Browsing by Author "James, Stephen"
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Item Open Access All-optical switching based on optical fibre long period gratings modified bacteriorhodopsin(Elsevier, 2017-11-24) Korposh, Sergiy; James, Stephen; Partridge, Matthew; Sichka, M; Tatam, Ralph P.All-optical switching using an optical fibre long-period gating (LPG) modified with bacteriorhodopsin (bR) is demonstrated. The switching process is based on the photo-induced RI change of bR, which in turn changes the phase matching conditions of the mode coupling by the LPG, leading to modulation of the propagating light. The effect was studied with an LPG immersed into a bR solution and with LPGs coated with the bR films, deposited onto the LPGs using the layer-by-layer electrostatic self-assembly (LbL) method. The dependence of the all-optical switching efficiency upon the concentration of the bR solution and on the grating period of the LPG was also studied. In addition, an in-fibre Mach-Zehnder interferometer (MZI) composed of a cascaded LPG pair separated by 30 mm and modified with bR was used to enhance the wavelength range of all-optical switching. The switching wavelength is determined by the grating period of the LPG. Switching efficiencies of 16% and 35% were observed when an LPG and an MZI were immersed into bR solutions, respectively. The switching time for devices coated with bR-films was within 1 s, 10 times faster than that observed for devices immersed into bR solution.Item Open Access An ammonia sensor based on Lossy Mode Resonances on a tapered optical fibre coated with porphyrin-incorporated titanium dioxide(Cranfield University, 2016-11-28 09:12) Tiwari, Divya; Mullaney, Kevin; James, Stephen; Tatam, RalphData presented in: An ammonia sensor based on Lossy Mode Resonances on a tapered optical fibre coated with porphyrin-incorporated titanium dioxide, Tiwari et al Sensors and Actuators B 2016 - http://dx.doi.org/10.1016/j.snb.2016.11.092 Figure3.xlsx - The transmission spectrum obtained in air and water from a typical 40 µm non-adiabatic (a), a 17 µm non-adiabatic (b), a 40 µm adiabatic (c) and a 17 µm adiabatic (d) tapered optical fibre. Figure 4.zip - transmission spectra of a non-adiabatic tapered optical fibre of waist diameter 17 microns with time and thus increasing thickness of the TMPyP-TiO2 coating. Figure 5_6_7.zip - transmission spectrum of an adiabatic tapered optical fibre of waist diameter 17 microns with time and thus increasing thickness of the TMPyP-TiO2 coating. Figure 8 and 9.zip transmission spectra when an adiabatic tapered optical fibre of diameter 17 microns was immersed in differing concentrations of ammoniaItem Open Access Application of fibre optic sensing systems to measure rotor blade structural dynamics(Elsevier, 2021-03-09) Weber, Simone; Kissinger, Thomas; Chehura, Edmond; Staines, Stephen; Barrington, James; Mullaney, Kevin; Fragonara, Luca Zanotti; Petrunin, Ivan; James, Stephen; Lone, Mudassir; Tatam, Ralph P.This paper compares two fibre optic sensing techniques for vibration characterisation: (a) optical fibre Bragg grating (FBG) strain gauges and (b) a novel direct fibre optic shape sensing (DFOSS) approach based on differential interferometric strain measurements between multiple fibres within the same fibre arrangement. Operational mode shapes and frequency measurements of an Airbus Helicopters H135 bearingless main rotor blade (5.1 m radius) were acquired during a series of ground vibration tests undertaken in a controlled laboratory environment. Data recorded by the fibre optic instrumentation systems were validated using commercially available accelerometers and compared against a baseline finite element model. Both fibre optic sensing systems proved capable of identifying the natural frequencies of the blade in the frequency range of interest (0–100 Hz). The data from the FBG sensors exhibited a dependency on their position relative to the neutral axes of the blade, which meant that full characterisation of the flapping and lagging modes required careful consideration of sensor location in the chordwise direction. The DFOSS system was able to identify all structural dynamics, despite being located on the neutral axis in the lagging direction, due to