Editorial: Sustainable Waste Management Innovations: Developing New Ventures for Improved Health and Environmental Wellbeing

In this Editorial, we synthesise the articles in the Special Issue with unique insights into sustainable waste management innovations and sustainable business practices [...

Global Sustainability Under Uncertainty: How Do Multinationals Craft Regulatory Policies?

Multinational corporations are increasingly mindful of the significance of sustainability transitions and the need for operations that are energy efficient and environmentally sound. Achieving sustainability under conditions of uncertainty entails the involvement of multiple stakeholders in initiating and carrying outsustainability-focused initiatives. Using longitudinal analysis of Royal Dutch Shell’s sustainability policies, we developed an integrated model to elucidate how uncertainty influences sustainability policies in the specific context of multinational corporations (hereinafter – MNCs). We identified three phases in theevolution of Shell’s sustainability innovation: a self-reflective phase (2000–2003) characterized by intense pressure from climate advocacy groups, an investment phase (2004–2006) for which the MNC attempted to rise to the waste disposal and pollution challenge through renewable sources of energy, and a reorganization phase (2007–2010) to streamline operations. We also uncovered themes that influence how regulatory policies are crafted: responding positively to the “community’s voice”, risk spreading through joint ventures, revenue transparency for government accountability and reporting innovation that confronts hard truths. The practical implications are outlined

Biexcitonic absorption in a disk-shaped GaN quantum dot

The present work investigates the nonlinear optical properties of a GaN quantum dot in the disk limit via the exciton and biexciton states using the compact density matrix formalism. Based on this model, we calculate the ground state energy of the exciton and biexciton states by the variation method, within envelope function and effective mass approximations. Linear and nonlinear optical absorption (α(1), α(3)) and oscillator strengths attributed to the optical transitions are obtained. The details of the behaviour of α(1) and α(3) around the resonance frequencies and for different quantum dot geometries are presented. It is found that the size of quantum dot and the optical intensity have a remarkable effect on the optical absorption, and the biexcitonic two-photon absorption coefficient(K2) has also been calculated in this system. The results show that this parameter is strongly affected by the size of the quantum dot