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Title: MODELING SATELLITE FORMATIONS IN THE PRESENCE OF PERTURBATIONS.
Creator: Cannaday, Robert, Johnson, Roger, University of Central Florida
Abstract / Description: The potential benefits of autonomous satellite formation flying in such areas as high- resolution remote sensing, and sparse aperture radar, has stimulated interest in modeling the satellite environment for feasibility and simulation studies to help explore and define the technical challenges that must be solved in order to achieve successful autonomous satellite formations. The purpose of this paper is to develop and describe a numerical simulation of the orbital environment including...
Show moreThe potential benefits of autonomous satellite formation flying in such areas as high- resolution remote sensing, and sparse aperture radar, has stimulated interest in modeling the satellite environment for feasibility and simulation studies to help explore and define the technical challenges that must be solved in order to achieve successful autonomous satellite formations. The purpose of this paper is to develop and describe a numerical simulation of the orbital environment including central force field perturbations and atmospheric drag effects which will be a useful analytical tool for investigating issues relating to maintaining satellite formations in low-earth-orbit. Many of the studies done in this area confine their research to circular orbits, with and without perturbation effects. This study will investigate apply orbital dynamic equations to the problem of maintaining satellite formations in both circular and elliptical orbits, with and without the presence of J2 gravity perturbation effects and atmospheric drag. This effort is primarily focused on modeling the orbital mechanics of one and two satellites in the presence of J2 and drag perturbations This effort is being performed as part of a multi-disciplined University of Central Florida KnightSat project, sponsored by the Air Force, to develop a two-satellite formation in the nanosatellite class, for investigating issues related to using formation satellites for remote earth sensing, to develop three-dimensional mapping.
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Date Issued: 2005
Identifier: CFE0000898, ucf:46639
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000898

Title: PARTI: EVALUATION OF RUSSIAN SYNTHETIC COMPOUNDS AS A POTENTIAL SOURCE OF NEW DRUG LEADS AGAINST BREAST AND COLON CANCER. PARTII: ISOLATION OF &ACIRC;-AMYRIN FORMATE FROM EUCALYPTUS VIMINALIS LABILL AND INVESTIGATION OF ITS COLON CANCER ACTIVITY.
Creator: Cohanoschi, Mihaela, Miles, Howard, University of Central Florida
Abstract / Description: Although modern medicine made great steps toward curing most diseases considered deadliest, yet cancer remains one of the major public health problems. The first part of this thesis investigates a new source of selective compounds that are potential candidates against cancer. Fifteen Russian compounds were tested in order to establish their efficiency against two types of cancer: human breast SK-Br-3 and colorectal carcinoma HT-29. The bioassay results show that seven of the new synthetic...
Show moreAlthough modern medicine made great steps toward curing most diseases considered deadliest, yet cancer remains one of the major public health problems. The first part of this thesis investigates a new source of selective compounds that are potential candidates against cancer. Fifteen Russian compounds were tested in order to establish their efficiency against two types of cancer: human breast SK-Br-3 and colorectal carcinoma HT-29. The bioassay results show that seven of the new synthetic Russian compounds can be considered new drug leads, based upon their low toxicity and efficacy in slowing the growth of human breast cancer and colon cancer cells. The goal of the second part of the thesis was to isolate pure compounds that inhibit the growth of cancer cells from the methylene chloride extract of Eucalyptus viminalis Labill. This plant was selected for investigations since a preliminary screening of plants from Russia indicated that had activity against cancer. The result of this work was the isolation of a pure compound which has been analyzed using different spectroscopic techniques such as MS, HPLC, 1H-NMR, DEPT, 13C-NMR. The extracted compound was â-amyrin formate, which was previously reported by Malhotra,[49] from Canarium strictum Gum in 1987. Also, the bioassay results indicated that â-amyrin formate might be considered a possible drug lead against colon cancer and can be recommended for further investigations. This is the first report of isolation of â-amyrin formate from Eucalyptus viminalis Labill and the first test of the activity of this compound against colon cancer.
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Date Issued: 2004
Identifier: CFE0000216, ucf:46274
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000216

Title: COALITION FORMATION AND TEAMWORK IN EMBODIED AGENTS.
Creator: Khan, Majid, Blni, Ladislau, University of Central Florida
Abstract / Description: Embodied agents are agents acting in the physical world, such as persons, robots, unmanned air or ground vehicles and so on. These types of agents are subject to spatio-temporal constraints, which do not exist for agents acting in a virtual environment. The movement of embodied agents is limited by obstacles and maximum velocity, while their communication is limited by the transmission range of their wireless devices. This dissertation presents contributions to the techniques of coalition...
Show moreEmbodied agents are agents acting in the physical world, such as persons, robots, unmanned air or ground vehicles and so on. These types of agents are subject to spatio-temporal constraints, which do not exist for agents acting in a virtual environment. The movement of embodied agents is limited by obstacles and maximum velocity, while their communication is limited by the transmission range of their wireless devices. This dissertation presents contributions to the techniques of coalition formation and teamwork coordination for embodied agents. We considered embodied agents in three different settings, each of them representative of a class of practical applications. First, we study coalition formation in the one dimensional world of vehicles driving on a highway. We assume that vehicles can communicate over short distances and carry agents which can advise the driver on convoy formation decisions. We introduce techniques which allow vehicles to influence the speed of the convoys, and show that this yields convoys which have a higher utility for the participating vehicles. Second, we address the problem of coalition formation in the two dimensional world. The application we consider is a disaster response scenario. The agents are forming coalitions through a multi-issue negotiation with spatio-temporal components where the coalitions maintain a set of commitments towards participating agents. Finally, we discuss a scenario where embodied agents form coalitions to optimally address dynamic, non-deterministic, spatio-temporal tasks. The application we consider is firefighters acting in a disaster struck city.
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Date Issued: 2007
Identifier: CFE0001843, ucf:47334
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001843

