Since the river site was amidst his estate, Philip opposed the idea and strongly favored a site at the head of Hunting Creek (also known as Great Hunting Creek). It has been said that in order to avoid a predicament the petitioners offered to name the new town Alexandria, in honor of Philip's family. As a result, Philip and his cousin Captain John Alexander (1711–1763) gave land to assist in the development of Alexandria and are thus listed as the founders. This John was the son of Robert Alexander II (1688–1735). On May 2, 1749, the House of Burgesses approved the river location and ordered "Mr. Washington do go up with a Message to the Council and acquaint them that this House have agreed to the Amendments titled An Act for erecting a Town at Hunting Creek Warehouse, in the County of Fairfax."[13] A "Public Vendue" (auction) was advertised for July, and the county surveyor laid out street lanes and town lots. The auction was conducted on July 13–14, 1749.

Often referred to its DuPont trade name Teflon, PTFE is a polymer with very unique properties. Due to its chemical composition and physiologically neutral properties, it is a plastic material with a very broad range of chemical resistance and very low coefficient of friction; however it has some restrictions in terms of mechanical properties and wear characteristics. Therefore PTFE is often modified by adding various fillers to improve specific properties such as wear or extrusion resistance. One important characteristic of PTFE is the low friction coefficient giving outstanding stick-slip performance. Therefore PTFE is the preferred material in applications requiring accurate positioning of hydraulic cylinders. Due to increased modulus of elasticity compared to rubbers and polyurethanes, PTFE seals cannot usually be installed by simple snap-in measures therefore require special tools and procedures for installation.

Viscosity is a measurement of the thickness of the fluid or resistance to flow. Seal performance is affected by the viscosity of the fluid and changes to viscosity during use. Most typical hydraulic fluids exhibit decreased viscosity with increasing temperature and increased viscosity with increasing pressure.

According to archaeologists' estimates, a succession of indigenous peoples began to occupy the Chesapeake and Tidewater region about 3,000 to 10,000 years ago. Various Algonquian-speaking peoples inhabited the lands in the Potomac River drainage area since at least the early 14th century.[6]

Oilseals online

City councils elected under the new ward system began to take a more direct role in city administration. The city council and city manager gave conflicting orders to city employees while spending increased to accommodate appropriations coming from both the council and manager. With over one million dollars spent on unauthorized projects, a movement to go back to at-large councilmen emerged. In 1944, a referendum to eliminate the ward system ended with a vote in favor of the ward system. Shortly afterwards, a number of high-ranking city officials resigned, and residents appealed to the Circuit Court for an order to force a referendum. Unbeknownst to the city government, Delegate Armistead Boothe introduced a bill in Richmond to hold another referendum. This bill passed the General Assembly and a vote was held on March 2, 1948. The options in the referendum included retaining the extant system or replacing it with a council of seven at-large members. Voters approved the new system with 61% of votes in favor.[120] More recently, a 1983 push by the Virginia NAACP to return to the ward system failed because of a lack of support from elected officials.[121]

In March 1785, commissioners from Virginia and Maryland met in Alexandria to discuss the commercial relations of the two states, finishing their business at Mount Vernon. The Mount Vernon Conference concluded on March 28 with an agreement for freedom of trade and freedom of navigation of the Potomac River. The Maryland legislature, in ratifying this agreement on November 22, proposed a conference among representatives from all the states to consider the adoption of definite commercial regulations. This led to the calling of the Annapolis Convention of 1786, which in turn led to the calling of the Federal Convention of 1787.[15]

In March 1959, Lieutenant Colonel William Henry Whalen, the "highest-ranking American ever recruited as a mole by the Russian Intelligence Service", provided Colonel Sergei A. Edemski three classified Army manuals in exchange for $3,500 at a shopping center parking lot within the city.[39] Agents of the Federal Bureau of Investigation later arrested Whalen on July 12, 1966, at his home in the city.[40]: p1  In 1961 the original Woodrow Wilson Bridge opened.[41]

Concurrent highways I-95 and I-495 (the Capital Beltway), including the Woodrow Wilson Bridge over the Potomac River, roughly parallels the city's southern boundary with Fairfax County before very briefly passing through D.C. and entering Maryland. Interstate 395 crosses north and south through the western part of the city. Alexandria is bisected east and west by State Route 7 (VA 7/King Street). The most western section of King Street in the city was once the terminus of the Leesburg Turnpike. VA 7 terminates at State Route 400 (VA 400/Washington Street), which connects the northern and southern segments of George Washington Memorial Parkway (G.W. Parkway). State Route 236 (VA 236/Duke Street) runs east–west along the southern side of the city, also terminating at VA 400 in Old Town. Other primary state highways serving Alexandria include the short limited-access State Route 241 (Telegraph Road), as well as multiple thoroughfares serving the western side of the city, which are State Route 401 (Van Dorn Street), State Route 402 (Quaker Lane), and State Route 420 (Seminary Road in the west, Janneys Lane in the east). U.S. Route 1 (Richmond Highway) passes north–south through the city, parallel and west of Washington Street and the G.W. Parkway. Through Old Town, the highway follows Patrick and Henry Streets.[136][137]

In November 2020, the school board unanimously voted to rename T. C. Williams High School and Matthew Maury Elementary School. The high school was renamed Alexandria City High School and Maury Elementary was renamed Naomi L. Brooks Elementary School, effective July 1, 2021.[48][49]

The historic center of Alexandria is known as Old Town Alexandria, or simply "Old Town". With its concentration of boutiques, restaurants, antique shops and theaters, it is a major draw for city residents and visitors. Like Old Town, many Alexandria neighborhoods are compact and walkable. A large portion of adjacent Fairfax County, mostly south but also west of the city, has Alexandria mailing addresses. However, this area is under the jurisdiction of Fairfax County's government and separate from the independent city.[5] The city is therefore sometimes referred to as the "City of Alexandria" to avoid confusion.

