Formulation of high new high energy density materials for use in rocket engines and other important applications
Rocket engines, gas generation mechanisms such as automobile air bags and explosive devices employ high energy density materials (HEDMs) as fuels. Formulating an HEDM having high specific impulse, high density, low production cost, low sensitivity to impact and friction and low toxicity all at the same time is extremely challenging. In this regard, cage compounds with their severely strained molecular structures look promising. Chemical synthesis of such compounds is expensive and tedious.
Electrochemical energy storage materials for powering electric vehicles
Majority of the portable electronic devices used in our day-to-day life, starting from basic cell phone, smart phone, laptop, digital camera, camcorder, tablet, power tools etc. use Li-ion batteries as the power source. Imagine the next generation automobiles also running on such batteries, instead of burning fossil fuels and causing environmental pollution. Yes, there is a definite possibility for the same, leading to saving our environment and having us breathe fresh air, even in the cities.
Plasmonics: The way to efficient photodevices via two-photon lithography
A photodiode is a device capable of converting light energy into electrical signal. The materials used to make these devices critically define the properties and performance of the photo-devices. Thus the materials primarily act as a detrimental factor in limiting the performance of these photo- devices. This bottleneck can be removed partially by using plasmonic structures which can be fabricated easily by two-photon lithography (TPL).
Energy extraction from vortex induced vibration of bi-stable structures
Any elastic structure vibrates in the presence of fluid flow; for instance, we can see leaves in a tree, attached to branches via elastic stems, oscillate furiously on a windy day. These vibrations often occur due to vortices, which are essentially regions of intense fluid rotation. Vortices are periodically shed behind any solid body placed in a fluid flow, and they tend to ‘kick’ the solid as they are shed.
Development of constant temperature microdevice
In several biological applications, it is required to maintain the cells above / below the room temperature implying the need for heating / cooling the microdevice. For instance, in polymerase chain reaction (PCR) a particular DNA sequence is amplified and used in applications such as pathogen detection and hereditary disorder diagnosis. The entire process takes place in 3 steps: denaturation, annealing and extension for which the different stations are required to be maintained at constant temperatures of 95°C, 55°C and 72°C, respectively.
Electricity from waste heat
More than 40% of energy in fossil fuels is lost in the form of ‘heat’ during different conversion processes. This results in not only inefficient usage of natural resources but also leads to environmental and water pollution. One of the techniques that can be used to recover this ‘waste heat’ is via a ‘thermoelectric generator’ which has no moving parts and converts heat directly into electrical power. Our research is focused on developing suitable materials for this purpose with the aim that they have high conversion efficiencies.
Intrinsically conducting polymers for energy storage
Intrinsically conducting polymers such as polyaniline, polythiophene, polypyrrole and polyethylenedioxy thiophene are not only good conductors of electricity, but also possess a property called pseudo-capacitance, which allows them to store electric charge through redox reaction. They therefore possess much higher power density than a battery and phenomenally higher energy density than a capacitor. This dual advantage makes them useful as ‘flywheels’ in energy storage systems. These ‘flywheels’ store surplus energy and provide it when needed.
Molecular nanomagnets: An alternative to silicon-based technology
In order to sustain the progress in the ever growing digital technology, there is need for new tools and resources that more efficiently store and processes digital information along with better economic spending, lower energy consummation and low environmental impact. However, the miniaturisation of electronic devices using current silicon-based technology is about to reach its maximum limit. In order to overcome this difficulties, scientists have now turned their focus to alternative routes.
Wide area measurement applications in power systems
The technology of wide-area measurements systems (WAMS) aims to make available high-quality, system-wide measurements for enhanced monitoring, control and protection applications in a large power system. A key feature of this technology is the precise time synchronisation of the measurements using global position system (GPS) satellites.This feature also allows for the direct measurement of phase angular differences between phasors at distant locations in a power grid. The advent of WAMS has spurred the development of novel methods to determine the health of a power grid.