Title: POSITIVE OUTCOMES OF DIVORCE: A MULTI-METHOD STUDY ON THE EFFECTS OF PARENTAL DIVORCE ON CHILDREN.
Creator: Mohi, Grant, Grauerholz, Elizabeth, University of Central Florida
Abstract / Description: A great deal of the existing literature on parental divorce focuses on the negative influences it has on children and young adults in regards to such areas as their relationships (romantic and familial) and their academic standing. The implications of such research are that parental divorce will always bring harm to families and, consequentially, should be avoided for the sake of the children's wellbeing. What is often missing from this research is a focus on the potential positive outcomes...
Show moreA great deal of the existing literature on parental divorce focuses on the negative influences it has on children and young adults in regards to such areas as their relationships (romantic and familial) and their academic standing. The implications of such research are that parental divorce will always bring harm to families and, consequentially, should be avoided for the sake of the children's wellbeing. What is often missing from this research is a focus on the potential positive outcomes of parental divorce. The intent of this thesis is to explore the effects of parental divorce on young adults' ability to form and maintain romantic relationships, focusing on the positive outcomes of parental divorce on young adults and seeking to answer the question of whether or not young adults can actually benefit from their parents' divorce. By surveying a sample of 233 students from divorced and intact families from a large university on their experiences with parental divorce and/or romantic relationships, in conjunction with face to face interviews, the current study provides a deeper insight into the social factors that help define divorce as positive and explores the effects of family structure, gender of child, economic situation, and pre-existing parental conflict on young adults of divorced parents. Findings suggest that these young adults do experience positive outcomes after the divorce and that these outcomes are dependent on a variety of familial and social factors that shape the divorce experience.
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Date Issued: 2014
Identifier: CFH0004550, ucf:45226
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0004550

Title: REACTIVE CONTROL OF AUTONOMOUS DYNAMICAL SYSTEMS.
Creator: Chunyu, Jiangmin, Qu, Zhihua, University of Central Florida
Abstract / Description: This thesis mainly consists of five independent papers concerning the reactive control design of autonomous mobile robots in the context of target tracking and cooperative formation keeping with obstacle avoidance in the static/dynamic environment. Technical contents of this thesis are divided into three parts. The first part consists of the first two papers, which consider the target-tracking and obstacle avoidance in the static environment. Especially, in the static environment, a...
Show moreThis thesis mainly consists of five independent papers concerning the reactive control design of autonomous mobile robots in the context of target tracking and cooperative formation keeping with obstacle avoidance in the static/dynamic environment. Technical contents of this thesis are divided into three parts. The first part consists of the first two papers, which consider the target-tracking and obstacle avoidance in the static environment. Especially, in the static environment, a fundamental issue of reactive control design is the local minima problem (LMP) inherent in the potential field methods (PFMs). Through introducing a state-dependent planned goal, the first paper proposes a switching control strategy to tackle this problem. The control law for the planned goal is presented. When trapped into local minima, the robot can escape from local minima by following the planned goal. The proposed control law also takes into account the presence of possible saturation constraints. In addition, a time-varying continuous control law is proposed in the second paper to tackle this problem. Challenges of finding continuous control solutions of LMP are discussed and explicit design strategies are then proposed. The second part of this thesis deals with target-tracking and obstacle avoidance in the dynamic environment. In the third paper, a reactive control design is presented for Omni-directional mobile robots with limited sensor range to track targets while avoiding static and moving obstacles in a dynamically evolving environment. Towards this end, a multi-objective control problem is formulated and control is synthesized by generating a potential field force for each objective and combining them through analysis and design. Different from standard potential field methods, the composite potential field described in this paper is time-varying and planned to account for moving obstacles and vehicle motion. In order to accommodate a larger class of mobile robots, the fourth paper proposes a reactive control design for unicycle-type mobile robots. With the relative motion among the mobile robot, targets, and obstacles being formulated in polar coordinates, kinematic control laws achieving target-tracking and obstacle avoidance are synthesized using Lyapunov based technique, and more importantly, the proposed control laws also take into account possible kinematic control saturation constraints. The third part of this thesis investigates the cooperative formation control with collision avoidance. In the fifth paper, firstly, the target tracking and collision avoidance problem for a single agent is studied. Instead of directly extending the single agent controls to the multi-agents case, the single agent controls are incorporated with an existing cooperative control design. The proposed decentralized control is reactive, considers the formation feedback and changes in the communication networks. The proposed control is based on a potential field method; its inherent oscillation problem is also studied to improve group transient performance.
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Date Issued: 2010
Identifier: CFE0003421, ucf:48384
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003421

Title: Atomic-scale simulation of physical and chemical processes during space weathering and planet formation.
Creator: Quadery, Abrar, Schelling, Patrick, Britt, Daniel, Peale, Robert, Kara, Abdelkader, Sohn, Yongho, University of Central Florida
Abstract / Description: We investigate the mechanisms of space weathering and dust grain collisions, two topics of interests from planetary sciences, using atomic-scale simulations. Space weathering is the change in chemical and physical properties of minerals exposed to solar radiation and micrometeorite bombardment on surfaces of airless planetary bodies like the Moon and asteroids. An understanding of the connection between the surface evolution of the minerals and the underlying thermodynamic and kinetic factors...
Show moreWe investigate the mechanisms of space weathering and dust grain collisions, two topics of interests from planetary sciences, using atomic-scale simulations. Space weathering is the change in chemical and physical properties of minerals exposed to solar radiation and micrometeorite bombardment on surfaces of airless planetary bodies like the Moon and asteroids. An understanding of the connection between the surface evolution of the minerals and the underlying thermodynamic and kinetic factors is still missing. We address this issue and determine the time evolution of Frenkel defects in the silicate minerals olivine ((Mg,Fe)$_2$SiO$_4$) and orthopyroxene ((Mg,Fe)SiO$_3$) using molecular dynamics with a pair potential. Defect diffusion and clustering are observed in both the minerals. Cation diffusion occurs more readily in olivine than in orthopyroxene and leads to faster annealing in the former. In orthopyroxene, diffusion of anion defects, especially oxygen interstitials, occurs more rapidly and also exhibits anisotropy, which hinders the annealing process. This difference in defect evolution may explain the experimental observation that surface modifications due to irradiation is more pronounced in orthopyroxene than in olivine. Dust grain collision is the dominant process in the initial stage of planet formation, however, the mechanisms by which dust grains grow to larger aggregates and eventually to kilometer sized planetesimal is still not understood. We explore the role of surface chemistry in energy dissipation and grain adhesion during collision of amorphous silica (SiO$_2$) nanograins using molecular dynamics with a reactive potential, namely ReaxFF. We found nonhydroxylated amorphous silica nanoparticles stick with higher probability than their hydroxylated counterpart. This difference is attributed to the preponderance of unsatisfied dangling bonds on the dry silicate surface which facilitate bond formation during collision, and thereby provide a mechanism for energy dissipation. The speed below which sticking occurs in the dry nanograins is much higher than that found in Earth-based experiments, which suggests any experimental study of dust grain collision should take into account of the chemical environment. We probe into the nanograin collisions further and carry out atomistic simulatons of collisions of molten silica nanograins. We observed in the molten state, amorphous silica is more sticky than it is in the solid phase. This happens due to increased viscoelastic energy dissipation. The result may explain how rocky planets originated from the inner rings of the protoplanetay disks where temperatures were as high as $\sim$ 2000 K. In order to increase the range of materials that could be simulated with ReaxFF potential, and also to examine the different oxidation states of iron associated with nanophase iron formation during space weathering, we made attempt to develop ReaxFF potential for fayalite (Fe$_2$SiO$_4$). We found out fundamental limitations of ReaxFF model to describe three-component minerals. However, during the fitting process we developed a model for iron silicide (FeSi), and made attempt to improve the silica model to obtain better elastic properties. We report here the fitting processes and the observed limitations of ReaxFF model.
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Date Issued: 2017
Identifier: CFE0006907, ucf:51691
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006907

