Engineering Commons^™

Effects Of Surrounding Water Table On A Forested Wetland Habitat In East Coast Of Virginia, Lane Stokes

Civil & Environmental Engineering Theses & Dissertations

Exchanges into and out of a wetland, including surface water flow, groundwater flow, and constituents in the flows, usually determine the wetland physicochemical characteristics and biodiversity. To date, of these three exchanges, groundwater flow is the least studied, particularly in the United States of America. In this thesis, field observations were conducted at a forested non-tidal wetland, located on a flat hilltop. The position of the wetland is such that groundwater outflow is the only significant exchange that could be impacted by the surrounding land use. In addition, a spatially variable steady-state model was set up to extrapolate the observations …

Longitudinal Tidal Dispersion Coefficient Estimation And Total Suspended Solids Transport Characterization In The James River, Beatriz Eugenia Patino

Civil & Environmental Engineering Theses & Dissertations

The longitudinal dispersion coefficient is a parameter used to evaluate the effect of cross-sectional variations on substance mixing mechanisms in estuaries influenced by tide, wind and internal density variations. Considering a two dimensional approach, this study aims at evaluating a tidal area of the lower James River at approximately 19 miles upstream from the mouth at the Chesapeake Bay, in the City of Newport News, and applies an experimental procedure based on in-situ salinity concentrations to estimate the dispersion coefficient in the area where receives a discharge from the HRSD James River Wastewater Treatment Plant, and further characterizes Total Suspended …

Environmental Efficiency Assessment Of U.S. Transport Sector: A Slack-Based Data Envelopment Analysis Approach, Yong Shin Park, Siew Hoon Lim, Gokhan Egilmez, Joseph Szmerekovsky

Mechanical and Industrial Engineering Faculty Publications

Sustainable transportation in the U.S. is essential for long-term economic growth and mobility, and environmental preservation. Using a non-radial slack-based measurement data envelopment analysis (SBM-DEA) model and state-level data, this study assesses the environmental efficiency of the transportation sector in the U.S. from years 2004 to 2012. In addition to environmental efficiency, carbon efficiency and potential carbon reduction were estimated for the 50 U.S. states. The findings of this study reveal that U.S. transportation sector was environmentally inefficient; U.S. states had an average transportation environmental efficiency score below 0.64. Therefore the states could substantially reduce carbon emissions to improve the …

Pyrolysis Of Dried Wastewater Biosolids Can Be Energy Positive, Patrick J. Mcnamara, Jon Koch, Zhongzhe Liu, Daniel Zitomer

Civil and Environmental Engineering Faculty Research and Publications

Pyrolysis is a thermal process that converts biosolids into biochar (a soil amendment), py-oil and py-gas, which can be energy sources. The objectives of this research were to determine the product yield of dried biosolids during pyrolysis and the energy requirements of pyrolysis. Bench-scale experiments revealed that temperature increases up to 500 °C substantially decreased the fraction of biochar and increased the fraction of py-oil. Py-gas yield increased above 500 °C. The energy required for pyrolysis was approximately 5-fold less than the energy required to dry biosolids (depending on biosolids moisture content), indicating that, if a utility already uses energy …

Wetlands And Coastal Systems: Protecting And Restoring Valuable Ecosystems, C. T. Agouridis, K. R. Douglas-Mankin, A. C. Linhoss, A. R. Mittelstet

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Wetlands and coastal systems are unique, highly productive, and often threatened landscapes that provide a host of services to both humans and the environment. This article introduces a five-article Wetlands and Coastal Systems Special Collection that evolved from a featured session at the 2015 ASABE Annual International Meeting in New Orleans, Louisiana. The Collection provides perspectives on tools and techniques for enhancing the protection and restoration of wetlands and coastal systems with emphasis on vegetation, hydrology, water quality, and planning. Topics span the Florida Everglades (two articles) and Virginia floodplain (one article) wetland systems and include remote sensing (one article) …

Minimum Conditions For Visible Mold Growth, G. A. Tsongas, Frank Riordan

Mechanical and Materials Engineering Faculty Publications and Presentations

Considerable confusion and misunderstanding exists over the conditions required for visible mold growth at a surface in buildings. That is evident in papers and articles authored by engineers and other scientists, including various ASHRAE, ASTM and Canada Mortgage Housing Corporation publications. One of the major problems is that many HVAC engineers, building scientists, practitioners and others believe there exists a single critical value of the relative humidity (RH) of the indoor or ambient air well away from surfaces, below which mold will not grow on surfaces. However, that is not the case. The purpose of this article is to clarify …

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 10 - Play 3 - 2016/06/15), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 1/2 - Play 3 - 2016/06/12), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 1 - Play 2 - 2016/06/07), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 1/3 - Play 1 - 2016/06/08), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 10 - Play 2 - 2016/06/14), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 1/3 - Play 2 - 2016/06/08), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 10 - Play 1 - 2016/06/10), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 1/2 - Play 3 - 2016/06/12), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 1 - Play 1 - 2016/06/07), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 12 - Play 2 - 2016/06/15), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment. To observe the difference in the assimilation of both isotopes of Carbon Dioxide.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 12 - Play 3 - 2016/06/16), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment. To observe the difference in the assimilation of both isotopes of Carbon Dioxide.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 11 - Play 2 - 2016/06/15), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment. To observe the difference in the assimilation of both isotopes of Carbon Dioxide.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 16 - Play 1 - 2016/06/20), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment. To observe the difference in the assimilation of both isotopes of Carbon Dioxide.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 11 - Play 1 - 2016/06/15), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment. To observe the difference in the assimilation of both isotopes of Carbon Dioxide.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 10/11 - Play 4 - 2016/06/21), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 10/11 - Play 4 - 2016/06/21), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 12 - Play 1 - 2016/06/15), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment. To observe the difference in the assimilation of both isotopes of Carbon Dioxide.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 16 - Play 2 - 2016/06/20), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment. To observe the difference in the assimilation of both isotopes of Carbon Dioxide.

