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Articles 901 - 930 of 6110

Full-Text Articles in Environmental Engineering

Élimination Des Vapeurs Toxiques Par Oxydation : Développement De Procédures D'Évaluation Des Systèmes De Purification De L'Air Des Conduits De Ventilation, Chang-Seo Lee, Fariborz Haghighat, Alireza Haghighat Mamaghani, Zahra Shayegan, Ali Bahloul, Mélanie Huard, Lexuan Zhong, Mitra Bahr Oct 2022

Élimination Des Vapeurs Toxiques Par Oxydation : Développement De Procédures D'Évaluation Des Systèmes De Purification De L'Air Des Conduits De Ventilation, Chang-Seo Lee, Fariborz Haghighat, Alireza Haghighat Mamaghani, Zahra Shayegan, Ali Bahloul, Mélanie Huard, Lexuan Zhong, Mitra Bahr

Rapports de recherche scientifique

L'exposition à des composés organiques volatils (COV) dans les lieux de travail peut avoir des effets aigus, notamment sous forme d'irritation de la peau, des yeux, de la bouche et du nez. Certains produits peuvent également provoquer des effets chroniques, comme l'asthme et le cancer. La prévention de tels effets nocifs sur la santé des travailleurs par l'adoption et la mise en œuvre de mesures visant à en éliminer ou à tout le moins réduire le risque s'avère importante. Parmi les approches développées à ce jour pour réduire l'exposition aux polluants de l'air intérieur – dont les COV –, la …


Removal Of Toxic Vapors By Oxidation: Development Of Laboratory Test Procedures For In-Duct Air Cleaning Systems, Chang-Seo Lee, Fariborz Haghighat, Alireza Haghighat Mamaghani, Zahra Shayegan, Ali Bahloul, Mélanie Huard, Lexuan Zhong, Mitra Bahr Oct 2022

Removal Of Toxic Vapors By Oxidation: Development Of Laboratory Test Procedures For In-Duct Air Cleaning Systems, Chang-Seo Lee, Fariborz Haghighat, Alireza Haghighat Mamaghani, Zahra Shayegan, Ali Bahloul, Mélanie Huard, Lexuan Zhong, Mitra Bahr

Rapports de recherche scientifique

L'exposition à des composés organiques volatils (COV) dans les lieux de travail peut avoir des effets aigus, notamment sous forme d'irritation de la peau, des yeux, de la bouche et du nez. Certains produits peuvent également provoquer des effets chroniques, comme l'asthme et le cancer. La prévention de tels effets nocifs sur la santé des travailleurs par l'adoption et la mise en œuvre de mesures visant à en éliminer ou à tout le moins réduire le risque s'avère importante. Parmi les approches développées à ce jour pour réduire l'exposition aux polluants de l'air intérieur – dont les COV –, la …


Large Eddy Simulations Of Wind Shear From Passing Vehicles Under A Freeway Overpass, Hamid Rahai, Assma Begum Oct 2022

Large Eddy Simulations Of Wind Shear From Passing Vehicles Under A Freeway Overpass, Hamid Rahai, Assma Begum

Mineta Transportation Institute

California is moving toward a 100% clean energy future, and expanded wind energy will be a major component of the state’s future energy portfolio. Innovations in wind energy resources will move California closer to achieving its goal. To gain a better understanding of transient pressure and the wind shear generated at the bridge poles from passing vehicles, this study performed large-eddy simulations of a vehicle (also called an Ahmed body) moving under a freeway overpass at a distance of 0.75 w (width) from the bridge poles. Results include transient contours of mean velocity, turbulent kinetic energy, vorticity, and pressure around …


Big Lagoon Sea Level Rise, Kyra Cohen, Malia Seeley, Dustin Helliwell, Albert Wolff Oct 2022

Big Lagoon Sea Level Rise, Kyra Cohen, Malia Seeley, Dustin Helliwell, Albert Wolff

Student Projects

Cal Poly Humboldt Environmental Resources Engineering Senior Capstone.

