Physical Sciences and Mathematics Commons^™

System Characterizations And Optimized Reconstruction Methods For Novel X-Ray Imaging, Huifeng Guan

McKelvey School of Engineering Theses & Dissertations

In the past decade there have been many new emerging X-ray based imaging technologies developed for different diagnostic purposes or imaging tasks. However, there exist one or more specific problems that prevent them from being effectively or efficiently employed. In this dissertation, four different novel X-ray based imaging technologies are discussed, including propagation-based phase-contrast (PB-XPC) tomosynthesis, differential X-ray phase-contrast tomography (D-XPCT), projection-based dual-energy computed radiography (DECR), and tetrahedron beam computed tomography (TBCT). System characteristics are analyzed or optimized reconstruction methods are proposed for these imaging modalities. In the first part, we investigated the unique properties of propagation-based phase-contrast imaging technique …

Abiotic- And Biotic-Formation Of Manganese Oxides And Their Fate In Environmental Systems, Haesung Jung

McKelvey School of Engineering Theses & Dissertations

Manganese (hydr)oxide (Mn (hydr)oxide) minerals are ubiquitous in aquatic and terrestrial environments. These minerals have high surface areas and are highly sorptive and redox active. From decades of accumulated knowledge about natural redox cycling, we have found that Mn (hydr)oxides play critical roles as electron donors and acceptors in elemental geochemical cycling and biological metabolisms in nature. Thus, Mn (hydr)oxides have garnered increasing interest to understand natural systems. Considering the variety of redox reactions with Mn (hydr)oxides in nature, it is also expected that there should be diverse pathways to form Mn (hydr)oxides through abiotic and biotic processes. Previous studies …

Two-Component Hydrogel As Biomimetic Vitreous Substitutes, Sruthi Santhanam

McKelvey School of Engineering Theses & Dissertations

The vitreous humor of the eye is a biological hydrogel principally composed of fibrillary collagen interspersed with semi-flexible polyelectrolyte, hyaluronic acid (HA). Certain pathological conditions necessitate its removal and replacement. Current vitreous substitutes, such as silicone oils and perfluorocarbons, are hydrophobic, do not resemble the properties of the vitreous, and have known complications. An ideal vitreous substitute should have properties of the natural vitreous, perform its functions, and be biocompatible in the eye. Inspired by the structure and composition of the natural vitreous, we used bio-mimicry to develop an injectable two-component hydrogel. The hydrogel is composed of a fibrillary gellan, …

System Optimization And Iterative Image Reconstruction In Photoacoustic Computed Tomography For Breast Imaging, Yang Lou

McKelvey School of Engineering Theses & Dissertations

Photoacoustic computed tomography(PACT), also known as optoacoustic tomography (OAT), is an emerging imaging technique that has developed rapidly in recent years. The combination of the high optical contrast and the high acoustic resolution of this hybrid imaging technique makes it a promising candidate for human breast imaging, where conventional imaging techniques including X-ray mammography, B-mode ultrasound, and MRI suffer from low contrast, low specificity for certain breast types, and additional risks related to ionizing radiation. Though significant works have been done to push the frontier of PACT breast imaging, it is still challenging to successfully build a PACT breast imaging …

Improving Pure-Tone Audiometry Using Probabilistic Machine Learning Classification, Xinyu Song

McKelvey School of Engineering Theses & Dissertations

Hearing loss is a critical public health concern, affecting hundreds millions of people worldwide and dramatically impacting quality of life for affected individuals. While treatment techniques have evolved in recent years, methods for assessing hearing ability have remained relatively unchanged for decades. The standard clinical procedure is the modified Hughson-Westlake procedure, an adaptive pure-tone detection task that is typically performed manually by audiologists, costing millions of collective hours annually among healthcare professionals. In addition to the high burden of labor, the technique provides limited detail about an individual’s hearing ability, estimating only detection thresholds at a handful of pre-defined pure-tone …

Numerical Methods For Nonlinear Optimal Control Problems And Their Applications In Indoor Climate Control, Runxin He

McKelvey School of Engineering Theses & Dissertations

Efficiency, comfort, and convenience are three major aspects in the design of control systems for residential Heating, Ventilation, and Air Conditioning (HVAC) units. In this dissertation, we study optimization-based algorithms for HVAC control that minimizes energy consumption while maintaining a desired temperature, or even human comfort in a room. Our algorithm uses a Computer Fluid Dynamics (CFD) model, mathematically formulated using Partial Differential Equations (PDEs), to describe the interactions between temperature, pressure, and air flow. Our model allows us to naturally formulate problems such as controlling the temperature of a small region of interest within a room, or to control …

Aluminosilicate Dissolution And Silicate Carbonation During Geologic Co2 Sequestration, Yujia Min

McKelvey School of Engineering Theses & Dissertations

Geologic CO2 sequestration (GCS) is considered a promising method to reduce anthropogenic CO2 emission. Assessing the supercritical CO2 (scCO2)¬–gas or liquid phase water (g, l)–mineral interactions is critical to evaluating the viability of GCS processes. This work contributes to our understanding of geochemical reactions at CO2¬–water (g, l)–mineral interfaces, by investigating the dissolution of aluminosilicates in CO2-acidified water (l). Plagioclase and biotite were chosen as model minerals in reservoir rock and caprock, respectively. To elucidate the effects of brine chemistry, first, the influences of cations in brine including Na, Ca, and K, have been investigated. In addition to the cations, …

