Jadavpur University

About: Jadavpur University is a education organization based out in Kolkata, India. It is known for research contribution in the topics: Population & Fuzzy logic. The organization has 10856 authors who have published 27678 publications receiving 422069 citations. The organization is also known as: JU & Jadabpur University.

Self‐poled Efficient Flexible “Ferroelectretic” Nanogenerator: A New Class of Piezoelectric Energy Harvester

Abstract: Superior ferro- and piezo-electret properties in a self-poled, porous hybrid ferroelectretic polymer nanocomposite film for next-generation device paradigms is introduced by in situ generation of platinum (Pt) nanoparticles (NPs) embedded in poly(vinylidenefluoride-co-hexafluoropropylene) P(VDF–HFP). The cooperative functionality between the self-polarized β-phase and the micropores as charge trapping sites is realized by using a simple solvent evaporation method. As a consequence, the resulting film exhibits extraordinary ferroelectretic behavior, as demonstrated by the superior electrical square-shaped hysteresis loop with large remnant polarization (Pr≈61.7 μC cm−2), piezoelectric charge coefficient (d33∼−686 pC N−1), and ultrahigh dielectric properties (er=2678, tan δ=0.79 at 1 kHz). A new type of ferroelectretic nanogenerator (FTNG) is fabricated using a flexible hybrid nanocomposite film that effectively converts the applied mechanical energy into electrical energy upon compressive normal stress (e.g., by actuating with a human finger). The 18 V of the open-circuit output voltage with expected 17.7 μA short-circuit current are generated from the FTNG under 4 MPa of normal stress amplitude. The high piezoelectric energy conversion efficiency (ηpiezo≈0.2 %) of the FTNG shows that the hybrid polymer nanocomposite film is well suited for the next generation of piezoelectric-based energy harvesters. The operation of more than 50 blue LEDs, 25 green LEDs, and several capacitors without any subsidiary batteries is demonstrated using the FTNG.

Anti-inflammatory and related actions of Syzygium cuminii seed extract

Abstract: The chloroform fraction of Syzygium cuminii seeds was found to cause significant inhibition of carrageenin, kaolin and other mediator-induced oedema. The extract inhibited exudation of protein, leakage of dye in peritoneal inflammation and migration of leucocytes. The extract also caused inhibition of grannloma formation, experimental arthritis and also turpentine-induced joint oedema. Significant anti-pyretic action of the extract was also observed against yeast-induced pyrexia. These observations established the anti-inflammatory effect of S. cuminii seed extract in exudative, proliferative and chronic stages of inflammation along with an anti-pyretic action.

Studies on nutritional and oxygen requirements for production of L-asparaginase by Enterobacter aerogenes.

Abstract: The carbon and nitrogen sources most suitable for L-asparaginase production by Enterobacter aerogenes were selected and their concentrations optimized in shake-flask cultures. Sodium citrate (1.0%) and diammonium hydrogen phosphate (0.16%) proved to be the best sources of carbon and nitrogen, respectively. Nitrogen catabolite repression of enzyme formation was absent in this bacterium. Cultivation in a reactor showed that the dissolved oxygen level is the limiting factor for L-asparaginase production by E. aerogenes. Glucose was found to be a repressor of enzyme synthesis. Asparagine was absent intracellularly when the L-asparaginase level was high. An increase in the extracellular alanine level when the dissolved oxygen remained low indicated a shift from aerobic to fermentative metabolism.