University of Colorado Boulder
The University of Colorado Boulder is a public research university located in Boulder, United States. It is the flagship university of the University of Colorado system and was founded five months before Colorado was admitted to the Union in 1876. In 2015, the university comprised nine colleges and schools and offered over 150 academic programs and enrolled 17,000 students. Twelve Nobel Laureates, nine MacArthur Fellows, 20 astronauts have been affiliated with CU Boulder as students, researchers, or faculty members in its history; the university received nearly $454 million in sponsored research in 2010 to fund programs like the Laboratory for Atmospheric and Space Physics, JILA. The Colorado Buffaloes compete in 17 varsity sports and are members of the NCAA Division I Pac-12 Conference; the Buffaloes have won 28 national championships: 20 in skiing, seven total in men's and women's cross country, one in football. 900 students participate in 34 intercollegiate club sports annually as well. On March 14, 1876, the Colorado territorial legislature passed an amendment to the state constitution that provided money for the establishment of the University of Colorado in Boulder, the Colorado School of Mines in Golden, the Colorado Agricultural College in Fort Collins.
Two cities competed for the site of the University of Colorado: Cañon City. The consolation prize for the losing city was to be home of the new Colorado State Prison. Cañon City was at a disadvantage as it was the home of the Colorado Territorial Prison; the cornerstone of the building that became Old Main was laid on September 20, 1875. The doors of the university opened on September 5, 1877. At the time, there were few high schools in the state that could adequately prepare students for university work, so in addition to the University, a preparatory school was formed on campus. In the fall of 1877, the student body consisted of 15 students in the college proper and 50 students in the preparatory school. There were 38 men and 27 women, their ages ranged from 12–23 years. During World War II, Colorado was one of 131 colleges and universities nationally that took part in the V-12 Navy College Training Program which offered students a path to a navy commission; the main CU Boulder campus is located south of the Pearl Street Mall and east of Chautauqua Auditorium.
It consists of residential buildings as well as research facilities. The East Campus is about a quarter mile from the main campus and is composed of athletic fields and research buildings. CU Boulder's distinctive architecture style, known as Tuscan Vernacular Revival, was designed by architect Charles Klauder; the oldest buildings, such as Old Main and Macky Auditorium, were in the Collegiate Gothic style of many East Coast schools, Klauder's initial plans for the university's new buildings were in the same style. A month or so after approval, Klauder updated his design by sketching in a new wrap of rough, textured sandstone walls with sloping, multi-leveled red-tiled roofs and Indiana limestone trim; this formed the basis of a unified style, used in the design of fifteen other buildings between 1921 and 1939 and still followed on the campus to this day. The sandstone used in the construction of nearly all the buildings on campus was selected from a variety of Front Range mountain quarries.
In 2011, Travel+Leisure named the Boulder campus one of the most beautiful college campuses in the United States. Freshmen and others attending the University of Colorado Boulder have an option of 24 on- and off-campus residence halls. Residence halls have 17 varieties of room types from singles to four-person rooms and others with apartment style amenities. There are several communities of residence halls located throughout the campus, as well as in a separate area called Williams Village, located 1.5 miles off of main campus. There is a free bus service that transports students to main campus from Williams Village and vice versa; the University offers Residential Academic Programs in many of its Residence Halls. RAPs provide students with in-dorm classes tailored to academic interests; the Engineering Center on the North-East side of campus houses the nation's largest geotechnical centrifuge as well as ion-implantation and microwave-propagation facilities, spectrometers and other microscopes, a structural analysis facility.
Until 1903, the library collection was housed with the rest of the school in Old Main. The growing size of the library required a move, as the weight of the books was causing physical damage to the floor; the cornerstone for the first separate library building was laid in January 1903, the building was opened in January 1904. When the new Norlin Library opened in 1940, the old library turned over to the Theatre department, was converted into classrooms and a theatre. Norlin Library was the last building to be designed by Klauder. There are two inscriptions on the western face of the building. Both were composed by President Norlin; the larger inscription reads "Who knows only his own generation remains always a child," based on a Cicero quotation, while the smaller inscription on the marble just over the door reads "Enter here the timeless fellowship of the human spirit." Macky Auditorium is a large building on the north edge of the University of Colorado campus, near 17th Street and University Avenue, which plays host to various talks and musical performances.
