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137-416: In the immediate post- World War II era, most downhill ski bindings were of the "Kandahar" pattern of cable binding . This consisted of a metal cup at the front of the ski that kept the boot centred, with a leather strap buckled over the toe to hold it down into the cup. A long metal cable or spring ran around the back of the boot, over a flange protruding from the heel. The strap held the boot forward and kept

274-637: A Neutrality Pact in April 1941, and Japan adopted the doctrine of Nanshin-ron , promoted by the Navy, which took its focus southward and eventually led to war with the United States and the Western Allies. In Europe, Germany and Italy were becoming more aggressive. In March 1938, Germany annexed Austria , again provoking little response from other European powers. Encouraged, Hitler began pressing German claims on

411-564: A cautious French probe into the Saarland . The Western Allies also began a naval blockade of Germany , which aimed to damage the country's economy and war effort. Germany responded by ordering U-boat warfare against Allied merchant and warships, which would later escalate into the Battle of the Atlantic . On 8 September, German troops reached the suburbs of Warsaw . The Polish counter-offensive to

548-478: A button directly in front of the toe under the binding arms. When the boot slid forward along the ski, the boot would press on the button which released tension in the binding and made it much easier to release. This was a further improvement on the series of design changes improving the forward release capabilities of the toe. The ultimate evolution was the XM version, which also allowed the toe piece to rotated directly up, as

685-505: A centimetre deep. The system was difficult to install, weakened the ski, and also heavy. Beyl wanted a sexy name for the company, and took one from a US photo magazine . Look was formed in Nevers , France in 1948. The system saw limited sales, but was in use on the French ski team by 1950. Beyl was a perfectionist and was unhappy with his plate design. What he wanted was a lightweight solution that

822-496: A common household product, now offered by hundreds of manufacturers across the world. The brand name Zepel was used for promoting its stain-resistance and water-resistance when applied to fabrics. In the 1990s, it was found that PTFE could be radiation cross-linked above its melting point in an oxygen-free environment. Electron beam processing is one example of radiation processing. Cross-linked PTFE has improved high-temperature mechanical properties and radiation stability. That

959-645: A minimal loss of performance over the lifetime of the gasket. PTFE is an ultraviolet (UV) transparent polymer. However, when exposed to an excimer laser beam it severely degrades due to heterogeneous photothermal effect . Processing PTFE can be difficult and expensive because its high melting temperature, 327 °C (621 °F), is above its decomposition temperature. Even when molten, PTFE does not flow due to its exceedingly high melt-viscosity. The viscosity and melting point can be decreased by inclusion of small amount of comonomers such as perfluoro (propylvinyl ether) and hexafluoropropylene (HFP). These cause

1096-402: A new chlorofluorocarbon refrigerant, called tetrafluoroethylene . The gas in its pressure bottle stopped flowing before the bottle's weight had dropped to the point signaling "empty". John J. Beall (chemist), noticing a weight differential in his test cylinder, brought it to the attention of Roy Plunkett. The chemists in the lab sawed the bottle apart and found the bottle's interior coated with

1233-514: A pretext to initiate the invasion. The first German attack of the war came against the Polish defences at Westerplatte . The United Kingdom responded with an ultimatum for Germany to cease military operations, and on 3 September, after the ultimatum was ignored, Britain and France declared war on Germany. During the Phoney War period, the alliance provided no direct military support to Poland, outside of

1370-765: A pretext to worsen relations. On 29 August, Hitler demanded that a Polish plenipotentiary immediately travel to Berlin to negotiate the handover of Danzig , and to allow a plebiscite in the Polish Corridor in which the German minority would vote on secession. The Poles refused to comply with the German demands, and on the night of 30–31 August in a confrontational meeting with the British ambassador Nevile Henderson , Ribbentrop declared that Germany considered its claims rejected. On 1 September 1939, Germany invaded Poland after having staged several false flag border incidents as

1507-469: A secret protocol that defined German and Soviet "spheres of influence" (western Poland and Lithuania for Germany; eastern Poland , Finland, Estonia , Latvia and Bessarabia for the Soviet Union), and raised the question of continuing Polish independence. The pact neutralised the possibility of Soviet opposition to a campaign against Poland and assured that Germany would not have to face the prospect of

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1644-510: A short, sharp force would pop the binding even when the movement would not have been enough to cause damage to the leg. This allowed the Nevada II to be safely used at much lower tension settings, improving the chances of it releasing when needed while still preventing pre-release. At the same time, Look introduced their Grand Prix heel binding. This was essentially one half of a Nevada system, turned sideways so it released vertically instead of to

1781-743: A similar pact and rejected ceding part of its territory to the Soviet Union. The Soviet Union invaded Finland in November 1939, and was subsequently expelled from the League of Nations for this crime of aggression. Despite overwhelming numerical superiority, Soviet military success during the Winter War was modest, and the Finno-Soviet war ended in March 1940 with some Finnish concessions of territory . In June 1940,

1918-583: A single mass. The most common use of PTFE, consuming about 50% of production, is for the insulation of wiring in aerospace and computer applications (e.g. hookup wire, coaxial cables). This application exploits the fact that PTFE has excellent dielectric properties, specifically low group velocity dispersion , especially at high radio frequencies , making it suitable for use as an excellent insulator in connector assemblies and cables , and in printed circuit boards used at microwave frequencies. Combined with its high melting temperature, this makes PTFE

2055-519: A two-front war, as it had in World War   I. Immediately afterwards, Hitler ordered the attack to proceed on 26 August, but upon hearing that the United Kingdom had concluded a formal mutual assistance pact with Poland and that Italy would maintain neutrality, he decided to delay it. In response to British requests for direct negotiations to avoid war, Germany made demands on Poland, which served as

2192-496: A waxy white material that was oddly slippery. Analysis showed that it was polymerized perfluoroethylene, with the iron from the inside of the container having acted as a catalyst at high pressure. Kinetic Chemicals patented the new fluorinated plastic (analogous to the already known polyethylene ) in 1941, and registered the Teflon trademark in 1945. By 1948, DuPont, which founded Kinetic Chemicals in partnership with General Motors ,

2329-425: Is Because tetrafluoroethylene can explosively decompose to tetrafluoromethane ( CF 4 {\textstyle {\ce {CF4}}} ) and carbon, a special apparatus is required for the polymerization to prevent hot spots that might initiate this dangerous side reaction. The process is typically initiated with persulfate , which homolyzes to generate sulfate radicals: The resulting polymer

