Role of substrate quality on the performance of semipolar (11 2 - 2) InGaN light-emitting diodes

We compare the optical properties and device performance of unpackaged InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) emitting at ∼430 nm grown simultaneously on a high-cost small-size bulk semipolar (11 2 - 2) GaN substrate (Bulk-GaN) and a low-cost large-size (11 2 - 2) GaN template created on patterned (10 1 - 2) r-plane sapphire substrate (PSS-GaN). The Bulk-GaN substrate has the threading dislocation density (TDD) of ∼ and basal-plane stacking fault (BSF) density of 0 cm-1, while the PSS-GaN substrate has the TDD of ∼2 × 108cm-2 and BSF density of ∼1 × 103cm-1. Despite an enhanced light extraction efficiency, the LED grown on PSS-GaN has two-times lower internal quantum efficiency than the LED grown on Bulk-GaN as determined by photoluminescence measurements. The LED grown on PSS-GaN substrate also has about two-times lower output power compared to the LED grown on Bulk-GaN substrate. This lower output power was attributed to the higher TDD and BSF density.

Experimental study on the wave measurements of wave buoys

Wave measurement is of vital importance for assessing the wave power resources and for developing wave energy devices, especially for the wave energy production and the survivability of the wave energy device. Wave buoys are one of the most popular measuring technologies developed and used for long-term wave measurements. In order to figure out whether the wave characteristics can be recorded by using the wave buoys accurately, an experimental study was carried out on the performance of three wave buoy models, viz two WaveScan buoys and one ODAS buoy, in a wave tank using the European FP7 MARINET facilities. This paper presents the test results in both time and frequency domains and the comparison between the wave buoys and wave gauge measurements. The analysis results reveal that for both regular and irregular waves, the WaveScan buoys have better performances than the ODAS buoy in terms of accuracy and the WaveScan buoys measurements have a very good correlation with those from the wave gauges.

An exploration of the impact of the Green-Schools programme on the development of sustainable behaviours in the home

Concern for the sustainability of our planet is widespread. The ever-increasing economic activity and large scale industralisation our consumer society requires has increased concerns among academics, politicians, and consumers alike on natural resource depletion, waste management, dangers of toxic chemicals, and climate change. Human consumption is causing major issues for the space we inhabit. Much work has been done over the past four decades to remedy human impact on our environment at corporate, policy and consumer level. But concerns on our ability to progress the sustainability agenda remain. Consumer behaviour plays a pivotal role in sustainable development. In light of this, we need to explore and understand the ways in which consumption occurs in consumers lives, with an aim to changing behaviours that do not support the natural environment. Questions on how to change consumer behaviour dominate much of the literature on sustainable consumption, but substantial behaviour change among individuals has not occurred as predicted. Some focus has shifted to look at upstream interventions, such as education. The Green-Schools Programme (known internationally as Eco-Schools) is one such intervention. The aim of this thesis was to explore consumption in the context of the Green-Schools Programme. The main research question asks: in the context of the Green-Schools, how are sustainable behaviour practices developed in the home? The findings presented in this thesis show that sustainable behaviour has developed in the home from both internal and external factors, the Green-Schools effect being one such factor; the programme does influence behaviour in the home context to some degree. One of the main findings of this research indicates that schoolchildren are imparting ‘positive pester power’ on household behaviour practices and the majority of households are passively practicing sustainable consumption. These findings contribute to knowledge on sustainable consumption in the home context.