Conference Papers
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Item Studies on gravity backfilling method for blind backfilling of abandoned coal mines(TMMOB Maden Muhendisleri Odasi, 2015) Pal, S.K.; Panda, S.; Tripathi, A.K.In this paper a new, simple and low cost gravity backfilling method for stabilization of ground above abandoned underground mines is proposed. Laboratory investigations carried out on this simple gravity hydraulic blind backfilling method to fill up a fully transparent model of a section of a bord and pillar mine, have indicated that deposition of the filling material surrounding the inlet hole occurs in a regular shape with full packing up to the roof. Some empirical relationships on maximum volume of sand throughput and spread of sand around the inlet hole have been developed with a view to help the practicing engineers. In the field trial the spread of sand in different directions has been witnessed using an ROV camera fitted with a sonar imaging system. The shape and nature of deposited sand bed surrounding the feeder hole in field and laboratory studies are alike. The empirical relationships developed under field conditions have also been found to be similar to those of laboratory model.Item Contrast Preserving Tone Reproduction for High Dynamic Range Images(Institute of Electrical and Electronics Engineers Inc., 2016) Jaiswal, S.; Tripathi, A.K.An exact replica of a high dynamic range image which embeds withinit a wide range of luminance values on a standard display device(e.g. LCD monitor) is impossible to achieve without significant lossof information as the display devices are designed to handle verylow range of intensity values compared to the high dynamic rangescene. We propose an algorithm whose output is visually pleasingand preserves maximum information from the input image. In additionto that, proposed method is fast and easy to implement. Proposedalgorithm uses the local and global histogram information of theimage and produces the best tone mapped image. Results verify theefficiency of the algorithm. Proposed algorithm requires noparameter adjustment which makes it useful for any image dataset. © 2016 IEEE.Item Design and development of Tilted Single Axis and Azimuth-Altitude Dual Axis Solar Tracking systems(Institute of Electrical and Electronics Engineers Inc., 2017) Ray, S.; Tripathi, A.K.The green energy also called the renewable energy, has gained much attention nowadays. Among the renewable energy solutions, solar energy is the very vital source that can be used to generate power. Electricity from the sun can be converted through photovoltaic (PV) module. The efficiency of solar module depends on sun intensity, if the intensity is more then efficiency is more. Since the position of sun continuously changes throughout the day, the intensity of sun rays is not uniform on PV module. So, for getting more sun rays on PV module solar tracker plays a much vital role. A solar tracker is a device for operating a solar photovoltaic panel, especially in solar cell applications and requires high degree of accuracy to ensure that the concentrated sunlight is dedicated precisely on to the power device. This paper describes in detail about the design, development and fabrication of two Prototype Solar Tracking Systems mounted with a single-axis and dual-axis solar tracking controllers to generate 10.3 volts, 1.5 watts capable of charging mobile batteries. The rays from the sun should fall perpendicularly onto the solar panels to maximize the capture of the rays and this is done by pointing the solar panels towards the sun and following its path across the sky. The solar tracking systems - Tilted Single Axis Tracker (TSAT) and Azimuth-Altitude Dual Axis Tracker (AADAT) are designed, implemented and experimentally tested. The design details of TSAT and AADAT are described which detect the sunlight using Light Dependent Resistor (LDR) sensors. The control circuit for the systems is based on Atmega8 Microcontroller which is programmed to detect the sunlight through the LDR sensors and then actuate the DC geared motor using L293D motor driver to position the solar panel where it can receive the maximum sunlight. © 2016 IEEE.Item Effect of shading on PV panel technology(Institute of Electrical and Electronics Engineers Inc., 2018) Tripathi, A.K.; Murthy, C.S.N.Solar photovoltaic energy conversion has gained much attention nowadays. The performance of solar photovoltaic system mainly depends on the solar radiation falling on the panel surface. Shading across the panel surface is the main cause for the degradation of its performance. It was found that due to 25% shading strength in mono crystalline PV panel the reduction in short circuit current and maximum power output was respectively 40.72% and 41.40%. Similarly, the reduction in short circuit current and maximum power output was 60.86% and 61.80%, respectively for poly crystalline panel. Under the same level of shading the monocrystalline PV panel shows less reduction in its performance when compared to poly crystalline PV panel. © 2017 IEEE.Item Laboratory investigation of photovoltaic panel performance under the shaded condition(Institute of Electrical and Electronics Engineers Inc., 2020) Tripathi, A.K.; Mangalpady, M.; Ray, S.; Parida, S.The most encouraging use of solar energy is its conversion into electrical energy by using solar photovoltaic (PV) panel. The performance of solar-based PV panel is undoubtedly influenced by the quantity of solar radiation, which is reaching on the panel surface. The occurrence of shading over the panel surface is a vital environmental phenomenon which affects the penetration of solar radiation to reach the overall surface area of photovoltaic cells. The shading on PV panels may happen due to trees, the formation of mists, accumulation of dirt elements on the panel surface, close by long-standing structures, shadows of different panels in its region, neighbouring structures and so on. This paper is mainly focused on the study of shading impact on the panel performance. Further, this paper also observed the influence of shading on the variation of surface temperature of the PV panel. The present study shown a significant reduction of 41.40% in the maximum power output (Pmax) of the panel due to 25% shading strength of the single cell in the panel. Moreover, it was also observed that the increase in the percentage shading strength over the panel surface shifts the maximum power point (MPP), of the panel characteristics, towards the lower output voltage, which affects the effective operation of the charge controller. Further, it