The California Department of Transportation (Caltrans) is highly concerned sea level rise (SLR), due to climate change and the potential negative impacts on the California transportation system. SLR is especially important for routes constructed at low elevations and those immediately adjacent to the coast where SLR is one of the largest threats to the transportation system along the coast. Rising sea levels are expected to disrupt the daily lives of Californians, specifically the coastal economies, which increases the risk to public safety and contributes to the decline of ecosystems that are vital …


Sea Level Rise Analysis: High-Importance Access Road Protection, Max Alvin, Taylor Goodwyn, Karly Johnson, Pedro Valverde Oct 2022

Sea Level Rise Analysis: High-Importance Access Road Protection, Max Alvin, Taylor Goodwyn, Karly Johnson, Pedro Valverde

Student Projects

Cal Poly Humboldt Environmental Resources Engineering Senior Capstone.

This report provides an analysis of design alternatives and ultimately a preferred design to ensure the longevity of Highway 101 near Orick, CA which is under threat of sea level rise (SLR). Highway 101 is the main transportation corridor for communities stretching from Arcata to Crescent City, California. Caltrans provided an area of interest along Highway 101 just southwest of Orick, between mile markers 119.58 and 119.92. The project area of interest is illustrated below in Figure ES-1. This stretch of Highway 101 borders low lying pastures and Redwood Creek's historic estuary. …


Interaction Networks Are Driven By Community-Responsive Phenotypes In A Chitin-Degrading Consortium Of Soil Microbes, Ryan Mcclure, Yuliya Farris, Robert Danczak, William Nelson, Hyun-Seob Song, Aimee Kessell, Sneha Couvillion, Christopher Henry, Janet K. Jansson, Kristen S. Hofmockel Sep 2022

Interaction Networks Are Driven By Community-Responsive Phenotypes In A Chitin-Degrading Consortium Of Soil Microbes, Ryan Mcclure, Yuliya Farris, Robert Danczak, William Nelson, Hyun-Seob Song, Aimee Kessell, Sneha Couvillion, Christopher Henry, Janet K. Jansson, Kristen S. Hofmockel

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Soil microorganisms provide key ecological functions that often rely on metabolic interactions between individual populations of the soil microbiome. To better understand these interactions and community processes, we used chitin, a major carbon and nitrogen source in soil, as a test substrate to investigate microbial interactions during its decomposition. Chitin was applied to a model soil consortium that we developed, “model soil consortium-2” (MSC-2), consisting of eight members of diverse phyla and including both chitin degraders and nondegraders. A multiomics approach revealed how MSC-2 community-level processes during chitin decomposition differ from monocultures of the constituent species. Emergent properties of both …


Interaction Networks Are Driven By Community-Responsive Phenotypes In A Chitin-Degrading Consortium Of Soil Microbes, Ryan Mcclure, Yuuliya Farris, Robert Danczak, William Nelson, Hyun-Seob Song, Aimee Kessell, Joon-Yong Lee, Sneha Couvillion, Christopher Henry, Janet K. Jansson, Kristen S. Hofmockel Sep 2022

Interaction Networks Are Driven By Community-Responsive Phenotypes In A Chitin-Degrading Consortium Of Soil Microbes, Ryan Mcclure, Yuuliya Farris, Robert Danczak, William Nelson, Hyun-Seob Song, Aimee Kessell, Joon-Yong Lee, Sneha Couvillion, Christopher Henry, Janet K. Jansson, Kristen S. Hofmockel

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Soil microorganisms provide key ecological functions that often rely on metabolic interactions between individual populations of the soil microbiome. To better understand these interactions and community processes, we used chitin, a major carbon and nitrogen source in soil, as a test substrate to investigate microbial interactions during its decomposition. Chitin was applied to a model soil consortium that we developed, “model soil consortium-2” (MSC-2), consisting of eight members of diverse phyla and including both chitin degraders and nondegraders. A multiomics approach revealed how MSC-2 community-level processes during chitin decomposition differ from monocultures of the constituent species. Emergent properties of both …


Electrochemical Biosensing And Deep Learning-Based Approaches In The Diagnosis Of Covid-19: A Review, Omer Sadak, Ferhat Sadak, Ozal Yildirim, Nicole M. Iverson, Rizwan Qureshi, Muhammed Talo, Chui Ping Ooi, U. Rajendra Acharya, Sundaram Gunasekaran, Tanvir Alam Sep 2022

Electrochemical Biosensing And Deep Learning-Based Approaches In The Diagnosis Of Covid-19: A Review, Omer Sadak, Ferhat Sadak, Ozal Yildirim, Nicole M. Iverson, Rizwan Qureshi, Muhammed Talo, Chui Ping Ooi, U. Rajendra Acharya, Sundaram Gunasekaran, Tanvir Alam

