World War II
World War II known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries; the major participants threw their entire economic and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 50 to 85 million fatalities, most of whom were civilians in the Soviet Union and China, it included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, the only use of nuclear weapons in war. Japan, which aimed to dominate Asia and the Pacific, was at war with China by 1937, though neither side had declared war on the other. World War II is said to have begun on 1 September 1939, with the invasion of Poland by Germany and subsequent declarations of war on Germany by France and the United Kingdom.
From late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Finland and the Baltic states. Following the onset of campaigns in North Africa and East Africa, the fall of France in mid 1940, the war continued between the European Axis powers and the British Empire. War in the Balkans, the aerial Battle of Britain, the Blitz, the long Battle of the Atlantic followed. On 22 June 1941, the European Axis powers launched an invasion of the Soviet Union, opening the largest land theatre of war in history; this Eastern Front trapped most crucially the German Wehrmacht, into a war of attrition. In December 1941, Japan launched a surprise attack on the United States as well as European colonies in the Pacific. Following an immediate U. S. declaration of war against Japan, supported by one from Great Britain, the European Axis powers declared war on the U.
S. in solidarity with their Japanese ally. Rapid Japanese conquests over much of the Western Pacific ensued, perceived by many in Asia as liberation from Western dominance and resulting in the support of several armies from defeated territories; the Axis advance in the Pacific halted in 1942. Key setbacks in 1943, which included a series of German defeats on the Eastern Front, the Allied invasions of Sicily and Italy, Allied victories in the Pacific, cost the Axis its initiative and forced it into strategic retreat on all fronts. In 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained its territorial losses and turned toward Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in Central China, South China and Burma, while the Allies crippled the Japanese Navy and captured key Western Pacific islands; the war in Europe concluded with an invasion of Germany by the Western Allies and the Soviet Union, culminating in the capture of Berlin by Soviet troops, the suicide of Adolf Hitler and the German unconditional surrender on 8 May 1945.
Following the Potsdam Declaration by the Allies on 26 July 1945 and the refusal of Japan to surrender under its terms, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August respectively. With an invasion of the Japanese archipelago imminent, the possibility of additional atomic bombings, the Soviet entry into the war against Japan and its invasion of Manchuria, Japan announced its intention to surrender on 15 August 1945, cementing total victory in Asia for the Allies. Tribunals were set up by fiat by the Allies and war crimes trials were conducted in the wake of the war both against the Germans and the Japanese. World War II changed the political social structure of the globe; the United Nations was established to foster international co-operation and prevent future conflicts. The Soviet Union and United States emerged as rival superpowers, setting the stage for the nearly half-century long Cold War. In the wake of European devastation, the influence of its great powers waned, triggering the decolonisation of Africa and Asia.
Most countries whose industries had been damaged moved towards economic expansion. Political integration in Europe, emerged as an effort to end pre-war enmities and create a common identity; the start of the war in Europe is held to be 1 September 1939, beginning with the German invasion of Poland. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred and the two wars merged in 1941; this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935; the British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the fo
Textile manufacturing is a major industry. It is based on the conversion of fiber into yarn into fabric; these are dyed or printed, fabricated into clothes. Different types of fibers are used to produce yarn. Cotton remains the most important natural fiber. There are many variable processes available at the spinning and fabric-forming stages coupled with the complexities of the finishing and colouration processes to the production of a wide ranges of products. There remains a large industry. Cotton is the world's most important natural fibre. In the year 2007, the global yield was 25 million tons from 35 million hectares cultivated in more than 50 countries. There are six stages: Cultivating and Harvesting Preparatory Processes Spinning Weaving or Knitting Finishing Marketing Cotton is grown anywhere with long, hot dry summers with plenty of sunshine and low humidity. Indian cotton, gossypium arboreum, is finer but the staple is only suitable for hand processing. American cotton, gossypium hirsutum, produces the longer staple needed for machine production.
