Staff publications (SoE)

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Open Access
Improved depth recovery in consumer depth cameras via disparity space fusion within cross-spectral stereo
(British Machine Vision Association, 2014-09-01) Payen de La Garanderie, Gregoire; Breckon, Toby P.
We address the issue of improving depth coverage in consumer depth cameras based on the combined use of cross-spectral stereo and near infrared structured light sensing. Specifically we show that fusion of disparity over these modalities prior to subsequent optimization, within the disparity space image, facilitates the recovery of scene depth information in regions where structured light sensing alone fails. This joint approach, leveraging disparity information from both structured light and cross-spectral stereo, facilitates the recovery of global scene depth comprising both texture-less object depth, where stereo sensing commonly fails, and highly reflective object depth, where structured light active sensing commonly fails. The proposed solution is illustrated using dense gradient feature matching and is shown to outperform prior approaches that use late-stage fused cross-spectral stereo depth as a facet of improved sensing for consumer depth cameras.
Open Access
Fast model predictive control and its application to energy management of hybrid electric vehicles
(Intechopen, 2011-06-24) Fekri, Sajjad; Assadian, Francis
Modern day automotive engineers are required, among other objectives, to maximize fuel economy and to sustain a reasonably responsive car (i.e. maintain driveability) while still meeting increasingly stringent emission constraints mandated by the government. Towards this end, Hybrid Electric Vehicles (HEVs) have been introduced which typically combine two different sources of power, the traditional internal combustion engine (ICE) with one (or more) electric motors, mainly for optimising fuel efficiency and reducing Carbon Dioxide (CO2) and greenhouse gases (GHG) (Fuhs, 2008).
Open Access
A two-step optimisation method for dynamic weapon target assignment problem
(Intechopen, 2013-01-30) Leboucher, Cédric; Shin, Hyo-Sang; Siarry, Patrick; Chelouah, Rachid; Le Ménec, Stéphane; Tsourdos, Antonios
The weapon target assignment (WTA) problem has been designed to match the Command & Control (C2) requirement in military context, of which the goal is to find an allocation plan enabling to treat a specific scenario in assigning available weapons to oncoming targets. The WTA always get into situation weapons defending an area or assets from an enemy aiming to destroy it. Because of the uniqueness of each situation, this problem must be solved in real-time and evolve accordingly to the aerial/ground situation. By the past, the WTA was solved by an operator taking all the decisions, but because of the complexity of the modern warfare, the resolution of the WTA in using the power of computation is inevitable to make possible the resolution in real time of very complex scenarii involving different type of targets. Nowadays, in most of the C2 this process is designed in order to be as a support for a human operator and in helping him in the decision making process. The operator will give its final green light to proceed the intervention.
Open Access
Defect source location of a natural defect on a high speedrolling element bearing with Acoustic Emission
(PHM Society, 2011-09-25) Eftekharnejad, Babak; Addali, Abdulmajid; Mba, David
The application of Acoustic Emission (AE) technology for machine health monitoring is gaining ground as powerful tool for health diagnosis of rolling element bearings. The successful application of AE to life prognosis of bearings is very dependent on the ability of the technology to identify and locate a defect at its earliest stage. Determining source locations of AE signals originating in real time from materials under load is one of the major advantages of the technology. This paper presents results which highlight the ability of AE to locate naturally initiated defects on high-speed roller element bearing in-situ. To date such location has only be successfully demonstrated at rotational speeds of less than 100 rpm.
Open Access
On perspective errors in endoscopic PIV
(Elsevier, 2004-07-23) Reeves, Mark; Lawson, Nicholas J.
Results are presented from a single and dual lens endoscopic PIV imaging system with a view to application of PIV where optical access is restricted such as internal flows. The dual lens PIV images were processed using cross-correlation, a cubic mapping function and standard stereoscopic relationships. For the single lens system, the images were processed using cross-correlation and a quadratic distortion-mapping function. Results have shown the single lens system to have in-plane errors an order of magnitude greater than the stereoscopic dual lens endoscopic PIV system. These errors are generated by perspective effects. Use of the stereo arrangement is therefore recommended wherever quantitative 3D velocimetry data is acquired using an endoscopic system.
