Roll

Roll may refer to:

Places

Music

Vehicles and maneuvers

Other uses

Flight dynamics

Flight dynamics is the study of the performance, stability, and control of vehicles flying through the air or in outer space. It is concerned with how forces acting on the vehicle influence its speed and attitude with respect to time.

In fixed-wing aircraft, the changing orientation of the vehicle with respect to the local air flow is represented by two critical parameters, angle of attack ("alpha") and angle of sideslip ("beta"). These angles describe the vector direction of airspeed, important because it is the principal source of modulations in the aerodynamic forces and moments applied to the aircraft.

Spacecraft flight dynamics involve three forces: propulsive (rocket engine), gravitational, and lift and drag (when traveling through the earths or any other celestial atmosphere). Because aerodynamic forces involved with spacecraft flight are very small, this leaves gravity as the dominant force.

Aircraft and spacecraft share a critical interest in their orientation with respect to the earth horizon and heading, and this is represented by another set of angles, "yaw," "pitch" and "roll" which angles match their colloquial meaning, but also have formal definition as an Euler sequence. These angles are the product of the rotational equations of motion, where orientation responds to torque, just as the velocity of a vehicle responds to forces. For all flight vehicles, these two sets of dynamics, rotational and translational, operate simultaneously and in a coupled fashion to evolve the vehicle's state (orientation and velocity) trajectory.

Mail on Sunday (album)

Mail on Sunday is the debut studio album by American hip hop artist Flo Rida, and was released on March 18, 2008 via Atlantic, and Poe Boy Entertainment. It spawned three singles; the first, "Low" was number-one on the U.S. Billboard Hot 100 for ten weeks. The second, and third singles, "Elevator", and "In the Ayer", were successful as well, being top twenty hits. "Roll" featuring Sean Kingston was not an official single, but it managed to peak at number fifty-nine on the US Billboard Hot 100, and number forty-three on the Canadian Hot 100 due to digital sales in both countries.

Music

T-Pain, who laced the first single, is only one of the many featured guests throughout the album. Timbaland, who produced the second single "Elevator", is also featured on the track. Rick Ross, and Trey Songz made appearances as well.Lil Wayne has also been added to the list with assistance by young Memphian, Jamil Smith- while Sean Kingston appears on the J. R. Rotem-produced "Roll" the concept was created, and co-written by Compton rapper Spitfiya, from The Bullets Production Team, Various other guests include Birdman, Brisco. The third single is "In the Ayer" featuring will.i.am. The fourth single was scheduled to be "Money Right" featuring Brisco, and Rick Ross, but was canceled due to the release of his upcoming second studio album R.O.O.T.S. His second collaboration with T-Pain, "I Bet", as well as his collaboration with Trina, named "Bout It", both didn't make the final tracklist, but were recorded. As for production, J. R. Rotem, DJ Montay, and Timbaland all provided tracks for Mail on Sunday, among others.

Film (Iranian magazine)

Film (Persian:فیلم) is an Iranian film review magazine published for more than 30 years. The head-editor is Massoud Mehrabi.

References

External links

Lubrication theory

In fluid dynamics, lubrication theory describes the flow of fluids (liquids or gases) in a geometry in which one dimension is significantly smaller than the others. An example is the flow above air hockey tables, where the thickness of the air layer beneath the puck is much smaller than the dimensions of the puck itself.

Internal flows are those where the fluid is fully bounded. Internal flow lubrication theory has many industrial applications because of its role in the design of fluid bearings. Here a key goal of lubrication theory is to determine the pressure distribution in the fluid volume, and hence the forces on the bearing components. The working fluid in this case is often termed a lubricant.

Free film lubrication theory is concerned with the case in which one of the surfaces containing the fluid is a free surface. In that case the position of the free surface is itself unknown, and one goal of lubrication theory is then to determine this. Surface tension may then be significant, or even dominant. Issues of wetting and dewetting then arise. For very thin films (thickness less than one micrometre), additional intermolecular forces, such as Van der Waals forces or disjoining forces, may become significant.

List of film periodicals

Film periodicals combine discussion of individual films, genres and directors with in-depth considerations of the medium and the conditions of its production and reception. Their articles contrast with film reviewing in newspapers and magazines which principally serve as a consumer guide to movies.

Magazines and trade publications

Scholarly journals

References

Bibliography