Effect of Mixture Pressure and Equivalence Ratio on Detonation Cell Size for Hydrogen-Air Mixtures

Cell sizes of fuel and oxidizer combinations are the fundamental length scale of detonations. The detonation cell size is correlated to dynamic detonation properties. One of the properties, detonability is the motivation for this research. In order to design combustion chambers for detonating engines, specifically PDEs and RDEs, the cell size is needed. Higher than atmospheric mixture pressure detonation cell sizes are important for scaling the combustion chambers, and before this research no data existed for hydrogen and air detonation cell sizes at mixture pressures up to 10.0 atm. This research successfully validated a new detonation cell size measurement technique and measured 15 cases for varying mixture pressures up to 10 atm and equivalence ratios. The results were concurrent with previous trends, as increase in mixture pressure decreased detonation cell size and a decrease in equivalence ratio from stoichiometric increased detonation cell size. The experimental results were used to establish a correlation that estimates hydrogen and air detonation cell size given initial mixture pressure and equivalence ratio

Reflections on the legitimacy of regional environmental governance: Lessons from Australia's experiment in natural resource management

The regional arrangements emerging for environmental governance in Australia mark a substantial change in the relationship between the state and civil society. Central to these arrangements is a transfer of responsibilities for natural resource management to regional communities. Although partnerships and other collaborative approaches have been embraced as a more democratic and effective means of addressing Australia's environmental problems, the legitimacy of these arrangements has been given insufficient attention. In particular, as central governments have retained significant influence in the setting of regional priorities and the accreditation of regional plans, there is a need to examine the relationships between 'old' and 'new' forms of governing. This paper critically examines the sources of legitimacy that underpin these relationships by drawing on interviews with regional actors in Central Queensland. This analysis demonstrates the hybrid nature of legitimacy, justified via traditional sources of legitimate authority alongside participatory and deliberative norms. This hybridity underlines the importance of attending to all dimensions of legitimacy in the design of governance arrangements. Residual issues of exclusion, and the discounting of community members' substantive concerns, mean that harnessing the mutuality gains derived from local knowledge and experience remains a core challenge for the legitimacy of environmental governance