Andrew J. Macky was a prominent businessman involved with the town of Boulder in the late 19th century. Macky
Electrical engineering is a professional engineering discipline that deals with the study and application of electricity and electromagnetism. This field first became an identifiable occupation in the half of the 19th century after commercialization of the electric telegraph, the telephone, electric power distribution and use. Subsequently and recording media made electronics part of daily life; the invention of the transistor, the integrated circuit, brought down the cost of electronics to the point they can be used in any household object. Electrical engineering has now divided into a wide range of fields including electronics, digital computers, computer engineering, power engineering, telecommunications, control systems, radio-frequency engineering, signal processing and microelectronics. Many of these disciplines overlap with other engineering branches, spanning a huge number of specializations such as hardware engineering, power electronics and waves, microwave engineering, electrochemistry, renewable energies, electrical materials science, much more.
See glossary of electrical and electronics engineering. Electrical engineers hold a degree in electrical engineering or electronic engineering. Practising engineers may be members of a professional body; such bodies include the Institute of Electrical and Electronics Engineers and the Institution of Engineering and Technology. Electrical engineers work in a wide range of industries and the skills required are variable; these range from basic circuit theory to the management skills required of a project manager. The tools and equipment that an individual engineer may need are variable, ranging from a simple voltmeter to a top end analyzer to sophisticated design and manufacturing software. Electricity has been a subject of scientific interest since at least the early 17th century. William Gilbert was a prominent early electrical scientist, was the first to draw a clear distinction between magnetism and static electricity, he is credited with establishing the term "electricity". He designed the versorium: a device that detects the presence of statically charged objects.
In 1762 Swedish professor Johan Carl Wilcke invented a device named electrophorus that produced a static electric charge. By 1800 Alessandro Volta had developed the voltaic pile, a forerunner of the electric battery In the 19th century, research into the subject started to intensify. Notable developments in this century include the work of Hans Christian Ørsted who discovered in 1820 that an electric current produces a magnetic field that will deflect a compass needle, of William Sturgeon who, in 1825 invented the electromagnet, of Joseph Henry and Edward Davy who invented the electrical relay in 1835, of Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in a conductor, of Michael Faraday, of James Clerk Maxwell, who in 1873 published a unified theory of electricity and magnetism in his treatise Electricity and Magnetism. In 1782 Georges-Louis Le Sage developed and presented in Berlin the world's first form of electric telegraphy, using 24 different wires, one for each letter of the alphabet.
This telegraph connected two rooms. It was an electrostatic telegraph. In 1795, Francisco Salva Campillo proposed an electrostatic telegraph system. Between 1803-1804, he worked on electrical telegraphy and in 1804, he presented his report at the Royal Academy of Natural Sciences and Arts of Barcelona. Salva’s electrolyte telegraph system was innovative though it was influenced by and based upon two new discoveries made in Europe in 1800 – Alessandro Volta’s electric battery for generating an electric current and William Nicholson and Anthony Carlyle’s electrolysis of water. Electrical telegraphy may be considered the first example of electrical engineering. Electrical engineering became a profession in the 19th century. Practitioners had created a global electric telegraph network and the first professional electrical engineering institutions were founded in the UK and USA to support the new discipline. Francis Ronalds created an electric telegraph system in 1816 and documented his vision of how the world could be transformed by electricity.
Over 50 years he joined the new Society of Telegraph Engineers where he was regarded by other members as the first of their cohort. By the end of the 19th century, the world had been forever changed by the rapid communication made possible by the engineering development of land-lines, submarine cables, from about 1890, wireless telegraphy. Practical applications and advances in such fields created an increasing need for standardised units of measure, they led to the international standardization of the units volt, coulomb, ohm and henry. This was achieved at an international conference in Chicago in 1893; the publication of these standards formed the basis of future advances in standardisation in various industries, in many countries, the definitions were recognized in relevant legislation. During these years, the study of electricity was considered to be a subfield of physics since the early electrical technology was considered electromechanical in nature; the Technische Universität Darmstadt founded the world's first department of electrical engineering in 1882.