Department of Agricultural and Biological Systems Engineering: Faculty Publications

COVID-19 caused by the transmission of SARS-CoV-2 virus taking a huge toll on global health and caused life-threatening medical complications and elevated mortality rates, especially among older adults and people with existing morbidity. Current evidence suggests that the virus spreads primarily through respiratory droplets emitted by infected persons when breathing, coughing, sneezing, or speaking. These droplets can reach another person through their mouth, nose, or eyes, resulting in infection. The "gold standard'' for clinical diagnosis of SARS-CoV-2 is the laboratory-based nucleic acid amplification test, which includes the reverse transcription-polymerase chain reaction (RT-PCR) test on nasopharyngeal swab samples. The main concerns …


Wastewater-Informed Public Health Intervention Playbook Sep 2022

Wastewater-Informed Public Health Intervention Playbook

Sustain Magazine

As the SARS-CoV-2 pandemic quickly spread from country to country and continent to continent in 2020, governments and scientists needed a way to track COVID-19 through populations in order to position public health interventions in the most impactful locations. Having a decision-based risk framework may help to guide policy creation that could minimize or prevent possible outbreaks and surges of infection within communities. The University of Louisville in partnership with Louisville’s Department of Public Health and Wellness tested this strategy in 2021 and 2022. This Wastewater-Informed Public Health Intervention Playbook describes the decisions and actions of that academic and public …


Design Of Solvent-Assisted Plastics Recycling: Integrated Economics And Environmental Impacts Analysis, Austin L. Lehr, Kayla L. Heider, Emmanuel A. Aboagye, John D. Chea, Jake P. Stengel, Pahola Thathiana Benavides, Kirti M. Yenkie Sep 2022

Design Of Solvent-Assisted Plastics Recycling: Integrated Economics And Environmental Impacts Analysis, Austin L. Lehr, Kayla L. Heider, Emmanuel A. Aboagye, John D. Chea, Jake P. Stengel, Pahola Thathiana Benavides, Kirti M. Yenkie

Henry M. Rowan College of Engineering Departmental Research

In 2018, the United States generated over 35. 7 million tons of plastic waste, with only 8.4% being recycled and the other 91.6% incinerated or disposed of in a landfill. The continued growth of the polymer market has raised concerns over the end of life of plastics. Currently, the waste management system is faced with issues of inefficient sorting methods and low-efficiency recycling methods when it comes to plastics recycling. Mechanical recycling is the commonest recycling method but presents a lower-valued recycled material due to the material incompatibilities introduced via the inefficient sorting methods. Chemical recycling offers a promising alternative …


Crop Response To Thermal Stress Without Yield Loss In Irrigated Maize And Soybean In Nebraska, Sandeep Bhatti, Derek M. Heeren, Steven R. Evett, Susan A. O'Shaughnessy, Daran Rudnick, Trenton E. Franz, Yufeng Ge, Christopher M.U. Neale Sep 2022

Crop Response To Thermal Stress Without Yield Loss In Irrigated Maize And Soybean In Nebraska, Sandeep Bhatti, Derek M. Heeren, Steven R. Evett, Susan A. O'Shaughnessy, Daran Rudnick, Trenton E. Franz, Yufeng Ge, Christopher M.U. Neale

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Thermal sensing provides rapid and accurate estimation of crop water stress through canopy temperature data. Canopy temperature is highly dependent on the transpiration rate of the leaves. It is usually assumed that any reduction in crop evapotranspiration (ET) leads to crop yield loss. As a result, an increase in canopy temperature due to a decrease in crop ET would indicate crop yield loss. This research evaluated the hypothesis that crop water stress could be detected using canopy temperature measurements (increased leaf temperature) from infrared thermometers (IRTs) before incurring crop yield loss. This would be possible in a narrow range when …


Real-Time Irrigation Scheduling Of Maize Using Degrees Above Non-Stressed (Dans) Index In Semi-Arid Environment, Hope Njuki Nakabuye, Daran Rudnick, Kendall C. Dejonge, Tsz Him Lo, Derek M. Heeren, Xin Qiao, Trenton E. Franz, Abia Katimbo, Jiaming Duan Sep 2022

Real-Time Irrigation Scheduling Of Maize Using Degrees Above Non-Stressed (Dans) Index In Semi-Arid Environment, Hope Njuki Nakabuye, Daran Rudnick, Kendall C. Dejonge, Tsz Him Lo, Derek M. Heeren, Xin Qiao, Trenton E. Franz, Abia Katimbo, Jiaming Duan

