Striking Surface

About 80-90% of the elemental P produced is reoxidized to (pure) phosphoric acid (p. 521). The rest is used to make phosphorus oxides (p. 503). sulfides (p. 506), phosphorus chlorides and oxochloride (p. 4%). and organic P compounds. A small amount is convened to red phos rftorus (see below) for use in the striking surface of matches for pyrotechnics and as a flame retarding agent (in polyamides). Bulk price for P4 is S2.00/kg. 

Streich-flache,/. striking surface (for matches), rubber, -holz, -holzchen, n. friction match, -instrument, n. stringed instrument, -kappe, /. (Expl.) friction cap. -kasten, m. (Dyeing) color tub. -kraut, n. dyer s rocket, -lack, m. brushing lacquer, -masse, /. friction composition (for matches), -mischung, /. coating mixture, -muster, m. (Paper) stained-paper pattern, -ofen, m. reverberatory furnace. -papier, n. coated paper, -stein, m. touchstone hone, -torf, m. pressed peat, molded peat. -zUndholzchen, n. friction match. 

A safety match head is, essentially, K chlorate in a matrix of animal glue. The striking strip is composed of red P in a similar binder. Use of additives and adjustments in the mfg process results in a safety match which ignites easily when rubbed on the striking surface. The friction and contact of K chlorate crystals with red P results in the ignition of the match head which, in turn, causes the ignition of paraffin impregnated in the match splint... 

Red phosphorus is found in the striking surface of matchboxes. The red heads contain antimony sulfide. 

The only element that was discovered in body fluids (urine). This is plausible, as P plays a main role in all life processes. It is one of the five elements that make up DNA (besides C, H, N, and 0 evolution did not require anything else to code all life). The P-O-P bond, phosphoric acid anhydride, is the universal energy currency in cells. The skeletons of mammals consists of Ca phosphate (hydroxylapatite). The element is encountered in several allotropic modifications white phosphorus (soft, pyrophoric P4, very toxic), red phosphorus (nontoxic, used to make the striking surface of matchboxes), black phosphorus (formed under high pressures). Phosphates are indispensable as fertilizer, but less desirable in washing agents as the waste water is too concentrated with this substance (eutrophication). It has a rich chemistry, is the basis for powerful insecticides, but also for warfare agents. A versatile element. 

Tiny "sheath" Poynting component strikes surface... 

Maximum reflected pressure (wave strikes surface head-on) 28 4100... 

Striking Surface of Swedish Matches consists of a compound prepared by... 

Two types of pivotal steel hammers were used to provide repetitive impacts. One provided a 0.25-cm wide strike surface with a cylindrical radius of 63.5 cm. This was 1.4 cm long and had an effective mass of 7.8 gms. This hammer was operated at 40 Hz, providing 31 X 103 ergs of impact energy at a velocity of 89 cm/sec. The second hammer had a... 

In the rimfire primer, an integral part of the small-calibre cartridge, the ignition mix, or primer composition is slurried into the cartridge base, crimped, then oven dried at relatively low temperatures (<110°F). The base of the cartridge serves as the striking surface, and the top of the crimp, supported by the weapon breech lip, serves as the anvil. 

Therp.rore, the radiation emitted from surface Ai will strike surface A at a rate ul 2,74 10-° W. 

Ffj = the fraction of the radiation leaving surface i that strikes. surface j directly... 

The view factor represents tlie fraction of radiation leaving surface 1 that strikes surface 2 directly, and F21 represents the fraction of radiation leaving surface 2 that strikes surface 1 directly. Note that the radiation that strikes a surface does not need to be absorbed by that surface. Also, radiation that strikes a surface after being reflected by other surfaces is not considered in the evaluation of view factors. 

Fii - 0. since no radiation leaving surface I strikes itself F,-2 = I. since all radiation leaving surface I strikes surface 2... 

Consider the geometry in Pig. 13-11, which is infinitely long in the direction perpendicular to the plane of the paper. The radiation that leaves surface 1 and strikes the combined surfaces 2 and 3 is equal to the sum of the radiation that strikes surfaces 2 and 3. Therefore, the view factor from surface 1 to the combined surfaces of 2 and 3 is... 

Radiaiioii leaving the entire surface I that strikes surface 2. ... 

Radiation leaving the entire surface 2 Ihal strikes surface fVV)... 

Consider two black surfaces of arbitrary shape maintained at uniform temperatures T and Ti, as shown in fig. 13 -18, Recognizing that radiation leaves a black surface at a rate of E/, - crT" per unit surface area and that the view factor i, 2 represents the fraction of radiation leaving surface 1 that strikes surface 2, the net rate of radiation heat transfer from surface 1 to surface 2 can be expressed as... 

Radiaton heal transfer between surfaces depends on the orientation of the surfaces relative to each other. In a radiation. analysis, this effect is accounted for by the geometric parameter vie.iv facior. The vretv factor ftoni a surface i to a. surface j is denoted by or F j, and is defined as the fraction of the radiation leaving surface i that strikes surface j directly. The view factors between differential and finite surfaces are expressed as... 

Shape the cover into a tube with striking surface on the inside and tape. Make sure the folded cover will fit tightly around the taped match heads. Leave cover open at opposite end for insertion of the matches. 

Punch many closely spaced small holes between the lines marked on the can to form a striking surface for the matches. Be careful not to seriously deform can. 

---