3,006 research outputs found
L to R: Vern Nichol, Rowland Walker, A.L. Hamlin, and Jack Walker at Ecker Hill, circa 1933.
No full textPhoto shows four early Utah ski jumpers: L to R: Vern Nichol, Rowland Walker, A.L. Hamlin, and Jack Walker at Ecker Hill, circa 193
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Letter from A.L. Monmerqué de Courmont.
No full textLetter from A.L. Monmerqué de Courmont, possibly Adélaïde Louise de Monmerqué (1767-1835) who had been married to Louis Marie Le Bas de Courmont (1741-1794), dated 10 pluvoise. It is not addressed but was presumably sent to Philippe-Antoine Merlin, as it comprises the verso of one of his requisitions from 1802. In this letter the author requests a day and an hour when she (or he) might meet with the recipient
L to R: Dave Quinney Sr., Vern Nichol, Rowland Walker, A.L. Hamlin, Jack Walker, Alf Engen, Bill Bailey, Charles Wanless, and unidentified at Ecker Hill, circa 1933.
No full textPhoto of the Mount Olympus Ski Club jumpers, L to R: Dave Quinney Sr., Vern Nichol, Rowland Walker, A.L. Hamlin, Jack Walker, Alf Engen, Bill Bailey, Charles Wanless, and unidentified at Ecker Hill, circa 193
Mount Olympus Ski Club jumpers, L to R: Dave Quinney Sr., Vern Nichol, Rowland Walker, A.L. Hamlin, Jack Walker, Alf Engen, Bill Bailey, Charles Wanless, and unidentified at Ecker Hill, circa 1933.
No full textPhoto of the Mount Olympus Ski Club jumpers, L to R: Dave Quinney Sr., Vern Nichol, Rowland Walker, A.L. Hamlin, Jack Walker, Alf Engen, Bill Bailey, Charles Wanless, and unidentified at Ecker Hill, circa 193
Depositional environment of the snow cover on West Antarctic pack-ice floes
No full textThe depth, density, load and isotopic (δ18O) composition of the snow cover on pack-ice floes were measured in late austral summer 1992 in the eastern Ross, Amundsen and western Bellingshausen Seas. Snow-density values commonly exceeded 350 kg m-3 and some were as high as 500 kg m-3. The densification of the snow occurs quickly and is attributed to a windy environment. The high density and sometimes considerable depth of the snow on the floes accounts for loads of as much as 700 kg m-2 and resultant sea-water flooding of the underlying sea ice. Lower mean δ18O values in the Ross/Amundsen Seas snow cover suggest that the region might have a cooler climate than the Bellingshausen Sea region. Snow depths on floes in the Bellingshausen Sea region were lower than those in the Ross/Amundsen Seas region, because the Bellingshausen Sea floes were first-year ice. Possible annual units in the isotope profiles of snow, as much as 2m deep, indicate that floes in the Ross/Amundsen Seas region were 2-3 years old.</jats:p
METODOLOGIE GEOCHIMICHE DI ANALISIDEL PARTICOLATO SOLIDO AERODISPERSOE VALUTAZIONE DEI CONTRIBUTI ANTROPICI E NATURALI
No full textThe particulate matter is a complex mixture of liquid and solid particles in a suspension. The chemical composition of the particles can be very different depending on the emission sources: anthropogenic (combustion, industrial emissions…) or natural (sea spray, soil re-suspension, biogenic aerosol, forest fires, volcanic ashes, Saharan dust).
Different studies have showed that the anthropogenic particulate are formed as a result of low quality of the air, but is important the natural particulate too. Such emissions do not create big pollution problems, because they occur on a small temporal scale. Some particular cases have formerly reported in this regard; for instance, the Saint Helens volcano, erupted in May 1980, caused a worsening in the quality of the air in the United States and in all north-west Pacific Sea, or in another case, the Tambora volcano in Indonesia erupted in April 1815 with an emission of ashes one hundred times greater than the Saint Helens eruption, causing death and famine and a reduction of the solar radiation, which let to very cold winter. The Saharan dust can travel in the air for thousands of miles coming until Italy, Greece or United Kingdom. Therefore, it is important to study the natural and anthropogenic emissions of the particulate matter to reduce the concentrations of aerosol in atmosphere and to protect the human health [Pope, 2000a e b; Harrison, et al., 2004]. The United Nations Economic Commission for Europe (UNECE) showed how important is to define the local and transboundary background levels to reduce the emissions.
