Crocking

Macromolecular stmcture and supermolecular organization also affect dye affinity. Drawn (oriented) nylon-6 has more of a random open stmcture than nylon-6,6 (172). Nylon-6, therefore, dyes more rapidly than nylon-6,6, but is also more susceptible to color crocking, especially with disperse dyes. 

Fastness to Crocking. Crocking is defined as the transfer of color from the surface of a dyed fabric to another surface by mbbing. AATCC test method no. 8 is a method by which a colored test fabric swatch is fastened to the base of a Crockmeter and mbbed against a white crock test cloth under controlled conditions. Color transfer to the white cloth is evaluated by comparison with the AATCC Chromatic Transference Scale. A similar method, AATCC 116, uses a Rotary Vertical Crockmeter, which requires a smaller area of test fabric than the Crockmeter. 

Stress Corrosion Crocking. Stress corrosion cracking occurs from the combined action of corrosion and stress. The corrosion may be initiated by improper chemical cleaning, high dissolved oxygen levels, pH excursions in the boiler water, the presence of free hydroxide, and high levels of chlorides. Stresses are either residual in the metal or caused by thermal excursions. Rapid startup or shutdown can cause or further aggravate stresses. Tube failures occur near stressed areas such as welds, supports, or cold worked areas. 

Deep C t lytic Crocking. This process is a variation of fluid catalytic cracking. It uses heavy petroleum fractions, such as heavy vacuum gas oil, to produce propylene- and butylene-rich gaseous products and an aromatic-rich Hquid product. The Hquid product contains predorninantiy ben2ene, toluene, and xylene (see BTX processing). This process is being developed by SINOPEC in China (42,73). SINOPEC is currentiy converting one of its fluid catalytic units into a demonstration unit with a capacity of 60,000 t/yr of vacuum gas oil feedstock. 

Superffex C t lytic Crocking. A new process called Superflex is being commercialized to produce predorninantiy propylene and butylenes from low valued hydrocarbon streams from an olefins complex (74). In this process, raffinates (from the aromatics recovery unit and the B—B stream after the recovery of isobutylene) and pyrolysis gasoline (after the removal of the C —Cg aromatics fraction) are catalyticaHy cracked to produce propylene, isobutylene, and a cmde C —Cg aromatics fraction. AH other by-products are recycled to extinction. 

In a 5-I, crock or battery jar, provided with a powerful mechanical stirrer, are placed 3.5 1. of water and 249 g. (2.16 moles) of thiophosgenc (p. 86) (Note x). To the vigorously Stirred (Note 2) mixture is added slowly 255 g. (2 moles) of /)-chloroaniline during about one-half hour. The stirring is continued for about an additional half-hour. The dark brown oil is separated, washed with 50 cc. of 10 per cent hydrochloric acid, and placed in a flask for steam distillation. 

In a copper or iron kettle of 4-I. capacity is placed a solution of 200 g. of d-tartaric acid and 700 g. of sodium hydroxide in 1400 cc. of water. A 12-I. flask through which cold water is run is placed in the mouth of the kettle in order to prevent loss of water vapor, and the mixture is boiled gently over an open flame for four hours. The solution is now transferred to a 12-I. flask or crock and partially neutralized with 1400 cc. of commercial hydrochloric acid (density 1.19). To the still alkaline solution is now added just enough sodium sulfide to precipitate all the iron or copper which has been dissolved from the kettle (Note i). The filtered solution is then just acidified with hydrochloric acid, boiled to expel all hydrogen sulfide, and made very faintly alkaline to phenolphthalein with sodium hydroxide solution. To the hot solution is then added a concentrated solution of 300 g. of anhydrous calcium chloride which causes an immediate precipitation of calcium tff-tartrate and mesotartrate. 

Fig. 19.10. A cermet is a particulate composite of a ceramic (WC) in a metal (Co). A crock in the ceramic is arrested by plasticity in the cobalt.

Fig. 25.6. Fibres toughen by pulling out of the fracture surface, absorbing energy os the crock opens.

Abnisbohne,/. jequirity bean, abrussecht, a. fast to rubbing, not crocking, abrussen, v.i. (of colored goods) rub off, crock, abrtisten. v.i. disarm. —v.t. dismount, abrutschen, v.i. slip, slide (off or down). — v.t. wear off or out. 

Scherbe, /. potsherd, shard fragment, piece crock, pot (esp. fiowerpot) cupel scorifier (Ceram.) body. 

Topas, m. topaz, -fiuss, m. artificial topaz, topasgelb, a. topaz-yellow, topaz. Topasschorlit, m. pycnite (columnar topaz). Topf, m. pot jar, crock top. 

Caliper for wear and MAINTENANCE check for crocks (both ends)... 

Body crocks — goqe for weor (both sides)... 

Increosing stress intensity with crock extension... 

Double torsion single-edge crocked plote... 

Bischoff, J.L., Rosenbauer, R.J., Aruscavage, P.J., Baedecker, A.L. and Crock, J.G. (1983) Seafloor massive sulfide deposits from 2I°N, East Pacific Rise Juan de Fuca Ridge and Galapagos rift Bulk chemical composition and economic implications. Econ. Geo ., 78, I711-1720. 

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