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A review is made of methods for calculating parameters characterizing crack tip behaviour in non‐linear materials. Convenient methods of calculating J‐integral type quantities are reviewed, classified broadly into two groups, as domain integrals and virtual crack extension techniques. In addition to considerations of how such quantities may be calculated by finite elements, assessment methods of conducting the actual incremental analyses are described.

Theoretical investigations have been performed on slowly propagating cracks in T‐junctions and cross bars using computer procedures developed to analyse the amount and direction of crack growth using automatic mesh modification and the finite element stress analysis program, BERSAFE. The procedures may be used in a linear or non‐linear material. The crack growth for the linear elastic case is calculated to be in the direction of the maximum energy release rate. For the non‐linear case, the direction is taken to be that of Jwi. These procedures have been applied to fatigue crack growth calculations in this paper.

The purpose of this paper is to present special nine‐node quadrilateral elements to discretize the un‐cracked boundary and the inclined surface crack in a transversely isotropic cuboid under a uniform vertical traction along its top and bottom surfaces by a three‐dimensional (3D) boundary element method (BEM) formulation. The mixed‐mode stress intensity factors (SIFs), K_I, K_II and K_III, are calculated.

A 3D dual‐BEM or single‐domain BEM is employed to solve the fracture problems in a linear anisotropic elastic cuboid. The transversely isotropic plane has an arbitrary orientation, and the crack surface is along an inclined plane. The mixed 3D SIFs are evaluated by using the asymptotical relation between the SIFs and the relative crack opening displacements.

Numerical results show clearly the influence of the material and crack orientations on the mixed‐mode SIFs. For comparison, the mode‐I SIF when a horizontal rectangular crack is embedded entirely within the cuboid is calculated also. It is observed that the SIF values along the crack front are larger when the crack is closer to the surface of the cuboid than those when the crack is far away from the surface.

The FORTRAN program developed is limited to regular surface cracks which can be discretized by the quadrilateral shape function; it is not very efficient and suitable for irregular crack shapes.

The evaluation of the 3D mixed‐mode SIFs in the transversely isotropic material may have direct practical applications. The SIFs have been used in engineering design to obtain the safety factor of the elastic structures.

This is the first time that the special nine‐node quadrilateral shape function has been applied to the boundary containing the crack mouth. The numerical method developed can be applied to the SIF calculation in a finite transversely isotropic cuboid within an inclined surface crack. The computational approach and the results of SIFs are of great value for the modeling and design of anisotropic elastic structures.

Additive manufacturing (AM) of thermoplastic polymers for powder bed fusion processes typically requires each layer to be fused before the next can be deposited. The purpose of this paper is to present a volumetric AM method in the form of deeply penetrating radio frequency (RF) radiation to improve the speed of the process and the mechanical properties of the polymer parts.

The focus of this study was to demonstrate the volumetric fusion of composite mixtures containing polyamide (nylon) 12 and graphite powders using RF radiation as the sole energy source to establish the feasibility of a volumetric AM process for thermoplastic polymers. Impedance spectroscopy was used to measure the dielectric properties of the mixtures as a function of increasing graphite content and identify the percolation limit. The mixtures were then tested in a parallel plate electrode chamber connected to an RF generator to measure the heating effectiveness of different graphite concentrations. During the experiments, the surface temperature of the doped mixtures was monitored.

Nylon 12 mixtures containing between 10% and 60% graphite by weight were created, and the loss tangent reached a maximum of 35%. Selective RF heating was shown through the formation of fused composite parts within the powder beds.

The feasibility of a novel volumetric AM process for thermoplastic polymers was demonstrated in this study, in which RF radiation was used to achieve fusion in graphite-doped nylon powders.

Investigates the possible social causes of unemployment; focuses on how competition among employers can increase and perpetuate already high levels of unemployment. Starts from the premise that, despite divergent attitudes, most industrialized nations make some collective provision for the unemployed, with firms ultimately bearing the costs. Describes how, although a firm may reduce its labour force to save money, it is ultimately, albeit collectively, paying the costs of unemployment via taxes to the State ‐ the main effect is to redistribute the costs to other organizations; depicts a resulting downward spiral in the economy. Looks at the relationships between increased productivity and the costs to society. Concludes that competitive unemployment is a reality and suggests possible solutions.

