Nonfibrous

Asphalt aluminum roof coating (nonfibrated). Asphalt aluminum roof coating (fibrated)... 

Type II, fibrated lap cement (asbestos) Type III, fibrated lap cement (nonasbestos) Type I, nonfibrated... 

The two main amphibole asbestos fibers are amosite and crocidoHte, and both are hydrated siHcates of iron, magnesium, and sodium. The appearance of these fibers and of the corresponding nonfibrous amphiboles is shown in Figure 1. Although the macroscopic visual aspect of clusters of various types of asbestos fibers is similar, significant differences between chrysotile and amphiboles appear at the microscopic level. Under the electron microscope, chrysotile fibers are seen as clusters of fibrils, often entangled, suggesting loosely bonded, flexible fibrils (Fig. 2a). Amphibole fibers, on the other hand, usually appear as individual needles with a crystalline aspect (Fig. 2b). 

In contrast to chrysotile fibers, the atomic crystal stmcture of amphiboles does not inherentiy lead to fiber formation. The formation of asbestiform amphiboles must result from multiple nucleation and specific growth conditions. Also, whereas the difference between asbestiform and massive amphibole minerals is obvious on the macroscopic scale, the crystalline stmctures of the two varieties do not exhibit substantial differences. Nonfibrous amphiboles also exhibit preferential cleavage directions, yielding fiber-shaped fragments. 

Nonfibrous Reinforcements. Because of the higher costs associated with nonasbestos fibers and the performance requirements needed in replacing asbestos, platy minerals such as mica and talc, and metal powders such as iron and copper, are being used as a portion of the total reinforcement package in NAOs. 

In order to define the extent of emissions from automotive brakes and clutches, a study was carried out in which specially designed wear debris collectors were built for the dmm brake, the disk brake, and the clutch of a popular U.S. vehicle (1). The vehicle was driven through various test cycles to determine the extent and type of brake emissions generated under all driving conditions. Typical original equipment and aftermarket friction materials were evaluated. Brake relines were made to simulate consumer practices. The wear debris was analyzed by a combination of optical and electron microscopy to ascertain the asbestos content and its particle size distribution. It was found that more than 99.7% of the asbestos was converted to a nonfibrous form and... 

Reinforced plastics (RPs) hold a special place in the design and manufacturing industry because they are unique materials (Figs. 6-11 and 6-12). During the 1940s, RPs (or low-pressure laminates, as they were then commonly known) was easy to identify. The basic definition then, as now, is simply that of a plastic reinforced with either a fibrous or nonfibrous material. TSs such as polyester (Table 6-19) and E-glass fiber dominated and still dominates the field. Also used are epoxies. 

Hansen, K. and Mossman, B.T. (1987). Generation of superoxide (Oi ) from alveolar macrophages exposed to asbestiform and nonfibrous particles. Cancer Res. 47, 1681-1686. 

Intracellular space Fibrous protein ( 65-70%), nonfibrous (soluble) protein ( 5-10%) 75... 

Simply put, paper is manufactured by applying a watery suspension of cellulose fibers to a screen that allows the water to drain and leaves the fibrous particles behind in a web. Most modem paper products contain nonfibrous additives, but otherwise they fall within this general definition. Only a few paper products for specialized uses are created without the use of water, using dry forming techniques. The production of pulp is the major source of environmental impacts from the pulp and paper industry. 

Oberdorster, G. (2002) Toxicokinetics and effects offibrous and nonfibrous particles. Inhalation Toxicology, 14 (1), 29—56. Warheit, D.B. (2006) What is currently known about the health risks related to carbon nanotube exposures Carbon,... 

Asbestos is a nonspecific, collective term for a group of fibrous minerals. A sample called asbestos may be composed of one or more of the six minerals listed above and may contain small amounts of other nonfibrous silicate minerals, such as quartz, feldspar, or mica. The definition of asbestos recently published by the American Society for Testing Materials (Ross et al., 1984) can be found in the Glossary. 

Campbell, W. J., C. W. Huggins, and A. G. Wylie. Chemical and physical characterization of amosite, chrysotile, crocidolite, and nonfibrous tremolite for oral ingestion studies by the National Institute of Environmental Health Services. Bureau of Mines RI. 8452. U.S. Department of the Interior, Report of Investigations. Washington, D.C. 

Toxicology. The toxicity of calcium silicate depends on particle size, aspect ratio, and amount of silica and respirable fiber. Synthetic nonfibrous calcium silicate is considered to be a nuisance dust. 

Synonyms Mica is a nonfibrous silicate occurring in plate form and includes nine different species muscovite is a hydrated aluminum potassium silicate also called white mica phlo-gopite is an aluminum potassium magnesium silicate also called amber mica other forms are biotite, lepidolite, zinnwaldite, and roscoelite... 

Toxieology. The nonasbestos form of talc, also termed nonfibrous or pure talc, has not been proven to cause the effects produced by exposure to fibrous talc, namely, fibrotic pneumoconiosis and an increased incidence of cancer of the lungs and pleura. 

In a study of 20 workers exposed for IQ-36 years to talc described as pure, at levels ranging from 15 to 35mppcf, no evidence of pneumoconiosis was found. In another study that compared the pulmonary function of workers exposed to either fibrous or nonfibrous talc, it was concluded that although the fibrous form was the more pathogenic type, both talcs produced pulmonary fibrosis no data were presented to document the types of talc involved." ... 

A study of 260 workers with 15 or more years of exposure to commercial talc dust (containing not only talc, but also tremolite, antho-phyllite, carbonate dusts, and a small amount of free silica) revealed a 40-fold greater than expected proportional mortality from cancer of the lungs and pleura. In addition, a major cause of death was cor pulmonale, a result of the pneumoconiosis the effects were likely due to the asbestos-form contaminants. The role of nonfibrous talc in these disease states could not be assessed. 

The bark of trees contains relatively little fiber and much strongly colored nonfibrous material what fiber there is, is of poor quality. The nonfibrous material usually will appear as dark-colored dirt specks in the finished paper. Therefore, for all but low-grade pulps, bark should be removed as thoroughly as possible, and this removal must be very thorough in the case of groundwood and sulfite pulps if the finished paper is to appear clean. 

Nonfibrous reinforcements are also employed as reinforcements and fillers. They result in increased tensile strength and deflecdon temperature, but usually decrease impact resistance. Nonfibrous reinforcements are preferred when fabricating with exceptional flatness. The nonfibrous include mica, glass beads, and minerals such as wollastonite (talc, calcium carbonate, and kaolin are considered fillers). Unlike fibrous reinforcements the nonfibrous reinforcements can be processed by many different technologies. 

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