Open Access
Identification and quality assessment of beverages using a long period grating fibre-optic sensor modified with a mesoporous thin film
(Elsevier, 2014-07-23) Korposh, Sergiy; Selyanchyn, Roman; James, Stephen; Tatam, Ralph; Lee, Seung-Woo
In this study, an optical fibre long period grating (LPG) sensor functionalised with a mesoporous thin film was employed for the identification and quality assessment of beverages. The principle of the discrimination of beverages using an LPG sensor is based on the measurement of the change in refractive index of a sensitive film, induced by the binding of the chemical compounds present in the beverage. The sensitive film deposited onto the LPG consisted of poly(allylamine hydrochloride) (PAH) and silica nanospheres (SiO2 NPs) with diameters ranging from 40 nm to 50 nm. PAH imparts selectivity, while the SiO2 NPs endow the film with high porosity and enhanced sensitivity. In this study, five different types of beverages, red and white wines, brandy, nihonshyu (sake, a Japanese rice wine), and shochu (a Japanese distilled beverage), prepared via distillation and fermentation, were used to assess the capability of the sensor to identify the origin of the beverages. In addition, a selection of red wines was used to evaluate the use of the sensor in the assessment of the quality of beverages. The results obtained were benchmarked against those obtained using gas chromatography–mass spectrometry for the determination of volatile compounds contributing to the flavours of a set of red wines. Principal component analysis (PCA) was employed for data analysis. This approach enabled both quality assessment of beverages and identification of the methods and materials used for their preparation.
Open Access
FLAVIIR, An innovative university/industry research program for collaborative research and demonstration of UAV technologies
(ICAS, 2006-09-08) Fielding, J. P.; Smith, Howard
A major research programme into advanced technologies for Uninhabited Airborne Vehicles (UAVs) in June 2004. The £6.5M, five-year project represents a major investment in aerospace technology for BAE SYSTEMS and their partner, the Engineering and Physical Sciences Research Council (EPSRC). The focus of “FLAVIIR” is to develop technologies which support low cost (to acquire and operate) UAVs, together with the broader goal of improving the exploitation and hence impact of the research work completed through closer management of the research team. The project involves ten universities working together at two levels: inter-university collaboration within disciplines and interdisciplinary collaboration both within and across university boundaries. This aspect makes the project particularly challenging for Cranfield, as it is managing the complete project (with BAE Systems) and is to deliver the benefits of these joint activities. This work leads to the integration of the technologies into a sophisticated flying demonstrator UAV which is scheduled to fly in 2009. A particularly challenging requirement is that the vehicle should demonstrate an entire flight cycle, without the use of conventional flap-type control surfaces. The project now has more than 35 researchers working in subject areas ranging from novel aerodynamic techniques to develop control forces, novel flight control systems, to hybrid laser techniques to ‘write’ sensors and actuators directly onto carbon composite structures. The paper gives a description of the new technologies being developed, their integration into a number of demonstrations and the plans for their culmination in the Demon flying demonstrator vehicle, which will be based on the Eclipse Vehicle. The paper will also discuss the equally important issues of integrating, a multi-university/Industry research team.
Open Access
The environmental case for the high-speed train in the UK: examining the London–Manchester route
(Taylor and Francis, 2013-07-26) Miyoshi, Chikage; Givoni, Moshe
This article investigates the potential for environmental benefit from the introduction of the High Speed Train (HST) on the London–Manchester route in the UK, focusing on carbon dioxide (CO2) emissions. The lifecycle carbon emission of HST is assessed, and its sensitivity to demand changes is analyzed for several scenarios. Based on the UK Government demand assumptions, the analysis shows relatively limited potential for reduction in CO2 emissions. In 2033, overall CO2 reduction due to HST operation on the route is estimated at 100,000 tCO2 per annum, which is less than 0.1% of the total UK domestic transport emissions in 2007.
