Supreme Emergencies and the protection of non-combatants in war

Is it ever justifiable to target non-combatants deliberately? This article assesses Michael Walzer's claim that the deliberate targeting of non-combatants may be justifiable during 'supreme emergencies', a view that has received some support but that has elicited little debate. It argues that the supreme emergencies exception to the prohibition on targeting non-combatants is problematic for at least four reasons. First, its utilitarianism contradicts Walzer's wider ethics of war based on a conception of human rights. Second, the exception may undermine the principle of non-combatant immunity. Third, it is based on a historical fallacy. Finally, it is predicated on a strategic fallacy-the idea that killing noncombatants can win wars. The case for rejecting the exception, however, has been opposed by those who persuasively argue that it is wrong to tie leaders' hands when they confront supreme emergencies. The final part of the article addresses this question and suggests that the principle of proportionality may give political leaders room for manoeuvre in supreme emergencies without permitting them deliberately to target non-combatants.

Influence of adsorbate interaction on transport in confined spaces

This article provides a review of the recent theory of transport in nanopores developed in the author's laboratory. In particular the influence of fluid-solid interactions on the transport coefficient is examined, showing that such interactions reduce the value of the coefficient by almost an order of magnitude in comparison to the Knudsen theory for non-interacting systems. The activation energy and potential energy barriers for diffusion in smooth pores with a one-dimensional potential energy profile are also discussed, indicating the inadequacy of the commonly used assumption of proportionality between the activation energy and heat of adsorption or the minimum pore potential energy. A further feature affected by fluid-solid interactions is the nature of the reflection of fluid molecules colliding with a pore wall surface, varying from being nearly specular - such as in carbon nanotubes - to nearly diffuse for amorphous solids. Diffuse reflection leads to momentum loss and reduced transport coefficients. However, fluid-solid interactions do not affect the transport coefficient in the single-file diffusion regime when the surface reflection is diffuse, and the transport coefficient in this case is largely independent of the adsorbed density.

Student Difficulties with units in differential equations in modelling contexts

First-year undergraduate engineering students' understanding of the units of factors and terms in first-order ordinary differential equations used in modelling contexts was investigated using diagnostic quiz questions. Few students appeared to realize that the units of each term in such equations must be the same, or if they did, nevertheless failed to apply that knowledge when needed. In addition, few students were able to determine the units of a proportionality factor in a simple equation. These results indicate that lecturers of modelling courses cannot take this foundational knowledge for granted and should explicitly include it in instruction.