Articles de revues sur le sujet « Muzzle brake »

Blast waves generated from the muzzles of weapons may exert negative effects, such as shock waves and impulse noise. If the weapon is fired with a muzzle brake, these effects are recognized to be more severe. This paper discusses the influence of the muzzle brake on certain aeroacoustic noise characteristics based on numerical simulations and a corresponding experiment. The impulse noise, which is induced by complex jet flows discharging from small caliber rifles with muzzle brakes, is focused in this study. Computational fluid dynamics (CFD) and computational aeroacoustics (CAA) are combined to calculate the muzzle flow field and jet noise for cases with and without a muzzle brake, and then the data sets are carefully compared. The simulations indicate that the muzzle brake alters the muzzle flow field and directional distribution of the jet noise compared to a rifle sans muzzle brake. Deviations less than 7.6% between experimental data and simulation results validate the simulation model. The results presented in this paper may provide a workable reference for the prediction of muzzle noise and the optimization of muzzle brake designs.

The approximate model of the muzzle brake performance was set up and evaluated to simplify the analysis process. LHS(Latin Hypercube Sampling) and numerical simulation of inviscid muzzle flow field were applied to obtain some samples of the muzzle brake performance. The performance was weighted with the impact force on the muzzle brake. Then RSM(Response Surface Method) was adopted to get the approximate model of the muzzle brake performance to establish a mapping of muzzle brake shape parameters and the impact force. In the end GA(Genetic Algorithm) was applied to perform the optimization of the muzzle brake shape parameters with the approximate model.

The development of advanced artillery needs to be combined with simulation means, so, traditional calculation method and the flow field simulation method was employed to calculate the efficiency of a largecaliber muzzle brake we designed, and the results achieved by these two methods were 47.8% and 49.3%, respectively. Further, the overpressure value 1 m away from the muzzle was obtained through flow field simulation, and the far-field overpressure value was calculated using blast wave attenuation equations. The result suggests that the blast wave from the designed muzzle brake has little harmful impact. This paper provides an intuitive calculation method of muzzle brake efficiency, also, it provides theoretical support for research of high efficiency muzzle brake and personnel protection onboard.

In order to reduce the recoil energy of the chain gun, this paper put forward a high-efficiency recoil-reducing way with new-style high-efficiency muzzle brake and buffer parameter combined by studying the modeling and simulation of low recoil firing of chain gun. This paper studied the variation rules of gun recoil movement and recoil force of muzzle brake on three states. The results show the recoil of chain gun can be reduced significantly by using high-efficiency muzzle brake and selecting suitable parameters for buffer compared with that of only using muzzle brake and buffer. The research results put forward theoretical basis and application reference for studying high power low recoil chain gun.

Gunpowder was released in an instant when the pill fly out of the shell during the firing, and then formed a complicated flow fields about the muzzle when the gas expanded sharply. Using the 2 d axisymmetric Navier-Stokes equation combined with single equation turbulent model to conduct the numerical simulation of the process of gunpowder gass evacuating out of the shell without muzzle regardless of the pill’s movement. The numerical simulation result was identical with the experimental. Then simulated the evacuating process of gunpowder gass of an artillery with muzzle brake. The result showed complicated wave structure of the flow fields with the muzzle brake and analysed the influence of muzzle brake to the gass flow field distribution.

This paper discusses characteristics of supersonic projectile shock wave in muzzle regions when firing high explosive anti-tank (HEAT) and high explosive (HE) projectiles. They are fired with a muzzle velocity of Mach 3.5 at horizontal from a medium caliber tank gun equipped with a new designed multi-perforated muzzle brake and of Mach 2 at elevation angles from a large caliber howitzer also equipped with a new double baffles muzzle brake, respectively. In the near field, pressure signatures of the N-wave generated from projectiles are measured by cotton sheathed 32-microphone ring array. Recordings measured from the microphone array are used to demonstrate several key characteristics of the shock wave of supersonic projectile. All measurements in this study can be a significant reference for developing guns, tanks or the chassis of fighting vehicles.

A modern tank gun for light vehicles should be light in weight and have a low recoil force. Therefore it needs an integrated muzzle brake that, however, reduces the strength in the muzzle area. The loading due to gas pressure in this area is as fast as the projectile, and some dynamical effects like traveling waves have to be taken into account. The analytical solution of traveling waves for a smooth tube will be explained on the basis of the shell theory for thin shells. The solution leads to a deeper understanding of the nature of these waves than a pure numerical solution. Since tubes are not really thin, even in the muzzle area, the error that may occur when applying the shell theory is estimated. The analytical solution will be compared to some finite element solutions, which include a multiperforated muzzle brake with a cover tube. The results give some useful hints to the interaction between gas pressure, projectile velocity, and wall thickness and help to reduce the weight of the barrel.

