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Chan, XinniSurvival Processing Effect on Memory for Social Information
Doctor of Philosophy, University of Toledo, 2017, Psychology - Experimental
Recent research has suggested that our memory systems have evolved to prioritize processing information that enhances our fitness (e.g., location of food, distance of predators). In a provocative line of research, a number of studies have shown that people who merely think about survival demonstrate enhanced recall for word lists compared to those in control conditions who think about non-survival topics (e.g., Kang, McDermott, & Cohen, 2008; Nairne, Thompson, & Pandeirada, 2007; Weinstein, Bugg, & Roediger III; 2008). Researchers have attributed this to an evolved sensitivity to fitness-relevant content, which enhances attention and memory processes when prompted to think about survival contexts. More recent research has suggested cognitive explanations rather than evolutionary motives, such as encoding stimuli in ways that are congruent with the context, explain these effects (Butler, Kang, & Roediger III, 2009). To date, nearly all tests of the survival processing advantage have been conducted in non-social domains involving word lists and no study has assessed the functional value of the survival processing advantage for outcomes other than memory, such as judgments and decisions. Given the proximal role of social information in modern and ancestral life, this dissertation tested between evolutionary and cognitive explanations (i.e., a congruency-incongruency account) of the survival processing advantage for social memory and judgments/decisions. After establishing the appropriateness of stimuli in a pilot study, participants in the main study were randomly assigned to read one of two scenarios: a survival scenario where participants imagined being stranded in foreign grasslands or a non-survival scenario where they imagined leading the robbery of a well-guarded bank. As part of the task, participants were told that they needed to connect with other social groups to assist in meeting the scenario goal, wherein information about four social groups were presented. Critically, the groups possessed different numbers of characteristics that were congruent or incongruent with survival and leading a robbery. The main dependent measures were recall and recognition of the group characteristics and the accuracy of participants’ decisions and judgments about the groups (e.g., whether they decided to join the group possessing the most goal-relevant traits). Overall, the results more clearly supported the congruency-incongruency account than the survival processing account. First, participants recalled social traits best when the traits were congruent with the scenario context, regardless of whether it was a survival or robbery context. However, recognition did not differ as a function of condition or trait type. Second, participants in the robbery and survival conditions chose the “correct” group at equivalent and greater-than-chance levels and judged groups with the most goal-relevant traits more favorably than groups with the least goal-relevant traits. This latter set of results suggests that participants used the scenario context in a functional way to guide their judgments and decisions. Implications for several different research literatures are discussed.

Committee:

Jason Rose (Committee Chair); Yueh_Ting Lee (Committee Co-Chair); Daniel Kruger (Committee Member); Andrew Geers (Committee Member); Revathy Kumar (Committee Member)

Subjects:

Psychology

Keywords:

Survival Processing Effect; Memory; Social Information; Evolutionary Motive; Congruent-incongruent

Clos, Timothy GeorgeCompactness of Hankel Operators with Continuous Symbols on Domains in ℂ2
Doctor of Philosophy, University of Toledo, 2017, Mathematics
This thesis will present original work characterizing compactness of Hankel operators with continuous symbols on the Bergman spaces of bounded convex Reinhardt domains in ℂ2. We assume no boundary regularity or symbol regularity other than continuity of the symbol up to the closure of the domain.

Committee:

Sonmez Sahutoglu, Ph.D (Committee Chair); Zeljko Cuckovic, Ph.D (Committee Member); Trieu Le, Ph.D (Committee Member); Akaki Tikaradze, Ph.D (Committee Member); Yunus Zeytuncu, Ph.D (Committee Member)

Subjects:

Mathematics

Keywords:

Several complex variables;

Bafakeeh, Omar TMicro/Nano Surface Finish Single Side Electrolytic In-Process Dressing (ELID) Grinding with Lapping Kinematics of Sapphire
Doctor of Philosophy, University of Toledo, 2017, Industrial Engineering
The demand for Sapphire ( a-AL2 O3 ) has increased significantly, due to its excellent reliable properties. Sapphire, known for its high hardness and brittleness, has excellent optic, mechanical, and physical properties. Sapphire is used in many different applications such as aerospace, optics, electronics, and in other industries. Machining of sapphire is challenging due to its high hardness and brittleness. The manufacturing of such material is very expensive because the tool wear is very high and longtime machining. Single side grinding is sometimes preferable over conventional grinding because of the ability to provide flat surfaces for ceramic materials. The use of electrolytic in-process dressing (ELID) helps reduce machining time. The use of the kinematics of lapping with the ELID will help reduce machining time in addition to eliminating the use of lapping and polishing. This current study examines five parameters with three levels each. A full factorial design, for both roughness (Ra) and material removal rate (MRR) are be conducted to present mathematical models which predict future results. Three grinding wheels with different mesh sizes are be used. The influence of the grain size on the result will be investigated. The kinematics of the process will be investigated based on the effect of different eccentricities. The parameters used in this study are; different wheel mesh sizes, different pressures, different eccentricities, different spindle speed, and different wheel speed ratios; each of these parameters are in three levels.

Committee:

Ioan Marinescu (Committee Chair); Abdollah Afjeh (Committee Member); Mansoor Alam (Committee Member); Sarit Bhaduri (Committee Member); Matthew Franchetti (Committee Member)

Subjects:

Industrial Engineering; Mechanical Engineering

Keywords:

ELID, Single Side Grinding, Fine Grinding, Sapphire

Lawson, Monica L. The Reliability of Children’s Event Reports to Their Mothers
Doctor of Philosophy, University of Toledo, 2016, Psychology - Experimental
Children involved in maltreatment investigations often discuss allegations with their mothers before formal reports are made to authorities. The primary purpose of the current study was to evaluate the amount and the accuracy of information children reported to their mothers about a non-shared experience. Children aged 4- to 7-years-old (N = 142) individually participated in a staged event and discussed the experience with their mothers approximately six-days later. Prior to interviewing children, mothers were provided with some details about the non-shared event. Accurately-biased mothers had accurate information about the event. Inaccurately-biased mothers had both accurate and inaccurate information about the experience. Individual difference factors including children’s age, maternal reminiscing style, and attachment quality were hypothesized to moderate the relationship between maternal bias and children’s reports. The results revealed older children had highly reliable reports regardless of maternal bias or maternal reminiscing style. However, younger children with inaccurately biased and high elaborative mothers reported less accurate and more inaccurate information about the event compared to younger children with inaccurately-biased and low elaborative mothers. Additionally, children of mothers with insecure attachment quality reported fewer details and made more inaccurate statements regarding the event. Results suggest that the mnemonic consequence of discussing past experiences with mothers varies depending on maternal bias, children’s age, maternal reminiscing style, and attachment quality. Forensic and theoretical implications of the findings are discussed.

