Dr. Nandini R Nadar
@bmsit.ac.in
Assistant Professor, Department of Mechanical Engineering
BMS Institute of Technology and Management
An down to earth person with a passion towards research and teaching to uplift the students and to improve our country technically for the benefit of human mankind. My current research focus is on development of lead free piezoelectric materials for various electronic devices such as energy harvesting, actuator, sensor and transducers. I am interested in developing lead-free functional materials and devices. In this regard i am interested in collaborating with scientists/academicians from different disciplines for the benefit of society and piezoelectric market of today's world.
EDUCATION
B.E - Industrial Production
M.Tech - Product Design & Manufacturing
PhD - Mechanical Engineering Sciences - Advanced Functional Materials- Smart Materials - Lead free piezoelectric materials- Energy Harvesting- Sensors-Transducer applications.
RESEARCH INTERESTS
Advanced Functional Materials, Nano Science & Nano Technology, Micro and electro fabrication techniques, lead free piezoelectric materials,
Self healing materials, Shape memory polymers , Adanced Ceramics
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Nandini R Nadar, M Krishna, and A V Suresh
Springer Science and Business Media LLC
The objective of this research work is to investigate the effect of multiwall carbon nanotube (MWCNT) content (0.3–1.2 wt%) on a potassium sodium niobate (KNN)-based piezoelectric unimorph harvester for enhancing the energy generation capacity. KNN–MWCNT composites were fabricated by using a microwave solid state technique. The energy-harvesting performance of the KNN–MWCNT composite was determined by the base excitation method and sized to resonate between 20 and 100 Hz at 1 $$\\hbox {M}\\Omega $$MΩ load resistance. The energy performance of the KNN composite at percolation threshold (0.6 wt% MWCNT) showed a maximum power generation of $$2.94\\, \\upmu \\hbox {W}$$2.94μW, the power density of 7.15 $$\\upmu \\hbox {W}$$μW$$\\hbox {m}^{-3}$$m-3 and overall efficiency of 83.75% at an input acceleration of 0.5 g and a load resistance of 1 $$\\hbox {M}\\Omega $$MΩ. Improvements observed in the power generation by percolation phenomena and ionic flow over the nanotube surface of KNN composites prove to be a boon for low-power sensing devices.Graphic abstract
M. Krishna, R. Nandini, A. Suresh and K. N. Rao
An intense research on lead free piezo-electric ceramics is being carried out worldwide for more than a decade due to environmental concern and toxicity of lead-based ceramics [1-2]. Investigation based on alkali niobates (ANbO3) has gained momentum in recent times. The general form of these lead-free perovskite materials is ANbO3 [3]. Potassium niobates (KNbO3) exhibited greater piezo-electric properties, which are stable along the non-polar crystallographic directions than along the polar axis and exhibits stable orthorhombic phase over a wide temperature range [4-6]. It has high piezoelectric coefficient among the lead free based piezo materials. KNbO3 is extensively used in amalgamation with sodium niobates (NaNbO3) as a binary system which makes it one of the most promising lead-free piezoelectric materials. It is a combination of ferroelectric (FE), KNbO3 and an anti-ferroelectric (AFE) NaNbO3. Ferroelectricity is reported to be up to 90% in KNbO3 in the binary system of KNbO3-NaNbO3[7]. Based on a study on various stoichiometric ratios, it was observed that the composition K0.5Na0.5NbO3 (KNN) was favorable, and the composition (50/50) is in between two orthorhombic phases at morphotropic phase boundary (MPB) as observed in lead zirconate titanate (PZT) [8]. Potassium sodium niobate (KNN) is satisfactorily recommended for a broad range of applications due to its high Curie temperature (Tc) of 420 °C and a low density of 4.51 g/cm3[9]. The Conventional solid-state route, wet chemistry methods such as sol-gel, hydrothermal has been applied for synthesis of KNN nano-size powders [10-13]. Sol-gel and solid-state synthesis of KNN ceramics have drawn much interest due to its ability to obtain nano-size powders. The hydrated carbonated phases formed during sol-gel process needs high temperature (near melting point ~1140 °C) to decompose and this increases the volatile behavior of alkaline elements of KNN [11,12]. The use of soft chemistry though reduced the synthesis temperature overcoming volatile behavior of alkaline elements but could not avoid the presence of carbonates during heat treatment, there by showing the need for high temperature [11,12]. Since solid state route can easily decompose oxides and carbonates, it is extensively used to synthesize ferroelectric Abstract: An efficient solid-state approach was established to synthesize (K0.5Na0.5) NbO3 ceramics using calcination kinetics and microwave assisted sintering. Milling of carbonate and oxide raw materials were carried out for 15 h to obtain homogeneous nano particles. The crystallite size of 5.30 nm was obtained for the KNN system after calcination through optimized parameters and observed to be stoichiometric in nature. The obtained nano particles showed phase transition from orthorhombic to tetragonal crystal structure without any secondary phases. The high relative density and tetragonality ratio of KNN ceramics obtained through optimized sintering parameters yielded with significant piezoelectric and ferroelectric properties.
R. Nadar Nandini, M. Krishna, A.V. Suresh, and H.N. Narasimha Murthy
Elsevier BV
Abstract The aim of the research work was to investigate the effect of multiwall carbon nanotubes (MWCNTs) reinforcement (0.3–1.2wt.%) on functional properties of microwave sintered Potassium sodium niobate (KNN) composites. Sintered composites are characterized for crystal structure, morphology and temperature stability of piezo-electric, ferroelectric and dielectric properties. KNN composites showed perovskite phase with improved tetragonal symmetry, fine grained porous microstructure, reduced dielectric loss and enhanced effective permittivity. The optimum functional properties and thermal stability obtained for KNN-MWCNT (0.9 wt.%) composites over the range of 20–100 °C, makes the idea of using the addition of MWCNTs to KNN ceramics an interesting approach in searching new structures for temperature stability.
RECENT SCHOLAR PUBLICATIONS
MOST CITED SCHOLAR PUBLICATIONS
GRANT DETAILS
Seed Money for project titled “Development and Analysis of Lead-Free Piezoelectric Material for Pressure Sensor” under COE (TEQIP 1.2.1) was conveyed for a grant of at RVCE, Bangalore.
RESEARCH OUTPUTS (PATENTS, SOFTWARE, PUBLICATIONS, PRODUCTS)
Patent
Multi-Walled Carbon Nano-tube Reinforced Lead-free KNN Piezoelectric Ceramic Materials (C.000321), Date of Filing: 30/08/2016. Application Number: 201641029478, Publication Date: 9/03/2018, Request for Examination date: 15/02/2017.
Status: Application Awaiting Examination
Commercialization
Presentation on MWCNT Reinforced KNN based Pietro-electric materials for energy storage devices were given to ELPRO ENERGY DIMENSIONS (P) LTD, for commercialization of the patent work.
Industry, Institute, or Organisation Collaboration
Performing Collaborative work with Dr. Anidya Deb, Professor, Center for Product Design & Manufacturing, IISC ,Bangalore.
Performing Collaborative research work with Dr. P.K.Panda, Head , Material Science Division, CSIR-NAL, Bangalore.
INDUSTRY EXPERIENCE
Worked as executive engineer in stock holding corporation india limited, Mumbai in the field of oracle and D2K forms
SOCIAL, ECONOMIC, or ACADEMIC BENEFITS
Working on lead free piezoelectric materials and lead free batteries will be really benefited to our society as it is Eco friendly. Secondly as we are making MAKE IN INDIA project it helps to improve the economy of our country. Thirdly it provides wide scope of research for academicians, scientist and researchers to grow our nation technically in an go green concept.