Digital Commons Network^™

Essays In Directed Technical Change, Randy Cragun

All Dissertations

This dissertation takes the position that a scientific theory ought to be general and parsimonious and apply this rule to Daron Acemoglu's theory of directed technical change to show that the theory provides useful structure for our knowledge of human capital and wages. The first chapter estimates the shape of labor demand and the strength of technical bias by age group in the US while taking account of changes in directed technology that shift relative demand for worker age groups. The data are consistent with demand shifts produced from the theory of directed technical change when the elasticity of substitution …

Problems In Domination And Graph Products, Jason Todd Hedetniemi

All Dissertations

The 'domination chain,'' first proved by Cockayne, Hedetniemi, and Miller in 1978, has been the focus of much research. In this work, we continue this study by considering unique realizations of its parameters. We first consider unique minimum dominating sets in Cartesian product graphs. Our attention then turns to unique minimum independent dominating sets in trees, and in some direct product graphs. Next, we consider an extremal graph theory problem and determine the maximum number of edges in a graph having a unique minimum independent dominating set or a unique minimum maximal irredundant set of cardinality two. Finally, we consider …

Administrative Best Practices To Influence Culture In A Rural Middle School Of Poverty, John David Nixon

All Dissertations

Studies have shown a direct correlation between positive school culture and increases in student achievement (Bulach et al, 1995; Goddard et al, 2000; Kaplan & Owings, 2013; McCarley et al, 2014; Thapa et al, 2013; Whitaker, 2001). The literature also suggests that the culture within a school can be positively impacted through effective leadership (Hallinger, et al, 2014), but the literature available for rural schools in regards to student achievement and culture is limited (Arnold, et al, 2005 and Lee, 2001). This purpose of this mixed-method case study is to identify what practices a principal employed to create a change …

Hyperspectral Diffuse Optical Tomography Using The Reduced Basis Method And Sparsity Constraints, Rachel Elizabeth Grotheer

All Dissertations

Diffuse Optical Tomography (DOT) has long been investigated as an effective imaging technique for soft tissue imaging, such as breast cancer detection. DOT has many benefits, including its use of non-ionizing light and its ability to produce high contrast images, but it also has low resolution. In recent years hyperspectral DOT (hyDOT) has been proposed, in an effort to improve that resolution by adding more information in the spectral domain. In this imaging modality, hundreds or even thousands of different wavelengths in the visible to near infrared range are used in the imaging process. Since tissue absorbs and scatters light …

Software Development And Platform Adoption As Successive Games Of Real Options Investment And Valuation, John Yates Monteith

All Dissertations

Platform based software engineering is at the heart of a new mode software product development in the context of software ecosystems. In this setting, an organization develops a software platform with the intention of providing that platform for use and extension by software-producing organizations. Multiple benefits arise from engaging in platform-based software engineering from both the perspective of the platform developer and the software product developer, including decreased time to market, defrayed cost of development and increased software quality. Organizations have been engaging in platform-based software engineering for years, exemplified by cases such as Eclipse, Android and SAP. However, the …

Generalized Colorings Of Graphs, Honghai Xu

All Dissertations

A graph coloring is an assignment of labels called “colors” to certain elements of a graph subject to certain constraints. The proper vertex coloring is the most common type of graph coloring, where each vertex of a graph is assigned one color such that no two adjacent vertices share the same color, with the objective of minimizing the number of colors used. One can obtain various generalizations of the proper vertex coloring problem, by strengthening or relaxing the constraints or changing the objective. We study several types of such generalizations in this thesis. Series-parallel graphs are multigraphs that have no …

Defect Assisted Growth Of Copper-Silicide Nanostructures On Si(100) And Si(111), Endu Sekhar Srinadhu

All Dissertations

As the dimensions of the smallest feature on the integrated circuit has minia-turized into the range of tens of nanometers, patterning of highly ordered nanos-tructures with tunable size and shape in large scale on the surface of substrate is highly demanding and increasingly challenges the limits of nanolithography. To over-come the conventional lithographic limitations, self assembled methods have been explored. While strain driven self assembly is widely viewed as a promising technique for patterning at the nanoscale, to follow this approach and create structures in a desired manner, a reliable means to engineer and characterize the shape and sizes of …

Expander Graphs And Coding Theory, Michael C. Dowling Jr.

