History of materials

Figure 2.9. The same x-t diagram as in the previous figure is used to illustrate histories of material as it flows past points Xi, X2, and X3.

Andrew Keller (1925-1999) who in 1957 found that the polymer polyethylene, in unbranched form, could be crystallised from solution, and at once recognised that the length of the average polymer molecule was much greater than the observed crystal thickness. He concluded that the polymer chains must fold back upon themselves, and because others refused to accept this plain necessity, Keller unwittingly launched one of the most bitter battles in the history of materials science. This is further treated in Chapter 8, Section 8.4.2. 

These compositional considerations necessitate attention to raw materials evaluation early in process research and development to (1) establish an in-depth knowledge of the principal raw material, including its composition and history of materials handling prior to arrival at the factory, (2) investigate the effects of seasonal variations and storage under various conditions on composition and on hydrolytic performance, and (3) explore alternative pretreatment processes for upgrading the composition and hydrolytic performance of available raw materials. The resource that is for sale is not pure cellulose it is a complex mixture containing cellulose caveat emptor. 

An institutional history of materials science is still to be done, and should be approached from an international perspective, in order to allow comparisons. In the French case, the pioneer was the Centre des materiaux of the National School of Mines in Paris (1967) and one of the most recent is the Institut des materiaux de Nantes created in 1988. 

Lessons may also be learned from applications of control systems in the food processing industries. These applications must satisfy hygiene requirements (including periodic cleaning and sterilization), time constraints imposed by product perishability, and requirements for accurate records of sources and operation histories of materials.21 The industry also experiences slim profit margins, short production runs, and frequent product changeovers—characteristics shared with many industrial bioprocesses. 

At the scale of thin sections, dissolution, cementation, and replacement are all prima facie evidence of elemental mobility. It is clear that late diagenesis involves complex history of material transfer at the scale of a few millimeters because detrital materials immediately adjacent to cements and grain replacements may show no evidence of dissolution, or contain no elements in common with the authigenic minerals. For minor elements that are concentrated in authigenic phases in amounts far in excess of their concentration in the bulk rock (e.g., barite cement), extraction from some relatively larger rock volume is necessary. 

Lange, F.A. 1925. The History of Materialism and Criticism of Its Present Importance. New York Harcourt. Latour, B. 1990. The Force and the Reason of Experiment. In LeGrand, H. (ed.), Experimental Inquiries. Dordrecht Kluwer, 49-80. 

This book presents a new history of material objects in general, and of eighteenth-century chemistry in particular. It interweaves three historical and philosophical themes ontologies of materials, practices of making, identifying and classifying materials, and the science of materials, from the late seventeenth century until the early nineteenth century. 

See Schummer [1997]. In the foUowing we use the term materials for all kinds of stuff that have been applied in industry and everyday consumption, and substances when we wish to highUght the scientific circumscription of these objects. For a philosophical history of materials from antiquity until the twentieth century see Bensaude-Vincent [1998]. 

Bucquet s detailed experimental histories of materials regarded as compound proximate principles of plants demonstrate impressively the diverse provenance of these substances, either firom chemical experiments in the chemical laboratory or from the world of trade and commerce. Many of his specific varieties of proximate principles of plants were imported commodities also described in the contemporary pharmacopoeias. For example, the class of extractive parts of plants (see figure 13.7) assembled various chemical extracts separated from plants in the laboratory by decoction and subsequent evaporation as well as juices prepared on a large scale in the trade, such as the juice of Hypocistis, juice of Acasia, and opium. Bucquet described not only the way to obtain the latter three pharmaceutical simplicia from... 

Linear polymers in the semi-crystalline state are metastable nanostructured systems with the complicated morphology, which are divided into nano-, submicro-, or microphases with crystalline, amorphous, and intermediate (mesophase and other) molecular packing. These different phases are connected in the flexible-chain polymers, such as PE, POM, poly(ethylene terephthalate) (PET), and many others, via strong covalent coupling between crystallites and disordered regions since the typical polymer molecules of l-lOOpm in contour length participate in several nanophases. Due to the multilevel structure, polymers with rather high levels of crystallinity may show up unique dynamics and properties which vary with the thermal and mechanical histories of materials. This has been confirmed by different techniques (DMA, DSC, NMR, DRS, and others) in numerous studies. 

Keywords History of chemistry History of materials Macromolecules Plastics Polymers... 

The characterization does not merely examine macro- and microscopic features of materials but clarifies the chemical composition and structure texture as factors reflecting material properties and functions in relation to the history of materials, i.e., raw material —> material handling production. The concept of characterization is illustrated in Fig. 2. The characteristics change dynamically in the functional state, which corresponds to status analysis instead of analysis in Fig. 2. 

History of materials (substrates, cleaning) The history of a material includes the specification of raw materials, fabrication techniques, storage times, environments, etc. In many cases the history of the material to be coated determines what must be done to clean or prepare the surface. In addition, changes in the history from lot to lot can be an unacceptable process variable. See also Outdiffusion Outgassing. 

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