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- Title
- OSCILLATORY FLOW AS A MEANS OF ENHANCED SPECIES SEPARATION: A THREE DIMENSIONAL TIME-ACCURATE CFD ANALYSIS.
- Creator
-
Crain, Jennifer, Divo, Eduardo, University of Central Florida
- Abstract / Description
-
A fluid that contains species in the presence of a concentration gradient generates unusual phenomena when it is forced into pulsatile motion. For example, each species in the fluid has an enhanced mass transport due to pure molecular diffusion. This enhancement takes place even if there is no net total flow over a cycle of the pulsatile motion. When more than one species in dilute amounts is present in an otherwise pure fluid, called a carrier, each species is transported at a different rate...
Show moreA fluid that contains species in the presence of a concentration gradient generates unusual phenomena when it is forced into pulsatile motion. For example, each species in the fluid has an enhanced mass transport due to pure molecular diffusion. This enhancement takes place even if there is no net total flow over a cycle of the pulsatile motion. When more than one species in dilute amounts is present in an otherwise pure fluid, called a carrier, each species is transported at a different rate thereby causing a partial separation of the species. This idea traces back to hyperventilation studies done over 40 years ago and to the implementation of the technology in hospital environments to provide life-support for patients under anesthesia. However, it is only in recent years that the underlying physics of oscillatory flow as applied to mass transfer have been understood and this may lead to promising application of the technique to novel means of enhancing separation in life support applications and for detection purposes. In this thesis, results from three-dimensional time accurate studies carried out using the commercial computational fluid dynamics code FLUENT are presented. These results simulate the separation of CO2 from He in an N2 environment (carrier). The model consists of two reservoirs/mixing chambers, an oscillating piston wall, and a connecting tube. Several cases are carried out reporting on separation enhancement as a function of the Womersley number and the ratio of tidal displacement to connecting tube diameter. Unlike previous studies which were undertaken using asymptotic analysis, the present models and results incorporate full entrance effects and 3D interactions. Results of this study will be useful as a guide for the design and miniaturization of an oscillating device for species separation in further research projects at the University of Central Florida. Observations showed that a molar fraction increase occurs during the species transport in the presence of a thermal boundary layer. This was accompanied by an imposed external forced temperature condition on the surface of the cylinder to create thermal diffusion, also known as the Soret or thermal diffusion effect, which refers to the separation of mixtures in a temperature gradient as means of change on the concentration gradient of the species ratio. Calculations were performed to analyze the effect of the heat transfer on the molar fraction of the species at a specific region of the model, called the measurement point. Various mathematical models and correlations were incorporated into a MATLAB computer code that predicted the concentration of the species in an entire cycle after steady state is reached and data can be exported from FLUENT.
Show less - Date Issued
- 2006
- Identifier
- CFE0001095, ucf:46783
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001095
- Title
- A COMPARATIVE STATIC ANALYSIS FOR INVASIVE SPECIES MANAGEMENT UNDER RISK NEUTRAL PREFERENCES.
- Creator
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Safford, Pamela, Finnoff, David, University of Central Florida
- Abstract / Description
-
This thesis investigates the optimal ex-ante mix of self-protection and self-insurance technologies employed to reduce the risk of biological invaders in the presence of exogenous variables within the probability and damage functions. This is accomplished by using a theoretical endogenous risk model that extends previously developed frameworks. This thesis contributes to the previous work in two ways. (1) employing a general framework with simultaneous decision making over self-protection and...
Show moreThis thesis investigates the optimal ex-ante mix of self-protection and self-insurance technologies employed to reduce the risk of biological invaders in the presence of exogenous variables within the probability and damage functions. This is accomplished by using a theoretical endogenous risk model that extends previously developed frameworks. This thesis contributes to the previous work in two ways. (1) employing a general framework with simultaneous decision making over self-protection and self-insurance, this thesis analyzes how each parameter including income, the costs of each activity, an exogenous factor that affects only the probability of an invasion, and a separate exogenous factor that affects only the damages influence the level of self-protection and self-insurance. (2) the comparative static results are derived in the benchmark case of risk neutral preferences and qualitatively compared to an extended case of risk averse preferences. The results of the analysis indicate that under risk neutral preferences the signs of the comparative statics are unambiguous while under risk aversion the results are not clearly defined. Thus, the ambiguity of signs in the latter case can be attributed to the unobservable utility terms present under risk averse preferences. Therefore, it can be concluded that the model is not capable of yielding a decision criteria that will hold universally because the results are dependent on the nature of the risk averse curve
Show less - Date Issued
- 2004
- Identifier
- CFE0000156, ucf:46172
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000156
- Title
- The effects of non-native species on two life-stages of the Eastern oyster (<)i(>)Crassostrea virginica(<)/i(>).
- Creator
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Yuan, Wei, Walters, Linda, Hoffman, Eric, Fauth, John, Scarpa, John, University of Central Florida
- Abstract / Description
-
Since their recent introductions into Florida waters, three nonnative species [()Perna viridis() Linnaeus, 1758 (Asian green mussel), ()Mytella charruana() d'Orbigny, 1846 (charru mussel) and ()Megabalanus coccopoma() Darwin, 1854 (pink titan acorn barnacle)] have expanded both north and south along the Atlantic coast. Very little research has been done to understand how these nonnative species interact with the native eastern oyster (()Crassostrea virginica() Gmelin, 1791), which is a...
