2D carrier confinement in polar semiconductor wedges: A novel route to achieve high mobility devices
A novel route to achieve 2D carrier confinement in a wedge shaped wall structure made of a polar semiconductor has been demonstrated. Our theory reveals that the wedge shape leads to the development of charges of equal polarity on the two inclined facades of the wall. Polarisation induced negative (positive) charges on the facades can push the electrons (holes) inward for a n-type (p-type) material which results in the formation of a 2D electron (hole) gas at the central plane and ionised donors (acceptors) at the outer edges of the wall.
Gunshot localisation using acoustics
Modern gun-battles are rarely waged on open ground where enemies face each other, and the origin of unfriendly and friendly fire are easy to locate. Instead, most combats are now staged in obstacle-dense situations like cities, forests and mountain valleys, where the location of a shooter may be difficult to pinpoint aurally due to reverberations. More importantly, our security forces may not even be present within audible range of all gunshots at all times, due to the highly mobile nature of modern combat.
Impact of manufacturing defects and operation induced defects on wind turbine blade quality and reliability
Composites have been extensively used in the manufacturing of wind turbine blades over the past two decades. Significant expertise and field experience has been accumulated in the design, manufacturing and repair / maintenance of these wind turbine blades. However, with the increasing blade length, the design imperatives have pushed the materials used for the blade construction from conventional E-glass to carbon fiber based polymer composites. This shift also leads to design shift from stiffness limited design to strength limited design.
Development of particle image velocimetry instrument for fluid velocity measurement
Particle image velocimetry (PIV) technique is used for measurement of fluid velocity. It involves seeding micron-size particles in a flow, illuminating the particles with a laser pulse, capturing the position of the particles using a camera, and finally interrogating two such time elapsed images to obtain the displacement (and velocity) of the particle (or flow). The technique provides information at numerous points simultaneously and is non-intrusive; these advantages make PIV score substantially higher than conventional techniques (such as Pitot tube).
Flameless combustion: An emissions reduction technique in gas turbine combustors
In current scenario, environmental pollution has become a greater challenge for the whole mankind. Main source of the pollutant includes industrial applications, air and land based traffic. These emissions are mainly CO, NO x and UHC (unburned hydro carbon) causing many harmful effects like acid rain, smog and haze resulting in global warming. It is expected that emissions norms will become stricter in near future. It is reported that by 2025, NO x , CO and UHC should be reduced by 80%.
Development of small scale stand alone thermoelectric power generation systems using microcombustors
Combustion driven power sources offer astounding advantages over conventional chemical batteries, such as higher energy densities, lower weight, short recharging time, limitless number of rechargeable cycles and environment friendly operation. These devices have wide applications in micro satellite thrusters, MEMS, chemical sensing,and micro air vehicles (MAV).
Experimental facility for measurement of laminar burning velocities of multicomponent gaseous fuel mixtures at high temperatures
The cleaner and higher efficiency burning of syngas mixtures in integrated gasification combined cycle (IGCC) have made syngas the most promising alternative to conventional fossil fuels for power generation. The burning velocity is an intrinsic property of a combustible mixture that characterises the overall reaction rate of the flame. We determined the laminar burning velocities of multi-component mixtures experimentally at elevated temperatures. The combustion characteristics of practical syngas mixtures is vital for efficient use of lean premixed mode of syngas-air mixtures in IGCC.
Flame dynamics in micro/meso scale channels
Identification of small-scale combustion based devices as high energy density source and development of modern microfabrication techniques has led to many opportunities in the area of development of micro-power generation devices. These combustion based micro power devices are expected to feed the portable micromechanical, communication, sensing biomedical systems, UAVs, micro-thrusters and various micro-scale industrial applications.
High fidelity burning velocity data for liquid biofuels for cleaner combustion
The interest of the automotive and aviation community in biofuels has surged in the past decade primarily due to a shift in global awareness towards cutting greenhouse gas emissions. This has translated into stringent policies for fuel usage and emission norms. In this context, the research community has shifted its focus towards biofuels as a part of the larger renewable plan for the planet.
TMT central diaphragm manufacturing process technology development
TMT (Thirty Meter Telescope) is one of the world’s largest ground based telescope project. The telescope’s primary mirror is 30 meters in diameter and is comprised of hundreds of hexagonal mirror segments. Each mirror segment is mounted on a critical support component known as the central diaphragm.