Kamal Prasad

Lactobacillus assisted synthesis of titanium nanoparticles

An eco-friendlylactobacillus sp. (microbe) assisted synthesis of titanium nanoparticles is reported. The synthesis is performed at room temperature. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of Ti nanoparticles. Individual nanoparticles as well as a number of aggregates almost spherical in shape having a size of 40–60 nm are found.

Structural and Dielectric Properties of ZnO Added (Na1/2Bi1/2)TiO3 Ceramics

Structural and dielectric properties of polycrystalline samples of lead-free (1-x)(Na1/2Bi1/2)TiO3-xZnO, prepared using a high-temperature solid-state reaction method, were investigated in the composition range of 0≤x≤0.10. Rietveld analyses of X-ray diffraction data indicated the formation of a single-phase hexagonal structure with R3c symmetry. Williamson-Hall approach was applied to estimate the apparent particle size and lattice strain of the compounds. Temperature dependence of dielectric constant showed that the addition of ZnO to (Na1/2Bi1/2)TiO3 shifted the phase transition temperature towards higher side, a property favourable for practical applications of these ceramics. Further, temperature dependent permittivity data provided low temperature coefficient of capacitance (Tcc

Green synthesis and characterization of BaFe0.5Nb0.5O3 nanoparticles

A green, low-cost, and reproducible Lactobacillus sp. assisted biosynthesis of BaFe0.5Nb0.5O3 nanoparticles is reported. X-ray diffraction (XRD), vibration sample magnetometer, and transmission electron microscopy analyses are performed to ascertain the formation of BaFe0.5Nb0.5O3 nanoparticles. XRD analysis of the compound indicated the formation of a single-phase cubic structure. Individual nanoparticles as well as a few aggregates having the size of 20–60 nm are found. A possible involved mechanism for the biosynthesis of nano BaFe0.5Nb0.5O3 has also been proposed in which reactive oxygen species as well as partial pressure of gaseous hydrogen (rH2) of the culture solution seems to play an important role in the process. Magnetic studies have been carried out using vibration sample magnetometer, which indicated the possibility of magneto-electric coupling.

Electrical Conduction in Ceramic by Complex Impedance/Modulus Spectroscopy

The present work describes the piezoelectric, impedance, and conductivity studies of ; BNT-BT ceramics. The ceramics were prepared by conventional ceramic fabrication technique. X-ray diffraction data confirmed the formation of a pure compound in all the compositions. Williamson-Hall plot yielded the apparent crystallite sizes ~26–52 nm, and SEM micrograph showed grain sizes ranging between 1.8–3.5 μm for the material samples. Values of longitudinal piezoelectric charge coefficients of the samples poled under a dc electric field of about 2.5 kV/mm at 80°C/15 min indicated that their piezoelectric properties near the MPB are rather sensitive to the phase composition and reach preferred values at , where the relative content of the tetragonal phase is significantly higher than that of the monoclinic phase. Complex impedance/modulus spectroscopic analyses indicated the presence of grain-boundary effect along with the bulk contribution and also confirmed the presence of non-Debye type of multiple relaxations in the materials. The temperature dependent electrical conductivity data suggest the negative temperature coefficient of resistance behaviour. The activation energy studies allow insight into the nature of the conduction mechanisms occurring in the materials system which are explained on the basis of hopping model of charge carriers.

Electrical conduction in (Bi0.5Na0.5)0.94Ba0.06TiO3-PVDF 0-3 composites by impedance spectroscopy

