Fibre Bragg grating temperature sensors for high-speed machining applications

In high-speed grinding research, it is required to measure temperature within the workpiece. Present techniques are thermocouple based, and often suffer from excessive electrical noise on the signal. This thesis presents a number of novel and existing optical sensing devices that overcome this limitation and also, in some cases, offer greater performance. The optical sensors are fibre Bragg grating based and the optical techniques used to interrogate that sensor include DWDM, WDM, athermic grating, tuneable grating and coupler. Optical fibre devices are simpler to place in situ prior to the machining tests and they offer faster response and greater sensitivity than was previously possible. Results are presented from machining tests and the new devices are compared with each other and thermocouple based techniques. A method to relate internal measured temperature to machined surface temperature is also demonstrated in the context of high-speed machining

Towards a Model Based Sensor Measurement Variance Input for Extended Kalman Filter State Estimation

In this paper, we present an alternate method for the generation and implementation of the sensor measurement variance used in an Extended Kalman Filter (EKF). Furthermore, it demonstrates the limitations of a conventional EKF implementation and postulates an alternate form for representing the sensor measurement variance by extending and improving the characterisation methodology presented in the previous work. As presented in earlier work, the use of surveying grade optical measurement instruments allows for a more effective characterisation of Ultra-Wide Band (UWB) localisation sensors; however, in cluttered environments, the sensor measurement variance will change, making this method not robust. To compensate for the noisier readings, an EKF using a model based sensor measurement variance was developed. This approach allows for a more accurate representation of the sensor measurement variance and leads to a more robust state estimation system. Simulations were run using synthetic data in order to test the effectiveness of the EKF against the originally developed EKF; next, the new EKF was compared to the original EKF using real world data. The new EKF was shown to function much more stably and consistently in less ideal environments for UWB deployment than the previous version

The effects of acoustic vibration on fibroblast cell migration

Cells are known to interact and respond to external mechanical cues and recent work has 9 shown that application of mechanical stimulation, delivered via acoustic vibration, can be 10 used to control complex cell behaviours. Fibroblast cells are known to respond to physical 11 cues generated in the extracellular matrix and it is thought that such cues are important 12 regulators of the wound healing process. Many conditions are associated with poor wound 13 healing, so there is need for treatments/interventions, which can help accelerate the wound 14 healing process. The primary aim of this research was to investigate the effects of mechanical 15 stimulation upon the migratory and morphological properties of two different fibroblast cells 16 namely; human lung fibroblast cells (LL24) and subcutaneous areolar/adipose mouse 17 fibroblast cells (L929). Using a speaker-based system, the effects of mechanical stimulation 18 (0-1600Hz for 5 minutes) on the mean cell migration distance (μm) and actin organisation 19 was investigated. The results show that 100Hz acoustic vibration enhanced cell migration for 20 both cell lines whereas acoustic vibration above 100Hz acoustic vibration was found to 21 decrease cell migration in a frequency dependent manner. Mechanical stimulation was also 22 found to promote changes to the morphology of both cell lines, particularly the formation of 23 lamellipodia and filopodia. Overall lamellipodia was the most prominent actin structure 24 displayed by the lung cell (LL24), whereas filopodia was the most prominent actin feature 25 displayed by the fibroblast derived from subcutaneous areolar/adipose tissue. Mechanical 26 stimulation at all the frequencies used here was found not to affect cell viability. These results 27 suggest that low-frequency acoustic vibration may be used as a tool to manipulate the 28 mechano-sensitivity of cells to manipulate cell migration and which may be used to aid 29 wound repair

Towards Software Based Optical Communication Methods for the Assistance of Docking Autonomous Underwater Vehicles

