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- Title
- Energy Expenditure and Stability During Self-Paced Walking on Different Slopes.
- Creator
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Raffaelli, Alanna, Huang, Helen, Fu, Qiushi, Kassab, Alain, University of Central Florida
- Abstract / Description
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Metabolic power and cost of transport (COT) are common quantifiers for effort when performing tasks including walking and running. Most studies focus on using a range of normal walking speeds over level ground or varied slopes. However, these studies use fixed-speed conditions. Fatigue, stability, metabolic expenditure, heart rate, and many other factors contribute to normal walking speed varying over time. This study aimed to show that allowing a subject to walk with a self-paced speed...
Show moreMetabolic power and cost of transport (COT) are common quantifiers for effort when performing tasks including walking and running. Most studies focus on using a range of normal walking speeds over level ground or varied slopes. However, these studies use fixed-speed conditions. Fatigue, stability, metabolic expenditure, heart rate, and many other factors contribute to normal walking speed varying over time. This study aimed to show that allowing a subject to walk with a self-paced speed should correlate to a minimum COT at a given slope. This study also aimed to determine if a preferred slope exists based on minimizing metabolic expenditure or maximizing stability. In this study, subjects walked at four different speed conditions including three fixed speeds (0.75 m/s, 1.0 m/s, 1.25 m/s) and their self-paced speed at five different slopes (-6(&)deg;, -3(&)deg;, 0(&)deg;, 3(&)deg;, 6(&)deg;) while metabolic energy expenditure and motion were recorded. The minimum COT occurred at a 3(&)deg; decline. At this slope, some subjects preferred to walk at a faster speed compared to level ground, whereas other subjects walked with a slower speed compared to level ground. Thus, there was a greater range of self-paced speeds, from 0.745 m/s-2.045 m/s. In comparison, at a 6(&)deg; incline, the range of self-paced speeds was much smaller, from 0.767 m/s-1.434 m/s. The variance among self-paced speeds and slope conditions between subjects suggests that COT, alone, does not explain walking decisions; stability might play a greater role than initially believed. These results provide greater insight into why humans choose to walk at a certain speed over a range of slopes and terrains.
Show less - Date Issued
- 2019
- Identifier
- CFE0007515, ucf:52629
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007515
- Title
- Electrochemical Microsensors for In Situ Monitoring of Chemical Compounds in Engineered and Natural Aquatic Systems.
- Creator
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Church, Jared, Lee, Woo Hyoung, Randall, Andrew, Duranceau, Steven, University of Central Florida
- Abstract / Description
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The adaption of needle-type electrochemical microsensor (or microelectrode) techniques to environmental science and engineering systems has transformed how we understand mass transport in biotic and abiotic processes. Their small tip diameter (5-20(&)#181;m) makes them a unique experimental tool for direct measurements of analytes with high spatial and temporal resolutions, providing a quantitative analysis of flux, diffusion, and reaction rate at a microscale that cannot be obtained using...
Show moreThe adaption of needle-type electrochemical microsensor (or microelectrode) techniques to environmental science and engineering systems has transformed how we understand mass transport in biotic and abiotic processes. Their small tip diameter (5-20(&)#181;m) makes them a unique experimental tool for direct measurements of analytes with high spatial and temporal resolutions, providing a quantitative analysis of flux, diffusion, and reaction rate at a microscale that cannot be obtained using conventional analytical tools. However, their applications have been primarily limited to understanding mass transport dynamics and kinetics in biofilms. With the advancement of sensor fabrication and utilization techniques, their potential applications can surpass conventional biofilm processes. In this dissertation, microsensors were utilized to elucidate mass transport and chemical reactions in multidisciplinary research areas including biological nutrient uptake, oily wastewater treatment, photocatalytic disinfection, and plant disease management, which have not yet explored using this emerging technology. The main objective of this work was to develop novel microsensors and use them for better understanding various natural and engineered aquatic systems. These include; 1) investigating localized photo-aeration and algal-bacterial symbiotic interaction in an advanced algal-bacterial biofilm process for nutrient removal from wastewater, 2) characterizing oil-in-water emulsions for better understanding bilge water emulsion stability, 3) evaluating sun-light driven photocatalytic reactions using a novel MoS2 nanofilm for water disinfection and microcystins-LR removal, 4) developing a zinc ion-selective microsensor and applying them for monitoring the transport of zinc in citrus trees, and 5) integrating heavy metal detection using anodic stripping voltammetry (ASV) in a microelectrode platform for plant applications.
Show less - Date Issued
- 2018
- Identifier
- CFE0007565, ucf:52576
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007565
- Title
- Florida's Paradox of Progress: An Examination of the Origins, Construction, and Impact of the Tamiami Trail.
- Creator
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Schellhammer, Mark, Lester, Connie, Sacher, John, Larson, Peter, University of Central Florida
- Abstract / Description
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This study illustrates the impact of the Tamiami Trail on the people and environment of South Florida through an examination of the road's origins, construction and implementation. By exploring the motives behind building the highway, the subsequent assimilation of indigenous societies, the drastic population growth that occurred as a result of a propagated (")Florida Dream("), and the environmental decline of the surrounding Everglades, this analysis reveals that the Tamiami Trail is viewed...
Show moreThis study illustrates the impact of the Tamiami Trail on the people and environment of South Florida through an examination of the road's origins, construction and implementation. By exploring the motives behind building the highway, the subsequent assimilation of indigenous societies, the drastic population growth that occurred as a result of a propagated (")Florida Dream("), and the environmental decline of the surrounding Everglades, this analysis reveals that the Tamiami Trail is viewed today through a much different context than that of the road's builders and promoters in the early twentieth century. While construction projects that aim to prevent, or limit the once celebrated environmental destruction caused by the Tamiami Trail, the unrelenting and economically stimulating growth of South Florida continues to uncover a (")paradox of progress.(")
Show less - Date Issued
- 2012
- Identifier
- CFE0004597, ucf:49186
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004597
- Title
- Macroscopic Crash Analysis and Its Implications for Transportation Safety Planning.
- Creator
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Siddiqui, Chowdhury, Abdel-Aty, Mohamed, Abdel-Aty, Mohamed, Uddin, Nizam, Huang, Helai, University of Central Florida
- Abstract / Description
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Incorporating safety into the transportation planning stage, which is often termed as transportation safety planning (TSP), relies on the vital interplay between zone characteristics and zonal traffic crashes. Although a few safety studies had made some effort towards integrating safety and planning, several unresolved problems and a complete framework of TSP are still absent in the literature. This research aims at examining the suitability of the current traffic-related zoning planning...
