Physical Traits

Characterization. The proper characterization of coUoids depends on the purposes for which the information is sought because the total description would be an enormous task (27). The foUowiag physical traits are among those to be considered size, shape, and morphology of the primary particles surface area number and size distribution of pores degree of crystallinity and polycrystaUinity defect concentration nature of internal and surface stresses and state of agglomeration (27). Chemical and phase composition are needed for complete characterization, including data on the purity of the bulk phase and the nature and quaHty of adsorbed surface films or impurities. 

Extrapolating from prior examples of group formation to future possibilities is a deductive process, and so it is perhaps not so unusual to bring Arthur Conan Doyle s Sherlock Holmes into the discussion. As devoted readers will testify, Conan Doyle s stories are filled with physical details, particularly those relating to the persons and behaviors of his characters. Some of those physical traits are immediately observable to other characters in the stories, whereas other physical traits are apparent only after their logical relation to human actions are made evident by Holmes. 

Everyday experience shows us that all human beings are unique in their external appearance and can be safely distinguished if only sufficient independent physical traits are compared. From so-called identical twins we learn that a considerable part of this phenotype is inherited. 

Over time, Mendel was able to hypothesize that some type of particle passed from parent to progeny was responsible for the physical traits expressed in subsequent generations. He even ascertained that each offspring receives two of these particles one from each parent. Mendel was able to lay down the basic foundations from which modern genetic theory has been built. These particles were later termed alleles. One allele is contributed by each parent and the two combined alleles determine the offspring s characteristics. 

Cladistics—The study of evolutionary relationships between organisms based on analysis of the similarities and differences of their physical traits, that is, based on evolutionary divergence. 

Even when used in reflection mode, NIR imaging will reveal much more information about the internal structure of products than will visible light. This is due to the fact that the diffusion coefficient is lower in NIR, and that the light is not altered by pigments at the surface of the commodity. This property is uhlized to determine the physical traits of a sample, or to reveal beneath-skin defects. 

This term refers to the characteristics which distinguish certain national and racial groups of people from others. Hence, ethnic characteristics may include social customs, food patterns, character and physical traits of the various peoples. 

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