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Atmospheric histories and global emissions of the anthropogenic hydrofluorocarbons HFC-365mfc, HFC-245fa, HFC-227ea, and HFC-236fa

We report on ground-based atmospheric measurements and emission estimates of the four anthropogenic hydrofluorocarbons (HFCs) HFC-365mfc (CH 3CF2CH2CF3, 1,1,1,3,3- pentafluorobutane), HFC-245fa (CHF2CH2CF3, 1,1,1,3,3-pentafluoropropane), HFC-227ea (CF3CHFCF3, 1,1,1,2,3,3,3-heptafluoropropane), and HFC-236fa (CF3CH 2CF3, 1,1,1,3,3,3-hexafluoropropane). In situ measurements are from the global monit

Global emissions of HFC-143a (CH3CF3) and HFC-32 (CH2F2) from in situ and air archive atmospheric observations

High-frequency, in situ observations from the Advanced Global Atmospheric Gases Experiment (AGAGE), for the period 2003 to 2012, combined with archive flask measurements dating back to 1977, have been used to capture the rapid growth of HFC-143a (CH3CF3) and HFC- 32 (CH2F2) mole fractions and emissions into the atmosphere. Here we report the first in situ global measurements of these two gases. HF

Metalliferous sediments from the H.M.S. Challenger voyage (1872-1876)

The legendary cruise of H.M.S. Challenger (1872-1876) around the globe must always occupy an eminent place in the annals of oceanography, as being the first systematic attempt made on a global scale to explore the ocean. This expedition made fundamental discoveries in biology and geology which have not been surpassed by any later scientific cruise. Sediment with high content of metals (later calle

Measurement of zinc stable isotope ratios in biogeochemical matrices by double-spike MC-ICPMS and determination of the isotope ratio pool available for plants from soil

Analysis of naturally occurring isotopic variations is a promising tool for investigating Zn transport and cycling in geological and biological settings. Here, we present the recently installed double-spike (DS) technique at the MAGIC laboratories at Imperial College London. The procedure improves on previous published DS methods in terms of ease of measurement and precisions obtained. The analyti

Evidence for the mechanisms of zinc uptake by rice using isotope fractionation

In an earlier study, we found that rice (Oryza sativa) grown in nutrient solution well-supplied with Zn preferentially took up light 64Zn over 66Zn, probably as a result of kinetic fractionation in membrane transport processes. Here, we measure isotope fractionation by rice in a submerged Zn-deficient soil with and without Zn fertilizer. We grew the same genotype as in the nutrient solution study

Accurate and precise zinc isotope ratio measurements in urban aerosols

We developed an analytical method and constrained procedural boundary conditions that enable accurate and precise Zn isotope ratio measurements in urban aerosols. We also demonstrate the potential of this new isotope system for air pollutant source tracing. The procedural blank is around 5 ng and significantly lower than published methods due to a tailored ion chromatographic separation. Accurate

Atmospheric deposition and isotope biogeochemistry of zinc in ombrotrophic peat

Zinc isotope ratios were measured in the top sections of dated ombrotrophic peat cores in Finland to investigate their potential as proxies for atmospheric sources and to constrain post depositional processes affecting the geochemical record. The peat deposits were located in Hietajärvi, a background site well away from any point pollution source and representing 'background' conditions, in Outoku

An experimental and theoretical investigation into the use of H2 for the simultaneous removal of ArO+ and ArOH+ isobaric interferences during Fe isotope ratio analysis with collision cell based Multi-Collector Inductively Coupled Plasma Mass Spectrometry

Hydrogen in a hexapole collision cell is used with varying success in multi-collector Inductively Coupled Plasma Mass Spectrometry to reduce the plasma derived interferences 40Ar16O+ and 40Ar16OH+ that are isobaric with 56Fe+ and 57Fe+ respectively. The reactions of ArO+ and ArOH+ with H2 in the hexapole of a multi-collector Inductively Coupled Plasma Mass Spectrometer were studied practically and

Developing and testing a PM2.5 low-cost sensor in Ethiopia under ambient and indoor air pollution conditions

PM2.5 low-cost sensors are a promising trend for low-income countries, where the PM2.5 associated burden of disease is high and few measurement instruments are available. Commercially available Sensor Systems (SSys) are relatively affordable and easy to use. They are, however, not designed for or evaluated in contexts characterized by much biomass burning, regular power interruptions and/or low in

Using student science to identify research priority areas for air pollution in a university environment : an Ethiopian case study

Students in a country like Ethiopia face a double air pollution challenge: they are frequently exposed (both outdoors and indoors) to sources of incomplete combustion and therefore to unhealthy concentrations of particulate matter (PM2.5) and carbon monoxide (CO), while they also face increased carbon dioxide (CO2) concentrations in crowded dormitories and classrooms. Research on air pollution in

Roadside PM2.5 concentrations measured with low-cost sensors and student science in Arba Minch, Ethiopia

Exposure to PM2.5 poses one of the biggest health threats, with traffic and biomass burning as dominant sources in urban areas of low-income countries. In Ethiopia, the combination of these two sources suggests a high roadside exposure. Because of a lack of resources for data collection, only few studies were conducted on roadside exposure in Ethiopia. Using low-cost sensors and student science co

An evaluation of best practices in an air quality student science project in Ethiopia

A science project as part of a student’s curriculum, which we call student science, might be the answer to two problems for a low-income country like Ethiopia: conventional science can be expensive and many students lack training in practical skills. Earlier studies have been conducted with respect to lay people (citizens or students) conducting (parts of) research (e.g. citizen science), but rare

Historia och nationalism : Sverigedemokraternas och Dansk Folkepartis historiska berättelser

This thesis studies the relationship between history and nationalism as expressed by the political parties the Sweden Democrats and the Danish People's Party. The study focuses on how the Sweden Democrats and the Danish People's Party convey historical narratives in their party magazines, SD-Kuriren and Dansk Folkeblad, respectively, and in central party documents. The narrative theory being imple

Political uses of the Viking Age : The Sweden Democrats and the Danish People’s Party

This chapter explores how the two contemporary political parties, the Sweden Democrats and the Danish People’s Party, use the Vikings and the Viking Age as symbols in their national mythmaking. It examines the political dimensions of public history and the way in which these parties draw historical parallels between the Viking Age and the present in order to call for action. The relationship betweThis chapter explores how the two contemporary political parties, the Sweden Democrats and the Danish People’s Party, use the Vikings and the Viking Age as symbols in their national mythmaking. It examines the political dimensions of public history and the way in which these parties draw historical parallels between the Viking Age and the present in order to call for action. The relationship betwe