Committee:

Kamala London, PhD (Committee Chair); Stephen Christman, PhD (Committee Member); Sarah Francis, PhD (Committee Member); Jason Rose, PhD (Committee Member); Lisa Pescara-Kovach, PhD (Committee Member)

Subjects:

Developmental Psychology; Psychology

Keywords:

Children; Eyewitness testimony; Maternal reminiscing style; Attachment; Suggestibility

Miranda, Michael AngeloBio Based Active Barrier Materials and Package Development
Doctor of Philosophy, University of Toledo, 2016, Chemical Engineering
The food and packaging industries are interested in approaches to reduce the permeability of oxygen in polyethylene terephthalate (PET) to extend the shelf-life of product. This has led to considerable research in barrier improvement including the use of active scavenger that permanently bind oxygen. The purpose of this work is to investigate the use of renewably sourced unsaturated fatty acids as scavengers to reduce the O¬2 permeability in PET. Specifically fatty acids were characterized and incorporated within PET using both blended and reactive extrusion to analyze the impact on thermal-mechanical and oxygen transport properties. Oleic, linoleic and linolenic acid are renewably resourced unsaturated fatty acids that are being investigated as active scavenger. Utilization of scavenger capacity and kinetics of oxidation are two key parameters that must be considered while selecting a scavenger. The O¬2 uptake capacities and the utilization of scavenger sites analysis were used to determine the most appropriate scavenger used to make a copolymer with PET. Linoleic acid was chosen due to its higher utilization capacity and relatively fast kinetics the cost was also taken into account. Thus linoleic acid was used in preparation of PET/Scavenger system. The effect of addition of unsaturated fatty acid on the thermal, mechanical properties and morphology of PET, were analyzed by preparing blends of PET/linoleic acid of loading of (0.25-2 weight %). The presence of the scavenger were analyzed using end group analysis where an increase in carboxyl end group was determined and NMR to obtain the peaks for the fatty acid. The appropriate method to determine molecular weight was also established. Effects of permeation through amorphous and biaxial oriented films with and without linoleic acid were investigated. The bottles were produced in two different ways (i) reactive extruded bottle and (ii) blended bottles (0.5% weight loading of Linoleic acid). The mechanical properties and density of the bottles were similar. The oxygen permeability of these bottles side wall was lower than that of PET. NMR on sample that has been exposed to oxygen was conducted to confirm the reactivity of linoleic acid with oxygen.

Committee:

Maria Coleman (Committee Chair); Saleh. A. Jabarin (Committee Co-Chair); Sridhar Vimajala (Committee Member); Yakov Lapitsky (Committee Member); Young- Wah Kim (Committee Member)

Subjects:

Chemical Engineering; Gases; Packaging; Polymers

Tebbe, Hope MEvaluation of Indoor Air Quality in Four Nursing Home Facilities in Northwest Ohio
Master of Science in Occupational Health, University of Toledo, 2017, Occupational Health (Industrial Hygiene)
Indoor air quality (IAQ) is considered one of the top five environmental risks to the public’s health. Older adults are more vulnerable to health complications associated with indoor air contaminants because of their decreased immune system and age-associated health problems, as well as the fact that they spend up to 95 percent of their time indoors. Area air sampling was conducted in the nursing home section of four long term care facilities, three days at each facility (12 days total). Particle concentrations (PM2.5, PM10, Total Particulate matter (TPM), Ultrafine Particles (UFP), temperature, and humidity were measured. Two minute samples were collected during seven Sampling Sessions. Up to nine indoor locations were sampled, representing the various occupied spaces in each nursing home, along with an outside location for comparison. Results of Analysis of Variance (ANOVA) by Facility demonstrated significant differences (p<0.001) in PM concentrations and UFP counts. One Facility had higher particulate concentrations at all Sampling Locations which may include contributions from geographic location, vehicular traffic, or resident clustering. ANOVA by Sampling Location demonstrated significant differences (p<0.001) in PM concentrations and UFP counts. In general, the highest UFP and PM concentrations were seen in the kitchen, satellite kitchen, and hair salon, especially at times when the staff and residents were active in these rooms. Significant differences were seen in UFP counts (Facilities 1 and 3) and PM2.5 (Facility 2) by Sampling Session. The highest concentrations were found for the Sampling Sessions in the mid-morning and mid-afternoon which were during peak times of activity for the residents. Although maximum temperature measurements exceeded ASHRAE winter guidelines, this may be appropriate for older residents who prefer a warmer temperature. While most median particle values were below ASHRAE guidelines, maximum values did exceed occasionally in the hair salon and kitchen at all facilities. Various indoor Sampling Location PM concentrations or UFP counts exceeded the outdoor levels at all four facilities. Although the median PM values did not exceed the ASHRAE standards it is unknown whether older adults may still experience significant health complications with these PM concentrations. In addition staff who spend extended amount of times in the kitchen and hair salon could be exposed to higher levels of PM. IAQ in hospitals and similar environments, such as nursing homes, may require a higher level of care because of the vulnerable population.

Committee:

April Ames, PhD, CIH (Committee Chair); Victoria Steiner, PhD (Committee Member); Akbar-Khanzadeh Farhang, PhD, CIH (Committee Member); Sheryl Milz, PhD, CIH (Committee Member)

Subjects:

Aging; Alternative Medicine; Engineering; Environmental Engineering; Environmental Health; Environmental Science; Environmental Studies; Gerontology; Health; Health Care Management; Health Sciences; Medicine; Occupational Health; Occupational Safety; Public Health; Welfare

Keywords:

Particulate Matter; Nursing Homes; Elderly; Indoor Air Quality; PM; IAQ; ASHRAE; Air Quality; susceptible population; buildings; Aging