Show moreSince their recent introductions into Florida waters, three nonnative species [(<)i(>)Perna viridis(<)/i(>) Linnaeus, 1758 (Asian green mussel), (<)i(>)Mytella charruana(<)/i(>) d'Orbigny, 1846 (charru mussel) and (<)i(>)Megabalanus coccopoma(<)/i(>) Darwin, 1854 (pink titan acorn barnacle)] have expanded both north and south along the Atlantic coast. Very little research has been done to understand how these nonnative species interact with the native eastern oyster ((<)i(>)Crassostrea virginica(<)/i(>) Gmelin, 1791), which is a keystone species that provides important ecological services and economic benefits. To test the potential effects of (<)i(>)P. viridis, M. charruana(<)/i(>) and (<)i(>)M. coccopoma(<)/i(>) on (<)i(>)C. virginica(<)/i(>), I addressed the following questions: 1a) Does the presence of nonnative species decrease oyster larval settlement? 1b) Do oyster larvae avoid settling on oyster shells to which nonnative species are attached? 2a) Do nonnative species decrease survival of juvenile oysters (spat)? and 2b) Do nonnative species hinder spat growth? My manipulative experiments showed that the tested nonnative species influenced settlement, growth and survival of (<)i(>)C. virginica(<)/i(>) in unique ways. (<)i(>)Megabalanus coccopoma(<)/i(>) decreased the total number of settled oyster larvae, but did not influence larval preference or survival and growth of spat. (<)i(>)Perna viridis(<)/i(>) negatively influenced larval settlement and oyster larvae avoided settling on shells of (<)i(>)P. viridis(<)/i(>). (<)i(>)Mytella charruana(<)/i(>) had no influence on the total number of settled larvae but oyster larvae avoided settling on oyster shell with (<)i(>)M. charruana(<)/i(>) or on the mussel shells themselves. Furthermore, both nonnative mussels negatively affected the survival of juvenile oysters, but only (<)i(>)M. charruana(<)/i(>) reduced spat growth. These three nonnative species should be classified as invasive species because all had negative effects on the native oyster (<)i(>)C. virginica(<)/i(>).
Show less - Date Issued
- 2014
- Identifier
- CFE0005448, ucf:50377
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005448
- Title
- IS THE EXOTIC BRAZILIAN PEPPER, SCHINUS TEREBINTHIFOLIUS, A THREAT TO MANGROVE ECOSYSTEMS IN FLORIDA?.
- Creator
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Donnelly, Melinda, Walters, Linda, University of Central Florida
- Abstract / Description
-
Mangrove ecosystems are critical to Florida, providing economic resources to humans, and untold ecological resources to estuarine organisms. In Florida's estuaries, mangrove ecosystems have suffered significant losses due to natural and human disturbances; these disturbances potentially leave mangrove communities vulnerable to invasion by the opportunistic exotic, Schinus terebinthifolius (Brazilian pepper). Prior experiments have suggested that Schinus terebinthifolius is unable to survive...
Show moreMangrove ecosystems are critical to Florida, providing economic resources to humans, and untold ecological resources to estuarine organisms. In Florida's estuaries, mangrove ecosystems have suffered significant losses due to natural and human disturbances; these disturbances potentially leave mangrove communities vulnerable to invasion by the opportunistic exotic, Schinus terebinthifolius (Brazilian pepper). Prior experiments have suggested that Schinus terebinthifolius is unable to survive under marine conditions and poses no long term threat to mangrove systems. However, this contradicts field observations where Schinus terebinthifolius was found growing in the intertidal zone of Mosquito Lagoon alongside three native species of mangroves, Rhizophora mangle, Avicennia germinans and Laguncularia racemosa. The purpose of my study was to evaluate competition between the invasive S. terebinthifolius and these three native species of mangroves in the coastal estuarine system along the east coast of Central Florida in Canaveral National Seashore. The effects of competition were evaluated by testing the ability of S. terebinthifolius to: 1) chemically inhibit growth of mangrove propagules, 2) invade new coastal habitats by dispersing seeds in the water, 3) alter species richness and abundance of the flora when present in a mangrove system, and 4) recruit and survive in mangrove habitat. By better understanding the invasibility and impact of Schinus terebinthifolius on mangroves, coastal resource managers will be able to develop the most effective management strategies to prevent this exotic from altering the structure and productivity of the mangrove ecosystem.
Show less - Date Issued
- 2006
- Identifier
- CFE0000998, ucf:46713
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000998
- Title
- PREDICTING RISKS OF INVASION OF CAULERPA SPECIES IN FLORIDA.
- Creator
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Glardon, Christian, Walters, Linda, University of Central Florida
- Abstract / Description
-
Invasions of exotic species are one of the primary causes of biodiversity loss on our planet (National Research Council 1995). In the marine environment, all habitat types including estuaries, coral reefs, mud flats, and rocky intertidal shorelines have been impacted (e.g. Bertness et al. 2001). Recently, the topic of invasive species has caught the public's attention. In particular, there is worldwide concern about the aquarium strain of the green alga Caulerpa taxifolia (Vahl) C. Agardh...