Planting is from September to mid November and the crop is harvested between March and June. The cotton bolls are harvested by stripper harvesters and spindle pickers, that remove the entire boll from the plant; the cotton boll is the seed pod of the cotton plant, attached to each of the thousands of seeds are fibres about 2.5 cm long. GinningThe seed cotton goes into a Cotton gin; the cotton gin removes the "trash" from the fibre. In a saw gin, circular saws grab the fibre and pull it through a grating, too narrow for the seeds to pass. A roller gin is used with longer staple cotton. Here a leather roller captures the cotton. A knife blade, set close to the roller, detaches the seeds by drawing them through teeth in circular saws and revolving brushes which clean them away; the ginned cotton fibre, known as lint, is compressed into bales which are about 1.5 m tall and weigh 220 kg. Only 33% of the crop is usable lint. Commercial cotton is priced by quality, that broadly relates to the average length of the staple, the variety of the plant.
Longer staple cotton is called Egyptian, medium staple is called American upland and short staple is called Indian. The cotton seed is pressed into a cooking oil; the husks and meal are processed into animal feed, the stems into paper. Ginning, bale-making and transportation is done in the country of origin. Opening and cleaning Cotton mills get the cotton shipped to them in 500 pound bales; when the cotton comes out of a bale, it still contains vegetable matter. The bale is broken open using a machine with large spikes, it is called an Opener. In order to fluff up the cotton and remove the vegetable matter, the cotton is sent through a picker, or similar machines; the cotton is fed into a machine known as a picker, gets beaten with a beater bar in order to loosen it up. It is fed through various rollers; the cotton, aided by fans collects on a screen and gets fed through more rollers till it emerges as a continuous soft fleecy sheet, known as a lap. Blending and ScutchingScutching refers to the process of cleaning cotton of its seeds and other impurities.
The first scutching machine was invented in 1797, but did not come into further mainstream use until after 1808 or 1809, when it was introduced and used in Manchester, England. By 1816, it had become adopted; the scutching machine worked by passing the cotton through a pair of rollers, striking it with iron or steel bars called beater bars or beaters. The beaters, which turn quickly, strike the cotton hard and knock the seeds out; this process is done over a series of parallel bars so as to allow the seeds to fall through. At the same time, air is blown across the bars. Carding Carding: the fibres are separated and assembled into a loose strand at the conclusion of this stage; the cotton comes off of the picking machine in laps, is taken to carding machines. The carders line up the fibres nicely to make them easier to spin; the carding machine consists of one big roller with smaller ones surrounding it. All of the rollers are covered in small teeth, as the cotton progresses further on the teeth get finer.
The cotton leaves the carding machine in the form of a sliver. Note: In a wider sense Carding can refer to these four processes: Willowing- loosening the fibres. Combing is used to remove the shorter fibres, creating a stronger yarn. Drawing the fibres are straightenedSeveral slivers are combined; each sliver will have thin and thick spots, by combining several slivers together a more consistent size can be reached. Since combining several slivers produces a thick rope of cotton fibres, directly after being combined the slivers are separated into rovings; these rovings are what are used in the spinning process. Speaking, for machine processing, a roving is about the width of a pencil. Drawing frame: Draws the strand out Slubbing Frame: adds twist, winds onto bobbins Intermediate Frames: are used to repeat the slubbing process to produce a finer yarn. Roving frames: reduces to a finer thread, gives more twist, makes more regular and in thickness, winds onto a smaller tube. Sp
A spinneret is a device used to extrude a polymer solution or polymer melt to form fibers. Streams of viscous polymer exit via the spinneret into air or liquid leading to a phase inversion which allows the polymer to solidify; the individual polymer chains tend to align in the fiber because of viscous flow. This airstream liquid-to-fiber formation process is similar to the production process for cotton candy; the fiber production process is referred to as "spinning". Depending on the type of spinneret used, either solid or hollow fibers can be formed. Spinnerets are used for electrospinning and electrospraying applications, they are sometimes called coaxial emitters. Spinnerets are made of metals with melting points too low to withstand the heating processes employed in industrial metallurgy, thus are not used in constructing metals. A typical technical table can be found at ske website with some typical examples applications. Electrospinning Hollow fiber membrane Spinning Textiles Thermal cleaning
Xanthate refers to a salt with the formula ROCS−2M+, thus O-esters of dithiocarbonate. The name xanthates is derived from Greek ξανθός xanthos, meaning “yellowish, golden”, indeed most xanthate salts are yellow, they were named in 1823 by Danish chemist William Christopher Zeise. These organosulfur compounds are important in two areas: the production of cellophane and related polymers from cellulose and for extraction of certain ores, they are versatile intermediates in organic synthesis. Xanthates refer to esters of xanthic acid; these esters have the structure ROCSR′. Xanthate salts are produced by the reaction of an alkoxide salt with carbon disulfide; the reaction involves the attack of the alkoxide nucleophile on the electrophile CS2. The alkoxide is generated in situ by treating the alcohol with sodium or potassium hydroxide: ROH + CS2 + KOH → ROCS2K + H2OFor example, sodium ethoxide gives sodium ethyl xanthate. Many alcohols can be used in this reaction. Technical grade xanthate salts are of 90–95% purity.
