Polyurethane plugs

Products from the reactions are collected on Tenax cartridges, and the analytes desorbed by heating, or on polyurethane form plugs from which the analytes can be recovered by elution with a suitable organic solvent. 

Polyurethane foam (PUF) plugs were used to trap atrazine, simazine, DEA, and DIA when air was drawn through experimental chambers at 2.9m min . ° The plugs... 

Application verification (AV) monitors are devices that are placed within test plots to measure actual spray deposition that occurred during application. The main function of AV monitors is to show whether or not the intended amount of test material was actually deposited on the soil surface. Application monitors consisting of soil-filled containers, paper disks, polyurethane foam plugs, and glass Petri dishes have all been used successfully for this purpose. Prior to using a monitor in the field, it is important to determine that the test substance can indeed be successfully extracted from the monitor and that the compound will be stable on the monitor under field conditions... 

Aira Adsorption/solvent extraction with polyurethane foam plug HRGC/MS No data No data Ligocki and Pankow 1985... 

The reactor is an aerobic, plug flow, packed-bed biofihn reactor. Reticulated polyurethane (PUR), a foam with large surface area, is used as the substrate for microorganisms. The substantial area available on the PUR for contact results in a high biomass concentration and thus high reaction rates at short retention times. Biopur can be used in conjunction with soil vapor extraction technology. 

Concentrations of the gaseous nitroarenes, 1- and 2-nitronaphthalene, and 3-nitrobiphenyl in these 18 samples were determined concurrently with the PAHs, in this case sampling with a Teflon-impregnated glass fiber filter (TIGF)/polyurethane foam (PUF) apparatus (Fig. 10.4). The PUF plugs quantitatively trapped the gas-phase nitroaromatics, but not naphthalene and biphenyl and several 3-ring PAHs. 

For example, Fig. 10.37 shows a mutagram of an extract of ambient gas-phase POM collected on polyurethane foam plugs in Claremont, California, along with mutagrams of the extracts of PUF samples collected from environmental chamber studies of the OH radical initiated reactions of fluorene and naphthalene, respectively (Arey et al., 1992 Harger et al., 1992 Atkinson and Arey, 1994). Clearly, the mutagrams from the OH-initiated reactions are very similar to that of ambient air. 

While the batch process is the dominant one in current use, researchers and companies have attempted to create continuous bioreactor systems. Lopez et al. immobilized Candida rugosa in polymethacrylamide hydrazide beads and polyurethane foam 3 with the intent to achieve the continuous production of lipase enzymes. Despite flow problems with the polyurethane foam, it showed high lipolytic activity. Biomass buildup was problematic. Feijoo et al. immobilized Phanerochaete chry-sosporium on polyurethane foam in packed bed bioreactors under near-plug flow conditions. Continuous lignin peroxidase production was accomplished, the rate of which was studied as a function of recycle ratio. 

Air (CDDs) Collection of sample onto quartz fiber/polyurethane foam plug Soxhlet extraction with acetone clean-up with hexane and sulfuric acid followed by silica gel and alumina columns HRGC/MS (SIM) 0.5 pg/m3 70-90 Kuwata et al. 1993... 

In further work Saxena et al. [513] and Basu and Saxena [36] showed that the polyurethane-foam plug method had an extraction efficiency for PAHs of at least 88% from treated waters and 72% from raw water. 

Air Collected on XAD-2 resin sandwiched between polyurethane foam plugs, Soxhlet extracted with 6% ether/hexane GC/MS 1.0691 g / extract 114 Rudel et al. 2001... 

Air samples were taken at Ross Island, Cape Evans, and processed by filtering through polyurethane foam plugs connected in series (76). After extraction with an acetone-hexane mixture, determinations of 24 PCB congeners, p,p -DDT, p,p -DDE and lindane were accomplished by capillary GC with EC detection. Geochemical means (in pg m ) were 15.2, 2.0, 1.0 and 25.8 for the above compounds in the given order. Lindane concentrations were found to correlate well with seasonal variations (higher levels in summer and autumn), whereas the other chlorinated hydrocarbons showed no dependence on seasons. 

With a moisture sensitive product, moisture pick by this means can be quite rapid. Alternative materials to wool are either plastic shapes or plugs of expanded polystyrene, polyethylene or polyurethane foams. Closures can also be obtained which incorporate spring extensions. Such closures may have chambers which hold desiccants. Transit tests (vibration/drops) would be advised to check whether space fillers are necessary. 

HexceL [Hexcel] Thermoset polyurethane compds. encs ulants for cable plugging. 

The sample was collected using a high-volume air sampler, in which 13,000 m of air was sampled over a 7-day period. Air was aspirated through a glass fiber filter and two polyurethane foam plugs. Samples were subjected to Soxhlet extraction... 

While air and atmospheric analyses have been the subjects of many research articles, chromatographic determinations of pesticides in these types of sample are scant. Various methods for sampling pesticides in air have been reported, which use silica gel, Tenax, Chromosorb, XAD-2, polyurethane foam plug, glass fiber filters, and activated carbon or carbon fiber filters as sampling... 

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