Title: AUTONOMOUS CONTROLS ALGORITHMFOR FORMATION FLYING OF SATELLITES.
Creator: Santiago, Luis, Johnson, Roger, University of Central Florida
Abstract / Description: This document describes the design and analysis of the Navigation, Guidance and Control System for the KnightSat project. The purpose for the project is to test and demonstrate new technologies the Air Force would be interested in for research and development. The primary mission of KnightSat is to show how a constellation of satellites can maintain relative position with each other autonomously using the Microwave Electro Thermal (MET) thruster. The secondary mission is to use multiple...
Show moreThis document describes the design and analysis of the Navigation, Guidance and Control System for the KnightSat project. The purpose for the project is to test and demonstrate new technologies the Air Force would be interested in for research and development. The primary mission of KnightSat is to show how a constellation of satellites can maintain relative position with each other autonomously using the Microwave Electro Thermal (MET) thruster. The secondary mission is to use multiple satellite imagery to obtain 3 dimensional stereo photographs of observable terrain. Formation flying itself has many possible uses for future applications. Selected missions that require imaging or data collection can be more economically accomplished using smaller multiple satellites. The MET thruster is a very efficient, but low thrust alternative that can provide thrust for a very long time, hence provide the low thrust necessary to maintain the satellites at a constant separation. The challenge is to design a working control algorithm to provide the desired output data to be used to command the MET thrusters. The satellites are to maintain a constant relative distance from each other, and use the least amount of fuel possible. If one satellite runs out of fuel before the other, it would render the constellation less useful or useless. Hence, the satellites must use the same amount of fuel in order to maintain an optimal operational duration on orbit.
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Date Issued: 2006
Identifier: CFE0001171, ucf:46854
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001171

Title: SEARCH, CHARACTERIZATION, AND PROPERTIES OF BROWN DWARFS.
Creator: Tata, Ramarao, Martin, Eduardo, University of Central Florida
Abstract / Description: Brown dwarfs (BD) were mere theoretical astrophysical objects for more than three decades (Kumar (1962)) till their first observational detection in 1995 (Rebolo et al. (1995), Nakajima et al. (1995)). These objects are intermediate in mass between stars and planets. Since their observational discovery these objects have been studied thoroughly and holistically.Various methods for searching and characterizing these objects in different regions of the sky have been put forward and tested with...
Show moreBrown dwarfs (BD) were mere theoretical astrophysical objects for more than three decades (Kumar (1962)) till their first observational detection in 1995 (Rebolo et al. (1995), Nakajima et al. (1995)). These objects are intermediate in mass between stars and planets. Since their observational discovery these objects have been studied thoroughly and holistically.Various methods for searching and characterizing these objects in different regions of the sky have been put forward and tested with great success. Theoretical models describing their physical, atmospheric and chemical processes and properties have been proposed and have been validated with a large number of observational results. The work presented in this dissertation is a compilation of synoptic studies of ultracool dwarfs(UDs. • A search for wide binaries around solar type stars in upper scorpio OB association(Upper Sco) do indicate (the survey is not yet complete) a deficit of BD binaries at these large separations (< 5AU). • Twenty six new UDs were discovered at low galactic latitudes in our survey from archival data and a novel technique using reduced proper motion. • Six field UDs were discovered by spectroscopic follow-up of the candidates selected from a deep survey. • Optical interferometry was used to independently determine the orbit of the companion of HD33636 which was initially determined using Hubble Space Telescope(HST)astrometry and radial velocity found. Some inconsistency in the HST determined orbit and mass. • Optical linear polarization in UDs was used to investigate the dust propertied in their atmospheres. A trend in polarization as predicted by theoretical models was validated, and atmospheric dust grain sizes and projected rotational velocities for these objects were estimated. Comprehensive studies of UDs are proving to be crucial not only in our understanding of UDs but also for star and planet formation as brown dwarfs represent their lower and upper mass boundaries, respectively.
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Date Issued: 2009
Identifier: CFE0002943, ucf:47952
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002943

