34 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. Stability analysis for the discrete finite element model of the Pennes bio-heat equation.
- Author
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Gangadhara, B. and Panchatcharam, Mariappan
- Subjects
- *
FINITE element method , *ABLATION techniques , *STABILITY criterion , *EQUATIONS , *THERMAL properties - Abstract
The bio-heat equation is a popular tool for determining how heat is distributed in living organisms. Moreover, the Pennes bio-heat equation is crucial in the field of ablation therapy computation. Using the finite element approach, we investigated the stability criteria for the bio-heat equation in this article. In a semi-discretized finite element formulation, first-order difference techniques are employed to discretize the time derivative term. When the implicit scheme is replaced with the explicit scheme, the time step becomes reliant on the thermal properties of the tissue and the eigenvalue of the global matrix. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Novel Response Surface Technique for Composite Structure Localization Using Variable Acoustic Emission Velocity.
- Author
-
Bhandari, Binayak, Maung, Phyo Thu, and Prusty, Gangadhara B.
- Subjects
SPEED of sound ,COMPOSITE structures ,ACOUSTIC emission ,COMPOSITE plates ,STRUCTURAL health monitoring ,STANDARD deviations ,LAMINATED materials - 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. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. Post-gel polymerisation shrinkage profiling of polymer biomaterials using a chirped fibre Bragg grating
- Author
-
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
7. 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
8. 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
9. 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
10. Adaptive tutorials to target threshold concepts in mechanics - a community of practice approach
- Author
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Australasian Association for Engineering Education (22nd : 2011 : Fremantle, W.A.), 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
- Published
- 2011
11. Can More Become Less? Effects of an Intensive Assessment Environment on Students' Learning Performance
- Author
-
Khawaja, M. Asif, Prusty, Gangadhara B., Ford, Robin A. J., Marcus, Nadine, and Russell, Carol
- Abstract
Online interactive systems offer the beguiling prospect of an improved environment for learning at minimum extra cost. We have developed online interactive tutorials that adapt the learning environment to the current learning status of each individual student. These Adaptive Tutorials (ATs) modify the tasks given to each student according to their previous responses. Feedback, assessment and remediation are also adapted. Over a three-year period we progressively blended ATs into notoriously challenging courses in introductory Engineering Mechanics. We assessed the impact of this initiative by reviewing three lines of data: (i) the built-in diagnostics of the system, (ii) changes in student grades from year-to-year and (iii) supplementary surveys. Generally, students liked the new blended system and grades improved. Detailed analysis revealed nuances in the measures of student learning, such as differences between high-performing and low-performing students. With these insights we are able to further adapt the system to meet the learning needs of our students.
- Published
- 2013
- Full Text
- View/download PDF
12. Mechanical and optical performance evaluations of embedded polyimide and PEEK coated distributed optical sensors in glass fibre reinforced composites with vinyl ester resin systems.
- Author
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Nagulapally, Prashanth, Shamsuddoha, Md, Herath, Thinu, Djukic, Luke, and Prusty, Gangadhara B
- Subjects
VINYL ester resins ,OPTICAL sensors ,FIBER optical sensors ,FIBROUS composites ,DISTRIBUTED sensors ,POLYETHER ether ketone ,OPTICAL coatings - Abstract
Embedded optical fibre sensors (OFSs) offer the potential to monitor the internal strains at various stages during the manufacturing and service life of fibre-reinforced polymer (FRP) composite structures. Various aspects associated with the embedment of OFSs, such as integration, material compatibility, and sensing performance of the embedded sensor needs to be investigated to develop reliable OFSs based internal sensing platform for composite structures. In this study, Polyimide (PI) and Polyether ether ketone (PEEK) coated optical fibres (OF) were embedded into glass fibre-reinforced polymer (GFRP) composites to evaluate four important aspects associated with the embedment of OFs, which include; i). Structural