Show moreInvasions of exotic species are one of the primary causes of biodiversity loss on our planet (National Research Council 1995). In the marine environment, all habitat types including estuaries, coral reefs, mud flats, and rocky intertidal shorelines have been impacted (e.g. Bertness et al. 2001). Recently, the topic of invasive species has caught the public's attention. In particular, there is worldwide concern about the aquarium strain of the green alga Caulerpa taxifolia (Vahl) C. Agardh that was introduced to the Mediterranean Sea in 1984 from the Monaco Oceanographic Museum. Since that time, it has flourished in thousands of hectares of near-shore waters. More recently, C. taxifolia has invaded southern Californian and Australian waters. Since the waters of Florida are similar to the waters of the Mediterranean Sea and other invasive sites my study will focus on determining potential invasion locations in Florida. I will look at the present distribution of C. taxifolia - native strain in Florida as well as the distribution of the whole genus around the state. During this study, I address three questions: 1) What is the current distribution of Caulerpa spp. in Florida? 2) Can I predict the location of potential Caulerpa spp. invasions using a set of environmental parameters and correlate them to the occurrence of the algae with the support of Geographic Information System (GIS) maps? 3) Using the results of part two, is there an ecological preferred environment for one or all Caulerpa spp. in Florida? To answer these questions, I surveyed 24 areas in each of 6 zones chosen in a stratified manner along the Floridian coastline to evaluate the association of potential indicators Caulerpa. Latitude, presence or absence of seagrass beds, human population density, and proximity to marinas were chosen as the 4 parameters expected to correlate to Caulerpa occurrences. A logistic regression model assessing the association of Caulerpa occurrence with measured variables has been developed to predict current and future probabilities of Caulerpa spp. presence throughout the state. Fourteen different species of Caulerpa spp. were found in 26 of the 132 sites visited. There was a positive correlation between Caulerpa spp. and seagrass beds presence and proximity to marinas. There was a negative correlation with latitude and human population density. C. taxifolia – aquarium strain wasn't found. Percent correct for our model was of 61.5% for presence and 98.1% for absence. This prediction model will allow us to focus on particular areas for future surveys.
Show less - Date Issued
- 2006
- Identifier
- CFE0001041, ucf:46796
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001041
- Title
- LIMNOLOGICAL AND LANDSCAPE FACTORS AFFECTING USE OF MANUFACTURED PONDS BY THE INVASIVE CUBAN TREEFROG (OSTEOPILUS SEPTENTRIONALIS).
- Creator
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Nusinov, Terina, Fauth, John, University of Central Florida
- Abstract / Description
-
Exotic amphibians are often detrimental to native biotas. In Florida, the exotic Cuban Treefrog (Osteopilus septentrionalis) eats native frogs and may outcompete them for resources. Cuban Treefrogs thrive in disturbed areas and around buildings, and often breed in manufactured wetlands such as retention ponds and borrow pits. This study identified limnological, landscape, and biotic characteristics that discouraged pond use by Cuban Treefrogs and promoted use by native amphibian species. I...
Show moreExotic amphibians are often detrimental to native biotas. In Florida, the exotic Cuban Treefrog (Osteopilus septentrionalis) eats native frogs and may outcompete them for resources. Cuban Treefrogs thrive in disturbed areas and around buildings, and often breed in manufactured wetlands such as retention ponds and borrow pits. This study identified limnological, landscape, and biotic characteristics that discouraged pond use by Cuban Treefrogs and promoted use by native amphibian species. I sampled natural and manufactured ponds in Orange County, Florida, for one year, using standard methods to estimate the species richness and relative abundance of amphibians and their potential fish and macroinvertebrate predators. I determined the relationship between the presence of Cuban Treefrogs and twelve limnological (% vegetation, slope, pond age, pH, % dissolved oxygen, air temperature, water temperature, turbidity, conductivity, depth, perimeter, and area) and seven landscape characteristics (% canopy closure over ponds, building density, distance to nearest building, road density, distance to nearest road, distance to nearest forest stand, and % forest cover), plus five biotic factors (native amphibian richness and abundance, fish richness and abundance, and macroinvertebrate abundance). No relationship existed between native amphibian abundance or species richness and the presence or absence of Cuban Treefrogs. Ponds with a greater percentage of vegetation, large perimeters, and low pH and turbidity had greater native amphibian species richness. Cuban Treefrogs were more likely to be found in ponds with a greater percentage of aquatic vegetation and small perimeters. My results show that building large retention ponds containing low-turbidity water will restrict colonization by Cuban Treefrogs and maintain species richness of native amphibians.
Show less - Date Issued
- 2006
- Identifier
- CFE0001000, ucf:46837
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001000
- Title
- Species and habitat interactions of the gopher tortoise: A keystone species?.
- Creator
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Catano, Christopher, Hinkle, Charles, Stout, I, Jenkins, David, University of Central Florida
- Abstract / Description
-
Species-species and species-habitat interactions have been demonstrated to be important in influencing diversity across a variety of ecosystems. Despite generalities in the importance of these interactions, appropriate mechanisms to explain them are absent in many systems. In sandhill systems of the southeast U.S., gopher tortoises have been hypothesized to be a crucial species in the maintenance of diversity and function. However, the mechanisms and magnitude in which they influence their...
Show moreSpecies-species and species-habitat interactions have been demonstrated to be important in influencing diversity across a variety of ecosystems. Despite generalities in the importance of these interactions, appropriate mechanisms to explain them are absent in many systems. In sandhill systems of the southeast U.S., gopher tortoises have been hypothesized to be a crucial species in the maintenance of diversity and function. However, the mechanisms and magnitude in which they influence their communities and habitats have rarely been empirically quantified. I examined how habitat structure influences tortoise abandonment of burrows and how tortoise densities influence non-volant vertebrate community diversity. Tortoise burrow abandonment is directly influenced by canopy closure, with each percent increase in canopy cover relating to a ~2% increase in the probability of burrow abandonment. In addition, tortoise burrow density was positively correlated with diversity and evenness, but not species richness. This influence was directly proportional to burrow density, supporting a dominance role for this species and rejecting the commonly asserted keystone species mechanism. I also quantified the influence of tortoises in influencing diversity relative to other environmental and habitat variables. Through this research, I have demonstrated that disturbance and habitat structure are important, but diversity responds most to density of burrows in the habitat. These findings demonstrate the intricate relationships interacting to maintaining diversity in sandhill systems. In particular, habitat change leading to declines of gopher tortoises may have drastic negative impacts on vertebrate species diversity.
Show less - Date Issued
- 2012
- Identifier
- CFE0004526, ucf:49246
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004526
- Title
- BIOLOGY, ECOLOGY AND CONTROL OF THE INVASIVE CHANNELED APPLE SNAIL, POMACEA CANALICULATA.
