A Stirling engine is a heat engine, operated by a cyclic compression and expansion of air or other gas at different temperatures, such that there is a net conversion of heat energy to mechanical work. More the Stirling engine is a closed-cycle regenerative heat engine with a permanently gaseous working fluid. Closed-cycle, in this context, means a thermodynamic system in which the working fluid is permanently contained within the system, regenerative describes the use of a specific type of internal heat exchanger and thermal store, known as the regenerator. Speaking, the inclusion of the regenerator is what differentiates a Stirling engine from other closed cycle hot air engines. Conceived in 1816 as an industrial prime mover to rival the steam engine, its practical use was confined to low-power domestic applications for over a century. Robert Stirling is considered as one of the fathers of hot air engines, notwithstanding some earlier predecessors, notably Amontons, who succeeded in building, in 1816, the first working hot air engine.

He has been followed by Cayley. This engine type was of those in which the fire is enclosed, fed by air pumped in beneath the grate in sufficient quantity to maintain combustion, while by far the largest portion of the air enters above the fire, to be heated and expanded. Stirling came up with a first air engine in 1816; the principle of the Stirling Air Engine differs from that of Sir George Cayley, in which the air is forced through the furnace and exhausted, whereas in Stirling’s engine the air works in a closed circuit. It was to it. A two horse-power engine, built in 1818 for pumping water at an Ayrshire quarry, continued to work for some time, until a careless attendant allowed the heater to become overheated; this experiment proved to the inventor that, owing to the low working pressure obtainable, the engine could only be adapted to small powers for which there was at that time no demand. The Stirling 1816 patent was about an "Economiser", the predecessor of the regenerator. In this patent he describes the "economiser" technology and several applications where such technology can be used.

Out of them came a new arrangement for a hot air engine. In 1818, one engine was built to pump water from a quarry in Ayrshire, but due to technical issues, the engine was abandoned for a time. Stirling patented a second hot air engine, together with his brother James, in 1827, they inverted the design so that the hot ends of the displacers were underneath the machinery and they added a compressed air pump so the air within could be increased in pressure to around 20 atmospheres. The two Stirling brothers were followed shortly after by Parkinson & Crossley and Arnott in 1829; these precursors, to whom Ericsson should be added, have brought to the world the hot air engine technology and its enormous advantages over the steam engine. Each of them came with his own specific technology, although the Stirling engine and the Parkinson & Crossley engines were quite similar, Robert Stirling distinguished himself by inventing the regenerator. Parkinson and Crosley introduced the principle of using air of greater density than that of the atmosphere, so obtained an engine of greater power in the same compass.

James Stirling followed this same idea. The Stirling patent of 1827 was the base of the Stirling third patent of 1840; the changes from the 1827 patent were minor but essential, this third patent led to the Dundee engine. James Stirling presented his engine to the Institution of Civil Engineers in 1845; the first engine of this kind which, after various modifications, was efficiently constructed and heated, had a cylinder of 30 centimetres in diameter, with a length of stroke of 60 centimetres, made 40 strokes or revolutions in a minute. This engine moved all the machinery at the Dundee Foundry Company's works for eight or ten months, was found capable of raising 320,000 kgs 60 cm in a minute, a power of 16 kilowatts. Finding this power insufficient for their works, the Dundee Foundry Company erected the second engine, with a cylinder of 40 centimetres in diameter, a stroke of 1.2 metres, making 28 strokes in a minute. When this engine had been in continual operation for upwards of two years, it had not only performed the work of the foundry in the most satisfactory manner, but had been tested to the extent of lifting nearly 687 tonnes, a power of 34 kilowatts.

This gives a consumption of 1.2 kilograms per horse-power per hour. This performance was at the level of the best steam engines whose efficiency was about 10%. After James Stirling, such efficiency was possible only thanks to the use of the economiser; the Stirling engine was invented and patented in 1816. It followed earlier attempts at making an air engine but was the first put to practical use when, in 1818, an engine built by Stirling was employed pumping water in a quarry; the main subject of Stirling's original patent was a heat exchanger, which he called an "economiser" for its en

Northport High School is a four-year secondary school in East Northport, New York, that serves as the high school for the Northport-East Northport Union Free School District, composed of Northport, Eatons Neck and much of East Northport, all located in the Town of Huntington. Northport High School is home to over 2,000 students and 270 staff members and offers the International Baccalaureate program, two National Academy programs, Project Lead the Way, Project P. A. T. C. H. and more than 20 Advanced Placement courses. The school's athletic teams are known as the Tigers. Northport High School is located on the corner of Laurel Hill Roads. Although it's called Northport High School, it technically sits on East Northport land. To the west is a Wilson Technological Center campus, part of Western Suffolk BOCES; the Long Island Rail Road's Port Jefferson Branch bounds the school to the south. A high school department was first organized in Northport in 1896, with the first graduating class following in 1900.

