Kuusalu Parish () is a rural municipality in northern Estonia, the largest in Harju County. After joining with the adjacent Loksa Parish in 2005, the municipality has now a population of 6,863 (as of 1 January 2009) and covers an area of . The population density is 9.7 inhabitants per km2.

A significant share of the municipality's territory (between 40% and 60%) is covered by protected areas, as large parts of the Lahemaa National Park and Põhja-Kõrvemaa Nature Reserve are situated there. The eastern part of the municipality is home to the largest military training area in Estonia, the central training area of Estonian Defence Forces.

The administrative centre of the municipality is Kiiu. There is a total of 3 small boroughs — Kuusalu (1225 inhabitants), Kiiu (893 inhabitants) and Kolga (501 inhabitants) — and 64 villages in Kuusalu Parish: Allika, Andineeme, Aru, Haavakannu, Hara, Hirvli, Ilmastalu, Joaveski, Juminda, Kaberla, Kahala, Kalme, Kasispea, Kemba, Kiiu-Aabla, Kodasoo, Koitjärve, Kolga-Aabla, Kolgaküla, Kolgu, Kõnnu, Kosu, Kotka, Külmaallika, Kupu, Kursi, Kuusalu, Leesi, Liiapeksi, Loksa, Mäepea, Murksi, Mustametsa, Muuksi, Nõmmeveski, Pala, Pärispea, Parksi, Pedaspea, Põhja, Pudisoo, Rehatse, Rummu, Salmistu, Saunja, Sigula, Sõitme, Soorinna, Suru, Suurpea, Tammispea, Tammistu, Tapurla, Tõreska, Tsitre, Turbuneeme, Uuri, Vahastu, Valgejõe, Valkla, Vanaküla, Vihasoo, Viinistu, Virve.

The current mayor () is Terje Kraanvelt.

Religion

Gallery

See also
Kuusalu JK Rada

References

External links
Official website (available only in Estonian)

Kuusalu Parish


The Brazilian Army Aviation Command () is a component of the Brazilian Army containing the army's helicopter units.

Tasks
The task of the Brazilian Army Aviation Command is to provide organic airmobility and support the ground forces by providing tactical air support, close air support and reconnaissance.

History
The origin of the Brazilian Army Aviation lies in the Paraguayan War, with on the one side Brazil, Argentina and Uruguay (the Triple Alliance) and on the other Paraguay, when the commander-in-chief of the Brazilian forces, Duke of Caxias, deployed observation balloons in the field to observe the enemy troops.

One of the first army aviators was Ricardo Kirk during the Contestado War 1912–1916, using monoplanes to support ground forces. These missions were predominantly flown for reconnaissance purposes.

In 1941, upon the creation of the Aeronautics Ministry and of the Brazilian Air Force (FAB), Military Aviation, which was the name of the army branch that operated the aircraft, ended its operations as all flying tasks brought under the aegis of the Brazilian Air Force.

In 1986 Brazilian army aviation was re-established to operate helicopters in support of the Brazilian Army. An Army Aviation Material Directorate (DMAvEx), 1st Army Aviation Brigade () and 1st Army Aviation Battalion () were formed. Taubaté was chosen as garrison, suitably located in the country's greatest industrial and population concentration between Rio de Janeiro and São Paulo. Its rebirth is related to the local production of Helibras, located in Itajubá, Minas Gerais, also in the industrial heartland of Brazil. The initial inventory concentrated on helicopter types, which have dual civilian and military application. As such in 1987 an order was placed with the enterprise. The Helibras HB 350 L1 - Esquilo (license production of the Eurocopter AS350L1) became Attack Helicopter - 1 () with 16 units on order and the Eurocopter AS365 Dauphin in its military version SA.365 K Pantera (later rebranded as Eurocopter AS565 Panther) became Maneuver Helicopter - 1 () with an order for 36 units. The first helicopter was handed over to the Army in April 1989, an HA-1 Esquilo nr. EB-1001.

The Taubaté Aviation Base () was officially formed on November 28, 1989, housing the , the Army Aviation Maintenance and Supply Company (later Army Aviation Logistical Battalion, presently Army Aviation Maintenance and Supply Battalion), joined on September 26, 1991 by a dedicated Army Aviation Training Center (). In July 1993 the 1st Army Aviation Brigade was transformed into the Army Aviation Command. Two new units officially stood up at Taubaté on August 17, 1993. On that day the army aviation changed the designation of its operational units from battalions to squadrons and the two new units and the 1st Army Aviation Battalion were combined into a newly formed 1st Group of Army Aviation (). Correspondingly the  became 1st Squadron / 1st Group of Army Aviation (), the second unit became 2nd Squadron / 1st Group of Army Aviation () and the third unit became 3rd Squadron / 1st Group of Army Aviation (). The expansion of the Brazilian army aviation necessitated the acquisition of additional helicopters to fill the inventory and new helicopters were ordered. These were 20 units of the improved military version Eurocopter Fennec AS 550 A2, which retained HA-1 designation and the name  (Squirrel) in Brazilian Army service. The fleets of HB 350 L1, HB 550 A2 and AS.365K were reshuffled between the three squadrons correspondingly.

In February 1991 the Revolutionary Armed Forces of Colombia made an incursion into Brazilian territory and an air unit of 2 HA-1s and 2 HM-1s was deployed from Taubaté to provide air support to the border guard and jungle infantry units on the ground. In 1993 the deployment became permanent as the army aviation's Amazonia Detachment () in Manaus, the State of Amazonas's capital. With the fleshing up the detachment became 1st Company of the army's 2nd Helicopter Battalion, but in line with the ongoing restructuring it became 1st Squadron of the 2nd Army Aviation Group () on December 15, 1993 to underline the geographical separation from Taubaté and its . An aircraft type dedicated completely to military specifications entered service in 1997 in the form of 4 Sikorsky S-70A Blackhawk. The aircraft were acquired to fulfill Brazil's role as an observer in the UN's MOMEP mission, monitoring the ceasefire after the Cenepa War between Peru and Ecuador. In 1999 these machines and personnel joined the Manaus unit, which after the disbandment of the 1st and 2nd Army Aviation Groups changed designation from 1st Squadron of the 2nd Army Aviation Group () to 4th Army Aviation Squadron () on September 1, 1997 along with the redesignation of the other three operational units. Unlike the 1st, 2nd and 3rd Squadrons, which were operationally under the Army Aviation Command, the 4th Army Aviation Squadron reported to the Amazon Military Command.

On January 1, 2005 the redesignation of the operational army aviation units from battalions to squadrons was reverted and they once again became 1st, 2nd, 3rd and 4th Army Aviation Battalions. On April 25, 2008 the 3rd Army Aviation Battalion was reassigned from Army Aviation Command to the Western Military Command. It remained initially at Taubaté Aviation Base, but steps for its relocation were initiated. Like the 4th Army Aviation Battalion it was decided to move the unit to an Air Force installation - the Campo Grande Air Base, which is also a civilian international airport. The actual transfer of the battalion started in February 2009 with the relocation of 6 HA-1 Fennec helicopters and the activation of the army aviation's Campo Grande Detachment (). The battalion's relocation to Campo Grande with a manpower of up to 400 personnel and 16 helicopters was completed in 2012, also finalising the Brazilian Army Aviation's current order of battle, as of August 2018.

Organisation
The Brazilian Army Aviation battalions are standardised around four types of sub-units - Command and Support Flight (), Reconnaissance and Attack Helicopters Flight (), General Mission Helicopters Flight () and (). A helicopter flight could number between four and ten aircraft. Normally a battalion includes one of each flight types, but with the introduction into service of new aircraft types such as the Eurocopter Cougar and the Jaguar and the formation of new battalions using a flight of existing battalion as the nucleus it is common to see a battalion with two general mission helicopters flights.

