25 results on '"Gangadhara, B."'
Search Results
2. Novel Response Surface Technique for Composite Structure Localization Using Variable Acoustic Emission Velocity
- Author
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Binayak Bhandari, Phyo Thu Maung, and Gangadhara B. Prusty
- Subjects
acoustic emission ,composite laminates ,localization ,least-square method ,response surface ,velocity attenuation ,Chemical technology ,TP1-1185 - Abstract
The time difference of arrival (TDOA) method has traditionally proven effective for locating acoustic emission (AE) sources and detecting structural defects. Nevertheless, its applicability is constrained when applied to anisotropic materials, particularly in the context of fiber-reinforced composite structures. In response, this paper introduces a novel COmposite LOcalization using Response Surface (COLORS) algorithm based on a two-step approach for precise AE source localization suitable for laminated composite structures. Leveraging a response surface developed from critical parameters, including AE velocity profiles, attenuation rates, distances, and orientations, the proposed method offers precise AE source predictions. The incorporation of updated velocity data into the algorithm yields superior localization accuracy compared to the conventional TDOA approach relying on the theoretical AE propagation velocity. The mean absolute error (MAE) for COLORS and TDOA were found to be 6.97 mm and 8.69 mm, respectively. Similarly, the root mean square error (RMSE) for COLORS and TODA methods were found to be 9.24 mm and 12.06 mm, respectively, indicating better performance of the COLORS algorithm in the context of source location accuracy. The finding underscores the significance of AE signal attenuation in minimizing AE wave velocity discrepancies and enhancing AE localization precision. The outcome of this investigation represents a substantial advancement in AE localization within laminated composite structures, holding potential implications for improved damage detection and structural health monitoring of composite structures.
- Published
- 2024
- Full Text
- View/download PDF
3. Fibre-metal laminate structures: High-velocity impact, penetration, and blast loading – A review
- Author
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Serubibi, Arcade, Hazell, Paul J., Escobedo, Juan Pablo, Wang, Hongxu, Oromiehie, Ebrahim, Prusty, Gangadhara B., Phillips, Andrew W., and St John, Nigel A.
- Published
- 2023
- Full Text
- View/download PDF
4. Novel Response Surface Technique for Composite Structure Localization Using Variable Acoustic Emission Velocity
- Author
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Bhandari, Binayak, primary, Maung, Phyo Thu, additional, and Prusty, Gangadhara B., additional
- Published
- 2024
- Full Text
- View/download PDF
5. Post-gel polymerisation shrinkage profiling of polymer biomaterials using a chirped fibre Bragg grating
- Author
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Ginu Rajan, Alex Wong, Paul Farrar, and Gangadhara B. Prusty
- Subjects
Medicine ,Science - Abstract
Abstract A strain profile measurement technique using a chirped fibre Bragg grating (CFBG) sensor by implementing an integration of differences (IOD) method is reported in this paper. Using the IOD method the spatial distribution of strain along the length of the CFBG is extracted from its power reflectance spectra. As a proof of concept demonstration, the developed technique is applied to measure the polymerisation shrinkage strain profile of a photo-cured polymer dental composite which exhibits a non-uniform strain distribution attributed to the curing lamp characteristics. The result from the CFBG technique is compared with that of an FBG array embedded in the dental composite and is correlated with the degree of conversion of the material which also depends on the curing lamp intensity distribution. This technology will have significant impact and applications in a range of medical, materials and engineering areas where strain or temperature gradient profile measurement is required in smaller scales.
- Published
- 2021
- Full Text
- View/download PDF
6. Analysis of AFP manufactured fibre metal laminate structures under impact loading
- Author
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Serubibi, Arcade, Hazell, Paul J, Escobedo, Juan Pablo, Wang, Hongxu, Oromiehie, Ebrahim, and Prusty, Gangadhara B
- Published
- 2021
7. Post-gel polymerisation shrinkage profiling of polymer biomaterials using a chirped fibre Bragg grating
- Author
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Rajan, Ginu, Wong, Alex, Farrar, Paul, and Prusty, Gangadhara B.