All Dissertations

Expander graphs are highly connected sparse graphs which lie at the interface of many different fields of study. For example, they play important roles in prime sieves, cryptography, compressive sensing, metric embedding, and coding theory to name a few. This thesis focuses on the connections between sparse graphs and coding theory. It is a major challenge to explicitly construct sparse graphs with good expansion properties, for example Ramanujan graphs. Nevertheless, explicit constructions do exist, and in this thesis, we survey many of these constructions up to this point including a new construction which slightly improves on an earlier edge expansion …

Exploiting Stiffness Nonlinearities To Improve The Performance Of Galloping Flow Energy Harvesters, Ali H. Alhadidi

All Dissertations

Fluid-structure coupling mechanisms such as galloping and wake galloping have recently emerged as effective methods to develop scalable flow energy harvesters (FEHs) that can be used to power remote sensors and sensor networks. The oper-ation concept of these devices is based on coupling the pressure forces culminating from the motion of the fluid past a mechanical oscillator to its natural modes of vibration. As a result, the mechanical oscillator undergoes large-amplitude motions that can be transformed into electricity by utilizing an electromechanical transduc-tion mechanism, which is generally piezoelectric or electromagnetic in nature. Due to their scalability and design simplicity, FEHs …

Formulation And Characterization Of An Antimicrobial Coating Containing Nisin For Large Scale Food Package Converting Processes, Michele Christine Perna

All Dissertations

This research consisted of formulating an antimicrobial coating containing Nisaplin® intended for large scale production and inhibition of spoilage microorganisms. Secondly, the coating formulated was applied to a flexible film surface using two trials (gravure and flexography) commonly used in large scale food package coating or printing processes. In addition, diffusion and mass transfer theory was applied to discuss the many complications of predicting nisin diffusion or release from a coated material for antimicrobial food packaging applications.

Previous work conducted by predecessors, produced an antimicrobial coating formulation using a 70/30 Methylcellulose/Hydroxypropyl methylcellulose base (MC/HPMC). Some disadvantages of this coating included …

The Impact Of Leadership On School Culture And Student Achievement, Matthew Joseph Piotrowsky

All Dissertations

This study examined the predictive relationship of school leadership on school culture. Given the demands of standards based education reform, the goal of every school is student achievement. The literature review examines the previous studies showing significance of leadership on culture, leadership on teacher retention, and leadership and school culture on student achievement. This study uses the School Culture Survey developed by Gruenert and Valentine (1998). It is a 35-item Likert-scale survey defining six variables; Collaborative Leadership, Teacher Collaboration, Professional Development, Unity of Purpose, Collegial Support, and Learning Partnerships. The survey was distributed electronically to an upstate South Carolina school …

Design, Modeling And Control Of A Thermal Management System For Hybrid Electric Vehicles, Xinran (William) Tao

All Dissertations

Hybrid electric vehicle (HEV) technology has evolved in the last two decades to become economically feasible for mass produced automobiles. With the integration of a lithium battery pack and electric motors, HEVs offer a significantly higher fuel efficiency than traditional vehicles that are driven solely by an internal combustion engine. However, the additional HEV components also introduce new challenges for the powertrain thermal management system design. In addition to the common internal combustion engine, the battery pack, the generator(s), as well as the electric motor(s) are now widely applied in the HEVs and have become new heat sources and they …

A Qualitative Study Of African American Women In Engineering Technology Programs In Community Colleges, Jacquelyn Blakley

All Dissertations

This study examined the experiences of African American women in engineering technology programs in community colleges. There is a lack of representation of African American women in engineering technology programs throughout higher education, especially in community/technical colleges. There is also lack of representation of African American women in careers related to engineering. The enrollment for African American women students in engineering technology programs is minimal compared to the overall student enrollment in the programs. Previous research focuses on minorities in engineering programs in higher education but does not focus specifically on African American women in engineering technology programs in community …

Light Echoes And Late-Time Emissions Of Type Ia Supernovae, Dina Drozdov

All Dissertations

Type Ia supernovae have many applications in astronomy, yet with fundamental properties still not fully understood, new methods for investigating the environment of a supernova need to be developed. A light echo is produced from the scattering of light from a bright source and can be used to analyze the dust in the vicinity of the supernova and learn invaluable information about the source. These techniques can put constraints on explosion and progenitor models. Although light echo detections from Type Ia supernovae are rare, with only seven total extragalactic detections, this could be due to the lack of thorough late-epoch …

Wide Area Signals Based Damping Controllers For Multimachine Power Systems, Ke Tang

All Dissertations

Nowadays, electric power systems are stressed and pushed toward their stability margins due to increasing load demand and growing penetration levels of renewable energy sources such as wind and solar power. Due to insufficient damping in power systems, oscillations are likely to arise during transient and dynamic conditions. To avoid undesirable power system states such as tripping of transmission lines, generation sources, and loads, eventually leading to cascaded outages and blackouts, intelligent coordinated control of a power system and its elements, from a global and local perspective, is needed. The research performed in this dissertation is focused on intelligent analysis …

Investigation Of Advanced Engine Cooling Systems - Optimization And Nonlinear Control, Tianwei (Thomas) Wang

