress Testing of Multi-Source LED Products: Horticulture Lamps and Tunable-White Modules

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

Davis, Lynn; Rountree, Kelley; Mills, Karmann

This report discusses the use of accelerated stress testing (AST) to provide insights into the long-term behavior of commercial products utilizing different types of mid-power LEDs (MP-LEDs) integrated into the same LED module. Test results are presented from two commercial lamps intended for use in horticulture applications and one tunable-white LED module intended for use in educational and office lighting applications. Each of these products is designed to provide a custom spectrum for their targeted applications and each achieves this goal in different ways. Consequently, a comparison of the long-term stability of these devices will provide insights regarding approaches thatmore » could be used to possibly lengthen the lifetime of SSL products.« less

Clinical and Spectrophotometric Evaluation of LED and Laser Activated Teeth Bleaching

PubMed Central

Lo Giudice, R.; Pantaleo, G.; Lizio, A.; Romeo, U.; Castiello, G.; Spagnuolo, G.; Giudice, G. Lo

2016-01-01

Background: Auxiliary power sources (LED and laser) are used in in-office teeth bleaching techniques to accelerate the redox reaction of the whitening gel to increase ease of use, to improve comfort and safety, and to decrease the procedure time. Objective: The aim this study is to evaluate the efficiency of the teeth whitening procedures performed with hydrogen peroxide and carbamide peroxide, LED or Laser activated. Method: 18 patients, affected by exogenous dyschromia, were treated with a bleaching agent composed by 35% hydrogen peroxide and 10% carbamide peroxide. They were divided into two groups: in the first group the bleaching agent was activated by a LED lamp; in the second group it was activated by a Laser diode lamp. Both groups were subjected to 3 bleaching cycle of 15’ each. The chromatic evaluations were performed before and after one week from the treatment, using a chromatic scale and a spectrophotometer. The mean value of pre, post bleaching and follow-up were analyzed using a T-test, with results statistically significant for P<0,05. Results: Results showed that the variations in brightness, chroma and hue are significantly influenced by the interaction between the whitening agent and the original colour of the teeth. Laser-activation has marginally improved the bleaching effectiveness. All patients treated with laser activation complained an increase in dental sensitivity. Conclusion: The use of laser-activating systems did not improve the efficacy of bleaching. PMID:27386010

Curing efficacy of a new generation high-power LED lamp.

PubMed

Yap, Adrian U J; Soh, M S

2005-01-01

This study investigated the curing efficacy of a new generation high-power LED lamp (Elipar Freelight 2 [N] 3M-ESPE). The effectiveness of composite cure with this new lamp was compared to conventional LED/halogen (Elipar Freelight [F], 3M-ESPE; Max [M], Dentsply-Caulk) and high-power halogen (Elipar Trilight [T], 3M-ESPE; Astralis 10 [A], Ivoclar Vivadent) lamps. Standard continuous (NS, FS, TS; MS), turbo (AT) and exponential (NE, FE, TE) curing modes of the various lights were examined. Curing efficacy of the various lights and modes were determined by measuring the top and bottom surface hardness of 2-mm thick composite specimens (Z100, 3M-ESPE) using a digital microhardness tester (n=5; load=500 g; dwell time=15 seconds) one hour after light polymerization. The hardness ratio was computed by dividing HK (Knoops Hardness) of the bottom surface by HK of the top surface. The data was analyzed using one-way ANOVA/Scheffe's test and Independent Samples t-test at significance level 0.05. Results of the statistical analysis were as follows: HK top--E, FE, NE > NS and NE > AT, TS, FS; HK bottom--TE, NE > NS; Hardness ratio--NS > FE and FS, TS > NE. No significant difference in HK bottom and hardness ratio was observed between the two modes of Freelight 2 and Max. Freelight 2 cured composites as effectively as conventional LED/halogen and high-power halogen lamps, even with a 50% reduction in cure time. The exponential modes of Freelight 2, Freelight and Trilight appear to be more effective than their respective standard modes.

Quenching of Unincorporated Amplification Signal Reporters in Reverse-Transcription Loop-Mediated Isothermal Amplification Enabling Bright, Single-Step, Closed-Tube, and Multiplexed Detection of RNA Viruses.

PubMed

Ball, Cameron S; Light, Yooli K; Koh, Chung-Yan; Wheeler, Sarah S; Coffey, Lark L; Meagher, Robert J

2016-04-05

Reverse-transcription-loop-mediated isothermal amplification (RT-LAMP) has frequently been proposed as an enabling technology for simplified diagnostic tests for RNA viruses. However, common detection techniques used for LAMP and RT-LAMP have drawbacks, including poor discrimination capability, inability to multiplex targets, high rates of false positives, and (in some cases) the requirement of opening reaction tubes postamplification. Here, we present a simple technique that allows closed-tube, target-specific detection, based on inclusion of a dye-labeled primer that is incorporated into a target-specific amplicon if the target is present. A short, complementary quencher hybridizes to unincorporated primer upon cooling down at the end of the reaction, thereby quenching fluorescence of any unincorporated primer. Our technique, which we term QUASR (for quenching of unincorporated amplification signal reporters, read "quasar"), does not significantly reduce the amplification efficiency or sensitivity of RT-LAMP. Equipped with a simple LED excitation source and a colored plastic gel filter, the naked eye or a camera can easily discriminate between positive and negative QUASR reactions, which produce a difference in signal of approximately 10:1 without background subtraction. We demonstrate that QUASR detection is compatible with complex sample matrices such as human blood, using a novel LAMP primer set for bacteriophage MS2 (a model RNA virus particle). Furthermore, we demonstrate single-tube duplex detection of West Nile virus (WNV) and chikungunya virus (CHIKV) RNA.

A lighting assembly based on red and blue light-emitting diodes as a lighting source for space agriculture

NASA Astrophysics Data System (ADS)

Avercheva, Olga; Berkovich, Yuliy A.; Smolyanina, Svetlana; Bassarskaya, Elizaveta; Zhigalova, Tatiana; Ptushenko, Vasiliy; Erokhin, Alexei

Light-emitting diodes (LEDs) are a promising lighting source for space agriculture due to their high efficiency, longevity, safety, and other factors. Assemblies based on red and blue LEDs have been recommended in literature, although not all plants show sufficient productivity in such lighting conditions. Adding of green LEDs proposed in some works was aimed at psychological support for the crew, and not at the improvement of plant growth. We studied the growth and the state of the photosynthetic apparatus in Chinese cabbage (Brassica chinensis L.) plants grown under red (650 nm) and blue (470 nm) light-emitting diodes (LEDs). Plants grown under a high-pressure sodium lamp (HPS lamp) were used as a control. The plants were illuminated with two photosynthetic photon flux levels: nearly 400 µE and about 100 µE. Plants grown under LEDs with 400 µE level, as compared to control plants, showed lower fresh weight, edible biomass, growth rate, and sugar content. The difference in fresh weight and edible biomass was even more pronounced in plants grown with 100 µE level; the data indicate that the adaptability of the test plants to insufficient lighting decreased. Under LEDs, we observed the decreasing of root growth and the absence of transition to the flowering stage, which points to a change in the hormonal balance in plants grown in such lighting conditions. We also found differences in the functioning of the photosynthetic apparatus and its reaction to a low lighting level. We have concluded that a lighting assembly with red and blue LEDs only is insufficient for the plant growth and productivity, and can bring about alterations in their adaptive and regulatory mechanisms. Further studies are needed to optimize the lighting spectrum for space agriculture, taking into account the photosynthetic, phototropic and regulatory roles of light. Using white LEDs or adding far-red and green LEDs might be a promising approach.

Deep ultraviolet semiconductor light sources for sensing and security

NASA Astrophysics Data System (ADS)

Shatalov, Max; Bilenko, Yuri; Yang, Jinwei; Gaska, Remis

2009-09-01

III-Nitride based deep ultraviolet (DUV) light emitting diodes (LEDs) rapidly penetrate into sensing market owing to several advantages over traditional UV sources (i.e. mercury, xenon and deuterium lamps). Small size, a wide choice of peak emission wavelengths, lower power consumption and reduced cost offer flexibility to system integrators. Short emission wavelength offer advantages for gas detection and optical sensing systems based on UV induced fluorescence. Large modulation bandwidth for these devices makes them attractive for frequency-domain spectroscopy. We will review present status of DUV LED technology and discuss recent advances in short wavelength emitters and high power LED lamps.

CALiPER Report 20.5: Chromaticity Shift Modes of LED PAR38 Lamps Operated in Steady-State Conditions

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

Davis, J. Lynn; Young, Joseph; Royer, Michael

2016-02-26

This report builds on CALiPER Report 20.4, focusing on the same 32 PAR38 lamps but investigating causes of color shift and parametric failures. It provides a tear-down analysis of the lamp models and performs additional analyses on the spectroradiometric data obtained using a specially developed automated long-term test apparatus.

Relationships between junction temperature, electroluminescence spectrum and ageing of light-emitting diodes

NASA Astrophysics Data System (ADS)

Vaskuri, Anna; Kärhä, Petri; Baumgartner, Hans; Kantamaa, Olli; Pulli, Tomi; Poikonen, Tuomas; Ikonen, Erkki

2018-04-01

We have developed spectral models describing the electroluminescence spectra of AlGaInP and InGaN light-emitting diodes (LEDs) consisting of the Maxwell-Boltzmann distribution and the effective joint density of states. One spectrum at a known temperature for one LED specimen is needed for calibrating the model parameters of each LED type. Then, the model can be used for determining the junction temperature optically from the spectral measurement, because the junction temperature is one of the free parameters. We validated the models using, in total, 53 spectra of three red AlGaInP LED specimens and 72 spectra of three blue InGaN LED specimens measured at various current levels and temperatures between 303 K and 398 K. For all the spectra of red LEDs, the standard deviation between the modelled and measured junction temperatures was only 2.4 K. InGaN LEDs have a more complex effective joint density of states. For the blue LEDs, the corresponding standard deviation was 11.2 K, but it decreased to 3.5 K when each LED specimen was calibrated separately. The method of determining junction temperature was further tested on white InGaN LEDs with luminophore coating and LED lamps. The average standard deviation was 8 K for white InGaN LED types. We have six years of ageing data available for a set of LED lamps and we estimated the junction temperatures of these lamps with respect to their ageing times. It was found that the LEDs operating at higher junction temperatures were frequently more damaged.

Light quality and efficiency of consumer grade solid state lighting products

NASA Astrophysics Data System (ADS)

Dam-Hansen, Carsten; Corell, Dennis Dan; Thorseth, Anders; Poulsen, Peter Behrensdorff

2013-03-01

The rapid development in flux and efficiency of Light Emitting Diodes (LED) has resulted in a flooding of the lighting market with Solid State Lighting (SSL) products. Many traditional light sources can advantageously be replaced by SSL products. There are, however, large variations in the quality of these products, and some are not better than the ones they are supposed to replace. A lack of quality demands and standards makes it difficult for consumers to get an overview of the SSL products. Here the results of a two year study investigating SSL products on the Danish market are presented. Focus has been on SSL products for replacement of incandescent lamps and halogen spotlights. The warm white light and good color rendering properties of these traditional light sources are a must for lighting in Denmark and the Nordic countries. 266 SSL replacement lamps have been tested for efficiency and light quality with respect to correlated color temperature and color rendering properties. This shows a trade-off between high color rendering warm white light and energy efficiency. The lumen and color maintenance over time has been investigated and results for products running over 11000 h will be presented. A new internet based SSL product selection tool will be shown. Here the products can be compared on efficiency, light quality parameters, thus providing a better basis for the selection of SSL products for consumers.

340 nm pulsed UV LED system for europium-based time-resolved fluorescence detection of immunoassays.

PubMed

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

2016-09-19

We report on the design, development and investigation of an optical system based on UV light emitting diode (LED) excitation at 340 nm for time-resolved fluorescence detection of immunoassays. The system was tested to measure cardiac marker Troponin I with a concentration of 200 ng/L in immunoassay. The signal-to-noise ratio was comparable to state-of-the-art Xenon flash lamp based unit with equal excitation energy and without overdriving the LED. We performed a comparative study of the flash lamp and the LED based system and discussed temporal, spatial, and spectral features of the LED excitation for time-resolved fluorimetry. Optimization of the suggested key parameters of the LED promises significant increase of the signal-to-noise ratio and hence of the sensitivity of immunoassay systems.

White light emitting diode as potential replacement of tungsten-halogen lamp for visible spectroscopy system: a case study in the measurement of mango qualities

NASA Astrophysics Data System (ADS)

Chiong, W. L.; Omar, A. F.

2017-07-01

Non-destructive technique based on visible (VIS) spectroscopy using light emitting diode (LED) as lighting was used for evaluation of the internal quality of mango fruit. The objective of this study was to investigate feasibility of white LED as lighting in spectroscopic instrumentation to predict the acidity and soluble solids content of intact Sala Mango. The reflectance spectra of the mango samples were obtained and measured in the visible range (400-700 nm) using VIS spectroscopy illuminated under different white LEDs and tungsten-halogen lamp (pro lamp). Regression models were developed by multiple linear regression to establish the relationship between spectra and internal quality. Direct calibration transfer procedure was then applied between master and slave lighting to check on the acidity prediction results after transfer. Determination of mango acidity under white LED lighting was successfully performed through VIS spectroscopy using multiple linear regression but otherwise for soluble solids content. Satisfactory results were obtained for calibration transfer between LEDs with different correlated colour temperature indicated this technique was successfully used in spectroscopy measurement between two similar light sources in prediction of internal quality of mango.

Utilization of multi-band OFDM modulation to increase traffic rate of phosphor-LED wireless VLC.

PubMed

Yeh, Chien-Hung; Chen, Hsing-Yu; Chow, Chi-Wai; Liu, Yen-Liang

2015-01-26

To increase the traffic rate in phosphor-LED visible light communication (VLC), a multi-band orthogonal frequency division multiplexed (OFDM) modulation is first proposed and demonstrated. In the measurement, we do not utilize optical blue filter to increase modulation bandwidth of phosphor-LED in the VLC system. In this proposed scheme, different bands of OFDM signals are applied to different LED chips in a LED lamp, this can avoid the power fading and nonlinearity issue by applying the same OFDM signal to all the LED chips in a LED lamp. Here, the maximum increase percentages of traffic rates are 41.1%, 17.8% and 17.8% under received illuminations of 200, 500 and 1000 Lux, respectively, when the proposed three-band OFDM modulation is used in the VLC system. In addition, the analysis and verification by experiments are also performed.

Design a light pattern of multiple concentric circles for LED fishing lamps using Fourier series and an energy mapping method.

PubMed

Shen, S C; Li, J S; Huang, M C

2014-06-02

Fourier series and an energy mapping method were used in this study to design a lens that produces a light pattern of multiple concentric circles (LPMCC) for a light-emitting diode (LED) fishing lamp. Fourier series were used to represent the light intensity distribution curve (LIDC) of the LPMCC light pattern. Energy mapping involves performing angular energy mapping based on the LIDCs of an LED light source and LPMCC to design a freeform lens. Type I and Type II LPMCC lenses were designed according to the phototaxis behavior of fish to create a LPMCC light pattern of interleaving light-dark zones that attracts fish shoals to stay in an area for a long period. The experimental results indicated that, in comparing the LIDCs of the Type I and II lenses with the respective simulation values, the normalized cross-correlation (NCC) value reached 96%. According to a 24-hour observation of the phototaxis of Poecilia reticulata to evaluate the effectiveness of the proposed light pattern to attract fish, when a fish shoal was habituated to a light source that emitted constant illumination light, it gradually moved away from the intense light zone and hovered around the junction of the light and dark zones. In the future, the design used in this study can be applied to LED fishing lamps to replace traditional fishing lamps.

Non-visual biological effects of light on human cognition, alertness, and mood

NASA Astrophysics Data System (ADS)

Li, Huaye; Wang, Huihui; Shen, Junfei; Sun, Peng; Xie, Ting; Zhang, Siman; Zheng, Zhenrong

2017-09-01

Light exerts non-visual effects on a wide range of biological functions and behavior apart from the visual effect. Light can regulate human circadian rhythms, like the secretion of melatonin and cortisol. Light also has influence on body's physiological parameters, such as blood pressure, heart rate and body temperature. However, human cognitive performance, alertness and mood under different lighting conditions have not been considered thoroughly especially for the complicated visual task like surgical operating procedure. In this paper, an experiment was conducted to investigate the cognition, alertness and mood of healthy participants in a simulated operating room (OR) in the hospital. A LED surgical lamp was used as the light source, which is mixed by three color LEDs (amber, green and blue). The surgical lamp is flexible on both spectrum and intensity. Exposed to different light settings, which are varied from color temperature and luminance, participants were asked to take psychomotor vigilance task (PVT) for alertness measurement, alphabet test for cognitive performance measurement, positive and negative affect schedule (PANAS) for mood measurement. The result showed the participants' cognitive performance, alertness and mood are related to the color temperature and luminance of the LED light. This research will have a guidance for the surgical lighting environment, which can not only enhance doctors' efficiency during the operations, but also create a positive and peaceful surgical lighting environment.

Optical CAD Utilization for the Design and Testing of a LED Streetlamp.

PubMed

Jafrancesco, David; Mercatelli, Luca; Fontani, Daniela; Sansoni, Paola

2017-08-24

The design and testing of LED lamps are vital steps toward broader use of LED lighting for outdoor illumination and traffic signalling. The characteristics of LED sources, in combination with the need to limit light pollution and power consumption, require a precise optical design. In particular, in every step of the process, it is important to closely compare theoretical or simulated results with measured data (obtained from a prototype). This work examines the various possibilities for using an optical CAD (Lambda Research TracePro ) to design and check a LED lamp for outdoor use. This analysis includes the simulations and testing on a prototype as an example; data acquired by measurement are inserted into the same simulation software, making it easy to compare theoretical and actual results.

Color adjustable LED driver design based on PWM

NASA Astrophysics Data System (ADS)

Du, Yiying; Yu, Caideng; Que, Longcheng; Zhou, Yun; Lv, Jian

2012-10-01

Light-emitting diode (LED) is a liquid cold source light source that rapidly develops in recent years. The merits of high brightness efficiency, long duration, high credibility and no pollution make it satisfy our demands for consumption and natural life, and gradually replace the traditional lamp-house-incandescent light and fluorescent light. However, because of the high cost and unstable drive circuit, the application range is restricted. To popularize the applications of the LED, we focus on improving the LED driver circuit to change this phenomenon. Basing on the traditional LED drive circuit, we adopt pre-setup constant current model and introduce pulse width modulation (PWM) control method to realize adjustable 256 level-grays display. In this paper, basing on human visual characteristics and the traditional PWM control method, we propose a new PWM control timing clock to alter the duty cycle of PWM signal to realize the simple gamma correction. Consequently, the brightness can accord with our visual characteristics.

Inductive tuners for microwave driven discharge lamps

DOEpatents

Simpson, James E.

1999-01-01

An RF powered electrodeless lamp utilizing an inductive tuner in the waveguide which couples the RF power to the lamp cavity, for reducing reflected RF power and causing the lamp to operate efficiently.

Anatomical features of pepper plants (Capsicum annuum L.) grown under red light-emitting diodes supplemented with blue or far-red light

NASA Technical Reports Server (NTRS)

Schuerger, A. C.; Brown, C. S.; Stryjewski, E. C.

1997-01-01

Pepper plants (Capsicum annuum L. cv., Hungarian Wax) were grown under metal halide (MH) lamps or light-emitting diode (LED) arrays with different spectra to determine the effects of light quality on plant anatomy of leaves and stems. One LED (660) array supplied 90% red light at 660 nm (25nm band-width at half-peak height) and 1% far-red light between 700-800nm. A second LED (660/735) array supplied 83% red light at 660nm and 17% far-red light at 735nm (25nm band-width at half-peak height). A third LED (660/blue) array supplied 98% red light at 660nm, 1% blue light between 350-550nm, and 1% far-red light between 700-800nm. Control plants were grown under broad spectrum metal halide lamps. Plants were gron at a mean photon flux (300-800nm) of 330 micromol m-2 s-1 under a 12 h day-night photoperiod. Significant anatomical changes in stem and leaf morphologies were observed in plants grown under the LED arrays compared to plants grown under the broad-spectrum MH lamp. Cross-sectional areas of pepper stems, thickness of secondary xylem, numbers of intraxylary phloem bundles in the periphery of stem pith tissues, leaf thickness, numbers of choloplasts per palisade mesophyll cell, and thickness of palisade and spongy mesophyll tissues were greatest in peppers grown under MH lamps, intermediate in plants grown under the 660/blue LED array, and lowest in peppers grown under the 660 or 660/735 LED arrays. Most anatomical features of pepper stems and leaves were similar among plants grown under 660 or 660/735 LED arrays. The effects of spectral quality on anatomical changes in stem and leaf tissues of peppers generally correlate to the amount of blue light present in the primary light source.

Anatomical features of pepper plants (Capsicum annuum L.) grown under red light-emitting diodes supplemented with blue or far-red light.

PubMed

Schuerger, A C; Brown, C S; Stryjewski, E C

1997-03-01

Pepper plants (Capsicum annuum L. cv., Hungarian Wax) were grown under metal halide (MH) lamps or light-emitting diode (LED) arrays with different spectra to determine the effects of light quality on plant anatomy of leaves and stems. One LED (660) array supplied 90% red light at 660 nm (25nm band-width at half-peak height) and 1% far-red light between 700-800nm. A second LED (660/735) array supplied 83% red light at 660nm and 17% far-red light at 735nm (25nm band-width at half-peak height). A third LED (660/blue) array supplied 98% red light at 660nm, 1% blue light between 350-550nm, and 1% far-red light between 700-800nm. Control plants were grown under broad spectrum metal halide lamps. Plants were gron at a mean photon flux (300-800nm) of 330 micromol m-2 s-1 under a 12 h day-night photoperiod. Significant anatomical changes in stem and leaf morphologies were observed in plants grown under the LED arrays compared to plants grown under the broad-spectrum MH lamp. Cross-sectional areas of pepper stems, thickness of secondary xylem, numbers of intraxylary phloem bundles in the periphery of stem pith tissues, leaf thickness, numbers of choloplasts per palisade mesophyll cell, and thickness of palisade and spongy mesophyll tissues were greatest in peppers grown under MH lamps, intermediate in plants grown under the 660/blue LED array, and lowest in peppers grown under the 660 or 660/735 LED arrays. Most anatomical features of pepper stems and leaves were similar among plants grown under 660 or 660/735 LED arrays. The effects of spectral quality on anatomical changes in stem and leaf tissues of peppers generally correlate to the amount of blue light present in the primary light source.

Beacon system based on light-emitting diode sources for runways lighting

NASA Astrophysics Data System (ADS)

Montes, Mario González; Vázquez, Daniel; Fernandez-Balbuena, Antonio A.; Bernabeu, Eusebio

2014-06-01

New aeronautical ground lighting techniques are becoming increasingly important to ensure the safety and reduce the maintenance costs of the plane's tracks. Until recently, tracks had embedded lighting systems whose sources were based on incandescent lamps. But incandescent lamps have several disadvantages: high energy consumption and frequent breakdowns that result in high maintenance costs (lamp average life-time is ˜1500 operating hours) and the lamp's technology has a lack of new lighting functions, such as signal handling and modification. To solve these problems, the industry has developed systems based on light-emitting diode (LED) technology with improved features: (1) LED lighting consumes one tenth the power, (2) it improves preventive maintenance (an LED's lifetime range is between 25,000 and 100,000 hours), and (3) LED lighting technology can be controlled remotely according to the needs of the track configuration. LEDs have been in use for more than three decades, but only recently, around 2002, have they begun to be used as visual aids, representing the greatest potential change for airport lighting since their inception in the 1920s. Currently, embedded LED systems are not being broadly used due to the specific constraints of the rules and regulations of airports (beacon dimensions, power system technology, etc.). The fundamental requirements applied to embedded lighting systems are to be hosted on a volume where the dimensions are usually critical and also to integrate all the essential components for operation. An embedded architecture that meets the lighting regulations for airport runways is presented. The present work is divided into three main tasks: development of an optical system to optimize lighting according to International Civil Aviation Organization, manufacturing prototype, and model validation.

Effects of illuminants and illumination time on lettuce growth, yield and nutritional quality in a controlled environment

NASA Astrophysics Data System (ADS)

Shen, Y. Z.; Guo, S. S.; Ai, W. D.; Tang, Y. K.

2014-07-01

Effects of illuminants and illumination time on the growth of lettuce were researched. Red-blue light-emitting diodes (LEDs, 90% red light +10% blue light) and white light fluorescent (WF) lamps were compared as the illuminants for plant cultivation. Under each type of illuminant, lettuce was grown at 4 illumination times: 12 h, 16 h, 20 h and 24 h, with the same light intensity of 600 μmolm-2s-1. The leaf net photosynthetic rate (Pn) under the two illuminants was comparable but the shape of lettuce was obviously affected by the illuminant. The WF lamps produced more compact plant, while red-blue LED resulted in less but longer leaves. However, the total leaf area was not significantly affected by the illuminant. The red-blue LED produced nearly same aboveground biomass with far less energy consumption relative to WF lamps. The underground biomass was lowered under red-blue LED in comparison with WF lamps. Red-blue LED could improve the nutritional quality of lettuce by increasing the concentration of soluble sugar and vitamin C (VC) and reducing the concentration of nitrate. Under each type of illuminant, longer illumination time resulted in higher Pn, more leaves and larger leaf area. The total chlorophyll concentration increased while the concentration ratio of chlorophyll a/b decreased with the extension of illumination time. Illumination time had highly significant positive correlation with biomass. Moreover, when total daily light input was kept the same, longer illumination time increased the biomass significantly as well. In addition, longer illumination time increased the concentration of crude fiber, soluble sugar and VC and reduced the concentration of nitrate. In summary, red-blue LEDs and 24 h illumination time were demonstrated to be more suitable for lettuce cultivation in the controlled environment.

Measuring the Photocatalytic Breakdown of Crystal Violet Dye using a Light Emitting Diode Approach

NASA Technical Reports Server (NTRS)

Ryan, Robert E.; Underwood, Lauren W.; O'Neal, Duane; Pagnutti, Mary; Davis, Bruce A.

2009-01-01

A simple method to estimate the photocatalytic reactivity performance of spray-on titanium dioxide coatings for transmissive glass surfaces was developed. This novel technique provides a standardized method to evaluate the efficiency of photocatalytic material systems over a variety of illumination levels. To date, photocatalysis assessments have generally been conducted using mercury black light lamps. Illumination levels for these types of lamps are difficult to vary, consequently limiting their use for assessing material performance under a diverse range of simulated environmental conditions. This new technique uses an ultraviolet (UV) gallium nitride (GaN) light emitting diode (LED) array instead of a traditional black light to initiate and sustain photocatalytic breakdown. This method was tested with a UV-resistant dye (crystal violet) applied to a titanium dioxide coated glass slide. Experimental control is accomplished by applying crystal violet to both titanium dioxide coated slides and uncoated control slides. A slide is illuminated by the UV LED array, at various light levels representative of outdoor and indoor conditions, from the dye side of the slide. To monitor degradation of the dye over time, a temperature-stabilized white light LED, whose emission spectrum overlaps with the dye absorption spectrum, is used to illuminate the opposite side of the slide. Using a spectrometer, the amount of light from the white light LED transmitted through the slide as the dye degrades is monitored as a function of wavelength and time and is subsequently analyzed. In this way, the rate of degradation for photocatalytically coated versus uncoated slide surfaces can be compared. Results demonstrate that the dye absorption decreased much more rapidly on the photocatalytically coated slides than on the control uncoated slides, and that dye degradation is dependent on illumination level. For photocatalytic activity assessment purposes, this experimental configuration and methodology minimizes many external variable effects and enables small changes in absorption to be measured. This research also compares the advantages of this innovative LED light source design over traditional mercury black light systems and non- LED lamp approaches. This novel technology begins to address the growing need for a standard method that can assess the performance of photocatalytic materials before deployment for large scale, real world use.

Feasibility of Ultraviolet Light Emitting Diodes as an Alternative Light Source for Photocatalysis

NASA Technical Reports Server (NTRS)

Levine, Langanf H.; Richards, Jeffrey T.; Soler, Robert; Maxik, Fred; Coutts, Janelle; Wheeler, Raymond M.

2011-01-01

The objective of this study was to determine whether ultraviolet light emitting diodes (UV-LEDs) could serve as an alternative photon source efficiently for heterogeneous photocatalytic oxidation (PCO). An LED module consisting of 12 high-power UV-A LEDs was designed to be interchangeable with a UV-A fluorescent black light blue (BLB) lamp in a Silica-Titania Composite (STC) packed bed annular reactor. Lighting and thermal properties were characterized to assess the uniformity and total irradiant output. A forward current of (I(sub F)) 100 mA delivered an average irradiance of 4.0 m W cm(exp -2), which is equivalent to the maximum output of the BLB, but the irradiance of the LED module was less uniform than that of the BLB. The LED- and BLB-reactors were tested for the oxidization of 50 ppmv ethanol in a continuous flow-through mode with 0.94 sec space time. At the same irradiance, the UV-A LED reactor resulted in a lower PCO rate constant than the UV-A BLB reactor (19.8 vs. 28.6 nM CO2 sec-I), and consequently lower ethanol removal (80% vs. 91%) and mineralization efficiency (28% vs. 44%). Ethanol mineralization increased in direct proportion to the irradiance at the catalyst surface. This result suggests that reduced ethanol mineralization in the LED- reactor could be traced to uneven irradiance over the photocatalyst, leaving a portion of the catalyst was under-irradiated. The potential of UV-A LEDs may be fully realized by optimizing the light distribution over the catalyst and utilizing their instantaneous "on" and "off' feature for periodic irradiation. Nevertheless, the current UV-A LED module had the same wall plug efficiency (WPE) of 13% as that of the UV-A BLB. These results demonstrated that UV-A LEDs are a viable photon source both in terms of WPE and PCO efficiency.

Emergency Lighting System

NASA Technical Reports Server (NTRS)

1994-01-01

When power outages occurred at Landmark Plastic Corporation, it took seven to twelve minutes for the primary mercury lamps to cool down enough to relight and two to seven minutes for the ELS incandescent lamps to relight. Production could not resume for as much as seven minutes. An article in NASA Tech Briefs describing the capabilities of photosensing devices led Landmark employee, Steve Keller to design a system now activated by any voltage loss in the main lamp circuit and coupled with photosensing devices used to keep them on until the primary mercury lamps reach full brightness.

A comparison of the antibacterial activity of the two methods of photodynamic therapy (using diode laser 810 nm and LED lamp 630 nm) against Enterococcus faecalis in extracted human anterior teeth.

PubMed

Asnaashari, Mohammad; Mojahedi, Seyed Masoud; Asadi, Zahra; Azari-Marhabi, Saranaz; Maleki, Alireza

2016-03-01

Failure of endodontic treatment is usually due to an inadequate disinfection of the root canal system. Enterococcus faecalis has been widely used as a valuable microbiological marker for in-vitro studies because of its ability to colonize in a biofilm like style in root canals, invading dentinal tubules and resistance to some endodontic treatments. The aim of this study was to investigate the antibacterial effects of two methods of photodynamic therapy using a light emitting diode lamp (LED lamp, 630 nm) and a diode laser (810 nm) on E. faecalis biofilms in anterior extracted human teeth. Fifty six single-rooted extracted teeth were used in this study. After routine root canal cleansing, shaping and sterilization, the teeth were incubated with E. faecalis for a period of two weeks. Teeth were then divided into two experimental groups (nu=23) and two control groups (nu=5). Teeth in one experimental group were exposed to a diode laser (810 nm), and in the other group samples were exposed to a LED lamp (630 nm). Intracanal bacterial sampling was done, and bacterial survival rate was then evaluated for each group. The Colony Forming Unit (CFU) in LED group (log10 CFUs=4.88±0.82) was significantly lower than the laser group (log CFUs=5.49±0.71) (p value=0.021). CFUs in positive control group (Log10 CFUs=10.96±0.44) were significantly higher than the treatment group (p˂0.001). No bacterial colony was found in negative control group. The results of this research show that photodynamic therapy could be an effective supplement in root canal disinfection. PDT using LED lamp was more effective than diode laser 810 nm in reducing CFUs of E. faecalis in human teeth. Copyright © 2015 Elsevier B.V. All rights reserved.

The Effect of Photon Source on Heterogeneous Photocatalytic Oxidation of Ethanol by a Silica-Titania Composite

NASA Technical Reports Server (NTRS)

Coutts, Janelle L.; Levine, Lanfang H.; Richards, Jeffrey T.; Mazyck, David W.

2011-01-01

The objective of this study was to distinguish the effect of photon flux (i.e., photons per unit time reaching a surface) from that of photon energy (i.e., wavelength) of a photon source on the silica-titania composite (STC)-catalyzed degradation of ethanol in the gas phase. Experiments were conducted in a bench-scale annular reactor packed with STC pellets and irradiated with either a UV-A fluorescent black light blue lamp ((gamma)max=365 nm) at its maximum light intensity or a UV-C germicidal lamp ((gamma)max=254 nm) at three levels of light intensity. The STC-catalyzed oxidation of ethanol was found to follow zero-order kinetics with respect to CO2 production, regardless of the photon source. Increased photon flux led to increased EtOH removal, mineralization, and oxidation rate accompanied by lower intermediate concentration in the effluent. The oxidation rate was higher in the reactor irradiated by UV-C than by UV-A (38.4 vs. 31.9 nM/s) at the same photon flux, with similar trends for mineralization (53.9 vs. 43.4%) and reaction quantum efficiency (i.e., photonic efficiency, 63.3 vs. 50.1 nmol CO2 (mu)mol/photons). UV-C irradiation also led to decreased intermediate concentration in the effluent . compared to UV-A irradiation. These results demonstrated that STC-catalyzed oxidation is enhanced by both increased photon flux and photon energy.

Effect of short LED lamp exposure on wear resistance, residual monomer and degree of conversion for Filtek Z250 and Tetric EvoCeram composites.

PubMed

Kopperud, Hilde M; Johnsen, Gaute F; Lamolle, Sébastien; Kleven, Inger S; Wellendorf, Hanne; Haugen, Håvard J

2013-08-01

The latest LED dental curing devices claim sufficient curing of restorative materials with short curing times. This study evaluates mechanical and chemical properties as a function of curing time of two commercial composite filling materials cured with three different LED lamps. The composites were Filtek Z250 (3M ESPE) and Tetric EvoCeram (Ivoclar Vivadent) and the LED curing devices were bluephase 16i (Ivoclar Vivadent), L.E.Demetron II (Kerr) and Mini L.E.D. (Satelec). Control samples were cured with a QTH-lamp (VCL 400, Kerr). The wear resistance after simulated tooth brushing, degree of conversion, curing depth, and amounts of residual monomers were measured after different curing times. The results of this study show that short curing time with high-intensity LEDs may influence the bulk properties of the materials, resulting in lower curing depth and increased residual monomer content. The measured surface properties of the materials, degree of conversion and wear resistance, were not affected by short curing times to the same extent. This study demonstrates that reduced exposure time with high intensity LEDs can result in composite restorations with inferior curing depth and increased leaching of monomers. Dentists are recommended to use sufficient curing times even with high intensity LEDs to ensure adequate curing and minimize the risk of monomer leaching. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Discharge lamp technologies

NASA Technical Reports Server (NTRS)

Dakin, James

1994-01-01

This talk is an overview of discharge lamp technology commonly employed in general lighting, with emphasis on issues pertinent to lighting for plant growth. Since the audience is primarily from the plant growth community, and this begins the light source part of the program, we will start with a brief description of the discharge lamps. Challenges of economics and of thermal management make lamp efficiency a prime concern in controlled environment agriculture, so we will emphasize science considerations relating to discharge lamp efficiency. We will then look at the spectra and ratings of some representative lighting products, and conclude with a discussion of technological advances.

Novel wafer stepper with violet LED light source

NASA Astrophysics Data System (ADS)

Ting, Yung-Chiang; Shy, Shyi-Long

2014-03-01

Novel wafer stepper by using contact or proximity printing will be developed, using violet LED light source to replace Hg Arc. lamp or laser. Mirror, filter and condenser lens for Hg Arc. Lamp or laser and reduction lens for projection printing can be discarded. Reliability and manufacturing cost of wafer stepper can be improved. Exposure result by using IP3600 resist and wafer stepper with violet LED light source (wave-length 360nm to 410 nm) will be obtained. This novel wafer stepper can be used for 3DIC, MEMS and bio-chip lithography application by using thin and thick resist with sub-micron to 100 micron thickness.

Recent Advances in Lighting Science

NASA Astrophysics Data System (ADS)

Lapatovich, Walter P.

2004-10-01

Lighting is a global industry supplying a wide array of devices and systems that emit light ranging from incandescent lamps to light emitting diodes to electric discharge lamps. Electric discharge lamps are the most familiar plasma devices to most people. This work focuses on plasma light sources, some advances in this area and recent trends. Plasma light sources fall into two broad categories, namely low pressure and high pressure. The low-pressure lamps operate in the range of 40 to 500 Pa while the high-pressure lamps operate in the range of 0.1 to 15 MPa. The corresponding electron temperatures are about 1eV and 0.5 eV for the low and high-pressure lamps respectively. High-pressure lamps are treated under the assumption of local thermodynamic equilibrium wherein the gas temperature is equilibrated with the electron temperature. They are often called high intensity discharge lamps because of their intrinsically high radiance. Within these two broad categories are many subgroups, perhaps the most important being mercury and non-mercury containing lamps. An example of a low pressure, mercury-containing lamp is the ubiquitous fluorescent lamp. Attempts to improve the efficiency of these lamps center around inductive excitation techniques and two-photon phosphor development. The plasma research on mercury-free low-pressure lamps is focused on finding substitutes for a mercury-rare gas discharge. Several ultraviolet emitting candidates have been explored which emit both UV and visible. Longer wavelength UV is of interest because of the parallel development of phosphors mated with LED excitation wavelengths around 380nm. Several examples will be discussed. There have been major advances in high intensity discharge lamps with and without mercury. Mercury containing metal halide lamps are now being fabricated from translucent ceramic envelopes instead of the conventional vitreous silica. The higher temperature tolerant envelope materials permit using discharges in vapors hitherto unacceptable because of chemical reactions. Temperature driven chemical reactions (which affect lamp life, starting and stability) are better understood. Lamps are better designed with finite element thermal modeling and thermodynamic computational tools. Improved understanding of molecular processes in the energy transport within the plasma has opened possibilities for new types of light sources relying heavily on molecular emission. Examples of lamps containing sulfur, indium, thallium and rare earth halides will be discussed. General trends in plasma based light source have been towards lower wattage, directed visible output, high quality visible output, longer life and mercury-free lamps. Consumer demand for high tech, high performance lighting devices has broadened the use of HID lamps in automobiles, video/data display and medical/technical applications. Short arc gap lamps (1mm) with a luminance exceeding that of the sun's surface (1600cd/mm2 -as observed from earth), and operating with extreme line broadening lead the video projection market. Low wattage HID lamps coupled with tailored optics can direct the light output more precisely leading to reduced light pollution and better system throughput. Tailoring of the driving electrical waveforms have enabled stable operation, controlled the effects of species segregation and improved lamp life and performance.

[Functional state of the visual analyzer in the conditions of the use of traditional and LED light sources].

PubMed

Kaptsov, V A; Sosunov, N N; Shishchenko, I I; Viktorov, V S; Tulushev, V N; Deynego, V N; Bukhareva, E A; Murashova, M A; Shishchenko, A A

2014-01-01

There was performed the experimental work on the study of the possibility of the application of LED lighting (LED light sources) in rail transport for traffic safety in related professions. Results of 4 series of studies involving 10 volunteers for the study and a comparative evaluation of the functional state of the visual analyzer, the general functional state and mental capacity under the performing the simulated operator activity in conditions of traditional light sources (incandescent, fluorescent lamp) and the new LED (LED lamp, LED panel) light sources have revealed changes in the negative direction. This was pronounced in a some decrease of functional stability to color discrimination between green and red cone signals, as well as an increase in response time in complex visual--motor response and significant reduction in readiness for emergency action of examinees.

Rapid assessment of lamp spectrum to quantify ecological effects of light at night.

PubMed

Longcore, Travis; Rodríguez, Airam; Witherington, Blair; Penniman, Jay F; Herf, Lorna; Herf, Michael

2018-06-12

For many decades, the spectral composition of lighting was determined by the type of lamp, which also influenced potential effects of outdoor lights on species and ecosystems. Light-emitting diode (LED) lamps have dramatically increased the range of spectral profiles of light that is economically viable for outdoor lighting. Because of the array of choices, it is necessary to develop methods to predict the effects of different spectral profiles without conducting field studies, especially because older lighting systems are being replaced rapidly. We describe an approach to predict responses of exemplar organisms and groups to lamps of different spectral output by calculating an index based on action spectra from behavioral or visual characteristics of organisms and lamp spectral irradiance. We calculate relative response indices for a range of lamp types and light sources and develop an index that identifies lamps that minimize predicted effects as measured by ecological, physiological, and astronomical indices. Using these assessment metrics, filtered yellow-green and amber LEDs are predicted to have lower effects on wildlife than high pressure sodium lamps, while blue-rich lighting (e.g., K ≥ 2200) would have greater effects. The approach can be updated with new information about behavioral or visual responses of organisms and used to test new lighting products based on spectrum. Together with control of intensity, direction, and duration, the approach can be used to predict and then minimize the adverse effects of lighting and can be tailored to individual species or taxonomic groups. © 2018 Wiley Periodicals, Inc.

Potential environmental impacts from the metals in incandescent, compact fluorescent lamp (CFL), and light-emitting diode (LED) bulbs.

PubMed

Lim, Seong-Rin; Kang, Daniel; Ogunseitan, Oladele A; Schoenung, Julie M

2013-01-15

Artificial lighting systems are transitioning from incandescent to compact fluorescent lamp (CFL) and light-emitting diode (LED) bulbs in response to the U.S. Energy Independence and Security Act and the EU Ecodesign Directive, which leads to energy savings and reduced greenhouse gas emissions. Although CFLs and LEDs are more energy-efficient than incandescent bulbs, they require more metal-containing components. There is uncertainty about the potential environmental impacts of these components and whether special provisions must be made for their disposal at the end of useful life. Therefore, the objective of this study is to analyze the resource depletion and toxicity potentials from the metals in incandescent, CFL, and LED bulbs to complement the development of sustainable energy policy. We assessed the potentials by examining whether the lighting products are to be categorized as hazardous waste under existing U.S. federal and California state regulations and by applying life cycle impact-based and hazard-based assessment methods (note that "life cycle impact-based method" does not mean a general life cycle assessment (LCA) but rather the elements in LCA used to quantify toxicity potentials). We discovered that both CFL and LED bulbs are categorized as hazardous, due to excessive levels of lead (Pb) leachability (132 and 44 mg/L, respectively; regulatory limit: 5) and the high contents of copper (111,000 and 31,600 mg/kg, respectively; limit: 2500), lead (3860 mg/kg for the CFL bulb; limit: 1000), and zinc (34,500 mg/kg for the CFL bulb; limit: 5000), while the incandescent bulb is not hazardous (note that the results for CFL bulbs excluded mercury vapor not captured during sample preparation). The CFLs and LEDs have higher resource depletion and toxicity potentials than the incandescent bulb due primarily to their high aluminum, copper, gold, lead, silver, and zinc. Comparing the bulbs on an equivalent quantity basis with respect to the expected lifetimes of the bulbs, the CFLs and LEDs have 3-26 and 2-3 times higher potential impacts than the incandescent bulb, respectively. We conclude that in addition to enhancing energy efficiency, conservation and sustainability policies should focus on the development of technologies that reduce the content of hazardous and rare metals in lighting products without compromising their performance and useful lifespan.

Quenching of unincorporated amplification signal reporters in reverse-transcription loop-mediated isothermal amplification enabling bright, single-step, closed-tube, and multiplexed detection of RNA viruses

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

Ball, Cameron S.; Light, Yooli K.; Koh, Chung -Yan

Reverse-transcription-loop-mediated isothermal amplification (RT-LAMP) has frequently been proposed as an enabling technology for simplified diagnostic tests for RNA viruses. However, common detection techniques used for LAMP and RT-LAMP have drawbacks, including poor discrimination capability, inability to multiplex targets, high rates of false positives, and (in some cases) the requirement of opening reaction tubes postamplification. Here, we present a simple technique that allows closed-tube, target-specific detection, based on inclusion of a dye-labeled primer that is incorporated into a target-specific amplicon if the target is present. A short, complementary quencher hybridizes to unincorporated primer upon cooling down at the end of themore » reaction, thereby quenching fluorescence of any unincorporated primer. Our technique, which we term QUASR (for quenching of unincorporated amplification signal reporters, read “quasar”), does not significantly reduce the amplification efficiency or sensitivity of RT-LAMP. Equipped with a simple LED excitation source and a colored plastic gel filter, the naked eye or a camera can easily discriminate between positive and negative QUASR reactions, which produce a difference in signal of approximately 10:1 without background subtraction. We demonstrate that QUASR detection is compatible with complex sample matrices such as human blood, using a novel LAMP primer set for bacteriophage MS2 (a model RNA virus particle). As a result, we demonstrate single-tube duplex detection of West Nile virus (WNV) and chikungunya virus (CHIKV) RNA.« less

Quenching of unincorporated amplification signal reporters in reverse-transcription loop-mediated isothermal amplification enabling bright, single-step, closed-tube, and multiplexed detection of RNA viruses

DOE PAGES

Ball, Cameron S.; Light, Yooli K.; Koh, Chung -Yan; ...