- Published
- 2021
- Full Text
- View/download PDF
8. Distributed Fibre Optic Sensor-Based Continuous Strain Measurement along Semicircular Paths Using Strain Transformation Approach
- Author
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Prashanth Nagulapally, Md Shamsuddoha, Ginu Rajan, Luke Djukic, and Gangadhara B. Prusty
- Subjects
distributed sensing ,fibre optics ,structural health monitoring ,curved path strains ,Chemical technology ,TP1-1185 - Abstract
Distributed fibre optic sensors (DFOS) are popular for structural health monitoring applications in large engineering infrastructure because of their ability to provide spatial strain measurements continuously along their lengths. Curved paths, particularly semicircular paths, are quite common for optical fibre placement in large structures in addition to straight paths. Optical fibre sensors embedded in a curved path configuration typically measure a component of strain, which often cannot be validated using traditional approaches. Thus, for most applications, strain measured along curved paths is ignored as there is no proper validation tool to ensure the accuracy of the measured strains. To overcome this, an analytical strain transformation equation has been developed and is presented here. This equation transforms the horizontal and vertical strain components obtained along a curved semicircular path into a strain component, which acts tangentially as it travels along the curved fibre path. This approach is validated numerically and experimentally for a DFOS installed on a steel specimen with straight and curved paths. Under tensile and flexural loading scenarios, the horizontal and vertical strain components were obtained numerically using finite element analysis and experimentally using strain rosettes and then, substituted into the proposed strain transformation equation for deriving the transformed strain values. Subsequently, the derived strain values obtained from the proposed transformation equation were validated by comparing them with the experimentally measured DFOS strains in the curved region. Additionally, this study has also shown that a localised damage to the DFOS coating will not impact the functionality of the sensor at the remaining locations along its length. In summary, this paper presents a valid strain transformation equation, which can be used for transforming the numerical simulation results into the DFOS measurements along a semicircular path. This would allow for a larger scope of spatial strains measurements, which would otherwise be ignored in practice.
- Published
- 2021
- Full Text
- View/download PDF
9. A point source model to represent heat distribution without calculating the Joule heat during radiofrequency ablation
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Panchatcharam Mariappan, Gangadhara B, and Ronan Flanagan
- Abstract
Numerous liver cancer oncologists suggest bridging therapies to limit cancer growth until donors are available. Interventional radiology including radiofrequency ablation (RFA) is one such bridging therapy. This locoregional therapy aims to produce an optimal amount of heat to kill cancer cells, where the heat is produced by a radiofrequency (RF) needle. Less experienced Interventional Radiologists (IRs) require a software-assisted smart solution to predict the optimal heat distribution as both overkilling and untreated cancer cells are problematic treatments. Therefore, two of the big three partial differential equations, 1) heat equation (Pennes, Journal of Applied Physiology, 1948, 1, 93–122) to predict the heat distribution and 2) Laplace equation (Prakash, Open Biomed. Eng. J., 2010, 4, 27–38) for electric potential along with different cell death models (O’Neill et al., Ann. Biomed. Eng., 2011, 39, 570–579) are widely used in the last three decades. However, solving two differential equations and a cell death model is computationally expensive when the number of finite compact coverings of a liver topological structure increases in millions. Since the heat source from the Joule losses Qr = σ|∇V|2 is obtained from Laplace equation σΔV = 0, it is called the Joule heat model. The traditional Joule heat model can be replaced by a point source model to obtain the heat source term. The idea behind this model is to solve σΔV = δ0 where δ0 is a Dirac-delta function. Therefore, using the fundamental solution of the Laplace equation (Evans, Partial Differential Equations, 2010) we represent the solution of the Joule heat model using an alternative model called the point source model which is given by the Gaussian distribution.Qrx=∑xi∈Ω1K∑icie−|x−xi|22σ2where K and ci are obtained by using needle parameters. This model is employed in one of our software solutions called RFA Guardian (Voglreiter et al., Sci. Rep., 2018, 8, 787) which predicted the treatment outcome very well for more than 100 patients.
