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.

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.

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.

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.

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.

Polycarbocyclic cage compounds

■ Synthesised from readily available starting materials in minimum number of steps

In comparison with conventional propellants/explosives, polycyclic cage compounds exhibit

■ High positive heat of formation (ΔH f ), high density, high angle and torsional strain

■ High specific impulse (I sp ), higher heat capacity, superior burning rate, greater heat release

■ Kinetic stability: stable to light, air and water, no spontaneous decomposition or shock sensitivity

Efficient use of energy is an age-old goal. But its importance has become even more apparent with the increased emphasis on human development and the increased use and thirst for more energy that it engenders.Efficient use of energy is an age-old goal. But its importance has become even more apparent with the increased emphasis on human development and the increased use and thirst for more energy that it engenders.

Our focus is on addressing energy concerns through the use of information and communication technologies:

Pinch Analysis was originally developed as a thermodynamic tool to conserve thermal energy in chemical process industries through a network of heat exchangers.

Due to the simple design, better atomisation and mixing characteristics, the impinging jet configuration has been a preferred injection system for storable liquid propellant rocket engines. The major problem associated with liquid propellant rocket engines using the impinging jet injector configuration is combustion instability. Acoustic oscillations in the combustion chamber affects the process atomisation leading to oscillatory sheet breakup and spray formation. This further causes unsteady heat release favorable for sustaining the combustion instability.

As we know, energy can’t be converted 100% into work. For instance, about more than a third of energy from fuel in internal combustion engine in a car goes into running the vehicle and majority of the fuel gets wasted as a heat. One can harness part of this waste heat (generated in vehicles, electronic circuits, factories as well as in natural heat sources) and turn it into useful energy, which can partly solve some of our energy problems. Thermoelectric materials converts part of the heat into useful electrical current.

Grain-oriented (GO) materials are commonly used in magnetic circuits of power transformers. They provide a high permeable path for the main magnetic flux with minimum iron (or core) losses for magnetisation along their rolling direction (RD). These materials exhibit hysteretic, anisotropic, and dynamic features in their magnetisation process. Numerical simulations have to be carried out to optimise design, to pre-estimate the losses, and to test design performance under transient conditions.

Vacuum circuit breakers (VCBs) are finding increased usage in the medium voltage range (1 - 52 kV) due to their robustness and compactness. As the entire current interruption process takes place inside a closed vacuum enclosure (vacuum bottle), the VCB is maintenance free. Vacuum technology has progressed over the years and VCBs have become increasingly compact. As a result they have developed an edge over SF6 circuit breakers. Presently, VCBs have a comparable market share as that of SF6 breakers in the switchgear sector.

With the rising demand of the energy, India is looking forward to implement advance technology named fracking to explore previously untapped shale gas resources and to rejuvenate old brown fields. In fracking, a large volume of water is forcefully injected in the subsurface to create fractures. These fractures facilitate the movement of hydrocarbons to the producing well. But one of the first and very crucial stages of fracking is the fracture-mechanical characterisation of the target rocks.

The global energy scenario is in dire need of an overhaul. The goal of meeting the future energy demands is only possible by modernising the exploration and exploitation techniques of the hydrocarbon reserves. India has an extensive reserve of coal which can serve its needs for over a century. The use of novel techniques can maximise the energy recovery from coal, and help in bridging the gap between resource and reserve. One such novel technique is underground coal gasification (UCG), which involves the conversion of coal into fuel gas (syngas) within the earth.

Understanding the flow behavior through fractures is critically important in a wide variety of applications. In many situations, the fluid flow can be highly irregular and non-linear in nature. The study of fluid flow through fractures is helpful for systems involving various aspects of reservoir geomechanics. Fluid flow modeling has a major application in oil, gas production, dam foundation, coal mining and waste disposal, subsurface flow and carbon dioxide geosequestration, natural hazards and shale gas extraction.

Two issues that significantly impact the health of the people in the rural areas are the use of solid fuel for cooking and the use of kerosene for lighting. In addition to the adverse health impacts because of the large quantity of emissions (refer figures), the practice of using solid fuel for cooking also involves a huge amount of drudgery in order to collect the fuel wood. This could be as much as walking about 3 - 5 km/day and mostly involves women.

Half-Heusler thermoelectric materials (crystal structure shown in the figure) have attracted extensive research interest over the last two decades owing to their thermal stability, mechanical strength, and moderate efficiency. This project involves a first principles theoretical evaluation of the electrical and thermal transport properties of three bismuth-based most promising thermoelectric alloys. These are brand new compounds, which are recently proposed to be stable [Nature Chem.7, 308 (2015)] and speculated to have interesting properties.

Hybrid perovskites, CH 3 NH 3 PbI 3 (crystal structure shown on the left figure), is one of the most promising novel materials for solar harvesting. Toxicity of lead (Pb), however, has always remained a concern. In this project, we investigated the electronic structure of complete replacement of Pb by alkaline earth elements (Ca, Sr, Ba) and found them to be wide band gap (E g ) semiconductors (band gap ~ 3.7-4 eV), and hence not suitable as absorber material. This opens up a new avenue to explore these materials as transparent conductor (TC).

Ceiling fan is one of the most widely used home appliances. Unfortunately, it is also one of the most inefficient. The conventional single phase induction motor based ceiling fan consumes up to 70-75 W power while the output is only 20-25 W. Therefore, in order to improve the efficiency, a novel switched reluctance motor (SRM) drive is developed to replace the inefficient induction motor. This drive reduces the power consumption of the ceiling fan by 50%. The developed SRM and its power electronic drive shown in the following figures consume only 34 W at the rated ceiling fan speed.

A novel ferrite based semi-modular dual-stack (SMDS) spoke-type BLDC motor is designed and fabricated for a photovoltaic (PV) powered submersible water pump. A new rotor is designed with minimum flux leakage and without the use of a separate non-magnetic hub for the rotor. The proposed flux barrier arrangement uses the bottom bridge of the conventional spoke rotor, and despite being magnetic reduces flux leakage. The use of ferrite magnets makes the motor more economical compared to the rare-earth magnet based motors.