Hydrogen sorption in metallic materials (Mg, Pd and Pt) for vehicular and sensor applications
Thermal sorption studies on Mg(H2) for vehicular applications
Development of low temperature refrigerators: Production of temperatures below -150°C
Low temperature refrigerators or cryocoolers generate temperatures below -150°C. Depending upon the working cycle or operating principles, there are various types of cryocoolers like Joule-Thompson, Stirling, Gifford-McMahon (GM), Pulse Tube, etc. These refrigerators are used to cool electronics, detectors in thermal imaging, gas cooling, cooling of pharma products,
Thermosyphon system for electronics cooling
With growth and advancement in science and technology, electronics and electrical systems continue to be placed in denser packaging and smaller enclosures. All electronic and electrical devices heat up while working. Due to compact packaging, their temperature rises as sufficient heat cannot be dissipated naturally. For high efficiency and reliable performance of electronic equipment, the rising of temperature above room temperature needs to be controlled. High rise in temperature can be detrimental for the working of the devices.
Enhanced heat transfer using deformable thin plates: Flexible fins
The use of fins to improve heat transfer in engineering systems such as heat-sinks, radiators and IC engines is very common. The present work numerically examines improvements or changes in thermal augmentation, which is possible if a deformable, fin-like structure instead of a rigid one is employed. In biology, employing flexible structures to improve heat transfer is common; for example, elephants thermoregulate their bodies by flapping their large ears, and thermal transport enhancement by oscillating cilia.
Latent heat thermal energy storage for medium temperature solar thermal power plant
Thermal energy storage technologies can reduce the dependency on fossil fuel by making the solar radiation a viable option for electricity generation through solar thermal power plant. This can be done either by integrating with the national power grid or installing in the non-interconnected electric networks, such as small villages and localities.We are working on the design, analysis and development of Phase Change Material (PCM) based thermal energy storage system with small scale capacity (~10-100 kWt).
Gas hydrates: Energy source of the future!
Gas hydrates, which are cages of water molecules entrapping hydrocarbons like methane, ethane etc., are solid snow-like substances found in deep seabed. They are billed as the future energy source as they hold more than two-thirds of world’s organic carbon. The extraction of these hydrocarbons (natural gas) poses several technical challenges, which the researchers worldwide are attempting to solve.First challenge is locating and estimating the potential of these gas hydrate bearing deposits in deep seabed (800 to 1500 m depth).
Permeability of hydrate bearing sediments: A coupled fluid flow mechanism
The rapid growth in population, industrialisation, and infrastructure, has led to over dependence on conventional non - renewable resources (viz., coal, petroleum, and natural gas) for fuel and energy generation, which eventually has resulted in fast depletion of these resources. In this context, naturally occurring methane gas hydrates (solid crystals with methane gas trapped inside water molecules) found in offshore and permafrost regions, can turn out to be one of the potential energy sources for overcoming the energy crunch in the near future.
Thermal characterisation of soil mass
The soil mass is subjected to elevated temperature due to construction of several thermo-active structures like tanks storing heated fluids, buried cables and pipelines, air conditioning ducts, rocket launching pad, disposal system of nuclear and thermal power plant wastes, etc. These result in conveyance of thermal energy through it. At times, the soil mass is subjected to temperature variation due to natural phenomena like freezing and thawing, seasonal and climatic variation, volcanic eruption, etc.
Keep it cool
Many would be aware about the blue-painted houses of the ‘sun city’ Jodhpur, also known as the blue-city for many tourists, where the day temperature is average of about 33.6°C and the record high temperature is 54°C. While on a tour to Jodhpur, we were given to understand by tourist guides that houses are painted white and blue to protect it from the sun’s heat. Travel photos from the Mediterranean and Middle East often show a landscape of homes with white roofs and walls.
Cool roof coatings
High consumption of electricity in running air conditioners / coolers in summer is a usual phenomenon. A rough estimate shows that there is a saving of Rs480 Crores per annum in electricity if the temperature of a roof-top house (size 1000 sq. ft and having a one ton AC, running only for 10 hours) is reduced by 10 o C. This in turn will reduce the carbon foot print and hence global warming.
Growth of strictly monolayer large continuous MoS 2 films on diverse substrates
Despite a tremendous interest on molybdenum disulphide as a thinnest direct band gap semiconductor with a huge potential for application in optoelectronics and plasmonics, single step synthesis of a large area purely monolayer MoS 2 film has not yet been reported. We have adopted a chemical vapour deposition (CVD) route to synthesise a continuous film of strictly monolayer MoS 2 covering an area as large as several mm 2 on a variety of different substrates without using any seeding material or any elaborate pre-treatment of the substrate.