Learning and Analytics in Intelligent Systems, 2019
In an advanced electrical power system, a wide range of loads used by industrial, domestic, irrig... more In an advanced electrical power system, a wide range of loads used by industrial, domestic, irrigation, traction loads, commercial applications, advanced machinery of different electrical drives, control systems, and proliferation of different electronic gadgets day to day life, road, rail transport systems etc., have a greater impact on power quality. Another power quality issue is due to lesser power generating capacity of existing conventional resources and the combined operation of non-conventional energy resources into the power systems as hybrid electrical power generating systems. In this paper to decrease the gap between electrical power generation and demand added proton exchange membrane fuel cell as a hybrid electrical power system and addressed different power quality issues arise in power systems due to different loading conditions, impact of the tower shadowing effect of wind energy system in a weak grid system. A power electronics device: UPQC build up with instantaneous power theory to address these power quality issues within international standards.
To prevent the illegal copying and sharing of digital content, the need for security for digital ... more To prevent the illegal copying and sharing of digital content, the need for security for digital data is highly demanded. Among various available techniques, digital watermarking is an effective solution to protect confidential data. This paper presents the performance analysis of color image watermarking based on lifting scheme in which color image watermark has been used. Peak signal-to-noise ratio (PSNR), Structural similarity (SSIM) index and normalized correlation coefficient (NCC), etc. have been used as fidelity parameters to test the effectiveness of presented work both quantitatively and qualitatively.
The world celebrates over 50 years since the first human-to-human heart transplant. Bibliometric ... more The world celebrates over 50 years since the first human-to-human heart transplant. Bibliometric analysis is a statistical concept that has recently evolved, enabling scientists to study citation patterns and identify characteristics of highly cited scholarly work in different fields. Although it has been widely utilized, such analyses have not been conducted to date on heart transplant literature. We sought to assess the characteristics of the top 100 most referenced citations in the field of heart transplantation. We searched the Scopus database (www.scopus.com) to identify all articles relating to heart transplantation. The articles were arranged in descending order from most cited to least cited and selected articles were scrutinized for data extraction. One hundred articles were included in the final list. Of the total 40,660 citations identified, 3,210 (8.0%) were self-citations, which impacted the final rank order. The articles were published in 25 different journals between 1960 and 2013. The most productive 5-year time period was between 2000 and 2005, when 24 of the 100 most cited publications were produced. There was no correlation between the journals' impact factors and the number of articles produced per journal. The presence and type of funding were not associated with the number of citations. Over 85% of first and senior investigators were men. In conclusion, our study highlights key features of the most highly cited scientific literature on heart transplantation and provides insights into trends of published work in this field. Additionally, this work may serve as a useful guide to researchers and funding bodies by highlighting the most prolific areas of cardiac transplant research to date.
Mosquitoes transmit serious human diseases, causing millions of deaths every year. The use of syn... more Mosquitoes transmit serious human diseases, causing millions of deaths every year. The use of synthetic insecticides to control vector mosquitoes has caused physiological resistance and adverse environmental effects in addition to high operational cost. Insecticides of synthesized natural products for vector control have been a priority in this area. In the present study, silver nanoparticles (AgNPs) synthesized using Cassia roxburghii plant leaf extract against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus were determined. Larvae were exposed to varying concentrations of synthesized AgNPs (12, 24, 36, 48, and 60 μg/mL) and aqueous leaf extracts (60, 120, 180, 240, and 300 μg/mL) for 24 h. The synthesized AgNPs were characterized by UV-Vis spectrum, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), with energy-dispersive X-ray spectroscopy analysis (EDX), transmission electron microscopy, and X-ray diffraction analysis (XRD). Compare to aqueous extracted synthesized AgNPs showed extensive mortality rate against An. stephensi, Ae. aegypti, and C. quinquefasciatus with the LC50 and LC90 values that were 26.35, 28.67, 31.27 and 48.81, 53.24, and 58.11 μg/mL, respectively. No mortality was observed in the control. This is the first report on mosquito larvicidal activity of plant-synthesized nanoparticles. Thus, the use of C. roxburghii to synthesize silver nanoparticles is a rapid, eco-friendly, and a single-step approach, and the AgNPs formed can be potential mosquito larvicidal agents. Therefore, this study proves that C. roxburghii is a potential bioresource for stable, reproducible nanoparticle synthesis (AgNPs) and also can be used as an efficient mosquito control agent. This is the first report on the larvicidal activity of the plant extract and AgNPs.
