Vijayakrishna Rapaka - Academia.edu (original) (raw)

Papers by Vijayakrishna Rapaka

International journal of engineering research and technology, Jul 17, 2013

The search for renewable sources of energy resulted in the revival of a concept "Ocean Thermal En... more The search for renewable sources of energy resulted in the revival of a concept "Ocean Thermal Energy Conversion" which utilizes the difference in temperature between the warm tropical surface waters and the cold deep ocean water available at depths of about 1000 m operating in a Rankine cycle. The heat exchangers are the major components of the OTEC power plants and they play an important role in the economy of the OTEC power plants, hence a proper selection of materials, design criteria, working fluid and working conditions for the heat exchangers are necessary for an energy efficient and techno-economically feasible OTEC power plant. The following parameters: pipe length, pipe diameter, seawater depth and the flow rate of seawater were considered. The theoretical investigations revealed that a maximum output of the net work exists at a certain flow rate of cooling seawater. In this report, the design of heat exchanger for a 0.1 MWe OTEC power plant is carried out and the performance of the heat exchanger for varying depths, for varying velocities of the intake fluid, for varying mass fraction of the working fluid, for varying length of the plates is simulated using Engineering Equations Solver. In addition, the variation in the Reynolds number, Nusselt number, Pressure drop and Overall heat transfer coefficient for varied process conditions are estimated and presented in graphical form.

In a previous publication, the use o f a sim ple two dimensional finite difference m odel to pred... more In a previous publication, the use o f a sim ple two dimensional finite difference m odel to predict hydrogen distribution in a sim ulated part w all pipeline girth w eld repair was dem onstrated. The validity o f the model prediction was assessed using slow bend tests where the deflection to failure was an indirect indicator o f the local bulk hydrogen concentration at the critical site for delayed cracking. In the present investigation, the sam e hydrogen diffusion m odel has been used to predict the m axim um tim e for delayed cracking in a sim ulated girth w eld repair for two am bient temperatures, (20° and-10°C). These predictions are com pared w ith the delayed cracking times in "constant deflection" tests perform ed at the selected am bient temperatures. The results obtained show ed that there was some scatter in the relationship betw een the experim entally applied deflections and the delay tim e to crack initiation. The delay time predicted by the m odel for the local hydrogen concentration to reach its m axim um value at the crack initiation site, how ever, was a function o f the am bient temperature and these agreed reasonably w ell w ith the m axim um delay times to cracking observed in the experiments. BACKGROUND AND OBJECTIVE Considerable research has been perform ed over the years and techniques developed to m itigate delayed hydrogen induced cracking in single pass welds. Such delays are

Ocean Engineering, Apr 1, 2004

ABSTRACT This paper attempts to provide a better understanding of the hydrodynamic behaviour of a... more ABSTRACT This paper attempts to provide a better understanding of the hydrodynamic behaviour of a floating multi-resonant oscillating column wave energy device which combines the concept of a floating breakwater and a wave energy device. Experiments were conducted on a 1:20 scale model of the floating wave energy device moored by six mooring lines to study the dynamics of the device under regular waves for various scopes. The effect of non-dimensionalized wave frequency parameter on the motion response and mooring force are reported and discussed in detail in this paper.

A discontinuous thread is one, which is normally made for lug finishes as seen in jam jar bottles... more A discontinuous thread is one, which is normally made for lug finishes as seen in jam jar bottles and other food products, bottles that are usually filled under vacuum. The current practice of machining the threads in the die for lug finish is done manually. This increases the lead-time and the quality of lug finish is very poor. In order to reduce the lead time and to improve the quality of the lug finish in the components, a novel method using a special type of milling attachment along with an indexing mechanism has been developed to machine the discontinuous threads. This paper explains clearly the fabrication details and the working mechanism of a model of the special type of fixture used for milling discontinuous threads.

