Fumigant toxicity of essential oils from the Myrtaceae family and 1,8-cineole against 3 major stored-grain insects

Six out of 42 essential oils extracted from species of the family Myrtaceae found in Australia were shown to have potent fumigant toxicity against three major stored-grain insects: Sitophilus oryzae, Tribolium castaneum and Rhyzopertha dominica. These were the essential oils from Eucalyptus nicholii, E. codonocarpa, E. blakelyi, Callistemon sieberi, Melaleuca fulgens and M. armillaris. The LD₅₀ and LD₉₅ of the selected essential oils against S. oryzae adults were between 19.0–30.6 and 43.6–56.0 μl/l air, respectively. Also, these oils were approximately twice as toxic to T. castaneum and R. dominica at the LD₉₅. Fumigant effects of the essential oils rich in 1,8-cineole were considered to warrant further research into their potential for commercial use.     

Theoretical and numerical aspects of transmit SENSE

The ideas of parallel imaging techniques, designed to shorten the acquisition time by the simultaneous use of multiple receive coils, can be adapted for parallel transmission of a spatially selective multidimensional RF pulse. In analogy to data acquisition, a multidimensional RF pulse follows a certain trajectory in k-space. Shortening this trajectory shortens the pulse duration. The use of multiple transmit coils, each with its own time-dependent waveform and spatial sensitivity, compensates for the missing parts of k-space. This results in a maintained spatial definition of the pulse profile while its duration is reduced. This paper describes the basic equations of parallel transmission with arbitrarily shaped transmit coils ("Transmit SENSE") focusing on two-dimensional RF pulses. Results of numerical studies are presented demonstrating the theoretical feasibility of the approach.     

Intelligente Roboter — 2. Österreichisch-Koreanisches Gemeinschaftsseminar

Ohne Zusammenfassung     

Severe accidents in the energy sector: comparative perspective

This paper addresses one of the controversial issues in the current comparative studies of the environmental and health impacts of energy systems, i.e. the treatment of severe accidents. The work covers technical aspects of severe accidents and thus primarily reflects an engineering perspective on the energy-related risk issues, though some social implications are also touched upon. The assessment concerns fossil energy sources (coal, oil and gas), nuclear power and hydro power. The scope is not limited to the power production (conversion) step of these energy chains but, whenever applicable, also includes exploration, extraction, transports, processing, storage and waste disposal. With the exception of the nuclear chain the focus of the work has been on the evaluation of the historical experience of accidents. The basis used for this evaluation is a comprehensive database ENSAD (Energy-related Severe Accident Database), established by the Paul Scherrer Institut (PSI). For hypothetical nuclear accidents the probabilistic technique has also been employed and extended to cover the assessment of economic consequences of such accidents. The broader picture obtained by coverage of full energy chains leads on the world-wide basis to aggregated immediate fatality rates being much higher for the fossil chains than what one would expect if only power plants were considered. Generally, the immediate fatality rates are for all considered energy carriers significantly higher for the non-OECD countries than for OECD countries. In the case of hydro and nuclear the difference is in fact dramatic. The presentation of results is not limited to the aggregated values specific for each energy chain. Also frequency-consequence curves are provided. They reflect implicitly the ranking based on the aggregated values but include also such information as the observed or predicted chain-specific maximum extents of damages. This perspective on severe accidents may lead to different system rankings, depending on the individual risk aversion.     

Large-scale grid-enabled lattice Boltzmann simulations of complex fluid flow in porous media and under shear

Well-designed lattice Boltzmann codes exploit the essentially embarrassingly parallel features of the algorithm and so can be run with considerable efficiency on modern supercomputers. Such scalable codes permit us to simulate the behaviour of increasingly large quantities of complex condensed matter systems. In the present paper, we present some preliminary results on the large-scale three-dimensional lattice Boltzmann simulation of binary immiscible fluid flows through a porous medium, derived from digitized X-ray micro-tomographic data of Bentheimer sandstone, and from the study of the same fluids under shear. Simulations on such scales can benefit considerably from the use of computational steering, and we describe our implementation of steering within the lattice Boltzmann code, called LB3D, making use of the RealityGrid steering library. Our large-scale simulations benefit from the new concept of capability computing, designed to prioritize the execution of big jobs on major supercomputing resources. The advent of persistent computational grids promises to provide an optimal environment in which to deploy these mesoscale simulation methods, which can exploit the distributed nature of computer, visualization and storage resources to reach scientific results rapidly; we discuss our work on the grid-enablement of lattice Boltzmann methods in this context.     

Fast liquid-crystal elastomer swims into the dark

Liquid-crystal elastomers (LCEs) are rubbers whose constituent molecules are orientationally ordered. Their salient feature is strong coupling between the orientational order and mechanical strain. For example, changing the orientational order gives rise to internal stresses, which lead to strains and change the shape of a sample. Orientational order can be affected by changes in externally applied stimuli such as light. We demonstrate here that by dissolving-rather than covalently bonding-azo dyes into an LCE sample, its mechanical deformation in response to non-uniform illumination by visible light becomes very large (more than 60 degrees bending) and is more than two orders of magnitude faster than previously reported. Rapid light-induced deformations allow LCEs to interact with their environment in new and unexpected ways. When light from above is shone on a dye-doped LCE sample floating on water, the LCE 'swims' away from the light, with an action resembling that of flatfish such as skates or rays. We analyse the propulsion mechanism in terms of momentum transfer.     

Stabilization of single-wall carbon nanotubes in fully sulfonated polyaniline

The interaction of single wall carbon nanotubes (SWNT) with an aqueous solution of the fully sulfonated polyaniline poly(2-methoxyaniline-5-sulfonic acid) (PMAS) and (+)-1-phenylethylamine (PhEA) has been investigated using spectroscopic methods. UV-vis spectral measurements show that the PMAS backbone undergoes conformational changes upon interaction with both SWNT and PhEA. Partial intercalation of PMAS into SWNTbundles was confirmed by Raman spectroscopy and electron microscopy.     

Classroom posture and self-reported back and neck pain in schoolchildren

The study reported here aims to identify the extent of back pain experienced by 11-14 year old schoolchildren, and establish the intensity, duration and frequency of exposure to physical risk factors present in schools. This paper considers the sitting postures of schoolchildren in the classroom. The sitting postures of 66 children were recorded in normal lessons using the Portable Ergonomic Observation Method (PEO). The study found significant associations between flexed postures and low back pain. Static postures and neck and upper back pain were also associated. This study has implications for schools, designers and people in the field of work related musculoskeletal disorders. Further research is required to examine the association between sitting posture and pain reported at different spinal locations.