 Army Aviation Command based at Taubaté SP which functions as operational command
Army Aviation Directorate based Brasilia which is responsible for the logistics

Brazilian Army Aviation is organised as follows:

LAND OPERATIONS COMMAND () (Brasília)

 Southeastern Military Command (São Paulo)
Army Aviation Command () (Taubaté (SP))
Command ()
Army Aviation Signals Company ()
1st Army Aviation Battalion ()
2nd Army Aviation Battalion ()
Army Aviation Training Center () - Taubaté-SP
Army Aviation Maintenance and Supply Battalion ()
Taubaté Aviation Base () - Taubaté-SP
Western Military Command (Campo Grande)
3rd Army Aviation Battalion () (Campo Grande (MS))
Amazon Military Command (Manaus)
4th Army Aviation Battalion () (Manaus (AM))

The Army Aviation Command provides maintenance, training and doctrine support to the 3rd and 4th Army Aviation Battalions, which are outside of its command structure.

Army Aviation Command also operates and maintains the infrastructures of the Taubaté Military Airfield, thus guaranteeing the aeronautic activity of the units. The 3rd and 4th Battalions use Air Force installations - the Campo Grande and the Manaus air bases respectively.

The army aviation's original fleet of HA-1 Esquilo and HM-1 Pantera helicopters have undergone a MLU. As of 2018 the focus of the Brazilian Army Aviation is the introduction into service of additional Jaguar helicopters at Taubaté and Black Hawk helicopters at Manaus as well as forming its first fixed wing element since 1941 at the 4th Battalion at Manaus with the introduction of between 4 and 8 second-hand Short C-23B Sherpa intended to boost the logistical capabilities of the Brazilian Army in the Amazon region by connecting its capital and main transport hub with remote airstrips, suitable for STOL aircraft only. At a later point in time the Brazilian Army plans to acquire dedicated helicopters after three decades of operating light helicopters in the role with their inherent limitations. It has expressed interest in the Eurocopter Tiger, Agusta A129 Mangusta, Mil Mi-28 and the Bell AH-1Z Viper.

Aircraft

Current inventory

See also
Brazilian Naval Aviation
Brazilian Navy
Brazilian Army
Brazilian Army Aviation
Brazilian Air Force
 Army aviation

References

External links
4th Army Aviation Battalion page in Portuguese
Army Aviation Command page in Portuguese

Army aviation units and formations
Army units and formations of Brazil

Brazilian Army Aviation Command


The Lingnan School () of painting, also called the Cantonese School, is a style of painting from the Guangdong or Lingnan region of China.

This school reflects a style of painting founded in the 19th century in Guangdong province by Two Gaos and one Chen - Gao Jianfu, Gao Qifeng and Chen Shuren, also known as "The three greats of Lingnan" ().

The Lingnan style of painting was revolutionary and innovative compared to traditional Chinese painting, influenced by Nihonga visual arts and by the early Qing painter, Yun Shouping (1633–1690).

In the late 19th century, scholars in China broke through entrenched conservative thoughts and began to actively seek to create and promote new schools and styles of art. This not only cultivated a large amount of ideological progress among social elites but also gave birth to the "eclectic fusion of the Han Chinese and Western style, ancient and modern" Lingnan school. The Lingnan school advocates the introduction of Western painting styles with the integration of Han Chinese and Western paintings, in the spirit of revolution of Oriental arts, while maintaining traditional Han Chinese painting techniques.

This school of painting enjoys considerable fame among Han Chinese peoples. Along with Cantonese opera and Cantonese music, they are known as the "three fineries of Lingnan" (Jyutping: Ling5 Naam4 Saam1 Sau3; Traditional Chinese: 嶺南三秀). Meanwhile, the Lingnan school is listed along with Beijing and Tianjin painting school and Shanghai school as the three pillars of modern Chinese painting.

Name
The term "Lingnan School" was not coined by Lingnan painters. During their era, Gao Jianfu, Gao Qifeng and Chen Shuren, with their bold and innovative style, were given the title of "The Three Greats of Lingnan." This contributed to the formation of the name "Lingnan school". However, Chan expressed his dissatisfaction with the title "Lingnan school" as he felt that it suggested that the school was merely regional and that it did not reflect the absorption of overseas styles and the idealism of innovation in Han Chinese paintings. Gao Jianfu never used the name "Lingnan school of painting," and would rather call it "eclectic."

"Lingnan painting" refers to the work of painters in the Guangdong province in general.

Techniques
According to Wang Lipu's view, Lingnan school is characterized by:
Blank space focus: Lingnan paintings, in line with traditional Han Chinese painting styles, are focused on the "presence of both the real and the surreal", and "paying attention to the places without ink" - inheriting the traditional techniques of ink wash paintings.
Strokes focus: Lingnan school's strokes are complex and anti-tradition, with the goal of achieving magnificence and vividness.
Bright coloring: Influenced by impressionism, Lingnan paintings focus on the light performance. Most of the colors are very bright, in stark contrast to the traditional ink wash painting, which in turn is pale, stressing "With paleness comes the soul of pens and ink".
Rendering of background colors: Since the Tang dynasty poet-artist Wang Wei put forward the idea that ink wash was superior, In general, Han Chinese painting styles focus on the use of ink wash and abstain from coloring. Lingnan school does the opposite.

Notable artists
Chao Shao-an (Zhao Shao'ang)
Guan Shanyue
He Xiangning
Huang Junbi
Li Jinkun
Li Xiongcai
Liu Chuncao
Yang Shan Shen
Au Ho-nien
Ho Fung-lin
Hsin Peng Chiu
Anita Yan Wong

Gallery

See also
Cantonese culture
Culture of Hong Kong

References

External links
岭南画派:岭南派画家陈蕴化建立的介绍岭南画派的网站 (in Mandarin Chinese)
The Lingnan School of Painting - Introduction
In Search of Inspiration

Lingnan school of painting
Art movements in Chinese painting

Lingnan School


The Don Bosco Foundation of Cambodia (DBFC, in Khmer "សាលាដុនបូស្កូនៅប្រទេសកម្ពុជា") is a Non-profit organization of education founded in Cambodia in 1991 to give technical skill education to youth living in extreme poverty and to facilitate the schooling of marginalized children. The organization was a way to answer the needs of a country in its post-war period of reconstruction. DBFC is a branch of the Salesians of Don Bosco. The United Nations asked to the Salesians in Thailand to attend the children and youth of the Cambodian Refugee camps during the 1980s. DBFC answered this request by opening provisional technical schools in the camps. After the peace agreements, the organization was invited by the Cambodian government to settle in the country. The first printing press in Cambodia after the war, was provided by DBFC in the Don Bosco Technical School of Phnom Penh for the republishing, translating and writing of books and documents of education (during the Khmer Rouge Regime books were destroyed). Many schools were rebuilt in the villages and the Organization gained prestige as the first institution to provide technical education and to offer sponsorship to Cambodian children.

History

The genesis of DBFC started in the Khmer Refugee Camps along the Thai-Cambodian border in the early 80's after the 1979's Vietnamese invasion of the Khmer Rouge Cambodian Regime. The full control of the Khmer refugee camps was taken by the Thai Army that did not allow other foreign organizations to come into the camps for any kind of humanitarian activities. In this issue UN insisted to the Thai government to allow foreign organizations to attend the needs of the Khmer refugees. In 1989 Thailand agreed that the UN could send humanitarian help to refugees and among this was education to children and youth. UN asked the Catholic Church through the Catholic Office for Emergency Relief and Refugees. At its time, the Catholic Church asked the Salesians of Don Bosco in Bangkok to do something in technical education for Cambodian girls and boys of the refugee camps.

The Thai Salesians visited the camps allowed by the Thai Army and opened technical centers among the tension of battles in the area. When the war was over and Cambodia had a more independent government, many Cambodian families from the refugee camps returned to their country and the Don Bosco technical centers were necessary anymore. The experience in the camps attracted the attention of the Royal Government of Cambodia that sent a delegation to Thailand to study the works and ways of education of the Salesians of Don Bosco in that country. In this way, the Salesians were invited in 1991 to settle in Cambodia and open educational works for a country completely destroyed by war.