Impurities include alkali-metal sulfides, trithiocarbonates, sulfites, or carbonates as well as residual raw material such as alcohol and alkali hydroxide. These salts are available commercially as powder, flakes and solutions are available; some commercially important xanthate salts include: sodium ethyl xanthate CH3CH2OCS2Na potassium ethyl xanthate, CH3CH2OCS2K sodium isopropyl xanthate, 2CHOCS2Na sodium isobutyl xanthate, 2CHCH2OCS2Na potassium amyl xanthate, CH34OCS2KThe OCS2 core of xanthate salts, like that of the all-oxygen carbonates and other simple esters is characteristically planar. The central carbon is sp2-hybridized. Xanthate salts characteristically decompose in acid: ROCS2K + HCl → ROH + CS2 + KClThis reaction is the reverse of the method for the preparation of the xanthate salts; the intermediate in the decomposition is the xanthic acid, ROCSH, which can be isolated in certain cases. Xanthate anions undergo alkylation to give xanthate esters, which are stable: ROCS2K + R′X → ROCSR′ + KXThe C-O bond in these compounds are susceptible to cleavage by the Barton–McCombie deoxygenation, which provides a means for deoxygenation of alcohols.
They can be oxidized to the so-called dixanthogens: 2 ROCS2Na + Cl2 → ROCS2COR + 2 NaClXanthates bind to transition metal cations as bidentate ligands. The charge-neutral complexes are soluble in organic solvents. Cellulose reacts with carbon disulfide in presence of sodium hydroxide to produces sodium cellulose xanthate, which upon neutralization with sulfuric acid gives viscose rayon or cellophane paper. Certain xanthate salts and bisxanthates are used as flotation agents in mineral processing, they are intermediates in the Chugaev elimination process and are used to control radical polymerisation under the RAFT process termed MADIX. Encountered, thioxanthates arise by the reaction of CS2 with thiolate salts. For example, sodium ethylthioxanthate has the formula C2H5SCS2Na. Dithiocarbamates are related compounds, they arise from the reaction of a secondary amine with CS2. For example, sodium diethyldithiocarbamate has the formula 2NCS2Na. Xanthates may be toxic to aquatic life at concentrations of less than 1 mg/L.
Water downstream of mining operations is contaminated
A parachute is a device used to slow the motion of an object through an atmosphere by creating drag. Parachutes are made out of light, strong fabric silk, now most nylon, they are dome-shaped, but vary, with rectangles, inverted domes, others found. A variety of loads are attached to parachutes, including people, equipment, space capsules, bombs. A drogue chute is used to aid horizontal deceleration of a vehicle including fixed-wing aircraft and drag racers, provide stability, as to assist certain types of light aircraft in distress, tandem free-fall; the earliest fictional account of a parachute type of device was made some 4,000 years ago when the Chinese noticed that air resistance would slow a person's fall from a height. The Western Han Dynasty writer Sima Qian in his book Historical Records recounts the story of Shun, a legendary Chinese emperor who ran away from his murderous father by climbing onto the top of a high granary; as there was nowhere to go, Shun grabbed two bamboo hats and leaped off and glided downward to safety.
