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The purpose of this paper is to present a stretched backboneless continuum manipulator, which aims to provide sufficient inner room for potential transportation of objects or fixture of necessary devices, and to reduce the number of motors for reduction of the weight of the system.

A mathematical model of the presented manipulator is established in this paper. To verify the presented theory, the position of the free end was recorded by a high-resolution digital camera in experiment. According to the comparison of experimental values and theoretical values, the error is less than 2.5 per cent. It shows that the mathematical model and theoretical analysis are reasonable; the presented continuum manipulator can reach to desired postures and positions.

This paper presents a new stretched backboneless continuum manipulator supported and driven by cannula tendons. The cannula tendons are composed of rubber tubes and glass fibers. The upper section and the lower section of the presented manipulator are driven by same motors. For steering the manipulator, switched driving strategy is developed based on the presented kinematics model. The presented manipulator possesses six degrees of freedom (DOFs) and has good performance in dealing with complex working environment. The experiment verifies the presented driving strategy.

The presented backboneless continuum manipulator has only two sections and is supported by cannula tendons. Extending this structure to further more sections is a challenge and is left for future research.

The value of this study is to propose a stretched backboneless continuum manipulator, which can provide inner room as large as possible for potential usage and halve the number of motors, for which a switched driving strategy is put forward. As a result, the weight and complexity of the manipulator are decreased. The presented manipulator is able to move in potential complex environments and approach its objects in different postures in virtue of its high flexibility and its six DOFs.

TEST bed equipment plays no small part in the comparatively high standard of efficiency of the modern aero‐engine, and a lot of time has been given to the careful study of engine test requirements by equipment designers.

FLYING, in common with all means of transport, is affected by adverse weather conditions, but the necessity of aeroplanes maintaining flying speed introduces a major difficulty of its own. The older forms of transport are able, in the last resort, to evade their difficulties by coming to a dead stop. An aeroplane must, literally, fly in the face of its difficulties. It must fly blind in clouds and perhaps land in fog. Over and above this, flight under certain meteorological conditions introduces a danger unique to aircraft. Ice may deposit at all leading edges and grow to windward, at critical regions of the relative airflow, in shapes which increase drag and seriously decrease lift. The accumulated ice adds to the weight. Unsymmetrical ice deposits on the airscrew blades cause dangerous engine vibrations which can only be kept in check, if at all, by throttling back at the expense of thrust. Venturis and pressure head orifices become blocked with ice, rendering the instruments they serve useless. External controls may become jammed. In short, many adverse factors to prevent flight may be brought into play simultaneously by the mere fact that particular meteorological conditions have been encountered.

THE non‐metallic materials used in aircraft construction consist of a large number of different substances, to enter into any detailed discussions of which would occupy a volume of many pages. They are, however, conveniently classifiable into groups, and the reader will find, in what follows, some notes upon each group.

This from a poet whose identity we have long since forgotten suggests the paramountcy of the present; to live to the full today's day and exact from it all the vitality and value its few fleeting hours contain. There is profit to be had, however, at given times, such as events that are landmarks, at the ends of periods as now, the end of a year, from looking back and noting what has passed.

SUPERCHARGED aero engines are more or less a post‐war invasion into the practical side of aero‐engine design. The problem of power boosting for internal combustion engines, especially aero engines, has for several years engaged the attention of engine designers, with the result that to‐day quite a number of engines are produced with superchargers as an integral part of the standard equipment. Various types of superchargers have been tried, such as the reciprocating pump, Roots Blower, exhaust‐driven turbo compressor, and the gear‐driven centrifugal form of blower. The last‐named is the type most commonly used in this country at the present time.

The UK Medical Research Council's Neurological Prosthesis Unit was formed on 1 October 1968. In this review, Peter Donaldson, who has been with the unit from the beginning, reflects on what seem to him to be the most important contributions to implant technology from the unit, and suggests some possible developments for the future.

This study aims to investigate the morphology and physicochemical properties of BiOBr/Polyvinylidene fluoride (PVDF) composite membranes and the differences in the properties of BiOBr/PVDF composite membranes made by adding different precursor ratios during the casting process.

In this paper, sodium bromide and Bi(NO3)3 were used as precursors for the preparation of BiOBr photocatalysts, and PVDF membranes were modified by using the phase conversion method in conjunction with the in situ deposition method to produce BiOBr/PVDF hydrophilic composite membranes with both membrane separation and photocatalytic capabilities.

The characterization results confirmed that the composites were successfully and homogeneously co-mingled in the PVDF membranes. The related performance of the composite membrane was tested, and it was found that the composite membrane with the optimal precursor incorporation ratio had good photocatalytic efficiency and antipollution ability; the removal efficiencies of methyl orange, rhodamine B and methylene blue were 80.43%, 85.02% and 86.94%, respectively, in 2.5 h. The photocatalytic efficiency of composite membranes with different precursor ratios increased and then decreased with the increase of the precursor addition ratio.

The composite membrane is prepared by phase conversion method with in situ deposition method, and the BiOBr material has unique advantages for the degradation of organic dyes. The comprehensive experimental data can be known that the composite membrane prepared in this paper has high degradation efficiency and good durability for organic dyes.

The purpose of this paper is based on the response surface method, the authors determined the conditions for achieving the optimum rubber-sealing performance by using the maximum contact stress as the response value.

A two-dimensional model of a compression packer rubber was established by finite-element analysis software. Under the single axial load of 53.85 MPa, the four single factors of the end-face inclination angle, subthickness, height of rubber and friction coefficient of the rubber were analyzed.

Results show that the optimum sealing performance of the rubber tube is achieved when the end-face angle is equal to 45º and the thickness of the rubber tube is 9 mm. The response surface designed by Box–Behnken shows that the sealing performance of the rubber tube is the optimum when the end-face inclination angle is 48.1818°, the subthickness is 9 mm, the height of rubber is 90 mm and the friction coefficient is 0.1. Verification test results show that the model is reliable and effective.

Packer operations are performed downhole, and research on real experiments is limited. In this work, the feasibility of such experiments is determined by comparing finite-element modeling with actual experiments, and the results have guiding significance for actual downhole operations.