A two-stroke engine is a type of internal combustion engine which completes a power cycle with two strokes of the piston during only one crankshaft revolution. This is in contrast to a "four-stroke engine", which requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. In a two-stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen with the intake and exhaust functions occurring at the same time. Two-stroke engines have a high power-to-weight ratio, power being available in a narrow range of rotational speeds called the "power band". Compared to four-stroke engines, two-stroke engines have a reduced number of moving parts, so can be more compact and lighter; the first commercial two-stroke engine involving in-cylinder compression is attributed to Scottish engineer Dugald Clerk, who patented his design in 1881. However, unlike most two-stroke engines, his had a separate charging cylinder; the crankcase-scavenged engine, employing the area below the piston as a charging pump, is credited to Englishman Joseph Day.
On 31 December 1879, German inventor Karl Benz produced a two-stroke gas engine, for which he received a patent in 1880 in Germany. The first practical two-stroke engine is attributed to Yorkshireman Alfred Angas Scott, who started producing twin-cylinder water-cooled motorcycles in 1908. Gasoline versions are useful in lightweight or portable applications such as chainsaws and motorcycles. However, when weight and size are not an issue, the cycle's potential for high thermodynamic efficiency makes it ideal for diesel compression ignition engines operating in large, weight-insensitive applications, such as marine propulsion, railway locomotives and electricity generation. In a two-stroke engine, the heat transfer from the engine to the cooling system is less than in a four-stroke, which means that two-stroke engines can be more efficient. Crankcase-compression two-stroke engines, such as common small gasoline-powered engines, are lubricated by a petroil mixture in a total-loss system. Oil is mixed in with their petrol fuel beforehand, in a ratio of around 1:50.
All that oil forms emissions, either by being burned in the engine or as oily droplets in the exhaust. This create more exhaust emissions hydrocarbons, than four-stroke engines of comparable power output; the combined opening time of the intake and exhaust ports in some 2-stroke designs can allow some amount of unburned fuel vapors to exit in the exhaust stream. The high combustion temperatures of small air-cooled engines may give high NOx emissions. Two-stroke petrol engines are preferred when mechanical simplicity, light weight, high power-to-weight ratio are design priorities. With the traditional lubrication technique of mixing oil into the fuel, they have the advantage of working in any orientation, as there is no oil reservoir dependent on gravity. A number of mainstream automobile manufacturers have used two-stroke engines in the past, including the Swedish Saab and German manufacturers DKW, Auto-Union, VEB Sachsenring Automobilwerke Zwickau, VEB Automobilwerk Eisenach and VEB Fahrzeug- und Jagdwaffenwerk „Ernst Thälmann.
The Japanese manufacturers Suzuki and Subaru did the same in the 1970s. Production of two-stroke cars ended in the 1980s in the West, due to stringent regulation of air pollution. Eastern Bloc countries continued with the Trabant and Wartburg in East Germany. Two-stroke engines are still found in a variety of small propulsion applications, such as outboard motors, high-performance, small-capacity motorcycles and dirt bikes, scooters, tuk-tuks, karts, ultralight airplanes, model airplanes and other model vehicles, they are common in power tools used outdoors, such as lawn mowers and weed-wackers. With direct fuel injection and a sump-based lubrication system, a two-stroke engine produces air pollution no worse than a four-stroke, it can achieve higher thermodynamic efficiency. Therefore, the cycle has also been used in large diesel engines large industrial and marine engines, as well as some trucks and heavy machinery. There are several experimental designs intended for automobile use: for instance, Lotus of Norfolk, UK, had in 2008 a prototype direct-injection two-stroke engine intended for alcohol fuels called the Omnivore which it is demonstrating in a version of the Exige.
Although the principles remain the same, the mechanical details of various two-stroke engines differ depending on the type. The design types vary according to the method of introducing the charge to the cylinder, the method of scavenging the cylinder and the method of exhausting the cylinder. Piston port is the most common in small two-stroke engines. All functions are controlled by the piston covering and uncovering the ports as it moves up and down in the cylinder. In the 1970s, Yamaha worked out some basic principles for this system, they found that, in general, widening an exhaust port increases the power by the same amount as raising the port, but the power band does not narrow as it does when the port is raised. However, there is a mechanical limit to the width of a single exhaust port, at about 62% of the bore diameter for reasonable ring life. Beyond this, the rings will wear quickly. A maximum 70 % of bore width is possible in racing engines. Intake duration is between 160 degrees. Transfer port ti
Ko Samui is an island off the east coast of Thailand. Geographically in the Chumphon Archipelago, it is part of Surat Thani Province, though as of 2012, Ko Samui was granted municipal status and thus is now locally self-governing. Ko Samui, with an area of 228.7 km2, is Thailand's third largest island after Ko Chang. In 2018, it was visited by 2.7 million tourists. The island was first inhabited about 15 centuries ago, settled by fishermen from the Malay Peninsula and southern China, it appears on Chinese maps dating back under the name Pulo Cornam. The origin of the name samui is unknown, it may come from the Sanskrit-Tamil word สมวย, meaning'sea weather'. Or it may derive from the name of a tree known locally in southern Thailand as ต้นหมุย. A third possibility is. In Hainanese Chinese, เซ่าบ่วย means'first island','barrier', or'gate', or literally'beautiful beach'; as it was their first port of call in Thailand, it became its name and evolved over time to สมุย. Some people believe that the word "samui" derives from the Malay word saboey, or'safe haven'.