Classes were held along with other grade levels at the only School in Northport located on School Street. In 1924, all grades were relocated to a new 500-student K-12 school located on Laurel Avenue. In 1938 all elementary school students were transferred out to newly constructed schools, leaving the Laurel Avenue school as a Junior/Senior High School. Laurel Avenue School functions as the district office. After World War II, servicemen returning from overseas brought tremendous population growth to suburban Long Island; the subsequent baby boom led to explosive school enrollment, which resulted in rampant school overcrowding throughout the 1950s. To accommodate this growth the High School and Junior High School had to separate. In January 1956 the High School relocated to a new campus-style school located on Middleville Road; this was the third home for Northport High School students but the first facility to bear the name Northport High School. But the new school building still couldn't remedy the overcrowding problem, forcing the high school to become a three-year school by moving the 9th grade down to the Junior High Schools.

As overcrowding continued to worsen, Northport High School had to go on an overlapping session in 1962-63, on double session from 1964 to 1966. The overcrowding problem was remedied with the construction of a new Northport High School on Laurel Hill Road; this new school building opened its doors to 1500 students in the fall of 1966, remains the location of Northport High School today. In 1988 the school district moved 9th grade back to the High School after 29 years, renamed all Junior High Schools "Middle Schools". Over 25,000 students have graduated from Northport High School since its inception in 1896; the main part of the school began construction in 1963, opening for the 1966-67 school year on September 7, 1966. A few years the L wing began construction and opened for the 1969-70 school year on September 3, 1969. A unique feature of the school building is the large open area, called the Commons, that visitors enter into from the main entrance; the Commons acts as a hub for the entire school.

Both the large and small cafeteria, faculty dining room and auditorium are located directly off the Commons, from which students may visit The Tiger's Den and access all of the schools wings. There is a balcony on the north side, providing access to the school's administrative offices and counseling center; the Commons is a favorite hangout of NHS students who congregate there before and after school, during lunch and free periods. In each corner lies the "wells," enclosed recessed areas where students can catch up on work, socialize or relax; the largest well has been designated for the senior class through decades of tradition, leaving the two smaller wells for the junior and sophomore classes. As part of an extensive grade restructuring of the entire Northport-East Northport Union Free School District in 1988, the 9th grade was reassigned from each of the junior high schools to the high school; this created two incoming classes that year, including freshmen for the first time. Since there was no existing well for the new freshman class and one could not be constructed, the high school built the freshman benches instead.

A smaller theater used by drama classes is located just beyond the commons to the northeast, as are two gyms to the southwest. The small gym contains a rock climbing an archery court. Beyond the library on the east side of the building is another, albeit smaller open area, known as the Small Commons, possessing only islands of lockers. In 2003, the school expanded; the new K-wing added family and consumer science classrooms on the first floor where the student-run preschool is located and additional regular classrooms on the second floor. The existing A-wing saw a new dance room. Additionally, in the A Wing photography labs, car care classrooms, music administrative office, music classroom, music computer lab, an orchestra room were added; the PE Wing saw renovations. The old weight room was remade into two health infusion classrooms, a section was added onto the Small Gym. A new weight room was built off of the small gym. A part of the existing L wing underwent renovations. Construction was complete for the 2004–05 school year.

NHS offers a wide variety of classes in many subjects. Advance Placement courses are offered in all the five core departments of English, foreign languages, mathematics and social studies. In mathematics, the school offers one and two year acce

Gehazi, Geichazi, or Giezi is a figure found in the Books of Kings in the Hebrew Bible. A servant of the prophet Elisha, Gehazi enjoyed a position of power but was corrupt, misusing his authority to cheat Naaman the Syrian, a general afflicted with leprosy; as punishment, Elisha cursed Gehazi, transferring Naaman's leprosy to him and his descendants forever. In Rabbinic literature, Gehazi is identified as one of four commoners who forfeited his share in the afterlife because of his wickedness, he is the subject of a poem by Rudyard Kipling. Two meanings for the name "Gehazi" have been suggested: "valley of vision" or "valley of avarice". Gehazi was the servant of the prophet Elisha, he appears in connection with the history of the Shunammite woman and her son and of Naaman the Syrian. On the latter occasion, overcome with avarice, obtained in the prophet's name two talents of silver and two changes of garments from Naaman, he was guilty of duplicity and dishonesty of conduct, causing Elisha to denounce his crime with righteous sternness, determine that "the leprosy of Naaman would cleave to him and his descendants for ever".

After Elisha cursed Gehazi, Gehazi became leprous "as white as snow". In the biblical narrative, he appeared before King Joram, to whom he recounted the great deeds of his master; the Cambridge Bible for Schools and Colleges suggests that "it is probable that the accounts of Elisha’s work and influence are not related in their chronological order". In Rabbinic literature, Gehazi is identified as one of four commoners who forfeited his share in the Jewish afterlife, due to his wickedness and consistent refusal to repent in the presence of an upstanding example such as Elisha, he is ostensibly the subject of Rudyard Kipling's poem Gehazi, thought to be aimed at Rufus Isaacs, a member of the British Liberal government at the time the poem was composed. Gehazi appears in John Bunyan's Pilgrim's Progress. Jewish Encyclopedia This article incorporates text from a publication now in the public domain: Easton, Matthew George. "Gehazi". Easton's Bible Dictionary. T. Nelson and Sons