K Nantha Gopal

Bio: K Nantha Gopal is an academic researcher from VIT University. The author has contributed to research in topics: Physics & Laser. The author has an hindex of 4, co-authored 11 publications receiving 285 citations.

Nonlinear mixing-based terahertz emission in inclined rippled density plasmas

Abstract: We propose to investigate the THz field generation using nonlinear mixing mechanism of laser beat wave with inclined rippled density plasmas. Two laser pulses with frequencies (ω 1, ω 2) and wave vectors (k 1, k 2) co-propagate and resultant laser beat wave forms at beat frequency (ω 1–ω 2). Laser beat wave imparts a nonlinear force on the ambient electrons and pushes them outward with nonlinear velocity v NL. Coupling of induced density perturbation and nonlinear velocity v NL generates nonlinear currents at laser beat frequency that further generates electromagnetic field E (ω 1–ω 2) in terahertz (THz) range. In the present scheme, density ripples are introduced at an angle with respect to laser propagation and flat Gaussian index (f) is introduced in laser field profile that transform curved top of Gaussian field envelope into flat top field envelope. The combined effect of flat laser pulses with inclined density ripples in plasmas shows 10-fold enhancement in THz field amplitude when flat-Gaussian index (f) varies from 1 to 4. Also, the THz field intensifies when density ripples inclination increases upto a certain angle and then decreases.

A review on the properties, performance and emission aspects of the third generation biodiesels

Abstract: In the effect of robust industrialization and rapid augmentation of a number of fleets, there has been a huge rise in the fossil fuel consumption. Tremendous increase in global warming threatens the ecological balance of the earth. Based on the recent sorts of hardship about the fuel, researchers are profoundly pondered over the field of renewability, environmentally friendly and economically doable. In recent decades biodiesel fuel becomes the center of attraction among researchers since it is renewable, bio degradable, non-noxious, eco-friendly and sustainable. This review paper highlights and reviews the properties of prosperous variety of the biodiesel fuels derived from non-edible feedstocks which are termed as third generation biodiesel and its effects on the performance and emissions of the diesel engines. It was observed that the physicochemical properties of the biodiesel differ based on the types of feedstocks and also have a considerable effect on the potential performance of engine and dynamic characteristics of emission level. Also, the usage of biodiesel commonly leads to a reduction in noxious pollutants like carbon monoxide, unburnt hydrocarbon and particulate matter with an obvious increase in fuel consumption and NOx emission. This review provides a prospective strategy for the researchers for enhancing the engine performance and emission characteristics by using the third generation biofuels and its blends with the productive marvelous outcomes.

A comprehensive review on performance, combustion and emission characteristics of biodiesel fuelled diesel engines

Abstract: Direct injection diesel engines are more popular in the automotive sector than spark ignition (SI) engines due to its fuel lean operation However, the demand of fossil fuel is rising day by day and hence the major fuel source of diesel engine, the petroleum based fuel, is depleting rapidly Many countries depend mainly on imported fossil fuels due to lack of fuel reserves and it has great impact on the economy In addition to this, the major concerns of diesel engine are its oxides of nitrogen and smoke emissions Therefore, for the past several decades extensive efforts are being made to search for alternate fuels to overcome the dependence on fossil fuel and environment pollution In this regard, several alternate fuels namely hydrogen, oxygenated fuels like alcohol fuels, dimethyl ether and biodiesel fuels etc, have been extensively analysed Recent studies show that biodiesel is one of the most promising alternate fuels for diesel engines because of its biodegradable, oxygenated, sulphur free and renewable characteristics Hence, it is getting the attention of researchers all over the world The blends of biodiesel with fossil diesel have many benefits like reduction in emissions, lower engine wear, lesser engine oil consumption and comparable thermal efficiency vis-a-vis diesel fuel Exhaustive experimental works have been carried out to analyse the suitability of biodiesel fuel as alternate fuel and to explore their advantages in diesel engines Hence, this paper is attempted to present a comprehensive review on the performance, combustion and emission characteristics of some important biodiesel fuels on diesel engines This comprehensive review on the published literature will be helpful to the researchers to understand the state-of-the-art technology of the biodiesel fuelled compression ignition engine

Biodiesel as alternative fuel for marine diesel engine applications: a review.

Abstract: Transportation and shipping activities are major contributor to air pollution at sea where most of it occurs as a result of exhaust emissions from ships. Stringent emission limitations enforced by the International Maritime Organization have hastened the need to find a new alternative fuel for marine diesel engines. Thus, biodiesel fuel was chosen as one of the environmentally friendly alternative energy that can reduce ship toxic gas emissions and at the same time reduces dependence on petroleum-based fuels. Therefore, the purpose of this paper is to provide a comprehensive review of biodiesel as an alternative fuel for marine diesel engine applications. This review covers the biodiesel fuel background, engine performance, history, recent progress, engine warranty, issues, challenges, and possible solutions on using biodiesel for marine applications. A significant number of literatures from indexed journals were cited accordingly. The results of previous studies had shown that the use of biodiesel would mostly increase the amount of brake specific fuel consumption and nitrogen oxide gas while conversely reducing other toxic gas emissions. Although a number of issues and challenges arise, most marine engine manufacturers give conditional warranty against the use of biodiesel in the engines. The study concluded that biodiesel and its blends have a bright future in the marine sector, provided some of the highlighted issues can be solved.