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38-625: The Pakistan Army Medical College ( reporting name : AMC ) is a direct reporting detachment and the military medical college located in the Rawalpindi , Punjab in Pakistan. The army's medical college provides medical science education to its cadets before their commissioning into the Pakistan Army's Medical Corps and is not restricted to the military personnel since civilians are also given admissions to seek degrees in medical profession. In 1977,

76-441: A crankshaft or by a swashplate or other suitable mechanism. A flywheel is often used to ensure smooth rotation or to store energy to carry the engine through an un-powered part of the cycle. The more cylinders a reciprocating engine has, generally, the more vibration-free (smoothly) it can operate. The power of a reciprocating engine is proportional to the volume of the combined pistons' displacement. A seal must be made between

114-454: A flywheel , the power from other pistons connected to the same shaft or (in a double acting cylinder ) by the same process acting on the other side of the piston. This is where the piston forms the smallest volume in the cylinder. In most types the expanded or " exhausted " gases are removed from the cylinder by this stroke . The exception is the Stirling engine , which repeatedly heats and cools

152-568: A piston engine , is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion . This article describes the common features of all types. The main types are: the internal combustion engine , used extensively in motor vehicles ; the steam engine , the mainstay of the Industrial Revolution ; and the Stirling engine for niche applications. Internal combustion engines are further classified in two ways: either

190-440: A spark-ignition (SI) engine , where the spark plug initiates the combustion; or a compression-ignition (CI) engine , where the air within the cylinder is compressed, thus heating it , so that the heated air ignites fuel that is injected then or earlier . There may be one or more pistons. Each piston is inside a cylinder , into which a gas is introduced, either already under pressure (e.g. steam engine ), or heated inside

228-651: A bomber aircraft refers to the Tupolev Tu-95 , or "Fulcrum" for the Mikoyan-Gurevich MiG-29 fighter aircraft. For fixed-wing aircraft, one-syllable names are used for propeller aircraft and two-syllable names for aircraft with jet engines. This distinction is not made for helicopters. Before the 1980s, reporting names for submarines were taken from the NATO spelling alphabet . Modifications of existing designs were given descriptive terms, such as " Whiskey Long Bin ". From

266-597: A capacity of 1,820 L (64 cu ft), making a total capacity of 25,480 L (900 cu ft) for the largest versions. For piston engines, an engine's capacity is the engine displacement , in other words the volume swept by all the pistons of an engine in a single movement. It is generally measured in litres (l) or cubic inches (c.i.d., cu in, or in ) for larger engines, and cubic centimetres (abbreviated cc) for smaller engines. All else being equal, engines with greater capacities are more powerful and consumption of fuel increases accordingly (although this

304-469: A cylinder to drive a reciprocating engine in a local-pollution-free urban vehicle. Torpedoes may use a working gas produced by high test peroxide or Otto fuel II , which pressurize without combustion. The 230 kg (510 lb) Mark 46 torpedo , for example, can travel 11 km (6.8 mi) underwater at 74 km/h (46 mph) fuelled by Otto fuel without oxidant . Quantum heat engines are devices that generate power from heat that flows from

342-418: A dozen cylinders or more. Cylinder capacities may range from 10 cm or less in model engines up to thousands of liters in ships' engines. The compression ratio affects the performance in most types of reciprocating engine. It is the ratio between the volume of the cylinder, when the piston is at the bottom of its stroke, and the volume when the piston is at the top of its stroke. The bore/stroke ratio

380-406: A hot to a cold reservoir. The mechanism of operation of the engine can be described by the laws of quantum mechanics . Quantum refrigerators are devices that consume power with the purpose to pump heat from a cold to a hot reservoir. In a reciprocating quantum heat engine, the working medium is a quantum system such as spin systems or a harmonic oscillator. The Carnot cycle and Otto cycle are

418-572: A seal, and more heavily when higher combustion pressure moves around to their inner surfaces. It is common to classify such engines by the number and alignment of cylinders and total volume of displacement of gas by the pistons moving in the cylinders usually measured in cubic centimetres (cm or cc) or litres (l) or (L) (US: liter). For example, for internal combustion engines, single and two-cylinder designs are common in smaller vehicles such as motorcycles , while automobiles typically have between four and eight, and locomotives and ships may have

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456-480: A sequence of strokes that admit and remove gases to and from the cylinder. These operations are repeated cyclically and an engine is said to be 2-stroke , 4-stroke or 6-stroke depending on the number of strokes it takes to complete a cycle. The most common type is 4-stroke, which has following cycles. The reciprocating engine developed in Europe during the 18th century, first as the atmospheric engine then later as

