title: Sukhoi Superjet 100

text: Sukhoi delivered only three SSJs in the first half of 2019; its financial results show a sevenfold drop in aircraft sales revenue and a fourfold drop in overall sales revenue, resulting in a 32% increase in its net loss. The company needs to achieve a production rate of 32 to 34 aircraft per year to make a profit, though demand for Russian models in the 60–120 seat category is forecast to be only 10 aircraft per year over a 20-year period. In the short-term, the company's main hope is that Aeroflot will firm up its 2018 preliminary agreement for 100 SSJs.


title: Sukhoi Superjet 100

text: Yamal Airlines, the second-largest Russian SSJ operator, announced the cancellation of its order for 10 further SSJs, citing high servicing costs. Of 30–40 SSJs owned by Aeroflot, only 10 are reportedly usable at a time due to maintenance problems. Aeroflot cancelled approximately 50 Superjet flights in the week following the Flight 1492 accident. "Kommersant" cited industry sources as saying the Superjet 100 had lower dispatch reliability than Airbus and Boeing aircraft in the airline's fleet historically and attributed a rise in cancellations to "increased safety measures" at Aeroflot while the accident is investigated. On 4 June, the Russian Federal Air Transport Agency (Rosaviatsiya) ordered carriers to perform one-time inspections of the SSJ, including a general check of the aircraft's condition and verification of aircraft and engine logs, by 25 June.


title: Sukhoi Superjet 100

text: A total of 12 jets were delivered in 2020 to the following operators: Rossiya Airlines, Azimuth Airlines, Red Wings Airlines.


title: Sukhoi Superjet 100

text: The sole remaining western operator, Interjet, down by the end of November 2020 to just four operational SSJ100s, quit flying in December of 2020 and entered bankruptcy in April of 2021. Part of Interjet’s plan was to try to return its 22 SSJ-100s to Sukhoi to cancel its debt, and resume flying with 10 Airbus A320 aircraft.


title: Sukhoi Superjet 100

text: In December 2020, Rossiya Airlines announced that it intends to operate 66 Superjets by the end of 2021, transferred from its parent company Aeroflot which currently has 54 SSJs.


title: Sukhoi Superjet 100

text: Three variants were initially planned, seating 60, 78 and 98 passengers: the RRJ-60, RRJ-75 and RRJ-95, respectively. By 2007, the RRJ-60 had been dropped, to focus on the 98-seater, with the 78-seater to follow. The basic version was certified by the EASA on 3 February 2012, the RRJ-95LR100 with an MTOW increased from and the RRJ-95B100 with thrust increased from the SaM146-1S17 of -1S18s were added on 7 March 2017.


title: Sukhoi Superjet 100

text: In 2011, the Russian Ministry of Industry and Trade mentioned the stretched Superjet 130NG, seating 130.


title: Sukhoi Superjet 100

text: It would have an aluminium fuselage and composite wings. The new materials were intended to reduce weight by 15-20%, increase service life by 20–30% and reduce operating costs by 10–12%.


title: Sukhoi Superjet 100

text: In 2013, funding was planned to start in 2016 for production from 2019 to 2020. It would have used a derivative of the Irkut MC-21 composite wing and Pratt & Whitney PW1000G engines. The 130-seat stretch would have been known as the Sukhoi Superjet 130NG. It would have competed with the Airbus A220 and Embraer E-Jet E2 family.


title: Sukhoi Superjet 100

text: In 2016, a shorter stretch seating up to 120, using larger wings but the same engines and tail, was planned for introduction in 2020.


title: Sukhoi Superjet 100

text: In 2017, with a business plan for 150 aircraft, a go-ahead for the NG 130-seat stretch depended on the availability of engines with sufficient thrust and was due by the end of the year.


title: Sukhoi Superjet 100

text: The aircraft could carry up to 120 passengers with the existing engines, and up to 125 passengers with airframe continuous improvements; PowerJet could certify a thrust increase of 2% within three years. Sukhoi was to decide by the first quarter of 2018 whether to launch first a shortened 75-seat or a stretched variant needing higher thrust SaM146s or an alternative engine.


title: Sukhoi Superjet 100

text: At the February 2018 Singapore Air Show, Sukhoi announced a possible 75-seat shrink, to enter service in 2022.


title: Sukhoi Superjet 100

text: With a smaller, optimised aluminium or composite wing, it would be powered by Pratt & Whitney PW1200Gs, detuned SaM146s or Aviadvigatel PD-14 derived PD-7s.


title: Sukhoi Superjet 100

text: The shorter fuselage would be lighter and it would fall within US scope clauses, but would require Western service and support experience.


title: Sukhoi Superjet 100

text: Demand for such jets is 200–300 in Russia and up to 3,000 overseas; introduction could slip to early 2023.


title: Sukhoi Superjet 100

text: As Sukhoi and Irkut may be consolidated into United Aircraft, some structures and avionics could be closer to the Irkut MC-21 for commonality.


title: Sukhoi Superjet 100

text: A unified platform with identical controls would ease pilot conversions; S7 Airlines committed to 75 aircraft.


title: Sukhoi Superjet 100

text: In July 2018, a composite wing was preferred and a 3-metre test section will be manufactured and tested. The variant would retain the SaM146 and empty weight should be reduced by 12–15%.


title: Sukhoi Superjet 100

text: In 2018, serial production was planned for 2025, four years after design approval. By 2019, the priority had shifted to the replacement of Western parts on the SSJ100 so that the aircraft can be sold to US-sanctioned countries such as Iran. S7 Airlines, which had committed to 75 of the shortened aircraft, may seek alternatives from Bombardier or Embraer. In September 2019 the owner of S7, Vladislav Filev, confirmed his understanding that the SSJ75 project had been abandoned. He explained that S7 had insisted on the participation of its own experts in the test programme, and had demanded the replacement of the composite floor that showed insufficient fire resistance in the Sheremetyevo crash, together with a redesign of the wheel wells.


title: Sukhoi Superjet 100

text: By August 2016, 133 SSJ100s were in operation with eight airlines and five governmental and business aviation organizations.


title: Sukhoi Superjet 100

text: In October 2017, there were 105 SSJ100s in service worldwide: some used by government bodies such as the Royal Thai Air Force and Kazakh government agencies.


title: Sukhoi Superjet 100

text: The fleet had logged 230,000 flights in 340,000 hours since its commercial operations debuted in 2011.


title: Sukhoi Superjet 100

text: At least 30 SSJ100s were to be delivered in 2017, with 38 planned for 2018 and 37 for 2019. In May 2018, ten years after its first flight, the fleet of 127 have logged over 275,000 commercial flights and 420,000 hours. In September 2018, it had logged over 300,000 revenue flights lasting 460,000 hours.


title: Ron White

text: Ron White (born December 18, 1956) is an American stand-up comedian, actor and author, best known as a charter member of the Blue Collar Comedy Tour. Nicknamed "Tater Salad", he is the author of the book "I Had the Right to Remain Silent But I Didn't Have the Ability", which appeared on the "New York Times" best seller list.


title: Ron White

text: White was born in Fritch, Texas on December 18, 1956. He joined the U.S. Navy at age 17 and served on the auxiliary rescue and salvage ship USS "Conserver" near the end of the Vietnam War. Before pursuing comedy professionally, White briefly lived in Mexico, where he bought a pottery factory.


title: Ron White

text: From January 2000 through March 2003, White toured with Jeff Foxworthy, Bill Engvall, and Larry the Cable Guy as part of the Blue Collar Comedy Tour – a show that sold out across the United States in over 90 cities and grossed over $15 million. He made seven guest appearances on "Blue Collar TV". In 2005, The WB Television Network aired the pilot for "The Ron White Show", a variety show that combined a number of celebrity cameos, cartoons, and sketches. He taped several episodes of "The Gong Show with Dave Attell" as one of the celebrity judges. White has appeared in the TV shows "Kath & Kim", "Reno 911!", "12 Miles of Bad Road", the films "Sex and the City 2" and "Horrible Bosses", and a cameo in a Rascal Flatts music video, "Why Wait".


title: Ron White

text: White is known for drinking Scotch as part of his act, as well as smoking cigars or cigarettes. He stated during his "You Can't Fix Stupid" show, "Somebody asked what I was drinking. If the company that made the stuff I was drinking was paying me, I'd have it in their bottle and not mine. But it's the kind of scotch that people drink that are going to die penniless. It's good though!" In 2009, Comedy Central released White's stand up DVD "Behavioral Problems".


title: Ron White

text: In 2010, Ron White and producer Michael Blakey formed Organica Music Group (OMG), a label that promotes both emerging and established musicians and comedians. OMG indicated that it would release all of White's future DVDs and CDs. In November 2015, White announced that he was running for President of the United States as an independent candidate in 2016. In 2016, White starred as Phil, veteran road manager for the fictional Staton-House Band, in the Showtime series "Roadies".


title: Ron White

text: White was married to Lori Brice from 1981 to 1993 and they had one son, Marshall. He was later married to Barbara Dobbs from 2004 to 2008. In 2013, he married singer Margo Rey; as of 2017 the two are no longer together, with White claiming that they were never legally married. On August 6, 2019, a ruling came down in L.A. Superior Court where a judge sided with Rey and declared the couple was in a common-law marriage under Texas law.


title: Ron White

text: White stopped drinking alcohol sometime in early 2021. He credits the consultation of a hypnotherapist and the use of ayahuasca with his abstinence.


title: Ron White

text: April 27, 2009, was designated "Ron White Day" in the State of Texas by Texas legislative officials. White received the Armed Forces Foundation's "Patriot Award" in March 2009 for his work in raising money to help wounded soldiers. He also held benefit shows for Hurricane Katrina relief. He was Grammy-nominated for Best Comedy Album in 2007 & 2014.


title: City of Manchester Stadium

text: The City of Manchester Stadium in Manchester, England, also known as the Etihad Stadium for sponsorship reasons, is the home of Premier League club Manchester City F.C., with a domestic football capacity of 53,400, making it the 6th-largest in England and tenth-largest in the United Kingdom.