- Creator
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Trexler, Christina, Fauth, John, University of Central Florida
- Abstract / Description
-
Invasive species are detrimental to native biotas worldwide. Recently, Florida was invaded by a freshwater snail (Pomacea canaliculata) native to Argentina. This snail is a serious pest of rice crops in Asia, but little is known about its interactions within Florida ecosystems. Possible competitive exclusion of the native congener (P. paludosa) is a concern because it is the almost exclusive prey of the federally endangered Everglades snail kite (Rostrhamus sociabilis). My research consisted...
Show moreInvasive species are detrimental to native biotas worldwide. Recently, Florida was invaded by a freshwater snail (Pomacea canaliculata) native to Argentina. This snail is a serious pest of rice crops in Asia, but little is known about its interactions within Florida ecosystems. Possible competitive exclusion of the native congener (P. paludosa) is a concern because it is the almost exclusive prey of the federally endangered Everglades snail kite (Rostrhamus sociabilis). My research consisted of three parts. First, to identify possible methods to control P. canaliculata in the egg stage, I experimentally evaluated the effects of photoperiod, substrate availability, and food type and availability on hatching success and hatchling survival. None of these factors significantly affected hatching or survival, suggesting that P. canaliculata could invade many water bodies. Second, I used a randomized block design to assess the separate and combined effects of population density and food availability on growth and spawning of P. canaliculata. Food availability but not density significantly affected growth; snails fed less food grew less, but neither factor affected spawning. Third, I used a replacement series design to assess competition between P. canaliculata and P. paludosa under food limitation. For both species, snails fed less grew significantly less, and snails exposed to greater congener densities spawned less than when exposed to conspecifics only. While my results predict that P. paludosa should exclude P. canaliculata, previous literature and current invasions suggest that the exotic snail may co-exist with its North American congener.
Show less - Date Issued
- 2011
- Identifier
- CFE0003877, ucf:48725
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003877
- Title
- From pet to pest? The potential global range and food web effects of a generalist carnivore.
- Creator
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Bevan, Hannah, Jenkins, David, Noss, Reed, Campbell, Todd, University of Central Florida
- Abstract / Description
-
The Nile monitor lizard [Varanus niloticus (Linnaeus, 1766)] is a generalist carnivore, native to Sub-Saharan Africa and the Nile River but now established in North America as a result of the pet trade. Once introduced, they are a potential invasive threat to native wildlife. Here, I create ensemble species distribution models (SDMs) to predict the global distribution of this generalist carnivore given current and future climate conditions. I then quantify the monitor's potential effects on...
Show moreThe Nile monitor lizard [Varanus niloticus (Linnaeus, 1766)] is a generalist carnivore, native to Sub-Saharan Africa and the Nile River but now established in North America as a result of the pet trade. Once introduced, they are a potential invasive threat to native wildlife. Here, I create ensemble species distribution models (SDMs) to predict the global distribution of this generalist carnivore given current and future climate conditions. I then quantify the monitor's potential effects on 85 food webs representing (>)900 different species within the projected regions based on stomach content data. Climate, vegetation, and elevation data are used for 507 georeferenced observation points from the Nile monitor's native range to produce current and future (2070) ensemble SDMs. Explanatory variables are evaluated as ten alternative models organized in three subsets according to model assumptions. The true skill statistic (TSS), sensitivity, and specificity were used to assess model performance, and the best subset was averaged to represent an ensemble model. Food web impacts after the generalist predator's addition are determined by changes in nine metrics of food web structure. The most predictive (TSS scores ?0.87) ensemble SDM was based on the MARS and FDA algorithms using elevation and climate for current and future conditions. This model shows that, if introduced, Nile monitors will likely spread into many regions in the Americas, the Caribbean, Madagascar, Southeast Asia, and Australia. Assuming unabated carbon emissions by 2070, climate change will enhance that potential range. Adding Nile monitors to food webs generally increases overall trophic links, connectance, link density, and fraction of intermediate taxa, with decreases in the fraction of top and basal taxa. These results are consistent with a generalist predator that affects many species and is likely to affect food web stability. The potential Nile monitor range is vast and encompasses multiple biodiversity hotspots. Given many strong food web interactions by this generalist predator, vulnerable regions should actively prohibit/regulate Nile monitors as pets, enforce those restrictions, and promote exotic pet amnesty programs. Southern US states should especially act soon to prevent spread of the Nile monitor to the Neotropics from its current introduced population in Florida and as released pets.
Show less - Date Issued
- 2016
- Identifier
- CFE0006441, ucf:51446
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006441
- Title
- A MARXIAN CONCEPT OF HUMAN NATURE IN DEFENSE OF ALIENATION: A REVOLUTIONARY EXEGESIS OF A REVOLUTIONARY PHILOSOPHY.
- Creator
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Byron, Christopher, Jones, Donald, University of Central Florida
- Abstract / Description
-
Two long-standing and erroneous claims have plagued Marxism for the past century. First, Marx held no static view of human-nature. Second, Marx's theory of alienation was the naïve view of a young Marx, which was jettisoned in his wiser adult years. Both views are demonstrable false. Moreover, the validity of his theory of human nature, and alienation, are contingent upon the acceptance of each other. One cannot fully comprehend his view of alienation without understanding his view of human...
Show moreTwo long-standing and erroneous claims have plagued Marxism for the past century. First, Marx held no static view of human-nature. Second, Marx's theory of alienation was the naïve view of a young Marx, which was jettisoned in his wiser adult years. Both views are demonstrable false. Moreover, the validity of his theory of human nature, and alienation, are contingent upon the acceptance of each other. One cannot fully comprehend his view of alienation without understanding his view of human nature, and vice versa. Upon demonstrating Marx's theory of human nature, and defending it as a crucial bedrock for the theory of alienation, mainstream rejections of each will be considered, and critiqued. The constant misunderstanding of Marx's theory of human nature comes in his unique theory of essence. He is an essentialist, with a fluid conception of man's essence. One's historical essence is an ensemble of socio-historical reflections, dialectically interplaying off a historically transcending essentialism.