The government put under the custody of the Salesians an orphanage and provided land in what is today the Phnom Penh Thmey District, near the Phnom Penh International Airport (then now as Pochenton Airport,) to build the first technical school that was completed in 1993. The lack of books and didactic material, all destroyed during the long war period, made that the Salesians gave importance to the printing workshops which supplied the first printing press of the country in the post-war period.  The success of the first years of technical education provided by Don Bosco led the Cambodian government to give other lands for educational purposes to the Salesians in Battambang and Sihanoukville. At the same time, the Salesian Sisters joined the project in Cambodia by opening vocational training centers in Phnom Penh. As many young boys and girls came to the technical centers with a poor academic background (by 1999 only 30% of children had basic education due to the lack of schools in most part of the country), DBFC created the Children Fund with the intention to build schools in villages and support an intensive program of sponsorship for children. A technical school was opened in 1997 in Sihanoukville, a literacy center and children home was opened in Poipet in 2004. Other literacy centers were opened in Battambang for labor children of the brick factories in the intention of freeing them from factory life and providing an opportunity for a normal school situation. On February 12, 2007 His Majesty, Norodom Sihamoni, visited the Don Bosco Technical School in Sihanoukville, inaugurated the Don Bosco Hotel School in that city and thanked DBFC for its presence in the reconstruction of Cambodia. In 2011 DBFC opened a new technical school and children fund's branch in Kep province. Through the children fund, Don Bosco educative and protection projects reach all Cambodian provinces supporting children and youth from rural and indigenous communities, as well as children who are physically challenged.

Development

As an NGO, the DBFC is a project with assignment agreement to the Cambodia Ministries.  Its primary purpose is to provide basic education and appropriate technical training to orphaned and marginalized youth that are poor and have no sources of support. These children will be prepared for the job market and for future integration in the society. The new situation of today's Cambodia challenges the Salesian priests, brothers and lay educators to find new initiatives. As a result of poverty, many children were denied access to basic education and therefore, to professional and technical education. Therefore, since 1991 the Don Bosco Foundation of Cambodia has evolved into a new style of salesian presence.

Under a grant from July 1995 to December 2001, USAID/Cambodia has provided support to establish and help with the operation costs of four Salesian Vocational Training Schools in Cambodia. During these six and a half years, the Salesians have trained more than 1500 youth. These young people have mastered new knowledge and skills as well as developed attitudes suitable for the dynamic and changing workplace. Presently 1378 students undergo education in basic employable skills required by industries attracted by the new social and economic programs and strategies of Cambodia. The Technical Schools and Training Centers  in Phnom Penh, Sihanoukville, Battambang and Poipet are still in the process of expanding and developing. The improving of human resources through guided and structured learning activities, provide students with practical know-how and skills by the use of developing training plans, curricula/modules, and/or methods used in the actual training activities.

The local job market demand for Don Bosco Technical School graduates is very encouraging with almost 100% of the yearly trainees finding employment even before their graduation. However, DBFC must strive to secure good jobs and improve employment position through supervised learning method while in school environment with three competitive plus skills factors: Computer, Internet Access and Agriculture/Farming in order to practice appropriate work concepts and skills in improving their training tasks. Don Bosco has also contributed to the technical education in Cambodia by providing translations of technical books into Khmer Language and publishing them.

As a direct result of poverty many children were denied access to primary and secondary education, the Don Bosco Foundation of Cambodia offers scholarships to enable these children to go to school and receive education under the Don Bosco Children Fund.

To meet the needs of children living and working in Bricks Factories in Battambang, Don Bosco Literacy Center has two literacy centers to educate 210 children through an intensive three-year curriculum after which they are reintegrated into government formal high school curriculum.

In response to the HIV/AIDS epidemic in Cambodia, around 450 AIDS orphans and/or children living in AIDS affected families are offered support in order to access to education and health care.

In addition to helping members from the poorest elements of a society, the Salesians have always had a special concern for homeless youth, orphans and young people in difficulties. The Don Bosco Literacy and Skills Training Center Project to support street children and disadvantaged youth in Poipet (border town with Thailand) is a strategy to fight social evil, promote basic education, and improve the life chances of the children and disadvantaged youth.

It is a traditional element in Don Bosco Presences to have a place for more informal education through the Salesian Youth Movement style of seminars, scouting, retreats and youth centers. Don Bosco Youth Center- Kep provides these services.

References

External links
 Official site
 Don Bosco Technical School Sihanoukville
 Don Bosco Hotel School Cambodia
 Don Bosco Technical School Kep Province

Educational organisations based in Cambodia
Catholic organizations
Salesian Order

Don Bosco Cambodia


Les Liaisons dangereuses (English title: Dangerous Liaisons) is a 2003 French television mini-series directed by Josée Dayan starring Catherine Deneuve, Rupert Everett, Nastassja Kinski and Leelee Sobieski.  It is based on the classic 1782 novel Les Liaisons dangereuses by Pierre Choderlos de Laclos.

Plot
An updated adaptation of Choderlos de Laclos' classic 18th Century tale of seduction, betrayal and revenge set in the modern 1960s world of Parisian high society. The beautiful Madame de Merteuil (Catherine Deneuve) seeks vengeance against her ex-lover Gercourt (Andrzej Zulawski) when he becomes engaged to her young goddaughter, Cécile (Leelee Sobieski). Merteuil turns to her ex-lover/partner-in-crime, Valmont (Rupert Everett), famous for his reputation as a Don Juan, to seduce Cécile and emotionally destroy her. While on his mission, Valmont gets sidetracked when he goes to visit his aunt and falls for Madame Tourvel (Nastassja Kinski), a virtuous, married woman who knows of his womanizing ways, but that only makes the challenge more exciting to Valmont. Together, Madame de Merteuil and Valmont make a dangerous team and they will stop at nothing when it comes to matters of the heart.

Cast
 Catherine Deneuve as Marquise Isabelle de Merteuil
 Rupert Everett as Vicomte Sébastien de Valmont
 Nastassja Kinski as Madame Marie de Tourvel
 Danielle Darrieux as Madame de Rosemonde
 Leelee Sobieski as Cécile de Volanges
 Andrzej Zulawski as Antoine Gercourt
 Cyrille Thouvenin as Hugo / Ludovic
 Françoise Brion as Madame Volanges
 Tedi Papavrami as Raphaël Danceny
 Dominique Besnehard as The deputy of the foundation
 Didier Flamand as The Director
 Maria Belooussova as La pianiste de la foundation
 Paolo Capisano as Me Plissu

External links

 Les Liaisons dangereuses at Allmovie
 Les Liaisons dangereuses at the British Film Institute

2000s French television miniseries
Television shows based on French novels
2003 television films
2003 films
Films based on works by Pierre Choderlos de Laclos
Television shows set in France
Works based on Les Liaisons dangereuses
2003 French television series debuts
2003 French television series endings
Films directed by Josée Dayan

Les Liaisons dangereuses (miniseries)


Ezekiel Polk (December 7, 1747 – August 31, 1824) was American  soldier, pioneer and the paternal grandfather of President James Knox Polk.

Early life
Ezekiel Polk was the next youngest of five boys and three girls born to William Polk and Margaret Taylor Polk of Cumberland County, Pennsylvania, near present-day Carlisle. About 1753 the family moved southwestward to the southern boundary of North Carolina in what would become Mecklenburg County. His parents appear to have died shortly afterward, and Ezekiel probably was brought up by his older brother Thomas, the senior member of the family, a leader of the local militia and a member of the first and subsequent North Carolina provincial assemblies.

At age 20 Ezekiel, recently married, was named clerk of court in the new county of Tryon across the Catawba River, where he and his bride established themselves on a  farm just south of Kings Mountain. In 1772, however, the provincial boundary was surveyed, and Polk's property was discovered to lie in South Carolina.