Since the incident at Westminster Abbey last Christmas, Scottish nationalistic pride, or self‐consciousness, has been widely advertised. In many respects the existence of that attitude of mind does no harm to His Majesty's subjects in England and Wales. But now a genuine grievance against the Scots—which has existed for some years, though few people have been aware of it—has at last received publicity. It arises from the fact that several of the provisions of the Food and Drugs Act, 1938, do not apply to Scotland—doubtless because the Scots had represented that they would be unacceptable. Among those provisions was Section 101, which incorporated with the Act the whole body of regulations, including those relating to preservatives in food, which had been made in pursuance of the Public Health Acts. Similar Regulations, it is true, do apply in Scotland, but a breach of them is an offence, not under the Act of 1938, but under the Food and Drugs (Adulteration) Act of 1928, which is wholly repealed so far as England and Wales are concerned. Recently the Corporation of Blackburn persuaded the local justices to convict a company, registered and trading in Scotland, of an offence against the Act of 1938 on the ground that boric acid had been found in biscuits manufactured by the company in Scotland and sold to a Blackburn retailer. The Scottish company was not prosecuted by the Blackburn Corporation but was brought in under s. 83(1) by a previous defendant. Counsel for the defence took the points that a Scottish firm cannot be haled before an English Court in respect of an alleged offence which, if it was committed at all (which was disputed), was committed in Scotland, where the Food and Drugs Act, 1938, is not in force. Incidentally it may be observed that the presence of boric acid in the biscuits was due to the use of margarine containing not more than the permitted percentage of the preservative. The magistrates chose to convict the Scottish company as the person to whose act or default a contravention of the provisions of the English Act was due. On appeal to the Divisional Court, the conviction has now been annulled, primarily on the ground that the Blackburn bench had no jurisdiction to hear a summons against the Scottish company. Section 83, like many other sections of the Act of 1938, does not apply to Scotland, except with respect to prosecutions under the Orders made by the Minister of Food under. Defence Regulations—for example, the various Food Standards Orders and the Labelling of Food Order. (See particularly Regulation 7(3) of the Defence (Sale of Food) Regulations, 1943, and Article 15(c) of the Labelling of Food Order, 1946.) Still, if Scotsmen insist on not being subject to the English food laws as a whole, it would be unreasonable for them to expect that those who sell food in England and Wales should be willing to be deprived of the safeguards which the Act of 1938 confers on innocent dealers who have been let down by their suppliers. The Scots may find that English retailers of food will boycott Scottish products. Provided always that nothing in this Article shall be deemed to apply to the sale or purchase for human consumption in England or Wales of the article of food distilled in Scotland and commonly known as Scotch or Scottish Whisky, if the food is so described in an invoice or on a label bearing the name and address of the distiller. The point of which proviso is to show that I am not such a nitwit as to think that anything that I write will deter or discourage any Englishman from acquiring a bottle of Scotch if he knows where and how he can get it.

June 22,1972 Damages — Remoteness — Negligence — Economic loss — Contractors damaging cable supplying electricity to factory — Physical damage to metal in factory's furnace as result of power cut — Loss of profit from “melt” and from further melts which would have taken place if no power cut — Whether economic loss recoverable — Whether economic loss attaching to physical loss recoverable — Doctrine of parasitic damages.

The purpose of this paper is to investigate the electrical conductivity and corrosion protection properties of a conductive coating composed of epoxy resin and carbon black in a sodium chloride (NaCl) solution.

The conductive coating was prepared by combining epoxy resin, hardener, and carbon black. The electrical conductivity of the paint was studied with a DC current‐voltage meter and field emission scanning electron microscopy. The corrosion protection properties of the paint were characterized by open circuit potential measurements and electrochemical impedance spectroscopy.

The highest conductivity observed was 4.23×10⁻⁴ Scm⁻¹ for the coating containing 20 wt% carbon black. The coating protected mild steel in a 3.0 percent NaCl solution for up to five days.

The results shown in this paper provide an insight into conductive paint and corrosion protection for future industrial applications and development.

Armstrong, Whitworth Aircraft, Ltd., Coventry.—Aircraft, Reconditioning of: Supermarine Aviation Works (Vickers), Ltd., Woolston. Aircraft, Spares: Blackburn Aeroplane & Motor Co., Ltd., Brough; Westland Aircraft Works, Yeovil.—Bitumen: Asiatic Petroleum Co., Ltd., London, E.C.—Blocks, Terminal: Oliver Pell Control, Ltd., London, S.E.—Brushes: C. H. Leng & Sons, Birmingham.—Camera Spares: Thornton Pickard Manufacturing Co., Ltd., Altrincham.—Canvas Duck: Jas. Stott, Ltd., Oldham.—Coats, Great: L. Silberston & Sons, London, E.—Cylinders: Walter Kidde Co., Ltd., Hanwell.—Dopes and Identification Colours: Nobel Chemical Finishes, Ltd., Slough.—Engines, Aero, Reconditioning and Spares: Bristol Aeroplane Co., Ltd., Filton.—Engines, Aero, Spares, Repair of: D. Napier & Son, Ltd., London, W.—Engines, Aero, Spares: Rolls‐Royce, Ltd., Derby.—Glycerine: D. Thorn & Co., Ltd., Pendleton.—Landplane: De Havilland Aircraft Co., Ltd., Edgware.—Lay‐out of Moorings and Mark Buoys: Thos. Round & Sons, Scarborough.—Limousines, Humber, Pullman: Rootes, Ltd., Coventry.—Locomotive, Diesel: F. C. Hibbard & Co., Ltd., London, N.W.—Magnetos: British Thomson‐Houston Co., Ltd., Coventry; Rotax, Ltd., London, N.W.—Mahogany: M. A. Morris, London, N.—Nippers: Wynn Timmins & Co., Ltd., Birmingham.—Pantaloons: L. Silberston & Sons, London, E.—Plugs and Sockets: Vickers (Aviation), Ltd., Weybridge.—Pumps, Fuelling: Zwicky, Ltd., Slough.—Thermometers, Radiator: Negretti & Zambra, London, E.C —Transmitters: Standard Telephones and Cables, Ltd., London, N.W.—Trays for Racks: Hobbies, Ltd., Dereham.—Valves W/T: Edison Swan Electric Co.,Ltd., London, W.C.—Waistcoats, Life Saving: Robinson & Cleaver, Ltd., London, W.

It has often been said that a great part of the strength of Aslib lies in the fact that it brings together those whose experience has been gained in many widely differing fields but who have a common interest in the means by which information may be collected and disseminated to the greatest advantage. Lists of its members have, therefore, a more than ordinary value since they present, in miniature, a cross‐section of institutions and individuals who share this special interest.