The use of optical communications systems is prevalent in underwater robotics when short-range data transmission is required or preferred. This paper proposes a method of producing and testing an optical communications system for use in the assistance of optical docking for autonomous underwater vehicles (AUVs). It describes how the Simulink modelling environment was used to program and simulate a model of a transmitter, which was then implemented on a microcontroller. The transmitter model implemented on hardware was then used to produce an optical signal, which was sampled, logged and used to design a receiver model in Simulink. For signalling purposes, the experiment used a light-emitting diode (LED) with a driver circuit and photodiode based receiver. This simulated approach using real world data enabled the analysis of the system at every point during the process, allowing for a hardware in the loop style approach to be used in the receiver model design. Consequently, the Simulink Coder was used to produce the receiver model’s equivalent in C++ for later deployment. A benchmark was determined through experimentation to compare within future studies; the system was tested and found to operate effectively at distances between 1 m and 12 m in a controlled in air test environment

Temporal Monitoring of Simulated Burials in an Arid Environment Using RGB/Multispectral Sensor Unmanned Aerial Vehicles

For the first time, RGB and multispectral sensors deployed on UAVs were used to facilitate grave detection in a desert location. The research sought to monitor surface anomalies caused by burials using manual and enhanced detection methods, which was possible up to 18 months. Near-IR (NIR) and Red-Edge bands were the most suitable for manual detection, with a 69% and 31% success rate, respectively. Meanwhile, the enhanced method results varied depending on the sensor. The standard Reed–Xiaoli Detector (RXD) algorithm and Uniform Target Detector (UTD) algorithm were the most suitable for RGB data, with 56% and 43% detection rates, respectively. For the multispectral data, the percentages varied between the algorithms with a hybrid of the RXD and UTD algorithms yielding a 56% detection rate, the UTD algorithm 31%, and the RXD algorithm 13%. Moreover, the research explored identifying grave mounds using the normalized digital surface model (nDSM) and evaluated using the normalized difference vegetation index (NDVI) in grave detection. nDSM successfully located grave mounds at heights as low as 1 cm. A noticeable difference in NDVI values was observed between the graves and their surroundings, regardless of the extreme weather conditions. The results support the potential of using RGB and multispectral sensors mounted on UAVs for detecting burial sites in an arid environment

The detection of clandestine graves in an arid environment using thermal imaging deployed from an unmanned aerial vehicle

The Middle East is one of the world regions that has frequently suffered from armed conflicts that resulted in mass burials. However, the detection of clandestine graves in such an arid environment by deploying remote sensing payload on unmanned aerial vehicles (UAVs) has received little attention. The present study used a UAV equipped with a thermal sensor aimed at narrowing down the search area of possible gravesites in the arid climate of Kuwait. The enclosed research area, which includes both control and experimental mass graves, was imaged for 18 months. The variation in topsoil temperature and soil moisture between the graves and their surroundings was evaluated. The results of the analysis demonstrated the effectiveness of thermal imaging techniques in detecting heat produced from buried sheep carcasses and detecting the change in grave soil moisture for our research environment for 7 and 10 months, respectively. The buried animals significantly influenced the topsoil temperature (p = 0.044), while the height from which the images were captured had an insignificant effect on the measured temperature within the range tested (p = 0.985). Furthermore, there was a negative correlation (−0.359) between grave temperature and the calculated soil moisture. The results from these cost- and time-effective search methods presented in this study confirm their potential for the detection of burial sites in an arid environment

Acoustic Vibration Can Enhance Bacterial Biofilm Formation

This paper explores the use of low-frequency-low-amplitude acoustic vibration on biofilm formation. Biofilm development is thought to be governed by a diverse range of environmental signals and much effort has gone into researching the effects of environmental factors including; nutrient availability, pH and temperature on the growth of biofilms. Many biofilm-forming organisms have evolved to thrive in mechanically challenging environments, for example soil yet, the effects of the physical environment on biofilm formation has been largely ignored. Exposure of Pseudomonas aeruginosa to vibration at 100, 800 and 1600Hz for 48 hours, resulted in a significant increase in biofilm formation compared with the control, with the greatest growth seen at 800Hz vibration. The results also show that this increase in biofilm formation is accompanied with an increase in P. aeruginosa cell number. Acoustic vibration was also found to regulate the spatial distribution of biofilm formation in a frequency-dependent manner. Exposure of Staphylococcus aureus to acoustic vibration also resulted in enhanced biofilm formation with the greatest level of biofilm being formed following 48hours exposure at 1600Hz. These results show that acoustic vibration can be used to control biofilm formation and therefore presents a novel and potentially cost effective means to manipulate the development and yield of biofilms in a range of important industrial and medical processes