its sensitivity to angle changes, rather than strain, and its biaxial measurement capability. The DFOSS system also allowed the operational mode shapes of the blade to be determined directly, without the requirement for strain transfer from the blade to the sensor and without the requirement for a model of the underlying structure. The accuracy of obtained natural frequencies and operational mode shapes is assessed, demonstrating the potential of the use of both fibre optic sensing systems for determining blade structural dynamics.Item Open Access Application of fibre optic sensing systems to measure rotor blade structural dynamics - underlying data(Cranfield University, 2021-03-12 09:17) James, Stephen; Kissinger, Thomas; Tatam, Ralph; Barrington, James; Chehura, Edmon; Weber, Simone; Mullaney, Kevin; Zanotti Fragonara, Luca; Petrunin, Ivan; Staines, StephenRefer to the paper for full details. Fig9a.csv: Comparison of the Power Spectral Density (PSD) of data recorded by the direct optical fibre shape sensing system, an optical fibre Bragg grating strain sensor and a 1D accelerometer with finite element modeling predictions, measured on the top surface of an Airbus Helicopters H135 bearingless main rotor blade on the quarter chord line at approximately 40% rotor radius. Fig9b.csv: Comparison of the Power Spectral Density (PSD) of data recorded by the direct optical fibre shape sensing system, an optical fibre Bragg grating strain sensor and a 1D accelerometer with finite element modeling predictions, measured on the top surface of an Airbus Helicopters H135 bearingless main rotor blade on the quarter chord line at approximately 60% rotor radius. Fig10_FBG_top.csv: Power Spectral Density (PSD) of the 7th fibre Bragg grating strain (FBG) sensor (FBG7) in the three FBG arrays bonded to the top surface of the Airbus Helicopters H135 bearingless main rotor blade, located at approximately 60% rotor radius. Fig10_FBG_bottom.csv: Power Spectral Density (PSD) of the 7th fibre Bragg grating strain sensor (FBG7) in the three FBG arrays bonded to the bottom surface of the Airbus Helicopters H135 bearingless main rotor blade, located at approximately 60% rotor radius. Fig11.csv: Time series of raw data of 3F frequency input collected at approximately 60% rotor radius for the accelerometer, fibre Bragg grating strain sensor and direct optical fibre shape sensor (vertical direction). Fig12.csv: Comparison of Power Spectral Density (PSD) for the 3F mode measured at approximately 60% rotor radius by the accelerometer, fibre Bragg grating strain sensor and direct optical fibre shape sensor (vertical direction). Fig14.csv: Mode shapes measured using the direct optical fibre shape sensor Fig15.cvs: Comparison of normalised displacement mode shapes measured using a 1D accelerometer, the direct optical fibre shape sensor with the finite element model prediction Fig16.csv: Normalised angle measurements performed by the direct optical fibre shape sensor with the ouput from the FE model for Mode 5F Fig17.csv:Comparison of normalised strain mode shapes determined by the FBG strain sensors and the output from the FE model.Item Open Access Bladesense – a novel approach for measuring dynamic helicopter rotor blade deformation(European Rotorcraft Forum, 2018-12-31) Weber, Simone; Southgate, Dominic; Mullaney, Kevin; James, Stephen; Rutherford, Robert; Sharma, Anuj; Lone, Mudassir; Kissinger, Thomas; Chehura, Edmond; Staines, Stephen; Pekmezci, Huseyin; Fragonara, Luca Zanotti; Petrunin, Ivan; Williams, Dan; Moulitsas, Irene; Cooke, Alastair; Rosales, Waldo; Tatam, Ralph P.; Morrish, Peter; Fairhurst, Mark; Atack, Richard; Bailey, Gordon; Morley, StuartTechnologies that allow accurate measurement of rotorblade dynamics can impact almost all areas of the rotorcraft sector; ranging from maintenance all the way to blade design. The BladeSense project initiated in 2016 aims to take a step in developing and demonstrating such a capability using novel fibre optic sensors that allow direct shape measurement. In this article the authors summarise key project activities in modelling and simulation, instrumentation development and ground testing. The engineering approach and associated challenges and achievements in each of these disciplines are