13,319 research outputs found
Global dimensions for the recognition of prototypical urban roads in large-scale vector topographic maps
CISRG discussion paper ; 1
Craze initiation and growth in rigid PVC
The approach adopted here has been to look for discontinuities
in the deformation behaviour of UPVC and to attempt to correlate these
with the brittle failure process. This approach has the premise that
deformation and the initiation of the failure process have a strong
interaction, i.e. one perturbs the other. Evidence to support this
interaction in UPVC (and other glassy amorphous polymers) is abundant.
The connecting link between deformation and failure could well be craze
initiation and growth
Suppressed silicide formation in FePt thin films by nitrogen addition
Copyright © 2013 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Journal of Magnetism and Magnetic Materials. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Magnetism and Magnetic Materials Vol. 331 (2013), DOI: 10.1016/j.jmmm.2012.11.045FePt and FePtN thin films have been prepared on silicon substrates by the relatively new deposition technique known as High Target Utilization Sputtering. Films were annealed post-deposition at temperatures up to 800 °C in order to induce the high-anisotropy L10 phase. The FePt films initially showed an improvement in magnetic properties with annealing temperature, but for annealing above around 400 °C the magnetic properties deteriorated markedly. The magnetic properties of the FePtN films, however, continued to improve with increasing annealing temperature, right up to the maximum temperature applied of 800 °C. Analysis by X-ray diffraction revealed the formation of iron and platinum silicides in FePt films above 400 °C, but that such silicides are absent from the FePtN at all annealing temperatures except 800 °C. This behavior is attributed to the nitrogen in FePtN films reacting preferentially with the silicon in the substrate to form silicon nitride, thus suppressing the formation of platinum and iron silicides. Thus, by introducing nitrogen during the deposition of FePt films on Si substrates the formation of deleterious silicides appears to be suppressed during thermal treatment, thereby offering protection against silicon pollution.Plasma Quest Lt
The effect of within-crop habitat manipulations on the conservation biological control of aphids in field-grown lettuce
Within-crop habitat manipulations have the potential to increase the biological
control of pests in horticultural field crops. Wildflower strips have been shown to
increase the abundance of natural enemies, but there is little evidence to date of an
impact on pest populations. The aim of this study was to determine whether withincrop
wildflower strips can increase the natural regulation of pests in horticultural
field crops. Aphid numbers in plots of lettuce grown adjacent to wildflower strips
were compared with those in plots grown in the absence of wildflowers. The presence
of wildflower strips led to a decrease in aphid numbers on adjacent lettuce plants
during June and July, but had less impact in August and September. The decrease in
aphid numbers was greatest close to the wildflower strips and, the decrease in aphid
numbers declined with increasing distance from the wildflower strips, with little
effect at a distance of ten metres. The main natural enemies found in the crop were
those that dispersed aerially, which is consistent with data from previous studies on
cereal crops. Analysis and interpretation of natural enemy numbers was difficult due
to low recovery of natural enemies, and the numbers appeared to follow changes in
aphid abundance rather than being directly linked to the presence of wildflower
strips. Cutting the wildflower strips, to remove floral resources, had no impact on the
reduction in aphid numbers achieved during June and July, but decreased the effect
of the wildflower strips during August and September. The results suggest that
wildflower strips can lead to increased natural regulation of pest aphids in outdoor
lettuce crops, but more research is required to determine how this is mediated by
natural enemies and how the impact of wildflower strips on natural pest regulation
changes during the growing season
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