title: City of Manchester Stadium

text: Built to host the 2002 Commonwealth Games, the stadium has since staged the 2008 UEFA Cup Final, England football internationals, rugby league matches, a boxing world title fight, the England rugby union team's final group match of the 2015 Rugby World Cup and summer music concerts during the football off-season.


title: City of Manchester Stadium

text: The stadium, originally proposed as an athletics arena in Manchester's bid for the 2000 Summer Olympics, was converted after the 2002 Commonwealth Games from a 38,000 capacity arena to a 48,000 seat football stadium at a cost to the city council of £22 million and to Manchester City of £20 million. Manchester City F.C. agreed to lease the stadium from Manchester City Council and moved there from Maine Road in the summer of 2003.


title: City of Manchester Stadium

text: The stadium was built by Laing Construction at a cost of £112 million and was designed and engineered by Arup, whose design incorporated a cable-stayed roof structure which is separated from the main stadium bowl and suspended entirely by twelve exterior masts and attached cables. The stadium design has received much praise and many accolades, including an award from the Royal Institute of British Architects in 2004 for its innovative inclusive building design and a special award in 2003 from the Institution of Structural Engineers for its unique structural design.


title: City of Manchester Stadium

text: In August 2015, a 7,000 seat third tier on the South Stand was completed, in time for the start of the 2015–16 football season. The expansion was designed to be in keeping with the existing roof design.


title: City of Manchester Stadium

text: Plans to build a new stadium in Manchester were formulated before 1989 as part of the city's bid to host the 1996 Summer Olympics. Manchester City Council submitted a bid that included a design for an 80,000-capacity stadium on a greenfield site west of Manchester city centre. The bid failed and Atlanta hosted the Games. Four years later the city council bid to host the 2000 Summer Olympics, but this time focusing on a brownfield site east of the city centre on derelict land that was the site of Bradford Colliery, known colloquially as Eastlands. The council's shift in focus was driven by emerging government legislation on urban renewal, promising vital support funding for such projects; the government became involved in funding the purchase and clearance of the Eastlands site in 1992.


title: City of Manchester Stadium

text: For the February 1993 bid the city council submitted another 80,000-capacity stadium design produced by design consultants Arup, the firm that helped select the Eastlands site. On 23 September 1993, the games were awarded to Sydney, but the following year Manchester submitted the same scheme design to the Millennium Commission as a "Millennium Stadium", only to have this proposal rejected. Undeterred, Manchester City Council subsequently bid to host the 2002 Commonwealth Games, once again proposing the same site along with downsized stadium plans derived from the 2000 Olympics bid, and this time were successful. In 1996, this same planned stadium competed with Wembley Stadium to gain funding to become the new national stadium, but the money was used to redevelop Wembley.


title: City of Manchester Stadium

text: After successful athletics events at the Commonwealth Games, conversion into a football venue was criticised by athletics figures such as Jonathan Edwards and Sebastian Coe as, at the time, the United Kingdom still lacked plans for a large athletics venue due to the capability of installing an athletics track having been dropped from the designs for a rebuilt Wembley Stadium. Had either of the two larger stadium proposals developed by Arup been agreed for funding, then Manchester would have had a venue capable of being adapted to hosting large-scale athletics events through the use of movable seating.


title: City of Manchester Stadium

text: Sport England wished to avoid creating a white elephant, so they insisted that the City Council agree to undertake and fund extensive work to convert "CoMS" from a track and field arena to a football stadium, thereby ensuring its long-term financial viability. Sport England hoped either Manchester City Council or Manchester City F.C. would provide the extra £50 million required to convert the stadium to a 65,000 seater athletics and footballing venue with movable seating. However, Manchester City Council did not have the money to facilitate movable seating and Manchester City were lukewarm about the idea. Stadium architects Arup believed history demonstrated that maintaining a rarely used athletics track often does not work with football – and cited examples such as the Stadio delle Alpi and the Olympic Stadium with both Juventus and Bayern Munich moving to new stadiums less than 40 years after inheriting them.


title: City of Manchester Stadium

text: The stadium's foundation stone was laid by Prime Minister Tony Blair in December 1999, and construction began in January 2000. The stadium was designed by Arup and constructed by Laing Construction at a cost of approximately £112 million, £77 million of which was provided by Sport England, with the remainder funded by Manchester City Council. For the Commonwealth Games, the stadium featured a single lower tier of seating running around three sides of the athletics track, and second tiers to the two sides, with an open-air temporary stand at the northern end; initially providing a seating capacity for the Games of 38,000, subsequently extended to 41,000 through the installation of additional temporary trackside seating along the east and south stands.


title: City of Manchester Stadium

text: The first public event at the stadium was the opening ceremony of the 2002 Commonwealth Games on 25 July 2002. Among the dignitaries present was Queen Elizabeth II who made a speech, delivered to her in an electronic baton, and 'declared the Commonwealth Games open'. During the following ten days of competition, the stadium hosted the track and field events and all the rugby sevens matches. Sixteen new Commonwealth Games track and field records (six men's and ten women's) were set in the stadium. Prior to the 2012 Summer Olympics held in London, the 2002 Games was the largest multi-sport event ever to be staged in the United Kingdom, eclipsing the earlier London 1948 Summer Olympics in numbers of teams and competing athletes (3,679), and it was the world's first multi-sport tournament to include a limited number of full medal events for elite athletes with a disability (EAD). In terms of number of participating nations, it is still the largest Commonwealth Games in history, featuring 72 nations competing in 281 events across seventeen (fourteen individual and three team) sports.


title: City of Manchester Stadium

text: Sections of the track were removed and relaid at other athletics venues, and the internal ground level was lowered to make way for an additional tier of seating, on terracing already constructed then buried for the original configuration. The three temporary stands with a total capacity of 16,000 were dismantled, and replaced with a permanent structure of similar design to the existing one at the southern end. This work took nearly a year to complete and added 23,000 permanent seats, increasing the capacity of the converted stadium by 7,000 to approximately 48,000. Manchester City F.C. moved to the ground in time for the start of the 2003–04 season. The total cost of this conversion was in excess of £40 million, with the track, pitch and seating conversion being funded by the city council at a cost of £22 million; and the installation of bars, restaurants and corporate entertainment areas throughout the stadium being funded by the football club at a cost of £20 million. The Games had made a small operating surplus, and Sport England agreed that this could be reinvested in converting the athletics warm-up track adjacent to the main stadium into the 6,000 seat Manchester Regional Arena at a cost of £3.5 million.


title: City of Manchester Stadium

text: The stadium is owned by Manchester City Council and leased by the football club on a 'fully repairing' basis. All operating, maintenance and future capital costs are borne by the club; who consequently receive all revenues from stadium users. The 2008 takeover made the football club one of the wealthiest in the world, prompting suggestions that it could consider buying the stadium outright. Manchester City signed an agreement with Manchester City Council in March 2010 to allow a £1 billion redevelopment led by architect Rafael Viñoly.


title: City of Manchester Stadium

text: During the 2010 closed season the football pitch and hospitality areas were renovated, with a £1 million investment being made in the playing surface so that it is better able to tolerate concerts and other events without damage. In October 2010, Manchester City renegotiated the stadium lease, obtaining the naming rights to the stadium in return for agreeing to now pay the City Council an annual fixed sum of £3 million where previously it had only paid half of the ticket sales revenue from match attendances exceeding 35,000. This new agreement occurred as part of a standard five-year review of the original lease and it amounts to an approximate £1 million annual increase in council revenues from the stadium.


title: City of Manchester Stadium

text: During 2011–14, the club sold all 36,000 of its allocated season tickets each season and experienced an average match attendance that is very close to its maximum seating capacity (see table in subsequent section). Consequently, during the 2014–15 season, an expansion of the stadium was undertaken. The South Stand was extended with the addition of a third tier which, in conjunction with an additional three rows of pitch side seating, increased stadium capacity to approximately 55,000. Construction commenced on the South Stand in April 2014 and was completed for the start of the 2015–16 season.


title: City of Manchester Stadium

text: A final phase of expansion, which received planning approval at the same time as the others but remains unscheduled, would have added a matching third tier of seats to the North Stand. In November 2018 the club consulted with season ticket holders on possible alternative configurations for this expansion; including proposals for a still larger two-tier North Stand without executive boxes or corporate hospitality lounges, and possibly with areas convertible to safe standing. The full length of the second tiers in the East and West stands would then be reconfigured as premium seating associated with new hospitality bar areas. Depending on the preferred design option, this final phase could bring the stadium's total seating capacity up to approximately 63,000, making the Etihad Stadium the nation's third largest capacity club ground. Behind Old Trafford and (potentially) the London Stadium, but marginally greater than Tottenham Hotspur Stadium.


title: City of Manchester Stadium

text: When planning the development, Manchester City Council required a sustainable landmark structure that would be an icon for the regeneration of the once heavily industrialised site surrounding Bradford Colliery, as well as providing spectators with good sightlines in an "atmospheric" arena. Arup designed the stadium to be "an intimate, even intimidating, gladiatorial arena embodying the atmosphere of a football club" with the pitch six metres below ground level, a feature of Roman gladiatorial arenas and amphitheatres. The attention to detail, often absent in stadium design, has been remarked upon, including the cigar-shaped roof supports with blue lighting beacons, sculpted rainwater gutters, poly-carbonate perimeter roof edging and openable louvres to aid pitch grass growth with similarities also made to high-tech architecture.


title: City of Manchester Stadium

text: The toroidal-shaped stadium roof is held together by a tensioned system, which has been described as "ground-breaking" by "New Steel Construction" magazine. The stadium's architectural focal point is the sweeping roof and support masts which are separate from the concrete bowl. A catenary cable is situated around the inner perimeter of the roof structure which is tied to the masts via forestay cables. Backstay cables and corner ties from the masts are connected to the ground to support the structure. With the expansion of the South Stand in 2015 to accommodate a third tier of seating, the original south end roof was dismantled; but with the southern masts and corner ties remaining, so as to continue to tie the catenary cable which now runs below the new roof. The new higher South Stand roof is a separate structure, with its own set of braced masts and cables; and it is expected that a counterpart arrangement will be adopted for the proposed North Stand expansion.