Show less - Date Issued
- 2012
- Identifier
- CFH0004149, ucf:44831
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004149
- Title
- Factors limiting native species establishment on former agricultural lands.
- Creator
-
Weiler-Lazarz, Annalisa, VonHolle, Mary, Quintana-Ascencio, Pedro, Neill, Christopher, Nickerson, David, University of Central Florida
- Abstract / Description
-
Restoration of abandoned, nonnative species-dominated agricultural lands provides opportunities for conserving declining shrubland and grassland ecosystems. Land-use legacies, such as elevated soil fertility and pH from agricultural amendments, often persist for years and can favor nonnative species at the expense of native species. Understanding the factors that limit native species establishment on abandoned agricultural lands can provide important insights for restoration and conservation...
Show moreRestoration of abandoned, nonnative species-dominated agricultural lands provides opportunities for conserving declining shrubland and grassland ecosystems. Land-use legacies, such as elevated soil fertility and pH from agricultural amendments, often persist for years and can favor nonnative species at the expense of native species. Understanding the factors that limit native species establishment on abandoned agricultural lands can provide important insights for restoration and conservation of native species on human-modified lands. I conducted two field experiments on abandoned agricultural lands: a former pasture on Martha's Vineyard, MA and a former citrus grove at Merritt Island National Wildlife Refuge (MINWR) in Titusville, FL. In these experiments I tested how soil chemical properties affect native and nonnative species abundance and how different methods of removing nonnative, invasive species affect native and nonnative species abundance. In the first experiment, specifically I tested how restoration treatments affect competition between existing nonnative agricultural plant species and native plant species that are targets for sandplain grassland restoration on Martha's Vineyard, MA. At MINWR, I examined how lowering soil fertility with carbon additions and lowering soil pH by applying sulfur affects nonnative species richness and cover (in two former citrus groves that were historically scrub/scrubby flatwoods. Overall, I found that biotic factors, such as competition with nonnative species, play a stronger role in limiting native species establishment than soil chemical properties. Likewise, control of nonnative, invasive species is most effective with mechanical treatments to physically reduce cover, rather than altering soil chemical properties.
Show less - Date Issued
- 2012
- Identifier
- CFE0004323, ucf:49462
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004323
- Title
- WATER VAPOR AND CARBON DIOXIDE SPECIES MEASUREMENT IN NARROW CHANNELS.
- Creator
-
Lambe, Derek, Basu, Saptarshi, University of Central Florida
- Abstract / Description
-
A novel method has been implemented for measuring the concentration of gas species, water vapor and carbon dioxide, within a narrow channel flow field non-invasively using tunable diode laser absorption spectroscopy (TDLAS) in conjunction with a laser modulated at a high frequency [Wavelength Modulation Spectroscopy (WMS)] tuned to the ro-vibrational transition of the species. This technique measures the absorption profile which is a strong function of the species concentration across short...
Show moreA novel method has been implemented for measuring the concentration of gas species, water vapor and carbon dioxide, within a narrow channel flow field non-invasively using tunable diode laser absorption spectroscopy (TDLAS) in conjunction with a laser modulated at a high frequency [Wavelength Modulation Spectroscopy (WMS)] tuned to the ro-vibrational transition of the species. This technique measures the absorption profile which is a strong function of the species concentration across short path lengths and small time spans, as in PEM fuel cells during high load cycles. This method has been verified in a transparent circular flow 12 cm path length and a 12 mm rectangular flow channel. Distinct absorption peaks for water vapor and carbon dioxide have been identified, and concentrations of water vapor and carbon dioxide within the test cells have been measured in situ with high temporal resolutions. A comparison of the full width at half maximum (FWHM) of the absorption lineshapes to the partial pressure of water vapor and carbon dioxide showed a predominantly linear relationship, except in the lower partial pressure regions. Test section temperature was observed to have very minimal impact on these curves at low partial pressure values. A porous media like a membrane electrode assembly (MEA) similar to those used in PEM fuel cells sandwiched between two rectangular flow channels was also tested. Some of the scattered radiation off the MEA was observed using a photodiode at high gain, allowing for more localized species detection. The technique was used to monitor the humidity on either side of the MEA during both temperature controlled and super-saturated conditions. The measurements were observed to be repeatable to within 10 %.
Show less - Date Issued
- 2009
- Identifier
- CFE0002805, ucf:48096
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002805
- Title
- Fabrication and Investigation of an enzyme-free, Nanoparticle-based Biosensor for Hydrogen Peroxide determination.
- Creator
-
Neal, Craig, Seal, Sudipta, Cho, Hyoung Jin, Florczyk, Stephen, University of Central Florida
- Abstract / Description
-
Electrochemical biosensors often employ enzymes as detection elements. These sensors are highly selective towards target analytes, however the scope of their application is limited by the poor stability of the enzyme. In this study, multi-valent inorganic cerium oxide nanoparticles were used as detection elements for the analysis of hydrogen peroxide. The electrochemical response of the cerium oxide towards hydrogen peroxide analyte is defined through cyclic voltammetry and chronoamperometry....