Spatially Explicit Life Cycle Assessment: Opportunities And Challenges Of Wastewater-Based Algal Biofuels In The United States, Javad Roostaei, Yongli Zhang

Civil and Environmental Engineering Faculty Research Publications

This work presented a Spatially-Explicit-High-Resolution Life Cycle Assessment (SEHR-LCA) model for wastewater-based algal biofuel production, by integrating life cycle assessment, GIS analysis, and site-specific Wastewater Treatment Plants (WWTPs) data analysis. Wastewater resources, land availability, and meteorological variation were analyzed for algae cultivation. Three pathways, Microwave Pyrolysis, hydrothermal liquefaction, and lipid extraction were modeled for bio-oil conversion. This model enables the assessment of seasonal and site-specific variations in productivity and environmental impacts of wastewater-based algal bio-oil across the whole U.S. Model results indicate that wastewater-based algal bio-oil can provide an opportunity to increase national biofuel output. The potential production of algal …

Nanostructured Thin Film Synthesis By Aerosol Chemical Vapor Deposition For Energy Storage Applications, Tandeep Singh Chadha

McKelvey School of Engineering Graduate Student Theses & Dissertations

Renewable energy sources offer a viable solution to the growing energy demand while mitigating concerns for greenhouse gas emissions and climate change. This has led to a tremendous momentum towards solar and wind-based energy harvesting technologies driving efficiencies higher and costs lower. However, the intermittent nature of these energy sources necessitates energy storage technologies, which remain the Achilles heel in meeting the renewable energy goals. This dissertation focusses on two approaches for addressing the needs of energy storage: first, targeting direct solar to fuel conversion via photoelectrochemical water-splitting and second, improving the performance of current rechargeable batteries by developing new …

Nanoparticle Formation In The Flame Synthesis Of Multicomponent Nanostructured Materials For Clean Energy Applications, Jiaxi Fang

McKelvey School of Engineering Graduate Student Theses & Dissertations

This dissertation studies the initial stages of particle formation during the combustion synthesis of multicomponent nanomaterials. Combustion is commonly used for the production of nanomaterials at industrial scales and has advantages of high production rates, low waste generation, and scalability. However, there are limitations in being able to apply this synthesis approach to more advanced multicomponent systems. Gas to particle conversion in flames occurs through precursor decomposition, collisional growth, coagulation, condensation, and sintering. There is a fundamental gap in knowledge on the initial stages of particle formation in flames below 2nm due to measurement difficulties and instrumentation limitations. Using a …

Crumpled Graphene Oxide: Aerosol Synthesis And Environmental Applications, Yi Jiang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Environmental technologies, such as for water treatment, have advanced significantly due to the rapid expansion and application of nanoscale material science and engineering. In particular, two-dimensional graphene oxide (GO), has demonstrated considerable potential for advancing and even revolutionizing some of these technologies, such as engineered photocatalysts and membranes. To realize such potential, an industrially scalable process is needed to produce monomeric and aggregation-resistant GO nanostructures/composites, in addition to new knowledge of material properties, behavior, and performance within an environmental context.

Research presented in this thesis addresses both scientific and engineering gaps through the development of a simple, yet robust aerosol-based …

Calcium Carbonate Formation In Energy-Related Subsurface Environments And Engineered Systems, Qingyun Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

Geologic CO2 sequestration (GCS) in subsurface saline aquifers is a promising strategy to mitigate climate change caused by increasing anthropogenic CO2 emissions from energy production. At GCS sites, interactions between fluids and geomedia are important because they can affect CO2 trapping efficiency and the safety of CO2 storage. These interactions include the dissolution and precipitation of minerals. One of the most important minerals is calcium carbonate, because it can permanently trap CO2.

In this work, Portland cement was used as a model geomedium to investigate the chemical reactions, mechanical alterations, transport of reactive fluids, and the interplay of all these …

Pore Scale Transport Of Miscible And Immiscible Fluids In Porous Media, Tolulope O. Odimayomi, Arezoo M. Ardekani

The Summer Undergraduate Research Fellowship (SURF) Symposium

The separation of harmful or valuable substances entrapped in porous media has applications in processes such as enhanced oil recovery, diffusion in tissue, and aquifer remediation. In this study the motion and removal rate of immiscible and miscible solutions have been analyzed to gain understanding of solvent effectiveness as it is diluted due to diffusion or mixing within porous materials. The extraction of oil using water, a surfactant solution of 4% CTAB in water, and a foam produced form the surfactant solution is observed using two dimensional flows between parallel slides containing cylindrical obstacles. The fluid motion is visualized. The …