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Irrigation scheduling methods have been used to determine the timing and amount of water applied to crops. Scheduling techniques can include measurement of soil water content, quantification of crop water use, and monitoring of crop physiological response to water stress. The aim of this study was to evaluate the performance of a simplified crop canopy temperature measurement (CTM) method as Irrigation Principles. Soil and Water Conservation Engineera technique to schedule irrigation for maize. Specifically, the Degrees Above Non-Stressed (DANS) index, which suggests water stress when canopy temperature exceeds the non-stressed canopy temperature (Tcns), was determined by estimating T …


Modeling Actual Evapotranspiration With Msi-Sentinel Images And Machine Learning Algorithms, Robson Argolo Dos Santos, Everardo Chartuni Mantovani, Elpídio Inácio Fernandes-Filho, Roberto Filgueiras, Rodrigo Dal Sasso Lourenço, Vinícius Bof Bufon, Christopher M. U. Neale Sep 2022

Modeling Actual Evapotranspiration With Msi-Sentinel Images And Machine Learning Algorithms, Robson Argolo Dos Santos, Everardo Chartuni Mantovani, Elpídio Inácio Fernandes-Filho, Roberto Filgueiras, Rodrigo Dal Sasso Lourenço, Vinícius Bof Bufon, Christopher M. U. Neale

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The modernization of computational resources and application of artificial intelligence algorithms have led to advancements in studies regarding the evapotranspiration of crops by remote sensing. Therefore, this research proposed the application of machine learning algorithms to estimate the ETrF (Evapotranspiration Fraction) of sugar can crop using the METRIC (Mapping Evapotranspiration at High Resolution with Internalized Calibration) model with data from the Sentinel-2 satellites constellation. In order to achieve this goal, images from the MSI sensor (MultiSpectral Instrument) from the Sentinel-2 and the OLI (Operational Land Imager) and TIRS (Thermal Infrared Sensor) sensors from the Landsat-8 were acquired nearly …


Minimizing Surface Run-Off, Improving Underground Water Recharging, And On-Site Rain Harvesting In The Kathmandu Valley, Ambika P. Adhikari, Keshav Bhattarai Sep 2022

Minimizing Surface Run-Off, Improving Underground Water Recharging, And On-Site Rain Harvesting In The Kathmandu Valley, Ambika P. Adhikari, Keshav Bhattarai

Himalayan Research Papers Archive

Nepal's political institutions and administrative units were thoroughly restructured in 2015 with the promulgation of the new Constitution. Several rural areas were combined to meet the definition of urban threshold criteria to classify rural areas into urban categories. Accordingly, over 3,900 local political and administrative units were amalgamated into 753 units, of which, 293 units are classified as urban. Within these newly defined urban areas, many natural environments have been converted into impervious surfaces such as paved roads, sidewalks, and building roofs. These impervious surfaces have drastically increased the amount of surface run-offs-often termed as "urban floods"--under increasing precipitation caused …


Ag-Iot For Crop And Environment Monitoring: Past, Present, And Future, Nipuna Chamara, Md Didarul Islam, Geng Bai, Yeyin Shi, Yufeng Ge Sep 2022

Ag-Iot For Crop And Environment Monitoring: Past, Present, And Future, Nipuna Chamara, Md Didarul Islam, Geng Bai, Yeyin Shi, Yufeng Ge

Department of Agricultural and Biological Systems Engineering: Faculty Publications

CONTEXT: Automated monitoring of the soil-plant-atmospheric continuum at a high spatiotemporal resolution is a key to transform the labor-intensive, experience-based decision making to an automatic, data-driven approach in agricultural production. Growers could make better management decisions by leveraging the real-time field data while researchers could utilize these data to answer key scientific questions. Traditionally, data collection in agricultural fields, which largely relies on human labor, can only generate limited numbers of data points with low resolution and accuracy. During the last two decades, crop monitoring has drastically evolved with the advancement of modern sensing technologies. Most importantly, the introduction …


Climate And Genetic Data Enhancement Using Deep Learning Analytics To Improve Maize Yield Predictability, Parisa Sarzaeim, Francisco Muñoz-Arriola, Diego Jarquin Sep 2022

