Physical Sciences and Mathematics Commons^™

Electricity Generation, Electricity Consumption, And Energy Efficiency In The United States: A Dual Climatic-Behavioral Approach, Christopher A. Craig

Graduate Theses and Dissertations

Much of the United States (US) has seen an increase in warm days, decrease in cool days, and increase in extreme weather events. These trends are projected to continue across much of the US and in turn increase the demand for electricity and subsequent greenhouse gas emissions. Ambitious energy efficiency (EE) programs are used across the US by energy utility organizations to reduce electricity demand and emissions. This study examined the impact of climatic variability on electricity consumption, as well as how pro-conservation interventions such as EE programs and experiential learning can be utilized to mitigate residential electricity consumption and …

Design Of A Nutrient Reclamation System For The Cultivation Of Microalgae For Biofuel Production And Other Industrial Applications, Heather Sandefur

Graduate Theses and Dissertations

Microalgal biomass has been identified as a promising feedstock for a number of industrial applications, including the synthesis of new pharmaceutical and biofuel products. However, there are several economic limitations associated with the scale up of existing algal production processes. Critical economic studies of algae-based industrial processes highlight the high cost of supplying essential nutrients to microalgae cultures. With microalgae cells having relatively high nitrogen contents (4 to 8%), the N fertilizer cost in industrial-scale production is significant. In addition, the disposal of the large volumes of cell residuals that are generated during product extraction stages can pose other economic …

Algal Wastewater Treatment And Biofuel Production: An Assessment Of Measurement Methods, And Impact Of Nutrient Availability And Species Composition, John F. Chamberlin

Graduate Theses and Dissertations

In order to move towards a more sustainable future, human civilization will need to decrease its impacts on air and water quality and minimize consumption of fossil fuels. Using algae for wastewater treatment and biofuel production offers one approach to progress towards these goals simultaneously. Algae are capable of removing nutrients from wastewater and carbon dioxide from the air, and the biomass formed in that process can be used to generate a wide-range of products including fertilizer or fuels that could power combustion engines, power plants, or zero-emission fuel cell vehicles. Using wastewater for biofuel production has the potential to …

The Mass Flux Of Non-Renewable Energy For Humanity, Edwin Dale Solomon

Graduate Theses and Dissertations

The global energy supply relies on non-renewable energy sources, coal, crude oil, and natural gas, along with nuclear power from uranium and these finite resources are located within the upper few kilometers of the Earth’s crust. The total quantity of non-renewable energy resources consumed relative to the total quantity available is an essential question facing humanity. Analyses of energy consumption was conducted for the period 1800 – 2014 using data from the U. S. Energy Information Administration (EIA) and World Energy Production, 1800-1985 to determine the balance between non-renewable energy resources consumed and ultimately recoverable reserves. Annual energy consumption was …

Modifying A Cow-Calf Biophysical Simulation Model For Analyses Of Alternative Enterprises, Jennifer L. Lutes

Graduate Theses and Dissertations

Cow-calf producers in the United States, tasked with providing beef calves for the beef industry, have had a multitude of difficulties to overcome in recent years. Producers in northwest Arkansas were negatively impacted by high hay prices coupled with low beef cattle market prices due to severe drought experienced in portions of 2010, 2011, and 2012. During this time they also faced high grain prices, due to a record low harvest, combined with portions of the corn harvest diverted from human and animal feed to ethanol production. Tight lending policies of this time, reminiscent of the housing market crash in …

Compounds Released From Biomass Deconstruction: Understanding Their Effect On Cellulose Enzyme Hydrolysis And Their Biological Activity, Angele Djioleu

Graduate Theses and Dissertations

The effect of compounds produced during biomass pretreatment on cellulolytic enzyme was investigated. Liquid prehydrolyzates were prepared by pretreating switchgrass using 24 combinations of temperature, time, and sulfuric acid concentration based on a full factorial design. Temperature was varied from 140°C to 180°C; time ranged from 10 to 40 min; and the sulfuric acid concentrations were 0.5% or 1% (v/v). Identified products in the prehydrolyzates included xylose, glucose, hydroxymethylfurfural (HMF), furfural, acetic acid, formic acid, and phenolic compounds at concentration ranging from 0 to 21.4 g/L. Pretreatment conditions significantly affected the concentrations of compounds detected in prehydrolyzates. When assayed in …

Synthesis Of Palladium And Palladium-Copper Nanostructures As Electrocatalysts, Haibin Wu

Graduate Theses and Dissertations

Pd and its alloys are alternatives of Pt as promising catalysts and electrocatalysts for many reactions. Size controlled synthesis of nanoparticles remains a major research subject, since smaller size particles show better catalytic performance. In this work, we developed a modified chemical wet method to prepare Pd and Pd-Cu nanostructures with uniform small size. Different sizes and shapes of Pd nanostructures were successfully synthesized by using the two reducing agents (i.e., L-ascorbyl-6-palmitate or phenylphosphinic acid). The reducing agents play a role to control the final morphologies and sizes of particles. The use of L-ascorbyl-6-palmitate favors to form irregular branch shapes …

