title: War Machine

text: After the events of the "Time War" storyline, in which Rhodes teamed up with Captain America, Bucky and Sgt. Nick Fury & his Howling Commandos to stop Neo-Nazis from sending modern weaponry to Nazi Germany, the War Machine armor was lost in the time stream. Rhodes returned to civilian life, but he ended up acquiring a brand new alien armor known as the Eidolon Warwear after meeting a mysterious woman named Skye and fighting an alien known as a Lictor. Skye was sent to teach Rhodes to use the Warwear and revealed that Rhodes was chosen to fight against Stark (who was under the control of Immortus disguised as Kang the Conqueror). Skye was fatally wounded by Dirge, another Eidolon Warrior sent by Immortus, and Rhodes defeated him in combat. Stark eventually breaks free of Immortus' control and sacrificed his life while Rhodes foiled Immortus' plot by using Dirge's Warwear to destroy the Starcore satellite armed with a chronographic weapon. S.H.I.E.L.D. was made aware of down, but Rhodes evaded capture. To protect Worldwatch, he resigns as executive director.


title: War Machine

text: In "Tales of the Marvel Universe", Rhodes rejoined Stark Enterprises to protect his friend's legacy while the Japanese company Fujikawa Industries bought out Stark Enterprises. Rhodes was kept around to help with the transition to Stark-Fujikawa. He was offered the job of President Of Corporate Liaison Operations, but kept away from Fujikawa's attempt to discover the secrets to Stark's Iron Man armor technology contained in a single gauntlet. Rhodes infiltrated the security system at Stark-Fujikawa's Research and Development facility, recovered the gauntlet, and purged the Fujikawa database of all Iron Man armor technology data by downloading the Eidolon Warwear directly into the Fujikawa computers to attack the system. Losing the armor as a result of the sabotage mission, Rhodes quits Stark-Fujikawa. After serving as one of Stark's trustees when Iron Man was presumed dead after the final battle with Onslaught, Rhodes starts his own marine salvage business called "Rhodes Recovery" and retires from superheroics.


title: War Machine

text: Despite staying in retirement and focusing on his salvaging company, Rhodes assisted Stark on occasion. In volume three of "Iron Man", he helped Stark defeat freelance mercenary and arms dealer Parnell Jacobs, who was masquerading as a villainous War Machine. A former friend and mercenary partner of Rhodes, Jacobs was under the employ of Sunset Bain and piloted a version of the War Machine armor based on armor parts that Jacobs found from the discarded original and reverse engineering by Stuart Clarke.


title: War Machine

text: Due to mismanagement by his accountant and an extravagant lifestyle, Rhodes is left with depleted funds and files for bankruptcy. He is informed by the New York Police Department that his sister Jeanette "Star" Rhodes was killed in a notorious section of Brooklyn overridden with crime and drugs known as "Little Mogadishu". During a fight with some local thugs, he is helped by Josiah el Hajj Saddiq a.k.a. Josiah X, a local minister who is the son of the black Captain America. Josiah X helped Rhodes obtain footage of Jeanette's killers. With the police unable to apprehend, Rhodes captured his sister's murderers with NYPD narcotics officer Kevin "Kasper" Cole making the arrests. He discovers that the criminals that killed Jeanette were drug dealers working for the 66 Bridges, a powerful street gang with a big percentage of East Coast criminal operations. Rhodes unknowingly invested in the 66's front company Grace & Tumbalt, a black-owned corporation that created Little Mogadishu due to their gentrification efforts. During his campaign against the 66 Bridges, Rhodes crosses paths with Cole, who secretly fights crime as The White Tiger in order to gain arrests for a promotion to detective, and Danny Vincent (Manuel Vincente), an ex-spy known as Junta with allegiance only to himself. Joining forces with these two men along with Josiah X as Justice, Rhodes and The Crew took on the 66 Bridges gang and their CEO Nigel "Triage" Blacque.


title: War Machine

text: Rhodes later becomes a key member of the Office of National Emergency (O*N*E) and the head combat instructor for Sentinel Squad O*N*E. He began developing doubts about the nature of his job, such as being ordered to arrest the Black Panther and Storm when they refused to sign SHRA.


title: War Machine

text: When Rhodes served as a military consultant at a base in Dubai, a terrorist attack left Rhodes severely injured. Stark arrived in Dubai and rebuilt him with new limbs, bionics, and cybernetics. Rhodes once again becomes War Machine and was made field commander and a director of Camp Hammond to help train SHRA registered recruits of the Fifty State Initiative program. When the Skrulls invaded Earth and unleashed a virus that disabled all Starktech systems along with Rhodes' life-support systems, he is forced to rely on Baron Von Blitzschlag's electrical powers to keep him alive while managing to activate a cluster of emergency generators in his armor that incorporated Stanetech parts in its design.


title: War Machine

text: In the "War Machine: Weapon Of S.H.I.E.L.D." storyline, Rhodes received a secret holographic message with coordinates after the global Starktech failure. Despite an intercepting Skrull fleet, Rhodes found a secret cloaked satellite in outer space with Suzanne "Suzi" Endo at the satellite ahead of him. Endo was there to help because of her background in cybernetics and Rhodes viewed another message from Stark revealing that Rhodes' armor, as well as the satellite, was independent from all Earth systems with Rhodes himself as a part of Stark's contingency plan. A Skrull fleet followed Rhodes to the satellite and Endo revealed that the satellite is a functional weapon with Rhodes being the key to its activation. With the satellite linked to Rhodes, it transformed into a giant "War Machine" robotic form. Destroying the Skrull fleet, he left the satellite to Russian airspace to destroy an escaping Skull ship. He made his way to a weapons depot in Tatischevo where the Winter Guard was protecting the nuclear weapons from the Skrulls. The Winter Guard ordered him to leave under the orders of the Russian military, but Rhodes ignored it and was captured on a Skrull warship. He escaped, and, with Endo's help, used the warship to destroy the Skrull fleet with the Winter Guard disobeying orders so that they could aid Rhodes. The last Super-Skrull attempted to detonate the nuclear warheads by turning himself into energy, but Rhodes used his armor's capabilities to absorb the energy.


title: War Machine

text: In "Dark Reign: New Nation", Rhodes faced Anton Aubuisson, a corrupt former French soldier with the Roxxon Energy Corporation in negotiations with the Anunquit tribe in western Canada. Rhodes defeated Aubuisson and discovered the use of Ultimo technology given to Aubuisson by Eaglestar International, a corrupt paramilitary defense contracting firm. This led to Rhodes traveling to Santo Marco and finding Parnell Jacobs, once believed to be killed by Stuart Clarke. Rhodes recruits Jacobs to be his "one-man pit crew" to stop Eaglestar's efforts after informing him that Jacobs' estranged wife Dr. Glenda Sandoval, a medic with Eaglestar, was in forced imprisonment. In a side story, a team under the direction of Bethany Cabe developed a clone body for Rhodes to take over. The team's facility was attacked and the clone body was taken by Norman Osborn. Rhodes, with support from Jacobs and Cabe, invades the Eaglestar headquarters in the nation of Aqiria. Rescuing Sandoval and dealing with threats such as the Dark Avenger Ares and civilians infected with Ultimo technology, Rhodes deduced that the Ultimo technology came from the United States where Ultimo was last seen. Rhodes took on the mission of destroying the Ultimo components with Sandoval, Cabe, Jacobs, former S.H.I.E.L.D. agent Jake Oh, and a returning Suzi Endo as "Team War Machine". The team faced the threat of Ultimo in the form of Morgan Stark, Tony Stark's cousin, with the help of Rhodes' former West Coast Avengers teammates and Norman Osborn in a temporary alliance. While Rhodes was captured after ruining Osborn's plan to make Ultimo his weapon, his team exposed the "Bainesville Ten", a group of high-ranking officials and industry captains responsible for worldwide crimes. Despite Osborn's efforts to distract from the indictment of the group by putting Rhodes on trial at The Hague for war crimes, Rhodes and his team foiled Osborn's scheme with Rhodes himself transferred to his clone body after saving the life of a child.


title: War Machine

text: In the "Stark Disassembled" storyline, Rhodes went to Broxton, Oklahoma where Tony Stark was left in a persistent vegetative state. Following recorded instructions from Stark, Rhodes extracted wires from Pepper Potts' Rescue suit and connected Captain America's shield to the implant on Stark's chest, which would be started by Thor's lightning, in order to reboot Stark's brain.


title: War Machine

text: After the "Siege" storyline, War Machine joined the new Secret Avengers team, alongside Beast, Nova, Steve Rogers, Valkyrie, and Moon Knight.


title: War Machine

text: Due to a government contract between Tony Stark's "Stark Resilent" company and The Pentagon, War Machine was assigned a new position as the US military's own "Iron Man". Now at the rank of Lieutenant Colonel, Rhodes is under the command of General Babbage, who has a personal grudge against Rhodes for his actions when he battled Ultimo and Norman Osborn in the previous "War Machine" series. His first assignment was to track down Palmer Addley, a former weapons designer for DARPA, the Defense Advanced Research Projects Agency. Addley is committing terrorist acts around the world, despite having been dead for months. When War Machine confronts the alleged dead man, Addley's response is to drop a nuclear weapon on him. Rhodes survives, but this prompts Tony Stark to replace his armor with a far more advanced model: the "Iron Man 2.0" armor.


title: War Machine

text: During the "Fear Itself" storyline, War Machine is seen in Washington DC helping Ant-Man and Beast. War Machine learns from the Prince of Orphans that the "Eighth City" has been opened.


title: War Machine

text: War Machine then travels to Beijing and assists the Immortal Weapons in closing the portal, but not before having to battle Iron Fist who was unintentionally interfering with their mission by blocking the Immortal Weapon's connection to the city due to having become possessed by Agamotto's power. With Dr. Strange's help, Iron Fist is brought down and the portal is safely closed.


title: War Machine

text: During an attempt by the Mandarin to take down Tony Stark financially and personally, Rhodey fakes his death in a fight with several members of Iron Man's rogue's gallery. Soon after, Tony Stark publicly announces his retirement as Iron Man as a strategy against Mandarin. Following Tony's retirement a new Iron Man has emerged, whose identity is secretly Rhodes. Rhodey remains in the Iron Man armor until the Mandarin is defeated, and it is later mentioned that Stark had confiscated the new Iron Man suit.


title: War Machine

text: With Tony off-world as a member of the new Guardians of the Galaxy, Rhodey is called on by Phil Coulson to consult S.H.I.E.L.D. after a group of Iron Patriot drones are hijacked by A.I.M. Coulson then recruits Rhodes to help stop the rogue Iron Patriot drones. Rhodes communicates with them, and they appear to follow his orders.