Climate And Genetic Data Enhancement Using Deep Learning Analytics To Improve Maize Yield Predictability, Parisa Sarzaeim, Francisco Muñoz-Arriola, Diego Jarquin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Despite efforts to collect genomics and phenomics (“omics”) and environmental data, spatiotemporal availability and access to digital resources still limit our ability to predict plants’ response to changes in climate. Our goal is to quantify the improvement in the predictability of maize yields by enhancing climate data. Large-scale experiments such as the Genomes to Fields (G2F) are an opportunity to provide access to “omics” and climate data. Here, the objectives are to: (i) improve the G2F “omics” and environmental database by reducing the gaps of climate data using deep neural networks; (ii) estimate the contribution of climate and genetic database …


Removing Soluble Phosphorus From Tertiary Municipal Wastewater Using Phosphorus- Deprived, Filamentous Microalgae, Aloysia Ahern Sep 2022

Removing Soluble Phosphorus From Tertiary Municipal Wastewater Using Phosphorus- Deprived, Filamentous Microalgae, Aloysia Ahern

Master's Theses

Harmful algal blooms (HABs) can be detrimental to ecosystems, human health, and economies. The low levels of phosphorus remaining in the effluent of municipal wastewater treatment plants can contribute to HAB formation. To achieve more complete phosphorus removal, an effluent treatment method has been proposed that uses phosphorus-deprived, filamentous microalgae to quickly assimilate soluble phosphorus to low concentrations. This study investigated two parameters that influence the feasibility of such a system: (1) the biomass growth productivity of algal cultures during the phosphorus deprivation period and (2) the correlation between the duration of this period and the phosphorus uptake rate by …


2022 Fall Engr333 Project Assignment, Matthew K. Heun Aug 2022

2022 Fall Engr333 Project Assignment, Matthew K. Heun

ENGR 333

The Fall 2022 ENGR333 project focused on sustainable heating for Calvin University.

I asked the students “What would it take to eliminate Calvin’s natural gas-related net CO2 emissions?”

Matt Kucinski (Calvin PR) wrote a story about the project. President Boer wrote a complementary post about the students’ work on LinkedIn.

Customer

The customer for this project was Dr. Wiebe Boer, President of Calvin University.


Formation Of Oil Particle Aggregates And The Impact On The Fate Of Oil, Wen Ji Aug 2022

Formation Of Oil Particle Aggregates And The Impact On The Fate Of Oil, Wen Ji

Dissertations

Spilled oil slicks are likely to break into droplets offshore due to wave energy. The fate and transport of such droplets are affected by suspended particles in local marine environment, through forming oil particle aggregates (OPAs). OPA formation is affected by various factors, including the properties of the particles and oil, the mixing energy and duration, etc. To investigate the impact of these factors, lab scale experiments are conducted by using seawater (both artificial and natural) and kaolinite and silica to simulate the formation of OPAs in baffled flasks. In the first experiment, 9 gm and 3 gm spherical silica …


Neonicotinoid Pesticide And Nitrate Mixture Removal And Persistence In Floating Treatment Wetlands, Julia K. Lindgren, Tiffany L. Messer, Daniel N. Miller, Daniel D. Snow, Thomas G. Franti Aug 2022

Neonicotinoid Pesticide And Nitrate Mixture Removal And Persistence In Floating Treatment Wetlands, Julia K. Lindgren, Tiffany L. Messer, Daniel N. Miller, Daniel D. Snow, Thomas G. Franti

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Mesocosm and microcosm experiments were conducted to explore the applicability of floating treatment wetlands (FTWs), an ecologically based management technology, to remove neonicotinoid insecticides and nitrate from surface water. The mesocosm experiment evaluated three treatments in triplicate over a 21-d period. Floating treatment wetland mesocosms completely removed nitrate-N over the course of the experiment even when neonicotinoid insecticides were present. At the completion of the experiment, 79.6% of imidacloprid and degradation byproducts and 68.3% of thiamethoxam and degradation byproducts were accounted for in the water column. Approximately 3% of imidacloprid and degradation byproducts and 5.0% of thiamethoxam and degradation byproducts …


Research On The Detection Technologies Of Ship Exhaust Gas In Emission Control Areas, Binting Tu Aug 2022

Research On The Detection Technologies Of Ship Exhaust Gas In Emission Control Areas, Binting Tu

World Maritime University Dissertations

No abstract provided.


