Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

&nbsp;

&nbsp;

VIT University

This paper investigates the performance of W-Ni-Cu heavy alloy with 0.5, 1.0, 1.5 and 2.0 wt% of cobalt addition. The alloys are prepared through spark plasma sintering (SPS) at a sintering temperature of 1400°C following a heating step of 100°C/min. The alloy with 0. 5 wt% cobalt is observed to have good mechanical properties in comparison with other alloys. The density and hardness of the alloys follow a decreasing trend with an increase in cobalt addition. Subsequently, the microstructural characteristics such as contiguity, average grain size and matrix volume fraction are measured and investigated, as they are found to affect the mechanical properties of the alloys. The average grain growth of the alloys varies around 13 µm. As the cobalt percentage is increased, W-W contiguity is observed to increase. The W-Ni-Cu-0.5Co alloy exhibits higher yield and tensile strength in comparison with other heavy tungsten alloys. The fracture surface analysis showed predominantly tungsten grain cleavage fracture for 0.5 wt% Co alloy. The other alloys showed more features of matrix interface failure and tungsten decohesion. © 2019 ICE Publishing: All rights reserved.

Department of Design and Automation

School of Mechanical Engineering

Vellore Campus

Mechanical

Chennai Campus

Emerging Materials Research

Effect of cobalt addition on the morphology and mechanical properties of W–Ni–Cu–Co alloy

The last few decades has seen good advancement in the design and use of docking systems for several fields including space. The present work involves designing a docking system that can operate between two underwater vehicles. Submarines are chosen as test vehicles and the system is designed to transfer physical and material goods between two submarines. The vehicles considered for the analysis are of same type with hatches attached to its left and right surfaces. Structural and fluid flow analyses are carried out on the designed docking system to ensure its stability under the action of water pressure. The pressure and velocity of the ocean currents at a particular depth of 250m are considered for the analysis. The variation of stresses across the docking system is recorded and the maximum deformation is found to be negligible. The pressure distribution and velocity variations are also analyzed and the results are found to be satisfactory. © 2018 Elsevier Ltd.

VIT Unitversity

Materials Today: Proceedings

Design and Analysis of Underwater Docking System

Agriculture is the major sector in the world that plays a vital role in developing the economy of a nation. Agro technology is the process of implementing the recent technologies to develop the crops that are being produced. The use of agro technology not only helps in improving the efficiency of the crop that are being produced but also helps in developing devices that are suitable for doing mechanical works in the fields. This results in minimization of the total cost of production, saving of time and reduction in the effort involved in the process. The new technology should also be economically feasible and hence the behavior of the technology and its role in the society is an important consideration before developing a new product or process. In this work a seed sowing machine has been developed that help the farmers in harvesting the best crop with least efforts. A mechanical device that helps in sowing operation and controlled using IoT (Internet of Things) has been developed. © IAEME Publication.

World University root node

International Journal of Mechanical Engineering and Technology

Fabrication and automation of seed sowing machine using IoT

The effect of cobalt (0.5 wt%, 1.0 wt%, 1.5 wt% and 2.0 wt%), as an alloying element, on the microstructure and mechanical properties of W-Ni-Fe tungsten heavy alloy (WNF) prepared through spark plasma sintering (SPS) process is investigated in this work. The sintering is performed at 1400 °C with a heating rate of 100 °C/min and holding time for a period of 2 min. The properties of the cobalt added heavy alloys (WNFC) are found to be superior to that of the tungsten heavy alloy without cobalt addition. The 1.0% cobalt alloy is observed to give higher yield and tensile strengths compared to other alloys. As the mechanical properties of the alloys depend on the microstructural features, a detailed study on the influence of the microstructural parameters such as average grain size, contiguity and matrix volume fraction on the properties of the alloys is carried out. The average tungsten grain size of WNF alloy is 12.3 µm and that of WNFC alloys is from 9.5µm to 11.5 µm. The control of grain size is significantly evident in the case of spark plasma sintered alloys. The yield strength is found to be influenced by the W-grain size of the microstructure. The contiguity of the WNFC alloys is observed to decrease with increase in percentage of cobalt addition. The fractograph analysis of the tensile tested specimen helps in understanding the tensile behaviour of the alloys. The WNFC alloys show predominantly W-grain cleavage fracture compared to the WNF alloy, possibly due to the good cohesive strength of the matrix phase and W/matrix interface, because of cobalt addition and also due to the high heating rate followed in the SPS process. © 2017 Elsevier B.V.

Materials Science and Engineering: A

Microstructure and mechanical properties of spark plasma sintered tungsten heavy alloys

There is a continuous effort in reducing the sintering temperature and sintering time for synthesizing tungsten samples using different approaches. In this paper, spark plasma sintering (SPS) technique is used to consolidate pure tungsten of 10 micron average particle size at a lower temperature of 1200°C. For comparison, the tungsten compact is also sintered in a conventional furnace under vacuum condition. The microstructures of the samples sintered by both the processes indicate partial sintering of tungsten. The density, hardness and grain size measurements are recorded for the sintered samples and the results are compared for both sintered processes. The densities of the tungsten samples sintered through spark plasma sintering and conventional sintering are found to be 66.79 g/cm3 and 68.26 g/cm3 respectively. The hardness values follow the same trend as found in sintered density values. The average grain diameter of the tungsten grain does not show much variation between the processes. © 2017 Elsevier Ltd.