Muzzle brakes (MBs) have a great effect on reducing the recoil force of weapons during firing. In this paper, optimum MB efficiency, MB force and recoil force for (12,7 x 99 mm) sniper rifle have been studied. The objective is to obtain the optimum area of side openings, inclination angle and number of chambers for the MB in order to increase the MB efficiency and MB force and thereby to decrease their coil force of the weapon. An analytical model for calculating MB efficiency, MB force and weapon recoil force for MBs of two, three and four chambers has been established. This Model is then utilised in combination with design of experiment (DOE) and Response Surface Method (RSM) statistical techniques to develop a smooth response function which can be efficiently used in optimisation formulation. Finally, multi objectives generic algorithm (MOGA) optimisation method has been employed to find the optimum MB design parameters. The optimisation results show that the three or four chambers MBs have no significant effect on reducing the weapon recoil force compared with the two chamber MB for this sniper rifle.

The recoil from an electromagnetic (EM) railgun is discussed and compared with that from conventional, propellant gas driven cannon. It is shown that, under similar launch conditions, the recoil of the EM gun is less than that of the powder gun; however, use of a muzzle brake on a powder gun can alter this relative behavior.

In the paper a concept of internal support of remote operated weapon station mounts on civil vehicle Toyota Landcruiser L200 was presented. The support was placed inside the standard vehicle structure. The geometry of internal surfaces of structured was resembled with the use of 3D laser scanner. Designed additional support structure was used to simulate the impulsive load by shooting 12.7 machine gun equipped with muzzle brake. Results of simulation were presented and discussed.

A phenomenon that is present in almost every shot is highlighted. It manifests itself in the muzzle discharge as a certain amount of free carbon. The thermochemical reaction of Boudouard-Bell (disproportionation of carbon monoxide) was determined, which explains the formation of free carbon in the gunpowder gases during the firing process. A feature of this reaction is the formation of a condensed phase of carbon during the firing process after the gasification of the gunpowder charge. The reason is revealed that does not allow describing the formation of free carbon during firing on the basis of existing models of internal ballistics processes. It is the lack of taking into account the temperature distribution of the gunpowder gases along the length of the gun barrel and its change. A mathematical model is proposed that makes it possible to estimate the temperature distribution during the shot. A method has been developed for solving the problem of internal ballistics with the ability to determine the temperature of gunpowder gases along the length of the gun barrel at different times and at different positions of the projectile in the barrel. The original model is built using generally accepted assumptions. Modeling results can only be estimated. For this reason, the method is based on simple calculations, which makes it possible not to involve high-power computing equipment. The modeling of the temperature distribution of gunpowder gases in the space of the gun barrel between the charging ball and the moving projectile in the model system is carried out. The possibility of changing the length of the zone of the Boudouard-Bell reaction (the zone of formation of free carbon) depending on the initial data is shown. The use of a fresh gunpowder charge and a degraded one is simulated. Full and reduced charges are considered. The simulation results showed the reason for the possibility of initiating a secondary muzzle discharge flash both from the front side and from the side of the muzzle brake.

In the United States and other parts of the world, recreational firearm shooting is a popular sport that puts the hearing of the shooter at risk. Peak sound pressure levels (SPLs) from firearms range from ∼140 to 175 dB. The majority of recreational firearms (excluding small-caliber 0.17 and 0.22 rifles and air rifles) generate between 150 and 165 dB peak SPLs. High-intensity impulse sounds will permanently damage delicate cochlear structures, and thus individuals who shoot firearms are at a higher risk of bilateral, high-frequency, noise-induced hearing loss (NIHL) than peer groups who do not shoot. In this article, we describe several factors that influence the risk of NIHL including the use of a muzzle brake, the number of shots fired, the distance between shooters, the shooting environment, the choice of ammunition, the use of a suppressor, and hearing protection fit and use. Prevention strategies that address these factors and recommendations for specialized hearing protectors designed for shooting sports are offered. Partnerships are needed between the hearing health community, shooting sport groups, and wildlife conservation organizations to develop and disseminate accurate information and promote organizational resources that support hearing loss prevention efforts.

The measurement of recoil distance versus time by various methods such as the recoil potentiometer, photo electric transducer, slide wire, accelerometer, revolving drum system, and linear variable differential transformer (LVDT) has been used for gross muzzle brake efficiency measurements and recoil system performance evaluation by the calculation of recoil velocities. For a long recoil-length gun system, a combination of recoil potentiometer and LVDT is used extensively. In order to dispense with the use of recoil potentiometer in the above combination, the article proposes the use of the least-square-fit-based Richardson's extrapolation method and mean square velocity calculation for the accurate determination of free recoil velocity. The mean square velocity calculation is based on Parseval's theorem. The proposed method is based on the comparative evaluation of second- and third-order finite difference method, Richardson's fourth-order method, and the least-square-fit-based Richardson's extrapolation. The least-square-fit-based Richardson's extrapolation gives the lowest value of residual entropy. This is because the maximum likelihood estimators for Gauss probability distribution function and least-square estimators for the coefficients of polynomial representing recoil velocity time curve are coincident. The results of each of the four methods combined with the mean square velocity method were compared, and the least-square-fit-based Richardson's extrapolation was found to be accurate and consistent. The method can be used even when low pass filter is included in the LVDT circuit for stand-alone use.