The aim of this thesis was to adopt a methodology to analysis the particulate matter according to the measures provided in Directive 2008/50/CE [Directive 2008/50/CE, EU Parliament], which explains the necessity of reducing the air pollution to protect ambient and human health with good monitoring and valuation of the quality of the air [UE n. 1600/2002/CE, 22 July 2002]. The researchers of ENEA developed a data processing in order to estimate the importance of some natural sources of emissions in the increasing of the particulate matter, through MINNI project (Modello Integrato Nazionale a supporto della Negoziazione Internazionale sui temi dell’Inquinamento Atmosferico - National Integrated Model to support the international negotiation on atmospheric pollution). The main target of this thesis is to develop an analytical methodology to analyze the chemical composition of the aerosol emitted from different sources in different area in Italy. To do so, different samples of aerosols were obtained on filters and their chemical composition was determined by ICP-MS. The sample preparation for ICP-MS analysis involved the extraction of the inorganic ions in a water solution with ultrasonic [EMEP, 1996]. However, some problems were created with this methodology; for example, the loss of the samples on the filter. For this reason, the sample preparation for ICP-MS involved the dissolution of both the aerosol and the filter. The new analysis protocol was taken place as follows: a low quantity of reagent was used and ensured the complete dissolution of the filter and the aerosol in an acid solution on a hotplate. The acid solutions of HF, HNO3 e H2O2 were used through different steps. The quartz filters showed the best results for ICP-MS analysis, because they provide a low background value during the analysis. Different typologies were also tested: Whatman, Pallflex and SKC. Pallflex® and SKC, however, showed the best results for acid dissolution. On the other side, Teflon filters showed the best results for SEM-EDS analysis, because they allow the collection of an accurate particle size of the aerosol, and they are not made of silica. This is important because they allow to determine the silica particles.
Various monitoring and sampling approaches were carried out in different areas of Italy, during 2009 and 2010, to identify the natural contribution of the aerosol in atmosphere.
The first approach was tested as part of the MINNI project “determination of PM10 and PM2,5 mass due to natural sources (Saharan dust, sea spray and wind re-suspension of crustal material) and temporary anthropogenic activity (construction sites and agricultural operations)” with ENEA collaboration. The aim of this project was to evaluate the increase of PM in atmosphere during agricultural activity. The sampling area is located in the Po Valley, near Adriatic Sea. It is an area with an elevate concentration of aerosol and with a lot of agricultural area, without farms or industries in a ratio of 30 km Sampling was carried out in 2009, during the main activity of the wheat cycle: wheat threshing (June 2009), plowing (October 2009) and wheat sowing (November 2009). The aerosol emitted during these three agricultural operations was gathered on filters through Marple Impactor. These filters were analyzed by ICP-MS to know the chemical composition of the aerosol and by SEM-EDS to know the morphology of the particles. The comparison of these two methodologies has allowed determining the markers of the natural sources of the particulate matter. The results showed a low contribution of the aerosol emitted from these agricultural operations, because the particles had large size and they fall down rapidly on the ground. The imaging by SEM-EDS showed high amount of organic materials (pollen, spores, molds and bacteria) on the filters in all agricultural activity, which can create serious problem on human health, because their size is very small (less than 2.5 μm). This could be very important for epidemiological studies, especially in people who work with soil.
Within the MINNI project, the concentrations of particulate matter analyzed in an area in the south of Italy (Trisaia – Matera), to evaluate the levels of background and the anomalies of PM concentrations during Saharan events and sea spray contributions. Trisaia was chosen as a test site because it is an area near the sea and subjects to Saharan dust in the summer, and also there is no industrial district in the region. For this reasons, it could be a perfect site to analyze the natural contribution of particulate matter. The sampling and analysis methodologies were defined during the 2009, and in the summer 2010 (May and June). Sampling was carried out in Trisaia, which is 4 Km far from the sea and on the border between Basilicata and Calabria. The aerosol was sampled on filters through Andersen Impactor for PM10 and PM2,5 in a time of 23 hours and 30 minutes for all days of the sampling. These filters were analyzed by ICP-MS to know the chemical composition of the aerosol. Moreover, SEM-EDS was performed to know the morphology of the particles. The ICP-MS data showed a negligible presence of pollutants that validate a low anthropogenic contribution and confirmed that the test site is a good site to study the particulate from natural sources. The SEM imaging showed that the major contribution of the aerosol was due to crustal material and sea salt in the fine fraction and in the coarse fraction. In June, the concentrations of PM were higher than in May, because of the Saharan dust event (11 – 19 June 2010). The contribution of sea spray is evident through the high presence of Sodium and salt hydrates. The ICP-MS and SEM results showed a considerable concentration of carbonate by re-suspension of lithologies from the mountains near the test site. The conclusion of this study is that the contribution of sea salt is high in areas near the sea, which can influence the increase of aerosol in atmosphere. Also, the Saharan dust contributes at increasing the aerosol in atmosphere especially in areas in the south of Italy, exceeding the limits allowed by law.
