THE DEVELOPMENT OF A NOVEL ELECTRO-MAGNETIC FORCE MICROSCOPE

This thesis describes the development of a new type of Magnetic Force Microscope (MFM) probe based on a unique electromagnetic design. In addition the design, construction and testing of a new MFM system, complete in both hardware and software, is also described. The MFM allowed initial tests on prototypes of the new probe, and is to provide a base for future new probe integration. The microscope uses standard MFM micro-cantilever probes in static modes of imaging. A new computer hosted DSP control system, software, and its various interfaces with the MFM have been integrated into the system. The system has been tested using standard probes with various specimens and satisfactory results have been produced. A novel probe has been designed to replace the standard MFM magnetic coated tip with a field generated about a sub-micron aperture in a conducting film. The field from the new probe is modelled and its imaging capability investigated, with iterative designs analysed in this way. The practical construction and potential problems therein, of the probe are also considered. Test apertures have been manufactured, and an image of the field produced when operating is provided as support to the theoretical designs. Future methods of using the new probe are also discussed, including the examination of the probe as a magnetic write mechanism. This probe, integrated into the MFM, can provide a new method of microscopic magnetic imaging, and in addition opens a new potential method of magnetic storage that will require further research

Discovery of a lipid synthesising organ in the auditory system of an insect

Weta possess typical Ensifera ears. Each ear comprises three functional parts: two equally sized tympanal membranes, an underlying system of modified tracheal chambers, and the auditory sensory organ, the crista acustica. This organ sits within an enclosed fluid-filled channel–previously presumed to be hemolymph. The role this channel plays in insect hearing is unknown. We discovered that the fluid within the channel is not actually hemolymph, but a medium composed principally of lipid from a new class. Three-dimensional imaging of this lipid channel revealed a previously undescribed tissue structure within the channel, which we refer to as the olivarius organ. Investigations into the function of the olivarius reveal de novo lipid synthesis indicating that it is producing these lipids in situ from acetate. The auditory role of this lipid channel was investigated using Laser Doppler vibrometry of the tympanal membrane, which shows that the displacement of the membrane is significantly increased when the lipid is removed from the auditory system. Neural sensitivity of the system, however, decreased upon removal of the lipid–a surprising result considering that in a typical auditory system both the mechanical and auditory sensitivity are positively correlated. These two results coupled with 3D modelling of the auditory system lead us to hypothesize a model for weta audition, relying strongly on the presence of the lipid channel. This is the first instance of lipids being associated with an auditory system outside of the Odentocete cetaceans, demonstrating convergence for the use of lipids in hearing

Carbon fibre reinforced plastic EOL : protecting remanufacturing status and life cycle route analysis

For a remanufacturing industry to take hold within society it is critically important that people understand the term remanufacture. While general public remanufacturing awareness problems of course exist, within academia and industry remanufacturing awareness issues can also exist. It is also true that academia and industry are both directly involved in strategies to reuse carbon fibre reinforced plastic (CFRP) waste obtained from the manufacturing process (cut offs for example), and that obtained from end of life (EOL) CFRP products such as aircraft. Through a lack of awareness, remanufacturing terminology is often used to describe creating a new product from an existing one within these sectors. This of course is a problem for two main reasons. Firstly, remanufacturing is a standalone process, having its own protocols and criteria that must be adhered to and secondly, if the term remanufacture is not used correctly, a lack of awareness of remanufacture will inevitably continue. This paper presents a brief description of the efforts by industry and academia to create new products from waste and EOL CFRP. It goes on to mention why remanufacture terminology although used is not generally applicable to describe these products. Further, to help stop the potential spread of remanufacturing terminology being used wrongly in this growing sector (which only seeks to water down true remanufacturing meaning) and to increase remanufacturing profile in general a product identification flow chart is presented. The flow chart has two main purposes, 1) it informs the user involved in product EOL whether they have remanufactured, recycled, reconditioned, repaired or re-used a product and 2) it allows for a very simple and efficient method to analyse any previously owned (i.e. not brand new) product in terms of the type of EOL treatment performed

Integration of remanufacturing issues into the design process

Remanufacturing is the process of returning a used product to like-new condition with a warranty to match. The efficiency and effectiveness of this process greatly depends upon product design; there are certain product properties that may have a positive or negative effect on steps of the remanufacturing process. The concept of 'design for remanufacture' or 'DfRem' is a design task dedicated to improving the remanufacturability of a product. However, it would appear that very few products are currently designed for remanufacture and the reasons behind this have yet to be fully explored. This paper provides an overview of the problem and a discussion of some of the preliminary findings of a study aimed at improving designers' ability to carry out DfRem. The findings provide an early indication of some of the factors affecting the integration of DfRem into the design process