Twórczość Romana Palestra dla filmu odcisnęła trwały ślad w dziejach polskiej kinematografii, mimo iż sam kompozytor nie nadawał temu aspektowi swej działalności większej wagi. Niniejszy artykuł poświęcony jest pierwszej (do 1939 roku) fazie pracy kompozytora na rzecz filmu. Celem jest, dokonana na podstawie zachowanych materiałów audiowizualnych i źródeł pośrednich, próba zarysowania panoramy recepcji filmowej muzyki Palestra w międzywojennym środowisku kulturowym, określenia zasad jego współpracy z innymi kompozytorami w przypadku współautorstwa, a także syntetyczna charakterystyka funkcji, znaczenia i własności ścieżek dźwiękowych Palestra ze szczególnym uwzględnieniem filmu pt. Zabawka. Najefektywniejszą współpracę nawiązał Palester z reżyserem Józefem Lejtesem (1901–1983). Napisał muzykę do pięciu jego filmów (Dzikie pola, 1932; Młody las, 1934; Dzień wielkiej przygody, 1935; Róża, 1936 oraz Dziewczęta z Nowolipek, 1937), przy czym każdorazowo partnerem Palestra w realizacji tego zadania był Marian Neuteich. Z Neuteichem współtworzył Palester także muzykę do Ludzi Wisły (1938) Aleksandra Forda i Aleksandra Zarzyckiego. Z kolei przy muzyce do filmu August Mocny (1936) współpracował z Leonem Schillerem, a przy opracowaniu muzycznym Halki opartej na kanwie libretta opery Stanisława Moniuszki współdziałał z Feliksem Rybickim. Współautorskim dziełem jest także ilustracja muzyczna do filmu Ja tu rządzę (1939) dokonana wespół z Władysławem Danem. Wobec braku partytur i ogólnego charakteru informacji wnoszonych przez napisy do filmów trudno z pewnością stwierdzić, jak wyglądał rzeczywisty podział ról i kompetencji w tych kompozytorskich tandemach. Niewątpliwie jednak (z wyjątkiem ostatniego z wymienionych filmów) wykraczał on poza prostą dwuzadaniowość: muzyka „lekka” versus „poważna”. Ponadto w filmach Lejtesa ilustracja muzyczna wpisuje się w reżyserską koncepcję kojarzenia niezależnych od siebie elementów dźwiękowych i wizualnych w tzw. „trzeci wymiar” i uwikłana jest w liczne konteksty symboliczne. Samodzielnymi ilustracjami muzycznymi Palestra są te do filmu Zabawka (1933) Michała Waszyńskiego oraz dwóch produkcji z 1939 roku – Żołnierza Królowej Madagaskaru Jerzego Zarzyckiego i Nad Niemnem Wandy Jakubowskiej i Karola Szołowskiego, które nie zachowały się do dnia dzisiejszego. Muzyka do Zabawki stanowi kunsztowny przykład konstytutywnego wykorzystania popularnych piosenek w funkcji dramaturgicznie integrującej oraz łączenia tego materiału z muzyką utrzymaną w powszechnym stylu komponowania do wczesnego kina dźwiękowego. Dopełnieniem działalności filmowej Palestra do 1939 roku jest – wedle istniejących opracowań badawczych – muzyka do dwóch filmów dokumentalnych, choć jest to obszar możliwy do uzupełnienia. Cały omówiony tu jego dorobek świadczy zaś o z jednej strony o zdystansowanym, a z drugiej pełnym rzetelności i warsztatowej sprawności stosunku Palestra do zamówień na muzykę filmową. Prace te stanowią nieusuwalną i niewątpliwie wartą przybliżenia część twórczego wizerunku tego kompozytora.

During a gun firing, the flow around a projectile will be developing and changing. In particular, the flow around the projectile is disturbed significantly when the projectile overtakes the muzzle flow. Furthermore, the projectile body pressure will also change substantially. Therefore, the shot ejection process has an important effect on the shot accuracy. The maximum projectile velocity is one of the most important design goals of the interior ballistic process and also is the initial condition for the exterior ballistic process. Most researchers take the muzzle velocity as the maximum projectile velocity; actually, after the projectile exits the muzzle, the projectile velocity will increase further due to the influence of the muzzle flow. Most investigations of the muzzle flow focused on the blowout of the high-pressure jet flow after the projectile exited the muzzle. The interior ballistic process was ignored or simply assumed in most investigations. Also, the mutual influence between the moving projectile and the muzzle flow was often neglected. Actually, a precursor shock flow near the muzzle is formed before the projectile exits. This precursor muzzle flow has an important influence on the trajectory of the projectile, especially, for the prevalent trend of gun systems including large caliber cannon and multiple launch gun systems. For these reasons, the interior ballistic process was coupled with the simulation of the flow near the muzzle. A hybrid structured-unstructured gridding method was used to simulate the process from the projectile engraving to the gas ejection phase, accounting for the moving projectile. The simulation results show that the projectile muzzle velocity was 893.99 m/s but the maximum velocity was 899.28 m/s. The projectile velocity increased rapidly to up to 0.8 ms after muzzle exit; thereafter, the projectile velocity increased slowly before reaching its maximum value. The maximum Mach number of the effluent gas increased to 6.83 and the breech pressure decreased to 21.5 MPa at 1.8 ms after the projectile exited the muzzle. The formation and development of the muzzle flow field was highly complex and transient. The analysis of the projectile velocity was conducted during the interior ballistic after-effect period. The predicted muzzle velocity and maximum barrel pressure are in good agreement with those measured in gun firings. Results of the numerical simulation and analysis are helpful to understand and master the aerodynamic process of gun system launching and provide significant guidance for research into shot accuracy and muzzle brake design.

