ASVAB Score Requirements for the Army
Well-designed lighting sends light only where it is needed without scattering it elsewhere. Not to be confused with LCD. Besides the cooking area, the layout of the kitchen must include the storage areas such as shelving and cabinets , preparation area, dishwashing area, receiving area, and garbage disposal area. The further away you move the light from what you want to illuminate, the less bright the light seems! Color space Color model additive subtractive Color mixing Primary color Secondary color Tertiary color intermediate Quaternary color Quinary color Aggressive color warm Receding color cool Pastel colors Color gradient.
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You can get pretty much anywhere in The Mile High City by rail or bus, and often get there faster than by car. If you're craving the personal touch, however, you can call the RTD Customer Care line at Just tell the experts there where you want to catch the bus, where you want to go and when you want to get there.
They'll help you plan your trip including your return home , complete with route numbers, fares and answers to any questions you might have. Customer Care is open weekdays from 6 a. The 16th Street MallRide is a free shuttle that's easy to hop on and off while exploring downtown. Head to your stop! All bus stops have red and white signs that list each bus route that stops at that location, so double check for your route number.
Take note — there's a good chance that your return bus stop is located right across the street. As the bus approaches, check the electronic sign above the windshield to make sure this is indeed the bus you want. Wait for the bus to come to a full stop. The doors will open and you can hop on! If you need to change buses to get to your final destination, ask the driver for a transfer slip, which will get you on your next bus. RTD offers a variety of pass programs, saving you money off regular cash fares.
By purchasing passes or ticket books in advance, you won't have to worry about having exact change every time you ride the bus.
Prehistoric people used primitive oil lamps to illuminate surroundings. These lamps were made from naturally occurring materials such as rocks, shells, horns and stones, were filled with grease , and had a fiber wick.
Lamps typically used animal or vegetable fats as fuel. Hundreds of these lamps hollow worked stones have been found in the Lascaux caves in modern-day France , dating to about 15, years ago. Oily animals birds and fish were also used as lamps after being threaded with a wick. Fireflies have been used as lighting sources. Candles and glass and pottery lamps were also invented. A major reduction in the cost of lighting occurred with the discovery of whale oil.
Gas lighting was economical enough to power street lights in major cities starting in the early s, and was also used in some commercial buildings and in the homes of wealthy people. The gas mantle boosted the luminosity of utility lighting and of kerosene lanterns. The next major drop in price came about in the s with the introduction of electric lighting in the form of arc lights for large space and street lighting followed on by incandescent light bulb based utilities for indoor and outdoor lighting.
Over time, electric lighting became ubiquitous in developed countries. Lighting fixtures come in a wide variety of styles for various functions. The most important functions are as a holder for the light source, to provide directed light and to avoid visual glare. Some are very plain and functional, while some are pieces of art in themselves. Nearly any material can be used, so long as it can tolerate the excess heat and is in keeping with safety codes.
An important property of light fixtures is the luminous efficacy or wall-plug efficiency , meaning the amount of usable light emanating from the fixture per used energy, usually measured in lumen per watt.
A fixture using replaceable light sources can also have its efficiency quoted as the percentage of light passed from the "bulb" to the surroundings. The more transparent the lighting fixture is, the higher efficacy. Shading the light will normally decrease efficacy but increase the directionality and the visual comfort probability. Color temperature for white light sources also affects their use for certain applications.
The color temperature of a white light source is the temperature in kelvins of a theoretical black body emitter that most closely matches the spectral characteristics of the lamp. An incandescent bulb has a color temperature around to kelvins; daylight is around kelvins.
Lower color temperature lamps have relatively more energy in the yellow and red part of the visible spectrum, while high color temperatures correspond to lamps with more of a blue-white appearance. For critical inspection or color matching tasks, or for retail displays of food and clothing, the color temperature of the lamps will be selected for the best overall lighting effect.
Lighting is classified by intended use as general, accent, or task lighting, depending largely on the distribution of the light produced by the fixture. Forms of lighting include alcove lighting, which like most other uplighting is indirect.
This is often done with fluorescent lighting first available at the World's Fair or rope light , occasionally with neon lighting , and recently with LED strip lighting. It is a form of backlighting. Soffit or close to wall lighting can be general or a decorative wall-wash, sometimes used to bring out texture like stucco or plaster on a wall, though this may also show its defects as well.
The effect depends heavily on the exact type of lighting source used. Recessed lighting often called "pot lights" in Canada , "can lights" or 'high hats" in the US is popular, with fixtures mounted into the ceiling structure so as to appear flush with it.
These downlights can use narrow beam spotlights, or wider- angle floodlights , both of which are bulbs having their own reflectors. There are also downlights with internal reflectors designed to accept common 'A' lamps light bulbs which are generally less costly than reflector lamps. Track lighting , invented by Lightolier ,  was popular at one period of time because it was much easier to install than recessed lighting, and individual fixtures are decorative and can be easily aimed at a wall.
It has regained some popularity recently in low-voltage tracks, which often look nothing like their predecessors because they do not have the safety issues that line-voltage systems have, and are therefore less bulky and more ornamental in themselves. A master transformer feeds all of the fixtures on the track or rod with 12 or 24 volts, instead of each light fixture having its own line-to-low voltage transformer.