2016-03-16

Reverse-transcription-loop-mediated isothermal amplification (RT-LAMP) has frequently been proposed as an enabling technology for simplified diagnostic tests for RNA viruses. However, common detection techniques used for LAMP and RT-LAMP have drawbacks, including poor discrimination capability, inability to multiplex targets, high rates of false positives, and (in some cases) the requirement of opening reaction tubes postamplification. Here, we present a simple technique that allows closed-tube, target-specific detection, based on inclusion of a dye-labeled primer that is incorporated into a target-specific amplicon if the target is present. A short, complementary quencher hybridizes to unincorporated primer upon cooling down at the end of themore » reaction, thereby quenching fluorescence of any unincorporated primer. Our technique, which we term QUASR (for quenching of unincorporated amplification signal reporters, read “quasar”), does not significantly reduce the amplification efficiency or sensitivity of RT-LAMP. Equipped with a simple LED excitation source and a colored plastic gel filter, the naked eye or a camera can easily discriminate between positive and negative QUASR reactions, which produce a difference in signal of approximately 10:1 without background subtraction. We demonstrate that QUASR detection is compatible with complex sample matrices such as human blood, using a novel LAMP primer set for bacteriophage MS2 (a model RNA virus particle). As a result, we demonstrate single-tube duplex detection of West Nile virus (WNV) and chikungunya virus (CHIKV) RNA.« less

Numerical study on xenon positive column discharges of mercury-free lamp

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

Ouyang, Jiting; He, Feng; Miao, Jinsong

2007-02-15

In this paper, the numerical study has been performed on the xenon positive column discharges of mercury-free fluorescent lamp. The plasma discharge characteristics are analyzed by numerical simulation based on two-dimensional fluid model. The effects of cell geometry, such as the dielectric layer, the electrode width, the electrode gap, and the cell height, and the filling gas including the pressure and the xenon percentage are investigated in terms of discharge current and discharge efficiency. The results show that a long transient positive column will form in the xenon lamp when applying ac sinusoidal power and the lamp can operate inmore » a large range of voltage and frequency. The front dielectric layer of the cell plays an important role in the xenon lamp while the back layer has little effect. The ratio of electrode gap to cell height should be large to achieve a long positive column xenon lamp and higher efficiency. Increase of pressure or xenon concentration results in an increase of discharge efficiency and voltage. The discussions will be helpful for the design of commercial xenon lamp cells.« less

LED lamp or bulb with remote phosphor and diffuser configuration with enhanced scattering properties

DOEpatents

Tong, Tao; Le Toquin, Ronan; Keller, Bernd; Tarsa, Eric; Youmans, Mark; Lowes, Theodore; Medendorp, Jr., Nicholas W; Van De Ven, Antony; Negley, Gerald

2014-11-11

An LED lamp or bulb is disclosed that comprises a light source, a heat sink structure and an optical cavity. The optical cavity comprises a phosphor carrier having a conversions material and arranged over an opening to the cavity. The phosphor carrier comprises a thermally conductive transparent material and is thermally coupled to the heat sink structure. An LED based light source is mounted in the optical cavity remote to the phosphor carrier with light from the light source passing through the phosphor carrier. A diffuser dome is included that is mounted over the optical cavity, with light from the optical cavity passing through the diffuser dome. The properties of the diffuser, such as geometry, scattering properties of the scattering layer, surface roughness or smoothness, and spatial distribution of the scattering layer properties may be used to control various lamp properties such as color uniformity and light intensity distribution as a function of viewing angle.

46 CFR 167.40-25 - Signaling lamp.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Signaling lamp. 167.40-25 Section 167.40-25 Shipping... Certain Equipment Requirements § 167.40-25 Signaling lamp. Nautical school ships of over 150 gross tons shall be equipped with an efficient signaling lamp. This lamp shall be permanently fixed above the...

46 CFR 167.40-25 - Signaling lamp.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Signaling lamp. 167.40-25 Section 167.40-25 Shipping... Certain Equipment Requirements § 167.40-25 Signaling lamp. Nautical school ships of over 150 gross tons shall be equipped with an efficient signaling lamp. This lamp shall be permanently fixed above the...

46 CFR 167.40-25 - Signaling lamp.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Signaling lamp. 167.40-25 Section 167.40-25 Shipping... Certain Equipment Requirements § 167.40-25 Signaling lamp. Nautical school ships of over 150 gross tons shall be equipped with an efficient signaling lamp. This lamp shall be permanently fixed above the...

46 CFR 167.40-25 - Signaling lamp.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Signaling lamp. 167.40-25 Section 167.40-25 Shipping... Certain Equipment Requirements § 167.40-25 Signaling lamp. Nautical school ships of over 150 gross tons shall be equipped with an efficient signaling lamp. This lamp shall be permanently fixed above the...

46 CFR 167.40-25 - Signaling lamp.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Signaling lamp. 167.40-25 Section 167.40-25 Shipping... Certain Equipment Requirements § 167.40-25 Signaling lamp. Nautical school ships of over 150 gross tons shall be equipped with an efficient signaling lamp. This lamp shall be permanently fixed above the...

Guidelines for application of fluorescent lamps in high-performance avionic backlight systems

NASA Astrophysics Data System (ADS)

Syroid, Daniel D.

1997-07-01

Fluorescent lamps have proven to be well suited for use in high performance avionic backlight systems as demonstrated by numerous production applications for both commercial and military cockpit displays. Cockpit display applications include: Boeing 777, new 737s, F-15, F-16, F-18, F-22, C- 130, Navy P3, NASA Space Shuttle and many others. Fluorescent lamp based backlights provide high luminance, high lumen efficiency, precision chromaticity and long life for avionic active matrix liquid crystal display applications. Lamps have been produced in many sizes and shapes. Lamp diameters range from 2.6 mm to over 20 mm and lengths for the larger diameter lamps range to over one meter. Highly convoluted serpentine lamp configurations are common as are both hot and cold cathode electrode designs. This paper will review fluorescent lamp operating principles, discuss typical requirements for avionic grade lamps, compare avionic and laptop backlight designs and provide guidelines for the proper application of lamps and performance choices that must be made to attain optimum system performance considering high luminance output, system efficiency, dimming range and cost.

Wired.

ERIC Educational Resources Information Center

Conklin, Aaron R.

1998-01-01

Discusses technology's impact on scoreboard design: the development of the light-emitting diode (LED) display. How the LED system works is explained, as are the advantages and disadvantages of LED compared with incandescent lamp boards. Final comments address deciding on materials for scoreboard casings. (GR)

Green-light supplementation for enhanced lettuce growth under red- and blue-light-emitting diodes

NASA Technical Reports Server (NTRS)

Kim, Hyeon-Hye; Goins, Gregory D.; Wheeler, Raymond M.; Sager, John C.

2004-01-01

Plants will be an important component of future long-term space missions. Lighting systems for growing plants will need to be lightweight, reliable, and durable, and light-emitting diodes (LEDs) have these characteristics. Previous studies demonstrated that the combination of red and blue light was an effective light source for several crops. Yet the appearance of plants under red and blue lighting is purplish gray making visual assessment of any problems difficult. The addition of green light would make the plant leave appear green and normal similar to a natural setting under white light and may also offer a psychological benefit to the crew. Green supplemental lighting could also offer benefits, since green light can better penetrate the plant canopy and potentially increase plant growth by increasing photosynthesis from the leaves in the lower canopy. In this study, four light sources were tested: 1) red and blue LEDs (RB), 2) red and blue LEDs with green fluorescent lamps (RGB), 3) green fluorescent lamps (GF), and 4) cool-white fluorescent lamps (CWF), that provided 0%, 24%, 86%, and 51% of the total PPF in the green region of the spectrum, respectively. The addition of 24% green light (500 to 600 nm) to red and blue LEDs (RGB treatment) enhanced plant growth. The RGB treatment plants produced more biomass than the plants grown under the cool-white fluorescent lamps (CWF treatment), a commonly tested light source used as a broad-spectrum control.

New closed tube loop mediated isothermal amplification assay for prevention of product cross-contamination

PubMed Central

Karthik, K.; Rathore, Rajesh; Thomas, Prasad; Arun, T.R.; Viswas, K.N.; Dhama, Kuldeep; Agarwal, R.K.

2014-01-01

Loop mediated isothermal amplification (LAMP) assay, a promising diagnostic test, has been developed for detection of different pathogens of human as well as animals. Various positive points support its use as a field level test but the major problem is product cross contamination leading to false positive results. Different methods were adopted by various researchers to control this false positive amplification due to cross contamination but all have their own advantages and disadvantages. A new closed tube LAMP assay based on agar dye capsule was developed in the present study and this technique has some advantages over the other closed tube technique.•Agar at the concentration of 1.5% was used to sandwich SYBR green dye I with the aid of intradermal syringe. This agar dye capsule was placed over the LAMP reaction mixture before it was amplified.•To eliminate the hazardous nature of Ultra Violet (UV) light during result visualization of LAMP products, the present study demonstrates the use of Light Emitting Diode (LED) lights for result visualization.•LAMP was carried out for Brucella species detection using this modified techniques yielding good results without any cross contamination and LED showed similar fluorescence compared to UV. PMID:26150945

New closed tube loop mediated isothermal amplification assay for prevention of product cross-contamination.

PubMed

Karthik, K; Rathore, Rajesh; Thomas, Prasad; Arun, T R; Viswas, K N; Dhama, Kuldeep; Agarwal, R K

2014-01-01

Loop mediated isothermal amplification (LAMP) assay, a promising diagnostic test, has been developed for detection of different pathogens of human as well as animals. Various positive points support its use as a field level test but the major problem is product cross contamination leading to false positive results. Different methods were adopted by various researchers to control this false positive amplification due to cross contamination but all have their own advantages and disadvantages. A new closed tube LAMP assay based on agar dye capsule was developed in the present study and this technique has some advantages over the other closed tube technique.•Agar at the concentration of 1.5% was used to sandwich SYBR green dye I with the aid of intradermal syringe. This agar dye capsule was placed over the LAMP reaction mixture before it was amplified.•To eliminate the hazardous nature of Ultra Violet (UV) light during result visualization of LAMP products, the present study demonstrates the use of Light Emitting Diode (LED) lights for result visualization.•LAMP was carried out for Brucella species detection using this modified techniques yielding good results without any cross contamination and LED showed similar fluorescence compared to UV.

Deep ultraviolet light-emitting and laser diodes

NASA Astrophysics Data System (ADS)

Khan, Asif; Asif, Fatima; Muhtadi, Sakib

2016-02-01

Nearly all the air-water purification/polymer curing systems and bio-medical instruments require 250-300 nm wavelength ultraviolet light for which mercury lamps are primarily used. As a potential replacement for these hazardous mercury lamps, several global research teams are developing AlGaN based Deep Ultraviolet (DUV) light emitting diodes (LEDs) and DUV LED Lamps and Laser Diodes over Sapphire and AlN substrates. In this paper, we review the current research focus and the latest device results. In addition to the current results we also discuss a new quasipseudomorphic device design approach. This approach which is much easier to integrate in a commercial production setting was successfully used to demonstrate UVC devices on Sapphire substrates with performance levels equal to or better than the conventional relaxed device designs.

Apparatus for Teaching Physics.

ERIC Educational Resources Information Center

Gottlieb, Herbert H., Ed.

1981-01-01

Describes: (1) a seven-segment LED display successfully used as an "illuminated" object for introductory optics experiments and advantages for its use; (2) a series/parallel circuit demonstration especially useful in introductory courses for nonmajors; and (3) a method for igniting a sodium arc lamp with an incandescent lamp. (JN)

Synthesis and photoluminescence in Yb doped cerium phosphate CePO4

NASA Astrophysics Data System (ADS)

Bhonsule, S. U.; Wankhede, S. P.; Moharil, S. V.

2018-05-01

This paper presents the preparation of CePO4 and Yb doped CePO4 using simple solid state reaction method. PL measurements indicated significant energy transfer from Ce3+ to Yb3+ ions. Further evidence of energy transfer was provided by analysis of Luminescence Decay measurements. Energy transfer efficiency of 50% was obtained for 5%Yb doping. Energy transfer from Ce3+ to Yb3+ ions takes place by Cooperative energy transfer mechanism. Such phosphors can be used in white LED's, Lasers and energy saving fluorescent lamps.

Monte Carlo treatment of resonance-radiation imprisonment in fluorescent lamps—revisited

NASA Astrophysics Data System (ADS)

Anderson, James B.

2016-12-01

We reported in 1985 a Monte Carlo treatment of the imprisonment of the 253.7 nm resonance radiation from mercury in the mercury-argon discharge of fluorescent lamps. The calculated spectra of the emitted radiation were found in good agreement with measured spectra. The addition of the isotope mercury-196 to natural mercury was found, also in agreement with experiments, to increase lamp efficiency. In this paper we report the extension of the earlier work with increased accuracy, analysis of photon exit-time distributions, recycling of energy released in quenching, analysis of dynamic similarity for different lamp sizes, variation of Mrozowski transfer rates, prediction and analysis of the hyperfine ultra-violet spectra, and optimization of tailored mercury isotope mixtures for increased lamp efficiency. The spectra were found insensitive to the extent of quenching and recycling. The optimized mixtures were found to increase efficiencies by as much as 5% for several lamp configurations. Optimization without increasing the mercury-196 fraction was found to increase efficiencies by nearly 1% for several configurations.

[A new non-contact method based on relative spectral intensity for determining junction temperature of LED].

PubMed

Qiu, Xi-Zhen; Zhang, Fang-Hui

2013-01-01

The high-power white LED was prepared based on the high thermal conductivity aluminum, blue chips and YAG phosphor. By studying the spectral of different junction temperature, we found that the radiation spectrum of white LED has a minimum at 485 nm. The radiation intensity at this wavelength and the junction temperature show a good linear relationship. The LED junction temperature was measured based on the formula of relative spectral intensity and junction temperature. The result measured by radiation intensity method was compared with the forward voltage method and spectral method. The experiment results reveal that the junction temperature measured by this method was no more than 2 degrees C compared with the forward voltage method. It maintains the accuracy of the forward voltage method and overcomes the small spectral shift of spectral method, which brings the shortcoming on the results. It also had the advantages of practical, efficient and intuitive, noncontact measurement, and non-destruction to the lamp structure.

Improved LED backlight with unique color and intensity control and NVIS capability

NASA Astrophysics Data System (ADS)

Herman, Robert; Zagar, Pete; Ulijasz, Ted; Hansen, Hans C.; Ellner, Fred

2006-05-01

Currently deployed conventional flat panel AMLCD displays employ fluorescent lamp backlights to achieve the required lighting levels for cockpits in high performance aircraft. Advances have been made in backlighting technology by replacing fluorescent lamps with high performance LEDs. However, these new LED-based backlights are lacking in control of color and luminance intensity especially when related to NVIS requirements in a cockpit. This paper describes a unique integration of LED, electronic, and optical components to meet the requirements of high performance aircraft over their extreme range of operating environments. The LED-based backlight utilizes state-of-art components to enable daylight, night, and NVIS requirements to be implemented in a simple cost-effective package. The performance results presented highlight the advantages of this new design when compared to currently available backlighting designs. Techniques as described in section 2 of this paper are covered under patent application to the US and International Patent Offices.

Photochemical methods to assay DNA photocleavage using supercoiled pUC18 DNA and LED or xenon arc lamp excitation.

PubMed

Prussin, Aaron J; Zigler, David F; Jain, Avijita; Brown, Jared R; Winkel, Brenda S J; Brewer, Karen J

2008-04-01

Methods for the study of DNA photocleavage are illustrated using a mixed-metal supramolecular complex [{(bpy)(2)Ru(dpp)}(2)RhCl(2)]Cl(5). The methods use supercoiled pUC18 plasmid as a DNA probe and either filtered light from a xenon arc lamp source or monochromatic light from a newly designed, high-intensity light-emitting diode (LED) array. Detailed methods for performing the photochemical experiments and analysis of the DNA photoproduct are delineated. Detailed methods are also given for building an LED array to be used for DNA photolysis experiments. The Xe arc source has a broad spectral range and high light flux. The LEDs have a high-intensity, nearly monochromatic output. Arrays of LEDs have the advantage of allowing tunable, accurate output to multiple samples for high-throughput photochemistry experiments at relatively low cost.

Development of AlGaN-based deep-ultraviolet (DUV) LEDs focusing on the fluorine resin encapsulation and the prospect of the practical applications

NASA Astrophysics Data System (ADS)

Hirano, Akira; Nagasawa, Yosuke; Ippommatsu, Masamichi; Aosaki, Ko; Honda, Yoshio; Amano, Hiroshi; Akasaki, Isamu

2016-09-01

AlGaN-based LEDs are expected to be useful for sterilization, deodorization, photochemical applications such as UV curing and UV printing, medical applications such as phototherapy, and sensing. Today, it has become clear that efficient AlGaN-based LED dies are producible between 355 and 250 nm with an external quantum efficiency (EQE) of 3% on flat sapphire. These dies were realized on flat sapphire without using a special technique, i.e., reduction in threading dislocation density or light extraction enhancement techniques such as the use of a photonic crystal or a patterned sapphire substrate. Despite the limited light extraction efficiency of about 8% owing to light absorption at a thick p-GaN contact layer, high EQEs of approximately 6% has been reproducible between 300 and 280 nm without using special techniques. Moreover, an EQE of 3.9% has been shown at 271 nm, despite the smaller current injection efficiency (CIE). The high EQEs are thought to correspond to the high internal quantum efficiency (IQE), indicating a small room for improving IQE. Accordingly, resin encapsulation on a simple submount is strongly desired. Recently, we have succeeded in demonstrating fluorine resin encapsulation on a ceramic sheet (chip-on-board, COB) that is massproducible. Furthermore, the molecular structure of a resin with a durability of more than 10,000 h is explained in this paper from the photochemical viewpoint. Thus, the key technologies of AlGaN-based DUV-LEDs having an EQE of 10% within a reasonable production cost have been established. The achieved efficiency makes AlGaN-based DUVLEDs comparable to high-pressure mercury lamps.

Effects of ultraviolet light emitting diodes (LEDs) on microbial and enzyme inactivation of apple juice.

PubMed

Akgün, Merve Pelvan; Ünlütürk, Sevcan

2017-11-02

In this study, the effects of Ultraviolet light-emitting diodes (UV-LEDs) on the inactivation of E. coli K12 (ATCC 25253), an indicator organism of E. coli O157:H7, and polyphneoloxidase (PPO) in cloudy apple juice (CAJ) were investigated. The clear (AJ) and cloudy apple juice were exposed to UV rays for 40min by using a UV device composed of four UV-LEDs with peak emissions at 254 and 280nm and coupled emissions as follows: 254/365, 254/405, 280/365, 280/405 and 254/280/365/405nm. UV-LEDs at 254nm achieved 1.6±0.1 log 10 CFU/mL inactivation of E. coli K12 at UV dose of 707.2mJ/cm 2 . The highest inactivation of E. coli K12 (2.0±0.1log 10 CFU/mL and 2.0±0.4log 10 CFU/mL) was achieved when the cloudy apple juice was treated with both 280nm and 280/365nm UV-LEDs. For clear apple juice the highest inactivation 4.4log 10 CFU/mL obtained for E. coli K12 was achieved using 4 lamps emitting light at 280nm for 40min exposure time. For the same treatment time, the experiments using a combination of lamps emitting light at 280 and 365nm (2lamp/2lamp) were resulted in 3.9±0.2log 10 CFU/mL reductions. UV-A and UV-C rays in combination showed a better inactivation effect on PPO than UV-C rays used separately. Residual activity of PPO in CAJ was reduced to 32.58% when treated with UV-LED in combination of UV-C (280nm) and UV-A (365nm) rays. Additionally, the total color change (ΔE) of CAJ subjected to combined UV-LED irradiation at 280/365nm was the lowest compared to other studied processing conditions. This study provides key implications for the future application of UV-LEDs to fruit juice pasteurization. Copyright © 2017 Elsevier B.V. All rights reserved.

Improving spinach, radish, and lettuce growth under red light-emitting diodes (LEDs) with blue light supplementation

NASA Technical Reports Server (NTRS)

Yorio, N. C.; Goins, G. D.; Kagie, H. R.; Wheeler, R. M.; Sager, J. C.

2001-01-01

Radish (Raphanus sativus L. cv. Cherriette), lettuce (Lactuca sativa L. cv. Waldmann's Green), and spinach (Spinacea oleracea L. cv. Nordic IV) plants were grown under 660-nm red light-emitting diodes (LEDs) and were compared at equal photosynthetic photon flux (PPF) with either plants grown under cool-white fluorescent lamps (CWF) or red LEDs supplemented with 10% (30 micromoles m-2 s-1) blue light (400-500 nm) from blue fluorescent (BF) lamps. At 21 days after planting (DAP), leaf photosynthetic rates and stomatal conductance were greater for plants grown under CWF light than for those grown under red LEDs, with or without supplemental blue light. At harvest (21 DAP), total dry-weight accumulation was significantly lower for all species tested when grown under red LEDs alone than when grown under CWF light or red LEDs + 10% BF light. Moreover, total dry weight for radish and spinach was significantly lower under red LEDs + 10% BF than under CWF light, suggesting that addition of blue light to the red LEDs was still insufficient for achieving maximal growth for these crops.

Effects of artificial lighting on the detection of plant stress with spectral reflectance remote sensing in bioregenerative life support systems

NASA Astrophysics Data System (ADS)

Schuerger, Andrew C.; Richards, Jeffrey T.

2006-09-01

Plant-based life support systems that utilize bioregenerative technologies have been proposed for long-term human missions to both the Moon and Mars. Bioregenerative life support systems will utilize higher plants to regenerate oxygen, water, and edible biomass for crews, and are likely to significantly lower the ‘equivalent system mass’ of crewed vehicles. As part of an ongoing effort to begin the development of an automatic remote sensing system to monitor plant health in bioregenerative life support modules, we tested the efficacy of seven artificial illumination sources on the remote detection of plant stresses. A cohort of pepper plants (Capsicum annuum L.) were grown 42 days at 25 °C, 70% relative humidity, and 300 μmol m-2 s-1 of photosynthetically active radiation (PAR; from 400 to 700 nm). Plants were grown under nutritional stresses induced by irrigating subsets of the plants with 100, 50, 25, or 10% of a standard nutrient solution. Reflectance spectra of the healthy and stressed plants were collected under seven artificial lamps including two tungsten halogen lamps, plus high pressure sodium, metal halide, fluorescent, microwave, and red/blue light emitting diode (LED) sources. Results indicated that several common algorithms used to estimate biomass and leaf chlorophyll content were effective in predicting plant stress under all seven illumination sources. However, the two types of tungsten halogen lamps and the microwave illumination source yielded linear models with the highest residuals and thus the highest predictive capabilities of all lamps tested. The illumination sources with the least predictive capabilities were the red/blue LEDs and fluorescent lamps. Although the red/blue LEDs yielded the lowest residuals for linear models derived from the remote sensing data, the LED arrays used in these experiments were optimized for plant productivity and not the collection of remote sensing data. Thus, we propose that if adjusted to optimize the collectio n of remote sensing information from plants, LEDs remain the best candidates for illumination sources for monitoring plant stresses in bioregenerative life support systems.

Effect of radiation light characteristics on surface hardness of paint-on resin for shade modification.

PubMed

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

2005-12-01

The purpose of this study was to investigate the effect of radiation light characteristics--of different types of clinical light-curing unit--on polymerization efficiency, as determined by the surface hardness of light-cured paint-on resins. Four shades of paint-on resin for shade modification of restorative resins were used. Materials were cured using one laboratory and three clinical light-curing units with different light sources, namely tungsten-halogen, LED, plasma arc, and xenon flash lamps. Knoop hardness measurements were taken at both the top and bottom surfaces of the specimens to assess the mechanical properties and degree of polymerization. Both LED and plasma arc light units caused significantly poorer surface hardness than the halogen and laboratory xenon lights. In addition, the transparent shade was more sensitive to surface hardness than other chromatic shades. Our results indicated that the polymerization efficiency of paint-on resin was significantly influenced by the radiation light characteristics of clinical light-curing units.

Innovations in LED lighting for reduced-ESM crop production in space

NASA Astrophysics Data System (ADS)

Massa, Gioia; Mitchell, Cary; Bourget, C. Michael; Morrow, Robert

In controlled-environment crop production such as will be practiced at the lunar outpost and Mars base, the single most energy-demanding aspect is electric lighting for plant growth, including energy costs for energizing lamps as well as for removing excess heat. For a variety of reasons, sunlight may not be a viable option as the main source of crop lighting off-Earth and traditional electric lamps for crop lighting have numerous drawbacks for use in a space environment. A collaborative research venture between the Advanced Life Support Crops Group at Purdue University and the Orbital Technologies Corporation (ORBITEC) has led to the development of efficient, reconfigurable LED lighting technologies for crop growth in an ALSS. The light sources use printed-circuit red and blue LEDs, which are individually tunable for a range of photosynthetic photon fluxes and photomorphogenic plant responses. Initial lighting arrays have LEDs that can be energized from the bottom upward when deployed in a vertical, intracanopy configuration, allowing the illumination to be tailored for stand height throughout the cropping cycle. Preliminary testing with the planophile crop cowpea (Vigna unguiculata L. Walp, breeding line IT87D-941-1), resulted in optimizing internal reflectance of growth compartments by lining walls, floor, and a movable ceiling with white Poly film, as well as by determining optimal planting density and plant positioning. Additionally, these light strips, called "lightsicles", can be configured into an overhead plane of light engines. When intracanopy and overhead-LED-lit cowpea crop production was compared, cowpea plants grown with intracanopy lighting had much greater understory leaf retention and produced more dry biomass per kilowatt-hour of lighting energy than did overhead-lit plants. The efficiency of light capture is reduced in overhead-lit scenarios due to mutual shading of lower leaves by upper leaves in closed canopies leading to premature abscission of lower leaves. One system modification has led to lightsicles of different lengths, allowing a wider array of intracanopy lighting configurations. Another development is an adaptive system in which each light engine can be operated independently, and photodiodes can detect reflectance patterns off of leaves from flashing green LEDs, thereby indicating positions of leaves within the foliar canopy relative to any given light engine on a lightsicle. When this advanced hardware is coupled to tailored software, the reflectance can be used to auto-detect changes in plant growth and adjust the lighting accordingly. These lighting systems have been tested with cowpea, pepper (Capsicum annuum L. cv. Triton) and Lettuce (Lactuca sativa L. cv. Waldmanns Green) with limited testing of other ALS candidate crop species. The versatility of these LED lighting systems will allow energy-efficient light delivery to a wide variety of crops with different growth habits, including planophile, erectophile, and rosette species. This research has been supported by NASA grants NAG5-12686 (NSCORT) and NNK05OA20C (SBIR Phase 1) and NNK06OM01C (SBIR Phase 2).

Fabrication of magnetic Fe@ZnO0.6S0.4 nanocomposite for visible-light-driven photocatalytic inactivation of Escherichia coli

NASA Astrophysics Data System (ADS)

Peng, Ziling; Wu, Dan; Wang, Wei; Tan, Fatang; Ng, Tsz Wai; Chen, Jianguo; Qiao, Xueliang; Wong, Po Keung

2017-02-01

Bacterial inactivation by magnetic photocatalysts has now received growing interests due to the easy separation for recycle and reuse of photocatalysts. In this study, magnetic Fe@ZnO0.6S0.4 photocatalyst was prepared by a facile two-step precipitation method. Multiple techniques such as X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffused reflectance spectra (UV-vis DRS) and vibrating sample magnetometer (VSM) were employed to characterize the structure, morphology and physicochemical properties of the photocatalyst. The as-obtained Fe@ZnO0.6S0.4 possessing magnetic property was easily collected from the reaction system by a magnet. Under white light-emitting-diode (LED) lamp irradiation, Fe@ZnO0.6S0.4 nanocomposite could completely inactivate 7-log of Escherichia coli K-12 within 5 h. More importantly, almost no decrease of photocatalytic efficiency in bacterial inactivation was observed even after five consecutive cycles, demonstrating Fe@ZnO0.6S0.4 exhibited good stability for reuse. The low released rate of Fe2+/Fe3+ and Zn2+ from Fe@ZnO0.6S0.4 composite further indicated the photocatalyst showed low cytotoxicity to bacterium and high stability under LED lamp irradiation. Facile preparation, high photocatalytic efficiency, good stability and reusability, and magnetic recovery property endow Fe@ZnO0.6S0.4 nanocomposite to be a promising photocatalytic material for bacterial inactivation.

The total spectral radiant flux calibration using a spherical spectrometer at National Institute of Metrology China

NASA Astrophysics Data System (ADS)

Zhao, Weiqiang; Liu, Hui; Liu, Jian

2016-11-01

At present day, in the field of lighting the incandescent lamps are phasing out. The solid state lighting products, i.e. LED, and the related market are developing very fast in China for its promising application, due to the energy-saving and the colorful features. For the quality control and the commercial trade purpose, it is highly necessary to measure the optical parameters of LED light sources with a fast, easy and affordable facility. Therefore, more test labs use the spherical spectrometer to measure LED. The quasi- monochrome of LED and the V(lambda) of silicon photodetector mismatch problem is reduced or avoided, because the total spectral radiant flux (TSRF) is measured, and all the optical parameters are calculate from the TSRF. In such a way, the spherical spectrometer calibration requires TSRF standard lamps instead of the traditional total flux standard lamps. National Institute of Metrology China (NIM) has studied and developed the facilities for TSRF measurement and provides related calibration services. This paper shows the TSRF standard lamp calibration procedure using a spherical spectrometer in every-day calibration and its traceable link to the primary SI unit at NIM. The sphere is of 1.5 m diameter, and installed with a spectrometer and a silicon photodetector. It also shows the detail of data process, such as the spectral absorption correction method and the calculation of the result derived from the spectral readings. The TSRF calibration covers the spectra range of 350 nm to 1050 nm, with a measurement uncertainty of 3.6% 1.8% (k=2).

LED lamp

DOEpatents

Galvez, Miguel; Grossman, Kenneth; Betts, David

2013-11-12

There is herein described a lamp for providing white light comprising a plurality of light sources positioned on a substrate. Each of said light sources comprises a blue light emitting diode (LED) and a dome that substantially covers said LED. A first portion of said blue light from said LEDs is transmitted through said domes and a second portion of said blue light is converted into a red light by a first phosphor contained in said domes. A cover is disposed over all of said light sources that transmits at least a portion of said red and blue light emitted by said light sources. The cover contains a second phosphor that emits a yellow light in response to said blue light. The red, blue and yellow light combining to form the white light and the white light having a color rendering index (CRI) of at least about 80.

Detection of Shigella in Milk and Clinical Samples by Magnetic Immunocaptured-Loop-Mediated Isothermal Amplification Assay

PubMed Central

Zhang, Liding; Wei, Qiujiang; Han, Qinqin; Chen, Qiang; Tai, Wenlin; Zhang, Jinyang; Song, Yuzhu; Xia, Xueshan

2018-01-01

Shigella is an important human food-borne zoonosis bacterial pathogen, and can cause clinically severe diarrhea. There is an urgent need to develop a specific, sensitive, and rapid methodology for detection of this pathogen. In this study, loop-mediated isothermal amplification (LAMP) combined with magnetic immunocapture assay (IC-LAMP) was first developed for the detection of Shigella in pure culture, artificial milk, and clinical stool samples. This method exhibited a detection limit of 8.7 CFU/mL. Compared with polymerase chain reaction, IC-LAMP is sensitive, specific, and reliable for monitoring Shigella. Additionally, IC-LAMP is more convenient, efficient, and rapid than ordinary LAMP, as it is more efficiently enriches pathogen cells without extraction of genomic DNA. Under isothermal conditions, the amplification curves and the green fluorescence were detected within 30 min in the presence of genomic DNA template. The overall analysis time was approximately 1 h, including the enrichment and lysis of the bacterial cells, a significantly short detection time. Therefore, the IC-LAMP methodology described here is potentially useful for the efficient detection of Shigella in various samples. PMID:29467730

Influence of curing mode with a LED unit on polymerization contraction kinetics and degree of conversion of dental resin-based materials.

PubMed

Mortier, Eric; Simon, Yorick; Dahoun, Abdelsellam; Gerdolle, David

2009-01-01

The purpose of this study was to evaluate the influence of photopolymerization mode with a light emitting diode (LED) lamp on the curing contraction kinetics and degree of conversion of 3 resin-based restorative materials. The curing contraction kinetics of Admira (ADM), Filtek P60 (P60), and Filtek Flow (FLO) were measured by the glass slide method. The materials were exposed to light from a 1,000 mW/cm-(2) power LED lamp (Elipar Freelight 2) in 3 modes: 2 continuous modes of 20 and 40 seconds (C20 and C40), and 1 exponential mode (E20; 5 seconds of exponential power increase followed by 15 seconds of maximum intensity). The degree of conversion (DC) was measured for each of the materials, and each of the modes by Fourier transformed infra-red spectrometry. P60 had the significantly lowest final contraction and FLO the highest among all light exposure modes. The C20 and C40 modes did not produce any difference in contraction or degree of conversion. The E20 mode led to a significant slowing of contraction speed combined with greater final contraction. Use of a LED lamp (1,000 mW/cm2) in continuous mode reduces the exposure time by half for identical curing shrinkage and degree of conversion.

Fisheye camera method for spatial non-uniformity corrections in luminous flux measurements with integrating spheres

NASA Astrophysics Data System (ADS)

Kokka, Alexander; Pulli, Tomi; Poikonen, Tuomas; Askola, Janne; Ikonen, Erkki

2017-08-01

This paper presents a fisheye camera method for determining spatial non-uniformity corrections in luminous flux measurements with integrating spheres. Using a fisheye camera installed into a port of an integrating sphere, the relative angular intensity distribution of the lamp under test is determined. This angular distribution is used for calculating the spatial non-uniformity correction for the lamp when combined with the spatial responsivity data of the sphere. The method was validated by comparing it to a traditional goniophotometric approach when determining spatial correction factors for 13 LED lamps with different angular spreads. The deviations between the spatial correction factors obtained using the two methods ranged from -0.15 % to 0.15%. The mean magnitude of the deviations was 0.06%. For a typical LED lamp, the expanded uncertainty (k = 2 ) for the spatial non-uniformity correction factor was evaluated to be 0.28%. The fisheye camera method removes the need for goniophotometric measurements in determining spatial non-uniformity corrections, thus resulting in considerable system simplification. Generally, no permanent modifications to existing integrating spheres are required.

Hyperspectral Image-Based Night-Time Vehicle Light Detection Using Spectral Normalization and Distance Mapper for Intelligent Headlight Control.

PubMed

Kim, Heekang; Kwon, Soon; Kim, Sungho

2016-07-08

This paper proposes a vehicle light detection method using a hyperspectral camera instead of a Charge-Coupled Device (CCD) or Complementary metal-Oxide-Semiconductor (CMOS) camera for adaptive car headlamp control. To apply Intelligent Headlight Control (IHC), the vehicle headlights need to be detected. Headlights are comprised from a variety of lighting sources, such as Light Emitting Diodes (LEDs), High-intensity discharge (HID), and halogen lamps. In addition, rear lamps are made of LED and halogen lamp. This paper refers to the recent research in IHC. Some problems exist in the detection of headlights, such as erroneous detection of street lights or sign lights and the reflection plate of ego-car from CCD or CMOS images. To solve these problems, this study uses hyperspectral images because they have hundreds of bands and provide more information than a CCD or CMOS camera. Recent methods to detect headlights used the Spectral Angle Mapper (SAM), Spectral Correlation Mapper (SCM), and Euclidean Distance Mapper (EDM). The experimental results highlight the feasibility of the proposed method in three types of lights (LED, HID, and halogen).

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

Johnstone, Peter; Jacobson, Arne; Mills, Evan

The notion of"productive use" is often invoked in discussions about whether new technologies improve productivity or otherwise enhance commerce in developing-country contexts. It an elusive concept,especially when quantitative measures are sought. Improved and more energy efficient illumination systems for off-gridapplication--the focus of the Lumina Project--provide a case in which a significant productivity benefit can be imagined, given the importance of light to the successful performance of many tasks, and the very low quality of baseline illumination provided by flame-based source. This Research Note summarizes self-reported quantitative and qualitative impacts of switching to LED lighting technology on the prosperity of night-marketmore » business owners and operators. The information was gathered in the context of our 2008 market testing field work in Kenya?s Rift Valley Province, which was performed in the towns of Maai Mahiu and Karagita by Arne Jacobson, Kristen Radecsky, Peter Johnstone, Maina Mumbi, and others. Maai Mahiu is a crossroads town; provision of services to travelers and freight carriers is a primary income source for the residents. In contrast, the primary income for Karagita's residents is from work in the large, factory style flower farms on the eastern shores of Lake Naivasha that specialize in producing cut flowers for export to the European market. According to residents, both towns had populations of 6,000 to 8,000 people in June 2008. We focused on quantifying the economics of fuel-based and LED lighting technology in the context of business use by night market vendors and shop keepers. Our research activities with the business owners and operators included baseline measurement of their fuel-based lighting use, an initial survey, offering for sale data logger equipped rechargeable LED lamps, monitoring the adoption of the LED lamps, and a follow-up survey.« less

Projecting LED product life based on application

NASA Astrophysics Data System (ADS)

Narendran, Nadarajah; Liu, Yi-wei; Mou, Xi; Thotagamuwa, Dinusha R.; Eshwarage, Oshadhi V. Madihe

2016-09-01

LED products have started to displace traditional light sources in many lighting applications. One of the commonly claimed benefits for LED lighting products is their long useful lifetime in applications. Today there are many replacement lamp products using LEDs in the marketplace. Typically, lifetime claims of these replacement lamps are in the 25,000-hour range. According to current industry practice, the time for the LED light output to reach the 70% value is estimated according to IESNA LM-80 and TM-21 procedures and the resulting value is reported as the whole system life. LED products generally experience different thermal environments and switching (on-off cycling) patterns when used in applications. Current industry test methods often do not produce accurate lifetime estimates for LED systems because only one component of the system, namely the LED, is tested under a continuous-on burning condition without switching on and off, and because they estimate for only one failure type, lumen depreciation. The objective of the study presented in this manuscript was to develop a test method that could help predict LED system life in any application by testing the whole LED system, including on-off power cycling with sufficient dwell time, and considering both failure types, catastrophic and parametric. The study results showed for the LED A-lamps tested in this study, both failure types, catastrophic and parametric, exist. The on-off cycling encourages catastrophic failure, and maximum operating temperature influences the lumen depreciation rate and parametric failure time. It was also clear that LED system life is negatively affected by on-off switching, contrary to commonly held belief. In addition, the study results showed that most of the LED systems failed catastrophically much ahead of the LED light output reaching the 70% value. This emphasizes the fact that life testing of LED systems must consider catastrophic failure in addition to lumen depreciation, and the shorter of the two failure modes must be selected as the system life. The results of this study show a shorter time test procedure can be developed to accurately predict LED system life in any application by knowing the LED temperature and the switching cycle.

Feasibility of ultraviolet-light-emitting diodes as an alternative light source for photocatalysis.

PubMed

Levine, Lanfang H; Richards, Jeffrey T; Coutts, Janelle L; Soler, Robert; Maxik, Fred; Wheeler, Raymond M

2011-09-01

The objective of this study was to determine whether ultraviolet-light-emitting diodes (UV-LEDs) could serve as an efficient photon source for heterogeneous photocatalytic oxidation (PCO). An LED module consisting of 12 high-power UV-A (lambda max = 365 nm) LEDs was designed to be interchangeable with a UV-A fluorescent black light blue (BLB) lamp for a bench scale annular reactor packed with silica-titania composite (STC) pellets. Lighting and thermal properties of the module were characterized to assess its uniformity and total irradiance. A forward current (I(F)) of 100 mA delivered an average irradiance of 4.0 mW cm(-2) at a distance of 8 mm, which is equivalent to the maximum output of the BLB, but the irradiance of the LED module was less uniform than that of the BLB. The LED and BLB reactors were tested for the oxidization of ethanol (50 ppm(v)) in a continuous-flow-through mode with 0.94 sec residence time. At the same average irradiance, the UV-A LED reactor resulted in a lower CO2 production rate (19.8 vs. 28.6 nmol L(-1) s(-1)), lower ethanol removal (80% vs. 91%), and lower mineralization efficiency (28% vs. 44%) than the UV-A BLB reactor. Ethanol mineralization was enhanced with the increase of the irradiance at the catalyst surface. This result suggests that reduced ethanol mineralization in the LED reactor relative to the BLB reactor at the same average irradiance could be attributed to the nonuniform irradiance over the photocatalyst, that is, a portion of the catalyst was exposed to less than the average irradiance. The potential of UV-A LEDs may be fully realized by optimizing the light distribution over the catalyst and utilizing their instantaneous "on" and "off" feature for periodic irradiation. Nevertheless, our results also showed that the current UV-A LED module had the same wall plug efficiency (WPE) of 13% as that of the UV-A BLB, demonstrating that UV-A LEDs are a viable photon source both in terms of WPE and PCO efficiency.

Limiting the impact of light pollution on human health, environment and stellar visibility.

PubMed

Falchi, Fabio; Cinzano, Pierantonio; Elvidge, Christopher D; Keith, David M; Haim, Abraham

2011-10-01

Light pollution is one of the most rapidly increasing types of environmental degradation. Its levels have been growing exponentially over the natural nocturnal lighting levels provided by starlight and moonlight. To limit this pollution several effective practices have been defined: the use of shielding on lighting fixture to prevent direct upward light, particularly at low angles above the horizon; no over lighting, i.e. avoid using higher lighting levels than strictly needed for the task, constraining illumination to the area where it is needed and the time it will be used. Nevertheless, even after the best control of the light distribution is reached and when the proper quantity of light is used, some upward light emission remains, due to reflections from the lit surfaces and atmospheric scatter. The environmental impact of this "residual light pollution", cannot be neglected and should be limited too. Here we propose a new way to limit the effects of this residual light pollution on wildlife, human health and stellar visibility. We performed analysis of the spectra of common types of lamps for external use, including the new LEDs. We evaluated their emissions relative to the spectral response functions of human eye photoreceptors, in the photopic, scotopic and the 'meltopic' melatonin suppressing bands. We found that the amount of pollution is strongly dependent on the spectral characteristics of the lamps, with the more environmentally friendly lamps being low pressure sodium, followed by high pressure sodium. Most polluting are the lamps with a strong blue emission, like Metal Halide and white LEDs. Migration from the now widely used sodium lamps to white lamps (MH and LEDs) would produce an increase of pollution in the scotopic and melatonin suppression bands of more than five times the present levels, supposing the same photopic installed flux. This increase will exacerbate known and possible unknown effects of light pollution on human health, environment and on visual perception of the Universe by humans. We present quantitative criteria to evaluate the lamps based on their spectral emissions and we suggest regulatory limits for future lighting. Copyright © 2011 Elsevier Ltd. All rights reserved.

Stress Testing of the Philips 60W Replacement Lamp L Prize Entry

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

Poplawski, Michael E.; Ledbetter, Marc R.; Smith, Mark

2012-04-24

The Pacific Northwest National Laboratory, operated by Battelle for the U.S. Department of Energy, worked with Intertek to develop a procedure for stress testing medium screw-base light sources. This procedure, composed of alternating stress cycles and performance evaluation, was used to qualitatively compare and contrast the durability and reliability of the Philips 60W replacement lamp L Prize entry with market-proven compact fluorescent lamps (CFLs) with comparable light output and functionality. The stress cycles applied simultaneous combinations of electrical, thermal, vibration, and humidity stresses of increasing magnitude. Performance evaluations measured relative illuminance, x chromaticity and y chromaticity shifts after each stressmore » cycle. The Philips L Prize entry lamps appear to be appreciably more durable than the incumbent energy-efficient technology, as represented by the evaluated CFLs, and with respect to the applied stresses. Through the course of testing, all 15 CFL samples permanently ceased to function as a result of the applied stresses, while only 1 Philips L Prize entry lamp exhibited a failure, the nature of which was minor, non-destructive, and a consequence of a known (and resolved) subcontractor issue. Given that current CFL technology appears to be moderately mature and no Philips L Prize entry failures could be produced within the stress envelope causing 100 percent failure of the benchmark CFLs, it seems that, in this particular implementation, light-emitting diode (LED) technology would be much more durable in the field than current CFL technology. However, the Philips L Prize entry lamps used for testing were carefully designed and built for the competition, while the benchmark CFLs were mass produced for retail sale—a distinction that should be taken into consideration. Further reliability testing on final production samples would be necessary to judge the extent to which the results of this analysis apply to production versions of the Philips L Prize entry.« less

Efficacy of Inactivation of Human Enteroviruses by Multiple ...