For several years we have been working on the development of a computational fluid dynamics ballistics code called FREIN. This code is the result of a strong cooperation between Nexter Munitions and the University of Poitiers. In the last years, efforts have been carried out to improve the 3D modeling. In a fully unsteady way, the interior, intermediate and exterior ballistics were modeled as well as the weapon system environment. The complex phenomena encountered are investigated by an adapted numerical simulation approach using the Euler equations for two immiscible gases. The method involves moving bodies with respect to fixed Cartesian meshes and the aerodynamic forces are used to compute the trajectories. In this paper, theoretical developments and computations have been applied mainly to the simulation of the firing of an advanced 120 mm lightweight tank demonstrator. In comparison with firing experiments, first computation validation results concerning interior ballistics, muzzle brake flow, sabot discard and blast wave propagation and reflection are presented and are very satisfactory.

Firearms Use Comes With A Number Of Potential Health & Environmental Hazards Due To The High Noise Levels Generated. Noise Reduction Is Clearly A Desirable Goal. Firearm Silencers Are Often More Correctly Referred To As Sound Suppressors, Sound Moderators, Or Mufflers In The Interests Of Consistency With Federal Legislation, The Term Ilencershall Be Used Throughout This Paper. Firearm Silencers Are Legal For Civilian Ownership And Use In The Majority Of Us States, Though They Are Heavily Regulated. In States Where Silencers Are Legal Their Regulation Is Typically Accomplished At The Federal Level, Though Many States Do Have Their Own Laws. This Paper Focuses On Federal Legislation And Its Administration, Enforcement, And Litigation. Until 1934 There Were No Restrictions On Silencer Ownership And Use By Private Individuals. In 1934 Congress Passed The National Firearms Act (Nfa) Which Had The Net Effect Of Making Silencer Manufacture, And Possession By Private Citizens, A Prohibitively Costly And Administratively Burdensome Endeavor. The Nfa Legislation Is Articulated In Title 26 Of The United States Code, And The Federal Law Is Administered And Enforced By The Us Department Of Justice (Doj) Via The Bureau Of Alcohol, Tobacco, Firearms, And Explosives (Batfe). Commercially Available Silencers Reduce The Muzzle Report Of A Firearm By Reducing Peak Sound Pressure By 30 To 40 Decibels (Db). A 223 Remington (5.56mm Nato) Caliber Rifle Will Typically Generate Around 160 Db Without A Silencer, And Just 120 To 130 Db With A Typical Commercially Available Silencer Installed. Some Individuals Construct Homemade Silencers, With Varying Degrees Of Success. Federal Prosecutors, Possibly Prompted By An Overzealous Batfe, And Following The Letter Of The Law, Feel Justified In Prosecuting Cases Where The Alleged Silencer Reduces The Noise Generated By Just A Few Db. The Law Defines, In Part, A Silencer, Or Muffler, As Ny Device For Silencing, Muffling, Or Diminishing The Report Of A Portable Firearm This Is A Very Vague Definition, And In Strict Technical Terms It Could Include Legitimate Technologies, Such As A Lengthened Barrel, A Muzzle Brake, Or A Flash Hider, All Of Which Will Diminish, Or Redirect, The Noise Of A Gunshot. Understanding Sound, And Sound Measurement, Is Not Easy, And This Fact Coupled With The Loose Legal Definition Of What Constitutes A Silencer Leads To The Prosecution Of Many Individuals Who, Either Deliberately Or Inadvertently, Have Procured Or Created A Device For Their Firearm That Reduces The Measured Report By Only A Small Amount. A Study Published By The American Medical Association1 Revealed That Recreational Shooters Suffered Hearing Damage Following Very Limited Exposure To Firearms Noise, And That Damage Occurred Even When Shooters Wore Hearing Protection. Paradoxically, In An Age When Both Legislators, And The Population At Large, Are Obsessed With Environmental And Health & Safety Issues, We Have Outdated Legislation In Place That Actually Works To Make An Everyday Item Less Safe For The User, And Less Environmentally Friendly From The Perspective Of Those In The Vicinity Of The User. We Have Legislation That Seeks To Limit The Noise Produced By Motorcycles And Other Motor Vehicles While, Concurrently, We Have Legislation That Makes It Illegal (Or Prohibitively Burdensome & Expensive) To Attempt To Reduce The Dangerous Noise Produced By Firearms. The Injustices And Difficulties Resulting From Poorly Drafted Legislation Have Been Compounded By The Use Of Outdated Batfe Testing Protocols. To Their Credit, Batfe Appear To Have Been Receptive To The Use Of New Technology And Things Have Improved Somewhat In Recent Years. Sound Measuring Equipment With A Data Sample Time Interval Short Enough To Accurately Capture A Gunshot Is Expensive, And Interpretation Of Results Is Difficult For Those Not Well Versed In The Technical Intricacies Of Acoustics. This Paper Includes Two Case Studies. The First Case Study Demonstrates How Outdated Test Protocols And Inappropriate Equipment Lead To Potentially Misleading Results. The Second Case Study Demonstrates How An Overzealous Prosecution Expert Can Paint A Misleading Picture Of An Alleged Homemade Silencer. It Is Concluded That Current Legislation Relating To Silencers Provides Vague Technical Definitions, Leads To Unnecessary And Expensive Prosecutions, Has A Significant Adverse Affect On The Health Of The Nation, And Raises Significant Legal, Administrative, And Financial Barriers To Those Firearms Owners Who Wish To Maximize Safety And Minimize Environmental Impact.

