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Development Of The Modified Hot Box: A Convective Heat Transfer Device For Measuring The Steady State And Transient Thermal Properties Of Non-Homogenous Building Materials, Stephen K. Smith Ii

All Theses

The literature data on fired clay brick and other building materials is limitedin scope, necessitating better data for more accurate modeling. A convective heattransfer device for measuring the thermal properties of building materials wasdesigned based on the existing hot box method. This new device is suited tomaterials whose heterogeneous structure does not allow the use of existingdevices such as laser flash or transient plane sensor apparatuses. This device,known as the Modified Hot Box, uses Peltier thermoelectric modules to create aclimate-controlled environment in highly insulated dual chambers. The ModifiedHot Box was calibrated to acquire data that can be used to calculate …

Quantification Of Volatile Residuals In Polydioxanone By Gas Chromatography: Method Development, Validation And Implementation, Clayton Joseph Culbreath

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Bioresorbable polymers are increasingly utilized for implantable medical devices to avoid complications related to explant and/or long term responses to foreign materials. As with all polymeric materials, residual levels of unreacted monomer, and other volatiles, drastically affect the mechanical and chemical properties as well as the parameters required to process the material into a device. The 1,4-dioxane-2-one (PDO) monomer is a six membered ring that forms an ether-ester polymer via ring-opening polymerization (ROP) with intermediate absorption rate properties that are ideal for numerous implant situations. Developing devices using poly(1,4-dioxane-2-one) (PPDO, PDO, PDX, PPDX, or PDS) is complicated by residual levels …

Vanadium Diselenide: On The Verge Of Charge Density Wave, Menghan Zhou

All Dissertations

Charge density wave (CDW) is a many-body state of matter in which both lattice and electron density are modulated by a new periodicity. CDW features discrete translational symmetry breaking, and mostly occurs in low-dimensional materials. Although CDW behaviors have been found in many materials, the underlying mechanism and the driving forces of CDW transition are still unclear. In particular, the origin of CDW in two-dimensional materials, especially in layered transition metal dicalchogenides (TMDCs), may be distinct from that in one-dimensional materials.

In this dissertation, the CDW transition in VSe2, a layered TMDC material, is explored. Density functional theory (DFT) calculations …

A Study Of The Static Bicycle Reposition Problem With A Single Vehicle, Ling Zu

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The Bicycle Sharing System (BSS), a public service system operated by the government or a private company, provides the convenient use of a bicycle as a temporary method of transportation. More specifically, this system allows people to rent a bike from one location, use it for a short time period and then return it to either to the same or a different location for an inexpensive fee. With the development of IT technology in the 1990s, it became possible to balance the bicycle inventory among the various destinations. In fact, a critical aspect to maintaining a satisfactory BSS is effectively …

Physics-Based Models For Engine System Studies: Quasi-D Dual-Fuel Combustion And Real-Time Intake Charge Flow Estimation, Shuonan Xu

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Ever tightening emissions and fuel economy regulations provide a strong impetus for research on high-efficiency low-emission engine concepts. In addition, CO2 emission regulation and energy security considerations motivate investigations focused on alternative fuels. In the current heavy-duty fleet, diesel engines dominate the market due to their unmatched thermal efficiency. Nevertheless, they suffer from NOx and soot emissions and require complex aftertreatment systems to meet stringent regulations. Due to recent advancements of the Natural Gas (NG) extraction technology, its supply has become increasingly abundant. Conversion of Heavy Duty engines to NG operation provides a most effective way of increasing utilization of …

Gravitation And Cosmology With York Time, Philipp Roser

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Despite decades of inquiry an adequate theory of 'quantum gravity' has remained elusive, in part due to the absence of data that would guide the search and in part due to technical difficulties, prominently among them the 'problem of time'. The problem is a result of the attempt to quantise a classical theory with temporal reparameterisation and refoliation invariance such as general relativity. One way forward is therefore the breaking of this invariance via the identification of a preferred foliation of spacetime into parameterised spatial slices. In this thesis we argue that a foliation into slices of constant extrinsic curvature, …