title: War Machine

text: Rhodey later appears in a new armor patterned after the Iron Patriot suit. He attempts to apprehend Gambit after the mutant steals one of Tony's old suits of armor, but ends up letting him go after learning that he needed the technology to save the life of one of his friends.


title: War Machine

text: Around this time, Rhodey is caught up in a plot where he is blackmailed by an armored terrorist and forced to assassinate the former president of the United States. With the help of his niece, Lila Rhodes, as well as his father, Rhodey manages to defeat the terrorists and thwart the assassination, but at the cost of his father's life.


title: War Machine

text: Following an eight-month time skip seen in the "Time Runs Out" storyline, Rhodes has returned to using the War Machine armor and is a member of the Avengers. He mentally controls a squad of War Machine drones, which are used to help hunt down the fugitive members of the Illuminati.


title: War Machine

text: As part of Marvel's 2015/2016 All-New, All-Different Marvel branding, War Machine arrives at Stark Tower's Osaka branch to investigate Madame Masque's break-in. After contacting Tony Stark, War Machine leaves Stark Tower's Osaka branch. Then he enters an illegal night club run by Yukio where he asks her about the tech-based ninjas. Yukio states that she cannot say anything if she wants her business to stay afloat. After being threatened with the prospect of having the Avengers storming the place, Yukio points War Machine to a rather big and muscular man in a tuxedo who leaves the nightclub with two ladies entering the car with him. After tossing the car in the air upon grabbing it, War Machine starts to ask the muscular man some questions about the tech-based ninjas only for him to start being attacked by the females with him who are two of those tech-based ninjas as they prepare to attack. War Machine wakes up inside a warehouse where his War Machine armor was deactivated and strapped down. A woman named Tomoe enters the room with several ninjas where she mocks War Machine's presence as a cowardice of Iron Man. She then removes the War Machine armor from James Rhodes and makes it bulkier using the other components in the warehouse as she dons it. While warning James Rhodes that he has walked blindly into their world, Tomoe states that he will also be interrogated.


title: War Machine

text: During the "Civil War II" storyline, War Machine is offered the position of Secretary of Defense by the President of the United States. War Machine assists the Ultimates and the Inhumans in ambushing Thanos at Project Pegasus after the recently emerged Inhuman Ulysses predicted that Thanos would target the Cosmic Cube there. During the battle, Thanos mortally injures Rhodes. In the aftermath, Iron Man is enraged at Captain Marvel that Ulysses' powers were used to ambush Thanos in an endeavor that cost them Rhodes' life.


title: War Machine

text: Immediately prior to re-emerging as Iron Man after suffering near-fatal injuries at the end of the "Civil War II" storyline, it is revealed that the same DNA-altering methods Tony Stark has used to heal himself he has also employed on the body of Rhodes, effectively restoring him to life. They then return to action in tandem. However, Rhodes suffers from PTSD over dying in the suit and being heavily injured numerous times and chooses to quit as War Machine and instead pilots a larger mech suit called Manticore. He soon learned that Punisher had been using his previous War Machine suit to kill the remaining Hydra remnants due to being manipulated by them during their Secret Empire. Rhodes manages to convince Punisher to return his armor and surrender to the authorities.


title: War Machine

text: During the "Iron Man 2020" event, War Machine tells the authorities that he does not know where Tony Stark is. The artificial simulation of Tony Stark has not returned War Machine's calls. When the A.I. Army was causing their acts of activism, War Machine became a member of Force Works. Following a mission that leaves Gauntlet hospitalized and Solo leaving the team, War Machine leads Quake, U.S. Agent, and Mockingbird on a mission to the island of Lingares where they are ambushed by Deathloks. War Machine, Quake, U.S. Agent, and Mockingbird have been captured by the Deathloks. They are thrown in a cage with some soldiers. Quake states to the soldiers that the dead that captured them are Deathloks. With Quake translating, War Machine, U.S. Agent, and Mockingbird learned that someone called the "Scientist" showed up claiming to help them where he made Deathloks from the fallen countrymen to help deal with a giant. Unfortunately, something went wrong. The Deathloks come in to take some men causing Force Works to fight back. More Deathloks arrive and use their electrical guns to stun them. As the Deathloks start to take War Machine, Quake recovers from the paralysis first and starts to shake the ground without her gauntlets. War Machine fights off his paralysis and starts fighting the Deathloks trying to experiment on him until he is saved by someone he recognizes who is in need of his services. Moments later, War Machine arrives with his armor, U.S. Agent's shield, and the equipment of Quake and Mockingbird as he fights off the Deathloks. As Ultimo continues his attack on the Deathloks, the rest of Force Works learned that War Machine's rescuer is MODOK Superior.


title: War Machine

text: During the "Empyre" storyline, War Machine is recruited to Captain Marvel's personal Accuser Corps and receives a copy of the Universal Weapon that was made by Doctor Strange.


title: War Machine

text: Rhodes was trained as an aircraft pilot and studied aviation engineering while in service with the United States Marine Corps. He is knowledgeable in aircraft operation/maintenance and has piloted various aircraft at Stark Enterprises. Rhodes is an experienced Marine trained in unarmed combat and military weaponry such as small arms. In addition to being a pilot, engineer, Marine, and businessman, Rhodes derives multiple abilities from various hi-tech armors, either designed by Stark Industries or extraterrestrial in nature. With his years of experience with both the Iron Man and War Machine powered armors, Rhodes is skilled in armored combat and uses a more physical fighting style. Compared to Iron Man, his suit is bulkier than Stark's and most of the time physically stronger but slower. Due to being an early Stark design and updated less than Stark's his suit generally has less cutting-edge tech functions than Iron Man.


title: War Machine

text: Rhodes' first armor as Iron Man was a solar charged carbon-composite based steel mesh armor which provided him with superhuman-level strength and durability. It was armed with repulsors in each palm of the armor's gauntlets and a multifunctional unibeam projector in the chest.


title: War Machine

text: The original Variable Threat Response Battle Suit Mark I was a version of the Iron Man armor utilizing laser guided munitions. Stark gave Rhodes a modified version of the armor, Mark II Model JRXL-1000, created just for him with the inclusion of repulsors and a unibeam projector. The armor could be modified with various modular weapons and has an improved tactical computer system with automatic targeting. Additional weapons included pulse bolt generators, retractable shoulder minigun, variable-configured double-barrel cannons on each gauntlet, gauntlet mounted flamethrower, plasma blade on the left gauntlet, missile box launcher, micro-rocket launcher, particle beam discharger, and an electromagnetic pulse generator in the unibeam projector that could shut down any electronic device in a 50-mile radius. The armor also included a photon emitter that created a force shield, forcefield-based stealth technology, boot-jet propulsion, and a self-contained breathing system.


title: War Machine

text: The second version of the armor, reconfigured by Stark, contained upgraded improvements such as heat seeking missile launchers, pulse cannon, and retractable weapon pods located on its back. Rhodes utilized different types of specialty ammunition as well as non-lethal weapons such as rubber bullets. Though Rhodes lost the original armor, he still possessed a functional prototype helmet and gauntlet.


title: War Machine

text: The armor is a symbiotic bio-armor system of alien origin and provided Rhodes with superhuman strength, durability, and speed. The armor responded to Rhodes' commands and created weapons based on his thoughts and needs. When inactive, it was concealed inside a "mandala" or tattoo-like mark on Rhodes' chest. The left arm is capable of firing destructive energy blasts while the right arm is able to morph into a blade. The armor can "unskin" remote drones that are capable of feats such as discharging various types of energy, infiltrating electronic/computer systems, creating energy fields, and completing basic tasks. If the drones are destroyed, Rhodes feels pain due to the symbiotic connection. The armor can morph into a "full battle mode," which provided unspecified enhancement to both the armor and Rhodes himself. It was also capable of space travel with an unlimited life support system. During battle, the armor would have the strange ability to "sing" alien war songs.


title: War Machine

text: During the "Sentinel Squad O*N*E" series, he used an armor that was similar to the design of previous Iron Man powered armors and was based on the primary Sentinel piloted armors that the squad used in combat. The armor was derived of S.H.I.E.L.D. technology and Stark-designed upgrades. Rhodes also piloted a larger advanced Sentinel model codenamed "War Machine". The armors were constructed of a unique mix of steel and fiberglass and contained many offensive and defensive improvements in weaponry and enhancements.


title: War Machine

text: Used during "Avengers: The Initiative" to volume two of "War Machine", this version of the War Machine armor shows all the abilities of the previous iterations with bleeding edge military ballistics and weaponry. Unlike previous War Machine armors, the armor incorporated onerousness cybernetic replacements integrated both into the character and the armor itself. James's advanced bionic components derived from Obadiah Stane's reverse engineering of older Iron Man armor that made him immune to any Starktech based systems attack. Rhodes' bionic extremities required an added life support system with integrated implants linked to the armor's systems. The armor and his endo-mantle are composed of alloys such as titanium and Wakandan vibranium, coated for stealth capabilities, and capable of space and underwater travel. Armaments included sonic generators, pulse bolts, a minigun, and a retractable unibeam projector. The technology comprising both it and its wearer can interface with any system and has interlocking capabilities that integrated mechanical constructs to repair and upgrade Rhodey and his suit. During the second "War Machine" series, Rhodes used this ability to merge with jet fighters and tanks deliberately to gain their technology and weapons. He even temporarily assimilated and expanded on his technoforming through a new form of Techno-Organic Virus, creating whole new mechanical apparatuses for him to use. At the end of the series, Rhodes (now in a cloned version of his body) is seen wearing a non-cybernetic version of the armor.


title: War Machine

text: Coming in the form of a massive Satellite Array Tony Stark had built in secret while head of S.H.I.E.L.D. Not even the spy organizations upper echelons nor their governmental backers were aware of its construction. Envisioning a potential extinction level threat to global security on the horizon, a prediction come true during the Secret Invasion. Stark had created the ultimate defensive array for Rhodey's personal use, a privately owned stealth satellite created behind closed doors that would act as a last line of defense for earth. Patterned after the same Stanetech his Initiative Armor is derived from, James could interlock his cyborg components with the stealth ancillary in order to keep his bionic replacements up and running as well as fuel up the bionics keeping him alive. Through the War Machine Satellite he remains keyed to the grid, constantly streamlining terabytes of raw data the world over without fear of intrusion by outside forces. Connected too yet insulated from the rest of the system, per Stark's recorded message. When commanded this sputnik can transform into a convertible extension of Rhodey's War Machine Armor, becoming a massive Iron Man Model chassis with which to take out entire fleets of space ships. Being one of the most powerful armors Stark has ever created, it mimics much of the War Machine model's functions and weapons systems but massively scaled up. Boasting a giant shoulder mounted cannon & nuclear missile pod, repulsor and unibeam technology and a pincer claw with which to grab and crush opposing vessels. It also boasted protective shielding to defend against destroyer class vessel armory.


