Physical Sciences and Mathematics Commons^™

Environmental Tradeoffs In Bioenergy Production And Agricultural Practices, Alicia Lynn English

Open Access Dissertations

The focus of this dissertation is the environmental tradeoffs of stover removal within the Corn Belt. The environmental tradeoffs considered are mainly concerned with managing soil erosion and soil quality. The analysis layers soil characteristics, management strategies and per acre costs using an integrated RUSLE2/WEPS model and an economic optimization model to illuminate a lower bound supply response. Different assumptions were tested in regards to sustainability, prices, and market integration for five states and 18,760 soil types throughout the Corn Belt. Sustainability was defined to limit soil erosion from wind and water to 5 tons/acre/year and the soil organic matter …

Direct And Indirect Greenhouse Gas Emissions From Biomass Storage: Implications For Life Cycle Assessment Of Biofuels, Isaac Robert Emery

Open Access Dissertations

Ethanol and other biofuels from cellulosic feedstocks are currently the most promising candidates to replace a large fraction of gasoline consumption in the United States and reduce greenhouse gas emissions. Gaps in current approaches to estimating the net greenhouse gas emissions from second-generation biofuels may lead to underestimation of the carbon intensity of these fuels. Current life cycle assessment models of biofuels do not sufficiently account for biomass losses and emissions associated with the harvest and storage of biomass feedstocks, which can require additional fuel and materials use on the farm as well as reducing the effective yield of a …

Electric Machine Differential For Vehicle Traction Control And Stability Control, Sandun Shivantha Kuruppu

Open Access Dissertations

Evolving requirements in energy efficiency and tightening regulations for reliable electric drivetrains drive the advancement of the hybrid electric (HEV) and full electric vehicle (EV) technology. Different configurations of EV and HEV architectures are evaluated for their performance. The future technology is trending towards utilizing distinctive properties in electric machines to not only to improve efficiency but also to realize advanced road adhesion controls and vehicle stability controls. Electric machine differential (EMD) is such a concept under current investigation for applications in the near future. Reliability of a power train is critical. Therefore, sophisticated fault detection schemes are essential in …

The Role Of Resource Predictability In The Metapopulation Dynamics Of Insects, Byju Nambidiyattil Govindan

Open Access Dissertations

The metapopulation paradigm has emerged as an important tool to understand the dynamics of species living in fragmented landscapes. In this dissertation, I investigate the unpredictable nature of resource availability for species living in human-dominated heterogeneous and dynamic landscapes in the context of its consequences for long-term regional persistence of species. In particular, I test theoretical advancements in metapopulation ecology following a two-pronged approach - via experiments in the lab and observations in the field - using insects. In chapter 1, I introduce the concept of metapopulation ecology in the context of its relevance for dynamics of species living in …

Long-Term Disturbance Histories Of Managed And Natural Mixed-Hardwood Forests Of Central Indiana, Robert Charles Morrissey

Open Access Dissertations

Over the course of the last century, we have observed changes in forest composition and structure related to changes in disturbance regimes. Reduced frequency and severity of disturbance events has allowed for the ingrowth of shade-tolerant, mesophytic species into forest understories; the result is shifting species compositions and changes in forest structure. In some cases, the loss of masting species, such as oak (Quercus spp.) and hickory (Carya spp.), may also accompany a shift in forest function and further accommodate other species shifts among mammal, insect, and bird populations. Management efforts have been suggested as a possible means …

Redefining The Operation And Design Considerations Of Organic Solar Cells: Role Of Morphology And Defect States, Biswajit Ray

Open Access Dissertations

Organic photovoltaic (OPV) technology is currently a topic of great interest for potentially low cost solar energy conversion and possibility of many novel PV applications (e.g., building-integrated PV, portable solar cells). Successful commercialization of this technology, however, will require significant improvement in efficiency and lifetime. In the last few years, innovation in novel polymer synthesis has raised the efficiency of OPV above 10%, at par with a-Si and earth-abundant solar cells. Further improvement in performance relies on breakthroughs in device design, which requires profound understanding of the physics of device operation. A major challenge in the design of the state …

Developing A Framework For Determining The Contribution Of Transportation Project To Sustainable Development, Karim Ahmed Abdel Warith

Open Access Dissertations

In the past few years, stakeholders in the transportation industry have been concerned with sustainability. However, transportation decision makers have had difficulty incorporating sustainability into transportation infrastructure decisions. This is mainly attributed to the vagueness of the term. Incorporating sustainability into transportation decision making has been a desire put forth by engineers for that past 10 years. However, with no apparent method of defining sustainability, designers and decision makers have not been able to fulfill this desire.

