Related Research Articles
Light pollution is the presence of any unwanted, inappropriate, or excessive artificial lighting. In a descriptive sense, the term light pollution refers to the effects of any poorly implemented lighting sources, during the day or night. Light pollution can be understood not only as a phenomenon resulting from a specific source or kind of pollution, but also as a contributor to the wider, collective impact of various sources of pollution.
A halogen lamp is an incandescent lamp consisting of a tungsten filament sealed in a compact transparent envelope that is filled with a mixture of an inert gas and a small amount of a halogen, such as iodine or bromine. The combination of the halogen gas and the tungsten filament produces a halogen-cycle chemical reaction, which redeposits evaporated tungsten on the filament, increasing its life and maintaining the clarity of the envelope. This allows the filament to operate at a higher temperature than a standard incandescent lamp of similar power and operating life; this also produces light with higher luminous efficacy and color temperature. The small size of halogen lamps permits their use in compact optical systems for projectors and illumination. The small glass envelope may be enclosed in a much larger outer glass bulb, which has a lower temperature, protects the inner bulb from contamination, and makes the bulb mechanically more similar to a conventional lamp.
Lighting or illumination is the deliberate use of light to achieve practical or aesthetic effects. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing daylight. Daylighting is sometimes used as the main source of light during daytime in buildings. This can save energy in place of using artificial lighting, which represents a major component of energy consumption in buildings. Proper lighting can enhance task performance, improve the appearance of an area, or have positive psychological effects on occupants.
A sodium-vapor lamp is a gas-discharge lamp that uses sodium in an excited state to produce light at a characteristic wavelength near 589 nm.
High-intensity discharge lamps are a type of electrical gas-discharge lamp which produces light by means of an electric arc between tungsten electrodes housed inside a translucent or transparent fused quartz or fused alumina arc tube. This tube is filled with noble gas and often also contains suitable metal or metal salts. The noble gas enables the arc's initial strike. Once the arc is started, it heats and evaporates the metallic admixture. Its presence in the arc plasma greatly increases the intensity of visible light produced by the arc for a given power input, as the metals have many emission spectral lines in the visible part of the spectrum. High-intensity discharge lamps are a type of arc lamp.
The history of street lighting in the United States is closely linked to the urbanization of America. Artificial illumination has stimulated commercial activity at night, and has been tied to the country's economic development, including major innovations in transportation, particularly the growth in automobile use. In the two and a half centuries before LED lighting emerged as the new "gold standard", cities and towns across America relied on oil, coal gas, carbon arc, incandescent, and high-intensity gas discharge lamps for street lighting.
A metal-halide lamp is an electrical lamp that produces light by an electric arc through a gaseous mixture of vaporized mercury and metal halides. It is a type of high-intensity discharge (HID) gas discharge lamp. Developed in the 1960s, they are similar to mercury vapor lamps, but contain additional metal halide compounds in the quartz arc tube, which improve the efficiency and color rendition of the light. The most common metal halide compound used is sodium iodide. Once the arc tube reaches its running temperature, the sodium dissociates from the iodine, adding orange and reds to the lamp's spectrum from the sodium D line as the metal ionizes. As a result, metal-halide lamps have high luminous efficacy of around 75–100 lumens per watt, which is about twice that of mercury vapor lights and 3 to 5 times that of incandescent lights and produce an intense white light. Lamp life is 6,000 to 15,000 hours. As one of the most efficient sources of high CRI white light, metal halides as of 2005 were the fastest growing segment of the lighting industry. They are used for wide area overhead lighting of commercial, industrial, and public places, such as parking lots, sports arenas, factories, and retail stores, as well as residential security lighting, automotive headlamps and indoor cannabis grow operations.
