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Sunglasses
Sunglasses or sun glasses (informally called shades or sunnies; more names Sunglasses#Other names, below) are a form of Eye protection, protective eyewear designed primarily to prevent bright sunlight and high-energy visible light from damaging or discomforting the eyes. They can sometimes also function as a visual aid, as variously termed spectacles or glasses exist, featuring lenses that are colored, polarizer, polarized or darkened. In the early 20th century, they were also known as sun cheaters (cheaters then being an United States, American slang term for glasses). Since the 1930s, sunglasses have been a popular fashion accessory, especially on the beach. The American Optometric Association recommends wearing sunglasses that block ultraviolet radiation (UV) whenever a person is in the sunlight to protect the eyes from UV and blue light, which can cause several #Protection, serious eye problems. Their usage is mandatory immediately after some surgical procedures, such as L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glasses
Glasses, also known as eyeglasses (American English), spectacles (Commonwealth English), or colloquially as specs, are vision eyewear with clear or tinted lenses mounted in a frame that holds them in front of a person's eyes, typically utilizing a bridge over the nose and hinged arms, known as temples or temple pieces, that rest over the ears for support. Glasses are typically used for vision correction, such as with reading glasses and glasses used for nearsightedness; however, without the specialized lenses, they are sometimes used for cosmetic purposes. Safety glasses are eye protection, a form of personal protective equipment ( PPE) that are worn by workers around their eyes for protection. Safety glasses act as a shield to protect the eyes from any type of foreign debris that may cause irritation or injury; these glasses may have protection on the sides of the eyes as well as in the lenses. Some types of safety glasses are used to protect against visible and n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eye Protection
Eye protection is protective gear for the eyes, and sometimes face, designed to reduce the risk of injury. Examples of risks requiring eye protection can include: impact from particles or debris, light or radiation, wind blast, heat, sea spray or impact from some type of ball or puck used in sports. Eye protection are typically separated into categories based on the style of eye wear and the hazard they are designed to reduce. There categories include: Spectacles with side protection; Goggles; Welding helmet; Welding Hand Shields; Non-Rigid Helmets (hoods); Face shield; and Respirator Face pieces. Styles Spectacles Safety glasses or spectacles, although often used as a catch-all term for all types of eye protection, specifically revers to protective equipment that closely resembles common eye wear. To meet most national standards, spectacles must include side shields to reduce the ability of debris to get behind the lenses from the side. Safety glasses can often moun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smoky Quartz
Smoky quartz is a brownish grey, translucent variety of quartz that ranges in clarity from almost complete transparency to an almost-opaque brownish-gray or black crystals. The color of smoky quartz is produced when natural radiation, emitted from the surrounding rock, activates color centers around aluminum impurities within the crystalline quartz. Varieties Morion is a very dark brown to black opaque variety. Morion is the German, Danish, Spanish and Polish synonym for smoky quartz. The name is from a misreading of ''mormorion'' in Pliny the Elder. Cairngorm is a variety of smoky quartz found in the Cairngorm Mountains of Scotland. It usually has a smoky yellow-brown colour, though some specimens are greyish-brown. It is used in Scottish jewellery and as a decoration on kilt pins and the handles of (anglicised: ''sgian-dubhs'' or ''skean dhu''). The largest known cairngorm crystal is a specimen kept at Braemar Castle. Uses Smoky quartz is common and was not historical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snowblindness
Photokeratitis or ultraviolet keratitis is a painful eye condition caused by exposure of insufficiently protected eyes to the ultraviolet (UV) rays from either natural (e.g. intense direct or reflected sunlight) or artificial (e.g. the electric arc during welding) sources. Photokeratitis is akin to a sunburn of the cornea and conjunctiva. The injury may be prevented by wearing eye protection that blocks most of the ultraviolet radiation, such as welding goggles with the proper filters, a welder's helmet, sunglasses rated for sufficient UV protection, or appropriate snow goggles. The condition is usually managed by removal from the source of ultraviolet radiation, covering the corneas, and administration of pain relief. Photokeratitis is known by a number of different terms, including snow blindness, arc eye, welder's flash, sand eyes, bake eyes, corneal flash burns, flash burns, niphablepsia, or keratoconjunctivitis photoelectrica. Signs and symptoms Common symptoms include ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glare (vision)
Glare is difficulty of seeing in the presence of bright light such as direct or reflected sunlight or artificial light such as car headlamps at night. Because of this, some cars include mirrors with automatic anti-glare functions and in buildings, blinds or louvers are often used to protect occupants. Glare is caused by a significant ratio of luminance between the task (that which is being looked at) and the glare source. Factors such as the angle between the task and the glare source and eye adaptation have significant impacts on the experience of glare. Discomfort and disability Glare can be generally divided into two types, discomfort glare and disability glare. Discomfort glare is a psychological sensation caused by high brightness (or brightness contrast) within the field of view, which does not necessarily impair vision. In buildings, discomfort glare can originate from small artificial lights (e.g. ceiling fixtures) that have brightnesses that are significantly greater tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
