Wood samples, relationship

Figure 4. Relationship of radiocarbon and dendrochronological age of wood samples (after Ralph et...

Lord Kelvin s close associate, the expert experimentalist J. P. Joule, set about to test the former s theoretical relationship and in 1859 published an extensive paper on the thermoelastic properties of various solids—metals, woods of different kinds, and, most prominent of all, natural rubber. In the half century between Gough and Joule not only was a suitable theoretical formula made available through establishment of the second law of thermodynamics, but as a result of the discovery of vulcanization (Goodyear, 1839) Joule had at his disposal a more perfectly elastic substance, vulcanized rubber, and most of his experiments were carried out on samples which had been vulcanized. He confirmed Gough s first two observations but contested the third. On stretching vulcanized rubber to twice its initial length. Joule ob-... 

The relationship of modern wine styles to aging wines in wooden barrels is described. The physical and chemical characteristics of different woods lead to the conclusion that white oak is best for wine cooperage. European cooperage oak samples had 161% of the extractable solids of North American samples and 154% of the phenol per unit of extractable solids, but American oak contributed more oak flavor to wine per unit of extract. Data are presented on the density and extractable phenol content of summer and spring oak wood, the characteristics of rapidly vs. slowly grown oak, the surface per unit volume effects of container size and shape, the variability among trees in flavor and extract content, the analysis of wood extract in wine, and the depth of penetration of wine into staves. 

Figure 16 Relationship between the sulfonate and phenolic hydroxyl group content of sulfonated wood meal samples. (From Ref. 408.)...

These studies were later extended to the ignition of specially prepared cellulose sheets" as a model for the broad class of kindling fuels. These sheets were made from a single batch of wood a-cellu-lose, with various proportions of carbon black added to provide a variation in optical properties from white to black. The thickness of the sheet varied within the range of 0.002 to 0.03". Furthermore, the samples were prepared in two densities, which gave two different sets of heat-conduction properties. Thus, the experimental samples had the same chemical properties but a considerable latitude for variation in physical properties. The samples were exposed to constant thermal radiation at levels of 2—23 cal.cm. sec. , to establish the relationship between the threshold of ignition (with the exposure parameter) and the fuel properties. 

Coal Tar Products. In an industrial health survey of employees in a wood preservative plant in which coal tar creosote, coal tar, and pentachlorophenol were the main treatments used, cardiovascular effects, including increased diastolic blood pressure, were noted in 21% (24 of 113) of the employees examined (TOMA 1979). Industrial hygiene surveys of coal tar pitch volatiles at this and three other wood preservative plants indicated that airborne exposure to benzene-soluble components of the coal tar pitch volatiles was within the OSHA permissible limit of 0.2 mg/m3 in 94% of the samples (TOMA 1979). The other 6% of the samples ranged from 0.21 to 3.6 mg/m3 (TOMA 1979). Nevertheless, no clear relationship could be established because exposure routes in addition to inhalation (e.g., oral and dermal) were likely. Also, the ability to relate cardiovascular effects to coal tar creosote and coal tar exposure was further confounded by the possibility that the subjects were also exposed to other chemicals including pentachlorophenol and cigarette smoke (TOMA 1979). Additional limitations of the study are noted above (see "Respiratory Effects"). However, in another industrial study, an increase in mortality from... 

One of the major simplifications adopted in chemistry is to focus on substances. This is a simplification because, in our normal environment, few of the materials we commonly come across are stricdy substances in the chemical sense. Figure 1.1 sets out the relationship between some key ideas in chemistry. So where matter is a general term for stuff, we tend to use the term materials for well defined samples of stuff that we can work with - glass, wood, sodium carbonate (washing soda), poly(ethene), diamond, sea water, paint, etc. From a technological perspective, these materials may have a similar status (different types of stuff that can be obtained, worked in various ways or used in different applications). 

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