Being a celebrity sure ain’t what it used to be. Or, perhaps more accurately, the process of maintaining a stable star persona isn’t what it used to be. With the rise of new media technologies—including digital photography and video production, gossip blogging, social networking sites, and streaming video—there has been a rapid proliferation of voices which serve to articulate stars’ personae. This panoply of sanctioned and unsanctioned discourses has brought the coherence and stability of the star’s image into crisis, with an evermore-heightened loop forming recursively between celebrity gossip and scandals, on the one hand, and, on the other, new media-enabled speculation and commentary about these scandals and gossip-pieces. Of course, while no subject has a single meaning, Hollywood has historically expended great energy and resources to perpetuate the myth that the star’s image is univocal. In the present moment, however, studios’s traditional methods for discursive control have faltered, such that celebrities have found it necessary to take matters into their own hands, using new media technologies, particularly Twitter, in an attempt to stabilise that most vital currency of their trade, their professional/public persona. In order to fully appreciate the significance of this new mode of publicity management, and its larger implications for contemporary subjectivity writ large, we must first come to understand the history of Hollywood’s approach to celebrity publicity and image management.A Brief History of Hollywood PublicityThe origins of this effort are nearly as old as Hollywood itself, for, as Richard DeCordova explains, the celebrity scandals of the 1920s threatened to disrupt the economic vitality of the incipient industry such that strict, centralised image control appeared as a necessary imperative to maintain a consistently reliable product. The Fatty Arbuckle murder trial was scandalous not only for its subject matter (a murder suffused with illicit and shadowy sexual innuendo) but also because the event revealed that stars, despite their mediated larger-than-life images, were not only as human as the rest of us, but that, in fact, they were capable of profoundly inhuman acts. The scandal, then, was not so much Arbuckle’s crime, but the negative pall it cast over the Hollywood mythos of glamour and grace. The studios quickly organised an industry-wide regulatory agency (the MPPDA) to counter potentially damaging rhetoric and ward off government intervention. Censorship codes and morality clauses were combined with well-funded publicity departments in an effort that successfully shifted the locus of the star’s extra-filmic discursive construction from private acts—which could betray their screen image—to information which served to extend and enhance the star’s pre-existing persona. In this way, the sanctioned celebrity knowledge sphere became co-extensive with that of commercial culture itself; the star became meaningful only by knowing how she spent her leisure time and the type of make-up she used. The star’s identity was not found via unsanctioned intrusion, but through studio-sanctioned disclosure, made available in the form of gossip columns, newsreels, and fan magazines. This period of relative stability for the star's star image was ultimately quite brief, however, as the collapse of the studio system in the late 1940s and the introduction of television brought about a radical, but gradual, reordering of the star's signifying potential. The studios no longer had the resources or incentive to tightly police star images—the classic age of stardom was over. During this period of change, an influx of alternative voices and publications filled the discursive void left by the demise of the studios’s regimented publicity efforts, with many of these new outlets reengaging older methods of intrusion to generate a regular rhythm of vendible information about the stars.The first to exploit and capitalize on star image instability was Robert Harrison, whose Confidential Magazine became the leading gossip publication of the 1950s. Unlike its fan magazine rivals, which persisted in portraying the stars as morally upright and wholesome, Confidential pledged on the cover of each issue to “tell the facts and name the names,” revealing what had been theretofore “confidential.” In essence, through intrusion, Confidential reasserted scandal as the true core of the star, simultaneously instituting incursion and surveillance as the most direct avenue to the “kernel” of the celebrity subject, obtaining stories through associations with call girls, out-of-work starlettes, and private eyes. As extra-textual discourses proliferated and fragmented, the contexts in which the public encountered the star changed as well. Theatre attendance dropped dramatically, and as the studios sold their film libraries to television, the stars, formerly available only on the big screen and in glamour shots, were now intercut with commercials, broadcast on grainy sets in the domestic space. The integrity—or at least the illusion of integrity—of the star image was forever compromised. As the parameters of renown continued to expand, film stars, formally distinguished from all other performers, migrated to television. The landscape of stardom was re-contoured into the “celebrity sphere,” a space that includes television hosts, musicians, royals, and charismatic politicians. The revamped celebrity “game” was complex, but still playabout: with a powerful agent, a talented publicist, and a check on drinking, drug use, and extra-marital affairs, a star and his or her management team could negotiate a coherent image. Confidential was gone, The National Inquirer was muzzled by libel laws, and People and E.T.