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A wireless sensor network (WSN) is a collection of various tiny devices known as sensor nodes, which are also called motes. Due to high-energy consumption, the possibility of hardware, link or node failure, and some malicious attacks, sensor networks are considered error-prone networks. Hence, fault tolerance (FT) in WSN is one of the prominent issues. This paper presents a novel FT approach named nodelink failure fault tolerance model (NLFFT Model) in WSN, to handle the faults that occur either by link or node failure during data transmission from the sensor to the sink or base station. The NLFFT model consists of an improved quadratic minimum spanning tree (Imp-QMST) approach. This approach helps in finding the alternate link whenever it fails due to various situations and also an improved-handoff (Imp-Handoff) algorithm to support the node failure to the fault tolerance. Improved QMST uses the artificial bee colony (ABC) algorithm to find an alternate edge in place of the broken or failed edge in the spanning tree, in order to improve the fault tolerance in WSN. Imp-Handoff suggests a novel way to find the faulty node owing to less battery power and replaces a defective node by an appropriate neighbor to shift the tasks performed by a faulty node in WSN. Simulation results clearly state that as compared to the basic techniques i.e. Q-MST and Handoff algorithm, the proposed NLFFT model improvises the performance of WSN around by 7%. The results prove that the Imp-QMST gives about 6% improved throughput, 5% less end-to-end delay, and 6% less power consumption than the QMST algorithm. Similarly, Imp-Handoff improves about 4% throughput, 6% less end-to-end delay, and utilizes 7% less power consumption.

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Recently, great attention has been paid to the development of earth rich and nonhazardous Copper Zinc Tin Sulfide (CZTS-Cu 2 ZnSnS 4 ) thin films for application in photovoltaic devices owing to its high absorption coefficient over the visible and infrared region. However, sulfurization process is an indispensable step in growing stoichiometric thin film using conventional physical vapor deposition. Hence, it is imperative to devise a liquid based technique without intentional sulfurization for the optimum quality growth of CZTS thin films. In the current work, layer-bylayer sol-gel deposition technique was utilized to grow high quality CZTS thin films without sulfurization and their structural and optical characteristics were investigated using XRD studies and UV-visible spectroscopy respectively. The morphology and chemical composition of the prepared CZTS films are estimated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis respectively.Highly absorbing and crystalline CZTS films have been successfully grown in the present work which could be further utilized as an absorber layer in photovoltaic applications. K E Y W O R D SCZTS, nontoxic, SEM, sol-gel, UV-visible, XRD | 1195 AMRIT eT Al.

WSNs can be considered a distributed control system designed to react to sensor information with an effective and timely action. For this reason, in WSNs it is important to provide real-time coordination and communication to guarantee timely execution of the right actions. In this paper a new communication protocol RRRT to support robust real-time and reliable event data delivery with minimum energy consumption and with congestion avoidance in WSNs is proposed. The proposed protocol uses the fault tolerant optimal path for data delivery. The proposed solution dynamically adjust their protocol configurations to adapt to the heterogeneous characteristics of WSNs. Specifically, the interactions between contention resolution and congestion control mechanisms as well as the physical layer effects in WSNs are investigated.