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Oerlikon 20 mm cannon

The Oerlikon 20 mm cannon is a series of autocannons, based on an original German Becker Type M2 20 mm cannon design that appeared early in World War I. It was produced by Oerlikon Contraves and others, with various models employed by both Allied and Axis forces during World War II, many versions are still in use today. During World War I, the German industrialist Reinhold Becker developed a 20 mm caliber cannon, known now as the 20 mm Becker using the Advanced Primer Ignition blowback method of operation; this had a cyclic rate of fire of 300 rpm. It was used on a limited scale as an aircraft gun on Luftstreitkräfte warplanes, an anti-aircraft gun towards the end of that war; because the Treaty of Versailles banned further production of such weapons in Germany, the patents and design works were transferred in 1919 to the Swiss firm SEMAG based near Zürich. SEMAG continued development of the weapon, in 1924 had produced the SEMAG L, a heavier weapon that fired more powerful 20×100mmRB ammunition at a higher rate of fire, 350 rpm.

In 1924 SEMAG failed. The Oerlikon firm, named after the Zürich suburb of Oerlikon where it was based acquired all rights to the weapon, plus the manufacturing equipment and the employees of SEMAG. In 1927 the Oerlikon S was added to the existing product line; this fired a still larger cartridge to achieve a muzzle velocity of 830 m/s, at the cost of increased weight and a reduced rate of fire. The purpose of this development was to improve the performance of the gun as an anti-tank and anti-aircraft weapon, which required a higher muzzle velocity. An improved version known as the 1S followed in 1930. Three sizes of gun with their different ammunition and barrel length, but similar mechanisms, continued to be developed in parallel. In 1930 Oerlikon reconsidered the application of its gun in aircraft and introduced the AF and AL, designed to be used in flexible mounts, i.e. manually aimed by a gunner. The 15-round box magazine used by earlier versions of the gun was replaced by drum magazine holding 15 or 30 rounds.

In 1935 it made an important step by introducing a series of guns designed to be mounted in or on the wings of fighter aircraft. Designated with FF for Flügelfest meaning "wing-mounted", these weapons were again available in the three sizes, with designations FF, FFL and FFS; the FF fired a larger cartridge than the AF, 20x72RB, but the major improvement in these weapons was a significant increase in rate of fire. The FF weighed 24 kg and achieved a muzzle velocity of 550 to 600 m/s with a rate of fire of 520 rpm; the FFL of 30 kg fired a projectile at a muzzle velocity of 675 m/s with a rate of fire of 500 rpm. And the FFS, which weighed 39 kg, delivered a high muzzle velocity of 830 m/s at a rate of fire of 470 rpm. Apart from changes to the design of the guns for wing-mounting and remote control, larger drums were introduced as it would not be possible to exchange magazines in flight. For the FF series drum sizes of 45, 60, 75 and 100 rounds were available, but most users chose the 60-round drum.

The 1930s were a period of global re-armament, a number of foreign firms took licenses for the Oerlikon family of aircraft cannon. In France, Hispano-Suiza manufactured development of the FFS as the Hispano-Suiza HS.7 and Hispano-Suiza HS.9, for installation between the cylinder banks of its V-12 engines. In Germany, Ikaria further developed the FF gun as firing 20x80RB ammunition, and the Imperial Japanese Navy, after evaluating all three guns, ordered developments of the FF and FFL as the Type 99-1 and Type 99-2. The incorporation of the improvements of the FFS in a new anti-aircraft gun produced, in 1938, the Oerlikon SS. Oerlikon realized further improvements in rate of fire on the 1SS of 1942, the 2SS of 1945 which achieved 650 rpm. However, it was the original SS gun, adopted as anti-aircraft gun, being widely used by Allied navies during World War II; this gun used a 400-grain charge of IMR 4831 smokeless powder to propel a 2,000-grain projectile at 2,800 feet per second. The Oerlikon FF was installed as armament on some fighters of the 1930s, such as the Polish PZL P.24G.

Locally produced derivatives of the Oerlikon cannon were used much more extensively, on aircraft, on ships and on land. In the air, the Ikaria MG FF was used as armament on a number of German aircraft, of which the most famous is the Messerschmitt Bf 109; the Japanese Navy used their copy of the FF, designated the Type 99 Mark One cannon on a number of types including the Mitsubishi A6M Zero. In the war, they equipped fighters including the Zero with the Type 99 Mark Two, a version of the more powerful and faster-firing Oerlikon FFL; the French firm of Hispano-Suiza was a manufacturer of aircraft engines, it marketed the moteur-canon combination of its 12X and 12Y engines with a H. S.7 or H. S.9 cannon installed between the cylinder banks. The gun fired through the hollow propeller hub, this being elevated above the crankcase by the design of the gearing; such armament was installed on the Morane-Saulnier M. S.406 and some other types. Similar German installations of the MG FF were not successful.

