Digital Commons Network^™

The Effect Of Mechano-Chemical Activation Of Fly Ash- Nanoparticle Blends On Performance Of Cement Based Composites And Self-Consolidating Concrete, Rani G K Pradoto

Theses and Dissertations

Other than water, portland cement concrete is the most used commodity. Major parts of civil and transportation infrastructure, including bridges, roadway pavements, dams, and buildings are made of concrete. Because of wide-scale applications of these important structures in different climatic zones and associated exposures, concrete durability is often of major concern. In 2013, the study of American Society of Civil Engineers (ASCE) estimated that one-third of America’s major roads are in poor or mediocre condition [1]. The same article reports that annual investments of $170 billion on roads and $20.5 billion for bridges are needed to substantially improve the condition …

Effect Of Pollination And Postpollination Processes On Selfing Rate, Yuliya Sorin

Theses and Dissertations

Selfing rates vary widely within and among populations of self compatible flowering plants. This variation is often attributed to differences in the amount and timing of self and outcross pollen deposition on stigmas, as well as to the influence of postpollination mechanisms that control pollen siring success. This study explores the relative importance of pollination and postpollination processes in determining selfing rates in monkeyflower, Mimulus ringens. We hand-pollinated flowers on each of 17 unrelated mothers with pollen from one of three experimental treatments intended to replicate field conditions: 1) Simultaneous deposition of 50% self pollen and 50% outcross pollen from …

Improved Attribute-Based Encryption With Fpga For Automatic Appliance Control Application In Smart Grid, Xueqing Wang

Theses and Dissertations

In this thesis, the author describes the privacy violation issues in smart grid with Automatic Appliance Control applications, and explains the security threats related to it. The smart grid is a sensitive and sophisticated system in real life operation. A mass of data including the remote control commands and users’ energy consumptions is transmitted between the utility companies and other devices in the smart grid such as the substations, smart meters, smart home appliances and much more. Without efficient cryptographic methods, an adversary may hack into the data or the remote control commands and extrapolates a resident’s activity model. Therefore, …

Nanostructured Organic/Inorganic Semicondutor Photovoltaics: Investigation On Morphology And Optoelectronics Performance, Aruna Wanninayake

Theses and Dissertations

Organic solar cell is a promising technology because of the versatility of organic materials in terms of tunability of their electrical and optical properties. In addition, their relative insensitivity to film imperfections potentially allows for very low-cost high-throughput roll-to-roll processing. However, the power conversion efficiency of organic solar cell is still limited and needs to be improved in order to be competitive with grid parity. This work is focused on the design and characterization of a new organic/inorganic hybrid device to enhance the efficiency factors of bilayer organic solar cells such as: light absorption, exciton diffusion, exciton dissociation, charge transportation …

Numerical Simulation Of Slow Drying In Porous Media Using Pore Network Model, Zhenyu Xu

Theses and Dissertations

In our first model, an internal and external coupled solver is presented to simulate the slow drying of a porous medium placed adjacent to a laminar flow of air in a slit. The porous medium is represented by a 20×20 pore-network model: the invasion-percolation algorithm is employed to simulate moisture redistribution; water-vapor migration in empty network is estimated using the purely diffusive approach. The external flow-field, unchanged during the drying simulation, is computed in the beginning using the Navier-Stokes equations. Subsequent water-vapor transport is modeled using a convection-diffusion type transport equation. A unique pore-to-cell meshing method and a novel unified …

Design And Optimization Of Hybrid Energy Storage For Photovoltaic Power Fluctuation Smoothing Based On Frequency Analysis, Ruirui Yang

Theses and Dissertations

A proper design of energy storage system (ESS) can effectively smooth the photovoltaic (PV) output power fluctuation, lower the cost, and improve the power quality and stability.

According to the response characteristics of different energy storage equipment, an optimal hybrid EES sizing method is proposed based on frequency analysis. A hybrid ESS including lead-acid battery, lithium battery and electric double-layer capacitor (EDLC) is selected to smooth out PV power fluctuation and meet both power and energy requirement of the power grid. Fast Fourier Transform (FFT) method is applied for analyzing the spectrum of unwanted PV fluctuation. From the FFT analysis, …

Numerical And Experimental Study Of Liquid Breakup Process In Solid Rocket Motor Nozzle, Yi-Hsin Yen

Theses and Dissertations

Rocket propulsion is an important travel method for space exploration and national defense, rockets needs to be able to withstand wide range of operation environment and also stable and precise enough to carry sophisticated payload into orbit, those engineering requirement makes rocket becomes one of the state of the art industry. The rocket family have been classified into two major group of liquid and solid rocket based on the fuel phase of liquid or solid state. The solid rocket has the advantages of simple working mechanism, less maintenance and preparing procedure and higher storage safety, those characters of solid rocket …

Analysis, Design And Implementation Of A Resonant Solid State Transformer, Mohamad Zouheir Sabbah

Theses and Dissertations

This thesis discusses the design of a full-bridge resonant LLC Solid State Transformer. The proposed topology uses a high-frequency transformer which helps minimizing its cost and size, and enables operating at varying load conditions. By using a resonant circuit, soft switching is achieved. Commutation techniques are discussed, namely ZVS and ZCS. Both concepts are applied on different legs of the H-bridge. Pulse frequency modulation (PFM) and Phase Shifting Modulation (PSM) are utilized to control this resonant converter. One of the requirements of this work is to achieve a tightly regulated DC bus voltage. This was shown to be achieved using …

Embodying The Regime Of Automobility: A Phenomenology Of The Driving Subject And The Affects Of Governable Space, George Ananchev

Theses and Dissertations

Automobility describes the car as a particularly universalized form of mobility, a dominant ‘regime’ that locks social life into ‘coercive flexibility’. Despite its liberatory promise and its capacity to emancipate people from the restrictions of physical distance, the car is perhaps the most regulated and controlled commodity that Americans live with today, implicating them in the production of driving subjectivities. This research uses ride-along interviews to inquire into the ways that people’s emotional, bodily, and affective relationships to the practice of driving contribute to the reproduction of the regime of automobility. When we ask questions regarding how power is embodied …