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Task Lighting
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. Different strategies for task lighting exist. The three main approaches are: * Localized average lighting, where a lamp supplies both ambient light and task light * Freely adjustable task light such as a gooseneck, balanced-arm lamp, or swing-arm light. * Asymmetric task light, where the lamp is placed at the side of the work area There are also other approaches to task lighting, for example under-shelf luminaires. Other instances of task lighting are in machinery, where a specific wor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Illuminance
In photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate with human brightness perception.International Electrotechnical Commission (IEC): ''International Electrotechnical Vocabulary.'ref. 845-21-060, illuminance/ref> Similarly, luminous emittance is the luminous flux per unit area emitted from a surface. Luminous emittance is also known as luminous exitance. In SI units illuminance is measured in lux (lx), or equivalently in lumens per square metre ( lm· m−2). Luminous exitance is measured in lm·m−2 only, not lux. International Electrotechnical Commission (IEC): ''International Electrotechnical Vocabulary.'ref. 845-21-081, luminous exitance/ref> In the CGS system, the unit of illuminance is the phot, which is equal to . The foot-candle is a non-metric unit of illuminance that is used in photography. Ill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contrast (vision)
Contrast is the contradiction in luminance or colour that makes an object (or its representation in an image or display) distinguishable. In visual perception of the real world, contrast is determined by the difference in the colour and brightness of the object and other objects within the same field of view. The human visual system is more sensitive to contrast than absolute luminance; we can perceive the world similarly regardless of the huge changes in illumination over the day or from place to place. The maximum ''contrast'' of an image is the contrast ratio or dynamic range. Images with a contrast ratio close to their medium's maximum possible contrast ratio experience a ''conservation of contrast'', wherein any increase in contrast in some parts of the image must necessarily result in a decrease in contrast elsewhere. Brightening an image will increase contrast in dark areas but decrease contrast in bright areas, while darkening the image will have the opposite effect. B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balanced-arm Lamp
A balanced-arm lamp, sometimes called a floating arm lamp, is a lamp with an adjustable folding arm which is constructed such that the force due to gravity is always counteracted by springs, regardless of the position of the arms of the lamp. Many lamp brands (such as the Anglepoise, originator of the concept, and Luxo L-1), as well as other devices, use this principle. Configuration The five terms This article uses the terminology: * ''lamp cap'', * ''forearm'', * ''upper arm'', * ''stand'' or ''body'' and * ''base'' for the five basic parts of these lamps. The general design A balanced-arm lamp has a ''base'', a ''stand'' or ''body'', (in most cases) ''two'' connected ''arms'' (in many cases fitted with springs), and a ''lamp-head''. The lamp can be moved into almost any position, and the balancing device will maintain the position until moved again. The same overall mechanism can be employed in ''other'' devices with similar requirements, such as: * copy holders for t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminaire
A light fixture (US English), light fitting (UK English), or luminaire is an electrical device containing an electric lamp that provides illumination. All light fixtures have a fixture body and one or more lamps. The lamps may be in sockets for easy replacement—or, in the case of some LED fixtures, hard-wired in place. Fixtures may also have a switch to control the light, either attached to the lamp body or attached to the power cable. Permanent light fixtures, such as dining room chandeliers, may have no switch on the fixture itself, but rely on a wall switch. Fixtures require an electrical connection to a power source, typically AC mains power, but some run on battery power for camping or emergency lights. Permanent lighting fixtures are directly wired. Movable lamps have a plug and cord that plugs into a wall socket. Light fixtures may also have other features, such as reflectors for directing the light, an aperture (with or without a lens), an outer shell or housing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medicine
Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness. Contemporary medicine applies biomedical sciences, biomedical research, genetics, and medical technology to diagnose, treat, and prevent injury and disease, typically through pharmaceuticals or surgery, but also through therapies as diverse as psychotherapy, external splints and traction, medical devices, biologics, and ionizing radiation, amongst others. Medicine has been practiced since prehistoric times, and for most of this time it was an art (an area of skill and knowledge), frequently having connections to the religious and philosophical beliefs of local culture. For example, a medicine man would apply herbs and say prayers for healing, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surgery
Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pathological condition such as a disease or injury, to help improve bodily function, appearance, or to repair unwanted ruptured areas. The act of performing surgery may be called a surgical procedure, operation, or simply "surgery". In this context, the verb "operate" means to perform surgery. The adjective surgical means pertaining to surgery; e.g. surgical instruments or surgical nurse. The person or subject on which the surgery is performed can be a person or an animal. A surgeon is a person who practices surgery and a surgeon's assistant is a person who practices surgical assistance. A surgical team is made up of the surgeon, the surgeon's assistant, an anaesthetist, a circulating nurse and a surgical technologist. Surgery usually spa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentist
