Environmental Engineering Commons^™

Near Infrared Fluorescent Single Walled Carbon Nanotubes As Tissue Localizable Biosensors, Nicole M. Iverson, Michael S. Strano, Nigel F. Strano, Thomas P. Mcnicholas

Biological Systems Engineering: Papers and Publications

A nanosensor for detecting an analyte can include a sub strate, a photoluminescent nanostructure, and a polymer interacting with the photoluminescent nanostructure. The nanosensor can be used in in vivo for biomedical applications.

Nitric Oxide Sensors For Biological Applications, Nicole M. Iverson, Eric M. Hofferber, Joseph A. Stapleton

Biological Systems Engineering: Papers and Publications

Nitric oxide (NO) is an essential signaling molecule within biological systems and is believed to be involved in numerous diseases. As a result of NO’s high reaction rate, the detection of the concentration of NO, let alone the presence or absence of the molecule, is extremely difficult. Researchers have developed multiple assays and probes in an attempt to quantify NO within biological solutions, each of which has advantages and disadvantages. This review highlights many of the current NO sensors, from those that are commercially available to the newest sensors being optimized in research labs, to assist in the understanding and …

Effects Of Subsurface Drainage Systems On Water And Nitrogen Footprints Simulated With Rzwqm2, Kristina J. Craft, Matthew J. Helmers, Robert W. Malone, Carl H. Pederson, Linda R. Schott

Biological Systems Engineering: Papers and Publications

Developing drainage water management (DWM) systems in the Midwest to reduce nitrogen (N) transport to the northern Gulf of Mexico hypoxic zone requires understanding of the long-term performance of these systems. Few studies have evaluated long-term impacts of DWM, and the simulation of controlled drainage (CD) with the Root Zone Water Quality Model (RZWQM) is limited, while shallow drainage (SD) has not been examined. We tested RZWQM using nine years (2007-2015) of field data from southeast Iowa for CD, SD, conventional drainage (DD), and undrained (ND) systems and simulated the long-term (1971-2015) impacts. RZWQM accurately simulated N loss in subsurface …

The Effects Of Long-Duration Subduction Earthquakes On Inelastic Behavior Of Bridge Pile Foundations Subjected To Liquefaction-Induced Lateral Spreading, Jonathan Nasr, Arash Khosravifar

Civil and Environmental Engineering Faculty Publications and Presentations

Effective-stress nonlinear dynamic analyses (NDA) were performed for a large-diameter reinforced concrete (RC) pile in multi-layered liquefiable sloped ground. The objective was to assess the effects of earthquake duration on the combination of inertia and liquefaction-induced lateral spreading. A parametric study was performed using input motions from subduction and crustal earthquakes covering a wide range of motion durations. The NDA results showed that the pile head displacements increased under liquefied conditions, compared to nonliquefied conditions, due to liquefaction-induced lateral spreading. The NDA results were used to develop a displacement-based equivalent static analysis (ESA) method that combines inertial and lateral spreading …

Value Added Products From Lignin And Biomass Derivatives, Chen Li

Civil & Environmental Engineering Theses & Dissertations

Pyrolysis is one of the traditional lignin and biomass utilization methods. The liquid products bio-oil and solid products bio-char are the main value-added products from lignin pyrolysis. Due to the narrow application and low quality, using the pyrolysis method to produce bio-oil and bio-char cannot bring sufficient economic benefits. In this dissertation, two methods were investigated to improve the quality of lignin bio-products.

Instead of direct pyrolysis, chemical activation (pyrolysis) was introduced in this dissertation. Compared to bio-char, the lignin chemical activation product lignin-activated-carbon has better economic value. With the best activation conditions, the lignin-activated-carbon produced a surface area of …

Pressure-Driven Stabilization Of Capacitive Deionization, Landon S. Caudill

Theses and Dissertations--Mechanical Engineering

The effects of system pressure on the performance stability of flow-through capacitive deionization (CDI) cells was investigated. Initial data showed that the highly porous carbon electrodes possessed air/oxygen in the micropores, and the increased system pressure boosts the gases solubility in saline solution and carries them out of the cell in the effluent. Upon applying a potential difference to the electrodes, capacitive-based ion adsorption occurs in competition with faradaic reactions that consume oxygen. Through the addition of backpressure, the rate of degradation decreases, allowing the cell to maintain its salt adsorption capacity (SAC) longer. The removal of oxygen from the …

Adaption Of Catechol And Reversible Addition-Fragmentation Chain-Transfer (Raft) Chemistries For Water-Based Applications, Olabode Oyeneye

Electronic Thesis and Dissertation Repository

Incorporating the binding chemistry of catechol functionality with RAFT chemistry offers a facile and simplified approach for developing a suite of new 2D and 3D hybrid materials with tailored morphologies. Leveraging both chemistries by synthesizing catechol-end functionalized RAFT agents and catechol-containing monomeric species for RAFT (co)polymerization, this dissertation examined a new series of advanced materials that were designed for water-based applications including model flocculants, thermoresponsive hydrogels, adsorbents and underwater adhesives.