title: War Machine

text: Used during issues of "Secret Avengers" and appearances in other comic series, this upgraded incarnation of the Variable Threat Response Battle Suit has a similar design to the movie version of the War Machine armor with armaments similar to previous incarnations such as a retractable shoulder minigun, repulsor technology, and shoulder missile launcher. The armor was destroyed by a nuclear attack in the first arc of the series "Iron Man 2.0". A new version of the armor was created after the short-lived "Iron Man 2.0" and "Iron Patriot" series.


title: War Machine

text: Created in the series "Iron Man 2.0" by Tony Stark, this War Machine armor is a complete redesign after the destruction of the previous model. Designed by "Iron Man 2.0" artist Barry Kitson, the armor emphasizes stealth, recon, infiltration, and combat readiness. Unlike its predecessors, it is a slimmed down armor with no visible external weaponry such as shoulder miniguns or missile launchers. The armor's color scheme is gunmetal with black detailing and has two lines on the helmet's left eye area that glows according to the repulsor reactor's color. The armor utilizes upgraded technology such as an updated Chameleon Mode (previously a feature of the "Silver Centurion" Iron Man armor) for optical invisibility, holographic projection, and camouflage purposes. The armor also possesses Ghost technology to phase through solid objects, scanner invisibility to become undetectable to all targeting systems, and a Combat Mode that can deploy weaponry which is normally hidden and increase the size and bulk of the armor. But the armor has limitations such as strain of the armor's repulsor reactor, disorientation from the Chameleon Mode, and the inability to be both invisible and intangible at the same time due to a compatibility issue.


title: War Machine

text: Patterned after Norman Osborn's Iron Patriot armor, this suit is stated to be a prototype model by Rhodes. In addition to shoulder-mounted machine guns, the armor possesses whip-like electroshock weapons that can incapacitate targets. The armor has also demonstrated camouflage and stealth abilities similar to those of the Iron Man 2.0 model.


title: War Machine

text: A high powered multipurpose assault vehicle design thought up by Stark Industries yet sold off by internal moles to Baintronics, Inc. A.I. operated as well as slated for manual operation, The Manticore is stacked to the brim with an amalgam of Bain/Stark technologies incorporated into its construction. In the initial campaign of a performance display to waiting military contractors Iron Man and War Machine would interrupt the demonstration set by rival company head Sunset Bain to any potential buyers after he had found his company secrets had been stolen. As the situation spiraled out of control and Rhodey was left vulnerable due to compounded trauma from his years operating armored suits since his resurrection. The now pilotless mobile tank ran amok without a pilot to operate its functions; needing a change of pace, Jim took the Manticore as his new weapon of choice to compensate for his armor phobia. The automotive itself is outfitted with flight and submersible capabilities, having a host of weaponry capable of taking down helicopters, tanks and even minuscule targets with pinpoint accuracy. Both lethal armaments ranging towards microwave beam-rifles, Gatling guns and missile pods. As well as nonlethal alternatives such as containment foam, soft projectiles for crowd suppression and rubber bullets for dealing with hardier foes without extinguishing their lives.


title: War Machine

text: In the Marvel Noir universe, James "Jimmy" Rhodes appears as Tony Stark's assistant/friend in the mini-series "Iron Man: Noir". In the final issue, he wears and uses a smaller, more stream-lined armor, outfitted with Gatling guns.


title: War Machine

text: In "", there is a character named Rhodes, a Moor who is the engineer of the armor worn by the Spanish nobleman Lord Iron. Rhodes accompanied Lord Iron to the New World and assists in Lord Iron's mission to hunt down David Banner, former advisor to King James I of England and the man who tortured Lord Iron when he was captured by the British.


title: War Machine

text: In the Amalgam Comics Universe created by Marvel Comics and DC Comics, there is a character named Stewart Rhodes who appears in the comic "Iron Lantern" #1. A pilot and engineer employed at Stark Aircraft, he knows the secret of Hal Stark's double life as Iron Lantern. Stewart Rhodes is the amalgam of James Rhodes and John Stewart.


title: War Machine

text: In "", War Machine is seen on the S.H.I.E.L.D. Helicarrier as a hero that initially survived the zombie plague. He is seen battling zombies, but to prevent infection within him, he ultimately retreats to the helicarrier. Though he is not much seen, his fate is not yet depicted.


title: War Machine

text: In "Marvel Zombies Return", Zombie Giant Man finds a way to enter parallel universes and invades a universe that resembles the time period in which Tony Stark was an alcoholic. Giant Man infected the parallel universe's Happy Hogan, Pepper Potts and a number of people at Stark Industries. The James Rhodes from the parallel universe finds the Iron Man armor located in a bathroom and puts it on to reach Stark. After Stark sacrifices himself to kill as many zombies as possible, Rhodes takes the name Iron Man and announces he will help the police fend off the zombies. He also becomes a member of this reality's Illuminati. Years later, Rhodes joins the New Avengers in a heavily armed suit reminiscent of the War Machine armor but in the Iron Man color scheme. This Rhodes is at least partly cybernetic, having escaped falling victim to the zombie virus himself by cutting off any of his limbs that has been infected after being bitten in order to protect himself from the virus, the armor consisting at least partly of cybernetic limbs rather than just a simple suit. The New Avengers team assembled consists of Iron Man and the zombified Spider-Man, Hulk and Wolverine. As part of this, he killed some of the Sentry and Giant Man's undead group team members of the "Avengers". Then, using a nanite virus now infused in Sandman that can kill the zombies forever by engulfing and eating away dead flesh and tissue which is intentionally developed by Spider-Man, the team defeats the zombie Avengers, eradicating the zombie menace for good. He is seen as the last survivor, along with Sandman and Uatu on the last series.


title: War Machine

text: In the MC2 alternate future, Rhodes gained superhuman powers after exposing himself to experimental microscopic robots. While Tony Stark had intended to test them on himself, Rhodes did not feel it would be right for Stark to unnecessarily risk his life. Although now blessed with exponentially-increasing invulnerability and an impressive array of energy-based attacks, the nanites slowly corrupt Rhodes' mind, eventually destroying his personality and leaving him as little more than a very powerful, humanoid robot. He eventually works as a personal bodyguard for Tony Stark, and although he adopts a superhero uniform (vaguely reminiscent of Superman, though with a different color scheme and no chest insignia) neither he nor Stark bother to come up with a moniker for him. Spider-Girl refers to him as "Fred" for most of her series, for simple lack of anything else to call him.


title: War Machine

text: In the alternate-reality MAX imprint series "U.S. War Machine", Tony Stark announces he is retiring from developing weapons after he and his bodyguard Jim Rhodes, who had piloted the MPI-2100 Mobile Infantry Suit a.k.a. the "War Machine" armor, had used lethal force in the defeat of foreign tyrant Doctor Doom's armies. He stated he was mothballing the War Machine armor and presented the SI1-211 "Iron Man" as his new bodyguard. Rhodes, however, uses the War Machine armor to fight rogue agents of the terrorist group Advanced Idea Mechanics, and after killing two of them is fired by Stark. Afterward, former War Machine pilot Parnell Jacobs attacks Rhodes at home in an attempt to steal the War Machine armor. After Rhodes defeats Jacobs, Colonel Nick Fury, head of the espionage agency S.H.I.E.L.D., has Rhodes and Jacobs brought in to the agency's headquarters, the Skycarrier.


title: War Machine

text: Jacobs reveals that his wife, Glenda Sandoval, was taken hostage by A.I.M., with the promise of release if Jacobs delivered the original War Machine armor. But Jacobs had sold that armor to another terrorist group, HYDRA, to gain money when he learned his wife was pregnant. S.H.I.E.L.D. retrieves the armor from HYDRA and, with the guidance of 12-year-old-genius armament designer "Scotch", reverse-engineers its technology to create its own version of the War Machine armor for a planned Special Operations division, dubbed "U.S. War Machine", with Rhodes in charge. Targeting A.I.M., the team includes Jacobs, Dum Dum Dugan, and Sheva Josephs.


title: War Machine

text: In the sequel series "U.S. War Machine 2.0.", Stark is furious that S.H.I.E.L.D.'s U.S. War Machine division exists and combats it as Iron Man accompanied by his own armored forces—Happy Hogan, Bethany Cabe, and Eddie March—in MPI-2100 Mobile Infantry Suits. Rhodes, now a major, and his division team with Captain America (James "Bucky" Barnes), Sam Wilson, and Clint Barton, to stop Doctor Doom from detonating stolen nuclear weapons planted on the Millennium Wheel in London.


title: War Machine

text: In the Ultimate Marvel reality, Jim Rhodes first appears as a prep school student and the victim of frequent bullying at the school due to his ethnicity. He comes from a poorer family and the fact that he is there because of the school's racial quota. He finds an unlikely friend in young Tony Stark who defends him against the bullies – much to his dismay because it only serves to attract more attention to himself and, thus, increase his torment. Stark is keen on Rhodes being his friend, while Rhodes, initially, is uneasy about Stark and his burgeoning friendship. Later, after Stark is severely attacked at school and is aided by Rhodes (which turns out to be a peripheral attack on Stark's father), both leave the school and with Stark's father's help, are accepted into the Baxter Building's School for Exceptional Children along with Rhodes's sister, one, because they are all strikingly intelligent, but also for their own protection. Both begin work on different projects and eventually, Stark takes Rhodes into his confidence and allows Rhodes a chance to wear and help design some of the armor he and his father have innovated. Rhodes and Stark's friendship strengthens and Rhodes is later seen making another armor version named "War Machine" which he is going to trade with Stark's "Iron Man" armor when both are fully developed. A couple of years later, Stark and Rhodes, in their respective armor, team up as fake "robots" to take out a terrorist group for the government. This origin, however, was retconned as being a fictionalized history of Tony Stark's early years.