NSK bearing numbers are alphanumeric combinations that indicate the NSK bearing type, boundary dimensions, dimensional and running accuracies, internal ...

In 1965, the city integrated schools.[42]: 69  In 1971, the city consolidated all high school junior and senior students into T. C. Williams High School. Freshman and sophomore students were assigned to attend either Francis C Hammond or George Washington, formerly four-year high schools, as part of a system-wide overhaul of the public school system, beginning with kindergarten classes, in an attempt to racially "balance" student population throughout the city's public schools to better reflect the city's racial makeup. The plan was known as the "K-6, 2, 2, 2 plan". Classes were broken out, beginning with kindergarten through sixth grade; then seventh through eighth; then freshman and sophomore classes; and finally junior and senior classes, with the changes including being moved to a different school building.[42]: 69  The same year that head coach Herman Boone joined the school and lead the football team to a 13–0 season, a state championship, and a national championship runner-up; the basis for the 2000 film Remember the Titans where Boone was portrayed by Denzel Washington.[43]

The Alexandria city government operates its own mass transit system, the DASH bus, connecting points of interest with local transit hubs. Since 2021, DASH is fare-free.[138] DASH also offers a "trolley" diesel bus service on King Street from the King Street–Old Town Metro station to the Waterfront.[139] Metrobus also serves Alexandria along with Metrorail's Blue and Yellow Lines with stops at Potomac Yard, Braddock Road, King Street-Old Town, Eisenhower Avenue, and Van Dorn Street. Hornblower Cruises operates the Potomac Water Taxi to and from Georgetown and The Wharf development in D.C. and the National Harbor development in Prince George's County.[140]

Virginia Tech's Washington-Alexandria Architecture Center, also known as WAAC, is located on Prince Street in Old Town, offering graduate programs in Urban Affairs and Planning, Public and International Affairs, Architecture, and Landscape Architecture. In 2018, Virginia Tech announced the construction of an "Innovation Campus" in Potomac Yard with graduate programs in computer science and computer engineering.[131] Virginia Commonwealth University operates a Northern Virginia branch of its School of Social Work and The George Washington University also has a campus near the King Street–Old Town station. This campus mainly offers professional and vocational programs, such as an executive MBA program, urban planning and security studies. The city also has a campus of the Northern Virginia Community College. The largest seminary in the Episcopal Church, Virginia Theological Seminary, is located on Seminary Road.

In 1955, then-Representative and future President Gerald R. Ford and his family moved to Alexandria from Georgetown.[37]: 95  The Fords remained in their Alexandria home during Ford's tenure as Vice President (1973–1974), as the vice president did not yet have an official residence.[38] Following the resignation of Richard Nixon, Ford spent his first 10 days as President in the house before moving to the White House.[38]

In addition to these considerations, the structure and morphology (the study of form and shape) of polymeric materials make selection and specification of seal materials much more complicated than the standard materials used in mechanical engineering (such as aluminium and steel). Mechanical properties of polymeric materials are strongly influenced by time, temperature, load and rate of motion. Highly complex intermolecular processes affect the stress relaxation and retardation phenomena. Furthermore, the tribology of the system (e.g. friction and wear) has a strong influence on the seal material properties and vice versa.

At the 2010 census,[84] there were 139,966 people, 68,082 households and 30,978 families residing in the city. The population density was 8,452.0 inhabitants per square mile (3,263.3/km2). There were 68,082 housing units at an average density of 4,233.2 per square mile (1,634.4/km2). The racial/ethnic mix of the population was:

Many areas outside the city have an Alexandria mailing address yet are a part of Fairfax County including: Hollin Hills, Franconia, Groveton, Hybla Valley, Huntington, Lincolnia, Belle Haven, Mount Vernon, Fort Hunt, Engleside, Burgundy Village, Waynewood, Wilton Woods, Rose Hill, Virginia Hills, Hayfield, and Kingstowne. Some refer to these areas as Lower Alexandria, South Alexandria, or Alexandria, Fairfax County.[74]

In 2024, the city has 55 boards and commissions to advise the City Council on major issues affecting the community.[112] The majority of members are appointed by the City Council.[113] In addition, Alexandria City Public Schools has a school board with nine members. Three are elected from each of the city's three school board districts.[114]

Rigid Thermoplastics, thermosets and their composites are characterised by much higher hardness and stiffness as well as reduced elasticity compared to polyurethanes, rubbers and PTFE. Therefore they’re used for components where mechanical strength is more important than flexibility, such as guide rings, anti-extrusion rings and special seal arrangements for heavy duty applications. Rigid thermoplastics and composites.

Alexandria remained under military occupation until the end of the Civil War. Fort Ward, one of a ring of forts built by the Union army for the defense of Washington, D.C., is located inside the boundaries of present-day Alexandria.[25] There were five military prisons in the city, the largest being the Washington Street Military Prison.[26][27] After the creation by Washington of the state of West Virginia in 1863 and until the close of the war, Alexandria was the seat of the so-called Restored Government of Virginia, also known as the "Alexandria Government".[15] During the Union occupation, a recurring contention between the Alexandria citizenry and the military occupiers was the Union army's periodic insistence that church services include prayers for the President of the United States. Failure to do so resulted in incidents including the arrest of ministers in their church.

In 1755, General Edward Braddock organized his fatal expedition against Fort Duquesne at Carlyle House in Alexandria. In April 1755, the governors of Virginia, and the provinces of Maryland, Pennsylvania, Massachusetts, and New York met to determine upon concerted action against the French in America.[15]

Your Premier Source for 2010 Nissan Maxima Raybestos 713296 Wheel Bearing and Hub Assembly-PG Plus FrontRear - Checkout our Live Inventory & Save Today With ...