A dentist, also known as a dental surgeon, is a health care professional who specializes in dentistry (the diagnosis, prevention, management, and treatment of diseases and conditions of the mouth, oral cavity and other aspects of the craniofacial complex including the temporomandibular joint). The dentist's Dental auxiliary, supporting team aids in providing oral health services. The dental team includes dental assistants, dental hygienists, dental technicians, and sometimes dental therapists. History Middle Ages In China as well as France, the first people to perform dentistry were barbers. They have been categorized into 2 distinct groups: guild of barbers and lay barbers. The first group, the Guild of Barbers, was created to distinguish more educated and qualified dental surgeons from lay barbers. Guild barbers were trained to do complex surgeries. The second group, the lay barbers, were qualified to perform regular hygienic services such as shaving and tooth extraction as w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recessed Light
A recessed light or downlight (also pot light in Canadian English, sometimes can light (for canister light) in American English) is a light fixture that is installed into a hollow opening in a ceiling. When installed it appears to have light shining from a hole in the ceiling, concentrating the light in a downward direction as a broad floodlight or narrow spotlight. "Pot light" or "canister light" implies the hole is circular and the lighting fixture is cylindrical, like a pot or canister. There are three parts to a recessed lighting fixture: housing, trim and bulb. The trim is the visible portion of the light. It is the insert that is seen when looking up into the fixture, and also includes the thin lining around the edge of the light. The housing is the fixture itself that is installed inside the ceiling and contains the lamp holder. There are many different types of bulbs that can be inserted into recessed lighting fixtures, with the amount of heat generated by the bulb bein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cooking
Cooking, cookery, or culinary arts is the art, science and craft of using heat to Outline of food preparation, prepare food for consumption. Cooking techniques and ingredients vary widely, from grilling food over an open fire to using electric stoves, to baking in various types of ovens, reflecting local conditions. Types of cooking also depend on the skill levels and training of the Cook (profession), cooks. Cooking is done both by people in their own dwellings and by professional cooks and chefs in restaurants and other food establishments. Preparing food with heat or fire is an activity unique to humans. Archeological evidence of cooking fires from at least 300,000 years ago exists, but some estimate that humans started cooking up to 2 million years ago. The expansion of agriculture, commerce, trade, and transportation between civilizations in different regions offered cooks many new ingredients. New inventions and technologies, such as the invention of pottery for holding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sewing
Sewing is the craft of fastening or attaching objects using stitches made with a sewing needle and thread. Sewing is one of the oldest of the textile arts, arising in the Paleolithic era. Before the invention of spinning yarn or weaving fabric, archaeologists believe Stone Age people across Europe and Asia sewed fur and leather clothing using bone, antler or ivory sewing-needles and "thread" made of various animal body parts including sinew, catgut, and veins. For thousands of years, all sewing was done by hand. The invention of the sewing machine in the 19th century and the rise of computerization in the 20th century led to mass production and export of sewn objects, but hand sewing is still practiced around the world. Fine hand sewing is a characteristic of high-quality tailoring, haute couture fashion, and custom dressmaking, and is pursued by both textile artists and hobbyists as a means of creative expression. The first known use of the word "sewing" was in the 14th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reading (process)
Reading is the process of taking in the sense or meaning of letters, symbols, etc., especially by sight or touch. For educators and researchers, reading is a multifaceted process involving such areas as word recognition, orthography (spelling), alphabetics, phonics, phonemic awareness, vocabulary, comprehension, fluency, and motivation. Other types of reading and writing, such as pictograms (e.g., a hazard symbol and an emoji), are not based on speech-based writing systems. The common link is the interpretation of symbols to extract the meaning from the visual notations or tactile signals (as in the case of Braille). Overview Reading is typically an individual activity, done silently, although on occasion a person reads out loud for other listeners; or reads aloud for one's own use, for better comprehension. Before the reintroduction of separated text (spaces between words) in the late Middle Ages, the ability to read silently was considered rather remarkable. Major pred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Architectural Lighting Design
Architectural lighting design is a field of work or study that is concerned with the design of lighting systems within the built environment, both interior and exterior. It can include manipulation and design of both daylight and electric light or both, to serve human needs. Lighting design is based in both science and the visual arts. The basic aim of lighting within the built environment is to enable occupants to see clearly and without discomfort. The objective of architectural lighting design is to balance the art and the science of lighting to create mood, visual interest and enhance the experience of a space or place whilst still meeting the technical and safety requirements. Overview The purpose of architectural lighting design is to balance the characteristics of light within a space to optimize the technical, the visual and, most recently, the non-visual components of ergonomics with respect to illumination of buildings or spaces. The technical requiremen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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