Career
Military service record:
 New Acquisition District Regiment of the South Carolina militia (1775, 1780–1782): First a Lt. Colonel under Col. Thomas Neel in early 1775.
 Then he chose to have an independent company of Rangers prior to 3rd South Carolina Regiment of Rangers being formed on June 6, 1775
 Resigned from South Carolina 3rd Regiment on July 29, 1775.  Authorized to reform his independent Ranger Company again in the New Acquisition District, but he was to remain under command of Col. William Thomson.  His unit was disbanded at the fall of Charleston.
 Later, he was a Lt. Colonel again in the New Acquisition District Regiment.

Polk adapted with increasing difficulty to the shifting boundary and consequent loss of his position as clerk of court. At first he was chosen lieutenant colonel of the district militia. In 1775 he was elected a delegate to the South Carolina Provincial Congress held in June and was commissioned a captain in the Third South Carolina Regiment of Horse Rangers, assigned to the interior, where Whigs and Loyalists were competing for control of the province. But when the regiment was ordered to the coast, Polk balked, marching his men home rather than sacrifice their health, as he put it, for the protection of Lowcountry aristocrats and rice plantation nabobs. He subsequently relented, apologized for his insubordination and was restored to command. He led his company against Loyalist forces in the battle at Reedy River in December 1775 and the following summer commanded 300 militia in a successful expedition against pro-Loyalist Cherokees.

On July 24, 1776, Polk's regiment was adopted into the Continental Army and assigned to the Southern Department. "Captain Ezekiel Polk's Independent Company," according to the U.S. Army's regimental history, was "concurrently redesignated as the 10th Company, 3rd South Carolina Regiment."

Polk may never have been entirely comfortable in South Carolina, and waning popularity and political enmities appear have left him increasingly disgruntled. After being passed over initially as delegate to a provincial congress held in November 1775, he had with great difficulty forced a second election and kept his seat. Probably this aborted rejection continued to rankle. In late 1776 Polk surrendered his commission in the 3rd Regiment and returned to North Carolina, settling down on a  farm about  below Charlotte, the Mecklenburg County seat. Two years later he opened a tavern in town and the following year was named justice of the peace. This period of tranquility was not to last. With the fall of Charleston in 1780 and the subsequent defeat of Horatio Gates at Camden, Lord Charles Cornwallis's triumphant Redcoats marched into North Carolina, the main body encamping a few miles from Polk's farm. The following day, September 26, Cornwallis commandeered the Charlotte home of Ezekiel's brother Thomas and established his headquarters there. Fearing the loss of crops, slaves and his tavern, Ezekiel rode to town and "took protection" from Cornwallis in exchange for peaceful cooperation with the British.

Such an action was not without precedent, and Polk's neighbors evidently did not judge him too harshly, for toward the end of the war the Mecklenburg magistrates, with only two dissenters,  elected him sheriff. At the conclusion of the war, he received a generous acreage of western land for his services during the Revolution and in 1790 was appointed deputy surveyor in the Western District, as Tennessee was then called, and moved with his family to a tract north of the Cumberland River. Indian raids and the prolonged illness and death of his wife in 1791 led to his return to Mecklenburg County. He did not make Tennessee his permanent home until the fall of 1803, when he established himself on a  tract on the Duck River in what is now Maury County.

Polk was a militant Jeffersonian and a Deist (some said an atheist), which put him at loggerheads with much of the family, especially his nephew William Polk's three sons, who were Ezekiel's close Tennessee neighbors, ardent Federalists and orthodox churchmen. The inscription composed for his first wife's tombstone spoke of "a glorious Resurrection to eternal life," but her painful illness and the death of all the children of his second marriage seem to have dampened if not extinguished the bereaved husband's faith.

Marriages
He was married three times. His first wife, Mary Wilson Polk, bore him eight children, including Samuel Polk, the father of James K. Polk, 11th President of the United States. No children of his second wife, Bessie Davis Polk, survived infancy. Some sources identify his second wife as a Polly Campbell. By his third wife, Sofia Neely Lennard Polk, he had four children. He died near Bolivar, Tennessee, August 31, 1824, and was buried in the Polk Cemetery at Bolivar.

Death
Polk composed his own epitaph and left instructions that it be painted on durable wood "as there is no rock in this country fit for grave stones." In its original version, it reads:

Here lies the dust of old E.P.
One instance of mortality
Pennsylvania born, Car'lina bred,
In Tennessee died on his bed
His youthful days he spent in pleasure,
His latter days in gath'ring treasure;
From superstition liv'd quite free
And practiced strict morality.
To holy cheats was never willing
To give one solitary shilling,
He can foresee, and in foreseeing
He equals most of men in being
That church and state will join their pow'r
And mis'ry on this country show'r.
And Methodists with their camp bawling,
Will be the cause of this down falling.
   An era not destined to see,
It waits for poor posterity
First fruits and tithes are odious things
And so are Bishops, Priests and Kings

Ancestry
The ancestry of Ezekiel Polk is largely unknown. It is claimed that his father William Polk is descended from Robert Bruce Polk (1625-1703), a member of Clan Pollock migrated to Maryland; and his mother is a daughter of James Taylor, grandfather of Richard Taylor and great-grandfather  of presidents Zachary Taylor and James Madison. Both ancestries are disproved by newer research.

References

External links

1747 births
1824 deaths
American deists
American pioneers
American slave owners
American surveyors
North Carolina militiamen in the American Revolution
People from Mecklenburg County, North Carolina
People of colonial North Carolina
Ezekiel
South Carolina militiamen in the American Revolution
South Carolina colonial people

Ezekiel Polk


ABC Motors Limited ("All British (Engine) Company") of Hersham, Surrey, England was a manufacturer of cars, aircraft, motor scooters, and engines for road and air. Established by Ronald Charteris in Hersham, Surrey in 1912, its chief designer was the young and talented Granville Bradshaw. It was absorbed into Vickers in 1951 and the factory finally closed in the 1970s. Last occupied by Ian Allan Publishing as Hersham's Riverdene Industrial Estate, the factory was demolished around 2017-2018 and redeveloped as a Lidl supermarket (opened February 2019) with flats above.

Products

The ABC radial aero engines of the World War I period were extremely advanced for their time, and were initially thought to be very promising indeed. Unfortunately they were all more or less plagued by problems – and although a number of types for the Royal Air Force were designed around ABC engines (especially the ill-fated Dragonfly) none saw squadron service with the RAF.

ABC also made a large number of engines for electrical generators and other purposes – mostly with a flat twin cylinder layout and unusual exhaust-over-inlet valve configuration. These smaller ABC engine have the distinction of being possibly the first airborne APUs- the Coastal class blimp (first flown in 1916) had a 1.5-horsepower unit installed to provide electricity for the onboard wireless set, whilst a similar engine was used to power the searchlight of the Supermarine Nighthawk 'Zeppelin killer' of 1917.

Aero engines

 ABC 6 hp Midge (1951)  National Archives Kew (AIR 10/7172)
 ABC 8 hp (1923)
 ABC 30 hp (1912)
 ABC 60 hp (1912)
 ABC 100 hp (1912)
 ABC Dragonfly (1918)
 ABC Gadfly (1920)
 ABC Gnat (1916)
 ABC Mosquito (1916)
 ABC Hornet (1929)
 ABC Scorpion (1923)
 ABC Wasp (1918)

Aircraft
 ABC Robin

Automotive
 ABC (1920 automobile)
 ABC Supersports
 ABC Skootamota
 ABC motorcycles

See also

References

Notes

Bibliography

Lumsden, Alec (1994) 'British Piston Aero Engines and Their Aircraft' (Airlife, Shrewsbury)

Defunct aircraft manufacturers of the United Kingdom
Defunct aircraft engine manufacturers of the United Kingdom
Defunct motor vehicle manufacturers of England
Defunct companies based in Surrey
Vehicle manufacturing companies established in 1912
1912 establishments in England
Vehicle manufacturing companies disestablished in 1951
1951 disestablishments in England
1951 mergers and acquisitions
British companies disestablished in 1951
British companies established in 1912

ABC Motors


Rudolf (Rudi) Lehmann () was a German-born Israeli sculptor and Wood carving artist. He was one of the pioneers of sculpture in the State of Israel.