The most commonly used media in hydraulic systems are mineral oil based fluids with various additives. However, a variety of alternative fluids may be encountered in special applications. For example, biodegradable fluids such as synthetic (HEES) or natural esters (HETG) and polyalphaolefines (POA) may be used to reduce environmental impact in the event of accidental spills. Flame retardant fluids based on water or synthetic esters may be safely used in confined spaces or where hydraulic systems are used in close proximity to ignition sources.

13% of people that work in Alexandria live in the city, while 87% commute in, with 37% of those commuters being from Fairfax County. An additional 61,000 people commute out of Alexandria to work. 35% commute to Washington, D.C., and 29% commute to Fairfax County.[90] As of March 2024, 2.0% of Alexandria residents are unemployed.[91]

Capital Bikeshare, a bicycle-sharing public transportation system, launched in Alexandria in 2012.[143] The system has 62 rental locations throughout the city.[144] The East Coast Greenway and Mount Vernon Trail cycle routes pass through Alexandria.

On October 21, 1669, a patent granted 6,000 acres (24 km2) to Robert Howsing for transporting 120 people to the Colony of Virginia.[9]: 5  That tract later became the City of Alexandria.[9]: 5  Virginia's comprehensive Tobacco Inspection Law of 1730 mandated that all tobacco grown in the colony must be brought to locally designated public warehouses for inspection before sale. One of the sites designated for a warehouse on the upper Potomac River was at the mouth of Hunting Creek.[10] However, the ground proved to be unsuitable, and the warehouse was built half a mile up-river, where the water was deep near the shore.

Major employment sectors in Alexandria include management consulting, business and finance, office and administrative support, computer and mathematical, sales, and legal. Jobs in Alexandria are highly concentrated around the city's Metrorail stations, primarily in Old Town North and the Braddock Road area, Old Town, and Carlyle near the Eisenhower Avenue station, as well as along the I-395 corridor on the west side of the city.

In the waning years of the 19th century, Alexandria suffered its two documented lynchings. The first, in 1897, was Joseph H. McCoy and the second, in 1899, was Benjamin Thomas. Both were Black male teenagers accused, but never convicted, of assaulting young white girls that were known to them. They were both kidnapped from jail and hanged by mobs.[30]

The ZIP Code prefix 223 uniquely identifies the Alexandria postal area.[citation needed] However, the Alexandria postal area extends into Fairfax County and includes addresses outside of the city. Delivery areas have ZIP Codes 22301, 22302, 22303, 22304, 22305, 22306, 22307, 22308, 22309, 22310, 22311, 22312, 22314, and 22315, with other ZIP Codes in use for post office boxes and large mailers (22313, 22331, 22332, 22333).

Following the 1745 settlement of the Colony of Virginia's 10-year dispute with Thomas Fairfax, 6th Lord Fairfax of Cameron over the western boundary of the Northern Neck Proprietary, when the Privy Council in London found in favor of Lord Fairfax's expanded claim, some of the Fairfax County gentry formed the Ohio Company of Virginia. They intended to conduct trade into the interior of America, and they required a trading center near the head of navigation on the Potomac. The best location was Hunting Creek tobacco warehouse, since the deep water could easily accommodate sailing ships. Many local tobacco planters, however, wanted a new town further up Hunting Creek, away from nonproductive fields along the river.[11]

The first fatalities of the North and South in the American Civil War occurred in Alexandria. Within a month of the Battle of Fort Sumter, the Civil War's first battle, Union Army troops occupied Alexandria, landing troops at the base of King Street on the Potomac River on May 24, 1861. A few blocks up King Street from their landing site, the commander of the New York Fire Zouaves, Colonel Elmer E. Ellsworth, sortied with a small detachment to remove a large Confederate flag displayed on the roof of the Marshall House Inn that had been visible from the White House. While descending from the roof, Ellsworth was shot dead by James W. Jackson, the hotel's proprietor. One of Ellsworth's soldiers immediately killed Jackson.[22][23] Ellsworth was publicized as a Union martyr, and the incident generated great excitement in the North, with many children being named for him.[22][23] Jackson's death defending his home caused a similar sensation in the South.[22][24]

In 2000, there were 61,889 households, of which 18.6% had children under the age of 18 living with them, 32.2% were married couples living together, 9.2% had a female householder with no husband present, and 55.2% were non-families. 43.4% of all households were made up of individuals, and 6.8% had someone living alone who was 65 years of age or older. The average household size was 2.04 and the average family size was 2.87.

The city is home to Cameron Run Regional Park, operated by NOVA Parks, which includes a water park, a miniature golf course, and batting cages. NOVA Parks also operates the Winkler Botanical Preserve in the city's West End.[109] A portion of the Mount Vernon Trail, a popular bike and jogging path, runs through Old Town near the Potomac River on its way from the Mount Vernon Estate to Roosevelt Island in Washington, D.C. There is also a largely unbroken line of parks stretching along the Alexandria waterfront.

A popular Christmas time attraction in Alexandria is the Scottish Christmas Walk, which was established in 1969.[93] The event, which involves a parade through the center of Old Town Alexandria, celebrates the city's Scottish heritage, and is the centerpiece of a yearly holiday festival.[94] It serves as a fundraiser for social services in Alexandria.[93] Other parades in Old Town celebrate Saint Patrick's Day[95] and the birthday of George Washington.[96] Other annual events include the Red Cross Waterfront Festival in June, the city's birthday celebration with fireworks show in July, various ethnic heritage days at Tavern Square, and "First Night Alexandria" on New Year's Eve.