- Published
- 2022
10. Distributed Fibre Optic Sensor-Based Continuous Strain Measurement along Semicircular Paths Using Strain Transformation Approach
- Author
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Ginu Rajan, Gangadhara B Prusty, Luke P. Djukic, Shamsuddoha, and Prashanth Nagulapally
- Subjects
Materials science ,Optical fiber ,Acoustics ,Measure (physics) ,02 engineering and technology ,lcsh:Chemical technology ,01 natural sciences ,Biochemistry ,Article ,Analytical Chemistry ,law.invention ,Flexural strength ,law ,lcsh:TP1-1185 ,fibre optics ,Electrical and Electronic Engineering ,Instrumentation ,Computer simulation ,Strain (chemistry) ,structural health monitoring ,010401 analytical chemistry ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,Finite element method ,0104 chemical sciences ,Transformation (function) ,distributed sensing ,curved path strains ,Structural health monitoring ,0210 nano-technology - Abstract
Distributed fibre optic sensors (DFOS) are popular for structural health monitoring applications in large engineering infrastructure because of their ability to provide spatial strain measurements continuously along their lengths. Curved paths, particularly semicircular paths, are quite common for optical fibre placement in large structures in addition to straight paths. Optical fibre sensors embedded in a curved path configuration typically measure a component of strain, which often cannot be validated using traditional approaches. Thus, for most applications, strain measured along curved paths is ignored as there is no proper validation tool to ensure the accuracy of the measured strains. To overcome this, an analytical strain transformation equation has been developed and is presented here. This equation transforms the horizontal and vertical strain components obtained along a curved semicircular path into a strain component, which acts tangentially as it travels along the curved fibre path. This approach is validated numerically and experimentally for a DFOS installed on a steel specimen with straight and curved paths. Under tensile and flexural loading scenarios, the horizontal and vertical strain components were obtained numerically using finite element analysis and experimentally using strain rosettes and then, substituted into the proposed strain transformation equation for deriving the transformed strain values. Subsequently, the derived strain values obtained from the proposed transformation equation were validated by comparing them with the experimentally measured DFOS strains in the curved region. Additionally, this study has also shown that a localised damage to the DFOS coating will not impact the functionality of the sensor at the remaining locations along its length. In summary, this paper presents a valid strain transformation equation, which can be used for transforming the numerical simulation results into the DFOS measurements along a semicircular path. This would allow for a larger scope of spatial strains measurements, which would otherwise be ignored in practice.
- Published
- 2021
- Full Text
- View/download PDF
11. Post-gel polymerisation shrinkage profiling of polymer biomaterials using a chirped fibre Bragg grating
- Author
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Paul Farrar, Gangadhara B Prusty, Ginu Rajan, and Alex Wong
- Subjects
Dental composite ,Materials science ,Science ,01 natural sciences ,Spectral line ,Article ,010309 optics ,Biomaterials ,03 medical and health sciences ,0302 clinical medicine ,Fiber Bragg grating ,0103 physical sciences ,Composite material ,Curing (chemistry) ,chemistry.chemical_classification ,Multidisciplinary ,Strain (chemistry) ,030206 dentistry ,Polymer ,Temperature gradient ,chemistry ,Optical sensors ,Medicine ,Intensity (heat transfer) - Abstract
A strain profile measurement technique using a chirped fibre Bragg grating (CFBG) sensor by implementing an integration of differences (IOD) method is reported in this paper. Using the IOD method the spatial distribution of strain along the length of the CFBG is extracted from its power reflectance spectra. As a proof of concept demonstration, the developed technique is applied to measure the polymerisation shrinkage strain profile of a photo-cured polymer dental composite which exhibits a non-uniform strain distribution attributed to the curing lamp characteristics. The result from the CFBG technique is compared with that of an FBG array embedded in the dental composite and is correlated with the degree of conversion of the material which also depends on the curing lamp intensity distribution. This technology will have significant impact and applications in a range of medical, materials and engineering areas where strain or temperature gradient profile measurement is required in smaller scales.