Title: First Principles Studies of Pattern Formations and Reactions on Catalyst Surfaces.
Creator: Le, Duy, Rahman, Talat, Roldan Cuenya, Beatriz, Schelling, Patrick, Sohn, Yongho, University of Central Florida
Abstract / Description: This dissertation undertakes theoretical research into the adsorption, pattern formation, and reactions of atoms, molecules, and layered materials on catalyst surfaces. These investigations are carried out from first-principles calculations of electronic and geometric structures using density functional theory (DFT) for predictions and simulations at the atomic scale. The results should be useful for further study of the catalytic activities of materials and for engineering functional...
Show moreThis dissertation undertakes theoretical research into the adsorption, pattern formation, and reactions of atoms, molecules, and layered materials on catalyst surfaces. These investigations are carried out from first-principles calculations of electronic and geometric structures using density functional theory (DFT) for predictions and simulations at the atomic scale. The results should be useful for further study of the catalytic activities of materials and for engineering functional nanostructures.The first part of the dissertation focuses on systematic first-principles simulations of the energetic pathways of CO oxidation on the Cu2O(100) surface. These simulations show CO to oxidize spontaneously on the O-terminated Cu2O(100) surface by consuming surface oxygen atoms. The O-vacancy on Cu2O(100) then is subsequently healed by dissociative adsorption of atmospheric O2 molecules.The second part discusses the pattern formation of hydrogen on two and three layers of Co film grown on the Cu(111) surface. It is found that increasing the pressure of H2 changes the hydrogen structure from 2H-(2 x 2) to H-p(1 x 1) through an intermediate structure of 6H-(3 x 3).The third part compares the results of different ways of introducing van der Waals (vdW) interactions into DFT simulations of the adsorption and pattern formation of various molecules on certain substrates. Examinations of the physisorption of five nucleobases on graphene and of n-alkane on Pt(111) demonstrate the importance of taking vdW interactions into account, and of doing so in a way that is best suited to the particular system in question. More importantly, as the adsorption of 1,4 diaminebenzene molecules on Au(111) shows inclusion of vdW interactions is crucial for accurate simulation of the pattern formation.The final part carries out first-principles calculations of the geometric and electronic structure of the Moire pattern of a single layer of Molybdenum disulfide (MoS2) on Cu(111). The results reveal three possible stacking types. They also demonstrate that the MoS2 layer to be chemisorbed, albeit weakly, and that, while Cu surface atoms are vertically disordered, the layer itself is not strongly buckled.
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Date Issued: 2012
Identifier: CFE0004224, ucf:48991
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004224

Title: Formative Assessment: Benefit For All.
Creator: Wallace, William, Dixon, Juli, Dieker, Lisa, Andreasen, Janet, University of Central Florida
Abstract / Description: This study investigated how formative assessment implemented in a fifth grade mathematics classroom with a student response system and a student self-evaluative tool affected student self-assessment. Data were collected through individual student and focus group interviews, self-assessment sheets, and teacher reflections.Formative assessment is a low stakes classroom assessment that is an assessment for learning. This study used a student response system to convey feedback from the formative...
Show moreThis study investigated how formative assessment implemented in a fifth grade mathematics classroom with a student response system and a student self-evaluative tool affected student self-assessment. Data were collected through individual student and focus group interviews, self-assessment sheets, and teacher reflections.Formative assessment is a low stakes classroom assessment that is an assessment for learning. This study used a student response system to convey feedback from the formative assessment to both students and teacher during instruction. The student self-assessment sheet was implemented to provide a more dynamic level of feedback for students than what could be provided through the student response system alone.
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Date Issued: 2013
Identifier: CFE0004955, ucf:49584
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004955

Title: Probing Space: Formative Assessment in a Middle School Inquiry-Based Science Classroom.
Creator: Anderson, Clinton, Jeanpierre, Bobby, Gresham, Regina, Everett, Robert, University of Central Florida
Abstract / Description: This action research thesis was performed to explore the research questions: How did the use of formative assessment affect student performance data in understanding the concepts of the Sun-Earth-Moon system?, How did the use of learning scales as formative techniques impact student self-assessment of their knowledge of the Sun-Earth-Moon system?, How did the implementation of formative assessment techniques affect student discourse on the topic of the Sun-Earth-Moon system? Formative...
Show moreThis action research thesis was performed to explore the research questions: How did the use of formative assessment affect student performance data in understanding the concepts of the Sun-Earth-Moon system?, How did the use of learning scales as formative techniques impact student self-assessment of their knowledge of the Sun-Earth-Moon system?, How did the implementation of formative assessment techniques affect student discourse on the topic of the Sun-Earth-Moon system? Formative assessment techniques including (")talk-friendly(") probes, sticky bars, and agree-disagree statements were used in the classroom to expose gaps in knowledge, to facilitate discourse, and promote self-assessment. A triangulation of data included a district-provided pre/post-test, teacher observation, written and oral student responses of formative assessment, self-assessment, discourse, and student self-assessment on a learning goal tracker. Data gathered from student responses to formative assessment techniques given during discourse, lab experiences, in written responses, and from the student learning scale tracker were analyzed to expose misconceptions and gaps in knowledge and guide classroom instruction. Data showed that student performance data improved overall and students narrowed gaps in knowledge of the Sun-Earth-Moon system. Improvement in student participation and skill of discourse was evident; however students needed more practice developing written explanations for phenomenon within the Sun-Earth-Moon system. Through the use of self-assessments students showed improvement in ability to self-assess and realized gained knowledge toward their learning goal.
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Date Issued: 2012
Identifier: CFE0004285, ucf:49527
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004285

Title: Provider Recommendation of HPV Vaccination: Bridging the Intention-Behavior Gap.
Creator: Landis, Erica, Neuberger, Lindsay, Sandoval, Jennifer, Miller, Ann, University of Central Florida
Abstract / Description: The present study, guided by preproduction formative research principles, employed in-depth interviews and a brief survey with pediatric healthcare providers (N=15) to investigate the consistency between behavioral intention to strongly recommend the HPV vaccine, and implementation of the actual behavior. Specifically, the Integrative Model of Behavioral Prediction (IMBP) was used as a framework to examine the impact of skills and environmental constraints on that behavioral intention...
Show moreThe present study, guided by preproduction formative research principles, employed in-depth interviews and a brief survey with pediatric healthcare providers (N=15) to investigate the consistency between behavioral intention to strongly recommend the HPV vaccine, and implementation of the actual behavior. Specifically, the Integrative Model of Behavioral Prediction (IMBP) was used as a framework to examine the impact of skills and environmental constraints on that behavioral intention-behavioral performance relationship. Results suggest providers intend to strongly recommend the HPV vaccine at a high level, but actually recommend the vaccine with a slightly lesser frequency. A thematic analysis of interview transcripts yielded a list of skills (e.g., tact, cultural competence) and environmental constraints (e.g., a lack of policy or school entry requirement, limited time designated for each patient) that contribute to that consistency gap. Additionally, healthcare providers indicated several preferences on training design (e.g., Continuing Medical Education course, delivered by medical and communication professionals) that could be used to inform future message construction. Suggestions for overcoming the environmental constraints reported by providers are presented, and implications for incorporating the emergent skills and preferences into training as a novel strategy for improving provider communication about the HPV vaccine outlined.
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Date Issued: 2016
Identifier: CFE0006132, ucf:51162
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006132