discussed albeit briefly. This ranges from the use of computational aerodynamics and structural modelling to predict blade dynamics to the development of direct fibre optic shape sensing that allows measurements above 1kHz over numerous positions on the blade. Moreover, the development of the prototype onboard system that overcomes the challenge of transferring data between the rotating main rotor to the fixed fuselage frames is also discussed.Item Open Access Data for: The use of range-resolved interferometry for multi-parameter sensing in a wind tunnel(Cranfield University, 2023-12-12 14:59) Barrington, James; James, Stephen; Kissinger, Thomas; Staines, Stephen; Alcusa Saez, Erica; Lawson, Nicholas; Tatam, Ralph; Prince, SimonEach data set relates to the data displayed in Figure 2 of the conference paper. The 1st column in each file outlines the data type and unit.Item Open Access Data supporting "Optical Fibre Pressure Sensing Using a Frequency Modulated Laser-Based Signal Processing Technique"(Cranfield University, 2023-04-21 12:36) Barrington, James; James, Stephen; Kissinger, Thomas; Staines, Stephen; Prince, Simon; Alcusa Saez, Erica; Lawson, Nicholas; Tatam, RalphEach file contains the relevant data to the figure as stated in its name. Column headers within the file outline the variable and its associated unit. The authors, where possible, have tried to keep the data in its rawest, useable form in order to provide the greatest flexibility for future manipulation. All data files are formatted as csv for accessibility.Item Open Access Data supporting: 'Electromagnetic Field Controlled Domain Wall Displacement for Induced Strain Tailoring in BaTiO3-Epoxy Nanocomposite'(Cranfield University, 2022-08-31 13:30) Yazdani Nezhad, Hamed; Li, Danning; Barrington, James; James, Stephen; Ayre, David; Sloma, Marcin; Lin, Meng-FangThis dataset is comprised of 4 files: 100W_strains, 100W_temperature, 440W_strains, and 440W_temperature.Failure in an epoxy polymer composite material is prone to initiate by the coalescence of microcracks in its polymer matrix. As such, matrix toughening via addition of a second phase as rigid or/and rubber nano/micro-particles is one of the most popular approaches to improve the fracture toughness across multiple scales in a polymer composite, which dissipates fracture energy via deformation mechanisms and microcracks arrest. Few studies have focused on tailorable and variable toughening, so-called ‘active toughening’, mainly suggesting thermally induced strains which offer slow and irreversible toughening due to polymer’s poor thermal conductivity. The research presented in the current article has developed an instantaneous, reversible active toughening composite based upon contact-less introduction of a microscopic compressive extrinsic strain field via remote electromagnetic radiation. Quantification of the extrinsic strain evolving in the composite with the microwave energy has been conducted using in-situ realtime fibre optic sensing. A theoretical constitutive equation correlating the exposure energy to micro-strains has been developed, with its solution validating the experimental data and describing their underlying physics. The research has utilised functionalised dielectric ferroelectric nanomaterials, barium titanate (BaTiO3), as a second phase dispersed in an epoxy matrix, able to introduce microscopic electro-strains to their surrounding rigid epoxy subjected to an external electric field (microwaves, herein), as result of their domain walls dipole displacements. Epoxy Araldite LY1564, a diglycidyl ether of bisphenol A (DGEBA) associated with the curing agent Aradur 3487 were embedded with the BaTiO3 nanoparticles. The silane coupling agent for the nanoparticles’ surface functionalisation was 3-glycidoxypropyl trimethoxysilane (3-GPS). Hydrogen peroxide (H2O2, 30%) and acetic acid (C2H4O2, 99.9%) used as functionalisation aids, and the ethanol (C2H6O, 99.9%) used for BaTiO3 dispersion. Firstly, the crystal microstructure of the functionalised nanoparticles and the thermal and dielectric properties of the achieved epoxy composite materials have been characterised. It has been observed that the addition of the dielectric nanoparticles has a slight impact on the curing extent of