- Published
- 2021
12. The effect of dental restoration geometry and material properties on biomechanical behaviour of a treated molar tooth: A 3D finite element analysis
- Author
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Gangadhara B Prusty, Victor Birman, Leon Prentice, Paul Shouha, Behzad Babaei, and Paul Farrar
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Molar ,Materials science ,medicine.medical_treatment ,Finite Element Analysis ,Isotropy ,Biomedical Engineering ,Geometry ,Finite element method ,Biomaterials ,Stress (mechanics) ,stomatognathic diseases ,stomatognathic system ,Mechanics of Materials ,medicine ,Humans ,Material properties ,Elastic modulus ,Dental restoration ,Stress concentration - Abstract
Objectives To test the hypothesis that restoration of class II mesio-occlusal-distal (MOD) cavities can be strengthened through judicious choice of restoration geometry and material properties. Methods An intact extracted human maxillary molar tooth was digitized, segmented, reconstructed, and four 3D restored tooth models were developed with four different restoration geometries: one straight, one single-curved, and two double-curved. Stress analysis was conducted for representative loading using finite element analysis, and maximum principal stresses were determined at the dentine-enamel and restoration-enamel junctions. A range of restorative material elastic moduli (5–80 GPa) and Poisson's ratios (0.25–0.35) were studied. Vertical loads of 400 N were applied on occlusal points, while the roots of the molar teeth, below the crevices, were supported in all directions. All the materials were modelled as homogeneous, isotropic, and elastic. Results The maximum principal stresses at the restoration-enamel junctions were strongly dependent on the MOD restoration geometries. Peak stresses occurred along the palatal surface of the restoration rather than the opposite buccal surface. Double-curved restorations showed the lowest peak stress at restoration-enamel junctions. Choice of the mechanical properties of restorative material in the range of 5–35 GPa further reduced stress concentrations on the enamel. Significance Class II MOD restorations may be stronger if designed with double-curved marginal geometries that can reduce stress concentrations. Designs with convex and concave geometries were particularly effective because they reduced stress concentrations dramatically. Results suggest that relatively minor changes to the geometry of a restoration can have a substantial effect on stress at the restoration-enamel junction and motivate future experimental analysis.
- Published
- 2022
13. Selective Atomic-Level Etching on Short S-Glass Fibres to Control Interfacial Properties for Restorative Dental Composites
- Author
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Cho, Kiho, Wang, Guannan, Raju, Raju, Fang, Jian, Rajan, Ginu, Stenzel, Martina, Farrar, Paul, Prusty, Gangadhara B, Cho, Kiho, Wang, Guannan, Raju, Raju, Fang, Jian, Rajan, Ginu, Stenzel, Martina, Farrar, Paul, and Prusty, Gangadhara B
- Abstract
Interfacial bonding between fibre and matrix is most critical to obtain enhanced mechanical properties of the resulting composites. Here we present a new surface tailoring method of selective wet etching and organosilicon monomers (3-(Trimethoxysilyl) propyl methacrylate, TMSPMA) deposition process on the short S-Glass fibre as a reinforcing material, resulting in increased mechanical retention and strong chemical bonding between glass fibres and polymer resin (a mixture of triethylene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA) monomers). The effect of surface modification on fibre matrix interfacial strength was investigated through microdroplet tests. An S-Glass fibre treated with piranha solution (a mixture of H2O2 and H2SO4) for 24 hours followed by TMSPMA surface silanization shows highest increase up to 39.6% in interfacial shear strength (IFSS), and critical fibre length could be reduced from 916.0 µm to 432.5 µm. We find the optimal surface treatment condition in that the flexural strength of dental composites reinforced by the S-Glass fibres enhanced up to 22.3% compared to the composites without fibre surface treatments. The significant elevation in strength is attributed to changes in the surface roughness of glass fibres at atomic scale, specifically by providing the multiplied spots of the chemical bridge and nano-mechanical interlocking. The findings offer a new strategy for advanced tailoring of short S-Glass fibres to maximise the mechanical properties of biomedical and dental composites.
- Published
- 2019
14. Polymerisation Shrinkage Profiling of Dental Composites using Optical Fibre Sensing and their Correlation with Degree of Conversion and Curing Rate
- Author
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Rajan, Ginu, Raju, Raju, Jinachandran, Sagar, Farrar, Paul, Xi, Jiangtao, Prusty, Gangadhara B, Rajan, Ginu, Raju, Raju, Jinachandran, Sagar, Farrar, Paul, Xi, Jiangtao, and Prusty, Gangadhara B
- Abstract
Traditional polymerisation shrinkage (PS) measurement systems measure average PS of dental composites, but the true local PS varies along the length and breadth of the composite. The PS depends on the curing light intensity distribution, resultant degree of conversion (DOC) and the curing rate. In this paper, optical fibre Bragg grating (FBG) sensing based technology is used to measure the linear post-gel PS at multiple locations within dental composite specimens, and is correlated with DOC and curing rate. A commercial dental composite is used, and its post-gel PS and DOC are mapped using embedded fibre Bragg grating sensors at different curing conditions. The distance between the curing lamp and the composite specimen is varied which resulted in different intensity distribution across the specimen. The effect of curing light intensity distribution on PS, curing rate and DOC are investigated for demonstrating a relationship among them. It is demonstrated that FBG sensing method is an effective method to accurately profiling post-gel PS across the specimen.