Title: Prehabilitation (Prehab): Prevention in Motion.
Creator: Russell, Billie, Sole, Mary Lou, Chase, Susan, Damato-Kubiet, Leslee, Gammonley, Denise, University of Central Florida
Abstract / Description: ABSTRACTCardiovascular disease is the leading cause of death for U.S. adults. It adds greater than $100 billion to U.S. health care costs annually. Rates of morbidity, mortality, and economic burden of the disease could be dramatically reduced with improvements in sedentary behaviors among adults with coronary artery disease (CAD). A regular commitment to moderate physical activity can reduce ischemic heart events up to 50%. Although the benefits of physical activity are well-known for...
Show moreABSTRACTCardiovascular disease is the leading cause of death for U.S. adults. It adds greater than $100 billion to U.S. health care costs annually. Rates of morbidity, mortality, and economic burden of the disease could be dramatically reduced with improvements in sedentary behaviors among adults with coronary artery disease (CAD). A regular commitment to moderate physical activity can reduce ischemic heart events up to 50%. Although the benefits of physical activity are well-known for individuals with coronary artery disease, an estimated 70% of this population remains relatively sedentary. Hospital-based cardiac rehabilitation programs are the single secondary prevention option offered to improve physical activity habits in persons with CAD. Although effective, cardiac rehabilitation is inaccessible for the majority of CAD sufferers and is offered only after an acute cardiac event. Different from rehabilitation, prehabilitation (prehab) programs use physical activity as a means to deter a worsening condition or prevent injury before an acute event occurs. These programs have proved successful in other areas of medicine but there are currently no such secondary prevention programs available for stable persons with CAD in the U.S. A home-based prehab program could help adults with CAD establish improved physical activity habits and circumvent many of the barriers associated with admission and attendance of a hospital-based cardiac rehabilitation program. Researchers have indicated that self-efficacy is key to initiation and sustentation of a regular physical activity habit, regardless of the physical activity program that one attends. These habits are more likely to last when participants receive self-efficacy based support for an average of 66 days. The purpose of this study was to determine if a nurse-practitioner-led, home-based, prehab program could assist adults with CAD to improve and maintain increased physical activity habits and levels of self-efficacy for physical activity. The five primary facilitators of self-efficacy were used to devise a 10-week prehab program. A convenience sample of 54 adults with diagnosed CAD was recruited from cardiology practices in St. Johns County, Florida. The research population was 68.5% (n=37) male, 88.9% (n=48) Caucasian, and 74% (n=40) married with a mean age of 68.57 years. Participants attended a 90-minute prehab class which offered health education and group discussion of barriers and goals for regular physical activity. Following the class, participants were contacted weekly for 10-weeks to discuss goal progress, assist in circumventing barriers, and revise physical activity goals as needed. After the 10-week call period, participants were contacted 30-days later to assess for physical activity habit maintenance and any sustained benefit in self-efficacy for physical activity. Self-efficacy for exercise was measured before the prehab class, after the prehab class, and after the 10-week intervention period using the Short Self-Efficacy Expectations scale (SSEE), Multidimensional Outcomes Expectations for Exercise Scale (MOEES), and the Barriers Self-Efficacy Scale (BARSE). All baseline measures of self-efficacy (MOEES, BARSE, SSEE) improved significantly immediately following the prehab class. Baseline physical outcome expectations of the MOEES (m=21.87, sd=4.67), self-evaluative outcome expectations of the MOEES (m=16.70, sd=4.15) and SSEE (m=12.75, sd=4.02) remained significantly improved after the 10-week intervention period (p(<).05). At the 10-week assessment, mean significant self-efficacy scores were 24.39 (sd=1.26, p(<).01) for physical outcome expectations, 18.39 (sd=2.27, p(<).02) for self-evaluative outcome expectations, and 15.06, (sd=3.25, p(<).001) for SSEE. The SSEE was reassessed 30-days after the study and remained significantly improved compared to baseline (m=15.65, sd=3.42, p(<).01). Qualitative data collection coincided with the quantitative self-efficacy findings. Participants reported satisfaction with physical activity goal attainment and increased confidence to continue with a regular physical activity plan. The Godin Leisure-Time Exercise Questionnaire (GLTEQ) was used to assess activity levels at baseline, during each weekly phone call, at the end of 10-weeks, and 30-days after the study. Repeated-measures ANOVA (F (2,90) = 21.86, p(<).001) revealed that participant's baseline physical activity volume measured by GLTEQ (m=18.39, sd= 16.93) improved significantly after 10 weeks in the prehab study (m=41.10, sd=24.11, p(<).001) and remained significantly improved when re-measured 30-days after the study (m=39.02, sd=21.87, p(<).001). Qualitative data concurred with quantitative data with participants reporting physical activity habit formation and maintenance of self-regulatory skills. Qualitative data also demonstrated that participants in prehab experienced very similar facilitators and barriers compared to other adults with CAD attempting an exercise program. In summary, the prehab study findings coincided with other research findings in this area. Self-efficacy based support can assist individuals with CAD to improve and maintain physical activity habits. The ease of the intervention likely contributed to lower cost and attrition rates (7%) compared to hospital-based cardiac rehabilitation programs. Although more research is needed, study findings suggest that a nurse-practitioner-led, home-based program could be a viable secondary prevention strategy for stable adults with CAD. This should be considered for the future given that even modest improvements in physical activity can substantially reduce all-cause mortality in this population.
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Date Issued: 2016
Identifier: CFE0006384, ucf:51530
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006384