Show moreIncorporating safety into the transportation planning stage, which is often termed as transportation safety planning (TSP), relies on the vital interplay between zone characteristics and zonal traffic crashes. Although a few safety studies had made some effort towards integrating safety and planning, several unresolved problems and a complete framework of TSP are still absent in the literature. This research aims at examining the suitability of the current traffic-related zoning planning process in a new suggested planning method which incorporates safety measures. In order to accomplish this broader research goal, the study defined its research objectives in the following directions towards establishing a framework of TSP- i) exploring the existing key determinants in traditional transportation planning (e.g., trip generation/distribution data, land use types, demographics, etc.) in order to develop an effective and efficient TSP framework, ii) investigation of the Modifiable Aerial Unit Problem (MAUP) in the context of macro-level crash modeling to investigate the effect of the zone's size and boundary, iii) understanding neighborhood influence of the crashes at or near zonal boundaries, and iv) development of crash-specific safety measure in the four-step transportation planning process.This research was conducted using spatial data from the counties of West Central Florida. Analysis of different crash data per spatial unit was performed using nonparametric approaches (e.g., data mining and random forest), classical statistical methods (e.g., negative binomial models), and Bayesian statistical techniques. In addition, a comprehensive Geographic Information System (GIS) based application tools were utilized for spatial data analysis and representation.Exploring the significant variables related to specific types of crashes is vital in the planning stages of a transportation network. This study identified and examined important variables associated with total crashes and severe crashes per traffic analysis zone (TAZ) by applying nonparametric statistical techniques using different trip related variables and road-traffic related factors. Since a macro-level analysis, by definition, will necessarily involve aggregating crashes per spatial unit, a spatial dependence or autocorrelation may arise if a particular variable of a geographic region is affected by the same variable of the neighboring regions. So far, few safety studies were performed to examine crashes at TAZs and none of them explicitly considered spatial effect of crashes occurring in them. In order to understand the clear picture of spatial autocorrelation of crashes, this study investigated the effect of spatial autocorrelation in modeling pedestrian and bicycle crashes in TAZs. Additionally, this study examined pedestrian crashes at Environmental Justice (EJ) TAZs which were identified in compliance with the various ongoing practices undertaken by Metropolitan Planning Organizations (MPOs) and previous research. Minority population and the low-income group are two important criteria based on which EJ areas are being identified. These unique areal characteristics have been of particular interest to the traffic safety analysts in order to investigate the contributing factors of pedestrian crashes in these deprived areas. Pedestrian and bicycle crashes were estimated as a function of variables related to roadway characteristics, and various demographic and socio-economic factors. It was found that significant differences are present between the predictor sets for pedestrian and bicycle crashes. In all cases the models with spatial correlation performed better than the models that did not account for spatial correlation among TAZs. This finding implied that spatial correlation should be considered while modeling pedestrian and bicycle crashes at the aggregate or macro-level. Also, the significance of spatial autocorrelation was later found in the total and severe crash analyses and accounted for in their respective modeling techniques.Since the study found affirmative evidence about the inclusion of spatial autocorrelation in the safety performance functions, this research considered identifying appropriate spatial entity based on which TSP framework would be developed. A wide array of spatial units has been explored in macro-level crash modeling in previous safety research. With the advancement of GIS, safety analysts are able to analyze crashes for various geographical units. However, a clear guideline on which geographic entity should a modeler choose is not present so far. This preference of spatial unit can vary with the dependent variable of the model. Or, for a specific dependent variable, models may be invariant to multiple spatial units by producing a similar goodness-of-fits. This problem is closely related to the Modifiable Areal Unit Problem which is a common issue in spatial data analysis. The study investigated three different crash (total, severe, and pedestrian) models developed for TAZs, block groups (BGs) and census tracts (CTs) using various roadway characteristics and census variables (e.g., land use, socio-economic, etc.); and compared them based on multiple goodness-of-fit measures.Based on MAD and MSPE it was evident that the total, severe and pedestrian crash models for TAZs and BGs had similar fits, and better than the ones developed for CTs. This indicated that the total, severe and pedestrian crash models are being affected by the size of the spatial units rather than their zoning configurations. So far, TAZs have been the base spatial units of analyses for developing travel demand models. Metropolitan planning organizations widely use TAZs in developing their long range transportation plans (LRTPs). Therefore, considering the practical application it was concluded that as a geographical unit, TAZs had a relative ascendancy over block group and census tract.Once TAZs were selected as the base spatial unit of the TSP framework, careful inspections on the TAZ delineations were performed. Traffic analysis zones are often delineated by the existing street network. This may result in considerable number of crashes on or near zonal boundaries. While the traditional macro-level crash modeling approach assigns zonal attributes to all crashes that occur within the zonal boundary, this research acknowledged the inaccuracy resulting from relating crashes on or near the boundary of the zone to merely the attributes of that zone. A novel approach was proposed to account for the spatial influence of the neighboring zones on crashes which specifically occur on or near the zonal boundaries. Predictive model for pedestrian crashes per zone were developed using a hierarchical Bayesian framework and utilized separate predictor sets for boundary and interior (non-boundary) crashes. It was found that these models (that account for boundary and interior crashes separately) had better goodness-of-fit measures compared to the models which had no specific consideration for crashes located at/near the zone boundaries. Additionally, the models were able to capture some unique predictors associated explicitly with interior and boundary-related crashes. For example, the variables- 'total roadway length with 35mph posted speed limit' and 'long term parking cost' were statistically not significantly different from zero in the interior crash model but they were significantly different from zero at the 95% level in the boundary crash model.Although an adjacent traffic analysis zones (a single layer) were defined for pedestrian crashes and boundary pedestrian crashes were modeled based on the characteristic factors of these adjacent zones, this was not considered reasonable for bicycle-related crashes as the average roaming area of bicyclists are usually greater than that of pedestrians. For smaller TAZs sometimes it is possible for a bicyclist to cross the entire TAZ. To account for this greater area of coverage, boundary bicycle crashes were modeled based on two layers of adjacent zones. As observed from the goodness-of-fit measures, performances of model considering single layer variables and model considering two layer variables were superior from the models that did not consider layering at all; but these models were comparable. Motor vehicle crashes (total and severe crashes) were classified as 'on-system' and 'off-system' crashes and two sub-models were fitted in order to calibrate the safety performance function for these crashes. On-system and off-system roads refer to two different roadway hierarchies. On-system or state maintained roads typically possess higher speed limit and carries traffic from distant TAZs. Off-system roads are, however, mostly local roads with relatively low speed limits. Due to these distinct characteristics, on-system crashes were modeled with only population and total employment variables of a zone in addition to the roadway and traffic variables; and all other zonal variables were disregarded. For off-system crashes, on contrary, all zonal variables was considered. It was evident by comparing this on- and off-system sub-model-framework to the other candidate models that it provided superior goodness-of-fit for both total and severe crashes.Based on the safety performance functions developed for pedestrian, bicycle, total and severe crashes, the study proposed a novel and complete framework for assessing safety (of these crash types) simultaneously in parallel with the four-step transportation planning process with no need of any additional data requirements from the practitioners' side.
