"with keratoconus. However, they require a period of adaptation before full comfort is achieved. Rigid gas permeable lens A rigid gas permeable lens, also known as RGP lens or GP lens or colloquially, hard contact lens, is a rigid contact lens made of oxygen-permeable polymers. Initially developed in the late 1970s, and through the 1980s and 1990s, they were an improvement over prior 'hard' lenses that restricted oxygen transmission to the eye. Rigid lenses are able to replace the natural shape of the cornea with a new refracting surface. This means that a regular (spherical) rigid contact lens can provide"
"is most commonly known for its use in drinking water purification from seawater, removing the salt and other effluent materials from the water molecules. A process of osmosis through semipermeable membranes was first observed in 1748 by Jean-Antoine Nollet. For the following 200 years, osmosis was only a phenomenon observed in the laboratory. In 1950, the University of California at Los Angeles first investigated desalination of seawater using semipermeable membranes. Researchers from both University of California at Los Angeles and the University of Florida successfully produced fresh water from seawater in the mid-1950s, but the flux was too low to"
"designed and built by the diving engineer Henry Fleuss in 1878, while working for Siebe Gorman in London. His self-contained breathing apparatus consisted of a rubber mask connected to a breathing bag, with (estimated) 50–60% O supplied from a copper tank and CO scrubbed by rope yarn soaked in a solution of caustic potash; the system giving a duration of about three hours. Fleuss tested his device in 1879 by spending an hour submerged in a water tank, then one week later by diving to a depth of 5.5 m in open water, upon which occasion he was slightly injured"
"penetrate through this overheated liquid. The particle expends its energy on ionization of atoms located near its trajectory. This energy loss is transformed into heat in amount which is sufficient to induce boiling along particle’s trajectory. Then the trajectory becomes observable because many bubbles are created along it. G. Askaryan discussed this proposal with some of his teachers and fellow students. No one objected. However, no one supported him, no one helped to realize the idea. G. Askaryan then was inexperienced in forms and methods of scientific investigation. He even did not publish his proposal. Several years later, in 1952,"
"bag placed completely over the head, fastened around the throat with windows through which the wearer could see. Some were rubber, some were made of rubberized fabric, and still others of impregnated fabric, but in most cases a tank of compressed air or a reservoir of air under slight pressure was carried by the wearer to supply the necessary breathing air. In some devices certain means were provided for the adsorption of carbon dioxide in exhaled air and the rebreathing of the same air many times; in other cases valves allowed exhalation of used air. In 1848, the first US"
"or other adsorption techniques are typically used for this. In 1830, a patent was awarded to Charles Anthony Deane for a device comprising a copper helmet with an attached flexible collar and garment. A long leather hose attached to the rear of the helmet was to be used to supply air, the original concept being that it would be pumped using a double bellows. A short pipe allowed breathed air to escape. The garment was to be constructed from leather or airtight cloth, secured by straps. In the 1860s, John Stenhouse filed two patents applying the absorbent properties of wood"
"least since the 5th century BC, when it was invented, and had reached Europe by the 16th century. In 240 BC, The ancient Greek inventor Ctesibius of Alexandria independently invented a double-action piston bellow used to lift water from one level to another. A piston is enclosed in a rectangular box with a handle coming out one side. The piston edges are covered with feathers, fur, or soft paper to ensure that it is airtight and lubricated. As the piston is pulled, air from one side enters and flows through the nozzle and as it is pushed air enters from"
"from an iron reservoir. A similar system was used in 1831 by the American Charles Condert, who died in 1832 while testing his invention in the East River at only deep. The oldest known oxygen rebreather was patented on June 17, 1808 by ""Sieur"" Touboulic from Brest, mechanic in Napoleon's Imperial Navy, but there is no evidence of any prototype having been manufactured. This early rebreather design worked with an oxygen reservoir, the oxygen being delivered progressively by the diver himself and circulating in a closed circuit through a sponge soaked in limewater. After having travelled to England and discovered"