EPA Pesticide Factsheets

Background: Ultraviolet (UV) light has been successfully used for treating a broad suite of pathogens without the concomitant formation of carcinogenic disinfection by-products (DBPs). However, conventional mercury UV lamps have some practical limitations in water treatment applications, such as the inefficiency of energy consumption and more importantly potential mercury contamination upon disposal of the lamps. The recent invention of a novel light-emitting-diodes (LED) device generating germicidal UV wavelengths could eliminate the aforementioned limitations. In this study, we investigated the efficacy of multiple-wavelength UV LEDs for inactivating USEPA contaminant candidate list (CCL) RNA enteroviruses.Methods: Of 12 enterovirus species, serotype representatives of the four human enteric species (enterovirus A-D) such as coxsackievirus A10 (CVA10), echovirus 30 (Echo30), poliovirus 1 (PV1), and enterovirus 70 (EV70) respectively were selected as testing RNA viruses. Bench-scale performance evaluation was conducted using a collimated beam (CB) apparatus with LEDs emitting at 260 nm, 280 nm, and the combination of 260|280 nm together, as well as a monochromatic low-pressure (LP) UV lamp at 254 nm for comparison. The CB tests were performed with mixed stocks of four viruses. Infectious virus concentrations were determined using an integrated cell culture reverse transcriptase quantitative PCR (ICC-RTqPCR).Results: The 260 nm LED was most effective at inactiva

Efficacy of Inactivation of Human Enteroviruses by Multiple ...

EPA Pesticide Factsheets

Ultraviolet (UV) light has been successfully used for treating a broad suite of pathogens without the concomitant formation of carcinogenic disinfection by-products (DBPs). However, conventional mercury UV lamps have some practical limitations in water treatment applications, such as the inefficiency of energy consumption and more importantly potential mercury contamination upon disposal of the lamps. The recent invention of a novel light-emitting-diodes (LED) device generating germicidal UV wavelengths could eliminate the aforementioned limitations. In this study, we investigated the efficacy of multiple-wavelength UV LEDs for inactivating USEPA contaminant candidate list (CCL) RNA enteroviruses. Of 12 enterovirus species, serotype representatives of the four human enteric species (enterovirus A-D) such as coxsackievirus A10 (CVA10), echovirus 30 (Echo30), poliovirus 1 (PV1), and enterovirus 70 (EV70) respectively were selected as testing RNA viruses. Bench-scale performance evaluation was conducted using a collimated beam (CB) apparatus with LEDs emitting at 260 nm, 280 nm, and the combination of 260|280 nm together, as well as a monochromatic low-pressure (LP) UV lamp at 254 nm for comparison. The CB tests were performed with mixed stocks of four viruses. Infectious virus concentrations were determined using an integrated cell culture reverse transcriptase quantitative PCR (ICC-RTqPCR). The 260 nm LED was most effective at inactivating all enteroviruses teste

Growth of GaN nanostructures with polar and semipolar orientations for the fabrication of UV LEDs

NASA Astrophysics Data System (ADS)

Brault, Julien; Damilano, Benjamin; Courville, Aimeric; Leroux, Mathieu; Kahouli, Abdelkarim; Korytov, Maxim; Vennéguès, Philippe; Randazzo, Gaetano; Chenot, Sébastien; Vinter, Borge; De Mierry, Philippe; Massies, Jean; Rosales, Daniel; Bretagnon, Thierry; Gil, Bernard

2014-03-01

(Al,Ga)N light emitting diodes (LEDs), emitting over a large spectral range from 360 nm (GaN) down to 210 nm (AlN), have been successfully fabricated over the last decade. Clear advantages compared to the traditional mercury lamp technology (e.g. compactness, low-power operation, lifetime) have been demonstrated. However, LED efficiencies still need to be improved. The main problems are related to the structural quality and the p-type doping efficiency of (Al,Ga)N. Among the current approaches, GaN nanostructures, which confine carriers along both the growth direction and the growth plane, are seen as a solution for improving the radiative recombination efficiency by strongly reducing the impact of surrounding defects. Our approach, based on a 2D - 3D growth mode transition in molecular beam epitaxy, can lead to the spontaneous formation of GaN nanostructures on (Al,Ga)N over a broad range of Al compositions. Furthermore, the versatility of the process makes it possible to fabricate nanostructures on both (0001) oriented "polar" and (11 2 2) oriented "semipolar" materials. We show that the change in the crystal orientation has a strong impact on the morphological and optical properties of the nanostructures. The influence of growth conditions are also investigated by combining microscopy (SEM, TEM) and photoluminescence techniques. Finally, their potential as UV emitters will be discussed and the performances of GaN / (Al,Ga)N nanostructure-based LED demonstrators are presented.

Lamp1 Increases the Efficiency of Lassa Virus Infection by Promoting Fusion in Less Acidic Endosomal Compartments.

PubMed

Hulseberg, Christine E; Fénéant, Lucie; Szymańska, Katarzyna M; White, Judith M

2018-01-02

Lassa virus (LASV) is an arenavirus whose entry into host cells is mediated by a glycoprotein complex (GPC) comprised of a receptor binding subunit, GP1, a fusogenic transmembrane subunit, GP2, and a stable signal peptide. After receptor-mediated internalization, arenaviruses converge in the endocytic pathway, where they are thought to undergo low-pH-triggered, GPC-mediated fusion with a late endosome membrane. A unique feature of LASV entry is a pH-dependent switch from a primary cell surface receptor (α-dystroglycan) to an endosomal receptor, lysosomal-associated membrane protein (Lamp1). Despite evidence that the interaction between LASV GP1 and Lamp1 is critical, the function of Lamp1 in promoting LASV infection remains poorly characterized. Here we used wild-type (WT) and Lamp1 knockout (KO) cells to show that Lamp1 increases the efficiency of, but is not absolutely required for, LASV entry and infection. We then used cell-cell and pseudovirus-cell surface fusion assays to demonstrate that LASV GPC-mediated fusion occurs at a significantly higher pH when Lamp1 is present compared to when Lamp1 is missing. Correspondingly, we found that LASV entry occurs through less acidic endosomes in WT (Lamp1-positive) versus Lamp1 KO cells. We propose that, by elevating the pH threshold for fusion, Lamp1 allows LASV particles to exit the endocytic pathway before they encounter an increasingly acidic and harsh proteolytic environment, which could inactivate a significant percentage of incoming viruses. In this manner Lamp1 increases the overall efficiency of LASV entry and infection. IMPORTANCE Lassa virus is the most clinically important member of the Arenaviridae , a family that includes six additional biosafety level 4 (BSL4) hemorrhagic fever viruses. The lack of specific antiviral therapies for Lassa fever drives an urgent need to identify druggable targets, and interventions that block infection at the entry stage are particularly attractive. Lassa virus is only the second virus known to employ an intracellular receptor, the first being Ebola virus. Here we show that interaction with its intracellular receptor, Lamp1, enhances and upwardly shifts the pH dependence of fusion and consistently permits Lassa virus entry into cells through less acidic endosomes. We propose that in this manner, Lamp1 increases the overall efficiency of Lassa virus infection. Copyright © 2018 Hulseberg et al.

Glass-Based Transparent Conductive Electrode: Its Application to Visible-to-Ultraviolet Light-Emitting Diodes.

PubMed

Lee, Tae Ho; Kim, Kyeong Heon; Lee, Byeong Ryong; Park, Ju Hyun; Schubert, E Fred; Kim, Tae Geun

2016-12-28

Nitride-based ultraviolet light-emitting diodes (UV LEDs) are promising replacements for conventional UV lamps. However, the external quantum efficiency of UV LEDs is much lower than for visible LEDs due to light absorption in the p-GaN contact and electrode layers, along with p-AlGaN growth and doping issues. To minimize such absorption, we should obtain direct ohmic contact to p-AlGaN using UV-transparent ohmic electrodes and not use p-GaN as a contact layer. Here, we propose a glass-based transparent conductive electrode (TCE) produced using electrical breakdown (EBD) of an AlN thin film, and we apply the thin film to four (Al)GaN-based visible and UV LEDs with thin buffer layers for current spreading and damage protection. Compared to LEDs with optimal ITO contacts, our LEDs with AlN TCEs exhibit a lower forward voltage, higher light output power, and brighter light emission for all samples. The ohmic transport mechanism for current injection and spreading from the metal electrode to p-(Al)GaN layer via AlN TCE is also investigated by analyzing the p-(Al)GaN surface before and after EBD.

Maternal LAMP/p55gagHIV-1 DNA immunization induces in utero priming and a long-lasting immune response in vaccinated neonates.

PubMed

Rigato, Paula Ordonhez; Maciel, Milton; Goldoni, Adriana Letícia; Piubelli, Orlando Guerra; Orii, Noemia Mie; Marques, Ernesto Torres; August, Joseph Thomas; Duarte, Alberto José da Silva; Sato, Maria Notomi

2012-01-01

Infants born to HIV-infected mothers are at high risk of becoming infected during gestation or the breastfeeding period. A search is thus warranted for vaccine formulations that will prevent mother-to-child HIV transmission. The LAMP/gag DNA chimeric vaccine encodes the HIV-1 p55gag fused to the lysosome-associated membrane protein-1 (LAMP-1) and has been shown to enhance anti-Gag antibody (Ab) and cellular immune responses in adult and neonatal mice; such a vaccine represents a new concept in antigen presentation. In this study, we evaluated the effect of LAMP/gag DNA immunization on neonates either before conception or during pregnancy. LAMP/gag immunization of BALB/c mice before conception by the intradermal route led to the transfer of anti-Gag IgG1 Ab through the placenta and via breastfeeding. Furthermore, there were an increased percentage of CD4+CD25+Foxp3+T cells in the spleens of neonates. When offspring were immunized with LAMP/gag DNA, the anti-Gag Ab response and the Gag-specific IFN-γ-secreting cells were decreased. Inhibition of anti-Gag Ab production and cellular responses were not observed six months after immunization, indicating that maternal immunization did not interfere with the long-lasting memory response in offspring. Injection of purified IgG in conjunction with LAMP/gag DNA immunization decreased humoral and cytotoxic T-cell responses. LAMP/gag DNA immunization by intradermal injection prior to conception promoted the transfer of Ab, leading to a diminished response to Gag without interfering with the development of anti-Gag T- and B-cell memory. Finally, we assessed responses after one intravenous injection of LAMP/gag DNA during the last five days of pregnancy. The intravenous injection led to in utero immunization. In conclusion, DNA vaccine enconding LAMP-1 with Gag and other HIV-1 antigens should be considered in the development of a protective vaccine for the maternal/fetal and newborn periods.

Maternal LAMP/p55gagHIV-1 DNA Immunization Induces In Utero Priming and a Long-Lasting Immune Response in Vaccinated Neonates

PubMed Central

Rigato, Paula Ordonhez; Maciel, Milton; Goldoni, Adriana Letícia; Piubelli, Orlando Guerra; Orii, Noemia Mie; Marques, Ernesto Torres; August, Joseph Thomas; Duarte, Alberto José da Silva; Sato, Maria Notomi

2012-01-01

Infants born to HIV-infected mothers are at high risk of becoming infected during gestation or the breastfeeding period. A search is thus warranted for vaccine formulations that will prevent mother-to-child HIV transmission. The LAMP/gag DNA chimeric vaccine encodes the HIV-1 p55gag fused to the lysosome-associated membrane protein-1 (LAMP-1) and has been shown to enhance anti-Gag antibody (Ab) and cellular immune responses in adult and neonatal mice; such a vaccine represents a new concept in antigen presentation. In this study, we evaluated the effect of LAMP/gag DNA immunization on neonates either before conception or during pregnancy. LAMP/gag immunization of BALB/c mice before conception by the intradermal route led to the transfer of anti-Gag IgG1 Ab through the placenta and via breastfeeding. Furthermore, there were an increased percentage of CD4+CD25+Foxp3+T cells in the spleens of neonates. When offspring were immunized with LAMP/gag DNA, the anti-Gag Ab response and the Gag-specific IFN-γ-secreting cells were decreased. Inhibition of anti-Gag Ab production and cellular responses were not observed six months after immunization, indicating that maternal immunization did not interfere with the long-lasting memory response in offspring. Injection of purified IgG in conjunction with LAMP/gag DNA immunization decreased humoral and cytotoxic T-cell responses. LAMP/gag DNA immunization by intradermal injection prior to conception promoted the transfer of Ab, leading to a diminished response to Gag without interfering with the development of anti-Gag T- and B-cell memory. Finally, we assessed responses after one intravenous injection of LAMP/gag DNA during the last five days of pregnancy. The intravenous injection led to in utero immunization. In conclusion, DNA vaccine enconding LAMP-1 with Gag and other HIV-1 antigens should be considered in the development of a protective vaccine for the maternal/fetal and newborn periods. PMID:22355381

Advanced lighting guidelines: 1993. Final report

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

Eley, C.; Tolen, T.M.; Benya, J.R.

1993-12-31

The 1993 Advanced Lighting Guidelines document consists of twelve guidelines that provide an overview of specific lighting technologies and design application techniques utilizing energy-efficient lighting practice. Lighting Design Practice assesses energy-efficient lighting strategies, discusses lighting issues, and explains how to obtain quality lighting design and consulting services. Luminaires and Lighting Systems surveys luminaire equipment designed to take advantage of advanced technology lamp products and includes performance tables that allow for accurate estimation of luminaire light output and power input. The additional ten guidelines -- Computer-Aided Lighting Design, Energy-Efficient Fluorescent Ballasts, Full-Size Fluorescent Lamps, Compact Fluorescent Lamps, Tungsten-Halogen Lamps, Metal Halidemore » and HPS Lamps, Daylighting and Lumen Maintenance, Occupant Sensors, Time Scheduling Systems, and Retrofit Control Technologies -- each provide a product technology overview, discuss current products on the lighting equipment market, and provide application techniques. This document is intended for use by electric utility personnel involved in lighting programs, lighting designers, electrical engineers, architects, lighting manufacturers` representatives, and other lighting professionals.« less

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

Lall, Pradeep; Wei, Junchao; Sakalaukus, Peter

A new method has been developed for assessment of the onset of degradation in solid state luminaires to classify failure mechanisms by using metrics beyond lumen degradation that are currently used for identification of failure. Luminous Flux output, Correlated Color Temperature Data on Philips LED Lamps has been gathered under 85°C/85%RH till lamp failure. Failure modes of the test population of the lamps have been studied to understand the failure mechanisms in 85°C/85%RH accelerated test. Results indicate that the dominant failure mechanism is the discoloration of the LED encapsulant inside the lamps which is the likely cause for the luminousmore » flux degradation and the color shift. The acquired data has been used in conjunction with Bayesian Probabilistic Models to identify luminaires with onset of degradation much prior to failure through identification of decision boundaries between lamps with accrued damage and lamps beyond the failure threshold in the feature space. In addition luminaires with different failure modes have been classified separately from healthy pristine luminaires. The α-λ plots have been used to evaluate the robustness of the proposed methodology. Results show that the predicted degradation for the lamps tracks the true degradation observed during 85°C/85%RH during accelerated life test fairly closely within the ±20% confidence bounds. Correlation of model prediction with experimental results indicates that the presented methodology allows the early identification of the onset of failure much prior to development of complete failure distributions and can be used for assessing the damage state of SSLs in fairly large deployments. It is expected that, the new prediction technique will allow the development of failure distributions without testing till L70 life for the manifestation of failure.« less

LED downlights with non-circular spots

NASA Astrophysics Data System (ADS)

Parkyn, William A.; Pelka, David G.

2005-09-01

The ubiquitous downlight inhabits our ceilings by the millions. Hot, inefficient, and electrically wasteful, it is next in line for replacement by the latest high-brightness, high-efficacy white LEDs. The conventional downlight configuration of a large incandescent spotlight in a low-cost, ceiling-recessed metal can, represents the culmination of old technology, fated never to improve significantly. Incandescent downlights add greatly both to direct and indirect electrical consumption, with the lamps requiring relatively frequent replacement. The small size of LED emitters means small optical elements can produce much higher-quality beams than incandescent spotlight-lamps can produce. Herein we introduce compact high-luminosity LED downlights with lenses that deliver uniform illumination to delimited targets such as tables. One version utilizes circular lenses and micro-diffuser films to deliver square outputs. The other uses lenses cut to the target shape. In particular, one of these lenses is the first to offer a semicircular spot suitable for gambling tables.

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.

Characterising and testing deep UV LEDs for use in space applications

NASA Astrophysics Data System (ADS)

Hollington, D.; Baird, J. T.; Sumner, T. J.; Wass, P. J.

2015-12-01

Deep ultraviolet (DUV) light sources are used to neutralise isolated test masses in highly sensitive space-based gravitational experiments. An example is the LISA Pathfinder charge management system, which uses low-pressure mercury lamps. A future gravitational-wave observatory such as eLISA will use UV light-emitting diodes (UV LEDs), which offer numerous advantages over traditional discharge lamps. Such devices have limited space heritage but are now available from a number of commercial suppliers. Here we report on a test campaign that was carried out to quantify the general properties of three types of commercially available UV LEDs and demonstrate their suitability for use in space. Testing included general electrical and UV output power measurements, spectral stability, pulsed performance and temperature dependence, as well as thermal vacuum, radiation and vibration survivability.

An Analysis of Sources of Technological Change in Efficiency Improvement of Fluorescent Lamp Systems

NASA Astrophysics Data System (ADS)

Imanaka, Takeo

In Japan, energy efficient fluorescent lamp systems which use “rare-earth phosphors” and “electronic ballasts” have shown rapid diffusion since 1990s. This report investigated sources of technological change in the efficiency improvement of fluorescent lamp systems: (i) Fluorescent lamp and luminaires have been under steady technological development for getting more energy efficient lighting and the concepts to achieve high efficiency had been found in such activities; however, it took long time until they realized and become widely used; (ii) Electronic ballasts and rare-earth phosphors add fluorescent lamp systems not only energy efficiency but also various values such as compactness, lightweight, higher output, and better color rendering properties, which have also been expected and have induced research and development (R&D) (iii) Affordable electronic ballasts are realized by the new technology “power MOSFET” which is based on IC technologies and has been developed for large markets of information and communication technologies and mobile devices; and (iv) Rare-earth phosphors became available after rare-earth industries developed for the purpose of supplying rare-earth phosphors for color television. In terms of sources of technological change, (i) corresponds to “R&D” aiming at the particular purpose i.e. energy efficiency in this case, on the other hand, (ii), (iii), and (iv) correspond to “spillovers” from activities aiming at other purposes. This case exhibits an actual example in which “spillovers” were the critical sources of technological change in energy technology.

Biaxial Flexural Strength of High-Viscosity Glass-Ionomer Cements Heat-Cured with an LED Lamp during Setting

PubMed Central

Fabián Molina, Gustavo; Cabral, Ricardo Juan; Mazzola, Ignacio; Brain Lascano, Laura; Frencken, Jo E.

2013-01-01

Adding heat to glass ionomers during setting might improve mechanical properties. The aim was to compare the biaxial flexural strength (BFS) between and within four glass ionomers, by time of exposure to a high-intensity LED light-curing unit. Materials and methods. Samples of Fuji 9 Gold Label, Ketac Molar Easymix, ChemFil Rock, and the EQUIA system were divided into three treatment groups (n = 30): without heating (Group 1), heated with LED lamp of 1400 mW/cm2 for 30 s while setting (Group 2), and heated with LED lamp of 1400 mW/cm2 for 60 s while setting (Group 3). Samples were stored for 48 hours in distilled water at 37°C until tested. BFS was tested, using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed, using ANOVA test with the Bonferroni correction (α = 0.05). Heating the glass-ionomer cements with an LED curing light of 1400 mW/cm2 during setting for 30 s increased the BFS value of all GICs. No statistically significant difference in mean BFS scores was found between the EQUIA system and ChemFil Rock at 30 s and 60 s. The mean BFS value was statistically significantly higher for the EQUIA system and ChemFil Rock than for Fuji 9 Gold Label and Ketac Molar Easymix at all exposure times. PMID:23841095

Performance of light sources and radiation sensors under low gravity realized by parabolic airplane flights

NASA Astrophysics Data System (ADS)

Hirai, Hiroaki; Kitaya, Yoshiaki; Hirai, Takehiro

A fundamental study was conducted to establish an experimental system for space farming. Since to ensure optimal light for plant cultivation in space is of grave importance, this study examined the performance of light sources and radiation sensors under microgravity conditions created during the parabolic airplane flight. Three kinds of light sources, a halogen bulb, a fluorescent tube, and blue and red LEDs, and ten models of radiation sensors available in the market were used for the experiment. Surface temperature of the light sources, output signals from the radiation sensors, spectroscopic characteristics were measured at the gravity levels of 0.01, 1.0 and 1.8 G for 20 seconds each during parabolic airplane flights. As a result, the performance of the halogen lamp was affected the most by the gravity level among the three light sources. Under the microgravity conditions which do not raise heat convection, the temperature of the halogen lamp rose and the output of the radiation sensors increased. Spectral distributions of the halogen lamp indicated that peak wavelength appeared the highest at the level of 0.01G, which contributed to the increase in light intensity. In the case of red and blue LEDs, which are promising light sources in space farming, the temperature of both LED chips rose but irradiance from red LED increased and that from blue LED decreased under microgravity conditions due to the different thermal characteristics.

Biaxial flexural strength of high-viscosity glass-ionomer cements heat-cured with an LED lamp during setting.

PubMed

Fabián Molina, Gustavo; Cabral, Ricardo Juan; Mazzola, Ignacio; Brain Lascano, Laura; Frencken, Jo E

2013-01-01

Adding heat to glass ionomers during setting might improve mechanical properties. The aim was to compare the biaxial flexural strength (BFS) between and within four glass ionomers, by time of exposure to a high-intensity LED light-curing unit. Materials and methods. Samples of Fuji 9 Gold Label, Ketac Molar Easymix, ChemFil Rock, and the EQUIA system were divided into three treatment groups (n = 30): without heating (Group 1), heated with LED lamp of 1400 mW/cm(2) for 30 s while setting (Group 2), and heated with LED lamp of 1400 mW/cm(2) for 60 s while setting (Group 3). Samples were stored for 48 hours in distilled water at 37°C until tested. BFS was tested, using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed, using ANOVA test with the Bonferroni correction (α = 0.05). Heating the glass-ionomer cements with an LED curing light of 1400 mW/cm(2) during setting for 30 s increased the BFS value of all GICs. No statistically significant difference in mean BFS scores was found between the EQUIA system and ChemFil Rock at 30 s and 60 s. The mean BFS value was statistically significantly higher for the EQUIA system and ChemFil Rock than for Fuji 9 Gold Label and Ketac Molar Easymix at all exposure times.

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

Tuenge, Jason R.

The DOE Municipal Solid-State Street Lighting Consortium has evaluated four different LED replacements for existing ornamental post-top street lights in Sacramento, California. The project team was composed of the City and its consultant, PNNL (representing the Consortium), and the Sacramento Municipal Utility District. Product selection was finalized in March 2011, yielding one complete luminaire replacement and three lamp-ballast retrofit kits. Computer simulations, field measurements, and laboratory testing were performed to compare the performance and cost-effectiveness of the LED products relative to the existing luminaire with 100 W high-pressure sodium lamp. After it was confirmed the LED products were not equivalentmore » to HPS in terms of initial photopic illumination, the following parameters were scaled proportionally to enable equitable (albeit hypothetical) comparisons: light output, input wattage, and pricing. Four replacement scenarios were considered for each LED product, incorporating new IES guidance for mesopic multipliers and lumen maintenance extrapolation, but life cycle analysis indicated cost effectiveness was also unacceptable. Although LED efficacy and pricing continue to improve, this project serves as a timely and objective notice that LED technology may not be quite ready yet for such applications.« less

Powering a Home with Just 25 Watts of Solar PV. Super-Efficient Appliances Can Enable Expanded Off-Grid Energy Service Using Small Solar Power Systems

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

Phadke, Amol A.; Jacobson, Arne; Park, Won Young

Highly efficient direct current (DC) appliances have the potential to dramatically increase the affordability of off-grid solar power systems used for rural electrification in developing countries by reducing the size of the systems required. For example, the combined power requirement of a highly efficient color TV, four DC light emitting diode (LED) lamps, a mobile phone charger, and a radio is approximately 18 watts and can be supported by a small solar power system (at 27 watts peak, Wp). Price declines and efficiency advances in LED technology are already enabling rapidly increased use of small off-grid lighting systems in Africamore » and Asia. Similar progress is also possible for larger household-scale solar home systems that power appliances such as lights, TVs, fans, radios, and mobile phones. When super-efficient appliances are used, the total cost of solar home systems and their associated appliances can be reduced by as much as 50%. The results vary according to the appliances used with the system. These findings have critical relevance for efforts to provide modern energy services to the 1.2 billion people worldwide without access to the electrical grid and one billion more with unreliable access. However, policy and market support are needed to realize rapid adoption of super-efficient appliances.« less

Dental composite polymerization: a three different sources comparison

NASA Astrophysics Data System (ADS)

Sozzi, Michele; Fornaini, Carlo; Lagori, Giuseppe; Merigo, Elisabetta; Cucinotta, Annamaria; Vescovi, Paolo; Selleri, Stefano

2015-02-01

The introduction of photo-activators, with absorption spectra in the violet region, in composite resins raised interest in the use of 405 nm diode lasers for polymerization. The purpose of this research is the evaluation of the resins polymerization by means of violet diode laser compared to traditional lamps. Two different resins have been used for the experiments: Filtek Supreme XT flow (3M ESPE, USA) and Tetric Evo flow (Ivoclar, Vivadent). The photo-activator used is Camphoroquinone, alone, or in combination with Lucirin TPO. The resins have been cured with an halogen lamp (Heliolux DXL, Vivadent Ivoclar, Austria), a broadband LED curing light (Valo Ultradent, USA) and a 405 nm laser (Euphoton, Italy). The measure of cure depth, of the volumetric shrinkage, and the conversion degree (DC%) of the double bond during the curing process have been evaluated. A composite layer of 3 mm was cured in Filtek Supreme resin (Camphoroquinone activator), lower if compared to the use of the other two light sources. Tests on Tetric Evo (Camphoroquinone + Lucirin) didn't show any improvement of the use of laser compared to the halogen lamp and the broadband LED. By measuring the volumetric shrinkage the laser induced the lower change with both the composites. In terms of DC% the lower performance was obtained with the laser. Considering that the polymerization process strongly depends on the kind of composite used the effectiveness of 405 nm laser proved to be lower than halogen lamps and broadband LEDs.

Biomolecular and structural analyses of cauliflower-like DNAs by ultraviolet, circular dichroism, and fluorescence spectroscopies in comparison with natural DNA.

PubMed

Gill, Pooria; Ranjbar, Bijan; Saber, Reza; Khajeh, Khosro; Mohammadian, Mehdi

2011-07-01

Cauliflower-like DNAs are stem-loop DNAs that are fabricated periodically in inverted repetitions from deoxyribonucleic acid phosphates (dNTPs) by loop-mediated isothermal amplification (LAMP). Cauliflower-like DNAs have ladder-shape behaviors on gel electrophoresis, and increasing the time of LAMP leads to multiplying the repetitions, stem-loops, and electrophoretic bands. Cauliflower-like DNAs were fabricated via LAMP using two loop primers, two bumper primers, dNTPs, a λ-phage DNA template, and a Bst DNA polymerase in 75- and 90-min periods. These times led to manufacturing two types of cauliflower-like DNAs with different contents of inverted repetitions and stem-loops, which were clearly indicated by two comparable electrophoresis patterns in agarose gel. LAMP-fabricated DNAs and natural dsB-DNA (salmon genomic DNA) were dialyzed in Gomori phosphate buffer (10 mM, pH 7.4) to be isolated from salts, nucleotides, and primers. Dialyzed DNAs were studied using UV spectroscopy, circular dichroism spectropolarimetry, and fluorescence spectrophotometry. Structural analyses indicated reduction of the molecular ellipticity and extinction coefficients in comparison with B-DNA. Also, cauliflower-like DNAs demonstrated less intrinsic and more extrinsic fluorescence in comparison with natural DNA. The overwinding and lengthening of the cauliflower-like configurations of LAMP DNAs led to changes in physical parameters of this type of DNA in comparison with natural DNA. The results obtained introduced new biomolecular characteristics of DNA macromolecules fabricated within a LAMP process and show the effects of more inverted repeats and stem-loops, which are manufactured by lengthening the process.

Disparity between online and offline tests in accelerated aging tests of LED lamps under electric stress.

PubMed

Wang, Yao; Jing, Lei; Ke, Hong-Liang; Hao, Jian; Gao, Qun; Wang, Xiao-Xun; Sun, Qiang; Xu, Zhi-Jun

2016-09-20

The accelerated aging tests under electric stress for one type of LED lamp are conducted, and the differences between online and offline tests of the degradation of luminous flux are studied in this paper. The transformation of the two test modes is achieved with an adjustable AC voltage stabilized power source. Experimental results show that the exponential fitting of the luminous flux degradation in online tests possesses a higher fitting degree for most lamps, and the degradation rate of the luminous flux by online tests is always lower than that by offline tests. Bayes estimation and Weibull distribution are used to calculate the failure probabilities under the accelerated voltages, and then the reliability of the lamps under rated voltage of 220 V is estimated by use of the inverse power law model. Results show that the relative error of the lifetime estimation by offline tests increases as the failure probability decreases, and it cannot be neglected when the failure probability is less than 1%. The relative errors of lifetime estimation are 7.9%, 5.8%, 4.2%, and 3.5%, at the failure probabilities of 0.1%, 1%, 5%, and 10%, respectively.

Changing lamp type and position to improve lighting quality

NASA Astrophysics Data System (ADS)

Anizar; Syahputri, K.; Sari, RM; Rizkya, I.; Hardianti, DA

2018-03-01

This study investigates the lighting quality on the production floor in a cigarette paper industry by measuring illumination level and luminance. Cigarette paper inspection is performed manually by operators, and the criteria of defects are the cigarette paper has a hole, is rough and dirty. Operators complain that the room is pretty dark, which makes them unable to see clearly the cigarette paper defect. The government of Indonesia Health Ministerial Decree No 1405 The Year 2002 states that illumination level for continuous manual labor is 200 lux. Illumination level is measured for four days at 08.00, 10.00, 12.30, and 14.00 o’clock with 4 in 1 environmental meter. From the measurement result, it is found that using 7 LED lamps of 60 Watts can produce average illumination level of 70 lux. Low illuminance is caused by illumination level that does not meet the need 0f 569.759 lumen. Alternatives that can be used to increase lumen number are changing lamp type and position. One of the possibilities is using 24 LED of 138 Watts set 5.7 meters apart from one another can meet this demand. Another is using 5 LED of 150 Watts installed above the field of work.

Hyperspectral Image-Based Night-Time Vehicle Light Detection Using Spectral Normalization and Distance Mapper for Intelligent Headlight Control

PubMed Central

Kim, Heekang; Kwon, Soon; Kim, Sungho

2016-01-01

This paper proposes a vehicle light detection method using a hyperspectral camera instead of a Charge-Coupled Device (CCD) or Complementary metal-Oxide-Semiconductor (CMOS) camera for adaptive car headlamp control. To apply Intelligent Headlight Control (IHC), the vehicle headlights need to be detected. Headlights are comprised from a variety of lighting sources, such as Light Emitting Diodes (LEDs), High-intensity discharge (HID), and halogen lamps. In addition, rear lamps are made of LED and halogen lamp. This paper refers to the recent research in IHC. Some problems exist in the detection of headlights, such as erroneous detection of street lights or sign lights and the reflection plate of ego-car from CCD or CMOS images. To solve these problems, this study uses hyperspectral images because they have hundreds of bands and provide more information than a CCD or CMOS camera. Recent methods to detect headlights used the Spectral Angle Mapper (SAM), Spectral Correlation Mapper (SCM), and Euclidean Distance Mapper (EDM). The experimental results highlight the feasibility of the proposed method in three types of lights (LED, HID, and halogen). PMID:27399720

[Influence of cold spot temperature on 253.7 nm resonance spectra line of electrodeless discharge lamps].

PubMed

Dong, Jin-yang; Zhang, Gui-xin; Wang, Chang-quan

2012-01-01

As a kind of new electric light source, electrodeless discharge lamps are of long life, low mercury and non-stroboscopic light. The lighting effect of electrodeless discharge lamps depends on the radiation efficiency of 253.7 nm resonance spectra line to a large extent. The influence of cold temperature on 253.7 nm resonance spectra line has been studied experimentally by atomic emission spectral analysis. It was found that the radiation efficiency of 253.7 nm resonance spectra line is distributed in a nearly normal fashion with the variation of cold spot temperature, in other words, there is an optimum cold spot temperature for an electrodeless discharge lamp. At last, the results of experiments were analyzed through gas discharge theory, which offers guidance to the improvement of lighting effect for electrodeless discharge lamps.

Lighting Systems For High Speed Photography Applying Special Metal Halide Discharge Lamps

NASA Astrophysics Data System (ADS)

Gillum, Keith M.; Steuernagel, K. H.

1983-03-01

High speed photography requires, in addition to a good color quality of the light source, a very high level of illumination. Conventional lighting systems utilizing incandescent lamps or other metal halide lamp types has inherent problems of inefficient light output or poor color quality. Heat generated by incandescent lamps and the power these sources require drive up operating and installation costs. A most economical and practical solution was devised by using the metal halide discharge lamp developed by OSRAM, GmbH of Munich, West Germany. This lamp trade marked the HMITM Metallogen was primarily developed for the needs of the television and motion picture film industry. Due to their high efficiency and other consistent operating qualities these lamps also fulfill the needs of high speed photography, e.g. in crash test facilities, when special engineering activities are carried out. The OSRAM HMITM lamp is an AC discharge metal halide lamp with rare earth additives to increase both the efficiency and light output qualities. Since the lamp is an AC source, a special method had to be developed to overcome the strobing effect, which is normal for AC lamps given their modulated light output, when used with high speed cameras, (e.g. with >1000 fps). This method is based on an increased frequency for the lamp supply voltage coupled with a mix of the light output achieved using a multiphase mains power supply. First developed in 1977, this system using the OSRAM HMITM lamps was installed in a crash test facility of a major automotive manufacturer in West Germany. The design resulted in the best lighting and performance ever experienced. Since that time several other motor companies have made use of this breakthrough. Industrial and scientific users are now considering additional applications use of this advanced high speed lighting system.

Handheld lasers allow efficient detection of fluorescent marked organisms in the field.

PubMed

Rice, Kevin B; Fleischer, Shelby J; De Moraes, Consuelo M; Mescher, Mark C; Tooker, John F; Gish, Moshe

2015-01-01

Marking organisms with fluorescent dyes and powders is a common technique used in ecological field studies that monitor movement of organisms to examine life history traits, behaviors, and population dynamics. External fluorescent marking is relatively inexpensive and can be readily employed to quickly mark large numbers of individuals; however, the ability to detect marked organisms in the field at night has been hampered by the limited detection distances provided by portable fluorescent ultraviolet lamps. In recent years, significant advances in LED lamp and laser technology have led to development of powerful, low-cost ultraviolet light sources. In this study, we evaluate the potential of these new technologies to improve detection of fluorescent-marked organisms in the field and to create new possibilities for tracking marked organisms in visually challenging environments such as tree canopies and aquatic habitats. Using handheld lasers, we document a method that provides a fivefold increase in detection distance over previously available technologies. This method allows easy scouting of tree canopies (from the ground), as well as shallow aquatic systems. This novel detection method for fluorescent-marked organisms thus promises to significantly enhance the use of fluorescent marking as a non-destructive technique for tracking organisms in natural environments, facilitating field studies that aim to document otherwise inaccessible aspects of the movement, behavior, and population dynamics of study organisms, including species with significant economic impacts or relevance for ecology and human health.

Influence of interconnection on the long-term reliability of UV LED packages

NASA Astrophysics Data System (ADS)

Nieland, S.; Mitrenga, D.; Karolewski, D.; Brodersen, O.; Ortlepp, T.

2017-02-01

High power LEDs have conquered the mass market in recent years. Besides the main development focus to achieve higher productivity in the field of visible semiconductor LED processing, the wavelength range is further enhanced by active research and development in the direction of UVA / UVB / UVC. UVB and UVC LEDs are new and promising due to their numerous advantages. UV LEDs emit in a near range of one single emission peak with a width (FWHM) below 15 nm compared to conventional mercury discharge lamps and xenon sources, which show broad spectrums with many emission peaks over a wide range of wavelengths. Furthermore, the UV LED size is in the range of a few hundred microns and offers a high potential of significant system miniaturization. Of course, LED efficiency, lifetime and output power have to be increased [1]. Lifetime limiting issues of UVB/UVC-LED are the very high thermal stress in the chip resulting from the higher forward voltages (6-10 V @ 350 mA), the lower external quantum efficiency, below 10 % (most of the power disappears as heat), and the thermal resistance Rth of conventional LED packages being not able to dissipate these large amounts of heat for spreading. Beside the circuit boards and submounts which should have maximum thermal conductivity, the dimension of contacts as well as the interconnection of UV LED to the submount/package determinates the resolvable amount of heat [2]. In the paper different innovative interconnection techniques for UVC-LED systems will be discussed focused on the optimization of thermal conductivity in consideration of the assembly costs. Results on thermal simulation for the optimal contact dimensions and interconnections will be given. In addition, these theoretical results will be compared with results on electrical characterization as well as IR investigations on real UV LED packages in order to give recommendations for optimal UV LED assembly.

Expeditionary Lighting Systems for Military Shelters

DTIC Science & Technology

2009-11-04

Lumiled LED Housing Nonimaging Beamformer Heat Sink Connector Retractable Cable O Transportation Configuration Physical Optics Corporation (POC) LED...New Lighting Technologies: • Technology: Light Emitting Diode (LED) o Physical Optics Corp [SBIR] o Techshot [SBIR] [Congressional Effort o Jameson LED...rugged and durable—no lamp to damage or replace • Custom designed optical diffuser prevents glare and “eye spots” • Operates on universal voltage, 90

Long-term Stability of the Post-Flash LED Lamp

NASA Astrophysics Data System (ADS)

Martlin, Catherine; Baggett, Sylvia

2017-02-01

We report the results of a study of the long-term stability of the LED lamp used in post-flashing WFC3/UVIS images. We analyze 644 sub-array exposures taken over the course of just over 3 years and find no significant long-term trends in the LED lamp brightness. The average percentage change per year over all FLASH level and shutter combinations is found to be 0.15% per year with an uncertainty of ± 0.24% per year. The maximum measured percentage change per year was 0.39% for the highest FLASH level of 20 e- on shutter A which would indicate a change of less than 1 e-/pixel over the roughly 3 years since post-flashing began. There are, however, occasional short-term deviations in the LED output. The average minimum and maximum outliers over all FLASH level and shutter combination subsets are 4.1% below and 3.5% above, respectively, the mean of that subset. The maximum outlier over all the sets is 5.8% above the normalized mean value, for FLASH level 3/shutter A. The minimum outlier over all sets is also for FLASH level 3/shutter A and is 8.9% below the normalized mean value. Investigation of these outliers has revealed no systematic cause for the excursions and we recommend that users continue using the post-flash as they would have previously.

An aluminium nitride light-emitting diode with a wavelength of 210 nanometres.

PubMed

Taniyasu, Yoshitaka; Kasu, Makoto; Makimoto, Toshiki

2006-05-18

Compact high-efficiency ultraviolet solid-state light sources--such as light-emitting diodes (LEDs) and laser diodes--are of considerable technological interest as alternatives to large, toxic, low-efficiency gas lasers and mercury lamps. Microelectronic fabrication technologies and the environmental sciences both require light sources with shorter emission wavelengths: the former for improved resolution in photolithography and the latter for sensors that can detect minute hazardous particles. In addition, ultraviolet solid-state light sources are also attracting attention for potential applications in high-density optical data storage, biomedical research, water and air purification, and sterilization. Wide-bandgap materials, such as diamond and III-V nitride semiconductors (GaN, AlGaN and AlN; refs 3-10), are potential materials for ultraviolet LEDs and laser diodes, but suffer from difficulties in controlling electrical conduction. Here we report the successful control of both n-type and p-type doping in aluminium nitride (AlN), which has a very wide direct bandgap of 6 eV. This doping strategy allows us to develop an AlN PIN (p-type/intrinsic/n-type) homojunction LED with an emission wavelength of 210 nm, which is the shortest reported to date for any kind of LED. The emission is attributed to an exciton transition, and represents an important step towards achieving exciton-related light-emitting devices as well as replacing gas light sources with solid-state light sources.

Development of a new water sterilization device with a 365 nm UV-LED.

PubMed

Mori, Mirei; Hamamoto, Akiko; Takahashi, Akira; Nakano, Masayuki; Wakikawa, Noriko; Tachibana, Satoko; Ikehara, Toshitaka; Nakaya, Yutaka; Akutagawa, Masatake; Kinouchi, Yohsuke

2007-12-01

Ultraviolet (UV) irradiation is an effective disinfection method. In sterilization equipment, a low-pressure mercury lamp emitting an effective germicidal UVC (254 nm) is used as the light source. However, the lamp, which contains mercury, must be disposed of at the end of its lifetime or following damage due to physical shock or vibration. We investigated the suitability of an ultraviolet light-emitting diode at an output wavelength of 365 nm (UVA-LED) as a sterilization device, comparing with the other wavelength irradiation such as 254 nm (a low-pressure mercury lam) and 405 nm (LED). We used a commercially available UVA-LED that emitted light at the shortest wavelength and at the highest output energy. The new sterilization system using the UVA-LED was able to inactivate bacteria, such as Escherichia coli DH5 alpha, Enteropathogenic E. coli, Vibrio parahaemolyticus, Staphylococcus aureus, and Salmonella enterica serovar Enteritidis. The inactivations of the bacteria were dependent on the accumulation of UVA irradiation. Taking advantage of the safety and compact size of LED devices, we expect that the UVA-LED sterilization device can be developed as a new type of water sterilization device.

Liquid cooling applications on automotive exterior LED lighting

NASA Astrophysics Data System (ADS)

Aktaş, Mehmet; Şenyüz, Tunç; Şenyıldız, Teoman; Kılıç, Muhsin

2018-02-01

In this study cooling of a LED unit with heatsink and liquid cooling block which is used in automotive head lamp applications has been investigated numerically and experimentally. Junction temperature of a LED which is cooled with heatsink and liquid cooling block obtained in the experiment. 23°C is used both in the simulation and the experiment phase. Liquid cooling block material is choosed aluminium (Al) and polyamide. All tests and simulation are performed with three different flow rate. Temperature distribution of the designed product is investigated by doing the numerical simulations with a commercially software. In the simulations, fluid flow is assumed to be steady, incompressible and laminar and 3 dimensional (3D) Navier-Stokes equations are used. According to the calculations it is obtained that junction temperature is higher in the heatsink design compared to block cooled one. By changing the block material, it is desired to investigate the variation on the LED junction temperature. It is found that more efficient cooling can be obtained in block cooling by using less volume and weight. With block cooling lifetime of LED can be increased and flux loss can be decreased with the result of decreased junction temperature.

Efficient, full-spectrum, long-lived, non-toxic microwave lamp for plant growth

NASA Technical Reports Server (NTRS)

Maclennan, Donald A.; Turner, Brian P.; Dolan, James T.; Ury, Michael G.; Gustafson, Paul

1994-01-01

Fusion Systems Corporation has developed a mercury-free, low infrared, efficient microwave lamp using a benign sulfur based fill optimized for visible light. Our literature search and discussions with researchers directed us to enhance the bulbs red output. We have demonstrated a photosynthetic efficacy of over 2 micro-moles per microwave joule which corresponds to over 1.3 micro-moles per joule at the power main. Recent work has shown we can make additional increases in overall system efficiency. During the next two years, we expect to demonstrate a system capable of producing more than 1.5 micro-moles/joule measured at the power main with significantly less IR than alternative lamp systems. We determined optimal plant growth light requirements via a literature search and researcher input. We surveyed candidate lamp fill materials to be used in combination with sulfur and explored several methods of increasing photosynthetic efficacy.

Blackbody absorption efficiencies for six lamp pumped Nd laser materials

NASA Technical Reports Server (NTRS)

Cross, Patricia L.; Barnes, Norman P.; Skolaut, Milton W., Jr.; Storm, Mark E.

1990-01-01

Utilizing high resolution spectra, the absorption efficiencies for six Nd laser materials were calculated as functions of the effective blackbody temperature of the lamp and laser crystal size. The six materials were Nd:YAG, Nd:YLF, Nd:Q-98 Glass, Nd:YVO4, Nd:BEL, and Nd:Cr:GSGG. Under the guidelines of this study, Nd:Cr:GSGG's absorption efficiency is twice the absorption efficiency of any of the other laser materials.

CALiPER Report 20.3: Robustness of LED PAR38 Lamps

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

none,

2014-12-30

A small sample of each of the CALiPER Application Summary Report 20 PAR38 lamp types underwent stress testing that included substantial temperature and humidity changes, electrical variation, and vibration. The results do not directly address expected lifetime, but can be compared with one another, as well as with benchmark conventional products, to assess the relative robustness of the product designs.

Stability of Loop-Mediated Isothermal Amplification (LAMP) reagents and its amplification efficiency on crude trypanosome DNA templates.

PubMed

Thekisoe, Oriel M M; Bazie, Raoul S B; Coronel-Servian, Andrea M; Sugimoto, Chihiro; Kawazu, Shin-Ichiro; Inoue, Noboru

2009-04-01

This study evaluated the stability of LAMP reagents when stored at 25 degrees C and 37 degrees C, and also assessed its detection efficiency on different DNA template preparations. Accordingly, LAMP using reagents stored at 25 degrees C and 37 degrees C amplified DNA of in vitro cultured T. b. brucei (GUTat 3.1) from day 1 to day 15 of reagent storage. There were no significant differences (P>0.05) in detection sensitivity of LAMP among the reagents stored at 25 degrees C, 37 degrees C and -20 degrees C (recommended storage temperature). LAMP using the reagents stored at above-mentioned temperatures amplified serially diluted DNAs (genomic DNA extracted by phenol-chloroform method, FTA card and hemolysed blood) of T. b. gambiense (IL2343) with high sensitivity. Reactions were conducted on the reagents stored from 1 day to 30 days. LAMP detection sensitivity was poor when fresh blood as DNA template was added directly into reactive solution. Results of this study demonstrated that LAMP has the potential to be used in field conditions for diagnosis of trypanosome infections without being affected by ambient temperatures of tropical and sub-tropical countries where trypanosomosis is endemic.