In the present study an attempt was made to control the microstructure evolution during extrusion... more In the present study an attempt was made to control the microstructure evolution during extrusion using the NARMA_L2 Control approach with Neural Networks. The final grain size after extrusion was considered as the optimal criterion and the grain size was expressed in terms of strain, strain rate and temperature. The steps involved in NARMA _L2 Control approach include process modelling, system identification and controller design. The trajectories of the independent variables to achieve the desired grain size were obtained and the strain values were further utilized to optimize the dimensions of the extrusion die profile to achieve the required grain size.
Structure-controlled synthesis of gold nanostructures (AuNSs) induced by temperature in a nonaque... more Structure-controlled synthesis of gold nanostructures (AuNSs) induced by temperature in a nonaqueous urea–choline chloride deep eutectic solvent (DES) is reported.
In this study, Leucas aspera whole plant methanolic extract were examined for their phytochemical... more In this study, Leucas aspera whole plant methanolic extract were examined for their phytochemical profile by high-performance thin layer chromatographic (HTPLC) method. Alkaloids, Steroids and Flavonoids profile were analysed. Our results revealed that at least two types of alkaloids were seen in this methanolic extracts. Six types of flavonoids and two types of steroids were found in the Leucas aspera whole plant methanolic extract. Alkaloid and flavonoid were found to have higher concentration when compared to steroids which were in lower concentration in the methanolic extract.
Modeling and simulation provide objective analysis tools for many fields including manufacturing.... more Modeling and simulation provide objective analysis tools for many fields including manufacturing. This paper presents the requirements and describes the usefulness of a web-based interface to discrete-event simulation. A description of related efforts is first presented and an approach is then described. The approach develops a webbased interface to use commercial discrete-event commercial tools.
Protease producing halotolerant bacterium was isolated from saltern pond sediment (Tuticorin) and... more Protease producing halotolerant bacterium was isolated from saltern pond sediment (Tuticorin) and identified as Bacillus licheniformis (TD4) by 16S rRNA gene sequencing. Protease production was enhanced by optimizing the culture conditions. The nutritional factors such as carbon and nitrogen sources, NaCl and also physical parameters like incubation time, pH, agitation, inoculum size were optimized for the maximum yield of protease. Studies on the effect of different carbon and nitrogen sources revealed that xylose and urea enhances the enzyme production. Thus, with selected C-N sources along with 1 M NaCl the maximum protease production (141.46 U/mg) was obtained in the period of 24 h incubation at pH 8 under 250 rpm compared to the initial enzyme production (89.87 U/mg).
Mahseer are popularly regarded by anglers as the king of freshwater fishes, and are valued across... more Mahseer are popularly regarded by anglers as the king of freshwater fishes, and are valued across the Himalayan and South-east Asian regions. In India, mahseer are important game fish. Mahseer populations and their habitats face a range of anthropogenic threats, however, including unregulated fishing and habitat fragmentation as a result of hydro-development projects. Catch-and-release angling for mahseer attracts both national and international anglers and could provide information about rivers while generating revenue for regional economies. In this context, we evaluated catch-and-release angling records from rivers that flow within two Indian reserves (the Ramganga and Jia Bharali Rivers in Corbett and Nameri Tiger Reserves, respectively). Golden mahseer Tor putitora in the Ramganga and golden and chocolate mahseer Neolissochilus hexagonolepis in the Jia Bharali were the most frequently caught fish species. Catch data suggested these game fish populations are probably not negativ...