Prasad, VanditaDesigning and Implementing an Evaluability Assessment of a Career-Technical Education Program as the First Step towards Validating Program Effectiveness: A Case Study of Toledo Technology Academy
Doctor of Education, University of Toledo, 2017, Educational Administration and Supervision
Career Technology Education (CTE) program evaluations have been mostly completed for compliance and monitoring purposes. Hence, they have limited use in establishing program effectiveness or for program improvement. Moreover, engaging in program evaluations can be time consuming and costly, especially for programs that have not been evaluated in the past. In these situations, it is recommended that a determination of program readiness for an evaluation be conducted first through an evaluability assessment (EA). This study demonstrated how an EA could be conducted. The purpose of this study was to implement an EA of a local CTE program to determine if and to what extent the program had the systems in place that would generate formal evidence of its effectiveness as well as inform the program improvement process. This study was designed as a case study, targeting a specific CTE program - Toledo Technology Academy, a 7-12 Toledo Public School that prepares students in the area of Engineering and Sciences Technologies. The study methodology used the 5-task EA model outlined in the Evaluability Assessment: Examining the Readiness of a Program for Evaluation developed by the Juvenile Justice Evaluation Center (2003). Task 1 and 2 were conducted to understand program history, design, and implementation. Task 3 looked at the program’s capacity for data collection, management, and analysis. Task 4 assessed the overall likelihood of TTA’s program in attaining its goals and objectives. Finally, Task 5 analyzed TTA program’s capacity for data collection, management, and analysis to determine if the collected data were useful in determining program effectiveness and improvement. For Tasks 4 and 5, first, specific EA rubrics were designed and then applied to the program. For Task 5, the rubrics were created for three of the 10 standards listed on the Ohio’s Quality Program Standards for Career Technical Programs (2016). The findings indicated that the TTA program had a formal design and was implemented as designed. Overall the program collected an abundance of data, but data analysis was very minimal. Furthermore, TTA was highly likely to achieve its goals and objectives. However, the study revealed that though TTA data collection was adequate in some areas, it needed some or major improvement in others. The study produced numerous recommendations for the TTA program. It also made a significant methodological contribution (especially in the field of CTE evaluation) by presenting a detailed methodology for conducting an EA with simple steps that could be used by a CTE administrator.

Committee:

Svetlana Beltyukova (Committee Co-Chair); Randy Vesely (Committee Co-Chair); Nancy Staub (Committee Member); Gale Mentzer (Committee Member)

Subjects:

Education; Educational Evaluation; Secondary Education; Vocational Education

Keywords:

evaluability assessment, career-technical education, program, evaluation, case-study

Booker, Joseph JCharacterizing the Role of Feedback and Protostellar Properties in the Orion Molecular Clouds
Doctor of Philosophy, University of Toledo, 2017, Physics
A central question in the study of star formation is: what sets the mass distribution of nascent stars? This distribution appears to vary little (especially at the low mass end) throughout our galaxy and others, despite variations in the heavy element abundance, interstellar radiation field, and amount of gas available. This work is a component of the Herschel Orion Protostar Survey (HOPS), a program to characterize hundreds of protostars in the Orion Molecular Clouds, largest site of on-going star formation with 0.5 kiloparsec. As part of the HOPS program, we have spectral energy distributions with a wavelength coverage of 1.2-870 µm, making this one of the most well characterized samples of nearby star formation. We extend this work with a large survey imaging 283 protostars in Orion with the Hubble Space Telescope, enabling us to observe with 80 AU resolution at 1.6 µm. At this wavelength, light from the central photosphere is scattered off the dust ubiquitous throughout the gas, resolving the structure of the protostellar envelope. We use the high angular resolution to perform a morphological study of the nearby protostellar gas (the envelope), finding that our morphologies are indicative of evolutionary trends. The high resolution of this data makes it uniquely suited for finding unambiguously edge-on protostars (of which we report thirteen at high confidence) and for tracing the structure of cavities cleared by protostellar outflows. We report on one of these unambiguously edge-on protostars, HOPS 171, which we've studied in detail with the Atacama Large Millimeter/submillimeter Array to find a complex structure. We use an edge detection routine to perform the analysis on tracing cavities caused by outflows, and report the first application of such a routine to study the role of feedback on the envelope. Using evolutionary diagnostics, we find no evidence for the growth of these outflow cavities as protostars evolve through the first 100000 years. This contrasts with previous authors who have invoked the growth of the outflow cavities as a mechanism for clearing the gas infalling into forming stars. We validate our approach by confirming that the number of protostars without observed outflow cavities is consistent with the distribution of cavity sizes inferred from our observation; i.e., that we are not appreciably affected by observation bias. We conclude that the reduction/halting of infall and the low star formation efficiency inferred from molecular clouds cannot be explained with envelope clearing by outflows.

Committee:

S. Thomas Megeath (Committee Chair); Rupali Chandar (Committee Member); Steve Federman (Committee Member); Stella Offner (Committee Member); Nikolas Podraza (Committee Member)

Subjects:

Astronomy; Astrophysics

Keywords:

protostars;infrared astronomy;submillimeter astronomy;astronomy;physics;astrophysics

Nabiyouni, NasimA Lean Six-Sigma Approach to Red Bag Waste Management in Hospitals
Master of Science, University of Toledo, 2016, Engineering
Lean Six-Sigma methodology is an approach to improve value streams in term of meeting customer desire by elimination waste and defect. This method is a combination of lean thinking and Six-Sigma. Lean thinking provides an integrated overlook tool to business operations to perform more coherent technologies and assets flow instead of focusing to improve separate departments. Six-Sigma improves quality by decreasing the number of defects. The objective of this thesis is to eliminate errors in Regulated Medical Waste specifically red bag wastes. In order to achieve the goal of the research, lean six-sigma application in healthcare, a full process analysis of red bag waste in hospitals (including human factors), and an economic-environmental impact study of red bag waste and minimization methodology has been studied. Red bag waste is one type of regulated medical waste (RMW), also known as `biohazardous’ waste or 'infectious medical’ waste. This portion of the waste stream by definition is contaminated by blood, body fluids or other potentially infectious materials. In case of improper management, significant risk of transmitting infection would threaten the public heat and environment. In order to prevent confusion and mistakes in discarding these wastes, specified regulations and guidelines are developed. Each category of regulated medical waste has special handling requirements that may be state-specific. This thesis reveals the current red bag waste problems in an existing healthcare facility, a hospital in Toledo, Ohio. The study develops a universal model for improving red bag waste management value stream and focuses on human factors as key elements to improvement.

Committee:

Mathew Franchetti, Prof (Committee Chair); Kumar Ashok, Prof (Committee Member); Spivak Alex, Prof (Committee Member)

Subjects:

Engineering; Health Care Management

Keywords:

Lean, Six-Sigma, Lean in Healthcare, Red Bag Waste Management, Medical Waste Management