2466-407: Is a fluorocarbon solid, as it is a high- molecular-weight polymer consisting wholly of carbon and fluorine . PTFE is hydrophobic : neither water nor water-containing substances wet PTFE, as fluorocarbons exhibit only small London dispersion forces due to the low electric polarizability of fluorine. PTFE has one of the lowest coefficients of friction of any solid. Polytetrafluoroethylene

2603-525: Is a brand of expanded PTFE (ePTFE), a material incorporating a fluoropolymer membrane with micropores. The roof of the Hubert H. Humphrey Metrodome in Minneapolis , US, was one of the largest applications of PTFE coatings. 20 acres (81,000 m ) of the material was used in the creation of the white double-layered PTFE-coated fiberglass dome. Because of its extreme non-reactivity and high temperature rating, PTFE

2740-579: Is considered a minor exposure pathway to PFOA. As a result of the lawsuits concerning the PFOA class-action lawsuit , DuPont began to use GenX, a similarly fluorinated compound, as a replacement for perfluorooctanoic acid in the manufacture of fluoropolymers , such as Teflon-brand PTFE. However, the EPA has classified GenX as more toxic than PFOA and it has proven to be a “regrettable substitute”; its effects may be equally harmful or even more detrimental than those of

2877-822: Is no longer being made in the United States. PTFE was added to the Living Building Challenge (LBC) Red List in 2016. The Red List bans substances prevalent in the building industry that pose serious risks to human health and the environment from construction that seeks to meet the criteria of the Living Building Challenge (LBC). Sodium trifluoroacetate and the similar compound sodium chlorodifluoroacetate can both be generated when PTFE undergoes thermolysis , as well as producing longer chain polyfluoro- and/or polychlorofluoro- (C3-C14) carboxylic acids which may be equally persistent. These products can accumulate in evaporative wetlands and have been found in

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3014-568: Is notable for its extremely low coefficient of friction, its hydrophobia (which serves to inhibit rust), and for the dry film it forms after application, which allows it to resist collecting particles that might otherwise form an abrasive paste. Brands include GT85, Tri-Flow and WD-40 Specialist. PTFE is best known for its use in coating non-stick frying pans and other cookware, as it is hydrophobic and possesses fairly high heat resistance. The sole plates of some clothes irons are coated with PTFE. Other niche applications include: While PTFE

3151-403: Is often used as the liner in hose assemblies, expansion joints , and in industrial pipe lines, particularly in applications using acids, alkalis, or other chemicals. Its frictionless qualities allow improved flow of highly viscous liquids and for uses in applications such as brake hoses. PTFE architectural membranes are created by coating a woven glass-fibre base cloth with PTFE, forming one of

3288-439: Is stable at lower temperatures, it begins to deteriorate at temperatures of about 260 °C (500 °F), it decomposes above 350 °C (662 °F), and pyrolysis occurs at temperatures above 400 °C (752 °F). The main decomposition products are fluorocarbon gases and a sublimate , including tetrafluoroethylene (TFE) and difluorocarbene radicals (RCF2). An animal study conducted in 1955 concluded that it

3425-414: Is terminated with sulfate ester groups, which can be hydrolyzed to give OH end-groups . Granular PTFE is produced via suspension polymerization, where PTFE is suspended in an aqueous medium primarily via agitation and sometimes with the use of a surfactant. PTFE is also synthesized via emulsion polymerization, where a surfactant is the primary means of keeping PTFE in an aqueous medium. Surfactants in

3562-615: Is the case in a backward fall. Various models of the Pivot were Look's primary offering into the 1990s. When Look was purchased in 1994 by Rossignol, they re-branded the Pivot under their own name. Look-branded versions re-appeared in 2009. Throughout its long history, Look's only other major binding design was the Look Integral , which was aimed at ski rental shops. World War II Asia-Pacific Mediterranean and Middle East Other campaigns Coups World War II or

3699-571: Is unlikely that these products would be generated in amounts significant to health at temperatures below 250 °C (482 °F). Above those temperatures the degradation by-products can be lethal to birds , and can cause flu-like symptoms in humans ( polymer fume fever ), although in humans those symptoms disappear within a day or two of being moved to fresh air. Most cases of polymer fume fever in humans occur due to smoking PTFE-contaminated tobacco, although cases have occurred in people who have welded near PTFE components. PTFE-coated cookware

3836-434: Is unlikely to reach dangerous temperatures with normal use, as meat is usually fried between 204 and 232 °C (399 and 450 °F), and most cooking oils (except refined safflower and avocado oils) start to smoke before a temperature of 260 °C (500 °F) is reached. A 1973 study by DuPont's Haskell Laboratory found that a 4-hour exposure to the fumes emitted by PTFE cookware heated to 280 °C (536 °F)

3973-451: Is used as a non-stick coating for pans and other cookware. It is non-reactive, partly because of the strength of carbon–fluorine bonds , so it is often used in containers and pipework for reactive and corrosive chemicals. Where used as a lubricant , PTFE reduces friction, wear, and energy consumption of machinery. It is used as a graft material in surgery and as a coating on catheters . PTFE and chemicals used in its production are some of

4110-500: Is usually measured against polished steel. PTFE's coefficient of friction is 0.05 to 0.10, which is the third-lowest of any known solid material ( aluminium magnesium boride (BAM) being the lowest, with a coefficient of friction of 0.02; diamond-like carbon being second-lowest at 0.05). PTFE's resistance to van der Waals forces means that it is the only known surface to which a gecko cannot stick. In addition, PTFE can be used to prevent insects from climbing up surfaces painted with

4247-588: The Anglo-German Naval Agreement and the German–Polish declaration of non-aggression . The situation became a crisis in late August as German troops continued to mobilise against the Polish border. On 23 August the Soviet Union signed a non-aggression pact with Germany, after tripartite negotiations for a military alliance between France, the United Kingdom, and Soviet Union had stalled. This pact had

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4384-662: The British Empire , with fighting in the Balkans , Mediterranean, and Middle East , the aerial Battle of Britain and the Blitz , and naval Battle of the Atlantic . Through a series of campaigns and treaties, Germany took control of much of continental Europe and formed the Axis alliance with Italy , Japan , and other countries. In June 1941, Germany led the European Axis in an invasion of

4521-566: The German Revolution of 1918–1919 , and a democratic government, later known as the Weimar Republic , was created. The interwar period saw strife between supporters of the new republic and hardline opponents on both the political right and left. Italy, as an Entente ally, had made some post-war territorial gains; however, Italian nationalists were angered that the promises made by the United Kingdom and France to secure Italian entrance into