Silicon carbide reinforced aluminium composite materials are increasingly used in many engineerin... more Silicon carbide reinforced aluminium composite materials are increasingly used in many engineering fields. Flow stress prediction for these materials is increasingly important. In the present work, flow stress of 1.0Mg-0.6% Si-0.3% Cu-0.2% Cr rest Al with 15% SiC p during hot deformation is carried out using the conventional regression method, artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) method. The temperature at which the aluminium is compressed are 300-500°C with strain rates ranging from 0.00857 to 2.7 s À1 and for the strains of 0.1-0.5. Simulation studies are carried out for analysis. By comparing the performances of various modeling techniques, ANFIS modeling can effectively be employed for prediction of flow stress of 6061 Al-15% SiC composites. The convergence speed of this algorithm is higher than that of the ANN.
Temperature-dependence relaxation time of OH side groups versus 1/T for chitosan films in the hea... more Temperature-dependence relaxation time of OH side groups versus 1/T for chitosan films in the heating and cooling process. The solid lines represent Arrhenius-type dependence fitting. Schematic of proposed molecular interactions.
ABSTRACT This paper presents the details of a study on the measurement of oxygen flow by differen... more ABSTRACT This paper presents the details of a study on the measurement of oxygen flow by differential pressure method in a clinical ventilator system. The simulation results obtained from the COMSOL Multiphysics MEMS design tool show that the meso channel with a diameter of 1000 μm and length of 20 mm can cause measurable pressure drop between the upstream and downstreams without altering the flow and therefore can be used as a flow resistor. Two piezoresistive MEMS pressure sensors are proposed to be installed at the upstream and downstream to measure the differential pressure and thus the gas flow rate. Further investigations on thin film silicon diaphragms with embedded piezoresistors for sensing the upstream and downstream pressures show that it is essential to employ thin diaphragms for pressure sensing in this application to achieve higher sensitivity with reasonably good linearity. However very thin diaphragms results in more non linearity and are difficult to realize. Hence the authors have undertaken a study on perforated thick diaphragms for pressure sensing in piezoresistive MEMS pressure sensors for such applications. The IntelliSuite MEMS design tool has been used to create and analyze the performance of perforated diaphragm employed piezoresistive pressure sensors on 3 μm, 5 μm and 7 μm thick diaphragms each with different side lengths of 500 μm, 700 μm and 900 μm. The results show that it is possible to achieve more than 93% improvement in deflection sensitivity, more than 136% improvement in stress generation and 83% improvement in voltage sensitivity with 40 % perforated area irrespective of the thickness of the diaphragm. Empirical results on perforated diaphragms have been reported to be matching with COMSOL Multiphysics simulation results. Therefore the authors have simulated the perforated diaphragms studied in this work using COMSOL Multiphysics and compared with the IntelliSuite simulation results. The comparison confirms the validity of the results. A modified analytical model developed in this study for perforated diaphragm load-deflection performance show that the simulation obtained for various pressure sensors employing perforated diaphragms in this study are accurate and valid. This leads to the conclusion that the perforation realized on thicker diaphragms are suitable alternatives with satisfactory performance to very thin non-perforated diaphragms. The flow using the piezoresistive pressure sensors employing perforated diaphragms for differential pressure measurement are found to be giving larger flow sensitivity than the 1differential flow sensors already reported in the literature. This work therefore demonstrates that it is possible to design micro gas flow measurement system by differential pressure method using micro pressure sensors with perforated diaphragms integrated with meso channel.
The relationship between electrical conductivity, structure and antibacterial properties of chito... more The relationship between electrical conductivity, structure and antibacterial properties of chitosan-silver nanoparticles (CS/AgnP) biocomposites has been analyzed. To test the film's antimicrobial activity, Gram-positive and Gram-negative bacteria were studied. The interactions between silver nanoparticles with chitosan suggest the formation of silver ions which plays a major role in nanocomposite's bactericidal potency. In CS/AgnP biocomposites, the bactericide effectiveness increases by increasing AgnP concentrations up to 3 wt%, which is close to the electrical percolation threshold of ca. 3 wt%. As the AgnP concentration increases above this threshold, the bactericidal potency is greatly diminished. The elucidated correlation between electrical conductivity and antibacterial activity could be useful in the design of other nanocomposites that involve polymeric-based matrices. Highlights We report the synthesis and characterization of films of chitosan (CS)/Ag nanoparticles with bactericidal activity. Bactericide effectiveness increases by increasing Ag nP concentrations up to 3 wt%, which is close to the electrical percolation threshold of ca. 3 wt%. XPS analysis shows the presence of ca. 15% vol. of Ag ions that are a requisite for maximum bactericide activity. The elucidated correlation between electrical properties and antibacterial activity could be useful in the design of other nanocomposites.