Synthesis of tungsten through spark plasma and conventional sintering processes

Tungsten is a refractory metal possessing good mechanical properties of high strength, high yield point, and high resistance to creep. Therefore, tungsten and its alloys are used in many high temperature applications. Due to the high melting point, they are generally processed through powder metallurgy method. The powders are compacted using die pressing or isostatic pressing. The compacts are sintered in a sintering furnace to achieve high density, thereby, making the metal suitable for further processing. This article reviews the recent research findings of consolidating tungsten and its alloys (W–Ni–Fe and W–Ni–Cu), from preparation of powder alloys to sintering of the compact. The advances in sintering are based on the objective of achieving good densification of the metal at lower temperature and at faster rate. The use of microwave sintering and spark plasma sintering techniques resulted in significant reduction in sintering time and producing products of good mechanical properties. © 2016, The Indian Institute of Metals - IIM.

Transactions of the Indian Institute of Metals

Sintering of Tungsten and Tungsten Heavy Alloys of W–Ni–Fe and W–Ni–Cu: A Review

The sintering temperature of pure tungsten can be reduced through the addition of small amounts of transition elements. The present study deals with the activated sintering of tungsten with 1.0 wt% additions of copper, cobalt, molybdenum, iron and nickel using the spark plasma sintering (SPS) technique. The alloys were sintered at 1200°C and the mechanical properties and microstructures were compared with those of conventionally sintered alloys, sintered under vacuum condition. The high-rate sintering of SPS has led to an overall reduction in process time and also to a better densification of alloys compared with the conventional sintering process. In both the processes, nickel addition is found to be the best activator, followed by cobalt, iron, molybdenum and copper. The addition of copper and molybdenum showed only a meager increase in the relative density. The alloys, with nickel, cobalt and iron additions, sintered through the SPS process offered much higher density compared with the conventionally sintered alloys. The highest density is observed for the nickel-doped tungsten alloy, which is found to be around 90% of the theoretical density. The microhardness of the sintered alloys is found to depend on its sintered density. © 2017 Taylor & Francis.

Materials and Manufacturing Processes

Activated sintering of tungsten alloys through conventional and spark plasma sintering process

Interest in electromagnetic forming of sheet metals for automotive applications has been growing in recent years, due to its potential to form aluminium and other low formability materials. Further, to achieve the aim of weight reduction, some components are made of perforated sheet metals. The aim of this paper is to study and analyse the two stage electromagnetic forming of perforated aluminium sheet metals with the help of Finite Element method. The Electromagnetic force on the sheet is calculated using Ansys Emag by changing the parameters in current density, gap between coil and sheet, the coil thickness. The force is calculated for nine combinations of the three parameters. Taguchi orthogonal array is used to find the best combination of parameters. Also optimization of parameters controlling the electromagnetic force is found out using ANOVA technique. The obtained force is applied on the sheet and the corresponding deformation of the sheet is obtained using Ansys Structural. © 2014 Published by Elsevier Ltd.

Fulltext

Procedia Engineering

A Two Stage Finite Element Analysis of Electromagnetic Forming of Perforated Aluminium Sheet Metals

Obtaining optimal power flow solution is a strenuous task for any power system engineer. The inclusion of FACTS devices in the power system network adds to its complexity. The dual objective of OPF with fuel cost minimization along with FACTS device location for IEEE 30 bus is considered and solved using proposed Enhanced Bacterial Foraging algorithm (EBFA). The conventional Bacterial Foraging Algorithm (BFA) has the difficulty of optimal parameter selection. Hence, in this paper, BFA is enhanced by including Nelder-Mead (NM) algorithm for better performance. A MATLAB code for EBFA is developed and the problem of optimal power flow with inclusion of FACTS devices is solved. After several run with different initial values, it is found that the inclusion of FACTS devices such as SVC and TCSC in the network reduces the generation cost along with increased voltage stability limits. It is also observed that, the proposed algorithm requires lesser computational time compared to earlier proposed algorithms. © 2013 ISA.

Department of Electrical Engineering

School of Electrical Engineering

Department of Energy and Power Electronics

ISA Transactions

An enhanced bacterial foraging algorithm approach for optimal power flow problem including FACTS devices considering system loadability

All around the globe, various research oriented work is going regarding the optimization of orthogonal frequency division multiplexing (OFDM) for wide range of applications. Coded-OFDM eliminates interference (ISI) and is robust to radio fading channels impairments. Thus OFDM offers higher data throughput with increased reliability in data transmission. Since the Ultra wideband (UWB) spectrum has the unlicensed nature, all wireless devices sharing the spectrum must coexist. According to Multi Band OFDM Alliance (MBOA), multiband OFDM (MB-OFDM) has the advantageous feature of complying with local regulations by dynamically turning off certain tones or channels in software. But disadvantage is the side-band interferences in UWB caused by MB-OFDM. We propose a soft-spectrum adaptation based Detect and Avoid (DAA) mechanism to suppress the undesired interference. Detection technique is based on power spectrum density estimation and Avoidance mechanism is based on sub carrier nullifying using windowing technique. A type of block Turbo code modulation scheme is employed where the side-band interferences are attenuated quickly. Simulation result of soft-spectrum based DAA technique is shown along with SNR performance comparison between coded and uncoded OFDM. © 2013 IEEE.

Department of Communication Engineering

School of Electronics Engineering

2013 International Conference on Communication and Signal Processing

Interference reduction in MB-OFDM ultra wideband systems using Turbo code

WiMAX (Worldwide Interoperability for Microwave Access), a new wireless technology promises to deliver both high data rates and long range coverage. In wireless communication channel, the effect of multipath fading is reduced by the use of OFDM transmissions. Adaptive subcarrier allocation methods exploit the multiuser diversity, which leads to improvement in performance by assigning subcarriers to users based on the channel conditions. In this paper, three algorithms are discussed to achieve bandwidth efficiency and fairness. The two algorithms named, fair allocation, proportional allocations are compared with static multiple access method. Performance is compared in terms of Signal to Noise Ratio (SNR) and throughput. © 2006-2013 Asian Research Publishing Network (ARPN).