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This paper aims to offer the aerodynamic testing community a new procedure for manufacturing high-quality aerodynamic probes suitable for 3D flow measurements with consistent geometry and calibration by taking advantage of the additive manufacturing technology.

The design methodology combines the advantages and flexibilities of computer aided design (CAD)/computer aided manufacturing (CAM) along with the use of computational fluid dynamics to design and analyse suitable probe shapes prior to manufacturing via rapid prototyping.

A viable procedure to design and possibly batch manufacture geometrically accurate pneumatic probes with consistent calibration is shown to be possible through this work. Multi-jet modelling prototyping methods with wax-based support materials are found to be a cost-effective method when clean and long sub-millimetre pressure channels are to be cut.

Utilisation of the geometry consistency that is made possible by 3D printing technology for the design and development of pneumatic probes is described. It is suggested that the technique could lead to batch production of identical probes, thus avoiding precious time of a skilled labourer and elaborate individual calibration requirement.

RENISHAW are innovators in metrology, the science of measurement. Their core business is based on 3‐dimensional tough‐trigger probe technology, the original probe having been invented by the Group's chairman and chief executive, David McMurtry in the early 1970's when he was employed by the Aero‐Engine Division of the Rolls‐Royce Group at Filton. Particular components, under inspection on a Co‐ordinate Measuring Machine (CMM) would deflect when touched with a solid probe, which gave inaccurate readings. The touch‐trigger probe resulted which gave a signal with low contact force on the stylus, and which was repeatable. The touch‐trigger probe may be regarded as a sophisticated omni‐directional switch where changes in contact circuit characteristics are monitored by an interface unit for feeding to a machine's control. By 1979 nearly all CMMs incorporated Renishaw probes as standard equipment and annual sales had reached £1,000,000.

The purpose of this paper is to propose and optimize plastic optical fiber (POF) probe with macro-bending biconical tapered structure for the relative humidity (RH) sensing.

In this study, the principle is the evanescent wave power modulated by the ambient humidity. The probe is fabricated by using fused biconical taper and heat-setting method and then coated with a fluorescent moisture-sensitive film.

The probe’s sensing performance can be optimized by changing the probe’s curvature radius, biconical tapered transition length and taper waist diameter. The result shows that the sensitivity of the probe is up to 1.60 and 3.40 mV/ per cent, respectively, at low humidity (10-45 per cent) and high humidity (45-90 per cent). Also, this probe has good linearity, repeatability, photostability and long-term stability.

The proposed probe can improve the sensitivity and linearity of RH sensing without complex devices, which is necessary for mass production, remote measurement and convenient operation.

POF probe with macro-bending biconical tapered structure is investigated in this paper, which is proved to be effective in improving the sensitivity and linearity.

A survey is made of the instruments and methods used to measure total and static pressure and direction in three‐dimensional flow. Comparative tests in a towing tank of two designs of live‐orifice pitot‐type probe showed the advantage, within a limited range of flow inclination, of the instrument with independent static pressure orifices. Speed and angle of flow characteristics are Riven for these two probes, which differed in the shape of head.

Design features and characteristics of conventional, modified and shielded total‐pressure probes are briefly discussed, and compared with new shielded instruments of simple construction which combine smallness of size with adequately fast response to pressure changes. Tests at air speeds up to 280 ft./sec. showed that a probe featuring a total‐traversing cylinder with single orifice inside a tubular shield will register total pressure to within 1 per cent of the dynamic pressure up to inclinations of the flow of ±28 deg., the error in the range ±22 deg. being less than 0.5 per cent. The response time of the instrument under a suddenly applied air pressure of 500 mm. W.G. was less than 60 seconds when linked to a Betz projection manometer. If the inner cylinder is replaced by a central sting, the range of insensitivity to flow inclinations is increased to ±45 deg., the error being less than 0·5 per cent of the dynamic pressure. The response time of this probe under 500 mm. W.G. air pressure was approximately 100 seconds. Still simpler versions of the instruments described are under development.

