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The purpose of this paper is to communicate and share experiences with other dam designers, operators and maintenance officers arising from the rehabilitation of the Osborne Dam outlets, pursuant to informing future dam outlet designs and rehabilitation of similar dam outlets.

This paper documents and utilizes actual events that occurred before and during the rehabilitation of the outlets. Some solutions applied were unique, with resultant innovative engineering designs being decided on site. Realizing that a descriptive research format would best serve the sharing of experiences of the outlets’ rehabilitation, the case study approach was selected. Before commencement of the rehabilitation works, the different operational problems that had been identified, photographed and documented by the dam’s operating staff were verified by the dam owner’s engineers, technicians and consultants. Visual and photographic verification was done using divers for areas under water. Literature review was conducted so as to learn from solutions employed elsewhere. A physical model of the solution considered the best way to keep the intake tower dry was made and tested.

The outlets’ rehabilitation works, taking 12 months to complete at a total cost of US$5 million, involved installation of new service gates, replacement of the sleeve valves, refurbishment of the butterfly valves and provision of dewatering pumps.

This paper offers unique experiences and lessons for dam designers and other dam operation and maintenance officers while contributing to the body of knowledge of outlet works rehabilitation.

The purpose of this article is to inform the reader of the various options available today in the management of power and communication systems within a library. These options are measured against several factors: the library’s program goals, its budget, and its structure. As library architects and interior designers, the design of the building must meet the user’s needs and the owner’s goals and be flexible to change as these needs and goals change. The facility’s ability to support technology and provide for adaptation to future changes is key to its success. This article describes six methods of managing and accessing power and communication in both new and renovated facilities. It describes the advantages and disadvantages of each system, and provides examples of their practical applications. The solutions to managing wiring for power and communication within the furniture systems is also discussed relative to how the connections interface with the building and the users. On reading this article, librarians and owners will have a better understanding of the options available and how their decisions regarding these options impacts the future adaptability of the facility.

In a wing construction for an aeroplane, the combination of a sheet metal surface, a channel‐shaped stringer member having outwardly extending flanges secured to said sheet metal surface to co‐operate in supporting the same, said channel member being cut away at portions of said flanges to form transverse passages adjacent to the sheet metal surface, a web member extending transversely of and substantially perpendicular to said stringer member provided with a strengthening channel of slightly greater size than the channel of the stringer member, the top surface of the channel of the web member at the end of the web member being cut away to fit about the channel of the stringer member, and a holding member having a slot to accommodate the channel of the stringer member, said holding member having a part secured to said web member and a part at substantially right angles to the first part secured to the sheet metal surface.

Screw propellers arranged in tandem and oppositely rotated are adapted to be varied in pitch by a double sun and planet control of one propeller by an operating gear passing through the hollow propeller shaft whilst the first propeller through a second set of double sun and planet gears adjusts the second propeller. An electric motor 29, or a hydraulic motor, is employed to actuate the shaft 25 carrying at its lower end a bevel wheel 24 which meshes with a bevel wheel 23 on a tubular shaft 20 which passes through the hollow hub and at its forward end carries a spur‐wheel 30. Within this shaft 20 is a second shaft 19 which is fixed at its inner end to the engine casing 21, and at its other end carries a gear wheel 22. These wheels 22 and 30 constitute twin sun wheels and between them is a spider 31 carrying planet wheels 32, 33 of which the wheels 32 which mesh with the fixed sun wheel 22 also coact with an internally toothed ring 34 mounted to rotate as one with the front propeller 11, while the planet wheels 33 which mesh with the adjustable sun wheel 30 also coact with an internally toothed ring 35 which is freely mounted on the propeller and which by reason of the outer ring of teeth 36 and the pinions 37 provide for the actuation of the shaft 38 whereby the pitch of the blades is adjusted. The shaft 38 is continued to carry a pinion 41 which meshes with the second pinion 42 freely mounted on the hub and continued to drive a similar double sun and planet wheel layout which in turn actuates the adjusting shaft 52 of the second propeller 12. The arrangement for actuating the pitch adjusting gear is also utilized to actuate a pitch indicator and for this purpose the spindle 25 carries an extension which through suitable gearing is conveyed to the indicator. Specification 398,993 is referred to.

In an aircraft, a revoluble thrust‐producing system including a hub, a generally radially disposed airfoil blade pivotally secured to and carried by said hub by a corresponding single pitch‐varying blade‐root pivot whose axial line of pivotation is fixed in relation to the longitudinal axis of the blade‐root and passes outwardly from said hub on the back or pressure side of the airfoil blade in a generally radial direction and diverges from the airfoil blade as it goes outwardly from said hub, and passes through the stable region of the resultant air‐load vectors of the airfoil.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Technical Reports and Translations of the United States National Aeronautics and Space Administration and publications of other similar Research Bodies as issued.

A gas turbine power plant comprising a compressor assembly consisting of a compressor rotor and an enclosing stationary structure, a turbine assembly consisting of a turbine rotor coaxial with the compressor rotor and an enclosing stationary structure, a shaft carrying said rotors, a combustion system accommodated between the compressor and turbine assemblies, said combustion system including an annular air‐casing formed by an inner and outer tubular member mounted coaxially with the shaft and defining between them a flow path from said compressor to said turbine extending generally in an axial direction, and a plurality of flame tubes mounted within and annularly distributed around said air‐casing, said outer tubular member being a unitary structure, the internal diameter of which over at least part of its length adjacent one end, is greater than the external diameter of the stationary structure adjoining said end of the tubular member, the external diameter of said stationary structure being less than the internal diameter of said tubular member from a point adjacent said end of said tubular member to a point located a substantial distance in a direction axially away from said tubular member, whereby said tubular member can be withdrawn over said stationary structure to expose the flame tubes.

In combination with an aeroplane having a wing for sustaining purposes, an aileron pivotally supported adjacent the wing and adapted to float freely, and a hinged tab associated with the aileron and adapted in response to tilting relatively to the aileron during flight of the aeroplane to control the angular position of said aileron with respect to the air stream, a system for controlling the tab comprising a cam mounted to rotate about the pivot axis of the aileron, pilot actuated means for turning the cam relatively to the wing, a cam follower in operative engagement with the cam, and an operating connexion extending between the cam follower and the tab and operative to tilt the tab relatively to the aileron in response either to turning of the cam relatively to the wing or to relative turning of the cam and aileron, said cam being so designed that when it is in a neutral stationary position with respect to the wing and said wing is caused in connexion with flight to change its angle of attack from zero to stall it effects tilting of the tab into a position wherein it causes the aileron to assume substantially the same angle of attack as the wing and being also so designed that when it is in its said neutral stationary position with respect to the wing and such wing is caused to increase its angle of attack above the stall angle it positively maintains the tab in a fixed tilted position with respect to the aileron.

These abstracts of patents granted in the United States are taken, by permission of the Department of Commerce, from the ‘Official Gazette of the United States Patent Office’. Printed copies of the full specification can be obtained, price 10 cents each, from the Commissioner of Patents, Washington, D.C., U.S.A. They are usually available for inspection at The British Patent Office, Southampton Buildings, Chancery Lane, London, W.C.2.

A recent report, commissioned by Vigers Chartered Surveyors and carried out by the Building Performance Unit at Liverpool Polytechnic, has collected extensive evidence of defects in raised floors. One of its central themes is to provide guidelines for facilities managers wishing to obtain value for money from their raised floor installations. This article provides advice to managers who wish to extend the life cycle of raised floors in their care and in doing so reduce the scale of defects in use.