Evaluating Indirect Calorimetry Methodology, Postural Energy Expenditure, And The Effects Of Diet And Exercise Recommendations, Collin Jeffrey Popp

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Scientific research provides the evidence necessary to build an effective framework for health recommendations. In a population of young, healthy adults the recommended duration of an indirect calorimetry measurement period when measuring resting energy expenditure was a minimum of 10 minutes, with the first 5-minutes being discarded. A steady state period was achieved during the second 5-minute segment of a 30-minute period. Furthermore, in a population of young women, short-term standing energy expenditure was statically greater than lying and sitting energy expenditure. However, recommendations to stand instead of sit may be negligible as the magnitude of the effect of short-term …

Affordance-Based Design Product Evolution Using Customer Feedback, Ivan Mata

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Designers can benefit from involving the user in the product development process. Understanding how users perceive products can help designers make decisions that better accommodate user needs. Though several methods have been created that involve the user at different stages of the design process, there is still no clear connection between user perceptions and product improvements. Affordance Based Design (ABD) provides the theoretical background needed to explore such connections. ABD is a systematic de-sign method that uses the concept of affordances to describe the interactions between users and products. The integration of ABD and genetic algorithms (GAs) is proposed as …

Evaluation Of 1,4-Dioxane Biodegradation Under Aerobic And Anaerobic Conditions, Francisco J. Barajas Rodriguez

All Dissertations

Used mainly as a solvent stabilizer, 1,4-dioxane is present at many sites contaminated along with chlorinated solvents and other chemical compounds. Considered a probable human carcinogen by the U.S. Environmental Protection Agency, this contaminant has raised considerable concerns because of its potential adverse effects on health. Therefore, remediation of 1,4-dioxane has gained importance, and although there are several approaches for its treatment, such as ex situ physicochemical processes, bioremediation is a key alternative because it is a low energy demanding process. Anaerobic conditions are present at most contaminated sites, however, there is insufficient scientific evidence for anaerobic biodegradation of 1,4-dioxane. …

Analysis Of High Pressure H2/O2, H2/Air And Kerosene/Air Reacting Shear Flows, Ayse Korucu

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Direct Numerical Simulation (DNS) data for high pressure H₂/O₂ and H₂/Air flames using the compressible flow formulation, detailed kinetics, a real fluid equation of state, and generalized diffusion are analyzed. The DNS is filtered over a range of filter widths to provide exact terms in the Large Eddy Simulation (LES) governing equations, including unclosed terms. The filtered heat flux vector is extensively compared with the heat flux vector calculated as a function of the filtered primitive variables (i.e. the exact LES term is compared with its form available within an actual LES). The difference between …

Towards Structuring Smart Grid: Energy Scheduling, Parking Lot Allocation, And Charging Management, Mehdi Rahmani-Andebili

All Dissertations

Nowadays, the conventional power systems are being restructured and changed into smart grids to improve their reliability and efficiency, which brings about better social, economic, and environmental benefits. To build a smart grid, energy scheduling, energy management, parking lot allocation, and charging management of plug-in electric vehicles (PEVs) are important subjects that must be considered. Accordingly, in this dissertation, three problems in structuring a smart grid are investigated.

The first problem investigates energy scheduling of smart homes (SHs) to minimize daily energy consumption cost. The challenges of the problem include modeling the technical and economic constraints of the sources and …

Radiative Transfer Using Path Integrals For Multiple Scattering In Participating Media, Paul Michael Kilgo

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The theory of light transport forms the basis by which many computer graphic renderers are implemented. The more general theory of radiative transfer has applications in the wider scientific community, including ocean and atmospheric science, medicine, and even geophysics. Accurately capturing multiple scattering physics of light transport is an issue of great concern. Multiple scattering is responsible for indirect lighting, which is desired for images where high realism is the goal. Additionally, multiple scattering is quite important for scientific applications as it is a routine phenomenon. Computationally, it is a difficult process to model. Many have developed solutions for hard …

Complex Network Analysis And The Applications In Vehicle Delay-Tolerant Networks, Bo Wu