Reynolds, TravisMuscle Activity of Primary and Core Muscles of the Seated Overhead Press with Unstable Loads
Master of Science, University of Toledo, 2017, Exercise Science
Core muscle strength and coordination are important components to resistance training and sports performance. Unstable training (UT), further divided into unstable surface training (UST) and unstable load training (ULT), is commonly chosen to improve core muscle strength. ULT has been accomplished by suspending resistance from a barbell with bands, allowing it to move vertically, but research has not been done on a horizontal type of ULT. The purpose of this study was to measure the impact of horizontal dynamic instability (HDI) on prime mover and core stabilizer muscle activity, during the seated overhead press, through use of electromyography (EMG). HDI was compared to a traditional type of ULT as well as stable load training (SLT). Thirteen resistance trained males (age = 24.1±2.4 years, height = 178±7.2cm, mass = 84.1±9.4 kg) participated in all three condition assignments. Subjects tested their 5-RM strength on the seated overhead press and performed five repetitions at 50% 5-RM strength for condition assignments. Electrodes were attached to 8 muscles (anterior deltoid, triceps brachii, upper trapezius, right & left external oblique, right & left rectus abdominis, erector spinae). Concentric and eccentric muscle actions were analyzed separately across all repetitions. Mean voltage of activation was acquired and processed (band pass filter 10-500 Hz, rectified, RMS 50ms window and normalized) and significance was set at p <0.05. A two-way RM ANOVA was used to compare condition x muscle action. Anterior deltoid and upper trapezius activity was higher during ULT concentric compared to SLT and HDI concentric. Erector spinae activity was higher during SLT and HDI concentric compared to ULT concentric. Left external oblique activity differed significantly between HDI and ULT eccentric, but no differences occurred at the right external oblique. These results suggest that HDI may require external oblique activity to a similar magnitude as traditional ULT. Continued research on HDI should address other exercises or loading intensities.

Committee:

Suzanne Wambold, Ph.D. (Committee Chair); Charles Armstrong, Ph.D. (Committee Member); Grant Norte, Ph.D. (Committee Member)

Subjects:

Experiments; Physical Education; Physiology; Sports Medicine

Dhar, SamirAddressing Challenges with Big Data for Maritime Navigation: AIS Data within the Great Lakes System
Doctor of Philosophy, University of Toledo, 2016, Spatially Integrated Social Science
The study presented here deals with commercial vessel tracking in the Great Lakes using the Automatic Identification System (AIS). Specific objectives within this study include development of methods for data acquisition, data reduction, storage and management, and reporting of vessel activity within the Great Lakes using AIS. These data show considerable promise in tracking commodity flows through the system as well as documenting traffic volumes at key locations requiring infrastructure investment (particularly dredging). Other applications include detecting vessel calls at specific terminals, locks and other navigation points of interest. This study will document the techniques developed to acquire, reduce, aggregate and store AIS data at The University of Toledo. Specific topics of the paper include: data reducing techniques to reduce data volumes, vessel path tracking, estimate speed on waterway network, detection of vessel calls made at a dock, and a data analysis and mining for errors within AIS data. The study also revealed the importance of AIS technology in maritime safety, but the data is coupled with errors and inaccuracy. These errors within the AIS data will have to be addressed and rectified in future to make the data accurate and useful. The data reduction algorithm shows a 98% reduction in AIS data making it more manageable. In future similar data reduction techniques can possibly be used with traffic GPS data collected for highways and railways.

Committee:

Peter Lindquist (Committee Chair); Kevin Czajkowski (Committee Member); Neil Reid (Committee Member); Mark Vonderembse (Committee Member); Richard Stewart (Committee Member)

Subjects:

Geographic Information Science; Geography; Information Technology; Remote Sensing; Social Research; Transportation

Keywords:

Automatic Identification System , AIS, Big Data, Data Reduction Technique, Vessel Path, Vessel Call, Great Lakes, Maritime, VTS

Esakov, EmilyCharacterization of a Novel Pre-Diabetic Murine Model for Type 1 Diabetes
Doctor of Philosophy, University of Toledo, 2016, Medicinal Chemistry
It has been shown in the non-obese diabetic (NOD) mouse model that type 1 diabetes (T1D) is an autoimmune disease characterized by insulitis and T cell-mediated destruction of pancreatic islet beta cells. The insulin receptor (IR) is a chemotactic receptor capable of driving T cell movement in response to insulin. To this end, characterizing IR expression is of key importance for understanding the pathogenesis of diabetes. T cells may be driven to infiltrate pancreatic islets due to a high level of IR on their surface. The purpose of this project is to phenotype the transgenic BL/6-CD3FLAGmIR (non-diabetic) mouse model to better understand the role of increased IR on the CD3+ T cell surface in relation to pancreatic insulitis. This animal model shows onset of insulitis, but animals do not become diabetic making them an efficient model to study trafficking of CD3+ T cells from the spleen to the pancreas as the altered T cells are FLAG tagged. If IR expression is established as a mechanism to move T cells into islets, then down regulation or blocking of IR expression specifically in T cells will provide a new therapeutic target to block cell movement into the pancreas, thus preventing T1D.

Committee:

Marcia McInerney (Committee Chair); Katherine Wall (Committee Member); Hermann Von Grafenstein (Committee Member); Andrea Kalinoski (Committee Member)

Subjects:

Immunology; Pharmacy Sciences

Pradhan, PujaReal Time Spectroscopic Ellipsometry (RTSE) Analysis of Three Stage CIGS Deposition by co-Evaporation
Doctor of Philosophy, University of Toledo, 2017, Physics
Spectroscopic ellipsometry (SE) is a powerful tool to characterize multilayered thin films, providing structural parameters and materials optical properties over a wide spectral range. Further analyses of these optical properties can provide additional information of interest on the physical and chemical properties of materials. In-situ real time SE (RTSE) combines high surface sensitivity with fast data acquisition and non-destructive probing, thus lends insights into the dynamics of film growth. In this dissertation, the methods of SE have been applied to investigate the growth and properties of material components used in the CIGS thin film photovoltaic technology. Examples of RTSE data collection and analyses are demonstrated for the growth of selenium (Se), molybdenum diselenide (MoSe2) and copper selenide (Cu2-xSe), used in CIGS technology which can then be applied in complete analysis of three-stage CIGS deposition by co-evaporation. Thin film Mo deposited by sputtering is the most widely used back contact for solar cells using CIGS absorbers. In this study, in-situ and real time characterization have been utilized in order to investigate the growth as well as the structural, optical, and electronic properties of Mo thin films deposited by DC magnetron sputtering at different substrate temperatures. In these studies, the surface roughness on the Mo is observed to decrease with increasing substrate temperature. The growth rate, nucleation behavior, evolution of surface roughness and development of void structures in Mo show strong variations with deposition temperature. In depth analyses of (e1, e2) provide consistent estimates of void fraction, excited carrier mean free path, group speeds of excited carriers and intrinsic stress in the films. Complementary ex-situ characterization of the as deposited Mo films included XRD, resistivity measurements by four-point-probe, SEM, and profilometry. This dissertation describes the research performed on the (In1-xGax)2Se3 (IGS) thin films with different Ga composition (x) and different IGS bulk layer thicknesses. The (e1, e2) database for IGS was obtained at 400°C by RTSE starting from films deposited by co-evaporation from fluxes of In, Ga, and Se with different x as in the stage I of three-stage co-evaporation process. The goal of this study is to develop a dielectric function database of IGS films with different x, enabling composition monitoring and thickness control during IGS deposition. RTSE has also been applied successfully in this dissertation research for real time monitoring of Cu-poor to Cu-rich and Cu-rich to Cu-poor transitions during the growth of CIGS films by three-stage co-evaporation. RTSE analyses for all three stages of CIGS growth have been presented including new results for IGS-to-CIGS conversion throughout stage II, Cu2-xSe development at the end of stage II, and Cu2-xSe to CIGS conversion in stage III. Thus, it has been demonstrated that in-situ RTSE combines high thickness, phase, and compositional sensitivity with fast non-invasive data acquisition, thus providing unique insights into the dynamics of CIGS film growth. This non-destructive, high speed capability has the potential to supplement or replace existing monitoring techniques applied for multi-stage co-evaporation of CIGS in both laboratory and industry settings. For further insights into the effect of deposition temperature on device performance, a higher than standard substrate temperature was utilized for the growth of CIGS thin films. Elevation of the substrate temperature for stage II/III deposition from 570C to 620C has led to significant improvements in the efficiency of the CIGS solar cell. The highest efficiency CIGS solar cell obtained in this study is 17.4%.