Abstract Exploration carried out along lineaments identified by aerial photo interpretation in ha... more Abstract Exploration carried out along lineaments identified by aerial photo interpretation in hard rocks had revealed the existence of deep weathered and fractured zones capable of yielding up to 45,000 litres of groundwater per hour. Integrated studies of aerial photo interpretation followed up by hydrogeological and geophysical surveys was conducted in Hindupur taluk of Anantapur district in Andhara Pradesh for identification of groundwater potential zones for drinking water and for sugarcane development. Aerial photos of scale 1:63,000 were used covering an area of 1,600 km 2 . A number of lineaments running in NW-SE and NE-SW direction were identified using aerial photo interpretation. The studies have indicated a high density in lineaments in Dharwar rocks in Pennar and Jayamangali river basins and moderate to poor density of lineaments in granitic gneisses in Kushavathi and Chitravathi river basins. Fluvial deposits (alluvium), valleyfill deposits and pediment zones were also deciphered. Field checks during surveys along lineaments led to drilling of exploratory borewells. The drilling results indicated that the lineament zones are highly productive for construction of borewells, the maximum discharge being 45,000 litres per hour and the minimum being 9,000 litres per hour. Groundwater is mainly confined to weathered, fractured and fissured granites, gneisses and schists. Analysis of the lithologs indicated and increase in discharge in the fissured and fractured zones and at the contact of the different formations. The result of surveys along lineaments gives an insight into exploitation of groundwater along lineaments by means of borewells ranging in depths of up to 60 metres.
Learning and Analytics in Intelligent Systems, 2019
In an advanced electrical power system, a wide range of loads used by industrial, domestic, irrig... more In an advanced electrical power system, a wide range of loads used by industrial, domestic, irrigation, traction loads, commercial applications, advanced machinery of different electrical drives, control systems, and proliferation of different electronic gadgets day to day life, road, rail transport systems etc., have a greater impact on power quality. Another power quality issue is due to lesser power generating capacity of existing conventional resources and the combined operation of non-conventional energy resources into the power systems as hybrid electrical power generating systems. In this paper to decrease the gap between electrical power generation and demand added proton exchange membrane fuel cell as a hybrid electrical power system and addressed different power quality issues arise in power systems due to different loading conditions, impact of the tower shadowing effect of wind energy system in a weak grid system. A power electronics device: UPQC build up with instantaneous power theory to address these power quality issues within international standards.
To prevent the illegal copying and sharing of digital content, the need for security for digital ... more To prevent the illegal copying and sharing of digital content, the need for security for digital data is highly demanded. Among various available techniques, digital watermarking is an effective solution to protect confidential data. This paper presents the performance analysis of color image watermarking based on lifting scheme in which color image watermark has been used. Peak signal-to-noise ratio (PSNR), Structural similarity (SSIM) index and normalized correlation coefficient (NCC), etc. have been used as fidelity parameters to test the effectiveness of presented work both quantitatively and qualitatively.
