Indian Institute of Technology Bombay

About: Indian Institute of Technology Bombay is a education organization based out in Mumbai, India. It is known for research contribution in the topics: Population & Thin film. The organization has 16756 authors who have published 33588 publications receiving 570559 citations.

Novel and efficient MR active aqueous colloidal Fe3O4 nanoassemblies

Abstract: This work demonstrates a new class of magnetic resonance (MR) active aqueous Fe3O4 magnetic nanoparticle nanoassemblies (Fe3O4 MNNA) of ∼40 nm size comprising ∼6 nm particles. They exhibit enhancement in T2 MR contrast as compared to 6 nm isolated counterparts (Fe3O4MNP) and commercial contrast agent, ferumoxytol. This significant improvement in the T2 MR signal arises from the synergistic magnetism of multiple Fe3O4nanoparticles assembled in Fe3O4 MNNA. These nanoassemblies also show better colloidal stability, higher magnetization, good specific absorption rate (under external AC magnetic field) and cytocompatibility with cells. Further, the functional groups (–NH2) present on the surface of Fe3O4 particles can be accessible for routine conjugation of biomolecules through well-developed bioconjugation chemistry. Specifically, a new MR active colloidal amine-functionalized Fe3O4 nanoassembly with enhanced T2 contrast properties has been fabricated, which can also be used as an effective heating source for hyperthermia treatment of cancer.

Novel High-Performance Stand-Alone Solar PV System With High-Gain High-Efficiency DC–DC Converter Power Stages

Abstract: This paper proposes a novel 3 $\phi$ stand-alone solar photovoltaic (PV) system configuration that uses high-gain high-efficiency $(\approx\! 96\%)$ dc–dc converters both in the forward power stage and the bidirectional battery interface. The high-voltage-gain converters enable the use of low-voltage PV and battery sources. This results in minimization of partial shading and parasitic capacitance effects on the PV source. Series connection of a large number of battery modules is obviated, preventing the overcharging and deep discharging issues that reduce the battery life. In addition, the proposed configuration facilitates “required power tracking (RPT)” of the PV source as per the load requirements, eliminating the use of expensive and “difficult to manage” dump loads. High-performance inverter operation is achieved through $abc$ to $dq$ reference frame transformation, which helps in generating precise information about the load's active power component for RPT, regulation of ac output voltage, and minimization of control complexity. Inverter output voltage is regulated by controlling the modulation index of sinusoidal pulsewidth modulation, resulting in a stable and reliable system operation. The active power demand is controlled by regulating the dc link voltage. All the analytical, simulation, and experimental results of this work are presented.