Committee:

Robert Collins (Committee Chair); Nikolas J. Podraza (Committee Member); Bo Gao (Committee Member); Jacques G. Amar (Committee Member); Dean M. Giolando (Committee Member)

Subjects:

Materials Science; Physics; Solid State Physics

Keywords:

Spectroscopic Ellipsometry; RTSE; selenium; molybdenum diselenide ; copper selenide; Molybdenum; dielectric function;three-stage Copper Indium Gallium di-selenide deposition by co-evaporation

Ariss, Laila DianeDifferentiated Instruction: An Exploratory Study in a Secondary Mathematics Classroom
Doctor of Philosophy, University of Toledo, 2017, Curriculum and Instruction: Secondary Education
This case study explores the different approaches to teaching inside a differentiated instruction classroom. The research will be conducted at a college preparatory high school with an emphasis on using various approaches to differentiated instruction to enhance students’ comprehension of Advanced Algebra II. Data collection will include students’ journal reflections, direct-observations, participant-observations, lesson plans, physical artifacts, various students’ assessments, and survey-interviews. The study followed a mixed method design and consisted of two parts qualitative and quantitative data collection and analyses. Both data will be analyzed using excel sheets and ATLAS.ti software. In addition to studying the effects of differentiated instruction on the teacher, the focus of this study will be on mathematics differentiated instruction classroom and how the researcher will relate students’ experience in class to the quantitative outcome of the data.

Committee:

Leigh Chiarelott (Committee Chair); Debra Johanning (Committee Member); Berhane Teclehaimanot (Committee Member); Victoria Stewart (Committee Member)

Subjects:

Curricula; Curriculum Development; Education; Educational Theory; Higher Education; Instructional Design; Mathematics; Mathematics Education

Keywords:

Differentiated Instruction;Mathematics Classroom;Learning style;Learning Profile;Content;Assessment; Process;Product;ATLAS-ti;Quantitative Research;Qualitative Research;Mixed Method Approach;Data;Frequency Table;Median;Data Analysis;Instructional Strategy

Salem, Nada MUnderstanding Humor, Expressions, Profanity, and Cartoons in a Bilingual and Bi-Cultural Context
Master of Arts and Education, University of Toledo, 2017, English (as a Second Language)
This study examines whether different personal attributes could affect our understanding and interpretation of concepts that are foreign to us due to linguistic or cultural reasons. The attributes in question in this research are religion, gender, educational level, and native language of the subjects. A seven-question survey is used to inquire about these features, and based on the answers, a pool of participants is randomly selected. The core of the study consists of a questionnaire based on four sections. The first contains expressions pertaining to the Arab culture, the second has expressions that reflect American culture. The third and the fourth sections comprise respectively profanity and vulgarity expressions and cartoons all familiar to American culture. The sample I select for testing represents the different attributes mentioned above and spreads across three groups: native English speakers, native Arabic speakers, and non-native English or Arabic speakers (like Latinos, Indians and Asians). This research is conducted partly at the University of Toledo with participants who work or study there, and the other part is within the Toledo area, with participants who are friends and acquaintances from the Toledo Arab community. The data I collect is tested statistically to find out if there is any correlation or difference between the properties of my participants with the answers they choose on their questionnaires. Finding whether there is a correlation or not or a difference or not aids in finding out if the participants’ attributes had altered their interpretation and understanding of each section. The statistical results showed that most of these attributes had no correlation and showed no difference by the participants’ responses. The only two attributes that showed some correlation or difference were educational level and native language. I hope that my findings can be helpful to future research aimed for the betterment of second language acquisition strategies of instruction by showing what attributes should be focused on in making those strategies more effective and practical. My suggestion for future research is to study a much larger sample and look for interactions among variables specific to the sample.

Committee:

Douglas Coleman (Committee Chair); Samir Abu Absi (Committee Member); Gaby Semaan (Committee Member)

Subjects:

Education; English As A Second Language

Keywords:

Cartoon, Arabic expressions, Profanity, English expressions, Bi- cultural, Bilingual, interpretation,

Stanley , Wendy LAn Exploratory Case Study of How a Professional Learning Community is Being Implemented in an Elementary School from the Perspective of the Teachers
Doctor of Philosophy, University of Toledo, 2017, Curriculum and Instruction
An Abstract of An Exploratory Case Study of How a Professional Learning Community is Implemented in an Elementary School from the Perspective of the Teachers by Wendy L. Stanley Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Curriculum and Instruction The University of Toledo May, 2017 The purpose of this qualitative research was to use a case study methodology to explore and describe in detail the process the teachers and support staff followed to implement a professional learning community in their elementary school. There has been little research on the how professional learning communities emerge and are implemented initially from an educators perspective. The three research questions that were addressed in this study were: (1) How do teachers describe their experiences as they transition from traditional professional development to a professional learning community, (2) What is the process the teachers and staff followed to implement the professional learning community model at Indian Trail Elementary School (ITES), (3) Does this process represent the conceptual framework for professional learning communities? The analysis of the teachers and support staffs’ experiences provides a deep and rich description of the journey the teachers and staff undertook during the transformation of the professional learning community in their school. It provides information on how the teachers and support staff embraced the concepts and practices, and launched a new professional learning community in their school with the entire staff. The main contribution of this study is the finding that the teachers and support staff were able to develop, implement, and transform their elementary school into a professional learning community through the use of three different resources: (1) the DuFour et al., professional learning community model, (2) the Solution Tree Conference, and (3) the summer course with a knowledgeable instructor.