494-699: Is managed by the Five Eyes Air Force Interoperability Council (AFIC), previously known as the Air Standardization Coordinating Committee (ASCC), which is separate from NATO . Based in Washington DC, AFIC comprises representatives from the militaries of three NATO members (Canada, the United Kingdom and United States) and two non-NATO countries (Australia and New Zealand). When the system was introduced in

532-586: Is not to be confused with fuel efficiency , since high efficiency often requires a lean fuel-air ratio, and thus lower power density. A modern high-performance car engine makes in excess of 75 kW/L (1.65 hp/in ). Reciprocating engines that are powered by compressed air, steam or other hot gases are still used in some applications such as to drive many modern torpedoes or as pollution-free motive power. Most steam-driven applications use steam turbines , which are more efficient than piston engines. The French-designed FlowAIR vehicles use compressed air stored in

570-412: Is not true of every reciprocating engine), although power and fuel consumption are affected by many factors outside of engine displacement. Reciprocating engines can be characterized by their specific power , which is typically given in kilowatts per litre of engine displacement (in the U.S. also horsepower per cubic inch). The result offers an approximation of the peak power output of an engine. This

608-394: Is the fictitious pressure which would produce the same amount of net work that was produced during the power stroke cycle. This is shown by: where A p {\displaystyle A_{p}} is the total piston area of the engine, S {\displaystyle S} is the stroke length of the pistons, and V d {\displaystyle V_{d}}

646-459: Is the ratio of the diameter of the piston, or " bore ", to the length of travel within the cylinder, or "stroke". If this is around 1 the engine is said to be "square". If it is greater than 1, i.e. the bore is larger than the stroke, it is "oversquare". If it is less than 1, i.e. the stroke is larger than the bore, it is "undersquare". Cylinders may be aligned in line , in a V configuration , horizontally opposite each other, or radially around

684-425: Is the total displacement volume of the engine. Therefore: Whichever engine with the larger value of MEP produces more net work per cycle and performs more efficiently. In steam engines and internal combustion engines, valves are required to allow the entry and exit of gases at the correct times in the piston's cycle. These are worked by cams, eccentrics or cranks driven by the shaft of the engine. Early designs used

722-423: Is then fed through one or more, increasingly larger bore cylinders successively, to extract power from the steam at increasingly lower pressures. These engines are called compound engines . Aside from looking at the power that the engine can produce, the mean effective pressure (MEP), can also be used in comparing the power output and performance of reciprocating engines of the same size. The mean effective pressure

760-597: Is through the Pakistan Military Academy cadets who are aspired to take Medical Cadet Course. The standardized university entrance exam to the Army Medical College is administrated by the National University of Medical Sciences where the civilians also take for the college admission. Further categories and waivers exist for children of military personnel, as well as foreign nationals. Up till 2021,

798-452: The D slide valve but this has been largely superseded by piston valve or poppet valve designs. In steam engines the point in the piston cycle at which the steam inlet valve closes is called the cutoff and this can often be controlled to adjust the torque supplied by the engine and improve efficiency. In some steam engines, the action of the valves can be replaced by an oscillating cylinder . Internal combustion engines operate through

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836-420: The steam engine . These were followed by the Stirling engine and internal combustion engine in the 19th century. Today the most common form of reciprocating engine is the internal combustion engine running on the combustion of petrol , diesel , liquefied petroleum gas (LPG) or compressed natural gas (CNG) and used to power motor vehicles and engine power plants . One notable reciprocating engine from

874-479: The 1950s, reporting names also implicitly designated potentially hostile aircraft. However, since the end of the Cold War, some NATO air forces have operated various aircraft types with reporting names (e.g. the "Fulcrum" Mikoyan MiG-29 ). The United States Department of Defense (DOD) expands on the NATO reporting names in some cases. NATO refers to surface-to-air missile systems mounted on ships or submarines with

912-596: The 1980s, new designs were given names derived from Russian words, such as " Akula ", or "shark". These names did not correspond to the Soviet names. Coincidentally, "Akula", which was assigned to an attack submarine by NATO, was the actual Soviet name for the ballistic missile submarine NATO named " Typhoon-class ". The NATO names for submarines of the People's Republic of China are taken from Chinese dynasties . Reciprocating engine A reciprocating engine , also often known as

950-505: The NATO names, preferring a native Russian nickname. An exception was that Soviet airmen appreciated the MiG-29 's codename "Fulcrum", as an indication of its pivotal role in Soviet air defence. To reduce the risk of confusion, unusual or made-up names are allocated, the idea being that the names chosen are unlikely to occur in normal conversation and are easier to memorise. For fixed-wing aircraft,