The Oerlikon became best known in its naval applications. The Oerlikon was not looked upon favorably by the Royal Navy as a short-range anti-aircraft gun. All through 1937-1938 Lord Louis Mountbatten a Captain in the Royal Navy, waged a lone campaign within the Royal Navy to set up an unprejudiced trial for the Oerlikon 20 mm gun, but it was all in vain, it was not until the Commander-in-Chief of the Home Fleet, Admiral Sir Roger Backhouse, was appoin

Mahalaxmi Express

The 17411/17412 Mahalaxmi Express is an express train belonging to Indian Railways that runs between Mumbai and Kolhapur in India. It is a daily service, it operates as train number 17411 from Mumbai CSMT to Kolhapur SCSMT and as train number 17412 in the reverse direction. Before gauge conversion, this train ran in two sections: 1- Bengaluru - Miraj Mahalaxmi Metre gauge Express, 2- Kolhapur - Miraj - Mumbai Mahalaxmi express. After gauge conversion Miraj-Bangalore train was discontinued and new direct train between Kurla and Bangalore was introduced, it is named after Mahalakshmi temple in Kolhapur The 17411/7412 Mahalaxmi Express presently has 1 AC 1st Class cum AC 2 tier, 1 AC 2 tier, 2 AC 3 tier, 13 Sleeper Class & 4 General Unreserved coaches. As with most train services in India, Coach Composition may be amended at the discretion of Indian Railways depending on demand. Mumbai CSMT - Kolhapur SCSMT Mahalaxmi express was introduced in 1971. Passengers were transferred from Slip coaches of Bengaluru Miraj express to Mahalaxmi express at Miraj Junction.

After gauge conversion Bengaluru Miraj slip Express was discontinued and Kurla Bengaluru express was introduced. Now 17411 Mahalaxmi Express covers the distance of 518 kilometres in 11 hours 05 mins & 11 hours 05 mins as 17412 Mahalaxmi Express; as its average speed in both directions is below 55 km/hr as per Indian Railway rules, it does not have a Superfast surcharge. Dual traction WCAM 2/2P or WCAM 3 locos haul the train from Mumbai CST until Pune Junction after which a Pune based WDM 3A Or WDP 4 takes over until Kolhapur. On 27 July 2019, 17411 Mahalaxmi Express was stuck between Badlapur Station & Vangani Station for 12-15 hours after heavy rains & flooding from nearby Ulhas River. Approx 1050 passengers were rescued by NDRF, Indian Navy, Indian Air Force, local police and local people of Vangani including 9 pregnant women. Koyna Express Sahyadri Express https://web.archive.org/web/20160314234300/http://enquiry.indianrail.gov.in/ntes/

Erimo Seamount

Erimo Seamount is a seamount off Hokkaido, Japan. Located close to the intersection between the Kuril-Kamchatka and Japan Trenches, it is in the process of being subducted; the Cretaceous seamount is covered by a limestone cap. Tiltmeters have been installed on its top. Erimo Seamount lies southeast of Cape Erimo of Japan; the seamount lies close to the intersection between the Kuril–Kamchatka Trench to the northeast and the Japan Trench to the south. Erimo Seamount lies 15 kilometres oceanward and south and east from the trenches and it forms the northern tip of the Japan Trench. Other seamounts in the area are Takuyo-Daiichi to the east-northeast and Ryofu-Daini to the east-southeast, there is evidence of another seamount northwest of Erimo and in the process of being subducted; as such a seamount or a seamount chain subducted it indented the trenches, forming a 20 kilometres re-entrant. The seamount is a guyot which rises about 4.2 kilometres to a depth of 3,700 metres -3,800 metres, where a flat top is covered by early Cretaceous limestone that contains gastropods, green algae and red algae from that time.

Erimo Seamount is cut by normal faults that run parallel to the Kuril-Kamchatka Trench, the seamount is tilting and beginning to break apart as its subduction starts. It has a volume of about 1,100 cubic kilometres, making it a mid-sized seamount by Pacific Ocean seamount standards, with an northeast-southwest elongated shape and a maximum width of 35 kilometres and recognizable rift zones; the crust underneath Erimo contains the magnetic anomaly M8 and has an age of about 120 million years. Volcanic rocks dredged from Erimo Seamount include alkali basalt, brecciated basalts, silty sandstone, trachyandesites or trachytes. During the Cretaceous, carbonate rocks were emplaced at shallow depth on the seamount, which subsided by about 3 kilometres; as the seamount has entered the trench, further subsidence of about 800 metres has taken place. Erimo Seamount close to a spreading center. Cretaceous volcanic activity has generated seamounts all across the Western Pacific Ocean, but Erimo today is inactive.

This seamount appears to be part of a large hotspot-generated seamount province whose youngest activity is located in French Polynesia