Design of a cylindrical LED substrate without radiator

NASA Astrophysics Data System (ADS)

Tang, Fan; Guo, Zhenning

2017-12-01

To reduce the weight and production costs of light-emitting diode (LED) lamps, we applied the principle of the chimney effect to design a cylindrical LED substrate without a radiator. We built a 3D model by using Solidworks software and applied the flow simulation plug-in to conduct model simulation, thereby optimizing the heat source distribution and substrate thickness. The results indicate that the design achieved optimal cooling with a substrate with an upper extension length of 35 mm, a lower extension length of 8 mm, and a thickness of 1 mm. For a substrate of those dimensions, the highest LED chip temperature was 64.78 °C, the weight of the substrate was 35.09 g, and R jb = 7.00 K/W. If the substrate is powered at 8, 10, and 12 W, its temperature meets LED safety requirements. In physical tests, the highest temperature for a physical 8 W cylindrical LED substrate was 66 °C, which differed by only 1.22 °C from the simulation results, verifying the validity of the simulation. The designed cylindrical LED substrate can be used in high-power LED lamps that do not require radiators. This design is not only excellent for heat dissipation, but also for its low weight, low cost, and simplicity of manufacture.

Comparative Study of Light Sources for Household

NASA Astrophysics Data System (ADS)

Pawlak, Andrzej; Zalesińska, Małgorzata

2017-03-01

The article describes test results that provided the ground to define and evaluate basic photometric, colorimetric and electric parameters of selected, widely available light sources, which are equivalent to a traditional incandescent 60-Watt light bulb. Overall, one halogen light bulb, three compact fluorescent lamps and eleven LED light sources were tested. In general, it was concluded that in most cases (branded products, in particular) the measured and calculated parameters differ from the values declared by manufacturers only to a small degree. LED sources prove to be the most beneficial substitute for traditional light bulbs, considering both their operational parameters and their price, which is comparable with the price of compact fluorescent lamps or, in some instances, even lower.

[Energy saving and LED lamp lighting and human health].

PubMed

Deĭnego, V N; Kaptsov, V A

2013-01-01

The appearance of new sources of high-intensity with large proportion of blue light in the spectrum revealed new risks of their influence on the function of the eye and human health, especially for children and teenagers. There is an urgent need to reconsider the research methods of vision hygiene in conditions of energy-saving and LED bulbs lighting. On the basis of a systematic approach and knowledge of the newly discovered photosensitive receptors there was built hierarchical model of the interaction of "light environment - the eye - the system of formation of visual images - the hormonal system of the person - his psycho-physiological state." This approach allowed us to develop a range of risk for the negative impact of spectrum on the functions of the eye and human health, as well as to formulate the hygiene requirements for energy-efficient high-intensity light sources.

The Use of Light-Emitting Diodes (LEDs) as Green and Red/Far-Red Light Sources in Plant Physiology.

ERIC Educational Resources Information Center

Jackson, David L.; And Others

1985-01-01

The use of green, red, and far-red light-emitting diodes (LEDs) as light sources for plant physiological studies is outlined and evaluated. Indicates that LED lamps have the advantage over conventional light sources in that they are lightweight, low-cost, portable, easily constructed, and do not require color filters. (Author/DH)

Comparison of cap lamp and laser illumination for detecting visual escape cues in smoke

PubMed Central

Lutz, T.J.; Sammarco, J.J.; Srednicki, J.R.; Gallagher, S.

2015-01-01

The Illuminating Engineering Society of North America reports that an underground mine is the most difficult environment to illuminate (Rea, 2000). Researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) are conducting ongoing studies designed to explore different lighting technologies for improving mine safety. Underground miners use different visual cues to escape from a smoke-filled environment. Primary and secondary escapeways are marked with reflective ceiling tags of various colors. Miners also look for mine rail tracks. The main objective of this paper is to compare different lighting types and ceiling tag colors to differentiate what works best in a smoke-filled environment. Various cap lamps (LED and incandescent) and lasers (red, blue, green) were compared to see which options resulted in the longest detection distances for red, green and blue reflective markers and a section of mine rail track. All targets advanced toward the human subject inside of a smoke-filled room to simulate the subject walking in a mine environment. Detection distances were recorded and analyzed to find the best cap lamp, laser color and target color in a smoke environment. Results show that cap lamp, laser color and target color do make a difference in detection distances and are perceived differently based on subject age. Cap lamps were superior to lasers in all circumstances of ceiling tag detection, with the exception of the green laser. The incandescent cap lamp worked best in the simulated smoke compared to the LED cap lamps. The green laser was the best color for detecting the tags and track compared to the red and blue lasers. The green tags were the easiest color to detect on the ceiling. On average, the track was easier for the subjects to detect than the ceiling tags. PMID:26236146

Comparison of cap lamp and laser illumination for detecting visual escape cues in smoke.

PubMed

Lutz, T J; Sammarco, J J; Srednicki, J R; Gallagher, S

The Illuminating Engineering Society of North America reports that an underground mine is the most difficult environment to illuminate (Rea, 2000). Researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) are conducting ongoing studies designed to explore different lighting technologies for improving mine safety. Underground miners use different visual cues to escape from a smoke-filled environment. Primary and secondary escapeways are marked with reflective ceiling tags of various colors. Miners also look for mine rail tracks. The main objective of this paper is to compare different lighting types and ceiling tag colors to differentiate what works best in a smoke-filled environment. Various cap lamps (LED and incandescent) and lasers (red, blue, green) were compared to see which options resulted in the longest detection distances for red, green and blue reflective markers and a section of mine rail track. All targets advanced toward the human subject inside of a smoke-filled room to simulate the subject walking in a mine environment. Detection distances were recorded and analyzed to find the best cap lamp, laser color and target color in a smoke environment. Results show that cap lamp, laser color and target color do make a difference in detection distances and are perceived differently based on subject age. Cap lamps were superior to lasers in all circumstances of ceiling tag detection, with the exception of the green laser. The incandescent cap lamp worked best in the simulated smoke compared to the LED cap lamps. The green laser was the best color for detecting the tags and track compared to the red and blue lasers. The green tags were the easiest color to detect on the ceiling. On average, the track was easier for the subjects to detect than the ceiling tags.

10 CFR 431.325 - Units to be tested.

Code of Federal Regulations, 2011 CFR

2011-01-01

... EQUIPMENT Metal Halide Lamp Ballasts and Fixtures Test Procedures § 431.325 Units to be tested. For each basic model of metal halide lamp ballast selected for testing, a sample of sufficient size, no less than... energy efficiency calculated as the measured output power to the lamp divided by the measured input power...

Decontamination Efficiency of a DBD Lamp Containing an UV-C Emitting Phosphor.

PubMed

Caillier, Bruno; Caiut, José Maurício Almeida; Muja, Cristina; Demoucron, Julien; Mauricot, Robert; Dexpert-Ghys, Jeanette; Guillot, Philippe

2015-01-01

Among different physical and chemical agents, the UV radiation appears to be an important route for inactivation of resistant microorganisms. The present study introduces a new mercury-free Dielectric Barrier Discharge (DBD) flat lamp, where the biocide action comes from the UV emission produced by rare-earth phosphor obtained by spray pyrolysis, following plasma excitation. In this study, the emission intensity of the prototype lamp is tuned by controlling gas pressure and electrical power, 500 mbar and 15 W, corresponding to optimal conditions. In order to characterize the prototype lamp, the energetic output, temperature increase following lamp ignition and ozone production of the source were measured. The bactericidal experiments carried out showed excellent results for several gram-positive and gram-negative bacterial strains, thus demonstrating the high decontamination efficiency of the DBD flat lamp. Finally, the study of the external morphology of the microorganisms after the exposure to the UV emission suggested that other mechanisms than the bacterial DNA damage could be involved in the inactivation process. © 2015 The American Society of Photobiology.

Which lamp will be optimum to eye? Incandescent, fluorescent or LED etc

PubMed Central

Chen, Liang; Zhang, Xiao-Wei

2014-01-01

Low frequency flicker, high frequency flicker, strong light, strong blue light, infrared, ultraviolet, electromagnetic radiation, ripple flicker and dimming flicker produced by different lamps have negative impact on vision, eyes and health. Negative impact on eyes resulting in myopia or cataract etc: the solution is to remove all the negative factors by applying upright lighting technology and that is optimum to vision, eyes and health. PMID:24634884

Which lamp will be optimum to eye? Incandescent, fluorescent or LED etc.

PubMed

Chen, Liang; Zhang, Xiao-Wei

2014-01-01

Low frequency flicker, high frequency flicker, strong light, strong blue light, infrared, ultraviolet, electromagnetic radiation, ripple flicker and dimming flicker produced by different lamps have negative impact on vision, eyes and health. Negative impact on eyes resulting in myopia or cataract etc: the solution is to remove all the negative factors by applying upright lighting technology and that is optimum to vision, eyes and health.

Side- and end-illumination of polymer optical fibers in the UV region

NASA Astrophysics Data System (ADS)

Eckhardt, Hanns-S.; Jungling, B.; Klein, Karl-Friedrich; Poisel, Hans

2003-07-01

Since more than 2 decades, the polymer optical fiber (POF) based on PMMA is well known. A lot of applications were studied and initiated: in addition to data transmission, the automotive, lighting and sensor applications are of main interest. Due to the spectral attenuation and applications, light-sources like broadband metal-halide lamps and halogen lamps, or LEDs and laser-diodes are mainly used. Due to improvement in manufacturing of the standard step-index POF, the variations of the spectral attenuation in the blue region have been reduced. Therefore, the losses are acceptable for short-length applications in the UV-A region. Using different light-sources like high-power Xenon-lamp, deuterium-lamp or UV-LEDs, the UV-damage is an important factor. In addition to the basic attenuation, the UV-induced losses will be determined by experiment, in the interesting UV-A region. The higher flexibilty of the thick-core POF is superior in comparison to silica or glass fibers with the same outer diameter. Therefore, the bending losses in the UV-region are important, too. For special applications in the medical field, side-illuminating fibers are highly accepted. The axial and spectral dependence on the lateral radiation pattern will be described, using a very thick fiber.

Simple luminescence detectors using a light-emitting diode or a Xe lamp, optical fiber and charge-coupled device, or photomultiplier for determining proteins in capillary electrophoresis: a critical comparison.

PubMed

Casado-Terrones, Silvia; Fernández-Sánchez, Jorge F; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto

2007-06-01

The performance of two homemade fluorescence-induced capillary electrophoresis detectors, one based on light-emitting diode (LED) as the excitation source and a charge-coupled device (CCD) photodetector and the other based on a commercial luminescence spectrometer (Xe lamp) as the excitation source and a photomultiplier tube as a detector, were compared for the determination of fluorescent proteins R-phycoerythrin and B-phycoerythrin. Both devices use commercially available, reasonably priced optical components that can be used by nonexperts. After fine optimization of several optical and separation parameters in both devices, a zone capillary electrophoresis methodology was achieved with 50mM borate buffer (pH 8.4) and 10mM phytic acid for the determination of two phycobiliproteins. Detection limits of 0.50 and 0.64microg/ml for R-phycoerythrin and B-phycoerythrin, respectively, were achieved by using the LED-induced fluorescence capillary electrophoresis (LED-IF-CE) system, and corresponding detection limits of 2.73 and 2.16microg/ml were achieved by using the Xe lamp-IF-CE system. Analytical performance and other parameters, such as cost and potential to miniaturization, are compared for both devices.

Surface microhardness of a resin composite exposed to a "first-generation" LED curing lamp, in vitro.

PubMed

Keogh, Pauraic; Ray, Noel J; Lynch, Christopher D; Burke, Francis M; Hannigan, Ailish

2004-12-01

This investigation determined the minimum exposure times consistent with optimised surface microhardness parameters for a commercial resin composite cured using a "first-generation" light-emitting diode activation lamp. Disk specimens were exposed and surface microhardness numbers measured at the top and bottom surfaces for elapsed times of 1 hour and 24 hours. Bottom/top microhardness number ratios were also calculated. Most microhardness data increased significantly over the elapsed time interval but microhardness ratios (bottom/top) were dependent on exposure time only. A minimum exposure of 40 secs is appropriate to optimise microhardness parameters for the combination of resin composite and lamp investigated.

Long-term Stability of the WFC3 Post-Flash LED Lamp

NASA Astrophysics Data System (ADS)

Martlin, Catherine; Baggett, Sylvia M.

2017-06-01

We report the results of a study of the long-term stability of the LED lamp used in post-flashing WFC3/UVIS images (Martlin, C and Baggett, S., 2017). Having analyzed 644 sub-array exposures taken over the course of just over 3 years we find no significant long-term trends in the LED lamp brightness. The average percentage change per year over all FLASH level and shutter combinations is found to be 0.15% per year with an uncertainty of +/- 0.24% per year. The maximum measured percentage change per year was 0.39% for the highest FLASH level of 20 e- on shutter A which would indicate a change of less than 1 e-/pixel over the roughly 3 years since post-flashing began.There are, however, occasional short-term deviations in the LED output. The average minimum and maximum outliers over all FLASH level and shutter combination subsets are 4.1% below and 3.5% above, respectively, the mean of that subset. The maximum outlier over all the sets is 5.8% above the normalized mean value, for FLASH level 3/shutter A. The minimum outlier over all sets is also for FLASH level 3/shutter A and is 8.9% below the normalized mean value. Investigation of these outliers has revealed no systematic cause for the excursions and we recommend that users continue using the post-flash as they would have previously.

Evaluation of an LED Retrofit Project at Princeton University’s Carl Icahn Laboratory

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

Davis, Robert G.; Murphy, Arthur L.; Perrin, Tess E.

The LED lighting retrofit at the Carl Icahn Laboratory of the Lewis-Sigler Institute for Integrative Genomics was the first building-wide interior LED project at Princeton University, following the University’s experiences from several years of exterior and small-scale interior LED implementation projects. The project addressed three luminaire types – recessed 2x2 troffers, cove and other luminaires using linear T8 fluorescent lamps, and CFL downlights - which combined accounted for over 564,000 kWh of annual energy, over 90% of the lighting energy used in the facility. The Princeton Facilities Engineering staff used a thorough process of evaluating product alternatives before selecting anmore » acceptable LED retrofit solution for each luminaire type. Overall, 815 2x2 luminaires, 550 linear fluorescent luminaires, and 240 downlights were converted to LED as part of this project. Based solely on the reductions in wattage in converting from the incumbent fluorescent lamps to LED retrofit kits, the annual energy savings from the project was over 190,000 kWh, a savings of 37%. An additional 125,000 kWh of energy savings is expected from the implementation of occupancy and task-tuning control solutions, which will bring the total savings for the project to 62%.« less

Solid-state laser pumping with a planar compound parabolic concentrator.

PubMed

Panteli, D V; Pani, B M; Beli, L Z

1997-10-20

A novel solid-state laser-pumping scheme is proposed that combines a reflective lamp chamber and a compound parabolic concentrator (CPC) as a light guide. The CPC is made of a transparent material of high refractive index, and light is guided by the total internal reflection, with drastically reduced reflection losses. Material is chosen so that the absorption losses are minimized in the pumping wavelength range. The lamp chamber is designed with the principles of nonimaging optics, which ensures that the radiation is efficiently transferred from the lamp to the input aperture of the CPC. The pumping efficiency was first estimated theoretically, which gave us enough justification for the more accurate calculations with ray tracing. Single as well as multiple pumping cavities are discussed. New pumping geometry results in significantly increased pumping efficiency compared with conventional geometries. Also the lamp and the laser rod are separated, leading to reduced thermal load. We found that the proposed pumping method is also applicable to diode-pumped lasers.

Got Mercury?

NASA Technical Reports Server (NTRS)

Meyers, Valerie E.; McCoy, J. Torin; Garcia, Hector D.; James, John T.

2009-01-01

Many of the operational and payload lighting units used in various spacecraft contain elemental mercury. If these devices were damaged on-orbit, elemental mercury could be released into the cabin. Although there are plans to replace operational units with alternate light sources, such as LEDs, that do not contain mercury, mercury-containing lamps efficiently produce high quality illumination and may never be completely replaced on orbit. Therefore, exposure to elemental mercury during spaceflight will remain possible and represents a toxicological hazard. Elemental mercury is a liquid metal that vaporizes slowly at room temperature. However, it may be completely vaporized at the elevated operating temperatures of lamps. Although liquid mercury is not readily absorbed through the skin or digestive tract, mercury vapors are efficiently absorbed through the respiratory tract. Therefore, the amount of mercury in the vapor form must be estimated. For mercury releases from lamps that are not being operated, we utilized a study conducted by the New Jersey Department of Environmental Quality to calculate the amount of mercury vapor expected to form over a 2-week period. For longer missions and for mercury releases occurring when lamps are operating, we conservatively assumed complete volatilization of the available mercury. Because current spacecraft environmental control systems are unable to remove mercury vapors, both short-term and long-term exposures to mercury vapors are possible. Acute exposure to high concentrations of mercury vapors can cause irritation of the respiratory tract and behavioral symptoms, such as irritability and hyperactivity. Chronic exposure can result in damage to the nervous system (tremors, memory loss, insomnia, etc.) and kidneys (proteinurea). Therefore, the JSC Toxicology Group recommends that stringent safety controls and verifications (vibrational testing, etc.) be applied to any hardware that contains elemental mercury that could yield airborne mercury vapor concentrations greater than 0.1 mg/cu m in the total spacecraft atmosphere for exposures lasting 30 days or less or 0.01 mg/cu m mercury vapor for exposures lasting more than 30 days. We also encourage the use of alternative devices that do not contain mercury.

Direct-current converter for gas-discharge lamps

NASA Technical Reports Server (NTRS)

Lutus, P.

1980-01-01

Metal/halide and similar gas-discharge lamps are powered from low-voltage dc source using small efficient converter. Converter is useful whenever 60-cycle ac power is not available or where space and weight allocations are limited. Possible applications are offshore platforms, mobile homes, and emergency lighting. Design innovations give supply high reliability and efficiency up to 75 percent.

Efficient, full-spectrum, long-lived, non-toxic microwave lamp for plant growth

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

MacLennan, D.A.; Turner, B.P.; Dolan, J.T.

1994-12-31

Fusion Systems Corporation has developed a mercury-free, low infra-red, efficient microwave lamp using a benign sulfur based fill optimized for visible light. Our literature search and discussions with researchers directed us to enhance the bulbs red output. We have demonstrated a photosynthetic efficacy of over 2 micro-moles per microwave joule which corresponds to over 1.3 micro-moles per joule at the power main. Recent work has shown we can make additional increases in overall system efficiency. During the next two years, we expect to demonstrate a system capable of producing more than 1.5 micro-moles/joule measured at the power main with significantlymore » less IR than alternative lamp systems.« less

Low cost batch fabrication of microdevices using ultraviolet light-emitting diode photolithography technique

NASA Astrophysics Data System (ADS)

Lee, Neam Heng; Swamy, Varghese; Ramakrishnan, Narayanan

2016-01-01

Solid-state technology has enabled the use of light-emitting diodes (LEDs) in lithography systems due to their low cost, low power requirement, and higher efficiency relative to the traditional mercury lamp. Uniform irradiance distribution is essential for photolithography to ensure the critical dimension (CD) of the feature fabricated. However, light illuminated from arrays of LEDs can have nonuniform irradiance distribution, which can be a problem when using LED arrays as a source to batch-fabricate multiple devices on a large wafer piece. In this study, the irradiance distribution of an UV LED array was analyzed, and the separation distance between light source and mask optimized to obtain maximum irradiance uniformity without the use of a complex lens. Further, employing a diffuser glass enhanced the fabrication process and the CD loss was minimized to an average of 300 nm. To assess the performance of the proposed technology, batch fabrication of surface acoustic wave devices on lithium niobate substrate was carried out, and all the devices exhibited identical insertion loss of -18 dB at a resonance frequency of 39.33 MHz. The proposed low-cost UV lithography setup can be adapted in academic laboratories for research and teaching on microdevices.

Growth and development of Arabidopsis thaliana under single-wavelength red and blue laser light.

PubMed

Ooi, Amanda; Wong, Aloysius; Ng, Tien Khee; Marondedze, Claudius; Gehring, Christoph; Ooi, Boon S

2016-09-23

Indoor horticulture offers a sensible solution for sustainable food production and is becoming increasingly widespread. However, it incurs high energy and cost due to the use of artificial lighting such as high-pressure sodium lamps, fluorescent light or increasingly, the light-emitting diodes (LEDs). The energy efficiency and light quality of currently available horticultural lighting is suboptimal, and therefore less than ideal for sustainable and cost-effective large-scale plant production. Here, we demonstrate the use of high-powered single-wavelength lasers for indoor horticulture. They are highly energy-efficient and can be remotely guided to the site of plant growth, thus reducing on-site heat accumulation. Furthermore, laser beams can be tailored to match the absorption profiles of different plant species. We have developed a prototype laser growth chamber and demonstrate that plants grown under laser illumination can complete a full growth cycle from seed to seed with phenotypes resembling those of plants grown under LEDs reported previously. Importantly, the plants have lower expression of proteins diagnostic for light and radiation stress. The phenotypical, biochemical and proteome data show that the single-wavelength laser light is suitable for plant growth and therefore, potentially able to unlock the advantages of this next generation lighting technology for highly energy-efficient horticulture.

Growth and development of Arabidopsis thaliana under single-wavelength red and blue laser light

PubMed Central

Ooi, Amanda; Wong, Aloysius; Ng, Tien Khee; Marondedze, Claudius; Gehring, Christoph; Ooi, Boon S.

2016-01-01

Indoor horticulture offers a sensible solution for sustainable food production and is becoming increasingly widespread. However, it incurs high energy and cost due to the use of artificial lighting such as high-pressure sodium lamps, fluorescent light or increasingly, the light-emitting diodes (LEDs). The energy efficiency and light quality of currently available horticultural lighting is suboptimal, and therefore less than ideal for sustainable and cost-effective large-scale plant production. Here, we demonstrate the use of high-powered single-wavelength lasers for indoor horticulture. They are highly energy-efficient and can be remotely guided to the site of plant growth, thus reducing on-site heat accumulation. Furthermore, laser beams can be tailored to match the absorption profiles of different plant species. We have developed a prototype laser growth chamber and demonstrate that plants grown under laser illumination can complete a full growth cycle from seed to seed with phenotypes resembling those of plants grown under LEDs reported previously. Importantly, the plants have lower expression of proteins diagnostic for light and radiation stress. The phenotypical, biochemical and proteome data show that the single-wavelength laser light is suitable for plant growth and therefore, potentially able to unlock the advantages of this next generation lighting technology for highly energy-efficient horticulture. PMID:27659906

Handheld Lasers Allow Efficient Detection of Fluorescent Marked Organisms in the Field

PubMed Central

Fleischer, Shelby J.; De Moraes, Consuelo M.; Mescher, Mark C.; Tooker, John F.

2015-01-01

Marking organisms with fluorescent dyes and powders is a common technique used in ecological field studies that monitor movement of organisms to examine life history traits, behaviors, and population dynamics. External fluorescent marking is relatively inexpensive and can be readily employed to quickly mark large numbers of individuals; however, the ability to detect marked organisms in the field at night has been hampered by the limited detection distances provided by portable fluorescent ultraviolet lamps. In recent years, significant advances in LED lamp and laser technology have led to development of powerful, low-cost ultraviolet light sources. In this study, we evaluate the potential of these new technologies to improve detection of fluorescent-marked organisms in the field and to create new possibilities for tracking marked organisms in visually challenging environments such as tree canopies and aquatic habitats. Using handheld lasers, we document a method that provides a fivefold increase in detection distance over previously available technologies. This method allows easy scouting of tree canopies (from the ground), as well as shallow aquatic systems. This novel detection method for fluorescent-marked organisms thus promises to significantly enhance the use of fluorescent marking as a non-destructive technique for tracking organisms in natural environments, facilitating field studies that aim to document otherwise inaccessible aspects of the movement, behavior, and population dynamics of study organisms, including species with significant economic impacts or relevance for ecology and human health. PMID:26035303

Inactivation modeling of human enteric virus surrogates, MS2, Qβ, and ΦX174, in water using UVC-LEDs, a novel disinfecting system.

PubMed

Kim, Do-Kyun; Kim, Soo-Ji; Kang, Dong-Hyun

2017-01-01

In order to assure the microbial safety of drinking water, UVC-LED treatment has emerged as a possible technology to replace the use of conventional low pressure (LP) mercury vapor UV lamps. In this investigation, inactivation of Human Enteric Virus (HuEV) surrogates with UVC-LEDs was investigated in a water disinfection system, and kinetic model equations were applied to depict the surviving infectivities of the viruses. MS2, Qβ, and ΦX 174 bacteriophages were inoculated into sterile distilled water (DW) and irradiated with UVC-LED printed circuit boards (PCBs) (266nm and 279nm) or conventional LP lamps. Infectivities of bacteriophages were effectively reduced by up to 7-log after 9mJ/cm 2 treatment for MS2 and Qβ, and 1mJ/cm 2 for ΦX 174. UVC-LEDs showed a superior viral inactivation effect compared to conventional LP lamps at the same dose (1mJ/cm 2 ). Non-log linear plot patterns were observed, so that Weibull, Biphasic, Log linear-tail, and Weibull-tail model equations were used to fit the virus survival curves. For MS2 and Qβ, Weibull and Biphasic models fit well with R 2 values approximately equal to 0.97-0.99, and the Weibull-tail equation accurately described survival of ΦX 174. The level of UV-susceptibility among coliphages measured by the inactivation rate constant, k, was statistically different (ΦX 174 (ssDNA)>MS2, Qβ (ssRNA)), and indicated that sensitivity to UV was attributed to viral genetic material. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lighting innovations in concept cars

NASA Astrophysics Data System (ADS)

Berlitz, Stephan; Huhn, Wolfgang

2005-02-01

Concept cars have their own styling process. Because of the big media interest they give a big opportunity to bring newest technology with styling ideas to different fairgrounds. The LED technology in the concept cars Audi Pikes Peak, Nuvolari and Le Mans will be explained. Further outlook for the Audi LED strategy starting with LED Daytime Running Lamp will be given. The close work between styling and technical engineers results in those concept cars and further technical innovations based on LED technologies.

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

PubMed

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

2012-01-01

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

Portable lamp with dynamically controlled lighting distribution

DOEpatents

Siminovitch, Michael J.; Page, Erik R.

2001-01-01

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

Billion shot flashlamp for spaceborne lasers

NASA Technical Reports Server (NTRS)

Richter, Linda; Schuda, Felix; Degnan, John

1990-01-01

A billion-shot flashlamp developed under a NASA contract for spaceborne laser missions is presented. Lifetime-limiting mechanisms are identified and addressed. Two energy loadings of 15 and 44 Joules were selected for the initial accelerated life testing. A fluorescence-efficiency test station was used for measuring the useful-light output degradation of the lamps. The design characteristics meeting NASA specifications are outlined. Attention is focused on the physical properties of tungsten-matrix cathodes, the chemistry of dispenser cathodes, and anode degradation. It is reported that out of the total 83 lamps tested in the program, 4 lamps reached a billion shots and one lamp is beyond 1.7 billion shots, while at 44 Joules, 4 lamps went beyond 100 million shots and one lamp reached 500 million shots.

LAMP-2 deficiency leads to hippocampal dysfunction but normal clearance of neuronal substrates of chaperone-mediated autophagy in a mouse model for Danon disease.

PubMed

Rothaug, Michelle; Stroobants, Stijn; Schweizer, Michaela; Peters, Judith; Zunke, Friederike; Allerding, Mirka; D'Hooge, Rudi; Saftig, Paul; Blanz, Judith

2015-01-31

The Lysosomal Associated Membrane Protein type-2 (LAMP-2) is an abundant lysosomal membrane protein with an important role in immunity, macroautophagy (MA) and chaperone-mediated autophagy (CMA). Mutations within the Lamp2 gene cause Danon disease, an X-linked lysosomal storage disorder characterized by (cardio)myopathy and intellectual dysfunction. The pathological hallmark of this disease is an accumulation of glycogen and autophagic vacuoles in cardiac and skeletal muscle that, along with the myopathy, is also present in LAMP-2-deficient mice. Intellectual dysfunction observed in the human disease suggests a pivotal role of LAMP-2 within brain. LAMP-2A, one specific LAMP-2 isoform, was proposed to be important for the lysosomal degradation of selective proteins involved in neurodegenerative diseases such as Huntington's and Parkinson's disease. To elucidate the neuronal function of LAMP-2 we analyzed knockout mice for neuropathological changes, MA and steady-state levels of CMA substrates. The absence of LAMP-2 in murine brain led to inflammation and abnormal behavior, including motor deficits and impaired learning. The latter abnormality points to hippocampal dysfunction caused by altered lysosomal activity, distinct accumulation of p62-positive aggregates, autophagic vacuoles and lipid storage within hippocampal neurons and their presynaptic terminals. The absence of LAMP-2 did not apparently affect MA or steady-state levels of selected CMA substrates in brain or neuroblastoma cells under physiological and prolonged starvation conditions. Our data contribute to the understanding of intellectual dysfunction observed in Danon disease patients and highlight the role of LAMP-2 within the central nervous system, particularly the hippocampus.

Photomorphogenesis, photosynthesis, and seed yield of wheat plants grown under red light-emitting diodes (LEDs) with and without supplemental blue lighting

NASA Technical Reports Server (NTRS)

Goins, G. D.; Yorio, N. C.; Sanwo, M. M.; Brown, C. S.; Sager, J. C. (Principal Investigator)

1997-01-01

Red light-emitting diodes (LEDs) are a potential light source for growing plants in spaceflight systems because of their safety, small mass and volume, wavelength specificity, and longevity. Despite these attractive features, red LEDs must satisfy requirements for plant photosynthesis and photomorphogenesis for successful growth and seed yield. To determine the influence of gallium aluminium arsenide (GaAlAs) red LEDs on wheat photomorphogenesis, photosynthesis, and seed yield, wheat (Triticum aestivum L., cv. 'USU-Super Dwarf') plants were grown under red LEDs and compared to plants grown under daylight fluorescent (white) lamps and red LEDs supplemented with either 1% or 10% blue light from blue fluorescent (BF) lamps. Compared to white light-grown plants, wheat grown under red LEDs alone demonstrated less main culm development during vegetative growth through preanthesis, while showing a longer flag leaf at 40 DAP and greater main culm length at final harvest (70 DAP). As supplemental BF light was increased with red LEDs, shoot dry matter and net leaf photosynthesis rate increased. At final harvest, wheat grown under red LEDs alone displayed fewer subtillers and a lower seed yield compared to plants grown under white light. Wheat grown under red LEDs+10% BF light had comparable shoot dry matter accumulation and seed yield relative to wheat grown under white light. These results indicate that wheat can complete its life cycle under red LEDs alone, but larger plants and greater amounts of seed are produced in the presence of red LEDs supplemented with a quantity of blue light.

Engineering of a highly efficient Xe₂*-excilamp (xenon excimer lamp, λmax=172 nm, η=40%) and qualitative comparison to a low-pressure mercury lamp (LP-Hg, λ=185/254 nm) for water purification.

PubMed

Al-Gharabli, Samer; Engeßer, Patrick; Gera, Diana; Klein, Sandra; Oppenländer, Thomas

2016-02-01

Excilamps are mercury-free gas-discharge sources of non-coherent VUV or UV radiation with high radiant power and a long lifetime. The most efficient excilamp that is currently available on the market is a VUV xenon excilamp system (Xe2(*)-excimer lamp, λ(max) = 172 nm) with a stated radiant efficiency η of 40% at an electrical input power P(el) of 20 W, 50 W or 100 W. In this paper, the use of this highly efficient Xe2(*)-excilamp (P(el) = 20 W) for water treatment is demonstrated using a recirculating laboratory photoreactor system with negative radiation geometry. The efficiency in the 172 nm initiated bleaching of aqueous solutions of Rhodamine B is compared to that initiated by a common low-pressure mercury (LP-Hg) lamp (185 nm, TNN 15/32). The dependence of the pseudo zero order rate constant k´ of decolorization of RhB on the flow rate and on the initial concentration of RhB was investigated. Both lamps exhibited dependences of k´ on the initial concentration of RhB, which represents a typical saturation kinetical behavior. The saturation kinetics was very prominent in the case of the Xe2(*)-excilamp. Also, the Xe2(*)-excilamp treatment exhibited a significant influence on the flow rate of the RhB aqueous solution, which was not the case during the LP-Hg lamp initiated bleaching of RhB. The results of this paper demonstrate that Xe2(*)-excilamps can be used for VUV-initiated water purification. However, to reach the maximum efficacy of the Xe2(*)-excilamp for photo-initiated water purification further engineering optimization of the photoreactor concept is necessary. Copyright © 2015 Elsevier Ltd. All rights reserved.

Data rate enhancement of optical camera communications by compensating inter-frame gaps

NASA Astrophysics Data System (ADS)

Nguyen, Duy Thong; Park, Youngil

2017-07-01

Optical camera communications (OCC) is a convenient way of transmitting data between LED lamps and image sensors that are included in most smart devices. Although many schemes have been suggested to increase the data rate of the OCC system, it is still much lower than that of the photodiode-based LiFi system. One major reason of this low data rate is attributed to the inter-frame gap (IFG) of image sensor system, that is, the time gap between consecutive image frames. In this paper, we propose a way to compensate for this IFG efficiently by an interleaved Hamming coding scheme. The proposed scheme is implemented and the performance is measured.

An LED Solar Simulator for Student Labs

ERIC Educational Resources Information Center

González, Manuel I.

2017-01-01

Measuring voltage-current and voltage-power curves of a photovoltaic module is a nice experiment for high school and undergraduate students. In labs where real sunlight is not available this experiment requires a solar simulator. A prototype of a simulator using LED lamps has been manufactured and tested, and a comparison with classical halogen…

Development of the RGB LEDs color mixing mechanism for stability the color temperature at different projection distances.

PubMed

Hung, Chih-Ching

2015-01-01

In lighting application, the color mixing of the RGB LEDs can provide more color selection in correlated color temperature and color rendering. Therefore, the purpose of this study is to propose a RGB color mixing mechanism by applying the mechanism design. Three sets of lamp-type RGB LEDs are individually installed on three four-bar linkages. A crank is used to drive three groups of RGB LEDs lamp-type to project lights onto a single plane in order to mix the lights. And, simulations of the illuminance and associated color temperatures are conducted by changing the distance to the projection plane, under the assumption that the stability of the color temperature of the projected light does not change according to the projecting height. Thus, the effect of change in the color temperature on color determination by the humans' eyes was avoided. The success of the proposed method will allow medical personnel to choose suitable wavelengths and color temperatures according to the particular requirements of their medical-examination environments.

Stabilization of exosome-targeting peptides via engineered glycosylation.

PubMed

Hung, Michelle E; Leonard, Joshua N

2015-03-27

Exosomes are secreted extracellular vesicles that mediate intercellular transfer of cellular contents and are attractive vehicles for therapeutic delivery of bimolecular cargo such as nucleic acids, proteins, and even drugs. Efficient exosome-mediated delivery in vivo requires targeting vesicles for uptake by specific recipient cells. Although exosomes have been successfully targeted to several cellular receptors by displaying peptides on the surface of the exosomes, identifying effective exosome-targeting peptides for other receptors has proven challenging. Furthermore, the biophysical rules governing targeting peptide success remain poorly understood. To evaluate one factor potentially limiting exosome delivery, we investigated whether peptides displayed on the exosome surface are degraded during exosome biogenesis, for example by endosomal proteases. Indeed, peptides fused to the N terminus of exosome-associated transmembrane protein Lamp2b were cleaved in samples derived from both cells and exosomes. To suppress peptide loss, we engineered targeting peptide-Lamp2b fusion proteins to include a glycosylation motif at various positions. Introduction of this glycosylation motif both protected the peptide from degradation and led to an increase in overall Lamp2b fusion protein expression in both cells and exosomes. Moreover, glycosylation-stabilized peptides enhanced targeted delivery of exosomes to neuroblastoma cells, demonstrating that such glycosylation does not ablate peptide-target interactions. Thus, we have identified a strategy for achieving robust display of targeting peptides on the surface of exosomes, which should facilitate the evaluation and development of new exosome-based therapeutics. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Fundamental Characteristics of Deep-UV Light-Emitting Diodes and Their Application To Control Foodborne Pathogens

PubMed Central

Shin, Joo-Yeon; Kim, Soo-Ji; Kim, Do-Kyun

2015-01-01

Low-pressure mercury UV (LP-UV) lamps have long been used for bacterial inactivation, but due to certain disadvantages, such as the possibility of mercury leakage, deep-UV-C light-emitting diodes (DUV-LEDs) for disinfection have recently been of great interest as an alternative. Therefore, in this study, we examined the basic spectral properties of DUV-LEDs and the effects of UV-C irradiation for inactivating foodborne pathogens, including Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes, on solid media, as well as in water. As the temperature increased, DUV-LED light intensity decreased slightly, whereas LP-UV lamps showed increasing intensity until they reached a peak at around 30°C. As the irradiation dosage and temperature increased, E. coli O157:H7 and S. Typhimurium experienced 5- to 6-log-unit reductions. L. monocytogenes was reduced by over 5 log units at a dose of 1.67 mJ/cm2. At 90% relative humidity (RH), only E. coli O157:H7 experienced inactivation significantly greater than at 30 and 60% RH. In a water treatment study involving a continuous system, 6.38-, 5.81-, and 3.47-log-unit reductions were achieved in E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, at 0.5 liter per minute (LPM) and 200 mW output power. The results of this study suggest that the use of DUV-LEDs may compensate for the drawbacks of using LP-UV lamps to inactivate foodborne pathogens. PMID:26162872

A novel amblyopia treatment system based on LED light source

NASA Astrophysics Data System (ADS)

Zhang, Xiaoqing; Chen, Qingshan; Wang, Xiaoling

2011-05-01

A novel LED (light emitting diode) light source of five different colors (white, red, green, blue and yellow) is adopted instead of conventional incandescent lamps for an amblyopia treatment system and seven training methods for rectifying amblyopia are incorporated so as for achieving an integrated therapy. The LED light source is designed to provide uniform illumination, adjustable light intensity and alterable colors. Experimental tests indicate that the LED light source operates steadily and fulfills the technical demand of amblyopia treatment.

A novel amblyopia treatment system based on LED light source

NASA Astrophysics Data System (ADS)

Zhang, Xiaoqing; Chen, Qingshan; Wang, Xiaoling

2010-12-01

A novel LED (light emitting diode) light source of five different colors (white, red, green, blue and yellow) is adopted instead of conventional incandescent lamps for an amblyopia treatment system and seven training methods for rectifying amblyopia are incorporated so as for achieving an integrated therapy. The LED light source is designed to provide uniform illumination, adjustable light intensity and alterable colors. Experimental tests indicate that the LED light source operates steadily and fulfills the technical demand of amblyopia treatment.

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

Lall, Pradeep; Zhang, Hao; Davis, J Lynn

The energy efficiency of light-emitting diode (LED) technology compared to incandescent light bulbs has triggered an increased focus on solid state luminaries for a variety of lighting applications. Solid-state lighting (SSL) utilizes LEDs, for illumination through the process of electroluminescence instead of heating a wire filament as seen with traditional lighting. The fundamental differences in the construction of LED and the incandescent lamp results in different failure modes including lumen degradation, chromaticity shift and drift in the correlated color temperature. The use of LED-based products for safety-critical and harsh environment applications necessitates the characterization of the failure mechanisms and modes.more » In this paper, failure mechanisms and color stability has been studied for commercially available vertical structured thin film LED (VLED) under harsh environment conditions with and without the presence of contaminants. The VLED used for the study was mounted on a ceramic starboard in order to connect it to the current source. Contamination sources studied include operation in the vicinity of vulcanized rubber and adhesive epoxies in the presence of temperature and humidity. Performance of the VLEDs has been quantified using the measured luminous flux and color shift of the VLEDs subjected to both thermal and humidity stresses under a forward current bias of 350 mA. Results indicate that contamination can result in pre-mature luminous flux degradation and color shift in LEDs.« less

Demonstration Assessment of Light-Emitting Diode (LED) Roadway Lighting at the I-35W Bridge, Minneapolis, MN

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

Kinzey, Bruce R.; Myer, Michael

2009-08-31

This report describes the process and results of a demonstration of solid-state lighting (SSL) technology conducted in 2009 at the recently reconstructed I-35W bridge in Minneapolis, MN. The project was supported under the U.S. Department of Energy (DOE) Solid-State Lighting GATEWAY Technology Demonstration Program. Other participants in the demonstration project included the Minnesota Department of Transportation (Mn/DOT), Federal Highways Administration (FHWA), and BetaLED™ (a division of Ruud Lighting). Pacific Northwest National Laboratory (PNNL) conducted the measurements and analysis of the results. DOE has implemented a three-year evaluation of the LED luminaires in this installation in order to develop new longitudinalmore » field data on LED performance in a challenging, real-world environment. This document provides information through the initial phase of the I-35W bridge project, up to and including the opening of the bridge to the public and the initial feedback received on the LED lighting installation from bridge users. Initial findings of the evaluation are favorable, with minimum energy savings level of 13% for the LED installation relative to the simulated base case using 250W high-pressure sodium (HPS) fixtures. The LEDs had an average illuminance level of 0.91 foot candles compared to 1.29 fc for the HPS lamps. The LED luminaires cost $38,000 more than HPS lamps, yielding a lengthy payback period, however the bridge contractor had offered to include the LED luminaires as part of the construction package at no additional cost. One potentially significant benefit of the LEDs in this installation is avoiding rolling lane closures on the heavily-traveled interstate bridge for the purpose of relamping the HPS fixtures. Rolling lane closures involve multiple crew members and various maintenance and safety vehicles, diversion of traffic, as well as related administrative tasks (e.g., approvals, scheduling, etc.). Mn/DOT records show an average cost of relamping fixtures along interstate roadways of between $130-150 per pole. The previous bridge saw a lamp mortality rate of approximately 50% every two years, though the new bridge was designed to minimize many of the vibration issues. A voluntary Web-based feedback survey of nearly 500 self-described bridge users showed strong preference for the LED lighting - positive comments outnumbered negative ones by about five-to-one.« less

Investigations of HID Lamp Electrodes under HF Operation

NASA Astrophysics Data System (ADS)

Reinelt, Jens; Langenscheidt, Oliver; Westermeier, Michael; Mentel, Juergen; Awakowicz, Peter

2007-10-01

Low pressure lamps are operated many years at high frequencies to improve the efficiency of these lamps and drivers. For high pressure discharge lamps this operation mode has not been installed yet. Generally it can be assumed that there are changes in the electrode physics which may lead to an undesired lamp behavior if HID lamps are operated at a high frequency. To gain insights into these fundamental changes the so called Bochum Model Lamp is used. It is an easy system which allows a fundamental research on HID electrode behavior and the near electrode region without the occurrence of acoustic resonances. For the investigation phase resolved photography, pyrometry and spectrometry is used. The presented results describe changes in the electrode temperature and changes in the kind of arc attachment on the electrodes (diffuse and spot mode) depending on frequency. Also measurements of the Electrode-Sheath-Voltage (ESV), depending on frequency, are presented.

Optical radiation emissions from compact fluorescent lamps.

PubMed

Khazova, M; O'Hagan, J B

2008-01-01

There is a drive to energy efficiency to mitigate climate change. To meet this challenge, the UK Government has proposed phasing out incandescent lamps by the end of 2011 and replacing them with energy efficient fluorescent lighting, including compact fluorescent lamps (CFLs) with integrated ballasts. This paper presents a summary of an assessment conducted by the Health Protection Agency in March 2008 to evaluate the optical radiation emissions of CFLs currently available in the UK consumer market. The study concluded that the UV emissions from a significant percentage of the tested CFLs with single envelopes may result in foreseeable overexposure of the skin when these lamps are used in desk or task lighting applications. The optical output of all tested CFLs, in addition to high-frequency modulation, had a 100-Hz envelope with modulation in excess of 15%. This degree of modulation may be linked to a number of adverse effects.

Enhanced photobactericidal activity of ZnO nanorods modified by meso-tetrakis(4-sulfonatophenyl)porphyrin under visible LED lamp irradiation.

PubMed

Rahimi, Rahmatollah; Shokraiyan, Javad; Rabbani, Mahboubeh; Fayyaz, Fatemeh

2015-01-01

In this study, zinc oxide (ZnO) nanorods have been synthesized using a simple template-free precipitation technique and deposited on glass substrate. The meso-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) has been synthesized and then immobilized on the surface of ZnO nanorods to prepare an organic/inorganic composite. The samples were characterized by various techniques such as X-ray diffraction, diffuse reflectance spectra, Fourier transform-infrared spectroscopy and scanning electron microscopy. In addition, the photobactericidal activity of TPPS/ZnO composite, TPPS and ZnO nanorods was tested against the pathogenic bacterium of Escherichia coli under visible LED lamp irradiation. The results indicate that the photobactericidal activity of TPPS-loaded ZnO nanorods was better than TPPS or ZnO nanorods, separately.

