Natural convection and the evolution of a reactive porous medium

We describe a mathematical model of buoyancy-driven flow and solute transport in a saturated porous medium, the porosity and permeability of which evolve through precipitation and dissolution as a mineral is lost or gained from the pore fluid. Imposing a vertically varying equilibrium solubility creates a density gradient which can drive convective circulation. We characterise the onset of convection using linear stability analysis, and explore the further development of the coupled reaction–convection system numerically. At low Rayleigh numbers, the effect of the reaction–permeability feedback is shown to be destabilising through a novel reaction–diffusion mechanism; at higher Rayleigh numbers, the precipitation and dissolution have a stabilising effect. Over longer time scales, reaction–permeability feedback triggers secondary instabilities in quasi-steady convective circulation, leading to rapid reversals in the direction of circulation. Over very long time scales, characteristic patterns of porosity emerge, including horizontal layering as well as the development of vertical chimneys of enhanced porosity. We discuss the implications of these findings for more comprehensive models of reactive convection in porous media

Death, mortality and religious diversity

Developed in partnership between the Immigration Museum and Deakin University, this exhibition examines how eight different groups in Victoria deal with death. It includes representatives of Moslem, Hindu, Christian (Catholic, Anglican, Greek Orthodox), Jewish, Buddhist faiths and those with no religion

Photoelectric tunable-step terahertz detectors: a study on optimal antenna parameters, speed, and temperature performance

Field effect transistors have shown promising performance as terahertz (THz) detectors over the past few decades. Recently, a quantum phenomenon, the in-plane photoelectric effect, was discovered as a novel detection mechanism in gated two-dimensional electron gases (2DEGs), and devices based on this effect, photoelectric tunable-step (PETS) THz detectors, have been proposed as sensitive THz detectors. Here, we demonstrate a PETS THz detector based on GaAs/AlGaAs heterojunction using a dipole antenna. We investigate the dependence of the in-plane photoelectric effect on parameters including the dimensions and the operating temperature of the device. Two figures of merit within the 2DEG, the maximum electric field and the radiation-induced ac-potential difference, are simulated to determine the optimal design of the PETS detector antenna. We identify the optimal antenna gap size, metal thickness, and 2DEG depth, and demonstrate the first PETS detector with a symmetric dipole antenna, which shows high-speed detection of 1.9 THz radiation with a strong photoresponse. Our findings deepen the understanding of the in-plane photoelectric effect and provide a universal guidance for the design of future PETS THz detectors

Space and loss: spirituality and symbolic connectedness in contemporary culture

This paper examines the significance of space in the experience, stories and memories of loss and grief. While for many religions the earth is an important element in rituals around birth, death and burial, in increasingly secular and multi-cultural societies, church and public cemeteries are no longer the dominant sacred sites, nor is religion the only way of defining &lsquo;spirituality&rsquo;. The paper describes shifts in religious and secular practices in dealing with loss and grief, presents case studies of traditional and contemporary frameworks in which ritual, storytelling and space are important elements of meaning making processes, and invites further examination of the ways in which artmaking restores a sense of control and meaning after the experience of loss. </div

Synthesis of pyrazoline derivatives and an examination of their local anaesthetic activity

(1) From p-alkoxy and m-p-dialkoxy benzylidene acetones, utilising the Mannich reaction, a series of unsaturated alkyl amino ketones of the type (I)has been prepared as hydrochlorides and the pyrazolines derived therefrom (II) have been synthesised and isolated as hydrochlorides or tartrates:(2) The new pyrazolines have been found to be potent local anaesthetics for topical and intradermal use.(3) In examining the topical activities on the cornea of guinea -pigs it was found that the effect of the size of the amino substituents on the ß-carbon atom of the 3 -ethyl group (i.e. the group NR") variedThe regression lines of the logarithms of the concentration against duration of topical anaesthesia have been found to be parallel in the case of all the pyrazolines and nupercaine. This last drug was therefore chosen as a suitable reference standard of activity. Cocaine, it was found however, could not be used for this purpose on account of the fact that the slope of the regression line in this case differ - :ed from that of the other drugs. This may be due to the fact that cocaine has a pronounced vaso- :constrictor activity.(4) The effect of change in size of the alkoxy groups substituted in the 5- phenyl nucleus on the topical activity has not been so fully examined, but it appears that the p -n- propoxy derivatives are the most active(5) The effect of changes in the size of the amino substituents of the ß-carbon in the 3-ethyl group on the intradermal activity of the drugs synthesised(6) The effect of the alkoxy substituents (R.O. and R'.0) upon the toxicity indicates that there is a slight decrease in toxicity with increase in size and number of alkoxy substituents(7) The effect of the amino substituents (N.R") upon toxicity has not been fully examined but the diethylamino compound is more toxic than the piperidino compound where the substituent in the 5-position is 3-methoxy-4-n-propoxy-phenyl

The Communication Department in a State of Perpetual Crisis: Discount Store University?

This article explores the implications of the discount store metaphor as it is commonly used and understood, and considers its implications for how academic departments are led and administered. The metaphor of the discount store is often offered as an implicit criticism of the legislators, trustees and administrators who demand that academic departments justify their curriculum and methods in financial terms. It is also sometimes offered as an implicit criticism of the students and parents who ask about the relevance or usefulness of course content, choose courses and majors with an eye to career and earning potential, complain about the high cost of tuition and books and demand that courses be scheduled around work and family obligations