All Dissertations

Advanced automotive engine cooling systems can positively impact the performance, fuel economy, and reliability of internal combustion engines. A smart engine cooling system typically features multiple real time computer controlled actuators: a three way linear smart valve, a variable speed coolant pump, and electric radiator fan(s). In this dissertation, several innovative comprehensive nonlinear control and optimization operation strategies for the next generation smart cooling application will be analyzed. First, the optimal control has been investigated to minimize the electric energy usage of radiator fan matrix. A detailed mathematical model of the radiator fan(s) matrix operation and the forced convection heat …

Manufacturing System Energy Modeling And Optimization, Lujia Feng

All Dissertations

World energy consumption has continued increasing in recent years. As a major consumer, industrial activities uses about one third of the energy over the last few decades. In the US, automotive manufacturing plants spends millions of dollars on energy. Meanwhile, due to the high energy price and the high correlation between the energy and environment, manufacturers are facing competing pressure from profit, long term brand image, and environmental policies. Thus, it is critical to understand the energy usage and optimize the operation to achieve the best overall objective. This research will establish systematic energy models, forecast energy demands, and optimize …

Material Characterization And Finite Element Simulations Of Aluminum Alloy Sheets During Non-Isothermal Forming Process, Nan Zhang

All Dissertations

The utilization of more non-ferrous materials is one of the key factors to succeed out of the constantly increasing demand for lightweight vehicles in automotive sector. Aluminum-magnesium alloys have been identified as the most promising substitutions to the conventional steel without significant compromise in structural stiffness and strength. However, the conventional forming methods to deform the aluminum alloy sheets are either costly or insufficient in formability which limit the wide applications of aluminum alloy sheets. A recently proposed non-isothermal hot stamping approach, which is also referred as Hot Blank – Cold Die (HB-CD) stamping, aims at fitting the commercial grade …

Manipulating Cardiovascular Cellular Interactions And Mechanics: A Multidimensional And Multimodal Approach, Aesha Yogesh Desai

All Dissertations

The goal of this dissertation is to better understand cellular mechanics across length scales for the development of computational models of tissue behavior. To this end, we had two major approaches, multidimensional and multimodal. Firstly, to use a model that better mimics in vivo like cellular environment, microtissue (spheroid) cell culture system was used to study cell mechanics. Secondly, a novel technique was designed to study single cell mechanics in multiple dimensions. Cell mechanical properties are directly related to the composition and organization of the cytoskeleton, which is physically coupled to neighboring cells through adherens junctions and to extracellular matrix …

The Tiger Vol. 110 Issue 24 2016-04-11, Clemson University

Tiger Newspapers 2016

No abstract provided.

The Writing Attitude Scale For Teachers (Wast), Anna H. Hall

Publications

This study examines the psychometric properties of the Writing Attitude Scale for Teachers (WAST) using scores of preservice teachers to gather evidence of content, internal structure, response processes, reliability/precision, and correlations with external variables. Four contending models were compared using CFA, but the unidimensional model was championed. The WAST was further refined using IRT to 10-items and shown to have high precision across most of the latent continuum. The WAST was shown to have incremental evidence relative to the Writing Apprehension Test when predicting attitudes towards attending a professional development workshop on writing instruction and time devoted to writing instruction.

Ion Transport Through Macrocapillaries – Oscillations Due To Charge Patch Formation, Dhruva Kulkarni, L.A.M. Lyle, Chad E. Sosolik

Publications

We present results on ion transport through large bore capillaries (macrocapillaries) that probe both the geometric and ion-guided aspects of this ion delivery mechanism. We have demonstrated that guiding in macrocapillaries exhibits position- and angle-dependent transmission properties which are directly related to the capillary material (either metal or insulator) and geometry. Specifically, we have passed 1 keV Rb⁺ ions through glass and metal macrocapillaries, and have observed oscillations for the transmitted ion current passing through the insulating capillaries. Straightforward calculations show that these oscillations can be attributed to beam deflections from charge patches that form on the interior walls …

Relaxations And Discretizations For The Pooling Problem, Akshay Gupte, Shabbir Ahmed, Santanu S. Dey, Myun Seok Cheon

Publications

The pooling problem is a folklore NP-hard global optimization problem that finds applications in industries such as petrochemical refining, wastewater treatment and mining. This paper assimilates the vast literature on this problem that is dispersed over different areas and gives new insights on prevalent techniques. We also present new ideas for computing dual bounds on the global optimum by solving high-dimensional linear programs. Finally, we propose discretization methods for inner approximating the feasible region and obtaining good primal bounds. Valid inequalities are derived for the discretized models, which are formulated as mixed integer linear programs. The strength of our relaxations …

What Moser Could Have Asked: Counting Hamilton Cycles In Tournaments, Neil J. Calkin, Beth Novick, Hayato Ushijima-Mwesigwa

Publications

Moser asked for a construction of explicit tournaments on n vertices having at least Hamilton cycles. We show that he could have asked rather more.