title: City of Manchester Stadium

text: Cables are attached to the twelve masts circling the stadium with rafters and purlins for additional rigid support. The cigar-shaped masts double as visual features, with the highest at . Access to the upper tiers of seats is provided by eight circular ramps with conical roofs resembling turrets above which eight of the twelve masts rise up providing the support structure for the roof.


title: City of Manchester Stadium

text: The roof of the south, east and west stands built for the athletics stadium configuration was supported by the cable net system. The temporary open stand at the north end was built around the masts and tie down cables that would ultimately support the roof of the North Stand. After the games the track and field were excavated. The temporary bleachers at the north end were removed and the North Stand and lower tier of seats constructed on the prepared excavation. The North Stand roof was completed by adding rafters, purlins and cladding.


title: City of Manchester Stadium

text: The stadium has facilities for players and match officials in a basement area below the west stand, which also contains a kitchen providing meals for up to 6,000 people on match days, press rooms, ground staff storage, and a prison cell. The stadium also has conference facilities and is licensed for marriage ceremonies. Fitting out of the hospitality suites, kitchens, offices, and concourse concessions was accomplished by KSS Architects, and included the installation of the communications cabling and automatic access control system.


title: City of Manchester Stadium

text: The stadium's interior comprises a continuous oval bowl, with three tiers of seating at the sides, and two tiers at each end. Entry by patrons is gained by contactless smart card rather than traditional staffed turnstiles. The system can admit up to 1,200 people per minute through all entrances. A service tunnel under the stadium provides access for emergency vehicles and the visiting team's coach to enter the stadium directly. Once inside the stadium patrons have access to six themed restaurants, two of which have views of the pitch, and there are 70 executive boxes above the second tier of seating in the north, west and east stands. The stadium is equipped with stand-by generators should there be an electrical mains failure. These are capable of keeping the stadium electrics running as well as the floodlights at 800 lux, the minimum level stipulated by FIFA to continue to broadcast live football.


title: City of Manchester Stadium

text: To create the optimum grass playing surface in the stadium bowl, the roof was designed to maximise sunlight by using a ten-metre band of translucent polycarbonate at its periphery. Additionally, each of the corners of the stadium without seating have perforated walls with moveable louvres that can be adjusted to provide ventilation of the grass and general airflow through the stadium. Drainage and under-pitch heating were installed to provide optimum growing conditions for the grass. The pitch has a UEFA standard dimension of . and is covered with natural grass reinforced by artificial fibres made by Desso. The field of play is lit by 218 2000-watt floodlights, consuming a total of 436,000 watts. The grass playing surface is recognised as being one of the best in English football, and has been nominated five times in the last nine seasons for best Premier League pitch, an accolade it won in 2010–11 among other awards.


title: City of Manchester Stadium

text: The stadium was named the City of Manchester Stadium by Manchester City Council before construction began in December 1999, but has a number of commonly used alternatives. City of Manchester Stadium is abbreviated to CoMS when written and spoken. Eastlands refers to the site and the stadium before they were named SportCity and CoMS respectively, and remains in common usage for both the stadium and the whole complex, as does SportCity but with less frequency. The stadium was also officially referred to as Manchester City Stadium for the 2015 Rugby World Cup. The football club, under its new ownership, renegotiated its 250-year lease with the city council in October 2010, gaining the naming rights in return for a substantial increase in rent. The stadium was renamed the Etihad Stadium by the club in July 2011 as part of a ten-year agreement with the team kit sponsors Etihad Airways. The agreement encompasses sponsorship of the stadium's name, extends the team kit sponsorship for ten years, and relocated the club's youth academy and training facilities to the City Football Academy onto the Etihad Campus development across the road from the stadium.


title: City of Manchester Stadium

text: Despite being a continuous oval bowl, each side of the stadium is named in the manner of a traditional football ground. All sides were initially named by compass direction (North Stand and South Stand for the ends, East Stand and West Stand for the sides). In February 2004, after a vote by fans, the West Stand was renamed the Colin Bell Stand in honour of the former player. The vote was almost cancelled (and the stand instead named after Joe Mercer) due to suspicions it had been hijacked by rival fans who wished to dub the renamed stand The Bell End. However, core supporters of the club made it clear they still wished the stand named after their hero. The East Stand is unofficially known by fans as the Kippax as a tribute to the very vocal east stand at the club's Maine Road ground.


title: City of Manchester Stadium

text: The North Stand is the only part of the stadium built after the Commonwealth Games, during the stadium's conversion. The temporary unroofed north stand it replaced had been dubbed the New Gene Kelly Stand by supporters, a reference to the unroofed corner between the Kippax and the North Stand at the club's former Maine Road home, because, being exposed to the elements, they frequently found themselves "singing in the rain". Commencing season 2010–11, seating in the North Stand has been restricted to only supporters accompanied by children, resulting in this end of the ground now being commonly referred to as the Family Stand. Although the North Stand has never been officially renamed and is still frequently referenced that way, most external ticketing offices and stadium guides, in addition to the club itself, now preferentially label and refer to this section of the ground as the Family Stand when discussing seating and ticket sales. Supporters initially dubbed the South Stand the Scoreboard End (the former name of the North Stand at Maine Road), and it houses the majority of City's more vocal fans. Supporters of visiting teams are also normally allocated seats in this stand, as it has ready access from the visitor supporter coach park. From 2003 to 2006, the South Stand was renamed the Key 103 Stand for sponsorship reasons, though this was largely ignored by regular patrons. The November 2018 consultation exercise on further expansion options envisages the North Stand then becoming the Home End, with no corporate hospitality areas, a greatly extended second tier, "affordable" ticket prices and possible areas capable of conversion to safe standing. The singing area would then be in the North Stand, and the Family Stand would be relocated elsewhere in the Stadium.


title: City of Manchester Stadium

text: The stadium is the centrepiece of SportCity, which includes several other nationally important sporting venues. Adjacent to the stadium is the Manchester Regional Arena, which served as a warm-up track during the Commonwealth Games and is now a 6,178-capacity venue that hosts national athletics trials, but has previously also hosted the home games of both the Manchester City women's team and the club's under-21 reserve team. The Regional Arena has regularly hosted the AAA Championships and Paralympic World Cup, and is currently the home ground of amateur rugby league side Manchester Rangers.


title: City of Manchester Stadium

text: The National Squash Centre and the National Cycling Centre, which includes both the Manchester Velodrome and the National Indoor BMX Arena, are all a short distance from the stadium. The Squash Centre, which has hosted the British National Squash Championships since 2003 was added to the SportCity complex for the Commonwealth Games along with CoMS. The Velodrome, another showpiece venue used to stage all the track cycling events for the Games, was already in place and had been home to British Cycling, the governing body for cycling in Britain, since it was built in 1994, as part of Manchester’s unsuccessful 2000 Olympics bid. Prior to the completion of the Lee Valley VeloPark for the 2012 Summer Olympics, the Velodrome had been the only indoor Olympic-standard track in the United Kingdom. The collocated BMX Arena houses the United Kingdom’s only permanent indoor BMX track and provides seating for up two thousand spectators. It was added to the National Cycling Centre at SportCity in 2011.


title: City of Manchester Stadium

text: Other major sporting and sport-related venues located in SportCity in the immediate vicinity of the Etihad Stadium, all legacies of the 2002 Commonwealth Games are the English Institute of Sport, west of the stadium, adjacent to the southwest corner of the Regional Arena; the Manchester Regional Tennis Centre, adjacent to the north end of the stadium; and the Manchester Tennis & Football Centre, also adjacent to the stadium, which is operated and administered by the Manchester Sport and Leisure Trust.


title: City of Manchester Stadium

text: Between 11 March (Commonwealth Day) and 10 August 2002, as part of the preparations for the upcoming Commonwealth Games and to celebrate Her Majesty the Queen's Golden Jubilee, a national Spirit of Friendship Festival was organised. On 9 July, a few weeks before the Games began, a sculpture outside the new national headquarters of the English Institute of Sport at SportCity was unveiled by the middle-distance runner Steve Cram. This sculpture, commissioned in late 2001, was created in a little over eight weeks by Altrincham-based artist, Colin Spofforth, who had submitted to Manchester City Council his idea for a heroic-sized sculpture of a sprinter as a means of celebrating the beauty, power and determination of the competing athletes. Reaching thirty feet high, weighing seven tonnes, and titled "The Runner", this unique larger-than-life bronze statue of a male sprinter surmounting a bronze globe was, at the time, the United Kingdom's largest sporting sculpture. It depicts the very moment the runner leaves the blocks once the starter's gun has fired.


title: City of Manchester Stadium

text: From 2005 to 2009 a Thomas Heatherwick sculpture, "B of the Bang", was situated to the southeast of the stadium at the junction of Ashton New Road and Alan Turing Way. Built after the Commonwealth Games to commemorate them, it was the tallest sculpture in the United Kingdom. However, numerous structural problems led to the 184 ft. sculpture being dismantled in 2009 for safety reasons. In 2014, money recovered by the Manchester City Council as a result of lengthy legal battles consequent to this debacle was used to fund a new £341,000 public sculpture a few hundred yards further south.


title: City of Manchester Stadium

text: The first public football match at the stadium was a friendly between Manchester City and Barcelona on 10 August 2003. Manchester City won the game 2–1, with Nicolas Anelka scoring the first ever goal in the stadium.


title: City of Manchester Stadium

text: The first competitive match followed four days later, a UEFA Cup match between Manchester City and Welsh Premier League side The New Saints, which City won 5–0 with Trevor Sinclair scoring the first competitive goal in the stadium. Having started the Premier League season with an away match, Manchester City's first home league fixture in the new stadium was on 23 August, a game drawn 1–1 with Portsmouth, with Pompey's Yakubu scoring the first league goal in the stadium.


