7-Jun-2021: New eco-friendly process enhances fatigue life of aluminium alloy used in aerospace components
Indian Scientists have developed an environmental-friendly process, which can provide excellent corrosion resistance to the high-strength aluminium (Al) alloys extensively used in aerospace, textile, and automotive applications. It involves an electrochemical method for the production of an oxide film on the metallic substrate.
High-strength aluminium (Al) alloys are extensively used in aerospace, textile, and automotive applications owing to their low density and high specific strength. Aerospace components made out of Al alloys include landing gear, wing spar, which is the main structural part of the wing, fuselage (main body of an aircraft), aircraft skins or outer surface and pressure cabins. These parts often need resistance against wear, corrosion damages, and enhanced fatigue life. The widely used technique for Al alloys to improve corrosion resistance called hard anodizing (HA) process is an electrolyte-based coating deposition. It involves sulphuric/oxalic based electrolytes, which emits not only toxic fumes but are also hazardous to handle during processing.
In order to cater to the growing demand for cleaner industrial processes, an environmental-friendly process called micro-arc oxidation (MAO) has been developed at International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), an autonomous R&D Centre of the Department of Science and Technology, Govt. of India. The process which involves an alkaline electrolyte is capable of providing better wear and corrosion resistance compared to the HA process.
MAO is a high-voltage driven anodic-oxidation process, which through an electrochemical method, produces an oxide film on a metallic substrates. ARCI team has further designed and developed a duplex treatment of shot peening (process used to modify the mechanical properties of metals and alloys) followed by MAO coating deposition. Systematic investigations conducted at ARCI have shown that the duplex treatment has led to the remarkable enhancement in aerospace Al alloys' fatigue life while retaining the outstanding corrosion and wear resistance of MAO coating. The efficacy of duplex treatment has been validated for different Al alloys and extended to impart superior corrosion fatigue life. This work has been recently published in the ‘International Journal of Fatigue’.
The MAO process developed at ARCI has been patented in India and abroad. The team at ARCI has mastered the design and development of MAO systems of a lab (20 kVA), bench (75 kVA), and industrial (up to 500 kVA) scales to enable translating the technology from the R&D level to commercial production. As a logical extension, the custom-built technology systems were transferred to various industries and academic institutes in India. To cater to the aerospace segment, extensive research has been carried out at ARCI, and the high-cycle fatigue life of aerospace Al alloys under plain and simultaneous corrosion environments could be significantly improved.
The process with necessary modifications can be used for wear, corrosion, thermal, and fatigue and corrosion-fatigue life enhancement of a variety of components made out of Al, Mg, Ti, Zr, and their alloys.
20-May-2021: Theory by Indian Scientists to shed light on mystery behind complex phenomena in Plasma-- the fourth state of matter
Indian Scientists have recently developed a theory that helps understand the complicated nature of Sun-Earth interaction's happening in the magnetosphere-- an area of space around Earth that is controlled by the Earth’s magnetic field. This new theory has opened up a plethora of opportunities to unlock the mysteries of the ion-hole structures (a localized plasma region where the ion density is lower than the surrounding plasma). They are now working towards a detailed study of the ion hole structures observed in various space and astrophysical environments using the developed theory.
A group consisting of Mr. Harikrishnan, Prof. Amar Kakad, and Prof. Bharati Kakad from the Indian Institute of Geomagnetism (IIG), an autonomous institute under the Department of Science & Technology, Government of India developed a theory that solves every bit of uncertainty regarding the conflict between the observations from Magnetospheric Multiscale (MMS) Mission ---a NASA robotic space mission to study the Earth's magnetosphere and theoretical predictions. They were also supported by Prof. Peter Yoon from the University of Maryland, USA. They have completely ruled out the necessity of the upper limit in the temperature ratio between ions and electrons for the generation of a special kind of wave called Bernstein Green Kruskal (BGK) waves, named after the scientists who predicted this wave. They revealed that the electrons that are not part of ion hole dynamics also play a vital role. This work has also been published in the journal ‘Monthly Notices of the Royal Astronomical Society’.