- Published
- 2019
15. Effect of fibre architecture on the specific energy absorption in carbon epoxy composite tubes under progressive crushing
- Author
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Jacek Tarasiuk, Sebastian Wroński, Gangadhara B Prusty, Grażyna Ryzińska, and Matthew David
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Materials science ,Composite number ,chemistry.chemical_element ,02 engineering and technology ,Epoxy ,021001 nanoscience & nanotechnology ,020303 mechanical engineering & transports ,0203 mechanical engineering ,chemistry ,Woven fabric ,visual_art ,Ceramics and Composites ,Specific energy absorption ,Loading rate ,visual_art.visual_art_medium ,Composite material ,0210 nano-technology ,Wall thickness ,Carbon ,Mass fraction ,Civil and Structural Engineering - Abstract
This paper presents the progressive crushing performance of composite tubes with varied fibre architecture. The effect of lay-up configuration and influence of percentage of unidirectional (UD) and woven fabric (WF) fibre architectures on the specific energy absorption (SEA) is investigated using experiments. Composite tubes with internal diameter 42 mm and wall thickness to diameter of 0.05 were manufactured for a range of specimens with different ratios of axial and hoop fibres. The samples were chamfered at an angle of 70°. Progressive crushing of specimens under quasi-static (20 mm/min) and dynamic (4.48–6.7 m/s) loading were performed. A new factor Axial Fibre Mass Fraction (AFMF) was introduced to describe the mass fraction of axial fibres to reflect upon the SEA response. To investigate the influence of AFMF and loading rate on the crushing mechanism of composite tubes, computer tomography (CT) was additionally. The calculated SEA for different loading conditions indicate a drop of 10%–20% for dynamic cases depending on the fibre architecture of the samples. The CT-scans present a relationship between debris length and AFMF. The average length of debris decreases with the increase of AFMF which indicates more intense fibre breaking, reduced integrity of the ‘petals’ and hence increased SEA.
- Published
- 2019
16. Improved stochastic methods for modelling imperfections for buckling analysis of composite cylindrical shells
- Author
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Gangadhara B Prusty, Richard Degenhardt, Jendi Kepple, Rodney S. Thomson, Garth Pearce, and Manudha T. Herath
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Engineering ,Buckling ,business.industry ,Stochastic modelling ,Stochastic process ,Shell (structure) ,Cylinder ,Structural engineering ,Aerospace ,business ,Axial symmetry ,Finite element method ,Civil and Structural Engineering - Abstract
Imperfection sensitive CFRP cylindrical shells are used in a variety of civil and aerospace applications and feature a large scatter in buckling load levels induced from imperfections introduced from their manufacture. Currently, there are no complete methods that can realistically simulate cylinders with a full spectrum of imperfection types for a complete diagnosis of possible buckling loads. This forces shell designers to utilise an outdated, inefficient and conservative design philosophy that is unsuitable for modern manufacturing methods and materials. Stochastic analyses can optimise and improve the robust design and reliability of such cylinders through accurate prediction of the range of conceivable buckling loads by realistic simulation of structural imperfections. Such imperfections include initial shell-wall geometric, thickness and material imperfections and non-uniform applied end-loads. A procedure which aims to improve the stochastic modelling of thickness and material imperfections in imperfection sensitive composite cylindrical shells is proposed. Monte-Carlo simulations of axially compressed cylinders are performed to show that the stochastic methods described here are able to capture the scatter introduced from the imperfections. The results show that the axial buckling load of the specific cylinder analysed here can be reduced to 29.5 kN and increased to over 40 kN from a perfect load of 38.2 kN from material and thickness imperfections alone.
