Plastic placement

Refractories may be preformed, ie, shaped, or formed and installed on-site, ie, specialties. Iimovations in placement and vessel constmction has led to a greater emphasis on specialty refractory products. Castables, gunning mixes, and plastic and ramming mixes are used either for repair or for complete new constmction of what is known as monolithic linings. The tendency to use monolithics instead of constmctions using shaped products has been steadily increasing. As of the mid-1990s, monolithic installations are as common as conventional shaped product constmction. 

The practice of molding inserts in place is usually employed to provide good holding power for plastic products, but there are drawbacks to this method. It normally takes a pin to support the insert, and since this pin is small in relation to the cored hole for the insert, it is easily bent or sheared under the influence of injection pressure. Should the insert fall out of position, there is danger of mold damage. Also, the hand placement of inserts contributes to cycle variation and with it potentially product quality degradation. Some of these problems can be overcome by higher mold expenditures,... 

Phototubes, multiplier, 56-59, 222 Placement error, 285-287 Planck s constant, 7, 8 Plastics, characterization by absorptiometry, 78, 79 Plateau, characteristic, 60 Platinum, determination by x-ray emission spectrography, 161, 328 L peaks, measured by Bragg, 25, 26, 35 L spectra, 35... 

Stenting Placement of a stent (a short metal or plastic tube) to allow blood flow through an artery. 

The main value of the counterforce technique is that it requires only half the explosive needed to accomplish the same result using standard formulas and placement. For example, a 14 inch diameter timber which requires 3% pounds of plastic explosive to cut conventionally can be sheared in two with counterforce charges of % pound each. Reinforced concrete piers 2 feet by 2 feet which can be broken conventionally by 17 pounds of explosive can be broken by counterforce charges of 4 pounds each. 

Add another layer of plastic explosive equal to the bottom layer and be sure the girth hitch knot is imbedded in this layer. The sandwiched layers of explosive and thermate should occupy no more than the bottom two-thirds of the container, the rest being open air space to provide buoyancy when the container is sealed. It is advisable to test the buoyancy of the charge (in fuel oil or gasoline, not water) prior to placement in the target. If additional buoyancy is needed, a block of wood can be added in the top of the container. 

Placement of plastic film on windows. It should be noted that application of film does not improve the strength of the glass, but only reduces glass... 

The investigation into the sabotage of Pan Am Flight 103, which left 269 dead, indicated that the explosive used was Semtex H, a plasticized mixture of hexahydro-l,3,5-trinitro-s-triazine and pentaerythritol tetranitrate, and that the amount used was half the quantity that the fledgling technique of Thermal Neutron Analysis (TNA) was designed to detect. Although the placement of the explosive device was fortuitous (from the terrorists point of view) and the suitcase had not been screened by TNA, this event killed the TNA prototype program. 

Structures with a high degree of reinforcement are susceptible to loss of bond between steel and concrete. This is particularly true in situations where the vibration required to consolidate the concrete is transmitted along the reinforcement and could cause loss of bond in previously placed partially hardened concrete. The adjustment of admixture dosage as placement proceeds ensures that the concrete remains plastic throughout the entire pouring period. 

Trinka, D.L. and M.L. Pritts (1992). Micropropagated raspberry plant establishment responds to weed control practices, plastics, row cover use, and fertilizer placement. J. Am. Soc. Hortic. Sci., 117 874-880. 

If plates are chosen as storage containers, it is necessary to isolate each sample from cross contamination and interaction with ambient air. This can be done by attaching lids or sealing the plates. A lid can be as simple as a plastic cover or a proprietary device that allows automated placement and removal. Sealing techniques range from cap mats, to adhesive seals, to heat seals. Traditionally, a sealed plate requires a manual step for seal removal. Recently a new technology provides automated seal removal. 

POE and polyolefin plastomers (POP) are ethylene alpha olefin copolymers produced using constrained geometry and metallocene catalyst. They differ from traditional polyolefins in that they have narrow molecular weight distribution and a regular placement of the octene co-monomer on the ethylene backbone. This highly uniform distribution allows for some unique plastic characteristics. 

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