integrity of the OFs against chemical reactions from vinyl ester resin and its additives through immersion testing, ii). Methods of integrating the OFs into layered glass fibres for the vacuum resin infusion manufacturing process, iii). Sensing performance of the embedded OFs during manufacturing and structural testing (tensile and compressive), and iv). Internal structural integrity of the embedded OFs and the host composite structure using X-Ray micro-computerised tomography technique (μ-CT). The results from the immersion testing and manufacturing process monitoring showed that both PEEK and PI coated OFs can resist the chemical and mechanical stresses caused by resin polymerisation during curing process. The subsequent mechanical testing showed a similar sensing performance by the PI and PEEK coated OFs. Under tensile loads, the OFs monitored the tensile strain distribution up to 7,000 με and compressive strain distribution up to −1,200 με under flexural loading without compromising their optical performance. Finally, the μ-CT scanning results had shown a minimal structural deterioration of the embedded OFs and host composite structure. The outcomes from this detailed experimental investigation on the embedment of OFS in GFRP structures provided useful information towards the integration and performance of optical sensors in composite structures. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
13. Distributed Fibre Optic Sensor-Based Continuous Strain Measurement along Semicircular Paths Using Strain Transformation Approach
- Author
-
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
14. Post-gel polymerisation shrinkage profiling of polymer biomaterials using a chirped fibre Bragg grating
- Author
-
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
15. Growth performance of two Indian major carps, catla [formula omitted] and rohu [formula omitted] fed diets containing different levels of Spirulina platensis
- Author
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Nandeesha, M.C, Gangadhara, B, Manissery, J.K, and Venkataraman, L.V
- Published
- 2001
- Full Text
- View/download PDF
16. Effect of Ultrasonic Peening on Fatigue Crack Propagation from a Weld Toe
- Author
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Hellier, Alan Keith, Gangadhara B Prusty, Pearce, Garth, Reid, Mark, and Paradowska, Anna
- Published
- 2016
- Full Text
- View/download PDF
17. 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.
- Subjects
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
18. Thermal sensitivity and relaxation of carbon fibre-foam sandwich composites with fibre optic sensors.
- Author
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Oromiehie, Ebrahim, Rajan, Ginu, and Prusty, Gangadhara B.
- Subjects
THERMAL analysis ,CARBON fibers ,CARBON foams ,SANDWICH construction (Materials) ,OPTICAL fiber detectors ,BRAGG gratings - 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. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
19. Can more become less? Effects of an intensive assessment environment on students’ learning performance.
- Author
-
Khawaja, M. Asif, Prusty, Gangadhara B., Ford, Robin A.J., Marcus, Nadine, and Russell, Carol
- Subjects
- *
COMPUTER assisted instruction , *GRADING of students , *INTERNET in education , *MECHANICS (Physics) -- Study & teaching , *ENGINEERING education in universities & colleges , *ENGINEERING education , *HIGHER education - Abstract
Online interactive systems offer the beguiling prospect of an improved environment for learning at minimum extra cost. We have developed online interactive tutorials that adapt the learning environment to the current learning status of each individual student. These Adaptive Tutorials (ATs) modify the tasks given to each student according to their previous responses. Feedback, assessment and remediation are also adapted. Over a three-year period we progressively blended ATs into notoriously challenging courses in introductory Engineering Mechanics. We assessed the impact of this initiative by reviewing three lines of data: (i) the built-in diagnostics of the system, (ii) changes in student grades from year-to-year and (iii) supplementary surveys. Generally, students liked the new blended system and grades improved. Detailed analysis revealed nuances in the measures of student learning, such as differences between high-performing and low-performing students. With these insights we are able to further adapt the system to meet the learning needs of our students. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
20. Free and forced vibration analysis using improved third-order shear deformation theory for functionally graded plates under high temperature loading.