Tunnelling and Underground Space Technology, 2004

The shortage of oil in many parts of the world and the increase in the price of this commodity ha... more The shortage of oil in many parts of the world and the increase in the price of this commodity had led to the new era of renewable resources. The need for developing energy alternatives in order to conserve energy in thus evident and considerable research and development work is already in progress in this direction. In this paper, the thermal design of a solar pond has been carried out in a Dairy Industry located at Pondicherry, India (Latitude 11.56 ON, Longitude 79.53 OE) in order to replace the existing boiler, which is being used for the supply of hot water to the Pasteurizer unit at a temperature of 80 OC. The thermal efficiency of the pond has been worked out using correlation proposed by Kooi and Hull. Theoretical temperature profiles and optimum thickness of NCZ has been calculated based on the correlation developed by Kooi. The fuel savings by eliminating the usage of boiler for supplying hot water to the Pasteurizer unit is found to be around 38,000 litres per year.

Applied Mechanics and Materials, Jul 1, 2014

The solar Gel pond is an innovative concept which overcomes many of the shortcomings of the conve... more The solar Gel pond is an innovative concept which overcomes many of the shortcomings of the conventional gradient solar pond. The non-convective salt gradient layer is replaced by a transparent polymer gel layer, which floats on a NaCl solution (Sea water) used in the storage zone. The polymer gel (Carbowax) used was found to be insoluble in different concentration of NaCl solution with good transmissivity characteristics. An attempt has been made to analyse the performance of the solar gel pond of 0.25 m 2 area at Pondicherry, India (Latitude 11.56 o N & Longitudinal 79.53 o E). Experimental investigation has been carried out during the month of February, March and May 2004. The maximum storage temperature was found to be 60 o C and temperature difference between the storage layer and gel layer was found to be around 10 o C. The outcome of the experimental investigations has been reported in this paper.

International Journal of Innovative Research in Science, Engineering and Technology, 2013

The solar Gel pond is an innovative concept which overcomes many of the shortcomings of the conve... more The solar Gel pond is an innovative concept which overcomes many of the shortcomings of the conventional gradient solar pond. The non-convective salt gradient layer is replaced by a transparent polymer gel layer, which floats on a NaCl solution (Sea water) used in the storage zone. The polymer gel (Carbowax) used was found to be insoluble in different concentration of NaCl solution with good transmissivity characteristics. An attempt has been made to analyse the performance of the solar gel pond of 0.25 m 2 area at Pondicherry, India (Latitude 11.56 o N & Longitudinal 79.53 o E). Experimental investigation has been carried out during the month of February, March and May 2004. The maximum storage temperature was found to be 60 o C and temperature difference between the storage layer and gel layer was found to be around 10 o C. The outcome of the experimental investigations has been reported in this paper.

2023 5th International Conference on Smart Systems and Inventive Technology (ICSSIT)

2022 International Conference on Automation, Computing and Renewable Systems (ICACRS)

2022 International Conference on Automation, Computing and Renewable Systems (ICACRS)

2022 International Conference on Augmented Intelligence and Sustainable Systems (ICAISS)

Barth and Schlegelmilch (2013), explain that, in scientific theory, the term academic entrepreneu... more Barth and Schlegelmilch (2013), explain that, in scientific theory, the term academic entrepreneurship is defined and developed in different ways. From the traditional perspective academic entrepreneurship means an ―university spin-off‖ or an institutional transfer of research, development, or technology to start innovations or ventures. The purpose of this paper is to review and synthesize the literature on the various challenges and opportunities in Academic Entrepreneurship. Although education and research have traditionally been the university‗s main missions, this has gradually changed with the emergence of new perspectives on the role of the university in the system of intellectual property generation, production, sharing and distribution (Nyeko & Sing, 2015). Silva (2012) argues that 3rd university mission involving academic entrepreneurship, opens the possibility for many higher education institutions to get a broader source of funding from non-governmental or public organizations. The adaption and adoption of ―entrepreneurial flair into the university appears to create discontent among academics to whom the concept of entrepreneurship implies the creation of a new venture and income generation. This paper highlights the features of academic entrepreneur and academic entrepreneurship while the center of focus being the challenges and opportunities faced in academic entrepreneurship.