title: War Machine

text: The actual Ultimate Marvel version of James Rhodes is a Sergeant Major in the armed forces and is seen sporting War Machine armor created by Gregory Stark. Both Rhodey and Tony are, for some reason, estranged, later revealed he never received likeness for the "Ultimate Iron Man" cartoon. War Machine saves two abducted U.S. Army officers from the hands of the terrorists. Once the officers had been secured, Rhodes decides to kill the unarmed civilians and the enemy after they surrendered, giving the first glimpse into a more ruthless, apathetic and even sadistic incarnation that's a far cry from earlier views of the character. Later, in France, he attempts to capture Captain America as part of the with new armor that is quite larger, is bloated with numerous ballistic weapons, and can even transform into a German sports car. Rhodes is almost able to capture Captain America, but their last confrontation involves Cap being in a room full of school children. His ruthlessness is shown ever further as he contemplates continuing his attack, until Captain America reminds him that any "Collateral Damage" involving school children would be a Public Relations and Political nightmare prompting War Machine to back off, but for all the wrong reasons. He continues to work for Nick Fury, also recruiting Tyrone Cash during the Ghost Rider incident, and is one of the last Avengers (with Hawkeye, Blade, and Punisher) led by Fury, until his return to S.H.I.E.L.D. Director. , he was seen testing new Stark drones for the Air Force and was approached by Iron Man, with whom he apparently reconciled, to ask him for help against the Mandarin International. He later dons a more simplified War Machine armor, and teams with S.H.I.E.L.D. to free Stark from the Mandarin's Hong Kong facility, after then they rekindled their friendship.


title: War Machine

text: A future equivalent of War Machine is Howard Anthony Stark, the son of Tony Stark and Pepper Potts. He is seen as a cyborg in his own Iron Man armor during a flashforward to an apocalyptic future 41 years ahead where the Mandarin has conquered the world. Howard protects his daughter Ginny Stark while his aged father defeats the Mandarin, sacrificing themselves in the process. At the story's close, Howard gets buried in a gravestone next his mother and father by Ginny. Howard is also said to be 41 years old, suggesting that Howard will be born within the present time.


title: War Machine

text: During the 2015 "Secret Wars" storyline, a version of Jim Rhodes is a member of the Thor Corps and the Grand Marshall of Baron Stark's region of Battleworld called Technopolis. he also was referred to as iron hammer .


title: War Machine

text: After Rhodes' death in Civil War II, America Chavez takes Kate Bishop to a number of alternate realities during his funeral to show the fates of different versions of him. Earth-55 Rhodes became Iron Man after Stark's death and leads the Avengers. Earth-727 Rhodes became the mayor of Philadelphia after his military career ended. Earth-57289 Rhodes is the C.E.O. of Rhodes Labs International, where Tony Stark works as a scientist. Finally an unknown Earth where Rhodes married Carol Danvers (whom 616 Rhodes was dating before his death).


title: War Machine

text: In the "Spider-Gwen" universe (Earth-65), "War Machine" refers to the private army of Tony Stark. The Earth-65 version of Frank Castle, a cop on the NYPD, is a former member of War Machine.


title: War Machine

text: Some time after the events of Secret Empire, Nick Fury Jr. gives The Punisher access to the War Machine armor in order to combat a rogue state that was caught using old S.H.I.E.L.D. resources. During the aftermath of the operation, Castle resumes his war on crime in New York with the War Machine armor for a brief period of time until his arrest by Fury. The armor is then returned to a recently revived Rhodes.


title: War Machine

text: Terrence Howard and Don Cheadle portrayed James Rhodes / War Machine in the Marvel Cinematic Universe.


title: Tsiolkovsky rocket equation

text: The classical rocket equation, or ideal rocket equation is a mathematical equation that describes the motion of vehicles that follow the basic principle of a rocket: a device that can apply acceleration to itself using thrust by expelling part of its mass with high velocity can thereby move due to the conservation of momentum.


title: Tsiolkovsky rocket equation

text: It is credited to the Russian scientist Konstantin Tsiolkovsky () who independently derived it and published it in 1903, although it had been independently derived and published by the British mathematician William Moore in 1810, and later published in a separate book in 1813. American Robert Goddard also developed it independently in 1912, and German Hermann Oberth derived it independently about 1920.


title: Tsiolkovsky rocket equation

text: Given the effective exhaust velocity determined by the rocket motor's design, the desired delta-v (e.g. orbital speed or escape velocity), and a given dry mass formula_8, the equation can be solved for the required propellant mass formula_10:


title: Tsiolkovsky rocket equation

text: The equation is named after Russian scientist Konstantin Tsiolkovsky who independently derived it and published it in his 1903 work.


title: Tsiolkovsky rocket equation

text: The equation had been derived earlier by the British mathematician William Moore in 1810, and later published in a separate book in 1813.


title: Tsiolkovsky rocket equation

text: American Robert Goddard independently developed the equation in 1912 when he began his research to improve rocket engines for possible space flight. German engineer Hermann Oberth independently derived the equation about 1920 as he studied the feasibility of space travel.


title: Tsiolkovsky rocket equation

text: While the derivation of the rocket equation is a straightforward calculus exercise, Tsiolkovsky is honored as being the first to apply it to the question of whether rockets could achieve speeds necessary for space travel.


title: Tsiolkovsky rocket equation

text: In order to understand the principle of rocket propulsion, Konstantin Tsiolkovsky proposed the famous experiment "of the boat". A person is in a boat away from the shore without oars. They want to reach this shore. They notice that the boat is loaded with a certain quantity of stones and have the idea of throwing, one by one and as quickly as possible, these stones in the opposite direction to the bank. Effectively, the quantity of movement of the stones thrown in one direction corresponds to an equal quantity of movement for the boat in the other direction.


title: Tsiolkovsky rocket equation

text: In the following derivation, "the rocket" is taken to mean "the rocket and all of its unexpended propellant".


title: Tsiolkovsky rocket equation

text: Newton's second law of motion relates external forces (formula_12) to the change in linear momentum of the whole system (including rocket and exhaust) as follows:


title: Tsiolkovsky rocket equation

text: The velocity of the exhaust formula_24 in the observer frame is related to the velocity of the exhaust in the rocket frame formula_31 by (since exhaust velocity is in the negative direction)


title: Tsiolkovsky rocket equation

text: Assuming that formula_31 is constant (known as the Tsiolkovsky's hypothesis), so it is not subject to integration, then the above equation may be integrated as follows:


title: Tsiolkovsky rocket equation

text: where formula_7 is the initial total mass including propellant, formula_8 the final mass, and formula_31 the velocity of the rocket exhaust with respect to the rocket (the specific impulse, or, if measured in time, that multiplied by gravity-on-Earth acceleration). If formula_31 is NOT constant, we might not have rocket equations that are as simple as the above forms. Many rocket dynamics researches were based on the Tsiolkovsky's constant formula_31 hypothesis.


title: Tsiolkovsky rocket equation

text: formula_51 (delta v) is the integration over time of the magnitude of the acceleration produced by using the rocket engine (what would be the actual acceleration if external forces were absent). In free space, for the case of acceleration in the direction of the velocity, this is the increase of the speed. In the case of an acceleration in opposite direction (deceleration) it is the decrease of the speed. Of course gravity and drag also accelerate the vehicle, and they can add or subtract to the change in velocity experienced by the vehicle. Hence delta-v may not always be the actual change in speed or velocity of the vehicle.


title: Tsiolkovsky rocket equation

text: The equation can also be derived from the basic integral of acceleration in the form of force (thrust) over mass.


title: Tsiolkovsky rocket equation

text: where T is thrust, formula_7 is the initial (wet) mass and formula_35 is the initial mass minus the final (dry) mass,


title: Tsiolkovsky rocket equation

text: and realising that the integral of a resultant force over time is total impulse, assuming thrust is the only force involved,


title: Tsiolkovsky rocket equation

text: Realising that impulse over the change in mass is equivalent to force over propellant mass flow rate (p), which is itself equivalent to exhaust velocity,


title: Tsiolkovsky rocket equation

text: Imagine a rocket at rest in space with no forces exerted on it (Newton's First Law of Motion). From the moment its engine is started (clock set to 0) the rocket expels gas mass at a "constant mass flow rate R" (kg/s) and at "exhaust velocity relative to the rocket v" (m/s). This creates a constant force "F" propelling the rocket that is equal to "R" × "v". The rocket is subject to a constant force, but its total mass is decreasing steadily because it is expelling gas. According to Newton's Second Law of Motion, its acceleration at any time "t" is its propelling force "F" divided by its current mass "m":


title: Tsiolkovsky rocket equation

text: Now, the mass of fuel the rocket initially has on board is equal to "m" – "m". For the constant mass flow rate "R" it will therefore take a time "T = (m – m)/R" to burn all this fuel. Integrating both sides of the equation with respect to time from "0" to "T" (and noting that "R = dm/dt" allows a substitution on the right), we obtain


title: Tsiolkovsky rocket equation

text: The rocket equation can also be derived as the limiting case of the speed change for a rocket that expels its fuel in the form of formula_61 pellets consecutively, as formula_62, with an effective exhaust speed formula_63 such that the mechanical energy gained per unit fuel mass is given by formula_64.


title: Tsiolkovsky rocket equation

text: In the rocket's center-of-mass frame, if a pellet of mass formula_65 is ejected at speed formula_66 and the remaining mass of the rocket is formula_28, the amount of energy converted to increase the rocket's and pellet's kinetic energy is


title: Tsiolkovsky rocket equation

text: Using momentum conservation in the rocket's frame just prior to ejection, formula_69, from which we find


title: Tsiolkovsky rocket equation

text: Let formula_71 be the initial fuel mass fraction on board and formula_72 the initial fueled-up mass of the rocket. Divide the total mass of fuel formula_73 into formula_61 discrete pellets each of mass formula_75. The remaining mass of the rocket after ejecting formula_76 pellets is then formula_77. The overall speed change after ejecting formula_76 pellets is the sum


title: Tsiolkovsky rocket equation

text: Notice that for large formula_61 the last term in the denominator formula_81 and can be neglected to give


title: Tsiolkovsky rocket equation

text: If special relativity is taken into account, the following equation can be derived for a relativistic rocket, with formula_1 again standing for the rocket's final velocity (after expelling all its reaction mass and being reduced to a rest mass of formula_89) in the inertial frame of reference where the rocket started at rest (with the rest mass including fuel being formula_7 initially), and formula_91 standing for the speed of light in a vacuum:


title: Tsiolkovsky rocket equation

text: Then, using the identity formula_96 (here "exp" denotes the exponential function; "see also" Natural logarithm as well as the "power" identity at Logarithmic identities) and the identity formula_97 ("see" Hyperbolic function), this is equivalent to


title: Tsiolkovsky rocket equation

text: Delta-"v" (literally "change in velocity"), symbolised as Δ"v" and pronounced "delta-vee", as used in spacecraft flight dynamics, is a measure of the impulse that is needed to perform a maneuver such as launching from, or landing on a planet or moon, or an in-space orbital maneuver. It is a scalar that has the units of speed. As used in this context, it is "not" the same as the physical change in velocity of the vehicle.