The earliest evidence for the modern parachute dates back to the Renaissance period. The oldest parachute design appears in an anonymous manuscript from 1470s Renaissance Italy, showing a free-hanging man clutching a crossbar frame attached to a conical canopy; as a safety measure, four straps ran from the ends of the rods to a waist belt, marked improvement over another folio, which depicts a man trying to break the force of his fall by the means of two long cloth streamers fastened to two bars which he grips with his hands. Although the surface area of the first design appears to be too small to be effective and the wooden frame is superfluous and harmful, the basic concept of a working parachute is apparent. Shortly after, a more sophisticated parachute was sketched by the polymath Leonardo da Vinci in his Codex Atlanticus dated to ca. 1485. Here, the scale of the parachute is in a more favorable proportion to the weight of the jumper. Leonardo's canopy was held open by a square wooden frame, which alters the shape of the parachute from conical to pyramidal.
It is not known whether the Italian inventor was influenced by the earlier design, but he may have learned about the idea through the intensive oral communication among artist-engineers of the time. The feasibility of Leonardo's pyramidal design was tested in 2000 by Briton Adrian Nicholas and again in 2008 by the Swiss skydiver Olivier Vietti-Teppa. According to the historian of technology Lynn White, these conical and pyramidal designs, much more elaborate than early artistic jumps with rigid parasols in Asia, mark the origin of "the parachute as we know it." The Dalmatian polymath and inventor Fausto Veranzio examined da Vinci's parachute sketch and kept the square frame but replaced the canopy with a bulging sail-like piece of cloth that he came to realize decelerates a fall more effectively. A now-famous depiction of a parachute that he dubbed Homo Volans, showing a man parachuting from a tower St Mark's Campanile in Venice, appeared in his book on mechanics, Machinae Novae, alongside a number of other devices and technical concepts.
It was once believed that in 1617, Veranzio aged 65 and ill, implemented his design and tested the parachute by jumping from St Mark's Campanile, from a bridge nearby, or from St Martin's Cathedral in Bratislava. In various publications it was incorrectly claimed the event was documented some thirty years by John Wilkins and secretary of the Royal Society in London, in his book Mathematical Magick or, the Wonders that may be Performed by Mechanical Geometry, published in London in 1648. However, Wilkins wrote about flying, not parachutes, does not mention Veranzio, a parachute jump, or any event in 1617. Doubts about this test, which include a lack of written evidence, suggest it never occurred, was instead a misreading of historical notes; the modern parachute was invented in the late 18th century by Louis-Sébastien Lenormand in France, who made the first recorded public jump in 1783. Lenormand sketched his device beforehand. Two years in 1785, Lenormand coined the word "parachute" by hybridizing an Italian prefix para, an imperative form of parare = to avert, resist, shield or shroud, from paro = to parry, chute, the French word for fall, to describe the aeronautical device's real function.
In 1785, Jean-Pierre Blanchard demonstrated it as a means of safely disembarking from a hot-air balloon. While Blanchard's first parachute demonstrations were conducted with a dog as the passenger, he claimed to have had the opportunity to try it himself in 1793 when his hot air balloon ruptured and he used a parachute to descend. Subsequent development of the parachute focused on it becoming more compact. While the early parachutes were made of linen stretched over a wooden frame, in the late 1790s, Blanchard began making parachutes from folded silk, taking advantage of silk's strength and light weight. In 1797, André Garnerin made the first descent of a "frameless" parachute covered in silk. In 1804 Jérôme Lalande introduced a vent in the canopy to eliminate violent oscillations. In 1907 Charles Broadwick demonstrated two key advances in the parachute he used to jump from hot air balloons at fairs: he folded his parachute into a pack he wore on his back and the parachute was pulled from the pack by a static line attached to the balloon.
When Broadwick jumped from the balloon, the static line became taut, pulled th
Incandescent light bulb
An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated to such a high temperature that it glows with visible light. The filament is protected from oxidation with a glass or fused quartz bulb, filled with inert gas or a vacuum. In a halogen lamp, filament evaporation is slowed by a chemical process that redeposits metal vapor onto the filament, thereby extending its life; the light bulb is supplied with electric current by feed-through terminals or wires embedded in the glass. Most bulbs are used in a socket which provides electrical connections. Incandescent bulbs are manufactured in a wide range of sizes, light output, voltage ratings, from 1.5 volts to about 300 volts. They require no external regulating equipment, have low manufacturing costs, work well on either alternating current or direct current; as a result, the incandescent bulb is used in household and commercial lighting, for portable lighting such as table lamps, car headlamps, flashlights, for decorative and advertising lighting.
