Active Thermal Sensor for Improved Distributed Temperature Sensing in Haptic Arrays

The efficacy of integrating temperature sensors into compliant pressure sensing technologies, such as haptic sensing arrays, is limited by thermal losses into the substrate. A solution is proposed here whereby an active heat sink is incorporated into the sensor to mitigate these losses, while still permitting the use of common VLSI manufacturing methods and materials to be used in sensor fabrication. This active sink is capable of responding to unknown fluctuations in external temperature, that is, the temperature that is to be measured, and directly compensates in real time for the thermal power loss into the substrate by supplying an equivalent amount of power back into the thermal sensor. In this paper, the thermoelectric effects of the active heat sink/thermal sensor system are described and used to reduce the complexity of the system to a simple one-dimensional numerical model. This model is incorporated into a feedback system used to control the active heat sink and monitor the sensor output. A fabrication strategy is also described to show how such a technology can be incorporated into a common bonded silicon-on-insulator- (BSOI-) based capacitive pressure sensor array such as that used in some haptic sensing systems

A comparison of the manufacture and mechanical performance of porous aluminium and aluminium syntactic foams made by vacuum-assisted casting

This paper compares key aspects of the manufacture and mechanical performance of porous Al, made by replication using salt beads, and structurally similar syntactic metal foams, made by replacing the salt with porous, expanded glass particles. Despite significant increases in stiffness, strength and energy absorbed, power law relationships between properties and relative density demonstrate that adding expanded glass particles is a less efficient route to increasing performance than increasing the metal fraction. That said, merit indices do indicate that 20% savings in mass are possible for stiff beams by substituting aluminium with syntactic metal foams. The manufacturing process for syntactic metal foams is shown to be simpler, driven by the lower thermal mass of the expanded glass particles and no requirement to dissolve a space holder from the structure. The balance of good performance and good manufacturability demonstrated herein, coupled with predicted low costs for raw material and manufacturing, highlights the scope for syntactic metal foams containing weak expanded glass particles to be researched and developed more widely

Self-Monitoring, Self-Healing Biomorphic Sensor Technology

The deployment of autonomous sensors within electronic systems for both existing and emerging markets requires an increase in the reliability, security and dependability of the associated data generated. The availability of intelligent sensors that can self-adapt and ultimately self-heal would be a key step towards this objective. This paper presents ideas associated with the utilisation of sensor self-test principles and software algorithms able to generate sensor prognostics and drive adaptation, compensation and self-healing functions. Major initiatives supported both within Europe and further afield to migrate processing power to the 'Edge', deploy 5G technologies and integrate Artificial Intelligence across the system hierarchy provide technological platforms to deliver many of these concepts. An example associated with simple printed electrodes targeting corrosion detection and potentially the detection of hydrogen is presented in the context of a step towards full biomorphic capability

Liquid-like behaviour of gold nanowire bridges

A combination of Focused Ion Beam (FIB) and Reactive Ion Etch (RIE) was used to fabricate free standing gold nanowire bridges with radii of 30 nm and below. These were subjected to point loading to failure at their mid-points using an Atomic Force Microscope (AFM), providing strength and deformation data. The results demonstrate a dimensionally dependent transition from conventional solid metallic properties to liquid-like behaviour including the unexpected reformation of a fractured bridge. The work reveals mechanical and materials properties of nanowires which could have significant impact on nanofabrication processes and nanotechnology devices such as Nano Electro Mechanical Systems (NEMS)

Measurement and modelling of the elastic defection of novel metal syntactic foam composite sandwich structures in 3-point bending

This paper presents a process for creating syntactic metal foam sandwich structures which, for the first time, manufactures both the syntactic foam core and metal face sheets in a single step. Unlike previous research, the face sheets are made from the same material, are integral with the sandwich structure and are relatively thick compared to the core. Via comparison with experimental measurements in 3-point bending, it is shown that accurate prediction of the elastic deformation of these sandwich structures necessitates FE-based modelling, but that the methodology is simple. A reliance on predictions from established analytical models, which have proven themselves accurate for foam sandwiches with thin face sheets, leads to significant over-estimations of the stiffness. Modelling, based on the FEA approach developed herein, shows that mass savings between 20 and 30% are achievable for these novel structures, produced using simple and low cost casting methods, but are dependent upon the deflection response required

Compact viscometer prototype for remote in-situ analysis of sludge

On the Sellafield site there are a number of legacy storage tanks and silos containing sludge of uncertain properties. While there are efforts to determine the chemical and radiological properties of the sludge, in order to clean out and decommission these vessels the physical properties need to be ascertained as well. Shear behaviour, density and temperature are the key parameters to be understood before decommissioning activities commence. However, limited access, the congested nature of the tanks and presence of radioactive, hazardous substances severely limit sampling and usage of sophisticated characterisation devices within these tanks and therefore these properties remain uncertain. This paper describes the development of a cheap, compact and robust device to analyse the rheological properties of sludge, without the need to extract materials from the site in order to be analysed. Analysis of a sludge test material has been performed in order to create a suitable benchmark material for the rheological measurements with the prototype. Development of the device is being made with commercial off the shelf (COTS) components and modern rapid prototyping techniques. Using these techniques an initial prototype for measuring shear parameters of sludge has been developed, using a micro-controller for remote control and data gathering. The device is also compact enough to fit through a 75 mm opening, maximising deployment capabilities

Data for: The stability and degradation of PECVD fluoropolymer nanofilms

Ellipsometry and AFM scan dataThermal cycling dataTHIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Improving the kinematic accuracy of a collaborative continuum robot by using flexure-hinges

Within various unstructured industrial environments, there is often the requirement to conduct remote engineering tasks, such as sampling the structure for analysis prior to decommissioning. Most existing tools are simply not dexterous enough to fulfil this task, and thus new technology is required. We describe here a simple, lightweight, and water-resistant collaborative dual-arm continuum robot system which can aid in this task. To improve the kinematic accuracy of the system, a class of flexible hinges have been combined with a conventional continuum robot configuration. The thickness and width of said flexible hinges can be adjusted to adapt to various tasks. Kinematic and stiffness models have further been developed, incorporating the influence of these flexible hinges. A set of experiments have been conducted to validate the proposed model and demonstrate the advantages of the platform. It was found that the kinematic accuracy of the continuum robot can be improved by a factor of around 10 with the aid of said hinges