Predictive or condition-based maintenance is a proactive maintenance strategy that allows you to monitor the performance and condition of your machinery in ...

Alexandria has two local weekly newspapers: the Alexandria Gazette Packet and the Alexandria Times.[103] The Alexandria Gazette was once published in the city from 1834 to 1974.[104]

Materials play a major role in the performance and lifetime of seals. Generally, hydraulic seals are exposed to a variety of application and working conditions such as a wide temperature range, contact with various hydraulic fluids and the outside environment as well as high pressure and contact forces. The appropriate seal materials have to be selected to achieve a reasonable service life and service intervals. A wide variety of seal materials from four major polymeric material groups is available:

Cassette Seal / Case seal. High-speed PTFE lip seals are designed for rotary applications where elastomer lip seals fail, and mechanical seals are too costly.

In 1930, Alexandria annexed the town of Potomac from Arlington County. Alexandria and Potomac stood in stark contrast. The streetcar suburb commuter town of Potomac had, as part of Arlington, been heavily influenced by the anti-vice crusades of staunch progressive Commonwealth's Attorney Crandal Mackey. In Potomac, slaughterhouses and saloons were banned. Residents of the former town of Potomac had a different identity from those in Alexandria, and after annexation former Potomac residents began to push for the reimplementation of the ward system. In a 1932 referendum, voters decided in favor of a new plan that would expand the city council to nine members; three elected at-large and six elected by ward. Support for the new plan was highest in the former town of Potomac.[120]

A hydraulic cylinder is a linear actuator used to push or pull a load, or to selectively resist motion under load by means of fluid pressure. Double-acting cylinders, the most common type, are able to push and pull (see Fig.1). High pressure fluid is pumped into the extend chamber port (Fig.1: A) and acts on the piston to push the piston rod out, thereby extending the length of the cylinder. Inversely, to retract the piston rod and reduce the length of the assembly, high pressure fluid is pumped into the retract chamber port (Fig.1: B) and acts on the opposite side of the piston.

The Torpedo Factory Art Center, located on the Old Town waterfront, is a former torpedo factory that now serves as an art center filled with independent art studios and exhibits. The Athenaeum is another center for the arts. Also located in Old Town is Little Theatre of Alexandria, a community theatre at 600 Wolfe Street. South of Old Town on the Potomac River is the Jones Point Light and the nearby south cornerstone of the original District of Columbia. Immediately west of Old Town is the United States Patent and Trademark Office which includes the National Inventors Hall of Fame Museum.[100] The Birchmere is a concert hall that features musical acts as well as ethnic and comedic performers. Site of interests with Alexandria addresses but located outside of the city include River Farm, Collingwood Library & Museum, Green Spring Gardens Park, Huntley Meadows Park, Historic Huntley, Pope-Leighey House (designed by Frank Lloyd Wright), Woodlawn Plantation, and George Washington's Grist Mill and Mount Vernon Estate.

The chemical composition on hydraulic fluids can impact the seal life and system performance depending on fluid compatibility with the seal material. Absorption and reaction of seal materials with non-compatible fluids can cause for example:

In 2008 the City Council approved a charter where "citizens, businesses, and city government participate in a vibrant community that is always mindful of the needs and lifestyles of the generations to come".[122]: 4  That charter defined sustainability as "meeting our community's present needs while preserving our historic character and ensuring the ability of future generations to meet their own needs".[122]: 5  An ecocity is defined as "an ecologically healthy city".[123]: 3  In 2022, Alexandria enacted a 5-cent plastic bag tax consistent with the phase-out of lightweight plastic bags in the United States.[124]

These parades and other official events are typically led by Alexandria's town crier, who, often dressed in elaborately, by a tradition dating to the 18th century, in a red coat, breeches, black boots and a tricorne hat, welcomes participants.[97][98]

The fluids used in hydraulic systems come in various chemical compositions and viscosity grades as suited to specific applications.

The type of cylinder and the application in which it’s used are two of the main criteria to determine which seals and guides are selected. Applications are referred to as light duty, medium duty and heavy duty. These classifications are somewhat subjective but the duty levels are typically characterised by the following criteria.

Every four years, Alexandria residents elect a sheriff that leads the Sheriff's Office in overseeing roughly 200 deputies and a detention center for pre-trial and short-term inmates.[128] This jail is used to house pre-trial inmates in federal espionage cases.[129]

Alexandria's primary law enforcement is the Alexandria Police Department (APD) which is led by a Chief of Police who is appointed by city government.[125] In April 2022, Don Hayes was appointed as Chief of Police.[126] As of 2023, the APD employs roughly 300 officers that receive training at the Northern Virginia Criminal Justice Training Academy.[127]

Alexandria is home to many charities and non-profit organizations including the national headquarters of Catholic Charities, Citizens for the Republic, Global Impact, Good360, International Centre for Missing & Exploited Children, Islamic Relief USA, United Way, and Volunteers of America. Trade associations located in the city include the American Counseling Association, the Human Resource Certification Institute, the Society for Human Resource Management, the National Society of Professional Engineers, the National Beer Wholesalers Association, the American Society of Clinical Oncology, National Industries for the Blind, American Physical Therapy Association, the National Association of Convenience Stores, and the American International Automobile Dealers Association. Alexandria also has a Chamber of Commerce and other business associations including the West End Business Association, the Del Ray Business Association and the Old Town Business Association.

SHOP 6003 Ball Bearing from MISUMI today w/ our bearings selector. Brands Carried: MISUMI, NSK, NTN, Nachi-Fujikoshi, EZO. Seals: Z, ZZ, 2RS.

