scholarly journals Analysis of LLL System Properties for Different Excitation Parameters

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7723
Author(s):  
Krzysztof Wandachowicz ◽  
Małgorzata Zalesińska ◽  
Przemysław Otomański
Keyword(s):  
Light Sources ◽  
Primary Method ◽  
Escape Route ◽  
Fluorescent Lamps ◽  
Interior Lighting ◽  
Passenger Ships ◽  
System Properties ◽  
Materials Used ◽  
Photoluminescent Materials ◽  
Excitation Parameters

Photoluminescent strips forming a Low Location Lighting (LLL) system are the primary method for marking escape routes on passenger ships. The LLL system can be built as a self-luminous system (powered by electricity) or made as a series of strips made of photoluminescent materials, which glow and indicate the escape route after the loss of basic and emergency lighting. To ensure correct visual guidance, these strips must be installed at specific locations in the passageways and achieve appropriate photometric parameters after a certain time from their activation. The properties of the LLL system depend on the type of luminescent material used, the excitation source, and the exposure parameters. This paper presents the results of laboratory tests on two types of photoluminescent materials used for the construction of LLL systems. We recorded the change in luminance after the loss of excitation and measured the luminance values obtained 10 and 60 min after the loss of excitation under exposure to light sources commonly used for interior lighting on passenger ships. It turns out that replacing fluorescent lamps with LED lamps can reduce the luminance of the LLL system.

scholarly journals An Introduction to Light-emitting Diodes

HortScience ◽  
2008 ◽  
Vol 43 (7) ◽  
pp. 1944-1946 ◽  
Author(s):  
C. Michael Bourget
Keyword(s):  
Light Emitting Diodes ◽  
Arc Discharge ◽  
Visible Spectrum ◽  
Constant Current ◽  
Light Sources ◽  
Total System ◽  
Light Emitting ◽  
Fluorescent Lamps ◽  
Materials Used ◽  
Incandescent Lamps

Light-emitting diodes (LEDs) are semiconductor devices that produce noncoherent, narrow-spectrum light when forward voltage is applied. LEDs range in wavelength from the UVC band to infrared (IR) and are available in packages ranging from milliwatts to more than 10 W. The first LED was an IR-emitting device and was patented in 1961. In 1962, the first practical visible spectrum LED was developed. The first high-power (1-W) LEDs were developed in the late 1990s. LEDs create light through a semiconductor process rather than with a superheated element, ionized gas, or an arc discharge as in traditional light sources. The wavelength of the light emitted is determined by the materials used to form the semiconductor junction. LEDs produce more light per electrical watt than incandescent lamps with the latest devices rivaling fluorescent tubes in energy efficiency. They are solid-state devices, which are much more robust than any glass-envelope lamp and contain no hazardous materials like fluorescent lamps. LEDs also have a much longer lifetime than incandescent, fluorescent, and high-density discharge lamps (U.S. Dept. of Energy). Although LEDs possess many advantages over traditional light sources, a total system approach must be considered when designing an LED-based lighting system. LEDs do not radiate heat directly, but do produce heat that must be removed to ensure maximum performance and lifetime. LEDs require a constant-current DC power source rather than a standard AC line voltage. Finally, because LEDs are directional light sources, external optics may be necessary to produce the desired light distribution. A properly designed LED light system is capable of providing performance and a lifetime well beyond any traditional lighting source.

scholarly journals AgNO3 improved micropropagation and stimulate in vitro flowering of rose (Rosa x hybrida) cv. Sena

2021 ◽  
Vol 27 (1) ◽  
pp. 33-40
Author(s):  
Ana Victória Conde da Silva de Matos ◽  
Bárbara Samantha de Oliveira ◽  
Maria Eduarda Barboza Souza de Oliveira ◽  
Jean Carlos Cardoso
Keyword(s):  
In Vitro Flowering ◽  
Light Sources ◽  
Multiplication Rate ◽  
Cut Flower ◽  
Physiological Disorders ◽  
Fluorescent Lamps ◽  
The Rose ◽  
Disease Free ◽  
Early Leaf Senescence

Abstract Rose is one of the most important cut flower in the world. Rose micropropagation was used for production of clonal and disease-free plantlets and to breeding purposes. However, many important rose cultivars showed physiological disorders as early-leaf senescence and very low multiplication rate under in vitro conditions. Our hypothesis is that these symptoms were associated with high sensibility of these cultivars to ethylene accumulation on in vitro environment. The rose cv. Sena was in vitro cultivated under different concentrations of AgNO3 and two light sources, LED and fluorescent lamps, as a way to investigate in vitro similar symptoms to ethylene accumulation. AgNO3 at 1.0-2.0 mg L-1 solved the main in vitro physiological disorders observed in this rose cultivar. Also, AgNO3 stimulated induction of 50% of rose shoots to in vitro flowering at 2.0 mg L-1. Higher concentrations also resulted in flowering induction, but with imperfect flower development.