the epoxy. Secondly, the surface-bonded fibre bragg grating (FBG) sensors have been employed to investigate the real-time variation of strain and temperature in the epoxy composites exposed to microwaves at 2.45 GHz and at different exposure energy. The strains developed due to the in-situ exposure at composite, adhesive and their holding fixture material were evaluated using the FBG. The domain wall induced extrinsic strains were distinguished from the thermally induced strains, and found that the increasing exposure energy has an instantaneously increasing effect on the development of compressive strains. Post-exposure Raman spectra showed no residual field in the composite indicating no remnant strain field examined under microwave powersItem Open Access Data supporting: 'Fibre-optic measurement of strain and shape on a helicopter rotor blade during a ground run: data for the measurement of shape'(Cranfield University, 2022-09-01 15:50) Kissinger, Thomas; James, Stephen; Weber, Simone; Mullaney, Kevin; Chehura, Edmon; Barrington, James; Staines, Stephen; Tatam, RalphFSI_Phase_Data_Shape_CORD.csv contains the raw phase data from the three Fibre Segment interferometry array installed on the Direct Optical Fibre Shape Sensing Rod described in the paper: "Fibre-optic measurement of strain and shape on a helicopter rotor blade during a ground run - part 2: measurement of shape", Smart Materials and Structure, online 25 May 2022. Shape_Data_Vertical_CORD.csv contains the processed shape data in the vertical (flapping) direction, for the T&B2 ground run. Note that the position measurements are relative to the first FSI reflector on the rod, not to the centre of rotation of the blade. Shape_Data_Horizontal_CORD.csv contains the processed shape data n the horizontal (lagging) direction, for the T&B2 ground run. Note that the position measurements are relative to the first FSI reflector on the rod, not to the centre of rotation of the blade.Item Open Access Data supporting: 'Fibre-optic measurement of strain and shape on a helicopter rotor blade during a ground run: data for the measurement of strain'(Cranfield University, 2022-09-01 15:49) James, Stephen; Kissinger, Thomas; Weber, Simone; Mullaney, Kevin; Chehura, Edmon; Barrington, James; Tatam, RalphFBG_Data_CORD.csv contains the raw wavelength data from the 10 FBGs (G1-G10) recorded during the ground run detailed within the paper "Fibre-optic measurement of strain and shape on a helicopter rotor blade during a ground run - part 1: measurement of strain", James et al. Smart Materials and Structures, available online, May 2022. The unit of the "Time" column is seconds, while the units of columns G1-G10 are nanometers. FSI_Data_CORD.csv contains the raw phase data obtained from the interferometers formed between the reflectors (R1-R10,) and the cleaved end of the optical fibre, recorded during the ground run detailed within the paper The unit of the "Time" column is seconds, while the units of columns R1-R10 are radians.Item Open Access The effect of UV irradiation duty cycle on the 2nd harmonic coupling efficiency in optical fiber long period gratings(Elsevier, 2018-08-10) Barrington, James; Partridge, Matthew; James, Stephen; Tatam, Ralph P.Long period gratings (LPGs) as a sensing platform have the potential for multi-parameter measurement through the utilization of 2nd order coupling resonance bands. Although the current literature has produced LPGs with 2nd order resonance bands, the fabrication parameters required to generate these features have not been elucidated. Here, using UV irradiation via the point-by-point method, it is shown that by varying the duty cycle it is possible to fabricate LPGs that exhibit 2nd, 3rd, and 4th order coupling resonance bands. Fabrication of LPGs with a 25% or 75% duty cycle produces distinct 2nd order resonance bands, which are not observed when a 50% duty cycle is adopted.Item Open Access Electromagnetic field controlled domain wall displacement for induced strain tailoring in BaTiO3-epoxy nanocomposite(Nature, 2022-05-07) Li, Danning; Barrington, James; James, Stephen; Ayre, David; Sloma, Marcin; Lin, Meng-Fang; Yazdani Nezhad, HamedFailure in an epoxy polymer composite material is prone to initiate by the coalescence of