Incandescent bulbs are much less efficient than other types of electric lighting. The remaining energy is converted into heat; the luminous efficacy of a typical incandescent bulb for 120 V operation is 16 lumens per watt, compared with 60 lm/W for a compact fluorescent bulb or 150 lm/W for some white LED lamps. Some applications of the incandescent bulb deliberately use the heat generated by the filament; such applications include incubators, brooding boxes for poultry, heat lights for reptile tanks, infrared heating for industrial heating and drying processes, lava lamps, the Easy-Bake Oven toy. Incandescent bulbs have short lifetimes compared with other types of lighting. Incandescent bulbs have been replaced in many applications by other types of electric light, such as fluorescent lamps, compact fluorescent lamps, cold cathode fluorescent lamps, high-intensity discharge lamps, light-emitting diode lamps; some jurisdictions, such as the European Union, China and United States, are in the process of phasing out the use of incandescent light bulbs while others, including Colombia, Cuba and Brazil, have prohibited them already.
In addressing the question of who invented the incandescent lamp, historians Robert Friedel and Paul Israel list 22 inventors of incandescent lamps prior to Joseph Swan and Thomas Edison. They conclude that Edison's version was able to outstrip the others because of a combination of three factors: an effective incandescent material, a higher vacuum than others were able to achieve and a high resistance that made power distribution from a centralized source economically viable. Historian Thomas Hughes has attributed Edison's success to his development of an entire, integrated system of electric lighting; the lamp was a small component in his system of electric lighting, no more critical to its effective functioning than the Edison Jumbo generator, the Edison main and feeder, the parallel-distribution system. Other inventors with generators and incandescent lamps, with comparable ingenuity and excellence, have long been forgotten because their creators did not preside over their introduction in a system of lighting.
In 1761 Ebenezer Kinnersley demonstrated heating a wire to incandescence. In 1802, Humphry Davy used what he described as "a battery of immense size", consisting of 2,000 cells housed in the basement of the Royal Institution of Great Britain, to create an incandescent light by passing the current through a thin strip of platinum, chosen because the metal had an high melting point, it was not bright enough nor did it last long enough to be practical, but it was the precedent behind the efforts of scores of experimenters over the next 75 years. Over the first three-quarters of the 19th century, many experimenters worked with various combinations of platinum or iridium wires, carbon rods, evacuated or semi-evacuated enclosures. Many of these devices were demonstrated and some were patented. In 1835, James Bowman Lindsay demonstrated a constant electric light at a public meeting in Dundee, Scotland, he stated that he could "read a book at a distance of one and a half feet". Lindsay, a lecturer at the Watt Institution in Dundee, Scotland, at the time, had developed a light, not combustible, created no smoke or smell and was less expensive to produce than Davy's platinum-dependent bulb.
However, having perfected the device to his own satisfaction, he turned to the problem of wireless telegraphy and did not develop the electric light any further. His claims are not well documented, although he is credited in Challoner et al. with being the inventor of the "Incandescent Light Bulb". In 1838, Belgian lithographer Marcellin Jobard invented an incandescent light bulb with a vacuum atmosphere using a carbon filament. In 1840, British scientist Warren de la Rue enclosed a coiled platinum filament in a vacuum tube and passed an electric current through it; the design was based on the concept that the high melting point of platinum would allow it to operate at high temperatures and that the evacuated chamber would contain fewer gas molecules to react with the platinum, improving its longevity. Although a workable design, the cost of the platinum made it impractical for commercial use. In 1841, Frederick de Moleyns of England was granted the first patent for an incandescent lamp, with a design using platinum wires contained within a vacuum
Nitrocellulose is a flammable compound formed by nitrating cellulose through exposure to nitric acid or another powerful nitrating agent. When used as a propellant or low-order explosive, it was known as guncotton. Nitrated cellulose has found uses as a plastic film and in inks and wood coatings. In 1862, the first man-made plastic, was created by Alexander Parkes from cellulose treated with nitric acid and a solvent. In 1868, American inventor John Wesley Hyatt developed a plastic material he named Celluloid, improving on Parkes' invention by plasticizing the nitrocellulose with camphor so it could be processed into finished form and used as a photographic film. Celluloid was used by Kodak, other suppliers, from the late 1880s as a film base in photography, X-ray films, motion-picture films, was known as nitrate film. After numerous fires caused by unstable nitrate films, "safety film" started to be used from the 1930s in the case of X-ray stock and from 1948 for motion-picture film. Henri Braconnot discovered in 1832 that nitric acid, when combined with starch or wood fibers, would produce a lightweight combustible explosive material, which he named xyloïdine.
