Spectacles

Although the proposed appHcations for photochromic systems are numerous, few have received broad use. By far, the most successful commercial apphcation is the use of photochromic silver halide-containing glasses in prescription eyewear. The convenience of having lenses that darken automatically upon exposure to sunlight has proven appealing to spectacle wearers (35). With the increasing penetration of plastic lenses into the ophthalmic market, the desire for plastic photochromic ophthalmic lenses has also increased, and considerable effort has been spent on the discovery of photochromic systems for plastic eyewear. 

Today the principal outlets are knife handles, table-tennis balls and spectacle frames. The continued use in knife handles is due to the pleasant appearance and the ability of the material to after-shrink around the extension of the blade. Table-tennis balls continue to be made from celluloid since it has been difficult to match the bounce and handle of the celluloid ball, the type originally used, with balls fabricated from newer polymers. Even here celluloid is now meeting the challenge of synthetic polymers. Spectacle frames are still of interest because of the attractive colour. There are, however, restrictions to their use for this application in certain countries and cellulose acetate is often preferred. 

If the oxygen content of the contaminated air is deficient (refer to page 72), breathing apparatus is essential. The degree of protection required is determined by the level of contamination, the hygiene standard for the contaminant(s), the efficiency of any filter or adsorber available, and the efficiency with which the facepiece of the device seals to the user s face (this is reduced by beards, spectacles etc.). The level of comfort and user acceptability are further considerations. 

Tend to be less comfortable than safety glasses and usually cannot be worn over ordinary spectacles... 

Routing of Flare Header through Process Areas - Flare headers in process areas should be routed to avoid locations of particularly high fire risk, such as over pumps, near furnaces, etc. The headers and subheaders should also be laid out and provided with isolating CSO valves and spectacle blinds, unless prohibited by local codes, such that it is not necessary for flare lines to remain in service in units which are shut down separately. Blowdown and water disengaging drums should be spaced from process areas. 

SPADE POSITION RING FOR RIGID SPECTACLE SPADE... 

Sehen, n. seeing, sight, vision. Sehenswiirdlgkelt,/. sight, spectacle, curiosity. Seher, m. seer. 

Many operations involving chemical reactions are potentially dangerous, and in such cases recommended procedures must be carefully followed and obeyed. All laboratory workers should familiarise themselves with local safety requirements (in some laboratories, the wearing of safety spectacles may be compulsory), and with the position of first-aid equipment. 

Never view the flame or hollow cathode lamps directly protective eye wear should always be worn. Safety spectacles will usually provide adequate protection from ultraviolet light, and will also provide protection for the eyes in the event of the apparatus being shattered by an explosion. 

The application of sulfosuccinates in the field of household products is limited. But when extremely-good wetting properties are desired the short C-chain dialkyl sulfosuccinates are used. Examples are special glass cleansers (beer glass cleaner, spectacle glass cleaner, windscreen cleaner), floor cleaner, and wallpaper stripper. The amount added to the formula is between 0.5% and 2.5%, although for wallpaper stripper up to 20% is used. A typical formulation for a glass cleaner is ... 

Abstract Detectors play a key role in an astronomical observatory. In astronomy, the role of the telescope and instrument is to bring light to a focus - in effect, the telescope-instrument act as spectacles . The detectors, meanwhile, have the critical role of sensing the light - the detectors are the eyes of an observatory. The performance of an astronomical observatory is directly dependent upon the performance of its detector systems. 

Eyes Redness. Safety spectacles. First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor. 

People love the spectacle of fireworks. From Bastille Day in France to Guy Fawkes Day in Britain, from Chinese New Year to Canada Day, fireworks bring joy to celebrations all around the world. In the United States, about 100 million worth of fireworks are discharged every year in honor of Independence Day. Fireworks date back more than 1000 years to the discovery of black powder in China. This first gunpowder was brought to Europe during the Middle Ages and was used widely in weapons, in construction, and for fireworks. 

Most contact lenses are worn for optical reasons as an alternative to spectacles. Contact lenses are of two types, namely hard lenses, which are hydrophobic, and soft lenses, which may be either hydrophilic or hydrophobic. The surfaces of lenses mnst be wetted before nse, and wetting solntions (section 4.5.1) are nsed for this pnrpose. Hard and, more especially, soft lenses become heavily contantinated with protein material dnring nse and must therefore be cleaned (section 4.5.2) before disinfection (section 4.5.3). Contact lenses are potential sonrees of eye infection and conseqnentiy nticroorganisms should be removed before the lens is again inserted into the eye. Lenses mnst also be clean and easily wettable by the lacrimal secretions. Contact-lens solntions are thns sterile solutions of the varions types described below. Apart fiom... 

In all fusing operations with fused silica, protective spectacles must be worn—a glass whch absorbs at least 96 per cent of the incident... 

Behavioral and environmental modifications may significantly improve dry eye, especially in mild cases. Evaluate the patient s environment for air drafts. Consider adding a humidifier in low-humidity areas. Schedule regular breaks from computer work or reading. Lower the computer screen to below eye level to decrease lid aperture. Evaluate medication use and make therapeutic substitutions to medications that do not exacerbate dry eye. Spectacle sideshields or goggles may reduce tear evaporation.30... 

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