The first electrical engineering degree program was started at Massachusetts Institute of Technology in the physics department
Fantasia (1940 film)
Fantasia is a 1940 American animated film produced by Walt Disney and released by Walt Disney Productions. With story direction by Joe Grant and Dick Huemer, production supervision by Ben Sharpsteen, it is the third Disney animated feature film; the film consists of eight animated segments set to pieces of classical music conducted by Leopold Stokowski, seven of which are performed by the Philadelphia Orchestra. Music critic and composer Deems Taylor acts as the film's Master of Ceremonies, providing a live-action introduction to each animated segment. Disney settled on the film's concept as work neared completion on The Sorcerer's Apprentice, an elaborate Silly Symphonies short designed as a comeback role for Mickey Mouse, who had declined in popularity; as production costs grew higher than what it could earn, Disney decided to include the short in a feature-length film with other segments set to classical pieces. The soundtrack was recorded using multiple audio channels and reproduced with Fantasound, a pioneering sound reproduction system that made Fantasia the first commercial film shown in stereophonic sound.
Fantasia was first released as a theatrical roadshow held in thirteen U. S. cities from November 13, 1940. While acclaimed by critics, it was unable to make a profit due to World War II cutting off distribution to the European market, the film's high production costs, the expense of leasing theatres and installing the Fantasound equipment for the roadshow presentations; the film was subsequently reissued multiple times with its original footage and audio being deleted, modified, or restored in each version. Fantasia is the 23rd highest-grossing film of all time in the U. S. when adjusted for inflation. The Fantasia franchise has grown to include video games, Disneyland attractions, a live concert. A sequel, Fantasia 2000, co-produced by Roy E. Disney, was released in 1999. Fantasia has grown in reputation over the years and is now acclaimed. Fantasia opens with live action scenes of members of an orchestra gathering against a blue background and tuning their instruments in half-light, half-shadow.
Master of ceremonies Deems Taylor introduces the program. Toccata and Fugue in D Minor by Johann Sebastian Bach. Live-action shots of the orchestra illuminated in blue and gold, backed by superimposed shadows, fade into abstract patterns. Animated lines and cloud formations reflect the sound and rhythms of the music. Nutcracker Suite by Pyotr Ilyich Tchaikovsky. Selections from the ballet suite underscore scenes depicting the changing of the seasons from summer to autumn to winter. A variety of dances are presented with fairies, flowers and leaves, including "Dance of the Sugar Plum Fairy", "Chinese Dance", "Arabian Dance", "Russian Dance", "Dance of the Flutes" and "Waltz of the Flowers"; the Sorcerer's Apprentice by Paul Dukas. Based on Goethe's 1797 poem "Der Zauberlehrling". Mickey Mouse, the young apprentice of the sorcerer Yen Sid, attempts some of his master's magic tricks but does not know how to control them. Rite of Spring by Igor Stravinsky. A visual history of the Earth's beginnings is depicted to selected sections of the ballet score.
The sequence progresses from the planet's formation to the first living creatures, followed by the reign and extinction of the dinosaurs. Intermission/Meet the Soundtrack: The orchestra musicians depart and the Fantasia title card is revealed. After the intermission there is a brief jam session of jazz music led by a clarinettist as the orchestra members return. A humorously stylized demonstration of how sound is rendered on film is shown. An animated sound track "character" a straight white line, changes into different shapes and colors based on the sounds played; the Pastoral Symphony by Ludwig van Beethoven. A mythical Greco-Roman world of colorful centaurs and "centaurettes", cupids and other figures from classical mythology is portrayed to Beethoven's music. A gathering for a festival to honor Bacchus, the god of wine, is interrupted by Zeus, who creates a storm and directs Vulcan to forge lightning bolts for him to throw at the attendees. Dance of the Hours by Amilcare Ponchielli. A comic ballet in four sections: Madame Upanova and her ostriches.