—both sheltered within larger media companies—towed the publicists’s line. There were few widely circulated outlets through which unauthorised voices could gain traction. Old-School Stars and New Media Technologies: The Case of Tom CruiseYet with the relentless arrival of various news media technologies beginning in the 1980s and continuing through the present, maintaining tight celebrity image control began to require the services of a phalanx of publicists and handlers. Here, the example of Tom Cruise is instructive: for nearly twenty years, Cruise’s publicity was managed by Pat Kingsley, who exercised exacting control over the star’s image. With the help of seemingly diverse yet essentially similar starring roles, Cruise solidified his image as the cocky, charismatic boy-next-door.The unified Cruise image was made possible by shutting down competing discourses through the relentless, comprehensive efforts of his management company; Kingsley's staff fine-tuned Cruise’s acts of disclosure while simultaneously eliminating the potential for unplanned intrusions, neutralising any potential scandal at its source. Kingsley and her aides performed for Cruise all the functions of a studio publicity department from Hollywood’s Golden Age. Most importantly, Cruise was kept silent on the topic of his controversial religion, Scientology, lest it incite domestic and international backlash. In interviews and off-the-cuff soundbites, Cruise was ostensibly disclosing his true self, and that self remained the dominant reading of what, and who, Cruise “was.” Yet in 2004, Cruise fired Kingsley, replaced her with his own sister (and fellow Scientologist), who had no prior experience in public relations. In essence, he exchanged a handler who understood how to shape star disclosure for one who did not. The events that followed have been widely rehearsed: Cruise avidly pursued Katie Holmes; Cruise jumped for joy on Oprah’s couch; Cruise denounced psychology during a heated debate with Matt Lauer on The Today Show. His attempt at disclosing this new, un-publicist-mediated self became scandalous in and of itself. Cruise’s dismissal of Kingsley, his unpopular (but not necessarily unwelcome) disclosures, and his own massively unchecked ego all played crucial roles in the fall of the Cruise image. While these stumbles might have caused some minor career turmoil in the past, the hyper-echoic, spastically recombinatory logic of the technoculture brought the speed and stakes of these missteps to a new level; one of the hallmarks of the postmodern condition has been not merely an increasing textual self-reflexivity, but a qualitative new leap forward in inter-textual reflexivity, as well (Lyotard; Baudrillard). Indeed, the swift dismantling of Cruise’s long-established image is directly linked to the immediacy and speed of the Internet, digital photography, and the gossip blog, as the reflexivity of new media rendered the safe division between disclosure and intrusion untenable. His couchjumping was turned into a dance remix and circulated on YouTube; Mission Impossible 3 boycotts were organised through a number of different Web forums; gossip bloggers speculated that Cruise had impregnated Holmes using the frozen sperm of Scientology founder L. Ron Hubbard. In the past, Cruise simply filed defamation suits against print publications that would deign to sully his image. Yet the sheer number of sites and voices reproducing this new set of rumors made such a strategy untenable. Ultimately, intrusions into Cruise’s personal life, including the leak of videos intended solely for Scientology recruitment use, had far more traction than any sanctioned Cruise soundbite. Cruise’s image emerged as a hollowed husk of its former self; the sheer amount of material circulating rendered all attempts at P.R., including a Vanity Fair cover story and “reveal” of daughter Suri, ridiculous. His image was fragmented and re-collected into an altered, almost uncanny new iteration. Following the lackluster performance of Mission Impossible 3 and public condemnation by Paramount head Sumner Redstone, Cruise seemed almost pitiable. The New Logic of Celebrity Image ManagementCruise’s travails are expressive of a deeper development which has occurred over the course of the last decade, as the massively proliferating new forms of celebrity discourse (e.g., paparazzi photos, mug shots, cell phone video have further decentered any shiny, polished version of a star. With older forms of media increasingly reorganising themselves according to the aesthetics and logic of new media forms (e.g., CNN featuring regular segments in which it focuses its network cameras upon a computer screen displaying the CNN website), we are only more prone to appreciate “low media” forms of star discourse—reports from fans on discussion boards, photos taken on cell phones—as valid components of the celebrity image. People and E.T. still attract millions, but they are rapidly ceding control of the celebrity industry to their ugly, offensive stepbrothers: TMZ, Us Weekly, and dozens of gossip blogs. Importantly, a publicist may be able to induce a blogger to cover their client, but they cannot convince him to drop a story: if TMZ doesn’t post it, then Perez Hilton certainly will. With TMZ unabashedly offering pay-outs to informants—including those in law enforcement and health care, despite recently passed legislation—a star is never safe. If he or she misbehaves, someone, professional or amateur, will provide coverage. Scandal becomes normalised, and, in so doing, can no longer really function as scandal as such; in an age of around-the-clock news cycles and celebrity-fixated journalism, the only truly scandalising event would be the complete absence of any scandalous reports. Or, as aesthetic theorist Jacques Ranciere puts it; “The complaint is then no longer that images conceal secrets which are no longer such to anyone, but, on the contrary, that they no longer hide anything” (22).These seemingly paradoxical involutions of post-modern celebrity epistemologies are at the core of the current crisis of celebrity, and, subsequently, of celebrities’s attempts to “take back their own paparazzi.” As one might expect, contemporary celebrities have attempted to counter these new logics and strategies of intrusion through a heightened commitment to disclosure, principally through the social networking capabilities of Twitter. Yet, as we will see, not only have the epistemological reorderings of postmodernist