There is no firm corroboration of any of these theories. Ko is the Thai word for "island"; until the late-20th century, Ko Samui was an isolated self-sufficient community, having little connection with the mainland of Thailand. The island was without roads until the early 1970s, the 15 km journey from one side of the island to the other could involve a whole-day trek through the mountainous central jungles. Ko Samui's economy now is based on a successful tourist industry, as well as exports of coconut and rubber. Economic growth has brought not only prosperity, but major changes to the island's environment and culture; the first local government on Samui island was established in 1956 with the sanitary district Ko Samui, which however only covered the area around the settlement. In 1963 it was enlarged to cover the entirety of Samui and Pha-Nga islands, which at that time were still in the same district. In 1973, the area of the Ko Pha-Ngan District became a separate sanitary district. Since 1981, the sanitary district covers the area of the whole district.
Like all sanitary districts, Ko Samui became a subdistrict municipality in 1999. In 2008, the subdistrict municipality was upgraded to a town municipality, in 2012, the town was upgraded to a city municipality; the conversion of the municipality into a special administrative area with greater powers of self-governance similar to Pattaya has been discussed since 2008, but as of 2018 no action has been taken. Ko Samui is in the Gulf of Thailand, about 35 km northeast of Surat Thani town, it is the most significant island in the Chumphon Archipelago. The island measures some 25 km at its widest point. To the north are the populated resort islands of Ko Pha-ngan, Ko Tao, Ko Nang Yuan. Close to Bangrak in northeast Samui is the small uninhabited island of Ko Som, to the northeast of Chaweng is the tiny Ko Matlang. To the south are Ko Taen and Ko Matsum, each of which have small tourist facilities. To the far west are 44 other islands which together compose Mu Ko Ang Thong National Park, accessible by a day-trip boat tour from Ko Samui.
The central part of Ko Samui is tropical jungle, including its largest mountain, Khao Pom, peaking at 635 meters. The various lowland and coastal areas are connected by Route 4169, a 51 kilometre-long road, encircling the island. Many other concrete roads branch off from Route 4169 to service other areas. On the west coast of the island is the original capital, which still houses many government offices, as well as two of the island's five major piers. Nathon is the major port for vehicular and goods transportation from the mainland; as the site of the main port and the closest city to the mainland has made Nathon the commercial centre for Samui locals. More the transition from dependence on the local coconut industry along with the continued growth and development of the tourist industry, as well as the northeastern location of the airport, has led to the increase of commercial activity in Chaweng and Bophut. Ko Samui has a tropical savanna climate according to the Köppen climate classification.
The island has a dry season month, with the average monthly precipitation in February falling below 60 mm, the threshold for a tropical dry season month. The temperature is well above the threshold of 18 degrees Celsius year round, indeed closer to an average temperature of 28 degrees; the climate is humid for most of the year. In comparison to Phuket and most of the rest of southern Thailand, Samui's weather is drier; the heaviest precipitation falls in the months of October and November. For the rest of the year, given the tropical climate, rain showers are brief. Ko Samui is an amphoe of Surat Thani Province, divided into seven sub-districts and 39 administrative villages; the entire island is one city municipality. The district covers the island, as well as the Ang Thong archipelago and some other small islands nearby; the district included all of the islands of Surat Thani Province. The islands Ko Pha-ngan and Ko Tao were split off as the minor district Ko Pha-ngan effective 1 October 1970.
In 1980, administrative village number seven of Ang Thong Sub-district covering the islands Ko
Sir Ehud “Udi” Sheleg is a British-Israeli businessman, art dealer and political figure. Sheleg was born in Tel Aviv, his father served with the Royal Air Force in the Second World War. Sheleg is a director of the Halcyon Gallery in London, it is 50% controlled through a British Virgin Islands company by the Tov Settlement, the Sheleg family trust. He has donated over GB£3 million to the Conservative Party, organised fundraisers for Boris Johnson while Johnson was Mayor of London. In July 2019 he was appointed a Knight Bachelor in the 2019 Prime Minister's Resignation Honours and was named by Boris Johnson as the new Treasurer of the Conservative Party. Sheleg's brother Ran was involved in a binary options scandal. Commenting on the appointment of Sheleg as treasurer, Private Eye reported: "Our special report earlier this year revealed not just Sheleg's close relations with Moscow, hosting Russia’s ambassador at the height of post-Crimea-invasion sanctions in 2015, but his major deal with organised-crime-connected figures in establishing a Cyprus outlet of Halcyon the same year.