The induction lamp, electrodeless lamp, or electrodeless induction lamp is a gas-discharge lamp in which an electric or magnetic field transfers the power required to generate light from outside the lamp envelope to the gas inside. This is in contrast to a typical gas discharge lamp that uses internal electrodes connected to the power supply by conductors that pass through the lamp envelope. Eliminating the internal electrodes provides two advantages:
A ceramic metal-halide lamp (CMH), also generically known as a ceramic discharge metal-halide (CDM) lamp, is a type of metal-halide lamp that is 10–20% more efficient than the traditional quartz metal halide and produces a superior color rendition.
A parabolic aluminized reflector lamp is a type of electric lamp that is widely used in commercial, residential, and transportation illumination. It produces a highly directional beam. Usage includes theatrical lighting, locomotive headlamps, aircraft landing lights, and residential and commercial recessed lights.
A grow light is an electric light that can help plants grow. Grow lights either attempt to provide a light spectrum similar to that of the sun, or to provide a spectrum that is more tailored to the needs of the plants being cultivated. Outdoor conditions are mimicked with varying colour temperatures and spectral outputs from the grow light, as well as varying the intensity of the lamps. Depending on the type of plant being cultivated, the stage of cultivation, and the photoperiod required by the plants, specific ranges of spectrum, luminous efficacy and color temperature are desirable for use with specific plants and time periods.
An LED lamp or LED light is an electric light that produces light using light-emitting diodes (LEDs). LED lamps are significantly more energy-efficient than equivalent incandescent lamps and fluorescent lamps. The most efficient commercially available LED lamps have efficiencies exceeding 200 lumens per watt (lm/W) and convert more than half the input power into light. Commercial LED lamps have a lifespan several times longer than both incandescent and fluorescent lamps.
Aquarium lighting describes any type of artificial lighting that is used to illuminate an aquarium. Some types of aquaria such as reef aquariums and planted aquariums require specialized high intensity lighting to support photosynthetic life within the tank.
Often task lighting refers to increasing illuminance to better accomplish a specific activity. However, the illuminance level is not the only factor governing visibility. Contrast is also important, and a poorly positioned light source may cause contrast reduction, resulting in loss of visibility. The most important purpose of task lighting in the office is not increasing illuminance, but improving contrast. General lighting can be reduced because task lighting provides focused light where needed.
Vari-Lite is a brand of automated, variable-colour stage lighting systems. Their intelligent lighting fixtures are commonly used in theatre, concerts, television, film and corporate events.
An LED street light or road light is an integrated light-emitting diode (LED) light fixture that is used for street lighting.
Plasma lamps are a type of electrodeless gas-discharge lamp energized by radio frequency (RF) power. They are distinct from the novelty plasma lamps that were popular in the 1980s.
The L-Prize competition was designed to spur development of LED light replacements for 60W incandescent lamps and PAR38 halogen lamps as well as an ultra-efficient "21st Century Lamp". It was established by the United States Department of Energy (DOE) as directed by the Energy Independence and Security Act of 2007. The original competition, launched in 2008, focused on an LED replacement for the common 60-watt light bulb and this L-Prize was awarded in 2011. The PAR38 competition was launched but received no entries and was suspended in 2014. The 21st Century Lamp competition was never opened.
Sylvania Lighting, Havells-Sylvania, and SLI, is an international designer and manufacturer of lighting products, trading as Sylvania. It has plants throughout Europe, Asia, North Africa and Central and South America, and is one of the few lighting companies that produces both lamps and lighting fixtures. It is owned by Shanghai Feilo Acoustics Ltd., having previously been owned by the Indian electrical company Havells.
Solar street lights are raised light sources which are powered by solar panels generally mounted on the lighting structure or integrated into the pole itself. The solar panels charge a rechargeable battery, which powers a fluorescent or LED lamp during the night.
References
- ↑ "Hubbell Lighting" (brochure). Hubbell Lighting. 2009. p. 3. Retrieved 2009-10-20.[ dead link ]
- ↑ "Pulse-Start Metal Halide Lighting". Natural Resources Canada. 2009. Archived from the original on 2009-04-17. Retrieved 2009-10-20.