"about the same time, colloidal chemistry began its development, and the concepts of bound water emerged. A colloid being something between a solution and a suspension, where Brownian motion is sufficient to prevent sedimentation. The idea of a semipermeable membrane, a barrier that is permeable to solvent but impermeable to solute molecules was developed at about the same time. The term osmosis originated in 1827 and its importance to physiological phenomena realized, but it wasn’t until 1877, when the botanist Pfeffer proposed the membrane theory of cell physiology. In this view, the cell was seen to be enclosed by a"
"related to meteorites; about the same time, he also obtained oxygen in the solid state. By 1891, he had designed and built, at the Royal Institution, machinery which yielded liquid oxygen in industrial quantities, and towards the end of that year, he showed that both liquid oxygen and liquid ozone are strongly attracted by a magnet. About 1892, the idea occurred to him of using vacuum-jacketed vessels for the storage of liquid gases – the Dewar flask (otherwise known as a Thermos or vacuum flask) – the invention for which he became most famous. The vacuum flask was so efficient"
"1491. The fuel used in these was invariably charcoal. The successful substitution of coke for charcoal is widely attributed to English inventor Abraham Darby in 1709. The efficiency of the process was further enhanced by the practice of preheating the combustion air (hot blast), patented by Scottish inventor James Beaumont Neilson in 1828. Archaeological evidence shows that bloomeries appeared in China around 800 BC. Originally it was thought that the Chinese started casting iron right from the beginning, but this theory has since been debunked by the discovery of 'more than ten' iron digging implements found in the tomb of"
"was first introduced in the US in the 1880s and became popular in some European countries, too. It was state of the art until the 1930s and used concrete ducts, operated with very high temperatures and was therefore not very efficient. There were also problems with reliability and safety due to the hot pressurised steam tubes. Nowadays, this generation is technologically outdated. However, some of these systems are still in use, for example in New York or Paris. Other systems originally built have subsequently been converted to later generations. The second generation was developed in the 1930s and was built"
"air without being continuously replenished by the photosynthetic action of living organisms. Another form (allotrope) of oxygen, ozone (), strongly absorbs ultraviolet UVB radiation and the high-altitude ozone layer helps protect the biosphere from ultraviolet radiation. However, ozone present at the surface is a byproduct of smog and thus a pollutant. Oxygen was isolated by Michael Sendivogius before 1604, but it is commonly believed that the element was discovered independently by Carl Wilhelm Scheele, in Uppsala, in 1773 or earlier, and Joseph Priestley in Wiltshire, in 1774. Priority is often given for Priestley because his work was published first. Priestley,"
"system in 1930 informed Le Corbusier that it would use much more energy than a conventional air system, but Harvey Bryan later concluded Le Corbusier's idea had merit if it included solar heating. Another early experiment was the 1937 Alfred Loomis house by architect William Lescaze in Tuxedo Park, NY. This house included ""an elaborate double envelope"" with a 2-foot-deep air space conditioned by a separate system from the house itself. The object was to maintain high humidity levels inside. One of the first modern examples to be constructed was the Occidental Chemical Building (Niagara Falls, New York, 1980) by"
"as a heat-sink, but unable to be burnt. In addition a condenser isn't required, giving a weight saving. Robert P. Carmichael in 1955 devised several engine cycles that used liquid hydrogen to precool the inlet air to the engine before using it as fuel. Interest in precooled engines saw an emergence in the UK in 1982, when Alan Bond created a precooled air breathing rocket engine design he called SATAN. The idea was developed as part of the HOTOL SSTO spaceplane project, and became the Rolls-Royce RB545. In 1989, after the HOTOL project was discontinued, some of the RB545 engineers"
"Olszewski. In 1891 Scottish chemist James Dewar was able to produce enough liquid oxygen for study. The first commercially viable process for producing liquid oxygen was independently developed in 1895 by German engineer Carl von Linde and British engineer William Hampson. Both men lowered the temperature of air until it liquefied and then distilled the component gases by boiling them off one at a time and capturing them separately. Later, in 1901, oxyacetylene welding was demonstrated for the first time by burning a mixture of acetylene and compressed . This method of welding and cutting metal later became common. In"
"was incidentally manufactured by humans since pre-historical times, by the combustion of carbon-containing substances and fermentation of foods such as beer and bread. It was gradually recognized as a chemical substance, formerly called ""spiritus sylvestris"" (""forest spirit"") or ""fixed air"", by various chemists in the 17th and 18th centuries. Carbon monoxide may occur in combustion, too, and was used (though not recognized) since antiquity for the smelting of iron from its ores. Like the dioxide, it was described and studied in the West by various alchemists and chemists since the Middle Ages. Its true composition was discovered by William Cruikshank"
