Uniformity, of nature

There are several systems that define the quality and uniformity of natural mbber. One system of grading natural mbber is based on form and visual observation of color and cleanliness. This is known as the International Natural Rubber Specification. The principal types and grades are as follows. There are five other types of mbber classified by this system and many other grades not Hsted here. 

The corner stone of nineteenth century physics was the idea of the uniformity of nature that identical causes always produce identical effects. This idea was expressed by Clerk-Maxwell in the following words ... 

We are not now in a position to support any such dogmatic statement as that of Clerk-Maxwell. The idea of the uniformity of nature was based on superficial observations of large scale phenomena, and it now appears that with given initial conditions many future events are possible. At best all we can hope to do is to calculate the relative probabilities or chances of th.e different possible events. Also Clerk-Maxwell s statement involves the assumption that it is possible to fix the initial configuration and motion of the bodies concerned exactly, and as we shall see this is not the case. 

Although he thinks that Hume was half-right . Sober thinks Hume made a mistake in thinking that there is a single missing premise shared by all inductive inferences and that this premise is that nature is uniform. Most contemporary philosophers of science agree that Hume s notion that nature is uniform is too vague to be of much use in induction, for it is clear that we do not think that nature is uniform in all respects. Thus Hume s claim that induction presupposes the uniformity of nature is... 

The uniformity of fibers affects the properties and quality of end-products. The strength of an individual fiber is determined by its weakest point. For synthetic polymer fibers, man-made inorganic fibers and nanofibers, the uniformity can be controlled during the fiber formation process to minimize the stmctural irregularities. However, it is difficult to control the uniformity of natural fibers since the structure of these fibers is affected by many environmental factors. Although the uniformity of an individual natural fiber is uncontrollable, it is possible to improve the overall uniformity of fibers in end-products by blending natural fibers from many different batches. 

Various methods of home-dyeing cotton and wool materials using natural dyes made from hulls of butternut, hickory nut, pecan, eastern black walnut, and Knglish walnut have been described (149). As far back as during the Civil War, butternut hulls have been used to furnish the yellow dye for uniforms of the Confederate troops. More recent attempts have been made to manufacture yellow and brown dyes from filbert shells on a commercial scale. The hulls are treated with copper sulfate and concentrated nitric acid to produce a yellow color, with ferrous sulfate to produce oHve-green, or with ammonia to produce mby-red (150) (see Dyes AND DYE INTERMEDIATES Dyes, natural). 

Compared with the natural material, raw SBR is more uniform in a variety of ways. Not only is it more uniform in quality so that compounds are more consistent in both processing and product properties but it is also more uniform in the sense that it usually contains fewer undesired contaminants. In addition, over a period of years it has been generally less subject to large price variations. These differences in uniformity have, however, tended to lessen with the advent of improved grades of natural rubber such as Standard Malaysian Rubber which have appeared in recent years. 

All of the structures shown in Figures 7.2 and 7.3 are D-configurations, and the D-forms of monosaccharides predominate in nature, just as L-amino acids do. These preferences, established in apparently random choices early in evolution, persist uniformly in nature because of the stereospecificity of the enzymes that synthesize and metabolize these small molecules. 

The reason for this varied behaviour is not difficult to find. A population of bacteria does not possess the uniformity of properties inherent in pure chemical substances. This fact, together with the varied manner in which bactericides exert their effect and the complex nature of the bacterial cell, should provide adequate and satisfying reasons why the precise theories of reaction kinetics should have failed to explain the disinfeclion process. 

The purpose of scouring is to reduce to an acceptable level the amounts of fats, waxes, oils and dirt present. Apart from the aesthetic benefits of a clean substrate, the major technical reason for scouring is to improve the extent and uniformity of absorbency for subsequent processes, especially coloration. Usually the objective is the complete removal of all extraneous matter but on occasion only partial removal is the aim, since a certain residue of oils, for example, will aid such processes as spinning, weaving or knitting. Scouring is particularly important with natural fibres, which obviously contain much more extraneous matter than do synthetic fibres. 

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