- Published
- 2015
17. Automated fibre placement based composite structures: Review on the defects, impacts and inspections techniques
- Author
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Ebrahim Oromiehie, Ginu Rajan, Gangadhara B Prusty, and Paul Compston
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Computer science ,Melting temperature ,Composite number ,Structural integrity ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Reliability engineering ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Random defects ,Ceramics and Composites ,Laminated composites ,Manufacturing methods ,0210 nano-technology ,Civil and Structural Engineering - Abstract
Automated fibre placement (AFP) offers high throughput, efficient and accurate manufacturing methods for making multi-stiffened laminated composites. However, processing conditions, machine tolerances and steering of tape can induce small random defects within the laminate, which may compromise the structural integrity. Thus, this paper presents a comprehensive review on the processing/steering-induced defects in AFP and their influence on the quality of the final product. Three key processing parameters in AFP, specifically consolidation force, lay-up speed and curing/melting temperature are attempted elaborately. Additionally, the paper attempted to present the discussions on in-situ process monitoring as well as the Machine Learning (ML) based predictive models for AFP based composites.
- Published
- 2019
18. Neural network modelling for damage behaviour of composites using full-field strain measurements
- Author
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Gangadhara B Prusty and Hou Man
- Subjects
Engineering ,Artificial neural network ,business.industry ,Constitutive equation ,Structural engineering ,Fibre-reinforced plastic ,Parameter space ,Strain energy ,Nonlinear system ,Ceramics and Composites ,Composite material ,business ,Civil and Structural Engineering ,Tensile testing ,Free energy principle - Abstract
This paper presents a neural network modelling method for damage behaviour of composite materials in conjunction with full-field strain measurements. The proposed method utilises the overall structural response of a laminate composite specimen to develop the constitutive model of a single ply unidirectional laminate. Based on an energy principle, a performance function for training the neural networks is derived in terms of the applied external work and the induced strain energy. This allows the proposed method to develop the neural networks without the presence of stress information that is not necessarily obtainable in experiments with non-uniform deformation. The use of neural networks also enables the proposed method to model the damage behaviour without the constraints on the parameter space, such that a more representative model is developed for the actual material behaviour. An example of tailoring the proposed method to model the in-plane shear damage behaviour of a carbon fibre reinforced plastic (CFRP) laminate is demonstrated as well as its numerical validation. The practical application of the proposed method to multi-axial damage-related nonlinear behaviour of composite is presented using the experimental data obtained from a tensile test with an open-hole specimen.
- Published
- 2011
19. Thermal sensitivity and relaxation of carbon fibre-foam sandwich composites with fibre optic sensors
- Author
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Oromiehie, Ebrahim, Rajan, Ginu, Prusty, Gangadhara B, Oromiehie, Ebrahim, Rajan, Ginu, and Prusty, Gangadhara B
- Abstract
The increasing use of sandwich composites for structural applications brings with it a need to establish a reliable inspection and monitoring method to ensure structural integrity and safe operation throughout the service life. Since optical fibre-based photonic sensing technologies are increasingly common for structural health monitoring of composite structures, selection of optical fibre Bragg grating sensors could be one possible choice for this purpose. In this paper, performance characterisation of sandwich composite with embedded silica fibre Bragg grating sensor is reported. Experimental tests were performed on a carbon fibre foam core sandwich composite embedded with a silica fibre Bragg grating sensor to extract the structural health monitoring parameters such as strain and temperature. The current study found that sandwich composite exhibits foam relaxation; however, its impact on strain measurement is negligible. Another important finding from the theoretical and the experimental thermal modelling was that although the constituent components of the sandwich composite have entirely different thermal expansion coefficients, its effect on the embedded fibre sensor can be minimal if the sensors are embedded between the face sheets. These results can initiate further research in this area and can lead to the development of state-of-the art structural health monitoring techniques for sandwich composite structures.