Automatic in‐circuit testing is a cost effective facility for not only testing assembled printed circuit boards but for providing component level diagnostics very quickly with an average PCB test time of less than 30 seconds. The in‐circuit tester relies on a customised fixture (essentially a bed‐of‐nails) to interface particular PCBs to the system and a computer programme to control the hardware to test all the individual components on the PCB to their own specification irrespective of how the circuitry is configured. So if all the individual components work and are interconnected correctly, the complete assembly should function correctly. Traditionally the fixture requirements for most PCBs have been straightforward. In general, components are mounted on only one side of the board allowing easy access to the other side where all the tracks may be accessed by a bed of nails. However, the introduction of surface mount technology introduces mechanical restraints on this concept. Components can be mounted on both sides of the PCB, possibly causing an access problem. Not all circuit interconnections may be available on a single side of the PCB, necessitating dual side fixturing. The pitch of components together with pad and track sizes has dramatically reduced, possibly requiring the use of smaller test probes and certain SMDs do not allow direct probing at all. All these things can present problems but they do not mean that in‐circuit testing is no longer the solution to the test and repair problem. On the contrary, it is particularly well suited to the production problems being experienced by manufacturers. And where components are difficult to remove and replace on a PCB, it is particularly important that the fault diagnosis is to component level. This paper describes the problem in detail and goes on to demonstrate that if a code of practice is followed within the design of a new PCB, then there need not be a problem. Much can be achieved very simply within the design that can improve the testability of PCBs so that in‐circuit testing remains a very cost effective system. Experience demonstrates that most designs could be fixtured with traditional techniques and that means cheap and reliable fixturing.

High-altitude ice crystals (HAICs) are causing one in-flight event or more per month for commercial aircraft. The effects include preventing air data probes (pitot pressure and total air temperature in particular) from functioning correctly and causing engines to roll back and shut down. The purpose of this study is to describe the process used by the National Research Council Canada (NRC) to develop and test a particle detection probe (PDP). The probe mounts on the fuselage of aircraft to sense and quantify the ice crystals in the environment.

The probe was demonstrated on the NRC Convair and Airbus A340 research aircraft as part of the European Union HAIC programme. The probe was ruggedised, adapted for easy installation in standard aircraft fittings and tested in a variety of conditions for longevity and endurance.

Efforts to achieve the safety requirements for flight on aircraft are discussed. The challenges, surprises and opportunities for testing on which the development group is capitalised are also presented.

It was demonstrated that the detectors gave signals proportional to the ice crystal content of clouds, and results demonstrating the functionality of the probe are presented.

This paper describes the multi-year process of developing the NRC PDP from a test cell sensor for detecting engine exhaust contaminants on an aircraft ice crystal detection probe. The work included over 20 flight tests on NRC aircraft and the Airbus HAIC test programme.

The present work aims to deal with ultrasound-assisted organic pigment (phthalocyanine blue and green) dispersion and its comparison with the conventional approach.

Ultrasound is expected to give beneficial results based on the strong shear forces generated by cavitational effects. The dispersion quality for preparation using an ultrasound-based method has been compared with dispersion obtained using high-speed dispersion mill. Effects of different operating parameters such as probe diameter and use of surfactants on the physical properties of dispersion and the colour strength have been investigated. Calculations for the energy requirement for two approaches have also been presented.

The use of sodium dodecyl sulphate and Tween 80 surfactants shows better performance in terms of the colour properties of dispersion prepared in water and organic solvent, respectively. Ultrasound gives better dispersion quality as compared to the conventional approach.

The present work presents a new approach of ultrasound-assisted dispersion of phthalocyanine blue and green pigments. Understanding into the effect of surfactants and type of solvent also presents new important design-related information.

Special probes were developed to test rotor blades for fatigue cracks. These probes utilize ultrasonic surface waves which are highly sensitive to fatigue cracks. The dimensions of the probes were kept small to make possible the testing of blades without the necessity of dismounting. The probes are built up from conventional commercial probes by attaching some small auxiliary equipment to them, which is very easy to manufacture. Searching blades with these probes is more reliable and less time‐consuming than with previously available methods.

The detailed flow behaviour around a four—hole Cobra Pitot pressure probe, developed by the Commonwealth Scientific and Industrial Research Organization, Australia, (CSIRO), to determine the pressure and the velocity components in three dimensional single‐phase/multi‐phase fluid flow, is investigated computationally. The incompressible steady state Navier—Stokes equations are solved numerically using a general purpose computational fluid dynamics (CFD) code developed at CANCES. Computational results are presented for representative probe pitch and yaw angles at a Reynolds number = 2 × 10³, emphasising the pressure distribution and flow separation patterns on the probe tip adjacent to the pressure ports. Quantitative comparison of the computational simulation to experimental results is done by comparing experimental calibration data to numerically computed pressure responses. The topological features of the near tip flow behaviour are visualised using critical point concepts and three dimensional streamlines. Additional qualitative comparison to experiment is discussed using data from a preliminary experimental investigation using surface oil film visualisation techniques, where available. Conclusions are drawn concerning the near tip flow behaviour, the good level of agreement between the numerical results and experimental data and the effectiveness of using a computational analysis to provide accurate detail useful for engineering design purposes.