Finance pay-back period

The Indian-born physicist Subramanyan Chandrasekhar (Nobel Prize 1983) had a personal style of research, which 1 learned about only recently, that seems to parallel mine. He intensely studied a selected subject for years. At the end of this period he generally summarized his work and thoughts in a book or a comprehensive review and then moved on to something else. He also refuted Huxley s claim that scientists over 60 do more harm than good by sharing the response of Rayleigh (who was 67 at the time) that this may be the case if they only undertake to criticize the work of younger men (women were not yet mentioned) but not when they stick to the things they are competent in. He manifested this belief in his seminal work on black holes, on which he published a fundamental book when he was 72, and his detailed analysis of Newton s famous Principia published when he was 84, shortly before his death. I have also written books and reviews whenever I felt that I had sufficiently explored a field in my research and it was time to move on this indeed closely resembles Chandrasekhar s approach (vide infra).  [c.227]

Creep Feed Wheels. Abrasive machining in which the grinding wheel does not merely finish the surface of a machine part but actuaHy forms it by removing a significant amount of metal is a relatively new grinding procedure caHed creep feed grinding. In this process, a shape is generated in the face of an open-stmcture vitrified grinding wheel by diamond tooling or cmsh-form roHer. The profiled wheel is then fed into the metal to be ground in a deep cut, ranging from 1 to 10 mm, at a very slow rate under a flood of coolant. In normal grinding, cuts are shaHow, from 0.025 to 0.13 mm, and formed at a fast travel rate. Creep feed grinding finds its greatest use in the aerospace industry where hard-to-grind, heat-resistant aHoy parts must be ground without surface damage. The intricate "Christmas tree" shape at the base of a turbine blade can be ground in one pass using this process and there is less wheel wear, better retention of form, and higher overaH productivity than with other shaping methods. Reference 46 provides a complete treatment of the creep feed grinding process.  [c.15]

Single-Effect Evaporators Single-effect evaporators are used when the required capacity is small, steam is cheap, the material is so corrosive that very expensive materials of construction are required, or the vapor is so contaminated that it cannot be reused. Single-effect evaporators may be operated in batch, semibatch, or continuous-batch modes or continuously. Stric tly speaking, batch evaporators are ones in which filling, evaporating, and emptying are consecutive steps. This method of operation is rarely used since it requires that the body be large enough to hold the entire charge of feed and the heating element be placed low enough so as not to be uncovered when the volume is reduced to that of the product. The more usual method of operation is semibatch, in which feed is continually added to maintain a constant level until the entire charge reaches final density. Continuous-batch evaporators usually have a continuous feed and, over at least part of the cycle, a continuous discharge. One method of operation is to circulate from a storage tank to the evaporator and back until the entire tank is up to desired concentration and then finish in batches. Continuous evaporators have essentially continuous feed and discharge, and concentrations of both feed and product remain substantially constant.  [c.1143]

If an elastic or insufficiently hard primer or paint has been applied under a less elastic top coat, or if the first coat (or set of coats) of oil-base paint has been second-coated before it is completely dry, not only will the paintwork remain soft for an unduly fong period, but cracking will also follow, as the upper layer cannot follow the movement. If the last coat is very thick this fault will frequently manifest itself in the form of alligatoring, i.e. the formation of cracks which do not penetrate all the films down to the substrate, and which may be present in the top layer only.  [c.615]

The use of phosphate coatings for protecting steel surfaces has been known for over 60 years, and during this period commercial utilisation has steadily increased until today the greater part of the world production of motorcars, bicycles, refrigerators, washing machines, office furniture, etc. is treated in this way. By far the greatest use of phosphate coatings is as a base for paint, although other important applications are in conjunction with oil, grease, wax and spirit stains to provide a corrosion-resistant finish, with soaps to assist the drawing and pressing of steel, and with lubricating oil to decrease the wear and fretting of sliding parts such as piston rings, tappets and gears.  [c.706]

See pages that mention the term Finance pay-back period : [c.547]    [c.385]    [c.134]    [c.239]   
Plant Engineer's Handbook (2001) -- [ c.1108 ]