title: Tsiolkovsky rocket equation

text: Delta-"v" is produced by reaction engines, such as rocket engines and is proportional to the thrust per unit mass, and burn time, and is used to determine the mass of propellant required for the given manoeuvre through the rocket equation.


title: Tsiolkovsky rocket equation

text: For interplanetary missions delta-"v" is often plotted on a porkchop plot which displays the required mission delta-"v" as a function of launch date.


title: Tsiolkovsky rocket equation

text: In aerospace engineering, the propellant mass fraction is the portion of a vehicle's mass which does not reach the destination, usually used as a measure of the vehicle's performance. In other words, the propellant mass fraction is the ratio between the propellant mass and the initial mass of the vehicle. In a spacecraft, the destination is usually an orbit, while for aircraft it is their landing location. A higher mass fraction represents less weight in a design. Another related measure is the payload fraction, which is the fraction of initial weight that is payload.


title: Tsiolkovsky rocket equation

text: The effective exhaust velocity is often specified as a specific impulse and they are related to each other by:


title: Tsiolkovsky rocket equation

text: The rocket equation captures the essentials of rocket flight physics in a single short equation. It also holds true for rocket-like reaction vehicles whenever the effective exhaust velocity is constant, and can be summed or integrated when the effective exhaust velocity varies. The rocket equation only accounts for the reaction force from the rocket engine; it does not include other forces that may act on a rocket, such as aerodynamic or gravitational forces. As such, when using it to calculate the propellant requirement for launch from (or powered descent to) a planet with an atmosphere, the effects of these forces must be included in the delta-V requirement (see Examples below). In what has been called "the tyranny of the rocket equation", there is a limit to the amount of payload that the rocket can carry, as higher amounts of propellant increment the overall weight, and thus also increase the fuel consumption. The equation does not apply to non-rocket systems such as aerobraking, gun launches, space elevators, launch loops, tether propulsion or light sails.


title: Tsiolkovsky rocket equation

text: The rocket equation can be applied to orbital maneuvers in order to determine how much propellant is needed to change to a particular new orbit, or to find the new orbit as the result of a particular propellant burn. When applying to orbital maneuvers, one assumes an impulsive maneuver, in which the propellant is discharged and delta-v applied instantaneously. This assumption is relatively accurate for short-duration burns such as for mid-course corrections and orbital insertion maneuvers. As the burn duration increases, the result is less accurate due to the effect of gravity on the vehicle over the duration of the maneuver. For low-thrust, long duration propulsion, such as electric propulsion, more complicated analysis based on the propagation of the spacecraft's state vector and the integration of thrust are used to predict orbital motion.


title: Tsiolkovsky rocket equation

text: Assume an exhaust velocity of and a formula_1 of (Earth to LEO, including formula_1 to overcome gravity and aerodynamic drag).


title: Tsiolkovsky rocket equation

text: In the case of sequentially thrusting rocket stages, the equation applies for each stage, where for each stage the initial mass in the equation is the total mass of the rocket after discarding the previous stage, and the final mass in the equation is the total mass of the rocket just before discarding the stage concerned. For each stage the specific impulse may be different.


title: Tsiolkovsky rocket equation

text: For example, if 80% of the mass of a rocket is the fuel of the first stage, and 10% is the dry mass of the first stage, and 10% is the remaining rocket, then


title: Tsiolkovsky rocket equation

text: A comparable SSTO rocket, also with a 0.1% payload, could have a mass of 11.1% for fuel tanks and engines, and 88.8% for fuel. This would give


title: Tsiolkovsky rocket equation

text: If the motor of a new stage is ignited before the previous stage has been discarded and the simultaneously working motors have a different specific impulse (as is often the case with solid rocket boosters and a liquid-fuel stage), the situation is more complicated.


title: Tsiolkovsky rocket equation

text: When viewed as a variable-mass system, a rocket cannot be directly analyzed with Newton's second law of motion because the law is valid for constant-mass systems only. It can cause confusion that the Tsiolkovsky rocket equation looks similar to the relativistic force equation formula_114. Using this formula with formula_115 as the varying mass of the rocket seems to derive the Tsiolkovsky rocket equation, but this derivation is not correct. Notice that the effective exhaust velocity formula_31 does not even appear in this formula.


title: Insulin-like growth factor 1

text: Insulin-like growth factor 1 (IGF-1), also called somatomedin C, is a hormone similar in molecular structure to insulin which plays an important role in childhood growth, and has anabolic effects in adults.


title: Insulin-like growth factor 1

text: IGF-1 is a protein that in humans is encoded by the "IGF1" gene. IGF-1 consists of 70 amino acids in a single chain with three intramolecular disulfide bridges. IGF-1 has a molecular weight of 7,649 Daltons. In dogs, an ancient mutation in IGF1 is the primary cause of the toy phenotype.


title: Insulin-like growth factor 1

text: IGF-1 is produced primarily by the liver. Production is stimulated by growth hormone (GH). Most of IGF-1 is bound to one of 6 binding proteins (IGF-BP). IGFBP-1 is regulated by insulin. IGF-1 is produced throughout life; the highest rates of IGF-1 production occur during the pubertal growth spurt. The lowest levels occur in infancy and old age.


title: Insulin-like growth factor 1

text: Cyclic glycine-proline (cGP) is metabolite of hormone Insulin-like Growth Factor-1 (IGF-1). It has a cyclic structure, lipophilic nature, and is enzymatically stable which makes its a more favourable candidate for manipulating the binding-release process between IGF-1 and its binding protein thereby, normalising IGF-1 function.


title: Insulin-like growth factor 1

text: IGF-1 is produced primarily by the liver as an endocrine hormone as well as in target tissues in a paracrine/autocrine fashion. Production is stimulated by growth hormone (GH) and can be retarded by undernutrition, growth hormone insensitivity, lack of growth hormone receptors, or failures of the downstream signaling pathway post GH receptor including SHP2 and STAT5B. Approximately 98% of IGF-1 is always bound to one of 6 binding proteins (IGF-BP). IGFBP-3, the most abundant protein, accounts for 80% of all IGF binding. IGF-1 binds to IGFBP-3 in a 1:1 molar ratio. IGFBP-1 is regulated by insulin.


title: Insulin-like growth factor 1

text: IGF-1 is produced throughout life. The highest rates of IGF-1 production occur during the pubertal growth spurt. The lowest levels occur in infancy and old age.


title: Insulin-like growth factor 1

text: Protein intake increases IGF-1 levels in humans, independent of total calorie consumption. Factors that are known to cause variation in the levels of growth hormone (GH) and IGF-1 in the circulation include: insulin levels, genetic make-up, the time of day, age, sex, exercise status, stress levels, nutrition level and body mass index (BMI), disease state, ethnicity, estrogen status and xenobiotic intake.


title: Insulin-like growth factor 1

text: IGF-1 is a primary mediator of the effects of growth hormone (GH). Growth hormone is made in the anterior pituitary gland, is released into the blood stream, and then stimulates the liver to produce IGF-1. IGF-1 then stimulates systemic body growth, and has growth-promoting effects on almost every cell in the body, especially skeletal muscle, cartilage, bone, liver, kidney, nerve, skin, hematopoietic, and lung cells. In addition to the insulin-like effects, IGF-1 can also regulate cellular DNA synthesis.


title: Insulin-like growth factor 1

text: IGF-1 binds to at least two cell surface receptor tyrosine kinases: the IGF-1 receptor (IGF1R), and the insulin receptor. Its primary action is mediated by binding to its specific receptor, IGF1R, which is present on the surface of many cell types in many tissues. Binding to the IGF1R initiates intracellular signaling. IGF-1 is one of the most potent natural activators of the AKT signaling pathway, a stimulator of cell growth and proliferation, and a potent inhibitor of programmed cell death . The IGF-1 receptor seems to be the "physiologic" receptor because it binds IGF-1 with significantly higher affinity than insulin receptor does. IGF-1 activates the insulin receptor at approximately 0.1 times the potency of insulin. Part of this signaling may be via IGF1R/Insulin Receptor heterodimers (the reason for the confusion is that binding studies show that IGF1 binds the insulin receptor 100-fold less well than insulin, yet that does not correlate with the actual potency of IGF1 in vivo at inducing phosphorylation of the insulin receptor, and hypoglycemia).


title: Insulin-like growth factor 1

text: IGF-1 binds and activates its own receptor, IGF-1R, through the cell surface expression of Receptor Tyrosine Kinase's (RTK's) and further signal through multiple intracellular transduction cascades. IGF-1R is the critical role-playing inducer in modulating the metabolic effects of IGF-1 for cellular senescence and survival. At a localized target cell, IGF-1R elicits the mediation of paracrine activity. After its activation the initiation of intracellular signaling occurs inducing a magnitude of signaling pathways. An important mechanistic pathway involved in mediating a cascade affect a key pathway regulated by phosphatidylinositol-3 kinase (PI3K) and its downstream partner, mTOR (mammalian Target of Rapamycin). Rapamycin binds with the enzyme FKBPP12 to inhibit the mTORC1 complex. mTORC2 remains unaffected and responds by up-regulating AKT, driving signals through the inhibited mTORC1. Phosphorylation of Eukaryotic translation initiation factor 4E (EIF4E) by mTOR suppresses the capacity of Eukaryotic translation initiation factor 4E-binding protein 1 (EIF4EBP1) to inhibit EIF4E and slow metabolism. A mutation in the signaling pathway PI3K-AKT-mTOR is a big factor in the formation of tumors found predominantly on skin, internal organs, and secondary lymph nodes (Kaposi sarcoma). IGF-1R allows the activation of these signaling pathways and subsequently regulates the cellular longevity and metabolic re-uptake of biogenic substances. A therapeutic approach targeting towards the reduction of such tumor collections could be induced by ganitumab. Ganitumab is a monoclonal antibody (mAb) directed antagonistically against IGF-1R. Ganitumab binds to IGF-1R, preventing binding of IGF-1 and the subsequent triggering of the PI3K-mTOR signaling pathway; inhibition of this pro-survival pathway may result in the inhibition of tumor cell expansion and the induction of tumor cell apoptosis.


title: Insulin-like growth factor 1

text: Insulin-like growth factor 1 has been shown to bind and interact with all seven IGF-1 binding proteins (IGFBPs): IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, IGFBP6, and IGFBP7.


title: Insulin-like growth factor 1

text: Some IGFBPs are inhibitory. For example, both IGFBP-2 and IGFBP-5 bind IGF-1 at a higher affinity than it binds its receptor. Therefore, increases in serum levels of these two IGFBPs result in a decrease in IGF-1 activity.