title: City of Manchester Stadium

text: 2011–12 saw the Etihad Stadium play host to the setting of a number of new club and Premier League footballing records, such as the club becoming the first ever team to win eleven of its opening twelve games in a Premier League season, and going on to remain unbeaten at the Etihad Stadium in all nineteen of the Premier League games played there. The club's record of 55 home points out of a possible 57 at the stadium is a joint best Premier League record, and the club's record of twenty consecutive home wins at the stadium (going back to the end of the previous season) also set a new Premier League record in March 2012.


title: City of Manchester Stadium

text: The record football attendance at the stadium not involving its host team Manchester City is 43,878, which was set at the 2008 UEFA Cup Final game between Zenit Saint Petersburg and Rangers on 14 May 2008. As is customary for such games, the then 47,715 maximum physical capacity of the stadium had been reduced by UEFA to around 44,000 for this final. However, neither limit would have been able to accommodate the vast number of supporters of the Scottish club, estimated to be in excess of 130,000, that travelled down from Glasgow to Manchester on the day of the game, despite the club's official ticket allocation being just 13,000 and police requests for fans without tickets to stay home. This order of magnitude mismatch between the numbers of travelling fans and those holding tickets ultimately led to a serious public disorder incident in the centre of the city now inextricably associated with this final, despite the fact that the 44,000 or so crowd who watched the game inside the stadium were perfectly well-behaved.


title: City of Manchester Stadium

text: The 2002 Commonwealth Games were deemed a success and the stadium gained critical acclaim for its atmosphere and architectural design. It has won a number of design awards, including the 2004 Royal Institute of British Architects Inclusive Design Award for inclusive building design, the 2003 Institution of Structural Engineers Structural Special Award, and in 2002 a BCI Major Project high commendation was awarded by the British Construction Industry. In July 2014, the stadium was declared one of the United Kingdom's five most iconic structures by the Construction Industry Training Board.


title: City of Manchester Stadium

text: In 2003, initial reception by Manchester City supporters was polarised, with some lukewarm about moving from Maine Road which had a reputation for being one of English football's most atmospheric grounds, whilst others were enthusiastic about the bigger stadium and move back to East Manchester where the club was formed. Since 2010, the club has boasted more than 36,000 season ticket holders each season, which is more than the 35,150 maximum capacity of Maine Road just before the club moved homes.


title: City of Manchester Stadium

text: In a 2007 Premier League survey of fans of each club, the proportion of Manchester City fans assessing their sight lines as 'very good' was the second highest in the Premier League, after the Emirates Stadium.


title: City of Manchester Stadium

text: Opposition fans have generally given positive feedback, with CoMS coming second to Old Trafford in a 2005 poll to find the United Kingdom's favourite football ground. In 2010, the City of Manchester Stadium was the third most visited stadium after Old Trafford and Anfield by overseas visitors.


title: City of Manchester Stadium

text: In the early years of Manchester City's tenure, the stadium suffered from a poor atmosphere, a common problem with newly-opened stadia when compared with traditional football grounds such as Maine Road. In the 2007 Premier League survey, the proportion of Manchester City fans assessing match atmosphere as 'very good' was the second lowest in the Premier League, better only than Middlesbrough's Riverside stadium. The more recent expansion of capacity has been designed with improved atmosphere as a specific objective. Though not based on facts, the stadium is nicknamed 'Emptyhad' by rival fans in reference to poor game-day attendance and atmosphere.


title: City of Manchester Stadium

text: In October 2014, the club received two national VisitFootball awards for the quality of its customer care of Premier League fans visiting the Etihad Stadium during the previous season. VisitFootball, a joint venture between the Premier League and the national tourism board's VisitEngland, has been assessing the care that patrons receive at football grounds since August 2010, and presents annual awards for those clubs who deliver outstanding customer service. Manchester City had been one of the first four clubs to receive an inaugural VisitFootball award in 2011, but in 2014 it was the recipient of both the Club of the Year and Warmest Welcome awards. According to the panel of experts from the football and customer service industries that assess the services and facilities provided at each of the twenty Premier League club stadia, "Manchester City are the gold standard in providing fans with the best matchday experience."


title: City of Manchester Stadium

text: In July 2011, CoMS was renamed the Etihad Stadium, sponsored by Etihad Airways who fought off competition from Ferrostaal and Aabar to gain the stadium naming rights. The lucrative ten-year sponsorship deal included not just the naming rights to the stadium itself but to the whole £200 million complex of football-related facilities into which it was soon to be incorporated. In mid-September 2011, development plans were duly announced for a new state-of-the-art youth academy and training facility, now known as the City Football Academy (CFA) to be built on derelict land adjacent to the stadium and which would include a 7,000 capacity mini-stadium plus fifteen additional outdoor football pitches, six swimming pools and three gyms. The planned CFA facility was not only to become the new home base of the Manchester City first team squad, reserve (under-21 youth) team squad, and all of the Academy younger age group squads, but also the new home of the prior loosely affiliated Manchester City Ladies team (which was re-branded in 2012 as Manchester City Women's F.C. and more formally merged into the Manchester City family of affiliated football teams). Also fully integrated into the new CFA facility would be the parent club's world headquarters.


title: City of Manchester Stadium

text: At the beginning of March 2014, the structural framework for a new pedestrian walkway/footbridge over the junction of Alan Turing Way and Ashton New Road connecting the CFA with the Etihad Stadium was lowered into place. With sponsor Suisse Power & Gas SA having subsequently secured the naming rights, the completed SuisseGas Bridge was officially opened and turned over to Manchester City Council for general public access on 26 November 2014. Twelve days later, the Chancellor of the Exchequer, George Osborne, presided over the official opening of the CFA.


title: City of Manchester Stadium

text: As part of Manchester City's commitment to community outreach in their redevelopment plans for the areas of East Manchester adjacent to the Etihad Stadium, other urban regeneration plans incorporated into the overall Etihad Campus development project include the new £43 million Beswick Community Hub, that includes Connell Sixth Form College; a community leisure centre (with swimming pool, dance studio, health and fitness gym, rugby pitch, and grass sports pitches); and a planned Manchester Institute of Health and Performance. On 26 November 2014, the same day the SuisseGas Bridge was officially opened, a "globally admired" grouping of stainless steel sculptures, consisting of three towering metallic chess pieces called "Dad's Halo Effect" by its internationally acclaimed creator, Ryan Gander, was likewise unveiled to the public. Commissioned by the Manchester City Council to represent both the past industrial and current sporting heritage of this area of east Manchester, the public artwork is located in front of the Connell Sixth Form College, close to the central circus of the Beswick Community Hub, and only a few hundred yards south from where the area's last public sculpture, "B of the Bang", had been situated.


title: City of Manchester Stadium

text: The stadium is 2.5 km east of Manchester city centre. Manchester Piccadilly railway station, which serves mainline trains, is a twenty-minute walk away along a well-lit signposted route that is supervised by stewards close to the ground. Piccadilly station also has a Metrolink tram stop (in the undercroft); from which regular trams along the East Manchester Line to Ashton-under-Lyne serve the stadium and Etihad Campus, with enhanced service frequencies and doubled tram units on matchdays. The Etihad Campus tram stop close to Joe Mercer Way to the immediate north of the stadium opened in February 2013, and handles several thousand travellers each matchday; spectators travelling by tram from Manchester city centre being able to board services at Piccadilly Gardens, the journey taking approximately 10 minutes. The Velopark tram stop also opened in February 2013 and provides access to the southeastern approach to the stadium, as well as closer access to other areas of SportCity such as the Manchester Velodrome and the City Football Academy.


title: City of Manchester Stadium

text: There are many bus routes from the city centre and all other directions which stop at, or close to, SportCity. On match and event days special bus services from the city centre serve the stadium. The site has 2,000 parking spaces, with another 8,000 spaces in the surrounding area provided by local businesses and schools.


title: City of Manchester Stadium

text: Under the terms of its lease, the stadium is able to host non-football events such as concerts, boxing and rugby fixtures at Manchester City's prerogative. Manchester City applied for a permanent entertainment licence in 2012 in a bid to expand the number of non-footballing events at the stadium.


title: City of Manchester Stadium

text: Outside the football season, the stadium hosts annual summer concerts, and is one of the United Kingdom's largest music venues, having a maximum capacity of 60,000 for performances. It was the largest stadium concert venue in England before the new Wembley Stadium was built.


title: City of Manchester Stadium

text: The first concert was a performance by the Red Hot Chili Peppers supported by James Brown in 2004. An Oasis concert at the ground was featured on the DVD, "Lord Don't Slow Me Down" and the band's concert in 2005 set the attendance record of 60,000. Take That released a DVD of their 2006 performance at the stadium, "". Other artists who have played the stadium are U2, Beyoncé, Jay-Z, George Michael, Rod Stewart, Foo Fighters, Pet Shop Boys, Manic Street Preachers, Bastille, Dizzee Rascal, The Futureheads, the Sugababes, Taylor Swift, Sophie Ellis-Bextor, Coldplay, Bruce Springsteen, Muse, Bon Jovi (three times), Robbie Williams, One Direction, The Stone Roses and the Spice Girls.It also hosted Liam Gallagher for his homecoming gig in 2022.


title: City of Manchester Stadium

text: Concerts and boxing matches eventually took their toll on the pitch. In 2008, late post-concert pitch renovation, combined with an early start to the football season, led to the pitch not being ready for the first home fixture, causing the club to play its UEFA Cup first round qualifying match at Barnsley's Oakwell Stadium and a moratorium to be imposed on the staging of non-football events at Eastlands. In May 2010, the club invested in a new pitch and summer concerts resumed in 2011 when Take That played eight nights, with ticket sales totalling approximately 400,000.


title: City of Manchester Stadium

text: CoMS is rated a category 4 stadium by UEFA and has hosted several major football matches in addition to Manchester City's home fixtures. It became the fiftieth stadium to host an England international football match when the English and Japanese national teams played on 1 June 2004. In June 2005, the stadium hosted England's opening game in the UEFA Women's Championship, setting an attendance record of 29,092 for the competition. The stadium also hosted the 2008 UEFA Cup Final, in which Zenit Saint Petersburg defeated Rangers 2–0.


