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THE adaptation and application of the cumulative experience of practical and theoretical research to the problems of industry has led to the solving of many of its problems and the linking up of industries of very diverse natures. Materials, processes, and mechanisms have been developed in many instances to an almost perfected state, leading to an economy in power consumption, reduced production costs, greater efficiency of the unit, and increased service life. Yet the protection of materials, particularly metals, employed in industry has not revealed itself to the same extent, more because of the enormity of the field of application than lack of development in this direction.

PROBABLY one of the most remarkable features of our generation has been the ability of the metallurgist to produce alloys meeting the current needs of industry in providing the requisite mechanical characteristics, capabilities of being manipulated or fashioned by established methods, and in particular instances, specific properties of resistance to erosion, corrosion, wear, impact and fatigue. Perhaps this adaptability is best exemplified in the case of light alloys, whereby scientific alloying of aluminium or magnesium bases with other elements, combined with specific thermal treatments, have imparted increased strength, durability, and, under limited conditions, resistance to corrosion, to a whole range of alloys without any appreciable sacrifice of the great advantage in initial lightness of these two base metals. In view of this, these metals, which are conveniently designated “light alloys,” have become exceedingly popular, particularly since the majority of them are eminently suitable for fabrication in the form of diecastings, which permit the reproducibility of exact forms in large quantity production. The mechanical features of light alloys, together with their capacity to be machined, or otherwise finished to shape and dimensions, are fairly widely known, but their ability and relative merits to resist various conditions of corrosive influence are not so clearly elucidated. The readers of this journal arc naturally concerned primarily with finishes of protective value rather than with those of decorative importance. In general engineering considerable confusion exists as to the behaviour of aluminium and its alloys under deleterious influences, and this tends to retard their general adoption, even though their individual mechanical properties may make them highly desirable. In some cases most unnecessarily elaborate finishes are applied for ultra precautionary purposes, while in others a complete ban is exercised rather than incur any risk. In the aircraft industry, on the other hand, the demand for minimum weight consistent with requisite strength has provided the impetus for their adoption, which in turn has led to the development of appropriate finishing methods. Even in this sphere a comparative survey of finishing methods and their efficiency covering a range of popular alloys should prove to be of interest.

Fig. 6 depicts the structural effects of tempering by heating for thirty minutes at 630 cleg. C., followed by cooling off in the furnace subsequent to the hardening treatment shown in No. 4. The reduced hardness is 190 V.P.N. This tempering treatment permits the transformation of the beta into alpha plus delta in such a manner that the hard delta constituent is evenly distributed throughout the mass. Thus a hard constituent is embedded in a soft matrix and this offers an excellent abrasion‐resisting material, together with considerable toughness. Higher magnification would show that the delta has commenced to spherodise, thereby preventing the growth of a lamellar structure, and reducing the possibility of fragility along the delta planes.

THE demands of modern engineering employing machinery that has to operate at high power, and to include rapidly‐moving units, has forced the metallurgist to depart from the old‐established alloys and to introduce new mixtures to which it is possible to impart specific or enhanced properties by thermal treatments. This aspect of metallurgy has also been given impetus by the demand for reliability, whether in factory plant or the fabricated product. This becomes obvious when it is realised, on the one hand, that the basis of all systemised workshops is the maintenance of continuity in output and an ever‐increasing production; and, on the other, that the failure of even a minor accessory may cause disaster with loss of material, labour or human life. Thus, it no longer occurs that one regards the ferrous metals only as being manipulable by selected heat treatments, and, in the non‐ferrous scries, annealing to be the only means of modification by heat. To‐day, various copper‐rich alloys are available that are susceptible to hardening and tempering processes closely similar to those long since employed for steels. Those containing beryllium and aluminium have been the most exploited. However, the reluctance with which the engineer accepts the advantages offered by these developments is understandable, because the information appertaining to the subject is not always available in a form which enables him to appreciate the economies to be accrued. Further, he often prefers production to be straightforward, using raw materials in the “as‐received” condition, rather than to introduce processes, the value of which has not been elucidated. Yet this is a situation that cannot be tolerated indefinitely, if economies in material weights and dimensions and increased service life are mutually to be secured. It is, therefore, from this angle that the study and comprehension of the properties and possibilities of aluminium bronze cannot be ignored.

TO those who are interested in the manufacture of articles for use in engineering workshops from the chemical standpoint, there is often very little sound practical knowledge to provide a link between their side of the proposition and the actual working requirements involved.

This study aims to examine the impact of the informational value of feedback choices (confirmatory versus critical feedback) on students’ performance, their choice to revise and the time they spend designing posters and reading feedback in a computer-based assessment game, Posterlet.

An empirical correlational study was conducted to collect the choices to seek confirmatory or critical feedback and to revise posters in a poster design task from 106 grade 8 students from a middle school in California via Posterlet.

The results of the study show that critical uninformative feedback is associated with students’ performance, and critical informative feedback is associated with their learning strategies (i.e. feedback dwell time and willingness to revise), while confirmatory informative feedback is negatively associated with both performance and learning strategies.

The study controlled the choice students were given regarding the valence of their feedback but not regarding the informational value of their feedback. Additionally, the study was conducted with middle-school students, and more research is needed to ascertain whether the results generalize to other populations.

The findings can be used to balance the design of the informational content of feedback messages to support student performance in an open-ended, creative design task. This study may also inform the design and implementation of agents (e.g. virtual characters) able to provide user-adaptive feedback for online interactive learning environments.

This study constitutes the first research to examine the informational value of feedback that is chosen rather than received, the latter being the prevalent model of delivering feedback in education.

Addresses the standardization of the measurements and the labels for concepts commonly used in the study of work organizations. As a reference handbook and research tool, seeks to improve measurement in the study of work organizations and to facilitate the teaching of introductory courses in this subject. Focuses solely on work organizations, that is, social systems in which members work for money. Defines measurement and distinguishes four levels: nominal, ordinal, interval and ratio. Selects specific measures on the basis of quality, diversity, simplicity and availability and evaluates each measure for its validity and reliability. Employs a set of 38 concepts ‐ ranging from “absenteeism” to “turnover” as the handbook’s frame of reference. Concludes by reviewing organizational measurement over the past 30 years and recommending future measurement reseach.