Biography
Rudolf (Rudi) Lehmann (1903-1977), born in Berlin, August 25, 1903 to non-Jewish German Elizabeth Sender. In 1919 Rudolf was adopted by the Lehmann family.
He was one of the pioneers of wood sculpting in the State of Israel.

Studies
In 1912 in Berlin he practiced, wood sculpture with Ludwig Vordermayer.
In 1917-1922, he studied mechanics and worked as a blacksmith's  apprentice. After studying woodcarving and sculpture with sculptor Harold Isenstein, he attended the :de:Kunsthochschule Berlin-Weißensee (Municipal Art School Berlin-Weißensee), majoring in sculpture and ceramics. During his studies there, he met Hedwig Grossman, whom he later married. In 1928-1930, Lehmann worked for Holzmann's Stone Mason and Carving company. He became a freelance stonemason and sculptor for museums around Germany, including the Pergamon Museum in Berlin, and worked in terra cotta at Hedwig's ceramics workshop. In the summer of 1933, Lehmann immigrated to Mandate Palestine with his wife and settled in Haifa. They established a ceramics testing laboratory at the Technion in  Haifa and settled on Kibbutz Yagur in 1935, where they established a flower pot factory.

In 1937, the couple opened a sculpture studio in Jerusalem, where Lehmann produced miniature carvings from olive wood, ivory, horn and gemstones sold as tourist souvenirs. In 1945-1947, Lehmann worked for the Haganah, building models and ballistic implements. In 1947-1948, he joined the Jewish Agency's Self-Defense Planning Committee.

In 1953, he helped to found the Ein Hod Artists' Village, where he taught sculpture. Among his students were Yigael Tumarkin and Menashe Kadishman. In 1959, Lehmann and his wife moved to Givatayim where he established an art school under the auspices of the Givatayim municipality. The school held classes in sculpture, woodcuts and ceramics for young people and adults.

Lehmann's work was influenced by the Canaanism school of Israeli art. which attempted to create a direct relationship with the Land of Israel by emphasizing simple shapes and motifs from the sculpture and ritual art of early Middle Eastern civilizations.

He died in 1977.

Awards and recognition
1933 Dizengoff Prize for Painting and Sculpture, Municipality of Tel Aviv-Yafo
1951 Dizengoff Prize for Painting and Sculpture, Tel Aviv Museum of Art, Municipality of Tel Aviv-Yafo
1953 Dizengoff Prize for Painting and Sculpture, Municipality of Tel Aviv-Yafo
1966 Dizengoff Prize for Painting and Sculpture, Municipality of Tel Aviv-Yafo

Education
1912 Academy of Berlin, Germany, wood sculpture with Vordermeyer
1917 Berlin, Germany, blacksmithing and metalworking
1922-24 woodcarving and sculpture with sculptor Harold Isenstein
1923 Municipal High School for Art, Berlin, Germany, sculpture and ceramics
1924-28 Modern Art School, Berlin, Germany, sculpture and ceramics

Teaching
1923-25 Art School, Berlin Municipality, Germany
1934 Bezalel Academy of Arts and Design, Jerusalem
1959 Studio in Givatayim, sculpture and ceramics

See also
Visual arts in Israel

References

External links

Jewish emigrants from Nazi Germany to Mandatory Palestine
German art educators
Israeli sculptors
1903 births
1977 deaths

Rudi Lehmann


De Zwaan is an authentic Dutch windmill in the city of Holland, Michigan. The windmill's name is Dutch for The Swan or Graceful Bird. It is the oldest authentic, working Dutch windmill in the United States. De Zwaan is located in Windmill Island municipal park.

History
When Holland, Michigan residents Willard Wichers and Carter Brown were looking for a way to pay homage to the city's Dutch heritage, they began a project to bring a Dutch windmill to the United States. However, many of these monumental structures had suffered serious damage in World War II. As a result, the Dutch government had placed a ban on the sale of windmills outside the Netherlands. Wichers and his group were able to gain an exemption by selecting a heavily damaged mill known as De Zwaan that had been in operation in Vinkel Netherlands since being moved there in 1884 by a family named Van Schayk.  De Zwaan was at the center of a controversy, with three local agencies unable to determine the future of the damaged windmill. The Dutch government decided to sell it to Wichers for $2800, making De Zwaan the last windmill to leave the Netherlands. Windmill authorities in the Netherlands provided the City of Holland with the history of De Zwaan, noting that it had been built in Krommenie, Netherlands, in 1761 as a grain mill set on a raised base to better capture the wind.

In October, 1964, De Zwaan arrived aboard the Prins Willem van Oranje. It was unloaded at the Muskegon harbor and transported by truck to Windmill Island in Holland. It took approximately 6 months to reconstruct the mill. The city erected a raised base rather than the mound of earth it had been set on in Vinkel so as to restore it to its original design when it stood in Krommenie. Once erected, the City of Holland celebrated as having been over 200 years old at the time.

In April 1965, the  windmill was formally dedicated on Windmill Island, a  site reclaimed from a swamp on the eastern end of Lake Macatawa. It is open from late April through early October.

When winds are favorable ( from the west), De Zwaan's  diameter blades are usually in motion.

In 2015, the City of Holland celebrated the 50th anniversary of De Zwaan being in Holland. In preparation for the celebration, De Zwaan's resident Miller and historian, Alisa Crawford, set out to author the only definitive book ever written about De Zwaan.  Alisa Crawford holds a master's degree in museum studies and is the only Dutch certified miller in the United States, an accreditation she earned after years of independent study while working for the City of Holland at De Zwaan. In seeking data about De Zwaan's original construction, Crawford learned that  the De Zwaan in Krommenie had been taken down in 1887, which was three years after De Zwaan had been relocated to Vinkel. She realized that there had, in fact, been at least two windmills in the Netherlands named De Zwaan.

Ultimately Crawford was able to prove the De Zwaan windmill moved to Holland, Michigan, had originally been erected in the city of Dordrecht in South Holland as a zaagmolen (sawmill) in 1833. The mill was converted to steam power in 1884 and its eight-sided body, cap, and blades become superfluous. At that point the Van Schayk family purchased it for relocation to Vinkel. They also purchased parts from a different mill, likely the Nooitgedacht (Never Thought) that had been built in 1800 in 's-Hertogenbosch (now Den Bosch), and dismantled in 1883.

This information led to the understanding that De Zwaan was about 70 years younger than the City of Holland was led to believe when it acquired the windmill in 1964 and was a hybrid mill built from the structure and components from two to three other mills. Crawford notes "that lineage is what makes De Zwaan unequivocally authentic. Windmills were and continue to be working machines. When they break, they are repaired. When the parts wear out, they are replaced.  When they became outmoded, they are repurposed."

There is, unfortunately, a lot of inaccurate information in newspapers published between 1964 and 2015 about the origins of De Zwaan. Additionally not all online sources have revised the original build date of De Zwaan.

National Register of Historic Places
After the publication of her book, De Zwaan: The True Story of America's Authentic Dutch Windmill, Alisa Crawford wrote the nomination of De Zwaan to the National Register of Historic Places on behalf of the City of Holland. The mill was listed on the National Register of Historic Places in 2018.

The City of Holland erected a State Historic Marker at De Zwaan in 2019. The text on side one reads: "In 1961 Castle Park resort owner Carter P. Brown proposed the idea of creating a public park with 'an authentic Dutch windmill,' a symbol of Holland's Dutch heritage. To do so, city officials needed permission from the Dutch government, which protects windmills as national monuments. Willard C. Wichers, Midwest director for the Netherlands Information Service, led negotiations with the Dutch over a three-year period. In June 1964 he traveled to the Netherlands to find a suitable mill and finalize arrangements to buy and move it. In Vinkel, North Brabant, stood a mill that had been built in 1884 using pieces from older Mills. Named De Zwaan (the Swan), it had been damaged during World War II and had deteriorated. Dutch officials allowed its sale but required that Dutch millwright Jan D. Medendorp supervise its relocation and restoration."