4658-814: The German invasion of Poland and the United Kingdom and France 's declaration of war on Germany two days later on 3 September 1939. Dates for the beginning of the Pacific War include the start of the Second Sino-Japanese War on 7 July 1937, or the earlier Japanese invasion of Manchuria , on 19 September 1931. Others follow the British historian A. J. P. Taylor , who stated that the Sino-Japanese War and war in Europe and its colonies occurred simultaneously, and

4795-567: The Italian mainland , and Allied offensives in the Pacific—cost the Axis powers their initiative and forced them into strategic retreat on all fronts. In 1944, the Western Allies invaded German-occupied France at Normandy , while the Soviet Union regained its territorial losses and pushed Germany and its allies westward. At the same time, Japan suffered reversals in mainland Asia, while the Allies crippled

4932-537: The Japanese Navy and captured key islands . The war in Europe concluded with the liberation of German-occupied territories ; the invasion of Germany by the Western Allies and the Soviet Union, culminating in the fall of Berlin to Soviet troops; Hitler's suicide ; and the German unconditional surrender on 8 May 1945 . Following the refusal of Japan to surrender on the terms of the Potsdam Declaration ,

5069-682: The League of Nations as a force to preserve peace. Both Italy and Ethiopia were member nations, but the League did little when the former clearly violated Article X of the League's Covenant . The United Kingdom and France supported imposing sanctions on Italy for the invasion, but the sanctions were not fully enforced and failed to end the Italian invasion. Italy subsequently dropped its objections to Germany's goal of absorbing Austria . When civil war broke out in Spain, Hitler and Mussolini lent military support to

5206-693: The Nationalist rebels , led by General Francisco Franco . Italy supported the Nationalists to a greater extent than the Nazis: Mussolini sent more than 70,000 ground troops, 6,000 aviation personnel, and 720 aircraft to Spain. The Soviet Union supported the existing government of the Spanish Republic . More than 30,000 foreign volunteers, known as the International Brigades , also fought against

5343-677: The Rome–Berlin Axis . A month later, Germany and Japan signed the Anti-Comintern Pact , which Italy joined the following year. The Kuomintang (KMT) party in China launched a unification campaign against regional warlords and nominally unified China in the mid-1920s, but was soon embroiled in a civil war against its former Chinese Communist Party (CCP) allies and new regional warlords . In 1931, an increasingly militaristic Empire of Japan , which had long sought influence in China as

5480-603: The Second World War (1 September 1939 – 2 September 1945) was a global conflict between two coalitions: the Allies and the Axis powers . Nearly all the world's countries —including all the great powers —participated, with many investing all available economic, industrial, and scientific capabilities in pursuit of total war , blurring the distinction between military and civilian resources. Tanks and aircraft played major roles , with

5617-581: The Soviet–Japanese Neutrality Pact in April 1941. By contrast, the Germans were steadily making preparations for an attack on the Soviet Union, massing forces on the Soviet border. Hitler believed that the United Kingdom's refusal to end the war was based on the hope that the United States and the Soviet Union would enter the war against Germany sooner or later. On 31 July 1940, Hitler decided that

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5754-580: The Stresa Front in April 1935 in order to contain Germany, a key step towards military globalisation ; however, that June, the United Kingdom made an independent naval agreement with Germany, easing prior restrictions. The Soviet Union, concerned by Germany's goals of capturing vast areas of Eastern Europe , drafted a treaty of mutual assistance with France. Before taking effect, though, the Franco-Soviet pact

5891-689: The Sudetenland , an area of Czechoslovakia with a predominantly ethnic German population. Soon the United Kingdom and France followed the appeasement policy of British Prime Minister Neville Chamberlain and conceded this territory to Germany in the Munich Agreement , which was made against the wishes of the Czechoslovak government, in exchange for a promise of no further territorial demands. Soon afterwards, Germany and Italy forced Czechoslovakia to cede additional territory to Hungary, and Poland annexed

6028-682: The Tanggu Truce was signed in 1933. Thereafter, Chinese volunteer forces continued the resistance to Japanese aggression in Manchuria , and Chahar and Suiyuan . After the 1936 Xi'an Incident , the Kuomintang and CCP forces agreed on a ceasefire to present a united front to oppose Japan. The Second Italo-Ethiopian War was a brief colonial war that began in October 1935 and ended in May 1936. The war began with

6165-568: The Trans-Olza region of Czechoslovakia. Although all of Germany's stated demands had been satisfied by the agreement, privately Hitler was furious that British interference had prevented him from seizing all of Czechoslovakia in one operation. In subsequent speeches Hitler attacked British and Jewish "war-mongers" and in January 1939 secretly ordered a major build-up of the German navy to challenge British naval supremacy. In March 1939, Germany invaded

6302-554: The Treaty of Craiova . The loss of one-third of Romania's 1939 territory caused a coup against King Carol II, turning Romania into a fascist dictatorship under Marshal Ion Antonescu , with a course set towards the Axis in the hopes of a German guarantee. Meanwhile, German-Soviet political relations and economic co-operation gradually stalled, and both states began preparations for war. In April 1940, Germany invaded Denmark and Norway to protect shipments of iron ore from Sweden , which

6439-723: The United Kingdom and France to declare war on Germany. Poland was divided between Germany and the Soviet Union under the Molotov–Ribbentrop Pact , in which they had agreed on " spheres of influence " in Eastern Europe. In 1940, the Soviets annexed the Baltic states and parts of Finland and Romania . After the fall of France in June 1940, the war continued mainly between Germany and

6576-683: The Wehrmacht rapidly advanced to the Channel and cut off the Allied forces in Belgium, trapping the bulk of the Allied armies in a cauldron on the Franco-Belgian border near Lille. The United Kingdom was able to evacuate a significant number of Allied troops from the continent by early June, although they had to abandon almost all their equipment. On 10 June, Italy invaded France , declaring war on both France and

6713-612: The aftermath of World War I and the rise of fascism in Europe and militarism in Japan . Key events leading up to the war included Japan's invasion of Manchuria , the Spanish Civil War , the outbreak of the Second Sino-Japanese War , and Germany's annexations of Austria and the Sudetenland . World War II is generally considered to have begun on 1 September 1939, when Nazi Germany , under Adolf Hitler , invaded Poland , prompting

6850-460: The electrostatic analogues of permanent magnets . PTFE film is also widely used in the production of carbon fiber composites as well as fiberglass composites, notably in the aerospace industry. PTFE film is used as a barrier between the carbon or fiberglass part being built and, in breather and bagging materials, is used to incapsulate the bondment when debulking (vacuum removal of air from between layers of laid-up plies of material) and when curing