technoculture affected the logic of scandal/intrusion, but so too have they radically altered the workings of intrusion’s dialectical counterpart, disclosure.In the 1930s, when written letters were still the primary medium for intimate communication, stars would send lengthy “hand-written” letters to members of their fan club. Of course, such letters were generally not written by the stars themselves, but handwriting—and a star’s signature—signified authenticity. This ritualised process conferred an “aura” of authenticity upon the object of exchange precisely because of its static, recurring nature—exchange of fan mail was conventionally understood to be the primary medium for personal encounters with a celebrity. Within the overall political economy of the studio system, the medium of the hand-written letter functioned to unleash the productive power of authenticity, offering an illusion of communion which, in fact, served to underscore the gulf between the celebrity’s extraordinary nature and the ordinary lives of those who wrote to them. Yet the criterion and conventions through which celebrity personae were maintained were subject to change over time, as new communications technologies, new modes of Hollywood's industrial organization, and the changing realities of commercial media structures all combined to create a constantly moving ground upon which the celebrity tried to affix. The celebrity’s changing conditions are not unique to them alone; rather, they are a highly visible bellwether of changes which are more fundamentally occurring at all levels of culture and subjectivity. Indeed, more than seventy years ago, Walter Benjamin observed that when hand-made expressions of individuality were superseded by mechanical methods of production, aesthetic criteria (among other things) also underwent change, rendering notions of authenticity increasingly indeterminate.Such is the case that in today’s world, hand-written letters seem more contrived or disingenuous than Danny DeVito’s inaugural post to his Twitter account: “I just joined Twitter! I don't really get this site or how it works. My nuts are on fire.” The performative gesture in DeVito’s tweet is eminently clear, just as the semantic value is patently false: clearly DeVito understands “this site,” as he has successfully used it to extend his irreverent funny-little-man persona to the new medium. While the truth claims of his Tweet may be false, its functional purpose—both effacing and reifying the extraordinary/ordinary distinction of celebrity and maintaining DeVito’s celebrity personality as one with which people might identify—is nevertheless seemingly intact, and thus mirrors the instrumental value of celebrity disclosure as performed in older media forms. Twitter and Contemporary TechnocultureFor these reasons and more, considered within the larger context of contemporary popular culture, celebrity tweeting has been equated with the assertion of the authentic celebrity voice; celebrity tweets are regularly cited in newspaper articles and blogs as “official” statements from the celebrity him/herself. With so many mediated voices attempting to “speak” the meaning of the star, the Twitter account emerges as the privileged channel to the star him/herself. Yet the seemingly easy discursive associations of Twitter and authenticity are in fact ideological acts par excellence, as fixations on the indexical truth-value of Twitter are not merely missing the point, but actively distracting from the real issues surrounding the unsteady discursive construction of contemporary celebrity and the “celebretification” of contemporary subjectivity writ large. In other words, while it is taken as axiomatic that the “message” of celebrity Twittering is, as Henry Jenkins suggests, “Here I Am,” this outward epistemological certainty veils the deeply unstable nature of celebrity—and by extension, subjectivity itself—in our networked society.If we understand the relationship between publicity and technoculture to work as Zizek-inspired cultural theorist Jodi Dean suggests, then technologies “believe for us, accessing information even if we cannot” (40), such that technology itself is enlisted to serve the function of ideology, the process by which a culture naturalises itself and attempts to render the notion of totality coherent. For Dean, the psycho-ideological reality of contemporary culture is predicated upon the notion of an ever-elusive “secret,” which promises to reveal us all as part of a unitary public. The reality—that there is no such cohesive collective body—is obscured in the secret’s mystifying function which renders as “a contingent gap what is really the fact of the fundamental split, antagonism, and rupture of politics” (40). Under the ascendancy of the technoculture—Dean's term for the technologically mediated landscape of contemporary communicative capitalism—subjectivity becomes interpellated along an axis blind to the secret of this fundamental rupture. The two interwoven poles of this axis are not unlike structuralist film critics' dialectically intertwined accounts of the scopophilia and scopophobia of viewing relations, simply enlarged from the limited realm of the gaze to encompass the entire range of subjectivity. As such, the conspiratorial mindset is that mode of desire, of lack, which attempts to attain the “secret,” while the celebrity subject is that element of excess without which desire is unthinkable. As one might expect, the paparazzi and gossip sites’s strategies of intrusion have historically operated primarily through the conspiratorial mindset, with endless conjecture about what is “really happening” behind the scenes. Under the intrusive/conspiratorial paradigm, the authentic celebrity subject is always just out of reach—a chance sighting only serves to reinscribe the need for the next encounter where, it is believed, all will become known. Under such conditions, the conspiratorial mindset of the paparazzi is put into overdrive: because the star can never be “fully” known, there can never be enough information about a star, therefore, more information is always needed. Against