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THE problem involved in obtaining satisfactory surface contours for assemblies such as are required in modern aircraft development demands for its successful solution the co‐ordinated, concentrated efforts of all those concerned with both the design and manufacturing processes. Even the casual observer can see that, if optimum performance is to be realized, the external skin or covering, whether made of thin sheet stock or precision machined from heavier plate stock, must be continuously smooth.

A FREQUENTLY recurring problem, more particularly in the sphere of electrical engineering practice, is the determination of the equivalent rating of a machine or piece of apparatus under conditions of intermittent loading. By equivalent rating is to be understood the value of the continuous load, whether expressed in terms of current or power, which will produce the same final temperature rise as is actually produced by the given intermittent load.

AXIAL flow fans were originally developed from aircraft airscrews and therefore can be claimed as children of aeronautical science. Their use has been confined in aeronautics to wind tunnels and radial engine cooling until the advent of ‘pressurized’ cabins. In this case ventilation requirements have caused an axial flow fan to be used. These fans have been gradually developed in the ventilation industry and they are replacing centrifugal fans where these would have been used previously. Price and noise level have not been in the axial flow fans' favour in this fight but they have advantages of higher efficiency, ease of installation and non‐overloading power characteristic. Latest developments in aerodynamic design and production technique suggest that the disadvantages are being overcome. This note is intended to furnish a general introduction to the design features of axial flow fans for aircraft ventilation.

This American textbook, originally reviewed in AIRCRAFT ENGINEERING, Vol. xvi, June, 1944, p. 170, has now been made available in Great. Britain, so attention may again be called to it as it provides a practical means of applying analytical geometry to aircraft lofting. The author is head of Engineering Loft' Mathematics at North American Aviation, Inc. He thus occupies a position which has no counterpart in the average British firm, and the book is interesting as an insight into modern American methods.

THE considerable difficulties encountered in designing a test rig which would allow of unbroken fuel supply from tanks whose attitude was being changed continuously was successfully overcome.

Introduction How old is concrete? 150 years, 2,000 years or 9,000 years? Since the invention of Portland cement by Aspdin in the early 19th century, concrete has become the most widely used construction material in the world. Yet, concrete durability can pose severe constraints on the concrete engineer and designer. In the search for materials which are more cost‐effective or more efficient, cement replacement materials such as natural pozzolans, calcined clays, shale and soils, slags, rice husk ash or pulverised fuel ash are attracting much interest. Are these cheap replacement materials not compromising on quality and long‐term durability? A first optimistic answer is given in this paper which will be especially useful for practising civil and structural engineers, materials technologists, engineers and designers.

The purpose of this paper is to identify factors affecting performance of heritage conservation projects in terms of project management parameters of time, cost, and quality.

An exploratory study was conducted in India, wherein 41 conservation professionals were interviewed. The method adopted for the study was unstructured interviews, wherein the respondents were asked open-ended questions about the issues faced in such projects and factors affecting project performance.

The interview recordings and notes, made during the exploratory study, have been manually coded to identify the most frequently mentioned problems, group them into categories, and assess their relative importance.

This paper has presented a broad overview of the challenges faced by heritage conservation projects in general. Further research is necessary to analyse if the challenges depend on factors like type of heritage, project delivery model, and stakeholders involved, and to develop mitigation strategies for these challenges.

The findings from this study can be used by practitioners to improve performance of heritage conservation projects in terms of time, cost, and quality.

The findings of the exploratory study help to better understand the reasons of poor performance of heritage conservation projects in terms of time, cost, and quality. The paper has identified major challenges of the sector, and assessed their relative importance, which can help in developing project management strategy for future projects.

The daily loaf or cake of bread is undoubtedly Man's first and oldest form of prepared food. Except in the the cereal used to make it, it differs little the world all over, but changes are taking place in this staple food, in its preparation and distribution. In recent legal proceedings, a charge of selling a loaf not of the nature, etc., in that it contained rodent contamination, was brought against partners in what was described as the last surviving family baker's business in a relatively large and populous suburban area of London. “Take‐over bids” are the order of the day and in modern business, which includes the baking of bread, the accent is on combination and concentration. The Magistrates must have had a wistful regard for the things that are passing for they fined the “little man” about half the amount they subsequently fined a larger undertaking for a similar type of offence.

The report of the Departmental Committee on the Irish butter industry to the Department of Agriculture and Technical Instruction for Ireland was issued on March 23 as a parliamentary paper. Mr. J. R. CAMPBELL was chairman of the Committee, and the other members were Mr. T. CARROLL, Mr. E. G. HAYGARTH‐BROWN, Lord CARRICK, and Mr. A. POOLE WILSON, with Mr. D. J. MCGRATH as secretary. The Committee were appointed:—

LONG before man learnt to make fire by the friction of wood, he experienced the burden of friction in dragging home his kill. Perhaps it is not too fanciful to suppose that the torn sides of his beast gave the first solid lubricant. Blood and mutton fat were seriously recommended as lubricants for church bell trunnions as recently as the 17th century. Indoed we still reckon fatty acids the best of all boundary lubricants. The range of man's activities has increased enormously in the present century, and particularly in the last few decades. Men have circled the earth in space; a space ship is on its way to examine another planet; terrestrial man is boring to the bottom of the earth's crust; others have descended to the depths of the ocean, and oven established a home on the floor of the Mediterranean, Speeds have increased by factors of thousands, temperatures range from near absolute zero to thousands of degrees; and a new environment of high‐intensity nuclear radiation has been created. Still, objects must move over and along each other in these exotic conditions; and to a large extent solid lubricants can provide the answer to the frictional problems.