Radiology--an exciting specialty, unsatisfactory training situation?

Despite the medical and technological advances during the last decade, there have been problems in attracting new recruits for radiology specialization in Norway. The increasing number of vacancies is a cause for concern. To address this problem, we held interviews with six residents--three males and three females aged between 30 and 39 years. They had from four months to three years of experience in diagnostic radiology at the time of the study. The data were analyzed according to the principles of Giorgi. The participants found radiology both interesting and challenging, but considered the specialist training inadequate, mainly because there were too many routine tasks and not enough supervision.     

Effect of viscosity and applied potential on oscillations at a Pt-Pt dual-electrode in a ferricyanide system

This paper outlines the effect of viscosity and applied potential on oscillations occurring at two platinum electrodes placed proximal to each other. Potential oscillations taking place on the primary electrode (WE1) under galvanostatic control in the ferricyanide system are affected by the solution viscosity as it modifies the convective feedback mechanism necessary for oscillations. Measured transition times correlate with those calculated using Sand equation thus allowing the estimation of current density windows for periodic oscillation for different solution viscosities for pre-determined transition times. Current oscillations on the secondary working electrode (WE2) - under potentiostatic control and induced by the potential oscillations on WE1 - can be tuned through the applied potential. At higher potentials the reaction is oxidation of [Fe(CN)₆]⁴⁻ and the coupling is primarily through the transfer of [Fe(CN)₆]⁴⁻ from WE1 to WE2 via H₂ evolution whilst at more cathodic potentials the reduction of [Fe(CN)₆]³⁻ takes place at both WE1 and WE2 and the convective feedback from WE1 refreshes the surface of both electrodes simultaneously.     

Effect of concentration polarization on the current-voltage characteristics of ion transfer across ities

Current-voltage characteristics of ion transfer across the ITIES was theoretically studied, taking concentration polarization into account through the Nernst-Planck equation in the diffusion boundary layers. In the inner layer transport was modelled using either Butler-Volmer or Nernst-Planck equations. Potential distribution across the ideally polarizable ITIES was calculated from the Poisson-Bolzman equation. The current-voltage curves were of the Butler-Volmer type, but no distinction between the two approaches inside the inner layer could be seen because the permeability of the entire system was determined by the diffusion boundary layers.     

Industrial ecosystem indicators—direct and indirect effects of integrated waste- and by-product management and energy production

In an idealised industrial ecosystem (IE), firms and organisations utilise each other's material and energy flows including wastes and by-products to reduce the system's virgin material and energy input as well as the waste and emission output from the system as a whole, and contribute to sustainable development (SD). IE complements the more conventional individual flow, product, process, organisation, individual actor or sector-focused environmental management approaches and tools with network or systems level approaches. The first research objective of this paper is to construct indicators for IE. The second task is to test the use of these indicators with "what if?" material and energy flow scenarios for the energy and waste system of Satakunta region in Finland including 28 municipalities. Using literature analysis as a source, we arrive at environmental indicators of carbon dioxide (CO₂) equivalents, and at economic indicators of fuel, energy and waste management costs and revenues. The social indicators show the employment effects of the waste management system. The scenarios analyse the current situation (0-scenario) against alternative situations in the future. The future scenarios are developed according to the known and anticipated trends in international and national policy and legislation. The indicator application in the scenarios produces social, environmental and economic effects of waste management in four categories: direct negative, direct positive, indirect negative and indirect positive. Industrial ecosystem theory emphasises the utilisation of wastes as a resource with value alongside the objective of reducing waste. Therefore, the indirect positive effects of waste management are important, as well as the conventional focus of waste management, which has usually been on direct positive effects. The main difficulties in our argument are the system boundary definition, the qualitatively different nature of environmental, economic and social effects and indicators as well as the lack of qualitative or interview data on the preferences and interests of the actors involved.     

Investigation of forced liquid flows in open capillary channels

We investigate a forced flow through an open capillary channel consisting of two parallel plates under microgravity condition. The aim of the experiments is to determine the maximal volume flux that can be withdrawn from the channel. The theoretical approach with a one-dimensional Bernoulli equation leads to a non-linear ordinary differential equation for the radius of curvature along the free surface of the channel. Both laminar and entrance pressure losses are taken into account as well as the flow conditions before the inlet of the channel. Several experiments with different channels and fluid properties were performed in the Bremen drop tower. The theory shows good agreement with the experimental data for a wide range of the non-dimensional parameters Ohnesorge number, gap ratio and channel length. The knowledge of the maximum volume flux is necessary to prevent gas ingestion at the channel outlet which is un-desired for applications in surface tension tanks.     

Carbon nanotubes as electrodes for dielectrophoresis of DNA

Dielectrophoresis can potentially be used as an efficient trapping tool in the fabrication of molecular devices. For nanoscale objects, however, the Brownian motion poses a challenge. We show that the use of carbon nanotube electrodes makes it possible to apply relatively low trapping voltages and still achieve high enough field gradients for trapping nanoscale objects, e.g., single molecules. We compare the efficiency and other characteristics of dielectrophoresis between carbon nanotube electrodes and lithographically fabricated metallic electrodes, in the case of trapping nanoscale DNA molecules. The results are analyzed using finite element method simulations and reveal information about the frequency-dependent polarizability of DNA.     

Waste Heat Recovery from a Marine Waste IncineratorUsing a Thermoelectric Generator

A marine waste incinerator has been evaluated for waste heat harvesting using thermoelectric generators (TEG). The application has been evaluated using mathematical modeling to optimize the heat exchanger and some vital design parameters of the TEG. The calculation shows that it is possible to extract 58?kW_el at a price of 6.6?US$/W from an 850-kW_th incinerator when optimizing for maximum power. However, minimizing the cost, it is possible to get 25?kW_el at a price of 2.5?US$/W. A trade-off between the two targets leads to a combination that gives 38?kW_el at a price of 2.7?US$/W.