Involving Others: Towards an Ethical Concept of Risk

Dr. Rehman-Sutter argues for a juridical concept of risk as it relates to an ethic of care. He also contrasts his view with traditional economic risk analysis

Coincidence site modules in 3-space

The coincidence site lattice (CSL) problem and its generalization to Z-modules in Euclidean 3-space is revisited, and various results and conjectures are proved in a unified way, by using maximal orders in quaternion algebras of class number 1 over real algebraic number fields.Comment: 25 page

Eddy diffusivity near bubble plumes

Profiles of eddy diffusivity and the rate of dissipation of temperature variance were inferred from temperature microstructure measurements near a bubble plume at the center of a tank with a diameter of 13.7 m and a maximum depth of 8.3 m. Measurements occurred outside the bubbly part of the flow. Profiles of eddy diffusivity were estimated with two methods: one based on the equation for turbulent kinetic energy and one based on the equation for temperature variance. The eddy diffusivities showed nonmonotonic behavior with distance from the plume axis, as in numerical simulations. Eddy diffusivities estimated with the two methods match well, except for one data set with strong turbulence and weak stratification. The estimates of the eddy diffusivity allow two empirical formulas for the bulk, or tank-averaged, effective diffusivity to be evaluated; the bulk diffusivity is within the range of values predicted by the models

Theory for differential transport of scalars in sheared stratified turbulence

Scalars with different molecular diffusivities can be transported at different rates in a strongly stratified, weakly turbulent flow. Rapid distortion theory (RDT) is used to examine the mechanisms responsible for differential diffusion of scalars in a sheared stratified flow. The theory, which applies when the flow is strongly stratified, predicts upgradient flux and its wavenumber dependence, which previous direct numerical simulations have shown to be important in differential diffusion. The net effect of shear on differential diffusion depends on the Grashof number, or the relative importance of buoyancy and viscous effects. RDT also allows the effects of the density ratio, Schmidt number, Lewis number, scalar activity and mean shear to be examined without the high computational cost of direct numerical simulation. RDT predicts that differential diffusion will increase with increasing density ratio, but only at low Grashof number. When the Lewis number is fixed, the Grashof number below which differential diffusion occurs decreases with increasing Schmidt number, and when one of the Schmidt numbers is fixed, differential diffusion decreases with increasing Lewis number. Also, differential transport of passive scalars increases when the Schmidt number of the scalar stratifying the flow increases

The simulation of ionospheric conditions for space vehicles

Plasma wind tunnel to simulate ionospheric conditions for space vehicle

Ideology-Critique with the Conceptual Hinterland of a Theory of the Ideological

The ‘ideology-theoretical turn’ of the late 1970s and 1980s claimed a re- foundation of Marxist research into ideology, which was stuck in several respects. Its attempt to overcome the traditional fixation on a criticism of ‘false’ consciousness is still valid. It led, however, in particular in the tradition of the Althusser School, to an over-general notion of ideology that repressed the radical and critical impulses of Marx and Engels’ concept of ideology. Going deliberately against the grain of a predominant tendency in secondary literature, which places Marx/Engels’ and Gramsci’s concepts of ideology on opposite poles of the spectrum, the essay shows that the strength of the respective approaches lies in their particular combination of ideology- critique and ideology-theory. The dichotomy of these strands is misguided and counterproductive and needs to be overcome by the renewal of an ideology- critique which is informed and backed up by a materialist theory of the ideological

Transport by an intrusion generated by boundary mixing in a lake

A dye study was conducted to track an intrusion generated at the boundary of a small lake. Persistent turbid layers offshore presented evidence of possible intrusions from boundary mixing. After high winds, a streak of Rhodamine WT was injected at the boundary of the lake where the slope was between 5% and 10%. Both vertical profiles and longitudinal transects of the dye concentration were measured. The three-dimensional dye mapping showed a distinct dye intrusion, ranging between 0.5 and 1 m thick, over 200 m in horizontal extent offshore, 1 day after the injection. Profiles of temperature microstructure measured soon after the injection both at the injection site and offshore showed an elevated eddy diffusivity near the boundary where the dye was injected, indicating that the intrusion resulted from boundary mixing. Because the dominant internal waves are subcritical, the mixing is most likely due to seiching currents interacting with the boundary. The propagation characteristics of the intrusion were predicted most closely by a formulation for a radially spreading intrusion governed by a balance between buoyancy and inertia. These results show that intrusion generation and propagation may be a significant process for mass transport in stratified lakes and reservoirs