M. Muruganandam; P.C. Mukesh Kumar
Abstract
Much research works are being carried out in applications of nanofluids at different engineering fields as they have improved thermal conductivity. However, the effective applications of nanofluids have limitations such as poor stability, sedimentation, erosive wear and potential health risk. In heat ...
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Much research works are being carried out in applications of nanofluids at different engineering fields as they have improved thermal conductivity. However, the effective applications of nanofluids have limitations such as poor stability, sedimentation, erosive wear and potential health risk. In heat transfer application point of view, stability of nanoparticles plays a major functionin enhancing heat transfer. In this experimental investigation, the stability of Multi-walled Carbon Nano Tube (MWCNT)/water nanofluids with surfactant and without surfactant has been carried out by keeping the nanofluids at static condition and at constant temperature at different time interval. The nanofluids were prepared by means of the use of Multi-walled Carbon Nano Tube (MWCNT) as base materials and distilled water as base fluids at 0.1%, 0.3%, 0.5% and 0.7% volume concentration with 0.02% and 0.05% sodium dodecyl butane sulfonate (SDBS) as surfactant and without the surfactant two-step method is used to put together the nanofluids underneathattention. The stability analysis ofpreparednanofluids are studied with the UV-Vis. spectrophotometer, measure of zeta potential value , and photograph capturing techniques by keeping the nanofluids under static condition for The MWCNT nanofluids have been characterized with the sample ofjust after preparation after 30days of preparation and after 60 days.It is studied that the nanofluids with surfactant showed better stability than the nanofluids without surfactant. Found that the nanofluids at 0.7% volume concentration with surfactant showed good stability with negligible visual sedimentation even after 60 days than the nanofluids without surfactant. Therefore the MWCNT/water nanofluids are the potential heat transfer fluids to apply in heat transfer field.Copyright © VBRI Press.
Nitin Kumar; Shivesh Sharma; Seema Nara
Abstract
Commonly used seed-mediated method of gold nanorod synthesis has limitations like formation of by-products (stars, squares, dog-bones, platelets), slow but continuous growth during storage/ageing which adversely affects their homogeneity. Storage in the presence of cetyltrimethylammonium bromide (CTAB) ...
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Commonly used seed-mediated method of gold nanorod synthesis has limitations like formation of by-products (stars, squares, dog-bones, platelets), slow but continuous growth during storage/ageing which adversely affects their homogeneity. Storage in the presence of cetyltrimethylammonium bromide (CTAB) is also essential to prevent their aggregation, which being toxic, needs to be removed before using them for biological applications. We herein, present a simple approach to overcome these limitations through synergistic action of low pH and high temperature. The proposed modifications synthesize highly homogeneous nanorods which are stable upto months even when stored in water. Copyright © 2018 VBRI Press.
