Indian Institute of Technology Delhi

About: Indian Institute of Technology Delhi is a education organization based out in New Delhi, India. It is known for research contribution in the topics: Photovoltaic system & AC power. The organization has 11679 authors who have published 26945 publications receiving 503855 citations.

Performance of Elliptical Pin Fin Heat Exchanger with Three Elliptical Perforations

Abstract: A computational investigation has been carried out to assess the heat transfer and pressure drop characteristics of elliptical pin fins arranged in a rectangular duct in a staggered manner. Two types of elliptical pin fins have been considered for this purpose, namely, solid elliptical and perforated elliptical pin fins. Three perforations of elliptical cross sections are considered in the elliptical pin fins. Pressure, temperature and velocity profiles at different locations within the computational domain are considered for different inlet velocities. The heat transfer and pressure drop characteristics along the computational domain are presented and the overall performance, which is defined here as the heat transfer per unit pressure drop, of the heat exchanger is also assessed. The results show that the perforated elliptical pin fins perform better than the solid elliptical pin fin both in terms of heat transfer and pressure drop characteristics.

Synthesis of rattle-type Ag@Al 2 O 3 nanostructure by laser-induced heating of Ag and Al nanoparticles

Abstract: A simple and flexible method has been presented for the fabrication of rattle-type Ag@Al2O3 nanostructures in water and polyvinyl pyrrolidone polymer solution based on laser-induced heating of mixture of silver (Ag) and aluminium (Al) nanoparticles by 532-nm laser. Silver and aluminium nanoparticles were prepared by pulsed laser ablation in liquid using same laser wavelength. The transmission electron micrographs revealed morphological changes from sintered-/intermediate-type structure in water medium and jointed structure (heterostructures) in polymer solution to rattle-type structure with changing irradiation time. At longer irradiation time, the Kirkendall effect becomes dominant due to diffusion rate mismatch between the two metals at the interface and facilitates the formation of porous alumina shell over silver core. The morphology and chemical composition of the nanostructures were characterized by transmission electron micrograph, high-resolution transmission electron micrograph and energy-dispersive X-ray analysis. The melting response of alumina (Al2O3), aluminium and silver nanoparticles with 532-nm laser wavelength provides novel pathway for rattle-type formation.

Integration of Nanometer-Thick 1T-TaS2 Films with Silicon for an Optically Driven Wide-Band Terahertz Modulator

Abstract: The amplitude of terahertz (THz) waves is modulated optically by a pumping laser source, and the effect of optical power on modulation depth is systematically investigated in this work. The reporte...

Information Sets and Information Processing

Abstract: The area of image processing has made rapid strides because of enormous applications it has in different fields. This growth can also be attributed to the increasing use of fuzzy logic in all tasks of image processing as the fuzzy logic facilitates the representation of inherent uncertainty in the image information which can be local or global. For problems like enhancement global information is of interest whereas the local information is needed for the problems of edge detection, segmentation, and recognition. However we need both for the noise removal. The images are of varied types: Medical images (CT scans, MR, X-rays, ECG, etc.), satellite images, natural scenes, videos, games, multimedia, biometrics, industrial, astronomical so on and so forth. The approaches to tackle different images have to be different. For example skin texture can’t represented by a colour model. Defence Science Journal, 2011, 61(5), pp.405-407 , DOI:http://dx.doi.org/10.14429/dsj.61.1192

Preparation and Characterization of Petroleum Sulfonate Directly from Crude

Abstract: Sulfonate surfactants used in enhanced oil recovery (EOR) need not be very pure, such as linear alkyl benzene sulfonate, but should be similar in terms of surface activity. The possibility of preparation, isolation, and purification of petroleum sulfonate directly from crude is studied in the lab. Crudes chosen in this study are GSPC and Panna supplied by Oil and Natural Gas Corporation (ONGC), India. Crude is digested with sulfuric acid (98%) or oleum (20%) for sulfonation and then neutralized with sodium hydroxide. Finally, sulfonate surfactant is isolated and purified by a series of solvent extraction procedures using alcohols and alkanes. The sulfonate surfactant obtained is characterized with respect to EOR applicability, e.g., surface tension measurement and interfacial tension measurement against benzene. The dosing of the sulfonating agent was verified to study its effect on yield of sulfonate and surface tension value. The yield of sulfonate increases with the increase in dosing of the s...