Gum-formers

The fuel oils coming out of olefin plants are also characterized by an abundance of polynuclear aromatic molecules, (Same definition as for Figure 2—1). They are sometimes inaccurately referred to as having a high aromatics content. Nomenclature aside, because of this, the burning characteristics of pyrolysis gas oil and pyrolysis pitch are poor. They are smoky, sooty, and gum formers they rend to be more viscous, and because of their polynuclear aromatic concent, they are suspected carcinogens. They are basically a witchs brew of unsavory hydrocarbons.. ... 

The purpose of hydrofining reactions may vary with the feedstock. Gasolines or coke-oven light oil are treated to remove gum formers, that is, readily polymerizing olefins and sulfur compounds, while hydrogenation of aromatics must be avoided. Hydrogenation of kerosenes and Diesel... 

Gums are used in industry because their aqueous solutions or dispersions possess suspending and stabilising properties. In addition, gums may produce gels or act as emulsifiers, adhesives, flocculants, binders, film formers, lubricants, or friction reducers, depending on the shape and chemical nature of the particular gum (2). Considerable research has been carried out to relate the stmeture and shape (conformation) of some gums to their solution properties (3,4). 

Locust bean gum and its derivatives are exceUent film formers and can be used either alone or in combination with starch as textile sizing agents and dye thickeners in textile printing, and as fiber bonding and beater additives in the papermaking industry. However, in most of these appHcations it has been replaced by guar. 

Natural Gums. These were used in early styling products, formerly called wave sets. Natural gums generally make hazy solutions and the dried film tends to flake. For these reasons they are rarely used. Some of these gums, eg, tragacanth and alginates, can create humidity-resistant films and have limited use for specific product concepts. 

Because the viscosity of neoprene latex at a given soHds content is less than that of natural mbber latex, thickeners are generally needed with the former. MethylceUulose and the water-soluble salts of poly(acryhc acid) are the two most commonly used thickeners. Natural and synthetic gums are also used. 

Extracellular material of a slimy or gelatinous nature is formed by many bacteria, especially those producing mucoid growths. This material may remain firmly adherent as a discrete covering layer on each cell, or it may part freely from the cells. In the former case it is known as a capsule in the latter, as free slime or gum. 

Besides widening the clinical use, the research on rifaximin is also focused on the synthesis of new derivatives [173, 273] and on the development of original formulations, like soft capsules [274] and a gum-like device [275], designed for the controlled and continuous release of rifaximin. The former preparation, being bioadhesive, could be particularly useful in the Helicobacter eradication from the stomach whereas the latter should make the treatment of infections of the oral cavity possible, thus expanding the spectrum of clinical use. 

Ernst et al. (2001b) 11 Smokers 11 former smokers >5o-PET/2-back Two pieces of 2-mg nic gum vs. placebo gum 1 ACC and PEC activation in smokers... 

Uses. May occur as an intermediate in the production of chlorinated ethylenes formerly used as a solvent for cellulose ethers, resins, and gums, for dry cleaning, coal purification, as a soil sterilizing agent, and as a chemical intermediate in the production of dichloroacetic acid... 

Description.—Gum-tragacanth, s wirite, yellowish, or yellowish-brown, and occurs either in moderately large, broad, thin pieces, marked with archod or concentric elevations—flaky tragacanth,—or in small, twisted, filiform, spil d fragments—vermiform tragacanth, The former is the kind usually found in this country, while the latter is common cn the Continent. 

Adulteration.—According to 8. H. Maltass, gum-tragacanth i b adulterated with two inferior gums. These, he says, are collected in Armenia and Cam-mania from various trees, principally wild almond and plum. That from the former locality is sent to Constantinople from Moussul, whence it takes the name of MowsouU. The Caramanion product is sant direct to Smyrna, and is termed Caraman. 

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