Title: Planning and Control of Swarm Motion as Continua.
Creator: Rastgoftar, Hossein, Jayasuriya, Suhada, Das, Tuhin, Xu, Chengying, Qu, Zhihua, Simaan, Marwan, University of Central Florida
Abstract / Description: In this thesis, new algorithms for formation control of multi agent systems (MAS) based on continuum mechanics principles will be investigated. For this purpose agents of the MAS are treated as particles in a continuum, evolving in an n-D space, whose desired configuration is required to satisfy an admissible deformation function. Considered is a specific class of mappings that is called homogenous where the Jacobian of the mapping is only a function of time and is not spatially varying. The...
Show moreIn this thesis, new algorithms for formation control of multi agent systems (MAS) based on continuum mechanics principles will be investigated. For this purpose agents of the MAS are treated as particles in a continuum, evolving in an n-D space, whose desired configuration is required to satisfy an admissible deformation function. Considered is a specific class of mappings that is called homogenous where the Jacobian of the mapping is only a function of time and is not spatially varying. The primary objectives of this thesis are to develop the necessary theory and its validation via simulation on a mobile-agent based swarm test bed that includes two primary tasks: 1) homogenous transformation of MAS and 2) deployment of a random distribution of agents on to a desired configuration. Developed will be a framework based on homogenous transformations for the evolution of a MAS in an n-D space (n=1, 2, and 3), under two scenarios: 1) no inter-agent communication (predefined motion plan); and 2) local inter-agent communication. Additionally, homogenous transformations based on communication protocols will be used to deploy an arbitrary distribution of a MAS on to a desired curve. Homogenous transformation with no communication: A homogenous transformation of a MAS, evolving in an R^n space, under zero inter agent communication is first considered. Here the homogenous mapping, is characterized by an n x n Jacobian matrix Q(t) and an n x 1 rigid body displacement vector D(t), that are based on positions of n+1 agents of the MAS, called leader agents. The designed Jacobian Q(t) and rigid body displacement vector D(t) are passed onto rest of the agents of the MAS, called followers, who will then use that information to update their positions under a pre-defined motion plan. Consequently, the motion of MAS will evolve as a homogenous transformation of the initial configuration without explicit communication among agents. Homogenous Transformation under Local Communication: We develop a framework for homogenous transformation of MAS, evolving in R^n, under a local inter agent communication topology. Here we assume that some agents are the leaders, that are transformed homogenously in an n-D space. In addition, every follower agent of the MAS communicates with some local agents to update its position, in order to grasp the homogenous mapping that is prescribed by the leader agents. We show that some distance ratios that are assigned based on initial formation, if preserved, lead to asymptotic convergence of the initial formation to a final formation under a homogenous mapping.Deployment of a Random Distribution on a Desired Manifold: Deployment of agents of a MAS, moving in a plane, on to a desired curve, is a task that is considered as an application of the proposed approach. In particular, a 2-D MAS evolution problem is considered as two 1-D MAS evolution problems, where x or y coordinates of the position of all agents are modeled as points confined to move on a straight line. Then, for every coordinate of MAS evolution, bulk motion is controlled by two agents considered leaders that move independently, with rest of the follower agents motions evolving through each follower agent communicating with two adjacent agents.
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Date Issued: 2013
Identifier: CFE0004915, ucf:49640
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004915

Title: Numerical Simulations for the Flow of Rocket Exhaust Through a Granular Medium.
Creator: Kraakmo, Kristina, Moore, Brian, Brennan, Joseph, Rollins, David, University of Central Florida
Abstract / Description: Physical lab experiments have shown that the pressure caused by an impinging jet on a granular bed has the potential to form craters. This poses a danger to landing success and nearby spacecraft for future rocket missions. Current numerical simulations for this process do not accurately reproduce experimental results. Our goal is to produce improved simulations to more accurately and efficiently model the changes in pressure as gas flows through a porous medium. A two-dimensional model in...
Show morePhysical lab experiments have shown that the pressure caused by an impinging jet on a granular bed has the potential to form craters. This poses a danger to landing success and nearby spacecraft for future rocket missions. Current numerical simulations for this process do not accurately reproduce experimental results. Our goal is to produce improved simulations to more accurately and efficiently model the changes in pressure as gas flows through a porous medium. A two-dimensional model in space known as the nonlinear Porous Medium Equation as it is derived from Darcy's law is used. An Alternating-Direction Implicit (ADI) temporal scheme is presented and implemented which reduces our multidimensional problem into a series of one-dimensional problems. We take advantage of explicit approximations for the nonlinear terms using extrapolation formulas derived from Taylor-series, which increases efficiency when compared to other common methods. We couple our ADI temporal scheme with different spatial discretizations including a second-order Finite Difference (FD) method, a fourth-order Orthogonal Spline Collocation (OSC) method, and an Nth-order Chebyshev Spectral method. Accuracy and runtime are compared among the three methods for comparison in a linear analogue of our problem. We see the best results for accuracy when using an ADI-Spectral method in the linear case, but discuss possibilities for increased efficiency using an ADI-OSC scheme. Nonlinear results are presented using the ADI-Spectral method and the ADI-FD method.
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Date Issued: 2013
Identifier: CFE0005017, ucf:49998
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005017

Title: Bio-Inspired Cooperative Optimal Trajectory Planning for Autonomous Vehicles.
Creator: Remeikas, Charles, Xu, Yunjun, Kassab, Alain, Lin, Kuo-Chi, University of Central Florida
Abstract / Description: With the recent trend for systems to be more and more autonomous, there is a growing need for cooperative trajectory planning. Applications that can be considered as cooperative systems such as surveying, formation flight, and traffic control need a method that can rapidly produce trajectories while considering all of the constraints on the system. Currently most of the existing methods to handle cooperative control are based around either simple dynamics and/or on the assumption that all...
Show moreWith the recent trend for systems to be more and more autonomous, there is a growing need for cooperative trajectory planning. Applications that can be considered as cooperative systems such as surveying, formation flight, and traffic control need a method that can rapidly produce trajectories while considering all of the constraints on the system. Currently most of the existing methods to handle cooperative control are based around either simple dynamics and/or on the assumption that all vehicles have homogeneous properties. In reality, typical autonomous systems will have heterogeneous, nonlinear dynamics while also being subject to extreme constraints on certain state and control variables. In this thesis, a new approach to the cooperative control problem is presented based on the bio-inspired motion strategy known as local pursuit. In this framework, decision making about the group trajectory and formation are handled at a cooperative level while individual trajectory planning is considered in a local sense. An example is presented for a case of an autonomous farming system (e.g. scouting) utilizing nonlinear vehicles to cooperatively accomplish various farming task with minimal energy consumption or minimum time. The decision making and trajectory generation is handled very quickly while being able to consider changing environments laden with obstacles.
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Date Issued: 2013
Identifier: CFE0005053, ucf:49978
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005053