Synthesis, Characterization, And Biological Activity Of Spherical Nucleic Acid (Sna) Constructs For Cancer Therapy And Imaging, Colin Calabrese

Arts & Sciences Electronic Theses and Dissertations

This dissertation focuses on the development of biocompatible oligonucleotide-based nanomaterials, known as spherical nucleic acids (SNAs), as therapeutic and diagnostic agents for intracellular gene regulation and in vivo cancer imaging by positron emission tomography (PET). SNAs consist of a nanoparticle core functionalized with a dense shell of oligonucleotides such as deoxyribonucleic acid (DNA). Detailed synthetic procedures and characterization of novel SNAs with purpose-built biocompatible core materials are described. The SNAs exhibit comparable chemical, physical and biological properties regardless of core composition. The functionalities of the SNAs were further tailored by deliberate design and chemical modification of their oligonucleotide sequences.

The …

Studies In Pressurized Oxy-Combustion: Process Development And Control Of Radiative Heat Transfer, Akshay Gopan

McKelvey School of Engineering Theses & Dissertations

Fossil fuels supply over 80% of the world’s primary energy and more than two-thirds of the world’s electricity. Of this, coal alone accounts for over 41% of the electricity supplied globally. Though coal is globally well-distributed and can provide stable and reliable energy on demand, it emits a large amount of carbon dioxide—a greenhouse gas responsible for global warming. Serious concerns over the implication of the increased global temperature have prompted the investigation into low carbon energy alternatives. The idea of capturing the carbon dioxide emitted from the combustion sources is considered as one of the viable alternatives. This would …

Decoupling Information And Connectivity In Information-Centric Networking, Hila Ben Abraham, Jyoti Parwatikar, John Dehart, Adam Drescher, Patrick Crowley

All Computer Science and Engineering Research

This paper introduces and demonstrates the concept of Information-Centric Transport as a mechanism for cleanly decoupling the information plane from the connectivity plane in Information-Centric Networking (ICN) architectures, such as NDN and CICN. These are coupled in today's incarnations of NDN and CICN through the use of forwarding strategy, which is the architectural component for deciding how to forward packets in the presence of either multiple next-hop options or dynamic feedback. As presently designed, forwarding strategy is not sustainable: application developers can only confidently specify strategy if they understand connectivity details, while network node operators can only confidently assign strategies …

An Improved Algorithm For Learning To Perform Exception-Tolerant Abduction, Mengxue Zhang

McKelvey School of Engineering Theses & Dissertations

Abstract

Inference from an observed or hypothesized condition to a plausible cause or explanation for this condition is known as abduction. For many tasks, the acquisition of the necessary knowledge by machine learning has been widely found to be highly effective. However, the semantics of learned knowledge are weaker than the usual classical semantics, and this necessitates new formulations of many tasks. We focus on a recently introduced formulation of the abductive inference task that is thus adapted to the semantics of machine learning. A key problem is that we cannot expect that our causes or explanations will be perfect, …

The Effect Of Diffusive Transport On Mineral Carbonation In Geologic Carbon Sequestration, Wei Xiong

McKelvey School of Engineering Theses & Dissertations

Geologic carbon sequestration (GCS) is an effective method to mitigate environmental problems due to excessive anthropogenic CO2 emissions. It involves injecting supercritical CO2 into deep geologic formations in which CO2 will ultimately be converted to solid carbonate minerals. Basalt is a promising host rock that is rich in the divalent cations Ca, Mg and Fe that are important for mineral trapping of CO2. Fractures and pores in basalt reservoirs provide substantial surface area for geochemical reactions during carbon sequestration. The transport in fractures and pores is controlled by diffusion. The coupling of diffusive transport and geochemical reactions leads to carbonate …

Sub 2 Nm Particle Characterization In Systems With Aerosol Formation And Growth, Yang Wang

McKelvey School of Engineering Theses & Dissertations

Aerosol science and technology enable continual advances in material synthesis and atmospheric pollutant control. Among these advances, one important frontier is characterizing the initial stages of particle formation by real time measurement of particles below 2 nm in size. Sub 2 nm particles play important roles by acting as seeds for particle growth, ultimately determining the final properties of the generated particles. Tailoring nanoparticle properties requires a thorough understanding and precise control of the particle formation processes, which in turn requires characterizing nanoparticle formation from the initial stages. The knowledge on particle formation in early stages can also be applied …

Measuring Molecular Orientation And Rotational Mobility Using A Tri-Spot Point Spread Function, Oumeng Zhang

McKelvey School of Engineering Theses & Dissertations

Single molecules have become a powerful tool for biophysicists since they were first optically detected 28 years ago. Understanding molecular orientation can not only improve the accuracy of single-molecule localization, but it can also provide insight into biochemical behaviors at the nanoscale. In this thesis, I present a method to measure the molecular orientation and rotational mobility of single-molecule emitters by designing and implementing a tri-spot point spread function. The point spread function is designed so that it is capable of measuring all degrees of freedom related to molecular orientation and rotational mobility. Its design is optimized by maximizing the …