Abstract: The search for renewable sources of energy resulted in the revival of a concept based o... more Abstract: The search for renewable sources of energy resulted in the revival of a concept based on the utilization of the differences in temperature between the warm tropical surface waters and the cold deep ocean water available at depths of about 1000 m as the source of the thermal energy required to vaporize and condense the working fluid of a turbinegenerator system respectively. This concept is referred to as "Ocean Thermal Energy Conversion". As the temperature in the top surface is equal to the ambient temperature and the temperature in the bottom surface is much cooler when compared to the top surface, there exists a temperature difference between the layers of the ocean and this temperature difference is utilized to run an OTEC power plant. In this work, simulation of the OTEC power plant is done to optimize the specific power output by varying the intake velocities and depth. Ammonia is used as the working fluid. The maximum specific power output is obtained for ...

A detailed experimental investigation conducted on a moored Oscillating Water Column (OWC) wave e... more A detailed experimental investigation conducted on a moored Oscillating Water Column (OWC) wave energy device has been reported in this paper. The experiments were conducted on 1:20 scale model of the wave energy device, which was moored to the bed using 6 mooring lines in a 2m wide (deep and shallow water) wave flume at Ocean Engineering Department, IITM, Chennai. A range of hydrodynamic parameters with different damping ratio of the OWC chamber at scope 4 (length of the mooring line/depth of water) for a constant water depth was used. The effect of nondimensionalized parameters like non-dimensionlized wave frequency parameter (ω 2 B/2g) and device breadth to wave length ratio (B/L) on the mooring force and on the efficiency of the wave energy device has been studied. The motion responses and mooring forces were measured and the test results are analysed and presented with discussions in this paper.

Abstract: The search for renewable sources of energy resulted in the revival of a concept based o... more Abstract: The search for renewable sources of energy resulted in the revival of a concept based on the utilization of the differences in temperature between the warm tropical surface waters and the cold deep ocean water available at depths of about 1000 m as the source of the thermal energy required to vaporize and condense the working fluid of a turbinegenerator system respectively. This concept is referred to as "Ocean Thermal Energy Conversion". As the temperature in the top surface is equal to the ambient temperature and the temperature in the bottom surface is much cooler when compared to the top surface, there exists a temperature difference between the layers of the ocean and this temperature difference is utilized to run an OTEC power plant. In this work, simulation of the OTEC power plant is done to optimize the specific power output by varying the intake velocities and depth. Ammonia is used as the working fluid. The maximum specific power output is obtained for ...

Electrochimica Acta, 2021

Supercapacitors are considered to be promising energy storage devices because of their long cycle... more Supercapacitors are considered to be promising energy storage devices because of their long cycle stability, fast charge-discharge, and high power density. However, energy storage performance predominantly depends on the morphology and nanostructure of electrode materials. The material with porous nanostructures has attracted great interest because of more active sites for the faradaic reactions which facilitate the utilization of the full capacity of the active materials. Herein, porous CuCo2O4 (CCO) nanorods dispersed on reduced graphene oxide (rGO) nanosheets (CCO/rGO) has been prepared in a short duration via a facile single-step microwave hydrothermal method. The porous feature of the CCO nanorod provides more reactive sites for faradaic reaction and facilitates the electrolyte penetration into the inner region of the electrode. Also, the incorporation of rGO provides a more conductive network that facilitates the collection and transportation of electrons during cycling. Elect...

The search for renewable sources of energy resulted in the revival of a concept “Ocean Thermal En... more The search for renewable sources of energy resulted in the revival of a concept “Ocean Thermal Energy Conversion” which utilizes the difference in temperature between the warm tropical surface waters and the cold deep ocean water available at depths of about 1000 m operating in a Rankine cycle. The heat exchangers are the major components of the OTEC power plants and they play an important role in the economy of the OTEC power plants, hence a proper selection of materials, design criteria, working fluid and working conditions for the heat exchangers are necessary for an energy efficient and techno-economically feasible OTEC power plant. The following parameters: pipe length, pipe diameter, seawater depth and the flow rate of seawater were considered. The theoretical investigations revealed that a maximum output of the net work exists at a certain flow rate of cooling seawater. In this report, the design of heat exchanger for a 0.1 MWe OTEC power plant is carried out and the performa...