Show less - Date Issued
- 2012
- Identifier
- CFE0004191, ucf:49009
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004191
- Title
- Sustainable Transportation at the University of Central Florida: Evaluation of UCF Rideshare Program, Zimride.
- Creator
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Defrancisco, Joseph, Radwan, Ahmed, Abdel-Aty, Mohamed, Harb, Rami, University of Central Florida
- Abstract / Description
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As the second-largest university in the United States, UCF has experienced the largest enrollment in its history. A more densely populated campus has in turn caused increased traffic congestion. Despite increased parking permit fees and newly constructed parking garages, traveling and parking on campus is unpredictable. In effort to reduce congestion on campus, a rideshare program was implemented in Summer 2010. Several universities across the nation have successfully used carpooling as a...
Show moreAs the second-largest university in the United States, UCF has experienced the largest enrollment in its history. A more densely populated campus has in turn caused increased traffic congestion. Despite increased parking permit fees and newly constructed parking garages, traveling and parking on campus is unpredictable. In effort to reduce congestion on campus, a rideshare program was implemented in Summer 2010. Several universities across the nation have successfully used carpooling as a viable alternative mode to manage traffic and parking demand. This thesis evaluates the UCF rideshare program, Zimride, using stated- and revealed-preference surveys. Preliminary results indicate most students prefer to commute to campus using their own car and without incentives there is no reason to change mode choice, regardless of associated costs(-)e.g. decal cost, parking time and frustration. Despite 70% of respondents considering themselves environmentally friendly and over 80% are aware of savings in money and productive by using alternative modes, 70% still use their car to commute to campus. Using Explanatory Factor Analysis (EFA) and Structural Equation Modeling (SEM), the observed variables were organized into three (3) latent variables based on the correlation among them. The SEM results of the revealed-preference survey indicate current travel behavior significantly influences attitudes towards carpooling and demographics have a significant effect on current travel behavior. It was also found that demographics influences attitudes towards carpooling at a non statistically significant level.
Show less - Date Issued
- 2012
- Identifier
- CFE0004226, ucf:48996
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004226
- Title
- THE CRIME OF COMING HOME: BRITISH CONVICTS RETURNING FROM TRANSPORTATION IN LONDON, 1720-1780.
- Creator
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Teixeira, Christopher, Beiler, Rosalind, University of Central Florida
- Abstract / Description
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This thesis examines convicts who were tried for the crime of ÂÂ"returning from transportationÂÂ" at LondonÂÂ's Old Bailey courthouse between 1720 and 1780. While there is plenty of historical scholarship on the tens of thousands of people who endured penal transportation to the American colonies, relatively little attention has been paid to convicts who migrated illegally back to Britain or those who avoided banishment altogether....
Show moreThis thesis examines convicts who were tried for the crime of ÂÂ"returning from transportationÂÂ" at LondonÂÂ's Old Bailey courthouse between 1720 and 1780. While there is plenty of historical scholarship on the tens of thousands of people who endured penal transportation to the American colonies, relatively little attention has been paid to convicts who migrated illegally back to Britain or those who avoided banishment altogether. By examining these convicts, we can gain a better understanding of how transportation worked, how convicts managed to return to Britain, and most importantly, what happened to them there. This thesis argues that convicts resisted transportation by either avoiding it or returning from banishment after obtaining their freedom. However, regardless of how they arrived back in Britain, many failed to reintegrate successfully back into British society, which led to their apprehension and trial. I claim that most convicts avoided the death penalty upon returning and that this encouraged more convicts to resist transportation and return home. The thesis examines the court cases of 132 convicts charged with returning from transportation at the Old Bailey and examines this migration home through the eyes of those who experienced it. First, the thesis focuses on convicts in Britain and demonstrates how negative perceptions of transportation encouraged them to resist banishment. The thesis then highlights how convicts obtained their freedom in the colonies, which gave them the opportunity to return illegally. Finally, the thesis shows that returned felons tried to reintegrate into society by relocating to new cities, leading quiet honest lives, or by returning to a life of crime.
Show less - Date Issued
- 2010
- Identifier
- CFE0003105, ucf:48297
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003105
- Title
- HUNGRY AND TAKING THE BUS? ASSESSING FOOD OUTLET ACCESSIBILITY IN CENTRAL FLORIDA.
- Creator
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Smith, Katelan, Wright, James, University of Central Florida
- Abstract / Description
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Little academic research has been conducted examining access to transportation by those in need. The small amount of research that has been done focuses primarily on mobility issues of the elderly and the disabled, despite findings that income level is an important determinant in access to transportation. The few studies that have examined access to transportation in relation to income simply cite the difficulties that those in poverty face when attempting to access vital resources as...
Show moreLittle academic research has been conducted examining access to transportation by those in need. The small amount of research that has been done focuses primarily on mobility issues of the elderly and the disabled, despite findings that income level is an important determinant in access to transportation. The few studies that have examined access to transportation in relation to income simply cite the difficulties that those in poverty face when attempting to access vital resources as problematic, yet very few focus specifically on this issue. This thesis examines how free food recipients commute to and from local pantries, and whether public transportation in the Orlando metropolitan area adequately services food bank resources utilized by low income individuals. Physical location data as well as survey questionnaires were used to determine commuting patterns as well as the overall availability and utilization of transit options of Orlando's low income population. Findings from this study show that even though nearly 50% of respondents do not own a car, public transportation remains a last option, making the Orlando area heavily dependent on cars, even for those with no direct access to one. Despite low public transit ridership, it was found that the majority of food pantries in Orange County are adequately serviced by LYNX, while pantries in Seminole County suffer from a severe lack of services.
Show less - Date Issued
- 2011
- Identifier
- CFE0003913, ucf:48757
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003913
- Title
- The behavior of humans and wildlife with respect to roads: insights for mitigation and management.
- Creator
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Grace, Molly, Noss, Reed, Weishampel, John, Hoffman, Eric, Johnson, Steve, University of Central Florida
- Abstract / Description
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Road ecology is the study of how roads and wildlife interact. Traditionally, road ecologists have primarily focused on one effect of roads: roadkill. Though roadkill can have devastating effects on wildlife populations, roads have sub-lethal impacts that are gaining more and more attention from the scientific community. These sub-lethal impacts include noise, light, and chemical pollution as well as altered habitat structure, which can all influence animal behavior. In this dissertation, I...
