193 research outputs found
Habitat richness and tree species richness of roundabouts: effects on site selection and the prevalence of arboreal caterpillars
This study examined the relationship between the habitat and tree species richness of roundabouts and the abundance and species richness of tree-dwelling caterpillars, and thus the potential of urban roundabouts to support breeding populations. Total tree species number on sites was related to an increase in caterpillar abundance and a greater number of habitats was associated with a higher number of caterpillar species. An increase in the total number of trees was not correlated with a greater abundance of tree-feeding Lepidoptera; nor were native trees found to support proportionally more caterpillar species than all tree species, including introduced. This could be due to differences in species accumulation, the prevalence of generalist species or a statistical sampling effect. The occupancy and average abundance of caterpillar species was generally low, which does not support the theory that Lepidoptera in urban areas tend towards mono-dominance. It may, however, represent the presence of âaccidentalâ species on roundabouts. Habitat management and planting to increase tree species diversity and density on roundabouts has the potential to increase the species diversity and abundance of arboreal Lepidoptera, and increase abundance of butterfly and moth urban populations
Effect of Nanoclay Content on Void Morphology in Resin Transfer Molded Composites
Effects of nanoclay content on morphology and spatial distribution of voids in resin transfer molded nanoclay/E-glass/epoxy composite disks are investigated. ClositeÂź25A nanoclay loads of 2, 5, and 10wt% are mixed by sonication with a low-viscosity epoxy resin prior to filling the mold cavity containing 13.6% E-glass preform by volume. A disk without nanoclay is also molded. Once the molded composites are cured, voids on radial composite samples are evaluated via microscopic image analysis. The addition of nanoclay is found to result in a significant increase in the apparent viscosity of the clay-epoxy mixture, thus increasing the molding pressure. Void occurrence is observed to increase considerably with increasing nanoclay content, from 2.1% in the composite without nanoclay to 5.1 and 8.3% in the composites molded with 5 and 10wt% nanoclay, respectively. However, the composite with 2wt% nanoclay yields the lowest void content of 0.7%. Voids are observed to be, in average, smaller after the addition of nanoclay at all nanoclay concentrations. Presence of nanoclay in the impregnating resin induces at least 60% reduction in voids located inside fiber tows, which are trapped by the fluid front motion during impregnation. Irregularly shaped voids are also observed to decrease with increasing nanoclay content. A nonuniform void content and morphology is observed radially, which seems to be affected by the flow kinematics as well as possible breakdown and filtration of clay clusters.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
Complete genome sequence of Granulicella mallensis type strain MP5ACTX8T, an acidobacterium from tundra soil
Granulicella mallensis MP5ACTX8(T) is a novel species of the genus Granulicella in subdivision 1of Acidobacteria. G. mallensis is of ecological interest being a member of the dominant soil bacterial community active at low temperatures and nutrient limiting conditions in Arctic alpine tundra. G. mallensis is a cold-adapted acidophile and a versatile heterotroph that hydrolyzes a suite of sugars and complex polysaccharides. Genome analysis revealed metabolic versatility with genes involved in metabolism and transport of carbohydrates. These include gene modules encoding the carbohydrate-active enzyme (CAZyme) family involved in breakdown, utilization and biosynthesis of diverse structural and storage polysaccharides including plant based carbon polymers. The genome of Granulicella mallensis MP5ACTX8(T) consists of a single replicon of 6,237,577 base pairs (bp) with 4,907 protein-coding genes and 53 RNA genes
Improving rail wear and RCF performance using laser cladding
Laser cladding has been considered as a method for improving the wear and RCF performance of standard grade rail. This paper presents results of small scale tests carried out to assess the wear and RCF performance of rail which had been laser clad. Using the laser cladding process premium metals can be deposited on to the working surface of standard rail with the aim of enhancing the wear and RCF life of the rail. Various laser clad samples were tested using a twin-disc method. The candidate metals were clad on to standard R260 grade rail discs and were tested against a disc of standard wheel material. During the tests, wear rates and RCF initiation were monitored and compared to those of a standard rail disc. Six candidate cladding materials were chosen for this test: A multi-phase Manganese Steel Variant (MMV), Martensitic Stainless Steel (MSS), TWIP Steel, NiCrBSi, Stellite 12 and Stellite 6. The MSS, Stellite 6, and Stellite 12 samples showed reduced wear rates relative to the standard R260 Grade rail discs, and also produced a reduction in wheel steel wear. The RCF initiation resistance of all of the candidate materials was superior compared to the R260 Grade material
Study of a Depolarizing Resonance at the IUCF Cooler Ring
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
Carotenoid content and reflectance of yellow and red nuptial plumages in widowbirds (Euplectes spp.)
1. Ornamental carotenoid coloration is commonly based on several different pigments with different nutritional and metabolic constraints. The identification and quantification of carotenoid pigments is therefore crucial to the understanding of signal content and signal evolution. 2. In male widowbirds (Euplectes spp.), the striking yellow and red carotenoid colours have been measured by reflectance spectrometry and studied with respect to sexual selection through male contest competition, but their biochemical mechanisms have not been analysed. 3. Here we use reflectance analysis and high performance liquid chromatography (HPLC) to describe the species-specific colours and plumage carotenoids in three widowbird species: yellow-mantled widowbird (YMW) Euplectes macrourus, red-shouldered widowbird (RSW) E. axillaris and red-collared widowbird (RCW) E. ardens. 4. YMW yellow (âhueâ colorimetric λR50 = 522 nm) derives from the two âdietary yellowâ xanthophylls lutein and zeaxanthin, together with small amounts of âderived yellowâ pigments (3âČ-dehydrolutein and canary xanthophylls). 5. RCW red (λR50 = 574 nm) is achieved by the addition of low concentrations of âderived red â 4-keto-carotenoids, notably α- and ÎČ-doradexanthin and canthaxanthin. 6. RSW red (λR50 = 589 nm) is, in contrast, created by high concentrations of âdietary yellow â pigments (lutein, zeaxanthin) and âderived yellow â anhydrolutein, the latter only recently described in birds. 7. The two different mechanisms of producing red plumage are compared with other bird species and discussed with regard to costs and signal âhonestyâ
Full-scale testing of laser clad railway track; case study - testing for wear, bend fatigue and insulated block joint lipping integrity
This paper reports on a series of tests which were carried out on full-scale sections of rail that
had been treated by laser cladding aiming to create a layer (~1-2mm) of high performance
material on the rail head. Experiments were designed to measure wear, lipping of insulated
block joints (IBJs) and bending fatigue of clad samples. The wear rate of the clad samples was
between 78- 89% lower than that of the standard R260 reference sample. Cladding of either
side of an insulated block joint greatly improves its lipping resistance and allows it to withstand
approximately 3 times the energy input into the contact compared to a standard un-clad IBJ. A
section of rail clad with martensitic stainless steel was subject to bend fatigue testing and ran
out to 5,000,000 cycles at a stress range of 350 MPa matching the performance of an unclad
R260 rail. Although there is no standard for the bend testing of laser clad rail this performance
exceeds the performance requirements of the NR/SP/TRK111 standard which governs the bend
testing of flash but welded rail
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