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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

Liquid Nitrate Fertilizer Production with Various Atmospheric Pressure Discharges

Zhenyu Shen (6630833) 11 June 2019 (has links)
<div>Plasmas can be used to increase the probability of maturity of seeds and disinfect them. The water applied on plants can also be treated with plasma to reduce bacteria. Discharges normally used to treat water including dielectric barrier discharges, gliding arcs, DC, AC, or pulsed coronas, and various direct discharges in liquid. After treatments, reactive oxygen (ozone) and nitrogen species (nitrite and nitrate) will appear in the water solution. Then, by applied this water, the lifecycle of plant could be significantly influenced. Plasma has a great potential to play an important role in the agriculture discipline. The process of synthesizing nitrate fertilizer with water, air, and electric spark has been known for a long time. But due to low nitrate yield and high energy consumption, it was replaced by the Haber-Bosch process in the first half of the 20th century. The Haber-Bosch process, however, has several disadvantages: it requires natural gas as a raw material, fixes nitrogen in the form of ammonia, and generates oxycarbides as byproducts. Thus, the concept of manufacturing nitrogen fertilizer with only water, air and electricity is still appealing.</div><div><br></div><div>In this project, we want to measure the pH value and conductivity of the water treated by various atmospheric pressure discharges including the arc discharge, DC positive corona discharge, DC voltage driven cold plasma torch operating with helium, dielectric barrier discharge (DBD), and radio-frequency (RF) plasma. Also, it is necessary to verify the existence of different important species in the treated water such as peroxide, nitrite, and nitrate ions by measuring their concentrations. Based on current and voltage measurements and wall-plug electrical energy consumption, energy efficiency of nitrate synthesis was determined in these five plasma systems. Optical emission spectroscopy was employed to study the reaction kinetics of both DBD and RF discharge. Our goal is to produce enough nitrate ions, by plasma treatment with minimal energy input (the value should be at least close to the Haber-Bosch process), in water which could be further used as fertilizers.</div><div><br></div>
2

Evaluation Strategies for Risk Assessment and Usability of Medical Plasma Sources in Dermatology

Tiede, Regina 04 August 2017 (has links)
No description available.

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