Industrial application of the decomposition of CO2 . NOx by large flow atmospheric microwave plasma LAMP employed in motorcar

NASA Astrophysics Data System (ADS)

Pandey, Anil; Niwa, Syunta; Morii, Yoshinari; Ikezawa, Shunjiro

2012-10-01

In order to decompose CO2 . NOx [1], we have developed the large flow atmospheric microwave plasma; LAMP [2]. It is very important to apply it for industrial innovation, so we have studied to apply the LAMP into motorcar. The characteristics of the developed LAMP are that the price is cheap and the decomposition efficiencies of CO2 . NOx are high. The mechanism was shown as the vertical configuration between the exhaust gas pipe and the waveguide was suitable [2]. The system was set up in the car body with a battery and an inverter. The battery is common between the engine and the inverter. In the application of motorcar, the flow is large, so the LAMP which has the merits of large flow, high efficient decomposition, and cheap apparatus will be superior.[4pt] [1] H. Barankova, L. Bardos, ISSP 2011, Kyoto.[0pt] [2] S. Ikezawa, S. Parajulee, S. Sharma, A. Pandey, ISSP 2011, Kyoto (2011) pp. 28-31; S. Ikezawa, S. Niwa, Y. Morii, JJAP meeting 2012, March 16, Waseda U. (2012).

Investigation of interface property in Al/SiO2/ n-SiC structure with thin gate oxide by illumination

NASA Astrophysics Data System (ADS)

Chang, P. K.; Hwu, J. G.

2017-04-01

The reverse tunneling current of Al/SiO2/ n-SiC structure employing thin gate oxide is introduced to examine the interface property by illumination. The gate current at negative bias decreases under blue LED illumination, yet increases under UV lamp illumination. Light-induced electrons captured by interface states may be emitted after the light sources are off, leading to the recovery of gate currents. Based on transient characteristics of gate current, the extracted trap level is close to the light energy for blue LED, indicating that electron capture induced by lighting may result in the reduction of gate current. Furthermore, bidirectional C- V measurements exhibit a positive voltage shift caused by electron trapping under blue LED illumination, while a negative voltage shift is observed under UV lamp illumination. Distinct trapping and detrapping behaviors can be observed from variations in I- V and C- V curves utilizing different light sources for 4H-SiC MOS capacitors with thin insulators.

A broadband LED source in visible to short-wave-infrared wavelengths for spectral tumor diagnostics

NASA Astrophysics Data System (ADS)

Hayashi, Daiyu; van Dongen, Anne Marie; Boerekamp, Jack; Spoor, Sandra; Lucassen, Gerald; Schleipen, Jean

2017-06-01

Various tumor types exhibit the spectral fingerprints in the absorption and reflection spectra in visible and especially in near- to short-wave-infrared wavelength ranges. For the purpose of spectral tumor diagnostics by means of diffuse reflectance spectroscopy, we developed a broadband light emitting diode (LED) source consisting of a blue LED for optical excitation, Lu3Al5O12:Ce3+,Cr3+ luminescent garnet for visible to near infrared emissions, and Bismuth doped GeO2 luminescent glass for near-infrared to short-wave infrared emissions. It emits broad-band light emissions continuously in 470-1600 nm with a spectral gap at 900-1000 nm. In comparison to the currently available broadband light sources like halogen lamps, high-pressure discharge lamps and super continuum lasers, the light sources of this paper has significant advantages for spectral tissue diagnostics in high-spectral stability, improved light coupling to optical fibers, potential in low light source cost and enabling battery-drive.

Agile Robust Autonomy: Inspired by Connecting Natural Flight and Biological Sensors

DTIC Science & Technology

2017-03-01

stabilization in insects while tethered. The stimulating is a rotating horizon line produced by UV and green LEDs (Figure 2). DISTRIBUTION A 12...recordings from the eyes. In the damselflies, we recorded from the compound eyes. The stimulation is a xenon light lamp producing light from the UV to near...addition to a green LED . One green light LED recording was taken after each spectral measurement. ............... 29 24. KHILS Projector Spectral

Trace Contaminant Control: An In-Depth Study of a Silica-Titania Composite for Photocatalytic Remediation of Closed-Environment Habitat Air

NASA Technical Reports Server (NTRS)

Coutts, Janelle L.

2013-01-01

This collection of studies focuses on a PCO system for the oxidation of a model compound, ethanol, using an adsorption-enhanced silica-TiO2 composite (STC) as the photocatalyst; studies are aimed at addressing the optimization of various parameters including light source, humidity, temperature, and possible poisoning events for use as part of a system for gaseous trace-contaminant control system in closed-environment habitats. The first goal focused on distinguishing the effect of photon flux (i.e., photons per unit time reaching a surface) from that of photon energy (i.e., wavelength) of a photon source on the PCO of ethanol. Experiments were conducted in a bench-scale annular reactor packed with STC pellets and irradiated with either a UV-A fluorescent black light blue lamp O max=365 nm) at its maximum light intensity or a UV-C germicidal lamp O. max=254 nm) at three levels of light intensity. The STC-catalyzed oxidation of ethanol was found to follow zero-order kinetics with respect to CO2 production, regardless of the photon source. Increased photon flux led to increased EtOH removal, mineralization, and oxidation rate accompanied by lower intermediate concentration in the effluent. The oxidation rate was higher in the reactor irradiated by UV-C than by UV-A (38.4 vs. 31.9 nM s-1 ) at the same photon flux, with similar trends for mineralization (53.9 vs. 43.4%) and reaction quantum efficiency (i.e., photonic efficiency, 63.3 vs. 50.1 nmol C02 mol photons-1 ). UV-C irradiation also led to decreased intermediate concentration in the effluent compared to UV -A irradiation. These results demonstrated that STC-catalyzed oxidation is enhanced by both increased photon flux and photon energy. The effect of temperature and relative humidity on the STC-catalyzed degradation of ethanol was also determined using the UV-A light source at its maximum intensity.

Impact of watering with UV-LED-treated wastewater on microbial and physico-chemical parameters of soil.

PubMed

Chevremont, A-C; Boudenne, J-L; Coulomb, B; Farnet, A-M

2013-04-15

Advanced oxidation processes based on UV radiations have been shown to be a promising wastewater disinfection technology. The UV-LED system involves innovative materials and could be an advantageous alternative to mercury-vapor lamps. The use of the UV-LED system results in good water quality meeting the legislative requirements relating to wastewater reuse for irrigation. The aim of this study was to investigate the impact of watering with UV-LED treated wastewaters (UV-LED WW) on soil parameters. Solid-state ¹³C NMR shows that watering with UV-LED WW do not change the chemical composition of soil organic matter compared to soil watered with potable water. Regarding microbiological parameters, laccase, cellulase, protease and urease activities increase in soils watered with UV-LED WW which means that organic matter brought by the effluent is actively degraded by soil microorganisms. The functional diversity of soil microorganisms is not affected by watering with UV-LED WW when it is altered by 4 and 8 months of watering with wastewater (WW). After 12 months, functional diversity is similar regardless of the water used for watering. The persistence of faecal indicator bacteria (coliform and enterococci) was also determined and watering with UV-LED WW does not increase their number nor their diversity unlike soils irrigated with activated sludge wastewater. The study of watering-soil microcosms with UV-LED WW indicates that this system seems to be a promising alternative to the UV-lamp-treated wastewaters. Copyright © 2013 Elsevier Ltd. All rights reserved.

Multiple intensity distributions from a single optical element

NASA Astrophysics Data System (ADS)

Berens, Michael; Bruneton, Adrien; Bäuerle, Axel; Traub, Martin; Wester, Rolf; Stollenwerk, Jochen; Loosen, Peter

2013-09-01

We report on an extension of the previously published two-step freeform optics tailoring algorithm using a Monge-Kantorovich mass transportation framework. The algorithm's ability to design multiple freeform surfaces allows for the inclusion of multiple distinct light paths and hence the implementation of multiple lighting functions in a single optical element. We demonstrate the procedure in the context of automotive lighting, in which a fog lamp and a daytime running lamp are integrated in a single optical element illuminated by two distinct groups of LEDs.

Kinetic study of acetaminophen degradation by visible light photocatalysis.

PubMed

Gotostos, Mary Jane N; Su, Chia-Chi; De Luna, Mark Daniel G; Lu, Ming-Chun

2014-01-01

In this work, a novel photocatalyst K3[Fe(CN)6]/TiO2 synthesized via a simple sol-gel method was utilized to degrade acetaminophen (ACT) under visible light with the use of blue and green LED lights. Parameters (medium pH, initial concentration of reactant, catalyst concentration, temperature, and number of blue LED lights) affecting photocatalytic degradation of ACT were also investigated. The experimental result showed that compared to commercially available Degussa P-25 (DP-25) photocatalyst, K3[Fe(CN)6]/TiO2 gave higher degradation efficiency and rate constant (kapp) of ACT. The degradation efficiency or kapp decreased with increasing initial ACT concentration and temperature, but increased with increased number of blue LED lamps. Additionally, kapp increased as initial pH was increased from 5.6 to 6.9, but decreased at a high alkaline condition (pH 8.3). Furthermore, the degradation efficiency and kapp of ACT increased as K3[Fe(CN)6]/TiO2 loading was increased to 1 g L(-1) but decreased and eventually leveled off at photocatalyst loading above this value. Photocatalytic degradation of ACT in K3[Fe(CN)6]/TiO2 catalyst system follows a pseudo-first-order kinetics. The Langmuir-Hinshelwood equation was also satisfactorily used to model the degradation of ACT in K3[Fe(CN)6]/TiO2 catalyst system indicated by a satisfactory linear correlation between 1/kapp and Co, with kini = 6.54 × 10(-4) mM/min and KACT = 17.27 mM(-1).

Photolysis of low concentration H2S under UV/VUV irradiation emitted from microwave discharge electrodeless lamps.

PubMed

Xia, Lan-Yan; Gu, Ding-Hong; Tan, Jing; Dong, Wen-Bo; Hou, Hui-Qi

2008-04-01

The photolysis of simulating low concentration of hydrogen sulfide malodorous gas was studied under UV irradiation emitted by self-made microwave discharge electrodeless lamps (i.e. microwave UV electrodeless mercury lamp (185/253.7 nm) and iodine lamp (178.3/180.1/183/184.4/187.6/206.2 nm)). Experiments results showed that the removal efficiency (eta H2S) of hydrogen sulfide was decreased with increasing initial H2S concentration and increased slightly with gas residence time; H2S removal efficiency was decreased dramatically with enlarged pipe diameter. Under the experimental conditions with pipe diameter of 36 mm, gas flow rate of 0.42 standard l s(-1), eta H2S was 52% with initial H2S concentration of 19.5 mg m(-3) by microwave mercury lamp, the absolute removal amount (ARA) was 4.30 microg s(-1), and energy yield (EY) was 77.3 mg kW h(-1); eta H2S was 56% with initial H2S concentration of 18.9 mg m(-3) by microwave iodine lamp, the ARA was 4.48 microg s(-1), and the EY was 80.5mg kW h(-1). The main photolysis product was confirmed to be SO4(2-) with IC.

An LED Approach for Measuring the Photocatalytic Breakdown of Crystal Violet Dye

NASA Technical Reports Server (NTRS)

Ryan, Robert E.; Underwood, Lauren W.; ONeal, Duane; Pagnutti, Mary; Davis, Bruce A.

2009-01-01

A simple technique to assess the reactivity of photocatalytic coatings sprayed onto transmissive glass surfaces was developed. This new method uses ultraviolet (UV) gallium nitride (GaN) light-emitting diodes (LEDs) to drive a photocatalytic reaction (the photocatalytic breakdown of a UV-resistant dye applied to a surface coated with the semiconductor titanium dioxide); and then a combination of a stabilized white light LED and a spectrometer to track the dye degradation as a function of time. Simple, standardized evaluation techniques that assess photocatalytic materials over a variety of environmental conditions, including illumination level, are not generally available and are greatly needed prior to in situ application of photocatalytic technologies. To date, much research pertaining to this aspect of photocatalysis has been limited and has focused primarily on laboratory experiments using mercury lamps. Mercury lamp illumination levels are difficult to control over large ranges and are temporally modulated by line power, limiting their use in helping to understand and predict how photocatalytic materials will behave in natural environmental settings and conditions. The methodology described here, using steady-state LEDs and time series spectroradiometric techniques, is a novel approach to explore the effect of UV light on the photocatalytic degradation of a UV resistant dye (crystal violet). GaN UV LED arrays, centered around 365 nm with an adjustable DC power supply, are used to create a small, spatially uniform light field where the steady state light level can be varied over three to four orders of magnitude. For this study, a set of glass microscope slides was custom coated with a thinly sprayed layer of photocatalytic titanium dioxide. Crystal violet was then applied to these titanium-dioxide coated slides and to uncoated control slides. The slides were then illuminated at various light levels from the dye side of the slide by the UV LED array. To monitor dye degradation on the slides over time, a temperature-stabilized white light LED was used to illuminate the opposite side of the slides. As the dye degraded, the amount of light from the white light LED transmitted through the slide was monitored with a spectrometer and subsequently analyzed to determine and compare the rate of dye degradation for photocatalytically coated versus uncoated slide surfaces. The long-term stability of the spectrometer/white light LED combination, which required only a single reference spectra to be taken for a time series sequence of several hours, enabled accurate measurements of transmitted light over time. Time series transmission curves were generated and results demonstrated that over time the transmission increased much more rapidly on the coated slides than on the control slides. This experimental configuration and methodology for photocatalytic activity measurement minimizes many external variable effects and allows low light level studies to be performed. This study also compares the advantages of this novel LED light source design to traditional mercury lamp systems and non-LED lamp approaches that have conventionally been used. The methodology and experimental design research summarized in this abstract is partly funded by the Department of Homeland Security, Science and Technology Directorate, and by the NASA Stennis Space Center Innovative Partnerships Program.

Performance of a nonlaser light source for photodynamic therapy

NASA Astrophysics Data System (ADS)

Whitehurst, Colin; Byrne, Karen T.; Morton, Colin; Moore, James V.

1995-03-01

Advances in short arc technology and optical filter coatings led to the design and construction of a table-top light source in 1989; the first viable and cost-effective alternative to a laser. The device can deliver over 3 W within a 30 nm band centered at any wavelength from 200 nm to 1200 nm at fluence rates of over 1 W cm-2. Its relative biological effectiveness (RBE) in vitro has been proven alongside an argon pumped dye laser and a copper vapor pumped dye laser. These in vitro tests showed an efficiency of hematoporphyrin derivative (HPD) induced cellular photoinactivation close to that of the argon/dye laser (RBE 100%), with a mean RBE for the lamp of 87 +/- 3% (p < 0.05). The lamp proved to be superior to that of the copper/dye laser system with an RBE of up to 150% at fluence rates above 50 mWcm-2. In vivo tests show that the extent and depth of tumor necrosis are comparable to that of an argon/dye laser. An in situ bioassay using tumor regrowth delay is currently underway. Early clinical trials show clearance of Bowen's disease and actinic keratosis using the same light fluences as costly PDT lasers.

Enhancing lutein productivity of an indigenous microalga Scenedesmus obliquus FSP-3 using light-related strategies.

PubMed

Ho, Shih-Hsin; Chan, Ming-Chang; Liu, Chen-Chun; Chen, Chun-Yen; Lee, Wen-Lung; Lee, Duu-Jong; Chang, Jo-Shu

2014-01-01

Lutein, one of the main photosynthetic pigments, is a promising natural product with both nutritional and pharmaceutical applications. In this study, light-related strategies were applied to enhance the cell growth and lutein production of a lutein-rich microalga Scenedesmus obliquus FSP-3. The results demonstrate that using white LED resulted in better lutein production efficiency when compared to the other three monochromatic LEDs (red, blue, and green). The lutein productivity of S. obliquus FSP-3 was further improved by adjusting the type of light source and light intensity. The optimal lutein productivity of 4.08 mg/L/d was obtained when using a TL5 fluorescent lamp at a light intensity of 300 μmol/m(2)/s, and this performance is better than that reported in most related studies. Moreover, the time-course profile of lutein accumulation in the microalga shows that the maximal lutein content and productivity were obtained at the onset of nitrogen depletion. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mobilizing slit lamp to the field: A new affordable solution

PubMed Central

Farooqui, Javed Hussain; Jorgenson, Richard; Gomaa, Ahmed

2015-01-01

We are describing a simple and affordable design to pack and carry the slit lamp to the field. Orbis staff working on the Flying Eye Hospital (FEH) developed this design to facilitate mobilization of the slit lamp to the field during various FEH programs. The solution involves using a big toolbox, a central plywood apparatus, and foam. These supplies were cut to measure and used to support the slit lamp after being fitted snuggly in the box. This design allows easy and safe mobilization of the slit lamp to remote places. It was developed with the efficient use of space in mind and it can be easily reproduced in developing countries using same or similar supplies. Mobilizing slit lamp will be of great help for staff and institutes doing regular outreach clinical work. PMID:26669342

Comparative Phenotypical and Molecular Analyses of Arabidopsis Grown under Fluorescent and LED Light

PubMed Central

Seiler, Franka; Soll, Jürgen; Bölter, Bettina

2017-01-01

Comparative analyses of phenotypic and molecular traits of Arabidopsis thaliana grown under standardised conditions is still a challenge using climatic devices supplied with common light sources. These are in most cases fluorescent lights, which have several disadvantages such as heat production at higher light intensities, an invariable spectral output, and relatively rapid “ageing”. This results in non-desired variations of growth conditions and lowers the comparability of data acquired over extended time periods. In this study, we investigated the growth behaviour of Arabidopsis Col0 under different light conditions, applying fluorescent compared to LED lamps, and we conducted physiological as well as gene expression analyses. By changing the spectral composition and/or light intensity of LEDs we can clearly influence the growth behaviour of Arabidopsis and thereby study phenotypic attributes under very specific light conditions that are stable and reproducible, which is not necessarily given for fluorescent lamps. By using LED lights, we can also roughly mimic the sun light emission spectrum, enabling us to study plant growth in a more natural-like light set-up. We observed distinct growth behaviour under the different light regimes which was reflected by physiological properties of the plants. In conclusion, LEDs provide variable emission spectra for studying plant growth under defined, stable light conditions. PMID:28608805

Performance of the mixed LED light quality on the growth and energy efficiency of Arthrospira platensis.

PubMed

Mao, Ruixin; Guo, Shuangsheng

2018-06-01

The effect of mixed light quality with red, blue, and green LED lamps on the growth of Arthrospira platensis was studied, so as to lay the theoretical and technical basis for establishing a photo-bioreactor lighting system for application in space. Meanwhile, indexes, like morphology, growth rate, photosynthetic pigment compositions, energy efficiency, and main nutritional components, were measured respectively. The results showed that the blue light combined with red light could decrease the tightness of filament, and the effect of green light was opposite. The combination of blue light or green light with red light induced the filaments to get shorter in length. The 8R2B treatment could promote the growth of Arthrospira platensis significantly, and its dry weight reached 1.36 g L -1 , which was 25.93% higher than the control. What's more, 8R2B treatment had the highest contents of carbohydrate and lipid, while 8R2G was rich in protein. 8R0.5G1.5B had the highest efficiency of biomass production, which was 161.53 mg L -1  kW -1  h -1 . Therefore, the combination of red and blue light is more conducive to the growth of Arthrospira platensis, and a higher biomass production and energy utilization efficiency can be achieved simultaneously under the mixed light quality with the ratio of 8R0.5G1.5B.

Frequency-Domain Optical Mammogram

DTIC Science & Technology

2002-10-01

have performed the proposed analysis of frequency-domain optical mammograms for a clinical population of about 150 patients. This analysis has led to...model the propagation of light in tissue14-20 have led to new approaches to optical mammography. As The authors are with the Department of Electrical...Modulation Methods, and Signal Detection /406 7.2.1 Lasers and arc lamps / 407’ 7.2.2 Pulsed sources / 407 7.2.3 Laser diodes and light-emitting diodes ( LEDs

Fundamental Characteristics of Deep-UV Light-Emitting Diodes and Their Application To Control Foodborne Pathogens.

PubMed

Shin, Joo-Yeon; Kim, Soo-Ji; Kim, Do-Kyun; Kang, Dong-Hyun

2016-01-01

Low-pressure mercury UV (LP-UV) lamps have long been used for bacterial inactivation, but due to certain disadvantages, such as the possibility of mercury leakage, deep-UV-C light-emitting diodes (DUV-LEDs) for disinfection have recently been of great interest as an alternative. Therefore, in this study, we examined the basic spectral properties of DUV-LEDs and the effects of UV-C irradiation for inactivating foodborne pathogens, including Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes, on solid media, as well as in water. As the temperature increased, DUV-LED light intensity decreased slightly, whereas LP-UV lamps showed increasing intensity until they reached a peak at around 30°C. As the irradiation dosage and temperature increased, E. coli O157:H7 and S. Typhimurium experienced 5- to 6-log-unit reductions. L. monocytogenes was reduced by over 5 log units at a dose of 1.67 mJ/cm(2). At 90% relative humidity (RH), only E. coli O157:H7 experienced inactivation significantly greater than at 30 and 60% RH. In a water treatment study involving a continuous system, 6.38-, 5.81-, and 3.47-log-unit reductions were achieved in E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, at 0.5 liter per minute (LPM) and 200 mW output power. The results of this study suggest that the use of DUV-LEDs may compensate for the drawbacks of using LP-UV lamps to inactivate foodborne pathogens. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Photodynamic therapy of HeLa cell cultures by using LED or laser sources.

PubMed

Etcheverry, María E; Pasquale, Miguel A; Garavaglia, Mario

2016-07-01

The photodynamic therapy (PDT) on HeLa cell cultures was performed utilizing a 637nm LED lamp with 1.06W power and m-tetrahydroxyphenyl chlorin (m-THPC) as photosensitizer and compared to a laser source emitting at 654nm with the same power. Intracellular placement of the photosensitizer and the effect of its concentration (CP), its absorption time (TA) and the illumination time (TI) were evaluated. It was observed that for CP>40μg/ml and TA>24h, m-THPC had toxicity on cells in culture, even in the absence of illumination. For the other tested concentrations, the cells remained viable if not subjected to illumination doses. No effect on cells was observed for CP<0.05μg/ml, TA=48h and TI=10min and they continued proliferating. For drug concentrations higher than 0.05μgml(-1), further deterioration is observed with increasing TA and TI. We evaluated the viability of the cells, before and after the treatment, and by supravital dyes, and phase contrast and fluorescence microscopies, evidence of different types of cell death was obtained. Tetrazolium dye assays after PDT during different times yielded similar results for the 637nm LED lamp with an illuminance three times greater than that of the 654nm laser source. Results demonstrate the feasibility of using a LED lamp as alternative to laser source. Here the main characteristic is not the light coherence but achieving a certain light fluence of the appropriate wavelength on cell cultures. We conclude that the efficacy was achieved satisfactorily and is essential for convenience, accessibility and safety. Copyright © 2016 Elsevier B.V. All rights reserved.

Dimming LEDs with Phase-Cut Dimmers. The Specifier's Process for Maximizing Success

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

Miller, N. J.; Poplawski, M. E.

2013-10-01

DOE GATEWAY program report reviewing how phase-cut dimmers work, how LEDs differ from the incandescent lamps these dimmers were originally designed to control, and how those differences can lead to complications when attempting to dim LEDs. Providing both general guidance and step-by-step procedures for designing phase-controlled LED dimming on both new and existing projects—as well as real-world examples of how to use those procedures—the report aims to reduce the chance of experiencing compatibility-related problems and, if possible, ensure good dimming performance.

Evaluation of photodynamic therapy using a light-emitting diode lamp against Enterococcus faecalis in extracted human teeth.

PubMed

Rios, Alejandro; He, Jianing; Glickman, Gerald N; Spears, Robert; Schneiderman, Emet D; Honeyman, Allen L

2011-06-01

Photodynamic therapy (PDT) with high-power lasers as the light source has been proven to be effective in disinfecting root canals. The aim of this study was to evaluate the antimicrobial effect of PDT using toluidine blue O (TBO) and a low-energy light-emitting diode (LED) lamp after the conventional disinfection protocol of 6% NaOCl. Single-rooted extracted teeth were cleaned, shaped, and sealed at the apex before incubation with Enterococcus faecalis for 2 weeks. Roots were randomly assigned to five experimental groups and three control groups. Dentin shavings were collected from the root canals of all groups with a #50/.06 rotary file, colony-forming units were determined, and the bacterial survival rate was calculated for each treatment. The bacterial survival rate of the NaOCl/TBO/light group (0.1%) was significantly lower (P < .005) than the NaOCl (0.66%) and TBO/light groups (2.9%). PDT using TBO and a LED lamp has the potential to be used as an adjunctive antimicrobial procedure in conventional endodontic therapy. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

LED Light Characteristics for Surgical Shadowless Lamps and Surgical Loupes

PubMed Central

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

2015-01-01

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

Miniature Incandescent Lamps as Fiber-Optic Light Sources

NASA Technical Reports Server (NTRS)

Tuma, Margaret; Collura, Joe; Helvajian, Henry; Pocha, Michael; Meyer, Glenn; McConaghy, Charles F.; Olsen, Barry L.

2008-01-01

Miniature incandescent lamps of a special type have been invented to satisfy a need for compact, rapid-response, rugged, broadband, power-efficient, fiber-optic-coupled light sources for diverse purposes that could include calibrating spectrometers, interrogating optical sensors, spot illumination, and spot heating.

Role of LAMP1 Binding and pH Sensing by the Spike Complex of Lassa Virus.

PubMed

Cohen-Dvashi, Hadas; Israeli, Hadar; Shani, Orly; Katz, Aliza; Diskin, Ron

2016-11-15

To effectively infect cells, Lassa virus needs to switch in an endosomal compartment from its primary receptor, α-dystroglycan, to a protein termed LAMP1. A unique histidine triad on the surface of the receptor-binding domain from the glycoprotein spike complex of Lassa virus is important for LAMP1 binding. Here we investigate mutated spikes that have an impaired ability to interact with LAMP1 and show that although LAMP1 is important for efficient infectivity, it is not required for spike-mediated membrane fusion per se Our studies reveal important regulatory roles for histidines from the triad in sensing acidic pH and preventing premature spike triggering. We further show that LAMP1 requires a positively charged His230 residue to engage with the spike complex and that LAMP1 binding promotes membrane fusion. These results elucidate the molecular role of LAMP1 binding during Lassa virus cell entry and provide new insights into how pH is sensed by the spike. Lassa virus is a devastating disease-causing agent in West Africa, with a significant yearly death toll and severe long-term complications associated with its infection in survivors. In recent years, we learned that Lassa virus needs to switch receptors in a pH-dependent manner to efficiently infect cells, but neither the molecular mechanisms that allow switching nor the actual effects of switching were known. Here we investigate the activity of the viral spike complex after abrogation of its ability to switch receptors. These studies inform us about the role of switching receptors and provide new insights into how the spike senses acidic pH. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

High intensity portable fluorescent light

NASA Technical Reports Server (NTRS)

Kendall, F. B.

1972-01-01

Eight high intensity portable fluorescent lights were produced. Three prototype lights were also produced, two of which were subsequently updated to the physical and operational configuration of the qualification and flight units. Positioning of lamp apertures and reflectors in these lights is such that the light is concentrated and intensified in a specific pattern rather than widely diffused. Indium amalgam control of mercury vapor pressure in the lamp gives high output at lamp ambient temperatures up to 105 C. A small amount of amalgam applied to each electrode stem helps to obtain fast warm-up. Shrinking a Teflon sleeve on the tube and potting metal caps on each end of the lamp minimizes dispersion of mercury vapor and glass particles in the event of accidental lamp breakage. Operation at 20 kHz allows the lamps to consume more power than at low frequency, thus increasing their light output and raising their efficiency. When used to expose color photographic film, light from the lamps produces results approximately equal to sunlight.

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

Dakin, J.

This talk is an overview of discharge lamp technology commonly employed in general lighting, with emphasis on issues pertinent to lighting for plant growth. Since the audience is primarily from the plant growth community, and this begins the light source part of the program, we will start with a brief description of the discharge lamps. Challenges of economics and of thermal management make lamp efficiency a prime concern in controlled environment agriculture, so we will emphasize science considerations relating to discharge lamp efficiency. We will then look at the spectra and ratings of some representative lighting products, and conclude withmore » a discussion of technological advance. A general overview of discharge lighting technology can be found in the book of Waymouth (1971). A recent review of low pressure lighting discharge science is found in Dakin (1991). The pioneering paper of Reiling (1964) provides a good introduction to metal halide discharges. Particularly relevant to lighting for plant growth, a recent and thorough treatment of high pressure Na lamps is found in the book by deGroot and vanVliet (1986). Broad practical aspects of lighting application are thoroughly covered in the IES Lighting Handbook edited by Kaufman (1984).« less

Immunocapture loop-mediated isothermal amplification assays for the detection of canine parvovirus.

PubMed

Sun, Yu-Ling; Yen, Chon-Ho; Tu, Ching-Fu

2017-11-01

A loop-mediated isothermal amplification (LAMP) assay was used for rapid canine parvovirus (CPV) diagnosis. To reduce the time required and increase the sensitivity of the assay, an immunocapture (IC) technique was developed in this study to exclude the DNA extraction step in molecular diagnostic procedures for CPV. A polyclonal rabbit anti-CPV serum was produced against VP2-EpC that was cloned via DNA recombination. The polyclonal anti-VP2-EpC serum was used for virus capture to prepare microtubes. IC-LAMP was performed to amplify a specific CPV target gene sequence from the CPV viral particles that were captured on the microtubes, and the amplicons were analyzed using agarose electrophoresis or enzyme-linked immunosorbent assay (IC-LAMP-ELISA) and lateral-flow dipstick (IC-LAMP-LFD). The detection sensitivities of IC-LAMP, IC-LAMP-ELISA, and IC-LAMP-LFD were 10 -1 , 10 -1 , and 10 -1 TCID 50 /mL, respectively. Using the IC-LAMP-ELISA and IC-LAMP-LFD assays, the complete CPV diagnostic process can be achieved within 1.5h. Both of the developed IC-LAMP-based assays are simple, direct visual and efficient techniques that are applicable to the detection of CPV. Copyright © 2017 Elsevier B.V. All rights reserved.

Fabrication of full-color GaN-based light-emitting diodes on nearly lattice-matched flexible metal foils.

PubMed

Kim, Hyeryun; Ohta, Jitsuo; Ueno, Kohei; Kobayashi, Atsushi; Morita, Mari; Tokumoto, Yuki; Fujioka, Hiroshi

2017-05-18

GaN-based light-emitting diodes (LEDs) have been widely accepted as highly efficient solid-state light sources capable of replacing conventional incandescent and fluorescent lamps. However, their applications are limited to small devices because their fabrication process is expensive as it involves epitaxial growth of GaN by metal-organic chemical vapor deposition (MOCVD) on single crystalline sapphire wafers. If a low-cost epitaxial growth process such as sputtering on a metal foil can be used, it will be possible to fabricate large-area and flexible GaN-based light-emitting displays. Here we report preparation of GaN films on nearly lattice-matched flexible Hf foils using pulsed sputtering deposition (PSD) and demonstrate feasibility of fabricating full-color GaN-based LEDs. It was found that introduction of low-temperature (LT) grown layers suppressed the interfacial reaction between GaN and Hf, allowing the growth of high-quality GaN films on Hf foils. We fabricated blue, green, and red LEDs on Hf foils and confirmed their normal operation. The present results indicate that GaN films on Hf foils have potential applications in fabrication of future large-area flexible GaN-based optoelectronics.

New illuminations approaches with single-use micro LEDs endoilluminators for the pars plana vitrectomy

NASA Astrophysics Data System (ADS)

Koelbl, Philipp Simon; Koch, Frank H. J.; Lingenfelder, Christian; Hessling, Martin

2018-02-01

The illumination of the intraocular space during pars plana vitrectomy always bears the risk of retina damage by irradiation. Conventional illumination systems consist of an external light source and an optical fiber to transfer the visible light (radiation) into the eye. Often xenon arc and halogen lamps are employed for this application with some disadvantageous properties like high phototoxicity and low efficiency. Therefore, we propose to generate the light directly within the eye by inserting a white micro LED with a diameter of 0.6 mm. The LED offers a luminous flux of 0.6 lm of white light with a blue peak @ 450 nm and a yellow peak @ 555 nm. The presented prototypes fit through a standard 23 G trocar and are the first intraocular light sources worldwide. Two different single-use approaches have already been developed: a handguided and a chandelier device. The hand-guided applicator enables a directly navigation and illumination up to a working distance of 6 mm. The chandelier device is much smaller and does not need an active navigation of the light cone. The brightness and homogeneity of the illumination of these LED devices have been successfully tested on porcine eyes. Presented measurements and calculations prove that even for high LED currents and small distances to the retina these intraocular micro LED devices expose the retina to less hazard than conventional illumination sources like fiber based xenon systems. Even under the worst circumstances application durations of 180 hours would be justifiable.

Photovoltaic Experiment Using Light from a Solar Simulator Lamp.

ERIC Educational Resources Information Center

Chow, R. H.

1980-01-01

A photovoltaic cell experiment utilizing the convenience of a solar simulating type lamp is described. Insight into the solid state aspect of a solar cell is gained by the student in studying the characteristics, and deducing from them cell parameters and efficiency. (Author/CS)

An LED solar simulator for student labs

NASA Astrophysics Data System (ADS)

González, Manuel I.

2017-05-01

Measuring voltage-current and voltage-power curves of a photovoltaic module is a nice experiment for high school and undergraduate students. In labs where real sunlight is not available this experiment requires a solar simulator. A prototype of a simulator using LED lamps has been manufactured and tested, and a comparison with classical halogen simulators has been performed. It is found that LED light offers lower levels of irradiance, but much better performance in terms of module output for a given irradiance.

Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: a modular vacuum ultraviolet source.

PubMed

Roberts, F Sloan; Anderson, Scott L

2013-12-01

The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a "soft" photoionization source for gas-phase mass spectrometry.

Effectiveness of recycling light in ultra-bright short-arc discharge lamps.

PubMed

Malul, Asher; Nakar, Doron; Feuermann, Daniel; Gordon, Jeffrey M

2007-10-17

Recycling light back into a plasma lamp's radiant zone can enhance its radiance. Measurements are reported for the effectiveness, spectral properties and modified plasma radiance maps that result from light recycling with a specular hemispherical mirror in commercial 150 W ultrabright Xenon short-arc discharge lamps, motivated by projection, biomedical and high-temperature furnace applications. For certain spectral windows and plasma arc regions, radiance can be heightened by up to 70%. However, the overall light recycling efficiency is reduced to about half this value due to lamp geometry. The manner in which light-plasma interactions affect light recycling efficacy is also elucidated.

Environmental impacts of lighting technologies - Life cycle assessment and sensitivity analysis

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

Welz, Tobias; Hischier, Roland, E-mail: Roland.Hischier@empa.ch; Hilty, Lorenz M.

2011-04-15

With two regulations, 244/2009 and 245/2009, the European Commission recently put into practice the EuP Directive in the area of lighting devices, aiming to improve energy efficiency in the domestic lighting sector. This article presents a comprehensive life cycle assessment comparison of four different lighting technologies: the tungsten lamp, the halogen lamp, the conventional fluorescent lamp and the compact fluorescent lamp. Taking advantage of the most up-to-date life cycle inventory database available (ecoinvent data version 2.01), all life cycle phases were assessed and the sensitivity of the results for varying assumptions analysed: different qualities of compact fluorescent lamps (production phase),more » different electricity mixes (use phase), and end-of-life scenarios for WEEE recycling versus municipal solid waste incineration (disposal phase). A functional unit of 'one hour of lighting' was defined and the environmental burdens for the whole life cycle for all four lamp types were calculated, showing a clearly lower impact for the two gas-discharge lamps, i.e. the fluorescent and the compact fluorescent lamp. Differences in the product quality of the compact fluorescent lamps reveal to have only a very small effect on the overall environmental performance of this lamp type; a decline of the actual life time of this lamp type doesn't result in a change of the rank order of the results of the here examined four lamp types. It was also shown that the environmental break-even point of the gas-discharge lamps is reached long before the end of their expected life-span. All in all, it can be concluded that a change from today's tungsten lamp technology to a low-energy-consuming technology such as the compact fluorescent lamp results in a substantial environmental benefit.« less

EDITORIAL: Mercury-free discharges for lighting

NASA Astrophysics Data System (ADS)

Haverlag, M.

2007-07-01

This special Cluster of articles in Journal of Physics D: Applied Physics covers the subject of mercury-free discharges that are being investigated by different light source researchers, as an alternative to existing mercury-containing lamps. The main driving force to move away from mercury-containing discharge light sources is connected to the environmentally unfriendly nature of mercury. After inhalation or direct contact, severe mercury exposure can lead to damage to human brain cells, the kidneys, the liver and the nervous system. For this reason, the use of mercury in products is becoming more and more restricted by different governmental bodies. In the lighting industry, however, many products still make use of mercury, for different reasons. The main reason is that mercury-containing products are, in most cases, more efficient than mercury-free products. For a realistic comparison of the environmental impact, the mercury-contamination due to electricity production must be taken into account, which depends on the type of fuel being used. For an average European fuel-mix, the amount of mercury that is released into the environment is around 29 μg kWh-1. This means that a typical 30 W TL lamp during a lifetime of 20,000 hours will release a total of about 20 mg mercury due to electricity production, which exceeds the total mercury dose in the lamp (more and more of which is being recycled) by a factor of 5-10 for a modern TL lamp. This illustrates that, quite apart from other environmental arguments like increased CO2 production, mercury-free alternatives that use more energy can in fact be detrimental for the total mercury pollution over the lifetime of the lamp. For this reason, the lighting industry has concentrated on lowering the mercury content in lamps as long as no efficient alternatives exist. Nevertheless, new initiatives for HID lamps and fluorescent lamps with more or less equal efficiency are underway, and a number of them are described in this special issue. These initiatives may in time offer realistic alternatives for mercury-containing discharge lamps as the efficiency gap with existing products is getting smaller. At the same time, new applications for radiation sources are becoming more important, and in some of them the presence of mercury has other disadvantages besides the environmental aspects. Since in most cases mercury is used in the form of a saturated vapour, the mercury pressure is dependent on the ambient temperature, which means that mercury-containing lamps often show a slow increase to the steady-state light output or a strongly reduced output in cold environments, which is undesirable in many applications. For this reason also, different options for light sources without mercury are being investigated, and a number of them can be found in this special issue. This collection of papers gives a good overview of the different technologies that are currently being investigated as alternatives to existing lamp technologies, and will surely inspire others to reduce the use of mercury for lighting applications.

The effect of the polymerization initiator and light source on the elution of residual Bis-GMA and TEGDMA monomers: A study using liquid chromatography with UV detection.

PubMed

Denis, Aline B; Diagone, Cristina A; Plepis, Ana M G; Viana, Rommel B

2015-12-05

A method for the extraction and quantification of two residual monomers, bisphenol glycidyl dimethacrylate (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA), that were evaluated using high efficiency liquid chromatography with UV detection was developed and validated in this study. Three types of solvents were applied in the extraction of the monomers (methanol, ethanol and acetonitrile), where the highest extraction efficiency was obtained using acetonitrile. The different resins were prepared by photoactivation of Bis-GMA and TEGDMA monomers. Additionally, the effects of the addition of two photoinitiators (camphorquinone (CQ) and phenyl propanodione (PPD) and that of a co-initiator (N,N-dimethyl-p-toluidine) were also analyzed. When only the CQ photoinitiator was used, a smaller amount of residual monomers was obtained, whereas a larger amount was obtained with PPD. When the two photoinitiators were used in the same matrix, however, no significant changes were observed in relation to the amount of residual TEGDMA monomers. For the addition of the co-initiator, there were no large changes in the extraction of residual monomers. The effect of the two photoactivation sources (halogen lamp and LED) led to small differences in the elution of the two monomers, although all of the resins differed significantly when photoactivated with a LED. Quantum chemical calculations using Density Functional Theory were carried out to characterize several molecular properties of each monomer. Copyright © 2015 Elsevier B.V. All rights reserved.

Response of conifer species from three latitudinal populations to light spectra generated by light-emitting diodes and high-pressure sodium lamps

Treesearch

Kent G. Apostol; Kas Dumroese; Jeremy Pinto; Anthony S. Davis

2015-01-01

Light-emitting diode (LED) technology shows promise for supplementing photosynthetically active radiation (PAR) in forest nurseries because of the potential reduction in energy consumption and an ability to supply discrete wavelengths to optimize seedling growth. Our objective was to examine the effects of light spectra supplied by LED and traditional high-pressure...

Next Generation Lighting Technologies (LBNL Summer Lecture Series)

ScienceCinema

Siminovittch, Micheal

2018-04-27

For the past several years, Michael Siminovittch, a researcher in the Environmental Energy Technologies Division of Lawrence Berkeley National Laboratory, has worked to package efficient lighting in an easy-to-use and good-looking lamp. His immensely popular "Berkeley Lamp" has redefined how America lights its offices.

Detailed Balance Limit of Efficiency of Broadband-Pumped Lasers.

PubMed

Nechayev, Sergey; Rotschild, Carmel

2017-09-13

Broadband light sources are a wide class of pumping schemes for lasers including LEDs, sunlight and flash lamps. Recently, efficient coupling of broadband light to high-quality micro-cavities has been demonstrated for on-chip applications and low-threshold solar-pumped lasers via cascade energy transfer. However, the conversion of incoherent to coherent light comes with an inherent price of reduced efficiency, which has yet to be assessed. In this paper, we derive the detailed balance limit of efficiency of broadband-pumped lasers and discuss how it is affected by the need to maintain a threshold population inversion and thermodynamically dictated minimal Stokes' shift. We show that lasers' slope efficiency is analogous to the nominal efficiency of solar cells, limited by thermalisation losses and additional unavoidable Stokes' shift. The lasers' power efficiency is analogous to the detailed balance limit of efficiency of solar cells, affected by the cavity mirrors and impedance matching factor, respectively. As an example we analyze the specific case of solar-pumped sensitized Nd 3+ :YAG-like lasers and define the conditions to reach their thermodynamic limit of efficiency. Our work establishes an upper theoretical limit for the efficiency of broadband-pumped lasers. Our general, yet flexible model also provides a way to incorporate other optical and thermodynamic losses and, hence, to estimate the efficiency of non-ideal broadband-pumped lasers.

Mechanistic evaluation of the pros and cons of digital RT-LAMP for HIV-1 viral load quantification on a microfluidic device and improved efficiency via a two-step digital protocol.

PubMed

Sun, Bing; Shen, Feng; McCalla, Stephanie E; Kreutz, Jason E; Karymov, Mikhail A; Ismagilov, Rustem F

2013-02-05

Here we used a SlipChip microfluidic device to evaluate the performance of digital reverse transcription-loop-mediated isothermal amplification (dRT-LAMP) for quantification of HIV viral RNA. Tests are needed for monitoring HIV viral load to control the emergence of drug resistance and to diagnose acute HIV infections. In resource-limited settings, in vitro measurement of HIV viral load in a simple format is especially needed, and single-molecule counting using a digital format could provide a potential solution. We showed here that when one-step dRT-LAMP is used for quantification of HIV RNA, the digital count is lower than expected and is limited by the yield of desired cDNA. We were able to overcome the limitations by developing a microfluidic protocol to manipulate many single molecules in parallel through a two-step digital process. In the first step we compartmentalize the individual RNA molecules (based on Poisson statistics) and perform reverse transcription on each RNA molecule independently to produce DNA. In the second step, we perform the LAMP amplification on all individual DNA molecules in parallel. Using this new protocol, we increased the absolute efficiency (the ratio between the concentration calculated from the actual count and the expected concentration) of dRT-LAMP 10-fold, from ∼2% to ∼23%, by (i) using a more efficient reverse transcriptase, (ii) introducing RNase H to break up the DNA:RNA hybrid, and (iii) adding only the BIP primer during the RT step. We also used this two-step method to quantify HIV RNA purified from four patient samples and found that in some cases, the quantification results were highly sensitive to the sequence of the patient's HIV RNA. We learned the following three lessons from this work: (i) digital amplification technologies, including dLAMP and dPCR, may give adequate dilution curves and yet have low efficiency, thereby providing quantification values that underestimate the true concentration. Careful validation is essential before a method is considered to provide absolute quantification; (ii) the sensitivity of dLAMP to the sequence of the target nucleic acid necessitates additional validation with patient samples carrying the full spectrum of mutations; (iii) for multistep digital amplification chemistries, such as a combination of reverse transcription with amplification, microfluidic devices may be used to decouple these steps from one another and to perform them under different, individually optimized conditions for improved efficiency.

Interpretation of digital chest radiographs: comparison of light emitting diode versus cold cathode fluorescent lamp backlit monitors.

