A first principles study of methanol decomposition on Pd(111): Mechanisms for O-H bond scission and C-O bond scission

There is some dispute as to whether methanol decomposition occurs by O-H bond scission or C-O bond scission. By carrying out density functional theory calculations, we investigate both scenario of the reaction pathways of methanol decomposition on a Pd(111) surface. It is shown that the O-H bond scission pathway is much more energetically favorable than the C-O bond scission pathway. The high reaction barrier in the latter case is found to be due to the poor bonding abilities of CH3 and OH with the surface at the reaction sites. (C) 2001 American Institute of Physics.

Stepwise addition reactions in ammonia synthesis: A first principles study

Catalytic ammonia synthesis is believed to proceed via dissociation of N-2 and H-2 with subsequent stepwise addition reactions from an adsorbed nitrogen atom to NH3. The first step, N-2 dissociation, has been thoroughly studied. However, little is known about the microscopic details of the stepwise addition reactions. To shed light on these stepwise addition reactions, density functional theory calculations with the generalized gradient approximation are employed to investigate NHx (x=1,3) formation on Ru(0001). Transition states and reaction barriers are determined in each elementary step. It is found that the reaction barriers for stepwise addition reactions are rather high, for example, the barrier for NH hydrogenation is calculated to be 1.28 eV, which is comparable with that of N-2 dissociation. In addition, one of the stepwise addition reactions on a stepped surface is also considered. The reaction barrier is found to be much higher than that of N-2 dissociation on the same stepped surface, which indicates the importance of stepwise addition reactions in ammonia synthesis. (C) 2001 American Institute of Physics.

Coercion in the Community: A Situated Approach to the Examination of Ethical Challenges for Mental Health Social Workers

Increasingly, mental health social workers in the United Kingdom and elsewhere in the world are employing coercive interventions with clients. This paper explores this trend in the context of community-based settings, using national and international research literature on this subject. It begins with a discussion about the complex, contested nature of ideas on coercion. The authors then explore debates about how coercion is perceived and applied in practice. They choose two forms of coercion*/informal types of leverage, and the legally mandated use of Community Treatment Orders*/to highlight the range of ethical problems and dilemmas that confront practitioners in this field. The authors conclude by developing a tentative, explanatory model to explain how and why mental health social workers should consider a more holistic, situated approach to help deal with ethical concerns about the use of coercion.

Humanitarian Travels: Ethical Communication in Lonely Planet Guidebooks

Aside from the more mundane purpose of telling us where to eat, sleep and sightsee in foreign lands, guidebooks communicate an ethical vision that sees travel as the key to reducing cultural differences and inequalities. This article argues that Lonely Planet guidebooks in particular encourage a form of ‘responsible independent travel’ that both reflects and produces a powerful discourse of humanitarianism. By examining the controversy over Lonely Planet’s publication of guidebooks to Burma, this article uncovers the problematic colonial logic embedded in that ethical vision.