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In this research work, the tungsten diselenide (WSe2)-based thin-film solar cell with a copper thiocyanate (CuSCN) hole transport layer (HTL) has been designed and studied by using the Solar Cell Capacitance Simulator in One Dimension software program (SCAPS-1D). A comparative numerical study between Al/ITO/CdS/WSe2/Ni and Al/ITO/CdS/WSe2/CuSCN/Ni has been done. The SCAPS-1D simulator has been utilized to investigate photovoltaic parameters such as open circuit voltage, short-circuit current density, fill-factor, power conversion efficiency and quantum efficiency of heterojunction solar cell due to the variation of thickness, doping density, bulk defect density, defect density at buffer/absorber and absorber/HTL interfaces, operating temperature, band alignment and back surface recombination velocity. The conversion efficiency of 17.33% has been determined for the WSe2 solar cell without HTL. On the contrary, the efficiency of the proposed solar cell with CuSCN HTL has been found to be 24.20% at the optimal device structure. These numerical findings of the present study may therefore provide an intuitive approach to fabricate an economically feasible and highly efficient WSe2-based heterojunction thin-film solar cell.

This paper presents the design of a compact circular microstrip patch antenna for WLAN applications which covers the band 5.15 to 5.825 GHz. The antenna is designed using 1.4mm thick FR-4 (lossy)substrate with relative permittivity 4.4 and a microstrip line feed is used. The radius of the circular patch is chosen as 7.62mm. To reduce the size and enhance the performance of the proposed antenna, a circular slot is loaded on circular patch and a square slot is etched on the ground plane of dimension 30mm×30mm. Design of the antenna is carried out using CST Microsoft Studio Sonimulation Software. The proposed antenna resonates at 5.5 GHz with a wider bandwidth of 702 MHz and it provides low return loss of -31.58 dB, good gain of 3.23 dB and directivity of 4.28 dBi and high efficiency of around 79% against the resonance frequency. The geometry of the proposed circular antenna with reduced size and its various performance parameters such as return loss, bandwidth, VSWR, gain, directivity, efficiency and radiation pattern plots are presented and discussed

Digital modulation increases information capacity, data security, and system availability while maintaining high communication quality. As a result, digital modulation techniques are in higher demand than analog modulation techniques due to their ability to transmit larger amounts of data. Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK), Phase Shift Keying (PSK), Differential Phase Shift Keying (DPSK), and Quadrature Amplitude Modulation (QAM) are critical components of current communications systems development, particularly for broadband wireless communications. In this paper, the comparison of bit error rate performance of different modulation schemes (BPSK, QPSK, and16-QAM) and various equalization techniques such as constant modulus algorithm (CMA) and maximum likelihood sequence estimate (MLSE) for the AWGN and Rayleigh fading channels is analyzed using Simulink. BPSK outperforms QPSK and 16-QAM when compared to the other two digital modulation schemes. Among the three digital modulation schemes, BPSK is showing better performance as compared to QPSK and 16-QAM.

Wireless communications are among the rapidly growing fields in our current life and have a massive effect on every aspect of our everyday life. In this paper, the performance of the various digital modulation techniques (BPSK, DPSK, QPSK, and QAM) based wireless communication system on the audio signal transmission through the additive Gaussian Noise (AWGN) channel is assessed on the basis of bit error rate (BER) as a function of the signal-to-noise ratio (SNR). Based on the results of this study, BPSK modulation outperforms the DPSK, QPSK, and QAM modulation strategies in the MIMO MC-CDMA VBlast based wireless communication system. The digital modulation of QPSK shows the worst performance in audio signal transmission especially in comparison to other digital modulations. It is clear from the current simulation study based on MATLAB that the V-Blast encoded 4×4 MIMO MC-CDMA wireless system with minimum mean square error (MMSE) signal detection and 1⁄2-rated convolution and cyclic redundancy check (CRC) channel encoding strategies show good performance utilizing BPSK digital modulation in audio signal transmission.

We have Developed an IoT-based real-time solar power monitoring system in this paper. It seeks an opensource IoT solution that can collect real-time data and continuously monitor the power output and environmental conditions of a photovoltaic panel.The Objective of this work is to continuously monitor the status of various parameters associated with solar systems through sensors without visiting manually, saving time and ensures efficient power output from PV panels while monitoring for faulty solar panels, weather conditionsand other such issues that affect solar effectiveness.Manually, the user must use a multimeter to determine what value of measurement of the system is appropriate for appliance consumers, which is difficult for the larger System. But the Solar Energy Monitoring system is designed to make it easier for users to use the solar system.This system is comprised of a microcontroller (Node MCU), a PV panel, sensors (INA219 Current Module, Digital Temperature Sensor, LDR), a Battery Charger Module, and a battery. The data from the PV panels and other appliances are sent to the cloud (Thingspeak) via the internet using IoT technology and a Wi-Fi module (NodeMCU). It also allows users in remote areas to monitor the parameters of the solar power plant using connected devices. The user can view the current, previous, and average parameters of the solar PV system, such as voltage, current, temperature, and light intensity using a Graphical User Interface. This will facilitate fault detection and maintenance of the solar power plant easier and saves time.