Title: Degradation of Hydrazine and Monomethylhydrazine for Fuel Waste Streams using Alpha-ketoglutaric Acid.
Creator: Franco, Carolina, Yestrebsky, Cherie, Clausen, Christian, Rex, Matthew, Harper, James, Duranceau, Steven, University of Central Florida
Abstract / Description: Alpha-ketoglutaric acid (AKGA) is an organic acid important for the metabolism of essential amino acids as well as for the transfer of cellular energy. It is a precursor of glutamic acid which is produced by the human body during the Krebs Cycle. AKGA has a specific industrial interest as it can be taken as a dietary supplement and is also widely used as a building block in chemical synthesis.Collectively termed as hydrazine (HZs), hydrazine (HZ) and monomethylhydrazine (MMH) are hypergolic...
Show moreAlpha-ketoglutaric acid (AKGA) is an organic acid important for the metabolism of essential amino acids as well as for the transfer of cellular energy. It is a precursor of glutamic acid which is produced by the human body during the Krebs Cycle. AKGA has a specific industrial interest as it can be taken as a dietary supplement and is also widely used as a building block in chemical synthesis.Collectively termed as hydrazine (HZs), hydrazine (HZ) and monomethylhydrazine (MMH) are hypergolic fuels that do not need an ignition source to burn. Because of the particular HZs' characteristics the National Aeronautics and Space Administration (NASA) at Kennedy Space Center (KSC) and the US Air Force at Cape Canaveral Air Force Station (CCAFS) consistently use HZ and MMH as hypergolic propellants. These propellants are highly reactive and toxic, and have carcinogenic properties. The handling, transport, and disposal of HZ waste are strictly regulated under the Resource Conservation and Recovery Act (RCRA) to protect human health and the environment. Significant quantities of wastewater containing residuals of HZ and MMH are generated at KSC and CCAFS that are subsequently disposed off-site as hazardous waste. This hazardous waste is shipped for disposal over public highways, which presents a potential threat to the public and the environment in the event of an accidental discharge in transit. NASA became aware of research done using AKGA to neutralize HZ waste. This research indicated that AKGA transformed HZ in an irreversible reaction potentially leading to the disposal of the hypergols via the wastewater treatment facility located at CCAFS eliminating the need to transport most of the HZ waste off-site.New Mexico Highlands University (NMHU) has researched this transformation of HZ by reaction with AKGA to form stabilized pyridazine derivatives. NMHU's research suggests that the treatment of HZ and MMH using AKGA is an irreversible reaction; once the reaction takes place, HZ and/or MMH cannot re-form from the byproducts obtained. However, further knowledge relating to the ultimate end products of the reaction, and their effects on human health and the environment, must still be addressed. The known byproduct of the AKGA/HZ neutralization reaction is 6-oxo-1,4,5,6-tetrahydro-pyridazine-3-carboxylic acid (PCA), and the byproduct of the AKGA/MMH reaction is 1-methyl-6-oxo-4,5-dihydro-pyridazine-3-carboxylic acid (mPCA).This research addressed several primary areas of interest to further the potential use of AKGA for HZ and MMH neutralization: 1) isolation of the end-product of the MMH-AKGA degradation process, 1-methyl-6-oxo-4,5-dihydro-pyridazine-3-carboxylic acid (mPCA), and determination of several physical properties of this substance, 2) evaluation of the kinetics of the reaction of AKGA with HZ or MMH, 3) verification of the chemical mechanism for the reaction of the individual hypergols with AKGA, 4) determination of whether the addition of a silicone-based antifoaming agent (AF), citric acid (CA) and/or isopropyl alcohol (IPA) to the AKGA and HZ or MMH solution interferes with the degradation reaction, 4) application of laboratory bench scale experiments in field samples, and 5) determination of the reaction enthalpy of these reactions.
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Date Issued: 2014
Identifier: CFE0005493, ucf:50334
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005493

Title: THE ROLE OF COMMUNICATION TECHNOLOGY IN ADOLESCENT RELATIONSHIPS AND IDENTITY DEVELOPMENT.
Creator: Cyr, Betty-Ann, Berman, Dr. Steven, University of Central Florida
Abstract / Description: Text messaging, e-mail, instant messaging, and social networking sites are changing the way people interact with each other. The popularity of these communication technologies among emerging adults in particular has grown exponentially, with little accompanying research to understand their influences on psychosocial development. This study explores the relationship between communication technology usage (text messaging, e-mail, instant messaging, and social networking) and adolescent...
Show moreText messaging, e-mail, instant messaging, and social networking sites are changing the way people interact with each other. The popularity of these communication technologies among emerging adults in particular has grown exponentially, with little accompanying research to understand their influences on psychosocial development. This study explores the relationship between communication technology usage (text messaging, e-mail, instant messaging, and social networking) and adolescent adjustment among 268 high school students. It was hypothesized that use of communication technology would be related to psychological adjustment, including identity development, relationship attachment and peer conflict. Participants were recruited from three public high schools in central Florida (69% female, 81.9% White). Time spent using communication technology was significantly correlated with psychological symptom severity (i.e. anxiety and depression), identity distress, peer aggression, and existential anxiety. It was also significantly but negatively correlated with relationship avoidance. Degree of usage of communication technology for interpersonal communication was significantly correlated with peer aggression, relationship anxiety, and existential anxiety. Those with a preoccupied style (high in relationship anxiety, low in relationship avoidance) spent significantly more time using communication technology than those in the dismissive (high in avoidance, low in anxiety), fearful (high in both), and secure (low in both) styles. Further analyses and their implications for adolescent development will be discussed.
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Date Issued: 2012
Identifier: CFH0004213, ucf:44908
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0004213