title: Insulin-like growth factor 1

text: As a major growth factor, IGF-1 is responsible for stimulating growth of all cell types and causing significant metabolic effects. One important metabolic effect of IGF-1 is its ability to signal cells that sufficient nutrients are available for cells to undergo hypertrophy and cell division. These signals also enable IGF-1 to inhibit cell apoptosis and increase the production of cellular proteins. IGF-1 receptors are ubiquitous, which allows for metabolic changes caused by IGF-1 to occur in all cell types. IGF-1's metabolic effects are far-reaching and can coordinate protein, carbohydrate, and fat metabolism in a variety of different cell types. The regulation of IGF-1's metabolic effects on target tissues is also coordinated with other hormones such as growth hormone and insulin.


title: Insulin-like growth factor 1

text: IGF-1 is closely related to a second protein called "IGF-2". IGF-2 also binds the IGF-1 receptor. However, IGF-2 alone binds a receptor called the "IGF-2 receptor" (also called the mannose-6 phosphate receptor). The insulin-like growth factor-II receptor (IGF2R) lacks signal transduction capacity, and its main role is to act as a sink for IGF-2 and make less IGF-2 available for binding with IGF-1R.


title: Insulin-like growth factor 1

text: As the name "insulin-like growth factor 1" implies, IGF-1 is structurally related to insulin, and is even capable of binding the insulin receptor, albeit at lower affinity than insulin.


title: Insulin-like growth factor 1

text: A splice variant of IGF-1 sharing an identical mature region, but with a different E domain is known as "mechano-growth factor" (MGF).


title: Insulin-like growth factor 1

text: Rare diseases characterized by inability to make or respond to IGF-1 produce a distinctive type of growth failure. One such disorder, termed Laron dwarfism does not respond at all to growth hormone treatment due to a lack of GH receptors. The FDA has grouped these diseases into a disorder called severe primary IGF deficiency. Patients with severe primary IGFD typically present with normal to high GH levels, height below 3 standard deviations (SD), and IGF-1 levels below 3 SD. Severe primary IGFD includes patients with mutations in the GH receptor, post-receptor mutations or IGF mutations, as previously described. As a result, these patients cannot be expected to respond to GH treatment.


title: Insulin-like growth factor 1

text: People with Laron syndrome have very low rates of cancer and diabetes. Notably people with untreated Laron syndrome also never develop acne.


title: Insulin-like growth factor 1

text: Acromegaly is a syndrome that results when the anterior pituitary gland produces excess growth hormone (GH). A number of disorders may increase the pituitary's GH output, although most commonly it involves a tumor called pituitary adenoma, derived from a distinct type of cell (somatotrophs). It leads to anatomical changes and metabolic dysfunction caused by both an elevated GH and elevated IGF-1 levels. High level of IGF-1 in acromegaly is related to an increased risk of some cancers, particularly colon cancer and thyroid cancer.


title: Insulin-like growth factor 1

text: A mutation in the signaling pathway PI3K-AKT-mTOR is a factor in the formation of tumors found predominantly on skin, internal organs, and secondary lymph nodes (Kaposi sarcoma).


title: Insulin-like growth factor 1

text: IGF-1R allows the activation of these signaling pathways and subsequently regulates the cellular longevity and metabolic re-uptake of biogenic substances. A therapeutic approach targeting towards the reduction of such tumor collections could be induced by ganitumab. Ganitumab is a monoclonal antibody (mAb) directed antagonistically against IGF-1R. Ganitumab binds to IGF-1R, preventing binding of IGF-1 and the subsequent triggering of the PI3K-mTOR signaling pathway; inhibition of this pro-survival pathway may result in the inhibition of tumor cell expansion and the induction of tumor cell apoptosis.


title: Insulin-like growth factor 1

text: IGF-1 levels can be measured in the blood in 10-1000 ng/ml amounts. As levels do not fluctuate greatly throughout the day for an individual person, IGF-1 is used by physicians as a screening test for growth hormone deficiency and excess in acromegaly and gigantism.


title: Insulin-like growth factor 1

text: Interpretation of IGF-1 levels is complicated by the wide normal ranges, and marked variations by age, sex, and pubertal stage. Clinically significant conditions and changes may be masked by the wide normal ranges. Sequential measurement over time is often useful for the management of several types of pituitary disease, undernutrition, and growth problems.


title: Insulin-like growth factor 1

text: Patients with severe primary insulin-like growth factor-1 deficiency (IGFD), called Laron syndrome, may be treated with either IGF-1 alone or in combination with IGFBP-3. Mecasermin (brand name Increlex) is a synthetic analog of IGF-1 which is approved for the treatment of growth failure. IGF-1 has been manufactured recombinantly on a large scale using both yeast and "E. coli".


title: Insulin-like growth factor 1

text: IGF-1 may have a beneficial effect on atherosclerosis and cardiovascular disease. IGF-1 has also been shown to have an antidepressant effect in mouse models.


title: Insulin-like growth factor 1

text: Several companies have evaluated administering recombinant IGF-1 in clinical trials for type 1 diabetes, type 2 diabetes, amyotrophic lateral sclerosis, severe burn injury and myotonic muscular dystrophy.


title: Insulin-like growth factor 1

text: Results of clinical trials evaluating the efficacy of IGF-1 in type 1 diabetes and type 2 diabetes showed reduction in hemoglobin A1C levels and daily insulin consumption. However the sponsor discontinued the program due to an exacerbation of diabetic retinopathy, coupled with a shift in corporate focus towards oncology.


title: Insulin-like growth factor 1

text: Two clinical studies of IGF-1 for ALS were conducted and although one study demonstrated efficacy the second was equivocal, and the product was not submitted for approval to the FDA.


title: Insulin-like growth factor 1

text: In the 1950s IGF-1 was called "sulfation factor" because it stimulated sulfation of cartilage in vitro, and in the 1970s due to its effects it was termed "nonsuppressible insulin-like activity" (NSILA).


title: Call sign

text: In broadcasting and radio communications, a call sign (also known as a call name or call letters—and historically as a call signal—or abbreviated as a call) is a unique identifier for a transmitter station. A call sign can be formally assigned by a government agency, informally adopted by individuals or organizations, or even cryptographically encoded to disguise a station's identity.


title: Call sign

text: The use of call signs as unique identifiers dates to the landline railroad telegraph system. Because there was only one telegraph line linking all railroad stations, there needed to be a way to address each one when sending a telegram. In order to save time, two-letter identifiers were adopted for this purpose. This pattern continued in radiotelegraph operation; radio companies initially assigned two-letter identifiers to coastal stations and stations onboard ships at sea. These were not globally unique, so a one-letter company identifier (for instance, 'M' and two letters as a Marconi station) was later added. By 1912, the need to quickly identify stations operated by multiple companies in multiple nations required an international standard; an ITU prefix would be used to identify a country, and the rest of the call sign an individual station in that country.


title: Call sign

text: Merchant and naval vessels are assigned call signs by their national licensing authorities. In the case of states such as Liberia or Panama, which are flags of convenience for ship registration, call signs for larger vessels consist of the national prefix plus three letters (for example, 3LXY, and sometimes followed by a number, i.e. 3LXY2). United States merchant vessels are given call signs beginning with the letters "W" or "K" while US naval ships are assigned call signs beginning with "N". Originally, both ships and broadcast stations were assigned call signs in this series consisting of three or four letters. Ships equipped with Morse code radiotelegraphy, or life boat radio sets, Aviation ground stations, broadcast stations were given four letter call signs. Maritime coast stations on high frequency (both radiotelegraphy and radiotelephony) were assigned three letter call signs. As demand for both marine radio and broadcast call signs grew, gradually American-flagged vessels with radiotelephony only were given longer call signs with mixed letters and numbers.


title: Call sign

text: Leisure craft with VHF radios may not be assigned call signs, in which case the name of the vessel is used instead. Ships in the US still wishing to have a radio license are under FCC class SA: "Ship recreational or voluntarily equipped." Those calls follow the land mobile format of the initial letter K or W followed by 1 or 2 letters followed by 3 or 4 numbers (such as KX0983 or WXX0029). U.S. Coast Guard small boats have a number that is shown on both bows (i.e. port and starboard) in which the first two digits indicate the nominal length of the boat in feet. For example, Coast Guard 47021 refers to the 21st in the series of 47-foot motor lifeboats. The call sign might be abbreviated to the final two or three numbers during operations, for example: "Coast Guard zero two one".


title: Call sign

text: Originally aviation mobile stations (aircraft) equipped with radiotelegraphy were assigned five-letter call signs (e.g. KHAAQ). Land stations in aviation were assigned four-letter call signs (e.g. WEAL – Eastern Air Lines, NYC.) These call signs were phased out in the 1960s when flight radio officers (FRO) were no longer required on international flights. The Russian Federation kept FROs for the Moscow-Havana run until around 2000.


title: Call sign

text: Currently, all signs in aviation are derived from several different policies, depending upon the type of flight operation and whether or not the caller is in an aircraft or at a ground facility. In most countries, unscheduled general aviation flights identify themselves using the call sign corresponding to the aircraft's registration number (also called "N-number" in the U.S., or "tail number"). In this case, the call sign is spoken using the International Civil Aviation Organization (ICAO) phonetic alphabet. Aircraft registration numbers internationally follow the pattern of a country prefix, followed by a unique identifier made up of letters and numbers. For example, an aircraft registered as "N978CP" conducting a general aviation flight would use the call sign "November-niner-seven-eight-Charlie-Papa". However, in the United States a pilot of an aircraft would normally omit saying "November", and instead use the name of the aircraft manufacturer or the specific model. At times, general aviation pilots might omit additional preceding numbers and use only the last three numbers and letters. This is especially true at uncontrolled fields (those without control towers) when reporting traffic pattern positions or at towered airports after establishing two-way communication with the tower controller. For example, "Skyhawk eight-Charlie-Papa, left base". In commercial aviation, the callsign is usually the ICAO Flight number. For example, "Delta Airlines Flight 744" would have the flight number "DL744" and the callsign would be "Delta 744".


title: Call sign

text: In most countries, the aircraft call sign or "tail number"/"tail letters" (also known as registration marks) are linked to the international radio call sign allocation table and follow a convention that aircraft radio stations (and, by extension, the aircraft itself) receive call signs consisting of five letters. For example, all British civil aircraft have a five-letter registration beginning with the letter G, which can also serve for a call sign. Canadian aircraft have a call sign beginning with C–F or C–G, such as C–FABC. wing-in-ground-effect vehicles and hovercraft in Canada are eligible to receive C–Hxxx call signs, and ultralight aircraft receive C-Ixxx call signs. In days gone by, even American aircraft used five letter call signs, such as KH–ABC, but they were replaced prior to World War II by the current American system of civilian aircraft call signs (see below). One exception to the parallelism between registration and call sign is ultralight aeroplanes in France, who are not obliged to carry a radio and indeed often don't.