The world celebrates over 50 years since the first human-to-human heart transplant. Bibliometric ... more The world celebrates over 50 years since the first human-to-human heart transplant. Bibliometric analysis is a statistical concept that has recently evolved, enabling scientists to study citation patterns and identify characteristics of highly cited scholarly work in different fields. Although it has been widely utilized, such analyses have not been conducted to date on heart transplant literature. We sought to assess the characteristics of the top 100 most referenced citations in the field of heart transplantation. We searched the Scopus database (www.scopus.com) to identify all articles relating to heart transplantation. The articles were arranged in descending order from most cited to least cited and selected articles were scrutinized for data extraction. One hundred articles were included in the final list. Of the total 40,660 citations identified, 3,210 (8.0%) were self-citations, which impacted the final rank order. The articles were published in 25 different journals between 1960 and 2013. The most productive 5-year time period was between 2000 and 2005, when 24 of the 100 most cited publications were produced. There was no correlation between the journals' impact factors and the number of articles produced per journal. The presence and type of funding were not associated with the number of citations. Over 85% of first and senior investigators were men. In conclusion, our study highlights key features of the most highly cited scientific literature on heart transplantation and provides insights into trends of published work in this field. Additionally, this work may serve as a useful guide to researchers and funding bodies by highlighting the most prolific areas of cardiac transplant research to date.
Mosquitoes transmit serious human diseases, causing millions of deaths every year. The use of syn... more Mosquitoes transmit serious human diseases, causing millions of deaths every year. The use of synthetic insecticides to control vector mosquitoes has caused physiological resistance and adverse environmental effects in addition to high operational cost. Insecticides of synthesized natural products for vector control have been a priority in this area. In the present study, silver nanoparticles (AgNPs) synthesized using Cassia roxburghii plant leaf extract against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus were determined. Larvae were exposed to varying concentrations of synthesized AgNPs (12, 24, 36, 48, and 60 μg/mL) and aqueous leaf extracts (60, 120, 180, 240, and 300 μg/mL) for 24 h. The synthesized AgNPs were characterized by UV-Vis spectrum, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), with energy-dispersive X-ray spectroscopy analysis (EDX), transmission electron microscopy, and X-ray diffraction analysis (XRD). Compare to aqueous extracted synthesized AgNPs showed extensive mortality rate against An. stephensi, Ae. aegypti, and C. quinquefasciatus with the LC50 and LC90 values that were 26.35, 28.67, 31.27 and 48.81, 53.24, and 58.11 μg/mL, respectively. No mortality was observed in the control. This is the first report on mosquito larvicidal activity of plant-synthesized nanoparticles. Thus, the use of C. roxburghii to synthesize silver nanoparticles is a rapid, eco-friendly, and a single-step approach, and the AgNPs formed can be potential mosquito larvicidal agents. Therefore, this study proves that C. roxburghii is a potential bioresource for stable, reproducible nanoparticle synthesis (AgNPs) and also can be used as an efficient mosquito control agent. This is the first report on the larvicidal activity of the plant extract and AgNPs.
In the present study an attempt was made to control the microstructure evolution during extrusion... more In the present study an attempt was made to control the microstructure evolution during extrusion using the NARMA_L2 Control approach with Neural Networks. The final grain size after extrusion was considered as the optimal criterion and the grain size was expressed in terms of strain, strain rate and temperature. The steps involved in NARMA _L2 Control approach include process modelling, system identification and controller design. The trajectories of the independent variables to achieve the desired grain size were obtained and the strain values were further utilized to optimize the dimensions of the extrusion die profile to achieve the required grain size.
Structure-controlled synthesis of gold nanostructures (AuNSs) induced by temperature in a nonaque... more Structure-controlled synthesis of gold nanostructures (AuNSs) induced by temperature in a nonaqueous urea–choline chloride deep eutectic solvent (DES) is reported.
In this study, Leucas aspera whole plant methanolic extract were examined for their phytochemical... more In this study, Leucas aspera whole plant methanolic extract were examined for their phytochemical profile by high-performance thin layer chromatographic (HTPLC) method. Alkaloids, Steroids and Flavonoids profile were analysed. Our results revealed that at least two types of alkaloids were seen in this methanolic extracts. Six types of flavonoids and two types of steroids were found in the Leucas aspera whole plant methanolic extract. Alkaloid and flavonoid were found to have higher concentration when compared to steroids which were in lower concentration in the methanolic extract.
Modeling and simulation provide objective analysis tools for many fields including manufacturing.... more Modeling and simulation provide objective analysis tools for many fields including manufacturing. This paper presents the requirements and describes the usefulness of a web-based interface to discrete-event simulation. A description of related efforts is first presented and an approach is then described. The approach develops a webbased interface to use commercial discrete-event commercial tools.