Experimental Verification And Integration Of A Next Generation Smart Power Management System, Tavis Clemmer

Graduate Theses and Dissertations

With the increase in energy demand by the residential community in this country and the diminishing fossil fuel resources being used for electric energy production there is a need for a system to efficiently manage power within a residence. The Smart Green Power Node (SGPN) is a next generation energy management system that automates on-site energy production, storage, consumption, and grid usage to yield the most savings for both the utility and the consumer. Such a system automatically manages on-site distributed generation sources such as a PhotoVoltaic (PV) input and battery storage to curtail grid energy usage when the price …

Incorporating Environmental And Social Factors Into Decision-Making Of An Oil And Gas Industry To Improve Sustainability, Gaurav Dabhadkar

Graduate Theses and Dissertations

The energy industry (including the oil and gas industry) is facing unparalleled scrutiny and demands from stakeholders including investors, regulators (industry and environmental), communities, and other stakeholders. Sustainable development is one of the major concerns of the oil and gas industry. Companies are seeking to increase sustainability of their operations by considering environmental and Social concerns in addition to economic concerns. Oil and gas companies need to take decisions at different stages of the product life cycle (e.g. planning, design, exploration, production, and clean-up) which have direct or indirect impact on the organization's objectives. Addressing economic, technical, Social, and environmental …

Top-Down Aluminum Induced Crystallization For Photovoltaics, Seth Daniel Shumate

Graduate Theses and Dissertations

Passivating silicon solar cell surfaces is critical to fabricating very high efficiency and low cost photovoltaic devices. The sun-facing surface of the solar cell, known as the emitter, is particularly important when designing a solar cell. This work focused first on an alternative method of forming the emitter of silicon solar cells, and secondly on a method for improving the surface passivation of both these non-traditional and standard n-type solar cells.

Top-down aluminum induced crystallization (TAIC) was used for forming a polycrystalline silicon layer from amorphous silicon using aluminum to catalyze the crystallization at much lower temperatures than otherwise possible. …

Enhancement Of The Performance Of Gaas Based Solar Cells By Using Plasmonic, Anti-Reflection Coating And Hydrophobic Effects, Yahia Fayiz Makableh

Graduate Theses and Dissertations

Investigation of renewable energy resources is gaining huge momentum in recent years due to the limited fossil fuels, and their detriment impact on the environment. Solar energy is promising to meet the increased energy demand. In order to achieve this goal, solar energy has to be harvested efficiently at low cost. Therefore, higher efficiency solar cells are the primary focus of research worldwide. Photovoltaics based on InAs/GaAs intermediate band solar cells and their device performance enhancements are investigated in this dissertation. The device enhancement is carried out by surface modification methods. The dissertation work is inspired by the need of …

Transformation Of Swine Manure And Algal Consortia To Value-Added Products, Mahmoud A. Sharara

Graduate Theses and Dissertations

The swine production sector is projected to grow globally. In the past, this growth manifested itself in increased herd sizes and geographically concentrated production. Although economically sound, these trends had negative consequences on surrounding ecosystems. Over-application of manure resulted in water quality degradation, while long-term storage of manure slurries was found to promote release of potent GHG emissions. There is a need for innovative approaches for swine manure management that are compatible with current scales of production, and increasingly strict environmental regulations.

This study aims to investigate the potential for incorporating gasification as part of a novel swine manure management …

The Power Behind The Controversy: Understanding Local Policy Elites' Perceptions On The Benefits And Risks Associated With High Voltage Power Line Installation In The State Of Arkansas, Rachael Marie Moyer

Graduate Theses and Dissertations

Following a proposal for the installation of high voltage power lines in northwest Arkansas, a controversial policy debate emerged. Proponents of the transmission line argue that such an installation is inevitable and necessary to efficiently and reliably support the identified electric load in the region. Opponents claim that the lines will degrade the natural environment and hamper the tourism-based local economy in affected regions, notably in Ozark Mountain areas. This study seeks to understand how local policy elites perceive the benefits and risks associated with proposed transmission lines, which is a critical step in comprehending the formation and changes of …

Characterization Of Cellulase Enzyme Inhibitors Formed During The Chemical Pretreatments Of Rice Straw, Kalavathy Rajan

Graduate Theses and Dissertations

Production of fuels and chemicals from a renewable and inexpensive resource such as lignocellulosic biomass is a lucrative and sustainable option for the advanced biofuel and bio-based chemical platform. Agricultural residues constitute the bulk of potential feedstock available for cellulosic fuel production. On a global scale, rice straw is the largest source of agricultural residues and is therefore an ideal crop model for biomass deconstruction studies. Lignocellulosic biofuel production involves the processes of biomass conditioning, enzymatic saccharification, microbial fermentation and ethanol distillation, and one of the major factors affecting its techno-economic feasibility is the biomass recalcitrance to enzymatic saccharification. Preconditioning …

