Length grading

The ability of this technology to segregate catalyst at any desired length was demonstrated in a test performed on 1/32 inch diameter extruded catalyst. The spent catalyst was stripped of oil and then length graded into three fractions a short fraction of less than 1.5 mm in length, a mid-range fraction between 1.5 mm and... 

Without length grading, the refiner was planning to ship all of the material to reclamation. Application of LDG provided an economical way to recover a high quality product as well as reduce the amount of waste catalyst. 

Density grading is a technique by which catalyst particles are segregated based on their individual densities. This process is most often performed following length grading since the... 

Table 3. Length graded Fresh 1/16 Inch Cobalt/Moly Particle Average...

The chief parameters for processing of the fiber are fiber length, uniformity of length, grade (amount of impurities, called trash), micronaire (maturity and coarseness), strength, elongation (which is approximately 7%) and cohesiveness (cohesion between the fibers). Moisture uptake is 8% at 65% r.h. 

The manufacture of MDF, with a few exceptions, dupHcates the manufacture methods for dry-process hardboard, described at length hereia. One exception to it is that most MDF is made ia the medium-density range, 640—800 kg/m although small amounts are made at lower or higher densities. Second, the vast majority of MDF is made with UF resia adhesives with resia requhemeats ia the 7—11% range, and wax is usually added at the 0.50—0.75% level. A small amount of exterior-grade MDF is made with isocyanate resia. 

Henequen. Agavefourcroydes grows ia Mexico where it was first cultivated by the Mayans ia the Yucatan (Yucatan Sisal). The plant produces for 20—30 years. The lower bottom leaves, which are up to 2 m long and 10—15 cm wide, are cut, machine decorticated, and cleaned. Henequen fibers are white to yellowish red and are inferior to sisal ia strength, cleanliness, texture, and length, the other grading criteria. Henequen is grown for local use ia Cuba (Cuban Sisal) and El Salvador. Twiae, small ropes, coarse mgs, and sacks are made commercially from henequen. 

The location of exchangers is the key to maintenance. Usually the back head is kept at a distance of about three meters from the piperack support columns. Access equipment must be able to get in and remove the sheU cover and flange head. Access area must also be provided to handle and remove the sheU cover usually located under the piperack. The tube-pulling or rodding-out area must be kept clear to allow access to the channel end. This space should be at least equal to the tube length and about two meters from the tube sheet location. Tube removal space should be allowed for but is not mandatory if grade-mounted heat exchangers are used and mobile maintenance equipment employed to pick up the entire unit and transfer it to the repair shop. 

No. 2 Heavy Melting Steel. Supphed ia more than one grade form based on length and width requirements and a minimum thickness of about 0.3 cm (1/8 ia.), this scrap is lower quaUty than No. 1 heavy melting. There is the possible iaclusion of a wide variety of items such as alloy steels and coated materials. 

Working-grade thermometers, conventionally called industrial resistance thermometers, are generally smaller than the SPRT element and may be as small as 2.5 mm in diameter and 10 mm in length. These are available in various 0°C resistances, eg, 100, 200, and 500 Q. They are available as unsheathed elements or in a wide variety of sheaths and enclosures, both standard and custom. They are relatively inexpensive. They are usually made to be interchangeable, without relying on iadividual cahbration, within limits of 0.25 K or closer upon special order. A typical tolerance statement for a precision-class industrial resistance thermometer is... 

Many grades of interlayer are produced to meet specific length, width, adhesion, stiffness, surface roughness, color (93,94), and other requirements of the laminator and end use. Sheet can be suppHed with vinyl alcohol content from 15 to about 23 wt %, depending on the suppHer and appHcation. A common interlayer thickness for automobile windshields is 0.76 mm, but interlayer used for architectural or aircraft glaring appHcations, for example, may be much thinner or thicker. There are also special grades to bond rear-view mirrors to windshields (95,96) and to adhere the components of solar cells (97,98). Multilayer coextmded sheet, each component of which provides a separate property not possible in monolithic sheet, can also be made (99—101). 

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