ENERGY EFFICIENT LIGHTING OF PUBLIC PREMISES

2021 ◽  
pp. 54-56
Author(s):  
E. A. Kuznetsov ◽  
N. P. Nesterkina ◽  
Yu. A. Zhuravleva ◽  
S. A. Mikaeva
Keyword(s):  
Educational Institution ◽  
Light Output ◽  
Light Flux ◽  
High Energy ◽  
Educational Institutions ◽  
Energy Costs ◽  
Light Sources ◽  
Fluorescent Lamps ◽  
High Level ◽  
Incandescent Lamps

The article provides a technical and economic comparison of costs when covering 10 classrooms of a general educational institution with LED and fluorescent lamps for a period of 10 years. The main advantage of led light sources is the high level of light output compared to traditional light sources. Replacing incandescent lamps and gas-discharge ICS with led ICS can significantly reduce energy costs. Currently, led ICS are increasingly replacing traditional ICS due to their high energy efficiency and safety. For comparison, luminescent lamps LVO04-4x14-031 and LED lamps DVO12-45-003 produced by JSC “Ardatovsky lighting plant” with a comparable light flux and light distribution were selected. The number of lamps in the 65 m2 auditorium was chosen based on the normalized illumination of 500 Lux on a horizontal work surface (0.8 m). The calculation of the number of lamps that meet all the requirements for lighting in General and higher educational institutions was carried out in the DiaLux 4.13 program. According to preliminary calculations, lighting with led lamps will reduce energy costs over 10 years by 2.16 times compared to fluorescent lamps. The maximum expenses are spent on the purchase of new led lamps. This is mainly due to the higher price of led lighting devices compared to fluorescent ones.

scholarly journals Effects of Different Colored LEDs on the Enhancement of Biologically Active Ingredients in Callus Cultures of Gynura procumbens (Lour.) Merr.

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4336 ◽  
Author(s):  
Thang Tung Lian ◽  
Se-Yeoun Cha ◽  
Myat Myat Moe ◽  
Yong Ju Kim ◽  
Keuk Soo Bang
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Leaf Explants ◽  
Callus Cultures ◽  
Biologically Active ◽  
Naphthaleneacetic Acid ◽  
Light Sources ◽  
Light Emitting ◽  
Fluorescent Lamps ◽  
Wavelength Emission

Conventional fluorescent lamps that are used in tissue culture are costly light sources, exhibiting excessive wavelength emission-bandwidth that must be replaced by alternative, less costly, and much lower power-consuming energy sources. The use of Light-Emitting Diodes (LEDs) is the best option due to their potential role as elicitors of secondary metabolite production in many plant models. Gynura procumbens (G. procumbens) is widely used for treating various diseases. Here, leaf explants were cultivated in MS medium that was supplemented with 0.5 mg/L of naphthaleneacetic acid (NAA) and 2.0 mg/L of benzylaminopurine (BAP) for 30 days under white, blue, and red LEDs. Secondary metabolites were analyzed by High Performance Liquid Chromatography (HPLC) and Liquid Chromatography-Mass Spectrometry (LC-MS). Blue LEDs elicited the highest antioxidant activity, total flavonoid, and phenolic content. Furthermore, the content of cyanidin-monoglucosides significantly increased under blue light.

