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The purpose of this paper is to investigate the driving mechanisms for crack propagation regarding the related microstructures. Cracks in white etching layers have been found at the surface of submerged steel blades subjected to frictional sliding conditions.

In-situ monitoring revealed a fluctuation between mixed lubrication and hydrodynamic lubrication conditions. One lamella including a crack tip was prepared for transmission electron microscopy (TEM) using focused ion beam milling. Transmission electron microscope analysis was performed with the aim to understand the characteristics of the crack propagation, especially considering the influence of the microstructural configuration (grain refinement, carbides, martensite and ferrite grains).

The investigations have shown a grain-refined plastically deformed layer (friction martensite with grain sizes of < 100 nm) which influences the propagation direction of cracks introduced at the frictionally stressed surface. Thereby, the crack propagation is dominantly parallel to the margin of the grain-refined martensitic layer at the surface and the base material. Cracks were split into side cracks what mostly appears at present carbides. In this case, the crack propagation might strike through the carbide or separate it from the matrix due to the mechanical misfit.

For obtaining the results of this paper, a very special preparation of tribologically stressed samples was performed. Accordingly, specific findings of the crack propagation behavior under such conditions were achieved and are documented in the presented work. Moreover, the described crack propagation process is a combination of several mechanisms which occur in very limited region underneath the surface and are investigated by high-resolution TEM.

The term edge cutlery as used in this article refers to spring knives (such as pocket knives which include a flat spring and moveable blades), knives without springs (such as table knives, kitchen, butcher, carving and trade blades, etc.), scissors and cut‐throat razors. The British cutlery trade has a normal turnover of the order of several million pounds per year in these and allied edge products, and approximately half of this is accounted for by exports, so that the trade has to cater for varying climatic and use conditions in a large number of countries all over the world. Corrosive conditions can occur in ordinary use and also during transport and storage, and whilst serious corrosion is rare some examples are sufficiently interesting to warrant examination. Today, corrosion problems in British edge cutlery are almost invariably traceable to extraordinary conditions encountered in transit or in use, and over which the manufacturer often has little or no control. The lessons to be learned from investigation of such cases as do occur nearly always require application by the user, and less frequently, by those responsible for transport and storage.

Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.

The purpose of this paper is to focus on the structural integrity of the rainwater propeller pumps installed in the municipal wastewater treatment plant (WTP).

A numerical analysis is performed to determine the maximum shear stress on the fasten bolts. The rainwater propeller pump is examined in operation at normal conditions and when one blade is progressively blocked.

The failure mechanism of the rainwater pump impeller is determined.

The fibbers and wastes are discharged together with rainwater during storms with these types of pumps to avoid the flood of the WTP. Several catastrophic events have occurred in service due to the fibbers clog the gap between the impeller blades and the pump casing. The clogging process is partially understood so actual technical solutions deal with effects rather the main causes.

The operation time of all seven rainwater pumps installed in Timisoara’s WTP is investigated. Climate changes in Banat region and new waste properties found in the wastewater require appropriate technical solutions. A technical solution is proposed based on these investigations to extend the operation time and to diminish the operation and maintenance costs.

These large pumps are installed in the urban sewage centralised system implemented in the most cities. The access to the sewerage network is a requirement of any community, regardless of the social status.

The fracture surfaces of both fastening bolts of the rainwater pump impellers produced in service are examined. As a result, it has been identified that the catastrophic events are due to the brittle fracture of both fasten bolts between the impeller blades and the pump hub, respectively. The catastrophic events of the rainwater propeller pumps are directly correlated to the clog level of the impeller. The numerical simulation is performed to determine the maximum shear stress on the fasten bolts. The case with pump operating at normal conditions is performed identifying its vulnerabilities to clog conditions. Next, one impeller blade is progressively blocked considering three time stop scenarios associated with different clog levels. Conclusively, the operating time of the rainwater pump up to the catastrophic failure is correlated to the clog level of the impeller.

ALTITUDE supercharging of aeroplane engines by means of turbo‐blowers driven by exhaust‐gas turbines differs from ordinary charging of internal combustion engines because the process is much more accentuated. Whilst the output of stationary engines can be increased by 50 per cent, that of rail‐car engines by 80 per cent, by supercharging, an aeroplane engine, to give its full output at 12,000 m. altitude, has to be supercharged so as to give four times its output without supercharging. Thus altitude supercharging offers certain peculiarities.

This paper aims to synthesize anticorrosion pigments containing tungsten for paints intended for corrosion protection of metals.

The anticorrosion pigments were prepared by high-temperature, solid-state synthesis from the respective oxides, carbonates and calcium metasilicate. Stoichiometric tungstates and core-shell tungstates with a nonisometric particle shape containing Ca, Sr, Zn, Mg and Fe were synthesized. The pigments were examined by X-ray diffraction analysis and by scanning electron microscopy. Paints based on an epoxy resin and containing the substances at a pigment volume concentration (PVC) = 10 volume per cent were prepared. The paints were subjected to physico-mechanical tests and to tests in corrosion atmospheres. The corrosion test results were compared to those of the paint with a commercial pigment, which is used in many industrial applications.

