Core prints

Where cores are to be incorporated in a casting (see section 15.3.3), provision must be made on the pattern to provide a location seating in the mould. These sections added to the pattern are known as core prints. 

When a casting is to have a hollow section, a core must be incorporated into the mould. Cores can be made from metal or more commonly from sand, made separately in a core box, and inserted into the mould after the pattern is removed and before the mould is closed. They are located and supported in the mould in a seating formed by the core prints on the pattern. The core must be strong enough to support itself and withstand the flow of molten metal, and in some cases it may be necessary to reinforce it with wires to give added strength. The more complex cores are produced from CO sand. 

Students and instructors). Each chapter presents first the basic surface chemistry of the topic, with optional material in small print. Derivations are generally given in full and this core material is reinforced by means of problems at the end of the chapter. A solutions manual is available to instructors. It is assumed that students have completed the usual undergraduate year course in physical chemistry. As a text for an advanced course, the basic material is referenced to fundamental, historical sources, and to contemporary ones where new advances have been incorporated. There are numerous examples and data drawn from both the older and from current literature. 

GORE. The CORE Electronic Chemistry Library is a joint project of Cornell University, OCLC (On-line Computer Library Center), Bell Communications Research (Bellcore), and the American Chemical Society. The CORE database will contain the full text of American Chemical Society Journals from 1980, associated information from Chemical Abstracts Service, and selected reference texts. It will provide machine-readable text that can be searched and displayed, graphical representations of equations and figures, and full-page document images. The project will examine the performance obtained by the use of a traditional printed index as compared with a hypertext system (SUPERBOOK) and a document retrieval system (Pixlook) (6,116). 

However, conductive elastomers have only ca <10 of the conductivity of soHd metals. Also, the contact resistance of elastomers changes with time when they are compressed. Therefore, elastomers are not used where significant currents must be carried or when low or stable resistance is required. Typical apphcations, which require a high density of contacts and easy disassembly for servicing, include connection between Hquid crystal display panels (see Liquid crystals) and between printed circuit boards in watches. Another type of elastomeric contact has a nonconducting silicone mbber core around which is wrapped metalized contacts that are separated from each other by insulating areas (25). A newer material has closely spaced strings of small spherical metal particles in contact, or fine soHd wires, which are oriented in the elastomer so that electrical conduction occurs only in the Z direction (26). 

Decorative laminates have a core or base of Kraft paper impregnated with a phenolic resin. A printed pattern layer impregnated with a melamine-formaldehyde or urea-thiourea-formaldehyde resin is then laid on the core and on top of this a melamine resin-impregnated protective translucent outer sheet. The assembly is then cured at 125-150°C in multi-daylight presses in the usual way. 

Honeycomb core. Honeycomb core used for aluminum bonded sandwich structure is exclusively aluminum. The core is fabricated by printing offset stripes of adhesive (the node adhesive) on aluminum foil, stacking a large number of these foils and then curing the adhesive in a heated press. The resulting block is called a hobe. Slices are machined from the edge of the hobe and then expanded to... 

Fig. 6. Purified recombinant HMGA proteins bind to four regions of DNA on random sequence nucleosome core particles. Panel A The results of EMSA gel assays in which increasing concentrations of either purified nonhistone HMGN2 (a.k.a., HMG-17, which binds to two sites on nucleosome core particles) or recombinant human HMGAla protein were bound nucleosome core particles isolated from chicken erythrocytes [57]. Panel B Two different views of the nucleosome taken from the X-ray structure of Luger et al. [119] showing the sites of binding of HMGA proteins (dashed circles) determined by DNA foot-printing analyses and other techniques (see text for details).

CQR Resource Center offers the best resources available in print and online to help you study and review the core concepts of chemistry. 

This chapter has touched upon only a few of the core chemical industries petroleum refining, rubber, plastics, and textiles. A comprehensive review of the chemical industry would include agrochemicals, glass, pharmaceuticals, paper, metals, photography, brewing, cement, ceramics, printing, and paints. As the twenty-first century unfolds, the chemical industry will continue to play a dominant role in dictating our quality of life. The core... 

Figure 10.4 Lipid globule in human milk surrounded by a membrane which has a typical unit or bilayer appearance. This membrane is separated from the globule core by a layer of intensely stained coat material. The material on the outer face of the membrane has an appearance typical of the glycocalyx observed on plasma membranes, (b) A higher magnification of a region of membrane of the lipid globule shown in (a). Note that in certain regions a bilayer-like membrane is indiscernible. Bars = 0.1/im, magnification" (a) x 75,000, (b) x 137,000. Prints are of a micrograph published previously (Freudenstein et al. 1979) and are included with permission of Academic Press, Inc.

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