Abstract: The search for renewable sources of energy resulted in the revival of a concept based o... more Abstract: The search for renewable sources of energy resulted in the revival of a concept based on the utilization of the differences in temperature between the warm tropical surface waters and the cold deep ocean water available at depths of about 1000 m as the source of the thermal energy required to vaporize and condense the working fluid of a turbine generator system respectively. This concept is referred to as “Ocean Thermal Energy Conversion”. As the temperature in the top surface is equal to the ambient temperature and the temperature in the bottom surface is much cooler when compared to the top surface, there exists a temperature difference between the layers of the ocean and this temperature difference is utilized to run an OTEC power plant. In this work, simulation of the OTEC power plant is done to optimize the specific power output by varying the intake velocities and depth. Ammonia is used as the working fluid. The maximum specific power output is obtained for a depth o...

International Journal of Innovative Research in Science, Engineering and Technology, 2013

The solar Gel pond is an innovative concept which overcomes many of the shortcomings of the conve... more The solar Gel pond is an innovative concept which overcomes many of the shortcomings of the conventional gradient solar pond. The non- convective salt gradient layer is replaced by a transparent polymer gel layer, which floats on a NaCl solution (Sea water) used in the storage zone. The polymer gel (Carbowax) used was found to be insoluble in different concentration of NaCl solution with good transmissivity characteristics. An attempt has been made to analyse the performance of the solar gel pond of 0.25 m2 area at Pondicherry, India (Latitude 11.56o N & Longitudinal 79.53o E). Experimental investigation has been carried out during the month of February, March and May 2004. The maximum storage temperature was found to be 60 oC and temperature difference between the storage layer and gel layer was found to be around 10 oC. The outcome of the experimental investigations has been reported in this paper.

A discontinuous thread is one, which is normally made for lug finishes as seen in jam jar bottles... more A discontinuous thread is one, which is normally made for lug finishes as seen in jam jar bottles and other food products, bottles that are usually filled under vacuum. The current practice of machining the threads in the die for lug finish is done manually. This increases the lead-time and the quality of lug finish is very poor. In order to reduce the lead time and to improve the quality of the lug finish in the components, a novel method using a special type of milling attachment along with an indexing mechanism has been developed to machine the discontinuous threads. This paper explains clearly the fabrication details and the working mechanism of a model of the special type of fixture used for milling discontinuous threads.

International journal of engineering research and technology, Jul 17, 2013

The search for renewable sources of energy resulted in the revival of a concept "Ocean Thermal En... more The search for renewable sources of energy resulted in the revival of a concept "Ocean Thermal Energy Conversion" which utilizes the difference in temperature between the warm tropical surface waters and the cold deep ocean water available at depths of about 1000 m operating in a Rankine cycle. The heat exchangers are the major components of the OTEC power plants and they play an important role in the economy of the OTEC power plants, hence a proper selection of materials, design criteria, working fluid and working conditions for the heat exchangers are necessary for an energy efficient and techno-economically feasible OTEC power plant. The following parameters: pipe length, pipe diameter, seawater depth and the flow rate of seawater were considered. The theoretical investigations revealed that a maximum output of the net work exists at a certain flow rate of cooling seawater. In this report, the design of heat exchanger for a 0.1 MWe OTEC power plant is carried out and the performance of the heat exchanger for varying depths, for varying velocities of the intake fluid, for varying mass fraction of the working fluid, for varying length of the plates is simulated using Engineering Equations Solver. In addition, the variation in the Reynolds number, Nusselt number, Pressure drop and Overall heat transfer coefficient for varied process conditions are estimated and presented in graphical form.

In a previous publication, the use o f a sim ple two dimensional finite difference m odel to pred... more In a previous publication, the use o f a sim ple two dimensional finite difference m odel to predict hydrogen distribution in a sim ulated part w all pipeline girth w eld repair was dem onstrated. The validity o f the model prediction was assessed using slow bend tests where the deflection to failure was an indirect indicator o f the local bulk hydrogen concentration at the critical site for delayed cracking. In the present investigation, the sam e hydrogen diffusion m odel has been used to predict the m axim um tim e for delayed cracking in a sim ulated girth w eld repair for two am bient temperatures, (20° and-10°C). These predictions are com pared w ith the delayed cracking times in "constant deflection" tests perform ed at the selected am bient temperatures. The results obtained show ed that there was some scatter in the relationship betw een the experim entally applied deflections and the delay tim e to crack initiation. The delay time predicted by the m odel for the local hydrogen concentration to reach its m axim um value at the crack initiation site, how ever, was a function o f the am bient temperature and these agreed reasonably w ell w ith the m axim um delay times to cracking observed in the experiments. BACKGROUND AND OBJECTIVE Considerable research has been perform ed over the years and techniques developed to m itigate delayed hydrogen induced cracking in single pass welds. Such delays are