The finale finds all of the characters dancing together until their palace collapses. Night on Bald Mountain by Modest Mussorgsky and Ave Maria by Franz Schubert. At midnight the devil Chernabog awakes and summons evil spirits and restless souls from their graves to Bald Mountain; the spirits dance and fly through the air until driven back by the sound of an Angelus bell as night fades into dawn. A chorus is heard singing Ave Maria as a line of robed monks is depicted walking with lighted torches through a forest and into the ruins of a cathedral. In 1936, Walt Disney felt that the Disney studio's star character Mickey Mouse needed a boost in popularity, he decided to feature the mouse in The Sorcerer's Apprentice, a deluxe cartoon short based on the poem written by Johann Wolfgang von Goethe and set to the orchestral piece by Paul Dukas inspired by the original tale. The concept of matching animation to classical music was used as early as 1928 in Disney's cartoon series, the Silly Symphonies, but he wanted to go beyond the usual slapstick, produce shorts where "sheer fantasy unfolds... action controlled by a musical pattern has great charm in the realm of unreality."
Upon receiving the rights to use the music by the end of Ju
United States Constitution
The United States Constitution is the supreme law of the United States. The Constitution comprising seven articles, delineates the national frame of government, its first three articles embody the doctrine of the separation of powers, whereby the federal government is divided into three branches: the legislative, consisting of the bicameral Congress. Articles Four and Six embody concepts of federalism, describing the rights and responsibilities of state governments, the states in relationship to the federal government, the shared process of constitutional amendment. Article Seven establishes the procedure subsequently used by the thirteen States to ratify it, it is regarded as the oldest codified national constitution in force. Since the Constitution came into force in 1789, it has been amended 27 times, including an amendment to repeal a previous one, in order to meet the needs of a nation that has profoundly changed since the eighteenth century. In general, the first ten amendments, known collectively as the Bill of Rights, offer specific protections of individual liberty and justice and place restrictions on the powers of government.
The majority of the seventeen amendments expand individual civil rights protections. Others modify government processes and procedures. Amendments to the United States Constitution, unlike ones made to many constitutions worldwide, are appended to the document. All four pages of the original U. S. Constitution are written on parchment. According to the United States Senate: "The Constitution's first three words—We the People—affirm that the government of the United States exists to serve its citizens. For over two centuries the Constitution has remained in force because its framers wisely separated and balanced governmental powers to safeguard the interests of majority rule and minority rights, of liberty and equality, of the federal and state governments."The first permanent constitution of its kind, adopted by the people's representatives for an expansive nation, it is interpreted and implemented by a large body of constitutional law, has influenced the constitutions of other nations. From September 5, 1774, to March 1, 1781, the Continental Congress functioned as the provisional government of the United States.
Delegates to the First and the Second Continental Congress were chosen through the action of committees of correspondence in various colonies rather than through the colonial or state legislatures. In no formal sense was it a gathering representative of existing colonial governments; the process of selecting the delegates for the First and Second Continental Congresses underscores the revolutionary role of the people of the colonies in establishing a central governing body. Endowed by the people collectively, the Continental Congress alone possessed those attributes of external sovereignty which entitled it to be called a state in the international sense, while the separate states, exercising a limited or internal sovereignty, may rightly be considered a creation of the Continental Congress, which preceded them and brought them into being; the Articles of Confederation and Perpetual Union was the first constitution of the United States. It was drafted by the Second Continental Congress from mid-1776 through late 1777, ratification by all 13 states was completed by early 1781.
The Articles of Confederation gave little power to the central government. The Confederation Congress lacked enforcement powers. Implementation of most decisions, including modifications to the Articles, required unanimous approval of all thirteen state legislatures. Although, in a way, the Congressional powers in Article 9 made the "league of states as cohesive and strong as any similar sort of republican confederation in history", the chief problem was, in the words of George Washington, "no money"; the Continental Congress could print money but it was worthless. Congress couldn't pay it back. No state paid all their U. S. taxes. Some few paid an amount equal to interest on the national debt no more. No interest was paid on debt owed foreign governments. By 1786, the United States would default on outstanding debts. Internationally, the United States had little ability to defend its sovereignty. Most of the troops in the 625-man United States Army were deployed facing – but not threatening – British forts on American soil.
