P. Chandramohan

Bio: P. Chandramohan is an academic researcher from Sri Ramakrishna Engineering College. The author has contributed to research in topics: Corrosion & Ultimate tensile strength. The author has an hindex of 8, co-authored 30 publications receiving 592 citations. Previous affiliations of P. Chandramohan include University of Johannesburg & Sri Krishna College of Engineering & Technology.

Renewable energy source water pumping systems—A literature review

Abstract: The research developments with renewable energy source water pumping systems (RESWPSs) are reviewed in this paper. The reported investigations are categorized into five major groups as follows: (i) solar photovoltaic water pumping systems (SPWPSs), (ii) solar thermal water pumping systems (STWPSs), (iii) wind energy water pumping systems (WEWPSs), (iv) biomass water pumping systems (BWPSs) and (v) hybrid renewable energy water pumping systems (HREWPSs). More than a hundred published articles related to RESWPSs are briefly reviewed. Additionally, the limitations with RESWPSs and further research needs are described. This paper concludes that renewable energy sources (RESs) play a vital role in reducing the consumption of conventional energy sources and its environmental impacts for water pumping applications.

Performance investigation on fin type solar still with paraffin wax as energy storage media

Abstract: It is indispensable to enhance the performance of a conventional solar still in order to increase its productivity. It has been effectively done by adding fins and thermal energy storage media to it. In the present work, the performance of a conventional single slope solar still is compared with an identical solar still with square pipes as fins attached to its basin liner. A thin layer of paraffin wax was stored beneath the basin liner as well as in the hollow space present in the square pipe fins as energy storage media. Experiments have been conducted on the conventional still for three different water depths, i.e. for 2, 3 and 4 cms. The masses for the corresponding water depths are 10 kg, 15 kg and 20 kg, respectively. The same water masses were maintained in the modified still, and experiments were conducted for the following cases: with mere fins and with fins cum energy storage media. The percentage increase in the efficiencies of the modified still with mere fins and with fins cum energy storage are observed as 64% and 95%, respectively.

Laser additive manufactured Ti–6Al–4V alloy: tribology and corrosion studies

Abstract: The effect of heat treatments (HT) on wear and corrosion of direct metal laser-sintered Ti–6Al–4V specimens have been studied. Rectangular parts were built in vertical (VB) and horizontal (HB) directions and heat treated above β transus and below β transus with different cooling rate. Rotary wear tests have been carried out under varying loads of 5 N, 15 N and 25 N at 25 m/s. Corrosion behaviour were analysed in 1 M H2SO4,1 M HCl and 3.5% NaCl solutions. Wear volume loss of both HB and VB are less in specimens subjected to HT 2 than in HT1 which is attributed to more grain refinement. Presence of compact oxide debris on the surface of HT 2-VB specimen could have contributed to the low wear volume. A sharp positive difference could be observed in OCP immersed in 1 M H2SO4solution from −0.6 V (as-sintered) to 0.069 V (HT 1-HB) and 0.089 V (HT 2-HB). Icorr value in 1 M H2SO4 improved after both the heat treatments from 17.450 μA/cm2 to 1.470 and 0.152 11 μA/cm2, respectively. Generally, heat-treated specimens (both horizontal and vertical) show better corrosion resistance than the as-sintered specimens in all the three media.

Review on life cycle assessment of energy payback and greenhouse gas emission of solar photovoltaic systems

Abstract: This paper aims to examine the sustainability and environmental performance of PV-based electricity generation systems by conducting a thorough review of the life cycle assessment (LCA) studies of five common photovoltaic (PV) systems, i.e., mono-crystalline (mono-Si), multi-crystalline (multi-Si), amorphous silicon (a-Si), CdTe thin film (CdTe) and CIS thin film (CIS), and some advanced PV systems. The results show that, among the five common PV systems, the CdTe PV system presents the best environmental performance in terms of energy payback time (EPBT) and greenhouse gases (GHG) emission rate due to its low life-cycle energy requirement and relatively high conversion efficiency. Meanwhile, the mono-Si PV system demonstrates the worst because of its high energy intensity during the solar cells’ production process. The EPBT and GHG emission rate of thin film PV systems are within the range of 0.75–3.5 years and 10.5–50 g CO 2 -eq./kW h, respectively. In general, the EPBT of mono-Si PV systems range from 1.7 to 2.7 years with GHG emission rate from 29 to 45 g CO 2 -eq./kW h, which is an order of magnitude smaller than that of fossil-based electricity. This paper also reviews the EPBT and GHG emission rates of some advanced PV systems, such as high-concentration, heterojunction and dye-sensitized technologies. The EBPT of high-concentration PV system is lower, ranging from 0.7 to 2.0 years, but the CO 2 emission rate of dye-sensitized PV system is higher than the ones of other PV systems at the moment. The LCA results show that PV technologies are already proved to be very sustainable and environmental-friendly in the state of the art. With the emerging of new manufacturing technologies, the environmental performance of PV technologies is expected to be further improved in the near future. In addition, considering the existing limitations in the previous LCA studies, a few suggestions are recommended.