microcracks in its polymer matrix. As such, matrix toughening via addition of a second phase as rigid or/and rubber nano/micro-particles is one of the most popular approaches to improve the fracture toughness across multiple scales in a polymer composite, which dissipates fracture energy via deformation mechanisms and microcracks arrest. Few studies have focused on tailorable and variable toughening, so-called ‘active toughening’, mainly suggesting thermally induced strains which offer slow and irreversible toughening due to polymer’s poor thermal conductivity. The research presented in the current article has developed an instantaneous, reversible extrinsic strain field via remote electromagnetic radiation. Quantification of the extrinsic strain evolving in the composite with the microwave energy has been conducted using in-situ real-time fibre optic sensing. A theoretical constitutive equation correlating the exposure energy to micro-strains has been developed, with its solution validating the experimental data and describing their underlying physics. The research has utilised functionalised dielectric ferroelectric nanomaterials, barium titanate (BaTiO3), as a second phase dispersed in an epoxy matrix, able to introduce microscopic electro-strains to their surrounding rigid epoxy subjected to an external electric field (microwaves, herein), as result of their domain walls dipole displacements. Epoxy Araldite LY1564, a diglycidyl ether of bisphenol A associated with the curing agent Aradur 3487 were embedded with the BaTiO3 nanoparticles. The silane coupling agent for the nanoparticles’ surface functionalisation was 3-glycidoxypropyl trimethoxysilane (3-GPS). Hydrogen peroxide (H2O2, 30%) and acetic acid (C2H4O2, 99.9%) used as functionalisation aids, and the ethanol (C2H6O, 99.9%) used for BaTiO3 dispersion. Firstly, the crystal microstructure of the functionalised nanoparticles and the thermal and dielectric properties of the achieved epoxy composite materials have been characterised. It has been observed that the addition of the dielectric nanoparticles has a slight impact on the curing extent of the epoxy. Secondly, the surface-bonded fibre Bragg grating (FBG) sensors have been employed to investigate the real-time variation of strain and temperature in the epoxy composites exposed to microwaves at 2.45 GHz and at different exposure energy. The strains developed due to the in-situ exposure at composite, adhesive and their holding fixture material were evaluated using the FBG. The domain wall induced extrinsic strains were distinguished from the thermally induced strains, and found that the increasing exposure energy has an instantaneously increasing effect on the development of such strains. Post-exposure Raman spectra showed no residual field in the composite indicating no remnant strain field examined under microwave powers < 1000 W, thus suggesting a reversible strain introduction mechanism, i.e. the composite retaining its nominal properties post exposure. The dielectric composite development and quantifications presented in this article proposes a novel active toughening technology for high-performance composite applications in numerous sectors.Item Open Access Fabrication of Optical Fibre Tapers(Cranfield University, 2017-05-19 08:47) Mullaney, K; James, Stephen; Tatam, RalphData concerning the fabrication of tapered optical fibres. Presented in Proc. SPIE 10323, 10323D. channelled_spectrum_development.zip - Evolution of channeled spectrum during tapering of SMF 28 optical fiber, using a CO2 laser as the heat source. OFS_2017_TAPER_FIGURE2.xlsx - The spectral response of a Vosskuhler NIR-300P NIR camera and the Planckian black body radiation curves (dashed lines) for a range of temperatures near the melting point of silica optical fibres. OFS_2017_TAPER_FIGURE4.xlsx - The strain measured bya fibre Bragg gratings and laser power used during the fabrication of a taper.Item Open Access FFT of square wave generation script(Cranfield University, 2018-01-29 08:55) Barrington, James; James, StephenPython 2.7 script used to create a discrete FFT of a square wave associated with our paper 'The effect of UV irradiation duty cycle on the transmission spectra of optical fiber long period gratings'Item Open