scholarly journals LED Lighting in Horticulture

HortScience ◽  
2008 ◽  
Vol 43 (7) ◽  
pp. 1947-1950 ◽  
Author(s):  
Robert C. Morrow
Keyword(s):  
Solid State ◽  
Large Scale ◽  
Space Shuttle ◽  
Space Station ◽  
Spectral Composition ◽  
Light Output ◽  
Plant Morphology ◽  
Heat Output ◽  
Led Lighting ◽  
Lighting Systems

Solid-state lighting based on the use of light-emitting diodes (LEDs) is potentially one of the biggest advancements in horticultural lighting in decades. LEDs can play a variety of roles in horticultural lighting, including use in controlled environment research, lighting for tissue culture, and supplemental and photoperiod lighting for greenhouses. LED lighting systems have several unique advantages over existing horticultural lighting, including the ability to control spectral composition, the ability to produce very high light levels with low radiant heat output when cooled properly, and the ability to maintain useful light output for years without replacement. LEDs are the first light source to have the capability of true spectral composition control, allowing wavelengths to be matched to plant photoreceptors to provide more optimal production and to influence plant morphology and composition. Because they are solid-state devices, LEDs are easily integrated into digital control systems, facilitating special lighting programs such as “daily light integral” lighting and sunrise and sunset simulations. LEDs are safer to operate than current lamps because they do not have glass envelopes or high touch temperatures, and they do not contain mercury. The first sustained work with LEDs as a source of plant lighting occurred in the mid-1980s to support the development of new lighting systems to be used in plant growth systems designed for research on the space shuttle and space station. These systems progressed from simple red-only LED arrays using the limited components available at the time to high-density, multicolor LED chip-on-board devices. As light output increases while device costs decrease, LEDs continue to move toward becoming economically feasible for even large-scale horticultural lighting applications.

scholarly journals LED Lighting Systems for Horticulture: Business Growth and Global Distribution

2020 ◽  
Vol 12 (18) ◽  
pp. 7516 ◽  
Author(s):  
Ivan Paucek ◽  
Elisa Appolloni ◽  
Giuseppina Pennisi ◽  
Stefania Quaini ◽  
Giorgio Gianquinto ◽  
...  
Keyword(s):  
Plant Growth ◽  
Light Output ◽  
Working Hours ◽  
Light Emitting ◽  
Led Lighting ◽  
Plant Cultivation ◽  
The Status ◽  
Fast Development ◽  
Lighting Systems ◽  
Main Component

In recent years, research on light emitting diodes (LEDs) has highlighted their great potential as a lighting system for plant growth, development and metabolism control. The suitability of LED devices for plant cultivation has turned the technology into a main component in controlled or closed plant-growing environments, experiencing an extremely fast development of horticulture LED metrics. In this context, the present study aims to provide an insight into the current global horticulture LED industry and the present features and potentialities for LEDs’ applications. An updated review of this industry has been integrated through a database compilation of 301 manufacturers and 1473 LED lighting systems for plant growth. The research identifies Europe (40%) and North America (29%) as the main regions for production. Additionally, the current LED luminaires’ lifespans show 10 and 30% losses of light output after 45,000 and 60,000 working hours on average, respectively, while the vast majority of worldwide LED lighting systems present efficacy values ranging from 2 to 3 μmol J−1 (70%). Thus, an update on the status of the horticultural LED sector, LEDs’ applications and metrics, and the intense innovation are described and discussed.

In the Eyes of the World: The Signaling Value of Space Exploration

2017 ◽  
Author(s):  
Alexander MacDonald
Keyword(s):  
Private Sector ◽  
Large Scale ◽  
Space Shuttle ◽  
Space Exploration ◽  
Space Station ◽  
The Political ◽  
Individual Level ◽  
Space Race ◽  
History Of ◽  
The Cold War

The chapter explores the political and economic origins of the Cold War Space Race. Unlike the earlier private-sector led phases of space exploration, it was the large-scale political demand for spaceflight that provided a new driving economic force starting in the late 1950s. It is the political history of this period that has dominated the history of spaceflight and has given it an overwhelming governmental and public-sector focus, relegating the earlier history of private-sector support to the footnotes and sidelines. The driving motivation during this period for the provision of public funds was a desire to signal status and capability through monumental achievement—this time at a national scale rather than at the city or individual level at which earlier space exploration projects, such as astronomical observatories, had been focused. Understanding space exploration as a signaling function for the nation and the nation’s leaders provides a perspective that allows pursuits such as the Space Shuttle, Space Station Freedom, and the International Space Station to be understood as resulting from the same exchange mechanism that produced America’s desire to go to the Moon.