title: Call sign

text: Radio call signs used for communication in crewed spaceflight are not formalized or regulated to the same degree as for aircraft. The three nations currently launching crewed space missions use different methods to identify the ground and space radio stations; the United States uses either the names given to the space vehicles, or else the project name and mission number. Russia traditionally assigns code names as call signs to individual cosmonauts, more in the manner of aviator call signs, rather than to the spacecraft.


title: Call sign

text: The only continuity in call signs for spacecraft have been the issuance of "ISS"-suffixed call signs by various countries in the amateur radio service as a citizen of their country has been assigned there. The first amateur radio call sign assigned to the International Space Station was NA1SS by the United States. OR4ISS (Belgium), DP0ISS (Germany), and RS0ISS (Russia) are examples of others, but are not all-inclusive of others also issued.


title: Call sign

text: Broadcasters are allocated call signs in many countries. While broadcast radio stations will often brand themselves with plain-text names, identities such as "Cool FM", "Rock 105" or "the ABC network" are not globally unique. Another station in another city or country may (and often will) have a similar brand, and the name of a broadcast station for legal purposes is normally its internationally recognised ITU call sign. Some common conventions are followed in each country.


title: Call sign

text: Broadcast stations in North America generally use call signs in the international series. In the United States of America, they are used for all FCC-licensed transmitters. The first letter generally is "K" for stations located west of the Mississippi River and "W" for eastern stations. Historic exceptions in the east include KYW in Philadelphia and KDKA in Pittsburgh, while western exceptions include WJAG in Norfolk, Nebraska, and WOAI in San Antonio. All new call signs have been four-character for some decades, though there are historical three-character call letters still in use today, such as KSL in Salt Lake City, KOA in Denver, WHO in Des Moines, WWJ and WJR in Detroit, WJW-TV in Cleveland, WBT in Charlotte, WBZ in Boston, WSM in Nashville, WGR in Buffalo, KFI, KNX and KHJ in Los Angeles, and WGN, WLS and WLS-TV in Chicago. American radio stations announce their call signs (except for rare cases in which would interfere with the broadcast of very long works of classical or opera music) at the top of each hour, as well as sign-on and sign-off for stations that do not broadcast 24 hours. Beginning in the early 2000s, digital subchannels were assigned a -DT# suffix, where # is the sub channel position (starting with the number 2).


title: Call sign

text: In Canada, the publicly owned Canadian Broadcasting Corporation uses the prefix "CB"; privately owned commercial broadcast stations use primarily "CF" and "CH" through "CK" prefixes; and four stations licensed to St. John's by the Dominion of Newfoundland government retain their original "VO" calls. In Mexico, AM radio stations use "XE" call signs (such as XEW-AM), while the majority of FM radio and television stations use "XH". Broadcast call signs are normally four or five alpha characters in length, plus the "-FM", "-TV", or "-TDT" suffix where applicable.


title: Call sign

text: In South America call signs have been a traditional way of identifying radio and TV stations. Some stations still broadcast their call signs a few times a day, but this practice is becoming very rare. Argentinian broadcast call signs consist of two or three letters followed by multiple numbers, the second and third letters indicating region. In Brazil, radio and TV stations are identified by a ZY, a third letter and three numbers. "ZYA" and "ZYB" are allocated to television stations, "ZYI", "ZYJ", "ZYL" and "ZYK" designate AM stations, "ZYG" is used for shortwave stations, "ZYC", "ZYD", "ZYM" and "ZYU" are given to FM stations.


title: Call sign

text: In Australia, broadcast call signs are optional, but are allocated by the Australian Communications and Media Authority and are unique for each broadcast station.


title: Call sign

text: Most European and Asian countries do not use call signs to identify broadcast stations, but Japan, South Korea, Indonesia, the Philippines and Taiwan do have call sign systems. Spanish broadcasters used call signs consisting of "E" followed by two letters and up to three digits until the late 1970s. Portugal had a similar system, their callsigns beginning with "C"; these also ceased to be used in the 1970s. Britain has no call signs in the American sense, but allows broadcast stations to choose their own trade mark call sign up to six words in length.


title: Call sign

text: Amateur radio call signs are in the international series and normally consist of a one or two character prefix, a digit (which may be used to denote a geographical area, class of license, or identify a licensee as a visitor or temporary resident), and a 1-, 2-, or 3-letter suffix. In Australia, call signs are structured with a two letter prefix, a digit (which identifies geographical area), and a 2, 3 or 4 letter suffix. This suffix may be followed by a further suffix, or personal identifier, such as /P (portable), /M (mobile), /AM (aeronautical mobile) or /MM (maritime mobile). The number following the prefix is normally a single number (0 to 9). Some prefixes, such as Djibouti's (J2), consist of a letter followed by a number. Hence, in the hypothetical Djibouti call sign, J29DBA, the prefix is "J2", the number is "9", and the suffix is "DBA". Others may start with a number followed by a letter, for example, Jamaican call signs begin with 6Y.


title: Call sign

text: When operating with reciprocal agreements under the jurisdiction of a foreign government, an identifying station pre-pends the call sign with the country prefix and number of the country/territory from which the operation is occurring. For example, W4/G3ABC would denote a licensed amateur from the United Kingdom who is operating in the fourth district of the United States. There are exceptions; in the case of U.S./Canadian reciprocal operations, the country/territory identifier is, instead, appended to the call sign; e.g., W1AW/VE4, or VE3XYZ/W1.


title: Call sign

text: Special call signs are issued in the amateur radio service either for special purposes, VIPs, or for temporary use to commemorate special events. Examples include "VO1S" ("VO1" as a Dominion of Newfoundland call sign prefix, "S" to commemorate Marconi's first trans-Atlantic message, a single-character Morse code "S" sent from Cornwall, England to Signal Hill, St. John's in 1901) and GB90MGY ("GB" as a Great Britain call sign prefix, "90" and "MGY" to commemorate the 90th anniversary of historic 1912 radio distress calls from "MGY", the Marconi station aboard the famed White Star luxury liner RMS "Titanic").


title: Call sign

text: The late King Hussein of Jordan was issued a special amateur license number, JY1, which would have been the shortest possible call sign issued by the Hashemite Kingdom of Jordan.


title: Call sign

text: When identifying a station by voice, the call sign may be given by simply stating the letters and numbers, or using a phonetic alphabet. Some countries mandate the use of the phonetic alphabet for identification.


title: Call sign

text: In wartime, monitoring an adversary's communications can be a valuable form of intelligence. Consistent call signs can aid in this monitoring, so in wartime, military units often employ tactical call signs and sometimes change them at regular intervals. In peacetime, some military stations will use fixed call signs in the international series.


title: Call sign

text: The United States Army uses fixed station call signs which begin with "W", such as WAR, used by U.S. Army Headquarters. Fixed call signs for the United States Air Force stations begin with "A", such as AIR, used by USAF Headquarters. The United States Navy, United States Marine Corps, and United States Coast Guard use a mixture of tactical call signs and international call signs beginning with the letter "N".


title: Call sign

text: In the British military, tactical voice communications use a system of call signs of the form "letter-digit-digit". Within a standard infantry battalion, these characters represent companies, platoons and sections respectively, so that 3 Section, 1 Platoon of F Company might be F13. In addition, a suffix following the initial call sign can denote a specific individual or grouping within the designated call sign, so F13C would be the Charlie fire team. Unused suffixes can be used for other call signs that do not fall into the standard call sign matrix, for example the unused 33A call sign is used to refer to the company sergeant major.


title: Call sign

text: No call signs are issued to transmitters of the long-range navigation systems (Decca, Alpha, Omega), or transmitters on frequencies below 10 kHz, because frequencies below 10 kHz are not subject to international regulations. In addition, in some countries lawful unlicensed low-power personal and broadcast radio signals (Citizen's Band(CB), Part 15 or ISM bands) are permitted; an international call sign is not issued to such stations due to their unlicensed nature. Also, wireless network routers or mobile devices and computers using Wi-Fi are unlicensed and do not have call signs. On some personal radio services, such as CB, it is considered a matter of etiquette to create one's own call sign, which is called a handle (or trail name). Some wireless networking protocols also allow SSIDs or MAC addresses to be set as identifiers, but with no guarantee that this label will remain unique. Many mobile telephony systems identify base transceiver stations by implementing cell ID and mobile stations (e.g., phones) by requiring them to authenticate using international mobile subscriber identity (IMSI).


title: Call sign

text: International regulations no longer require a call sign for broadcast stations; however, they are still required for broadcasters in many countries, including the United States. Mobile phone services do not use call signs on-air because the phones and their users are not licensed, instead the cell operator is the one holding the license. However, the U.S. still assigns a call sign to each mobile-phone spectrum license.


title: Call sign

text: In the United States, "voluntary ships" operating domestically are not required to have a call sign or license to operate VHF radios, radar or an EPIRB. Voluntary ships (mostly pleasure and recreational) are not required to have a radio. However, ships which are required to have radio equipment (most large commercial vessels) are issued a call sign.


title: Call sign

text: A directory of radio station call signs is called a callbook. Callbooks were originally bound books that resembled a telephone directory and contained the name and addressees of licensed radio stations in a given jurisdiction (country). Modern Electrics published the first callbook in the United States in 1909.


title: Call sign

text: Today, the primary purpose of a callbook is to allow amateur radio operators to send a confirmation post card, called a QSL card to an operator with whom they have communicated via radio. Callbooks have evolved to include on-line databases that are accessible via the Internet to instantly obtain the address of another amateur radio operator and their QSL Managers. The most well known and used on-line QSL databases include QRZ.COM, IK3QAR, HamCall, F6CYV, DXInfo, OZ7C and QSLInfo.


title: Jerk (physics)

text: In physics, jerk or jolt is the rate at which an object's acceleration changes with respect to time. It is a vector quantity (having both magnitude and direction). Jerk is most commonly denoted by the symbol and expressed in m/s (SI units) or standard gravities per second ("g"/s).


title: Jerk (physics)

text: As a vector, jerk can be expressed as the first time derivative of acceleration, second time derivative of velocity, and third time derivative of position:


title: Jerk (physics)

text: are sometimes called "jerk equations". When converted to an equivalent system of three ordinary first-order non-linear differential equations, jerk equations are the minimal setting for solutions showing chaotic behaviour. This condition generates mathematical interest in "jerk systems". Systems involving fourth-order derivatives or higher are accordingly called "hyperjerk systems".