PubMed

Lim, Hyun-ju; Chung, Myung Jin; Lee, Geewon; Yie, Miyeon; Shin, Kyung Eun; Moon, Jung Won; Lee, Kyung Soo

2013-01-01

To compare the diagnostic performance of light emitting diode (LED) backlight monitors and cold cathode fluorescent lamp (CCFL) monitors for the interpretation of digital chest radiographs. We selected 130 chest radiographs from health screening patients. The soft copy image data were randomly sorted and displayed on a 3.5 M LED (2560 × 1440 pixels) monitor and a 3 M CCFL (2048 × 1536 pixels) monitor. Eight radiologists rated their confidence in detecting nodules and abnormal interstitial lung markings (ILD). Low dose chest CT images were used as a reference standard. The performance of the monitor systems was assessed by analyzing 2080 observations and comparing them by multi-reader, multi-case receiver operating characteristic analysis. The observers reported visual fatigue and a sense of heat. Radiant heat and brightness of the monitors were measured. Measured brightness was 291 cd/m(2) for the LED and 354 cd/m(2) for the CCFL monitor. Area under curves for nodule detection were 0.721 ± 0.072 and 0.764 ± 0.098 for LED and CCFL (p = 0.173), whereas those for ILD were 0.871 ± 0.073 and 0.844 ± 0.068 (p = 0.145), respectively. There were no significant differences in interpretation time (p = 0.446) or fatigue score (p = 0.102) between the two monitors. Sense of heat was lower for the LED monitor (p = 0.024). The temperature elevation was 6.7℃ for LED and 12.4℃ for the CCFL monitor. Although the LED monitor had lower maximum brightness compared with the CCFL monitor, soft copy reading of the digital chest radiographs on LED and CCFL showed no difference in terms of diagnostic performance. In addition, LED emitted less heat.

10 CFR 429.54 - Metal halide lamp ballasts and fixtures.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Metal halide lamp ballasts and fixtures. 429.54 Section 429.54 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR... and tested to ensure that: (i) Any represented value of estimated energy efficiency calculated as the...

10 CFR 429.54 - Metal halide lamp ballasts and fixtures.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Metal halide lamp ballasts and fixtures. 429.54 Section 429.54 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR... and tested to ensure that: (i) Any represented value of estimated energy efficiency calculated as the...

10 CFR 429.54 - Metal halide lamp ballasts and fixtures.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Metal halide lamp ballasts and fixtures. 429.54 Section 429.54 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR... and tested to ensure that: (i) Any represented value of estimated energy efficiency calculated as the...

10 CFR 431.323 - Materials incorporated by reference.

Code of Federal Regulations, 2011 CFR

2011-01-01

... of Energy, Office of Energy Efficiency and Renewable Energy, Building Technologies Program, 6th Floor... National Standard for electric lamps: Single-Ended Metal Halide Lamps, approved May 5, 2004, IBR approved... (“NFPA 70”), National Electrical Code 2002 Edition, IBR approved for § 431.326; (2) [Reserved] (e) UL...

10 CFR 431.323 - Materials incorporated by reference.

Code of Federal Regulations, 2013 CFR

2013-01-01

... of Energy, Office of Energy Efficiency and Renewable Energy, Building Technologies Program, 6th Floor... National Standard for electric lamps: Single-Ended Metal Halide Lamps, approved May 5, 2004, IBR approved... (“NFPA 70”), National Electrical Code 2002 Edition, IBR approved for § 431.326; (2) [Reserved] (e) UL...

77 FR 18963 - Energy Conservation Program: Public Meeting and Availability of the Framework Document for High...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-29

... the Framework Document for High-Intensity Discharge Lamps AGENCY: Office of Energy Efficiency and... availability of framework document for high-intensity discharge (HID) lamps, initiating the rulemaking and data... Availability of Framework Document Regarding Energy Conservation Standards for High-Intensity Discharge (HID...

Halogen lamp and LED activation of resin-modified glass ionomer restorative material. In vitro microhardness after long-term storage.

PubMed

Cassoni, A; Macarini, P; Leonetti, E S; Shibli, J A; Rodrigues, J A

2011-09-01

The purpose of this study was to evaluate the activation of resin-modified glass ionomer restorative material (RMGI, Vitremer-3M-ESPE, A3) by halogen lamp (QTH) or light-emitting diode (LED) by Knoop microhardness (KHN) in two storage conditions: 24 hrs and 6 months and in two depths (0 and 2 mm). The specimens were randomly divided into 3 experimental groups (n = 10) according to activation form and evaluated in depth after 24 h and after 6 months of storage. Activation was performed with QTH for 40s (700 mW/cm) and for 40 or 20 s with LED (1,200 mW/cm2). After 24 hrs and 6 months of storage at 37 degrees C in relative humidity in light-proof container, the Knoop microhardness test was performed. Statistics Data were analysed by three-way ANOVA and Tukey post-tests (p < 0.05). All evaluated factors showed significant differences (p < 0.05). After 24 hrs there were no differences within the experimental groups. KHN at 0 mm was significantly higher than 2 mm. After 6 months, there was an increase of microhardness values for all groups, being the ones activated by LED higher than the ones activated by QTH. Light-activation with LED positively influenced the KHN for RMGI evaluated after 6 months.

Rapid authentication of the precious herb saffron by loop-mediated isothermal amplification (LAMP) based on internal transcribed spacer 2 (ITS2) sequence

PubMed Central

Zhao, Mingming; Shi, Yuhua; Wu, Lan; Guo, Licheng; Liu, Wei; Xiong, Chao; Yan, Song; Sun, Wei; Chen, Shilin

2016-01-01

Saffron is one of the most expensive species of Chinese herbs and has been subjected to various types of adulteration because of its high price and limited production. The present study introduces a loop-mediated isothermal amplification (LAMP) technique for the differentiation of saffron from its adulterants. This novel technique is sensitive, efficient and simple. Six specific LAMP primers were designed on the basis of the nucleotide sequence of the internal transcribed spacer 2 (ITS2) nuclear ribosomal DNA of Crocus sativus. All LAMP amplifications were performed successfully, and visual detection occurred within 60 min at isothermal conditions of 65 °C. The results indicated that the LAMP primers are accurate and highly specific for the discrimination of saffron from its adulterants. In particular, 10 fg of genomic DNA was determined to be the limit for template accuracy of LAMP in saffron. Thus, the proposed novel, simple, and sensitive LAMP assay is well suited for immediate on-site discrimination of herbal materials. Based on the study, a practical standard operating procedure (SOP) for utilizing the LAMP protocol for herbal authentication is provided. PMID:27146605

Rapid authentication of the precious herb saffron by loop-mediated isothermal amplification (LAMP) based on internal transcribed spacer 2 (ITS2) sequence.

PubMed

Zhao, Mingming; Shi, Yuhua; Wu, Lan; Guo, Licheng; Liu, Wei; Xiong, Chao; Yan, Song; Sun, Wei; Chen, Shilin

2016-05-05

Saffron is one of the most expensive species of Chinese herbs and has been subjected to various types of adulteration because of its high price and limited production. The present study introduces a loop-mediated isothermal amplification (LAMP) technique for the differentiation of saffron from its adulterants. This novel technique is sensitive, efficient and simple. Six specific LAMP primers were designed on the basis of the nucleotide sequence of the internal transcribed spacer 2 (ITS2) nuclear ribosomal DNA of Crocus sativus. All LAMP amplifications were performed successfully, and visual detection occurred within 60 min at isothermal conditions of 65 °C. The results indicated that the LAMP primers are accurate and highly specific for the discrimination of saffron from its adulterants. In particular, 10 fg of genomic DNA was determined to be the limit for template accuracy of LAMP in saffron. Thus, the proposed novel, simple, and sensitive LAMP assay is well suited for immediate on-site discrimination of herbal materials. Based on the study, a practical standard operating procedure (SOP) for utilizing the LAMP protocol for herbal authentication is provided.

Systematic review: Comparison of Xpert MTB/RIF, LAMP and SAT methods for the diagnosis of pulmonary tuberculosis.

PubMed

Yan, Liping; Xiao, Heping; Zhang, Qing

2016-01-01

Technological advances in nucleic acid amplification have led to breakthroughs in the early detection of PTB compared to traditional sputum smear tests. The sensitivity and specificity of loop-mediated isothermal amplification (LAMP), simultaneous amplification testing (SAT), and Xpert MTB/RIF for the diagnosis of pulmonary tuberculosis were evaluated. A critical review of previous studies of LAMP, SAT, and Xpert MTB/RIF for the diagnosis of pulmonary tuberculosis that used laboratory culturing as the reference method was carried out together with a meta-analysis. In 25 previous studies, the pooled sensitivity and specificity of the diagnosis of tuberculosis were 93% and 94% for LAMP, 96% and 88% for SAT, and 89% and 98% for Xpert MTB/RIF. The I(2) values for the pooled data were >80%, indicating significant heterogeneity. In the smear-positive subgroup analysis of LAMP, the sensitivity increased from 93% to 98% (I(2) = 2.6%), and specificity was 68% (I(2) = 38.4%). In the HIV-infected subgroup analysis of Xpert MTB/RIF, the pooled sensitivity and specificity were 79% (I(2) = 72.9%) and 99% (I(2) = 64.4%). In the HIV-negative subgroup analysis for Xpert MTB/RIF, the pooled sensitivity and specificity were 72% (I(2) = 49.6%) and 99% (I(2) = 64.5%). LAMP, SAT and Xpert MTB/RIF had comparably high levels of sensitivity and specificity for the diagnosis of tuberculosis. The diagnostic sensitivity and specificity of three methods were similar, with LAMP being highly sensitive for the diagnosis of smear-positive PTB. The cost effectiveness of LAMP and SAT make them particularly suitable tests for diagnosing PTB in developing countries. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dominant transverse-electric polarized emission from 298 nm MBE-grown AlN-delta-GaN quantum well ultraviolet light-emitting diodes

NASA Astrophysics Data System (ADS)

Liu, Cheng; Ooi, Yu Kee; Islam, S. M.; Xing, Huili Grace; Jena, Debdeep; Zhang, Jing

2017-02-01

III-nitride based ultraviolet (UV) light emitting diodes (LEDs) are of considerable interest in replacing gas lasers and mercury lamps for numerous applications. Specifically, AlGaN quantum well (QW) based LEDs have been developed extensively but the external quantum efficiencies of which remain less than 10% for wavelengths <300 nm due to high dislocation density, difficult p-type doping and most importantly, the physics and band structure from the three degeneration valence subbands. One solution to address this issue at deep UV wavelengths is by the use of the AlGaN-delta-GaN QW where the insertion of the delta-GaN layer can ensure the dominant conduction band (C) - heavyhole (HH) transition, leading to large transverse-electric (TE) optical output. Here, we proposed and investigated the physics and polarization-dependent optical characterizations of AlN-delta- GaN QW UV LED at 300 nm. The LED structure is grown by Molecular Beam Epitaxy (MBE) where the delta-GaN layer is 3-4 monolayer (QW-like) sandwiched by 2.5-nm AlN sub-QW layers. The physics analysis shows that the use of AlN-delta-GaN QW ensures a larger separation between the top HH subband and lower-energy bands, and strongly localizes the electron and HH wave functions toward the QW center and hence resulting in 30-time enhancement in TEpolarized spontaneous emission rate, compared to that of a conventional Al0.35Ga0.65N QW. The polarization-dependent electroluminescence measurements confirm our theoretical analysis; a dominant TE-polarized emission was obtained at 298 nm with a minimum transverse-magnetic (TM) polarized emission, indicating the feasibility of high-efficiency TEpolarized UV emitters based on our proposed QW structure.

Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: A modular vacuum ultraviolet source

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

Sloan Roberts, F.; Anderson, Scott L.

2013-12-15

The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a “soft” photoionization source for gas-phase massmore » spectrometry.« less

Polymerization of a dual-cured cement through ceramic: LED curing light vs halogen lamp.

PubMed

Lopes, Lawrence Gonzaga; Franco, Eduardo Batista; Name Neto, Abrão; Herrera, Francyle S; Kurachi, Cristina; Castañeda-Espinosa, Juan C; Lauris, José Roberto Pereira

2004-12-01

The aim of this study was to investigate the influence of light source, LED unit and halogen lamp (HL), on the effectiveness of Enforce dual-cured cement cured under a ceramic disc. Three exposure times (60, 80 and 120 s) were also evaluated. Two experimental groups, in which the polymerization of the dual-cured cement was performed through a ceramic disc, and two control groups, in which the polymerization of the dual-cured cement was performed directly without presence of ceramic disc were subdivided into three subgroups (three different exposure times), with five specimens each: G1A- HL 60s; G1B- HL 80s; G1C- HL 120s; G2A- LED 60s; G2B- LED 80s; G2C- LED 120s; and control groups: G3A- HL 60s; G3B- HL 80s; G3C- HL 120s; G4A- LED 60s; G4B- LED 80s and G4C- LED 120s. Cement was applied in a steel matrix (4mm diameter, 1.2mm thickness). In the experimental groups, a ceramic disc was placed on top. The cement was light-cured through the ceramic by a HL and LED, however, the control groups were cured without the ceramic disc. The specimens were stored in a light-proof container at 37ºC for 24 hours, then Vickers hardness was determined. A four-way ANOVA and Tukey test (p£ 0.05) were performed. All specimens cured by LED for 60s showed inferior values compared with the halogen groups. In general, light-curing by LED for 80s and 120s was comparable to halogen groups (60s and 80s) and their control groups. LED technology can be viable for light-curing through conventional ceramic indirect restorations, when curing time is increased in relation to HL curing time.

Using light emitting diodes in traffic signals : final report.

DOT National Transportation Integrated Search

1998-07-01

In 1993, the Oregon Department of Transportation (ODOT) began testing red light emitting diodes (LED's) as a replacement to the incandescent lamps in vehicular and pedestrian signals. Field performance was found to be reliable and subsequently ODOT b...

78 FR 13756 - Technical Report: Effectiveness of LED Stop Lamps for Reducing Rear-End Crashes: Analyses of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-28

...) using real-world crash data. Previous work on this subject included laboratory experiments that suggest... pairs. Procedural Matters How can I influence NHTSA's thinking on this subject? NHTSA welcomes public...

Rapid specific and visible detection of porcine circovirus type 3 using loop-mediated isothermal amplification (LAMP).

PubMed

Zheng, S; Wu, X; Shi, J; Peng, Z; Gao, M; Xin, C; Liu, Y; Wang, S; Xu, S; Han, H; Yu, J; Sun, W; Cong, X; Li, J; Wang, J

2018-06-01

In this study, a rapid and specific assay for the detection of porcine circovirus type 3 (PCV3) was established using loop-mediated isothermal amplification (LAMP). Four primers were specifically designed to amplify PCV3. The LAMP assay was effectively optimized to amplify PCV3 by water bath at 60°C for 60 min. The detection limit was approximately 1 × 10 1 copy in this LAMP assay. Compared to porcine circovirus type 2 (PCV2), both gE and gD genes of pseudorabies virus (PRV) and porcine parvovirus (PPV), the LAMP assay showed a high specific detection of PCV3. A visible detection method was developed using SYBR Green I to recognize the results rapidly. Based on the detection of 20 clinical tissue samples, the LAMP assay was more practical and convenient than classical PCR due to its simplicity, high sensitivity, rapidity, specificity, visibility and cost efficiency. © 2018 Blackwell Verlag GmbH.

Direct electron-impact mechanism of excitation of mercury monobromide in a double-pulse dielectric-barrier-discharge HgBr lamp

NASA Astrophysics Data System (ADS)

Datsyuk, V. V.; Izmailov, I. A.; Naumov, V. V.; Kochelap, V. A.

2016-08-01

In a nonequlibrium plasma of a gas-discharge HgBr lamp, the terminal electronic state of the HgBr(B-X) radiative transition with a peak wavelength of 502 nm remains populated for a relatively long time and is repeatedly excited to the B state in collisions with plasma electrons. This transfer of the HgBr molecules from the ground state X to the excited state B is the main mechanism of formation of the light-emitting molecules especially when the lamp is excited by double current pulses. According to our simulations, due to the electron-induced transitions between HgBr(X) and HgBr(B), the output characteristics of the DBD lamp operating in a double-pulse regime are better than those of the lamp operating in a single-pulse regime. In the considered case, the peak power is calculated to increase by a factor of about 2 and the lamp efficiency increases by about 50%.

A novel loop-mediated isothermal amplification-based test for detecting Neospora caninum DNA.

PubMed

Ramos, Andrea Estefanía; Muñoz, Marina; Cortés-Vecino, Jesús Alfredo; Barato, Paola; Patarroyo, Manuel Alfonso

2017-11-29

Neospora caninum is a cyst-forming, coccidian parasite which is known to cause neurological disorders in dogs and abortion and neonatal mortality in cows and other livestock. This study reports the development of a loop-mediated isothermal amplification (LAMP) assay based on the Neospora caninum Nc-5 gene and compares its efficacy for detecting DNA to that of a semi-nested PCR test. Six primers were designed based on the Nc-5 repeat region of N. caninum. Specific LAMP primers led to successful amplification of N. caninum DNA at 63 °C in 30 min. The LAMP assay was highly specific (i.e. it did not reveal cross-reactivity with other parasite species) and had a low N. caninum plasmid DNA limit of detection (1 fg), which is ten times higher than that for the semi-nested PCR. LAMP applicability was evaluated using a set of naturally-infected samples (59 from canine faeces and five from bovine abortions). Thirty-nine percent (25/64) of the naturally-infected samples were positive for N. caninum DNA by LAMP and 36% (23/64) by semi-nested PCR. However, the LAMP assay is much faster to perform than semi-nested PCR and provides results in 30 min. The optimized reaction conditions described in this study resulted in a sensitive, specific and rapid technique for detecting N. caninum DNA. Considering the advantages of LAMP for detecting N. caninum DNA, further assays aimed at testing its usefulness on a wider range of field samples are recommended.

High-Brightness Blue Light-Emitting Diodes Enabled by a Directly Grown Graphene Buffer Layer.

PubMed

Chen, Zhaolong; Zhang, Xiang; Dou, Zhipeng; Wei, Tongbo; Liu, Zhiqiang; Qi, Yue; Ci, Haina; Wang, Yunyu; Li, Yang; Chang, Hongliang; Yan, Jianchang; Yang, Shenyuan; Zhang, Yanfeng; Wang, Junxi; Gao, Peng; Li, Jinmin; Liu, Zhongfan

2018-06-08

Single-crystalline GaN-based light-emitting diodes (LEDs) with high efficiency and long lifetime are the most promising solid-state lighting source compared with conventional incandescent and fluorescent lamps. However, the lattice and thermal mismatch between GaN and sapphire substrate always induces high stress and high density of dislocations and thus degrades the performance of LEDs. Here, the growth of high-quality GaN with low stress and a low density of dislocations on graphene (Gr) buffered sapphire substrate is reported for high-brightness blue LEDs. Gr films are directly grown on sapphire substrate to avoid the tedious transfer process and GaN is grown by metal-organic chemical vapor deposition (MOCVD). The introduced Gr buffer layer greatly releases biaxial stress and reduces the density of dislocations in GaN film and In x Ga 1- x N/GaN multiple quantum well structures. The as-fabricated LED devices therefore deliver much higher light output power compared to that on a bare sapphire substrate, which even outperforms the mature process derived counterpart. The GaN growth on Gr buffered sapphire only requires one-step growth, which largely shortens the MOCVD growth time. This facile strategy may pave a new way for applications of Gr films and bring several disruptive technologies for epitaxial growth of GaN film and its applications in high-brightness LEDs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

10 CFR Appendix A to Subpart S of... - Compliance Statement for Metal Halide Lamp Ballasts

Code of Federal Regulations, 2011 CFR

2011-01-01

... Equipment: Metal Halide Lamp Ballasts Manufacturer's or Private Labeler's Name and Address: [Company name] (“the company”) submits this Compliance Statement under 10 CFR Part 431 (Energy Efficiency Program for... Reports submitted by or on behalf of this company. All information in such Certification Report(s) and in...

Development of a novel loop-mediated isothermal amplification (LAMP) assay for the detection of Salmonella ser. Enteritidis from egg products

USDA-ARS?s Scientific Manuscript database

Salmonella ser. Enteritidis is a major public health concern worldwide. Loop-mediated isothermal amplification (LAMP) is a novel simple, easy-to-operate detection technology that amplifies DNA with high speed, efficiency, and specificity under isothermal conditions. The objective of this study was t...

Synthesis of K2SiF6:Mn4+ phosphor for LED lamp

NASA Astrophysics Data System (ADS)

Takarkhede, M. G.; Patil, R. R.; Moharil, S. V.; Joshi, C. P.; Talewar, Rupesh

2018-05-01

Now a days red emitting Mn4+ activated dialkali fluorosilicate phosphors have found applications in solid state lighting and displays. In this paper we describe development of K2SiF6 phosphor doped with Mn synthesized by simple method using Si metal powder with addition of oxidizing agent KMnO4. The photoluminescence spectra of K2SiF6:Mn show that emission is in the red region. In addition to this we studied LED spectra by coating the LED with phosphor mixed in different proportions with epoxy.

Polar and semipolar GaN/Al0.5Ga0.5N nanostructures for UV light emitters

NASA Astrophysics Data System (ADS)

Brault, J.; Rosales, D.; Damilano, B.; Leroux, M.; Courville, A.; Korytov, M.; Chenot, S.; Vennéguès, P.; Vinter, B.; De Mierry, P.; Kahouli, A.; Massies, J.; Bretagnon, T.; Gil, B.

2014-06-01

AlxGa1-xN-based ultra-violet (UV) light emitting diodes (LEDs) are seen as the best solution for the replacement of traditional mercury lamp technology. By adjusting the Al concentration, a large emission spectrum range from 360 nm (GaN) down to 200 nm (AlN) can be covered. Owing to the large density of defects typically present in AlxGa1-xN materials usually grown on sapphire substrates, LED efficiencies still need to be improved. Taking advantage of the 3D carrier confinement, quantum dots (QDs) are among the solutions currently under investigation to improve the performances of UV LEDs. The objectives of this work are to present and discuss the morphological and optical properties of GaN nanostructures grown by molecular beam epitaxy on the (0 0 0 1) and the (11-22) orientations of Al0.5Ga0.5N. In particular, the dependence of the morphological properties of the nanostructures on the growth conditions and the surface orientation will be presented. The optical characteristics as a function of the nanostructure design (size, shape and dimensionality) will also be shown and discussed. The electroluminescence characteristics of a first series of QD-based GaN/Al0.5Ga0.5N LEDs grown on the polar (0 0 0 1) plane will be investigated.

Max Tech and Beyond: High-Intensity Discharge Lamps

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

Scholand, Michael

High-intensity discharge (HID) lamps are most often found in industrial and commercial applications, and are the light source of choice in street and area lighting, and sports stadium illumination. HID lamps are produced in three types - mercury vapor (MV), high pressure sodium (HPS) and metal halide (MH). Of these, MV and MH are considered white-light sources (although the MV exhibits poor color rendering) and HPS produces a yellow-orange color light. A fourth lamp, low-pressure sodium (LPS), is not a HID lamp by definition, but it is used in similar applications and thus is often grouped with HID lamps. Withmore » the notable exception of MV which is comparatively inefficient and in decline in the US from both a sales and installed stock point of view; HPS, LPS and MH all have efficacies over 100 lumens per watt. The figure below presents the efficacy trends over time for commercially available HID lamps and LPS, starting with MV and LPS in 1930's followed by the development of HPS and MH in the 1960's. In HID lamps, light is generated by creating an electric arc between two electrodes in an arc tube. The particles in the arc are partially ionized, making them electrically conductive, and a light-emitting 'plasma' is created. This arc occurs within the arc tube, which for most HID lamps is enclosed within an evacuated outer bulb that thermally isolates and protects the hot arc tube from the surroundings. Unlike a fluorescent lamp that produces visible light through down-converting UV light with phosphors, the arc itself is the light source in an HID lamp, emitting visible radiation that is characteristic of the elements present in the plasma. Thus, the mixture of elements included in the arc tube is one critical factor determining the quality of the light emitted from the lamp, including its correlated color temperature (CCT) and color rendering index (CRI). Similar to fluorescent lamps, HID lamps require a ballast to start and maintain stable operating conditions, and this necessitates additional power beyond that used by the lamp itself. HID lamps offer important advantages compared to other lighting technologies, making them well suited for certain applications. HID lamps can be very efficient, have long operating lives, are relatively temperature-insensitive and produce a large quantity of light from a small package. For these reasons, HID lamps are often used when high levels of illumination are required over large areas and where operating and maintenance costs must be kept to a minimum. Furthermore, if the installation has a significant mounting height, high-power HID lamps can offer superior optical performance luminaires, reducing the number of lamps required to illuminate a given area. The indoor environments best suited to HID lamps are those with high ceilings, such as those commonly found in industrial spaces, warehouses, large retail spaces, sports halls and large public areas. Research into efficacy improvements for HID lighting technologies has generally followed market demand for these lamps, which is in decline for MV and LPS, has reached a plateau for HPS and is growing for MH. Several manufacturers interviewed for this study indicated that although solid-state lighting was now receiving the bulk of their company's R&D investment, there are still strong HID lamp research programs, which concentrate on MH technologies, with some limited amount of investment in HPS for specific niche applications (e.g., agricultural greenhouses). LPS and MV lamps are no longer being researched or improved in terms of efficacy or other performance attributes, although some consider MH HID lamps to be the next-generation MV lamp. Thus, the efficacy values of commercially available MV, LPS and HPS lamps are not expected to increase in the next 5 to 10 years. MH lamps, and more specifically, ceramic MH lamps are continuing to improve in efficacy as well as light quality, manufacturability and lamp life. Within an HID lamp, the light-producing plasma must be heated to sufficiently high temperatures to achieve high efficiencies, without melting the electrodes or altering the operating conditions of the lamp. The research in ceramic MH has focused on the arc tube, the electrodes and the plasma, resulting in an innovation announced by Philips Lighting in 2009 called the 'unsaturated lamp.' The unsaturated lamp addresses a problem experienced by standard ceramic MH lamps where a pool of liquid salt develops in the arc tube while the lamp is operating. This pool of liquid salt limits the light characteristics of the lamp such as the efficacy and color quality, and reduces lamp lifetime. By making modifications to the arc tube, the pressure and the operating temperature, the unsaturated ceramic MH lamp resolves this issue by keeping all the halide salts in the gaseous phase, even while the lamp is dimming (down to 50%).« less

[Tanning lamp radiation-induced photochemical retinal damage].

PubMed

Volkov, V V; Kharitonova, N N; Mal'tsev, D S

2014-01-01

On the basis of original clinical research a rare case of bilateral retinal damage due to tanning lamp radiation exposure is presented. Along with significant decrease of visual acuity and light sensitivity of central visual field as well as color vision impairment, bilateral macular dystrophy was found during an ophthalmoscopy and confirmed by optical coherent tomography and fluorescent angiography. Intensive retinoprotective, vascular, and antioxidant therapy was effective and led to functional improvement and stabilization of the pathologic process associated with photochemical retinal damage. A brief review of literature compares mechanisms of retinal damage by either short or long-wave near visible radiation.

Xenon lighting adjusted to plant requirements

NASA Technical Reports Server (NTRS)

Koefferlein, M.; Doehring, T.; Payer, Hans D.; Seidlitz, H. K.

1994-01-01

Xenon lamps are available as low and high power lamps with relatively high efficiency and a relatively long lifetime up to several thousand hours. Different construction types of short-arc and long-arc lamps permit a good adaptation to various applications in projection and illumination techniques without substantial changes of the spectral quality. Hence, the xenon lamp was the best choice for professional technical purposes where high power at simultaneously good spectral quality of the light was required. However, technical development does not stand still. Between the luminous efficacy of xenon lamps of 25-50 lm/W and the theoretical limit for 'white light' of 250 lm/W is still much room for improvement. The present development mainly favors other lamp types, like metal halide lamps and fluorescent lamps for commercial lighting purposes. The enclosed sections deal with some of the properties of xenon lamps relevant to plant illumination; particularly the spectral aspects, the temporal characteristics of the emission, and finally the economy of xenon lamps will be addressed. Due to radiation exceeding the natural global radiation in both the ultraviolet (UV) and the infrared (IR) regions, filter techniques have to be included into the discussion referring to the requirements of plant illumination. Most of the presented results were obtained by investigations in the GSF phytotron or in the closed Phytocell chambers of the University of Erlangen. As our experiences are restricted to area plant illumination rather than spot lights our discussion will concentrate on low pressure long-arc xenon lamps which are commonly used for such plant illuminations. As the spectral properties of short-arc lamps do not differ much from those of long-arc lamps most of our conclusions will be valid for high pressure xenon lamps too. These lamps often serve as light sources for small sun simulators and for monochromators which are used for action spectroscopy of plant responses.

Self-induced optogalvanic effect in a segmented hollow-cathode discharge

NASA Astrophysics Data System (ADS)

Steflekova, V.; Zhechev, D.

2018-03-01

Optogalvanic (OG) interaction is simulated and studied in a segmented hollow-cathode discharge (SHCD). HCD-lamps are used to induce an OG signal by their own emission or by that of another lamp. The efficiency of the OG of a Ne/Cu HCD lamp in the range 320-380 nm is estimated theoretically. An irregular galvanic peak arising near the inflection point in the i-V curve (∂V/∂i<0) is detected. Its origin is related to Penning ionization of the sputtered cathode material.

The effect of cap lamp lighting on postural control and stability

PubMed Central

Sammarco, John J.; Pollard, Jonisha P.; Porter, William L.; Dempsey, Patrick G.; Moore, Caitlin T.

2015-01-01

Researchers at the National Institute for Occupational Safety and Health (NIOSH) are conducting mine illumination research with the objective of improving miner safety. Slips, trips, and falls (STFs) are the second leading accident class (18.1%, n = 2,374) of nonfatal lost-time injuries at underground mines (MSHA, 2005–2009). Factors contributing to STFs include recognition of hazards as well as postural balance and age. Improved lighting may enable better hazard recognition and reduce the impact of postural balance and age. Previous research has shown that cap lamp technology that used light-emitting diodes (LEDs) has improved hazard detection. This study was an initial investigation to determine if cap lamp lighting significantly influences measures of static postural stability (displacement and velocity of center of pressure). Results of this investigation showed no significant differences in the balance measures of interest between cap lamps tested. However, balance was shown to significantly decline (p < 0.05) when tested in an underground coal mine compared to the laboratory testing condition. Relevance to industry: Underground coal mine workers wear cap lamps on their hard hats as their primary light source to illuminate nearby areas where their vision is directed. Proper illumination may improve miner safety by improving their STF hazard recognition and balance. PMID:26472917

Efficacy of Inactivation of Legionella pneumophila by Multiple-Wavelength UV LEDs

EPA Science Inventory

Background: Ultraviolet (UV) light has been successfully used for treating a broad suite of pathogens without the concomitant formation of carcinogenic disinfection by-products (DBPs). However, conventional mercury UV lamps have some practical limitations in water treatment appli...

Efficacy of Inactivation of Human Enteroviruses by Multiple-Wavelength UV LEDs

EPA Science Inventory

Ultraviolet (UV) light has been successfully used for treating a broad suite of pathogens without the concomitant formation of carcinogenic disinfection by-products (DBPs). However, conventional mercury UV lamps have some practical limitations in water treatment applications, suc...

A decline of LAMP- 2 predicts ursodeoxycholic acid response in primary biliary cirrhosis

PubMed Central

Wang, Lu; Guo, Guan-ya; Wang, Jing-bo; Zhou, Xin-min; Yang, Qiong; Han, Zhe-yi; Li, Qiang; Zhang, Jing-wen; Cai, Yun; Ren, Xiao-li; Zhou, Xia; Chen, Rui-rui; Shi, Yong-quan; Han, Ying; Fan, Dai-ming

2015-01-01

Biochemical response to ursodeoxycholic acid (UDCA) in patients with primary biliary cirrhosis (PBC) is variable. We have previously reported that augmented expression of lysosome-associated membrane protein 2 (LAMP-2) was correlated with the severity of PBC. This study aimed to determine whether serum LAMP-2 could serve as a predictor of biochemical response to UDCA. The efficiency of serum LAMP-2 to predict biochemical response was assessed after 1 year of UDCA treatment in PBC patients by a retrospective analysis. We found that the basal serum LAMP-2 level was increased in PBC, especially in patients with stage III-IV (p = 0.010) or TBIL > 1 mg/dL (p = 0.014). Baseline serum LAMP-2 was higher in non-responders than that in responders, but the difference was statistically insignificant. However, after UDCA treatment, serum LAMP-2 level decreased prominently in the first 3 months, which was more obvious in responders. Further studies showed that the 35% decline of LAMP-2 after treatment for 3 months could be stated as an indicator of UDCA response with the sensitivity of 62.9% and specificity of 75.0% by Paris criteria. Meanwhile the specificity and sensitivity were identified as 63.5% and 64.1% by Barcelona criteria. Together, a decline in LAMP-2 might help to predict the response to UDCA. PMID:25894308

The Novel Multiple Inner Primers-Loop-Mediated Isothermal Amplification (MIP-LAMP) for Rapid Detection and Differentiation of Listeria monocytogenes.

PubMed

Wang, Yi; Wang, Yan; Ma, Aijing; Li, Dongxun; Luo, Lijuan; Liu, Dongxin; Hu, Shoukui; Jin, Dong; Liu, Kai; Ye, Changyun

2015-12-03

Here, a novel model of loop-mediated isothermal amplification (LAMP), termed multiple inner primers-LAMP (MIP-LAMP), was devised and successfully applied to detect Listeria monocytogenes. A set of 10 specific MIP-LAMP primers, which recognized 14 different regions of target gene, was designed to target a sequence in the hlyA gene. The MIP-LAMP assay efficiently amplified the target element within 35 min at 63 °C and was evaluated for sensitivity and specificity. The templates were specially amplified in the presence of the genomic DNA from L. monocytogenes. The limit of detection (LoD) of MIP-LAMP assay was 62.5 fg/reaction using purified L. monocytogenes DNA. The LoD for DNA isolated from serial dilutions of L. monocytogenes cells in buffer and in milk corresponded to 2.4 CFU and 24 CFU, respectively. The amplified products were analyzed by real-time monitoring of changes in turbidity, and visualized by adding Loop Fluorescent Detection Reagent (FD), or as a ladder-like banding pattern on gel electrophoresis. A total of 48 pork samples were investigated for L. monocytogenes by the novel MIP-LAMP method, and the diagnostic accuracy was shown to be 100% when compared to the culture-biotechnical method. In conclusion, the MIP-LAMP methodology was demonstrated to be a reliable, sensitive and specific tool for rapid detection of L. monocytogenes strains.

Synthesis and photoluminescence properties of a cyan-emitting phosphor Ca3(PO4)2:Eu2+ for white light-emitting diodes

NASA Astrophysics Data System (ADS)

Zhou, Wenli; Han, Jin; Zhang, Xuejie; Qiu, Zhongxian; Xie, Qingji; Liang, Hongbin; Lian, Shixun; Wang, Jing

2015-01-01

In this paper, a cyan-emitting phosphor Ca3(PO4)2:Eu2+ (TCP:Eu2+) was synthesized and evaluated as a candidate for white light emitting diodes (WLEDs). This phosphor shows strong and broad absorption in 250-450 nm region, but the emission spectrum is prominent at around 480 nm. The emission intensity of the TCP:Eu2+ was found to be 60% and 82% of that of the commercial BaMgAl10O17:Eu2+ (BAM) under excitation at 340 nm and 370 nm, respectively. Upon excitation at 370 nm, the absolute internal and external quantum efficiencies of the Ca3(PO4)2:1.5%Eu2+ are 60% and 42%, respectively. Moreover, a white LED lamp was fabricated by coating TCP:Eu2+ with a blue-emitting BAM and a red-emitting CaAlSiN3:Eu2+ on a near-ultraviolet (375 nm) LED chip, driven by a 350 mA forward bias current, and it produces an intense white light with a color rendering index of 75.

Development of highly durable deep-ultraviolet AlGaN-based LED multichip array with hemispherical encapsulated structures using a selected resin through a detailed feasibility study

NASA Astrophysics Data System (ADS)

Nagai, Shoko; Yamada, Kiho; Hirano, Akira; Ippommatsu, Masamichi; Ito, Masahiro; Morishima, Naoki; Aosaki, Ko; Honda, Yoshio; Amano, Hiroshi; Akasaki, Isamu

2016-08-01

To replace mercury lamps with AlGaN-based deep-ultraviolet (DUV) LEDs, a simple and low-cost package with increased light extraction efficiency (LEE) is indispensable. Therefore, resin encapsulation is considered to be a key technology. However, the photochemical reactions induced by DUV light cause serious problems, and conventional resins cannot be used. In the former part of this study, a comparison of a silicone resin and fluorine polymers was carried out in terms of their suitability for encapsulation, and we concluded that only one of the fluorine polymers can be used for encapsulation. In the latter part, the endurance of encapsulation using the selected fluorine polymer was investigated, and we confirmed that the selected fluorine polymer can guarantee a lifetime of over 6,000 h at a wavelength of 265 nm. Furthermore, a 3 × 4 array module of encapsulated dies on a simple AlN submount was fabricated, demonstrating the possibility of W/cm2-class lighting.

Efficient 7-J flashlamp-pumped dye laser at 500-nm wavelength

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

Everett, P.N.; Aldag, H.R.; Ehrlich, J.J.

1986-07-01

An existing transverse flow flashlamp-pumped dye laser capable of operation at 500 pps for extended periods of time has been modified and optimized for operation at 502 nm using coumarin 504. Energies of over 7 J/ pulse and efficiencies of over 1% have been demonstrated in single-shot operation. This has been achieved by using a spectral transfer dye in the flashlamp coolant to increase the useful output of the flashlamps. Flashlamps were tested at up to 400-J input per lamp for extended periods to develop lamp life data.

Loop-mediated isothermal amplification (LAMP): a versatile technique for detection of micro-organisms.

PubMed

Wong, Y-P; Othman, S; Lau, Y-L; Radu, S; Chee, H-Y

2018-03-01

Loop-mediated isothermal amplification (LAMP) amplifies DNA with high specificity, efficiency and rapidity under isothermal conditions by using a DNA polymerase with high displacement strand activity and a set of specifically designed primers to amplify targeted DNA strands. Following its first discovery by Notomi et al. ( Nucleic Acids Res 28: E63), LAMP was further developed over the years which involved the combination of this technique with other molecular approaches, such as reverse transcription and multiplex amplification for the detection of infectious diseases caused by micro-organisms in humans, livestock and plants. In this review, available types of LAMP techniques will be discussed together with their applications in detection of various micro-organisms. Up to date, there are varieties of LAMP detection methods available including colorimetric and fluorescent detection, real-time monitoring using turbidity metre and detection using lateral flow device which will also be highlighted in this review. Apart from that, commercialization of LAMP technique had also been reported such as lyophilized form of LAMP reagents kit and LAMP primer sets for detection of pathogenic micro-organisms. On top of that, advantages and limitations of this molecular detection method are also described together with its future potential as a diagnostic method for infectious disease. © 2017 The Society for Applied Microbiology.

Importance of 'blue' photon levels for lettuce seedlings grown under red-light-emitting diodes

NASA Technical Reports Server (NTRS)

Hoenecke, M. E.; Bula, R. J.; Tibbitts, T. W.

1992-01-01

Light-emitting diodes (LEDs) with high-intensity output are being studied as a photosynthetic light source for plants. High-output LEDs have peak emission at approximately 660 nm concentrated in a waveband of +/- 30 nm. Lettuce (Lactuca sativa Grand Rapids') seedlings developed extended hypocotyls and elongated cotyledons when grown under these LEDs as a sole source of irradiance. This extension and elongation was prevented when the red LED radiation was supplemented with more than 15 micromoles m-2 s-1 of 400- to 500-nm photons from blue fluorescent lamps. Blue radiation effects were independent of the photon level of the red radiation.

Fucosylation of LAMP-1 and LAMP-2 by FUT1 correlates with lysosomal positioning and autophagic flux of breast cancer cells.

PubMed

Tan, Keng-Poo; Ho, Ming-Yi; Cho, Huan-Chieh; Yu, John; Hung, Jung-Tung; Yu, Alice Lin-Tsing

2016-08-25

Alpha1,2-fucosyltransferases, FUT1 and FUT2, which transfer fucoses onto the terminal galactose of N-acetyl-lactosamine via α1,2-linkage have been shown to be highly expressed in various types of cancers. A few studies have shown the involvement of FUT1 substrates in tumor cell proliferation and migration. Lysosome-associated membrane protein 1, LAMP-1, has been reported to carry alpha1,2-fucosylated Lewis Y (LeY) antigens in breast cancer cells, however, the biological functions of LeY on LAMP-1 remain largely unknown. Whether or not its family member, LAMP-2, displays similar modifications and functions as LAMP-1 has not yet been addressed. In this study, we have presented evidence supporting that both LAMP-1 and 2 are substrates for FUT1, but not FUT2. We have also demonstrated the presence of H2 and LeY antigens on LAMP-1 by a targeted nanoLC-MS(3) and the decreased levels of fucosylation on LAMP-2 by MALDI-TOF analysis upon FUT1 knockdown. In addition, we found that the expression of LeY was substantial in less invasive ER+/PR+/HER- breast cancer cells (MCF-7 and T47D) but negligible in highly invasive triple-negative MDA-MB-231 cells, of which LeY levels were correlated with the levels of LeY carried by LAMP-1 and 2. Intriguingly, we also observed a striking change in the subcellular localization of lysosomes upon FUT1 knockdown from peripheral distribution of LAMP-1 and 2 to a preferential perinuclear accumulation. Besides that, knockdown of FUT1 led to an increased rate of autophagic flux along with diminished activity of mammalian target of rapamycin complex 1 (mTORC1) and enhanced autophagosome-lysosome fusion. This may be associated with the predominantly perinuclear distribution of lysosomes mediated by FUT1 knockdown as lysosomal positioning has been reported to regulate mTOR activity and autophagy. Taken together, our results suggest that downregulation of FUT1, which leads to the perinuclear localization of LAMP-1 and 2, is correlated with increased rate of autophagic flux by decreasing mTOR signaling and increasing autolysosome formation.

Fucosylation of LAMP-1 and LAMP-2 by FUT1 correlates with lysosomal positioning and autophagic flux of breast cancer cells

PubMed Central

Tan, Keng-Poo; Ho, Ming-Yi; Cho, Huan-Chieh; Yu, John; Hung, Jung-Tung; Yu, Alice Lin-Tsing

2016-01-01

Alpha1,2-fucosyltransferases, FUT1 and FUT2, which transfer fucoses onto the terminal galactose of N-acetyl-lactosamine via α1,2-linkage have been shown to be highly expressed in various types of cancers. A few studies have shown the involvement of FUT1 substrates in tumor cell proliferation and migration. Lysosome-associated membrane protein 1, LAMP-1, has been reported to carry alpha1,2-fucosylated Lewis Y (LeY) antigens in breast cancer cells, however, the biological functions of LeY on LAMP-1 remain largely unknown. Whether or not its family member, LAMP-2, displays similar modifications and functions as LAMP-1 has not yet been addressed. In this study, we have presented evidence supporting that both LAMP-1 and 2 are substrates for FUT1, but not FUT2. We have also demonstrated the presence of H2 and LeY antigens on LAMP-1 by a targeted nanoLC-MS3 and the decreased levels of fucosylation on LAMP-2 by MALDI-TOF analysis upon FUT1 knockdown. In addition, we found that the expression of LeY was substantial in less invasive ER+/PR+/HER− breast cancer cells (MCF-7 and T47D) but negligible in highly invasive triple-negative MDA-MB-231 cells, of which LeY levels were correlated with the levels of LeY carried by LAMP-1 and 2. Intriguingly, we also observed a striking change in the subcellular localization of lysosomes upon FUT1 knockdown from peripheral distribution of LAMP-1 and 2 to a preferential perinuclear accumulation. Besides that, knockdown of FUT1 led to an increased rate of autophagic flux along with diminished activity of mammalian target of rapamycin complex 1 (mTORC1) and enhanced autophagosome–lysosome fusion. This may be associated with the predominantly perinuclear distribution of lysosomes mediated by FUT1 knockdown as lysosomal positioning has been reported to regulate mTOR activity and autophagy. Taken together, our results suggest that downregulation of FUT1, which leads to the perinuclear localization of LAMP-1 and 2, is correlated with increased rate of autophagic flux by decreasing mTOR signaling and increasing autolysosome formation. PMID:27560716

Sole-Source Lighting for Controlled-Environment Agriculture

NASA Technical Reports Server (NTRS)

Mitchell.Cary; Stutte, Gary W.

2015-01-01

Since plants on Earth evolved under broad-spectrum solar radiation, anytime they are grown exclusively under electric lighting that does not contain all wavelengths in similar proportion to those in sunlight, plant appearance and size could be uniquely different. Nevertheless, plants have been grown for decades under fluorescent (FL) (1) + incandescent (IN) (2) lamps as a sole source of lighting (SSL), and researchers have become comfortable that, in certain proportions of FL + IN for a given species, plants can appear "normal" relative to their growth outdoors. The problem with using such traditional SSLs for commercial production typically is short lamp lifespans and not obtaining enough photosynthetically active radiation (PAR, 400-700 nm) when desired. These limitations led to supplementation of FL + IN lamp outputs with longer-lived, high-intensity discharge (HID) lamps in growth chambers (3). As researchers became comfortable that mixes of orange-biased high-pressure sodium (HPS) and blue-biased metal halide (MH) HIDs together also could give normal plant growth at higher intensities, growth chambers and phytotrons subsequently were equipped mainly with HID lamps, with their intense thermal output filtered out by ventilated light caps or thermal-controlled water barriers. For the most part, IN and HID lamps have found a home in commercial protected horticulture, usually for night-break photoperiod lighting (IN) or for seasonal supplemental lighting (mostly HPS) in greenhouses. However, lack of economically viable options for SSL have held back aspects of year-round indoor agriculture from taking off commercially.

Comparing colour discrimination and proofreading performance under compact fluorescent and halogen lamp lighting.

