Faying surface

The surface-emissive powers of fireballs depend strongly on fuel quantity and pressure just prior to release. Fay and Lewis (1977) found small surface-emissive powers for 0.1 kg (0.22 pound) of fuel (20 to 60 kW/m 6300 to 19,000 Btu/hr/ ft ). Hardee et al. (1978) measured 120 kW/m (38,000 Btu/hr/ft ). Moorhouse and Pritchard (1982) suggest an average surface-emissive power of 150 kW/m (47,500 Btu/hr/ft ), and a maximum value of 300 kW/m (95,000 Btu/hr/ft ), for industrialsized fireballs of pure vapor. Experiments by British Gas with BLEVEs involving fuel masses of 1000 to 2000 kg of butane or propane revealed surface-emissive powers between 320 and 350 kW/m (100,000-110,000 Btu/hr/ft Johnson et al. 1990). Emissive power, incident flux, and flame height data are summarized by Mudan (1984). 

The faying surface of the steel should be given a metal coating of either zinc (by spraying or galvanising) or aluminium spray. 

Such methods are also used for removing objectionable surface conditions, roughening faying surfaces, and preparation. 

If a power-driven wire wheel is used, care should be exercised to prevent burnishing. Burnishing can result in surface oxide embedment, which interferes with the proper wetting of the base metal by the filler metal. A base metal surface that is too smooth may not effectively allow filler metal wetting of the faying surfaces. 

The usual preventive measures79 in the galvanic corrosion are (i) use of indoor and shelters for outdoor exposure (ii) seal faying surfaces (iii) proper design for joining... 

Lubrication of the faying surfaces with low-viscosity, high-tenacity oils and greases to exclude direct contact with air. This is an adequate but not complete remedy. Phosphate conversion coatings of steels, for example, are used in conjunction with lubricants since they are porous and provide oil reservoirs.16... 

Dislocations can be introduced into some materials fay cutting and abrading (1,2) and by other mechanical processes (24,25). The importance of care in handling surfaces has been pointed out (24) since scratches and other damage can result. 

J. Fay, Theta functions on Riemann Surfaces (Springer Lecture Notes 352). 

The American Society for Testing and Materials (ASTM) standard E422 provides details for the construction of a single circuit, water-cooled calorimeter probe to measure heat flux [27]. Anderson and Stresino [28], Reed [29], and Fay [30] studied flames impinging on a so-called surface probe. In those studies, two identical, water-cooled copper plates were connected in series and separated by a thermal barrier. A single water-cooling circuit passed across both sections. The flame was traversed from the first to the second section. The water temperature rise through each plate was measured as a function of distance from the flame centerline. The data was inverted to determine the spatial heat flux distribution. See Reed... 

Jones and Yang used the principle of a silicone-rubber membrane separator as proposed for GC-MS for the development of a three-stage molecular separator to couple a mass spectrometer with a liquid chromatograph (Fig. B). The effluent from the chromatograph is led via a 0.025 on I.D. stainless-steel tube to the inlet of a flash evaporator, which consists of a 15-cni section of a 0.025-cm I.D. stainless-steel tubing, heated by an aluminium block. The vaporized stream expands into a 4-cm long section of 0.16-cm I.D. tubing and passes over the first membrane surface. The vapour not transmitted fay the meinbrane (a circular disc... 

The semiconfinuous layer of oxide was initially a continuous layer of oxide on the faying surfaces of the plates to be joined. Joint line remnants form because of insufficient cleaning of workpieces prior to welding or insufficient deformation at the faying surface interface due... 

Com-Stir tools (TWI) combine rotary motion (tool shoulder) with orbital motion (tool pin) to maximize the volume of material swept by pin-to-pin volume ratio (Ref 108) (Fig. 2.24). Moving the pin in an orbital motion produces a wider weld and increases oxide fragmentation on the interfacial (also known as faying) surfaces. In addition, the motion of the Com-Stir tool produces lower torque than the typical rotary motion FSW tool, reducing the amount of fixturing necessary to secure the workpiece. 

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