Review of solar photovoltaic water pumping system technology for irrigation and community drinking water supplies

Abstract: The deficit in electricity and high diesel costs affects the pumping requirements of community water supplies and irrigation; so using solar energy for water pumping is a promising alternative to conventional electricity and diesel based pumping systems. Solar water pumping is based on photovoltaic (PV) technology that converts solar energy into electrical energy to run a DC or AC motor based water pump. The main objective of the study is to present a comprehensive literature review of solar pumping technology, evaluate the economic viability, identify research gaps and impediments in the widespread propagation of solar water pumping systems and technology. The study focuses on update on solar water pumping technology, performance analysis, optimum sizing, degradation of PV generator supplying power to pump, economic and environmental aspects and advances in PV materials and efficiency improvements. An update on the current state of research and utilization of solar water pumping technology is presented. Factors affecting performance of PV water pumping system, degradation of PV modules and efficiency improving techniques of PV water pumping systems are identified. Solar water pumping is found to be economically viable in comparison to electricity or diesel based systems for irrigation and water supplies in rural, urban and remote regions. The investment payback for some PV water pumping systems is found to be 4–6 years. The recent Indian incentives for PV pumping and policy initiatives for the promotion of solar water pumping in developing countries are also discussed. Potential follow-up research areas are also identified.

Carbon steel corrosion: a review of key surface properties and characterization methods

Abstract: Corrosion is a subject of interest to interdisciplinary research communities, combining fields of materials science, chemistry, physics, metallurgy and chemical engineering. In order to understand mechanisms of corrosion and the function of corrosion inhibitors, the reactions at the interfaces between the corrosive electrolyte and a steel surface, particularly at the initial stages of the corrosion process, need to be described. Naturally, these reactions are strongly affected by the nature and properties of the steel surfaces. It is however seen that the majority of recent corrosion and corrosion-inhibition investigations are limited to electrochemical testing, with ex situ analysis of the treated steels (post-exposure analysis). The characterization of materials and their surface properties, such as texture and morphology, are not being considered in most studies. Similarly, in situ investigations of the initial stages of the corrosion reactions using advanced surface characterization techniques are scarce. In this review, attention is brought to the importance of surface features of carbon steels, such as texture and surface energy, along with defects dislocation related to mechanical processing of carbon steels. This work is extended to a critical review of surface analytical techniques used for characterization of carbon steels in corrosive media with particular focus on examining steel surfaces treated with corrosion inhibitors. Further, emerging surface analysis techniques and their applicability to analyse carbon steels in corrosive media are discussed. The importance of surface properties is commonly addressed by surface scientists as well as researchers in other chemistry fields such as nanotechnology, fuel cells, and catalysis. This article is expected to appeal to a broad scientific community, including but not limited to corrosion scientists, material chemists, analytical chemists, metal physicists, corrosion and materials engineers.

Titanium metal matrix composites: An overview

Abstract: Titanium matrix composites (TMCs) offer high specific strength and stiffness compared with steel and nickel-base materials. High-temperature TMCs can offer up to 50% weight reduction relative to monolithic superalloys while maintaining equivalent strength and stiffness in jet engine propulsion systems. Regardless of the reinforcements are continuous fibres or discontinuous particulates, the unique properties of TMCs have thrust them to the forefront of extensive research and development programmes around the world. Even though TMCs are one of the most studied and sought-after material systems, useful information about their properties, fabrication methods and design is scattered in the literature. This review covers important research work that has led to the advances in TMCs material systems. It also provides comprehensive details about common reinforcements, manufacturing processes, and reviews static and dynamic properties of some common TMCs. The review also presents common industrial applications of TMCs and highlights the promising outlook of TMCs.