Seal techniques

Textile uses are a relatively stable area and consist of the lamination of polyester foams to textile products, usually by flame lamination or electronic heat sealing techniques. Flexible or semirigid foams are used in engineered packaging in the form of special slab material. Flexible foams are also used to make filters (reticulated foam), sponges, scmbbers, fabric softener carriers, squeegees, paint appHcators, and directly appHed foam carpet backing. 

A discussion of this polymerization method would not be complete without mention of the development of specialized glassware utilized over the years. It has evolved from very elaborate, sophisticated, and specially designed glassware to fairly simple setups. Initially, elaborate break-seal technology was used to complete the entire polymerization process,143 similar to anionic polymerization methodology.17 Break-seal techniques were employed to fully understand many monomer structure-reactivity relationships these techniques are no longer needed. 

Two main principles of temperature measurement use thermocouples and the so-called resistance thermometer. In chemical plants both methods were applied because they are easy to fit and to maintain.The accuracy of the measurement is influenced by, for example, radiation, which must be taken into account. Thermocouples can be inserted into the pressure system using special sealing techniques, or they may be mounted within a protective tube which is introduced into the pressurized volume. Thermocouple-wires are usually protected with an isulating input in closed-end capillaries with outer diameters of at least 0.5 mm. Thermocouples are technically well tested for pressures up to 6 kbar and temperatures to approx. 800°C. Above these ranges the exact measurement is negatively influenced by several parameters, and the deviations must be taken into account. The accuracy of the temperature measurement devices is normally better than 1 °C. 

Fire and Explosion Prevemloa—study areas have included fa) ignition, thl flame propagation. fire detection and alarm, (d) suppression and extinguishing, and (e) methanometry. Devices and techniques tested have included explosion-proof bulkheads, coal dust and rock dust analyzers, ignition suppression devices for face equipment, and remote sealing techniques. 

A. Roth, Vacuum Sealing Techniques, Pergamon Press, Oxford, 1966. 

Because of the low output per unit of area of solar stills, even small distillate and brine leaks cannot be tolerated. Some of the sealing techniques used successfully in laboratory investigations have been found inadequate in field installations. 

It has been suggested that complete purification of the TNT is not really necessary in some cases, especially with modern bomb assembly and sealing techniques and the availability of additives to prevent exudation of cast TNT mixts (Ref 6). This proposal merits serious consideration in the light of the problems and energy loss involved in purification as discussed above. The use of low temp during the initial stages of nitration promises to substantially reduce formation of the meta isomers, which will correspondingly facilitate the purification step. This development is discussed under Preparation . Other refs to TNT purification are cited under "Refs (Refs 5,7,10 12)... 

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. 

The process is used for high volume BM of very small containers such as pharmaceutical vials and whiskey bottles. A multi-cavity mold is used with an extruded parison whose circumference approaches twice the total width of the closely spaced cavities. Before the mold closes, the parison is stretched and semi-flattened laterally so that it extends across the full width of the cavities. The process is usually combined with blow/fill/seal techniques. 

A number of problems connected with battery construction and operation, such as rechargeability into the two-phase region which requires improvement of sulfur transport away from the solid electrolyte and carbon surface,and development of sealing techniques and of ceramic mass production, have been to a great extent overcome. The remaining difficulties are primarily connected with the reliability and cycle life of the battery. 

A number of recent references have focused on the problems associated with the design and manufacture of heat pipes. Most notable are early works by Feldman [16] and Brennan and Kroliczek [17], and more recent ones by Peterson [7] and Faghri [8]. In addition to such factors as cost, size, weight, reliability, fluid inventory, and construction and sealing techniques,... 

A glass ampoule sample holder, as described in Chiu (125), is shown in Figure 6,17. Such a sealed sample container has been found to withstand an internal pressure of up to 1800 psi and is suitable to be used as a microreactor to study most chemical reactions. An ampoule holder, constructed from silver or aluminum metal, is used to support the ampoule in the DSC sample chamber. Liquid or solid samples are introduced into the ampoules by a syringe. The ampoule sealing technique has been described elsewhere (126). 

The two main disadvantages of cartridge trays are leakage around the circumference and their relatively high cost. A vertical metal seal ring is often installed around each tray to minimize leakage. Success-Ail operation at liquid rates lower than 1 gpm has been claimed with a sophisticated variation of this sealing technique (308). 

The use of wax to seal the test piece into the dish requires care and dexterity in order to avoid minute leaks. Such leaks are difficult to detect, and it is useful to test the. sealing technique using a metal template instead of the polymeric sample. It is also sensible to make measurements on a number of samples of the same material at the same time. If one of the seals is leaking, the transmission rate will be significantly higher than the others and the results can be discarded. 

Perkins KL, Licari JJ. Development of low-cost, high-reliability sealing techniques for hybrid microcircuit packages. NAS-831992, http //ntrs.nasa.gov/details.jsp R=311623 Aug. 1977. 

Perkins, K. L., and Licari, J. J., Development of Low-Cost, High-Reliability Sealing Techniques for Hybrid Microcircuit Packages, Final Report, NASA, NAS-831992 (Aug. 1977)... 

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