Ocean Engineering, Apr 1, 2004

ABSTRACT This paper attempts to provide a better understanding of the hydrodynamic behaviour of a... more ABSTRACT This paper attempts to provide a better understanding of the hydrodynamic behaviour of a floating multi-resonant oscillating column wave energy device which combines the concept of a floating breakwater and a wave energy device. Experiments were conducted on a 1:20 scale model of the floating wave energy device moored by six mooring lines to study the dynamics of the device under regular waves for various scopes. The effect of non-dimensionalized wave frequency parameter on the motion response and mooring force are reported and discussed in detail in this paper.

A discontinuous thread is one, which is normally made for lug finishes as seen in jam jar bottles... more A discontinuous thread is one, which is normally made for lug finishes as seen in jam jar bottles and other food products, bottles that are usually filled under vacuum. The current practice of machining the threads in the die for lug finish is done manually. This increases the lead-time and the quality of lug finish is very poor. In order to reduce the lead time and to improve the quality of the lug finish in the components, a novel method using a special type of milling attachment along with an indexing mechanism has been developed to machine the discontinuous threads. This paper explains clearly the fabrication details and the working mechanism of a model of the special type of fixture used for milling discontinuous threads.

Tunnelling and Underground Space Technology, 2004

The shortage of oil in many parts of the world and the increase in the price of this commodity ha... more The shortage of oil in many parts of the world and the increase in the price of this commodity had led to the new era of renewable resources. The need for developing energy alternatives in order to conserve energy in thus evident and considerable research and development work is already in progress in this direction. In this paper, the thermal design of a solar pond has been carried out in a Dairy Industry located at Pondicherry, India (Latitude 11.56 ON, Longitude 79.53 OE) in order to replace the existing boiler, which is being used for the supply of hot water to the Pasteurizer unit at a temperature of 80 OC. The thermal efficiency of the pond has been worked out using correlation proposed by Kooi and Hull. Theoretical temperature profiles and optimum thickness of NCZ has been calculated based on the correlation developed by Kooi. The fuel savings by eliminating the usage of boiler for supplying hot water to the Pasteurizer unit is found to be around 38,000 litres per year.

Applied Mechanics and Materials, Jul 1, 2014

The solar Gel pond is an innovative concept which overcomes many of the shortcomings of the conve... more The solar Gel pond is an innovative concept which overcomes many of the shortcomings of the conventional gradient solar pond. The non-convective salt gradient layer is replaced by a transparent polymer gel layer, which floats on a NaCl solution (Sea water) used in the storage zone. The polymer gel (Carbowax) used was found to be insoluble in different concentration of NaCl solution with good transmissivity characteristics. An attempt has been made to analyse the performance of the solar gel pond of 0.25 m 2 area at Pondicherry, India (Latitude 11.56 o N & Longitudinal 79.53 o E). Experimental investigation has been carried out during the month of February, March and May 2004. The maximum storage temperature was found to be 60 o C and temperature difference between the storage layer and gel layer was found to be around 10 o C. The outcome of the experimental investigations has been reported in this paper.

International Journal of Innovative Research in Science, Engineering and Technology, 2013

The solar Gel pond is an innovative concept which overcomes many of the shortcomings of the conve... more The solar Gel pond is an innovative concept which overcomes many of the shortcomings of the conventional gradient solar pond. The non-convective salt gradient layer is replaced by a transparent polymer gel layer, which floats on a NaCl solution (Sea water) used in the storage zone. The polymer gel (Carbowax) used was found to be insoluble in different concentration of NaCl solution with good transmissivity characteristics. An attempt has been made to analyse the performance of the solar gel pond of 0.25 m 2 area at Pondicherry, India (Latitude 11.56 o N & Longitudinal 79.53 o E). Experimental investigation has been carried out during the month of February, March and May 2004. The maximum storage temperature was found to be 60 o C and temperature difference between the storage layer and gel layer was found to be around 10 o C. The outcome of the experimental investigations has been reported in this paper.