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Vehicle Delay Tolerant Networks (VDTNs) is a particular kind of Delay Tolerant Networks (DTNs), where vehicles equipped with transmission capabilities are interconnected to form Vehicle NETworks (VNETs). Some applications and services on the top of VDTNs have raised a lot of attention, especially by providing information about weather conditions, road safety, traffic jams, speed limit, and even video streamings without the need of infrastructures. However, due to features such as high vehicle mobility, dynamic scenarios, sparsity of vehicles, short contact durations, disruption and intermittent connectivity and strict requirements for latency, many VDTNs do not present satisfactory performance, because no path …

A Multi-Model Approach To Design A Robust Fixed-Order Controller To Improve Power System Stability, Abdlmnam Abdlrahem Abdlrahem

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The rapid increase in power system grid has resulted in additional challenges to reliable power transfer between interconnected systems of a large power network. Large-scale penetration of intermittent renewable energy increases uncertainty and variability in power systems operation. For secure operation of power systems under conditions of variability, it is imperative that power system damping controllers are robust. Electromechanical oscillations in the range of 0.2 Hz to 1 Hz are categorized as inter-area modes. These modes arise due primarily to the weak interconnections characterized by long transmission lines between different operating areas of an interconnected power system. One of the …

Characterizing The Performance Of A Ferrofluid-Based Electromagnetic Energy Harvester Under Direct And Parametric Excitations, Saad F. Alazemi

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When a container carrying a magnetized ferrofluid is subjected to external mechanical stimuli, the sloshing motion of the magnetized ferrofluid generates a time-varying magnetic flux, which can be used to induce an electromotive force in a coil placed adjacent to the container. This process generates an electric current in the coil, and therewith, can be used to transduce external vibrations into electric energy providing a unique approach for vibration energy harvesting using liquid-state transduction materials. As compared to traditional vibratory energy harvesters that employ soli transduction elements, this approach offers several advantages including, but not limited to, conformability to different …

Accelerating Big Data Analytics On Traditional High-Performance Computing Systems Using Two-Level Storage, Pengfei Xuan

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High-performance Computing (HPC) clusters, which consist of a large number of compute nodes, have traditionally been widely employed in industry and academia to run diverse compute-intensive applications. In recent years, the revolution in data-driven science results in large volumes of data, often size in terabytes or petabytes, and makes data-intensive applications getting exponential growth. The data-intensive computing presents new challenges to HPC clusters due to the different workload characteristics and optimization objectives. One of those challenges is how to efficiently integrate software frameworks developed for big data analytics, such as Hadoop and Spark, with traditional HPC systems to support both …

Effects Of Mismatched Math Self-Efficacy And Performance On Behaviors And Attitudes Of Engineering Students With Poor Math Preparation, Gustavo Moran

All Dissertations

This research is a sequential explanatory mixed methods study seeking to understand the influences of mathematics self-efficacy (math SE) on the behavior and attitudes of engineering students with poor math preparation behavior and attitudes in their first college math courses.

The quantitative phase of this research assessed the math SE of engineering students placed in non-college-level math courses at Clemson University. A total of 408 students completed a survey to classify their math SE level; based on the results of the quantitative data analysis, 11 engineering students were selected from different semesters between the Spring 2014 and Spring 2016 to …

Optimal Design Of Process Parameters During Laser Direct Metal Deposition Of Multi-Material Parts, Jingyuan Yan

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During the past few years, the need for multi-material parts or heterogeneous objects (HOs) has surfaced with the rapid growth of laser technology, material science and additive manufacturing techniques. Direct Metal Deposition (DMD) process, a metal based additive manufacturing technique, can locally deposit dissimilar metal powders to produce HOs as needed. While some theoretical and experimental studies have been conducted to investigate the DMD process, there are still some challenges such as the process parameters design, optimization, and adjustment during the fabrication of HOs that have not been well elucidated. This dissertation aims at developing the manufacturing science needed to …

Kernel Smoothing And Tolerance Intervals For Hierarchical Data, Christopher Wilson