They had not been paid. Spain closed New Orleans to American commerce. S. officials protested, but to no effect. Barbary pirates began seizing American ships of commerce. If any military crisis required action, the Congress had no credit or taxing power to finance a response. Domestically, the Articles of Confederation was failing to bring unity to the diverse sentiments and interests of the various states. Although the Treaty of Paris was signed between Great Britain and the U. S. and named each of the American states, various states proceeded blithely to violate it. New York and South Carolina prosecuted Loyalists for wartime activity and redistributed their lands. Individual state legislatures independently laid embargoes, negotiated directly with foreign authorities, raised armies, and
Martial law is the imposition of direct military control of normal civilian functions of government in response to a temporary emergency such as invasion or major disaster, or in an occupied territory. Martial law can be used by governments to enforce their rule over the public, as seen in multiple countries listed below; such incidents may occur after a coup d'état. Martial law may be declared in cases of major natural disasters. Martial law has been imposed during conflicts, in cases of occupations, where the absence of any other civil government provides for an unstable population. Examples of this form of military rule include post World War II reconstruction in Germany and Japan, the recovery and reconstruction of the former Confederate States of America during Reconstruction Era in the United States of America following the American Civil War, German occupation of northern France between 1871 and 1873 after the Treaty of Frankfurt ended the Franco-Prussian War; the imposition of martial law accompanies curfews.
Civilians defying martial law may be subjected to military tribunal. The Black War was a period of violent conflict between British colonists and Aboriginal Australians in Tasmania from the mid-1820s to 1832. With an escalation of violence in the late 1820s, Lieutenant-Governor George Arthur declared martial law in November 1828—effectively providing legal immunity for killing Aboriginal people, it would remain in force for more than three years, the longest period of martial law in Australian history. Brunei has been under a martial law since a rebellion occurred on 8 December 1962 known as the Brunei Revolt and was put down by British troops from Singapore; the Sultan of Brunei, Sultan Haji Hassanal Bolkiah Mu'izzaddin Waddaulah, is presently the head of state and the Minister of Defense and Commander in Chief of Royal Brunei Armed Forces The War Measures Act was a Government of Canada statute that allowed the government to assume sweeping emergency powers, stopping short of martial law, i.e. the military does not administer justice, which remains in the hands of the courts.
The Act has been invoked three times: During World War I, World War II, the October Crisis of 1970. In 1988, the War Measures Act was replaced by the Emergencies Act. During the colonial era, martial law was proclaimed and applied in the territory of the Province of Quebec during the invasion of Canada by the army of the American Continental Congress in 1775–1776, it was applied twice in the territory of Lower Canada during the 1837–1838 insurrections. On December 5, following the events of November 1837, martial law was proclaimed in the district of Montréal by Governor Gosford, without the support of the Legislative Assembly in the Parliament of Lower Canada, it was imposed until April 27, 1838. Martial law was proclaimed a second time on November 4, 1838, this time by acting Governor John Colborne, was applied in the district of Montreal until August 24, 1839. In Egypt, a State of Emergency has been in effect continuously since 1967. Following the assassination of President Anwar el-Sadat in 1981, a state of emergency was declared.
Egypt has been under state of emergency since. The legislation was extended in 2003 and were due to expire at the end of May 2006, but after the Dahab bombings in April of that year, state of emergency was renewed for another two years. In May 2008 there was a further extension to June 2010. In May 2010, the state of emergency was further extended, albeit with a promise from the government to be applied only to'Terrorism and Drugs' suspects. A State of Emergency gives military courts the power to try civilians and allows the government to detain for renewable 45-day periods and without court orders anyone deemed to be threatening state security. Public demonstrations are banned under the legislation. On 10 February 2011, the ex-president of Egypt, Hosni Mubarak, promised the deletion of the relevant constitutional article that gives legitimacy to State of Emergency in an attempt to please the mass number of protesters that demanded him to resign. On 11 February 2011, the president stepped down and the vice president Omar Suleiman de facto introduced the country to martial law when transferring all civilian powers from the presidential institution to the military institution.
