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ABSTRACTS

cycles in which the maximum load in any given cycle exceeded the maximum load of the preceding cycle. These changes were also found to be greater for the rougher surfaces. The experimental results are interpreted in terms of the resistance to rolling being dependent on two factors; (a) the hysteresis loss concept, and (b) the requirement for the smooth roller to surmount the irregularities on the surface.

extended to cover a wider range of experimental conditions than previously. A new deformation index 7 is suggested additional to the normal index. q appears to determine the real area of contact between surfaces and is a function of the change in the distribution of asperity contacts with pressure over the region of contact. The value of q depends on whether the number of asperity contacts per unit indentation area increase (17positive) remain constant (r] zero) or decrease (q negative) with increasing pressure. Maximum and minimum 7 values occur owing to the existence of two opposite limits in the geometrical conditions between the surfaces within the indentation area.

Theory of Friction of Polymers. J. D. Huffington. The British Jute Trade Research Association. Research, v. 12, 1959, p. 443-446; 5 fig, 6 ref. The multiple junction theory of friction is 3. LUBRICATION 3. I. Lubrication A Gas Film Lubrication Study. I. Some Theoretical Analyses of Slider Bearings. II. Numerical Solution of the Reynolds Equation for Finite Slider Bearings. III. Experimental Investigation of Pivoted Slider Bearings. I. W. A. Gross. II. W. A. Michael. III. R. K. Brunner, J. M. Harker, K. E. Haughton, and A. G. Osterlund. IBM Journal of Research and Development, V. 3, no. 3, July 1959, p. 237-274. Important characteristics of such films are determined directly from the Reynolds equation. Pressure, load, velocity, and geometry characteristics are presented for many compressible slider bearing films based upon computer solutions of a Reynolds difference equation. Cites experimental verification of computer solutions and describes experimental techniques. A The.ory of Oil Whip. Yukio Hori. ASME, Transactions, Series E, Journal of Applied Mechanics, V. 26, no. 2, June 1959, p. [email protected] Oil whip was investigated theoretically and experimentally. It is shown that the inherent instability of the rotor in previous theories can be avoided by assuming zero pressure in place of negative pressure in the oil film and that the “inertia effect” in occurrences of oil whip can be understood by distinguishing small vibrations and large vibrations of the rotor. On the Effect of Lubricant Inertia in the Theory of Hydrodynamic Lubrication. A. A. Milne. ASME, Transactions, Series D. Journal of Basic Engineering, v. 81, no. 2, June 1959, P. 239-244. A theoretical study is made of the corrections required to the basic lubrication equations $0 allow for small effects of lubricant inertia in the laminar regime .The problem is approached by first determining the stream function

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LUBRICANTS

for a wedge-shaped oil film with purely viscous flow and then obtaining the first-order correction for inertia. The effect of lubricant inertia is to cause a slight increase in the load capacity of a bearing. Theoretical Criteria for the Effectiveness of a Lubricant Film. E. Rabinowicz. ASLE Transactions, V. I, no. I, 1958, p. 96; 7 fig., 18 ref. For lubricated surfaces, it is shown that only lubricants made up of very small molecules can be energetically stable on hard metal surfaces, and hence successful lubricants must form solid surface films. At the melting point of the lubricant film a transition takes place and the lubricant loses much of its effectiveness, while a second transition occurs at a higher temperature and leads to galling. Some Considerations Relating to Lubrication of Aircraft Turbine Engines. Alfred B. Two. Lubrication Engineering, v. 15, July 1959, p. 280-285. Describes requirement of present-day aircraft engines and discusses lubricants which are currently being used. The Lubrication of Turbine Gearing. G. H. Clark. Scientific Lubrication, V. I I, June 1959, p. I2 + 8 pages. Discusses “K” factor, scuffing, types of gear failure, pitting, tooth fracture, importance of good surface finish, and gear steels. 3.2. Liquid

lubricants

Lubricating Oils and Greases in the Soviet Union. N. Cheremeteff. Engineer Research and Development Laboratories, U.S. Army. May 1958. 114 pp. (Order PB 151294 from OTS, U.S. Department of Commerce, Washington 25. D.C., $2.50.) Recent Soviet developments in the field of lubricants are reviewed in this comprehensive Wear, 3 (1960) 155