Committee:

Leigh Chiarelott, PhD (Committee Chair); Mark Templin, PhD (Committee Member); Edward Janak, PhD (Committee Member); Casey Reason, PhD (Committee Member)

Subjects:

Curricula; Curriculum Development; Early Childhood Education; Education; Educational Leadership; Teaching

Keywords:

Professional Learning Communities

Wernert, Sean PatrickThe Socio-ecological Influences of College Bullying Behavior: A Phenomenological Study of Student Perceptions
Doctor of Philosophy, University of Toledo, 2017, Educational Psychology
Using Urie Bronfenbrenner’s socio-ecological model of development as a theoretical framework, the purpose of this qualitative, phenomenological study was to examine how college students perceive and understand the bullying phenomenon— as well as the influences and consequences— on campus at University X; a private, religiously affiliated, large, research university. A total of fifteen students representing each undergraduate academic class and college at University X were interviewed using a single interview protocol. The semi-structured interview consisted of open-ended questions allowing the participants to describe their own understanding and perceptions of what constitutes bullying as well as what they perceive to be its influences and consequences. Using a constant comparative analysis of transcribing, coding and analyzing the interviews, the researcher found that college students at University X closely define bullying in the same way research has but exclude the concept of repetition from their understanding. In addition, the participants understand all four forms of bullying— physical, verbal, relational, and cyber— as bullying behavior, but see only verbal and relational forms as the primary types on campus. Participants also primarily understand immediate micro-system and cultural macro-system influences—including the 2016 U.S. election of President Donald Trump—as impacting bullying behavior. Recommendations for prevention and intervention methods are also discussed.

Committee:

Lisa Pescara-Kovach, Ph.D. (Committee Chair); Gregory Stone, Ph.D. (Committee Member); Robert Salem, J.D. (Committee Member); Florian Feucht, Ph.D. (Committee Member)

Subjects:

Behavioral Psychology; Developmental Psychology; Education; Educational Leadership; Educational Psychology; Educational Sociology; Higher Education; Higher Education Administration

Keywords:

bullying; college student behavior; ecological development

Huang, HuaiModulation of Microtubule Dynamics in Netrin Signaling
Doctor of Philosophy, University of Toledo, 2017, Biology (Cell-Molecular Biology)
Neuronal development proceeds through several stages, such as axon and dendrite differentiation, elongation, branching, and pathfinding. Extracellular guidance cues play an essential role in these processes. Activation of downstream signaling of guidance receptors eventually leads to the cytoskeleton rearrangement. Microtubules (MTs), as one form of the cytoskeleton, play an important role in axon and dendrite outgrowth, elongation and branching. Netrin-1, a canonical guidance molecule, binds to its receptors Deleted in Colorectal Cancer (DCC), Down Syndrome Cell Adhesion Molecule (DSCAM) and uncoordinated-5 (UNC5) mediating neuronal development. Our recent studies have shown that TUBB3, a neuronal ß-tubulin isotype III, directly binds to DCC and Netrin-1 induces this interaction. Results from multiple function assays indicate that TUBB3 is specifically involved in Netrin-1-induced axon outgrowth and guidance. Heterozygous missense mutations in human TUBB3 gene result in a spectrum of brain malformations associated with defects in axon guidance, neuronal migration, and differentiation. However, the molecular mechanisms underlying mutation-related axon guidance abnormalities are unclear. Here, we provide evidence that TUBB3 mutations impair Netrin/DCC signaling in the developing nervous system. The interaction of DCC with most of TUBB3 mutants (eight out of twelve) is significantly reduced compared to the wild type TUBB3. TUBB3 mutants R262C and A302V exhibit decreased subcellular colocalization with DCC in the growth cones of primary neurons. Netrin-1 enhances the interaction of endogenous DCC with wild type human TUBB3, but not with R262C or A302V, in primary neurons. Netrin-1 also increases the co-sedimentation of DCC with polymerized MTs in primary neurons expressing wild type TUBB3, but not R262C or A302V. Expression of either R262C or A302V not only suppresses Netrin-1-induced neurite outgrowth, branching and attraction in vitro, but also causes defects in spinal cord commissural axon projection and pathfinding in ovo. Our study reveals that missense TUBB3 mutations specifically disrupt Netrin/DCC-mediated attractive signaling. MT dynamics play an important role in Netrin-1-promoted axon outgrowth, branching, and axon pathfinding. However, the mechanism by which Netrin-1 regulates this process is not clear. The MT-associated protein (MAP) tau regulates MT stability and dynamics, which are important for neuronal development in the nervous system. Our study shows that tau interacts with the Netrin receptor DCC, and Netrin-1 induces this interaction in primary neurons. Tau colocalizes with DCC in the growth cone of primary neurons and Netrin-1 induces this colocalization. Activation of JNK, GSK-3 and Src family kinases are important for Netrin-1-induced DCC/tau interaction. Knockdown of tau inhibits Netrin-1-induced axon outgrowth, branching and commissural axon attraction in vitro and leads to defects in commissural axon projection in the chick spinal cord in vivo. These findings suggest that tau is involved in Netrin-1 signaling and essential for Netrin-1-promoted neuronal development. In general, these studies are focusing on the role of MT component protein TUBB3 and MT-associated protein tau in the Netrin-1 signaling. The study of TUBB3 mutants further validates the essential role of TUBB3 in Netrin-1-mediated neuronal development by showing that TUBB3 mutants A302V and R262C found in patients disrupt the function of TUBB3 in Netrin-1-mediated neurite outgrowth, axon branching and attraction. The study of tau reveals that tau is involved in Netrin-1-mediated neuronal development. However, the questions regarding the relationship between TUBB3 and tau in Netrin signaling need to be further addressed. For instance, whether Netrin-1 regulates the interaction between tau and TUBB3, and whether the interaction between DCC and tau is dependent upon the presence of TUBB3 need to be clarified.

Committee:

Guofa Liu (Committee Chair); Bruce Bamber (Committee Member); Donald Ronning (Committee Member); Rafael Garcia-Mata (Committee Member); Scott Molitor (Committee Member)

Subjects:

Biology

Capparelli, Amy LAdults’ Reports of Positive and Negative Events and Memory Accuracy for Word Lists During Animal Assisted Interviews
Master of Arts, University of Toledo, 2017, Psychology - Experimental
The use of dogs in child advocacy centers, police departments, and in the courtroom as a means to enhance rapport and facilitate communication with witnesses is increasing. In the current study, we assessed the impact of dogs on the amount that adults reported about negative and positive emotional events. Additionally, we investigated the effect of a dog on memory accuracy for word lists. Undergraduate student participants were randomly assigned to have a dog present (n = 34) or absent (n = 34) while discussing positive and negative experienced events. Following the interview portion of the study, participants were asked to learn word lists designed to create false memories due to strong semantic associations. Participants were given recall and recognition tests to assess their memory for the presented word lists. Based on previous research, it was predicted that the presence of a dog would lead to increased quantity of verbal reports, particularly pertaining negative life events. The results did not support this hypothesis. The analyses revealed no differences in memory performance as a function of dog interview. Explanations for the findings and directions for future research are discussed.

