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Rollback (computing)
Rollback is the operation of restoring a system to a prior consistent state by undoing changes, most commonly discarding the updates made by an uncommitted database transaction.
Rollcage
A rollcage, also known as a safety cage or safety cell, is a multi-tubular structure fitted in a competition car's cockpit to protect occupants during rollovers and serious accidents.
Roller brake
The roller brake is a Shimano cable-operated drum brake for bicycles, in which rollers press steel shoes against a drum inside the hub; it appeared in 1995 as the INTER-M.
Roller linear guide
A roller linear guide is a profiled rail linear bearing in which cylindrical rollers recirculate between a rail and a runner block, carrying heavier loads than ball guides.
Roller screw
A roller screw is a mechanical transmission that converts rotary motion into linear motion using rollers rolling between a screw shaft and a nut, carrying about three times the load of a ball screw.
Roller-compacted concrete
Roller-compacted concrete (RCC), also known as rollcrete, is a dry, zero-slump concrete placed in layers with earthmoving equipment and compacted by vibratory rollers, widely used for concrete gravity dams and heavy-duty pavements.
Roller-compacted concrete dam
A roller-compacted concrete dam is a concrete gravity dam built by placing dry concrete in horizontal layers compacted with vibratory rollers, cutting costs 25 to 40 percent.
Roller-delayed blowback
Roller-delayed blowback is a firearm operating principle in which rollers impose a mechanical disadvantage that delays the bolt, used in the CETME, the Heckler & Koch G3, and the MP5.
Roller-integrated compaction
Roller-integrated compaction, originating in Europe as continuous compaction control and now called intelligent compaction, lets vibratory rollers measure soil stiffness in real time using accelerometers and GPS.
Roller-Walker
Roller-Walker (ローラーウォーカー) is a leg-wheel hybrid quadruped developed by Shigeo Hirose at the Tokyo Institute of Technology in 1995, which walks on rugged terrain and skates on smooth ground.
Rolleston Coal Mine
The Rolleston Coal Mine, marketed as Rolleston Open Cut, is a large open-cut thermal coal mine in Queensland's Bowen Basin, mining since 2005 and owned by Glencore.
Rollin' Justin
Rollin' Justin is a wheeled humanoid research robot built by the German Aerospace Center (DLR), first presented in 2008 for mobile manipulation in household and space settings.
Rolling (metalworking)
Rolling, or metal rolling, is a metalworking process that reduces or shapes metal stock by passing it between rotating rolls, performed either hot or cold.
Rolling blackout
A rolling blackout, also called loadshedding, is a deliberate, rotating shutdown of power to blocks of customers to keep demand from exceeding supply and protect the grid.
Rolling coal
Rolling coal, also called rolling coal, is the practice of modifying a diesel truck to emit large plumes of black exhaust smoke at other road users.
Rolling contact kinematics
Rolling contact kinematics is the branch of mechanics describing how two bodies in contact roll without slipping, supplying the nonholonomic constraint equations used to plan in-hand manipulation and wheeled locomotion.
Rolling horizon optimization
Rolling horizon optimization is a decision method that repeatedly solves an optimization model over a moving time window, implementing only immediate decisions before re-solving as new information arrives.
Rolling lift
Rolling lift is a bascule bridge where the span rolls along a curved track rather than pivoting, as in the design patented by William Scherzer in 1893.
Rolling paper
Rolling paper, also called cigarette paper, is a thin, porous paper used to wrap cut tobacco for cigarettes and roll-your-own smoking, made from flax, hemp, or wood pulp.
Rolling pin
A rolling pin is a cylindrical kitchen tool for flattening dough into even sheets, in handled American and tapered French styles, made of wood, marble, or steel.
Rolling stock
Rolling stock, also called rail vehicles, is the collective term for all vehicles used on a railway track, from locomotives and multiple units to hauled coaches, freight wagons, and service stock.
Rolling stock manufacturing industry
The rolling stock manufacturing industry builds railway vehicles like locomotives, carriages, and wagons, concentrated so the ten largest firms held over 70% of a EUR 54.7 billion market in 2017.
Rolling stock of Japan
The rolling stock of Japan comprises the locomotives, passenger vehicles, and freight wagons on the national network, run by Japanese National Railways until its 1987 privatization into seven JR companies.
Rolling stock of Network SouthEast
The rolling stock of Network SouthEast was the fleet of electric and diesel trains operated by the British Rail sector created in 1986 to run London commuter services.
Rolling stock of Serbian Railways
The rolling stock of Serbian Railways, Железнице Србије, is the fleet of locomotives, multiple units, coaches, and wagons split between Srbija Voz and Srbija Kargo since 2015.
Rolling stock of South Africa
Rolling stock of South Africa covers the locomotives, coaches, multiple units, and wagons serving Transnet, PRASA, and the Gautrain, shaped by the 1,067 mm Cape gauge.
Rolling stock of the Bluebell Railway
The rolling stock of the Bluebell Railway is the collection of preserved carriages, wagons, and multiple units of the Bluebell Railway, a heritage railway in Sussex running trains since 1960.
Rolling stock of the Watercress Line
The rolling stock of the Watercress Line is the fleet of steam locomotives, diesels, and Mark 1 carriages preserved on the Mid-Hants Railway, a heritage line in Hampshire.
Rollon
Rollon is an Italian manufacturer of linear motion systems, including linear guides, telescopic rails, actuators, and ball screws, founded in 1975 and part of The Timken Company since 2018.
Rollover protection structure
A rollover protection structure (ROPS) is a cab frame or rollover bar attached to tractors and earth-moving machines, protecting operators during overturns when used with a seatbelt.