China
China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after India, representing 17.4% of the world population. China spans the equivalent of five time zones and Borders of China, borders fourteen countries by land across an area of nearly , making it the list of countries and dependencies by area, third-largest country by land area. The country is divided into 33 Province-level divisions of China, province-level divisions: 22 provinces of China, provinces, 5 autonomous regions of China, autonomous regions, 4 direct-administered municipalities of China, municipalities, and 2 semi-autonomous special administrative regions. Beijing is the country's capital, while Shanghai is List of cities in China by population, its most populous city by urban area and largest financial center. Considered one of six ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emerald
Emerald is a gemstone and a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium or sometimes vanadium.Hurlbut, Cornelius S. Jr., and Kammerling, Robert C. (1991). ''Gemology'', John Wiley & Sons, New York, p. 203, . Beryl has a hardness of 7.5–8 on the Mohs scale. Most emeralds have many inclusions, so their toughness (resistance to breakage) is classified as generally poor. Emerald is a cyclosilicate. Etymology The word "emerald" is derived (via and ), from Vulgar Latin: ''esmaralda/esmaraldus'', a variant of Latin ''smaragdus'', which was via (smáragdos; "green gem"). The Greek word may have a Semitic, Sanskrit or Persian origin. According to ''Webster's Dictionary'' the term emerald was first used in the 14th century. Properties determining value Emeralds, like all colored gemstones, are graded using four basic parameters known as "the four ''C''s": ''color'', ''clarity,'' ''cut'' and ''carat weight''. Normally, in grading ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snow Goggles
Snow consists of individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout its life cycle, starting when, under suitable conditions, the ice crystals form in the atmosphere, increase to millimeter size, precipitate and accumulate on surfaces, then metamorphose in place, and ultimately melt, slide, or Sublimation (phase transition), sublimate away. Snowstorms organize and develop by feeding on sources of atmospheric moisture and cold air. Snowflakes Nucleation, nucleate around particles in the atmosphere by attracting supercooling, supercooled water droplets, which Freezing, freeze in hexagonal-shaped crystals. Snowflakes take on a variety of shapes, basic among these are platelets, needles, columns, and Hard rime, rime. As snow accumulates into a snowpack, it may blow into drifts. Over time, accumulated snow m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nero
Nero Claudius Caesar Augustus Germanicus ( ; born Lucius Domitius Ahenobarbus; 15 December AD 37 – 9 June AD 68) was a Roman emperor and the final emperor of the Julio-Claudian dynasty, reigning from AD 54 until his death in AD 68. Nero was born at Antium in AD 37, the son of Gnaeus Domitius Ahenobarbus (father of Nero), Gnaeus Domitius Ahenobarbus and Agrippina the Younger (great-granddaughter of the emperor Augustus). Nero was three when his father died. By the time Nero turned eleven, his mother married Emperor Claudius, who then Adoption in ancient Rome, adopted Nero as his heir. Upon Claudius' death in AD 54, Nero ascended to the throne with the backing of the Praetorian Guard and the Senate. In the early years of his reign, Nero was advised and guided by his mother Agrippina, his tutor Seneca the Younger, and his praetorian prefect Sextus Afranius Burrus, but sought to rule independently and rid himself of restraining influences. The power ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliny The Elder
Gaius Plinius Secundus (AD 23/24 79), known in English as Pliny the Elder ( ), was a Roman Empire, Roman author, Natural history, naturalist, and naval and army commander of the early Roman Empire, and a friend of the Roman emperor, emperor Vespasian. He wrote the encyclopedic (''Natural History''), a comprehensive thirty-seven-volume work covering a vast array of topics on human knowledge and the natural world, which became an editorial model for encyclopedias. He spent most of his spare time studying, writing, and investigating natural and geographic phenomena in the field. Among Pliny's greatest works was the twenty-volume ''Bella Germaniae'' ("The History of the German Wars"), which is Lost literary work, no longer extant. ''Bella Germaniae'', which began where Aufidius Bassus' ''Libri Belli Germanici'' ("The War with the Germans") left off, was used as a source by other prominent Roman historians, including Plutarch, Tacitus, and Suetonius. Tacitus may have used ''Bella Ger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smithsonian (magazine)
''Smithsonian'' is a magazine covering science, history, art, popular culture and innovation. The first issue was published in 1970. History The history of ''Smithsonian'' began when Edward K. Thompson, the retired editor of ''Life'' magazine, was asked by then-Secretary of the Smithsonian, S. Dillon Ripley, to produce a magazine "about things in which the Smithsonian nstitutionis interested, might be interested or ought to be interested." Thompson later recalled that his philosophy for the new magazine was that it "would stir curiosity in already receptive minds. It would deal with history as it is relevant to the present. It would present art, since true art is never dated, in the richest possible reproduction. It would peer into the future via coverage of social progress and of science and technology. Technical matters would be digested and made intelligible by skilled writers who would stimulate readers to reach upward while not turning them off with jargon. We would fin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