It meant that the presidential executive powers, the parliamentary legislative powers and the judicial powers all transferred directly into the military system which may delegate powers back and forth to any civilian institution within its territory. The military issued in its third announcement the "end of the State of Emergency as soon as order is restored in Egypt". Before martial law, the Egyptian parliament under the constitution had the civilian power to declare a State of Emergency; when in martial law, the military gained all powers of the state, including to dissolve the parliament and suspend the constitution as it did in its fifth announcement. Under martial law, the only legal framework within the Egyptian territory is the numbered announcements from the military; these announcements c
Electronic test equipment
Electronic test equipment is used to create signals and capture responses from electronic devices under test. In this way, the proper operation of the DUT can be proven or faults in the device can be traced. Use of electronic test equipment is essential to any serious work on electronics systems. Practical electronics engineering and assembly requires the use of many different kinds of electronic test equipment ranging from the simple and inexpensive to complex and sophisticated such as automatic test equipment. ATE includes many of these instruments in real and simulated forms. More advanced test gear is necessary when developing circuits and systems than is needed when doing production testing or when troubleshooting existing production units in the field; the following items are used for basic measurement of voltages and components in the circuit under test. Voltmeter Ohmmeter Ammeter, e.g. Galvanometer or Milliameter Multimeter e.g. VOM or DMM LCR meter - inductance and resistance meter The following are used for stimulus of the circuit under test: Power supplies Signal generator Digital pattern generator Pulse generator The following analyze the response of the circuit under test: Oscilloscope Frequency counter And connecting it all together: Test probes Meters Solenoid voltmeter Clamp meter Wheatstone bridge Capacitance meter LCR meter EMF Meter Electrometer RF probe Signal tracer Logic analyzer Spectrum analyzer Protocol analyzer Vector signal analyzer Time-domain reflectometer Semiconductor curve tracer Signal generator distinguished by frequency range or waveform type Frequency synthesiser Function generator Digital pattern generator Pulse generator Signal injector Boxcar averager Continuity tester Cable tester Hipot tester Network analyzer Test light Transistor tester Tube tester Several modular electronic instrumentation platforms are in common use for configuring automated electronic test and measurement systems.
These systems are employed for incoming inspection, quality assurance, production testing of electronic devices and subassemblies. Industry-standard communication interfaces link signal sources with measurement instruments in “rack-and-stack” or chassis-/mainframe-based systems under the control of a custom software application running on an external PC; the General Purpose Interface Bus is an IEEE-488 standard parallel interface used for attaching sensors and programmable instruments to a computer. GPIB is a digital 8-bit parallel communications interface capable of achieving data transfers of more than 8 Mbytes/s, it allows daisy-chaining up to 14 instruments to a system controller using a 24-pin connector. It is one of the most common I/O interfaces present in instruments and is designed for instrument control applications; the IEEE-488 specifications standardized this bus and defined its electrical and functional specifications, while defining its basic software communication rules. GPIB works best for applications in industrial settings that require a rugged connection for instrument control.
The original GPIB standard was developed in the late 1960s by Hewlett-Packard to connect and control the programmable instruments the company manufactured. The introduction of digital controllers and programmable test equipment created a need for a standard, high-speed interface for communication between instruments and controllers from various vendors. In 1975, the IEEE published ANSI/IEEE Standard 488-1975, IEEE Standard Digital Interface for Programmable Instrumentation, which contained the electrical and functional specifications of an interfacing system; this standard was subsequently revised in 1978 and 1990. The IEEE 488.2 specification includes the Standard Commands for Programmable Instrumentation, which define specific commands that each instrument class must obey. SCPI ensures configurability among these instruments; the IEEE-488 bus has long been popular because it is simple to use and takes advantage of a large selection of programmable instruments and stimuli. Large systems, have the following limitations: Driver fanout capacity limits the system to 14 devices plus a controller.