Show moreElectrochemical biosensors often employ enzymes as detection elements. These sensors are highly selective towards target analytes, however the scope of their application is limited by the poor stability of the enzyme. In this study, multi-valent inorganic cerium oxide nanoparticles were used as detection elements for the analysis of hydrogen peroxide. The electrochemical response of the cerium oxide towards hydrogen peroxide analyte is defined through cyclic voltammetry and chronoamperometry. This response was found to be dependent on nanoparticle Ce3+:Ce4+ redox state ratio and this property is exploited to fabricate a biosensor. As produced, the biosensor demonstrated sensitivity at picomolar analyte concentrations. Further, the sensitivity of the electrode is stable across a range of temperatures and pH's which inhibit the function of standard enzyme-based sensors. Additionally, the produced sensor retained function in sheep serum demonstrating the high selectivity and robustness of the sensor.
Show less - Date Issued
- 2016
- Identifier
- CFE0006362, ucf:51540
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006362
- Title
- SPATIOTEMPORAL VARIATION OF AVIAN POPULATIONS WITHIN GEOGRAPHICALLY ISOLATED FRESHWATER MARSHES.
- Creator
-
Rodenbeck, Brian, Weishampel, John, University of Central Florida
- Abstract / Description
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Metacommunity connectivity, i.e., multi-species dispersal events, is vital to metapopulation persistence in patchy landscapes. Assessments of metacommunity connectivity are not trivial. However, a relationship between trophic rank and the species-area relationship has been found in previous studies, allowing for the use of the predator species-area relationship to act as a surrogate measure of actual metacommunity connectivity of prey species in some systems. For this study, avian species...
Show moreMetacommunity connectivity, i.e., multi-species dispersal events, is vital to metapopulation persistence in patchy landscapes. Assessments of metacommunity connectivity are not trivial. However, a relationship between trophic rank and the species-area relationship has been found in previous studies, allowing for the use of the predator species-area relationship to act as a surrogate measure of actual metacommunity connectivity of prey species in some systems. For this study, avian species were selected as they are generalist top predators within the study system. Predator species richness within geographically isolated freshwater marshes is influenced by a number of factors. I explore the relative roles of patch area, seasonality, hydroperiod, isolation, and vegetation structure on habitat use in the isolated freshwater marshes embedded within the dry prairie ecosystem of Central Florida. Predator species richness was surveyed in 50 sites for three seasons: fall 2005, winter 2005/06, and spring 2006 and the observed avian assemblage measures were subdivided into foraging guilds for analysis. Wading guild (e.g., egrets, herons, bitterns) species richness was correlated with hydroperiod and vegetation structural variables while perching guild (e.g., blackbirds, sparrows, meadowlarks) species richness was correlated with isolation, hydroperiod, and area annually. Overall predator and all guild species richness measures were also correlated with patch area for all seasons. These results suggest that while a complex mixture of patch area, hydroperiod and isolation influence habitat utilization that varies by season and at the community, guild and individual species level, the underlying predictors that define habitat use in wetlands annually includes hydroperiod, and is not exclusively patch area. Additionally, seasonal differences in predator species richness were found to be significant in some cases indicating that future avian population studies may benefit by sampling outside of the normally studied spring breeding season. Results of this study support the use of predator species richness as a suitable assay of metacommunity connectivity of prey species. Applications and implications of this approach toward future conservation efforts are discussed.
Show less - Date Issued
- 2007
- Identifier
- CFE0001766, ucf:47253
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001766
- Title
- DETERMINATION OF THE HYDROGEN PEROXIDE CONCENTRATION IN ROTENONE INDUCED DOPAMINERGIC CELLS USING CYCLIC VOLTAMMETRY AND AMPLEX® RED.
- Creator
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Patel, Kishan, Kim, Yoon, University of Central Florida
- Abstract / Description
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Parkinson's disease (PD) is a neurodegenerative condition that affects millions of people worldwide. The exact etiology of PD is unknown. However, it is well established that environmental factors contribute to the onset of PD. In particular, chemicals such as the insecticide Rotenone have been shown to increase the death of dopaminergic (DA) neurons by increasing levels of reactive oxygen species (ROS). ROS such as hydrogen peroxide (H2O2) have been shown to be elevated above basal levels in...
Show moreParkinson's disease (PD) is a neurodegenerative condition that affects millions of people worldwide. The exact etiology of PD is unknown. However, it is well established that environmental factors contribute to the onset of PD. In particular, chemicals such as the insecticide Rotenone have been shown to increase the death of dopaminergic (DA) neurons by increasing levels of reactive oxygen species (ROS). ROS such as hydrogen peroxide (H2O2) have been shown to be elevated above basal levels in PD patients. Currently, to measure H2O2 concentrations, a commercially available (Amplex® Red) fluorescent assay is used. However, the assay has limitations: it is not completely specific to hydrogen peroxide and can only measure extracellular ROS concentrations. This research focuses on testing an electrochemical sensor that uses cyclic voltammetry to quantitatively determine concentrations of H2O2 released from a cell culture. The sensor was first tested in normal cell culture conditions. Next, chemical interference was reduced and the sensor was optimized for accuracy by altering protein concentrations in the media. Finally, Rotenone was added to a cell culture to induce H2O2 production. Near real-time measurements of H2O2 were taken using the sensor and comparisons made to the fluorescent assay method. Overall, we are trying to determine if the electrochemical sensor can selectively and quantitatively measure H2O2 released from cells. Being able to track the production, migration and concentration of H2O2 in a cell can help researchers better understand its mechanism of action in cell death and oxidative damage, thus getting closer to finding a cure for PD.
Show less - Date Issued
- 2012
- Identifier
- CFH0004222, ucf:44921
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004222
- Title
- REMOTE SENSING WITH COMPUTATIONAL INTELLIGENCE MODELLING FOR MONITORING THE ECOSYSTEM STATE AND HYDRAULIC PATTERN IN A CONSTRUCTED WETLAND.