Show moreRoad ecology is the study of how roads and wildlife interact. Traditionally, road ecologists have primarily focused on one effect of roads: roadkill. Though roadkill can have devastating effects on wildlife populations, roads have sub-lethal impacts that are gaining more and more attention from the scientific community. These sub-lethal impacts include noise, light, and chemical pollution as well as altered habitat structure, which can all influence animal behavior. In this dissertation, I applied a behavioral ecology framework to study specific lethal and sub-lethal road effects with the goal of improving mitigation efforts. In Chapters 1 and 2, I evaluated how human behavior may be modified to reduce wildlife-vehicle collisions; traditionally efforts have been made to modify wildlife road crossing behavior. I found that Roadside Animal Detection Systems, which warn drivers when animals are near the road, are successful in reducing crash risk; however, care must be taken to ensure that drivers do not become acclimated to the warning system. In Chapters 3 and 4, I evaluated how traffic noise affects subadult growth and adult abundance and communication of anuran amphibians (frogs and toads), a taxon widely recognized as one of the most negatively impacted by roads. I found that through traffic noise alters tadpole behavior, it does not appear to have a negative effect on their growth. Traffic noise does, however, negatively affect adult anuran abundance. My results indicate that this reduction in abundance is caused by the interference of traffic noise with anuran communication.
Show less - Date Issued
- 2017
- Identifier
- CFE0006595, ucf:51275
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006595
- Title
- Investigation of Optical and Electronic Properties of Au Decorated MoS2.
- Creator
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Bhanu, Udai, Khondaker, Saiful, Leuenberger, Michael, Zhai, Lei, University of Central Florida
- Abstract / Description
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Achieving tunability of two dimensional (2D) transition metal dichalcogenides (TMDs) functions calls for the introduction of hybrid 2D materials by means of localized interactions with zero dimensional (0D) materials. A metal-semiconductor interface, as in gold (Au) - molybdenum disulfide (MoS2), is of great interest from the standpoint of fundamental science as it constitutes an outstanding platform to investigate optical and electronic properties due to charge transfer. The applied aspects...
Show moreAchieving tunability of two dimensional (2D) transition metal dichalcogenides (TMDs) functions calls for the introduction of hybrid 2D materials by means of localized interactions with zero dimensional (0D) materials. A metal-semiconductor interface, as in gold (Au) - molybdenum disulfide (MoS2), is of great interest from the standpoint of fundamental science as it constitutes an outstanding platform to investigate optical and electronic properties due to charge transfer. The applied aspects of such systems introduce new options for electronics, photovoltaics, detectors, catalysis, and biosensing. Here in this dissertation, we study the charge transfer interaction between Au nanoparticals and MoS2 flakes and its effect on Photoluminescence and electronic transport properties. The MoS2 was mechanically exfoliated from bulk single crystal. Number of layers in the flake was identified with the help of AFM and Raman Spectra. Au was deposited by physical vapor deposition method (PVD) in multiple steps to decorate MoS2 flakes.We first study the photoluminescence of pristine and Au decorated MoS2 and shows that in the presence of Au, the photoluminescence of MoS2 quenches significantly. We infer that the PL quenching can be attributed to a change in the electronic structure of the MoS2-Au system. The difference in Fermi level of a of MoS2 and Au results in a 0.4 eV energy level offset, which causes a band bending in the MoS2-Au hybrid. Upon illumination, the electrons in the excited state of MoS2 transfer to Au, leaving a hole behind, thus cause p-doping in MoS2. As electrons from MoS2 are transferred to Au, they do not decay back to their initial ground state, leading to PL quenching in the hybrid system.ivTo study the effect of Au deposition on electronic properties of ultra-thin and multilayers MoS2 flakes, we have fabricated MoS2 FETs from (1) ultra-thin sample (2-4 MoS2 layers) and (2) multilayers samples (more than 20 layers). After each deposition of Au, we measured the electrical characteristics of FET at room temperature. We show that the threshold voltage shifts towards the positive gate voltage as we increase the thickness of Au. This shift in threshold voltage is indicative of p doping of the MoS2. We further show that the field effect mobility of MoS2 FET decrease with Au thickness. We have quantitatively estimated the charge transferring from MoS2 to Au.
Show less - Date Issued
- 2015
- Identifier
- CFE0006025, ucf:51013
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006025
- Title
- Electronic Transport Investigation of Chemically Derived Reduced Graphene Oxide Sheets.
- Creator
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Joung, Daeha, Khondaker, Saiful, Chow, Lee, Leuenberger, Michael, Zhai, Lei, University of Central Florida
- Abstract / Description
-
Reduced graphene oxide (RGO) sheet, a chemically functionalized atomically thin carbon sheet, provides a convenient pathway for producing large quantities of graphene via solution processing. The easy processibility of RGO sheet and its composites offer interesting electronic, chemical and mechanical properties that are currently being explored for advanced electronics and energy based materials. However, a clear understanding of electron transport properties of RGO sheet is lacking which is...
Show moreReduced graphene oxide (RGO) sheet, a chemically functionalized atomically thin carbon sheet, provides a convenient pathway for producing large quantities of graphene via solution processing. The easy processibility of RGO sheet and its composites offer interesting electronic, chemical and mechanical properties that are currently being explored for advanced electronics and energy based materials. However, a clear understanding of electron transport properties of RGO sheet is lacking which is of great significance for determining its potential application. In this dissertation, I demonstrate fabrication of high-yield solution based graphene field effects transistor (FET) using AC dielectrophoresis (DEP) and investigate the detailed electronic transport properties of the fabricated devices. The majority of the devices show ambipolar FET properties at room temperature. However, the mobility values are found to be lower than pristine graphene due to a large amount of residual defects in RGO sheets. I calculate the density of these defects by analyzing the low temperature (295 to 77K) charge transport data using space charge limited conduction (SCLC) with exponential trap distribution. At very low temperature (down to 4.2 K), I observe Coulomb blockade (CB) and Efros-Shklovskii variable range hopping (ES VRH) conduction in RGO implying that RGO can be considered as a graphene quantum dots (GQD) array, where graphene domains act like QDs while oxidized domains behave like tunnel barriers between QDs. This was further confirmed by studying RGO sheets of varying carbon sp2 fraction from 55 (-) 80 % and found that both the localization length and CB can be tuned. From the localization length and using confinement effect, we estimate tunable band gap of RGO sheets with varying carbon sp2 fraction. I then studied one dimensional RGO nanoribbon (RGONR) and found ES VRH and CB models are also applicable to the RGONR. However, in contrast to linear behavior of decrease in threshold voltage (Vt) with increasing temperature (T) in the RGO, sub linear dependence of Vt on T was observed in RGONR due to reduced transport pathways. Finally, I demonstrate synthesis and transport studies of RGO/nanoparticles (CdS and CeO2) composite and show that the properties of RGO can be further tuned by attaching the nanoparticles.