A Ph Sensor For Non-Invasive In Vivo Detection And Imaging Of Implant Associated Infection, Unaiza Uzair, Donald Benza, Fenglin Wang, Yash Raval, Tzuen-Rong J. Tzeng, Jeffrey N. Anker

Chemistry Annual Research Symposium

We develop a pH sensor based on use of X-ray Excited Luminescence Chemical Imaging (XELCI) to non-invasively detect and image changes in pH of a surface with high spatial and pH resolution while minimizing tissue scattering effects. Diagnosis and treatment of infections associated with implanted medical devices is a challenge, as clinical symptoms of implant associated infection are often delayed and can sometimes be completely absent till infection reaches a later stage. Early diagnosis of implant associated infection and non-invasive continuous monitoring of infection to evaluate eradication and success of treatment has not been established yet. Treatment of implant infection …

Hydrothermal Single Crystal Growth And Characterization Of Novel Rare Earth Niobates And Tantalates: Lnnbo4 (Ln = La-Lu , Y), La2tao5(Oh) And Ln3ta2o9(Oh), Liurukara D. Sanjeewa, Kyle Fulle, Colin D. Mcmillen, Joseph W. Kolis

Chemistry Annual Research Symposium

Rare-earth niobates and tantalates are refractory materials that have been exploited in applications involving ion conductivity, photo-catalysis, and luminescence, both in doped and un-doped forms.

In general, refractory oxides have high melting points therefore synthesis of single crystals are more challenging. For example LnNbO4 can be grown readily by melt techniques such as Czochralski pulling ~1300 ˚C. However during the cooling crystal quality degraded resulting low quality crystals therefore high temperature melting techniques are not suitable for bulk single crystals growth.

Stability Of Copper(Ii) Complexes Of Sulfur And Selenium Antioxidants, Jaime M. Murphy, Brian A. Powell, Julia Brumaghim

Chemistry Annual Research Symposium

We focused on determining the stability constants for Cu(II) binding of sulfur and selenium antioxidants in aqueous conditions by potentiometric or spectrophotometric determination. Correlations of stability constant and antioxidant capability, as previously determined by gel electrophoresis, are examined, as well as the likelihood of each complex forming in vivo.

Understanding The Role Of Nadh In Cellular Fe2+ Generation Of Hydroxyl Radical And The Effects Of Polyphenol Antioxidants, Craig Goodman, Julia L. Brumaghim

Chemistry Annual Research Symposium

Structurally similar polyphenols have opposite effects on rates of Fe3+ reduction by NADH. In future work, we anticipate exploring several avenues:

What is the role of autoxidation? UV-vis kinetic experiments in an air-free atmosphere should reveal if MEGA is increasing the pool of reducible Fe3+.

What occurs in the presence of H2O2 and/or increased levels of NADH? Mimicking the environment of a stressed cell should yield interesting information about antioxidant activity if the rates change significantly.

Short F···F And F(Cl)···O Contacts In Fluoroorganic Crystals, And Short Ag···Ag And Ag···O Contacts In Silver Polyfluoroacetate Salts, Xiaolin Liu, Andrej V. Matsnev, Steven P. Belina, Colin D. Mcmillen, Joseph S. Thrasher

Chemistry Annual Research Symposium

The compound 2,2,5,5-tetrafluoro-2,5-dihydrofuran (1) [1] has been synthesized as a candidate monomer for synthesizing amorphous fluoropolymers in our research laboratory. Meanwhile, several crystal structures of products resulting from either new or existing chemistry of this cyclic ether have been solved and will be reported herein. The structures of the tricyclic ether 4 [2], resulting from the photodimerization of 1 in the presence of dry air, as well as perfluorooxodiacetic acid, resulting from the ring-opening oxidation of 1 [3], show a variety of short H···F, F···F, and O···F interactions. The crystal structure of 1,1,2,2,3,3,4,4-octafluorobutane-1,4-disulfonyl dichloride (ODD) reveals not only short F···F …

Surface Functionalized Nylon Capillary-Channeled Polymer (C-Cp) Fibers For Protein Ion-Exchange Separations, Liuwei Jiang, R. Kenneth Marcus

Chemistry Annual Research Symposium

Native nylon C-CP fibers have a very low density (~20 μmol g-1) of carboxylic acid groups that limits its performance on protein separations. To overcome this challenge, surface modification was done on native nylon fibers by grafting monomer ligands (acrylics) via microwave-assisted free radical polymerization.