On November 2, 2017, NASA's latest expedition to unlock Sun-Earth interaction's complicated nature, the MMS spacecraft, observed negative monopolar potential (electric field potentials which can be visualized in the form of single-humped pulse-type structures). The scientific community suddenly recognized its importance, and publications were presented. However, none of the available theories could explain the characteristics of these structures due to the exotic background conditions. The new theory developed by the IIG team provides a better understanding of their characteristics and sheds light on the generation of these structures leading to the unraveling of nature's greatest mystery that causes phenomena ---plasma transport and heating of plasma -- the fourth state of matter after solid, liquid, and gas, which is the most natural and widely observed state of matter in the entire universe.
12-Sep-2020: Krishna-Godavari (KG) basin, an excellent source of fuel methane
As the world runs out of fossil fuels and looks out for alternate sources of clean energy, there is good news from the Krishna-Godavari (KG) basin. The methane hydrate deposit in this basin is a rich source that will ensure adequate supplies of methane, a natural gas.
Methane is a clean and economical fuel. It is estimated that one cubic meter of methane hydrate contains 160-180 cubic meters of methane. Even the lowest estimate of methane present in the methane hydrates in KG Basin is twice that of all fossil fuel reserves available worldwide.
In a recent study conducted by researchers at the Agharkar Research Institute (ARI), an autonomous institute of the Department of Science and Technology, Govt. of India have found that the methane hydrate deposits are located in the Krishna-Godavari (KG) basin are of biogenic origin. The study was conducted as a part of the DST-SERB young scientist project titled ‘Elucidating the community structure of methanogenic archaea in methane hydrate’. Methane hydrate is formed when hydrogen-bonded water and methane gas come into contact at high pressures and low temperatures in oceans.
According to the present study accepted for publishing in the journal ‘Marine genomics’, the ARI team has further identified the methanogens that produced the biogenic methane trapped as methane hydrate, which can be a significant source of energy.
“The massive methane hydrate deposits of biogenic origin in the Krishna-Godavari (KG) basin and near the coast of Andaman and Mahanadi make it necessary to study the associated methanogenic community,” said Dr. Vikram B Lanjekar, the Principal Investigator of the study.
According to the ARI team, until recently, there have been only a few investigations of the methanogenic communities associated with methane hydrate-bearing sediments. This study has shown that methanogens under these elevated pressure and temperature conditions are well adapted to these conditions and are different in methane-producing activities. Understanding of these methane-producing methanogenic communities under such an extreme and pristine environment was very important. This study using molecular and culturing techniques revealed maximum methanogenic diversity in the KG basin, which is one of the prominent reasons to confirm it to be the extreme source of biogenic methane in comparison to the Andaman and Mahanadi basins.
The kinetics study based on their model also predicted the rate of biogenic methane generation in KG Basin hydrates to be 0.031 millimoles methane/gTOC/Day, resulting in total deposits of methane around 0.56 to 7.68trillion cubic feet (TCF). The sediment samples associated with methane hydrate deposits from Krishna Godavari, Andaman, and Mahanadi basin were provided by National Gas Hydrate Core Repository, GHRTC, ONGC, Panvel, Maharashtra for this study.
The ARI team has documented a predominance of genus Methanosarcina in KG basin, followed by a few other genera Methanoculleus, Methanobacterium. Genus Methanosarcina was found to be more diverse among the obtained genera with four different species M. siciliae, M. barkeri, M. flavescens, and M. mazeias per their findings.
“Cultivation, isolation, and characterization of putative novel Methanoculleus sp. nov. and Methanosarcinaspnov. from methane hydrate sediments of Krishna Godavari basin, India are reported for first time,” said Dr. Vikram B Lanjekar, Principle Investigator of the study.