"dioxide rendering them of limited use. Theodore Schwann, a German professor working in Belgium, designed breathing apparatus based on the regenerative process in 1854 and it was exhibited in Paris in the 1870s but may never have been used. Henry Fleuss developed Schwann's apparatus into a form of self-contained breathing apparatus in the 1880s and it was used after an explosion at Seaham Colliery in 1881. The apparatus was further developed by Siebe Gorman into the Proto rebreather. In 1908 the Proto apparatus was chosen in a trial of equipment from several manufacturers to select the most efficient apparatus for"
"in Melbourne. He designed it primarily to drill rock and to dig coal. 1892 – Coolgardie safe – Arthur Patrick McCormick noticed that a wet bag placed over a bottle cooled its contents, and the cooling was more pronounced in a breeze. The Coolgardie safe was a box made of wire and hessian sitting in water, which was placed on a verandah so that any breeze would evaporate the water in the hessian and via the principle of evaporation, cool the air inside the box. The Coolgardie safe was used into the middle of the 20th century as a means"
"Kolff believed that doctors should make technology available to all, without mind to profit. The early artificial lungs used relatively impermeable polyethylene or Teflon homogeneous membranes, and it was not until more highly permeable silicone rubber membranes were introduced in the 1960s (and as hollow fibres in 1971) that the membrane oxygenator became commercially successful. The introduction of microporous hollow fibres with very low resistance to mass transfer revolutionized the design of membrane modules, as the limiting factor to oxygenator performance became the blood resistance. Current designs of oxygenator typically use an extraluminal flow regime, where the blood flows outside"
"Henry Fleuss in 1878, while working for Siebe Gorman in London. His self contained breathing apparatus consisted of a rubber mask connected to a breathing bag, with an estimated 50–60% oxygen supplied from a copper tank and carbon dioxide scrubbed by passing it through a bundle of rope yarn soaked in a solution of caustic potash, the system giving a dive duration of up to about three hours. Fleuss tested his device in 1879 by spending an hour submerged in a water tank, then one week later by diving to a depth of in open water, on which occasion he"
"the invention of the Coolgardie safe. The safe was invented in the late 1890s by Arthur Patrick McCormick, who used the same principle as explorers and travelers in the Outback used to cool their canvas water bags: when the canvas bag is wet the fibers expand and it holds water. Some water seeps out and evaporates. It is most effective when air continually moves past it, such as when in a moving vehicle or when exposed to a breeze. This technology is commonly thought to have been adopted by explorer and scientist Thomas Mitchell, who had observed the way some"
"for British vessels until 1998. Frequently vegetable oil or fish oil was used as a cheap form of oil. Oil has a dampening effect on water which absorbs some of the energy of the waves. It also quickly forms a thin layer over a large expanse of the surface of the water through a process of deprotonation. This prevents wind from being able to get traction along the water and thus waves cannot form as easily. The practice can be traced back as far as 350 BCE with Aristotle and to the early 1st century with Pliny the Elder. Aristotle"
"of his attempts to decompose air. Nineteen years later Louis Jacques Thénard recognized that this compound could be used for the preparation of a previously unknown compound, which he described as ""eau oxygénée"" (French: oxygenated water) – subsequently known as hydrogen peroxide. (Today this term refers instead to water containing dissolved oxygen (O).) An improved version of Thénard's process used hydrochloric acid, followed by addition of sulfuric acid to precipitate the barium sulfate byproduct. This process was used from the end of the 19th century until the middle of the 20th century. Thénard and Joseph Louis Gay-Lussac synthesized sodium peroxide"
"methods resulted in the rise of the annual production of hydrogen peroxide from 35,000 tonnes in 1950, to over 100,000 tonnes in 1960, to 300,000 tonnes by 1970; by 1998 it reached 2.7 million tonnes. Pure hydrogen peroxide was long believed to be unstable, as early attempts to separate it from the water, which is present during synthesis, all failed. This instability was due to traces of impurities (transition-metal salts), which catalyze the decomposition of the hydrogen peroxide. Pure hydrogen peroxide was first obtained in 1894—almost 80 years after its discovery—by Richard Wolffenstein, who produced it by vacuum distillation. Determination"
