National Institute of Technology, Meghalaya

About: National Institute of Technology, Meghalaya is a education organization based out in Shillong, India. It is known for research contribution in the topics: Control theory & Electric power system. The organization has 503 authors who have published 1062 publications receiving 6818 citations. The organization is also known as: NIT Meghalaya & NITM.

Optical studies of a binary liquid crystal mixture exhibiting induced smectic A phase

Abstract: A binary liquid crystalline mixture of a monotropic polar compound 4-cyanophenyl 4′-n-pentyl benzoate (CPPB) and an enantiotropic non-polar compound 4-n-hexyl phenyl 4-n′-pentyloxy benzoate (ME5O.6) shows the presence of an induced smectic A phase in the region 0.1 ≤ x CPPB ≤ 0.82, where x CPPB is the mole fraction of CPPB. The results of texture study, density study and refractive index measurements of the eutectic mixture along with those of the pure samples are reported in this paper. The density values of the eutectic mixture are found to be much higher than that of the pure samples. The determination of order parameters of the pure samples and eutectic mixture has been carried out. In order to determine the order parameters of the samples, we have used different methods, Vuks’, Neugebauer’s, modified Vuks’ and direct extrapolation method. The results of order parameters obtained from the different approaches are compared and analysed in detail.

Experimental investigation of friction stir welding of PLA

Abstract: Friction stir welding (FSW) is a solid-state welding technology which is frequently used for welding of thermoplastic and metallic alloys in the automobile and aerospace industries. Polylactic acid (PLA) is a biodegradable thermoplastic polymer. PLA can replace petroleum-based polymer in many applications if the FSW process can be used for welding of PLA-based engineering components. In the present study, FSW process was carried out to join PLA sheets to investigate the influence of input parameters such as tool speed and transverse speed on the tensile strength of the welded specimens using different pin profiles. The tool speeds of 700, 1400, and 2000 rpm and traverse speeds of 20, 30, and 40 mm/min were selected to perform the welding. The pin profiles such as cylindrical, threaded, and conical pins of the tool were used to study their effect on the joint strength and efficiency. Visual inspection of the welded specimens was carried out to find the defects in welding. The temperature that is induced during welding and the load-displacement behavior of the welded specimens were also studied to understand the welding behavior of biodegradable PLA.

A QoS-aware dynamic bandwidth allocation scheme for multi-hop WiFi-based long distance networks

Abstract: In this paper, we propose a QoS-aware dynamic bandwidth allocation scheme to mitigate congestion problem in gateway-based multi-hop WiFi-based long distance networks and thereby enhance QoS guarantees for real-time traffic. It presents a dynamic slot scheduling scheme which efficiently distributes the unused TDMA time slots among the needy nodes. The distribution process is carried out in a hierarchical manner through the use of parent-child relationship of a tree topology. By doing so, end-to-end performance of real-time traffic is enhanced manifold. Furthermore, the proposed protocol provides assured packet forwarding for already admitted flows by allowing transmission of nodes according to the capacity of ancestral links. Simulation results show that the proposed protocol achieves a significant performance improvement in terms of throughput and delay of real-time traffic.

Designing an optimized model-free controller for improved motion tracking by rugged electrohydraulic system

Abstract: Electrohydraulic actuation systems with proportional valves and industry-grade cylinders have widespread use due to their low cost and ease of maintenance. Achieving good tracking of output positio...