was seen that the shading impact degrades the performance of the panel as well as in charge of the rise of the surface temperature of the panel. In the present investigation, it was observed that the temperature of the unshaded cell rises at the rate of 1.753%, due to the shading phenomena over the panel surface. © 2020 IEEE.Item Evaluation of solar PV panel performance under humid atmosphere(Elsevier Ltd, 2020) Tripathi, A.K.; Ray, S.; Mangalpady, A.; Prasad, S.The main aim of this paper is to study the effects of humidity on the PV panel. In this paper, the panel performance was studied in the laboratory under varied humid atmosphere. The PV performance parameters were computed by measuring its output voltage and current, amount of solar radiation incident on the panel's surface and its surface temperature by varying humidity levels artificially in the laboratory. From the studies it was observed that with rising humidity levels, solar insolation and panel power output decrease. With an increment of 50.15% in the humidity level, the panel power output reduces by 34.22%. Moreover, it was found that due to the increase in humidity from 65.40% to 98.20% the panel temperature got lowered by 11.40%. © 2020 Elsevier Ltd. All rights reserved.Item MWD technique to estimate the uniaxial compressive strength of rocks(American Institute of Physics Inc. subs@aip.org, 2020) Lakshminarayana, C.R.; Tripathi, A.K.; Pal, S.K.The measurement of mechanical properties of rocks is an essential task to be carried out during the projects involving the rock engineering activities such as civil constructions, tunneling, excavations etc. Although the quantification of uniaxial compressive strength in the laboratory is much faithful, the availability of rock samples and their preparation according to ISRM standards is the major limitation. In this experimental investigation, the quantification of the uniaxial compressive strength (UCS) of rocks using the measurement while drilling (MWD) technique was attempted. During the drilling of dissimilar strength rocks for various combinations of drilling operational parameters, the value of thrust and torque were collected using the digital type drilling dynamometer. The prediction of the UCS was performed by developing a mathematical model considering the parameters used for operating the machine and corresponding thrust and torque values. The prediction capacity of developed model was evaluated using the value account for (VAF), root mean square error (RMSE) and mean absolute percentage error (MAPE). From the results it was concluded that the MWD technique could be a prominent tool for estimation of rock strength properties in future. © 2020 Author(s).Item Quantification of Rock Strength Using the Mechanical Drilling Parameters(Springer Nature, 2020) Lakshminarayana, C.R.; Tripathi, A.K.; Pal, S.K.The estimation of rock strength is most often required for the preliminary stage of rock engineering projects. The determination of rock strength properties in the laboratory is reliable, but the availability of a number of fine quality core samples for lab testing is very difficult. In this study, an attempt is made to investigate the usability of variations of thrust developed at the rock-bit interface and vibration frequency generated in the drilling machine head for estimation of rock strength during the rotary drilling. The variation of thrust and vibration frequency during drilling is measured using sophisticated digital type drilling dynamometer and data acquisition system (DAQ) with accelerometer sensor respectively. The second order regression models were developed to predict the rock strength such as uniaxial compressive strength considering the machine operating parameters and measured variables. The evaluation of the prediction ability of the developed models was checked using the three performance indices known as VAF, RMSE, and MAPE. The results revealed that the approached method is highly efficient for estimation of rock strength during rotary drilling. © 2020, Springer Nature Switzerland AG.Item Analysis on photovoltaic panel temperature under the influence of solar radiation and ambient temperature(Institute of Electrical and Electronics Engineers Inc., 2021) Tripathi, A.K.; Ray, S.; Mangalpady, M.The generation of electrical energy from solar energy is one of the most promising utilization of solar energy technology and it can be achieved by the application of solar photovoltaic (PV) panel. In this paper an experimental study has been conducted to examine the effect of solar radiation and ambient temperature on the surface temperature of the solar photovoltaic panel. With the help of experimental measurements, a multi-linear regression model is developed relating the three quantities. The developed model validated with the actual measured values shows good accuracy with small values of root mean square error. During the study, the recordedvalue of maximum panel temperature was 78.50°C for the atmospheric condition which having solar radiation of 1140 W/m2 and ambient temperature of 36°C. The developed relation and subsequent outcomes of the study will help the PV panel designers and manufacturers incomprehending the effects of atmospheric parameters on the temperature of the photovoltaic panel. © 2021 IEEEItem Design and Development of an IoT-Based Gas Monitoring System for Underground Coal Mines(Springer Science and Business Media Deutschland GmbH, 2023) Tripathi, A.K.; Mangalpady, M.; Rao, N.R.N.V.; Ray, S.Safety in underground coal mines is a major challenge whenever the mine comprises of toxic gases. The risk of the presence of gas influences the overall productivity of the mines, which is a subject of concern to the mining industry. Therefore, there is a need for real-time monitoring of underground mine environment, so that the miners can be safeguarded in case of presence of toxic gases. In this paper, an attempt was made to evolve and validate an Internet of Things (IoT)-based gas monitoring system for monitoring underground coal mines environment, which includes multiple sensors for real-time measurement of different gases. The developed IoT-based gas monitoring system was tested and validated in the laboratory, under the controlled environmental conditions, for the measurement of carbon dioxide (CO2), carbon monoxide (CO) and methane (CH4) gases. Further, the test results were compared with the readings obtained by the digital multi-gas detector, which confirmed that the developed real-time gas monitoring system yields a good result. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.