Protease producing halotolerant bacterium was isolated from saltern pond sediment (Tuticorin) and... more Protease producing halotolerant bacterium was isolated from saltern pond sediment (Tuticorin) and identified as Bacillus licheniformis (TD4) by 16S rRNA gene sequencing. Protease production was enhanced by optimizing the culture conditions. The nutritional factors such as carbon and nitrogen sources, NaCl and also physical parameters like incubation time, pH, agitation, inoculum size were optimized for the maximum yield of protease. Studies on the effect of different carbon and nitrogen sources revealed that xylose and urea enhances the enzyme production. Thus, with selected C-N sources along with 1 M NaCl the maximum protease production (141.46 U/mg) was obtained in the period of 24 h incubation at pH 8 under 250 rpm compared to the initial enzyme production (89.87 U/mg).
Mahseer are popularly regarded by anglers as the king of freshwater fishes, and are valued across... more Mahseer are popularly regarded by anglers as the king of freshwater fishes, and are valued across the Himalayan and South-east Asian regions. In India, mahseer are important game fish. Mahseer populations and their habitats face a range of anthropogenic threats, however, including unregulated fishing and habitat fragmentation as a result of hydro-development projects. Catch-and-release angling for mahseer attracts both national and international anglers and could provide information about rivers while generating revenue for regional economies. In this context, we evaluated catch-and-release angling records from rivers that flow within two Indian reserves (the Ramganga and Jia Bharali Rivers in Corbett and Nameri Tiger Reserves, respectively). Golden mahseer Tor putitora in the Ramganga and golden and chocolate mahseer Neolissochilus hexagonolepis in the Jia Bharali were the most frequently caught fish species. Catch data suggested these game fish populations are probably not negativ...
Silicon carbide reinforced aluminium composite materials are increasingly used in many engineerin... more Silicon carbide reinforced aluminium composite materials are increasingly used in many engineering fields. Flow stress prediction for these materials is increasingly important. In the present work, flow stress of 1.0Mg-0.6% Si-0.3% Cu-0.2% Cr rest Al with 15% SiC p during hot deformation is carried out using the conventional regression method, artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) method. The temperature at which the aluminium is compressed are 300-500°C with strain rates ranging from 0.00857 to 2.7 s À1 and for the strains of 0.1-0.5. Simulation studies are carried out for analysis. By comparing the performances of various modeling techniques, ANFIS modeling can effectively be employed for prediction of flow stress of 6061 Al-15% SiC composites. The convergence speed of this algorithm is higher than that of the ANN.
Temperature-dependence relaxation time of OH side groups versus 1/T for chitosan films in the hea... more Temperature-dependence relaxation time of OH side groups versus 1/T for chitosan films in the heating and cooling process. The solid lines represent Arrhenius-type dependence fitting. Schematic of proposed molecular interactions.