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Multistage sampling is a common sampling technique in many studies. A challenge presented by multistage sampling schemes is that an additional random term should be introduced to the linear model. Observations are identically distributed but not independent, thus many traditional kernel smoothing techniques, which assume that the data is independent and identically distributed, may not produce reasonable estimates for the marginal density. Breunig (2001) proposed a method to account for the intra-class correlation leading to a complex bandwidth involving high order derivatives for bivariate kernel density estimate. We consider an alternative approach where the data are grouped into multiple random …

Formulation Of An Interactive Ruled-Based Design Envelope For Ensuring Aftermarket Vehicle Dynamics Compliance, Xianjie Zhou

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The objective of this research is to develop an integrated system engineering methodology for the customization design to maximize vehicle performance upgrade freedom while ensuring vehicle dynamics compliance. A post-delivery modification framework, which is led by an aftermarket umbrella organization and involve various stakeholders has been established. The umbrella organization will be in charge of developing the design envelope and distribute to various aftermarket kit suppliers to generate specific products according to their brand essence. A generic mathematical representation of a (proprietary) ESC system has been developed for virtual certification purposes. This approach is a cost-effective alternative to physical on-road …

Efficient Analytics For Large Implicit Correlation Networks, Raghuveer Mohan

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Large “correlation”-type networks have applications in machine learning, data mining and analysis of large biological networks. These networks contain short length-k (on the order of thousands) feature vectors for every node in the network that describe the characteristic or behavior of that node. Edges between nodes are expressed as correlations, partial correlations or coherence between the corresponding feature vectors. If the number of nodes n is too large (on the order of millions), then the dense correlation network with size n×n is computationally infeasible even to explicitly store in memory, let alone to use for computation of standard network analytics …

Characterization And Modeling Of Bond-Loss Behavior In Pretensioned Concrete I-Girders, Behnam Naji

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Bond-loss failures have been widely observed in load tests of precast-pretensioned concrete I-girders. This type of failure is associated with shear cracking near the support that interrupts anchorage of the strands, leading to loss of bond and slipping of the strands relative to the concrete. It has been experimentally demonstrated that this failure type can occur at load levels that are lower than the nominal shear and flexural capacities. Because bond loss can be the controlling factor for structural capacity, it is critical that strand anchorage be considered when detailing and calculating the capacity of I-girder end regions. This dissertation …

Conjugated Polymers Under Confinement: Molecular Dynamics Simulations Study, Sabina Maskey

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The conformations and dynamics of luminescent polymers, polymeric nanoparticles or polydots and polymers grafted onto inorganic nanoparticles using molecular dynamics (MD) simulation have been studied. Rigidity of the backbones of polymers effects their properties. Model polymer, dialkyl poly para phenylene ethynylene (PPE), comprises rigid backbones substituted by flexible side chains. The degree of conjugation of these polymers depends on the conformation of their backbones, which in turn affects their electronic and luminescence characteristics. The results of single chain of PPEs followed by polydots and polymers grafted onto inorganic nanoparticles. PPEs as a function of molecular weight and the nature of …

Fluorescent Methods For Investigating Metabolic Processes In Trypanosoma Brucei, Sheng Lin

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Trypanosoma brucei is a unicellular kinetoplastid protozoan that is the causative agent of Human African Trypanosomiasis, or Sleeping Sickness. Combating these protozoan pathogens presents an ongoing challenge due to their efficient immune evasion strategies, lack of effective vaccines, poor drugs and emerging drug resistance, and the general lack of knowledge of their unique biological processes. Among one of the most important biological pathways for kinetoplastid protozoans is the synthesis of ATP from glucose within glycosome organelles. Glycosomes are related to mammalian peroxisomes, but differ in having a fully compartmentalized glycolysis pathway in addition to basic peroxisomal functions. While equivalent processes …

The Intentionality Of Coaching Responses: Connecting Stances To Practices, Leigh Martin