Open Access
System design for geosynchronous synthetic aperture radar missions
(Institute of Electrical and Electronics Engineers, 2014-06-12) Hobbs, Stephen; Mitchell, Cathryn; Forte, Biagio; Holley, Rachel; Snapir, Boris; Whittaker, Philip
Geosynchronous synthetic aperture radar (GEO SAR) has been studied for several decades but has not yet been implemented. This paper provides an overview of mission design, describing significant constraints (atmosphere, orbit, temporal stability of the surface and atmosphere, measurement physics, and radar performance) and then uses these to propose an approach to initial system design. The methodology encompasses all GEO SAR mission concepts proposed to date. Important classifications of missions are: 1) those that require atmospheric phase compensation to achieve their design spatial resolution; and 2) those that achieve full spatial resolution without phase compensation. Means of estimating the atmospheric phase screen are noted, including a novel measurement of the mean rate of change of the atmospheric phase delay, which GEO SAR enables. Candidate mission concepts are described. It seems likely that GEO SAR will be feasible in a wide range of situations, although extreme weather and unstable surfaces (e.g., water, tall vegetation) prevent 100% coverage. GEO SAR offers an exciting imaging capability that powerfully complements existing systems.
Open Access
Electronic tuning of misaligned coils in wireless power transfer systems
(IEEE Institute of Electrical and Electronics, 2014-11-01T00:00:00Z) Aldhaher, Samer; Luk, Patrick Chi-Kwong; Whidborne, James F.
The misalignment and displacement of inductively coupled coils in a wireless power transfer system (WPT) can degrade the power efﬁciency and limit the amount of power that can be transferred. Coil misalignment leads the primary coil driver to operate in an untuned state which causes non-optimum switching operation and results in an increase in switching losses. This paper presents a novel method to electronically tune a Class E inverter used as a primary coil driver in an inductive WPT system to minimize the detrimental effects of misalignment between the inductively coupled coils which may occur during operation. The tuning method uses current controlled inductors (saturable reactors) and a variable switching frequency to achieve optimum switching conditions regardless of the misalignment. Mathematical analysis is performed on a Class E inverter based on an improved model of a resonant inductive link. Experimental results are presented to conﬁrm the analysis approach and the suitability of the proposed tuning method.
Open Access
A production system variable connectance model
(Cranfield Institute of technology, 1984-02) Burbidge, John L.
Open Access
Effect of laser processing parameters on the formation of intermetallic compounds in Fe-Al dissimilar welding
(Springer Intrnational, 2014-09-01T00:00:00Z) Meco, Sonia; Ganguly, Supriyo; Williams, Stewart W.; McPherson, Norman
Fusion welding of steel to aluminum is difficult due to formation of different types of Fe-Al intermetallics (IMs). In this work, 2mm-thick steel was joined to 6mm aluminum in overlap configuration using a 8kW CW fiber laser. A defocused laser beam was used to control the energy input and allow melting of the aluminum alone and form the bond by wetting of the steel substrate. Experimentally, the process energy was varied by changing the power density (PD) and interaction time separately to understand the influence of each of these parameters on the IM formation. It was observed that the IM formation is a complex function of PD and interaction time. It was also found that the mechanical strength of such joint could not be simply correlated to the IM layer thickness but also depends on the area of wetting of the steel substrate by molten aluminum. In order to form a viable joint, PD needs to be over a threshold value where although IM growth will increase, the strength will be better due to increased wetting. Any increase in interaction time, with PD over the threshold, will have negative effect on the bond strength.