PubMed

Mayr, Susanne; Köpper, Maja; Buchner, Axel

2013-01-01

Legislation in many countries has banned inefficient household lighting. Consequently, classic incandescent lamps have to be replaced by more efficient alternatives such as halogen and compact fluorescent lamps (CFL). Alternatives differ in their spectral power distributions, implying colour-rendering differences. Participants performed a colour discrimination task - the Farnsworth-Munsell 100 Hue Test--and a proofreading task under CFL or halogen lighting of comparable correlated colour temperatures at low (70 lx) or high (800 lx) illuminance. Illuminance positively affected colour discrimination and proofreading performance, whereas the light source was only relevant for colour discrimination. Discrimination was impaired with CFL lighting. There were no differences between light sources in terms of self-reported physical discomfort and mood state, but the majority of the participants correctly judged halogen lighting to be more appropriate for discriminating colours. The findings hint at the colour-rendering deficiencies associated with energy-efficient CFLs. In order to compare performance under energy-efficient alternatives of classic incandescent lighting, colour discrimination and proofreading performance was compared under CFL and halogen lighting. Colour discrimination was impaired under CFLs, which hints at the practical drawbacks associated with the reduced colour-rendering properties of energy-efficient CFLs.

Applying visual attention theory to transportation safety research and design: evaluation of alternative automobile rear lighting systems.

PubMed

McIntyre, Scott E; Gugerty, Leo

2014-06-01

This field experiment takes a novel approach in applying methodologies and theories of visual search to the subject of conspicuity in automobile rear lighting. Traditional rear lighting research has not used the visual search paradigm in experimental design. It is our claim that the visual search design uniquely uncovers visual attention processes operating when drivers search the visual field that current designs fail to capture. This experiment is a validation and extension of previous simulator research on this same topic and demonstrates that detection of red automobile brake lamps will be improved if tail lamps are another color (in this test, amber) rather than the currently mandated red. Results indicate that when drivers miss brake lamp onset in low ambient light, RT and error are reduced in detecting the presence and absence of red brake lamps with multiple lead vehicles when tail lamps are not red compared to current rear lighting which mandates red tail lamps. This performance improvement is attributed to efficient visual processing that automatically segregates tail (amber) and brake (red) lamp colors into distractors and targets respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Digital Microfluidics Platform for Loop-Mediated Isothermal Amplification Detection

PubMed Central

Veigas, Bruno; Águas, Hugo; Fortunato, Elvira; Martins, Rodrigo; Baptista, Pedro Viana; Igreja, Rui

2017-01-01

Digital microfluidics (DMF) arises as the next step in the fast-evolving field of operation platforms for molecular diagnostics. Moreover, isothermal schemes, such as loop-mediated isothermal amplification (LAMP), allow for further simplification of amplification protocols. Integrating DMF with LAMP will be at the core of a new generation of detection devices for effective molecular diagnostics at point-of-care (POC), providing simple, fast, and automated nucleic acid amplification with exceptional integration capabilities. Here, we demonstrate for the first time the role of coupling DMF and LAMP, in a dedicated device that allows straightforward mixing of LAMP reagents and target DNA, as well as optimum temperature control (reaction droplets undergo a temperature variation of just 0.3 °C, for 65 °C at the bottom plate). This device is produced using low-temperature and low-cost production processes, adaptable to disposable and flexible substrates. DMF-LAMP is performed with enhanced sensitivity without compromising reaction efficacy or losing reliability and efficiency, by LAMP-amplifying 0.5 ng/µL of target DNA in just 45 min. Moreover, on-chip LAMP was performed in 1.5 µL, a considerably lower volume than standard bench-top reactions. PMID:29144379

Investigating and Optimizing Carrier Transport, Carrier Distribution, and Efficiency Droop in GaN-based Light-emitting Diodes

NASA Astrophysics Data System (ADS)

Zhu, Di

2011-12-01

The recent tremendous boost in the number and diversity of applications for light-emitting diodes (LEDs) indicates the emergence of the next-generation lighting and illumination technology. The rapidly improving LED technology is becoming increasingly viable especially for high-power applications. However, the greatest roadblock before finally breaching the main defensive position of conventional fluorescent and incandescent lamps still remains: GaN-based LEDs encounter a significant decrease in efficiency as the drive current increases, and this phenomenon is known as the efficiency droop. This dissertation focuses on uncovering the physical cause of efficiency droop in GaN-based LEDs and looks for solutions to it. GaN-based multiple-quantum-well (MQW) LEDs usually have abnormally high diode-ideality factors. Investigating the origin of the high diode-ideality factors could help to better understand the carrier transport in the LED MQW active region. We investigate the ideality factors of GaInN LEDs with different numbers of doped quantum barriers (QBs). Consistent with the theory, a decrease of the ideality factor as well as a reduction in forward voltage is found with increasing number of doped QBs. Experimental and simulation results indicate that the band profiles of QBs in the active region have a significant impact on the carrier transport mechanism, and the unipolar heterojunctions inside the active region play an important role in determining the diode-ideality factor. This dissertation will discuss several mechanisms leading to electron leakage which could be responsible for the efficiency droop. We show that the inefficient electron capture, the electron-attracting properties of polarized EBL, the inherent asymmetry in electron and hole transport and the inefficient EBL p-doping at high Al contents severely limit the ability to confine electrons to the MQWs. We demonstrate GaInN LEDs employing tailored Si doping in the QBs with strongly enhanced high-current efficiency and reduced efficiency droop. Compared with 4-QB-doped LEDs, 1-QB-doped LEDs show a 37.5% increase in light-output power at high currents. Consistent with the measurements, simulation shows a shift of radiative recombination among the MQWs and a reduced electron leakage current into the p-type GaN when fewer QBs are doped. The results can be attributed to a more symmetric carrier transport and uniform carrier distribution which help to reduce electron leakage and thus reduce the efficiency droop. In this dissertation, artificial evolution is introduced to the LED optimization process which combines a genetic algorithm (GA) and device-simulation software. We show that this approach is capable of generating novel concepts in designing and optimizing LED devices. Application of the GA to the QB-doping in the MQWs yields optimized structures which is consistent with the tailored QB doping experiments. Application of the GA to the EBL region suggests a novel structure with an inverted sheet charge at the spacer-EBL interface. The resulting repulsion of electrons can significantly reduce electron leakage and enhance the efficiency. Finally, dual-wavelength LEDs, which have two types of quantum wells (QWs) emitting at two different wavelengths, are experimentally characterized and compared with numerical simulations. These dual-wavelength LEDs allow us to determine which QW emits most of the light. An experimental observation and a quantitative analysis of the radiative recombination shift within the MQW active region are obtained. In addition, an injection-current dependence of the radiative recombination shift is predicted by numerical simulations and indeed observed in dual-wavelength LEDs. This injection-current dependence of the radiative recombination distribution can be explained very well by incorporating quantum-mechanical tunneling of carriers into and through the QBs into to the classical drift-diffusion model. In summary, using the LEDs with tailored QB doping and dual-wavelength LEDs, we investigate the origin of the high diode-ideality factor of LEDs and gain insight on the control of carrier transport, carrier distribution, and radiative recombination in the LED MQW active region. Our results provide solid evidence on the effectiveness of the GA in the LED device optimization process. In addition, the innovative EBL structure optimized by the GA sheds light on further paths for the optimization of LED design. Our results are the starting point of applying artificial evolution to practical semiconductor devices, opening new perspectives for complex semiconductor device optimization and enabling breakthroughs in high-performance LED design.

LED mini-lidar as minimum setup

NASA Astrophysics Data System (ADS)

Shiina, Tatsuo

2014-10-01

The LED mini-lidar has been designed and demonstrated as the near range atmosphere monitoring, dust and gas detections. The LED lamp is used as a lidar light source. It is not a special one, and just used as a small status indicator or a spot luminaire. For the atmospheric monitoring in the near range of a few hundreds meters, the energy of 1nJ (=100mW/10ns) is enough for lidar observation in the nighttime. The LED lamp is excited at the high repetition frequency of < 1MHz. The signal-to-noise ratio can be increased by this high frequency even if the receiving photons are a little at each pulse. It is adequate because the spatiotemporal scale of the low-altitude atmosphere is small of a ten seconds and a few tens meters. To pursue such quick motion of the atmosphere and dust, the high-speed photon counter has been developed. It can act with BIN width of 4ns (Spatial resolution 0.6m) at the repetition frequency of <500kHz. The LED mini-lidar has been demonstrated to monitor the actual atmosphere of the observation range of <500m in the nighttime and <100m in the daytime with the receiving lens of 200mmφ. The interest approach is tired to distinguish the dust characteristics by using the counting rate of dust echoes. It is effective in the case that the dust material is given. And for trial, the LED mini-Raman-lidar is developed to monitor certain gas detection in near distance, too.

New design for a microwave discharge lamp.

PubMed

Glangetas, A

1980-03-01

A simple discharge lamp with a microwave cavity fitting inside provides an intense source of VUV resonance radiation for photochemical work inside a vacuum chamber. Good coupling and minimum reabsorption result in better efficiency ( greater, similar1%) and more intense output power (up to 2.5x10(16) quanta s(-1)) than have been achieved previously.

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

Alstone, Peter; Mills, Evan; Jacobson, Arne

The greenhouse gas (GHG) emissions from fuel-based lighting are substantial given the paltry levels of lighting service provided to users, leading to a great opportunity for GHG mitigation byencouraging the switch from fuel-based to rechargeable LED lighting. However, as with most new energy technology, switching to efficient lighting requires an up-front investment of energy(and GHGs) embedded in the manufacture of replacement components. We studied a population of off-grid lighting users in 2008-2009 in Kenya who were given the opportunity to adopt LEDlighting. Based on their use patterns with the LED lights and the levels of kerosene offset we observed, wemore » found that the embodied energy of the LED lamp was"paid for" in only one month for grid charged products and two months for solar charged products. Furthermore, the energyreturn-on investment-ratio (energy produced or offset over the product's service life divided by energy embedded) for off-grid LED lighting ranges from 12 to 24, which is on par with on-gridsolar and large-scale wind energy. We also found that the energy embodied in the manufacture of a typical hurricane lantern is about one-half to one-sixth of that embodied in the particular LEDlights that we evaluated, indicating that the energy payback time would be moderately faster if LEDs ultimately displace the production of kerosene lanterns. As LED products improve, weanticipate longer service lives and more successful displacement of kerosene lighting, both of which will speed the already rapid recovery of embodied energy in these products. Our studyprovides a detailed appendix with embodied energy values for a variety of components used to construct off-grid LED lighting, which can be used to analyze other products.« less

LED Curing Lights and Temperature Changes in Different Tooth Sites

PubMed Central

Armellin, E.; Bovesecchi, G.; Coppa, P.; Pasquantonio, G.; Cerroni, L.

2016-01-01

Objectives. The aim of this in vitro study was to assess thermal changes on tooth tissues during light exposure using two different LED curing units. The hypothesis was that no temperature increase could be detected within the dental pulp during polymerization irrespective of the use of a composite resin or a light-curing unit. Methods. Caries-free human first molars were selected, pulp residues were removed after root resection, and four calibrated type-J thermocouples were positioned. Two LED lamps were tested; temperature measurements were made on intact teeth and on the same tooth during curing of composite restorations. The data was analyzed by one-way analysis of variance (ANOVA), Wilcoxon test, Kruskal-Wallis test, and Pearson's χ 2. After ANOVA, the Bonferroni multiple comparison test was performed. Results. Polymerization data analysis showed that in the pulp chamber temperature increase was higher than that without resin. Starlight PRO, in the same condition of Valo lamp, showed a lower temperature increase in pre- and intrapolymerization. A control group (without composite resin) was evaluated. Significance. Temperature increase during resin curing is a function of the rate of polymerization, due to the exothermic polymerization reaction, the energy from the light unit, and time of exposure. PMID:27195282

LED Curing Lights and Temperature Changes in Different Tooth Sites.

PubMed

Armellin, E; Bovesecchi, G; Coppa, P; Pasquantonio, G; Cerroni, L

2016-01-01

Objectives. The aim of this in vitro study was to assess thermal changes on tooth tissues during light exposure using two different LED curing units. The hypothesis was that no temperature increase could be detected within the dental pulp during polymerization irrespective of the use of a composite resin or a light-curing unit. Methods. Caries-free human first molars were selected, pulp residues were removed after root resection, and four calibrated type-J thermocouples were positioned. Two LED lamps were tested; temperature measurements were made on intact teeth and on the same tooth during curing of composite restorations. The data was analyzed by one-way analysis of variance (ANOVA), Wilcoxon test, Kruskal-Wallis test, and Pearson's χ (2). After ANOVA, the Bonferroni multiple comparison test was performed. Results. Polymerization data analysis showed that in the pulp chamber temperature increase was higher than that without resin. Starlight PRO, in the same condition of Valo lamp, showed a lower temperature increase in pre- and intrapolymerization. A control group (without composite resin) was evaluated. Significance. Temperature increase during resin curing is a function of the rate of polymerization, due to the exothermic polymerization reaction, the energy from the light unit, and time of exposure.

Efficacy of Inactivation of Human Enteroviruses by Multiple-Wavelength UV LEDs - abstract

EPA Science Inventory

Background: Ultraviolet (UV) light has been successfully used for treating a broad suite of pathogens without the concomitant formation of carcinogenic disinfection by-products (DBPs). However, conventional mercury UV lamps have some practical limitations in water treatment appli...

Tuning optical radiation for visual and nonvisual impact

NASA Astrophysics Data System (ADS)

Royer, Michael P.

2011-12-01

Spectral tuning---the allocation of radiant energy emitted by a lamp---is a fundamental element of illuminating engineering. Proper placement of optical radiation allows for reduced energy consumption, increased brightness perception, and improved color rendition. It can also result in lamps that have a greater impact on nonvisual human functions such as circadian rhythms, sleep, mood, and cognition. For an architectural lighting system, careful consideration must be given to all of these areas; recent advancements in understanding nonvisual photoreception must be balanced with the traditional emphasis on visual quality and energy efficiency. The three research projects described herein investigated spectral tuning by examining the effects of optical radiation or seeking ideal spectral power distributions. In all three cases, emphasis was placed on developing an architectural lighting system based on red, green, and blue (RGB) light emitting diodes (LEDs) that is capable of providing maximum stimulation to nonvisual systems while maintaining visual quality standards. In particular, the elderly were considered as a target population because they have an increased risk of developing disorders linked to illumination deficits. The three endeavors can be summarized as follows: Light Therapy for Seniors in Long-term Care AIM: To examine the effect of optical radiation on circadian rhythms, sleep, mood, and cognition for frail elderly in a long-term care environment. METHODOLOGY: A double-blind, placebo-controlled clinical trial of light therapy was conducted using circadian-effective short-wavelength (blue) optical radiation to treat a sample of residents recruited for participation without bias for existing medical diagnoses. KEY FINDINGS: Light therapy treatment improved cognitive functioning compared to placebo but no changes were detected in nighttime sleep statistics, reports of daytime sleepiness, circadian rhythms, or depression inventory parameters. Perceived Brightness of Trichromatic Light Sources AIM: To examine the effect of tuning optical radiation on brightness perception for younger (18-25 years of age) and older (50 years of age or older) observers. METHODOLOGY: Participants made forced-choice evaluations of the brightness of a full factorial of stimulus pairs selected from two groups of four metameric stimuli. The large-field stimuli were created by systematically varying either the red or the blue primary of an RGB LED mixture. KEY FINDINGS: Light stimuli of equal illuminance and chromaticity do not appear equally bright to either younger or older subjects. The rank-order of brightness is not predicted by any current model of human vision or theory of brightness perception including Scotopic to Photopic or Cirtopic to Photopic ratio theory, prime color theory, correlated color temperature, photometry, color quality metrics, linear brightness models, or color appearance models. Age may affect brightness perception when short-wavelength primaries are used, especially those with a peak wavelength shorter than 450 nm. Optimizing RGB LED Mixtures AIM: To investigate potential tradeoffs between luminous efficacy, nonvisual efficacy, and color quality of RGB LED mixtures when the peak wavelength and full with half maximum of the primaries are varied. To identify mixtures suitable for architectural lighting which provide increased circadian stimulation. METHODOLOGY: Software to calculate the properties of RGB LED mixtures matching the chromaticity of blackbody radiation was developed using Microsoft Excel and Visual Basic. Excel Solver was used to perform a series of optimization routines, identifying high-performing mixtures that were then compared to traditional lamps. KEY FINDINGS: Trichromatic mixtures suitable for architectural interiors can outperform traditional lamps when luminous efficacy, nonvisual efficacy, and color quality are considered simultaneously. However, misplacement of radiant energy can result in poor performing trichromatic systems. When radiant energy is manipulated, tradeoffs may occur between luminous efficacy, nonvisual efficacy, and color quality.

Evaluation of Different PCR-Based Assays and LAMP Method for Rapid Detection of Phytophthora infestans by Targeting the Ypt1 Gene

PubMed Central

Khan, Mehran; Li, Benjin; Jiang, Yue; Weng, Qiyong; Chen, Qinghe

2017-01-01

Late blight, caused by the oomycete Phytophthora infestans, is one of the most devastating diseases affecting potato and tomato worldwide. Early diagnosis of the P. infestans pathogen causing late blight should be the top priority for addressing disease epidemics and management. In this study, we performed a loop-mediated isothermal amplification (LAMP) assay, conventional polymerase chain reaction (PCR), nested PCR, and real-time PCR to verify and compare the sensitivity and specificity of the reaction based on the Ypt1 (Ras-related protein) gene of P. infestans. In comparison with the PCR-based assays, the LAMP technique led to higher specificity and sensitivity, using uncomplicated equipment with an equivalent time frame. All 43 P. infestans isolates, yielded positive detection results using LAMP assay showing no cross reaction with other Phytophthora spp., oomycetes or fungal pathogens. The LAMP assay yielded the lowest detectable DNA concentration (1.28 × 10-4 ng μL-1), being 10 times more sensitive than nested PCR (1.28 × 10-3 ng μL-1), 100 times more sensitive than real-time PCR (1.28 × 10-2 ng μL-1) and 103 times more sensitive than the conventional PCR assay (1.28 × 10-1 ng μL-1). In the field experiment, the LAMP assay outperformed the other tests by amplifying only diseased tissues (leaf and stem), and showing no positive reaction in healthy tissues. Overall, the LAMP assay developed in this study provides a specific, sensitive, simple, and effective visual method for detection of the P. infestans pathogen, and is therefore suitable for application in early prediction of the disease to reduce the risk of epidemics. PMID:29051751

Meat Species Identification using Loop-mediated Isothermal Amplification Assay Targeting Species-specific Mitochondrial DNA.

PubMed

Cho, Ae-Ri; Dong, Hee-Jin; Cho, Seongbeom

2014-01-01

Meat source fraud and adulteration scandals have led to consumer demands for accurate meat identification methods. Nucleotide amplification assays have been proposed as an alternative method to protein-based assays for meat identification. In this study, we designed Loop-mediated isothermal amplification (LAMP) assays targeting species-specific mitochondrial DNA to identify and discriminate eight meat species; cattle, pig, horse, goat, sheep, chicken, duck, and turkey. The LAMP primer sets were designed and the target genes were discriminated according to their unique annealing temperature generated by annealing curve analysis. Their unique annealing temperatures were found to be 85.56±0.07℃ for cattle, 84.96±0.08℃ for pig, and 85.99±0.05℃ for horse in the BSE-LAMP set (Bos taurus, Sus scrofa domesticus and Equus caballus); 84.91±0.11℃ for goat and 83.90±0.11℃ for sheep in the CO-LAMP set (Capra hircus and Ovis aries); and 86.31±0.23℃ for chicken, 88.66±0.12℃ for duck, and 84.49±0.08℃ for turkey in the GAM-LAMP set (Gallus gallus, Anas platyrhynchos and Meleagris gallopavo). No cross-reactivity was observed in each set. The limits of detection (LODs) of the LAMP assays in raw and cooked meat were determined from 10 pg/μL to 100 fg/μL levels, and LODs in raw and cooked meat admixtures were determined from 0.01% to 0.0001% levels. The assays were performed within 30 min and showed greater sensitivity than that of the PCR assays. These novel LAMP assays provide a simple, rapid, accurate, and sensitive technology for discrimination of eight meat species.

Evaluation of Different PCR-Based Assays and LAMP Method for Rapid Detection of Phytophthora infestans by Targeting the Ypt1 Gene.

PubMed

Khan, Mehran; Li, Benjin; Jiang, Yue; Weng, Qiyong; Chen, Qinghe

2017-01-01

Late blight, caused by the oomycete Phytophthora infestans , is one of the most devastating diseases affecting potato and tomato worldwide. Early diagnosis of the P. infestans pathogen causing late blight should be the top priority for addressing disease epidemics and management. In this study, we performed a loop-mediated isothermal amplification (LAMP) assay, conventional polymerase chain reaction (PCR), nested PCR, and real-time PCR to verify and compare the sensitivity and specificity of the reaction based on the Ypt1 (Ras-related protein) gene of P. infestans. In comparison with the PCR-based assays, the LAMP technique led to higher specificity and sensitivity, using uncomplicated equipment with an equivalent time frame. All 43 P. infestans isolates, yielded positive detection results using LAMP assay showing no cross reaction with other Phytophthora spp., oomycetes or fungal pathogens. The LAMP assay yielded the lowest detectable DNA concentration (1.28 × 10 -4 ng μL -1 ), being 10 times more sensitive than nested PCR (1.28 × 10 -3 ng μL -1 ), 100 times more sensitive than real-time PCR (1.28 × 10 -2 ng μL -1 ) and 10 3 times more sensitive than the conventional PCR assay (1.28 × 10 -1 ng μL -1 ). In the field experiment, the LAMP assay outperformed the other tests by amplifying only diseased tissues (leaf and stem), and showing no positive reaction in healthy tissues. Overall, the LAMP assay developed in this study provides a specific, sensitive, simple, and effective visual method for detection of the P. infestans pathogen, and is therefore suitable for application in early prediction of the disease to reduce the risk of epidemics.

Comments on: Accuracy of Raman Lidar Water Vapor Calibration and its Applicability to Long-Term Measurements

NASA Technical Reports Server (NTRS)

Whiteman, David N.; Venable, Demetrius; Landulfo, Eduardo

2012-01-01

In a recent publication, LeBlanc and McDermid proposed a hybrid calibration technique for Raman water vapor lidar involving a tungsten lamp and radiosondes. Measurements made with the lidar telescope viewing the calibration lamp were used to stabilize the lidar calibration determined by comparison with radiosonde. The technique provided a significantly more stable calibration constant than radiosondes used alone. The technique involves the use of a calibration lamp in a fixed position in front of the lidar receiver aperture. We examine this configuration and find that such a configuration likely does not properly sample the full lidar system optical efficiency. While the technique is a useful addition to the use of radiosondes alone for lidar calibration, it is important to understand the scenarios under which it will not provide an accurate quantification of system optical efficiency changes. We offer examples of these scenarios.

The synergetic effect of UV rays on the decomposition of xylene in dielectric barrier discharge plasma and photocatalyst process

NASA Astrophysics Data System (ADS)

Li, Wenjuan; Gu, Zhenyu; Teng, Fuhua; Lu, Jianhai; Dong, Shibi; Miao, Xiaoping; Wu, Zhongbiao

2018-06-01

The degradation of xylene in the dielectric barrier discharge plasma and photocatalyst process was studied, focusing on the synergetic effect of UV rays from plasma process and external UV lamps on the decomposition of xylene. The results showed that xylene could be decomposed by the discharge process in plasma system, whereas the UV rays from plasma process was very weak. After adding TiO2, the removal efficiency of xylene and energy yield in plasma process were enhanced since energetic particles activated the catalysis of TiO2. The removal efficiency of xylene and energy field in plasma and photocatalyst process combined with external UV lamps were further enhanced attributed to the degradation effect of plasma, the catalysis of TiO2 activated by plasma, the photolysis of UV rays and the photocatalysis of photocatalyst. The synergetic effect of UV rays from external UV lamps was obvious.

The translucency of dental composites investigated by UV-VIS spectroscopy

NASA Astrophysics Data System (ADS)

Dumitrescu, L. Silaghi; Pastrav, O.; Prejmerean, C.; Prodan, D.; Boboia, S.; Codruta, S.; Moldovan, M.

2013-11-01

Translucency is the property of a material to partially transmit and diffuse incident light, and can be described as a partial opacity or a state between complete opacity and complete transparency. The purpose of this study is to evaluate the translucency index of resin composites according to their chemical structure and to the light source used for curing. Our study was achieved on four commercial composite samples (30 mm × 2 mm) cured with two different lamps (Optilux - halogen bulb and Ultralight - LED). Measurements were made with a UV-VIS spectrophotometer, and the reflection spectrum was recorded in the 380-770 nm region on white and black, compared with a SPECTRALON standard white. For all materials cured with the LED lamp on the glossy sides, the best results were given by Tetric Evo Ceram followed by Filtek Supreme, RestacrilRO and Premise. The measurements made on samples cured with an Optilux lamp, to the smooth and rough sides of the samples, revealed that the highest index of translucency is provided by Tetric Evo Ceram on the smooth side, followed by Filtek Supreme, RestacrilRO and Premises. We can say that the translucency of the composites is mostly determined by the chemical composition of the material, which is observed from transmittance values recorded for each sample, and by the source of radiation applied on the sample.

The translucency of dental composites investigated by UV-VIS spectroscopy

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

Dumitrescu, L. Silaghi; Pastrav, O.; Prejmerean, C.

Translucency is the property of a material to partially transmit and diffuse incident light, and can be described as a partial opacity or a state between complete opacity and complete transparency. The purpose of this study is to evaluate the translucency index of resin composites according to their chemical structure and to the light source used for curing. Our study was achieved on four commercial composite samples (30 mm × 2 mm) cured with two different lamps (Optilux - halogen bulb and Ultralight - LED). Measurements were made with a UV-VIS spectrophotometer, and the reflection spectrum was recorded in themore » 380-770 nm region on white and black, compared with a SPECTRALON standard white. For all materials cured with the LED lamp on the glossy sides, the best results were given by Tetric Evo Ceram followed by Filtek Supreme, Restacril{sup RO} and Premise. The measurements made on samples cured with an Optilux lamp, to the smooth and rough sides of the samples, revealed that the highest index of translucency is provided by Tetric Evo Ceram on the smooth side, followed by Filtek Supreme, Restacril{sup RO} and Premises. We can say that the translucency of the composites is mostly determined by the chemical composition of the material, which is observed from transmittance values recorded for each sample, and by the source of radiation applied on the sample.« less

High-performance LED luminaire for sports hall

NASA Astrophysics Data System (ADS)

Lee, Xuan-Hao; Yang, Jin-Tsung; Chien, Wei-Ting; Chang, Jung-Hsuan; Lo, Yi-Chien; Lin, Che-Chu; Sun, Ching-Cherng

2015-09-01

In this paper, we present a luminaire design with anti-glare and energy-saving effects for sports hall. Compared with traditional lamps using in a badminton court, the average illuminance on the ground of the proposed LED luminaire is enhanced about 300%. Besides, the uniformity is obviously enhanced and improved. The switch-on speed of lighting in sports hall is greatly reduced from 5-10 minutes to 1 second. The simulation analysis and the corresponding experiment results are demonstrated.

Dimming LEDs with Phase-Cut Dimmers: The Specifier's Process for Maximizing Success

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

Miller, Naomi J.; Poplawski, Michael E.

2013-10-01

This report reviews how phase-cut dimmers work, how LEDs differ from the incandescent lamps that the dimmers were historically designed to control, and how these differences can lead to complications when trying to dim LEDs. Compatibility between a specific LED source and a specific phase-cut dimmer is often unknown and difficult to assess, and ensuring compatibility adds complexity to the design, specification, bidding, and construction observation phases for new buildings and major remodel projects. To maximize project success, this report provides both general guidance and step-by-step procedures for designing phase-controlled LED dimming on both new and existing projects, as wellmore » as real-world examples of how to use those procedures.« less

Suspended Silicon Microphotodiodes for Electrochemical and Biological Applications.

PubMed

Vargas-Estevez, Carolina; Duch, Marta; Duque, Marcos; Del Campo, Francisco Javier; Enriquez-Barreto, Lilian; Murillo, Gonzalo; Torras, Núria; Plaza, José A; Saura, Carlos A; Esteve, Jaume

2017-11-01

Local electric stimulation of tissues and cells has gained importance as therapeutic alternative in the treatment of many diseases. These alternatives aim to deliver a less invasively stimuli in liquid media, making imperative the development of versatile micro- and nanoscale solutions for wireless actuation. Here, a simple microfabrication process to produce suspended silicon microphotodiodes that can be activated by visible light to generate local photocurrents in their surrounding medium is presented. Electrical characterization using electrical probes confirms their diode behavior. To demonstrate their electrochemical performance, an indirect test is implemented in solution through photoelectrochemical reactions controlled by a white-LED lamp. Furthermore, their effects on biological systems are observed in vitro using mouse primary neurons in which the suspended microphotodiodes are activated periodically with white-LED lamp, bringing out observable morphological changes in neuronal processes. The results demonstrate a simplified and cost-effective wireless tool for photovoltaic current generation in liquid media at the microscale. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigations regarding the wet decontamination of fluorescent lamp waste using iodine in potassium iodide solutions

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

Tunsu, Cristian, E-mail: tunsu@chalmers.se; Ekberg, Christian; Foreman, Mark

Highlights: • A wet-based decontamination process for fluorescent lamp waste is proposed. • Mercury can be leached using iodine in potassium iodide solution. • The efficiency of the process increases with an increase in leachant concentration. • Selective leaching of mercury from rare earth elements is achieved. • Mercury is furthered recovered using ion exchange, reduction or solvent extraction. - Abstract: With the rising popularity of fluorescent lighting, simple and efficient methods for the decontamination of discarded lamps are needed. Due to their mercury content end-of-life fluorescent lamps are classified as hazardous waste, requiring special treatment for disposal. A simplemore » wet-based decontamination process is required, especially for streams where thermal desorption, a commonly used but energy demanding method, cannot be applied. In this study the potential of a wet-based process using iodine in potassium iodide solution was studied for the recovery of mercury from fluorescent lamp waste. The influence of the leaching agent’s concentration and solid/liquid ratio on the decontamination efficiency was investigated. The leaching behaviour of mercury was studied over time, as well as its recovery from the obtained leachates by means of anion exchange, reduction, and solvent extraction. Dissolution of more than 90% of the contained mercury was achieved using 0.025/0.05 M I{sub 2}/KI solution at 21 °C for two hours. The efficiency of the process increased with an increase in leachant concentration. 97.3 ± 0.6% of the mercury contained was dissolved at 21 °C, in two hours, using a 0.25/0.5 M I{sub 2}/KI solution and a solid to liquid ratio of 10% w/v. Iodine and mercury can be efficiently removed from the leachates using Dowex 1X8 anion exchange resin or reducing agents such as sodium hydrosulphite, allowing the disposal of the obtained solution as non-hazardous industrial wastewater. The extractant CyMe{sub 4}BTBP showed good removal of mercury, with an extraction efficiency of 97.5 ± 0.7% being achieved in a single stage. Better removal of mercury was achieved in a single stage using the extractants Cyanex 302 and Cyanex 923 in kerosene, respectively.« less

Cooling of High-Power LED Lamp Using a Commercial Paraffin Wax

NASA Astrophysics Data System (ADS)

Zmywaczyk, J.; Zbińkowski, P.; Smogór, H.; Olejnik, A.; Koniorczyk, P.

2017-03-01

Commercial paraffin wax used by Bolsius Nederland B.V. for manufacturing various kinds of candles was applied as a phase-change material (PCM) for cooling a 28 W high-power light emitting diode (LED) panel during its operation. The main problem arising during operation of an LED is thermal management. According to the manufacturer's datasheet specifications (BioSolution Ltd. www.biosolution.pl, the operating temperature range for the LED street lamp UL28W is (-30 {°}C) to (+40 {°}C). The object of the present study was an LED panel containing 28 pieces of high-power 1W LEDs connected in series (4 LEDs in each of the 7 rows) mounted on an aluminum plate of dimensions 80 mm by 135 mm. The tested aluminum plate was placed in a block made of aluminum with a hollow compartment containing Bolsius paraffin wax of density 914 kg\\cdot m^{-3} at room temperature. Temperatures were recorded using K-type thermocouples at selected locations of the tested LED panel for several values of the power supplied to it, while utilizing PCM and without it. As the manufacturer of Bolsius wax candles does not provide any data on the thermal properties of the material used, it was necessary to carry out micro-calorimetric research. Thermophysical properties of the paraffin wax such as the apparent specific heat, enthalpy of phase transition and temperature of phase change transition during heating and cooling were determined using the Netzsch DSC 214 Polyma. The Netzsch TG 209F3 Tarsus was used for TG/DTG measurements. DSC investigations revealed the following thermal transitions taking place during the first heating: solid-solid transition (onset 30.4 {°}C, peak at 40.9 {°}C), solid-liquid transition (onset 47.7 {°}C, peak at 54.9 {°}C, end at 58.3 {°}C), latent heat of energy storage 201 J\\cdot g^{-1}, apparent specific heat corresponding to peak at 41.5 {°}C (5.498 J\\cdot g^{-1}\\cdot K^{-1}). DTG investigations revealed that the decomposition of paraffin wax is a two-step process. At 283 {°}C there was observed a slightly slower decomposition (9.43 %\\cdot min^{-1}) than that at 323 {°}C (12.5 %\\cdot min^{-1}). The experimental results obtained upon cooling the high-power LED lamp during its operation can be applied to verify results of numerical modeling of the heat transfer problems with phase-change transitions. An attempt at modeling such a problem based on 1D fixed grid with variable time step approach was undertaken in this work.

Re-designing illumination level in printing working area

NASA Astrophysics Data System (ADS)

Wahyuni, D.; Tambunan, M.; Panjaitan, N.; Budiman, I.

2018-02-01

This research was conducted in four printing business in Medan city. The illumination level on the research object is very low around 30 Lux far below the required value of government regulation at 200 Lux. Poor lighting has an impact on the number of defective products that pass the inspection, so we need to improve the workspace lighting to improve the quality of work. The method of determining the measuring point follows SNI 16-7062-2004, and the measuring instrument used is 4 in 1 Environment Meter. The results show that almost all workspaces under study require improved lighting, because the light bulbs used are not able to meet the lighting needs. This research recommends improving the workspace lighting using LED (Light Emitting Diode) lights because it has high energy efficiency and relatively more lifetime compared to the existing lamp.

Energy efficiency effect on the public street lighting by using LED light replacement and kwh-meter installation at DKI Jakarta Province, Indonesia

NASA Astrophysics Data System (ADS)

Sudarmono, Panggih; Deendarlianto; Widyaparaga, Adhika

2018-05-01

Public street lighting consumes large energy for the public interest, but many street lights still do not use energy-saving technologies. In 2014, Provincial Government of DKI Jakarta operated 179,305 units of street lights. Of the number of installed armature, 92 % of them or 166,441 units are HPS (High-Pressure Sodium) armatures which are inefficient. In 2016, the Provincial Government of DKI Jakarta cut down the energy used for street lighting, by implementing the programs of kWh-meter installation in every street lighting panel and use energy-saving lamps equipped with the smart system. The Provincial Government of DKI Jakarta is registered with 6,399 customer IDs in PLN (State Owned Electric Company), and gradually carried out the kWh Meter installation and changes to the contract. The program to use energy-saving lights done by replacing the HPS armature that is not energy efficient to LED armature which is known to be energy efficient. Until the end of 2016, the number of armatures that has been replaced was 89,417 units. The research results on 25 samples of PLN customer IDs and the replacement of 2,162 units armature, showed that the energy efficiency through kWh meter installation and armature replacement reduce the power consumption from 330,414 kWh to 71,278 kWh or by 78.43%. Generally, there was a decrease in the value of electricity bill compared to the before the replacement. The program of kWh-meter installations and replacement of the armature has a payback period of 2.66 years.

Enhanced Output Power of Near-Ultraviolet Light-Emitting Diodes by p-GaN Micro-Rods

NASA Astrophysics Data System (ADS)

Wang, Dong-Sheng; Zhang, Ke-Xiong; Liang, Hong-Wei; Song, Shi-Wei; Yang, De-Chao; Shen, Ren-Sheng; Liu, Yang; Xia, Xiao-Chuan; Luo, Ying-Min; Du, Guo-Tong

2014-02-01

Near-ultraviolet (UV) InGaN/AlGaN light-emitting diodes (LEDs) are grown by low-pressure metal-organic chemical vapor deposition. The scanning electronic microscope image shows that the p-GaN micro-rods are formed above the interface of p-AlGaN/p-GaN due to the rapid growth rate of p-GaN in the vertical direction. The p-GaN micro-rods greatly increase the escape probability of photons inside the LED structure. Electroluminescence intensities of the 372 nm UV LED lamps with p-GaN micro rods are 88% higher than those of the flat surface LED samples.

Effect of the spectral emission energy of various UV sources on photochemical curing of unsaturated oligomeric ester coatings

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

Skubin, V.K.; Sazonov, A.P.; Torgonenko, V.A.

1988-11-10

In this paper, using the example of unsaturated oligomeric esters, the effect of UV radiation of various domestic sources on the rate of curing of coatings is investigated. For the investigations a 60% styrene solution of PN-15 grade unsaturated oligomeric ester based on an equimolar ratio of maleic anhydride and oxypropylated diphenylenepropene was used. Isobutyl ether of benzoin served as the photoinitiator. The following lamps were used as radiation sources: electrodeless high-frequency lamps of continuous action with additions of mercury, cadmium, and phosphorus; a DRKS-500 mercury-xenon-arc lamp; and a DRT-1000 tubular mercury-arc lamp. When choosing UV sources to increase themore » efficiency of photochemical decay of the initiator and the rate of curing of the coating it is necessary first of all to be guided by the distribution of the spectral energy of the lamp radiation and the UV absorption spectrum of the photoinitiator.« less

LED lighting for use in multispectral and hyperspectral imaging

USDA-ARS?s Scientific Manuscript database

Lighting for machine vision and hyperspectral imaging is an important component for collecting high quality imagery. However, it is often given minimal consideration in the overall design of an imaging system. Tungsten-halogens lamps are the most common source of illumination for broad spectrum appl...

Shining a light on LAMP assays--a comparison of LAMP visualization methods including the novel use of berberine.

PubMed

Fischbach, Jens; Xander, Nina Carolin; Frohme, Marcus; Glökler, Jörn Felix

2015-04-01

The need for simple and effective assays for detecting nucleic acids by isothermal amplification reactions has led to a great variety of end point and real-time monitoring methods. Here we tested direct and indirect methods to visualize the amplification of potato spindle tuber viroid (PSTVd) by loop-mediated isothermal amplification (LAMP) and compared features important for one-pot in-field applications. We compared the performance of magnesium pyrophosphate, hydroxynaphthol blue (HNB), calcein, SYBR Green I, EvaGreen, and berberine. All assays could be used to distinguish between positive and negative samples in visible or UV light. Precipitation of magnesium-pyrophosphate resulted in a turbid reaction solution. The use of HNB resulted in a color change from violet to blue, whereas calcein induced a change from orange to yellow-green. We also investigated berberine as a nucleic acid-specific dye that emits a fluorescence signal under UV light after a positive LAMP reaction. It has a comparable sensitivity to SYBR Green I and EvaGreen. Based on our results, an optimal detection method can be chosen easily for isothermal real-time or end point screening applications.

Experimental ultraviolet photocarcinogenesis: wavelength interactions and time-dose relationships.

PubMed

Forbes, P D; Davies, R E; Urbach, F

1978-12-01

Tumors were induced in the skin of SKH hairless mice by exposure to fluorescent FS sun lamps or to a long-arc xenon solar simulator. Tumores developed about equally well with varying amounts of UV-A radiation (lambda greater than 320 nm) given simultaneously. In contrast, incremental changes in the UV-B region (lambda less than 320 nm) led to substantial increases in carcinogenic effectiveness. A tumor-"initiating" dose of UV-B (4-10 wk of daily FS lamp exposures) was rendered less effective by subsequent exposures of the mice to UV-A (6 hr/day, F-40 T12BL lamps). The mechanism for this effect is not known. Most tumors induced by a short course (10 wk) of FS lamp exposure grew slowly or regressed, whereas mice exposed for a longer period (30 wk) developed more tumors, and many of those that appeared early grew aggressively. Effects of daily dose fractionation were less clear, and the subject requires further study. These and other variables are being tested in a program designed to yield useful information on the effects of changing spectrum, dose, and dose delivery rates on sunlight-induced cancer.

[Visual hygiene in LED lighting. Modern scientific imaginations].

PubMed

Deynego, V N; Kaptsov, V A

2014-01-01

There are considered a classic and modern paradigm of perception of light and its impact on human health. To consider the perception of light as a complex self-organizing synergistic system of compression of information in the process of its sequencing was supposed. This allowed to develop a complex of interrelated measures, which may become the basis for modern hygiene, and determine requirements for the led lamp with biologically adequate spectrum of the light, for which there were obtained patents in Russia, Europe and USA.

The responses of light interception, photosynthesis and fruit yield of cucumber to LED-lighting within the canopy.

PubMed

Trouwborst, Govert; Oosterkamp, Joke; Hogewoning, Sander W; Harbinson, Jeremy; van Ieperen, Wim

2010-03-01

Mathematical models of light attenuation and canopy photosynthesis suggest that crop photosynthesis increases by more uniform vertical irradiance within crops. This would result when a larger proportion of total irradiance is applied within canopies (interlighting) instead of from above (top lighting). These irradiance profiles can be generated by Light Emitting Diodes (LEDs). We investigated the effects of interlighting with LEDs on light interception, on vertical gradients of leaf photosynthetic characteristics and on crop production and development of a greenhouse-grown Cucumis sativus'Samona' crop and analysed the interaction between them. Plants were grown in a greenhouse under low natural irradiance (winter) with supplemental irradiance of 221 micromol photosynthetic photon flux m(-2) s(-1) (20 h per day). In the interlighting treatment, LEDs (80% Red, 20% Blue) supplied 38% of the supplemental irradiance within the canopy with 62% as top lighting by High-Pressure Sodium (HPS)-lamps. The control was 100% top lighting (HPS lamps). We measured horizontal and vertical light extinction as well as leaf photosynthetic characteristics at different leaf layers, and determined total plant production. Leaf mass per area and dry mass allocation to leaves were significantly greater but leaf appearance rate and plant length were smaller in the interlighting treatment. Although leaf photosynthetic characteristics were significantly increased in the lower leaf layers, interlighting did not increase total biomass or fruit production, partly because of a significantly reduced vertical and horizontal light interception caused by extreme leaf curling, likely because of the LED-light spectrum used, and partly because of the relatively low irradiances from above.

Soybean stem growth under high-pressure sodium with supplemental blue lighting

NASA Technical Reports Server (NTRS)

Wheeler, R. M.; Mackowiak, C. L.; Sager, J. C.

1991-01-01

To study high-pressure sodium (HPS) lamps used for plant lighting because of their high energy conversion efficiencies, 'McCall' soybean plants were grown for 28 days in growth chambers utilizing HPS lamps, with/without supplemental light from blue phosphor fluorescent lamps. Total photosynthetic photon flux levels, including blue fluorescent, were maintained near 300 or 500 micromol/sq m s. Results indicate that employment of HPS or other blue-deficient sources for lighting at low to moderate photosynthetic photon flux levels may cause abnormal stem elongation, but this can be prevented by the addition of a small amount of supplemental blue light.

The influence of flash lamp annealing on the minority carrier lifetime of Czochralski silicon wafers

NASA Astrophysics Data System (ADS)

Kissinger, G.; Kot, D.; Sattler, A.

2014-02-01

Flash lamp annealing of moderately B-doped CZ silicon wafers for 20 ms with a normalized irradiance of about 0.9 was used to efficiently suppress oxygen precipitation during subsequent thermal processing. In this way, the minority carrier lifetime measured at high injection level by microwave-detected photo-conductance decay (μ-PCD) was increased from about 30 microseconds to about 300 microseconds after a thermal process consisting of 780 °C 3 h + 1000 °C 16 h. The grown-in oxide precipitate nuclei were shrunken to a subcritical size during the flash lamp anneal which prevents further growth during subsequent thermal processing.

Fundamental studies on a heat driven lamp

NASA Technical Reports Server (NTRS)

Lawless, J. L.

1985-01-01

A detailed theoretical study of a heat-driven lamp has been performed. This lamp uses a plasma produced in a thermionic diode. The light is produced by the resonance transition of cesium. An important result of this study is that up to 30% of the input heat is predicted to be converted to light in this device. This is a major improvement over ordinary thermionic energy converters in which only approx. 1% is converted to resonance radiation. Efficiencies and optimum inter-electrode spacings have been found as a function of cathode temperature and the radiative escape factor. The theory developed explains the operating limits of the device.

SELF-CONTAINED HUMAN AND SOLAR POWERED LED LIGHTING SYSTEM FOR USE IN THE DEVELOPING WORLD

EPA Science Inventory

Approximately 49% of rural households and 14% of urban households in developing nations live without electricity, most of who rely by fuel-based lamps which are inefficient, costly to operate, and produce large amounts of potentially harmful byproducts and green house gas emis...