- Published
- 2016
20. Fibre Bragg grating sensing technology for the evaluation of physical properties of dental resin composites
- Author
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Rajan, Ginu, Shouha, Paul, Ellakwa, Ayman, Xi, Jiangtao, Prusty, Gangadhara B, Rajan, Ginu, Shouha, Paul, Ellakwa, Ayman, Xi, Jiangtao, and Prusty, Gangadhara B
- Abstract
The characterization of the physical properties of dental resin composites is fraught with difficulties relating to significant intra and inter test parameter variabilities and is relatively time consuming and expensive. The main aim of this study was to evaluate whether optical fibre Brag grating (FBG) sensing system may become a viable tool to study dental material characteristics. Of particular focus was the potential for the system to demonstrate a multi parameter all-in-one feature. A miniature FBG was embedded in six different dental resin composites and employed as a sensor to evaluate linear polymerization shrinkage, thermal expansion and water sorption. This study demonstrates how optical fibre technology can provide simple and reliable methods of measuring the critical physical properties of dental composites. In addition due to the embedding and preservation of the sensor within the samples multiple parameters can be tested for with the same sample.
- Published
- 2016
21. Intrinsic high-sensitivity sensors based on etched single-mode polymer optical fibres
- Author
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Bhowmik, Kishore, Peng, Gang-Ding, Ambikairajah, Eliathamby, Lovric, Vedran, Walsh, William R, Prusty, Gangadhara B, Rajan, Ginu, Bhowmik, Kishore, Peng, Gang-Ding, Ambikairajah, Eliathamby, Lovric, Vedran, Walsh, William R, Prusty, Gangadhara B, and Rajan, Ginu
- Abstract
The significance of etched single-mode polymer optical fibers and their potential for the development of highsensitivity sensors are presented. A polymethyl methacrylatebased single-mode polymer optical fiber is etched to various diameters and it is observed that etching can lead to change in the material properties of the fiber, such as Young's modulus and thermal expansion coefficient. This can play a vital role in improving the intrinsic sensing capabilities of sensors based on etched polymer optical fiber. To demonstrate that the modified material properties of the etched polymer fiber can enhance its intrinsic sensing capabilities, sensing characteristics of etched polymer fiber Bragg gratings for strain, temperature, and pressure are obtained. From the results, it is confirmed that the sensors based on etched polymer fibers exhibit high intrinsic sensitivity compared with un-etched ones. The potential of developing a sensing system for simultaneous measurement of strain and temperature is also demonstrated.
- Published
- 2015
22. Growth response of Catla catla (Actinopterygii: Cypriniformes: Cyprinidae) to soya and maize supplemented traditional feed mixture
- Author
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Priyadarshini, M., Manissery, J.K., Gangadhara, B., Rao, L.M., and Keshavanath, P.
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feed mixture ,Catla catla ,growth ,food and beverages ,digestive enzyme activity ,carcass composition - Abstract
Background. In Indian carp culture, a 1 : 1 mixture of rice bran and oil cake is traditionally used as feed in powder form; it is nutritionally inadequate and also a large part of it goes unutilized as the fish cannot feed on the powder effectively. With a view to improve its nutritional quality and reduce the wastage, the mixture was supplemented with soya and maize flours and converted into pellet form. The performance of the supplemented diets was evaluated by feeding them to catla, Catla catla, one of the popular Indian major carps. Materials and methods. Two test diets were formulated supplementing the feed mixture with soya flour (10% and 20%) and maize flour (39%), replacing equal quantities of rice bran and oilcake. These diets along with the control diet were fed to triplicate groups of catla fry maintained in outdoor cement tanks for 120 days. Results. The test diets enhanced growth and net fish production significantly (P < 0.05). This resulted in higher economic returns under the two test treatments. Survival of fish ranged from 74% to 76%. Carcass of fish receiving the test diets had significantly (P < 0.05) higher lipid and lower moisture levels. Digestive enzyme activity was affected positively (P < 0.05) by the test diets. Conclusion. Replacing rice bran and oilcake from the traditional feed mixture with soya and maize flours proved economically viable.