See also
Tulip Time

References

External links

Windmill Island Gardens - official site
About Holland PDF
Windmill marks 40 years in Holland
Windmill De Zwaan more than just a symbol of Holland City's roots

National Register of Historic Places in Ottawa County, Michigan
Dutch-American culture in Michigan
Buildings and structures in Holland, Michigan
Museums in Ottawa County, Michigan
Tourist attractions in Ottawa County, Michigan
Smock mills in the United States
Grinding mills in Michigan
Relocated buildings and structures in Michigan
Octagonal buildings in the United States
Wind power in Michigan
Buildings and structures completed in 1761
Mill museums in Michigan
Agricultural buildings and structures in Michigan
Windmills on the National Register of Historic Places

De Zwaan (windmill)


In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time. Energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another. For instance, chemical energy is converted to kinetic energy when a stick of dynamite explodes. If one adds up all forms of energy that were released in the explosion, such as the kinetic energy and potential energy of the pieces, as well as heat and sound, one will get the exact decrease of chemical energy in the combustion of the dynamite.

Classically, conservation of energy was distinct from conservation of mass. However, special relativity shows that mass is related to energy and vice versa by , the equation representing mass–energy equivalence, and science now takes the view that mass-energy as a whole is conserved. Theoretically, this implies that any object with mass can itself be converted to pure energy, and vice versa. However, this is believed to be possible only under the most extreme of physical conditions, such as likely existed in the universe very shortly after the Big Bang or when black holes emit Hawking radiation.

Given the stationary-action principle, conservation of energy can be rigorously proven by Noether's theorem as a consequence of continuous time translation symmetry; that is, from the fact that the laws of physics do not change over time.

A consequence of the law of conservation of energy is that a perpetual motion machine of the first kind cannot exist; that is to say, no system without an external energy supply can deliver an unlimited amount of energy to its surroundings. Depending on the definition of energy, conservation of energy can arguably be violated by general relativity on the cosmological scale.

History

Ancient philosophers as far back as Thales of Miletus  550 BCE had inklings of the conservation of some underlying substance of which everything is made. However, there is no particular reason to identify their theories with what we know today as "mass-energy" (for example, Thales thought it was water). Empedocles (490–430 BCE) wrote that in his universal system, composed of four roots (earth, air, water, fire), "nothing comes to be or perishes"; instead, these elements suffer continual rearrangement. Epicurus ( 350 BCE) on the other hand believed everything in the universe to be composed of indivisible units of matter—the ancient precursor to 'atoms'—and he too had some idea of the necessity of conservation, stating that "the sum total of things was always such as it is now, and such it will ever remain."

In 1605, Simon Stevin was able to solve a number of problems in statics based on the principle that perpetual motion was impossible.

In 1639, Galileo published his analysis of several situations—including the celebrated "interrupted pendulum"—which can be described (in modern language) as conservatively converting potential energy to kinetic energy and back again. Essentially, he pointed out that the height a moving body rises is equal to the height from which it falls, and used this observation to infer the idea of inertia. The remarkable aspect of this observation is that the height to which a moving body ascends on a frictionless surface does not depend on the shape of the surface.

In 1669, Christiaan Huygens published his laws of collision. Among the quantities he listed as being invariant before and after the collision of bodies were both the sum of their linear momenta as well as the sum of their kinetic energies. However, the difference between elastic and inelastic collision was not understood at the time. This led to the dispute among later researchers as to which of these conserved quantities was the more fundamental. In his Horologium Oscillatorium, he gave a much clearer statement regarding the height of ascent of a moving body, and connected this idea with the impossibility of perpetual motion. Huygens's study of the dynamics of pendulum motion was based on a single principle: that the center of gravity of a heavy object cannot lift itself.

Between 1676 and 1689, Gottfried Leibniz first attempted a mathematical formulation of the kind of energy that is associated with motion (kinetic energy). Using Huygens's work on collision, Leibniz noticed that in many mechanical systems (of several masses mi, each with velocity vi),

was conserved so long as the masses did not interact. He called this quantity the vis viva or living force of the system. The principle represents an accurate statement of the approximate conservation of kinetic energy in situations where there is no friction. Many physicists at that time, including Isaac Newton, held that the conservation of momentum, which holds even in systems with friction, as defined by the momentum:

was the conserved vis viva. It was later shown that both quantities are conserved simultaneously given the proper conditions, such as in an elastic collision.

In 1687, Isaac Newton published his Principia, which set out his laws of motion. It was organized around the concept of force and momentum. However, the researchers were quick to recognize that the principles set out in the book, while fine for point masses, were not sufficient to tackle the motions of rigid and fluid bodies. Some other principles were also required.

By the 1690s, Leibniz was arguing that conservation of vis viva and conservation of momentum undermined the then-popular philosophical doctrine of interactionist dualism. (During the 19th century, when conservation of energy was better understood, Leibniz's basic argument would gain widespread acceptance. Some modern scholars continue to champion specifically conservation-based attacks on dualism, while others subsume the argument into a more general argument about causal closure.)

The law of conservation of vis viva was championed by the father and son duo, Johann and Daniel Bernoulli. The former enunciated the principle of virtual work as used in statics in its full generality in 1715, while the latter based his Hydrodynamica, published in 1738, on this single vis viva conservation principle. Daniel's study of loss of vis viva of flowing water led him to formulate the Bernoulli's principle, which asserts the loss to be proportional to the change in hydrodynamic pressure. Daniel also formulated the notion of work and efficiency for hydraulic machines; and he gave a kinetic theory of gases, and linked the kinetic energy of gas molecules with the temperature of the gas.

This focus on the vis viva by the continental physicists eventually led to the discovery of stationarity principles governing mechanics, such as the D'Alembert's principle, Lagrangian, and Hamiltonian formulations of mechanics.

Émilie du Châtelet (1706–1749) proposed and tested the hypothesis of the conservation of total energy, as distinct from momentum. Inspired by the theories of Gottfried Leibniz, she repeated and publicized an experiment originally devised by Willem 's Gravesande in 1722 in which balls were dropped from different heights into a sheet of soft clay. Each ball's kinetic energy—as indicated by the quantity of material displaced—was shown to be proportional to the square of the velocity. The deformation of the clay was found to be directly proportional to the height from which the balls were dropped, equal to the initial potential energy. Some earlier workers, including Newton and Voltaire, had believed that "energy" was not distinct from momentum and therefore proportional to velocity. According to this understanding, the deformation of the clay should have been proportional to the square root of the height from which the balls were dropped. In classical physics, the correct formula is , where  is the kinetic energy of an object,  its mass and  its speed. On this basis, du Châtelet proposed that energy must always have the same dimensions in any form, which is necessary to be able to consider it in different forms (kinetic, potential, heat, ...).

Engineers such as John Smeaton, Peter Ewart, , Gustave-Adolphe Hirn, and Marc Seguin recognized that conservation of momentum alone was not adequate for practical calculation and made use of Leibniz's principle. The principle was also championed by some chemists such as William Hyde Wollaston. Academics such as John Playfair were quick to point out that kinetic energy is clearly not conserved. This is obvious to a modern analysis based on the second law of thermodynamics, but in the 18th and 19th centuries, the fate of the lost energy was still unknown.

Gradually it came to be suspected that the heat inevitably generated by motion under friction was another form of vis viva. In 1783, Antoine Lavoisier and Pierre-Simon Laplace reviewed the two competing theories of vis viva and caloric theory. Count Rumford's 1798 observations of heat generation during the boring of cannons added more weight to the view that mechanical motion could be converted into heat and (that it was important) that the conversion was quantitative and could be predicted (allowing for a universal conversion constant between kinetic energy and heat). Vis viva then started to be known as energy, after the term was first used in that sense by Thomas Young in 1807.

