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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

Chemical composition and transport of ambient aerosols

Chung, Meng-Chen January 2000 (has links)
No description available.
2

Atmospheric Water Harvesting by an Anhydrate Salt and Its Release by a Photothermal Process Towards Sustainable Potable Water Production in Arid Regions

Alsaedi, Mossab K. 11 1900 (has links)
Only 2.5% of the water on Earth is fresh water and only less than 1% is accessible to human consumption. Landlocked and desert communities and communities that are not wealthy enough to provide clean drinking water via conventional water treatment technologies are facing severe water shortages and tend to rely on long distance transportation to supply fresh water for their daily use. As a lot of the water-scarce countries have abundant annual solar irradiation and relatively high humidity, this project proposes a technology that harvests water from ambient air using an anhydrate salt and releases it for collection using sunlight. This technology is designed to be potentially deployed in night-day cycles, as the humidity at night is at its peak, and solar irradiation during the day is also at its peak. In this work, a mesoporous silica powder filled with CuCl2 and coated with carbon nanotubes is used. The water capture performance of this material was investigated with different relative humidity environments. Furthermore, the powder agglomeration sizes of this material were also investigated for each relative humidity environment. Water release was investigated under 1 kW/m2 simulated solar light in an in-lab ~60% relative humidity environment. The results show that this mesoporous material was able to capture water at 12% relative humidity conditions, low enough to capture water from the air in the Sahara Desert. At relative humidity of 15% and 35%, the material was able to absorb 0.12 and 0.25 kg/kg of water, respectively, within 100 minutes, which indicates its fast water harvesting kinetics. A fully hydrated sample released 0.26 kg/kg of water in almost half an hour under 1 kW/m2 simulated sunlight. This project sheds more light on utilizing the atmosphere as an alternative water source.
3

Measuring the ranking capability of SWA system

Shurrab, O., Awan, Irfan U. January 2015 (has links)
No / The analysts need timely and accurate information to conduct proactive action over complex situations. Typically, there are thousands of reported activities in real time operation, although, to direct the analysts attentions to the most important one, researchers have designed multiple levels of situational awareness (SWA). Each process lends itself to ranking the most important activities into a predetermined order. According to our best knowledge, less attention has been given to the performance evaluation with regards to the prioritisation stage. Specifically, the performance metric, "The Activity of Interest Scores" has not considered corner cases of different situational assessments needs and configurations. Originally, it had not been designed for measuring the capability of the SWA system. In this paper, we have proposed a new performance metric, as well as a guidance case study for measuring the ranking capability of SWA systems. Our initial result shows that, The Ranking Capability Score has provided an appropriate scoring scheme for different ranking capabilities of SWA systems.
4

ION-MOLECULE REACTIONS STUDIED BY USING DENSITY FUNCTIONAL THEORY CALCULATIONS AND MASS SPECTROMETRY FOR SATURATED HYDROCARBON ANALYSIS AND THE STUDY OF ORTHO- AND PARA-PYRIDYNES

Jacob R Milton (11190201) 27 July 2021 (has links)
The work described herein is related to gas-phase ion-molecule reactions studied by using mass spectrometry. Chapter 2 describes density functional theory, a method used in chapters 4 and 5 to propose reaction mechanisms for reactions previously observed by others by using mass spectrometry. Chapter 3 describes a study that demonstrates that the fragmentation of saturated hydrocarbons occurs due to proton-transfer reactions that occur between these species and protonated molecules generated from molecules present in air such as nitrogen and water. Saturated hydrocarbons are studied in a wide variety of fields, and better methods to analyze complex mixtures of these compounds would facilitate their analysis. Chapter 4 discusses mechanisms of reactions for previously studied ion-molecule reactions of pyridynes studied by others by using mass spectrometry. Reactions of pyridynes are important to study arynes have been previously used in organic synthesis, and pyridine moieties are particularly common in biological compounds. Chapter 5 discusses density functional theory calculations used to determine why some organic polyradical undergo hydride abstractions from cyclohexane while others do not. The study discusses reactions taking place between both singlet and triplets states of the 2,5-didehydropyridinium cation and cyclohexane as a model, which are compared to reactions of the 2-pyridyl cation and 2-dehydropyridinium cation with cyclohexane. These studies may help improve our understanding of the reactivity-controlling factors of organic polyradicals, which may help improve toxic drug candidates like cytostatic enediynes.

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