988-460: The Pakistan Army's Corps of Education established the direct military unit to provide the education and training on the medical science as a residential institution for imparting undergraduate medical education to the army's cadets. In Pakistan, the program of Bachelor of Medicine, Bachelor of Surgery (MBBS) is pursued rather than the Doctor of Medicine (MD). From 1977 till 1997, the Army Medical College

1026-483: The World War II era was the 28-cylinder, 3,500  hp (2,600 kW) Pratt & Whitney R-4360 Wasp Major radial engine. It powered the last generation of large piston-engined planes before jet engines and turboprops took over from 1944 onward. It had a total engine capacity of 71.5 L (4,360 cu in), and a high power-to-weight ratio . The largest reciprocating engine in production at present, but not

1064-578: The aircraft's close air support role. Transports have names starting with "C" (for "cargo"), resulting in names like "Condor" for the Antonov An-124 or "Candid" for the Ilyushin Il-76 . The initial letter of the name indicates the use of that equipment. The alphanumeric designations (eg AA-2) are assigned by the Department of Defense . The first letter indicates the type of aircraft, e.g., "Bear" for

1102-470: The crankshaft. Opposed-piston engines put two pistons working at opposite ends of the same cylinder and this has been extended into triangular arrangements such as the Napier Deltic . Some designs have set the cylinders in motion around the shaft, such as the rotary engine . In some steam engines, the cylinders may be of varying size with the smallest bore cylinder working the highest pressure steam. This

1140-430: The cylinder either by ignition of a fuel air mixture ( internal combustion engine ) or by contact with a hot heat exchanger in the cylinder ( Stirling engine ). The hot gases expand, pushing the piston to the bottom of the cylinder. This position is also known as the bottom dead center (BDC), or where the piston forms the largest volume in the cylinder. The piston is returned to the cylinder top (top dead center) (TDC) by

1178-593: The foreign students could apply on the basis of SAT Subject Tests results in lieu of the NUMS test like other medical colleges in Pakistan. The accreditation and the recognition of the medical degrees that are awarded by the Army Medical College is accredited by the Pakistan Medical and Dental Council (PM&DC) and the College of Physicians and Surgeons (CPSP). Reporting name The assignment of reporting names

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1216-588: The largest ever built, is the Wärtsilä-Sulzer RTA96-C turbocharged two-stroke diesel engine of 2006 built by Wärtsilä . It is used to power the largest modern container ships such as the Emma Mærsk . It is five stories high (13.5 m or 44 ft), 27 m (89 ft) long, and weighs over 2,300 metric tons (2,535 short tons ; 2,264 long tons ) in its largest 14 cylinders version producing more than 84.42 MW (113,209 bhp). Each cylinder has

1254-483: The number of syllables indicates the type of the aircraft's engine. Single-syllable code names denote reciprocating engine or turboprop , while two-syllable code names denote jet engine . Bombers have names starting with the letter "B", and names like "Badger" ( Tupolev Tu-16 ), "Blackjack" ( Tupolev Tu-160 ) and "Bear" ( Tupolev Tu-95 ) have been used. "Frogfoot", the reporting name for the Sukhoi Su-25 , references

1292-410: The ones most studied. The quantum versions obey the laws of thermodynamics . In addition, these models can justify the assumptions of endoreversible thermodynamics . A theoretical study has shown that it is possible and practical to build a reciprocating engine that is composed of a single oscillating atom. This is an area for future research and could have applications in nanotechnology . There are

1330-516: The same names as the corresponding land-based systems, but the US DOD assigns a different series of numbers with a different suffix (i.e., SA-N- versus SA-) for these systems. The names are kept the same as a convenience. Where there is no corresponding system, a new name is devised. The Soviet Union did not always assign official "popular names" to its aircraft, but unofficial nicknames were common as in any air force . Generally, Soviet pilots did not use

1368-499: The same sealed quantity of gas. The stroke is simply the distance between the TDC and the BDC, or the greatest distance that the piston can travel in one direction. In some designs the piston may be powered in both directions in the cylinder, in which case it is said to be double-acting . In most types, the linear movement of the piston is converted to a rotating movement via a connecting rod and

1406-407: The sliding piston and the walls of the cylinder so that the high pressure gas above the piston does not leak past it and reduce the efficiency of the engine. This seal is usually provided by one or more piston rings . These are rings made of a hard metal, and are sprung into a circular groove in the piston head. The rings fit closely in the groove and press lightly against the cylinder wall to form

1444-607: Was affiliated with the biology department of the Quaid-i-Azam University (Qau) for its degree accreditation. In 1998, the college was made constituent college of the National University of Sciences and Technology (Pakistan) (NUST) until 2015 when the school was made constituent to the National University of Medical Sciences (NUMS). The admission to the Army Medical College is given through two methods: one

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