6987-404: The reunification of East and West Germany to take place and resolved most post–World War   II issues. No formal peace treaty between Japan and the Soviet Union was ever signed, although the state of war between the two countries was terminated by the Soviet–Japanese Joint Declaration of 1956 , which also restored full diplomatic relations between them. World War I had radically altered

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7124-416: The 1950s, Look's only real competitor in Europe was Marker , who introduced their Duplex design in 1952. The Duplex improved on the Nevada by using two clips to hold the toe, rather than a single cup. By locating the clips at the corners of the binding, even falls that created straightforward pressure would cause it to open - the clips would be forced outwards and create sideways forces for the main pivot under

7261-429: The 1990s, PTFE was not known to crosslink like an elastomer , due to its chemical inertness. Therefore, it has no "memory" and is subject to creep . Because of the propensity to creep, the long-term performance of such seals is worse than for elastomers that exhibit zero, or near-zero, levels of creep. In critical applications, Belleville washers are often used to apply continuous force to PTFE gaskets, thereby ensuring

7398-409: The Allies were attempting to cut off . Denmark capitulated after six hours , and despite Allied support , Norway was conquered within two months. British discontent over the Norwegian campaign led to the resignation of Prime Minister Neville Chamberlain , who was replaced by Winston Churchill on 10   May 1940. On the same day, Germany launched an offensive against France . To circumvent

7535-400: The Axis war against the Soviet Union, in Romania's case partially to recapture territory ceded to the Soviet Union . In early June 1940, the Italian Regia Aeronautica attacked and besieged Malta , a British possession. From late summer to early autumn, Italy conquered British Somaliland and made an incursion into British-held Egypt . In October, Italy attacked Greece , but the attack

7672-421: The Blitz , but largely ended in May 1941 after failing to significantly disrupt the British war effort. Using newly captured French ports, the German Navy enjoyed success against an over-extended Royal Navy , using U-boats against British shipping in the Atlantic . The British Home Fleet scored a significant victory on 27   May 1941 by sinking the German battleship Bismarck . In November 1939,

7809-405: The European Axis declaring war on the US. Japan conquered much of coastal China and Southeast Asia , but its advances in the Pacific were halted in mid-1942 after its defeat in the naval Battle of Midway ; Germany and Italy were defeated in North Africa and at Stalingrad in the Soviet Union. Key setbacks in 1943—including German defeats on the Eastern Front, the Allied invasions of Sicily and

7946-470: The French engineer Marc Grégoire, to try the material he had been using on fishing tackle on her cooking pans. He subsequently created the first PTFE-coated, non-stick pans under the brand name Tefal (combining "Tef" from "Teflon" and "al" from aluminium). In the United States, Marion A. Trozzolo , who had been using the substance on scientific utensils, marketed the first US-made PTFE-coated pan, "The Happy Pan", in 1961. Non-stick cookware has since become

8083-410: The French possessions of Syria and Lebanon , assisted by the Free French . With the situation in Europe and Asia relatively stable, Germany, Japan, and the Soviet Union made preparations for war. With the Soviets wary of mounting tensions with Germany, and the Japanese planning to take advantage of the European War by seizing resource-rich European possessions in Southeast Asia , the two powers signed

8220-426: The Germans, and the last large operational unit of the Polish Army surrendered on 6   October . Despite the military defeat, Poland never surrendered; instead, it formed the Polish government-in-exile and a clandestine state apparatus remained in occupied Poland. A significant part of Polish military personnel evacuated to Romania and Latvia; many of them later fought against the Axis in other theatres of

8357-450: The Nationalists. Both Germany and the Soviet Union used this proxy war as an opportunity to test in combat their most advanced weapons and tactics. The Nationalists won the civil war in April 1939; Franco, now dictator, remained officially neutral during World War   II but generally favoured the Axis . His greatest collaboration with Germany was the sending of volunteers to fight on the Eastern Front . In July 1937, Japan captured

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8494-452: The Royal Navy putting three Italian battleships out of commission after a carrier attack at Taranto , and neutralising several more warships at the Battle of Cape Matapan . Italian defeats prompted Germany to deploy an expeditionary force to North Africa; at the end of March 1941, Rommel 's Afrika Korps launched an offensive which drove back Commonwealth forces. In less than a month, Axis forces advanced to western Egypt and besieged

8631-423: The Soviet Union occupied the entire territories of Estonia, Latvia and Lithuania, as well as the Romanian regions of Bessarabia, Northern Bukovina, and the Hertsa region . In August 1940, Hitler imposed the Second Vienna Award on Romania which led to the transfer of Northern Transylvania to Hungary. In September 1940, Bulgaria demanded Southern Dobruja from Romania with German and Italian support, leading to

8768-421: The Soviet Union , opening the Eastern Front and initially making large territorial gains. Japan aimed to dominate East Asia and the Asia-Pacific , and by 1937 was at war with the Republic of China . In December 1941, Japan attacked American and British territories in Southeast Asia and the Central Pacific , including Pearl Harbor in Hawaii , which resulted in the US and the UK declaring war against Japan, and

8905-418: The Soviet Union and Mongolia . The Japanese doctrine of Hokushin-ron , which emphasised Japan's expansion northward, was favoured by the Imperial Army during this time. This policy would prove difficult to maintain in light of the Japanese defeat at Khalkin Gol in 1939, the ongoing Second Sino-Japanese War and ally Nazi Germany pursuing neutrality with the Soviets. Japan and the Soviet Union eventually signed

9042-575: The Soviet Union should be eliminated and aimed for the conquest of Ukraine , the Baltic states and Byelorussia . However, other senior German officials like Ribbentrop saw an opportunity to create a Euro-Asian bloc against the British Empire by inviting the Soviet Union into the Tripartite Pact. In November 1940, negotiations took place to determine if the Soviet Union would join the pact. The Soviets showed some interest but asked for concessions from Finland, Bulgaria, Turkey, and Japan that Germany considered unacceptable. On 18 December 1940, Hitler issued

9179-402: The US dropped the first atomic bombs on Hiroshima and Nagasaki on 6 and 9 August. Faced with an imminent invasion of the Japanese archipelago , the possibility of further atomic bombings, and the Soviet declaration of war against Japan and its invasion of Manchuria , Japan announced its unconditional surrender on 15 August and signed a surrender document on 2 September 1945 , marking

9316-424: The United Kingdom and France guaranteed their support for Polish independence ; when Italy conquered Albania in April 1939, the same guarantee was extended to the Kingdoms of Romania and Greece . Shortly after the Franco - British pledge to Poland, Germany and Italy formalised their own alliance with the Pact of Steel . Hitler accused the United Kingdom and Poland of trying to "encircle" Germany and renounced

