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The development of several types of a urea transducer suitable for rapid, continuous determination of urea is described. The transducer is called an enzyme electrode because it is made by placing a thin film of urease enzyme immobilized in acrylamide gel over the surface of a Beckman cationic electrode responsive to ammonium ions. The immobilized enzyme catalyzes the decomposition of urea to ammonium ion at the surface of the cat-

A key cotton fiber quality property is micronaire, which acts as an indicator of the fiber's maturity and fineness. Previous studies have demonstrated the ability of Near Infrared (NIR) instrumentation to measure these cotton properties with varying degrees of success, but these studies did not provide conclusions on the capabilities of NIR spectroscopy as a general technique for these analyses. Recent advances in NIR technology could result in improved measurements of these cotton properties. A comparative investigation was implemented to determine the capabilities of modern commercial bench-top and portable NIR systems to monitor cotton fiber micronaire, maturity, and fineness in order to gain insight as to the "universality" of the NIR measurements for these fiber properties. Cotton samples were analyzed on five commercial systems and an older, custom-built system. Very good spectral agreement was observed between the portable and bench-top NIR units. The rapid and simultaneous measurement of cotton micronaire, maturity, and fineness by multiple commercial systems was demonstrated and compared favorably to the custom system, but without the delay and cost in building custom units. For the benchtop NIR systems, all end-state criteria were successfully meet. The "universal" nature of the NIR measurement of these cotton fiber properties was validated for commercial NIR systems. As expected, the NIR results for the portable NIR units were normally not as good as those for the bench-top instruments, but they were very acceptable for demonstrating the potential for the portable units to measure these cotton fiber properties.

A comparative study was conducted to identify the effects of processing on physical and combustion properties of needlepunched (NP) and hydroentangled (H-E) nonwoven fabrics produced from fibers of white fiber cotton and a naturally colored brown fiber cotton. A significantly higher degree of flame retardancy (FR) in was observed in fabrics produced from brown cotton fibers compared with white fibers. Calorimetry revealed lower heat release capacity, lower peak heat release rate, and total heat release from brown fibers compared with white fibers. The ash content was also higher in brown fiber samples suggesting higher levels of inorganic elements in the brown fibers. Elemental analyses revealed brown cotton fibers had higher levels of known FR elements including phosphorous and magnesium. The H-E process reduced FR in brown fabrics, which also correlated with a reduction in phosphorous. However, brown H-E fabrics still maintained higher FR than white H-E fabrics. Water content analysis indicated higher water levels in brown fibers, particularly brown greige fibers, which correlated with increased FR. Processing parameters such as energy of H-E did not affect combustion of the two fabric types. Scouring of the brown fiber fabrics reduced, but did not remove coloration, while scouring and bleaching removed the brown color completely. Scouring alone, or scouring and bleaching, completely removed the higher FR properties of the brown fiber fabrics. The results indicate that the mechanism of FR in brown cotton fibers is dependent on multiple compositional factors that may include element content, water content, and compounds related to coloration.