title: City of Manchester Stadium

text: In May 2011, the stadium hosted the Conference National play-off final between AFC Wimbledon and Luton Town; Wimbledon gained promotion to the Football League after beating Luton in a penalty shoot-out. The stadium was used for the play-offs because the 2011 UEFA Champions League Final was due to take place at Wembley on 28 May 2011 and UEFA regulations stipulate the stadium hosting the Champions League final must not be used for other matches during the previous two weeks.


title: City of Manchester Stadium

text: In October 2004, the stadium played host to a rugby league international match between Great Britain and Australia in the Tri-Nations series in front of nearly 40,000 spectators.


title: City of Manchester Stadium

text: The stadium also hosted the Magic Weekend for three consecutive seasons (2012–2014). After a record attendance in 2012 – both for a single day (32,953) and the aggregate for the whole weekend (63,716) – the Etihad Stadium became the venue of choice for this annual rugby league event, setting another attendance record (36,339/64,552) for it in May 2014. However, construction work involved with the expansion of the South Stand caused it to be relocated to St. James' Park, Newcastle, for summer 2015.


title: City of Manchester Stadium

text: On 24 May 2008, Stockport born and twice IBF and IBO light welterweight champion boxer Ricky Hatton defeated Juan Lazcano in a contest billed as "Hatton's Homecoming". The fight was held in front of 56,337 fans, setting a record attendance for a British boxing event post World War II.


title: City of Manchester Stadium

text: On 10 October 2015, the stadium hosted a 2015 Rugby World Cup Pool A match between hosts nation England and Uruguay. England won 60–3 with 50,778 in attendance.


title: Abraham Maslow

text: Abraham Harold Maslow (; April 1, 1908 – June 8, 1970) was an American psychologist who was best known for creating Maslow's hierarchy of needs, a theory of psychological health predicated on fulfilling innate human needs in priority, culminating in self-actualization. Maslow was a psychology professor at Brandeis University, Brooklyn College, New School for Social Research, and Columbia University. He stressed the importance of focusing on the positive qualities in people, as opposed to treating them as a "bag of symptoms". A "Review of General Psychology" survey, published in 2002, ranked Maslow as the tenth most cited psychologist of the 20th century.


title: Abraham Maslow

text: Born in 1908 and raised in Brooklyn, New York, Maslow was the oldest of seven children. His parents were first-generation Jewish immigrants from Kiev, then part of the Russian Empire (now Kyiv, Ukraine), who fled from Czarist persecution in the early 20th century. They had decided to live in New York City and in a multiethnic, working-class neighborhood. His parents were poor and not intellectually focused, but they valued education. He had various encounters with anti-Semitic gangs who would chase and throw rocks at him. Maslow and other young people with his background were struggling to overcome such acts of racism and ethnic prejudice in the attempt to establish an idealistic world based on widespread education and economic justice. The tension outside his home was also felt within it, as he rarely got along with his mother, and eventually developed a strong revulsion towards her. He is quoted as saying, "What I had reacted to was not only her physical appearance, but also her values and world view, her stinginess, her total selfishness, her lack of love for anyone else in the world—even her own husband and children—her narcissism, her Negro prejudice, her exploitation of everyone, her assumption that anyone was wrong who disagreed with her, her lack of friends, her sloppiness and dirtiness...". He also grew up with few friends other than his cousin Will, and as a result "...[He] grew up in libraries and among books." It was here that he developed his love for reading and learning. He went to Boys High School, one of the top high schools in Brooklyn, where his best friend was his cousin Will Maslow. Here, he served as the officer to many academic clubs, and became editor of the Latin Magazine. He also edited "Principia," the school's Physics paper, for a year. He developed other strengths as well:


title: Abraham Maslow

text: Maslow attended the City College of New York after high school. In 1926 he began taking legal studies classes at night in addition to his undergraduate course load. He hated it and almost immediately dropped out. In 1927 he transferred to Cornell, but he left after just one semester due to poor grades and high costs. He later graduated from City College and went to graduate school at the University of Wisconsin to study psychology. In 1928, he married his first cousin Bertha, who was still in high school at the time. The pair had met in Brooklyn years earlier. Maslow's psychology training at UW was decidedly experimental-behaviorist. At Wisconsin he pursued a line of research which included investigating primate dominance behavior and sexuality. Maslow's early experience with behaviorism would leave him with a strong positivist mindset. Upon the recommendation of Professor Hulsey Cason, Maslow wrote his master's thesis on "learning, retention, and reproduction of verbal material". Maslow regarded the research as embarrassingly trivial, but he completed his thesis the summer of 1931 and was awarded his master's degree in psychology. He was so ashamed of the thesis that he removed it from the psychology library and tore out its catalog listing. However, Professor Cason admired the research enough to urge Maslow to submit it for publication. Maslow's thesis was published as two articles in 1934.


title: Abraham Maslow

text: He continued his research at Columbia University on similar themes. There he found another mentor in Alfred Adler, one of Sigmund Freud's early colleagues. From 1937 to 1951, Maslow was on the faculty of Brooklyn College. His family life and his experiences influenced his psychological ideas. After World War II, Maslow began to question the way psychologists had come to their conclusions, and although he did not completely disagree, he had his own ideas on how to understand the human mind. He called his new discipline humanistic psychology. Maslow was already a 33-year-old father and had two children when the United States entered World War II in 1941. He was thus ineligible for the military. However, the horrors of war inspired a vision of peace in him leading to his groundbreaking psychological studies of self-actualizing. The studies began under the supervision of two mentors, anthropologist Ruth Benedict and Gestalt psychologist Max Wertheimer, whom he admired both professionally and personally. They accomplished a lot in both realms. Being such "wonderful human beings" as well, they inspired Maslow to take notes about them and their behavior. This would be the basis of his lifelong research and thinking about mental health and human potential. He extended the subject, borrowing ideas from other psychologists and adding new ones, such as the concepts of a hierarchy of needs, metaneeds, metamotivation, self-actualizing persons, and peak experiences. Maslow was a professor at Brandeis University from 1951 to 1969. He became a resident fellow of the Laughlin Institute in California. In 1967, Maslow had a serious heart attack and knew his time was limited. He considered himself to be a psychological pioneer. He gave future psychologists a push by bringing to light different paths to ponder. He built the framework that later allowed other psychologists to conduct more comprehensive studies. Maslow believed that leadership should be non-intervening. Consistent with this approach, he rejected a nomination in 1963 to be the president of the Association for Humanistic Psychology because he felt that the organization should develop an intellectual movement without a leader.


title: Abraham Maslow

text: While jogging, Maslow had a severe heart attack and died on June 8, 1970, at the age of 62 in Menlo Park, California. He is buried at Mount Auburn Cemetery.


title: Abraham Maslow

text: Most psychologists before him had been concerned with the abnormal and the ill. He urged people to acknowledge their basic needs before addressing higher needs and ultimately self-actualization. He wanted to know what constituted positive mental health. Humanistic psychology gave rise to several different therapies, all guided by the idea that people possess the inner resources for growth and healing and that the point of therapy is to help remove obstacles to individuals' achieving them. The most famous of these was client-centered therapy developed by Carl Rogers.


title: Abraham Maslow

text: Humanistic psychology theory suits people who see the positive side of humanity and believe in free will. This theory clearly contrasts with Freud's theory of biological determinism. Another significant strength is that humanistic psychology theory is compatible with other schools of thought. Maslow's Hierarchy is also applicable to other topics, such as finance, economics, or even in history or criminology. Humanist psychology, also coined "positive psychology", is criticized for its lack of empirical validation and therefore its lack of usefulness in treating specific problems. It may also fail to help or diagnose people who have severe mental disorders. Humanistic psychologists believe that every person has a strong desire to realize their full potential, to reach a level of "self-actualization". The main point of that new movement, that reached its peak in 1960s, was to emphasize the positive potential of human beings. Maslow positioned his work as a vital complement to that of Freud:


title: Abraham Maslow

text: However, Maslow was highly critical of Freud, since humanistic psychologists did not recognize spirituality as a navigation for our behaviours.


title: Abraham Maslow

text: To prove that humans are not blindly reacting to situations, but trying to accomplish something greater, Maslow studied mentally healthy individuals instead of people with serious psychological issues. He focused on self-actualizing people. Self-actualizing people indicate a "coherent personality syndrome" and represent optimal psychological health and functioning.


title: Abraham Maslow

text: This informed his theory that a person enjoys "peak experiences", high points in life when the individual is in harmony with himself and his surroundings. In Maslow's view, self-actualized people can have many peak experiences throughout a day while others have those experiences less frequently. He believed that psychedelic drugs like LSD and Psilocybin can produce peak experiences in the right people under the right circumstances.


title: Abraham Maslow

text: Beyond the routine of needs fulfillment, Maslow envisioned moments of extraordinary experience, known as Peak experiences, which are profound moments of love, understanding, happiness, or rapture, during which a person feels more whole, alive, self-sufficient and yet a part of the world, more aware of truth, justice, harmony, goodness, and so on. Self-actualizing people are more likely to have peak experiences. In other words, these "peak experiences" or states of flow are the reflections of the realization of one's human potential and represent the height of personality development.


title: Abraham Maslow

text: In later writings, Maslow moved to a more inclusive model that allowed for, in addition to intense peak experiences, longer-lasting periods of serene Being-cognition that he termed "plateau experiences". He borrowed this term from the Indian scientist and yoga practitioner, U. A. Asrani, with whom he corresponded. Maslow stated that the shift from the peak to the plateau experience is related to the natural aging process, in which an individual has a shift in life values about what is actually important in one's life and what is not important. In spite of the personal significance with the plateau experience, Maslow was not able to conduct a comprehensive study of this phenomenon due to health problems that developed toward the end of his life.