Open Access
Dielectric and tunability properties of the Pb(Mg1/3Nb2/3)1-xZrxO3 ceramics
(Elsevier Science B.V., Amsterdam., 2013-02-05T00:00:00Z) Peng, Biaolin; Fan, Huiqing; Li, Q; Zhang, Qi
Pure perovskite Pb(Mg1/3Nb2/3)0.8(Sc1/2Nb1/2)0.2O3 ceramics was prepared via a modified “columbite-type” method. The 1:1 B-site ordered structure of Pb(Sc1/2Nb1/2)O3 was detected by XRD and TEM. The dielectric relaxor behavior was described by a Lorentz relation. The dielectric tunability properties were investigated at 300K and 10 kHz. The results show that the ceramics possesses high dielectric tunability (~ 75% at 30 kV/cm), low dielectric loss (~ 0.003) and high figure of merit (~ 250), indicating that it is a promising tunable material. The high dielectric nonlinear behavior was illustrated by employing the Landau-Ginsberg-Devonshire thermodynamic theory and a multipolarization mechanism model. The results indicate that the high non-linearity is related to the contributions of the “extrinsic” polarizations such as the polar nanoregions and nanometer domain wall motions, etc., in addition to the contribution of the “intrinsic” lattice phonon polarization.
Open Access
A comparison of polymer film and glass collectors for concentrating solar power
(Elsevier, 2014-06-02T00:00:00Z) Sansom, Christopher L.; Comley, Paul; Bhattacharyya, Debabrata; Macerol, Nastja
This paper describes work to compare the optical properties and surface texture of glass and polymer film collectors. We also present the results of experiments designed to simulate collector cleaning processes (both contact and non-contact), and the degradation of glass and polymer reflecting surfaces owing to sand and dust abrasion. Finally we present initial results on the applicability of anti-soiling and self-cleaning coatings on glass and polymer film collector surfaces. Measurements, which include specular and hemispherical reflectance, surface roughness, and electron microscopy, indicate the excellent performance of currently available polymer film in terms of its optical performance and robustness in comparison with traditional glass collectors in CSP applications.
Open Access
Long period grating based toluene sensor for use with water contamination
(Elsevier Science B.V., Amsterdam., 2014-11-01T00:00:00Z) Partridge, Matthew; Wong, Rebecca; James, Stephen W.; Davis, Frank; Higson, Seamus P. J.; Tatam, Ralph P.
A demonstration of the use of a calix[4]resorcinarene coated optical fibre long period grating sensor for the detection of toluene in water is presented. Monitoring water quality both for domestic use and around industrial sites is critical to the preservation of clean water provision. Here we show that, by using a fibre optic based sensor system, water quality monitoring can be carried out without the requirement for water sampling or pre-concentration. The results presented demonstrate that this proof-of-concept sensor is capable of sensing ∼100ppm concentrations of toluene with semi-selectivity and low (<10ppm) variation.
Open Access
Formaldehyde sensor using non-dispersive UV spectroscopy at 340nm
(International Society for Optical Engineering; 1999, 2014-05-22T00:00:00Z) Davenport, John; Hodgkinson, Jane; Saffell, John R.; Tatam, Ralph P.; Berghmans, F.; Mignani, A. G.; De Moor, P.
Formaldehyde is a volatile organic compound that exists as a gas at room temperature. It is hazardous to human health causing irritation of the eyes, nose and throat, headaches, limited pulmonary function and is a potential human carcinogen. Sources include incomplete combustion, numerous modern building materials and vehicle fumes. Here we describe a simple method for detecting formaldehyde using low resolution non-dispersive UV absorption spectroscopy for the first time. A two channel system has been developed, making use of a strong absorption peak at 339nm and a neighbouring region of negligible absorption at 336nm as a reference. Using a modulated UV LED as a light source and narrowband filters to select the desired spectral bands, a simple detection system was constructed that was specifically targeted at formaldehyde. A minimum detectable absorbance of 4.5 × 10-5 AU was estimated (as ΔI/I0), corresponding to a limit of detection of approximately 6.6 ppm for a 195mm gas cell, with a response time of 20s. However, thermally-induced drift in the LED spectral output caused this to deteriorate over longer time periods to around 30 ppm or 2 × 10-4 AU
Open Access
The effect of volatilisation of refractory metal oxides on the cyclic oxidation of Ni-base superalloys
(Springer Science Business Media, 2014-04-01T00:00:00Z) Brewster, Gyaneshwara; Edmonds, I. M.; Gray, Simon
The role of refractory metals on the bare oxidation behaviour of a range of compositionally complex single crystal Ni-base superalloys has been investigated using a range of techniques. It has been shown that this series of fourth generation alloys were borderline alumina formers at 1,100 °C, and their cyclic oxidation performance was detrimentally affected by increased levels of Mo and Co. In addition, there was strong evidence that Re, Ru and Mo were lost through the process of cyclic oxidation, which supports the hypothesis that these elemental additions were lost through volatilisation/sublimation, contributing to their poor cyclic oxidation performance.