- Creator
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Mohiuddin, Golam, Chang, Ni-bin, Lee, Woo Hyoung, Wanielista, Martin, University of Central Florida
- Abstract / Description
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Monitoring the heterogeneous aquatic environment such as the Stormwater Treatment Areas (STAs) located at the northeast of the Everglades is extremely important in understanding the land processes of the constructed wetland in its capacity to remove nutrient. Direct monitoring and measurements of ecosystem evolution and changing velocities at every single part of the STA are not always feasible. Integrated remote sensing, monitoring, and modeling technique can be a state-of-the-art tool to...
Show moreMonitoring the heterogeneous aquatic environment such as the Stormwater Treatment Areas (STAs) located at the northeast of the Everglades is extremely important in understanding the land processes of the constructed wetland in its capacity to remove nutrient. Direct monitoring and measurements of ecosystem evolution and changing velocities at every single part of the STA are not always feasible. Integrated remote sensing, monitoring, and modeling technique can be a state-of-the-art tool to estimate the spatial and temporal distributions of flow velocity regimes and ecological functioning in such dynamic aquatic environments. In this presentation, comparison between four computational intelligence models including Extreme Learning Machine (ELM), Genetic Programming (GP) and Artificial Neural Network (ANN) models were organized to holistically assess the flow velocity and direction as well as ecosystem states within a vegetative wetland area. First the local sensor network was established using Acoustic Doppler Velocimeter (ADV). Utilizing the local sensor data along with the help of external driving forces parameters, trained models of ELM, GP and ANN were developed, calibrated, validated, and compared to select the best computational capacity of velocity prediction over time. Besides, seasonal images collected by French satellite Pleiades have been analyzed to address the seasonality effect of plant species evolution and biomass changes in the constructed wetland. The key finding of this research is to characterize the interactions between geophysical and geochemical processes in this wetland system based on ground-based monitoring sensors and satellite images to discover insight of hydraulic residence time, plant species variation, and water quality and improve the overall understanding of possible nutrient removal in this constructed wetland.
Show less - Date Issued
- 2014
- Identifier
- CFE0005533, ucf:52864
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005533
- Title
- Development of a Single Sensor Approach for Capturing Three-Dimensional, Time Resolved Flame and Velocity Information.
- Creator
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Reyes, Jonathan, Ahmed, Kareem, Kassab, Alain, Kapat, Jayanta, University of Central Florida
- Abstract / Description
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Performing non-intrusive measurements is the key to acquiring accurate information representative of what is being observed. The act of measuring often changes the environment being observed altering the information that is being obtained. Due to this, the community of fluid scientists have gravitated towards using laser-based measurements to observe the phenomena occurring in their experiments. The study of fluids has advanced since this point, utilizing techniques such as planar laser...
Show morePerforming non-intrusive measurements is the key to acquiring accurate information representative of what is being observed. The act of measuring often changes the environment being observed altering the information that is being obtained. Due to this, the community of fluid scientists have gravitated towards using laser-based measurements to observe the phenomena occurring in their experiments. The study of fluids has advanced since this point, utilizing techniques such as planar laser induced florescence (PLIF), particle image velocimetry (PIV), laser doppler velocimetry (LDV), particle doppler anemometry (PDA), etc. to acquire chemical species information and velocity information. These techniques, though, are inherently two-dimensional and cannot fully describe a flow field. In the area of reacting flow fields (combustion) acquiring the local fuel to air ratio information is increasingly important. Without it, scientist must rely on global one-dimensional metering techniques to correlate the fuel to air ratio of their flow field of interest. By knowing the fuel to air ratio locally and spatially across a flame, the location of products and reactants can be deduced, giving insight into any inefficiencies associated with a burner. Knowing the spatial fuel air field also gives insights into the density gradient associated with the flow field. Discussed in this work will be the development of a non-intrusive local fuel-air measurement technique and an expansion of the PIV technique into the third dimension, tomographic PIV, utilizing only one camera to do so for each measurement. The local fuel-air measurement is performed by recording two species (C2* and CH*) simultaneously and calibrating their ratio to the known fuel-air field. Tomographic PIV is performed by utilizing fiber coupling to acquire multiple viewpoints utilizing a single camera.
Show less - Date Issued
- 2019
- Identifier
- CFE0007523, ucf:52602
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007523
- Title
- HABITAT USE BY THE SOUTHEASTERN BEACH MOUSE (PEROMYSCUS POLIONOTUS NIVEIVENTRIS) AT CAPE CANAVERAL AIR FORCE STATION, FLORIDA.
- Creator
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Simmons, Kathryn, Stout, I. Jack, University of Central Florida
- Abstract / Description
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Successful recovery of the federally threatened southeastern beach mouse (Peromyscus polionotus niveiventris) depends in part on an understanding of their habitat requirements. I studied habitat use by beach mice at Cape Canaveral Air Force Station, Florida from March 2005 until March 2006. I livetrapped six grids, three on coastal dunes and three within scrub located inland from the coast. On each grid and trap station, I quantified the extent of bare ground, woody vegetation, non-woody...
Show moreSuccessful recovery of the federally threatened southeastern beach mouse (Peromyscus polionotus niveiventris) depends in part on an understanding of their habitat requirements. I studied habitat use by beach mice at Cape Canaveral Air Force Station, Florida from March 2005 until March 2006. I livetrapped six grids, three on coastal dunes and three within scrub located inland from the coast. On each grid and trap station, I quantified the extent of bare ground, woody vegetation, non-woody vegetation, height of vegetation, and percentage of coarse sand in the surface soil. I assessed trap success relative to these habitat variables using linear and multiple regression, correlation, and ordination. Significantly higher numbers of mice were captured in the scrub habitat relative to the coastal habitat. Linear regression of trap success against the habitat variables did not reveal any significant relationships at the level of grids. A non-metric multidimensional scaling model was designed to capture the vegetation heterogeneity at the trapping sites and clarify the results. This methodology identified a predominantly dune and predominately scrub cluster of trap sites. A bubble plot showed higher densities of beach mice using the scrub habitat types. These results suggest beach mice are selecting for those habitat variables defined by the ordination: higher vegetation height, more woody vegetation types, less bare ground, and less heterogeneity.
