Main battle tank

A main battle tank known as a battle tank or universal tank, is a tank that fills the armor-protected direct fire and maneuver role of many modern armies. Cold War-era development of more powerful engines, better suspension systems and lighter weight composite armor allowed a tank to have the firepower of a super-heavy tank, armor protection of a heavy tank, mobility of a light tank all in a package with the weight of a medium tank. Through the 1960s, the MBT replaced all other tanks, leaving only some specialist roles to be filled by lighter designs or other types of armored fighting vehicles. Today, main battle tanks are considered a key component of modern armies. Modern MBTs operate alone, as they are organized into armoured units which involve the support of infantry, who may accompany the MBTs in infantry fighting vehicles, they are often supported by surveillance or ground-attack aircraft. During World War I, combining tracks and guns into a functional vehicle pushed the limits of mechanical technology.

This limited the specific battlefield capabilities. A design might have armour, or firepower, but not all three at the same time. Facing the deadlock of trench warfare, the first tank designs focused on crossing wide trenches, requiring long and large vehicles, such as the British Mark I tank. Tanks that focused on other combat roles were smaller, like the French Renault FT. Many late-war and inter-war tank designs diverged from these according to new, though untried, concepts for future tank roles and tactics; each nation tended to create its own list of tank classes with different intended roles, such as "cavalry tanks", "breakthrough tanks", "fast tanks", "assault tanks". The British maintained cruiser tanks that focused on speed, infantry tanks that traded speed for more armour. After years of isolated and divergent development, the various interwar tank concepts were tested with the start of World War II. In the chaos of blitzkrieg, tanks designed for a single role found themselves forced into battlefield situations they were ill-suited for.

During the war, limited-role tank designs tended to be replaced by more general-purpose designs, enabled by improving tank technology. Tank classes became based on weight; this led to new definitions of heavy and light tank classes, with medium tanks covering the balance of those between. The German Panzer IV tank, designed before the war as a "heavy" tank for assaulting fixed positions, got redesigned during the war with armour and gun upgrades to allow it to take on anti-tank roles as well, was reclassified as a medium tank; the second half of World War II saw an increased reliance on general-purpose medium tanks, which became the bulk of the tank combat forces. These designs massed about 25–30 tonnes, were armed with cannons around 75 mm, powered by engines in the 400 to 500 hp range. Notable examples include the US M4 Sherman. Late war tank development placed increased emphasis on armour and anti-tank capabilities for medium tanks: The German Panther tank, designed to counter the Soviet T-34, had both armament and armour increased over previous medium tanks.

Unlike previous Panzer designs, its frontal armor was sloped for increased effectiveness. It was equipped with the high-velocity long-barreled 75 mm KwK 42 L/70 gun, able to defeat the armor of all but the heaviest Allied tank at long range; the powerful Maybach HL230 P30 engine and robust running gear meant that though the Panther tipped the scales at 50 tons – sizeable for its day – it was quite maneuverable, offering better off-road speed than the Panzer IV. However, its rushed development led to maintenance issues; the Soviet T-44 incorporated many of the lessons learned with the extensive use of the T-34 model, some of those modifications were used in the first MBTs, like a modern torsion suspension, instead of the Christie suspension version of the T-34, a transversally mounted engine that simplified its gearbox. It is seen as direct predecessor of the T-54, as the T-44 was the first Soviet tank with a suspension sturdy enough to be able to mount a 100 mm cannon; the T-54 was the first Soviet MBT, with the first prototype produced in 1945, "was used more extensively that any other Cold War or modern MBT to date... being associated with colonial or independence wars all around the globe and still one of the most common pieces of equipment of any armored force today".

The American M26 Pershing, a medium tank to replace the M4 Sherman, innovated many features common on post-war MBTs. These features include an automatic transmission mounted in the rear, torsion bar suspension and had an early form of a powerpack; the M26, suffered from a weak engine and was somewhat under powered. The design of the M26 had profound influence on American postwar medium and Main Battle tanks: "The M26 formed the basis for the postwar generation of U. S. battle tanks from the M46 through the M47, M48, M60 series." In Britain, tank development had continued down the parallel development of cruiser tanks and infantry tanks. Development of the Rolls-Royce Meteor engine for the Cromwell tank, combined with efficiency savings elsewhere in the design doubled the horsepower for cruiser tanks; this increase led to speculation of a "Universal Tank", able to take on the roles of both a cruiser and an infantry tank by combining heavy armour and manoeuvrability. Field Marshal Bernard Montgomery is acknowledged as the main advocate of the British universal tank conc


Ōbaku-san Manpuku-ji is a temple located in Uji, Kyoto. It is the head temple of the Japanese Ōbaku Zen sect, named after Wanfu Temple in China; the mountain is named after Mount Huangbo, where the Chinese temple is situated. The temple was founded in 1661 by his disciple Muyan. In 1664 control of the temple passed after many Chinese monks followed as head priests. Only the fourteenth priest and his successors are Japanese. On May 21, 1673 Yinyuan dies here; the art of Senchadō is tied to the temple due to its founder. The temple structures were constructed in Ming China's architectural style; the arrangement of buildings follows Ming Dynasty architectural style, representing an image of a dragon. The temple features an exemplary gyoban; the temple treasure house contains a complete collection of Buddhist scriptures completed in 1678 and comprising 60,000 printing blocks, which are still in use. The production of the printing blocks was funded by donations collected throughout the country for many years.

The temple's main statue is a seated Gautama Buddha. Sculptures by the Chinese sculptor known as Han Do-sei and latticed balustrades can be seen. Media related to Manpuku-ji at Wikimedia Commons Japanese Buddhism Zen Egoku Dōmyō Glossary of Japanese Buddhism—explanation of terms concerning Japanese Buddhism, Japanese Buddhist art, Japanese Buddhist temple architecture Titsingh, Isaac.. Annales des empereurs du Japon. Paris: Oriental Translation Fund of Great Britain and Ireland. OCLC 251800045.

Ptisana purpurascens

Ptisana purpurascens is a large fern belonging to the botanical family Marattiaceae. It has a globular rhizome with stipule-like fleshy outgrowths; the leaves are twice pinnate and up to 1 metre long. Every pinnule has up to six pairs of leaflets; the petioles are dark-purplish, hence the name'purpurascens' meaning'becoming purple'. The sporangia are fused in all Ptisana into a bivalvate synangium. Conservation plans have been proposed for Ptisana purpurascens, an endemic of the distant Ascension Island in the South Atlantic, where a single population remains on Green Mountain. While the mature plants are still present in large numbers, long-term threats to its survival exist in the form of competition with alien invasive species like introduced plants such as Buddleja madagascariensis and grazing by sheep and rabbits. Successful reproduction is rare, making the species endangered. Gray, A. Palembe, T. Stroud, S. 2005. The conservation of the endemic vascular flora of Ascension Island and threats from alien species.

Oryx 39: 449-453. See the ARKive site for additional information