The Mayor, who is chosen on a separate ballot, presides over meetings of the Council and serves as the ceremonial head of government. The Mayor does not have the power to veto Council action. Council members traditionally choose the person receiving the most votes in the election to serve as Vice Mayor. In the absence or disability of the Mayor, the Vice Mayor performs the mayoral duties.

The city is home to the Alexandria Aces of the Cal Ripken Sr. Collegiate Baseball League. The team's home field is Frank Mann Field.[105] Alexandria had previously been home of one professional sports team, the Alexandria Dukes, a minor league baseball team which moved to Woodbridge in 1984 to become The Prince William Pirates (now known as the Fredericksburg Nationals).[106]

In 1972, Clifford T. Cline purchased the 1890 Victorian house at 219 King Street and converted it into the Creole serving Two-Nineteen Restaurant.[44]: 167  In 1973, Nora Lamborne and Beverly Beidler became the first women elected to the city council.[32]: 63  In 1974, the Torpedo Factory Art Center opened.[36] In 1983, the King Street–Old Town station, Braddock Road station, and Eisenhower Avenue station opened as the Washington Metro system expanded.[41] In 1991, the Van Dorn Street station opened and Patricia Ticer became the first woman to be elected mayor.[32]: 63

As of 2024, the City of Alexandria is divided into 19 "Small Area Plans" and 11 additional overlapping plans.[54] These areas and their component neighborhoods include:

Almost immediately upon establishment, the town founders called the new town "Belhaven", believed to be in honor of a Scottish patriot, John Hamilton, 2nd Lord Belhaven and Stenton, the Northern Neck tobacco trade being then dominated by Scots. The name Belhaven was used in official lotteries to raise money for a Church and Market House, but it was never approved by the legislature and fell out of favor in the mid-1750s.[14] The town of Alexandria did not become incorporated until 1779.

In 1830, John Hollensbury's home in Alexandria was one of two homes directly bordering an alleyway that received a large amount of horse-drawn wagon traffic and loiterers.[101] In order to prevent people from using the alleyway, Hollensbury constructed a 7 feet (2.1 m) wide, 25 feet (7.6 m) deep, 325-square-foot (30.2 m2), two-story home using the existing brick walls of the adjacent homes for the sides of the new home.[101] The brick walls of the Hollensbury Spite House living room have gouges from wagon-wheel hubs; the house is still standing, and is occupied.[101]

To support sealing function and keep the contact force for long seal life, many different properties should be considered to provide effective seal performance, examples include:

After all slaves in the seceding states were liberated, even more African Americans came to Alexandria. By the fall of 1863, the population of Alexandria had exploded to 18,000—an increase of 10,000 people in 16 months.[28]

Alexandria is served by Inova Alexandria Hospital. The city's health department operates a health clinic at Mark Center in the city's West End and a teen wellness center at Alexandria City High School.[135]

Since its foundation, Alexandria's government has had several different forms of government. Before 1921, Alexandria had an elected eight-member Board of Aldermen and a sixteen-member Common Council whose members were elected by ward. In addition, there was an elected mayor with the power to veto legislation from the two councils. Reformers within the city during the early 20th century hoped to adopt the then-popular council-manager system. As a means to implementing this new system, the reformists proposed a plan to create a single city council elected at-large. This new system was adopted in 1921 and the first at-large councilmen were elected in June 1922.[119]

Rubbers are widely used in the sealing industry for rotary shaft seals, static sealing elements such as o’rings and energisers as well as dynamic seals in the fluid power industry. Depending on the chemical composition, rubbers can cover a wide temperature range up to 200°C (390°F) and more and can withstand a wide variety of hydraulic fluids. NBR elastomer in a hardness range of 70 to 90 Shore A Durometer are the most commonly used rubbers in the fluid industry. For higher temperatures and more aggressive hydraulic fluids, HNBR and FKM material is often used.

According to the U.S. Census Bureau, the city has a total area of 15.5 square miles (40.1 km2), of which 15.0 square miles (38.9 km2) is land and 0.42 square miles (1.1 km2), or 2.85%, is water.[52] Alexandria is bounded on the east by the Potomac River (which forms the boundary between the city and Washington, D.C. and Prince George's County, Maryland), on the north and northwest by Arlington County, and on the south by Fairfax County. The western portions of the city were annexed from those two entities beginning in the 1930s.[53]

Alexandria is home to private schools such as St. Stephen's and St. Agnes School, Bishop Ireton High School, and Episcopal High School. Also in the city are Alexandria Country Day School, Commonwealth Academy, the Basilica School of Saint Mary, St. Rita's Catholic School, Blessed Sacrament School, and Global Health College.

In 1814, during the War of 1812, the British military carried out a successful raid on Alexandria, which surrendered without a fight. In order to avoid the town's destruction, twenty-two merchant ships and large quantities of flour, tobacco, cotton, wine, and sugar were handed over by Alexandria's municipal authorities to the British.[16] In 1823 William Holland Wilmer, Francis Scott Key, and others founded the Virginia Theological Seminary.[17]: 116  From 1828 to 1836,[18] Alexandria was home to the Franklin & Armfield Slave Market, one of the largest slave trading companies in the country. By the 1830s, they were sending more than 1,000 slaves annually from Alexandria to their Natchez, Mississippi, New Orleans, and later Texas markets to help meet the demand for slaves in Mississippi and nearby states.[19] Later owned by Price, Birch & Co., the slave pen became a jail under Union occupation.[20]

Landmarks within the city include the George Washington Masonic National Memorial (also known as the Masonic Temple) and Observation Deck, Christ Church, Gadsby's Tavern, Stabler-Leadbeater Apothecary Shop, John Carlyle House, Lee-Fendall House, Robert E. Lee's boyhood home, and the Alexandria City Hall with the adjacent Market Square. Other sites of historical interest in the city include Fort Ward Park and Museum, Phoenix Mill, and the Alexandria Canal lock re-creation at Canal Office Center. The Alexandria Black History Museum, Alexandria Archaeology Museum, and the Lyceum display various aspects of the city's history.[99]

Hydraulicrod seals

As an independent city of Virginia (as opposed to an incorporated town within a county), Alexandria derives its governing authority from the Virginia General Assembly using the Dillon Rule. In order to revise the power and structure of the city government, the city must request the General Assembly to amend the charter. The present charter was granted in 1950 and it has been amended in 1968, 1971, 1976, and 1982.