this relentless intrusion, the celebrity—whose discursive stability, given the constant imperative for newness in commercial culture, is always in danger—risks a semiotic liquidation that will totally displace his celebrity status as such. Disclosure, e.g. Tweeting, emerges as a possible corrective to the endlessly associative logic of the paparazzi’s conspiratorial indset. In other words, through Twitter, the celebrity seeks to arrest meaning—fixing it in place around their own seemingly coherent narrativisation. The publicist’s new task, then, is to convincingly counter such unsanctioned, intrusive, surveillance-based discourse. Stars continue to give interviews, of course, and many regularly pose as “authors” of their own homepages and blogs. Yet as posited above, Twitter has emerged as the most salient means of generating “authentic” celebrity disclosure, simultaneously countering the efforts of the papparazzi, fan mags, and gossip blogs to complicate or rewrite the meaning of the star. The star uses the account—verified, by Twitter, as the “real” star—both as a means to disclose their true interior state of being and to counter erastz narratives circulating about them. Twitter’s appeal for both celebrities and their followers comes from the ostensible spontaneity of the tweets, as the seemingly unrehearsed quality of the communiqués lends the form an immediacy and casualness unmatched by blogs or official websites; the semantic informality typically employed in the medium obscures their larger professional significance for celebrity tweeters. While Twitter’s air of extemporary intimacy is also offered by other social networking platforms, such as MySpace or Facebook, the latter’s opportunities for public feedback (via wall-posts and the like) works counter to the tight image control offered by Twitter’s broadcast-esque model. Additionally, because of the uncertain nature of the tweet release cycle—has Ashton Kutcher sent a new tweet yet?—the voyeuristic nature of the tweet disclosure (with its real-time nature offering a level of synchronic intimacy that letters never could have matched), and the semantically displaced nature of the medium, it is a form of disclosure perfectly attuned to the conspiratorial mindset of the technoculture. As mentioned above, however, the conspiratorial mindset is an unstable subjectivity, insofar as it only exists through a constant oscillation with its twin, the celebrity subjectivity. While we can understand that, for the celebrities, Twitter functions by allowing them a mode for disclosive/celebrity subjectivisation, we have not yet seen how the celebrity itself is rendered conspiratorial through Twitter. Similarly, only the conspiratorial mode of the follower’s subjectivity has thus far been enumerated; the moment of the follower's celebrtification has so far gone unmentioned. Since we have seen that the celebrity function of Twitter is not really about discourse per se, we should instead understand that the ideological value of Twitter comes from the act of tweeting itself, of finding pleasure in being engaged in a techno-social system in which one's participation is recognised. Recognition and participation should be qualified, though, as it is not the fully active type of participation one might expect in say, the electoral politics of a representative democracy. Instead, it is a participation in a sort of epistemological viewing relations, or, as Jodi Dean describes it, “that we understand ourselves as known is what makes us think there is that there is a public that knows us” (122). The fans’ recognition by the celebrity—the way in which they understood themselves as known by the star was once the receipt of a hand-signed letter (and a latent expectation that the celebrity had read the fan’s initial letter); such an exchange conferred to the fan a momentary sense of participation in the celebrity's extraordinary aura. Under Twitter, however, such an exchange does not occur, as that feeling of one-to-one interaction is absent; simply by looking elsewhere on the screen, one can confirm that a celebrity's tweet was received by two million other individuals. The closest a fan can come to that older modality of recognition is by sending a message to the celebrity that the celebrity then “re-tweets” to his broader following. Beyond the obvious levels of technological estrangement involved in such recognition is the fact that the identity of the re-tweeted fan will not be known by the celebrity’s other two million followers. That sense of sharing in the celebrity’s extraordinary aura is altered by an awareness that the very act of recognition largely entails performing one’s relative anonymity in front of the other wholly anonymous followers. As the associative, conspiratorial mindset of the star endlessly searches for fodder through which to maintain its image, fans allow what was previously a personal moment of recognition to be transformed into a public one. That is, the conditions through which one realises one’s personal subjectivity are, in fact, themselves becoming remade according to the logic of celebrity, in which priority is given to the simple fact of visibility over that of the actual object made visible. Against such an opaque cultural transformation, the recent rise of reactionary libertarianism and anti-collectivist sentiment is hardly surprising. ReferencesBaudrillard, Jean. Simulacra and Simulation. Ann Arbor: Michigan UP, 1994.Benjamin, Walter. Illuminations. New York: Harcourt, Brace and World, 1968. Dean, Jodi. Publicity’s Secret: How Technoculture Capitalizes on Democracy. Ithaca: Cornell UP, 2003. DeCordova, Richard. Picture Personalities: The Emergence of the Star System in America. Urbana: University of Illinois Press, 1990. Jenkins, Henry. “The Message of Twitter: ‘Here It Is’ and ‘Here I Am.’” Confessions of an Aca-Fan. 23 Aug. 2009. 15 Sep. 2009 < http://henryjenkins.org/2009/08/the_message_of_twitter.html >.Lyotard, Jean-Francois. The Postmodern Condition: A Report on Knowledge. Minneapolis: Minnesota UP, 1984.Ranciere, Jacques. The Future of the Image. New York: Verso, 2007.