364 research outputs found

    Increasing gas sorption onto carbon by milling with alumina

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    Graphite milled alone for 50 h shows an increase in gas sorption of a factor of three over unmilled powder. When graphite is milled in the presence of a much harder phase, aluminium oxide, the increase in sorption is much greater with a seven fold increase achieved after 5 h milling. Extending the milling time resulted in increased capacity; an estimated capacity of 2.5 g/ g carbon was achieved after 50 h milling

    Comparative study of mechanical activation of molybdenite (MoS2) with and without magnesium (Mg) addition

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    Molybdenite concentrate was mechanically activated in the presence of magnesium metal using a planetary mill in order to try to form elemental molybdenum. A sample milled for 90 min in planetary mill showed almost the same structural distortion as after 50 h in a tumbling mill, neither showed the presence of molybdenum metal. However, molybdenite milled together with magnesium showed more amorphization than separately milled molybdenite. Despite the apparent lack of reaction, molybdenite showed higher solubility in dilute HCl after milling with magnesium than without.Mongolian Journal of Chemistry 16 (42), 2015, 30-3

    Effect of extended ball milling on graphite

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    Graphite has been milled for up to 1000 h in a laboratory scale tumbling ball mill under vacuum. Raman spectroscopy of the powders indicated the increasing dominance of D-type graphitic sp bonding over G-type bonding with increasing milling time. Diamond-like sp bonding and possibly fullerene-like bonding also became evident after milling. TEM of the 100 h sample showed the presence of ribbons which were composed of sheets showing defects, delamination, translation, warping and curvature. Interplanar spacings of 0.40–0.50 nm were measured with the spacing increasing towards the edge of the ribbons where delamination was evident. Thermogravimetric analysis in argon of the powder after exposure to air showed an increasing mass loss with milling time indicating the presence of chemisorbed gas. Using TG–FTIR the gas was found to be a mixture of CO and an unidentified gas (probably oxygen). BET surface area measurements showed a maximum in the surface area; however, this was shown to be massively in error for the longer milling times due to the presence of the chemisorbed gas

    Virtual Avebury: Exploring sense of place in a virtual archaeology simulation

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    This paper describes and discusses creating and evaluating a virtual reality simulation of Avebury Stone Circle and Henge complex as it might have appeared and sounded circa 2300 BCE. Avebury is a Neolithic heritage site in the UK which is part of the Stonehenge, Avebury and Associated Sites UNESCO World Heritage Site. The overall aim of the project was to better understand the sense of place and presence that visitors can experience in virtual simulations of heritage sites. We investigated how virtual spaces might become experienced as places by visitors through their exploration, active participation, sensory stimulation and communication with other visitors in the simulation. More than 1200 members of the public experienced the simulation, both at Avebury itself and at three public exhibitions. The specific objectives of the project were to explore if and how the believability of a simulation was associated with feeling a sense of place in the virtual landscape, and if some personal characteristics, viz. age, disability, sex, immersive tendency, familiarity with IT and frequency of playing computer games, were associated with levels of enjoyment in, and learning from, the simulation. We analysed the data from a detailed questionnaire completed by 388 of the 702 visitors to Avebury from June to September 2018 who experienced the simulation, supported by observational data from all participants at all events. We found that believability was associated with a sense of place in the simulation, i.e. that the more believable the simulation appeared, the greater the sense of place experienced by the participants. We also found that personal characteristics had very little influence upon visitor reactions to the simulation, suggesting that such simulations might have wide appeal for heritage and museum visitors, regardless of age, gender or familiarity with technology

    Tolerance of septoria leaf blotch in winter wheat

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    For individual varieties, tolerance of septoria leaf blotch was quantified by the slope of the relationship between disease and yield. Variation in disease severity and the associated yield responses were provided across two sites and three seasons of field experiments. Slopes were fitted by residual maximum likelihood for two contrasting models: (i) a fixed-effects model, where no prior assumptions were made about the form of the variety slopes; and (ii) a random-effects model, where deviations in individual variety slopes away from the mean variety slope formed a normal random population with unknown variance. The analyses gave broadly similar results, but with some significant differences. The random model was considered more reliable for predicting variety performance. The effects of disease were quantified as symptom area and green canopy duration. Models of the relationship between symptom area and yield were site-specific. When site effects were not taken into account, these models had poor predictive precision. Models based on the canopy green area gave robust predictions of yield and were not site-specific. Differences in disease tolerance were detected in a comparison of 25 commercial winter wheat varieties. Tolerance was not detected directly through symptom measurements, but instead through measurements of canopy green area, which provides a measurement of the effects of disease that accounts for differences in canopy size across sites and seasons. The varieties showing greatest tolerance tended to have lower attainable yield than the intolerant varieties. Presence of the 1BL/1RS chromosome translocation, which has been reported to increase radiation use efficiency, appeared to be associated with intolerance

