Microhollow Cathode Discharges

The current–voltage characteristics of hollow cathode discharges and their predischarges in argon under dc and pulsed conditions were found to have a positive slope at pressures up to approximately 50 Torr, and currents up to 20 mA, at a hole diameter of 0.7 mm. In this range of pressure and current, parallel operation of hollow cathode discharges, without ballast, was demonstrated. Scaling to higher pressure is possible by reducing the hole diameter. Pulsed experiments with an array of cathode rings of 75 μm diameter allowed us to obtain parallel operation of more than 50 discharges at a pressure of 350 Torr in air

Global environmental agreement-making: upping the methodological and ethical stakes of studying negotiations

This perspective identifies how recent advances contribute to re-evaluating and re-constructing global environmental negotiations as a research object by calling into question who constitutes an actor and what constitutes a site of agreement formation. Building on this scholarship, we offer the term agreement-making to facilitate further methodological and ethical reflection. The term agreement-making broadens the conceptualisation of the actors, sites and processes constitutive of global environmental agreements and brings to the fore how these are shaped by, reflect and have the potential to re-make or transform the intertwined global order of social, political and economic relations. Agreement-making situates research within these processes, and we suggest that enhancing the methodological diversity and practical utility is a potential avenue for challenging the reproduction of academic dominance. We highlight how COVID-19 requires further adapting research practices and offers an opportunity to question whether we need to be physically present to provide critical insight, analysis and support

Governance and Measures for the Prevention of Marine Debris

Marine microplastic pollution is increasingly seen as a transboundary problem that requires priority attention and represents a unique governance challenge, given the associated risks and ubiquity of microplastics in the marine environment. Various governance measures to reduce the use of microplastics and to prevent further pollution of the marine environment have been adopted or are under consideration by actors at different levels of governance. This chapter reviews these governance measures and we argue that the primary concern of regulators should be to prevent both primary and secondary microplastic leakage into the marine ecosystems. We proceed with the further assumption that most microplastic enters marine ecosystems from land-based sources, so policies designed to curtail this particular form of plastic pollution are given due emphasis in this chapter. The prevention of microplastic pollution in the oceans is inherently complex, and this chapter examines the governance framework on the global, regional, national, and subnational levels. Both international collaboration and complimentary governance by non-state actors are important in order to effectively prevent microplastic pollution entering the oceans. Evidence from the examples analyzed throughout the chapter confirms that a comprehensive, systems-level approach, including a combination of diverse prevention measures and the involvement of a wide range of actors, is necessary