Opacity large

Source sampling of particulates requites isokinetic removal of a composite sample from the stack or vent effluent to determine representative emission rates. Samples are coUected either extractively or using an in-stack filter EPA Method 5 is representative of extractive sampling, EPA Method 17 of in-stack filtration. Other means of source sampling have been used, but they have been largely supplanted by EPA methods. Continuous in-stack monitors of opacity utilize attenuation of radiation across the effluent. Opacity measurements are affected by the particle size, shape, size distribution, refractive index, and the wavelength of the radiation (25,26). 

Many different combinations of surfactant and protective coUoid are used in emulsion polymerizations of vinyl acetate as stabilizers. The properties of the emulsion and the polymeric film depend to a large extent on the identity and quantity of the stabilizers. The choice of stabilizer affects the mean and distribution of particle size which affects the rheology and film formation. The stabilizer system also impacts the stabiUty of the emulsion to mechanical shear, temperature change, and compounding. Characteristics of the coalesced resin affected by the stabilizer include tack, smoothness, opacity, water resistance, and film strength (41,42). 

NB The data compares a syndiotactic material with a melt index of 30 and an isotaclic material with an index of 0.3. This should however not invalidate the large differences seen in such properties as modulus, impact strength and opacity.)... 

Amount if too little titanium dioxide is added, the distance between particles is too large and there is not enough opacity, while if the titanium content is too high, the particles interfere with each other and poor efficiency is obtained. 

One of the primary limitations of PET is related to its slow rate of crystallization from the melt. A consequence of this is that relatively long cycle times are required to provide crystallinity in PET. When this is achieved, it is often accompanied by opacity and brittleness, due to the relatively large size of crystallites formed by thermal crystallization. Crystallinity itself is often desirable in moulded parts, due to the higher thermal and mechanical stability associated with it. Crystallinity is especially desirable when parts are intended to be subjected to elevated temperatures since if the PET components are amorphous they will anneal at temperatures above 80 °C. 

Very recently Tokita and Tanaka have performed a macroscopic measurement of the friction coefficient and have found its dramatic decrease with slight opacity near the critical point [86]. We conjecture that such a large anomaly was caused by stationary domain structures with large spatial scales and not by the thermal fluctuations decaying diffusively. 

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