As of ratification of the Fifteenth Amendment, Alexandria County's black population was more than 8,700, or about half the total number of residents in the county. This newly enfranchised constituency provided the support necessary to elect the first black Alexandrians to the City Council and the Virginia Legislature.[29]

Heavy duty cylinders are typically used in off-highway earthmoving, mining and forestry equipment and may be characterised by:

Alexandria has over 900 acres (3.6 km2) of protected open space with 566 acres of city-owned park land and 10 recreation centers,[107] of which Chinquapin is one of the largest. Chinquapin offers facilities for swimming, tennis, racquetball, and other sports.[108] The city also organizes several sports leagues throughout the year including volleyball, softball and basketball.

Until 2014, local legislation mandated that all new north–south streets in the city be named for Confederate military leaders.[45] Efforts have increased in recent years to expedite the renaming of these streets with Mayor Justin Wilson and the City Council setting a goal of renaming three of these streets annually.[46] In 2019, the name of U.S. 1 was changed from Jefferson Davis Highway to Richmond Highway.[47]

Alexandria Union Station, the city's historic train station, has Amtrak intercity services and the Virginia Railway Express (VRE) regional rail service. The station is directly adjacent to the King Street–Old Town Metro station. The traditional boundary between Old Town and the latterly annexed sections of the city follows the railway acquired by Virginia in 2021 and formerly owned by CSX Transportation.[141] In addition, Norfolk Southern Railway operates a freight rail line and a transload terminal in the city.[142]

President Woodrow Wilson visited the Virginia Shipbuilding Corporation on May 30, 1918, to drive the first rivet into the keel of the SS Gunston Hall.[32]: 50  In 1930, Alexandria annexed the town adjacent to Potomac Yard incorporated in 1908 named Potomac. In 1938 the Mt. Vernon Drive-In cinema opened.[33] In 1939, the segregated public library experienced a sit-in organized by Samuel Wilbert Tucker.[34] In 1940, both the Robert Robinson Library, which is now the Alexandria Black History Museum, and the Vernon Theatre opened[35] Jim Morrison of The Doors, as well as Cass Elliot and John Phillips of The Mamas & The Papas attended the George Washington High School in the 1950s.[36]

Alexandria is an independent city in the northern region of the Commonwealth of Virginia, United States. It lies on the western bank of the Potomac River approximately 7 miles (11 km) south of downtown Washington, D.C. Alexandria is the third-largest principal city of the Washington metropolitan area, which is part of the larger Washington–Baltimore combined statistical area. As of 2022, the city's population of 159,467 made it the sixth-most populous city in Virginia and the 173rd-most populous city in the nation.[4]

The city is served by the Alexandria City Public Schools system. Alexandria's public school system consists of twelve elementary schools for grades Kindergarten through 5th grade, with three of them also offering Pre-K. Two schools, Patrick Henry and Jefferson-Houston, are Pre-K through 8th grade schools while the middle schools, George Washington and Francis C. Hammond, serve 6th through 8th graders. Minnie Howard Ninth Grade Center serves 9th graders while the Alexandria City High School serves 10th through 12th for the entire city.

According to 2022 American Community Survey 1-Year Estimates, 69.9% of Alexandria residents aged 25 and older have attained a bachelor's degree or higher, compared with 42.2% statewide.[87][88]

Companies headquartered in Alexandria include Crooked Beat Records, Five Guys, the Institute for Defense Analyses (IDA), The Motley Fool, Oblon law firm, Pentagon Federal Credit Union (PenFed), Port City Brewing Company, Purple Strategies, ThinkFun, and VSE. Several federal agencies are based in Alexandria, including the National Credit Union Administration, United States Patent and Trademark Office, National Science Foundation, Office of the Inspector General, U.S. Department of Defense, and the Food and Nutrition Service. The Department of Defense Education Activity (DoDEA), the federal school system for military dependents, is headquartered in Alexandria.[89]

Hydraulic seal

Alexandria has a circuit court and a general district court. The city also has a juvenile and domestic relations district court. All of these courts are located in the Alexandria Courthouse at 520 King Street.[115] The city is also the site of the Alexandria Division of the United States District Court for the Eastern District of Virginia.[116]

A portion of the City of Alexandria—most of the area now known as Old Town as well as the areas of the city northeast of what is now King Street—and all of today's Arlington County share the distinction of having been the portion of Virginia ceded to the U.S. Government in 1791 to help form the new District of Columbia. Over time, a movement grew to separate what was called "Alexandria County" from the District of Columbia. As competition grew with the port of Georgetown and the Chesapeake and Ohio Canal fostered development on the north side of the Potomac River, Alexandria's economy stagnated; at the same time, residents had lost any representation in Congress and the right to vote and were disappointed with the negligible economic benefit (on the Alexandria side) of being part of the national capital. Alexandria still had an important port and market in the slave trade, and as talk increased of abolishing slavery in the national capital, there was concern that Alexandria's economy would suffer greatly if this step were taken. After a referendum, voters petitioned Congress and Virginia to return the portion of the District of Columbia south of the Potomac River (Alexandria County) to Virginia. On July 9, 1846, Congress retroceded Alexandria County to Virginia.[21] The City of Alexandria was re-chartered in 1852 and became independent of Alexandria County in 1870. The remaining portion of Alexandria County changed its name to Arlington County in 1920.

