ICE - Institution of Civil Engineers - Virtual Library

52 The Author. DISCUSSION ON THE MECHANICAL [Minutes of soft irons and mild steels did mend themselves and recover their elasticity by mere lapse of time'. A comparatively slight change of temperaturein a metal, due, for instance, t o boiling inwater, accelerated the process of mending2. In the Paper by the Author referred to, examples were given of two test-pieces; one of them recovered its elasticity a t ordinary temperatures ina night, and the other, when tested after n year's interval, was found to give exactly the same hysteresis " loop as when tested 12 months previously...

26 DISCUSSION ON THE DESIGN OF SEWAGE-PURIFICATION WORKS. Discussion. TheAuthor, inintroducing his Paper, showed anumber of lantern slides. He observed that one criticism which had been made of the Paper was that he had devoted twice as much space to the percolating filter as to the activated-sludge process. The only reply he could give was that he had known the percolating filter for 40 years, and the activated-sludge process for only half that time. Mr. R. G. Hetherington observed that the Author had referred to progress in the design of sewage-purification works having been made empirically, especially in connexion with the percolating filter...

Discussion. Mr. Watson introduced his Paper with the aid of a series of lanternslides. The picture, as he saw it, was that of two groups of engineers, one concerned with producing efficient aeroplanes and the other concerned with the provision of efficient runways, and a compromise would have to be worked out between them. The third and probably the most 494 DISCUSSION ON THE DESIGN OF AIRCRAFT AND AIRFIELDS. important party was the user, who would have to strike a balance between having inefficient aeroplanes in order to save money on runways and spending a great deal of money on runways in order to get the most efficient aircraft...

CORRESPONDENCE ON PAPERSPUBLISHED APRIL 1937 JOURNAL Paper No. 51201. IN West Middlesex Main Drainage." By DAVIDMOWATWATSON, BSc., M. Inst. C.E. Correspondence. Mr. J . S. ALBORD asked if the Author would supplement his des- Mr. Alford. cription by adding to the illustrationsalongitudinal section or profile diagram of one of the siphons, preferably the Brcnt siphon, as the Minutes of Proceedings contained but little information on the subject of the conveyance in inverted siphons of liquid containing solids in suspension. Mr...

464 CORRESPONDENCE ON HAMMER-BLOW IN LOCOMOTIVES. CORRESPONDENCE ON PAPERSPUBLISHED IN JANUARY 1942 JOURNAL Paper No. 5243. (1 ) L ` Hammer-Blow in Locomotives : can it notbeabolished altogether ? " t BySirHAROLDNUGENTCOLAM, B.A., M. Inst. C.E., and Major JOHN DOUGLAS WATSON, B.Sc. (Eng.), Assoc. M. Inst. C.E. R.E., (2) " Balancing of Locomotive Reciprocating Parts." By ERNEST STEWART Cox, A...

58 FISHER, GOODE, AND DOCKER O N SOME PROBLEMS IN THE 3. A. L. Morse, " The Correlation of Aircraft Take-off and Landing Characteristics with Airport Size ". C.A.A., U.S. Dept. of Commerce, April 1944. 4. Portland Cement Association, `` Design Data and Recommended .Details for Concrete Airport Pavements ". Chicago,1942. 5. H. M. Westergaard, "Stresses in Concrete Pavements computed by Theoretical Analysis ". Proc. Highway Research Board, vol...

32 DISCUSSION ON PRESENT AND FUTURE DEVELOPMENTS linings are at present the rule rather than the exception on plant of this type. ( d ) On hydraulically actuated tipping bodies, this action should be speeded up by the of equipment withincreased flow a t higher pressures. use Road Transport forEarth-moving Plant. Experience has shown the following features to be fundamental for future types of transport. Standardized well-type trailers of 10- 20- and 40-ton capacitywith adequate platform length,large wheels, hydraulically actuated folding front platform-ramp, and detachable front steering bogie with standard turntable type coupling...

30 DISCUSSION ON THE EFFECTS OF JET Discussion The Authors introduced the Paper with aid of a film illustrating the effects of a Vampire jet, operating at different outputs, on various kinds of surfacing. Mr K. C. Mann said that only co-operation between aircraft designers and airfield designers would prevent the problem which had arisen through the adoption by the aircraft industry of jet engines from becoming almost insoluble. If the aircraft designers were to accentuate still further the trend that was shown in Fig. 3 (a) (Attacker) by designing aircraft with even greater downward inclination of the jet, he thought that nothing short of some expensive refractory material would be necessary on the runways ; and in point of fact the jet people would put themselves out of business, because it would be too expensive to put aircraft on the ground ! The film had shown that the Vampire's jet had devastating effects...

SYMPOSIUM OF NOTES ON ROAD PROBLEMS. 21 was revolving. Yh time t,aken for mixing by this nwt,hod W:LS 3-4 !e minutes. As an alternativemethod for mixing, experiments were carried out using compressed air. The apparatus employed (Fig. 10) consisted of a Broomwade air-compressor with a 30-foot length of pipe connected to a 75-gallon galvanized-iron tank supported on a specially designed movable platform constructed of tubular steel members. The tank had Q-inch diameter holes cut 1 inch from its base and was connected t o a grid, placed inside the tank, made up of $-inch and &inch water-pipes whichwere drilled with holes...

110 DISCUSSION ON PORTLAND CEMENT AND [Minutes of Discussion. The President. The PRESIDENT a vote of thanks to the Author for his very moved interestingdescription of the modernmethods of manufacturing cement. The Author. The AUTHOR exhibited a number of lantern-slides illustrating the difference between the methodspractised inthe earlydays of theindustryand those now employed. The first slide went back to 1752 and showed Gravesend, now the chief seat of the cement-industry of Great Britain. nucleus The of the cernentindustry existed a t t h a t time inthe form of lime-kilns in the vicinity of Northfleet and Swanscombe; and the site of the high chalk cliffs shown in the slidewas nowoccupied by some of the largest cement-works in the kingdom...