2023 5th International Conference on Smart Systems and Inventive Technology (ICSSIT)

2022 International Conference on Automation, Computing and Renewable Systems (ICACRS)

2022 International Conference on Automation, Computing and Renewable Systems (ICACRS)

2022 International Conference on Augmented Intelligence and Sustainable Systems (ICAISS)

Barth and Schlegelmilch (2013), explain that, in scientific theory, the term academic entrepreneu... more Barth and Schlegelmilch (2013), explain that, in scientific theory, the term academic entrepreneurship is defined and developed in different ways. From the traditional perspective academic entrepreneurship means an ―university spin-off‖ or an institutional transfer of research, development, or technology to start innovations or ventures. The purpose of this paper is to review and synthesize the literature on the various challenges and opportunities in Academic Entrepreneurship. Although education and research have traditionally been the university‗s main missions, this has gradually changed with the emergence of new perspectives on the role of the university in the system of intellectual property generation, production, sharing and distribution (Nyeko & Sing, 2015). Silva (2012) argues that 3rd university mission involving academic entrepreneurship, opens the possibility for many higher education institutions to get a broader source of funding from non-governmental or public organizations. The adaption and adoption of ―entrepreneurial flair into the university appears to create discontent among academics to whom the concept of entrepreneurship implies the creation of a new venture and income generation. This paper highlights the features of academic entrepreneur and academic entrepreneurship while the center of focus being the challenges and opportunities faced in academic entrepreneurship.

Abstract: The search for renewable sources of energy resulted in the revival of a concept based o... more Abstract: The search for renewable sources of energy resulted in the revival of a concept based on the utilization of the differences in temperature between the warm tropical surface waters and the cold deep ocean water available at depths of about 1000 m as the source of the thermal energy required to vaporize and condense the working fluid of a turbinegenerator system respectively. This concept is referred to as "Ocean Thermal Energy Conversion". As the temperature in the top surface is equal to the ambient temperature and the temperature in the bottom surface is much cooler when compared to the top surface, there exists a temperature difference between the layers of the ocean and this temperature difference is utilized to run an OTEC power plant. In this work, simulation of the OTEC power plant is done to optimize the specific power output by varying the intake velocities and depth. Ammonia is used as the working fluid. The maximum specific power output is obtained for ...

A detailed experimental investigation conducted on a moored Oscillating Water Column (OWC) wave e... more A detailed experimental investigation conducted on a moored Oscillating Water Column (OWC) wave energy device has been reported in this paper. The experiments were conducted on 1:20 scale model of the wave energy device, which was moored to the bed using 6 mooring lines in a 2m wide (deep and shallow water) wave flume at Ocean Engineering Department, IITM, Chennai. A range of hydrodynamic parameters with different damping ratio of the OWC chamber at scope 4 (length of the mooring line/depth of water) for a constant water depth was used. The effect of nondimensionalized parameters like non-dimensionlized wave frequency parameter (ω 2 B/2g) and device breadth to wave length ratio (B/L) on the mooring force and on the efficiency of the wave energy device has been studied. The motion responses and mooring forces were measured and the test results are analysed and presented with discussions in this paper.

Abstract: The search for renewable sources of energy resulted in the revival of a concept based o... more Abstract: The search for renewable sources of energy resulted in the revival of a concept based on the utilization of the differences in temperature between the warm tropical surface waters and the cold deep ocean water available at depths of about 1000 m as the source of the thermal energy required to vaporize and condense the working fluid of a turbinegenerator system respectively. This concept is referred to as "Ocean Thermal Energy Conversion". As the temperature in the top surface is equal to the ambient temperature and the temperature in the bottom surface is much cooler when compared to the top surface, there exists a temperature difference between the layers of the ocean and this temperature difference is utilized to run an OTEC power plant. In this work, simulation of the OTEC power plant is done to optimize the specific power output by varying the intake velocities and depth. Ammonia is used as the working fluid. The maximum specific power output is obtained for ...