Show less - Date Issued
- 2012
- Identifier
- CFE0004785, ucf:49743
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004785
- Title
- Design, Synthesis, and Biological Evaluation of Novel Polyamine Transport System Probes and their Application to Human Cancers.
- Creator
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Muth, Aaron, Phanstiel, Otto, Ye, Jingdong, Elsheimer, Seth, Miles, Delbert, Vonkalm, Laurence, University of Central Florida
- Abstract / Description
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The mammalian polyamine transport system (PTS) has been of interest due to its roles in cancer and maintaining cellular homeostasis. Polyamines are essential growth factors which are tightly controlled via a balance of biosynthesis, metabolism, import, and export. This work focused on the development and biological testing of polyamine transport probes to help understand the molecular requirements of the PTS. This was mediated through the use of a CHO (PTS active) and CHO-MG* (PTS deficient)...
Show moreThe mammalian polyamine transport system (PTS) has been of interest due to its roles in cancer and maintaining cellular homeostasis. Polyamines are essential growth factors which are tightly controlled via a balance of biosynthesis, metabolism, import, and export. This work focused on the development and biological testing of polyamine transport probes to help understand the molecular requirements of the PTS. This was mediated through the use of a CHO (PTS active) and CHO-MG* (PTS deficient) screen, where compounds demonstrating high toxicity in CHO and low toxicity in CHO-MG* were considered PTS selective. The first chapter focused on the development of polyamine-based drugs which are both metabolically stable to polyamine oxidase (PAO) activity and are hyperselective for targeting the PTS. This approach was optimized by combining a di-substituted aryl design with terminal N-methylation of the appended polyamine chains to generate a new class of superior PTS agonists. The metabolic stability of these compounds was demonstrated in CHO and CHO-MG* in the presence and absence of a known PAO inhibitor, aminoguanidine (AG). Highly PTS selective compounds were then tested in the NCI-60 cell line screen to demonstrate the effectiveness of polyamine-based drugs in cancer therapy. During this screen, the MALME-3M (human melanoma) cell line was identified as being very sensitive to these PTS targeting drugs. Further studies using MALME-3M and its normal counterpart, MALME-3, showed excellent targeting of the cancer line over MALME-3. For example, The MeN44Nap44NMe compound showed 59-fold higher toxicity in MALME-3M over MALME-3.The second chapter focused on the development of potential polyamine transport inhibitors (PTIs) for use in combination therapy with ?-difluoromethylornithine (DFMO). This therapy is predicated upon reducing sustained polyamine depletion within cells by inhibiting both polyamine biosynthesis with DFMO and polyamine transport with the PTI ligand. Potential PTIs were identified by blocking the uptake of spermidine in DFMO-treated CHO and L3.6pl cells. Previous work has identified a tri-substituted polyamine-based design as an effective PTI. Low toxicity and a low Ki value in a L1210 screen were good predictors for PTI efficacy. The structural requirements for a potent PTI were explored by modulating the toxicity through the introduction of amide bonds, and also by determining the number and orientation of the polyamine messages (appended to an aryl core) required for efficient inhibition of polyamine uptake. These experiments showed that a tri-substituted design and a triamine message (homospermidine) appended was optimal for PTI potency. The final chapter focused on the development of Dihydromotuporamine C derivatives as non-toxic anti-metastatic agents. Dihydromotuporamine C demonstrated good anti-invasive properties with tumor cells. Derivatives were made in an effort to reduce the cytotoxicity of the parent and improve the anti-migration potency. The motuporamine derivatives all have a polyamine message (norspermidine or homospermidine) appended to make a macrocycle core, making them prime targets to evaluate as potential PTS ligands in the CHO and CHO-MG* screen. Each compound was also tested in the highly metastatic pancreatic cancer cell line L3.6pl to determine both its IC50 value and maximum tolerated dose (MTD). The anti-migration assay was performed at the lowest MTD obtained (0.6 (&)#181;M) in order to compare the series at the same non-toxic dose. The results suggested that as the N1-amine center was moved further from the macrocyclic ring, an increased ability to inhibit cell migration and reduced toxicity was observed. These collective findings provide new tools for cell biologists to modulate and target polyamine transport in mammalian cells. Future applications of these technologies include new cancer therapies which are cell-selective and inhibit the spread of tumors.
Show less - Date Issued
- 2012
- Identifier
- CFE0004636, ucf:49895
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004636
- Title
- Electronic transport and correlations in single magnetic molecule devices.
- Creator
-
Romero, Javier, Mucciolo, Eduardo, Del Barco, Enrique, Stolbov, Sergey, Hernandez, Florencio, University of Central Florida
- Abstract / Description
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In this dissertation, we study the most important microscopic aspects that grant molecules such as Single Molecule Magnets (SMMs) their preferential spin direction. We do so by proposing and solving a model that includes correlations between electrons occupying atomic orbitals. In addition, we study the relation between the non-equilibrium electronic transport signatures in a SMM model weakly coupled to a three-terminal single electron transistor device, and the interference features of the...
Show moreIn this dissertation, we study the most important microscopic aspects that grant molecules such as Single Molecule Magnets (SMMs) their preferential spin direction. We do so by proposing and solving a model that includes correlations between electrons occupying atomic orbitals. In addition, we study the relation between the non-equilibrium electronic transport signatures in a SMM model weakly coupled to a three-terminal single electron transistor device, and the interference features of the SMM model in the presence of a magnetic field. Finally, we investigate the equilibrium transport features in a giant-spin model of a SMM in the Kondo regime. We study how the magnetic field modulation of the energy in a highly anisotropic molecule can affect the conductance of the molecule in the Kondo regime.
Show less - Date Issued
- 2014
- Identifier
- CFE0005407, ucf:50420
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005407
- Title
- An assessment of ecological processes in the Apalachicola estuarine system, Florida.
- Creator
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Smar, Daina, Hagen, Scott, Wang, Dingbao, Weishampel, John, University of Central Florida
- Abstract / Description
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The following is a compilation of field data collected in 2011 and 2012 in Apalachicola, FL as part of a five year study assessing the ecological effects of sea level rise in the northern Gulf of Mexico. Many coastal communities, both natural and developed, will soon be working to mitigate the effects of sea level rise, if they are not already doing so. This thesis investigates the natural patterns of the Apalachicola estuarine system through the collection and analysis of in situ water,...