The present work describes the use of ac complex impedance and electric modulus spectroscopy techniques to obtain the electrical parameters like electrical conductivity and activation energy of (Bi0.5Na0.5)0.94Ba0.06TiO3 (BNBT06)-PVDF 0-3 composites with (a) 10, (b) 20 and (c) 30 vol. percentage of BNBT06 in the frequency range 100 Hz-5MHz over a temperature range of 35 o C-150°C. SEM micrographs showed almost homogeneous distribution of grains with less porosity for all the compositions and the EDAX patterns confirmed the presence of different constituent elements of the composite samples. Complex impedance spectroscopic analysis indicated the presence of non-Debye type dielectric relaxation in the composites. The bulk resistance showed the NTCR character of the composite materials and the presence of grain-boundary effect along with the bulk contribution, especially in the lower frequency and higher temperature regime, was indicated by the modulus spectroscopic analyses, thus confirming the non-Debye type of multiple relaxations in the system. The ac electrical conductivity data as a function of temperature also endorsed the NTCR character of BNBT06-PVDF 0-3 composites. The ac conductivity based activation energy data allowed insight into the mechanism of the occurring conduction processes in the composite system which are explained on the basis of hopping model of charge carriers. Keywords- Ceramic-polymer 0-3 composites; Grains /grain-boundaries; Hopping conduction; Complex impedance/ modulus spectroscopy; Ac conductivity; Activation energy

Understanding Mechanism of Fungus Mediated Nanosynthesis: A Molecular Approach

The chapter details different processes of biosynthesis of inorganic (metallic and oxide) nanoparticles mediated by the different members of fungi. The biosynthetic mechanism (at molecular level) has been discussed in detail. The nanosynthesis is broadly dependent upon the modulation of key parameters like temperature, pH and other medium conditions. It is conclusively found that although, the cellular level organization matters along with their metabolic fluxes/signal transduction pathways, it is the different stress shearing cues at different levels (ranging from cell wall to nucleus) that bestows a unique echelon to an individual genera in the phylogeny.

Nanomaterials: An Upcoming Fortune to Waste Recycling

Towards an inclination to recycle waste, the chapter articulates on the prevailing performance of nanotechnology in waste pursuit. The classification of waste, multifold waste management techniques, nanotechnology role in waste management followed up by waste conversion to valuable products, finishing with the application of the nanomaterial procured from waste have been confabulated. The chapter categorizes nanomaterial fabrication from garbage, combustible waste, ash, pharmaceutical waste, agricultural waste, and microbial biomass which in turn imparts reduced possession on conventional method of waste conversion to valuable products. Significant research attempt on nanoconversions from waste are still performed at laboratory scale. Although nanotechnology proved to be an upcoming potential technique in waste conversion to valuable products but in real picture, the technologies will worth more if it combats inadequacy in scale up of waste mediated nanoconversion.

Hidden Treasures for Nanomaterials Synthesis

This chapter focuses on the novel routes for biosynthesis of inorganic (metal and oxide) nanoparticles by using plant extract as a resource. The mechanism of biosynthesis/green synthesis has been discussed. The nanosynthesis for different nanoparticles has been depending on the various key parameters like kinetics of reaction, pH, temperature, concentration, agitation rate, and other medium. The procedure for plant based nanosynthesis has been delineated. It is found that the cellular level organization along with their metabolic fluxes/signal transduction pathways of living system plays important role in nanosynthesis. In this chapter, plant as a source contains primary and secondary metabolites for nano-transformation.

Nanofabrication by Cryptogams: Exploring the Unexplored

This chapter attempts to explore cryptogams, the salient members of plant diversity as tools for nanofabrication. It presents an overview about cryptogams, its phylogeny, and role in plant diversity along with its ethnomedicine properties. The cryptogams have been gifted with immense reservoir of active metabolites having bio-reductive and pharmacological potentials. Therefore, the chapter describes the various possibilities and benefits with intent to draw attention towards these members for nanofabrication explorations. It further attempts to decipher the fundamental science behind the fabrication and summarizes the various pharmacological applications.

Plants as Fabricators of Biogenic Platinum Nanoparticles: A Gambit Endeavour

The chapter presents a synoptic overview of fabrication of platinum nanoparticles and envisages the importance and benefits of plant-mediated fabrication of biogenic platinum nanoparticles. It summarizes the up-to-date advances in the fabrication of platinum nanoparticles by plants and other biological sources, and highlights as to why plants as fabricators of biogenic platinum nanoparticles have drawn an unequivocal attention. It focuses on the possible benefits of employing plants in comparison to other biological sources and critically discusses the underlying bioreductive mechanism.