This investigation attempts to define sustainability in a comprehensive and quantitative manner. The research proposes a new methodology that relies on the objective …

The City In Mind: Environmental Literacy And Adaptation In Nineteenth-Century British Literature, Adam Edward Watkins

Open Access Dissertations

This dissertation argues that a new paradigm of selfhood emerged in nineteenth-century British literature, one that recognized the individual will and environmental influence not as antithetical but as dialectical forces in the formation of the self. The concept of an externally negotiated subject challenges both the inward and socially determined conceptions of self that have dominated the relevant criticism. Informed by empiricist, associationist, and evolutionary theories of the mind, the portrayals of subject-formation in this study highlight the radical changes occurring in the human environment in nineteenth-century, which catalyzed the conception of a malleable yet self-forming subject. Along with the …

Solar Cell Temperature Dependent Efficiency And Very High Temperature Efficiency Limits, John Robert Wilcox

Open Access Dissertations

Clean renewable solar energy is and will continue to be a critically important source of electrical energy. Solar energy has the potential of meeting all of the world's energy needs, and has seen substantial growth in recent years. Solar cells can convert sun light directly into electrical energy, and much progress has been made in making them less expensive and more efficient. Solar cells are often characterized and modeled at 25 °C, which is significantly lower than their peak operating temperature. In some thermal concentrating systems, solar cells operate above 300 °C. Since increasing the temperature drastically affects the terminal …

Quantifying Crop Yield, Bioenergy Production And Greenhouse Gas Emissions From Cropland And Marginal Land Using A Model-Data Fusion Approach, Zhangcai Qin

Open Access Dissertations

Bioenergy is becoming increasingly attractive to many countries, but has sparked an intensive debate regarding energy, economy, society and environment. Biofuels provide alternative energy to conventional fossil fuels. However, the environmental impact of producing and using biofuel is a major concern to our society. This study is dedicated to quantifying and evaluating biofuel production and potential climate change mitigation due to potential large-scale bioenergy expansion in the conterminous United States, using model-data fusion approaches.

Biofuel made from conventional (e.g., maize (Zea mays L.)) and cellulosic crops (e.g., switchgrass (Panicum virgatum L.) and Miscanthus (Miscanthus × giganteus)) …

Energy Systems Analysis For A Solar Economy, Dharik Sanchan Mallapragada

Open Access Dissertations

The use of solar energy for human needs faces challenges owing to its relatively low energy intensity and intermittent availability, coupled with the constrained availability of renewable carbon and land resources. This study uses systems analysis tools to identify carbon and energy efficient transformations of solar energy for different purposes, including transportation fuels and grid-scale energy storage. These efforts have been complemented with a feasibility analysis of existing fossil-energy and other hybrid pathways.

In an era of limited fossil resources, liquid fuels from sustainably available (SA) biomass could meet the energy needs of the transportation sector. We present a method …

An Experimental Investigation Of Wind Turbine Aerodynamic Interaction, Brandon Lee Ennis

Open Access Dissertations

Wind turbines have become a viable component in the overall energy makeup of the United States due to improved economics where energy prices have risen and production costs dropped. For a fixed cost, the effectiveness of a wind turbine financially is highly related to its performance. Considering the size of current wind farms, a minor performance improvement will result in large additional sums of revenue. A problem that has received attention with wind farms is that while the fixed costs of the development do get spread out further to reduce the installed cost of each wind turbine, the wind turbines …

An Analysis Of The Impact Of Storage Temperature, Moisture Content & Duration Upon The Chemical Components & Bioprocessing Of Lignocellulosic Biomass, Arun Athmanathan

Open Access Dissertations

The successful utilization of lignocellulosic biomass as a feedstock for fuels and chemicals necessitates storage for 2-6 months. It is correspondingly important to understand the impact of storage parameters - moisture concentration, temperature and duration - on biomass quality.

As aerobic storage is the most viable large-scale solution, aerobic storage experiments were carried out with three projected bioenergy feedstocks - sweet sorghum (Sorghum bicolor) bagasse, corn (Zea mays) stover and switchgrass (Panicum virgatum). Stored samples of each were examined for dry matter loss and composition change to develop a material balance around carbohydrates and lignin.