Identifying, Monitoring, Quantifying And Converting Algae To Bio-Fuels In Bio-Reactors, Alice C. Jernigan

Graduate Theses and Dissertations

Growing algae as a source for bio-fuels has become an area of interest due to concerns about global warming and the reliability and ecology of the production of fossil fuels. Dried algae harvested from a pilot water quality improvement technology at the Rockaway Wastewater Treatment Facility in New York were examined as a source of carbohydrates and lipids for the production of bio-fuels in bio-reactors. The length of storage time, storage conditions, sugar and lipid extraction processes, and fuel production were studied. The results show that if the algae is stored dry (0.015 g/g algae even after a year in …

Design Of A Pretreatment And Enzymatic Saccharification Scheme Of Understory From Managed Pine Forest For A Biochemical-Refinery Platform: The Example Of The Sweetgum Tree, Angele Djioleu

Graduate Theses and Dissertations

The possibility of using sweetgum from southern pine dominated forests as a biobased refinery feedstock was investigated. First, a baseline hydrolysis scheme for sweetgum wood and bark was designed. Sweetgum wood and bark were pretreated with 0.98% (v/v) sulfuric acid at 140°C for 30, 40, 50, 60 or 70 min and at 160°C for 30, 40, 50 or 60 min. The water insoluble solid (WIS) fraction was hydrolyzed with a cellulase enzyme cocktail. Results showed that maximum xylose and glucose yields from the wood were 82 and 86%, respectively. Similarly, the respective maximum yields of xylose and glucose from the …

The Development Of A High Performance Concrete To Store Thermal Energy For Concentrating Solar Power Plants, Emerson Esmond John

Graduate Theses and Dissertations

In recent years, due to rising energy costs as well as an increased awareness of the environmental effects of greenhouse gas emissions produced through traditional forms of energy production, there is great interest in developing alternative sources of energy. One of the most viable alternative energy sources is solar energy. In particular, concentrating solar power (CSP) technologies have been identified as an option for meeting utility needs in the U.S. Southwest. These systems are required to produce electricity not only during periods of high solar radiation but also during times of reduced radiation due to cloud cover, and even extend …

Energy Consumption And Greenhouse Gas Emissions From Commercial And Manufacturing Sectors Specific Studies On Hvac Equipment And Dairy Processing, Aik Jong Tan

Graduate Theses and Dissertations

Commercial and manufacturing sectors in United States consumed approximately 50% of the total End use energy in 2010. In 2009, 81.5% of the greenhouse gas (GHG) emitted in the United States was energy related. From the broad aspects of commercial and manufacturing sectors; two relatively narrow and specific topics, commercial building's HVAC equipment and dairy processing were chosen to increase the understanding of the energy use and GHG emission in these two sectors. Few published studies related to these two specific areas are available. The first study in this thesis discussed the energy use and GHG emissions by HVAC equipment …

Mathematical Modeling Of Fluid Spills In Hydraulically Fractured Well Sites, Oluwafemi Michael Taiwo

Graduate Theses and Dissertations

Improved drilling technology and favorable energy prices have contributed to the rapid pace at which the exploitation of unconventional natural gas is taking place across the United States. As a natural gas well is being drilled, reserve pits are constructed to hold the drilling fluids and other materials returned from the drilling process. These reserve pits can fail, and when they do, plant and animal life of the surrounding area may be adversely affected. This project develops a screening tool for a suitable location for a reserve pit. This work will be a critical piece of the Infrastructure Placement Analysis …

Identifying Optimal Cellulosic Biomass Feedstock Supply Areas For Potential Biorefineries In Arkansas, Mark Cooper

Graduate Theses and Dissertations

In February 2010, the U.S. Environmental Protection Agency released the revised Renewable Fuel Standard (RFS2), mandating at least 36 billion gallons of renewable fuels to be produced annually in America, and blended into all on/off road, locomotive, and marine gasoline and diesel by the year 2022. America's existing biorefineries fall significantly short of being able to meet this mandate, resulting in the need for rapid expansion in the near future if this goal is to be met. The state of Arkansas has abundant resources to offer the renewable energy industry, if properly utilized. The goal of this thesis is to …

Biological Strategies And Mathematical Approaches For Limiting Bacterial Contaminants And Chemical Pollutants In Bioethanol Fermentations, Alia Chahed Ep Limayem

Graduate Theses and Dissertations

During the most recent decades increased interest in fuel from biomass in the United States and worldwide has emerged each time petroleum derived-gasoline registered well publicized spikes in price. The willingness of the U.S. government to face the issues of more heavily high-priced foreign oil and climate change has led to more investment on plant-derived sustainable biofuel sources. Biomass derived from corn has become one of the primary feedstocks for bioethanol production for the past several years in the U.S. However, the argument of whether to use food as biofuel has led to a search for alternative non-food sources. Consequently, …