- Author
-
Wattanasakulpong, Nuttawit, Prusty, Gangadhara B, and Kelly, Donald W
- Subjects
- *
FORCED vibration (Mechanics) , *SHEAR (Mechanics) , *FUNCTIONALLY gradient materials , *HIGH temperatures , *THICKNESS measurement , *RITZ method , *DYNAMIC loads - Abstract
An improved third-order shear deformation theory is employed to investigate free and forced vibration responses of functionally graded plates. A power law distribution is used to describe the variation of material compositions across the plate thickness. The governing equations for vibration analysis obtained using an energy approach are then solved using the Ritz method. Two types of solutions, temperature independent and dependent material properties, are considered. Many effects of the volume fraction index, temperature, material pairs, thickness, plate aspect ratio, etc., which have significant impact on dynamic behaviour of the plates, are considered in the numerical illustrations of free and forced vibration results. At high temperatures, it is observed that the maximum deflections of the functionally graded plates subjected to the dynamic loading increase with the increase of frequency ratio and temperature. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
21. Evaluation of Four Biodegradable Substrates for Periphyton and Fish Production.
- Author
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Keshavanath, P., Manissery, J.K., Bhat, A.Ganapathi, and Gangadhara, B.
- Subjects
PERIPHYTON ,FISH farming ,CHEMICAL decomposition ,SUGARCANE ,POLY-aquaculture ,CARP ,ROHU - Abstract
Four locally available biodegradable substrates—sugarcane (Saccharum officinales) bagasse, palm (Borasus flabellifera) leaf, coconut (Cocos nucifera) leaf, and bamboo (Bambusa bambos) mat—were evaluated for the production of periphyton and a polyculture of rohu (Labeo rohita) and common carp (Cyprinus carpio) in poultry-manured ponds. Chlorophyll-a, phaeophytin-a, and total pigment content of periphyton were not significantly different (P > 0.05) among substrate types. Dry matter and ash-free dry matter of coconut leaf periphyton were significantly higher (P < 0.05) than that of the other substrates. All four substrates induced significantly (P < 0.05) higher growth, production, and survival of rohu and common carp. Among the substrates used, coconut leaf was more effective in enhancing fish production. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
22. Planktonic and Biochemical Composition of Periphyton Grown on Some Biodegradable and Non-Degradable Substrates.
- Author
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Gangadhara, B. and Keshavanath, P.
- Subjects
- *
PLANKTON , *AQUATIC invertebrates , *ZOOPLANKTON , *BIOCHEMISTRY , *AQUATIC biology , *AQUACULTURE - Abstract
Ten locally available substrates, five biodegradable and five non-degradable, were evaluated for their potential to harbor periphyton in cement tanks fertilized with poultry manure. The tanks were fertilized regularly and the periphyton was allowed to grow for 70 days. Weekly samples of periphyton and plankton were collected for enumeration and biochemical analyses. Among the substrates, earthen tiles harbored negligible amount of periphyton. The phytoperiphyton genera encountered on the substrate belonged mainly to Chlorophyceae (14 genera), followed by Cyanophyceae (2 genera), Chrysophyceae (1 genus), Bacillariophyceae (1 genus), and Dinophyceae (1 genus). Nauplius, Keratella, Diaptomus, Cyclops, Moina, Chironomus and insect eggs were the zooplankton encountered on substrates. Phytoplankton density was higher on tyre (86,426 cells or colonies/cm²) and palm leaf (85,808 cells or colonies/cm²) and lowest on ceramic tile (21,081 cells or colonies/cm²). Glass plates harbored the highest number of zooplankton species per unit area (1050 cells or colonies/cm²), while arecanut leaf-sheath had the lowest (210 cells or colonies/cm²). All five families of phytoplankton present on the substrates were also present in tank water. While periphyton contained 26 genera, tank water had only 24. Periphytic dry matter, ash, ash-free dry matter, plankton density on substrates and water showed a general increase with respect to time. Polyvinyl chloride (PVC) (0.972 mg/cm²), glass (0.913 mg/cm²), and bamboo (0.897 mg/cmsup2;) had higher periphytic dry matter and ceramic tile (0.262 mg/cm²) the lowest. All the proximate composition parameters of periphyton, except nitrogen free extract (NFE) varied significantly (P < 0.05) between the substrates. The moisture content of periphyton ranged from 85.58% (bamboo) to 95.27% (arecanut leaf-sheath). Crude protein was high in periphyton from bamboo (3.77%) and tyre (3.66%) and low in that from arecanut leaf-sheath (0.99%). [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
23. Growth Response and Biochemical Composition of Rohu, Lebeo rohita, Fed Salt-Incorportated Diets.
- Author
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Gangadhara, B., Nandeesha, M. C., Keshavanath, P., and Varghese, T. J.