Show moreThe following is a compilation of field data collected in 2011 and 2012 in Apalachicola, FL as part of a five year study assessing the ecological effects of sea level rise in the northern Gulf of Mexico. Many coastal communities, both natural and developed, will soon be working to mitigate the effects of sea level rise, if they are not already doing so. This thesis investigates the natural patterns of the Apalachicola estuarine system through the collection and analysis of in situ water, sediment, and biomass samples. Additionally, results of the field samples are presented and recommendations for additional sampling are given. The field methods and procedures developed in this study were designed to be repeated in other estuaries to build upon the work that has been conducted in Apalachicola. Water samples were tested for total suspended solids (TSS) and compared against hydrodynamic (tidal circulation and streamflow) and meteorological (wind and precipitation) characteristics. Streamflow was determined to influence a seasonal base level concentration of TSS. Wind strength and direction consistently influenced small TSS concentration fluctuations, an effect amplified by the shallow nature of the estuary. Tidal circulation appeared to have minor influences on TSS concentration fluctuations within the base level concentration range. Precipitation appeared to influence large TSS concentration fluctuations; however, due to limited data collection during storm events, more data is required to conclusively state this. Sediment cores throughout the lower Apalachicola River revealed that coarse particles settled out in upstream areas while fine particles tended to stay in suspension until low energy areas in the lower portions of the river or marsh system were reached. Finally, biomass samples were used to develop regression models utilizing remotely sensed data to predict biomass density in marsh areas with unprecedented accuracy. The documented patterns of this system are to be used as inputs and validation points to update an existing hydrodynamic model and to aid in the coupling and development of sediment transport and marsh equilibrium models. The field campaign developed and implemented here provides a foundation for this novel coupled modeling effort of estuarine systems. From the 2011 and 2012 sampling conducted, it is apparent that Apalachicola can be modeled as a closed system with river inflow and sediment influx as boundary conditions. Forcing local conditions should accurately represent the system. Ultimately, these models will be used to simulate future sea level rise scenarios and will provide useful decision making tools to coastal managers. Future work will include replicating water sampling in subsequent wet and dry seasons in Apalachicola, FL to confirm observed trends, in addition to implementing this sampling in Grand Bay, MS and Weeks Bay, AL. Additional biomass samples will be taken to validate the strong correlations found between remotely sensed data and in situ samples. In similar studies, it is recommended that water samples be taken to adequately represent influences from tidal cycles and riverine inflow. It is also recommended that spatially distributed biomass samples be taken to validate regression models.
Show less - Date Issued
- 2012
- Identifier
- CFE0004602, ucf:49920
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004602
- Title
- Study of Transport Phenomena in Carbon-Based Materials.
- Creator
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Aboelsoud, Walid, Chow, Louis, Kumar, Ranganathan, Deng, Weiwei, Kar, Aravinda, University of Central Florida
- Abstract / Description
-
In air-cooled heat exchangers, air-side thermal resistance is usually the largest compared to conduction and liquid-side thermal resistances. Thus, reducing the air-side thermal resistance with fin-like structures can greatly improve overall cooling performance. The performance of these structures is usually characterized by the rate of heat which can be transferred and the pumping power required. One promising solution is to use a high-thermal-conductivity material with a large surface per...
Show moreIn air-cooled heat exchangers, air-side thermal resistance is usually the largest compared to conduction and liquid-side thermal resistances. Thus, reducing the air-side thermal resistance with fin-like structures can greatly improve overall cooling performance. The performance of these structures is usually characterized by the rate of heat which can be transferred and the pumping power required. One promising solution is to use a high-thermal-conductivity material with a large surface per unit volume such as carbon foam. This study presents a method of utilizing V-shape corrugated carbon foam. The air-side heat transfer coefficient and the pressure drop across the foam have been investigated using different V-shape foam geometrical configurations obtained by varying its length and height. Based on design considerations and availability, the foam length has been chosen to be 25.4, 38.1 and 52.1 mm while its height is 4.4, 6.8 and 11.7 mm, resulting in nine different test pieces of foam with different heights and lengths.A total number of 81 experiments were carried out and results show that of the nine V-shape configurations, the foam with the shortest length and tallest height gives the best performance. Experimental results are also compared with the results of prior work using different carbon foam geometries. It is shown that V-shape corrugated carbon foam provides higher heat transfer coefficient and better overall performance.Numerical method is performed next. The effect of the foam length and height on thermal and hydraulic performance is demonstrated and discussed. There is excellent agreement between numerical and experimental results. An analysis is also made to better understand the transport phenomena that occur within the porous matrix. For laminar flow of air, one of the findings is the high heat transfer effectiveness of the foam which means a foam thickness of 1 mm or less is sufficient for heat transfer enhancement for air speed of up to 4 m/s. To demonstrate the feasibility of using carbon foam, an analytical case study of carbon foam heat exchanger was performed and compared to traditional heat exchanger with the same heat load. Results show that a volume saving of up to 55% can be obtained by using carbon foam instead of traditional aluminum fins.Another attractive carbon-based material is the highly oriented pyrolytic graphite (HOPG) which has an in-plane thermal conductivity of about 1700 W/m.K and an out-of-plane k of about 8 W/m.K at room temperature. HOPG is a graphite material with a high degree of preferred crystallographic orientation. HOPG can be very useful in thermal applications when axial conduction is critical and needed to be minimized as in recuperators used in cryocoolers and compact power generation. Also, an analysis of HOPG for micro-channel applications shows that the high in-plane thermal conductivity of HOPG, which is far greater than that of copper and aluminum, allows a taller height for the micro-channel. This translates to an increase in the heat flux removal rate by two to three times.
Show less - Date Issued
- 2013
- Identifier
- CFE0005081, ucf:50732
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005081
- Title
- Sustainability Analysis of Intelligent Transportation Systems.
- Creator
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Ercan, Tolga, Tatari, Mehmet, Al-Deek, Haitham, Oloufa, Amr, University of Central Florida
- Abstract / Description
-
Commuters in urban areas suffer from traffic congestion on a daily basis. The increasing number of vehicles and vehicle miles traveled (VMT) are exacerbating this congested roadway problem for society. Although literature contains numerous studies that strive to propose solutions to this congestion problem, the problem is still prevalent today. Traffic congestion problem affects society's quality of life socially, economically, and environmentally. In order to alleviate the unsustainable...
