Matching Items (129)
Description
Rabies disease remains enzootic among raccoons, skunks, foxes and bats in the United States. It is of primary concern for public-health agencies to control spatial spread of rabies in wildlife and its potential spillover infection of domestic animals and humans. Rabies is invariably fatal in wildlife if untreated, with a non-negligible incubation period. Understanding how this latency affects spatial spread of rabies in wildlife is the concern of chapter 2 and 3. Chapter 1 deals with the background of mathematical models for rabies and lists main objectives. In chapter 2, a reaction-diffusion susceptible-exposed-infected (SEI) model and a delayed diffusive susceptible-infected (SI) model are constructed to describe the same epidemic process -- rabies spread in foxes. For the delayed diffusive model a non-local infection term with delay is resulted from modeling the dispersal during incubation stage. Comparison is made regarding minimum traveling wave speeds of the two models, which are verified using numerical experiments. In chapter 3, starting with two Kermack and McKendrick's models where infectivity, death rate and diffusion rate of infected individuals can depend on the age of infection, the asymptotic speed of spread $c^\ast$ for the cumulated force of infection can be analyzed. For the special case of fixed incubation period, the asymptotic speed of spread is governed by the same integral equation for both models. Although explicit solutions for $c^\ast$ are difficult to obtain, assuming that diffusion coefficient of incubating animals is small, $c^\ast$ can be estimated in terms of model parameter values. Chapter 4 considers the implementation of realistic landscape in simulation of rabies spread in skunks and bats in northeast Texas. The Finite Element Method (FEM) is adopted because the irregular shapes of realistic landscape naturally lead to unstructured grids in the spatial domain. This implementation leads to a more accurate description of skunk rabies cases distributions.
ContributorsLiu, Hao (Author) / Kuang, Yang (Thesis advisor) / Jackiewicz, Zdzislaw (Committee member) / Lanchier, Nicolas (Committee member) / Smith, Hal (Committee member) / Thieme, Horst (Committee member) / Arizona State University (Publisher)
Created2013
Description
Bacteriophage (phage) are viruses that infect bacteria. Typical laboratory experiments show that in a chemostat containing phage and susceptible bacteria species, a mutant bacteria species will evolve. This mutant species is usually resistant to the phage infection and less competitive compared to the susceptible bacteria species. In some experiments, both susceptible and resistant bacteria species, as well as phage, can coexist at an equilibrium for hundreds of hours. The current research is inspired by these observations, and the goal is to establish a mathematical model and explore sufficient and necessary conditions for the coexistence. In this dissertation a model with infinite distributed delay terms based on some existing work is established. A rigorous analysis of the well-posedness of this model is provided, and it is proved that the susceptible bacteria persist. To study the persistence of phage species, a "Phage Reproduction Number" (PRN) is defined. The mathematical analysis shows phage persist if PRN > 1 and vanish if PRN < 1. A sufficient condition and a necessary condition for persistence of resistant bacteria are given. The persistence of the phage is essential for the persistence of resistant bacteria. Also, the resistant bacteria persist if its fitness is the same as the susceptible bacteria and if PRN > 1. A special case of the general model leads to a system of ordinary differential equations, for which numerical simulation results are presented.
ContributorsHan, Zhun (Author) / Smith, Hal (Thesis advisor) / Armbruster, Dieter (Committee member) / Kawski, Matthias (Committee member) / Kuang, Yang (Committee member) / Thieme, Horst (Committee member) / Arizona State University (Publisher)
Created2012
Description
In vertebrate outer retina, changes in the membrane potential of horizontal cells affect the calcium influx and glutamate release of cone photoreceptors via a negative feedback. This feedback has a number of important physiological consequences. One is called background-induced flicker enhancement (BIFE) in which the onset of dim background enhances the center flicker response of horizontal cells. The underlying mechanism for the feedback is still unclear but competing hypotheses have been proposed. One is the GABA hypothesis, which states that the feedback is mediated by gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter released from horizontal cells. Another is the ephaptic hypothesis, which contends that the feedback is non-GABAergic and is achieved through the modulation of electrical potential in the intersynaptic cleft between cones and horizontal cells. In this study, a continuum spine model of the cone-horizontal cell synaptic circuitry is formulated. This model, a partial differential equation system, incorporates both the GABA and ephaptic feedback mechanisms. Simulation results, in comparison with experiments, indicate that the ephaptic mechanism is necessary in order for the model to capture the major spatial and temporal dynamics of the BIFE effect. In addition, simulations indicate that the GABA mechanism may play some minor modulation role.