title: Jerk (physics)

text: Human body position is controlled by balancing the forces of antagonistic muscles. In balancing a given force, such as holding up a weight, the postcentral gyrus establishes a control loop to achieve the desired equilibrium. If the force changes too quickly, the muscles cannot relax or tense fast enough and overshoot in either direction, causing a temporary loss of control. The reaction time for responding to changes in force depends on physiological limitations and the attention level of the brain: an "expected" change will be stabilized faster than a "sudden" decrease or increase of load.


title: Jerk (physics)

text: To avoid vehicle passengers losing control over body motion and getting injured, it is necessary to limit the exposure to both the maximum force (acceleration) "and" maximum jerk, since time is needed to adjust muscle tension and adapt to even limited stress changes. Sudden changes in acceleration can cause injuries such as whiplash. Excessive jerk may also result in an uncomfortable ride, even at levels that do not cause injury. Engineers expend considerable design effort minimizing "jerky motion" on elevators, trams, and other conveyances.


title: Jerk (physics)

text: For a constant mass , acceleration is directly proportional to force according to Newton's second law of motion:


title: Jerk (physics)

text: In classical mechanics of rigid bodies, there are no "forces" associated with the derivatives of acceleration; however, physical systems experience oscillations and deformations as a result of jerk. In designing the Hubble Space Telescope, NASA set limits on both jerk and jounce.


title: Jerk (physics)

text: The Abraham–Lorentz force is the recoil force on an accelerating charged particle emitting radiation. This force is proportional to the particle's jerk and to the square of its charge. The Wheeler–Feynman absorber theory is a more advanced theory, applicable in a relativistic and quantum environment, and accounting for self-energy.


title: Jerk (physics)

text: Discontinuities in acceleration do not occur in real-world environments because of deformation, quantum mechanics effects, and other causes. However, a jump-discontinuity in acceleration and, accordingly, unbounded jerk are feasible in an idealized setting, such as an idealized point mass moving along a piecewise smooth, whole continuous path. The jump-discontinuity occurs at points where the path is not smooth. Extrapolating from these idealized settings, one can qualitatively describe, explain and predict the effects of jerk in real situations.


title: Jerk (physics)

text: Jump-discontinuity in acceleration can be modeled using a Dirac delta function in jerk, scaled to the height of the jump. Integrating jerk over time across the Dirac delta yields the jump-discontinuity.


title: Jerk (physics)

text: For example, consider a path along an arc of radius , which tangentially connects to a straight line. The whole path is continuous, and its pieces are smooth. Now assume a point particle moves with constant speed along this path, so its tangential acceleration is zero. The centripetal acceleration given by is normal to the arc and inward. When the particle passes the connection of pieces, it experiences a jump-discontinuity in acceleration given by , and it undergoes a jerk that can be modeled by a Dirac delta, scaled to the jump-discontinuity.


title: Jerk (physics)

text: For a more tangible example of discontinuous acceleration, consider an ideal spring–mass system with the mass oscillating on an idealized surface with friction. The force on the mass is equal to the vector sum of the spring force and the kinetic frictional force. When the velocity changes sign (at the maximum and minimum displacements), the magnitude of the force on the mass changes by twice the magnitude of the frictional force, because the spring force is continuous and the frictional force reverses direction with velocity. The jump in acceleration equals the force on the mass divided by the mass. That is, each time the mass passes through a minimum or maximum displacement, the mass experiences a discontinuous acceleration, and the jerk contains a Dirac delta until the mass stops. The static friction force adapts to the residual spring force, establishing equilibrium with zero net force and zero velocity.


title: Jerk (physics)

text: Consider the example of a braking and decelerating car. The brake pads generate kinetic frictional forces and constant braking torques on the disks (or drums) of the wheels. Rotational velocity decreases linearly to zero with constant angular deceleration. The frictional force, torque, and car deceleration suddenly reach zero, which indicates a Dirac delta in physical jerk. The Dirac delta is smoothed down by the real environment, the cumulative effects of which are analogous to damping of the physiologically perceived jerk. This example neglects the effects of tire sliding, suspension dipping, real deflection of all ideally rigid mechanisms, etc.


title: Jerk (physics)

text: Another example of significant jerk, analogous to the first example, is the cutting of a rope with a particle on its end. Assume the particle is oscillating in a circular path with non-zero centripetal acceleration. When the rope is cut, the particle's path changes abruptly to a straight path, and the force in the inward direction changes suddenly to zero. Imagine a monomolecular fiber cut by a laser; the particle would experience very high rates of jerk because of the extremely short cutting time.


title: Jerk (physics)

text: Consider a rigid body rotating about a fixed axis in an inertial reference frame. If its angular position as a function of time is , the angular velocity, acceleration, and jerk can be expressed as follows:


title: Jerk (physics)

text: Angular acceleration equals the torque acting on the body, divided by the body's moment of inertia with respect to the momentary axis of rotation. A change in torque results in angular jerk.


title: Jerk (physics)

text: The general case of a rotating rigid body can be modeled using kinematic screw theory, which includes one axial vector, angular velocity , and one polar vector, linear velocity . From this, the angular acceleration is defined as


title: Jerk (physics)

text: For example, consider a Geneva drive, a device used for creating intermittent rotation of a driven wheel (the blue wheel in the animation) by continuous rotation of a driving wheel (the red wheel in the animation). During one cycle of the driving wheel, the driven wheel's angular position changes by 90 degrees and then remains constant. Because of the finite thickness of the driving wheel's fork (the slot for the driving pin), this device generates a discontinuity in the angular acceleration , and an unbounded angular jerk in the driven wheel.


title: Jerk (physics)

text: Jerk does not preclude the Geneva drive from being used in applications such as movie projectors and cams. In movie projectors, the film advances frame-by-frame, but the projector operation has low noise and is highly reliable because of the low film load (only a small section of film weighing a few grams is driven), the moderate speed (2.4 m/s), and the low friction.


title: Jerk (physics)

text: With cam drive systems, use of a dual cam can avoid the jerk of a single cam; however, the dual cam is bulkier and more expensive. The dual-cam system has two cams on one axle that shifts a second axle by a fraction of a revolution. The graphic shows step drives of one-sixth and one-third rotation per one revolution of the driving axle. There is no radial clearance because two arms of the stepped wheel are always in contact with the double cam. Generally, combined contacts may be used to avoid the jerk (and wear and noise) associated with a single follower (such as a single follower gliding along a slot and changing its contact point from one side of the slot to the other can be avoided by using two followers sliding along the same slot, one side each).


title: Jerk (physics)

text: An elastically deformable mass deforms under an applied force (or acceleration); the deformation is a function of its stiffness and the magnitude of the force. If the change in force is slow, the jerk is small, and the propagation of deformation is considered instantaneous as compared to the change in acceleration. The distorted body acts as if it were in a quasistatic regime, and only a changing force (nonzero jerk) can cause propagation of mechanical waves (or electromagnetic waves for a charged particle); therefore, for nonzero to high jerk, a shock wave and its propagation through the body should be considered.


title: Jerk (physics)

text: The propagation of deformation is shown in the graphic "Compression wave patterns" as a compressional plane wave through an elastically deformable material. Also shown, for angular jerk, are the deformation waves propagating in a circular pattern, which causes shear stress and possibly other modes of vibration. The reflection of waves along the boundaries cause constructive interference patterns (not pictured), producing stresses that may exceed the material's limits. The deformation waves may cause vibrations, which can lead to noise, wear, and failure, especially in cases of resonance.


title: Jerk (physics)

text: The graphic captioned "Pole with massive top" shows a block connected to an elastic pole and a massive top. The pole bends when the block accelerates, and when the acceleration stops, the top will oscillate (damped) under the regime of pole stiffness. One could argue that a greater (periodic) jerk might excite a larger amplitude of oscillation because small oscillations are damped before reinforcement by a shock wave. One can also argue that a larger jerk might increase the probability of exciting a resonant mode because the larger wave components of the shock wave have higher frequencies and Fourier coefficients.


title: Jerk (physics)

text: To reduce the amplitude of excited stress waves and vibrations, one can limit jerk by shaping motion and making the acceleration continuous with slopes as flat as possible. Due to limitations of abstract models, algorithms for reducing vibrations include higher derivatives, such as jounce, or suggest continuous regimes for both acceleration and jerk. One concept for limiting jerk is to shape acceleration and deceleration sinusoidally with zero acceleration in between (see graphic captioned "Sinusoidal acceleration profile"), making the speed appear sinusoidal with constant maximum speed. The jerk, however, will remain discontinuous at the points where acceleration enters and leaves the zero phases.


title: Jerk (physics)

text: Roads and tracks are designed to limit the jerk caused by changes in their curvature. On railways, designers use 0.35 m/s as a design goal and 0.5 m/s as a maximum. Track transition curves limit the jerk when transitioning from a straight line to a curve, or vice versa. Recall that in constant-speed motion along an arc, jerk is zero in the tangential direction and nonzero in the inward normal direction. Transition curves gradually increase the curvature and, consequently, the centripetal acceleration.


title: Jerk (physics)

text: An Euler spiral, the theoretically optimum transition curve, linearly increases centripetal acceleration and results in constant jerk (see graphic). In real-world applications, the plane of the track is inclined (cant) along the curved sections. The incline causes vertical acceleration, which is a design consideration for wear on the track and embankment. The Wiener Kurve (Viennese Curve) is a patented curve designed to minimize this wear.


title: Jerk (physics)

text: Rollercoasters are also designed with track transitions to limit jerk. When entering a loop, acceleration values can reach around 4"g" (40 m/s), and riding in this high acceleration environment is only possible with track transitions. S-shaped curves, such as figure eights, also use track transitions for smooth rides.


title: Jerk (physics)

text: In motion control, the design focus is on straight, linear motion, with the need to move a system from one steady position to another (point-to-point motion). The design concern from a jerk perspective is vertical jerk; the jerk from tangential acceleration is effectively zero since linear motion is non-rotational.


title: Jerk (physics)

text: Motion control applications include passenger elevators and machining tools. Limiting vertical jerk is considered essential for elevator riding convenience. ISO 18738 specifies measurement methods for elevator ride quality with respect to jerk, acceleration, vibration, and noise; however, the standard does specify levels for acceptable or unacceptable ride quality. It is reported that most passengers rate a vertical jerk of 2 m/s as acceptable and 6 m/s as intolerable. For hospitals, 0.7 m/s is the recommended limit.