Show moreCommuters in urban areas suffer from traffic congestion on a daily basis. The increasing number of vehicles and vehicle miles traveled (VMT) are exacerbating this congested roadway problem for society. Although literature contains numerous studies that strive to propose solutions to this congestion problem, the problem is still prevalent today. Traffic congestion problem affects society's quality of life socially, economically, and environmentally. In order to alleviate the unsustainable impacts of the congested roadway problem, Intelligent Transportation Systems (ITS) has been utilized to improve sustainable transportation systems in the world. The purpose of this thesis is to analyze the sustainable impacts and performance of the utilization of ITS in the United States. This thesis advances the body of knowledge of sustainability impacts of ITS related congestion relief through a triple bottom line (TBL) evaluation in the United States. TBL impacts analyze from a holistic perspective, rather than considering only the direct economic benefits. A critical approach to this research was to include both the direct and the indirect environmental and socio-economic impacts associated with the chain of supply paths of traffic congestion relief. To accomplish this aim, net benefits of ITS implementations are analyzed in 101 cities in the United States. In addition to the state level results, seven metropolitan cities in Florida are investigated in detail among these 101 cities. For instance, the results of this study indicated that Florida saved 1.38 E+05 tons of greenhouse gas emissions (tons of carbon dioxide equivalent), $420 million of annual delay reduction costs, and $17.2 million of net fuel-based costs. Furthermore, to quantify the relative impact and sustainability performance of different ITS technologies, several ITS solutions are analyzed in terms of total costs (initial and operation (&) maintenance costs) and benefits (value of time, emissions, and safety). To account for the uncertainty in benefit and cost analyses, a fuzzy-data envelopment analysis (DEA) methodology is utilized instead of the traditional DEA approach for sustainability performance analysis. The results using the fuzzy-DEA approach indicate that some of the ITS investments are not efficient compared to other investments where as all of them are highly effective investments in terms of the cost/benefit ratios approach. The TBL results of this study provide more comprehensive picture of socio-economic benefits which include the negative and indirect indicators and environmental benefits for ITS related congestion relief. In addition, sustainability performance comparisons and TBL analysis of ITS investments contained encouraging results to support decision makers to pursue ITS projects in the future.
Show less - Date Issued
- 2013
- Identifier
- CFE0004994, ucf:49549
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004994
- Title
- IDENTIFYING THE EFFECTS OF A HUMAN DYNEIN MUTATION ON GFP-RAB7 AXONAL TRANSPORT IN EMBRYONIC MOUSE NEURONS.
- Creator
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Wilson, Natalie E, King, Stephen, University of Central Florida
- Abstract / Description
-
The first dynein mutation found in humans that caused disease was a cytoplasmic dynein 1 heavy chain (DYNC1H1 in humans) p.His306Arg mutation, first described by Weedon et al. in 2011. This mutation caused Charcot-Marie-Tooth (CMT) subtype 2O. CMT has a prevalence of approximately 1 in 2500 people, making it the most common hereditary neuromuscular disorder. Cytoplasmic dynein 1 is used by eukaryotic cells for minus-end directed microtubule-based transport of cargo. One such cargo is Rab7, a...
Show moreThe first dynein mutation found in humans that caused disease was a cytoplasmic dynein 1 heavy chain (DYNC1H1 in humans) p.His306Arg mutation, first described by Weedon et al. in 2011. This mutation caused Charcot-Marie-Tooth (CMT) subtype 2O. CMT has a prevalence of approximately 1 in 2500 people, making it the most common hereditary neuromuscular disorder. Cytoplasmic dynein 1 is used by eukaryotic cells for minus-end directed microtubule-based transport of cargo. One such cargo is Rab7, a late endosomal marker. The purpose of this study is to identify the effects of this mutation on the transport of GFP-tagged Rab7 cargo in neurons from wild type (HH), heterozygous mutant (HR), and homozygous mutant (RR) mice harboring a DYNC1HI His306Arg mutation. Mouse embryos were euthanized, dissected to collect the hippocampal and cortical brain tissues, and these tissues were digested to isolate neurons. Nucleofection was used to introduce the exogenous GFP-Rab7 gene construct. These neurons were plated and imaged at 10 days in vitro using wide-field epifluorescence microscopy to generate image stacks of fluorescent GFP-Rab7 vesicles. Kymograph analysis was performed on the image stacks using MetaMorph software to measure several characteristics of movement. Statistical analysis of the data from each of the three genotypes shows there is no significant difference in Rab-7 transport between the three genotypes.
Show less - Date Issued
- 2017
- Identifier
- CFH2000265, ucf:45979
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000265
- Title
- REGULATION OF VLDL TRAFFICKING BY ORP 10.
- Creator
-
Wessels, Philip, Siddiqi, Shadab, University of Central Florida
- Abstract / Description
-
Of the challenges facing the improvement of human health, none has taken the forefront quite like the endeavor to discover novel treatments for heart disease. As heart disease has now become the leading cause of death throughout the world , the medical community has made incredible strides in the mission to treat atherosclerosis which is the major contributor to heart disease. Very Low Density Lipoproteins (VLDL) are secreted by the liver and subsequently converted to Low Density Lipoproteins...
Show moreOf the challenges facing the improvement of human health, none has taken the forefront quite like the endeavor to discover novel treatments for heart disease. As heart disease has now become the leading cause of death throughout the world , the medical community has made incredible strides in the mission to treat atherosclerosis which is the major contributor to heart disease. Very Low Density Lipoproteins (VLDL) are secreted by the liver and subsequently converted to Low Density Lipoproteins (LDL). Many factors contribute to the narrowing of the arterial walls, however oxidized LDL is the main factor that leads to the deposition of plaque, leading to atherosclerosis pathologies. Recently, a main focus of research into atherosclerotic processes has been the synthesis and trafficking of VLDL in hepatocytes. The rate-limiting step for the secretion of VLDL from the liver has been determined to be the transport of VLDL from the endoplasmic reticulum (ER) to the Golgi apparatus. VLDL molecules are transported in a specialized transport vesicle the Very Low Density Lipoprotein Transport Vesicle (VTV) . VLDL's core protein, apolipoproteinB-100 (apoB100), is initially lipidated in the ER, and then subsequently delivered to the Golgi apparatus where the VLDL molecule undergoes maturation involving further lipidation and glycosylation of apoB100. Oxysterol Binding Proteins (OSBP) and the sub family OSBP Related Proteins (ORP) have been implicated in many different trafficking processes, mainly the trafficking of sterols, cholesterol, and lipids. Recently, ORP 10 was shown to be a negative regulator of apoB100 secretion in growth medium . Using co-immunoprecipitation, the current study shows that ORP 10 interacts with VLDL's core protein apoB100 directly. Employing an in vitro budding assay, we show that the blocking of ORP 10 with a specific antibody against ORP10 increases VTV formation from the ER. Given that the ER to Golgi pathway is the rate-limiting step in overall VLDL secretion, these findings support the conclusion that ORP 10 is a negative regulator of VLDL trafficking between the ER and Golgi, and that this process is mediated by the ORP 10 protein binding with apoB100.
