Declassification of Faceted Values in JavaScript

This research addresses the issues with protecting sensitive information at the language level using information flow control mechanisms (IFC). Most of the IFC mechanisms face the challenge of releasing sensitive information in a restricted or limited manner. This research uses faceted values, an IFC mechanism that has shown promising flexibility for downgrading the confidential information in a secure manner, also called declassification. In this project, we introduce the concept of first-class labels to simplify the declassification of faceted values. To validate the utility of our approach we show how the combination of faceted values and first-class labels can build various declassification mechanisms

SOLAR ENERGY HARVESTING FOR PHOTOVOLTAIC CELLS AND PHOTOCATALYSIS

In recent years, alternative energy resources have gathered tremendous attention due to an increase in energy demand and overcome the global effects of burning fossil fuels. Solar energy is an abundant and clean resource of energy and is one of the most promising alternatives to fossil fuels. This thesis investigates the various approaches to harvesting the solar energy and transforming it into electrical and chemical energy. The primary focus of this thesis is employing plasmonic metal nanoparticles as light harvesting elements in photovoltaic cells and photocatalytic materials. Triangular metal nanoparticles (Au, Ag) exhibit strong plasmonic effects due to the presence of sharp features, and their optical properties are tunable based on their size. By integrating Ag@SiO2 nanotriangles in dye-sensitized solar cells (DSSCs), ca. 30% enhancement in the power conversion efficiency (PCE) was achieved. However, the sharp features of Ag nanotriangles are not stable, and the Ag nanotriangles are oxidized at elevated temperatures. The changes in the morphology of these Ag@SiO2 nanoparticles at different annealing temperatures and in different environments (dry air and N2) was studied by X-ray absorption spectroscopy (XAS). Upon annealing in air, the silver nanotriangles decomposed to small (~2 nm) Ag particles, whereas in a N2 atmosphere, they formed truncated triangles. To overcome this stability issue, Ag@SiO2 nanotriangles were replaced by Au@SiO2 nanotriangles. By integrating these nanomaterials in DSSCs, panchromatic light harvesting in the device was achieved. Plasmonic light harvesting was also explored as a route to promote Pd catalysis using AuPd nanotriangles. Upon light illumination, the energy from excited plasmons in Au is transferred to Pd, and this resulted in an enhancement in the rates of the reactions. Recently, another new light harvesting material based on organic-inorganic hybrid perovskites (CH3NH3PbX3; X= Cl, I, Br) has been explored in solar cells. In perovskite solar cells, to determine the optimum conditions for efficient light harvesting and charge collection, the perovskite layer thickness and relative humidity (RH) in the atmosphere were investigated. Results showed ~ 300 nm thick perovskite layers and 40% atmospheric RH are the best conditions for achieving efficient devices

Humidity resistant fabrication of CH3NH3PbI3 perovskite solar cells and modules

A humidity resistant and versatile fabrication method for the production of very high quality, organic-inorganic perovskite films, solar cells and solar modules is presented. By using ethyl acetate as an anti-solvent during deposition, perovskite solar cells with power conversion efficiencies (PCEs) up to 15% were fabricated in a 75% relative humidity (RH) environment. Ethyl acetate acts as a moisture absorber during spin-coating, protecting sensitive perovskite intermediate phases from airborne water during film formation and annealing. We have demonstrated the manufacture of 50 mm x 50 mm series interconnected modules with PCEs in excess of 10% for 13.5 cm2 devices processed in air at 75%RH and 11.8% at 50%RH. To the best of our knowledge, these results represent the highest efficiency for perovskite solar modules processed under high humidity ambient conditions. This new deposition protocol allows for low-cost, efficient and consistent device fabrication in humid climates and uncontrolled laboratories

Design and analysis of tilt rotor unmanned aerial vehicle (UAV) for optimal flight endurance and payload lift capacity

Unmanned Aerial Vehicles (UAVs) are used on a wide range of missions depending on the situation and requirement for that task that has to be completed. UAVs are nothing but aircraft which fly without the physical presence of the pilot. They can be controlled from the ground station and are capable to perform autonomous flights. Some key factors which affect the flights of the UAV are the take-off distance, total time of flight, payload lifting capacity thrust to weight ratio, aerodynamic and structural force effects, and others. Helicopters are used in the areas where the take-off space is less and places where there is a need to hover around a location. Mostly in the case of military applications during surveillance and rescue operations. Airplanes are used to cover large distances for commercial and cargo transportation. Combining the concept of vertical take-off from helicopters and the cruising ability of airplanes, tilt rotors are one of the best ways to satisfy both conditions. There is no doubt that it has one of the most complex stability parameters as it undergoes the transition state in between helicopter mode and airplane mode. Hence the present work concentrates on the design and analysis of tilt-rotor UAV which helps in changing the values of parameters for optimal flight endurance and try to increase the payload lifting capacity of tilt rotor. Keywords – UAV, Design, Analysis, and Tiltrotor

Acoustic Localization by Interaural Level Difference

Interaural level difference (ILD) is an important cue for acoustic localization. Although its behavior has been studied extensively in natural systems, it remains an untapped resource for computer-based systems. We investigate the possibility of using ILD for acoustic localization, deriving constraints on the location of a sound source given the relative energy level of the signals received by two microphones. We then present an algorithm for computing the sound source location by combining likelihood functions, one for each microphone pair. Experimental results show that accurate acoustic localization can be achieved using ILD alone. 1