9453-489: The United Kingdom attacked on 3   July in an attempt to prevent its seizure by Germany. The air Battle of Britain began in early July with Luftwaffe attacks on shipping and harbours . The German campaign for air superiority started in August but its failure to defeat RAF Fighter Command forced the indefinite postponement of the proposed German invasion of Britain . The German strategic bombing offensive intensified with night attacks on London and other cities in

9590-401: The United Kingdom. The Germans turned south against the weakened French army, and Paris fell to them on 14   June. Eight days later France signed an armistice with Germany ; it was divided into German and Italian occupation zones , and an unoccupied rump state under the Vichy Regime , which, though officially neutral, was generally aligned with Germany. France kept its fleet, which

9727-473: The United States was assisting China and the Western Allies, and had amended the Neutrality Act to allow "cash and carry" purchases by the Allies. In 1940, following the German capture of Paris, the size of the United States Navy was significantly increased . In September the United States further agreed to a trade of American destroyers for British bases . Still, a large majority of the American public continued to oppose any direct military intervention in

9864-590: The Yellow River ; this manoeuvre bought time for the Chinese to prepare their defences at Wuhan , but the city was taken by October. Japanese military victories did not bring about the collapse of Chinese resistance that Japan had hoped to achieve; instead, the Chinese government relocated inland to Chongqing and continued the war. In the mid-to-late 1930s, Japanese forces in Manchukuo had sporadic border clashes with

10001-645: The aggregate effect of carbon-fluorine bonds , as do all fluorocarbons. The only chemicals known to affect these carbon-fluorine bonds are highly reactive metals like the alkali metals , at higher temperatures such metals as aluminium and magnesium, and fluorinating agents such as xenon difluoride and cobalt(III) fluoride . At temperatures above 650–700 °C (1,200–1,290 °F) PTFE undergoes depolymerization. However, it begins to decompose at about 260 °C (500 °F) through 350 °C (662 °F), and pyrolysis occurs at temperatures above 400 °C (752 °F). The coefficient of friction of plastics

10138-617: The area beginning in 1976 with the production of Nafion, and that PFAS including GenX had been released as a byproduct of the production of Vinyl Ethers since 1980, exposing the Cape Fear Basin for decades. A small nonprofit called Cape Fear River Watch sued NC DEQ for not taking swifter and stronger action, and sued the polluter, Chemours, for violations of the Clean Water Act and the Toxic Substances Control Act. The result

10275-534: The best-known and widely applied PFAS , which are persistent organic pollutants . PTFE occupies more than half of all fluoropolymer production, followed by polyvinylidene fluoride (PVdF) . For decades, DuPont used perfluorooctanoic acid (PFOA, or C8) during production of PTFE, later discontinuing its use due to legal actions over ecotoxicological and the health effects of exposure to PFOA . Dupont's spin-off Chemours today manufactures PTFE using an alternative chemical it calls GenX , another PFAS. Although GenX

10412-428: The binding as before, but replaced the rotating cup with two longer fingers. The action to the original Marker Duplex design. However, the use of the two fingers had two effects, for one it allowed a much wider range of boot shapes to be accommodated, and for another, it allowed the boot to travel much further within the binding before it would release. Other bindings with shorter travel were subject to "pre-release", where

10549-675: The binding. In 1953 was replaced in production by the Simplex, which used a single cup like the Nevada, but retained the action of the Duplex and allowed straightforward release. Look and Marker competed for the majority of the European market through the 1950s and into the early 1960s. In 1962 Look dramatically updated their line with the introduction of the Nevada II . The new design used a single pivot point under

10686-461: The blood of people who work in or live near factories where the chemical is used, and in people regularly exposed to PFOA-containing products such as some ski waxes and stain-resistant fabric coatings, but non-stick cookware was not found to be a major source of exposure, as the PFOA is burned off during the manufacturing process and not present in the finished product. Non-stick coated cookware has not been manufactured using PFOA since 2013, and PFOA

10823-410: The boot to exit. However, if the force was also to the front, as in the case of the ski tip catching a tree root or front of a mogul , the pivot would be too close to the line of motion to allow easy rotation. To address this, the entire body of the binding was also pivoted. In this sort of release scenario, the binding as a whole would rotate, and eventually the force would be far enough to the side that

10960-403: The cable was clipped down this was a serious concern. In the 1950s it was estimated that a skier had a 1% chance of suffering an injury on any given day, and that 10% of skiers would suffer a fracture over a single season. In the immediate post-war era there were a few halting attempts to address this problem. However, most suffered from the problem that the leather ski boots wore down quickly and

11097-507: The capital Nanking in December 1937. After the fall of Nanking, tens or hundreds of thousands of Chinese civilians and disarmed combatants were murdered by the Japanese . In March 1938, Nationalist Chinese forces won their first major victory at Taierzhuang , but then the city of Xuzhou was taken by the Japanese in May. In June 1938, Chinese forces stalled the Japanese advance by flooding

11234-428: The case of an accident. In particular, if the forward tip of the ski rotated to the side, the force was transmitted through the length of the ski to the boot, forming a huge moment arm . Even small forces could produce torques able to break the ankle or knee, and spiral fractures of the calf were common. This was not as much of an issue in cross-country where the heel was relatively free to move, but in downhill use when

11371-627: The chemical it was meant to replace. The chemicals are manufactured by Chemours , a corporate spin-off of DuPont, in Fayetteville, North Carolina . Fayetteville Works was the site where DuPont began manufacture of PFOA after the lawsuit in Parkersburg WV halted their production there. When EPA asked companies to voluntarily phase out PFOA production, it was replaced by GenX in Fayetteville Works. In June of 2017, The Wilmington Star-News broke

11508-498: The clip would be forced sideways. As before, Beyl wanted a US-sounding name for his new binding, and selected "Nevada". The binding was released in 1950, along with a Nevada-branded cable binding of conventional design. The Nevada toe was the first modern ski binding that worked safely with any unmodified boot, eschewing attempts to attach to the sole or use add-on plates or clips. The basic two-pivot design has become universal, and used with only minor modifications to this day. Through

11645-424: The composite, usually in an autoclave. The PTFE, used here as a film, prevents the non-production materials from sticking to the part being built, which is sticky due to the carbon-graphite or fiberglass plies being pre-pregnated with bismaleimide resin. Non-production materials such as Teflon, Airweave Breather, and the bag itself would be considered F.O.D. (foreign object debris/damage) if left in layup. Gore-Tex