DigiArt: towards a virtualization of Cultural Heritage

DigiArt is a Europe-wide project aimed at providing a new, cost efficient solution to the capture, processing and display of cultural artefacts. The project will change the ways in which the public interact with cultural objects and spaces in a dramatic way. This project is unique in its collaborative approach: cultural heritage professionals working directly with electrical, mechanical, optical and software engineers to develop a solution to current issues faced by the museum sector. The innovations created by the engineers are driven by the demand of the cultural heritage sector. The diversity of the objects and spaces of the three test museums are challenging the engineers to provide a tool useful for a broad variety of indoor and outdoor museums in the future. This goes from using Unmanned Aerial Vehicle (UAVs or drones) to fly and record large sites, to using scanners to record fine jewellery. As a case study, we present here the use-case of Scladina Cave. At the end of the project, the Scladina Cave Archaeological Centre will offer two different visitor experiences. The first uses virtual reality, which will be available anytime, anywhere, to anyone with an internet connected device. The second will use augmented reality technologies within the cave site. The augmented reality visit of the cave will enhance the tour of Scladina by offering visits that would not be possible where it not for the augmented reality, where 3D objects and animations will contribute to offer a new 3D-immersive experience

Adapting astronomical source detection software to help detect animals in thermal images obtained by unmanned aerial systems

In this paper we describe an unmanned aerial system equipped with a thermal-infrared camera and software pipeline that we have developed to monitor animal populations for conservation purposes. Taking a multi-disciplinary approach to tackle this problem, we use freely available astronomical source detection software and the associated expertise of astronomers, to efficiently and reliably detect humans and animals in aerial thermal-infrared footage. Combining this astronomical detection software with existing machine learning algorithms into a single, automated, end-to-end pipeline, we test the software using aerial video footage taken in a controlled, field-like environment. We demonstrate that the pipeline works reliably and describe how it can be used to estimate the completeness of different observational datasets to objects of a given type as a function of height, observing conditions etc. - a crucial step in converting video footage to scientifically useful information such as the spatial distribution and density of different animal species. Finally, having demonstrated the potential utility of the system, we describe the steps we are taking to adapt the system for work in the field, in particular systematic monitoring of endangered species at National Parks around the world

Production of Multiple Brain-Like Ganglioside Species Is Dispensable for Fas-Induced Apoptosis of Lymphoid Cells

Activation of an acid sphingomyelinase (aSMase) leading to a biosynthesis of GD3 disialoganglioside has been associated with Fas-induced apoptosis of lymphoid cells. The present study was undertaken to clarify the role of this enzyme in the generation of gangliosides during apoptosis triggered by Fas ligation. The issue was addressed by using aSMase-deficient and aSMase-corrected cell lines derived from Niemann-Pick disease (NPD) patients. Fas cross-linking elicited a rapid production of large amounts of complex a- and b-series species of gangliosides with a pattern and a chromatographic behavior as single bands reminiscent of brain gangliosides. The gangliosides were synthesized within the first ten minutes and completely disappeared within thirty minutes after stimulation. Noteworthy is the observation that GD3 was not the only ganglioside produced. The production of gangliosides and the onset of apoptotic hallmarks occurred similarly in both aSMase-deficient and aSMase-corrected NPD lymphoid cells, indicating that aSMase activation is not accountable for ganglioside generation. Hampering ganglioside production by inhibiting the key enzyme glucosylceramide synthase did not abrogate the apoptotic process. In addition, GM3 synthase-deficient lymphoid cells underwent Fas-induced apoptosis, suggesting that gangliosides are unlikely to play an indispensable role in transducing Fas-induced apoptosis of lymphoid cells