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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Emissions of organic compounds from technosphere articles : Measurements and modeling of mass transfer from consumer goods and building materials to air and water

Holmgren, Tomas January 2013 (has links)
This thesis describes the development of a generic model for predicting the emissions of organic compounds from materials used in the manufacture of various goods and products. Many products contain organic substances that are not bound to the matrix formed by their constituent materials and are thus able to dissociate from the material and become transferred into the surrounding environment. A wide range of materials and products are used in modern societies, and many compounds deriving from these materials are regarded as emerging pollutants in both indoor and outdoor environments. The model uses three components to describe the transfer of compounds from materials to the surrounding environment: partitioning of the compound between the material and its surroundings based on linear free energy relationships, diffusion within the material based on the Piringer equation, and convective mass transfer in air or water based on an empirical flat surface model. The model’s predictive capacity was tested against three experimental case studies: emissions of plasticizers from vinyl flooring and triphenyl phosphate from LCD screens into the air, and leaching of organophosphates from concrete into water. The rates of emission from vinyl flooring were clearly affected by the number of layers comprising the material. Triphenyl phosphate was found in the front surface of all tested flat screens and its rates of emission were related to the nature of the screen and its operating temperature. The model accurately predicted emissions into the air and leaching from concrete into water once modified to include modules that describe dissolution from surfaces and diffusion in water-filled pores. The model was then used to investigate emissions on the national scale. It was found that the rates of emission from vinyl flooring are not changing over time, and that the total mass of emitted material is dependent on annual sales volumes and the expected life span of the vinyl flooring. Moreover, the additive used has a large effect on the emitted mass. Emissions from flat screen displays depend strongly on their operating temperatures: displays with high working temperatures that are active for extended periods of time produce more emissions. The model was also used to study the release of organophosphates from the concrete used to make a bridge, which depended on the flow of water under the bridge, the temperature, the porosity of the concrete, and the additive’s water solubility. Data on annual sales volumes and the total surface area of sold goods are essential when studying emissions on a national scale. National retailers’ organizations are valuable sources of such information. When adequate data are not available, it is necessary to perform uncertainty analyses to determine the impact of uncertainty in the modeling of different stages of the emissions process in different scenarios.
2

俄歐能源關係之研究 / Study of Russian-European energy relation

夏明煌 Unknown Date (has links)
本文的研究目的第一是釐清能源在國際關係領域的相關議題:能源安全、能源地緣政治與對外能源政策等子議題的異同,從概念演變到局勢發展,以及個別國家的政策與成效;第二點是耙梳、彙整冷戰結束後,俄羅斯與歐洲(包括歐洲各國與歐洲聯盟)奠基於能源資源貿易關係上面一層的互賴關係,以及潛在的不穩定與衝突因素,藉由理解這個雙邊關係的發展與其未來的可能性,得以提供可能的預測與參考價值。 首先第一章是緒論,目的是解釋本文的章節架構;在第二章解釋能源安全理論與俄羅斯能源產業發展狀況;在第三章則以俄羅斯的角度看待它與前共產陣營國家之間的互動關係。第四章的主要內容則是以歐盟的角度出發,檢視歐盟與外方伙伴的互動協商過程。第五章的總結則評估雙方在能源與對外政策立場上的各自立場作為本文的結束。國家與國營能源公司是本文中最基本且主要的行為者,藉由評估他們在未來的發展方向,以及回顧過往的政策(能源政策與對外政策)成效與互動過程做為總結。 本文研究發現,鋪設能源管線、購買基礎設施的產權、以及開放油氣探勘權限等商業行為,在國家與國際組織的層級上成為地緣政治的槓桿,其結果是歐洲與歐亞大陸的能源市場整合成為一體,並在能源地緣政治上產生兩極對立體系。

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