11782-403: The conflict well into 1941. In December 1940, Roosevelt accused Hitler of planning world conquest and ruled out any negotiations as useless, calling for the United States to become an " arsenal of democracy " and promoting Lend-Lease programmes of military and humanitarian aid to support the British war effort; Lend-Lease was later extended to the other Allies, including the Soviet Union after it

11919-515: The creation of a " New Roman Empire ". Adolf Hitler , after an unsuccessful attempt to overthrow the German government in 1923, eventually became the Chancellor of Germany in 1933 when Paul von Hindenburg and the Reichstag appointed him. Following Hindenburg's death in 1934, Hitler proclaimed himself Führer of Germany and abolished democracy, espousing a radical, racially motivated revision of

12056-428: The directive to prepare for an invasion of the Soviet Union. Teflon Polytetrafluoroethylene ( PTFE ) is a synthetic fluoropolymer of tetrafluoroethylene , and has numerous applications because it is chemically inert . The commonly known brand name of PTFE-based composition is Teflon by Chemours , a spin-off from DuPont , which originally discovered the compound in 1938. Polytetrafluoroethylene

12193-739: The dissolution of the Austro-Hungarian, Ottoman, and Russian Empires. To prevent a future world war, the League of Nations was established in 1920 by the Paris Peace Conference . The organisation's primary goals were to prevent armed conflict through collective security, military, and naval disarmament , as well as settling international disputes through peaceful negotiations and arbitration. Despite strong pacifist sentiment after World War   I , irredentist and revanchist nationalism had emerged in several European states. These sentiments were especially marked in Germany because of

12330-637: The end of May completed the German conquest of the Balkans. Partisan warfare subsequently broke out against the Axis occupation of Yugoslavia , which continued until the end of the war. In the Middle East in May, Commonwealth forces quashed an uprising in Iraq which had been supported by German aircraft from bases within Vichy-controlled Syria . Between June and July, British-led forces invaded and occupied

12467-600: The end of the production and phase out of PFOA and PFOS in the US. The general population has been exposed to PFOA through massive dumping of C8 waste into the ocean and near the Ohio River Valley. PFOA has been detected in industrial waste, stain-resistant carpets, carpet cleaning liquids, house dust , microwave popcorn bags , water, food and PTFE cookware. As a result of a class-action lawsuit and community settlement with DuPont , three epidemiologists conducted studies on

12604-508: The end of the war. World War II changed the political alignment and social structure of the world, and it set the foundation of international relations for the rest of the 20th century and into the 21st century. The United Nations was established to foster international cooperation and prevent conflicts, with the victorious great powers—China, France, the Soviet Union, the UK, and the US—becoming

12741-400: The first attempts to solve the twisting fall problem. His design pivoted around a bearing under the foot, in order to ensure that torque did not built up to dangerous levels. Although it did not release the boot from the ski, it did release the force from the boot. To mount it, the boot was fastened to a metal plate, which was in turn cut into the upper surface of the ski in a mortise joint about

12878-566: The first step of what its government saw as the country's right to rule Asia , staged the Mukden incident as a pretext to invade Manchuria and establish the puppet state of Manchukuo . China appealed to the League of Nations to stop the Japanese invasion of Manchuria. Japan withdrew from the League of Nations after being condemned for its incursion into Manchuria. The two nations then fought several battles, in Shanghai , Rehe and Hebei , until

13015-843: The former Chinese imperial capital of Peking after instigating the Marco Polo Bridge incident , which culminated in the Japanese campaign to invade all of China. The Soviets quickly signed a non-aggression pact with China to lend materiel support, effectively ending China's prior cooperation with Germany . From September to November, the Japanese attacked Taiyuan , engaged the Kuomintang Army around Xinkou , and fought Communist forces in Pingxingguan . Generalissimo Chiang Kai-shek deployed his best army to defend Shanghai , but after three months of fighting, Shanghai fell. The Japanese continued to push Chinese forces back, capturing

13152-418: The general US population in the low and sub- parts per billion range, and levels are higher in chemical plant employees and surrounding subpopulations. PFOA and perfluorooctanesulfonic acid (PFOS) have been estimated to be in every American person's blood stream in the parts per billion range, though those concentrations have decreased by 70% for PFOA and 84% for PFOS between 1999 and 2014, which coincides with

13289-466: The heel of the boot, known as the "turntable", which stopped the boot from jamming on the heel release's arms when the toe was releasing to the side. These improvements were released as the Look Nevada N17 in the late 1960s. The name now referred to both the toe and heel release as a pair, the separate Grand Prix name was dropped. The N17 was replaced by the similar N57 and N77 from the mid-1970s, which

13426-406: The industry. In addition to a pad on top of the ski under the toe, Look also added a second smaller pad where the very front of the boot pressed under the Nevada's toe clips. The pad was shaped to force the boot sideways in the event of a forward fall, further adding to the forces trying to release the toe. This basic Grand Prix system was later improved with the addition of a rotating platform under

13563-512: The invasion of the Ethiopian Empire (also known as Abyssinia ) by the armed forces of the Kingdom of Italy ( Regno d'Italia ), which was launched from Italian Somaliland and Eritrea . The war resulted in the military occupation of Ethiopia and its annexation into the newly created colony of Italian East Africa ( Africa Orientale Italiana , or AOI); in addition it exposed the weakness of

13700-677: The latter enabling the strategic bombing of population centres and delivery of the only two nuclear weapons ever used in war. World War II was the deadliest conflict in history, resulting in 70 to 85 million deaths , more than half being civilians. Millions died in genocides , including the Holocaust of European Jews, as well as from massacres, starvation, and disease. Following the Allied powers' victory, Germany , Austria , Japan , and Korea were occupied, and war crimes tribunals were conducted against German and Japanese leaders . The causes of World War II included unresolved tensions in

13837-514: The material of choice as a high-performance substitute for the weaker, higher dispersion and lower-melting-point polyethylene commonly used in low-cost applications. In industrial applications, owing to its low friction, PTFE is used for plain bearings , gears , slide plates , seals, gaskets, bushings, and more applications with sliding action of parts, where it outperforms acetal and nylon . Its extremely high bulk resistivity makes it an ideal material for fabricating long-life electrets ,

13974-411: The material. For example, PTFE is used to prevent ants from climbing out of formicaria . There are surface treatments for PTFE that alter the surface to allow adhesion to other materials. Because of its chemical and thermal properties, PTFE is often used as a gasket material within industries that require resistance to aggressive chemicals such as pharmaceuticals or chemical processing. However, until