Ultrasonic sonar system for target localization with one emitter and for receivers

This paper presents an ultrasonic active sonar system in air constituting one emitter and four receivers. Target localization is achieved by means of intersection of four ellipsoids defined by the time of flight between emission and reception of the signal reflected by the target. This paper shows a proof of concept of the localization principle through some localization tasks conducted in a laboratory environment. The position of a spherical target is determined with an error between 1cm and 7cm depending on receiver configuration and target position. The purpose of the fully developed sonar system is to assist drones and robots in their autonomous navigation

Bio-inspired sound localization sensor with high directional sensitivity

MEMS microphones inspired by Ormia ochracea are constrained by their reliance on the resonant behavior of the system, forcing designers to compromise the goal of high amplification of directional cues to operate across the audio range. Here we present an alternative approach, namely a system optimized for the maximum amplification of directional cues across a narrow bandwidth operating purely as a sound-localization sensor for wide-band noise. Directional sensitivity is enhanced by increasing the coupling strength beyond the 'dual optimization' point, which represents the collocation of a local maximum in directional sensitivity and a local minimum in non-linearity, compensating for the loss of the desirable linearity of the system by restricting the angular range of operation. Intensity gain achieved is 16.3 dB at 10° sound source azimuth with a linear directional sensitivity of 1.6 dB per degree, while linear directional sensitivity in phase difference gain shows a seven fold increase over the 'dual optimization' point of 8 degrees phase difference per degree change in azimuthal angle

Hearing ability decreases in ageing locusts

Insects display signs of ageing, despite their short lifespan. However, the limited studies on senescence emphasize longevity or reproduction. We focused on the hearing ability of ageing adult locusts, Schistocerca gregaria. Our results indicate that the youngest adults (2 weeks post-maturity) have a greater overall neurophysiological response to sound, especially for low frequencies (<10 kHz), as well as a shorter latency to this neural response. Interestingly, when measuring displacement of the tympanal membrane that the receptor neurons directly attach to, we found movement is not directly correlated with neural response. Therefore, we suggest the enhanced response in younger animals is due to the condition of their tissues (e.g. elasticity). Secondly, we found the sexes do not have the same responses, particularly at 4 weeks post-adult moult. We propose female reproductive condition reduces their ability to receive sounds. Overall our results indicate older animals, especially females, are less sensitive to sounds

Optimization of a bio-inspired sound localization sensor for high directional sensitivity

Miniaturization of sound localization sensors arrays is heavily constrained by the limited directional cues in intensity difference and phase difference available at the microscale. Micro-Electro Mechanical System (MEMS) sound localization sensors inspired by the auditory system of Ormia ochracea offer a potential solution to this problem by the apparent amplification of the available intensity and phase difference between the measurement points. An inherent limitation of these existing systems is that significant amplification of these cues is only available at or close to one of the resonant frequencies of the device, severely limiting it application as a directional microphone. Here we present the process of optimization of a sound localization sensor for the maximum amplification of directional cues across a narrow bandwidth, increasing the signal to noise ratio and the reading accuracy for sound localization measurements

Note Taking in VR: The Forearm Keyboard

This work presents and evaluates a forearm keyboard that allows users to enter textual data using a natural full-handed typing mechanism for virtual reality head-mounted display environments. Should the issues noted with the keyboard during the study be solved, the keyboard would compare favourably with others seen in the literature

What makes cleaning a costly operation in remanufacturing?

Part of: Seliger, Günther (Ed.): Innovative solutions : proceedings / 11th Global Conference on Sustainable Manufacturing, Berlin, Germany, 23rd - 25th September, 2013. - Berlin: Universitätsverlag der TU Berlin, 2013. - ISBN 978-3-7983-2609-5 (online). - http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-40276. - pp. 219–223.Product remanufacturing is a widely accepted product reuse strategy in most industries due to its unique advantage of retaining a greater portion of added value in the initial manufacturing stage. Remanufacturing involves a sequence of operations including disassembly, cleaning, inspection, parts replacement, reassembly and testing. Previous research has shown that the cost of cleaning is only second to the cost of parts replacement. The objective of this study is to illustrate the significance of the cleaning operation in automotive remanufacturing and to identify the factors influencing the cost of the cleaning process. Case studies on four UK remanufacturers, three automotive and one copier, were carried out. Seven key factors causing high cleaning costs were identified and categorised under two dimensions. These are the technical nature of the products and processes of cleaning and the business nature of the remanufacturer