This paper presents the development of a sensor based smart irrigation system with the capabilities of remote monitoring and controlling of water usage in the agriculture field using Internet of Things (IoT). With the employment of IoT in irrigation system, all agricultural information can be viewed and controlled at the user's fingertips. The system consists of a microcontroller (Node MCU), sensors (soil moisture, DHT11), and irrigation of a water pump with a decision-making system. Sensors are linked to a Wi-Fi module (Node MCU) and are interdependent to provide increased sensitivity to the irrigation system. The data obtained will be uploaded to the cloud (ThingSpeak) and presented in the form of graphs accessible via the website. A web page is used to control the water pump for irrigation purposes. This paper is managed to meet all of its aims to help farmers in terms of time, project cost, labor, water consumption, power consumption, and reliability by implementing the IoT-based smart irrigation system.

The bit error rate performance of a V-Blast encoded 8x8 MIMO MC-CDMA wireless communication system for different signal detection (MMSE and ZF) and digital modulation (BPSK, QPSK, DPSK, and 4QAM) schemes for grayscale image transmission has been investigated in this paper. The proposed wireless system employ ½-rated Convolution and cyclic redundancy check (CRC) channel encoding over the AWGN channel and Walsh Hadamard code as an orthogonal spread code. The present Matlab based simulation study demonstrates that the V-Blast encoded 8×8 MIMO MC-CDMA wireless system with the employment of 1⁄2- rated convolution and cyclic redundancy check (CRC) channel encoding strategies shows good performance utilizing BPSK digital modulation and ZF signal detection scheme in grayscale image transmission.

In this paper, the impact of patch and ground plane slots on the bandwidth performance of a microstrip UWB antenna is presented. Our reference antenna is a microstrip feeding type monopole feature with a rectangular patch and a partial ground plane. In order to evaluate the characteristics of the reference antenna bandwidth, two separate slot types (right-angle triangular and rectangular) have been inserted into the patch and a single slot configuration like a rectangular is also inserted into the partial ground plane on the backside of the feed line to the appropriate. The influence on the bandwidth characteristics of single and multiple slot cases is analyzed using the HFSS simulator. Based on the slot configurations, the simulation results verify that the antenna bandwidth can be improved.

Energy consumption is a significant issue for data forwarding in Delay-Tolerant Network (DTN), where nodes are energy-constrained as they are driven by batteries. During their limited lifetime, these nodes have to spend a huge amount of energy since they perform forwarding, receiving, and temporarily storing messages, searching for the neighboring nodes for message forwarding, etc. The remaining energy of a node is expected to be higher as it increases the possibility of successful message delivery. Hence, awareness of energy expenditure is necessary for the routing strategies in DTN. This issue instigated us to evaluate the impact of node remaining energy on social-based routing protocols for the DTN scenario. Apart from the conventional DTN forwarding techniques, social-based forwarding protocols have involved an emerging concept that considers nodes’ social relations and behaviors to make routing decisions for efficient message transmission. In this paper, we have analyzed the energy efficiency of several social-based routing approaches, such as Social-aware Content-based Opportunistic Routing Protocol (SCORP), dLife, dLifeComm, and Bubble Rap with their corresponding performance evaluations regarding the performance metrics: average remaining energy, delivery ratio, average delay, and transmission cost. Opportunistic Network Environment (ONE) simulator is used as the simulation tool, where all the simulations are performed by (i) varying the number of nodes in each group with a fixed message Time-To-Live (TTL), and (ii) changing the message TTL, while the number of nodes per group is kept constant. From the outcome of simulations, it is observed that SCORP has the highest energy efficiency and shows the best performances for average delay and transmission cost.

Delay-Tolerant Network (DTN) is a resource-bound networking system which consists of many intermittently connected, movable devices known as nodes. Energy can be considered as an important resource for DTN scenarios since these nodes have limited energy. In order to perfect network enforcement, it is necessary to exploit the energy of the nodes efficiently. In DTN, most of the node energy is consumed because of mobility, scanning neighbors to deliver message and message transmission. Node energy has a significant role for successful transmission of messages. Higher energy of a node means that it has a high possibility to route its message with success across the network. So, for effective message routing it is mandatory to select an energy efficient routing mechanism in DTN environment. This point makes us interested to study the consumption of node energy in DTN scenarios. Within this research, the study of energy issue is focused for DTN routing approaches: Epidemic, Resource Allocation Protocol for Intentional DTN (RAPID), MaxProp, Probabilistic Routing Protocol using History of Encounters and Transitivity (PRoPHET), Spray and Wait, and Spray and Focus with their comparative performance analysis on behalf of four performance criteria: average remaining energy of node, delivery ratio, average latency, and transmission cost. Simulations are performed in Opportunistic Network Environment (ONE) simulator by varying node density while keeping message Time-To-Live (TTL) fixed and further, message TTL is changed while node density is kept fixed. We have found that Spray and Wait is the most energy efficient DTN routing scheme, whereas Spray and Focus yields the best performance in terms of delivery ratio, average latency and transmission cost.

We have developed an optical method of detecting and characterizing nonradiative recombination (NRR) centers without electrical contact. The method combines a below-gap excitation (BGE) light with a conventional above-gap excitation light in photoluminescence (PL) measurement, and discriminates the PL intensity change due to switching on and off the BGE. A quantitative analysis of the detected NRR centers became possible by utilizing the saturating tendency of the PL intensity change with increasing the BGE density due to trap filling effect. Some experimental results of AlGaAs, InGaN, and AlGaN quantum wells were shown to allocate the development and present status as well as to exemplify their interpretations.