To prepare the RAFT agents, novel trithiocarbonates with several catechol end R groups (as postpolymerization anchors) were synthesized that differ in their carbonyl α-substituents (Dopa-CTAs). These materials were evaluated for …

Moving Bed Biofilm Reactors: Evaluation Of Geometry, Attachment Surface Material And Biofilm Populations On The Uptake Of Ammonia And Synthetic Organic Contaminants In Wastewater., Patrick D. Mclee

Civil Engineering ETDs

Plastic biofilm carriers are used in biological wastewater treatment to encourage the attachment and retention of microorganisms that metabolize pollutants. The following research was conducted to better understand how different characteristics of the biofilm carrier affect the treatment performance of the attached biofilms in moving bed bioreactors. Lab scale reactors were used in this study to grow nitrifying biofilms in reactors with contrasting and controlled conditions. The effect of surface geometry on nitrification performance was evaluated by testing commercially available moving bed bioreactor media that contrast in physical design, and by varying operational parameters. Additionally, mature biofilm from a similar …

Multi-Scale Studies To Develop A Holistic Understanding Of Solid Fuel Combustion At Residential Scale, Sameer Patel

McKelvey School of Engineering Theses & Dissertations

Nearly 3 billion people rely on solid fuels for their cooking and heating needs, classifying them as “energy poor”. This poverty can be attributed to several factors, including a lack of resources (fuel), inefficient infrastructure (production and distribution), limited purchasing power (poverty), and ill-devised policies. Solid fuels, such as biomass, coal, and dung cakes, are burned in inefficient cookstoves. They generate products of incomplete combustion (PIC), such as CO, particulate matter (PM), and CH4, causing household air pollution (HAP) whose adverse impacts on both health and the environment have been well established.

HAP causes diseases such as chronic obstructive pulmonary …

Coupling Of Oxidation-Reduction Reactions Of Chromium, Iron And Manganese: Implications For The Fate And Mobility Of Chromium In Aquatic Environments, Chao Pan

McKelvey School of Engineering Theses & Dissertations

Both within the United States and internationally, hexavalent chromium (Cr(VI)) is a contaminant of concern in drinking water supplies. The U.S. Environmental Protection Agency is considering a Cr(VI)-specific standard. Thus improved technologies for Cr(VI) removal in drinking water are needed. Iron electrocoagulation for Cr(VI) removal was examined at conditions directly relevant to drinking water treatment, and humic acid (HA) affects the performance of electrocoagulation in multiple ways. The success of the chromium treatment or remediation also relies on the stability of the Cr(III)-containing solids with respect to reoxidation under groundwater conditions. Manganese is ubiquitous in aquatic and terrestrial environments, and …

Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed

Electronic Thesis and Dissertation Repository

The fast diminishing of fossil fuels in the near future, as well as the global warming caused by increasing greenhouse gases have motivated the urgent quest to develop advanced materials as cost-effective photoanodes for solar light harvesting and many other photocatalytic applications. Recently, titania nanotube arrays (TNTAs) fabricated by anodization process has attracted great interest due to their excellent properties such as: high surface area, vertically oriented, highly organized, one-dimensional, nanotubular structure, photoactivity, chemical stability and biocompatibility. This unique combination of excellent properties makes TNTAs an excellent photoanode for solar light harvesting. However, the relatively wide band gap energy of …

Modelling Of Future Flood Risk Across Canada Under Climate Change, Ayushi Gaur

Electronic Thesis and Dissertation Repository

Climate change has induced changes in key climate variables and hydrological cycle in Canada. In this study, future runoff projections made by 21 GCMs following four Representative Concentration Pathways (RCPs) are used as inputs into a macro-scaled hydrodynamic model: CaMa-Flood to simulate 25 km resolution daily streamflow across Canada for historical (1961-2005) and future (2061-2100) time-periods. Future changes in flood-hazard as a consequence of changes in flooding frequencies of historical 100-year and 250-year return period flood events, and changes in the month of occurrence of extreme flows are analyzed. Changes in flood risk at Canada’s 100 most populous cities and …

College Of Engineering Senior Design Competition Fall 2017, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge. The senior design competition helps focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects on …

Investigating Fate Of Silver Nanoparticles In Wastewater Biofilms, Connie Marie Walden

Graduate Theses and Dissertations

As industrial advances make everyday life easier for human kind, the processes by which we need to maintain sanitary conditions for both water and wastewater treatment will become increasingly complex. Innovations in food packaging and textile design incorporate engineered nanoparticles (ENPs) to increase antimicrobial properties of clothing, maintain product color, and keep food in packaging from spoilage. For most products, ENPs released will enter the sanitary sewer system, and ultimately wastewater treatment plants. Biofilms grow universally on surfaces where a protective layer of extracellular polymeric substances (EPS) shields attached cells from stressors. In wastewater treatment, complex biofilms are utilized as …