Exploring The Roles Of Organic Matter Source And Transformation For Photochemical Characterization Of New York Lake Waters, Joseph Wasswa Aug 2022

Exploring The Roles Of Organic Matter Source And Transformation For Photochemical Characterization Of New York Lake Waters, Joseph Wasswa

Dissertations - ALL

Dissolved organic matter (DOM) is a critical component of aquatic systems that serves many purposes. Among them is the production of reactive intermediates (RIs) when irradiated with sunlight. Examples of RIs produced include the excited triplet states of dissolved organic matter (3DOM*), singlet oxygen (1O2), and hydroxyl radicals (•OH), all of which contribute to the degradation or inactivation of chemical or microbiological contaminants. It is therefore critical to understand how the sources and transformations of DOM may affect the production of RIs in sunlit aquatic systems.

The Adirondack Mountain region of New York, a historical hotspot for atmospheric sulfur and …


Optimising Existing Digital Workflow For Structural Engineering Organisations Through The Partnering Of Bim And Lean Processes, John Mclaughlin, Barry Mcauley Aug 2022

Optimising Existing Digital Workflow For Structural Engineering Organisations Through The Partnering Of Bim And Lean Processes, John Mclaughlin, Barry Mcauley

Conference Papers

Building Information Modelling (BIM) is now seen as one of the leading transformative processes within the Architectural, Engineering and Construction (AEC) sector and has the potential to assist in streamlining the structural design process. However, its practical implementation can often add another layer to the existing workflow and can result, to its detriment, in the primary objective of optimising structural workflows being hindered. This can lead to structural organisations producing 3D models in tandem with traditional drawings, a lack of human intervention regarding software interoperability, and a reluctance to move away from conventional work methods. This paper will explore how …


Using 2d Hec-Ras Modeling With Vertical Feature Extraction To Inform Ecological Design In The Lower Atchafalaya River Basin, Louisiana, Colin Anderson Aug 2022

Using 2d Hec-Ras Modeling With Vertical Feature Extraction To Inform Ecological Design In The Lower Atchafalaya River Basin, Louisiana, Colin Anderson

LSU Master's Theses

A 2D HEC-RAS model was created to demonstrate applications of hydraulic modeling for informing ecological design. This was done by comparing the hydrologic conditions of a baseline year (2010) to that of the environmental flow prescription from Kozak et al. (2016). The inundation results are relevant to hydraulic connectivity and cypress regeneration.

The hydraulic model was created by assimilating numerous data sources, refining the model with vertical feature (VF) extraction, and calibrating/validating the model. Several topo-bathymetric sources were combined to create the digital elevation model (DEM). Most importantly, this included bathymetry of the backswamp. Polylines of significant VFs in the …


Permafrost Landscape History Shapes Fluvial Chemistry, Ecosystem Carbon Balance, And Potential Trajectories Of Future Change, Scott Zolkos, Suzanne E. Tank, Steven V. Kokelj, Robert G. Striegl, Sarah Shakil, Carolina Voigt, Oliver Sonnentag, William L. Quinton, Edward A. G. Schuur, Donatella Zona, Peter M. Lafleur, Ryan C. Sullivan, Masahito Ueyama, David P. Billesbach, David Cook, Elyn R. Humphreys, Philip Marsh Aug 2022

Permafrost Landscape History Shapes Fluvial Chemistry, Ecosystem Carbon Balance, And Potential Trajectories Of Future Change, Scott Zolkos, Suzanne E. Tank, Steven V. Kokelj, Robert G. Striegl, Sarah Shakil, Carolina Voigt, Oliver Sonnentag, William L. Quinton, Edward A. G. Schuur, Donatella Zona, Peter M. Lafleur, Ryan C. Sullivan, Masahito Ueyama, David P. Billesbach, David Cook, Elyn R. Humphreys, Philip Marsh

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Intensifying permafrost thaw alters carbon cycling by mobilizing large amounts of terrestrial substrate into aquatic ecosystems. Yet, few studies have measured aquatic carbon fluxes and constrained drivers of ecosystem carbon balance across heterogeneous Arctic landscapes. Here, we characterized hydrochemical and landscape controls on fluvial carbon cycling, quantified fluvial carbon fluxes, and estimated fluvial contributions to ecosystem carbon balance across 33 watersheds in four ecoregions in the continuous permafrost zone of the western Canadian Arctic: unglaciated uplands, ice-rich moraine, and organic-rich lowlands and till plains. Major ions, stable isotopes, and carbon speciation and fluxes revealed patterns in carbon cycling across ecoregions …