- Subjects
- *
SALT , *ROHU , *FISH food , *FISH feeds , *WEIGHT gain , *FISH farming - Abstract
Rohu, Labeo rohita, fingerlings (av. wt. 1.6 g) were fed pelleted diets supplemented with 0, 0.5, 1.0, 1.5 and 2.0% sodium chloride (NaCl) for 120 days in 25-m3 cement tanks. The final weight gain of fish fed 0.5 and 1.0% NaCl incorporated diets was significantly (P < 0.05) higher than that of the control (0% NaCl). Net protein retention and carcass protein and fat contents were higher under different treatments as compared to the control. Growth indices and carcass composition indicate inclusion of 1.0% NaCl in the diet to be beneficial for growth promotion in rohu. [ABSTRACT FROM PUBLISHER]
- Published
- 2004
- Full Text
- View/download PDF
24. Digestibility of Bamboo-Grown Periphyton by Carps (Catla catla, Labeo rohita, Cirrhinus mrigala, Cyprinus carpio, Ctenopharyngodon idella, Tor khudree) and Hybrid Red Tilapia (Oreochromis mossambicus x O. niloticus).
- Author
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Gangadhara, B., Keshavanath, P., Ramesha, T. J., and Priyadarshini, M.
- Subjects
- *
PERIPHYTON , *AQUATIC invertebrates , *BAMBOO , *GRASSES , *APOCLADA , *CARP - Abstract
Periphyton development on bamboo substrate was quantified over six weeks in fertilized mud-bottomed cement tanks. Dry matter, ash and pigment content of periphyton were analyzed at weekly intervals. On dry matter basis, periphyton production reached the maximum on the 21st day and showed a decline thereafter. Periphyton was scraped and fed ad libitum daily over 30 days to fingerlings of cultivable carps (catla, rohu, mrigal, common carp, grass carp and mahseer) and hybrid red tilapia maintained in aerated fibreglass tanks, to evaluate digestibility. Dry matter digestibility was highest (P < 0.05) with mahseer (42.54%) and lowest with catla (20.63%). The values obtained with grass carp, red tilapia, rohu, and mrigal were not significantly different from that of mahseer and common carp. Protein digestibility was highest in grass carp (71.21%) and lowest in common carp (48.81%). Further, protein digestibility in catla, rohu and mrigal was similar. The results of this study would be useful in the selection of fish species for periphytonbased aquaculture. [ABSTRACT FROM PUBLISHER]
- Published
- 2004
- Full Text
- View/download PDF
25. Digestibility of Bamboo-Grown Periphyton by Carps (Catla catla, Labeo rohita, Cirrhinus mrigala, Cyprinus carpio, Ctenopharyngodon idella, Tor khudree) and Hybrid Red Tilapia (Oreochromis mossambicus x O. niloticus).
- Author
-
Gangadhara, B., Keshavanath, P., Ramesha, T. J., and Priyadarshini, M.
- Subjects
PERIPHYTON ,AQUATIC invertebrates ,BAMBOO ,GRASSES ,APOCLADA ,CARP - Abstract
Periphyton development on bamboo substrate was quantified over six weeks in fertilized mud-bottomed cement tanks. Dry matter, ash and pigment content of periphyton were analyzed at weekly intervals. On dry matter basis, periphyton production reached the maximum on the 21st day and showed a decline thereafter. Periphyton was scraped and fed ad libitum daily over 30 days to fingerlings of cultivable carps (catla, rohu, mrigal, common carp, grass carp and mahseer) and hybrid red tilapia maintained in aerated fibreglass tanks, to evaluate digestibility. Dry matter digestibility was highest (P < 0.05) with mahseer (42.54%) and lowest with catla (20.63%). The values obtained with grass carp, red tilapia, rohu, and mrigal were not significantly different from that of mahseer and common carp. Protein digestibility was highest in grass carp (71.21%) and lowest in common carp (48.81%). Further, protein digestibility in catla, rohu and mrigal was similar. The results of this study would be useful in the selection of fish species for periphytonbased aquaculture. [ABSTRACT FROM PUBLISHER]
- Published
- 2004
- Full Text
- View/download PDF
26. Further studies on the use of mixed feeding schedules with plant-and animal-based diets for common carp Cyprinus carpio (Linnaeus).