Cable length limits the controller-device distance to two meters per device or 20 meters total, whichever is less. This imposes transmission problems on systems spread out in a room or on systems that require remote measurements. Primary addresses limit the system to 30 devices with primary addresses. Modern instruments use secondary addresses so this puts a 30-device limit on system size; the LXI Standard defines the communication protocols for instrumentation and data acquisition systems using Ethernet. These systems are base
United States Armed Forces
The United States Armed Forces are the military forces of the United States of America. It consists of the Army, Marine Corps, Air Force, Coast Guard; the President of the United States is the Commander-in-Chief of the Armed Forces and forms military policy with the Department of Defense and Department of Homeland Security, both federal executive departments, acting as the principal organs by which military policy is carried out. All five armed services are among the seven uniformed services of the United States. From the time of its inception, the U. S. Armed Forces played a decisive role in the history of the United States. A sense of national unity and identity was forged as a result of victory in the First Barbary War and the Second Barbary War. So, the founders of the United States were suspicious of a permanent military force, it played a critical role in the American Civil War, continuing to serve as the armed forces of the United States, although a number of its officers resigned to join the military of the Confederate States.
The National Security Act of 1947, adopted following World War II and during the Cold War's onset, created the modern U. S. military framework. The Act established the National Military Establishment, headed by the Secretary of Defense, it was amended in 1949, renaming the National Military Establishment the Department of Defense, merged the cabinet-level Department of the Army, Department of the Navy, Department of the Air Force, into the Department of Defense. The U. S. Armed Forces are one of the largest militaries in terms of the number of personnel, it draws its personnel from a large pool of paid volunteers. Although conscription has been used in the past in various times of both war and peace, it has not been used since 1973, but the Selective Service System retains the power to conscript males, requires that all male citizens and residents residing in the U. S. between the ages of 18–25 register with the service. On February 22, 2019, however, a federal judge ruled that registering only males for Selective Service is unconstitutional.
As of 2017, the U. S. spends about US$610 billion annually to fund its military forces and Overseas Contingency Operations. Put together, the U. S. constitutes 40 percent of the world's military expenditures. The U. S. Armed Forces has significant capabilities in both defense and power projection due to its large budget, resulting in advanced and powerful technologies which enables a widespread deployment of the force around the world, including around 800 military bases outside the United States; the U. S. Air Force is the world's largest air force, the U. S. Navy is the world's largest navy by tonnage, the U. S. Navy and the U. S. Marine Corps combined are the world's second largest air arm. In terms of size, the U. S. Coast Guard is the world's 12th largest naval force; the history of the U. S. Armed Forces dates to 14 June 1775, with the creation of the Continental Army before the Declaration of Independence marked the establishment of the United States; the Continental Navy, established on 13 October 1775, Continental Marines, established on 10 November 1775, were created in close succession by the Second Continental Congress in order to defend the new nation against the British Empire in the American Revolutionary War.
These forces demobilized in 1784. The Congress of the Confederation created the current United States Army on 3 June 1784; the United States Congress created the current United States Navy on 27 March 1794 and the current United States Marine Corps on 11 July 1798. All three services trace their origins to their respective Continental predecessors; the 1787 adoption of the Constitution gave the Congress the power to "raise and support armies", to "provide and maintain a navy" and to "make rules for the government and regulation of the land and naval forces", as well as the power to declare war. The President is the U. S. Armed Forces' commander-in-chief; the United States Coast Guard traces its origin to the founding of the Revenue Cutter Service on 4 August 1790 which merged with the United States Life-Saving Service on 28 January 1915 to establish the Coast Guard. The United States Air Force was established as an independent service on 18 September 1947. S. Signal Corps, formed 1 August 1907 and was part of the Army Air Forces before becoming an independent service as per the National Security Act of 1947.
The United States Public Health Service Commissioned Corps was considered to be a branch of the United States Armed Forces from 29 July 1945 until its status as such was revoked on 3 July 1952. On March 1st, 2019, the Department of Defense sent a proposal to Congress that would establish the United States Space Force as an independent military service within the Department of the Air Force. If approved, this would become the sixth military service branch to be created. Command over the U. S. Armed Forces is established in the Constitution; the sole power of command is vested in the President by Article II as Commander-in-Chief. The Constitution presumes the existence of "executive Departments" headed by "principal officers", whose appointment mechanism is provided for in the Appointments Clause; this allowance in the Constitution formed the basis for creation of the Department of Defense in 1947 by the National Security Act. The DoD is headed by the Secretary of Defense, a civilian and member of the Cabinet.
The Defense Secretary is second in the U. S. Armed Forces chain of command, with the exception of the Coast Guard, under the Secretary of Homeland Security, is just below the President and serves as the