Hydraulic fluid compatibility Thermoplastic ElastomersRubbersThermosets MaterialPolyurethanePolyurethaneHydrolysis Resistant PolyurethaneHydrolysis Resistant PolyurethaneEther-Based TPUEther-Based TPUPolyesterPolyesterNBR/HNBRNBR/HNBRFKMFKMEPDMPA/PFPMPEEKPTFE TemperatureNormalHighNormalHighNormalHighNormalHighNormalHighNormalHighAllAllAllAllAll Hydraulic FluidsUp to 60°CUp to 100°CUp to 60°CUp to 100°CUp to 60°CUp to 100°CUp to 60°CUp to 100°CUp to 60°CUp to 100°CUp to 60°CUp to 100°C Mineral Oils HL, HLP, HVLPABAAAB/CAA/BAAAADAAAA ATF: Automatic transmission fluidABAAAB/CABAAAADAAAA HETG (triglycerides, rape seed oil)AB/CAAACAB/CA/BA/BAADAAAA HEES (synthetic esters)AB/CAAACAB/CA/BA/BAADAAAA HEPG (polyalkylene glycols)BDACB/CDCDAA/BA/BC/DAAAAA HEPR (polyalphaolefins)ABAAAB/CABA/BA/BAADAAAA Fire Resistant Fluids, Water BasedUp to 40°CUp to 60°CUp to 40°CUp to 60°CUp to 40°CUp to 60°CUp to 40°CUp to 60°CUp to 40°CUp to 60°CUp to 40°CUp to 60°C WaterBDAAABABAAAAACAAA HFA Fluids (oil in water)BDAABB/CABAAABDCAAA HFB Fluids (water in oil)BDAABDABAAAADCAAA HFC Fluids (water – glycol)CDAB/CBB/CCDAAA/BB/CACAAA Fire Resistant Fluids, Water FreeUp to 60°CUp to 100°CUp to 60°CUp to 100°CUp to 60°CUp to 100°CUp to 60°CUp to 100°CUp to 60°CUp to 100°CUp to 60°CUp to 100°C HFD-R FluidsDDDDDDDDDDCCAAAAA HFD-U Fluids (polyol amd carboxylic esters)BDAABDAB/CCCAADAAAA Mineral GreasesABAAABAAAAAADAAAA

At the turn of the 20th century the most common production in the city was glass, fertilizer, beer, and leather. The glass often went into beer bottles. Much of the Virginia Glass Company effort went to supply the demands of the Robert Portner Brewing Company, until fire destroyed the St. Asaph Street plant on February 18, 1905. The Old Dominion Glass Company also had a glass works fall to fire, then built a new one. The Belle Pre Bottle Company held a monopoly on a milk bottle that they patented, yet that organization only lasted 10 years.[31] Most businesses were smaller where the business occupied the first floor of a building and the owner and family lived above.[32]: 50  Prohibition closed Portner Brewing in 1916.[32]: 50

The Oswald Durant Center in the Upper King Street neighborhood of the Old Town is named after Dr. Oswald Durant, one of the first African American doctors in Alexandria.[102]

In December 2023, Virginia Governor Glenn Youngkin and Monumental Sports & Entertainment founder Ted Leonsis announced plans to develop a 70-acre area in Potomac Yards to include a concert venue, businesses, and a new arena that would have been home to the Washington Capitals and Washington Wizards.[50] The proposal failed in March 2024 with the announcement Virginia negotiations were ending and Monumental planning to sign an additional lease with Washington, D.C. after it did not advance in the Virginia General Assembly.[51]

The climate in this area is characterized by hot, humid summers and generally mild to cool winters. According to the Köppen climate classification system, Alexandria has a humid subtropical climate, abbreviated "Cfa" on climate maps.[75]

According to 2019 Census Bureau data, the median household income was $103,284 and median family income was $130,395.[85] Additionally, 8.6% of the population of the population were below the poverty line.[86] 14.2% of those under the age of 18 and 3.1% of those 65 and older were living below the poverty line.

HydraulicramSealkit

Around 1746, Captain Philip Alexander II (1704–1753) moved to what is south of present Duke Street in Alexandria. His estate, which consisted of 500 acres (2.0 km2), was bounded by Hunting Creek, Hooff's Run, the Potomac River, and approximately the line which would become Cameron Street. At the opening of Virginia's 1748–49 legislative session, there was a petition submitted in the House of Burgesses on November 1, 1748, that the "inhabitants of Fairfax (Co.) praying that a town may be established at Hunting Creek Warehouse on Potowmack River," since Hugh West was the owner of the warehouse. The petition was introduced by Lawrence Washington, the representative for Fairfax County, the son-in-law of William Fairfax, and a founding member of the Ohio Company. To support the company's push for a town on the river, Lawrence's younger brother George Washington, an aspiring surveyor, made a sketch of the shoreline touting the advantages of the tobacco warehouse site.[12]

The age distribution was 16.8% under the age of 18, 9.2% from 18 to 24, 43.5% from 25 to 44, 21.5% from 45 to 64, and 9.0% who were 65 years of age or older. The median age was 34 years. For every 100 females, there were 93.5 males. For every 100 females aged 18 and over, there were 91.7 males.

