Reduced graphene oxide and molybdenum disulfide (rGO:MoS 2 ) are the most representative two-dimensional materials, which are promising for a humidity sensor owing to its high surface area, a large number of active sites, and excellent mechanical flexibility. Herein, we introduced a highly sensitive and stable rGO:MoS 2 -based humidity sensor integrated with a lowpower in-plane microheater and a temperature sensor, directly insertable to transformer insulating oil, and analyzed by a newly developed customized sensor interface electronics to monitor the sensor's output variations in terms of relative humidity (RH) concentration. rGO:MoS 2 sensing materials were synthesized by simple ultrasonication without using any additives or additional heating and selectively deposited on titanium/platinum (Ti/Pt) interdigitated electrodes on a SiO 2 substrate using the drop-casting method. The significant sensing capability of p−n heterojunction formation between rGO and MoS 2 was observed both in the air and transformer insulating oil environment. In air testing, the sensor exhibited an immense sensitivity of 0.973 kΩ/%RH and excellent linearity of ∼0.98 with a change of humidity from 30 to 73 %RH, and a constant resistance deviation with an inaccuracy rate of 0.13% over 400 h of continual measurements. In oil, the sensor showed a high sensitivity of 1.596 kΩ/%RH and stable repeatability for an RH concentration range between 34 and 63 %RH. The obtained results via the sensor interface were very similar to those measured with a digital multimeter, denoting that our developed total sensor system is a very promising candidate for realtime monitoring of the operational status of power transformers.

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Metal oxide nanostructures are the most promising materials for the fabrication of advanced gas sensors over two decades. Especially, reliable responsivity and selectivity for various harmful gases are the main requirements for the future chemiresistive‐type gas sensors. Here, a 3D nanocone (NC) of WO3 for a real‐time ethane (C2H6) gas sensor is reported. A compact WO3 nanoparticles thin film deposited on the sensor interdigitate electrodes (IDEs) by using radio frequency (RF) sputter and subsequently, WO3 thin film is converted into highly ordered 3D NC with simple monolayer of polystyrene. An in‐plane microheater integrated with a temperature sensor is also developed here in which the heater, temperature sensor, and the gas sensor share the same plane instead of a conventional vertical structure where the microheater and the sensor IDE are placed one above the other. Prior to the fabrication, COMSOL simulations are carried away to predict the heater performance and surface charge densities of the NC structures. A comparative study between the planar WO3 and highly ordered 3D NC WO3 in sensor response has been conducted. The fabricated sensors (planar WO3) and 3D NC WO3 show a high response ΔR/R (%) of 44% and 52% to 100 ppm of ethane at 200 °C respectively.

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A solar tracking system is designed for the orientation of different solar energy receivers, photovoltaic arrays or thermal receivers to maximize the operation of solar energy conversion. This paper deals with the design and implementation of a multidirectional solar tracking system dedicated to use with PV panels. The proposed solar tracking device ensures the maximization of the conversion of solar energy into electricity by properly orienting the PV panel in accordance with the real position of the sun. The dual axis solar tracker moves only in vertical direction with Y and Z-axis movement. It cannot move in horizontal direction with X-axis movement. Our proposed model can move in vertical position with Y-axis movement and in horizontal position with X-axis movement and also move at a point in Z-axis making combination of X and Y-axis movement. The gain of output power with the Multi-directional tracking system is higher when compared with a dual axis tracker. The performance of the proposed solar tracker was experimentally analyzed. Index Terms-: Multi-directional, Solar tracker system, Matrix Photo Sensors, Microcontroller.I.