title: Abraham Maslow

text: In studying accounts of peak experiences, Maslow identified a manner of thought he called "Being-cognition" (or "B-cognition"), which is holistic and accepting, as opposed to the evaluative "Deficiency-cognition" (or "D-cognition"), and values he called "Being-values". He listed the B-values as:


title: Abraham Maslow

text: Maslow described human needs as ordered in a prepotent hierarchy—a pressing need would need to be mostly satisfied before someone would give their attention to the next highest need. None of his published works included a visual representation of the hierarchy. The pyramidal diagram illustrating the Maslow needs hierarchy may have been created by a psychology textbook publisher as an illustrative device. This now iconic pyramid frequently depicts the spectrum of human needs, both physical and psychological, as accompaniment to articles describing Maslow's needs theory and may give the impression that the Hierarchy of Needs is a fixed and rigid sequence of progression. Yet, starting with the first publication of his theory in 1943, Maslow described human needs as being relatively fluid—with many needs being present in a person simultaneously.


title: Abraham Maslow

text: The hierarchy of human needs model suggests that human needs will only be fulfilled one level at a time.


title: Abraham Maslow

text: According to Maslow's theory, when a human being ascends the levels of the hierarchy having fulfilled the needs in the hierarchy, one may eventually achieve self-actualization. Late in life, Maslow came to conclude that self-actualization was not an automatic outcome of satisfying the other human needs.


title: Abraham Maslow

text: The first four levels are known as "Deficit needs" or "D-needs". This means that if you do not have enough of one of those four needs, you will have the feeling that you need to get it. But when you do get them, then you feel content. These needs alone are not motivating.


title: Abraham Maslow

text: Maslow wrote that there are certain conditions that must be fulfilled in order for the basic needs to be satisfied. For example, freedom of speech, freedom to express oneself, and freedom to seek new information are a few of the prerequisites. Any blockages of these freedoms could prevent the satisfaction of the basic needs.


title: Abraham Maslow

text: Maslow's Hierarchy is used in higher education for advising students and student retention as well as a key concept in student development. Maslow's Hierarchy has been subject to internet memes over the past few years, specifically looking at the modern integration of technology in our lives and humorously suggesting that Wi-Fi was among the most basic of human needs.


title: Abraham Maslow

text: Maslow defined Self-actualization as achieving the fullest use of one's talents and interests—the need "to become everything that one is capable of becoming." As implied by its name, self-actualization is highly individualistic and reflects Maslow's premise that the self is "sovereign and inviolable" and entitled to "his or her own tastes, opinions, values, etc." Indeed, some have characterized self-actualization as "healthy narcissism."


title: Abraham Maslow

text: Maslow realized that the self-actualizing individuals he studied had similar personality traits. Maslow selected individuals based on his subjective view of them as self-actualized people. Some of the people he studied included Thomas Jefferson, Abraham Lincoln, and Eleanor Roosevelt. In his daily journal (1961–63) Maslow wrote: "Eupsychia club, heroes that I write for, my judges, the ones I want to please: Jefferson, Spinoza, Socrates, Aristotle, James, Bergson, Norman Thomas, Upton Sinclair (both heroes of my youth)." All were "reality centered," able to differentiate what was fraudulent from what was genuine. They were also "problem centered," meaning that they treated life's difficulties as problems that demanded solutions. These individuals also were comfortable being alone and had healthy personal relationships. They had only a few close friends and family rather than a large number of shallow relationships.


title: Abraham Maslow

text: Self-actualizing people tend to focus on problems outside themselves; have a clear sense of what is true and what is false; are spontaneous and creative; and are not bound too strictly by social conventions.


title: Abraham Maslow

text: Maslow noticed that self-actualized individuals had a better insight of reality, deeply accepted themselves, others and the world, and also had faced many problems and were known to be impulsive people. These self-actualized individuals were very independent and private when it came to their environment and culture, especially their very own individual development on "potentialities and inner resources".


title: Abraham Maslow

text: Maslow based his theory partially on his own assumptions about human potential and partially on his case studies of historical figures whom he believed to be self-actualized, including Albert Einstein and Henry David Thoreau. Consequently, Maslow argued, the way in which essential needs are fulfilled is just as important as the needs themselves. Together, these define the human experience. To the extent a person finds cooperative social fulfillment, he establishes meaningful relationships with other people and the larger world. In other words, he establishes meaningful connections to an external reality—an essential component of self-actualization. In contrast, to the extent that vital needs find selfish and competitive fulfillment, a person acquires hostile emotions and limited external relationships—his awareness remains internal and limited.


title: Abraham Maslow

text: Maslow used the term metamotivation to describe self-actualized people who are driven by innate forces beyond their basic needs, so that they may explore and reach their full human potential. Maslow's theory of motivation gave insight on individuals having the ability to be motivated by a calling, mission or life purpose. It is noted that metamotivation may also be connected to what Maslow called B-(being) creativity, which is a creativity that comes from being motivated by a higher stage of growth. Another type of creativity that was described by Maslow is known as D-(deficiency) creativity, which suggests that creativity results from an individual's need to fill a gap that is left by an unsatisfied primary need or the need for assurance and acceptance.


title: Abraham Maslow

text: Maslow based his study on the writings of other psychologists, Albert Einstein, and people he knew who [he felt] clearly met the standard of self-actualization.


title: Abraham Maslow

text: Maslow used Einstein's writings and accomplishments to exemplify the characteristics of the self-actualized person. Ruth Benedict and Max Wertheimer work was also very influential to Maslow's models of self-actualization. In this case, from a quantative-sciences perspective there are numerous problems with this particular approach, which has caused much criticism. First, it could be argued that biographical analysis as a method is extremely subjective as it is based entirely on the opinion of the researcher. Personal opinion is always prone to bias, which reduces the validity of any data obtained. Therefore, Maslow's operational definition of Self-actualization must not be uncritically accepted as quantitative fact.


title: Abraham Maslow

text: During the 1960s Maslow founded with Stanislav Grof, Viktor Frankl, James Fadiman, Anthony Sutich, Miles Vich and Michael Murphy, the school of transpersonal psychology. Maslow had concluded that humanistic psychology was incapable of explaining all aspects of human experience. He identified various mystical, ecstatic, or spiritual states known as "peak experiences" as experiences beyond self-actualization. Maslow called these experiences "a fourth force in psychology", which he named transpersonal psychology. Transpersonal psychology was concerned with the "empirical, scientific study of, and responsible implementation of the finding relevant to, becoming, mystical, ecstatic, and spiritual states" (Olson & Hergenhahn, 2011).


title: Abraham Maslow

text: In 1962 Maslow published a collection of papers on this theme, which developed into his 1968 book "Toward a Psychology of Being". In this book Maslow stresses the importance of transpersonal psychology to human beings, writing: "without the transpersonal, we get sick, violent, and nihilistic, or else hopeless and apathetic" (Olson & Hergenhahn, 2011). Human beings, he came to believe, need something bigger than themselves that they are connected to in a naturalistic sense, but not in a religious sense: Maslow himself was an atheist and found it difficult to accept religious experience as valid unless placed in a positivistic framework. In fact, Maslow's position on God and religion was quite complex. While he rejected organized religion and its beliefs, he wrote extensively on the human being's need for the sacred and spoke of God in more philosophical terms, as beauty, truth and goodness, or as a force or a principle.


title: Abraham Maslow

text: Awareness of transpersonal psychology became widespread within psychology, and the "Journal of Transpersonal Psychology" was founded in 1969, a year after Abraham Maslow became the president of the American Psychological Association. In the United States, transpersonal psychology encouraged recognition for non-western psychologies, philosophies, and religions, and promoted understanding of "higher states of consciousness", for instance through intense meditation. Transpersonal psychology has been applied in many areas, including transpersonal business studies.


title: Abraham Maslow

text: Maslow called his work positive psychology. Since 1968 his work has influenced the development of Positive Psychotherapy, a transcultural, humanistic based psychodynamic psychotherapy method used in mental health and psychosomatic treatment founded by Nossrat Peseschkian. Since 1999 Maslow's work enjoyed a revival of interest and influence among leaders of the positive psychology movement such as Martin Seligman. This movement focuses only on a higher human nature.


title: Abraham Maslow

text: Positive psychology spends its research looking at the positive side of things and how they go right rather than the pessimistic side.


title: Abraham Maslow

text: In 1966, Maslow published a pioneering work in the psychology of science, "The Psychology of Science: A Reconnaissance", the first book ever actually titled 'psychology of science'. In this book Maslow proposed a model of 'characterologically relative' science, which he characterized as an ardent opposition to the "historically, philosophically, sociologically and psychologically naıve" positivistic reluctance to see science "relative to time, place, and local culture". As Maslow acknowledged, the book was greatly inspired by Thomas Kuhn's "The Structure of Scientific Revolutions" (1962), and it offers a psychological reading of Kuhn's famous distinction between "normal" and "revolutionary" science in the context of his own distinction between "safety" and "growth" science, put forward as part of a larger program for the psychology of science, outlined already in his 1954 "magnum opus" "Motivation and Personality". Not only that Maslow offered a psychological reading of Kuhn's categories of "normal" and "revolutionary" science as an aftermath of Kuhn's "Structure", but he also offered a strikingly similar dichotomous structure of science 16 years before the first edition of "Structure", in his nowadays little known 1946 paper "Means-Centering Versus Problem-Centering in Science" published in the journal "Philosophy of Science".


title: Abraham Maslow

text: Abraham Maslow is also known for Maslow's hammer, popularly phrased as "if all you have is a hammer, everything looks like a nail" from his book "The Psychology of Science", published in 1966.


title: Abraham Maslow

text: Maslow's ideas have been criticized for their lack of scientific rigor. He was criticized as too soft scientifically by American empiricists. In 2006, author and former philosophy professor Christina Hoff Sommers and practicing psychiatrist Sally Satel asserted that, due to lack of empirical support, Maslow's ideas have fallen out of fashion and are "no longer taken seriously in the world of academic psychology."


title: Abraham Maslow

text: Positive psychology spends much of its research looking for how things go right rather than the more pessimistic view point, how things go wrong.