Show less - Date Issued
- 2015
- Identifier
- CFH0004866, ucf:45491
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004866
- Title
- FABRICATION AND TRANSPORT STUDIES OF N-TYPE ORGANIC FIELD EFFECT TRANSISTORS USING ALIGNED ARRAY CARBON NANOTUBES ELECTRODES.
- Creator
-
Jimenez, Edwards, Khondaker, Saiful, University of Central Florida
- Abstract / Description
-
We present fabrication of n-type organic field effect transistors (OFETs) using densely aligned array carbon nanotube (CNT) electrodes. The CNTs were aligned with a high linear density via dielectrophoresis (DEP) from an aqueous solution. In order to fabricate the CNT electrodes, aligned CNTs were cut by using electron beam lithography (EBL) and precise oxygen plasma etching. The n-type OFETs were fabricated in a bottom-contact configuration by depositing a thin film of C60 molecules between...
Show moreWe present fabrication of n-type organic field effect transistors (OFETs) using densely aligned array carbon nanotube (CNT) electrodes. The CNTs were aligned with a high linear density via dielectrophoresis (DEP) from an aqueous solution. In order to fabricate the CNT electrodes, aligned CNTs were cut by using electron beam lithography (EBL) and precise oxygen plasma etching. The n-type OFETs were fabricated in a bottom-contact configuration by depositing a thin film of C60 molecules between the CNT source and drain electrodes, and compared against a controlled C60 OFET with gold electrodes. The electron transport measurements of the OFETs using CNT electrodes show better transistor characteristics compared to OFETs using gold electrodes due to improved charge injection from densely aligned and open-ended nanotube tips.
Show less - Date Issued
- 2012
- Identifier
- CFH0004217, ucf:44941
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004217
- Title
- AN INTEGRATED HYDROLOGY/HYDRAULIC AND WATER QUALITY MODEL FOR WATERSHED-SCALE SIMULATIONS.
- Creator
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Wang, Cheng, Yeh, Gour-Tsyh, University of Central Florida
- Abstract / Description
-
This dissertation presents the design of an integrated watershed model, WASH123D version 3.0, a first principle, physics-based watershed-scale model of integrated hydrology/hydraulics and water quality transport. This numerical model is comprised of three modules: (1) a one-dimensional (1-D) simulation module that is capable of simulating separated and coupled fluid flow, sediment transport and reaction-based water quality transport in river/stream/canal networks and through control...
Show moreThis dissertation presents the design of an integrated watershed model, WASH123D version 3.0, a first principle, physics-based watershed-scale model of integrated hydrology/hydraulics and water quality transport. This numerical model is comprised of three modules: (1) a one-dimensional (1-D) simulation module that is capable of simulating separated and coupled fluid flow, sediment transport and reaction-based water quality transport in river/stream/canal networks and through control structures; (2) a two-dimensional (2-D) simulation module, capable of simulating separated and coupled fluid flow, sediment transport, and reactive biogeochemical transport and transformation in two-dimensional overland flow systems; and (3) a three-dimensional (3-D) simulation module, capable of simulating separated and coupled fluid flow and reactive geochemical transport and transformation in three-dimensional variably saturated subsurface systems. The Saint Venant equation and its simplified versions, diffusion wave and kinematic wave forms, are employed for surface fluid flow simulations and the modified Richards equation is applied for subsurface flow simulation. The reaction-based advection-dispersion equation is used as the governing equation for water quality transport. Several physically and mathematically based numerical options are provided to solve these governing equations for different application purposes. The surface-subsurface water interactions are considered in the flow module and simulated on the basis of continuity of interface. In the transport simulations, fast/equilibrium reactions are decoupled from slow/kinetic reactions by the decomposition of reaction networks; this enables robust numerical integrations of the governing equation. Kinetic variables are adopted as primary dependent variables rather than biogeochemical species to reduce the number of transport equations and simplify the reaction terms. In each time step, hydrologic/hydraulic variables are solved in the flow module; kinetic variables are then solved in the transport module. This is followed by solving the reactive chemical system node by node to yield concentrations of all species. Application examples are presented to demonstrate the design capability of the model. This model may be of interest to environmental scientists, engineers and decision makers as a comprehensive assessment tool to reliably predict the fluid flow as well as sediment and contaminant transport on watershed scales so as to evaluate the efficacy and impact of alternative watershed management and remediation techniques prior to incurring expense in the field.
Show less - Date Issued
- 2009
- Identifier
- CFE0002947, ucf:47955
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002947
- Title
- Narrative Transportation and Virtual Reality: Exploring the Immersive Qualities of Social Justice in the Digital World.
- Creator
-
Raffel, Sara, McDaniel, Rudy, Jones, Natasha, Salter, Anastasia, Rettberg, Jill, University of Central Florida
- Abstract / Description
-
This dissertation explores the potential applications for virtual reality (VR) stories in support of social justice causes, examining whether digital games historically been successfully leveraged for social justice purposes, and determining which components of VR technology can most encourage narrative transportation of participants in VR stories.The first chapter examines theories of simulation, virtual reality, narrative, and interactivity, as well as concepts of immersion from various...
Show moreThis dissertation explores the potential applications for virtual reality (VR) stories in support of social justice causes, examining whether digital games historically been successfully leveraged for social justice purposes, and determining which components of VR technology can most encourage narrative transportation of participants in VR stories.The first chapter examines theories of simulation, virtual reality, narrative, and interactivity, as well as concepts of immersion from various disciplines and settles on narrative transportation, a theory from cognitive psychology, as the most useful in measuring the effect of VR stories on participants.The second chapter examines ethnographic practices, activist games, and modes of reclaiming digital spaces as a way to encourage digital social justice and ensure traditionally marginalized communities have meaningful access to technology(-)or, the tools to use it, create with it, and critique it.The third chapter presents the result of a play study conducted to measure participants' transportation in a recent VR narrative and finds VR interactive narratives to be more transportive and engaging than their two-dimensional counterparts.The fourth chapter interrogates some of the fears of VR technology, namely that it will be used to further current societal injustices and as a potentially powerful propaganda tool.The final chapter presents five recommendations for designers seeking to experiment in virtual reality narratives. The ultimate aim of this work is to encourage scholars, designers, and participants to make ethical decisions in the creation and use of virtual societies.
Show less - Date Issued
- 2018
- Identifier
- CFE0007080, ucf:52015
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007080
