Thread, making

It s easy to stretch a layer of dried white glue until it splits in half, and it s easy to yank a single strand of sewing thread into two pieces. Combine the glue with many strands of thread, however, and the resulting composite is most resistant to breakage—but only in the directions parallel to the threads. Make this composite and test its strength. 

Fill a cannula (Note 1) with heparin (1000 U/mL) and cannulate the hepatic portal vein about 1 inch below the point of branching into liver. Ease the cannula up to the point of branching and secure in place using the two threads, making sure that the knots are well away from the tapered tip of the cannula. If the cannulation is successful, blood will back-fill the cannula. 

Fig. 6.3. A DNA thread making two left-handed coils around each of a series of protein spools. A single spool consists of an octamer of histone proteins, two each of H2A, H2B, H3, and H4. The ninth histone protein, H1, may be located in the linker region between spools immediately adjacent to the spool. The DNA and histones make up the nucleosome. (From Calladine CR, Drew HR. Understanding DNA The Molecule and How It Works, 2nd Ed. New York Academic Press, 1997 with permission.)...

The individual threads making up the concentric lamellae or ultra-small layers in the cell wall have a diameter of about 77 A. in wood and about 88 A. in cotton 48). The tiny threads constituting the bulk of the cell wall consist predominantly of cellulose molecules which are themselves threadlike. The molecules are chains of D-glucose units linked uniformly by 1- 4 jS-D-glycosidic bonds. 

Each tobacco mosaic virus particle consists of one long thread of nucleic acid embedded in protein. The protein surrounds the nucleic acid in loops or in the fashion of screw threads making up the super-molecule. Treatment with phenol separates nucleic acids from protein. The nucleic acid obtained in this mild way remains infectious, and in a host cell can cause virus multiplication and consequent symptoms of disease. About 95% of the material is protein it consists of individual subunits with a molecular weight of 17,500, which exhibit a marked tendency to aggregate At neutral or slightly acidic pH the protein molecules aggregiite to little rozls, very similar to the intact virus particles both in shape and size. The amino acid sequence is now known. Mutants obtained by nitrous acid treatment (see above) show up differences in the amino acid sequence usually only one amino acid has been replaced, for example, serine by leucine, or leucine by phenylalanine. 

The Hartford-Empire 28 is a press-and-blow machine used to make articles such as drinking glasses (tumblers). It uses paste molds and the ware is rotated to avoid the mold seams jars with screw threads cannot be produced. The product leaves the machine as an almost closed, hoUow object and is finished by severing and fire-polishing with a bum-off machine. 

Silk (qv) suture is made from the threads spun by the silkworm Bombjx mori. The fiber is composed principally of the protein fibroin and has a natural coating composed of sericin gum. The gum is usually removed before braiding the silk yams to make sutures in a range of sizes. Fine silk sutures may be made by simply twisting the gum-coated silk yams to produce the desired diameter. White silk is undyed. Silk is either dyed black with logwood extract or blue with D C Blue No. 9. The suture may be uncoated or coated either with high molecular weight polydimethylsiloxane or with wax. 

The tubular positive plate uses rigid, porous fiber glass tubes covered with a perforated plastic foil as the active material retainer (Fig. 2). Dry lead oxide, PbO, and red lead, Pb O, are typically shaken into the tubes which are threaded over the grid spines. The open end is then sealed by a polyethylene bar. Patents describe a procedure for making a type of tube for the tubular positive plate (90) and a method for filling tubular plates of lead—acid batteries (91). Tubular positive plates are pickled by soaking in a sulfate solution and are then cured. Some proceed directiy to formation and do not requite the curing procedure. 

These are required to make threads, i.e. the final drawing, twisting and winding of cotton. Such motors must possess very smooth acceleration to eliminate breakage of threads. They are recommended to have a starting torque of 150-200% of T, and a pull-out torque of 200-275% of with a mean acceleration torque ol 150-175%. A normal acceleration time of 5-10 seconds is recommended. Faster acceleration may cause more breakages, while a slower acceleration may result in snarls and knots in the yarn as a result of insufficient tension. 

Nickel and its alloys form another important class of non-ferrous metals (Table 1.3). The superb creep resistance of the nickel-based superalloys is a key factor in designing the modern gas-turbine aero-engine. But nickel alloys even appear in a model steam engine. The flat plates in the firebox must be stayed together to resist the internal steam pressure (see Fig. 1.3). Some model-builders make these stays from pieces of monel rod because it is much stronger than copper, takes threads much better and is very corrosion resistant. 

Fig. 4.3. The flat plates that make up the firebox of a model steam boiler ore tied together with screwed stays. To make the threads pressure-tight they must be sealed with solder.

Double-thickness bags, not glued, with thread and marking (so as to make identification of the drug batch possible)... 

Tape may be made by a similar process. In this case the lubricant selected is a non-volatile oil. The preform is placed in the extruder and a rod extruded. The rod is then passed between a pair of calender rolls at about 60-80°C. The unsintered tape is often used for lapping wire and for making lapped tube. Sintering is carried out after fabrication. The current most important application of unsintered tape is in pipe-thread sealing. 

Specify type direct (specify type and make of coupling, keyed or screwed, and whether or not manufacturer is to supply), and single or double-ended spiral threads, supplying details V-belt or flat-belt sheave. 

OBasis of calculationa for recommended tool lolnt make-uo torque aaaumed the use of a thread compound containing 40-60% by weight of finely powdered metallic zinc applied thoroughly to all threads and shoulders, and a tensoe stress of 82.500 psi for column 7 and 75.000psi for columns 10.13, and 16... 

If so specified on the purchase order for round-thread casing only, jointers (two pieces coupled to make a standard length) may be furnished to a maximum of 5% of the order, but no length used in making a jointer shall be less than 5 ft. 

---