title: Abraham Maslow

text: Furthermore, the Hierarchy of Needs has been accused of having a cultural bias—mainly reflecting Western values and ideologies. From the perspective of many cultural psychologists, this concept is considered relative to each culture and society and cannot be universally applied. However, according to the University of Illinois researchers Ed Diener and Louis Tay, who put Maslow's ideas to the test with data collected from 60,865 participants in 123 countries around the world over the period of five years (2005-2010), Maslow was essentially right in that there are universal human needs regardless of cultural differences, although the authors claim to have found certain departures from the order of their fulfillment Maslow described. In particular, while they found—clearly in accordance with Maslow—that people tend to achieve basic and safety needs before other needs, as well as that other "higher needs" tend to be fulfilled in a certain order, the order in which they are fulfilled apparently does not strongly influence their subjective well-being (SWB). As put by the authors of the study, humans thus


title: Abraham Maslow

text: Maslow, however, would not be surprised by these findings, since he clearly and repeatedly emphasized that the need hierarchy is not a rigid fixed order as it is often presented:


title: Abraham Maslow

text: Maslow also regarded that the relationship between different human needs and behaviour, being in fact often motivated simultaneously by multiple needs, is not a one-to-one correspondence, i.e., that "these needs must be understood not to be exclusive or single determiners of certain kinds of behavior".


title: Abraham Maslow

text: Maslow's concept of self-actualizing people was united with Piaget’s developmental theory to the process of initiation in 1993. Maslow's theory of self-actualization has been met with significant resistance. The theory itself is crucial to the humanistic branch of psychology and yet it is widely misunderstood. The concept behind self-actualization is widely misunderstood and subject to frequent scrutiny.


title: Abraham Maslow

text: Maslow was criticized for noting too many exceptions to his theory. As he acknowledged these exceptions, he did not do much to account for them. Shortly prior to his death, one problem he tried to resolve was that there are people who have satisfied their deficiency needs but still do not become self-actualized. He never resolved this inconsistency within his theory.


title: Abraham Maslow

text: Social psychologist David Myers has pointed out Maslow's selection bias, rooted in the choice to study individuals who lived out his own values. If he had studied other historical heroes, such as Napoleon, Alexander the Great, and John D. Rockefeller, his descriptions of self-actualization might have been significantly different.


title: Abraham Maslow

text: Later in life, Maslow was concerned with questions such as, "Why don't more people self-actualize if their basic needs are met?


title: Abraham Maslow

text: In the spring of 1961, Maslow and Tony Sutich founded the "Journal of Humanistic Psychology", with Miles Vich as editor until 1971. The journal printed its first issue in early 1961 and continues to publish academic papers.


title: Abraham Maslow

text: Maslow attended the Association for Humanistic Psychology's founding meeting in 1963 where he declined nomination as its president, arguing that the new organization should develop an intellectual movement without a leader which resulted in useful strategy during the field's early years.


title: Resonance

text: Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillating force is applied at a resonant frequency of a dynamic system, the system will oscillate at a higher amplitude than when the same force is applied at other, non-resonant frequencies.


title: Resonance

text: Frequencies at which the response amplitude is a relative maximum are also known as resonant frequencies or resonance frequencies of the system. Small periodic forces that are near a resonant frequency of the system have the ability to produce large amplitude oscillations in the system due to the storage of vibrational energy.


title: Resonance

text: Resonance phenomena occur with all types of vibrations or waves: there is mechanical resonance, orbital resonance, acoustic resonance, electromagnetic resonance, nuclear magnetic resonance (NMR), electron spin resonance (ESR) and resonance of quantum wave functions. Resonant systems can be used to generate vibrations of a specific frequency (e.g., musical instruments), or pick out specific frequencies from a complex vibration containing many frequencies (e.g., filters).


title: Resonance

text: The term "resonance" (from Latin "resonantia", 'echo', from "resonare", 'resound') originated from the field of acoustics, particularly the sympathetic resonance observed in musical instruments, e.g., when one string starts to vibrate and produce sound after a different one is struck.


title: Resonance

text: Resonance occurs when a system is able to store and easily transfer energy between two or more different storage modes (such as kinetic energy and potential energy in the case of a simple pendulum). However, there are some losses from cycle to cycle, called damping. When damping is small, the resonant frequency is approximately equal to the natural frequency of the system, which is a frequency of unforced vibrations. Some systems have multiple, distinct, resonant frequencies.


title: Resonance

text: A familiar example is a playground swing, which acts as a pendulum. Pushing a person in a swing in time with the natural interval of the swing (its resonant frequency) makes the swing go higher and higher (maximum amplitude), while attempts to push the swing at a faster or slower tempo produce smaller arcs. This is because the energy the swing absorbs is maximized when the pushes match the swing's natural oscillations.


title: Resonance

text: Resonance occurs widely in nature, and is exploited in many devices. It is the mechanism by which virtually all sinusoidal waves and vibrations are generated. Many sounds we hear, such as when hard objects of metal, glass, or wood are struck, are caused by brief resonant vibrations in the object. Light and other short wavelength electromagnetic radiation is produced by resonance on an atomic scale, such as electrons in atoms. Other examples of resonance:


title: Resonance

text: Resonance manifests itself in many linear and nonlinear systems as oscillations around an equilibrium point. When the system is driven by a sinusoidal external input, a measured output of the system may oscillate in response. The ratio of the amplitude of the output's steady-state oscillations to the input's oscillations is called the gain, and the gain can be a function of the frequency of the sinusoidal external input. Peaks in the gain at certain frequencies correspond to resonances, where the amplitude of the measured output's oscillations are disproportionately large.


title: Resonance

text: Since many linear and nonlinear systems that oscillate are modeled as harmonic oscillators near their equilibria, this section begins with a derivation of the resonant frequency for a driven, damped harmonic oscillator. The section then uses an RLC circuit to illustrate connections between resonance and a system's transfer function, frequency response, poles, and zeroes. Building off the RLC circuit example, the section then generalizes these relationships for higher-order linear systems with multiple inputs and outputs.


title: Resonance

text: Consider a damped mass on a spring driven by a sinusoidal, externally applied force. Newton's second law takes the form


title: Resonance

text: where "m" is the mass, "x" is the displacement of the mass from the equilibrium point, "F" is the driving amplitude, "ω" is the driving angular frequency, "k" is the spring constant, and "c" is the viscous damping coefficient. This can be rewritten in the form


title: Resonance

text: Many sources also refer to "ω" as the "resonant frequency". However, as shown below, when analyzing oscillations of the displacement "x"("t"), the resonant frequency is close to but not the same as "ω". In general the resonant frequency is close to but not necessarily the same as the natural frequency. The RLC circuit example in the next section gives examples of different resonant frequencies for the same system.


title: Resonance

text: The general solution of Equation () is the sum of a transient solution that depends on initial conditions and a steady state solution that is independent of initial conditions and depends only on the driving amplitude "F", driving frequency "ω", undamped angular frequency "ω", and the damping ratio "ζ". The transient solution decays in a relatively short amount of time, so to study resonance it is sufficient to consider the steady state solution.


title: Resonance

text: It is possible to write the steady-state solution for "x"("t") as a function proportional to the driving force with an induced phase change "φ",


title: Resonance

text: The phase value is usually taken to be between −180° and 0 so it represents a phase lag for both positive and negative values of the arctan argument.


title: Resonance

text: Resonance occurs when, at certain driving frequencies, the steady-state amplitude of "x"("t") is large compared to its amplitude at other driving frequencies. For the mass on a spring, resonance corresponds physically to the mass's oscillations having large displacements from the spring's equilibrium position at certain driving frequencies. Looking at the amplitude of "x"("t") as a function of the driving frequency "ω", the amplitude is maximal at the driving frequency


title: Resonance

text: "ω" is the resonant frequency for this system. Again, note that the resonant frequency does not equal the undamped angular frequency "ω" of the oscillator. They are proportional, and if the damping ratio goes to zero they are the same, but for non-zero damping they are not the same frequency. As shown in the figure, resonance may also occur at other frequencies near the resonant frequency, including "ω", but the maximum response is at the resonant frequency.


title: Resonance

text: Also note that "ω" is only real and non-zero if formula_5, so this system can only resonate when the harmonic oscillator is significantly underdamped. For systems with a very small damping ratio and a driving frequency near the resonant frequency, the steady state oscillations can become very large.


title: Resonance

text: For other driven, damped harmonic oscillators whose equations of motion do not look exactly like the mass on a spring example, the resonant frequency remains


title: Resonance

text: but the definitions of "ω" and "ζ" change based on the physics of the system. For a pendulum of length "ℓ" and small displacement angle "θ", Equation () becomes


title: Resonance

text: Consider a circuit consisting of a resistor with resistance "R", an inductor with inductance "L", and a capacitor with capacitance "C" connected in series with current "i"("t") and driven by a voltage source with voltage "v"("t"). The voltage drop around the circuit is


title: Resonance

text: Rather than analyzing a candidate solution to this equation like in the mass on a spring example above, this section will analyze the frequency response of this circuit. Taking the Laplace transform of Equation (),


title: Resonance

text: where "I"("s") and "V"("s") are the Laplace transform of the current and input voltage, respectively, and "s" is a complex frequency parameter in the Laplace domain. Rearranging terms,


title: Resonance

text: An RLC circuit in series presents several options for where to measure an output voltage. Suppose the output voltage of interest is the voltage drop across the capacitor. As shown above, in the Laplace domain this voltage is


title: Resonance

text: "H"("s") is the transfer function between the input voltage and the output voltage. Note that this transfer function has two poles–roots of the polynomial in the transfer function's denominator–at


title: Resonance

text: and no zeros–roots of the polynomial in the transfer function's numerator. Moreover, note that for , the magnitude of these poles is the natural frequency "ω" and that for , our condition for resonance in the harmonic oscillator example, the poles are closer to the imaginary axis than to the real axis.