"as a membrane to filter the salt. There are numerous other examples of experimentation in desalination throughout Antiquity and the Middle Ages, but desalination was never feasible on a large scale until the modern era. Before the Industrial Revolution, desalination was primarily of concern to oceangoing ships, which otherwise needed to keep on board supplies of fresh water. When Protector (1779 frigate) was sold to Denmark in the 1780s (as the ship Hussaren) the desalination plant was studied and recorded in great detail. In the newly formed United States, Thomas Jefferson catalogued heat-based methods going back to the 1500s, and"
"and oxygen in chemicals, pharmaceuticals and environmental samples. This development was made possible through the experience gained in the high temperature furnace technology needed for melting of platinum, which has a high melting point of 1770 degrees Celsius. Building on the know-how in handling high temperatures for chemical processes, Richard Küch, a researcher at the Heraeus Platinum Smelting Factory, was able to produce quartz glass of very high purity, which is still the material of choice for combustion tubes used in modern combustion analyzers. Richard Küch’s invention together with the experience in high temperature furnace technology resulted in the commercial"
"to find the best way to prevent the carbon dioxide or bubbles from escaping. The bottles could also explode if the pressure was too great. Hiram Codd devised a patented bottling machine while working at a small mineral water works in the Caledonian Road, Islington, in London in 1870. His Codd-neck bottle was designed to enclose a marble and a rubber washer in the neck. The bottles were filled upside down, and pressure of the gas in the bottle forced the marble against the washer, sealing in the carbonation. The bottle was pinched into a special shape to provide a"
"be ubiquitously distributed in space, making it a viable candidate for the carrier."" In 1987, Kroto also proposed that ""The present observations indicate that C might survive in the general medium (probably as the ion C) protected by its unique ability to survive processes so drastic that most, if not all, other known molecules are destroyed."" The achievement in 2015 was the result of many years of work, performed by the group of John Maier at the University of Basel, developing state of the art spectroscopic techniques to create conditions in the laboratory that simulated the extremely low temperature and"
"as far back as the early 19th century. Another insulating gum which could be melted by heat and readily applied to wire made its appearance in 1842. Gutta-percha, the adhesive juice of the ""Palaquium gutta"" tree, was introduced to Europe by William Montgomerie, a Scottish surgeon in the service of the British East India Company. Twenty years earlier, Montgomerie had seen whips made of gutta-percha in Singapore, and he believed that it would be useful in the fabrication of surgical apparatuses. Michael Faraday and Wheatstone soon discovered the merits of gutta-percha as an insulator, and in 1845, the latter suggested"
"1900s, were derived from it. Professor Georges Jaubert invented the chemical compound Oxylithe in 1907. It was a form of sodium peroxide (NaO) or sodium superoxide (NaO). As it absorbs carbon dioxide in a rebreather's scrubber it emits oxygen. This compound was first incorporated into a rebreather design by Captain S.S. Hall and Dr. O. Rees of the Royal Navy in 1909. Although intended for use as a submarine escape apparatus, it was never accepted by the Royal Navy and was instead used for shallow water diving. In 1912 the German firm Dräger began mass production of their own version"
"This can be used for air conditioning and refrigeration and the nutrient-rich deep ocean water can feed biological technologies. Another by-product is fresh water distilled from the sea. OTEC theory was first developed in the 1880s and the first bench size demonstration model was constructed in 1926. Currently the world's only operating OTEC plant is in Japan, overseen by Saga University. Attempts to develop and refine OTEC technology started in the 1880s. In 1881, Jacques Arsene d'Arsonval, a French physicist, proposed tapping the thermal energy of the ocean. D'Arsonval's student, Georges Claude, built the first OTEC plant, in Matanzas, Cuba"
"the expansion of steam in a steam engine. There have been prototype cars since the 1920s, with compressed air used in torpedo propulsion. In contrast to hydrogen's issues of damage and danger involved in high-impact crashes, air, on its own, is non-flammable, it was reported on Seven Network's ""Beyond Tomorrow"" that on its own carbon-fiber is brittle and can split under sufficient stress, but creates no shrapnel when it does so. Carbon-fiber tanks safely hold air at a pressure somewhere around 4500 psi, making them comparable to steel tanks. The cars are designed to be filled up at a high-pressure"