A few years in 1838, another French chemist, Théophile-Jules Pelouze, treated paper and cardboard in the same way. Jean-Baptiste Dumas obtained a similar material; these substances were unstable and were not practical explosives. However, around 1846 Christian Friedrich Schönbein, a German-Swiss chemist, discovered a more practical solution; as he was working in the kitchen of his home in Basel, he spilled a mixture of nitric acid and sulfuric acid on the kitchen table. He reached for the nearest cloth, a cotton apron, wiped it up, he hung the apron on the stove door to dry, as soon as it was dry, a flash occurred as the apron ignited. His preparation method was the first to be imitated—one part of fine cotton wool to be immersed in 15 parts of an equal blend of sulfuric and nitric acids. After two minutes, the cotton was removed and washed in cold water to set the esterification level and remove all acid residue, it was slowly dried at a temperature below 40 °C. Schönbein collaborated with the Frankfurt professor Rudolf Christian Böttger, who had discovered the process independently in the same year.
By coincidence, a third chemist, the Brunswick professor F. J. Otto had produced guncotton in 1846 and was the first to publish the process, much to the disappointment of Schönbein and Böttger; the process uses nitric acid to convert cellulose into cellulose nitrate and water: 3 HNO3+ C6H10O5 H2SO4→ C6H73O5 + 3 H2OThe sulfuric acid is present as a catalyst to produce the nitronium ion, NO+2. The reaction is first order and proceeds by electrophilic substitution at the C−OH centers of the cellulose. Guncotton is made by treating cotton with concentrated sulfuric acid and 70% nitric acid cooled to 0 °C to produce cellulose trinitrate. While guncotton is dangerous to store, the hazards it presents can be reduced by storing it dampened with various liquids, such as alcohol. For this reason, accounts of guncotton usage dating from the early 20th century refer to "wet guncotton"; the power of guncotton made it suitable for blasting. As a projectile driver, it had around six times the gas generation of an equal volume of black powder and produced less smoke and less heating.
The patent rights for the manufacture of guncotton were obtained by John Hall & Son in 1846, industrial manufacture of the explosive began at a purpose-built factory at Marsh Works in Faversham, Kent, a year later. However, the manufacturing process was not properly understood and few safety measures were put in place. A serious explosion in July of that year killed two dozen workers, resulting in the immediate closure of the plant. Guncotton manufacture ceased for over 15 years. Further research indicated the importance of careful washing of the acidified cotton. Unwashed nitrocellulose may spontaneously ignite and explode at room temperature, as the evaporation of water results in the concentration of unreacted acid; the British chemist Frederick Augustus Abel developed the first safe process for guncotton manufacture, which he patented in 1865. The washing and drying times of the nitrocellulose were both extended to 48 hours and repeated eight times over; the acid mixture was changed to two parts sulfuric acid to one part nitric.
Nitration can be controlled by adjusting reaction temperature. Nitrocellulose is soluble in a mixture of alcohol and ether until nitrogen concentration exceeds 12%. Soluble nitrocellulose, or a solution thereof, is sometimes called collodion. Guncotton containing more than 13% nitrogen was prepared by prolonged exposure to hot, concentrated acids for limited use as a blasting explosive or for warheads of underwater weapons such as naval mines and torpedoes. Safe and sustained production of guncotton began at the Waltham Abbey Royal Gunpowder Mills in the 1860s, the material became the dominant explosive, becoming the standard for military warheads, although it remained too potent to be used as a propellant. More-stable and slower-burning collodion mixtures were prepared using less-concentrated acids at lower temperatures for smokeless powder in firearms; the first practical smokeless powder made from nitrocellulose, for firearms and artillery ammunition, was invented by French chemist Paul Vieille in 1884.