title: Resonance

text: Evaluating "H"("s") along the imaginary axis , the transfer function describes the frequency response of this circuit. Equivalently, the frequency response can be analyzed by taking the Fourier transform of Equation () instead of the Laplace transform. The transfer function, which is also complex, can be written as a gain and phase,


title: Resonance

text: A sinusoidal input voltage at frequency "ω" results in an output voltage at the same frequency that has been scaled by "G"("ω") and has a phase shift "Φ"("ω"). The gain and phase can be plotted versus frequency on a Bode plot. For the RLC circuit's capacitor voltage, the gain of the transfer function "H"("iω") is


title: Resonance

text: Note the similarity between the gain here and the amplitude in Equation (). Once again, the gain is maximized at the resonant frequency


title: Resonance

text: Here, the resonance corresponds physically to having a relatively large amplitude for the steady state oscillations of the voltage across the capacitor compared to its amplitude at other driving frequencies.


title: Resonance

text: The resonant frequency need not always take the form given in the examples above. For the RLC circuit, suppose instead that the output voltage of interest is the voltage across the inductor. As shown above, in the Laplace domain the voltage across the inductor is


title: Resonance

text: using the same definitions for "ω" and "ζ" as in the previous example. The transfer function between "V"("s") and this new "V"("s") across the inductor is


title: Resonance

text: Note that this transfer function has the same poles as the transfer function in the previous example, but it also has two zeroes in the numerator at . Evaluating "H"("s") along the imaginary axis, its gain becomes


title: Resonance

text: Compared to the gain in Equation () using the capacitor voltage as the output, this gain has a factor of "ω" in the numerator and will therefore have a different resonant frequency that maximizes the gain. That frequency is


title: Resonance

text: So for the same RLC circuit but with the voltage across the inductor as the output, the resonant frequency is now "larger" than the natural frequency, though it still tends towards the natural frequency as the damping ratio goes to zero. That the same circuit can have different resonant frequencies for different choices of output is not contradictory. As shown in Equation (), the voltage drop across the circuit is divided among the three circuit elements, and each element has different dynamics. The capacitor's voltage grows slowly by integrating the current over time and is therefore more sensitive to lower frequencies, whereas the inductor's voltage grows when the current changes rapidly and is therefore more sensitive to higher frequencies. While the circuit as a whole has a natural frequency where it tends to oscillate, the different dynamics of each circuit element make each element resonate at a slightly different frequency.


title: Resonance

text: Suppose that the output voltage of interest is the voltage across the resistor. In the Laplace domain the voltage across the resistor is


title: Resonance

text: and using the same natural frequency and damping ratio as in the capacitor example the transfer function is


title: Resonance

text: Note that this transfer function also has the same poles as the previous RLC circuit examples, but it only has one zero in the numerator at "s" = 0. For this transfer function, its gain is


title: Resonance

text: and the gain is one at this frequency, so the voltage across the resistor resonates "at" the circuit's natural frequency and at this frequency the amplitude of the voltage across the resistor equals the input voltage's amplitude.


title: Resonance

text: Some systems exhibit antiresonance that can be analyzed in the same way as resonance. For antiresonance, the amplitude of the response of the system at certain frequencies is disproportionately "small" rather than being disproportionately large. In the RLC circuit example, this phenomenon can be observed by analyzing both the inductor and the capacitor combined.


title: Resonance

text: Suppose that the output voltage of interest in the RLC circuit is the voltage across the inductor "and" the capacitor combined in series. Equation () showed that the sum of the voltages across the three circuit elements sums to the input voltage, so measuring the output voltage as the sum of the inductor and capacitor voltages combined is the same as "v" minus the voltage drop across the resistor. The previous example showed that at the natural frequency of the system, the amplitude of the voltage drop across the resistor "equals" the amplitude of "v", and therefore the voltage across the inductor and capacitor combined has zero amplitude. We can show this with the transfer function.


title: Resonance

text: Using the same natural frequency and damping ratios as the previous examples, the transfer function is


title: Resonance

text: Rather than look for resonance, i.e., peaks of the gain, notice that the gain goes to zero at "ω" = "ω", which complements our analysis of the resistor's voltage. This is called antiresonance, which has the opposite effect of resonance. Rather than result in outputs that are disproportionately large at this frequency, this circuit with this choice of output has no response at all at this frequency. The frequency that is filtered out corresponds exactly to the zeroes of the transfer function, which were shown in Equation () and were on the imaginary axis.


title: Resonance

text: These RLC circuit examples illustrate how resonance is related to the frequency response of the system. Specifically, these examples illustrate:


title: Resonance

text: Next consider an arbitrary linear system with multiple inputs and outputs. For example, in state-space representation a third order linear time-invariant system with three inputs and two outputs might be written as


title: Resonance

text: where "u"("t") are the inputs, "x"(t) are the state variables, "y"("t") are the outputs, and "A", "B", "C", and "D" are matrices describing the dynamics between the variables.


title: Resonance

text: This system has a transfer function matrix whose elements are the transfer functions between the various inputs and outputs. For example,


title: Resonance

text: Each "H"("s") is a scalar transfer function linking one of the inputs to one of the outputs. The RLC circuit examples above had one input voltage and showed four possible output voltages–across the capacitor, across the inductor, across the resistor, and across the capacitor and inductor combined in series–each with its own transfer function. If the RLC circuit were set up to measure all four of these output voltages, that system would have a 4×1 transfer function matrix linking the single input to each of the four outputs.


title: Resonance

text: Peaks in the gain at certain frequencies correspond to resonances between that transfer function's input and output, assuming the system is stable.


title: Resonance

text: Each transfer function "H"("s") can also be written as a fraction whose numerator and denominator are polynomials of "s".


title: Resonance

text: The complex roots of the numerator are called zeroes, and the complex roots of the denominator are called poles. For a stable system, the positions of these poles and zeroes on the complex plane give some indication of whether the system can resonate or antiresonate and at which frequencies. In particular, any stable or marginally stable, complex conjugate pair of poles with imaginary components can be written in terms of a natural frequency and a damping ratio as


title: Resonance

text: as in Equation (). The natural frequency "ω" of that pole is the magnitude of the position of the pole on the complex plane and the damping ratio of that pole determines how quickly that oscillation decays. In general,


title: Resonance

text: In the RLC circuit example, the first generalization relating poles to resonance is observed in Equation (). The second generalization relating zeroes to antiresonance is observed in Equation (). In the examples of the harmonic oscillator, the RLC circuit capacitor voltage, and the RLC circuit inductor voltage, "poles near the imaginary axis" corresponds to the significantly underdamped condition ζ < 1/formula_40.


title: Resonance

text: A physical system can have as many natural frequencies as it has degrees of freedom and can resonate near each of those natural frequencies. A mass on a spring, which has one degree of freedom, has one natural frequency. A double pendulum, which has two degrees of freedom, can have two natural frequencies. As the number of coupled harmonic oscillators increases, the time it takes to transfer energy from one to the next becomes significant. Systems with very large numbers of degrees of freedom can be thought of as continuous rather than as having discrete oscillators.


title: Resonance

text: Energy transfers from one oscillator to the next in the form of waves. For example, the string of a guitar or the surface of water in a bowl can be modeled as a continuum of small coupled oscillators and waves can travel along them. In many cases these systems have the potential to resonate at certain frequencies, forming standing waves with large-amplitude oscillations at fixed positions. Resonance in the form of standing waves underlies many familiar phenomena, such as the sound produced by musical instruments, electromagnetic cavities used in lasers and microwave ovens, and energy levels of atoms.


title: Resonance

text: When a string of fixed length is driven at a particular frequency, a wave propagates along the string at the same frequency. The waves reflect off the ends of the string, and eventually a steady state is reached with waves traveling in both directions. The waveform is the superposition of the waves.


title: Resonance

text: At certain frequencies, the steady state waveform does not appear to travel along the string. At fixed positions called nodes, the string is never displaced. Between the nodes the string oscillates and exactly halfway between the nodes–at positions called anti-nodes–the oscillations have their largest amplitude.


title: Resonance

text: For a string of length formula_41 with fixed ends, the displacement formula_42 of the string perpendicular to the formula_43-axis at time formula_44 is


title: Resonance

text: where formula_51 is the speed of the wave and the integer formula_52 denotes different modes or harmonics. The standing wave with oscillates at the fundamental frequency and has a wavelength that is twice the length of the string. The possible modes of oscillation form a harmonic series.


title: Resonance

text: Mechanical resonance is the tendency of a mechanical system to absorb more energy when the frequency of its oscillations matches the system's natural frequency of vibration than it does at other frequencies. It may cause violent swaying motions and even catastrophic failure in improperly constructed structures including bridges, buildings, trains, and aircraft. When designing objects, engineers must ensure the mechanical resonance frequencies of the component parts do not match driving vibrational frequencies of motors or other oscillating parts, a phenomenon known as resonance disaster.


title: Resonance

text: Avoiding resonance disasters is a major concern in every building, tower, and bridge construction project. As a countermeasure, shock mounts can be installed to absorb resonant frequencies and thus dissipate the absorbed energy. The Taipei 101 building relies on a —a tuned mass damper—to cancel resonance. Furthermore, the structure is designed to resonate at a frequency that does not typically occur. Buildings in seismic zones are often constructed to take into account the oscillating frequencies of expected ground motion. In addition, engineers designing objects having engines must ensure that the mechanical resonant frequencies of the component parts do not match driving vibrational frequencies of the motors or other strongly oscillating parts.


title: Resonance

text: The cadence of runners has been hypothesized to be energetically favorable due to resonance between the elastic energy stored in the lower limb and the mass of the runner.


title: Resonance

text: Acoustic resonance is a branch of mechanical resonance that is concerned with the mechanical vibrations across the frequency range of human hearing, in other words sound. For humans, hearing is normally limited to frequencies between about 20 Hz and 20,000 Hz (20 kHz), Many objects and materials act as resonators with resonant frequencies within this range, and when struck vibrate mechanically, pushing on the surrounding air to create sound waves. This is the source of many percussive sounds we hear.


title: Resonance

text: Acoustic resonance is an important consideration for instrument builders, as most acoustic instruments use resonators, such as the strings and body of a violin, the length of tube in a flute, and the shape of, and tension on, a drum membrane.