Open Access
Direct replacement of antibodies with molecularly imprinted polymer (MIP) nanoparticles in ELISA - development of a novel assay for vancomycin
(ACS American Chemical Society, 2013-09-03T00:00:00Z) Chianella, Iva; Guerreiro, Antonio R.; Moczko, Ewa; Caygill, J. S.; Piletska, Elena V.; Perez De Vargas Sansalvador, Isabel M.; Whitcombe, Michael J.; Piletsky, Sergey A.
A simple and straightforward technique for coating microplate wells with molecularly imprinted polymer nanoparticles (nanoMIPs) to develop ELISA type assays is presented here for the first time. NanoMIPs were synthesized by a solid phase approach with immobilized vancomycin (template) and characterized using Biacore 3000, dynamic light scattering and electron microscopy. Immobilization, blocking and washing conditions were optimized in microplate format. The detection of vancomycin was achieved in competitive binding experiments with a HRP-vancomycin conjugate. The assay was capable of measuring vancomycin in buffer and in blood plasma within the range 0.001-70 nM with a detection limit of 0.0025 nM (2.5 pM). The sensitivity of the assay was three orders of magnitude better than a previously described ELISA based on antibodies. In these experiments nanoMIPs have shown high affinity and minimal interference from blood plasma components. Immobilized nanoMIPs were stored for 1 month at room temperature without any detrimental effects to their binding properties. The high affinity of nanoMIPs and the lack of a requirement for cold chain logistics make them an attractive alternative to traditional antibodies used in ELISA
Open Access
Passive OCT probe head for 3D duct inspection
(Iop Publishing Ltd, 2013-07-24T00:00:00Z) Ford, Helen D.; Tatam, Ralph P.
A passive, endoscopic optical coherence tomography (OCT) probe has been demonstrated, incorporating an imaging fibre bundle and 45° conical mirror, and with no electromechanical components at the probe tip. Circular scanning, of the beam projected onto the proximal face of the imaging bundle, produces a corresponding circular scan at the distal end of the bundle. The beam is turned through 90° by the conical mirror and converted into a radially-scanned sample beam, permitting circumferential OCT scanning in quasi-cylindrical ducts. OCT images, displayed as polar plots and as 3D reconstructions, are presented, showing the internal profile of a metallic test sample containing a 660µm step in the internal wall. Results have been acquired using two methods: one that makes use of multiple beam-circle diameters, and a mechanical 'pull-back' technique. The effects of the convex surface of the conical mirror on spatial resolution are discussed, with suggested working distances given for different application regimes.
Open Access
Total Lagrangian SPH modelling of necking and fracture in electromagnetically driven rings
(Springer Science Business Media, 2013-03-31T00:00:00Z) De Vuyst, Tom; Vignjevic, Rade
This paper describes research on the prediction of necking and failure in metals at very high strain rates. The model developed in this paper uses a total Lagrangian SPH formulation with a normalised kernel. The detailed data from electromagnetically driven ring experiments by Zhang and Ravi-Chandar (Int J Fract 142:183-217, 2006) is used to evaluate the accuracy of the model predictions. In order to correctly model fracture in the total Lagrangian SPH formulation a visibility criterion based on a truncated cone has been implemented to remove particles obscured by a failed particle. A Johnson-Cook plasticity model is used in combination with a Lemaitredamage model to describe the plastic deformation and fracture of the rings. The effect of Joule heating due to the current induced in the ring is taken into account in the constitutive model. The acceleration due to the ring currents was implemented in the SPH code as a body force. The results demonstrate that this type of model is capable of predicting the number of fragments as well as the time of fracture. In agreement with experimental data, the model also predicts arrested necks and bending in the fragments.