All Dissertations

Limited research exists that highlights instructional coaching practices associated with teacher learning, practice, and student learning (McGatha, Davis, & Stokes, 2015; Gibbons & Cobb, 2011). This study investigates coaching as a high-leverage strategy for mathematics teacher learning as a way to contribute to this research base. My study examines one coach's practices with two different teachers in order to respond to questions in the field about the decision-making processes of coaches. More specifically, this study examines how one coach determined which practices to use and the ways in which one coach adapted her practices with teachers. This dissertation seeks to …

Ceramic Thin Films With Embedded Magnetic Nanofibers Or Nanorods Of Controlled Orientations, Zhaoxi Chen

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Ceramic thin films embedded with oriented magnetic nanofibers or nanorods are highly demanded for the applications in remote sensing, electromagnetic shielding, and thermal management at high temperatures. The general strategy for developing ceramic composite thin films with aligned magnetic nanorods or nanofibers has not been developed yet. This dissertation is centered on fundamentally understanding a sol-gel and polymer-based route towards creation of ceramic thin films with aligned magnetic nanostructures. The topics cover fabrication and properties of ceramic and ceramic-based nanofibers, precipitating magnetic nanoparticles within ceramic fibers, aligning and embedding nanofibers or nanorods within ceramic films, and preventing cracking during the …

On The Modal Effective Nonlinearity Of A Class Of Tapered-Cantilever Beams, Clodoaldo Jose Da Silva

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The objective of this dissertation is to investigate the influence of i) higher-order nonlinearities, and ii) assumed mode discretization on the approximate modal effective nonlinearity associated with the flexural response of thin metallic cantilever beams of a constant thickness and a linearly-varying width. To this end, in the first part of this dissertation, a nonlinear model of an Euler-Bernoulli metallic cantilever beam with an arbitrarily variable cross-section is derived. Unlike the common literature wherein the Lagrangian is truncated using a fourth-order Taylor series; here the series is truncated at the eighth order to study the influence of higher-order nonlinearities on …

Synchrony In A Boolean Network Of The L-Arabinose Operon In Escherichia Coli, Andy Jenkins, Matthew Macauley

Publications

The lactose operon in Escherichia coli was the first known gene regulatory network, and it is frequently used as a prototype for new modeling paradigms. Historically, many of these modeling frameworks use differential equations. More recently, Stigler and Veliz-Cuba proposed a Boolean network model that captures the bistability of the system and all of the biological steady states. In this paper, we model the well-known arabinose operon in E. coli with a Boolean network. This has several complex features not found in the lac operon, such as a protein that is both an activator and repressor, a DNA looping mechanism …

Characterizing Teaching Assistants’ Knowledge And Beliefs Following Professional Development Activities Within An Inquiry-Based General Chemistry Context, Lindsay B. Wheeler, Jennifer L. Maeng, Brooke A. Whitworth

Publications

The purpose of this investigation was to explore changes in undergraduate and graduate teaching assistants’ (TAs’) content knowledge and beliefs about teaching within the context of an inquiry-based laboratory course. TAs received professional development (PD), which was informed by the TA training literature base and was designed for TAs implementing a guided inquiry approach to general chemistry laboratory instruction. TAs engaged in ∼20 h of presemester PD and ∼30 h of weekly follow-up PD during the semester. The study utilized a multiple-methods approach within a social constructivist framework to assess changes in the TAs. Participants included eight graduate TAs and …

Approximate Time To Steady-State Resting Energy Expenditure Using Indirect Calorimetry In Young, Healthy Adults, Collin J. Popp, Jocelyn J. Tisch, Kenan E. Sakarcan, William C. Bridges, Elliot D. Jesch

Publications

Indirect calorimetry (IC) measurements to estimate resting energy expenditure (REE) necessitate a stable measurement period or steady state (SS). There is limited evidence when assessing the time to reach SS in young, healthy adults. The aims of this prospective study are to determine the approximate time to necessary reach SS using open-circuit IC and to establish the appropriate duration of SS needed to estimate REE. One hundred young, healthy participants (54 males and 46 females; age = 20.6 ± 2.1 years; body weight = 73.6 ± 16.3 kg; height 172.5 ± 9.3 cm; BMI = 24.5 ± 3.8 kg/m^{2 …}