- Author
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Nandeesha, M. C., Gangadhara, B., and Manissery, J. K.
- Subjects
- *
COLOCASIA , *CARP , *GROWTH , *ANIMAL nutrition , *DIET - Abstract
A growth trial was conducted on common carp Cyprinus carpio (L.) fry in cement tanks for 100 days in order to test the efficacy of mixed feeding schedules. The diets tested were a fishmeal-based diet (diet D with 30.9% protein) and three Colocasia esculenta-based diets (diet A with 16.7% protein, diet B with 19.7% protein and diet C with 25.8% protein) separately and in three mixed feeding combinations of diet A, B and C with D on alternate 2 days (2A/2D, 2B/2D and 2C/2D, where the numeral indicates the number of days that the particular diet was offered continuously). The results revealed no difference in growth of common carp fed the plant protein-based diets A and B (P > 0.05). Although the fish fed on diets C and D and mixed feeding combinations 2A/2D and 2B/2D performed comparably and higher than those on diets A and B, the schedule 2C/2D resulted in the highest final weight. Specific growth rate, feed conversion ratio and RNA/DNA ratios were the highest in the 2C/2D schedule. Among the mixed feeding schedules, the highest saving in protein and cost was recorded with the 2A/2D schedule, followed by 2B/2D and 2C/2D. An increase in dietary protein led to decreased protein and increased fat deposition in the carcass. An increasing trend in the protease and amylase activities was recorded with increased dietary protein level. The study highlighted the efficient utilization of plant proteins by common carp under mixed feeding schedules. [ABSTRACT FROM AUTHOR]
- Published
- 2002
- Full Text
- View/download PDF
27. Evaluation of carbohydrate rich diets through common carp culture in manured tanks.
- Author
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KESHAVANATH, P, MANJAPPA, K, and GANGADHARA, B
- Subjects
HIGH-carbohydrate diet ,CARP - Abstract
Four diets (T
0 –T3 ) were formulated reducing the fishmeal (Indian) component by 100 g kg–1 from 300 to 0 g kg–1 and including proportionately increasing quantities of maize. Diets were fed for 120 days at 50 g kg–1 body weight to triplicate groups of common carp (av. wt. 2.11–2.18 g) stocked at 1 m–2 in mud bottomed cement tanks (18 m2 ), fertilized with poultry manure. Fish growth, SGR and FCR in the different treatments were statistically not significantly different (P > 0.05). PER was lowest for the 300 g fishmeal kg–1 diet treatment (diet T0 ), increasing with decrease in dietary fishmeal content (diets T1 –T3 ). Fish survival ranged from 96.29 to 100%. Diets influenced carcass composition and digestive enzyme activity. A significant increase in lipid deposition was recorded with increasing dietary carbohydrate content. Amylase, protease and lipase activities were higher in fish fed with diets T2 and T3 . The protein sparing effect of dietary carbohydrate and the economic implication of eliminating fishmeal from the diet are discussed. [ABSTRACT FROM AUTHOR]- Published
- 2002
- Full Text
- View/download PDF
28. Evaluation of sugarcane by-product pressmud as a manure in carp culture
- Author
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Keshavanath, P., Shivanna, and Gangadhara, B.