14111-559: The mounting point between the binding and boot was thus subject to constant change. Some designs address this by having the user screw metal fixings onto the boot sole to provide a more solid mounting point, but these would only fit a single style of binding. In any event, they required constant adjustment and were often complex. Richard Spademan, inventor of the Spademan binding , would later dismissing them all, stating "Bindings were trash." French sporting goods manufacturer Jean Beyl made one of

14248-548: The original Nevada). These had the disadvantage of requiring careful adjustment to fit the height of the toe flange, and could be impacted if snow on the bottom of the heel lifted the toe upward. Today the Nevada-style "two finger toe" is universal among modern bindings. The N77, in turn, gave rise to the 89 and 99, a series of bindings for different skill levels, collectively referred to as the Look Pivot . The Pivot also introduced

14385-424: The otherwise perfectly linear PTFE chain to become branched, reducing its crystallinity. Some PTFE parts are made by cold-moulding, a form of compression molding . Here, fine powdered PTFE is forced into a mould under high pressure (10–100 MPa). After a settling period, lasting from minutes to days, the mould is heated at 360 to 380 °C (680 to 716 °F), allowing the fine particles to fuse ( sinter ) into

14522-661: The past have included toxic perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). More recently, Perfluoro 3,6 dioxaoctanoic acid (PFO2OA) and FRD-903 (GenX) are being used as alternative surfactants. PTFE is a thermoplastic polymer , which is a white solid at room temperature, with a density of about 2200 kg/m and a melting point of 600 K (327 °C; 620 °F). It maintains high strength, toughness and self-lubrication at low temperatures down to 5 K (−268.2 °C; −450.7 °F), and good flexibility at temperatures above 194 K (−79.15 °C; −110.5 °F). PTFE gains its properties from

14659-497: The permanent members of its security council . The Soviet Union and the United States emerged as rival superpowers , setting the stage for the 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 recovery and expansion . World War II began in Europe on 1 September 1939 with

14796-571: The political European map with the defeat of the Central Powers —including Austria-Hungary , Germany , Bulgaria , and the Ottoman Empire —and the 1917 Bolshevik seizure of power in Russia , which led to the founding of the Soviet Union. Meanwhile, the victorious Allies of World War I , such as France, Belgium, Italy, Romania, and Greece, gained territory, and new nation-states were created out of

14933-500: The population of Parkersburg, WV surrounding the (former DuPont) Chemours Washington Works chemical plant that was exposed to PFOA at levels greater than in the general population. The studies concluded that there was an association between PFOA exposure and six health outcomes: kidney cancer , testicular cancer , ulcerative colitis , thyroid disease , hypercholesterolemia (high cholesterol), and gestational hypertension (pregnancy-induced high blood pressure). Overall, PTFE cookware

15070-583: The port of Tobruk . By late March 1941, Bulgaria and Yugoslavia signed the Tripartite Pact ; however, the Yugoslav government was overthrown two days later by pro-British nationalists. Germany and Italy responded with simultaneous invasions of both Yugoslavia and Greece , commencing on 6 April 1941; both nations were forced to surrender within the month. The airborne invasion of the Greek island of Crete at

15207-693: The remainder of Czechoslovakia and subsequently split it into the German Protectorate of Bohemia and Moravia and a pro-German client state , the Slovak Republic . Hitler also delivered an ultimatum to Lithuania on 20 March 1939, forcing the concession of the Klaipėda Region , formerly the German Memelland . Greatly alarmed and with Hitler making further demands on the Free City of Danzig ,

15344-427: The roots and seeds of wetland plant species, but has not been observed to have an adverse impact on plant health or germination success. Perfluorooctanoic acid (PFOA, or C8) has been used as a surfactant in the emulsion polymerization of PTFE, although several manufacturers have entirely discontinued its use. PFOA persists indefinitely in the environment. PFOA has been detected in the blood of many individuals of

15481-498: The sides. With cable bindings the heel was normally held down by looping the cable over the heel or cupped it in a semi-circular indentation on the back of the heel. To fit these different styles of binding points, and the fact that the boots had no standardized size or shape, the rotating portion of the Grand Prix was mounted on a bracket that lifted it above the heel flange, allowing the user to adjust its height. The actual binding point

15618-410: The significant territorial, colonial, and financial losses imposed by the Treaty of Versailles . Under the treaty, Germany lost around 13 percent of its home territory and all its overseas possessions , while German annexation of other states was prohibited, reparations were imposed, and limits were placed on the size and capability of the country's armed forces . The German Empire was dissolved in

15755-471: The skier's leg. During this motion the roller would catch the sole of the boot and lock it into position. Like the Nevada toe, a strong force rotating the boot, this time forward, would cause the binding to release. As the value of low-friction devices to aid boot release became clear in the late 1960s, Look modified the Nevada II into the Nevada T to take advantage of the teflon pads that were becoming common in

15892-494: The start or prelude to World War II. The exact date of the war's end also is not universally agreed upon. It was generally accepted at the time that the war ended with the armistice of 15 August 1945 ( V-J Day ), rather than with the formal surrender of Japan on 2 September 1945, which officially ended the war in Asia . A peace treaty between Japan and the Allies was signed in 1951. A 1990 treaty regarding Germany's future allowed

16029-586: The story that GenX was found in the Cape Fear River – the drinking water supply for 500,000 people. The source of the pollution was determined to be the Fayetteville Works site, which had been run by DuPont since its founding in 1971 and then managed by DuPont spinoff, The Chemours Company, since 2015. The water utility confirmed they had no ability to filter these chemicals from the drinking water. The North Carolina Department of Environmental Quality (NC DEQ) records indicate that DuPont started release PFAS into

16166-575: The strong Maginot Line fortifications on the Franco-German border, Germany directed its attack at the neutral nations of Belgium , the Netherlands , and Luxembourg . The Germans carried out a flanking manoeuvre through the Ardennes region, which was mistakenly perceived by the Allies as an impenetrable natural barrier against armoured vehicles. By successfully implementing new Blitzkrieg tactics,

16303-705: The strongest and most durable materials used in tensile structures . Some notable structures featuring PTFE-tensioned membranes include The O2 Arena in London, Moses Mabhida Stadium in South Africa, Metropolitano Stadium in Spain and the Sydney Football Stadium Roof in Australia. PTFE is often found in musical instrument lubrication products, most commonly valve oil. PTFE is used in some aerosol lubricant sprays, including in micronized and polarized form. It