Fate Of Metals In Presence Of Minerals And Mineral-Organic Assemblages, Neha Sharma Aug 2022

Fate Of Metals In Presence Of Minerals And Mineral-Organic Assemblages, Neha Sharma

McKelvey School of Engineering Graduate Student Theses & Dissertations

Metals can enter aquatic systems from natural and anthropogenic processes associated with weathering, sediment re-suspension, industrial activities, and atmospheric deposition. Metals pose health and environmental risks at high concentrations due to their potential toxicity and bioaccumulation, but many trace metals also serve as essential micronutrients for biogeochemical processes in natural aquatic systems. Biogeochemical processes such as methanogenesis, denitrification, and mercury methylation require transition metals such as nickel (Ni), cobalt (Co), copper (Cu), and molybdenum (Mo) for completion. These biogeochemical processes can be substantial contributors of greenhouse gases, such as methane (CH4) and nitrous oxide (N2O), into the atmosphere. The behavior, …


Advanced Nanomaterials And Module Designs For Efficient Photothermal Water Treatment, Deoukchen Ghim Aug 2022

Advanced Nanomaterials And Module Designs For Efficient Photothermal Water Treatment, Deoukchen Ghim

McKelvey School of Engineering Graduate Student Theses & Dissertations

Water scarcity is one of the most serious challenges that human beings face, and the demand for clean water will continuously increase as populations grow. Creating potable water from saline water is an important way to meet global freshwater demands. However, current desalination techniques require high energy consumption and a large scale to be efficient, restricting their utilization in remote and underdeveloped areas. These constraints motivate the development of sustainable water treatment methods that can be used with less energy input, in small modular configurations, and in off-grid water treatment systems. As an abundant and renewable energy source, sunlight has …


The Generation And Transport Of Charged Aerosols: Fundamental Study And Applications In Medicine And Energy Conversion, Hao Zhou Aug 2022

The Generation And Transport Of Charged Aerosols: Fundamental Study And Applications In Medicine And Energy Conversion, Hao Zhou

McKelvey School of Engineering Graduate Student Theses & Dissertations

Charged aerosols have significant implications in the field of functional material synthesis, pharmaceutical coating, and drug delivery. Electrospray systems are an effective methodology for generating highly charged monodispersed droplets in the size range from nanometer to micrometer. The prediction of surface charge, size and morphology of nanoparticles resulting from charged droplets are highly required for the precise control of nanoparticle properties and their effective utilization. However, the evolution of charged droplet is not well understood due to the existence of coulombic fission and ion evaporation processes. Thus, the goal of this dissertation is to elucidate how the precursor properties and …


Nanoscale Interfacial Control Of Ion Behaviors And Caco3 Formation In Environmental Systems, Yaguang Zhu Aug 2022

Nanoscale Interfacial Control Of Ion Behaviors And Caco3 Formation In Environmental Systems, Yaguang Zhu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Interfaces in environmental systems can change the distribution of pollutants and nutrients, determine the fate and transport of nanoparticles, and affect the efficiency of engineering projects. Complex interactions, including electrostatic interactions, Van der Waals interactions, chemical interactions, and ion-surface specific interactions, can all contribute to different ion, ion-pair, and nanoparticle formations near interfaces. Although environmental interfaces play critical roles, only a limited number of studies have considered the nanoscale picture of how they control ions and nanoparticles. Thus, this dissertation addresses three research questions: (1) How does sulfate chemically interact with calcium carbonate (CaCO3) during its heterogeneous formation on quartz …


Role Of Water Chemistry In Lead Release During Drinking Water Supply And Augmentation, Anushka Mishrra Aug 2022

Role Of Water Chemistry In Lead Release During Drinking Water Supply And Augmentation, Anushka Mishrra

McKelvey School of Engineering Graduate Student Theses & Dissertations

Lead is a toxic heavy metal and legacy contaminant in drinking water that can be released from lead service lines and lead-containing premise plumbing. Lead concentrations in water are sensitive to changes in water chemistry. The extent of lead release is often driven by the solubility of the corrosion products formed on the interior of the pipes. Therefore, it is critical to advance our understanding of the extent of lead released from different lead-based plumbing materials at equilibrium and the ability to control lead when it exceeds the regulatory levels. Lead measured in the 1st liter of water collected from …