There are traditional spots and floods, as well as other small hanging fixtures. A modified version of this is cable lighting , where lights are hung from or clipped to bare metal cables under tension. A sconce is a wall-mounted fixture, particularly one that shines up and sometimes down as well.
A torchère is an uplight intended for ambient lighting. It is typically a floor lamp but may be wall-mounted like a sconce. Further interior light fixtures include chandeliers, pendant lights, ceiling fans with lights, close-to-ceiling or flush lights, and various types of lamps . The portable or table lamp is probably the most common fixture, found in many homes and offices.
The standard lamp and shade that sits on a table is general lighting, while the desk lamp is considered task lighting. Magnifier lamps are also task lighting. The illuminated ceiling was once popular in the s and s but fell out of favor after the s. This uses diffuser panels hung like a suspended ceiling below fluorescent lights, and is considered general lighting.
Other forms include neon, which is not usually intended to illuminate anything else, but to actually be an artwork in itself. This would probably fall under accent lighting, though in a dark nightclub it could be considered general lighting. In a movie theater , steps in the aisles are usually marked with a row of small lights for convenience and safety, when the film has started and the other lights are off. Traditionally made up of small low wattage, low voltage lamps in a track or translucent tube, these are rapidly being replaced with LED based versions.
Street Lights are used to light roadways and walkways at night. Some manufacturers are designing LED and photovoltaic luminaires to provide an energy-efficient alternative to traditional street light fixtures. Floodlights can be used to illuminate work zones  or outdoor playing fields during nighttime hours. Beacon lights are positioned at the intersection of two roads to aid in navigation. Sometimes security lighting can be used along roadways in urban areas, or behind homes or commercial facilities.
These are extremely bright lights used to deter crime. Security lights may include floodlights. Entry lights can be used outside to illuminate and signal the entrance to a property. Vehicles typically include headlamps and tail lights. Headlamps are white or selective yellow lights placed in the front of the vehicle, designed to illuminate the upcoming road and to make the vehicle more visible.
Many manufactures are turning to LED headlights as an energy-efficient alternative to traditional headlamps. White rear-facing reversing lamps indicate that the vehicle's transmission has been placed in the reverse gear, warning anyone behind the vehicle that it is moving backwards, or about to do so.
Flashing turn signals on the front, side, and rear of the vehicle indicate an intended change of position or direction. In the late s, some automakers began to use electroluminescent technology to backlight their cars' speedometers and other gauges or to draw attention to logos or other decorative elements. Commonly called 'light bulbs', lamps are the removable and replaceable part of a light fixture, which converts electrical energy into electromagnetic radiation.
While lamps have traditionally been rated and marketed primarily in terms of their power consumption, expressed in watts , proliferation of lighting technology beyond the incandescent light bulb has eliminated the correspondence of wattage to the amount of light produced.
Each of these technologies has a different efficacy in converting electrical energy to visible light. Visible light output is typically measured in lumens.
This unit only quantifies the visible radiation, and excludes invisible infrared and ultraviolet light. A wax candle produces on the close order of 13 lumens, a 60 watt incandescent lamp makes around lumens, and a watt compact fluorescent lamp produces about lumens, but actual output varies by specific design.
Lighting design as it applies to the built environment is known as 'architectural lighting design'. Lighting of structures considers aesthetic elements as well as practical considerations of quantity of light required, occupants of the structure, energy efficiency and cost.
Artificial lighting takes into account the amount of daylight received in an internal space by using Daylight factor calculation. For simple installations, hand-calculations based on tabular data are used to provide an acceptable lighting design. More critical or optimized designs now routinely use mathematical modeling on a computer using software such as Radiance which can allow an Architect to quickly undertake complex calculations to review the benefit of a particular design.
In addition to paint, reflective surfaces also have an effect on lighting design. Photometric studies also sometimes referred to as "layouts" or "point by points" are often used to simulate lighting designs for projects before they are built or renovated.
This enables architects, designers, and engineers to determine which configuration of lighting fixtures will deliver the amount of light needed. Other parameters that can be determined are the contrast ratio between light and dark areas. Depending on the building type, client, or safety requirements, different design aspects may be emphasized for safety or practicality.
Specialized software is often used to create these, which typically combine the use of two-dimensional CAD drawings and lighting calculation software i. AGi32 , Visual, Dialux. Lighting illuminates the performers and artists in a live theatre, dance, or musical performance, and is selected and arranged to create dramatic effects. Stage lighting uses general illumination technology in devices configured for easy adjustment of their output characteristics.
Dimmers, colored filters, reflectors, lenses, motorized or manually aimed lamps, and different kinds of flood and spot lights are among the tools used by a stage lighting designer to produce the desired effects.
A set of lighting cues are prepared so that the lighting operator can control the lights in step with the performance; complex theatre lighting systems use computer control of lighting instruments.
Motion picture and television production use many of the same tools and methods of stage lighting. Especially in the early days of these industries, very high light levels were required and heat produced by lighting equipment presented substantial challenges.
Modern cameras require less light, and modern light sources emit less heat. Measurement of light or photometry is generally concerned with the amount of useful light falling on a surface and the amount of light emerging from a lamp or other source, along with the colors that can be rendered by this light.
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