- Subjects
- *
ENERGY crops , *WATER quality , *WATER pollution , *WATER quality management - Abstract
Abstract: The effectiveness of pressmud, a sugarcane by-product, was tested as a manure in the production of natural food and carp, by conducting two experiments. The first experiment, of 5 weeks duration, examined the effect of pressmud addition on water quality and natural food production. This study was carried out in fibreglass tubs (1.54m3) with a 5cm mud layer, employing pressmud at dosages of 5000, 10,000 and 15,000kgha−1 for treatments T1, T2 and T3, respectively. Unfertilized tubs served as control (T0). The second experiment of 120-day duration to study the effect on growth, survival and quality of common carp was conducted in 25m2 cement tanks with 15cm-mud bottom, using the same dosages of pressmud. The control tanks in this experiment were manured with cattle dung at 10,000kgha−1 (T0). Application of pressmud enhanced (P <0.05) natural food production, with the greatest effect noted in treatment T3. Fish growth was significantly greater (P <0.05) in treatments T2 and T3, there being no difference in growth between the control (T0) and 5000kg pressmud treatment (T1). The greatest survival and production were obtained under treatment T2, which indicates that the dosage of 10,000 kgha−1 pressmud is optimal for carp culture. A significant effect (P <0.05) of pressmud on carcass protein was observed. Organoleptic quality of both raw flesh and cooked meat of carp was not affected (P >0.05) by pressmud treatment. [Copyright &y& Elsevier]
- Published
- 2006
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29. A Study on Effects of Telecom Electromagnetic Radiations on Eco-System of the Region using Geo-Information Technology.
- Author
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Naveenchandra, B., Lokesh, K. N., Usha, and Gangadhara, B. H.
- Subjects
- *
ELECTROMAGNETIC radiation , *RADIO frequency , *ELECTROMAGNETIC fields , *ECOSYSTEMS , *ELECTROMAGNETIC waves , *CELL phones , *ORGANIC compounds research - Abstract
Our environment is subjected to exposure to microwave and radio electromagnetic irradiations because of widespread use of wireless telecommunication services. The electromagnetic radiations like radio waves, microwaves and Infrared rays emitted from the multiple telecom sites also contributing large amounts of environment harming to natural eco systems and causing climate change. A potentially constant exposure has caused an alert in public and governments about the so-called environmental electromagnetic pollution. Assessment of the RF EMF impact on plants is of great importance because plants have an important role in the living world as main primary producers of organic compounds and oxygen. Plants are continuously exposed to various environmental stresses and display a wide spectrum of developmental and biochemical responses contributing to stress adaptation. Their physiological responses can be evoked by a great variety of external stimuli, including mobile phone radiation. The adverse effects of electromagnetic radiation from mobile phones and communication towers on health of human beings are well documented today. However, exact correlation between radiation of communication towers and eco-system, are not yet very well established. In this context, there is need to carry out the scientific investigations to understand the effects of RF radiation on plants. The main objective of this research is to measurement of signal strength and power emitted by the tower and to establish guidelines for limiting EMF exposure that will provide protection against blown adverse effects on ecosystems will be studied using Geo-Informatics techniques in Udupi District, Karnataka State. The advancement in the recent years in the field of Geo-Informatics has enabled us to get the required spatial information of the environment in a better way. [ABSTRACT FROM AUTHOR]
- Published
- 2015
30. Simultaneous surgical management of malignancy and coronary heart disease.
- Author
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Nandy K, Gangadhara B, Reddy S, Chakravarthy M, Jawali V, Thimmaiah SG, Khan A, and Nayak SP
- Abstract
Coronary heart disease and cancer are the most common causes of mortality across the globe. It has been a dilemma for the surgical team to decide which surgical procedure should be done first when a patient needs surgery for both. This is a single-center retrospective observational study. Six patients who underwent simultaneous coronary artery bypass graft (CABG) and oncological surgeries between January 2018 and July 2021 were included in the study. One patient underwent lung bilobectomy via the same sternotomy incision; one underwent surgery for breast cancer, stomach cancer, and colon cancer; and one patient each of buccal mucosa carcinoma and tongue carcinoma. The median age was 65 years (59-70). Median blood loss was 550 ml (400-800). The median intensive care unit (ICU) stay was 60 h (46-130) and hospital stay was 7.5 days (6-14). The median follow-up of the present study was 31.5 months (6-38). One patient with lung carcinoma developed recurrence after 6 months and the patient is in remission after a follow-up of 32 months. Simultaneous CABG and oncological resection can be performed effectively and safely by an experienced team of cardiothoracic surgeons, surgical oncologists, and anesthetists after good patient selection., Competing Interests: Competing interestsThe authors declare no competing interests., (© Indian Association of Cardiovascular-Thoracic Surgeons 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)
- Published
- 2024
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31. 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
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32. A vector finite element approach to temperature dependent parameters of microwave ablation for liver cancer.