Committee:

Kamala London, Ph.D. (Committee Chair); Jason Rose , Ph.D. (Committee Member); Stephen Christman, Ph.D. (Committee Member)

Subjects:

Psychology

Keywords:

Animal assisted interviews; dogs; false memory

Baker, JessicaPerceptions of World Englishes
Master of Arts, University of Toledo, 2017, English (as a Second Language)
This study looks at how native speakers of English respond to different World Englishes compared to non-native English speakers. Also, it looks at whether people who have more experiences with travel or languages have more positive attitudes towards World English speakers and if they were able to know where a speaker is from. Four native and four non-native participants (eight in total) who were Composition I students were interviewed. Four recordings of various World Englishes were used and participants were asked about their attitudes towards the Englishes. This study found native and non-native participants do not have different attitudes towards World Englishes. It also found that experience did not affect attitudes or abilities identifying World English speakers.

Committee:

Melinda Reichelt (Committee Chair); Anthony Edgington (Committee Member); Muchun Yin (Committee Member)

Subjects:

English As A Second Language; Linguistics

Keywords:

World Englishes

Ingels, Marcel LMechanics of Patellofemoral Maltracking in Total Knee Arthroplasty: A Finite Element Analysis
Master of Science, University of Toledo, 2016, Bioengineering
The patellofemoral joint is a complex joint that accounts for a large percentage of knee problems both in knee arthroplasty and in intact knee mechanics. In the United States alone, a 673% increase in primary total knee arthroplasty surgeries performed per year is projected to occur by 2030 (i.e., 3.48 million procedures). Consequently, the total revision rate per year is also projected to increase by 601% by 2030 (i.e., 268,200 revisions). Complication of the patellofemoral joint, associated with the patella maltracking, is one of the most common reasons for revisions in total knee arthroplasty and anterior pain of the intact knee. Thus, understanding patellofemoral maltracking mechanics and its associated risk factors is necessary. This study developed a validated finite element model of an intact knee to compare with instrumented knee patellar mechanics. The biomechanics of a maltracking patella are complex and have been shown to be associated with patellar subluxation, increased Q-angle, and increased external tibial rotation. These risk factors were applied individually and in combination to both an intact knee model and a knee instrumented with a total knee arthroplasty system to observe their effect on patellar mechanics. Thecombination of risk factors resulted in a worst-case maltracking model that was instrumented with a translating patellar implant with the goal of improving patellofemoral mechanics under maltracking conditions. The results of this study showed that the worst occurrence of patellar maltracking occurs because of a combination of various risk factors, such as patellar subluxation, increased Q-angle, and increased external tibial rotation for both intact and instrumented knees. Of these risk factors, the former contributes substantially more toward inducing non-physiological patellar mechanics than the latter two. Among the kinematic indicators for patellar maltracking in intact knees, medial/lateral patellar translation and tilt were ideal, whereas patellar rotation, although provided valuable insight on the patellofemoral joint kinematics, failed in showing any trend toward patellar maltracking. Among the kinematic indicators for patellar maltracking in instrumented knees, medial/lateral patellar translation was ideal, whereas patellar tilt and rotation, although provided valuable insight on the patellofemoral joint kinematics, failed in showing any trend toward patellar maltracking. Nevertheless, implant designers and clinicians should consider the rotation and tilt of the patella under various physiological conditions as design inputs for devices and conservative treatments. Lastly, the results of this study were used in designing a translating patellar implant that showed to reduce the risk of patellar maltracking, corroborating the value of aforementioned trends and kinematic indicators.

Committee:

Vijay Goel, PhD (Committee Chair); Anand Agarwal, PhD (Committee Member); Ronald Fournier, PhD (Committee Member)

Subjects:

Biomedical Engineering

Porter, Audree ElizabethEffective Topical Delivery of Ibuprofen through the Skin
Master of Science in Pharmaceutical Science (MSP), University of Toledo, 2016, Pharmaceutical Sciences (Industrial Pharmacy)
The ability to effectively deliver non-steroidal anti-inflammatory drugs (NSAIDs) topically and transdermally offers an increased localization of the drug to the site of pain and inflammation, while simultaneously reducing systemic absorption. This ultimately results in more effective treatment for localized pain and inflammation, while reducing the undesired side effects associated with NSAIDs. In this work, effective topical delivery was studied, specifically to compare and contrast the effects of three separate penetration enhancers utilizing in vitro Franz cell testing methods. Ten formulations, using three different penetration enhancers (Kollicream OA, Kollicream IPM and Kollicream 3C) and two different active pharmaceutical ingredients (ibuprofen and sodium ibuprofen), were tested and results are given in this report. Ultimately, the penetration enhancers were found to impede delivery of active pharmaceutical drugs into the epidermis of the skin over an 8-hour period as compared to a standard blank cream run concurrently. Kollicream 3C was shown to have the best release profile over the initial first hour of the study, mimicking the initial application of the pharmaceutical product. Kollicream OA was shown to have the best release profile over the entire 8-hour period.

Committee:

Kenneth Alexander, Ph.D (Committee Chair); Gabriella Baki, Ph.D. (Committee Member); Marcia McInerney, Ph.D. (Committee Member)

Subjects:

Pharmaceuticals

Keywords:

Penetration Enhancer; Ibuprofen; Topical Drug Delivery

Penumatsa, GowthamCorrosion Detection in Reinforced Concrete Using Acoustic Emission Technique
Master of Science, University of Toledo, 2016, Civil Engineering
Corrosion of reinforcing steel is the major cause for deterioration of concrete structures. Corrosion of these steel bars potentially reduces the service life and ductility of the structures causing early failure of structure, this involves signifi cant cost for inspection and maintenance. Early detection of corrosion is necessary for the proper diagnosis and effective prevention of failure. Therefore, damage induced due to corrosion of reinforcing steel should be detected in the early stages and the severity of corrosion should be properly anticipated by means of non-destructive testing techniques for the safety of the structure. The available methods of corrosion detection in concrete structures are generally electrochemical, such as half-cell potential (HCP) measurements and linear polarization resistance (LPR). These methods are intrusive as they require a physical connection to the corroding steel. Furthermore, these methods only provide information about local corrosion and are usually used after corrosion damage is discovered visually. Acoustic emission is sensitive enough to be a feasible nondestructive testing technique to detect early corrosion. Therefore a corrosion monitoring cell to detect corrosion in reinforced concrete beams using acoustic emission is setup for the rst time at The University of Toledo and experiments are conducted. This thesis presents the fi rst use of acoustic emission to detect corrosion in rein- forced concrete at The University of Toledo. The tasks accomplished includes setting up a corrosion cell and understanding the AE hardware and software equipment. A literature review of corrosion monitoring in reinforced concrete using acoustic emission technology is provided in order to understand the AE technology advancement to date. Corrosion monitoring experiments were designed in the laboratory to initiate corrosion in reinforced concrete in a short time span and continuously monitor with an AE data acquisition system. Electrochemical half-cell potential method is used to anticipate the initiation of corrosion and to correlate AE data with potentials at di fferent stages of the experiment. Steel rebar and two reinforced concrete beams are corroded immersing in 3.5% NaCl solution and using constant potential. The corrosion in these rebar and concrete specimens are monitored continuously using Mistras Pocket Corpac with R15 sensors. Half cell potential measurements are also conducted to understand the method and used to establish correlation with AE. The experiments conducted helped to understand the corrosion process and detect corrosion using AE. The results of the experiments using acoustic emission were found consistent with those in the literature and the conclusions were con rmed using half- cell potential measurements.

Committee:

Douglas Nims (Advisor); Liangbo Hu (Committee Member); Dong Kim (Committee Member)

Subjects:

Civil Engineering; Engineering

Walsh, SeanPerformance-Based Assessment of Oral Dependency within a Forensic Inpatient Mental Health Population
Doctor of Philosophy, University of Toledo, 2016, Psychology - Clinical
The impact of interpersonal dependency can be easily overlooked in clinical and forensic populations despite significant associations with elevated risk for physical illness, suicidality, and functional impairment (Bornstein, 2012). While many measures of interpersonal dependency have been developed and validated across a wide range of clinical populations, there has been minimal research regarding measures appropriate for forensic inpatient mental health populations. The Oral Dependency Language (ODL) scale from the Rorschach Performance Assessment System (R-PAS; Meyer, Viglione, Mihura, Erard, & Erdberg, 2011) is a widely used and validated performance-based measure of interpersonal dependency, but only one published study has used this scale in a forensic population. The present investigation evaluates how dependency needs might manifest within a forensic inpatient mental health population by comparing ODL scores from 88 patients admitted to a maximum security forensic psychiatric facility with ratings of uncooperativeness and passive social withdrawal from the Positive and Negative Syndrome Scale (PANSS; Kay, Fiszbein, & Opler, 1987), a clinician-rated measure of symptoms associated with schizophrenia.Significant negative correlations between ODL scores and the uncooperativeness and passive social withdrawal PANSS items were anticipated but not found. Second, this study also attempted to replicate past research showing a relationship between dependency and physical illness (Bornstein, 1998), with significant positive correlations being expected but not found. Finally, analyses attempted to (a) replicate past research identifying elevated levels of dependency in non-violent pedophiles and sexual homicide perpetrators and (b) extend this research by looking at the relationship between dependency and instant offenses that capture manifestations of orality. Significant positive correlations were hypothesized for both of these analyses but were not found. Lack of construct fit with PANSS variables, method of measurement for assessing dependency, the influence of psychosis on instant offenses, and unique manifestations of dependency in a forensic inpatient mental health population with patients experiencing psychosis are discussed as possible reasons for the lack of significant results for the current study.

Committee:

Joni Mihura, Ph.D. (Committee Chair); Gregory Meyer, Ph.D. (Committee Member); Wesley Bullock, Ph.D. (Committee Member); Jason Rose, Ph.D. (Committee Member); Nicole Kletzka, Ph.D. (Committee Member)

Subjects:

Clinical Psychology; Psychological Tests; Psychology

Keywords:

Dependency, Rorschach, R-PAS, Schizophrenia, PANSS, Forensic, Assessment

Sigdel, PawanImproving Design Strategies for Composite Pavement Overlay: Multi-layered Elastic Approach and Reliability Based Models
Doctor of Philosophy, University of Toledo, 2016, Civil Engineering
Pavements need constant rehabilitation when they deteriorate with time and approach the end of their expected service lives. Overlay is the most prevalent treatment that restores its desirable condition and extends its life span of serviceability, especially for roads subjected to moderate and heavy traffic. Overlay composite design remains a major challenge due to difficulties in characterizing the complex behavior and assessing the existing condition of a combination of asphalt concrete (AC) and Portland cement concrete (PCC) layers over a soil subgrade. Deflection based design using falling weight deflectometer (FWD) deflection data offers an effective approach for overlay thickness design for composite pavements. It utilizes the deflection measurements of the pavement surface which can be used to back-calculate the subgrade and overlay composite properties and allows one to estimate the structural capacity of the existing pavement. However, the prevailing deflection based design procedure generally treats the AC and PCC as a single layer during the back-calculation and, as a result, frequently leads to less than satisfactory, usually over-conservative, design for overlay composites. The principal objective of this research is to develop improved FWD deflection based design strategies for overlay composite pavements. It is proposed that a three-layer linear elastic model be used for back-calculation of the moduli of all three layers: subgrade, PCC and AC. The structural capacity of the existing pavement is estimated using pavement surface deflections measured by FWD, the most commonly used pavement non-destructive testing (NDT) device. In the present study actual FWD deflection data for eleven construction projects are used to back-calculate the moduli of three layers. The three-layer model allows the composite pavement structure to be modeled more accurately. The elastic moduli of the asphalt concrete layer and the underlying Portland cement concrete can both be back-calculated, instead of combining them into one. The results show that the three-layer model produces higher effective thickness than the two-layer model for the same pavement structure, thereby reducing the required overlay thickness. However, there are a number of factors that can strongly influence the final overlay design thickness. The effects of computational error tolerances in back-calculation, temperature at FWD testing and variations in FWD deflection data are found significant and may cause unreliable design results and hence, two strategies to avoid excessively large or small back-calculated moduli are also explored: imposing moduli bounds and relaxing the precision convergence; they have been found very effective in mitigating the effect of large variations in deflection data. The statistical variations observed in the overlay design are also evaluated and two models are explored to improve the overall design procedure from the statistical perspective: Monte Carlo method and Point Estimation method. The effective thicknesses of existing pavement computed from reliability analysis are similar to those obtained from the proposed design method. This demonstrates the validity of the proposed design method and also the applicability of reliability based design in case the statistical parameters are available or can be obtained from engineering judgement.

Committee:

Liangbo Hu (Committee Chair); Eddie Chou (Committee Member); Brian Randolph (Committee Member); Youngwoo Seo (Committee Member); Habib Kaake (Committee Member)

Subjects:

Civil Engineering

Keywords:

composite pavement, overlay design, reliability, temperature correction

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