The tungstate structure of each pigment was elucidated. The core-shell tungstates exhibit a nonisometric particle shape. The pigments prepared were found to impart a very good anticorrosion efficiency to the paints. A high efficiency was demonstrated for the stoichiometric tungstates containing Fe and Zn and for core-shell tungstates containing Mg and Zn.

The pigments can be used with advantage for the formulation of paints intended for corrosion protection of metals. The pigments also improve the paints’ physical properties.

The use of the pigments in anticorrosion paints for the protection of metals is new. The benefits include the use and the procedure of synthesis of anticorrosion pigments which are free from heavy metals and are acceptable from the environmental protection point of view. Moreover, the core-shell tungstates, whose high efficiency is comparable to that of the stoichiometric tungstates, have lower tungsten content.

SINCE its inception, but a few years ago, the Institute of the Aeronautical Sciences has grown remarkably in the size and distinction of its membership, and the technical value of the papers appearing in its journal is now thoroughly well established. Thanks in a large measure to the organizing ability of its Secretary, Lester D. Gardner, the annual meeting was a great success. For the first time in its brief history simultaneous sessions were held, a method which works out quite well in the specialized atmosphere of modern aeronautics. The great difficulty with the annual meetings of American societies is that they are so huge as to render intellectual assimilation problematical. But the geographic conditions of the United States make it impossible for members from different parts of the country to attend frequent meetings such as those of the Royal Aeronautical Society.

Conventional investment casting of turbine blades is a time consuming and expensive process due to the complications in wax injection steps and the complex shape of airfoil surfaces. By using rapid investment casting, a substantial improvement in the gas turbine blade manufacturing process can be expected. However, this process needs to be able to compete with conventional investment casting from a dimensional accuracy view of point. The purpose of this paper is to investigate the manufacture of gas turbine blades via two indirect rapid tooling (RT) technologies, namely epoxy (EP) resin tooling and silicon rubber molding.

The second stage blade of a Ruston TA 1750 gas turbine (rated at 1.3 MW) was digitized by a coordinate measuring machine. The aluminum‐filled EP resin and silicon rubber molds were fabricated using StereoLithography master models. Several wax patterns were made by injection in the EP resin and silicone rubber molds. These wax patterns were utilized for ceramic shell fabrication and blade casting.

Dimensional inspection of cast blades showed that silicone rubber molding was not a suitable approach for production of blade wax patterns. The maximum deviation for the final cast blade made using the silicone rubber mold was +0.402 mm. The maximum deviation for the final cast blade made using the EP resin mold was lower at −0.282 mm. This showed that EP resin tooling could enable new cost‐effective solutions for small batch production of gas turbine blades.

The research results presented will give efficient industrial approach and scientific insight of the gas turbine blade manufacturing by use of rapid technologies.

There are some general research works related to utilization of rapid technologies for manufacturing of gas turbine blade. However, this paper presents a unique procedure of integrated reverse engineering and RT technologies for rapid investment casting of gas turbine blade through presenting comprehensive comparison between two techniques from dimensional accuracy view of point.

NOT perhaps the most vintage of Farnboroughs from the point of view of new aircraft and new technology, but undoubtedly one of the most successful in relation to the business done. Some fifteen major orders worth over £32½ million were announced, bringing the total order book for the industry this year to more than £782 million already. This exceeds by a handsome margin the new business won by the industry in any nine‐month period in the past, and it is expected that by the end of the year orders worth well over £800 million will have been received. Highlights of the new British hardware on show were the Hawker Siddeley Nimrod and production Harriers on the military side; the B.A.C. One‐Eleven 500, the Handley Page Jetstream, the Garrett‐engined Short Skyvan, and the Beagle Pups showed the resurgence of the industry's civil interests. The number of foreign aircraft that appeared, sponsored in the main by Rolls‐Royce, bore witness to the strength of Britain's aero engine and aircraft equipment industry, and further evidence of this was found in the exhibition proper with many examples of major items of equipment having been adopted for overseas markets. The overall impression at Farnborough was a new‐found confidence in the future of the industry exemplified by a more aggressive and effective export sales policy that has already proved our ability to deliver the goods. It is not possible to cover all the exhibits shown at Farnborough, but the report following describes many of the interesting items.

The application of cathodic protection to buried, submerged or immersed metals has become of increasing importance during the last three decades to civil, structural, mechanical, marine and chemical engineers. Although, at the moment, it has only a limited application for the protection of chemical plant, the method may become more important in this field in the future. The principles of cathodic protection, its applications, advantages and limitations and some of its present uses in protecting chemical plant are considered in the following article.