    Effects of environmental factors on development of Pyrenopeziza brassicae (light leaf spot) apothecia on oilseed rape debris

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    Publication no. P-2001-0221-01R. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 2001The development of Pyrenopeziza brassicae (light leaf spot) apothecia was studied on petiole debris from artificially infected oilseed rape leaves incubated at temperatures from 6 to 22 degreesC under different wetness regimes and in 16 h light/8 h dark or continuous darkness. There was no significant difference between light treatments in numbers of apothecia that developed. Mature apothecia developed at temperatures from 5 to 18 degreesC but not at 22 degreesC. The rate of apothecial development decreased as temperature decreased from 18 to 5 degreesC; mature apothecia were first observed after 5 days at 18 degreesC and after 15 days at 6 degreesC. Models were fitted to estimates of the time (days) for 50% of the maximum number of apothecia to develop (t(1); model 1, t(1) = 7.6 + 55.8(0.839)(T)) and the time for 50% of the maximum number of apothecia to decay (t(2); model 2, t(2) = 24.2 + 387(0.730)(T)) at temperatures (T) from 6 to 18 degreesC. An interruption in wetness of the petiole debris for 4 days after 4, 7, or 10 days of wetness delayed the time to observation of the first mature apothecia for approximate to4 days and decreased the number of apothecia produced (by comparison with continuous wetness). A relationship was found between water content of pod debris and electrical resistance measured by a debris-wetness sensor. The differences between values of tl predicted by model 1 and observed values of t(1) were 1 to 9 days. Model 2 did not predict t(2); apothecia decayed more quickly under natural conditions than predicted by model 2.Peer reviewe

    Meteorological and landscape influences on pollen beetle immigration into oilseed rape crops

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    Heavy reliance on pesticide inputs to maintain crop yields has been an important aspect of agricultural intensification. Insecticide use has had detrimental impacts on pollinators and natural pest control agents, contributing to a decline in associated ecosystem services, and has also led to resistance development in pest populations. Throughout Europe, in oilseed rape (Brassica napus L.) crops, prophylactic use of insecticides against pollen beetles (Meligethes aeneus F. also known as Brassicogethes aeneus) has led to such issues, and there is an urgent need to develop more sustainable pest management practices for the crop. Although advice is available to oilseed rape growers regarding control thresholds, it may not be adhered to due to the expense of pollen beetle monitoring relative to the inexpensive cost of pyrethroid insecticides. Thus, the key to reducing prophylactic insecticide applications may lie with improved, less labour intensive methods of pollen beetle monitoring. For these to be realized, a better understanding is needed of the effects of agri-landscape features and meteorological conditions on pollen beetle immigration into the crop. In this study, based on data from four years of pollen beetle monitoring on a total of 41 field sites, we model the effects of meteorological (wind speed and direction, rainfall and accumulated temperature) and landscape (areas of woodland, residential gardens, the current and previous seasons’ oilseed rape crops, and lengths of hedgerows and treelines) variables on directional sticky trap catches, at both the single trap and field scales. Meteorological variables, particularly accumulated temperature and wind speed were more important than landscape variables in predicting the abundance of pollen beetles immigrating into OSR fields. Sticky traps that were facing downwind caught more beetles than those that were facing across-wind or upwind; this is the first study to show at a landscape-scale, direct evidence for use of upwind anemotaxis by pollen beetles at the point of entry during immigration into the crop. At the field scale, the area of oilseed rape grown in the previous season was found to be positively related to trap catch, but no relationships with other landscape variables were found. Optimally-placed monitoring traps could complement existing decision support systems to reduce pollen beetle monitoring effort and encourage use of insecticides only when control thresholds are breached, thus enhancing the sustainability of oilseed rape production. Knowledge of the area of oilseed rape crops grown during the previous season in the surrounding landscape could contribute to risk assessment of potential pest pressure for individual OSR crops

    Cross-Sample Validation Provides Enhanced Proteome Coverage in Rat Vocal Fold Mucosa

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    The vocal fold mucosa is a biomechanically unique tissue comprised of a densely cellular epithelium, superficial to an extracellular matrix (ECM)-rich lamina propria. Such ECM-rich tissues are challenging to analyze using proteomic assays, primarily due to extensive crosslinking and glycosylation of the majority of high Mr ECM proteins. In this study, we implemented an LC-MS/MS-based strategy to characterize the rat vocal fold mucosa proteome. Our sample preparation protocol successfully solubilized both proteins and certain high Mr glycoconjugates and resulted in the identification of hundreds of mucosal proteins. A straightforward approach to the treatment of protein identifications attributed to single peptide hits allowed the retention of potentially important low abundance identifications (validated by a cross-sample match and de novo interpretation of relevant spectra) while still eliminating potentially spurious identifications (global single peptide hits with no cross-sample match). The resulting vocal fold mucosa proteome was characterized by a wide range of cellular and extracellular proteins spanning 12 functional categories
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