At a minimum, due diligence appears not to be Sheleg’s strong suit. The Eye’s report showed how Sheleg's Halcyon company had filed erroneous accounts, how in 2009 it had liquidated one of its subsidiary companies, walking away from £4m of debts and carrying on the business under a new company." Private Eye wrote about Sheleg's track record of “unfiled accounts, unpaid suppliers, investigations and VAT penalties from HM Customs and Excise, along with millions of pounds in dodged tax”. His habit of dissolving companies and avoiding liabilities earned him the nickname “Alka Seltzer”. In 2010 Sheleg was involved in a court case involving a missing Rolf Harris painting. Sheleg has been married twice: his first wife was English, he married his second in 2014
The Quantum Communications Hub is a quantum technology research hub established as part of the UK National Quantum Technologies Programme. The hub is a consortium of 8 UK universities and 13 industrial partners, which received funding of £24m over a 5-year period; the hub will develop techniques for quantum key distribution, in particular the chip-scale integration of QKD, as well as developing the UK's first quantum network. The hub is led by the University of York and its academic partners are the University of Bristol, the University of Cambridge, Heriot-Watt University, the University of Leeds, Royal Holloway, University of London, the University of Sheffield and the University of Strathclyde; the Quantum Communications Hub works with 13 industrial partners including Airbus, the European Telecommunication Standards Institute, ID Quantique, the UK National Physical Laboratory, Toshiba
Daniel Celso Jara Martínez is a Paraguayan football midfielder contracted with Lega Pro club San Marino. Jara Martínez started his career with Paraguayan outfit Club Nacional Asunción, with whom he participated in the 2010 Torneo di Viareggio, a youth international tournament during which he was noticed by Palermo director of football Walter Sabatini, he was subsequently offered a trial in February 2010, joining the first team for a number of weeks and taking part to their training sessions. On 31 August 2010 Palermo confirmed the signing of Jara Martínez from Nacional Asunción; the player joined the under-19 youth team, but only made his competitive debut on November due to bureaucratic issues. Since the player has trained with the first-team squad, appeared on the bench for a number of Serie A games. On 25 January 2011, an injury crisis that left Palermo with only an available first-team striker led head coach Delio Rossi to call him up for the 2010–11 Coppa Italia quarter-final game against Parma, a game that saw Jara Martínez making his first team debut as a 70th-minute replacement for Miccoli.
The match ended to a penalty shootout, with Jara Martínez himself scoring the decisive goal that led Palermo into the semi-finals of the competition. This was followed by a lacklustre season where Jara Martínez was benched in the Primavera team too, behind other promising youngsters such as Mauro Bollino, César Verdún and Cephas Malele. On 20 August 2012, Palermo announced to have loaned Jara Martínez to Genoa in an exchange deal that involved the permanent signing of Steve von Bergen for €1.7 million and the permanent sale of Alexandros Tzorvas for €600,000. After spending a full season with the youth squad, he was permanently signed by Genoa and successively loaned to Lega Pro Prima Divisione club Nocerina. On 10 July 2014 he was signed by San Marino
Magic City Memoirs is a 2015 American coming of age drama film directed by Aaron J. Salgado, stars Natalie Martinez, Dominik Garcia-Lorido, Nestor Serrano, Julio Oscar Mechoso, J. R. Villarreal and Michael Cardelle; the film is based on the true stories from Salgado's adolescence. The film takes place in Miami and follows the story of three lifelong friends, from different backgrounds, who are on the verge of high school graduation who indulge in reckless behavior that finds them on the brink of either their graduation or their mortality. Magic City Memoirs follows the lives of three lifelong friends: Mikey Acosta and Stok. Mikey Acosta is a star high school baseball prospect, while Angel is a whiz of a student as well as the son of a prominent Miami politician. Stok is the son of an incarcerated drug lord; these three best friends attempt to navigate through their senior year amongst the pressures and temptations of the city. Natalie Martinez as Mari Dominik Garcia-Lorido as Veronica Suarez Nestor Serrano as Angel Suarez Sr. Julio Oscar Mechoso as Alejandro Acosta J.
R. Villarreal as Mikey Acosta Michael Cardelle as Angel Suarez Jr. Andres Dominguez as Stok Jordi Vilasuso as Eric The film premiered at the Miami International Film Festival, where it won the Pursuit of Perfection Award. Magic City Memoirs on IMDb