16440-413: The toe in the cup and under the strap. The system was designed to keep the toe firmly in place while allowing the heel to rise off the ski. This allowed for a smooth cross-country striding motion. For downhill use, the cable was clipped down near the heel to keep the boot in firmer contact with the ski, and allow some level of lateral control. The major problem with these bindings is they did not release in

16577-510: The two wars became World War II in 1941. Other proposed starting dates 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 forces of Mongolia and the Soviet Union from May to September 1939. Others view the Spanish Civil War as

16714-504: The war were not fulfilled in the peace settlement. From 1922 to 1925, the Fascist movement led by Benito Mussolini seized power in Italy with a nationalist, totalitarian , and class collaborationist agenda that abolished representative democracy, repressed socialist, left-wing, and liberal forces, and pursued an aggressive expansionist foreign policy aimed at making Italy a world power, promising

16851-475: The war. Germany annexed western Poland and occupied central Poland ; the Soviet Union annexed eastern Poland ; small shares of Polish territory were transferred to Lithuania and Slovakia . On 6 October, Hitler made a public peace overture to the United Kingdom and France but said that the future of Poland was to be determined exclusively by Germany and the Soviet Union. The proposal was rejected and Hitler ordered an immediate offensive against France, which

16988-503: The west halted the German advance for several days, but it was outflanked and encircled by the Wehrmacht . Remnants of the Polish army broke through to besieged Warsaw . On 17 September 1939, two days after signing a cease-fire with Japan , the Soviet Union invaded Poland under the supposed pretext that the Polish state had ceased to exist. On 27 September, the Warsaw garrison surrendered to

17125-687: The world order , and soon began a massive rearmament campaign . France, seeking to secure its alliance with Italy, allowed Italy a free hand in Ethiopia , which Italy desired as a colonial possession. The situation was aggravated in early 1935 when the Territory of the Saar Basin was legally reunited with Germany, and Hitler repudiated the Treaty of Versailles, accelerated his rearmament programme, and introduced conscription. The United Kingdom, France and Italy formed

17262-614: Was invaded by Germany. The United States started strategic planning to prepare for a full-scale offensive against Germany. At the end of September 1940, the Tripartite Pact formally united Japan, Italy, and Germany as the Axis powers . The Tripartite Pact stipulated that any country—with the exception of the Soviet Union—that attacked any Axis Power would be forced to go to war against all three. The Axis expanded in November 1940 when Hungary , Slovakia , and Romania joined. Romania and Hungary later made major contributions to

17399-465: Was a Consent Order, signed February 25, 2019 by Cape Fear River Watch, NC DEQ, and Chemours. The order has required Chemours to stop wastewater discharge, air emissions, groundwater discharge, sampling and filtration options to well users, and required sampling that proved there were upwards of 300 distinct PFAS compounds being released from Fayetteville Works. The Teflon trade name is also used for other polymers with similar compositions: These retain

17536-468: Was a bronze roller sized to be similar to a standard cable, this could clip on top of the heel, or would fit into the indentation cut into the heel of some boots. The Grand Prix offered step-in convenience; to put the binding on, the skier inserted their toe under the Nevada II, then stepped down at the heel. The sole of their boot would catch a small plate or rod extending from the bottom of the binding, rotating it until it flipped up to lie vertically behind

17673-570: Was designed to be less persistent in the environment compared to PFOA, it has proven to be a “regrettable substitute.” Its effects may be equally harmful or even more detrimental than those of the chemical it was meant to replace. Polytetrafluoroethylene (PTFE) was accidentally discovered in 1938 by Roy J. Plunkett while he was working in Chemours Chambers Works plant in New Jersey for DuPont . A team of Dupont chemists attempted to make

17810-408: Was easier to mount, yet retained the ability to absorb lateral forces. His next design used a C-shaped piece that fit over the toe of the boot, eliminating the plate. The toe of a contemporary ski boot is essentially hemispherical, so the single clip kept the boot centred and, by riding over the top of it, pressed down onto the ski. Under a pure sideways release scenario, the clip would rotate to allow

17947-403: Was improved in a number of minor ways, notably the option of a ski brake just behind the toe binding. The Nevada patents ran out in 1976, a similar models with long-travel toes quickly appeared from other binding manufacturers, starting with Salomon. These replaced earlier designs, which generally used a single cup-shaped piece that fitted over the entire toe flange (as opposed to the toe, as in

18084-423: Was lethal for parakeets , although that was a higher temperature than the 260 °C (500 °F) required for fumes from pyrolyzed butter to be lethal to the birds. Perfluorooctanoic acid (PFOA), a chemical formerly used in the manufacture of PTFE products such as non-stick coated cookware, can be carcinogenic for people who are exposed to it (see Ecotoxicity ). Concerning levels of PFOA have been found in

18221-452: Was postponed until the spring of 1940 due to bad weather. After the outbreak of war in Poland, Stalin threatened Estonia , Latvia , and Lithuania with military invasion, forcing the three Baltic countries to sign pacts allowing the creation of Soviet military bases in these countries; in October 1939, significant Soviet military contingents were moved there. Finland refused to sign

18358-566: Was producing over 910,000 kilograms (2,000,000 lb) of Teflon-brand polytetrafluoroethylene per year in Parkersburg, West Virginia . An early use was in the Manhattan Project as a material to coat valves and seals in the pipes holding highly reactive uranium hexafluoride at the vast K-25 uranium enrichment plant in Oak Ridge, Tennessee . In 1954, Colette Grégoire urged her husband,

18495-761: Was repulsed with heavy Italian casualties; the campaign ended within months with minor territorial changes. To assist Italy and prevent Britain from gaining a foothold, Germany prepared to invade the Balkans, which would threaten Romanian oil fields and strike against British dominance of the Mediterranean. In December 1940, British Empire forces began counter-offensives against Italian forces in Egypt and Italian East Africa . The offensives were successful; by early February 1941, Italy had lost control of eastern Libya, and large numbers of Italian troops had been taken prisoner. The Italian Navy also suffered significant defeats, with

18632-651: Was required to go through the bureaucracy of the League of Nations, which rendered it essentially toothless. The United States, concerned with events in Europe and Asia, passed the Neutrality Act in August of the same year. Hitler defied the Versailles and Locarno Treaties by remilitarising the Rhineland in March 1936, encountering little opposition due to the policy of appeasement . In October 1936, Germany and Italy formed

18769-420: Was significant because, for many years, irradiation at ambient conditions has been used to break down PTFE for recycling. This radiation-induced chain scission allows it to be more easily reground and reused. Corona discharge treatment of the surface to increase the energy and improve adhesion has been reported. PTFE is produced by free-radical polymerization of tetrafluoroethylene . The net equation

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