Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Institution
Articles 1 - 6 of 6
Full-Text Articles in Engineering
Theoretical Investigations Of The Electronic, Magnetic, And Thermoelectric Properties Of Transition-Metal Based Compounds, Haleoot Edaan Raad
Theoretical Investigations Of The Electronic, Magnetic, And Thermoelectric Properties Of Transition-Metal Based Compounds, Haleoot Edaan Raad
Graduate Theses and Dissertations
The electronic, magnetic, and thermoelectric properties of transition-metal based compounds were investigated by using the density functional theory and Boltzmann transport formalism. It was found that the Co-based Heusler compounds and InSe monochalcogenide are among the materials that may be used for future thermoelectric devices. Furthermore, the investigation showed that the quaternary Heusler compounds, such as, CoFeYGe, where Y is Ti or Cr, are half-metallic ferromagnetic materials with full electron spin polarization. The lattice thermal conductivity (κL) was found to decrease for these alloys as the temperature increases. The present investigation indicated that the phonon optical modes have a major …
Sorption Of Benzene, Toluene, Ethylbenzene And Different Ratios Of Mixture Solvent By Plasticized Pema Films Using A Qcm Sensor, Xinpeng Li
USF Tampa Graduate Theses and Dissertations
VOCs (volatile organic compounds) can cause great harm to human health especially benzene, toluene and ethylbenzene. In this work a Quartz Crystal Microbalance (QCM) sensor with a polymer/plasticizer film was developed to quantify the VOCs both in air and water. QCM is an acoustic wave sensor that can be used well in detecting the aromatic compounds in the film. Because more than one VOC is present in the air, this thesis focuses on finding the sorption of different ratios of VOCs (benzene, toluene, ethylbenzene) using a polymer/plasticizer film in QCM. Poly (ethyl methacrylate) (PEMA) was used as the polymer because …
Quantifying And Elucidating The Effect Of Co2 On The Thermodynamics, Kinetics And Charge Transport Of Aemfcs, Yiwei Zheng
Quantifying And Elucidating The Effect Of Co2 On The Thermodynamics, Kinetics And Charge Transport Of Aemfcs, Yiwei Zheng
Theses and Dissertations
Anion exchange membrane fuel cells (AEMFCs) have shown significant promise to provide clean, sustainable energy for grid and transportation applications – and at a lower theoretical cost than more established proton exchange membrane fuel cells (PEMFCs). Adding to the excitement around AEMFCs is the extremely high peak power that can now be obtained (> 3 W cm-2) and continuously improving durability (1000+ h), which has made the future deployment of AEMFCs in real-world applications a serious consideration. For some applications (e.g. automotive), the most critical remaining practical issue with AEMFCs is understanding and mitigating the effects of atmospheric CO2 (in …
Sorption Of Benzene, Tolueneand Ethylbenzeneby Plasticized Pema And Pema/Pmma Sensing Films Using Aquartz Crystal Microbalance (Qcm) At 298.15k, Deekshitha Adapa
Sorption Of Benzene, Tolueneand Ethylbenzeneby Plasticized Pema And Pema/Pmma Sensing Films Using Aquartz Crystal Microbalance (Qcm) At 298.15k, Deekshitha Adapa
USF Tampa Graduate Theses and Dissertations
Detection of volatile organic compounds (VOC’s) in the environment is important for human health and wellness. Long term exposure of certain VOC’s like benzene, toluene, ethylbenzene and xylene (BTEX) has a severe effect on human health. There are techniques such as gas chromatography, photo ionization, and mass spectroscopy that are time consuming, require gas sampling and are ineffective in real time sensing in air. Acoustic wave devices such as surface acoustic wave (SAW) devices can be used for sensing BTEX compounds in both vapor and liquid phase. The quartz crystal microbalance (QCM) is a low-frequency acoustic wave device, which can …
Energy Efficiency And Fatigue Failure On Gears And Bearings For Processing Rebar Steel, Jesus Gabriel Garcia
Energy Efficiency And Fatigue Failure On Gears And Bearings For Processing Rebar Steel, Jesus Gabriel Garcia
Open Access Theses & Dissertations
Steel industry is a major emitter of air pollutants, a leading industrial consumer of water, a minor source of contaminated liquids, a massive producer of solid waste, and a significant source of CO2. The objective on this thesis work is to minimize the greenhouse gas emissions when processing steel. Gears and bearings were evaluated based on their performance when exposed to cyclic stresses. The importance for having a proper set up on rolling mills to increase efficiency for processing rebar steel has been detailed on paper. In contrast, mechanical vibration has been measured on gears and bearings to determine efficiency …
Analytical Modeling And Life Cycle Assessment Of A Solar Powered Vapor Absorption Cooling System, Harold A. Walters
Analytical Modeling And Life Cycle Assessment Of A Solar Powered Vapor Absorption Cooling System, Harold A. Walters
Electronic Theses and Dissertations
Vapor absorption cooling systems (VACS) offer an environmentally friendly alternative to the standard vapor compression cooling systems (VCCS) for cooling homes, businesses, factories, and other buildings. VACS use low-grade thermal energy to achieve a cooling effect and require minimal electrical input for the liquid solution pump used for circulation within the system. The thermal energy which powers these systems can be provided through several means; one popular form is through the use of solar thermal collectors. This paper provides a process for determining the overall size and configuration of the VACS depending upon the operating conditions of selected components. A …