- Author
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Gangadhara B and Mariappan P
- Subjects
- Humans, Temperature, Microwaves therapeutic use, Finite Element Analysis, Liver surgery, Liver Neoplasms surgery, Carcinoma, Hepatocellular surgery, Ablation Techniques methods
- Abstract
Microwave ablation (MWA) is a minimally invasive treatment for cancer that uses electromagnetic waves to kill the tumor cells without significantly damaging the surrounding healthy cells. A three-state cell death model calculates the thermal damage around the Hepatocellular carcinoma (HCC) tumor in the liver tissue. The temperature profile is simulated for a single-slot co-axial antenna with a 1 mm air slot located near the tip of the antenna to produce an adequate amount of heat. The aims of this study are (1) to use the vector/edge finite element method (VFEM) to simulate the electromagnetic wave propagation to obtain the specific absorption rate, which is an input for the bio-heat equation that predicts the heat distribution in the liver tissue during MWA treatment, and (2) to compare the computational costs of VFEM and the finite element method (FEM) when different types of input powers and dielectric properties are used in the wave propagation equation. This study claims that the accuracy level increases marginally with less computation cost while using VFEM for temperature-dependent wave propagation equation., (© 2022 John Wiley & Sons Ltd.)
- Published
- 2023
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33. 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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34. Robotic-assisted breast-axillo insufflation thyroidectomy (RABIT): a retrospective case series of thyroid carcinoma.
- Author
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Nayak SP, Sadhoo A, Gangadhara B, Reddy S, Khan A, Munisiddaiah D, and Ramakrishnan A
- Subjects
- Adult, Axilla surgery, Breast surgery, Female, Humans, Insufflation, Laryngoscopy, Length of Stay, Male, Middle Aged, Operative Time, Postoperative Complications etiology, Retrospective Studies, Robotic Surgical Procedures adverse effects, Robotic Surgical Procedures instrumentation, Thyroid Cancer, Papillary pathology, Thyroid Cancer, Papillary surgery, Thyroid Neoplasms pathology, Thyroidectomy adverse effects, Treatment Outcome, Robotic Surgical Procedures methods, Thyroid Neoplasms surgery, Thyroidectomy methods
- Abstract
Objective: To evaluate the feasibility and safety of robotic-assisted breast-axillo insufflation thyroidectomy (RABIT) for differentiated thyroid cancer., Methods: In this retrospective case series, patients with differentiated thyroid carcinoma were enrolled in our hospital from January 2018 to December 2018. All patients underwent indirect laryngoscopy to assess the status of vocal cord preoperatively. RABIT was performed with five separate breast-axillo incisions. All the procedures were performed using da Vinci Xi Robotic Surgical System, a single docking method using CO
2 insufflation., Results: Twelve patients completed RABIT, in which one case needed conversion to open thyroidectomy. The mean age was 30.25 ± 7 with male to female ratio being 1:1. Preoperative diagnosis showed papillary carcinoma (n = 9) and follicular neoplasm (n = 3). The mean operative time for RABIT was 140 ± 50.45 min and average blood loss during surgery was 22.92 ± 9 mL. Mean hospital stay was 4.42 ± 1.08 days. Final pathology confirmed classical papillary thyroid carcinoma (n = 10; 83.3%) and follicular variant of papillary carcinoma (n = 2; 16.7%). None of the cases reported injury or paralysis to the recurrent laryngeal nerves., Conclusion: RABIT is a safe and feasible approach for thyroidectomy. It has several advantages in that it provides similar symmetrical view to conventional open surgery and enables to maintain specimen integrity and use of assistant port permits better handling of the gland. Additionally, the largest operating angles with this technique prevent collision between the robotic arms and provide excellent cosmetic satisfaction due to very small, five separate breast-axillo incisions.- Published
- 2020
- Full Text
- View/download PDF
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