Po Valley and Friuli Plain in Italy and Belgian Plain in Europe, are areas with the highest concentration of solid particulate matter in all the world [European Space Agency, 2004]. This implies that those areas do not follow the limits imposed by European Parliament in 2008 [EU Parliament legislative, 2007; EU Parliament directive, 2007]. Aim of this study is the characterization of the particulate matter through direct sampling in atmosphere to define physical properties and source of this particulate. A first campaign was carried out in June-July 2009 in the Po Valley during farming activities of threshing. A second campaign has been carried out in June-September 2009 in the city of Trieste during activity and no activity of the Servola iron foundry. In both campaigns, the aerosol was collected by means of a small aircraft (Cessna 172P), in collaboration with OGS (l’Istituto Nazionale di Oceanografia e Geofisica Sperimentale - Trieste). Particle concentration was measured for five particle sizes (0.5, 1.0, 2.5, 5.0, 10.0 microns) using a laser counter (LIGHTHOUSE HH 3016). The acquisition has been carried out vertically profiling the atmosphere from 150 to 2400 meters. SEM, as well as SEM-XPD analysis on single particles, was carried out with the aim to obtain detailed dimensional and morphological information to define origin, toxicity and the nature of organic matter. An impactor was located in the ram air intake. The collection of the particles was conducted using the direct flux of air. It was assumed that the speed of the aircraft has been maintained steady, this causes the entrance of the ram air in the filter at a constant flow, so it is possible to know the quantity of air passing through Teflon filter. This was possible in the Po Valley, because there is no mountain, but it was impossible in Trieste, because the presence of mountains and of updrafts not allow to maintain a constant velocity. SEM-EDS analysis of the samples of Po Valley showed the presence of particles that are not influenced by agricultural activity. This confirms that the threshing operation not influenced the increase of PM in atmosphere. Instead, in the samples of Trieste SEM-EDS analysis showed a high contribution of carbonate particles, originated from the erosion of the carbonate quarry near the sampling site. The analysis showed also carbon particles, but in a percentage negligible. Despite this, the data showed that the percentage of carbon particles in June is higher than in September, probably the Servola iron foundry is not the only anthropogenic source that increases the carbon concentration in atmosphere. It is important to consider the high impact of the harbor pollution, because there is a big industrial harbor near the city of Trieste.
In a last project, the concentration of particulate matter in atmosphere was analyzed by sampling the snow in different period of the winter 2009-2010. The analytical methodologies were defined to characterize the morphological and chemical composition of the particles inside the snow and discriminate the local and transboundary contributions. In literature, a few studies analyzed the aerosol less than 2,5 μm, because it is difficult to sample and analyze aerosols with this size [Brunekreef, et al., 2002]. The snow were analyzed and collected in Ferrara and in Dolomite. It is noted that extreme conditions of snowfall can remove the particulate in atmosphere and create good conditions to collect this pollutant [Loranger, et al., 1996] and hypothesize its source, transport and deposition [Barrie & Vet, 1984; Hautala, et al., 1995]. Chemical analysis might be a good way to know the contamination level in urban area. Despite this, the identification of the sources is difficult, especially for the trace elements that are present both in anthropogenic and natural event. Sample the snowfall was important to understand if it might be considered an indicator to evaluate the anthropogenic impact and/or transboundary of particulate matter. The samples were collected in urban and rural area in Ferrara (Po Valley) and in the Dolomite, and they were analyzed by SEM, IC and ICP-MS. Thanks to this project, the sampling of snow samples allowed to characterize alkaline elements and the particulate matter. This is important, because the soluble particles can interact with biomass and penetrate in groundwater, creating serious environmental problems. Also, the snow melts on the leaves or on the trees and the particulate can be re-suspended creating serious problem on human health. SEM analysis, in collaboration with Birmingham University Department of Geography Earth & Environmental Sciences, showed that the particles are characterized by silica, carbonate, carbon and organic material. Also, ICP-MS data showed high concentration of alkaline elements only in the samples collected near streets (anthropogenic contribution). Chemical and morphological analysis allowed us to know the contamination of the air in urban areas. Despite this, the identification of the particulate matter is not easy, especially for trace elements that are present both in anthropogenic and natural events. This study suggests that there is a direct contamination of the snow from anthropogenic sources (road traffic) and so an important concentration of trace elements near the streets with large number of vehicles passing nearby. The results showed that the snow is interesting to understand the critical level, the contribution of the different sources and the risks for human health and the environmental
Policy implications of warming permafrost
No full textPermafrost is perennially frozen ground occurring in about 24% of the exposed land surface in the Northern Hemisphere. The distribution of permafrost is controlled by air temperature and, to a lesser extent, by snow depth, vegetation, orientation to the sun and soil properties. Any location with annual average air temperatures below freezing can potentially form permafrost.