The recalibration of vis viva to

which can be understood as converting kinetic energy to work, was largely the result of Gaspard-Gustave Coriolis and Jean-Victor Poncelet over the period 1819–1839. The former called the quantity quantité de travail (quantity of work) and the latter, travail mécanique (mechanical work), and both championed its use in engineering calculations.

In the paper Über die Natur der Wärme (German "On the Nature of Heat/Warmth"), published in the  in 1837, Karl Friedrich Mohr gave one of the earliest general statements of the doctrine of the conservation of energy: "besides the 54 known chemical elements there is in the physical world one agent only, and this is called Kraft [energy or work]. It may appear, according to circumstances, as motion, chemical affinity, cohesion, electricity, light and magnetism; and from any one of these forms it can be transformed into any of the others."

Mechanical equivalent of heat
A key stage in the development of the modern conservation principle was the demonstration of the mechanical equivalent of heat. The caloric theory maintained that heat could neither be created nor destroyed, whereas conservation of energy entails the contrary principle that heat and mechanical work are interchangeable.

In the middle of the eighteenth century, Mikhail Lomonosov, a Russian scientist, postulated his corpusculo-kinetic theory of heat, which rejected the idea of a caloric. Through the results of empirical studies, Lomonosov came to the conclusion that heat was not transferred through the particles of the caloric fluid.

In 1798, Count Rumford (Benjamin Thompson) performed measurements of the frictional heat generated in boring cannons and developed the idea that heat is a form of kinetic energy; his measurements refuted caloric theory, but were imprecise enough to leave room for doubt.

The mechanical equivalence principle was first stated in its modern form by the German surgeon Julius Robert von Mayer in 1842. Mayer reached his conclusion on a voyage to the Dutch East Indies, where he found that his patients' blood was a deeper red because they were consuming less oxygen, and therefore less energy, to maintain their body temperature in the hotter climate. He discovered that heat and mechanical work were both forms of energy, and in 1845, after improving his knowledge of physics, he published a monograph that stated a quantitative relationship between them.

Meanwhile, in 1843, James Prescott Joule independently discovered the mechanical equivalent in a series of experiments. In the most famous, now called the "Joule apparatus", a descending weight attached to a string caused a paddle immersed in water to rotate.  He showed that the gravitational potential energy lost by the weight in descending was equal to the internal energy gained by the water through friction with the paddle.

Over the period 1840–1843, similar work was carried out by engineer Ludwig A. Colding, although it was little known outside his native Denmark.

Both Joule's and Mayer's work suffered from resistance and neglect but it was Joule's that eventually drew the wider recognition.

In 1844, William Robert Grove postulated a relationship between mechanics, heat, light, electricity, and magnetism by treating them all as manifestations of a single "force" (energy in modern terms). In 1846, Grove published his theories in his book The Correlation of Physical Forces. In 1847, drawing on the earlier work of Joule, Sadi Carnot, and Émile Clapeyron, Hermann von Helmholtz arrived at conclusions similar to Grove's and published his theories in his book Über die Erhaltung der Kraft (On the Conservation of Force, 1847). The general modern acceptance of the principle stems from this publication.

In 1850, William Rankine first used the phrase the law of the conservation of energy for the principle.

In 1877, Peter Guthrie Tait claimed that the principle originated with Sir Isaac Newton, based on a creative reading of propositions 40 and 41 of the Philosophiae Naturalis Principia Mathematica. This is now regarded as an example of Whig history.

Mass–energy equivalence

Matter is composed of atoms and what makes up atoms. Matter has intrinsic or rest mass. In the limited range of recognized experience of the nineteenth century, it was found that such rest mass is conserved. Einstein's 1905 theory of special relativity showed that rest mass corresponds to an equivalent amount of rest energy. This means that rest mass can be converted to or from equivalent amounts of (non-material) forms of energy, for example, kinetic energy, potential energy, and electromagnetic radiant energy. When this happens, as recognized in twentieth-century experience, rest mass is not conserved, unlike the total mass or total energy. All forms of energy contribute to the total mass and total energy.

For example, an electron and a positron each have rest mass.  They can perish together, converting their combined rest energy into photons which have electromagnetic radiant energy but no rest mass.  If this occurs within an isolated system that does not release the photons or their energy into the external surroundings, then neither the total mass nor the total energy of the system will change.  The produced electromagnetic radiant energy contributes just as much to the inertia (and to any weight) of the system as did the rest mass of the electron and positron before their demise. Likewise, non-material forms of energy can perish into matter, which has rest mass.

Thus, conservation of energy (total, including material or rest energy) and conservation of mass (total, not just rest) are one (equivalent) law. In the 18th century, these had appeared as two seemingly-distinct laws.

Conservation of energy in beta decay

The discovery in 1911 that electrons emitted in beta decay have a continuous rather than a discrete spectrum appeared to contradict conservation of energy, under the then-current assumption that beta decay is the simple emission of an electron from a nucleus. This problem was eventually resolved in 1933 by Enrico Fermi who proposed the correct description of beta-decay as the emission of both an electron and an antineutrino, which carries away the apparently missing energy.

First law of thermodynamics

For a closed thermodynamic system, the first law of thermodynamics may be stated as:

, or equivalently,

where  is the quantity of energy added to the system by a heating process,  is the quantity of energy lost by the system due to work done by the system on its surroundings, and  is the change in the internal energy of the system.

The δ's before the heat and work terms are used to indicate that they describe an increment of energy which is to be interpreted somewhat differently than the  increment of internal energy (see Inexact differential). Work and heat refer to kinds of process which add or subtract energy to or from a system, while the internal energy  is a property of a particular state of the system when it is in unchanging thermodynamic equilibrium. Thus the term "heat energy" for  means "that amount of energy added as a result of heating" rather than referring to a particular form of energy. Likewise, the term "work energy" for  means "that amount of energy lost as a result of work". Thus one can state the amount of internal energy possessed by a thermodynamic system that one knows is presently in a given state, but one cannot tell, just from knowledge of the given present state, how much energy has in the past flowed into or out of the system as a result of its being heated or cooled, nor as a result of work being performed on or by the system.

Entropy is a function of the state of a system which tells of limitations of the possibility of conversion of heat into work.

For a simple compressible system, the work performed by the system may be written:

where  is the pressure and  is a small change in the volume of the system, each of which are system variables. In the fictive case in which the process is idealized and infinitely slow, so as to be called quasi-static, and regarded as reversible, the heat being transferred from a source with temperature infinitesimally above the system temperature, the heat energy may be written

where  is the temperature and  is a small change in the entropy of the system. Temperature and entropy are variables of the state of a system.

If an open system (in which mass may be exchanged with the environment) has several walls such that the mass transfer is through rigid walls separate from the heat and work transfers, then the first law may be written as

where  is the added mass of species  and  is the corresponding enthalpy per unit mass. Note that generally  in this case, as matter carries its own entropy. Instead, , where  is the entropy per unit mass of type , from which we recover the fundamental thermodynamic relation

because the chemical potential  is the partial molar Gibbs free energy of species  and the Gibbs free energy .

Noether's theorem

The conservation of energy is a common feature in many physical theories. From a mathematical point of view it is understood as a consequence of Noether's theorem, developed by Emmy Noether in 1915 and first published in 1918. In any physical theory that obeys the stationary-action principle, the theorem states that every continuous symmetry has an associated conserved quantity; if the theory's symmetry is time invariance, then the conserved quantity is called "energy". The energy conservation law is a consequence of the shift symmetry of time; energy conservation is implied by the empirical fact that the laws of physics do not change with time itself. Philosophically this can be stated as "nothing depends on time per se". In other words, if the physical system is invariant under the continuous symmetry of time translation, then its energy (which is the canonical conjugate quantity to time) is conserved.  Conversely, systems that are not invariant under shifts in time (e.g. systems with time-dependent potential energy) do not exhibit conservation of energy – unless we consider them to exchange energy with another, an external system so that the theory of the enlarged system becomes time-invariant again. Conservation of energy for finite systems is valid in physical theories such as special relativity and quantum theory (including QED) in the flat space-time.

