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Our contributor, Robert W. Tong, is a service engineer in Johannesburg and maintains air compressors, and other machines, within several hundred miles of this city. These are some notes in the form of hints and tips which we have received from him concerning the practical side of his job and once again, as in previous contributions, he makes a few complaints which he suggests could be remedied by British manufacturers if they gave a little more consideration to the problems of engine maintenance by their customers in Africa and similar countries where skilled staff is often non‐existent.

Mr. Tong once again contributes an article on conditions he meets with in his travels overseas. He stales that he has come across many glaring examples of waste caused by neglect of simple precautions and lack of enthusiasm by personnel concerned, and gives details of procedure for preventing such waste.

The article by Mr. Brian J. Vaughan in the January issue of Scientific Lubrication, dealing with the chemical and theoretical qualities necessary in refrigerator oils, was of great interest to users of refrigerating machines, and these notes are submitted as a practical supplement to Mr. Vaughan's paper.

In recent articles it has been stressed several times that it is of the utmost importance that machinery intended for use in a great many places overseas must be of the simplest possible design, and this point cannot be made too often. Once again the particular area in mind is South Africa, and the particular plant referred to is the Oil engine, for here, except for the large engines which go to proper stations, these engines have to run with little or no skilled supervision.

Earlier notes on this subject have been published in our December 1950 issue, and the writer here adds a few more observations from his day‐to‐day experience in South Africa, for he feels that the lubrication problems of these areas are definitely not receiving the care and attention from designers and suppliers in England that they should.

The following article is substantially the same as a lecture given to The Institute of Petroleum at Leeds on 9th April, 1959, and is reproduced here by their kind permission.

Aim of the present monograph is the economic analysis of the role of MNEs regarding globalisation and digital economy and in parallel there is a reference and examination of some legal aspects concerning MNEs, cyberspace and e‐commerce as the means of expression of the digital economy. The whole effort of the author is focused on the examination of various aspects of MNEs and their impact upon globalisation and vice versa and how and if we are moving towards a global digital economy.

The librarian and researcher have to be able to uncover specific articles in their areas of interest. This Bibliography is designed to help. Volume IV, like Volume III, contains features to help the reader to retrieve relevant literature from MCB University Press' considerable output. Each entry within has been indexed according to author(s) and the Fifth Edition of the SCIMP/SCAMP Thesaurus. The latter thus provides a full subject index to facilitate rapid retrieval. Each article or book is assigned its own unique number and this is used in both the subject and author index. This Volume indexes 29 journals indicating the depth, coverage and expansion of MCB's portfolio.

In order to improve the engine reliability and efficiency, an effective way is to reform the turbine blade tip conformation. The paper aims to discuss this issue.

The present research provides several novel tip-shaping structures, which are considered to control the blade tip loss. Four different tip geometries have been studied: flat tip, squealer tip, flat tip with streamwise ribs and squealer tip with streamwise ribs. The tip heat transfer and leakage flow are both analyzed in detail, for example the tip heat transfer coefficient, tip flow and local pressure distributions.

The results show that the squealer seal and streamwise rib can reduce the tip heat transfer and leakage loss, especially for the squealer tip with streamwise ribs. The tip and near-tip flow patterns at the different locations of axial chord reflect that both the squealer seal and streamwise rib structure can control the tip leakage flow loss. In addition, the analysis of the aerodynamic parameters (the static pressure and turbine efficiency) also indicates that the squealer tip with streamwise ribs obtains the highest adiabatic efficiency with an increase of 2.34 percent, compared with that of the flat tip case.

The analysis of aerothermal and dynamic performance can provide a reference for the blade tip design and treatment.