ContributorsChang, Shaojie (Author) / Baer, Steven M. (Thesis advisor) / Gardner, Carl L (Thesis advisor) / Crook, Sharon M (Committee member) / Kuang, Yang (Committee member) / Ringhofer, Christian (Committee member) / Arizona State University (Publisher)
Created2012
Description
Lean and Green construction methodologies are prevalent in today's construction industry. Green construction implementation in buildings has progressed quickly due to the popularity and development of building rating systems, such as LEED, Green Globes, and the Living Building Challenge. Similarly, lean construction has become more popular as this philosophy often leads to efficient construction and improved owner satisfaction. Green construction is defined as using sustainable materials in the construction process to eliminate environmental degradation and ensure that material and equipment use aligns with the design intent and promotes efficient building performance. Lean construction is defined as a set of operational/systematic processes that reduce waste and eliminates defects in the project process throughout its lifecycle. This paper describes the implementation of Lean and Green construction processes to determine the trends that each methodology contributes to a project as well as how these methodologies synergize. The authors identified common elements of each methodology through semi-structured interviews with several construction industry professionals who had extensive experience with lean and green construction. Interviewees report lean and green construction philosophies are different "flavors" of the industry; however, interviewees also state if implemented together, these processes often result in a high-performance building.
ContributorsMaris, Kelsey Lynn (Co-author) / Parrish, Kristen (Co-author, Thesis director) / Olson, Patricia (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / Del E. Webb Construction (Contributor)
Created2015-05
Description
As the demand for natural resources increases with population growth, importance has been placed on environmental issues due to increasing pressure on land, water, air, and raw materials. In order to sustain the environment and natural resources, sustainable engineering and earth systems engineering and management (ESEM) is vital for future populations. The Aral Sea and the Florida Everglades are both regions that are heavily impacted by human design decisions. Comparing and analyzing the implications and outcomes of these human design decisions allows conclusions to be made regarding how earth systems engineering and management can be best accomplished. The Aral Sea, located in central Asia between Kazakhstan and Uzbekistan, is a case study of an ecosystem that has collapsed under the pressure of agricultural expansion. This has caused extensive economic, health, agricultural, and environmental impacts. The Everglades in southern Florida is a case study where the ecosystem has evolved from its original state, rather than collapsed, due to human settlement and water resource demand. In order to determine effective sustainable engineering approaches, the case studies will be evaluated using ESEM principles. These principles are used as guidance in executing better practice of sustainable engineering. When comparing the two case studies, it appears that the Everglades is an adequate representation of effective ESEM approaches, while the Aral Sea is not reflective of effective approaches. When practicing ESEM, it is critical that the principles be applied as a whole rather than individually. While the ESEM principles do not guarantee success, they offer an effective guide to dealing with the complexity and uncertainty in many of today's systems.
ContributorsRidley, Brooke Nicole (Author) / Allenby, Brad (Thesis director) / Parrish, Kristen (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2015-12
Description
The objective for Under the Camper Shell was to build a prototype of a full living environment within the confines of a pickup truck bed and camper shell. The total volume available to work with is approximately 85ft3. This full living environment entails functioning systems for essential modern living, providing shelter and spaces for cooking, sleeping, eating, and sanitation. The project proved to be very challenging from the start. First, the livable space is extremely small, being only tall enough for one to sit up straight. The truck and camper shell were both borrowed items, so no modifications were allowed for either, e.g. drilling holes for mounting. The idea was to create a system that could be easily removed, transforming it from a camper to a utility truck. The systems developed for the living environment would be modular and transformative so to accommodate for different necessities when packing. The goal was to create a low-water system with sustainability in mind. Insulating the space was the largest challenge and the most rewarding, using body heat to warm the space and insulate from the elements. Comfort systems were made of high density foam cushions in sections to allow folding and stacking for different functions (sleeping, lounging, and sitting). Sanitation is necessary for healthy living and regular human function. A composting toilet was used for the design, lending to low-water usage and is sustainable over time. Saw dust would be necessary for its function, but upon composting, the unit will generate sufficient amounts of heat to act as a space heater. Showering serves the functions of exfoliation and ridding of bacteria, both of which bath wipes can accomplish, limiting massive volumes of water storage and waste. Storage systems were also designed for modularity. Hooks were installed the length of the bed for hanging or securing items as necessary. Some are available for hanging bags. A cabinetry rail also runs the length of the bed to allow movement of hard storage to accommodate different scenarios. The cooking method is called "sous-vide", a method of cooking food in air-tight bags submerged in hot water. The water is reusable for cooking and no dishes are necessary for serving. Overall, the prototype fulfilled its function as a full living environment with few improvements necessary for future use.
ContributorsLimsirichai, Pimwadee (Author) / Foy, Joseph (Thesis director) / Parrish, Kristen (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor) / School of Sustainability (Contributor)
Created2014-12
Description
Many student engagement studies take a holistic view of the student experience at a university setting, which includes factors both inside and outside of the classroom. However, most engagement improvements focus on activities outside of the classroom. Some research regarding improving teaching styles and activities shows an impact on engagement, but little research has investigated the impact of the built environment on student engagement. This paper explores the definition of student engagement, what environmental variables affect building occupant performance, and specifically addresses how environmental variables can impact student engagement. The authors provide a review of literature discussing these variables as well as propose a method for quantifying the impact of the built environment on students based on results of a preliminary study. Evidence of a relationship between human comfort and student engagement can provide an argument for how thoughtful building designs can improve student success and engineering education. It can further extend to industry settings where green building design can lower operating costs and improve worker satisfaction and productivity.