- Published
- 2011
23. Adaptive tutorials to target threshold concepts in mechanics — a community of practice approach
- Author
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Prusty, Gangadhara B, Russell, Carol, Ford, Robin, Ben-Naim, Dror, Ho, Shaowei, Vrcelj, Zora, Marcus, Nadine, McCarthy, Timothy, Goldfinch, Tom, Ojeda, Roberto, Gardner, Anne, Molyneaux, Tom, Hadgraft, Roger, Prusty, Gangadhara B, Russell, Carol, Ford, Robin, Ben-Naim, Dror, Ho, Shaowei, Vrcelj, Zora, Marcus, Nadine, McCarthy, Timothy, Goldfinch, Tom, Ojeda, Roberto, Gardner, Anne, Molyneaux, Tom, and Hadgraft, Roger
- Abstract
We present our work on introducing Adaptive Tutorials in first and second year mechanics courses in Engineering. Adaptive Tutorials are interactive online modules where an Intelligent Tutoring System adapts the instruction level to learners, based on their individual performance. Through an ALTC-funded project, we formed a community of practice of Engineering Mechanics educators from a range of Australian universities. As a team, we began by identifying Threshold Concepts that if they are not grasped inhibit students’ learning before developing a set of Adaptive on-line Tutorials to target them. These Adaptive Tutorials were used by students throughout the first half of 2011, and were found to be both engaging and conducive to learning. In this paper, we present our approach and findings and discuss our strategy of giving educators pedagogical control over such advanced technologically-based instructional methods with the goal of increasing adoption and ultimately improving students learning.
- Published
- 2011
24. Robotic infraclavicular approach for minimally invasive neck dissection in head-neck cancers.
- Author
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Khan A, Reddy VS, Gangadhara B, Mayur M, Barad A, Munisiddaiah D, Ramakrishnan A, Sadhoo A, and Nayak SP
- Abstract
Background: In the recent years, there has been a rapid increase in the use of robot assisted neck dissection (RAND) as an alternative method for conventional neck dissection. Several recent reports have emphasized upon the feasibility and effectiveness of this technique. However, substantial technical and technological innovation is still essential in spite of the availability of multiple approaches for RAND., Materials and Methods: The present study describes a novel technique, i.e., Robotic Infraclavicular Approach for Minimally Invasive Neck Dissection (RIA MIND) used in head and neck cancers with the help of Intuitive da Vinci Xi Surgical System., Results: After RIA MIND procedure, the patient was discharged on the third post operative day. Also, the total wound size was less than 3.5 cm which enhanced the patient recovery time and required minimal post operative care. The patient was further reviewed 10 days after the procedure for the removal of sutures., Conclusion: RIA MIND technique was effective and safe for performing neck dissection for oral, head and neck cancers. However, additional detailed studies will be required for establishing this technique., Competing Interests: None
- Published
- 2023
- Full Text
- View/download PDF
25. Efficacy and Safety of Novel Minimally Invasive Neck Dissection Techniques in Oral/Head and Neck Cancer: A Systematic Review and Meta-Analysis.
- Author
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Nayak SP, Sreekanth Reddy V, Gangadhara B, and Sadhoo A
- Abstract
Despite minimally invasive neck dissection (MIND) being popular technique, there is a paucity of literature emphasizing its safety and efficacy. In this meta-analysis, we compared the efficacy and safety of MIND over CND techniques in treating oral/head and neck cancer. We systematically searched PubMed, MEDLINE, Embase, from database inception to January, 2019 for the relevant studies comparing MIND and CND. Two independent reviewers performed quality check and data were extracted for primary outcomes to assess length of hospital stay, duration of surgery, intraoperative blood loss and retrieved lymph nodes. Drainage volume and duration, length of incision, satisfaction of scar and safety were the secondary outcomes. We analyzed the outcomes using standard mean differences (SMDs) and the relative risk that were pooled using random effect meta-analysis. Out of 144 studies, 17 met the final inclusion criteria. MIND technique has shown better overall efficacy with outcomes compared to CND except with duration of surgery (SMD 1.82, 95% CI 0.47-3.17). Lesser hospital stay, better nodal yield and less intra-operative blood loss was observed with MIND over CND. Duration and volume of wound drainage was comparably less in MIND with smaller length of incision. Postoperative complications were less and tolerable with MIND approach with superior cosmetic outcomes. MIND via endoscopic or robotic approach is safe and efficacious with equitable oncological outcomes in terms of lymph nodes yield compared to CND, but it requires longer surgery duration., Competing Interests: Conflicts of interestThe authors declare that they have no conflicts of interest., (© Association of Otolaryngologists of India 2020.)
- Published
- 2022
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