Real-Time, Selective Detection Of Heavy Metal Ions In Water Using 2d Nanomaterials-Based Field-Effect Transistors, Guihua Zhou

Theses and Dissertations

Excessive intake of heavy metals damages the central nervous system and causes brain and blood disorders in mammals. Heavy metal contamination is commonly associated with exposure to mercury, lead, arsenic, and cadmium (arsenic is a metalloid, but classified as a heavy metal). Traditional methods to detect heavy metal ions include graphite furnace atomic absorption spectroscopy (GFAAS), inductively-coupled plasma optical emission spectroscopy (ICP-OES), and inductively-coupled plasma mass spectroscopy (ICP-MS). Recently, many new methods have been proposed to detect heavy metal ions, including atomic absorption spectrometry, fluorescent sensors, colorimetric sensors, electrochemical sensors, X-ray absorption fine structure spectroscopy, ultrasensitive dynamic light scatting assays, …

Understanding The Long-Term Changes In Hydrologic Processes On A Watershed Scale Due To Climate Variability And Change, Chao Chen

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the past century, the population explosion and economic development have resulted in global warming, which has raised a series of concerns, such as sea-level rise, food security, and water resources management. The water flow patterns and features experience both short-term and long-term changes in responses to the changes in the hydrologic processes and meteorologic conditions. On a watershed scale, it is crucial to understand, quantify, and attribute the influences of climate change on the local water resources system. Such understanding can be of great help to undertake local water management tasks, such as flood control, reservoir operation, ecosystem services, …

Increase In The Reduction Potential Of Uranyl Upon Interaction With Graphene Oxide Surfaces, V. N. Bliznyuk, N. Conroy, Y. Xie, R. Podila, A. Rao, Brian A. Powell

Publications

Coordination of uranyl (U(VI)) with carboxylate groups on functionalized graphene oxide (GO) surfaces has been shown to alter the reduction potential of the sorbed uranium ion. A quantitative measure of the reduction potential and qualitative estimation of sorption/desorption processes were conducted using cyclic voltammetry, and the proposed coordination environment was determined using the surface sensitive attenuated total reflection mode of infrared spectroscopy (ATR-FTIR). GO is a nanostructured material possessing a large amount of oxygen-containing functional groups both on basal planes and at the edges, which can form strong surface complexes with radionuclides. The presence of these functional groups on the …

Setback Distance Requirements For Removal Of Swine Slurry Constituents In Runoff, John E. Gilley, Shannon L. Bartelt-Hunt, Kent M. Eskridge, Xu Li, Amy M. Schmidt, Daniel D. Snow

Biological Systems Engineering: Papers and Publications

The use of setback distances for manure application on cropland areas adjacent to surface water bodies could serve a function similar to vegetative filter strips. However, little information currently exists to identify the setback distances necessary to effectively reduce the transport of contaminants in runoff. The objective of this study was to determine the effects of setback distance and runoff rate on concentrations of selected constituents in runoff following land application of swine slurry to a no-till cropland area in southeast Nebraska. The study site had a residue cover of 7.73 Mg ha-1 and a slope gradient of 4.9%. The …

Geophysical Delineation Of Megaporosity And Fluid Migration Pathways For Geohazard Characterization Within The Delaware Basin, Culberson County, Texas, Jonathan David Woodard

Electronic Theses and Dissertations

ABSTRACT

Differential dissolution of gypsum karst within the Delaware Basin poses a significant threat to infrastructure that society depends on. The study area is located in Culberson County, Texas and traverses a distance of approximately 54 kilometers along RM 652 within the Gypsum Plain which is situated on the northern margin of the Chihuahua Desert and includes outcrops of Castile and Rustler strata that host karst geohazards. Regions of karst geohazard potential have been physically surveyed proximal to the study area in evaporites throughout the Castile Formation outcrop; minimal hazards, in comparison to the Castile Formation, have been documented in …

Water Chemistry Dynamics In Four Vernal Pools In Maine, Usa, Lydia H. Kifner

Electronic Theses and Dissertations

Vernal pools are small seasonal wetlands that are a common landscape feature that contribute to biodiversity in northeastern North American forests. However, even basic information about their biogeochemical functions, such as carbon cycling, is limited. Dissolved gas concentrations (CH₄, CO₂) and other water chemistry parameters were monitored weekly at the bottom and surface of four vernal pools in central and eastern Maine, USA, from April to August 2016. The vernal pools were supersaturated with respect to CH₄ and CO₂ at all sampling dates and locations. Concentrations of dissolved CH₄ and CO₂ ranged …