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FOR most of the uses to which timber is put, reasonably good resistance to impact is an advantage; for many uses, such as aircraft construction, sports goods, or tool…
FOR most of the uses to which timber is put, reasonably good resistance to impact is an advantage; for many uses, such as aircraft construction, sports goods, or tool handles, it is an overriding requisite. Its measurement is, therefore, an important part of the routine testing of timber. Since conditions of service as regards this property are seldom, if ever, known with exactitude, and since, moreover, the size and shape of the member receiving the impact bear an important but undefined relationship to its resistance, the laboratory tests for the property are essentially empirical. The resulting figures from such tests in themselves mean little; they cannot be translated into design figures as are, for instance, modulus of elasticity or maximum compressive strength; and their value lies almost entirely in their use for comparisons. As with most empirical tests, one of the essentials is that the character of the test, i.e. test‐piece and testing conditions, shall be rigidly defined and adhered to. Unfortunately there are in more or less common use in the various timber testing laboratories several different methods of measuring impact resistance and the lack of a universal standard impact test is a serious drawback to the usefulness of the results, since one of the greatest advantages of the standardized test, viz., the interchange‐ability of results between one laboratory and another, is at once nullified. It is hoped that when circumstances permit the interested research institutions will take up the study of impact testing and agree upon a uniform standard test.
COMPRESSED laminated (“ improved ”) wood is generally counted among the hardening laminated plastics; it is built up from a large number of very thin veneers (0.0–1.005…
COMPRESSED laminated (“ improved ”) wood is generally counted among the hardening laminated plastics; it is built up from a large number of very thin veneers (0.0–1.005 in.) which are arranged with parallel grain directions. With the use of thermosetting synthetic resins, the veneers are highly compressed between hot platens. The adhesive, normally of the Bakelite type, is also a strengthening agent, or, with material of high resin content and high density, the wood may be considered as more or less a carrier for the resin, the latter being in this case the main strength‐producing agent.
The present crisis in the global economy is more serious than anything that we have witnessed since the 1930s, yet policies designed to tackle it are limited and…
The present crisis in the global economy is more serious than anything that we have witnessed since the 1930s, yet policies designed to tackle it are limited and inadequate. Those that have been proposed, in terms of fiscal stimulus, rely on an outmoded view of the economy, where money can be used to force economic growth. Since the recognition of planetary limits such a strategy is no longer admissible. Instead, we need a global system where countries agree to limit their carbon dioxide emissions: this chapter outlines the Contraction and Convergence model (C&C), which proposes that countries do this within a framework of equal per capita emissions for all global citizens. However, within the existing financial architecture such a policy would do nothing to prevent the United States from continuing to print dollars and to use these to gain an unfair share of world production. Other countries controlling reserve currencies would also be able to avoid strict limits. The policy answer proposed is that of the Ebcu (environment-backed currency unit) – a neutral global trading currency to be used by countries that have also signed up to the C&C model.