Special relativity
With the discovery of special relativity by Henri Poincaré and Albert Einstein, the energy was proposed to be a component of an energy-momentum 4-vector. Each of the four components (one of energy and three of momentum) of this vector is separately conserved across time, in any closed system, as seen from any given inertial reference frame. Also conserved is the vector length (Minkowski norm), which is the rest mass for single particles, and the invariant mass for systems of particles (where momenta and energy are separately summed before the length is calculated).

The relativistic energy of a single massive particle contains a term related to its rest mass in addition to its kinetic energy of motion. In the limit of zero kinetic energy (or equivalently in the rest frame) of a massive particle, or else in the center of momentum frame for objects or systems which retain kinetic energy, the total energy of a particle or object (including internal kinetic energy in systems) is proportional to the rest mass or invariant mass, as described by the famous equation .

Thus, the rule of conservation of energy over time in special relativity continues to hold, so long as the reference frame of the observer is unchanged. This applies to the total energy of systems, although different observers disagree as to the energy value. Also conserved, and invariant to all observers, is the invariant mass, which is the minimal system mass and energy that can be seen by any observer, and which is defined by the energy–momentum relation.

General relativity
General relativity introduces new phenomena. In an expanding universe, photons spontaneously redshift and tethers spontaneously gain tension; if vacuum energy is positive, the total vacuum energy of the universe appears to spontaneously increase as the volume of space increases. Some scholars claim that energy is no longer meaningfully conserved in any identifiable form.

John Baez's view is that energy–momentum conservation is not well-defined except in certain special cases. Energy-momentum is typically expressed with the aid of a stress–energy–momentum pseudotensor. However, since pseudotensors are not tensors, they do not transform cleanly between reference frames. If the metric under consideration is static (that is, does not change with time) or asymptotically flat (that is, at an infinite distance away spacetime looks empty), then energy conservation holds without major pitfalls. In practice, some metrics, notably the Friedmann–Lemaître–Robertson–Walker metric that appears to govern the universe, do not satisfy these constraints and energy conservation is not well defined. Besides being dependent on the coordinate system, pseudotensor energy is dependent on the type of pseudotensor in use; for example, the energy exterior to a Kerr–Newman black hole is twice as large when calculated from Møller's pseudotensor as it is when calculated using the Einstein pseudotensor.

For asymptotically flat universes, Einstein and others salvage conservation of energy by introducing a specific global gravitational potential energy that cancels out mass-energy changes triggered by spacetime expansion or contraction. This global energy has no well-defined density and cannot technically be applied to a non-asymptotically flat universe; however, for practical purposes this can be finessed, and so by this view, energy is conserved in our universe. Alan Guth even famously stated that the universe might be "the ultimate free lunch", and theorized that, when accounting for gravitational potential energy, the net energy of the Universe is zero.

Quantum theory
In quantum mechanics, the energy of a quantum system is described by a self-adjoint (or Hermitian) operator called the Hamiltonian, which acts on the Hilbert space (or a space of wave functions) of the system. If the Hamiltonian is a time-independent operator, emergence probability of the measurement result does not change in time over the evolution of the system. Thus the expectation value of energy is also time independent. The local energy conservation in quantum field theory is ensured by the quantum Noether's theorem for the energy-momentum tensor operator. Thus energy is conserved by the normal unitary evolution of a quantum system.

However, when the non-unitary Born rule is applied, the system's energy is measured with an energy that can be below or above the expectation value, if the system was not in an energy eigenstate. (For macroscopic systems, this effect is usually too small to measure.) The disposition of this energy gap is not well-understood; some physicists believe that the energy is transferred to or from the macroscopic environment in the course of the measurement process, while others believe that the observable energy is only conserved "on average". No experiment has been confirmed as definitive evidence of violations of the conservation of energy principle in quantum mechanics, but that doesn't rule out that some newer experiments, as proposed, may find evidence of violations of the conservation of energy principle in quantum mechanics.

Status
In the context of perpetual motion machines such as the Orbo, Professor Eric Ash has argued at the BBC: "Denying [conservation of energy] would undermine not just little bits of science - the whole edifice would be no more. All of the technology on which we built the modern world would lie in ruins." It is because of conservation of energy that "we know - without having to examine details of a particular device - that Orbo cannot work."

Energy conservation has been a foundational physical principle for about two hundred years. From the point of view of modern general relativity, the lab environment can be well approximated by Minkowski spacetime, where energy is exactly conserved. The entire Earth can be well approximated by the Schwarzschild metric, where again energy is exactly conserved. Given all the experimental evidence, any new theory (such as quantum gravity), in order to be successful, will have to explain why energy has appeared to always be exactly conserved in terrestrial experiments. In some speculative theories, corrections to quantum mechanics are too small to be detected at anywhere near the current TeV level accessible through particle accelerators. Doubly special relativity models may argue for a breakdown in energy-momentum conservation for sufficiently energetic particles; such models are constrained by observations that cosmic rays appear to travel for billions of years without displaying anomalous non-conservation behavior. Some interpretations of quantum mechanics claim that observed energy tends to increase when the Born rule is applied due to localization of the wave function. If true, objects could be expected to spontaneously heat up; thus, such models are constrained by observations of large, cool astronomical objects as well as the observation of (often supercooled) laboratory experiments.

See also

 Energy quality
 Energy transformation
 Lagrangian mechanics
 Laws of thermodynamics
 Zero-energy universe

References

Bibliography

Modern accounts
 Goldstein, Martin, and Inge F., (1993). The Refrigerator and the Universe. Harvard Univ. Press. A gentle introduction.

 Stenger, Victor J. (2000). Timeless Reality. Prometheus Books. Especially chpt. 12. Nontechnical.

History of ideas

 Kuhn, T.S. (1957) "Energy conservation as an example of simultaneous discovery", in M. Clagett (ed.) Critical Problems in the History of Science pp.321–56

 , Chapter 8, "Energy and Thermo-dynamics"

External links
 MISN-0-158 The First Law of Thermodynamics (PDF file) by Jerzy Borysowicz for Project PHYSNET.

Energy (physics)
Laws of thermodynamics
Conservation laws
Articles containing video clips

Conservation of energy


William Alvin Bowen (May 15, 1877–September 18, 1937) was an American attorney who wrote several children's books in the 1920s. His most notable work was The Old Tobacco Shop, a fantasy novel that was one runner-up for the inaugural Newbery Medal in 1922.

Bowen was born in Baltimore, Maryland, earned a Bachelor of Laws degree from the University of Maryland in 1898, and worked in his father's law office until 1904, when he moved to Los Angeles. There he was a member of the Olympic Committee as attorney for the 1932 Summer Olympics. He was also a member of the California and Southern California Historical Societies.

Bowen's first children's book was The Enchanted Forest, a fantasy novel published by Macmillan late in 1920. His second was The Old Tobacco Shop, one year later.

Works

 The Enchanted Forest, illustrated by Maud and Miska Petersham (The Macmillan Company, 1920)
 The Old Tobacco Shop: A True Account of What Befell a Little Boy in Search of Adventure, illus. Reginald Birch (Macmillan, Nov 1921)
 Solario the Tailor: His Tales of the Magic Doublet, illus. J. Ormsbee (Macmillan, Sep 1922) – sequel to The Enchanted Forest
 Merrimeg, illus. Emma Brock (Macmillan, 1923),
 Philip and the Faun, illus. N. Choate (Little, Brown and Company, Sep 1926)
 Gossip from the Sixteenth Century (Los Angeles: The Zamorano Club, 1938),

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External links

1877 births
1937 deaths
American children's writers
American fantasy writers
California lawyers
Newbery Honor winners
20th-century American writers
Writers from California

William Bowen (author)