Browsing by Author "Murthy, A."

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Experimental investigation and ANN analysis of a four-intersecting-vane rotary expander in a micro-scale organic Rankine cycle system
(Elsevier Ltd, 2024) Murthy, A.; Naseri, A.; Shenoy, P.; Patil, I.S.
Organic Rankine cycles (ORCs) are often used for power generation from low-temperature waste heat. Although the ORC is a well-established technology for medium- to large-scale applications, several issues need to be resolved before it can be widely used in micro-scale applications, including the development of a reliable, low-cost, and efficient expander. A small-scale ORC experimental setup was built using R134 as the working fluid. This paper aims to investigate the performance of a four-intersection-vane rotary expander in a small-scale ORC system. The characteristics include filling factor, isentropic efficiency, and shaft power. The experiments are tested at suction temperatures up to 70 ℃, rotational speeds up to 900 rpm and suction pressures up to 11 bar (abs). The expander demonstrated shaft power of up to 73 W, minimum filling factor of 1.9, and isentropic efficiency of up to 45.6 %. The impacts of lubrication on the performance of the expander are discussed. Besides the experimental work, an Artificial Neural Network (ANN) and Genetic Algorithm (GA) modelling approach was proposed to achieve higher accuracy in mapping the expander's performance. The developed model is evaluated with different parameter settings, train functions and learning rates to increase the prediction accuracy. © 2024 The Author(s)
Experimental study on linear displacement measurement sensor using RGB color variation technique with PID controller
(2017) Murthy, A.; Rao, S.S.; Herbert, M.A.; Navin, Karanth, P.
This study is based on experimental approach to linear displacement measurement using RGB color coding algorithm. This system is based on the auto-calibration procedure which can be implemented in a circuit, based on the temporal changes in the intensity of light, with the help of a light dependent resistor (LDR). The system consists of two LDRs and an LED placed on one side and an RGB color coded reflective paper on the opposite side. PIC microcontroller is used for powering the LED, processing of data for feedback control and to display the output on an LCD. LDR1 reading is used for displaying the relative linear distance, by mapping the voltage as a function of distance. This reading is used as a feedback to a PID controller to correct for the deviation in the measurement. Extensive experimental observations are conducted to analyze the reliability of the results in accordance to the wavelength of light reflected, the signal voltage and power output of the system. Investigation of the optimum positioning of the LED and the reflective RGB color coded paper is performed by repeatability analysis and hysteresis effects. Furthermore, the efficiency of the system is increased by implementing a PID controller upon investigating the different controller design, viz. P, PI and PID. A high resolution of 0.1 [mm] is obtained for such a simple and economical system, thereby making it highly efficient, in both minute measurements as well as over the entire bandwidth range of the visible light spectrum. � 2017 IEEE.
Experimental study on linear displacement measurement sensor using RGB color variation technique with PID controller
(Institute of Electrical and Electronics Engineers Inc., 2017) Murthy, A.; Rao, S.S.; Herbert, M.A.; Karanth P, P.
This study is based on experimental approach to linear displacement measurement using RGB color coding algorithm. This system is based on the auto-calibration procedure which can be implemented in a circuit, based on the temporal changes in the intensity of light, with the help of a light dependent resistor (LDR). The system consists of two LDRs and an LED placed on one side and an RGB color coded reflective paper on the opposite side. PIC microcontroller is used for powering the LED, processing of data for feedback control and to display the output on an LCD. LDR1 reading is used for displaying the relative linear distance, by mapping the voltage as a function of distance. This reading is used as a feedback to a PID controller to correct for the deviation in the measurement. Extensive experimental observations are conducted to analyze the reliability of the results in accordance to the wavelength of light reflected, the signal voltage and power output of the system. Investigation of the optimum positioning of the LED and the reflective RGB color coded paper is performed by repeatability analysis and hysteresis effects. Furthermore, the efficiency of the system is increased by implementing a PID controller upon investigating the different controller design, viz. P, PI and PID. A high resolution of 0.1 [mm] is obtained for such a simple and economical system, thereby making it highly efficient, in both minute measurements as well as over the entire bandwidth range of the visible light spectrum. Â© 2017 IEEE.
Including peer and self-assessment in a continuous assessment scheme in electrical and electronics engineering courses
(2015) De, Sande, J.C.G.; Murthy, A.
During the last decades, different assessment approaches have been implemented in many higher education institutions in order to complement or even substitute the final exams. Here, an analysis of the implementation of a mixed assessment method (continuous assessment plus a final exam) in a Signals and Systems course is presented. The continuous assessment part includes several assessed activities and ways to assess a given activity: peer assessed homework, automatically assessed online tests, instructor assessed laboratory practices and self-assessed classroom written exercises. A voluntary survey that includes items about the course contents, about the weights assigned to each activity and about the influence of the assessment type in their achievement of the course goals is delivered at the end of semester. There is a high correlation between the continuous assessment marks and final exam marks. Survey responses show that the objectives of the course can be reasonably achieved, most of the students were in agreement with the weights assigned to each assessed activity, most of the students considered that conducting peer assessment was helpful for them, and most of the students considered that their self-assessment was more useful than being instructor assessed. � 2014 IEEE.
Including peer and self-assessment in a continuous assessment scheme in electrical and electronics engineering courses
(Institute of Electrical and Electronics Engineers Inc., 2015) GonzÃ¡lez de Sande, J.C.G.; Murthy, A.
During the last decades, different assessment approaches have been implemented in many higher education institutions in order to complement or even substitute the final exams. Here, an analysis of the implementation of a mixed assessment method (continuous assessment plus a final exam) in a Signals and Systems course is presented. The continuous assessment part includes several assessed activities and ways to assess a given activity: peer assessed homework, automatically assessed online tests, instructor assessed laboratory practices and self-assessed classroom written exercises. A voluntary survey that includes items about the course contents, about the weights assigned to each activity and about the influence of the assessment type in their achievement of the course goals is delivered at the end of semester. There is a high correlation between the continuous assessment marks and final exam marks. Survey responses show that the objectives of the course can be reasonably achieved, most of the students were in agreement with the weights assigned to each assessed activity, most of the students considered that conducting peer assessment was helpful for them, and most of the students considered that their self-assessment was more useful than being instructor assessed. Â© 2014 IEEE.