Polyurethanes combine the elastic properties of elastomers with melt processible thermoplastic materials. Seals made of polyurethanes provide excellent wear and anti-extrusion characteristics. Special sealing polyurethanes grades have a superior compression set and relaxation performance as well as temperature stability compared to commodity industrial grades. Due to their elasticity and flexibility, they are easy to install.

The demographics of the public school system contrast with those of the city. In 2008, only 14% of the students at Francis C. Hammond Middle School were non-Hispanic whites, compared to about 60% when looking at the city as a whole. 27% were of Hispanic descent, and 48% were black. About 9% of the school was of Asian descent. In 2004, 62% of school-going children received free lunches; by 2008, that number had decreased to 56%.[132] At George Washington Middle School, 41% of students are non-Hispanic whites, 34% were Hispanic, 21% was black, and 2% of the students were Asian; 52% of students received free lunch.[133] Alexandria City High School follows this trend as well; 23% of the students were classified as non-Hispanic whites, 25% as Hispanic, 44% as black, and 7% of the school was Asian; 47% of all students received free lunch.[134]

Which of these are necessary nutrients in food? A) High fructose corn syrup B) Sweeteners and food coloring C) Proteins and minerals D) preservatives

Like the rest of Northern Virginia and Central Maryland, present-day Alexandria has been influenced by its proximity to the U.S. capital. It is largely populated by professionals working in the federal civil service, in the U.S. military, or for one of the many private companies which contract to provide services to the U.S. federal government. The city's largest employers include the U.S. Department of Defense and the Institute for Defense Analyses. Alexandria is the highest-income independent city in Virginia.

GSC Power-Division Viton Valve Stem Seals for the Mitsubishi 4G63T 6.6mm valve stem.

Alexandria adopted a council-manager form of government by way of referendum in 1921. This type of government empowers the elected City Council to pass legislation and appoint the City Manager. The City Manager is responsible for overseeing the city's administration.

Hydraulic cylinder seals are used to seal the opening (clearance gap) between various components in the hydraulic cylinder. Fig.3 shows an example of the seal and guide components of a heavy duty cylinder.

HydraulicCup Seals

Light duty cylinders are typically cylinders used for stationary equipment, indoors in a factory environment and may be characterised by:

In 1861 and 1862, escaped African American slaves poured into Alexandria. Safely behind Union lines, the cities of Alexandria and Washington offered comparative freedom and employment. Alexandria became a major supply depot and transport and hospital center for the Union army.[28] Until the Emancipation Proclamation of January 1, 1863, escaped slaves legally remained the property of their owners. Therefore, they were labeled contrabands to avoid returning them to their masters. Contrabands worked for the Union army in various support roles.

In the Virginia General Assembly, Alexandria is represented in the House of Delegates as part of the 3rd district, 4th district, and 5th district.[117] In the Virginia Senate, the city is represented as part of the 39th district.[118] At the federal level, Alexandria is part of Virginia's 8th congressional district, represented by Democrat and Alexandria resident Don Beyer, elected in 2014. The state's senior member of the United States Senate is Democrat Mark Warner, first elected in 2008. The state's junior member of the United States Senate is Democrat Tim Kaine, first elected in 2012.

In the summer of 1608, English settler John Smith explored the Potomac River and came into contact with the Patawomeck (loosely affiliated with the Powhatan) and Doeg tribes who lived on the Virginia side, as well as on Theodore Roosevelt Island, and the Piscataway (also known as the Conoy), who resided on the Maryland side.[7] On this visit, Smith recorded the presence of a settlement called Assaomeck near the south bank of what is now Hunting Creek.[8]

A cylinder which can only push but not pull is referred to as a single-acting cylinder. High pressure fluid is pumped into the extend chamber (Fig.2: A) and acts on the piston to push the piston rod out. An external force is required to return the cylinder to the retracted position. A typical single-acting cylinder can be found on a forklift truck where the load of the fork assembly (tines and carriage) enacted by gravity pushes the cylinder back into the retracted position. Multi-stage cylinders (also referred to as telescopic cylinders) have two or more piston rods in a coaxial arrangement to achieve a greater extended length compared to the retracted length.

Sealing Australia are distributors of SKF Fluid Power Seals. SKF’s state-of-the-art materials, production capabilities and R&D place them at the forefront of sealing technology and Sealing Australia are proud to have them on board.

The Alexandria Fire Department (AFD) is the city's fire protection and emergency medical services provider and is led by Fire/EMS Chief Corey A. Smedley.[130] The AFD operates 10 stations throughout the city and employs over 300 fire and EMS professionals.

Whether for decorative elements, comfort, or function, our pillows embody the luxe and leisure of Cartagena. The La Popa Oversized Lumbar Pillow perfectly ...

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AUB has summarized the size table of the most widely used ball bearings based on many years of bearing manufacturing experience.

The addressing system in Alexandria is not uniform and reflects the consolidation of several originally separate communities into a single city. In Old Town Alexandria, building numbers are assigned north and south from King Street and west (only) from the Potomac River. In the areas formerly in the town of Potomac, such as Del Ray and St. Elmo, building numbers are assigned east and west from Commonwealth Avenue and north (only) from King Street. In the western parts of the city, building numbers are assigned north and south from Duke Street.

Fluid power systems transfer and utilise mechanical power through a working fluid. Energy is transmitted, stored and used through the transfer and pressure of fluids. By utilising differential surface areas acted upon by the pressure of the working fluid, a mechanical advantage can be achieved. There are two main types of fluid power systems:

Generally these changes are accelerated by higher temperatures. To avoid these changes and the resulting damage to seal function and life, careful consideration should be taken to ensure compatibility between fluid and all seal materials, as well as the temperature and mechanical loads on the seal material.

17255. (a) It is the intent of the Legislature, in enacting this section, to recognize the state's General Fund budget deficit accumulated prior to July ...