Rational Basis for Light Emitting Diode Street Lighting Retrofit Luminaire Selection

2021 ◽  
pp. 036119812110038
Author(s):  
Jennifer A. Brons ◽  
John D. Bullough ◽  
Daniel C. Frering
Keyword(s):  
Light Emitting Diode ◽  
Light Output ◽  
Limited Range ◽  
Street Lighting ◽  
Light Emitting ◽  
Led Lighting ◽  
The Road ◽  
Lighting Systems ◽  
On The Road ◽  
Lighting Retrofit

Many municipalities are beginning to undertake efforts to retrofit their existing high pressure sodium (HPS) street lighting with LED (light emitting diode) luminaires. Unlike HPS lighting systems, which are available in a limited range of standard wattages and configurations, LED street lighting systems vary widely in wattage and physical configuration. Moreover, the technological performance of LED lighting continues to improve, whereas HPS is a mature technology with substantial improvements unlikely in the future. To develop a sound basis for selecting LED lighting systems for retrofit street lighting, photometric simulation calculations under a range of pole spacing, road width and luminaire wattage were performed. The results indicated that LED luminaires can have substantially lower wattage than HPS luminaires to produce the same light levels on the road. Further, LED luminaires tend to direct more of their output onto the road compared with HPS luminaires. As a result, LED luminaires can be used that produce substantially fewer lumens overall than HPS systems. Because the white light from LED sources makes illuminated street scenes appear brighter than the yellowish light from HPS lamps, even further reductions in light output can be accomplished with LED street lighting systems to match the same visual effect under HPS.

Luminous Environment and the Perceived Environment

2019 ◽  
pp. 15-21
Author(s):  
Banu Manav
Keyword(s):  
Experimental Studies ◽  
Light Output ◽  
Lighting Design ◽  
Lighting System ◽  
Main Concept ◽  
Healthy Environment ◽  
Perceived Environment ◽  
Efficiency Cost ◽  
Lighting Systems ◽  
User Friendly

In lighting design, the main concept is to achieve a healthy environment, which addresses energy efficiency, cost, maintenance, and quality. User-friendly lighting systems shall be adopted to architecture and interior architecture. User control over the lighting system is important, by dimming or increasing light output, by changing the colour of the light sets the inner atmosphere and affects user mood. Standards and codes on lighting shall also be evaluated by means of these topics. The paper aims to analyse how the luminous environment is affective on the perceived environment. Hence, a series of experimental studies and recent research will be evaluated in regard to understanding and designing luminous environment.

Iron oxide pigments

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gerhard Pfaff
Keyword(s):  
Iron Oxide ◽  
Solid State ◽  
Large Scale ◽  
Construction Materials ◽  
High Importance ◽  
Precipitation Processes ◽  
Iron Oxide Pigments ◽  
Natural And Synthetic

AbstractNatural and synthetic iron oxide pigments are by far the most important colored pigments. Their high importance is based on the variety of stable colors ranging from yellow via orange, red and brown to black. Iron oxide yellow (α-FeOOH), iron oxide red (α-Fe2O3) and iron oxide black (Fe3O4) are the most important representatives of the iron oxide pigments. Synthetic iron oxide pigments are produced industrially on a large scale by solid-state processes, precipitation processes and by the Laux process. Main advantages of synthetic iron oxide pigments compared with natural types are their pure hue, the consistent, reproducible quality and their tinting strength. Iron oxide pigments are mainly used in construction materials, paints, coatings, and plastics, but also in cosmetics, pharmaceuticals and special applications such as ceramics, magnetic coatings and toners.

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