Tiny Tool Converts Light to Electricity

ERIC Educational Resources Information Center

Kamata, Masahiro; Tamamura, Yuna

2010-01-01

In Japan, junior high school students learn about energy conversion between kinetic and potential energy. In addition, they learn about energy conversion among different kinds of energy, such as mechanical, electrical, thermal, light and chemical. As for the conversion between electrical and light energy, teachers usually use lamps or LEDs to…

[Principle of LAMP method--a simple and rapid gene amplification method].

PubMed

Ushikubo, Hiroshi

2004-06-01

So far nucleic acid test (NAT) has been employed in various fields, including infectious disease diagnoses. However, due to its complicated procedures and relatively high cost, it has not been widely utilized in many actual diagnostic applications. We have therefore developed a simple and rapid gene amplification technology, Loop-mediated Isothermal Amplification (LAMP) method, which has shown prominent results of surpassing the performance of the conventional gene amplification methods. LAMP method acquires three main features: (1) all reaction can be carried out under isothermal conditions; (2) the amplification efficiency is extremely high and tremendous amount of amplification products can be obtained; and (3) the reaction is highly specific. Furthermore, developed from the standard LAMP method, a rapid LAMP method, by adding in the loop primers, can reduce the amplification time from the previous 1 hour to less than 30 minutes. Enormous amount of white precipitate of magnesium pyrophosphate is produced as a by-product of the amplification, therefore, direct visual detection is possible without using any reaction indicators and detection equipments. We believe LAMP technology, with the integration of these features, can rightly apply to clinical genetic testing, food and environmental analysis, as well as NAT in different fields.

High pressure neon arc lamp

DOEpatents

Sze, Robert C.; Bigio, Irving J.

2003-07-15

A high pressure neon arc lamp and method of using the same for photodynamic therapies is provided. The high pressure neon arc lamp includes a housing that encloses a quantity of neon gas pressurized to about 500 Torr to about 22,000 Torr. At each end of the housing the lamp is connected by electrodes and wires to a pulse generator. The pulse generator generates an initial pulse voltage to breakdown the impedance of the neon gas. Then the pulse generator delivers a current through the neon gas to create an electrical arc that emits light having wavelengths from about 620 nanometers to about 645 nanometers. A method for activating a photosensitizer is provided. Initially, a photosensitizer is administered to a patient and allowed time to be absorbed into target cells. Then the high pressure neon arc lamp is used to illuminate the target cells with red light having wavelengths from about 620 nanometers to about 645 nanometers. The red light activates the photosensitizers to start a chain reaction that may involve oxygen free radicals to destroy the target cells. In this manner, a high pressure neon arc lamp that is inexpensive and efficiently generates red light useful in photodynamic therapy is provided.

Loop-mediated isothermal amplification (LAMP) assay for the diagnosis of fasciolosis in sheep and its application under field conditions.

PubMed

Martínez-Valladares, María; Rojo-Vázquez, Francisco Antonio

2016-02-05

Loop-mediated isothermal amplification (LAMP) is a very specific, efficient, and rapid gene amplification procedure in which the reaction can run at a constant temperature. In the current study we have developed a LAMP assay to improve the diagnosis of Fasciola spp. in the faeces of sheep. After the optimisation of the LAMP assay we have shown similar results between this technique and the standard PCR using the outer primers of the LAMP reaction. In both cases the limit of detection was 10 pg; also, the diagnosis of fasciolosis was confirmed during the first week post-infection in experimental infected sheep by both techniques. In eight naturally infected sheep, the infection with F. hepatica was confirmed in all animals before a treatment with triclabendazole and on day 30 post treatment in two sheep using the LAMP assay; however, when we carried out the standard PCR with the outer primers, the results before treatment were the same but on day 30 post-treatment the infection was only confirmed in one out of the two sheep. On the other hand, the standard PCR took around 3 h to obtain a result, comparing with 1 h and 10 min for the LAMP assay. The LAMP assay described here could be a good alternative to conventional diagnostic methods to detect F. hepatica in faeces since it solves the drawbacks of the standard PCR.

Modeling the effects of phosphor converted LED lighting to the night sky of the Haleakala Observatory, Hawaii

NASA Astrophysics Data System (ADS)

Aubé, M.; Simoneau, A.; Wainscoat, R.; Nelson, L.

2018-05-01

The goal of this study is to evaluate the current level of light pollution in the night sky at the Haleakala Observatory on the island of Maui in Hawaii. This is accomplished with a numerical model that was tested in the first International Dark Sky Reserve located in Mont-Mégantic National Park in Canada. The model uses ground data on the artificial light sources present in the region of study, geographical data, and remotely sensed data for: 1) the nightly upward radiance; 2) the terrain elevation; and, 3) the ground spectral reflectance of the region. The results of the model give a measure of the current state of the sky spectral radiance at the Haleakala Observatory. Then, using the current state as a reference point, multiple light conversion plans are elaborated and evaluated using the model. We can thus estimate the expected impact of each conversion plan on the night sky radiance spectrum. A complete conversion to white (LEDs) with (CCT) of 4000K and 3000K are contrasted with a conversion using (PC) amber (LEDs). We include recommendations concerning the street lamps to be used in sensitive areas like the cities of Kahului and Kihei and suggest best lighting practices related to the color of lamps used at night.

A cost-effective quasi-distributed liquid leakage sensor based on the polymer optical fiber and flexible lamp belt with LEDs.

PubMed

Zhang, Yingzi; Hou, Yulong; Zhang, Yanjun; Hu, Yanjun; Zhang, Liang; Gao, Xiaolong; Zhang, Huixin; Liu, Wenyi

2018-04-16

A quasi-distributed liquid leakage (QDLL) sensor in local area is proposed and experimentally demonstrated, providing a real-time yet low-cost method than the existing local QDLL sensor. The sensor mainly consists of a flexible lamp belt (FLB) with light-emitting diodes (LEDs) and a polymer optical fiber (POF) processed with side-coupling structures. The side-coupling structures are illuminated by the LEDs one by one, forming a series of sensing probes. The lights are side-coupled into the POF through the side-coupling structure and pulse sequences are obtained from the power meters connected to the both ends of the POF. Each pulse represents a sensing probe, and the intensity of them increase when the coupling medium changes from air to liquid. The location of the leakage incident can be got by the position of each pulse in its output sequence. The influence of different side-coupling structures on side-coupling ratio are investigated. The experiment results validate the detection and localization abilities of the QDLL sensor along a 1 m-long POF with a spatial resolution of 0.1 m, which can be improved by adjusting the side-coupling structure. Furthermore, the temperature dependence is studied and can be compensated.

Scientific Verification Test of Orbitec Deployable Vegetable Production System for Salad Crop Growth on ISS- Gas Exchange System design and function

NASA Technical Reports Server (NTRS)

Eldemire, Ashleigh

2007-01-01

The ability to produce and maintain salad crops during long term missions would be a great benefit to NASA; the renewable food supply would save cargo space, weight and money. The ambient conditions of previous ground controlled crop plant experiments do not reflect the microgravity and high CO2 concentrations present during orbit. It has been established that microgravity does not considerably alter plant growth. (Monje, Stutte, Chapman, 2005). To support plants in a space-craft environment efficient and effective lighting and containment units are necessary. Three lighting systems were previously evaluated for radish growth in ambient air; fluorescent lamps in an Orbitec Biomass Production System Educational (BPSE), a combination of red, blue, and green LED's in a Deployable Vegetable Production System (Veggie), and a combination of red and blue LED's in a Veggie. When mass measurements compared the entire possible growing area vs. power consumed by the respective units, the Veggies clearly exceeded the BPSE indicating that the LED units were a more resource efficient means of growing radishes under ambient conditions in comparison with fluorescent lighting. To evaluate the most productive light treatment system for a long term space mission a more closely simulated ISS environment is necessary. To induce a CO2 dense atmosphere inside the Veggie's and BPSE a gas exchange system has been developed to maintain a range of 1000-1200 ppm CO2 during a 21-day light treatment experiment. This report details the design and function of the gas exchange system. The rehabilitation, trouble shooting, maintenance and testing of the gas exchange system have been my major assignments. I have also contributed to the planting, daily measurements and harvesting of the radish crops 21-day light treatment verification test.

Color speckle in laser displays

NASA Astrophysics Data System (ADS)

Kuroda, Kazuo

2015-07-01

At the beginning of this century, lighting technology has been shifted from discharge lamps, fluorescent lamps and electric bulbs to solid-state lighting. Current solid-state lighting is based on the light emitting diodes (LED) technology, but the laser lighting technology is developing rapidly, such as, laser cinema projectors, laser TVs, laser head-up displays, laser head mounted displays, and laser headlamps for motor vehicles. One of the main issues of laser displays is the reduction of speckle noise1). For the monochromatic laser light, speckle is random interference pattern on the image plane (retina for human observer). For laser displays, RGB (red-green-blue) lasers form speckle patterns independently, which results in random distribution of chromaticity, called color speckle2).

Modeling of a Ne/Xe dielectric barrier discharge excilamp for improvement of VUV radiation production

NASA Astrophysics Data System (ADS)

Khodja, K.; Belasri, A.; Loukil, H.

2017-08-01

This work is devoted to excimer lamp efficiency optimization by using a homogenous discharge model of a dielectric barrier discharge in a Ne-Xe mixture. The model includes the plasma chemistry, electrical circuit, and Boltzmann equation. In this paper, we are particularly interested in the electrical and kinetic properties and light output generated by the DBD. Xenon is chosen for its high luminescence in the range of vacuum UV radiation around 173 nm. Our study is motivated by interest in this type of discharge in many industrial applications, including the achievement of high light output lamps. In this work, we used an applied sinusoidal voltage, frequency, gas pressure, and concentration in the ranges of 2-8 kV, 10-200 kHz, 100-800 Torr, and 10-50%, respectively. The analyzed results concern the voltage V p across the gap, the dielectric voltage V d, the discharge current I, and the particles densities. We also investigated the effect of the electric parameters and xenon concentration on the lamp efficiency. This investigation will allow one to find out the appropriate parameters for Ne/Xe DBD excilamps to improve their efficiency.

Study on excitation and fluorescence spectrums of Japanese citruses to construct machine vision systems for acquiring fluorescent images

NASA Astrophysics Data System (ADS)

Momin, Md. Abdul; Kondo, Naoshi; Kuramoto, Makoto; Ogawa, Yuichi; Shigi, Tomoo

2011-06-01

Research was conducted to acquire knowledge of the ultraviolet and visible spectrums from 300 -800 nm of some common varieties of Japanese citrus, to investigate the best wave-lengths for fluorescence excitation and the resulting fluorescence wave-lengths and to provide a scientific background for the best quality fluorescent imaging technique for detecting surface defects of citrus. A Hitachi U-4000 PC-based microprocessor controlled spectrophotometer was used to measure the absorption spectrum and a Hitachi F-4500 spectrophotometer was used for the fluorescence and excitation spectrums. We analyzed the spectrums and the selected varieties of citrus were categorized into four groups of known fluorescence level, namely strong, medium, weak and no fluorescence.The level of fluorescence of each variety was also examined by using machine vision system. We found that around 340-380 nm LEDs or UV lamps are appropriate as lighting devices for acquiring the best quality fluorescent image of the citrus varieties to examine their fluorescence intensity. Therefore an image acquisition device was constructed with three different lighting panels with UV LED at peak 365 nm, Blacklight blue lamps (BLB) peak at 350 nm and UV-B lamps at peak 306 nm. The results from fluorescent images also revealed that the findings of the measured spectrums worked properly and can be used for practical applications such as for detecting rotten, injured or damaged parts of a wide variety of citrus.

Employing the conventional edge-lighting technology into ultraviolet-range: a preliminary study by optical simulation

NASA Astrophysics Data System (ADS)

Ye, Linchao; Belloni, Paola; Möller, Knut

2011-10-01

Within the framework of a project conducted together with an industrial partner, a self-disinfecting operation interface with a glass panel is being developed. The concept of self-disinfection is based on the exploitation of the photocatalytical effect induced by a TiO2-coating on the glass surface under UV(A) light, which would make the touch screen antimicrobial. High-power UV-LEDs instead of conventional UV-lamps have been employed as light source. The main goal and challenge of the optical design is to generate an efficient and preferably homogeneous UV field on the TiO2-coated side while keeping the UV-LEDs concealed, i.e. invisible to the user. Therefore common backlighting systems have been used as reference and modified to meet the concrete requirements. Primary analysis and optical simulations have been performed with the software LightTools®. Several patterns for light redirection (i.e. 3D-spherical texture, 3D-rectangular texture and 2D-circular serigraph) have been investigated, compared and evaluated. Finally the pattern design which both fulfills all the predefined boundary conditions and simultaneously reduces the costs has been chosen.

UV Lamp as a Facile Ozone Source for Structural Analysis of Unsaturated Lipids Via Electrospray Ionization-Mass Spectrometry

NASA Astrophysics Data System (ADS)

Stinson, Craig A.; Zhang, Wenpeng; Xia, Yu

2017-12-01

Ozonolysis of alkene functional groups is a type of highly specific and effective chemical reaction, which has found increasing applications in structural analysis of unsaturated lipids via coupling with mass spectrometry (MS). In this work, we utilized a low-pressure mercury lamp (6 W) to initiate ozonolysis inside electrospray ionization (ESI) sources. By placing the lamp near a nanoESI emitter that partially transmits 185 nm ultraviolet (UV) emission from the lamp, dissolved dioxygen in the spray solution was converted into ozone, which subsequently cleaved the double bonds within fatty acyls of lipids. Solvent conditions, such as presence of water and acid solution pH, were found to be critical in optimizing ozonolysis yields. Fast (on seconds time scale) and efficient (50%-100% yield) ozonolysis was achieved for model unsaturated phospholipids and fatty acids with UV lamp-induced ozonolysis incorporated on a static and an infusion nanoESI source. The method was able to differentiate double bond location isomers and identify the geometry of the double bond based on yield. The analytical utility of UV lamp-induced ozonolysis was further demonstrated by implementation on a liquid chromatography (LC)-MS platform. Ozonolysis was effected in a flow microreactor that was made from ozone permeable tubing, so that ambient ozone produced by the lamp irradiation could diffuse into the reactor and induce online ozonolysis post-LC separation and before ESI-MS.

High frequency inductive lamp and power oscillator

DOEpatents

MacLennan, Donald A.; Turner, Brian P.; Dolan, James T.; Kirkpatrick, Douglas A.; Leng, Yongzhang

2000-01-01

A high frequency inductively coupled electrodeless lamp includes an excitation coil with an effective electrical length which is less than one half wavelength of a driving frequency applied thereto, preferably much less. The driving frequency may be greater than 100 MHz and is preferably as high as 915 MHz. Preferably, the excitation coil is configured as a non-helical, semi-cylindrical conductive surface having less than one turn, in the general shape of a wedding ring. At high frequencies, the current in the coil forms two loops which are spaced apart and parallel to each other. Configured appropriately, the coil approximates a Helmholtz configuration. The lamp preferably utilizes an bulb encased in a reflective ceramic cup with a pre-formed aperture defined therethrough. The ceramic cup may include structural features to aid in alignment and/or a flanged face to aid in thermal management. The lamp head is preferably an integrated lamp head comprising a metal matrix composite surrounding an insulating ceramic with the excitation integrally formed on the ceramic. A novel solid-state oscillator preferably provides RF power to the lamp. The oscillator is a single active element device capable of providing over 70 watts of power at over 70% efficiency. Various control circuits may be employed to match the driving frequency of the oscillator to a plurality of tuning states of the lamp.

Uniformity of LED light illumination in application to direct imaging lithography

NASA Astrophysics Data System (ADS)

Huang, Ting-Ming; Chang, Shenq-Tsong; Tsay, Ho-Lin; Hsu, Ming-Ying; Chen, Fong-Zhi

2016-09-01

Direct imaging has widely applied in lithography for a long time because of its simplicity and easy-maintenance. Although this method has limitation of lithography resolution, it is still adopted in industries. Uniformity of UV irradiance for a designed area is an important requirement. While mercury lamps were used as the light source in the early stage, LEDs have drawn a lot of attention for consideration from several aspects. Although LED has better and better performance, arrays of LEDs are required to obtain desired irradiance because of limitation of brightness for a single LED. Several effects are considered that affect the uniformity of UV irradiance such as alignment of optics, temperature of each LED, performance of each LED due to production uniformity, and pointing of LED module. Effects of these factors are considered to study the uniformity of LED Light Illumination. Numerical analysis is performed by assuming a serious of control factors to have a better understanding of each factor.

Continuous microalgal cultivation in a laboratory-scale photobioreactor under seasonal day-night irradiation: experiments and simulation.

PubMed

Bertucco, Alberto; Beraldi, Mariaelena; Sforza, Eleonora

2014-08-01

In this work, the production of Scenedesmus obliquus in a continuous flat-plate laboratory-scale photobioreactor (PBR) under alternated day-night cycles was tested both experimentally and theoretically. Variation of light intensity according to the four seasons of the year were simulated experimentally by a tunable LED lamp, and effects on microalgal growth and productivity were measured to evaluate the conversion efficiency of light energy into biomass during the different seasons. These results were used to validate a mathematical model for algae growth that can be applied to simulate a large-scale production unit, carried out in a flat-plate PBR of similar geometry. The cellular concentration in the PBR was calculated in both steady-state and transient conditions, and the value of the maintenance kinetic term was correlated to experimental profiles. The relevance of this parameter was finally outlined.

Instantaneous and efficient surface wave excitation of a low pressure gas or gases

DOEpatents

Levy, Donald J.; Berman, Samuel M.

1988-01-01

A system for instantaneously ionizing and continuously delivering energy in the form of surface waves to a low pressure gas or mixture of low pressure gases, comprising a source of rf energy, a discharge container, (such as a fluorescent lamp discharge tube), an rf shield, and a coupling device responsive to rf energy from the source to couple rf energy directly and efficiently to the gas or mixture of gases to ionize at least a portion of the gas or gases and to provide energy to the gas or gases in the form of surface waves. The majority of the rf power is transferred to the gas or gases near the inner surface of the discharge container to efficiently transfer rf energy as excitation energy for at least one of the gases. The most important use of the invention is to provide more efficient fluorescent and/or ultraviolet lamps.

Characterization of particulate matter size distributions and indoor concentrations from kerosene and diesel lamps.

PubMed

Apple, J; Vicente, R; Yarberry, A; Lohse, N; Mills, E; Jacobson, A; Poppendieck, D

2010-10-01

Over one-quarter of the world's population relies on fuel-based lighting. Kerosene lamps are often located in close proximity to users, potentially increasing the risk for respiratory illnesses and lung cancer. Particulate matter concentrations resulting from cook stoves have been extensively studied in the literature. However, characterization of particulate concentrations from fuel-based lighting has received minimal attention. This research demonstrates that vendors who use a single simple wick lamp in high-air-exchange market kiosks will likely be exposed to PM(2.5) concentrations that are an order of magnitude greater than ambient health guidelines. Using a hurricane lamp will reduce exposure to PM(2.5) and PM(10) concentrations by an order of magnitude compared to using a simple wick lamp. Vendors using a single hurricane or pressure lamp may not exceed health standards or guidelines for PM(2.5) and PM(10), but will be exposed to elevated 0.02-0.3 μm particle concentrations. Vendors who change from fuel-based lighting to electric lighting technology for enhanced illumination will likely gain the ancillary health benefit of reduced particulate matter exposure. Vendors exposed only to ambient and fuel-based lighting particulate matter would see over an 80% reduction in inhaled PM(2.5) mass if they switched from a simple wick lamp to an electric lighting technology. Changing lighting technologies to achieve increased efficiency and energy service levels can provide ancillary health benefits. The cheapest, crudest kerosene lamps emit the largest amounts of PM(2.5). Improving affordability and access to better lighting options (hurricane or pressure lamps and lighting using grid or off-grid electricity) can deliver health benefits for a large fraction of the world's population, while reducing the economic and environmental burden of the current fuel-based lighting technologies.

Heat transfer properties and thermal cure of glass-ionomer dental cements.

PubMed

Gavic, Lidia; Gorseta, Kristina; Glavina, Domagoj; Czarnecka, Beata; Nicholson, John W

2015-10-01

Under clinical conditions, conventional glass-ionomer dental cements can be cured by application of heat from dental cure lamps, which causes acceleration in the setting. In order for this to be successful, such heat must be able to spread sufficiently through the cement to enhance cure, but not transmit heat so effectively that the underlying dental pulp of the tooth is damaged. The current study was aimed at measuring heat transfer properties of modern restorative glass-ionomers to determine the extent to which they meet these twin requirements. Three commercial glass ionomer cements (Ionofil Molar, Ketac Molar and Equia™ Fill) were used in association with three different light emitting diode cure lamps designed for clinical use. In addition, for each cement, one set of specimens was allowed to cure without application of a lamp. Temperature changes were measured at three different depths (2, 3 and 4 mm) after cure times of 20, 40 and 60 s. The difference among the tested groups was evaluated by ANOVA (P < 0.05) and post hoc Newman-Keuls test. All brands of glass-ionomer showed a small inherent setting exotherm in the absence of heat irradiation, but much greater temperature increases when exposed to the cure lamp. However, temperature rises did not exceed 12.9 °C. Application of the cure lamp led to the establishment of a temperature gradient throughout each specimen. Differences were typically significant (P < 0.05) and did not reflect the nominal power of the lamps, because those lamps have variable cooling systems, and are designed to optimize light output, not heating effect. Because the thermal conductivity of glass-ionomers is low, temperature rises at 4 mm depths were much lower than at 2 mm. At no time did the temperature rise sufficiently to cause concern about potential damage to the pulp.

Method and apparatus for powering an electrodeless lamp with reduced radio frequency interference

DOEpatents

Simpson, James E.

1999-01-01

An electrodeless lamp waveguide structure includes tuned absorbers for spurious RF signals. A lamp waveguide with an integral frequency selective attenuation includes resonant absorbers positioned within the waveguide to absorb spurious out-of-band RF energy. The absorbers have a negligible effect on energy at the selected frequency used to excite plasma in the lamp. In a first embodiment, one or more thin slabs of lossy magnetic material are affixed to the sidewalls of the waveguide at approximately one quarter wavelength of the spurious signal from an end wall of the waveguide. The positioning of the lossy material optimizes absorption of power from the spurious signal. In a second embodiment, one or more thin slabs of lossy magnetic material are used in conjunction with band rejection waveguide filter elements. In a third embodiment, one or more microstrip filter elements are tuned to the frequency of the spurious signal and positioned within the waveguide to couple and absorb the spurious signal's energy. All three embodiments absorb negligible energy at the selected frequency and so do not significantly diminish the energy efficiency of the lamp.

Method and apparatus for powering an electrodeless lamp with reduced radio frequency interference

DOEpatents

Simpson, J.E.

1999-06-08

An electrodeless lamp waveguide structure includes tuned absorbers for spurious RF signals. A lamp waveguide with an integral frequency selective attenuation includes resonant absorbers positioned within the waveguide to absorb spurious out-of-band RF energy. The absorbers have a negligible effect on energy at the selected frequency used to excite plasma in the lamp. In a first embodiment, one or more thin slabs of lossy magnetic material are affixed to the sidewalls of the waveguide at approximately one quarter wavelength of the spurious signal from an end wall of the waveguide. The positioning of the lossy material optimizes absorption of power from the spurious signal. In a second embodiment, one or more thin slabs of lossy magnetic material are used in conjunction with band rejection waveguide filter elements. In a third embodiment, one or more microstrip filter elements are tuned to the frequency of the spurious signal and positioned within the waveguide to couple and absorb the spurious signal's energy. All three embodiments absorb negligible energy at the selected frequency and so do not significantly diminish the energy efficiency of the lamp. 18 figs.

[Evaluation of efficiency of traps baited with frequency trembler grid lamps and trap plants for control Heortia vitessoides infectwed in Aquilaria sinensis].

PubMed

Qiao, Hai-Li; Xu, Chang-Qing; Xu, Rong; Guo, Kun; Wei, Jian-He; Li, Xiang-Ming; Chen, Jun

2016-06-01

Heortia vitessoides has been a serious defoliating pest of Aquilaria sinensis forests in recent years.The adults displayed strong tropism to the frequency trembler grid lamps and the nectar source plants.The favorite nectar source plants of H.vitessoides adults as the trap plants and the frequency trembler grid lamps in the integrated management of H.vitessoides were studied in the adult eclosion period through both the laboratory and field.The results showed that Kuhnia rosmarnifolia and Santalum album plants showed strong attraction to the H.vitessoides adults, with significant differences among the different nectar source plants.K.rosmarnifolia and S.album as trap plants with board type of planting area to total planting area of 5%-10%, and the frequency trembler grid lamps trapped significantly more adults of H.vitessoides. These results suggested that the frequency trembler grid lamps and trap plants could play an important role in the integrated management of the pest H.vitessoides of A.sinensis. Copyright© by the Chinese Pharmaceutical Association.

Investigation of breakdown processes in automotive HID lamps

NASA Astrophysics Data System (ADS)

Bergner, Andre; Hoebing, Thomas; Ruhrmann, Cornelia; Mentel, Juergen; Awakowicz, Peter

2011-10-01

HID lamps are used for applications where high lumen output levels are required. Car headlights are a special field of HID lamp application. For security reasons and lawful regulations these lamps have to have a fast run-up phase and the possibility of hot re-strike. Therefore the background gas pressure amounts to 1.5 MPa xenon. But this high background gas pressure has the disadvantage that the ignition voltage becomes quite high due to Paschen's law. For that reason this paper deals with the investigation of the breakdown process of HID lamps for automotive application. The ignition is investigated by electrical as well as optical methods. Ignition voltage and current are measured on a nanosecond time scale and correlated with simultaneous phase resolved high speed photography done by an ICCD camera. So the ignition process can be observed from the first light emission until to the formation of whole discharge channel. The authors gratefully acknowledge the financial support by BMBF within the European project 'SEEL - Solutions for Energy Efficient Lighting' (FKZ: 13N11265). Furthermore the author would like to thank Philips Lighting (Aachen) for valuable discussions.

Multi-LED parallel transmission for long distance underwater VLC system with one SPAD receiver

NASA Astrophysics Data System (ADS)

Wang, Chao; Yu, Hong-Yi; Zhu, Yi-Jun; Wang, Tao; Ji, Ya-Wei

2018-03-01

In this paper, a multiple light emitting diode (LED) chips parallel transmission (Multi-LED-PT) scheme for underwater visible light communication system with one photon-counting single photon avalanche diode (SPAD) receiver is proposed. As the lamp always consists of multi-LED chips, the data rate could be improved when we drive these multi-LED chips parallel by using the interleaver-division-multiplexing technique. For each chip, the on-off-keying modulation is used to reduce the influence of clipping. Then a serial successive interference cancellation detection algorithm based on ideal Poisson photon-counting channel by the SPAD is proposed. Finally, compared to the SPAD-based direct current-biased optical orthogonal frequency division multiplexing system, the proposed Multi-LED-PT system could improve the error-rate performance and anti-nonlinearity performance significantly under the effects of absorption, scattering and weak turbulence-induced channel fading together.

ATR technique, an appropriate method for determining the degree of conversion in dental giomers

NASA Astrophysics Data System (ADS)

Prejmerean, Cristina; Prodan, Doina; Vlassa, Mihaela; Streza, Mihaela; Buruiana, Tinca; Colceriu, Loredana; Prejmerean, Vasile; Cuc, Stanca; Moldovan, Marioara

2016-12-01

Dental light-curing giomers were developed to combine the favourable properties of diacrylic resin composites (DRCs) and glass-ionomer cements (GICs) in a single material and to eliminate their inherent drawbacks. Giomers are characterized by their aesthetic appearance, high mechanical properties, adhesion to dental tissues as well as fluoride release and recharge abilities. The qualities of the giomers are greatly influenced by the level of conversion of the component resins. Infrared spectroscopy is one of the most largely used techniques for the determination of the degree of conversion in resin-based dental materials. However different results were obtained due to the performances of the used methods. The present work presents the determination of conversion degree in a series of dental copolymers and their corresponding giomers using transmission Fourier transform infrared spectroscopy (FTIR) and an attenuated total reflection technique (ATR) technique, respectively, the main aim being the study of the influence of the materials composition and of the light curing modes upon the achieved conversion in the cured giomers. Beautifil II commercial giomer was used as a control. A halogen lamp and a diode-blue LED lamp were used for the curing of the materials. The results showed that the composition of the resins greatly influenced the conversion. The highest conversions (up to 79%) were obtained in the case of the experimental giomers which contained the experimental Bis-GMA urethane analogue, followed by the Beautifil II giomer (61%) and experimental giomers based on commercial Bis-GMA (up to 50%), respectively. The resins light-cured by using the diode-blue LED lamp presented slightly higher conversions than the resins cured by halogen lamp. The study demonstrates the possibility to evaluate easily and reproducibly the conversion in light-curing composite materials with complex chemical composition and structure, particularly in the case of giomers by using the ATR technique.

In mold laser welding for high precision polymer based optical components

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

Oliveira, N., E-mail: id2694@alunos.uminho.pt, E-mail: pontes@dep.uminho.pt; Pontes, A. J., E-mail: id2694@alunos.uminho.pt, E-mail: pontes@dep.uminho.pt

2014-05-15

To assemble a complete subsystem as a rear lamp, is necessary to have different machines and to perform several tasks. This necessity obliges the companies to have large structures to support all the assembling process. These huge structures are very costly and have as a consequence the reduction of the competitiveness of the companies. The process presented in this document has the intention of reducing the number of tasks needed to produce the final subsystem/product. To achieve this goal were combined several technologies, as in-mould assembling, laser welding and LEDs (light-emitting diode). One of the advantages of this process wasmore » the utilization of only one injection molding machine with three injection units to do all the assembling process. To achieve the main objective, firstly, the rear lamp was designed according to with the legislation of UNECE Vehicle Regulations - 1958 Agreements; Regulation No. 50 -Rev.2 - Position lamps, stop lamps, direction indicators for motorcycles. Posterior several polymeric materials were studied at different levels. Initial were studied several concentrations of carbon nanotubes mixed with PC (polycarbonate). This had the objective of determine, if these materials are suitable to conduct the necessary electric current to turn on the different LEDs. One of the main advantages of this process is the use of the laser transmission welded process. Since, with this welding technology is possible reduce the complexity of the final part. To understand the potentialities of this technology a combination of two materials was studied. The studied showed that all materials presented a high transparency to the laser beam. In terms of weld process, the study showed that the best welding conditions are the lowest velocity, diameter and power. With these studies was possible conclude that this new process is suitable to be implemented at the industrial level.« less

SOLAR-POWERED LED LANTERNS FOR THE REPLACEMENT OF OIL LAMPS IN THE DEVELOPING WORLD

EPA Science Inventory

The design process yielded an inexpensive yet highly useful lantern design which is attuned to the needs of the impoverished population. Keeping in mind the $20 off-the-shelf cost limit, the bulk-manufacturing cost was limited to $10 in order to allow for overhead (profit, tra...

405 nm diode laser, halogen lamp and LED device comparison in dental composites cure: an "in vitro" experimental trial.

PubMed

Fornaini, C; Lagori, G; Merigo, E; Rocca, J-P; Chiusano, M; Cucinotta, A

2015-12-30

A 405 nm diode laser is indicated for composite materials polymerizing, thanks to the recent evolution in their compositions, absorbing in blue part of the spectrum. The purpose of this research was to evaluate its performance on two different kinds of composite resins. Two different composites were polymerized with a traditional halogen lamp, a LED device and a 405 nm diode laser. The depth of the cure, the volumetric shrinkage, and the degree of the conversion (DC%) of the double bond during the curing process were measured. One-way ANOVA test, Kruskal-Wallis tests, and Dunn comparison tests were used for statistic analysis. Regarding the depth of polymerization, the laser had the worst performance on one composite while on the other, no significant difference with the other devices was observed. The volumetric shrinkage showed that laser produced the lowest change in both of the composites. The DC% measure confirmed these findings. Based on the results of this preliminary study, it is not possible to recommend the 405 nm diode laser for the polymerization of dental composites.

Absolute detector-based spectrally tunable radiant source using digital micromirror device and supercontinuum fiber laser.

PubMed

Li, Zhigang; Wang, Xiaoxu; Zheng, Yuquan; Li, Futian

2017-06-10

High-accuracy absolute detector-based spectroradiometric calibration techniques traceable to cryogenic absolute radiometers have made progress rapidly in recent decades under the impetus of atmospheric quantitative spectral remote sensing. A high brightness spectrally tunable radiant source using a supercontinuum fiber laser and a digital micromirror device (DMD) has been developed to meet demands of spectroradiometric calibrations for ground-based, aeronautics-based, and aerospace-based remote sensing instruments and spectral simulations of natural scenes such as the sun and atmosphere. Using a supercontinuum fiber laser as a radiant source, the spectral radiance of the spectrally tunable radiant source is 20 times higher than the spectrally tunable radiant source using conventional radiant sources such as tungsten halogen lamps, xenon lamps, or LED lamps, and the stability is better than ±0.3%/h. Using a DMD, the spectrally tunable radiant source possesses two working modes. In narrow-band modes, it is calibrated by an absolute detector, and in broad-band modes, it can calibrate for remote sensing instrument. The uncertainty of the spectral radiance of the spectrally tunable radiant source is estimated at less than 1.87% at 350 nm to 0.85% at 750 nm, and compared to only standard lamp-based calibration, a greater improvement is gained.

Spectra of Th/Ar and U/Ne hollow cathode lamps for spectrograph calibration

NASA Astrophysics Data System (ADS)

Nave, Gillian; Shlosberg, Ariel; Kerber, Florian; Den Hartog, Elizabeth; Neureiter, Bianca

2018-01-01

Low-current Th/Ar hollow cathode lamps have long been used for calibration of astronomical spectrographs on ground-based telescopes. Thorium is an attractive element for calibration as it has a single isotope, has narrow spectral lines, and has a dense spectrum covering the whole of the visible region. However, the high density of the spectrum that makes it attractive for calibrating high-resolution spectrographs is a detriment for lower resolution spectrographs and this is not obvious by examination of existing linelists. In addition, recent changes in regulations regarding the handling of thorium have led to a degradation in the quality of Th/Ar calibration lamps, with contamination by molecular ThO lines that are strong enough to obscure the calibration lines of interest.We are pursuing two approaches to these problems. First, we have expanded and improved the NIST Standard Reference Database 161, "Spectrum of Th-Ar Hollow Cathode Lamps" to cover the region 272 nm to 5500 nm. Spectra of hollow cathode lamps at up to 3 different currents can now be displayed simultaneously. Interactive zooming and the ability to convolve any of the spectra with a Gaussian or uploaded instrument profile enable the user to see immediately what the spectrum would look like at the particular resolution of their spectrograph. Second, we have measured the spectrum of a recent, contaminated Th/Ar hollow cathode lamp using a high-resolution Echelle spectrograph (Madison Wisconsin) at a resolving power (R~ 250,000). This significantly exceeds the resolving power of most astronomical spectrographs and resolves many of the molecular lines of ThO. With these spectra we are measuring and calibrating the positions of these molecular lines in order to make them suitable for spectrograph calibration.In the near infrared region, U/Ne hollow cathode lamps give a higher density of calibration lines than Th/Ar lamps and will be implemented on the upgraded CRIRES+ spectrograph on ESO’s Very Large Telescope in Chile. A new atlas of the U/Ne spectrum as measured by CRIRES will be presented.

Development and clinical performance of high throughput loop-mediated isothermal amplification for detection of malaria

PubMed Central

Perera, Rushini S.; Ding, Xavier C.; Tully, Frank; Oliver, James; Bright, Nigel; Bell, David; Chiodini, Peter L.; Gonzalez, Iveth J.; Polley, Spencer D.

2017-01-01

Background Accurate and efficient detection of sub-microscopic malaria infections is crucial for enabling rapid treatment and interruption of transmission. Commercially available malaria LAMP kits have excellent diagnostic performance, though throughput is limited by the need to prepare samples individually. Here, we evaluate the clinical performance of a newly developed high throughput (HTP) sample processing system for use in conjunction with the Eiken malaria LAMP kit. Methods The HTP system utilised dried blood spots (DBS) and liquid whole blood (WB), with parallel sample processing of 94 samples per run. The system was evaluated using 699 samples of known infection status pre-determined by gold standard nested PCR. Results The sensitivity and specificity of WB-HTP-LAMP was 98.6% (95% CI, 95.7–100), and 99.7% (95% CI, 99.2–100); sensitivity of DBS-HTP-LAMP was 97.1% (95% CI, 93.1–100), and specificity 100% against PCR. At parasite densities greater or equal to 2 parasites/μL, WB and DBS HTP-LAMP showed 100% sensitivity and specificity against PCR. At densities less than 2 p/μL, WB-HTP-LAMP sensitivity was 88.9% (95% CI, 77.1–100) and specificity was 99.7% (95% CI, 99.2–100); sensitivity and specificity of DBS-HTP-LAMP was 77.8% (95% CI, 54.3–99.5) and 100% respectively. Conclusions The HTP-LAMP system is a highly sensitive diagnostic test, with the potential to allow large scale population screening in malaria elimination campaigns. PMID:28166235

Loop mediated isothermal amplification (LAMP) assay for detection of coconut root wilt disease and arecanut yellow leaf disease phytoplasma.

PubMed

Nair, Smita; Manimekalai, Ramaswamy; Ganga Raj, Palliyath; Hegde, Vinayaka

2016-07-01

The coconut root wilt disease (RWD) and the arecanut yellow leaf disease (YLD) are two major phytoplasma associated diseases affecting palms in South India. Greatly debilitating the palm health, these diseases cause substantial yield reduction and economic loss to farmers. A rapid and robust diagnostic technique is crucial in efficient disease management. We established phytoplasma 16S rDNA targeted loop mediated isothermal amplification (LAMP) and real time LAMP based diagnostics for coconut RWD and arecanut YLD. The LAMP reaction was set at 65 °C and end point detection made using hydroxynaphthol blue (HNB) and agarose gel electrophoresis. Molecular typing of LAMP products were made with restriction enzyme HpyCH4 V. Conventional PCR with LAMP external primers and sequencing of amplicons was carried out. Real time LAMP was performed on the Genei II platform (Optigene Ltd., UK). An annealing curve analysis was programmed at the end of the incubation to check the fidelity of the amplicons. The phytoplasma positive samples produced typical ladder like bands on agarose gel, showed colour change from violet to blue with HNB and produced unique annealing peak at 85 ± 0.5 °C in the real time detection. Restriction digestion produced predicted size fragments. Sequencing and BLASTN analysis confirmed that the amplification corresponded to phytoplasma 16S rRNA gene. LAMP method devised here was found to be more robust compared to conventional nested PCR and hence has potential applications in detection of phytoplasma from symptomatic palm samples and in rapid screening of healthy seedlings.

Extracellular level of basolateral amygdalar dopamine responding to reversal of appetitive-conditioned discrimination in young and old rats.

PubMed

Nomura, Masahiko; Izaki, Yoshinori; Takita, Masatoshi; Tanaka, Junichi; Hori, Koji

2004-08-27

Young and old rats, aged 3 and 24 months old, respectively, were conditioned to press a lever under lamp-on conditions for reward acquisition and lamp-off for no reward using a variable interval reinforcement schedule that averaged 15 s; i.e., the minimal requirement was 4 responses/min. Over a 30-day period, young and old groups showed increased response to lamp-on from 22 to 35/min and from 10 to 23/min, respectively, and shortened response to lamp-off after initial training. Response to lamp-on as a percentage of total response to lamp-on and -off (the discrimination ratio) was over 80%. For the next 30 days, reversal learning was imposed to reinforce discrimination of the lamp-off state. Young rats showed a steadily increasing discrimination ratio from 40% to 70%, and old rats from 30% to 60%. In comparison with the initial training, young rats showed a total response increase from 50% to 60%, while old rats showed an approximately 5% decrease without loss of reward-obtaining efficiency. In vivo microdialysis during reversal revealed that young rats had higher dopamine transmission in the basolateral amygdala than old rats. The dopamine level was positively correlated with the number of responses to state of reward in young rats and negatively with the numbers of both NRF and RF responses to lamp-on and -off states in old rats. These results suggest that in reversal discrimination, basolateral amygdalar dopamine efflux correlates with the manner of age-related conditioned response rather than the ability to learn.

Keeping Floodlight Temperature Low

NASA Technical Reports Server (NTRS)

Kiss, John

1987-01-01

Safety in explosive atmospheres enhanced. Retainer for floodlight designed to undergo relatively small temperature rise. Reaches no more than 350 degrees F (177 degrees C) with lamp operating at about 4,700 degrees F (2,600 degrees C). Satisfies 352 degrees F (188 degrees C) requirement for operation in some explosive atmospheres. Made of thermally conductive metal with coating of material having low thermal absorptivity/emissivity ratio so it conducts heat away from lamp and radiates to surroundings efficiently.

10 CFR 431.324 - Uniform test method for the measurement of energy efficiency of metal halide ballasts.

Code of Federal Regulations, 2010 CFR

2010-01-01

... efficiency of metal halide ballasts. 431.324 Section 431.324 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Metal Halide Lamp Ballasts and Fixtures Test Procedures § 431.324 Uniform test method for the measurement of energy efficiency of metal...

High-power UV-LED degradation: Continuous and cycled working condition influence

NASA Astrophysics Data System (ADS)

Arques-Orobon, F. J.; Nuñez, N.; Vazquez, M.; Segura-Antunez, C.; González-Posadas, V.

2015-09-01

High-power (HP) UV-LEDs can replace UV lamps for real-time fluoro-sensing applications by allowing portable and autonomous systems. However, HP UV-LEDs are not a mature technology, and there are still open issues regarding their performance evolution over time. This paper presents a reliability study of 3 W UV-LEDs, with special focus on LED degradation for two working conditions: continuous and cycled (30 s ON and 30 s OFF). Accelerated life tests are developed to evaluate the influence of temperature and electrical working conditions in high-power LEDs degradation, being the predominant failure mechanism the degradation of the package. An analysis that includes dynamic thermal and optical HP UV-LED measurements has been performed. Static thermal and stress simulation analysis with the finite element method (FEM) identifies the causes of package degradation. Accelerated life test results prove that HP UV-LEDs working in cycled condition have a better performance than those working in continuous condition.

Enhanced Phycocyanin Production from Spirulina platensis using Light Emitting Diode

NASA Astrophysics Data System (ADS)

Bachchhav, Manisha Bhanudas; Kulkarni, Mohan Vinayak; Ingale, Arun G.

2017-06-01

This work investigates the performance of different cultivation conditions using Light Emitting Diode (LED) as a light source for the production of phycocyanin from Spirulina platensis. With LEDs under autotrophic conditions, red LED produced maximum amount of biomass (8.95 g/l). As compared to autotrophic cultivation with fluorescent lamp (control), cultivations using LEDs under autotrophic and mixotrophic mode significantly enhanced the phycocyanin content. For autotrophic conditions (with LED) phycocyanin content was in the range of 103-242 mg/g of dry biomass, whereas for mixotrophic conditions (0.1% glucose and LED) it was in the range of 254-380 mg/g of dry biomass. Spirulina cultivated with yellow LED under mixotrophic conditions had 5.4-fold more phycocyanin (380 mg/g of dry biomass) than control (70 mg/g of dry biomass). The present study demonstrates that the LEDs under mixotrophic conditions gave sixfold (2497 mg/l) higher yields of phycocyanin as compared to autotrophic condition under white light (415 mg/l).

Microwave discharge electrodeless lamps (MDEL). Part VII. Photo-isomerization of trans-urocanic acid in aqueous media driven by UV light from a novel Hg-free Dewar-like microwave discharge thermally-insulated electrodeless lamp (MDTIEL). Performance evaluation.

PubMed

Horikoshi, Satoshi; Sato, Tatsuro; Sakamoto, Kazutami; Abe, Masahiko; Serpone, Nick

2011-07-01

A novel mercury-free Dewar-like (double-walled structure) microwave discharge thermally-insulated electrodeless lamp (MDTIEL) was fabricated and its performance evaluated using the photo-isomerization of trans-urocanic acid (trans-UA) in aqueous media as a test process driven by the emitted UV light when ignited with microwave radiation. The photo-isomerization processes trans-UA → cis-UA and cis-UA → trans-UA were re-visited using light emitted from a conventional high-pressure Hg light source and examined for the influence of UV light irradiance and solution temperature; the temperature dependence of the trans → cis process displayed a negative activation energy, E(a) = -1.3 cal mol(-1). To control the photo-isomerization of urocanic acid from the heat usually dissipated by a microwave discharge electrodeless lamp (single-walled MDEL), it was necessary to suppress the microwave-initiated heat. For comparison, the gas-fill in the MDEL lamp, which typically consists of a mixture of Hg and Ar, was changed to the more eco-friendly N(2) gas in the novel MDTIEL device. The dynamics of the photo-isomerization of urocanic acid driven by the UV wavelengths of the N(2)-MDTIEL light source were compared to those from the more conventional single-walled N(2)-MDEL and Hg/Ar-MDEL light sources, and with those from the Hg lamp used to irradiate, via a fiber optic, the photoreactor located in the wave-guide of the microwave apparatus. The heating efficiency of a solution with the double-walled N(2)-MDTIEL was compared to the efficiency from the single-walled N(2)-MDEL device. Advantages of N(2)-MDTIEL are described from a comparison of the dynamics of the trans-UA → cis-UA process on the basis of unit surface area of the lamp and unit power consumption. The considerably lower temperature on the external surface of the N(2)-MDTIEL light source should make it attractive in carrying out photochemical reactions that may be heat-sensitive such as the photothermochromic urocanic acid system.