National Institute of Technology Calicut

About: National Institute of Technology Calicut is a education organization based out in Kozhikode, Kerala, India. It is known for research contribution in the topics: Computer science & Control theory. The organization has 3627 authors who have published 4638 publications receiving 50830 citations. The organization is also known as: Calicut Regional Engineering College & NIT Calicut.

Experimental investigations on diethyl ether as fuel additive in biodiesel engine

Abstract: In this work, biodiesel (methyl esters) is produced from unrefined rubber seed oil by two-step transesterification process Biodiesel engines are prone to cold-starting problems in winter seasons and emit more nitrogen oxides To overcome these problems, diethyl ether is used as a fuel additive for biodiesel The lower percentage addition of diethyl ether with biodiesel improves the engine performance and emission characteristics The experimental results support that diethyl ether can be used as an additive with biodiesel to improve the performance and emission characteristics

Enhanced nonlinear optical properties of ZnS nanoparticles in 1D polymer photonic crystal cavity

Abstract: The enhanced nonlinear optical absorption and optical limiting properties of polymeric one dimensional photonic crystal (1DPhC) with ZnS nanoparticles as defect are reported. The 1DPhC was fabricated by spin coating technique, using polystyrene (PS) and cellulose acetate (CA) as high and low refractive index materials. ZnS nanoparticles were synthesized in CA solution by laser ablation technique and the structural, morphological and non linear optical characterizations were done. A microcavity structure with cavity resonance around 532 nm was designed by inserting ZnS NPs/CA defect layer between two Bragg reflectors comprising 10 bilayers of CA/PS. A significant enhancement (4.6 times) in both nonlinear absorption and optical limiting properties of 1DPhC with ZnS defect layer was observed under 532 nm pulse excitation compared to the ZnS reference sample. The enhancement in the observed nonlinear optical properties of the system could be accredited to the confinement of optical field due to the localization of photons in the cavity mode. The current system can play crucial roles in designing practical nonlinear optical devices, such as optical limiters, optical switchers etc.

Synthesis, structure, photophysical, electrochemical properties and antibacterial activity of brominated BODIPYs

Abstract: A series of mono- and di-brominated BODIPYs (1–5) was synthesized and characterized with a view to study the performance of dyes towards antibacterial activity. Regioselective bromination at the 2- and 2,6-positions of the BODIPY core was achieved with quantitative yield. The bromination of meso-(4-hydroxyphenyl) BODIPY (5) yielded an unexpected dibromo derivative, where the bromine groups were installed at the 3,5-positions of the phenyl ring rather than the 2,6-positions of the BODIPY core, which is confirmed and supported by UV-visible, fluorescence, and 1H NMR spectroscopic analyses, electrochemical studies, and also by single crystal X-ray crystallography. We observed a red shift of ∼16 nm in the absorption and 20–29 nm in the emission spectra in CH2Cl2 for the installation of each bromine group at the BODIPY core. The small difference between the first reduction potentials of the parent and dibromo derivative (5 and 5b) reveal that dibromination does not occur on the pyrrolic moiety. The intermolecular interactions involving C⋯H, F⋯H, H⋯H, and Br⋯H are the key factors in stabilizing the molecular crystal packing. The antibacterial properties of these dyes were investigated and the brominated derivatives showed better antibacterial effects than their corresponding parent BODIPYs, particularly the unusual dibromo derivative, 5b.