ContributorsDuggan, Kathleen Rose (Author) / Parrish, Kristen (Thesis director) / Khanna, Vikas (Committee member) / Beckert, Kimberly (Committee member) / Industrial, Systems (Contributor) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor)
Created2014-05
Description
The paper was written for the International Group for Lean Construction Conference in July 2013 in Fortaleza, Brazil.
With the advent of sustainable building ordinances in the United States and internationally, contractors are required to deliver sustainable projects but have historically not been considered partners in developing the sustainability goals and objectives for projects. Additionally, as alternative project delivery methods gain popularity, contractors have an opportunity and—in an increasing number of cases—a requirement, to take a larger role in sustainability efforts beyond the design phase. Understanding the contractor’s self-perceived role in this industry is imperative to informing their future role in the sustainable construction industry. This paper presents data and analysis of a survey of general contractors in the Phoenix, Arizona market that asked for their opinions and viewpoints regarding sustainable construction. Respondents provided feedback about corporate profitability, growth forecast, and the perceived efficiency of the U.S Green Building Council’s LEED rating system. The survey also queried contractors about current and future work breakdown structures for sustainable project delivery as well as their underlying motives for involvement in these projects.
Academics from Arizona State University worked with local industry to develop the survey in 2012 and the survey was deployed in 2013. We sent the survey to 76 contractors and received responses from 21, representing a 27.6% response rate. Respondents include representatives from general contractors, mechanical contractors, and electrical contractors, among others. This paper presents the responses from general contractors as they typically have most contact with the owner and design teams.
With the advent of sustainable building ordinances in the United States and internationally, contractors are required to deliver sustainable projects but have historically not been considered partners in developing the sustainability goals and objectives for projects. Additionally, as alternative project delivery methods gain popularity, contractors have an opportunity and—in an increasing number of cases—a requirement, to take a larger role in sustainability efforts beyond the design phase. Understanding the contractor’s self-perceived role in this industry is imperative to informing their future role in the sustainable construction industry. This paper presents data and analysis of a survey of general contractors in the Phoenix, Arizona market that asked for their opinions and viewpoints regarding sustainable construction. Respondents provided feedback about corporate profitability, growth forecast, and the perceived efficiency of the U.S Green Building Council’s LEED rating system. The survey also queried contractors about current and future work breakdown structures for sustainable project delivery as well as their underlying motives for involvement in these projects.
Academics from Arizona State University worked with local industry to develop the survey in 2012 and the survey was deployed in 2013. We sent the survey to 76 contractors and received responses from 21, representing a 27.6% response rate. Respondents include representatives from general contractors, mechanical contractors, and electrical contractors, among others. This paper presents the responses from general contractors as they typically have most contact with the owner and design teams.
ContributorsHolloway, Skyler Brock (Author) / Parrish, Kristen (Thesis director) / Bashford, Howard (Committee member) / Meek, Jeremy (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / W. P. Carey School of Business (Contributor) / Del E. Webb Construction (Contributor)
Created2013-05
Description
Due to the environmental necessity, solar panel technology continues to be developed and is appropriate for residences. Solar installers have developed financially accessible options for installing solar, primarily through leasing. The Arizona residential solar module industry has grown and is competitive. Four solar installers, SolarCity, Sunrun, SunPower, and Sungevity, are leaders in the industry nationally and statewide and possess many effective marketing strategies along with some opportunities for improvement. SolarCity offers financing options and is full-service. It is the largest residential solar company that others tend to emulate. Sunrun is more unconventional but has a president who has helped its marketing with her appearances. SunPower runs a network of local solar dealers and takes a hands-off approach to the process. Sungevity has the potential to learn from these installers and can enhance its brand even further. It can focus on targeting young, new homeowners and can follow Apple's style of clean and concise materials. By emphasizing customer service, using guerilla marketing techniques, and following Cialdini's theories on persuasion and influence, Sungevity can be the leader in the Arizona residential solar module industry.
ContributorsMagerman, Hayley (Author) / Parrish, Kristen (Committee member) / Barrett, The Honors College (Contributor)
Created2013-12
Description
In this research we consider stochastic models of Glioblastoma Multiforme brain tumors. We first look at a model by K. Swanson et al., which describes the dynamics as random diffusion plus deterministic logistic growth. We introduce a stochastic component in the logistic growth in the form of a random growth rate defined by a Poisson process. We show that this stochastic logistic growth model leads to a more accurate evaluation of the tumor growth compared its deterministic counterpart. We also discuss future plans to incorporate individual patient geometry, extend the model to three dimensions and to incorporate effects of different treatments into our model, in collaboration with a local hospital.
ContributorsManning, Michael Clare (Author) / Kostelich, Eric (Thesis director) / Kuang, Yang (Committee member) / Gardner, Carl (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / School of Letters and Sciences (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2013-12