ABSTRACT This paper presents the details of a study on the measurement of oxygen flow by differen... more ABSTRACT This paper presents the details of a study on the measurement of oxygen flow by differential pressure method in a clinical ventilator system. The simulation results obtained from the COMSOL Multiphysics MEMS design tool show that the meso channel with a diameter of 1000 μm and length of 20 mm can cause measurable pressure drop between the upstream and downstreams without altering the flow and therefore can be used as a flow resistor. Two piezoresistive MEMS pressure sensors are proposed to be installed at the upstream and downstream to measure the differential pressure and thus the gas flow rate. Further investigations on thin film silicon diaphragms with embedded piezoresistors for sensing the upstream and downstream pressures show that it is essential to employ thin diaphragms for pressure sensing in this application to achieve higher sensitivity with reasonably good linearity. However very thin diaphragms results in more non linearity and are difficult to realize. Hence the authors have undertaken a study on perforated thick diaphragms for pressure sensing in piezoresistive MEMS pressure sensors for such applications. The IntelliSuite MEMS design tool has been used to create and analyze the performance of perforated diaphragm employed piezoresistive pressure sensors on 3 μm, 5 μm and 7 μm thick diaphragms each with different side lengths of 500 μm, 700 μm and 900 μm. The results show that it is possible to achieve more than 93% improvement in deflection sensitivity, more than 136% improvement in stress generation and 83% improvement in voltage sensitivity with 40 % perforated area irrespective of the thickness of the diaphragm. Empirical results on perforated diaphragms have been reported to be matching with COMSOL Multiphysics simulation results. Therefore the authors have simulated the perforated diaphragms studied in this work using COMSOL Multiphysics and compared with the IntelliSuite simulation results. The comparison confirms the validity of the results. A modified analytical model developed in this study for perforated diaphragm load-deflection performance show that the simulation obtained for various pressure sensors employing perforated diaphragms in this study are accurate and valid. This leads to the conclusion that the perforation realized on thicker diaphragms are suitable alternatives with satisfactory performance to very thin non-perforated diaphragms. The flow using the piezoresistive pressure sensors employing perforated diaphragms for differential pressure measurement are found to be giving larger flow sensitivity than the 1differential flow sensors already reported in the literature. This work therefore demonstrates that it is possible to design micro gas flow measurement system by differential pressure method using micro pressure sensors with perforated diaphragms integrated with meso channel.
The relationship between electrical conductivity, structure and antibacterial properties of chito... more The relationship between electrical conductivity, structure and antibacterial properties of chitosan-silver nanoparticles (CS/AgnP) biocomposites has been analyzed. To test the film's antimicrobial activity, Gram-positive and Gram-negative bacteria were studied. The interactions between silver nanoparticles with chitosan suggest the formation of silver ions which plays a major role in nanocomposite's bactericidal potency. In CS/AgnP biocomposites, the bactericide effectiveness increases by increasing AgnP concentrations up to 3 wt%, which is close to the electrical percolation threshold of ca. 3 wt%. As the AgnP concentration increases above this threshold, the bactericidal potency is greatly diminished. The elucidated correlation between electrical conductivity and antibacterial activity could be useful in the design of other nanocomposites that involve polymeric-based matrices. Highlights We report the synthesis and characterization of films of chitosan (CS)/Ag nanoparticles with bactericidal activity. Bactericide effectiveness increases by increasing Ag nP concentrations up to 3 wt%, which is close to the electrical percolation threshold of ca. 3 wt%. XPS analysis shows the presence of ca. 15% vol. of Ag ions that are a requisite for maximum bactericide activity. The elucidated correlation between electrical properties and antibacterial activity could be useful in the design of other nanocomposites.
Abstract Exploration carried out along lineaments identified by aerial photo interpretation in ha... more Abstract Exploration carried out along lineaments identified by aerial photo interpretation in hard rocks had revealed the existence of deep weathered and fractured zones capable of yielding up to 45,000 litres of groundwater per hour. Integrated studies of aerial photo interpretation followed up by hydrogeological and geophysical surveys was conducted in Hindupur taluk of Anantapur district in Andhara Pradesh for identification of groundwater potential zones for drinking water and for sugarcane development. Aerial photos of scale 1:63,000 were used covering an area of 1,600 km 2 . A number of lineaments running in NW-SE and NE-SW direction were identified using aerial photo interpretation. The studies have indicated a high density in lineaments in Dharwar rocks in Pennar and Jayamangali river basins and moderate to poor density of lineaments in granitic gneisses in Kushavathi and Chitravathi river basins. Fluvial deposits (alluvium), valleyfill deposits and pediment zones were also deciphered. Field checks during surveys along lineaments led to drilling of exploratory borewells. The drilling results indicated that the lineament zones are highly productive for construction of borewells, the maximum discharge being 45,000 litres per hour and the minimum being 9,000 litres per hour. Groundwater is mainly confined to weathered, fractured and fissured granites, gneisses and schists. Analysis of the lithologs indicated and increase in discharge in the fissured and fractured zones and at the contact of the different formations. The result of surveys along lineaments gives an insight into exploitation of groundwater along lineaments by means of borewells ranging in depths of up to 60 metres.
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Papers by Siva Kumar