Evaluation Index Study of Students’ Physiological Rhythm Effects under Fluorescent Lamp and LED

2012 ◽  
Vol 433-440 ◽  
pp. 4757-4764 ◽  
Author(s):  
Yong Hong Yan ◽  
Tang G. Lee ◽  
Yang Guan ◽  
Xiang De Liu
Keyword(s):  
Luminance Level ◽  
Evaluation Index ◽  
Light Sources ◽  
Fluorescent Lamp ◽  
Colour Temperature ◽  
Learning Efficiency ◽  
Fluorescent Lamps ◽  
Comprehensive Index ◽  
Index Study ◽  
Typical Colour

The influence of artificial classroom light source’s colour temperature to students’ learning efficiency and physiology rhythm is the focus of this study. An experiment compares a subjects’ learning efficiency, asthenopia and brain fag under different luminance level of three typical colour temperatures from T5 fluorescent lamps and LED. Using comprehensive index ε and norm identification Ψ for quantitative evaluation and testing under different lighting environments, we determined the best colour temperature of two experimental light sources. We also determined the best combinations of illuminance value and the colour temperature that should be avoided in classroom lighting. Experiment shows that spectrum difference obviously effects comprehensive index ε and norm identification Ψ. For learning efficiency and health of people, there need to be improvement in the spectrum of fluorescent lamps and LEDs

Laying hens do not have a preference for high-frequency versus low-frequency compact fluorescent light sources

1996 ◽  
Vol 76 (2) ◽  
pp. 177-181 ◽  
Author(s):  
T. M. Widowski ◽  
I.J.H. Duncan
Keyword(s):  
High Frequency ◽  
Laying Hens ◽  
Low Frequency ◽  
Fluorescent Light ◽  
Feed Water ◽  
Light Sources ◽  
Frequency Distributions ◽  
Video Cameras ◽  
Fluorescent Lamps ◽  
Testing Chamber

To determine whether hens find the flicker of some fluorescent light aversive, the preferences of 16 light hybrid laying hens for light produced by high-frequency or low-frequency compact fluorescent lamps were tested individually in a two-room testing chamber in which each room could be illuminated by either source. The spectral distributions of the lamps and levels of illumination (ca. 14 lx) in the two rooms were carefully matched and both rooms contained feed, water, and a nesting area. Overhead video cameras recorded the position and behaviour of the birds during a 6-h test period on each of 2 d. The light sources in the rooms were switched on the second test day to balance for any preferences for chamber room.On both test days, the birds spent similar amounts of time in fluorescent light produced by high-frequency and low-frequency lamps (P > 0.10). When data from both test days were combined, the birds spent on average 48.2% of time in light from high-frequency lamps and 51.8% from low-frequency. The frequency distributions of individual activities indicated that the birds performed all activities in light produced by both types of lamps. The results indicate that the laying hens in this experiment did not exhibit a preference for high-frequency fluorescent lamps over low-frequency lamps. We conclude that at the illumination levels used in this experiment, the hens did not perceive the flicker of low-frequency light or they perceived it but did not find it aversive. Low-frequency fluorescent light does not appear to adversely affect the welfare of hens. Key words: Lighting, fluorescent, flicker, behaviour, poultry

scholarly journals A Method to Realize Efficient Deep-Red Phosphorescent OLEDs with a Broad Spectral Profile and Low Operating Voltages

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5723
Author(s):  
Wei-Ling Chen ◽  
Shan-Yu Chen ◽  
Dun-Cheng Huang ◽  
Dian Luo ◽  
Hsueh-Wen Chen ◽  
...  
Keyword(s):  
Carrier Transport ◽  
Layer Structure ◽  
Hole Injection ◽  
Electroluminescence Spectrum ◽  
Light Sources ◽  
Spectral Profile ◽  
Coverage Ratio ◽  
Design Concepts ◽  
Red Phosphors ◽  
Materials Used

Organic light-emitting diodes (OLEDs) used as phototherapy light sources require sufficient spectral distribution in the effective wavelength ranges and low operating voltages. Herein, a double emitting layer structure consisting of a red-emitting Ir(piq)2acac and a deep-red Ir(fliq)2acac was designed to generate a broad electroluminescence spectrum. An efficient TCTA:CN-T2T exciplex system was used as the host of the emitting layer, facilitating effective energy transfer from the exciplex host to the red and deep-red phosphors. The materials used in the exciplex host were also used as the carrier transport layers to eliminate the energy barriers and thus increase the current density. The hole injection layer structures were varied to examine the hole injection capabilities and the carrier balance. The resulting optimized phosphorescent OLEDs with a broad spectral profile exhibit a 90% coverage ratio in the target ranges from 630 to 690 nm, together with a high peak efficiency of 19.1% (10.2 cd/A and 13.8 lm/W). The proposed device only needs 5.2 V to achieve a power density of 5 mW/cm2, implying that the device could be driven via two series-connected button cell batteries. These results illustrate the feasibility of our design concepts and demonstrate the realization of a portable and lightweight OLED phototherapy light source.

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