Title: Chemistry and dissipation at mineral surfaces in the space environment.
Creator: Tucker, William, Schelling, Patrick, Britt, Daniel, Kara, Abdelkader, Coffey, Kevin, University of Central Florida
Abstract / Description: The composition and morphology of mineral surfaces is known to play an important role in various phenomena relevant to planetary science. For example, the synthesis and processing of complex organics likely occurs at mineral surfaces strongly affected by the space environment. Furthermore, the dissipative and adhesive properties of dust grains may depend strongly on the chemical state of the surface including the presence of dangling bonds, adsorbates, and radicals. In this dissertation,...
Show moreThe composition and morphology of mineral surfaces is known to play an important role in various phenomena relevant to planetary science. For example, the synthesis and processing of complex organics likely occurs at mineral surfaces strongly affected by the space environment. Furthermore, the dissipative and adhesive properties of dust grains may depend strongly on the chemical state of the surface including the presence of dangling bonds, adsorbates, and radicals. In this dissertation, experimental results are first presented which demonstrate that mineral grains subjected to high temperatures in a reducing environment lead to iron nanoparticles which are strongly catalytic for the formation of complex organic species. Next, results obtained using molecular-dynamics simulations demonstrate that uncoordinated surface atoms in metallic nanoparticles result in plastic deformation, strong dissipation and adhesion during collisions. This can be contrasted with previous simulations which demonstrate significantly weaker dissipation when surface atoms are passivated. Calculations of critical sticking velocities demonstrate that simple coarse- grain models are insufficient for predicting the adhesive behavior of sub-micron sized grains. Next, results are presented describing a computational study illuminating the role of surface chemistry on adhesion and dissipation for iron nanoparticle collisions, which in the case of free radical adsorbates may also contribute to the creation of more complex species. Lastly, to further elucidate dissipation, the direct coupling of harmonic vibrational modes in the dissipation process is established. The results demonstrate broad participation of low and high-frequency modes during a collision during a timescale less than time required for particles to rebound. Hence, our results demonstrate extremely strong likelihood of adhesion during collisions. This approach provides a way to use density-functional theory calculations to directly compute dissipative couplings at mineral interfaces.
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Date Issued: 2019
Identifier: CFE0007545, ucf:52592
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007545

Title: Computational Approach to Electrocatalysis.
Creator: Dhakal, Nagendra, Stolbov, Sergey, Rahman, Talat, Ishigami, Masa, Masunov, Artem, University of Central Florida
Abstract / Description: The main objective of this work is to understand the theoretical basis of the working principle of the Hydrogen fuel cell. We seek the physical basis of the Rational Design Technique, the smart way of preselecting materials from the material-pool, implemented in our study anticipating highly promising electrocatalysts for promoting the conversion of chemical energy stored in hydrogen molecules into the electrical energy. It needs the understanding of the relationship among the compositions of...
Show moreThe main objective of this work is to understand the theoretical basis of the working principle of the Hydrogen fuel cell. We seek the physical basis of the Rational Design Technique, the smart way of preselecting materials from the material-pool, implemented in our study anticipating highly promising electrocatalysts for promoting the conversion of chemical energy stored in hydrogen molecules into the electrical energy. It needs the understanding of the relationship among the compositions of the materials under consideration, their electronic structure and catalytic activities. We performed the first principle DFT calculations to achieve the goal.Our work is focused first on the issues in hydrogen oxidation reaction taking place in anode compartment of the cell. Next comes up with the issues with Oxygen Reduction Reaction taking place in cathode compartment. Finally, we focus on mechanisms underlying binding of small molecules on substrates.Platinum perfectly catalyzes hydrogen oxidation reaction on the hydrogen fuel cell anodes. However, it has at least two drawbacks: a) it is too expensive; b) it has a low tolerance to CO poisoning. Pt-Ru bi-functional catalysts are more tolerant to CO, but they are still very expensive. In this work, we performed first-principle studies of stability and reactivity of M/W (110) structures, where M = Pd, Ru, Au monolayers. All three systems are found to be stable: formation energy of MLs is significantly higher than cohesive energy of the M-elements. The calculated binding energies of H, H2, OH, CO, and H2O were used to obtain the reaction free energies. Analysis of the free energies suggests that Au-W bonding does not activate sufficiently Au monolayer, whereas Ru/W (110) is still too reactive for the CO removal. Meanwhile, Pd/W (110) is found to catalyze hydrogen oxidation and at the same time to be highly tolerant to the CO poisoning. The latter finding is explained by the fact that CO binds much weaker to Pd on W (110) than to Pt, while the OH binding is strong enough to ensure CO oxidation. The obtained results are traced to the electronic structure of the systems.Oxygen Reduction Reaction (ORR) is the heart core reaction in fuel cells, Proton Exchange Membrane Fuel cell and DEMFC. However, the reaction is not so obvious and need suitable electrocatalyst. Pt or Pt-based catalysts are found to be the best catalyst so far. But, its cost and shortage make it not feasible economically. Moreover, lower onset potential (maximal electrode potential at which the reaction can proceed) of such catalysts is offering another limitation to fuel cell performance. Research has been conducted in many directions for lowering the cost by replacing the Pt with some other elements of lower cost or reducing the Pt-load in the material; and even more finding the material performing better than Pt. In this paper, we've tried to understand the ORR mechanism and look for the material that could be potential option to Pt. Our calculations suggest that for monolayer of Pt on 5 layered slab of Nb or Mo the onset potential is the same as for Pt, while cost of these systems are much lower than that of Pt. Presence of water changes the reaction rate very minimum. Rational design method facilitates the research of selecting the appropriate catalyst and saves time and effort significantly. The result shows that the d-band center model is not accurate to describe the reactivity of the catalyst.For decades, adsorbates' binding energy (????) has been used as an indicator of the adsorbate-substrate bond strength (??????). Thus, although one can compute accurately any ?? models to gauge bond-strength are developed and applied to rationalize and anticipate ????'s because that is a key aspect in the rational search for efficient catalysts. Yet bond-strength alone fails to predict ???? trends. Therefore, quantifying and understanding the difference between ???? and ?????? is essential to catalysts design. Indeed, the adsorbate-substrate bond formation perturbs the substrate's electronic charge density, which reduces ???? by the energy attached to such perturbation: ??????????. Here, with the example of carbon monoxide adsorption on metal-doped graphene, we show that ?????????? may exceed 1 eV and render an unusual situation: although the EB of CO to the Au-doped graphene indicates that binding does not happen, we find evidence of a strong bond between CO and the substrate. Thus, in this case, the large ?????????? totally disrupt the equivalency between ?????? and ???? we also propose a method to compute ?????????? that bypasses dealing with an excited electronic state of the system.
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Date Issued: 2017
Identifier: CFE0006583, ucf:51336
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006583

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