scispace - formally typeset
Search or ask a question
Author

Raja Ram Yadav

Bio: Raja Ram Yadav is an academic researcher from Allahabad University. The author has contributed to research in topics: Nanofluid & Attenuation. The author has an hindex of 19, co-authored 45 publications receiving 873 citations. Previous affiliations of Raja Ram Yadav include Veer Bahadur Singh Purvanchal University.

Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, a nanorod of zinc ferrite was synthesized and fabricated by employing sol-gel spin coating process and the synthesized material was characterized using X-ray diffraction, scanning electron microscopy, acoustic particle sizer, atomic force microscopy and infrared spectroscopic techniques.

89 citations

Journal ArticleDOI
TL;DR: The nanorods with unusually high optical bandgap for a VO2 material are effective in enhancing the thermal performance of ethylene glycol nanofluids over a wide temperature range as is indicated by the temperature dependent thermal conductivity measurements.
Abstract: VO2 (B) nanorods with average width ranging between 50-100 nm are synthesized via a hydrothermal method and the post hydrothermal treatment drying temperature is found to be influential in their overall phase and growth morphology evolution. The nanorods with unusually high optical bandgap for a VO2 material are effective in enhancing the thermal performance of ethylene glycol nanofluids over a wide temperature range as is indicated by the temperature dependent thermal conductivity measurements. Humidity and LPG sensors fabricated using the VO2 (B) nanorods bear testament to their efficient sensing performance, which can be partially attributed to the mesoporous nature of the nanorods.

69 citations

Journal ArticleDOI
TL;DR: In this paper, a series of fascinatingly shaped nanostructures, e.g. seeds, ellipsoidal, rods and leaves, were obtained and applied as nanofluids (water medium) showed their ability to enhance the thermal conductivity of water to a noticeable degree (above 40%) at high temperatures, even at very small concentrations, bespeaking their applicability in cooling fluids.
Abstract: Different nanoscale objects of CuO have been synthesized by a simple chemical route where the Cu(OH)2 nanostructures were first synthesized by the alkaline hydrolysis of Cu(NO3)2·3H2O using NaOH as a base and the synthesized precipitate was subsequently annealed at a temperature of 130 °C. The alkaline content (pH) of the solutions during the hydrolysis process was varied to tailor the morphologies and dimensions of the nanostructures, consequently a series of fascinatingly shaped nanostructures, e.g. seeds, ellipsoidal, rods and leaves were obtained. Topographical characteristics along with the mechanism behind the structural variation have been rationalized by XRD, FTIR, SEM and HRTEM investigations. Optical performance of these samples provided simultaneous emission in the visible bands of blue, green, yellow and red, which were correlated to the size, shape and structural defects of these nano-scaled objects. The toxicity of these nanostructured materials were also put into perspective and it was found that the leaf shaped particles were the most toxic among the various shapes of nano-CuO. Finally the synthesized particles, when applied as nanofluids (water medium) showed their ability to enhance the thermal conductivity of water to a noticeable degree (above 40%) at high temperatures, even at very small concentrations, bespeaking their applicability in cooling fluids.

64 citations

Journal ArticleDOI
TL;DR: In this article, the second order elastic constants of hexagonal structured (wurtzite) third group nitrides (GaN, AlN and InN) were calculated using the Lennard-Jones potential for the determination of ultrasonic attenuation.

59 citations

Journal ArticleDOI
TL;DR: In this paper, the antimicrobial activity of trimetallic Au/Pt/Ag nanoparticle based nanofluids were studied and compared with that of monometallic Au and bimetallic Au-Pt.

56 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: A comprehensive review of recent synthetic methods along with associated synthesis mechanisms, characterization, fundamental properties, and promising applications of Cupric oxide (CuO) nanostructures is presented in this article.

1,030 citations

Journal Article
TL;DR: The International Nanofluid Property Benchmark Exercise (INPBE) as discussed by the authors was held in 1998, where the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or "nanofluids" was measured by over 30 organizations worldwide, using a variety of experimental approaches, including the transient hot wire method, steady state methods, and optical methods.
Abstract: This article reports on the International Nanofluid Property Benchmark Exercise, or INPBE, in which the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or “nanofluids,” was measured by over 30 organizations worldwide, using a variety of experimental approaches, including the transient hot wire method, steady-state methods, and optical methods. The nanofluids tested in the exercise were comprised of aqueous and nonaqueous basefluids, metal and metal oxide particles, near-spherical and elongated particles, at low and high particle concentrations. The data analysis reveals that the data from most organizations lie within a relatively narrow band (±10% or less) about the sample average with only few outliers. The thermal conductivity of the nanofluids was found to increase with particle concentration and aspect ratio, as expected from classical theory. There are (small) systematic differences in the absolute values of the nanofluid thermal conductivity among the various experimental approaches; however, such differences tend to disappear when the data are normalized to the measured thermal conductivity of the basefluid. The effective medium theory developed for dispersed particles by Maxwell in 1881 and recently generalized by Nan et al. [J. Appl. Phys. 81, 6692 (1997)], was found to be in good agreement with the experimental data, suggesting that no anomalous enhancement of thermal conductivity was achieved in the nanofluids tested in this exercise.

881 citations

Journal ArticleDOI
TL;DR: Nanofluids have seen enormous growth in popularity since they were proposed by Choi in 1995 as mentioned in this paper, and there were nearly 700 research articles where the term nanofluid was used in the title, showing rapid growth from 2006 (175) and 2001 (10).
Abstract: Nanofluids—a simple product of the emerging world of nanotechnology—are suspensions of nanoparticles (nominally 1–100 nm in size) in conventional base fluids such as water, oils, or glycols. Nanofluids have seen enormous growth in popularity since they were proposed by Choi in 1995. In the year 2011 alone, there were nearly 700 research articles where the term nanofluid was used in the title, showing rapid growth from 2006 (175) and 2001 (10). The first decade of nanofluid research was primarily focused on measuring and modeling fundamental thermophysical properties of nanofluids (thermal conductivity, density, viscosity, heat transfer coefficient). Recent research, however, explores the performance of nanofluids in a wide variety of other applications. Analyzing the available body of research to date, this article presents recent trends and future possibilities for nanofluids research and suggests which applications will see the most significant improvement from employing nanofluids.

679 citations