Changing ideas of bodily cleanliness

The modern bathroom reflects Western ideas on the handling of bodily wastes, and consequently ideas of cleanliness. Taking a historical study as the point of departure, the purpose of this paper is to understand the extent to which the idea of cleanliness influences the possibility of converting the water closet to a more sustainable technology. An examination of historical changes demonstrates that our present ideas on cleanliness are distinct in their own way. It also demonstrates that our present ideas of cleanliness represent a drawing together of several loose ends, development towards which having been incoherent. Great variation has been apparent in practices surrounding, and the social importance of, cleanliness. People have lived in different ways and have had different ideas about how to behave. The Roman culture thought of bathing and relieving oneself as social duties. In the Middle Ages, uncleanliness ruled the day as people had a very natural and relaxed attitude to bodily waste. Following the urbanisation process, cleanliness was thought of as a step towards progress and a sanitational cure for epidemics in the cities. In more recent times, cleanliness became a project of orderliness and became institutionalised in society. The water closet is inextricably linked with our present ideas of cleanliness. This could impede a future conversion of the water closet, these ideas in several ways conflicting with the more sustainable toilet system. Nevertheless, it is also a point of this paper to illustrate that our present ideas of cleanliness are not self-evident. On the contrary, our ideas are contextually bound and might thus change, for instance, due to a strengthening of e.g. the environmental discourse

Danish bathroom stories – a socio-technical study of what the present renovation boom is about

This paper explores changes in ordinary daily behaviour in relation to bathroom renovations in Denmark. Much suggests that new expectations evolve in connection to such renovations and that these changes could have long-term environmental impacts. The aim of this paper is to get a deeper understanding of how the production and reproduction of cultural meanings are interconnected with the changes in the bathroom. On the basis of general remarks about cultural meanings in connection to the bathroom, I discuss some general characteristics of modern bathroom ideas. My point is to elucidate the simultaneous rootedness and contextual determination of bathroom ideas. Hereafter, I examine two empirical examples in order to study the actual process of bathroom renovations. Through this, I carry out an empirical unfolding of the interconnectedness of material, social and cultural dimensions in everyday life. These two examples show how cultural meanings connected to the bathroom are changed through the process. The bathroom setting changes, the informants’ rou-tines changes and the role of the bathroom changes. An example of new cultural meanings is how an element of pleasure is added to the idea of showering as a duty. The two examples also show how specific contexts trigger specific changes. In conclusion, the paper points out that renovations are part of a revolutionising of everyday life and its surroundings. Here, various contextual connec-tions are made and varying driving forces are at play. It also points out that new dimensions sup-plement the existing bathroom ideas during the renovation process. Finally, it raises the demand for a more thorough analysis of potential inherent long-term changes in our bathroom ideas

Inaccurate use of asymptotic formulas

The asymptotic form of the plane wave decomposition into spherical waves, which is used to express the scattering amplitude in terms of phase shifts, is incorrect. We explain why and show how to circumvent the mathematical inconsistency.Comment: 3 pages, version to appear in Am. J. Phy

Variational Integrators for Nonvariational Partial Differential Equations

Variational integrators for Lagrangian dynamical systems provide a systematic way to derive geometric numerical methods. These methods preserve a discrete multisymplectic form as well as momenta associated to symmetries of the Lagrangian via Noether's theorem. An inevitable prerequisite for the derivation of variational integrators is the existence of a variational formulation for the considered problem. Even though for a large class of systems this requirement is fulfilled, there are many interesting examples which do not belong to this class, e.g., equations of advection-diffusion type frequently encountered in fluid dynamics or plasma physics. On the other hand, it is always possible to embed an arbitrary dynamical system into a larger Lagrangian system using the method of formal (or adjoint) Lagrangians. We investigate the application of the variational integrator method to formal Lagrangians, and thereby extend the application domain of variational integrators to include potentially all dynamical systems. The theory is supported by physically relevant examples, such as the advection equation and the vorticity equation, and numerically verified. Remarkably, the integrator for the vorticity equation combines Arakawa's discretisation of the Poisson brackets with a symplectic time stepping scheme in a fully covariant way such that the discrete energy is exactly preserved. In the presentation of the results, we try to make the geometric framework of variational integrators accessible to non specialists.Comment: 49 page