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Specimen thickness has great influences on the creep behavior of single crystal Ni-based superalloys when it is less than 3.0 mm, which is known as thickness debit effect. Experiments have detected that oxidation can influence the microstructure of the Ni-based superalloys. Here, a model is proposed to bring in both the oxidation effect and void caused damage to account for the thickness debit effect. The paper aims to discuss these issues.

The model uses the simple Norton type creep relation to describe the creep rate evolution. The damage evolution caused by void is taken to be stress controlled. The load baring area changes are calculated with the consideration of oxidation and void evolutions.

Simulations on specimens with different thickness from 3.0 to 0.3 mm are carried out. The results show that the present model can reproduce the decrease of the creep strength with the decreases of the specimen thickness. The damage plays a major role in the creep behavior of the thick specimen. Both the damage and the oxidation are important for the thin specimen which should be paid attention to during the calculation of the creep response of the thin-wall turbine blade.

A model is proposed to account for the thickness debit effect on the creep behavior of Ni-based superalloys. Both oxidation influence and void caused damage are introduced. The simulation results show the capability of the model to reproduce the thickness debit effect.

AS aircraft become aerodynamically cleaner, an ever‐increasing proportion of the drag becomes pure skin drag. The known laws of the drag of flat plates enable the friction drags which occur at the Reynold's Numbers met in high‐speed flight to be approximately calculated. In addition, the very important effects of surface roughness which occur at high speeds may be assessed in a practical manner for aircraft from the known data on flat plates.

Porosity is a commonly analyzed defect in the laser-based additive manufacturing processes owing to the enormous thermal gradient caused by repeated melting and solidification. Currently, the porosity estimation is limited to powder bed fusion. The porosity estimation needs to be explored in the laser melting deposition (LMD) process, particularly analytical models that provide cost- and time-effective solutions compared to finite element analysis. For this purpose, this study aims to formulate two mathematical models for deposited layer dimensions and corresponding porosity in the LMD process.

In this study, analytical models have been proposed. Initially, deposited layer dimensions, including layer height, width and depth, were calculated based on the operating parameters. These outputs were introduced in the second model to estimate the part porosity. The models were validated with experimental data for Ti6Al4V depositions on Ti6Al4V substrate. A calibration curve (CC) was also developed for Ti6Al4V material and characterized using X-ray computed tomography. The models were also validated with the experimental results adopted from literature. The validated models were linked with the deep neural network (DNN) for its training and testing using a total of 6,703 computations with 1,500 iterations. Here, laser power, laser scanning speed and powder feeding rate were selected inputs, whereas porosity was set as an output.

The computations indicate that owing to the simultaneous inclusion of powder particulates, the powder elements use a substantial percentage of the laser beam energy for their melting, resulting in laser beam energy attenuation and reducing thermal value at the substrate. The primary operating parameters are directly correlated with the number of layers and total height in CC. Through X-ray computed tomography analyses, the number of layers showed a straightforward correlation with mean sphericity, while a converse relation was identified with the number, mean volume and mean diameter of pores. DNN and analytical models showed 2%–3% and 7%–9% mean absolute deviations, respectively, compared to the experimental results.

This research provides a unique solution for LMD porosity estimation by linking the developed analytical computational models with artificial neural networking. The presented framework predicts the porosity in the LMD-ed parts efficiently.

When a cascade of blades is tested in a wind‐tunnel, the principal measurements are directed towards the determination of the characteristics of each streamline in the plane of the exit from the blading. Information is thus derived concerning the behaviour of each blade, so that the losses may be identified and analysed, and the way opened for an improvement in the efficiency.

FEW visitors to the Business Efficiency Exhibition held in London a few weeks ago can be in any doubt that electronic “brains” and other electro‐mechanical developments will be used more widely in business in future for preparing up‐to‐date records of production and sales and for doing such laborious, time‐consuming tasks as the bookkeeping necessary in the banks.

THE need to increase the productivity of British industry is a common topic and when it is discussed the more economic use of manpower is inevitably raised. What is often lost sight of is the fact that future gains of productivity will be derived, as they were in the past, from a wider use of better machines rather than from more intensive effort by human beings. Such machines are expensive. Some of them, like the sophisticated machine tools described by the grandiose name of ‘machining centres’, are extremely costly.

Purpose – To predict the existence of the aquifer, search the location, position, thickness, deep and dissemination of subsurface aquifer and predict the environmental condition by conducting the groundwater/aquifer condition.