Snow is an effective insulator and modulates the effect of air temperature, resulting in permafrost temperatures up to 6°C higher than the local mean annual air temperature. Most of the current permafrost formed during or since the last ice age and can extend down to depths of more than 700 meters in parts of northern Siberia and Canada. Permafrost includes the contents of the ground before it was frozen, such as bedrock, gravel, silt and organic material. Permafrost often contains large lenses, layers and wedges of pure ice that grow over many years as a result of annual freezing and thawing of the surface soil laye
Численное моделирование осаждения снега вблизи снегозадерживающих заборов
No full textThe results of numerical modeling of the influence of geometric characteristics of snow-protecting fences on the intensity of snow deposition at the initial stage of formation, that is, without taking into account the influence of the dynamics of the shape of the snow cover surface, are presented. In the most industrialized and densely populated region on the Arctic Krasnoyarsk Territory - the industrial City of Norilsk, daily snowfall can exceed 50 mm, the snow depth reaches, on the average, 47 cm (the largest is 70 cm), while the wind speed - 25-30 m/s. This promotes formation of snow deposition on roads, in residential areas as well as in industrial sites and infrastructure facilities, which hampers and sometimes completely stops operation of them. As part of the solution of these problems, a software package has been developed aimed at numerical modeling of snow transport processes and implementing the snow protection measures. To simulate the dynamics of the windinduced snow drift, a microscale model of the atmospheric boundary layer was used together with a diffusion-inertial description of the transport of the snow dispersed phase. Analysis of the calculation results shows that the width of the plates, as well as their spatial orientation, have insignificant effect on the snow-holding capacity of fences. The size of the gaps between the rails and the height of the lower gap exerts the greatest influence on the distribution of the intensity of snow deposition, both on the leeward and windward sides of the fence. In general, we can talk about the relationship between the wind speed field formed during the drift around the fence and the distribution of the snow deposition intensity. Thus, a relative decrease in the average wind speed from the leeward side of the fence increases the precipitation intensity. The presented results of numerical modeling do not contradict data of field observations previously obtained by other authors, and, thus, the developed software package allows comparing effectiveness of different snow-protecting constructions.Описывается математическая модель переноса снега ветром, реализованная в программном инструменте, предназначенном для разработки снегозащитных мероприятий. С его помощью проведено численное исследование влияния геометрических параметров снегозащитных заборов на интенсивность осаждения снега вблизи них. Показано, что наибольшее влияние оказывают просветность и высота нижнего зазора забора
Seasonal variation in marine-snow-associated and ambient-water prokaryotic communities in the northern Adriatic Sea
No full textThe structure and activity of prokaryotic communities were determined in marine snow and in the ambient water of the northern Adriatic Sea in different seasons (autumn, spring and summer). The seasonal variation in the composition of marine-snow-associated and ambient-water bacterial communities was assessed by T-RFLP (Terminal Restriction Fragment Length Polymorphism) on the 16S rRNA gene (16S rDNA) and 16S rRNA transcript (16S rRNA) level. On the 16S rDNA level, the bacterial community composition of the marine snow and ambient water was similar in summer and autumn, but not in spring. In contrast, on the 16S rRNA level, indicative of the active bacterial community, the marine-snow-associated bacterial community was different from that of the ambient-water, and different from the bacterial community on the 16S rDNA level, except in autumn. To phylogenetically characterize the bacterial and archaeal community composition associated with marine snow and the ambient water, clone libraries of 16S rDNA and 16S rRNA were constructed from 2 contrasting seasons. Phylogenetic profiling revealed a higher similarity among bacterial communities in summer compared to late autumn. Certain bacterial and archaeal groups were exclusively associated with summer or autumn marine snow, suggesting that marine-snow-associated prokaryotic communities are subjected to successional changes similar to ambient-water communities. Moreover, the presence of bacterial groups enriched in marine snow including Vibrionales and sulphate-reducing bacteria is consistent with niche partitioning and metabolic adaptations of the particle-associated microbiota
S.L.I.M., a small linear interdependent model of eight EU-member states, the USA and Japan
No full textInternational Economics;EU
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