LITER.~TURE
330 The measurement of the absorption of p-rays from Ca”5 was used as a technique for the inplace wear studies on flooring material. This procedure speeds up the process of evaluating the wear properties of such products by providing more accurate information resulting from less actual wear. Wear Testing Synthetic Floor with Diamond-bead Apparatus.
J. Zilles and I.. Paris, Ind. (1964) 20+-205. This paper compares test mond-head apparatus with other forms of equipment floorings.
Coverings
Diamond Rev., 24 results from diaresults from two on various PVC
Investigation of Wear of Polyamide Cogwheels by Dyeing. V. A. Belyi et al., Sov. Plastics {Lomdon), (8)
(1964) 66-67; 3 figs. A conventional dye for acetate silk was used to dye the surface to 0.2 mm depth and to follow the wear of polyamide cog wheels by observing changes in colour intensity. Experimental Techniques Sealing Face Seals,
in Testing
Liquid
0. E. Teichmann, L. A. Varga and E. J. Gyory, Lubrication Eng., 20 (9) (1964) 3455 35’ ; 8 figs. During an investigation of 2 in-diameter face seals sealing aqueous liquids under pressure from 100 to 2000 p.s.i. and running at speeds up to 3600 r.p.m. a cradled seal tester was developed that permits accurate measurement of seal torque. To determine from the torque reading the coefficient of friction between the mating surfaces, the closing force of a “zero balance” seal was measured as a function of seal pressure and interpreted in terms of coefficient of friction and pressure distribution between the seal faces.
AKDCURRENT
EVENTS
The Influence of Defects and Surface Structure on the Catalytic Activity of Silver Films.
J. Bagg, H. Jaeger and J. V. Sanders, J. CataZysis, 2 (6) (1963) 449-464; I 2 figs., 3 tables, 19 refs. Formic acid vapor has been decomposed catalytically to hydrogen and carbon dioxide on silver films of four types, differing in the concentrations of four types of defects and in surface structure. When the rate is expressed as A expj - ElIiT), values of A and E for the zero order reaction depend upon structural details. A and E change together to give an almost constant rate, i.e. compensation occurs. The concentrations of defects in the films have been determined by transmission electron microscopy, and the surface structure from replicas. It is concluded that points and lines of emergence of defects at the surface are unimportant, and that, with one possible exception, changes in values of A and E are related to the varying proportion of the surface which is flat and parallel to (III) planes. Decoration of Facets on Silver. J. G. Allpress and J. V. Sanders, PhiE. Mug.,
9 (100) (‘964) 645-658; IO figs., zo refs. The facets produced on silver by thermal etching have been investigated in detail by examining decorated replicas of them in an electron microscope. Gold, condensed on the surface in vacuum, forms perfectly oriented sheets on the complex facets which contain many kink atoms. By contrast, the gold condenses on ( IOO)and (I I I) planes as separated, randomly-distributed crystals with some preferred orientations. Atomic steps on these planes are decorated by preferential nucleation. A Statistical Polyhedron Model Grain. H. T. McPldams, Tralzs. ASME,
of Abrasive
85 D (1963)
388.--394. (f. E%g. Porter, 4f 7. SURFACE PROPERTIES AND TREATMENT
SURFACE
Relationship between Reactivity and Structure of Metallic Surfaces. J. V. Sanders, J. Australian Inst. Met&, 9 (2) (1964) 63-70; r7 figs., I tabfe, 21 refs. The core of the problem of relating the reactivity to the structure of surfaces is to prepare a clean, well-defined surface on a solid metal. The structures of surfaces prepared by a variety of laboratory processes are described. It is argued that films, prepared by evaporation under clean vacuum conditions, are the most suitable specimens, and it is shown how their structure can be systematically varied for a given metal. The catalytic activity of such films is found to depend upon the physical structure of the surface. Wear, 8 (1965) 320-331
Wire Brush Polishing. Yu. G. Proskuryakov and V. A. Kulikovskikh, Russ. Eng. /. (Translation of vest. Mashinostr., 43 (a) (1963) 5658 by Production Engineering Research Association of Gt. Britain.) For abstract see .4ppI. Mech. Rev.. 17 (8) (I 964) 606. Contributions to Basic Research on ACCUmulation, Adhesion, and Cleaning of Dirt of Rail of Lacquered Outer Surfaces Vehicles: Parts 1, 2 and 3. (In German) H. Reumuth, Glasers Ann., 85 (7) (Ig6r) 221-235; 86 (3) (rg6z) 7-80; 86 (9) (r962) 365-378. For abstract see a4ppZ. Mech. Rev., 17 (8) (1964) 617.