Show less - Date Issued
- 2009
- Identifier
- CFE0002605, ucf:48271
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002605
- Title
- Cerium Oxide Nanoparticles Sensitize Pancreatic Cancer Cells to Radiation by Promoting Acidic pH, ROS, and JNK Dependent Apoptosis.
- Creator
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Wason, Melissa, Zhao, Jihe, Self, William, Altomare, Deborah, Baker, Cheryl, University of Central Florida
- Abstract / Description
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Side effects of radiation therapy (RT) remain the most challenging issue for pancreatic cancer treatment. In this report we determined whether and how cerium oxide nanoparticles (CONPs) sensitize pancreatic cancer cells to RT. CONP pretreatment enhanced radiation-induced reactive oxygen species (ROS) production preferentially in acidic cell-free solutions as well as acidic human pancreatic cancer cells. In acidic environments, CONPs favor the scavenging of superoxide radical over the hydroxyl...
Show moreSide effects of radiation therapy (RT) remain the most challenging issue for pancreatic cancer treatment. In this report we determined whether and how cerium oxide nanoparticles (CONPs) sensitize pancreatic cancer cells to RT. CONP pretreatment enhanced radiation-induced reactive oxygen species (ROS) production preferentially in acidic cell-free solutions as well as acidic human pancreatic cancer cells. In acidic environments, CONPs favor the scavenging of superoxide radical over the hydroxyl peroxide resulting in accumulation of the latter whereas in neutral pH CONPs scavenge both. CONP treatment prior to RT markedly potentiated the cancer cell apoptosis both in culture and in tumors and the inhibition of the pancreatic tumor growth without harming the normal tissues or host mice. Mechanistically, CONPs were not able to significantly impact RT-induced DNA damage in cancer cells, thereby ruling out sensitization through increased mitotic catastrophe. However, JNK activation, which is known to be a key driver of RT-induced apoptosis, was significantly upregulated by co-treatment with CONPs and RT in pancreatic cancer cells in vitro and human pancreatic tumors in nude mice in vivo compared to CONPs or RT treatment alone. Further, CONP-driven increase in RT-induced JNK activation was associated with marked increases in Caspase 3/7 activation, indicative of apoptosis. We have shown CONPs increase ROS production in cancer cells; ROS has been shown to drive the oxidation of thioredoxin (TRX) 1 which results in the activation of Apoptosis Signaling Kinase (ASK) 1. The dramatic increase in ASK1 activation following the co-treatment of pancreatic cancer cells with CONPs followed by RT in vitro suggests that increased the c-Jun terminal kinase (JNK) activation is the result of increased TRX1 oxidation. The ability of CONPs to sensitize pancreatic cancer cells to RT was mitigated when the TRX1 oxidation was prevented by mutagenesis of a cysteine residue, or the JNK activation was blocked by an inhibitor,. Additionally, angiogenesis in pancreatic tumors treated with CONPs and RT was significantly reduced compared to other treatment options. Taken together, these data demonstrate an important role and mechanisms for CONPs in specifically killing cancer cells and provide novel insight into the utilization of CONPs as a radiosensitizer and therapeutic agent for pancreatic cancer.
Show less - Date Issued
- 2013
- Identifier
- CFE0005116, ucf:50725
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005116
- Title
- Simultaneous Imaging of the Diatomic Carbon and Methylidyne Species Radicals for the Quantification of the Fuel to Air Ratio from Low to High Pressure Combustion.
- Creator
-
Reyes, Jonathan, Ahmed, Kareem, Kassab, Alain, Kapat, Jayanta, University of Central Florida
- Abstract / Description
-
The radical intensity ratio of the diatomic carbon to methylidyne was characterized at initialpressures up to 10 bar using certified gasoline of 93% octane. This gasoline was selected due toits availability as a common fuel. The characterization of the radical intensity ratio of gasoline atelevated pressures enabled the creation of a calibration map of the equivalence ratio at enginerelevant conditions.The proposed calibration map acts as a feedback loop for a combustor. It allows for...
Show moreThe radical intensity ratio of the diatomic carbon to methylidyne was characterized at initialpressures up to 10 bar using certified gasoline of 93% octane. This gasoline was selected due toits availability as a common fuel. The characterization of the radical intensity ratio of gasoline atelevated pressures enabled the creation of a calibration map of the equivalence ratio at enginerelevant conditions.The proposed calibration map acts as a feedback loop for a combustor. It allows for thelocation of local rich and lean zones. The local information acquired can be used as an optimizationparameter for injection and ignition timings, and future combustor designs. The calibration map isapplicable at low and high engine loads to characterize a combustors behavior at all points in itsoperation map.Very little emphasis has been placed on the radical intensity ratio of unsteady flames,flames at high pressure, and liquid fuels. The current work performed the measurement on anunsteady flame ignited at different initial pressures employing a constant volume combustionchamber and liquid gasoline as the fuel source. The chamber can sustain a pressure rise of 200 barand allows for homogenous fuel to air mixtures.The results produced a viable calibration map from 1 to 10 bar. The intensity ratio at initialpressures above 5 bar behaved adversely in comparison to the lower pressure tests. The acquiredratios at the higher initial pressures are viable as individual calibration curves, but created anunexpected calibration map. The data shows promise in creating a calibration map that is usefulfor practical combustors.
Show less - Date Issued
- 2017
- Identifier
- CFE0006910, ucf:51692
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006910
