The isolation and characterisation of human globin and interferon genes

Imperial Users onl

Demonstration of sustained and useful converter responses during balanced and unbalanced faults in microgrids

In large power grids where converter penetration is presently low and the network impedance is predominantly reactive, the required response from converters during faults is presently specified by phrases such as “maximum reactive output”. However, in marine and aero power systems most faults are unbalanced, the network impedance is resistive, and converter penetration may be high. Therefore a balanced reactive fault current response to an unbalanced fault may lead to over-voltages or over/under frequency events. Instead, this paper presents a method of controlling the converter as a balanced voltage source behind a reactance, thereby emulating the fault response of a synchronous generator (SG) as closely as possible. In this mode there is a risk of converter destruction due to overcurrent. A new way of preventing destruction but still providing fault performance as close to a SG as possible is presented. Demonstrations are presented of simulations and laboratory testing at the 10kVA 400V scale, with balanced and unbalanced faults. Currents can be limited to about 1.5pu while still providing appropriate unbalanced fault response within a resistive network

The importance of collaboration and competition within and outside the OECD

The purpose of this paper is to address the role of the OECD in the global marketplace. The paper highlights some current trends in the global market and the changing role of the OECD. In this context, the authors discuss various perspectives on the role of OECD in a globalized world. The authors focus on recent debates on the state of the global economy and the changing position of the OECD in the world market. The authors apply a conceptual approach combined with analyses of data and secondary material. The authors also put forward an argument for investigating what determines competition within and outside the OECD. In this context, creating markets within a global economy requires considerable stimulus on the part of national governments. This necessitates national governments working together in partnership with national and global firms to reduced bureaucracy and increase transparency to boost trade in a cost effective manner. This is seen by some economists to be a prerequisite to future competitiveness. Finally, the authors seek to demonstrate how leading countries within the OECD are building innovative capability to master the challenges and opportunities that the new emerging economies present (such as Brazil)

Economic shifts: reconciling observations and rhetoric within the U.S. economy

For the American people, déjà vu arrived in December 2007, and for the former President of the United States, Barack Obama, it was when he was inaugurated on 20 January 2009, inheriting the worst financial crisis since the Great Depression of 1929. At the start of the 2007, financial crisis the United States (U.S.) was experiencing a boom in consumer spending. This came to an abrupt halt when the U.S. housing market collapsed resulting in an $8 trillion dollar housing debt and a steep decline in equity prices. Fallout from the housing crisis quickly spread to the broader economy through a complex web of unclear financial instruments tied to housing and dubious business practices of some financial firms. The resulting loss of wealth led to cutbacks in U.S. credit backed consumer spending. According to the U.S. Department of Labour1, roughly, 8.7 million jobs were shed from February 2008 to February 2010, and GDP contracted by 5 percent, making this the Great Recession the worst since the Great Depression