Frictional device

The frictional loss term F in Equation 4-28 represents the loss of mechanical energy resulting from friction and includes losses resulting from flow through lengths of pipe fittings such as valves, elbows, orifices and pipe entrances and exits. For each frictional device a loss term of the following form is used ... 

Pendulum Friction Device Test. See under Friction Sensitivity Tests... 

Friction Sensitivity. When using a Type A "Pendulum Friction Device with a steel shoe and the procedure described in USBur... 

Friction Sensitivity. When using a Type A "Pendulum Friction Device with a steel shoe and the procedure described in USBur Mines Bull 346(1931) and in lEC 25,664-5 (1925) pentryl proved to be somewhat more sen sitive to friction than tetryl and very much more sensitive than PA or TNT(Ref 4, p 1386)... 

A work, astonninj column, or a working party. In this sense a petard may be considered as a toi iwdo. Torpedoes for land defense are usually shells of small caliber, 6 and 12 pounders, provided with a percussion or friction device which causes an explosion when the ground over the torpedo is stepped on. Sometimes sevei l are laid in a row, and a piece of board placed over them to increase the chances of explosion. 

With the X-ray technique described stresses in polymer wear films can be measured. One could incorporate a pin-on-disk friction device within the opening of the X-ray camera and conduct in situ measurements. The stresses developed in the film with repeated passes, increasing load, varied sliding speeds and polymer compositions can be measured. This could lead to a better understanding of the role of stresses in polymers on their wear behavior. 

These salts are mixed (compounded) with a fuel, usually iron powder, to form a chlorate candle, which produces oxygen by continuous reaction. The fuel is used to generate heat by oxidation. Once the reaction begins, oxygen is released from the hot salt by thermal decomposition (a thermal shield is used around the generator). A portion of the oxygen reacts with the fuel to produce more heat which produces more oxygen, and so on. Initiation of the reaction can be achieved by a percussion device, friction device or electric wire. ICAO A2... 

The processor is equally concerned with the sensitivity of mixtures to impact and friction. Devices that permit a weight to drop from measured heights on a small sample (mostly 20 mg) have been designed among others by the Bureau of Mines and by Picatinny Arsenal. 

False-twisting is most widely used for texturing fine tex yarns. In the first step, they are heated to about 220°C and 185°C in the cases of nylon-6,6 and nylon-6, respectively. This is followed by twisting to introduce 30-40 turns/cm using spindle or friction devices. The yarn is then cooled and untwisted. The resulting product is characterized by good elasticity. If bulk is required, the yarn is either subjected to a second heat-twist-untwist step or treated with steam or hot water in an autoclave. 

The most popular friction devices according to the TYROSAFE report are the SCRIM (used by nine EU countries) and the GripTester, towed device (used by eight EU countries). Two EU countries use the Skiddometer BVll and two EU countries use the SRM (Stuttgarter Reibungsmesser) or RoadSTAR (Road Surface Tester of Arsenal Research). All other devices are used by only one EU country (TYROSAFE 2008). An overview of highway and runway friction devices is also provided by NCFIRP web-only document 108 (Hall et al. 2009). 

PRACTICAL TESTS OF THE PROCESS OF CONVEYANCE EMERGENCY ARRESTING WITH USE OF A FRICTION DEVICE... 

To describe the process of emergency arrest of conveyances in the friction device after they over-travel the upper limit, appropriate systems were developed to measure and record the following values ... 

Table 1. Selected results of emergency arrest tests with the HS2W friction device...

The aim of this series of tests was to investigate the actual parameters of a simiflated emergency over-travel event in the headframe when this conveyance is being arrested in the friction device with the so-called dogging system. The arresting device equipped with dog systems to catch the conveyances has been named the mobile crash beams—HWR (Figure 6). 

Summing up the results of the tests involving an emergency arrest of a hoist in a friction device, it should be noted that the brake forces obtained in the tests corresponded to those assumed in the simulation calculations. 

Hansel J., W6jcik M. 1996. Cierne urzqdzenia do awaryjnego hamowania naczyn wyciqgowych (Friction devices for emergency conveyance arresting), Shaft Transport 96 International Scientific and Technical Conference Materials, Vol. 2, Gliwice... 

Magnetorque electric load brake Electric brake Rotor Aluminum fan Field assembly Spring mechanism Magnefic brakes Friction devices Brake shoes... 

Brake An electromechanical friction device employed to stop and hold a load. When the brake is set, a spring pulls the braking surface into contact with a braking wheel which is directly coupled to the motor shaft. 

Friction devices Clutches, brakes / + - - Stability, heat dissipation... 

Friction devices such as vehicle brakes and electric motors Tobacco smoke. 

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