Design/Methodology/Approach – The way to know the state of groundwater aquifers, one of which is the Geo-electric Method by using the Resistivity Schlumberger Method.

Findings – Pouple activities are not many effects to the groundwater but more time depend on the development, it can many influences to environmental conditions.

Research Limitations/Implications – The analysis is conducted to every point but on this research, it is on mentioned and taken from one sample only, it is HPR.

Practical Implications – In anticipation the effect of the development of the region in general, it is necessary to be able businesses for raw water, irrigation and Industry of the groundwater can be as well as how to control over the distribution and causes of infiltration into the soil.

Originality/Value – That is by measuring the resistivity and mapping dealer spread a layer of groundwater (aquifers) that an overview of the groundwater can be known.

IN 1955 Hamburger Flugzeugbau began to reconstruct its Finkenwerder plant and develop its aeronautical activities, following the period of in‐activity after the Second World War. Production began with an order from the West German Federal Defence Ministry for components for the S.N.C.A.N. 2501 Noratlas built under licence for the West German Air Force. Final assembly and flight testing of this twin‐engined transport were also carried out at Finkenwerder. The next stage of development involved participation in the European licence production of the Lockheed F.104G Starfighter, and in the design and construction of the Franco‐German C.160 Transall transport. By J 958, HFB had completed the project stage of the design of a turbojet airliner—the HFB 314. This was a short /medium‐range airliner designed to carry 70 tourist class passengers over ranges up to 1,250 miles. Although Hamburger Flugzeugbau had designed the aircraft in close co‐operation with Lufthansa, West Germany's largest airline, and were fully prepared to produce the aircraft in consort with other German or European companies, development costs would have amounted to some £5 million and since no Government financial support was forthcoming, the project was abandoned. Determined to reassert its authority as a design agency, HFB turned to the jet executive field in 1960 and designed the twin‐jet HFB 320 Hansa. The most distinctive feature of this aircraft is without doubt its sweptforward wing and it is this feature which is dealt with in detail in this article. The decision to utilize such a wing was based to some extent on Hamburger Flugzeugbaus‘ technical experience in the development of the Junkers Ju 287 sweptforward wing dating back to the Second World War. The HFB 320 Hansa is powered by two General Electric CJ 610–1 turbo‐jets, each of which has a weight of 355 lb. and a thrust of 2,850 lb. The engine's eight‐stage axial compressor has a mass flow of 565 at. ft. I sec. at 16,500 r.p.m. At gross weights of 16,000 to 18,000 lb., the Hansa will cruise at 500 m.p.h. over ranges up to 1,600 miles with full reserves. Well over 2,000 hours of model testing have been carried out in wind tunnels at the Aerodynamische Versuchsanstalt, (Goettingen), National Luchten Ruimtvaartlaboratorium (Amsterdam), Torrejon (Madrid), Emmen (Switzerland) and Modane (France).‐ Static testing is underway on an airframe structural specimen including: test for maximum cabin pressure, windshield strength test—bird impact, investigation of ground and landing loads, and investigation of loading at the extremes of the flight envelope. Later this summer, HFB will commence a programme of loading tests of a dynamic test airframe utilizing the water tank technique, involving pressurization cycles and gust loading to simulate 50,000 flights. Assembly of the first prototype HFB 320 Hansa was completed on March 18, 1964, and was followed by ground resonance tests, and engine ground’ running prior to the aircraft's maiden flight on April 21. The prototype, which carries extensive flight test instrumentation and is not equipped with the production‐type cabin, made its first public appearance at the Deutsches Luftfahrtschau at Hanover‐Langenhagen a few days later. The full flight test programme is currently being pursued.

MORE cheering news about work study. In the Daily Express the following appeared: ‘Inflation has hit the State‐aided Remploy factories manned by wore than 6,000 disabled workers. But the workers of the 91 factories have wiped out—by increased efficiency—£124,000 of £271,000 rise in costs in the financial year up to the end of March.’

In previous articles in this series, an effort has been made to foresee the trends over the next two decades. In this last article, some aspects are discussed where prediction is virtually impossible, and the most one can do is to speculate. One thing only is quite certain; that is that one day all fossil fuels will be exhausted and that we shall then have to rely on alternative ‘everlasting’ sources. The big doubts are what these alternatives will be, and how long the period is before exhaustion of fossil fuels occurs.