A mean dry matter loss …

Technology Agnostic Analysis And Design For Improved Performance, Variability, And Reliability In Thin Film Photovoltaics, Sourabh Dongaonkar

Open Access Dissertations

Thin film photovoltaics (TFPV) offer low cost alternatives to conventional crystalline Silicon (c-Si) PV, and can enable novel applications of PV technology. Their large scale adoption however, requires significant improvements in process yield, and operational reliability. In order to address these challenges, comprehensive understanding of factors affecting panel yield, and predictive models of performance reliability are needed. This has proved to be especially challenging for TFPV for two reasons in particular. First, TFPV technologies encompass a wide variety of materials, processes, and structures, which fragments the research effort. Moreover, the monolithic manufacturing of TFPV modules differs significantly from that of …

Understanding The Links Between Human Health And Climate Change: Agricultural Productivity And Allergenic Pollen Production Of Timothy Grass(Phleum Pratense L.) Under Future Predicted Levels Of Carbon Dioxide And Ozone, Jennifer M. Albertine

Open Access Dissertations

The prevalence of allergic disease is expected to increase with climate change. Grasses, which have highly allergenic pollen, are widely distributed across the globe. Changes in production and allergen content of grass pollen have not been specifically investigated. We tested the effects of elevated carbon dioxide and ozone on growth, pollen and allergen production of Timothy grass (Phleum pratense L.). Timothy is also used as an agricultural forage crop so changes in plant productivity can also affect humans indirectly. Plants were fumigated in eight chambers at two concentrations of ozone (O₃; 30 and 80 ppb) and carbon dioxide …

Ecohydrologic Impacts Of Climate And Land Use Changes On Watershed Systems: A Multi-Scale Assessment For Policy, Paul A. Ekness

Open Access Dissertations

Maintaining flows and quality of water resources is critical to support ecosystem services and consumptive needs. Understanding impacts of changes in climate and land use on ecohydrologic processes in a watershed is vital to sustaining water resources for multiple uses. This study completes a continental and regional scale assessment using statistical and simulation modeling to investigate ecohydrologic impacts within watershed systems.

Watersheds across the continental United States have diverse hydrogeomorphic characters, mean temperatures, soil moistures, precipitation and evaporation patterns that influence runoff processes. Changes in climate affect runoff by impacting available soil moisture, evaporation, precipitation and vegetative patterns. A one …

Transition Network: Exploring Intersections Between Culture, The Climate Crisis, And A Digital Network In A Community - Driven Global Social Movement, Emily Polk

Open Access Dissertations

The core aim of this research is to explore the communication processes of the Transition movement, a community-led global social movement as it adapted in a local context. The Transition movement facilitates community-led responses to the current global financial and climate crisis via the Transition Network, an online network that began in 2006, and is comprised of more than 2000 initiatives in 35 countries that have used the Transition model to start projects that use small-scale solutions to achieve greater sustainability. This research uses qualitative ethnographic methods and a theoretical framework based on actor network theory to better understand how …

Resilient Environmental Governance: Protecting Changing Ecosystems Through Multilevel Governance, Casey Stevens

Open Access Dissertations

International governance is increasingly defined by multilevel governance; with short-term projects, transnational cooperation between different groups, and unclear institutional space. In this situation, a key issue is the resilience of governance arrangements or the ability of governance arrangements to respond to political and ecological shocks to the system. Using international biodiversity governance, this study explores the question: What social and political processes produce resilient governance?

This study argues that the key to understanding resilient governance is the network structure within and outside of the governance arrangement. Modular network structures are able to generate ideas from multiple sources, able to solve …

Uncertainty In Climatic Change Impacts On Multiscale Watershed Systems, Olga V. Tsvetkova

Open Access Dissertations

Uncertainty in climate change plays a major role in watershed systems. The increase in variability and intensity in temperature and precipitation affects hydrologic cycle in spatial and temporal dimensions. Predicting uncertainty in climate change impacts on watershed systems can help to understand future climate-induced risk on watershed systems and is essential for designing policies for mitigation and adaptation. Modeling the temporal patterns of uncertainties is assessed in the New England region for temperature and precipitation patterns over a long term. The regional uncertainty is modeled using Python scripting and GIS to analyze spatial patterns of climate change uncertainties over space …

Fate Of 17Α-Estradiol, 17Β-Estradiol, And Estrone In Agricultural Soils And Sediments, Michael L. Mashtare Jr

Open Access Dissertations

The shift to concentrated animal production facilities and increasing rural-urban migration has increased the localized land application of nearly 1 billion tons of manure and biosolids annually. Although these applications provide nutrients and contribute to soil tilth, they also serve as a source for an estimated 49 tons of the natural manure-borne estrogens, 17α-estradiol (17α-E2), 17β-estradiol (17β-E2), and estrone (E1). While these estrogens are critical to endocrine systems, the low concentrations observed in the environment can disrupt endocrine function in non-target organisms, e.g., altering secondary sex characteristics which can lead to changes in wildlife communities.

Research presented here focuses on …