Access High sensitivity pressure measurement using optical fibre sensors mounted on a composite diaphragm(Cranfield University, 2021-01-21 17:44) James, Stephen; Aime, Laura; Kissinger, Thomas; Chehura, Edmon; Tatam, RalphData underlying the work presented in the paper "High sensitivity pressure measurement using optical fibre sensors mounted on a composite diaphragm", published in Optics Express, 2020. Each zip file contains the data and a text file describing the contents. Full details are provided in the paperItem Open Access Highly sensitive and selective biosensor based on graphene oxide coated long period grating(SPIE, 2017-02-28) Partridge, Matthew; James, Stephen; Shaikh, M. S.; Liu, Chen; Zhu, W. D.; Chena, X.We propose an optical fiber immunosensor based on graphene oxide coated dual-peak long period grating (GO-dLPG), in which GO-IgG linking layer is used for rapid immunoassays. The binding interaction between antibody and antigen produced a detectable optical signal in terms of grating resonant wavelength shift, which was proportional to the analyte concentration. By deposition of GO overlay, the bulk RI sensitivity of dLPG was enhanced around 150%. The GO-coated dLPG was biofunctionalized by the immobilization of IgG to generate the biosensor. The IgG-bound GO-dLPG was used to detect the anti-IgG and anti-PSA, respectively, demonstrating high sensitivity and selectivity. The GO-dLPG biosensor can be further developed as a biosensing platform with advantages of label-free, real-time and low limit of detection.Item 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-WooIn 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.Item Open Access IEEE sensors 2016 poster(Cranfield University, 2016-10-21 15:18) Barrington, James; James, Stephen; Tatam, Ralph; Partridge, MatthewConference poster for IEEE sensors 2016 conference. Data can be found using the referenced URL.Item Open Access Interferometric robot joint angle measurement: data(Cranfield University, 2024-01-08 14:55) Naga Narayanan Ayyappan Pillai Rajeshwari, Sivaji; Charrett, Tom; Kissinger, Thomas; Barrington, James; James, Stephen; Tatam, RalphTime series of angle measurement performed on 3 joints of a robotic arm instrumented with an array of optical fibre based angle sensors, exploiting fibre segment interferometry, Data presetned and analysed in: A fibre optic angle sensing tape for applications in robotics and automationItem Open Access Long-period grating fiber-optic sensors exploiting molecularly imprinted TiO2 nanothin films with photocatalytic self-cleaning ability(Springer, 2020-11-17) Wang, Tao; Korposh, Sergiy; James, Stephen; Lee, Seung-WooHighly sensitive and selective long-period grating (LPG) fiber-optic sensors modified with molecularly imprinted TiO2 nanothin films were fabricated. The films were deposited onto the surface of the optical fiber via liquid-phase deposition (LPD), using tetrakis(N-methylpyridinium-4-yl)porphyrin (TMPyP) as a template. Three LPG resonance bands were monitored during film deposition, which was of duration 4.5 h. Prior to template removal, heat treatment at 60 °C under high-humidity conditions led to an increase in refractive index of the TiO2 film, evidenced by changes in the central wavelengths of the attenuation bands. After template removal using HCl solution (0.01 M), the TMPyP-imprinted film-modified LPG sensor showed higher sensitivity to the template molecule than to structurally related guest molecules. This was measured at the 1st and 2nd resonance bands, with wavelengths ranging from 690 to 738 nm and 815 to 905 nm, respectively. No selective binding of the template was observed with a non-imprinted TiO2 film prepared in the same manner. Furthermore, the heat-treated imprinted films exhibited a substantial enhancement of photocatalytic activity for template irradiation. In particular, the self-cleaning property of the imprinted film-modified LPG sensor under ultraviolet irradiation led to highly efficient and selective binding to the template. The mechanism of the interaction between the template and the TiO2 matrix was investigated by UV–vis and Fourier-transform infrared (FTIR) spectroscopies. Additionally, morphological studies using scanning electron microscopy (SEM) were conducted.