Electrochimica Acta, 2021

Supercapacitors are considered to be promising energy storage devices because of their long cycle... more Supercapacitors are considered to be promising energy storage devices because of their long cycle stability, fast charge-discharge, and high power density. However, energy storage performance predominantly depends on the morphology and nanostructure of electrode materials. The material with porous nanostructures has attracted great interest because of more active sites for the faradaic reactions which facilitate the utilization of the full capacity of the active materials. Herein, porous CuCo2O4 (CCO) nanorods dispersed on reduced graphene oxide (rGO) nanosheets (CCO/rGO) has been prepared in a short duration via a facile single-step microwave hydrothermal method. The porous feature of the CCO nanorod provides more reactive sites for faradaic reaction and facilitates the electrolyte penetration into the inner region of the electrode. Also, the incorporation of rGO provides a more conductive network that facilitates the collection and transportation of electrons during cycling. Elect...

The search for renewable sources of energy resulted in the revival of a concept “Ocean Thermal En... more The search for renewable sources of energy resulted in the revival of a concept “Ocean Thermal Energy Conversion” which utilizes the difference in temperature between the warm tropical surface waters and the cold deep ocean water available at depths of about 1000 m operating in a Rankine cycle. The heat exchangers are the major components of the OTEC power plants and they play an important role in the economy of the OTEC power plants, hence a proper selection of materials, design criteria, working fluid and working conditions for the heat exchangers are necessary for an energy efficient and techno-economically feasible OTEC power plant. The following parameters: pipe length, pipe diameter, seawater depth and the flow rate of seawater were considered. The theoretical investigations revealed that a maximum output of the net work exists at a certain flow rate of cooling seawater. In this report, the design of heat exchanger for a 0.1 MWe OTEC power plant is carried out and the performa...

Abstract: The search for renewable sources of energy resulted in the revival of a concept based o... more Abstract: The search for renewable sources of energy resulted in the revival of a concept based on the utilization of the differences in temperature between the warm tropical surface waters and the cold deep ocean water available at depths of about 1000 m as the source of the thermal energy required to vaporize and condense the working fluid of a turbine generator system respectively. This concept is referred to as “Ocean Thermal Energy Conversion”. As the temperature in the top surface is equal to the ambient temperature and the temperature in the bottom surface is much cooler when compared to the top surface, there exists a temperature difference between the layers of the ocean and this temperature difference is utilized to run an OTEC power plant. In this work, simulation of the OTEC power plant is done to optimize the specific power output by varying the intake velocities and depth. Ammonia is used as the working fluid. The maximum specific power output is obtained for a depth o...

International Journal of Innovative Research in Science, Engineering and Technology, 2013

The solar Gel pond is an innovative concept which overcomes many of the shortcomings of the conve... more The solar Gel pond is an innovative concept which overcomes many of the shortcomings of the conventional gradient solar pond. The non- convective salt gradient layer is replaced by a transparent polymer gel layer, which floats on a NaCl solution (Sea water) used in the storage zone. The polymer gel (Carbowax) used was found to be insoluble in different concentration of NaCl solution with good transmissivity characteristics. An attempt has been made to analyse the performance of the solar gel pond of 0.25 m2 area at Pondicherry, India (Latitude 11.56o N & Longitudinal 79.53o E). Experimental investigation has been carried out during the month of February, March and May 2004. The maximum storage temperature was found to be 60 oC and temperature difference between the storage layer and gel layer was found to be around 10 oC. The outcome of the experimental investigations has been reported in this paper.

A discontinuous thread is one, which is normally made for lug finishes as seen in jam jar bottles... more A discontinuous thread is one, which is normally made for lug finishes as seen in jam jar bottles and other food products, bottles that are usually filled under vacuum. The current practice of machining the threads in the die for lug finish is done manually. This increases the lead-time and the quality of lug finish is very poor. In order to reduce the lead time and to improve the quality of the lug finish in the components, a novel method using a special type of milling attachment along with an indexing mechanism has been developed to machine the discontinuous threads. This paper explains clearly the fabrication details and the working mechanism of a model of the special type of fixture used for milling discontinuous threads.