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Title: CHARACTERIZATION OF DISPERSION AND ULTRAFINE PARTICLE EMISSION FACTORS USING NEAR ROADWAY FIELD MEASUREMENTS
Creator: Xiang, Sheng
Date: 2019
Description: Recent epidemiology evidence suggests that vehicle emissions are major contributors to poor urban air quality. Human exposure to elevated...
Show moreRecent epidemiology evidence suggests that vehicle emissions are major contributors to poor urban air quality. Human exposure to elevated concentration of traffic emissions has been associated with increased risk factors for a range of negative health outcomes. Evaluation of human exposure to vehicle emissions (e.g. ultrafine particles) mainly relies on dispersion models. Consequently, dispersion models need to comply with constantly increasing requirements to provide predictions of pollutant concentration. The dynamic of near roadway dispersion process needs to be investigated since most of the existing models does not account traffic condition variability (e.g. vehicle type and mode of operation) for dispersion. A five-year long field study was conducted to characterize dispersion near roadway with various vehicle mode of operation and vehicle type. To better understand the dispersion process near roadway, the impact of different ambient background categories (e.g. remote, lake, urban, industrial) on ultrafine particles (UFPs) need to be evaluated. Results demonstrate that each category has a different average ambient background concentration (pt cm–3) as follows: remote, 2,700; lake, 6,000; industrial 12,000 and urban 11,000. The large variations exist in ambient background concentration will result in significant variations in near roadway concentrations. The total near roadway measurements are generally near 20,000 pt cm–3 and reach to 60,000 pt cm–3 depending on the background and traffic emission. The dispersion near the roadway is also investigated in this study. A roadway restricted to light-duty vehicles (LDVs) was selected to conducted near roadway field measurement. Results indicate that the dispersion induced by vehicles is a two-stage process. When under the unsteady-state condition with small number of operating vehicles, the rate of dispersion near roadway increased from 2 m2 s-1 to 6 m2 s-1 as the number of vehicles increased. For steady-state condition, the rate of dispersion was constant near 6 m2 s-1 and not increased with additional vehicles. For a roadway mixed with both LDVs and heavy duty vehicles (HDVs), similar results were found. Dispersion increased from 6 to 18 m2 s-1 as total vehicle flow rate increased to 10,000 veh h-1 and HDV flow rate increased to 1000 veh h-1. Finally, the calculated dispersion near roadway is used to estimate the UFP emission factors. The UFP emission factors were ranged from 0.5 × 1013 to 1.5 × 1013 pt km-1 veh-1 and from 7 × 1014 to 20 × 1014 pt km-1 veh-1 for LDVs and HDVs, respectively. The variations in UFP emission factors are due to change in vehicle mode of operation.The results from this study will be critical for parameterization of dispersion near roadway and provide important emission inventory for interdisciplinary partnership among different fields (e.g. air quality, transportation design and urban planning) in solving transportation air quality problem.
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Title: Improving Methods to Measure the Transport of Outdoor Pollutants into Residential Indoor Environments
Creator: Zhao, Haoran
Date: 2019
Description: Human exposure to ambient pollutants such as particulate matter, ozone, and oxides of nitrogen are associated with a variety of adverse health...
Show moreHuman exposure to ambient pollutants such as particulate matter, ozone, and oxides of nitrogen are associated with a variety of adverse health effects in epidemiology studies. However, much of human exposure to outdoor pollutants occurs inside residential buildings where people spend the majority of their time. One important determinant of indoor exposures to pollutants of outdoor origin is the “penetration factor” of the building envelope, which characterizes the ability of the building enclosure assembly to filter outdoor air as it infiltrates indoors. To date, measurements of envelope penetration factors for various outdoor pollutants in real indoor environments remain extremely limited, in part because current methods suffer from high costs, high uncertainty, and high levels of invasiveness presented to building occupants. Therefore, the research objectives in this dissertation aims to (1) develop and/or refine (as applicable) methods to measure the penetration of outdoor particulate matter, ozone, and nitrogen oxides in buildings and (2) apply them to characterize a diverse sample of residential buildings in Chicago, IL, including single-family homes, multi-family homes, and homes before and after they undergo energy efficiency retrofits. Results from this research will provide refined methods that others can use in field measurements and novel data for modelers to better assess indoor exposures to outdoor pollutants, which can then be used to improve exposure assessments for epidemiology studies.
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Title: ESTIMATES OF FINE AND ULTRAFINE PARTICLE REMOVAL EFFICIENCY FOR RESIDENTIAL HVAC FILTERS USING IN-SITU SIZE-RESOLVED EFFICIENCY MEASUREMENTS
Creator: Zeng, Yicheng
Date: 2018
Description: Central heating, ventilating, and air-conditioning (HVAC) filters are commonly evaluated for their size-resolved particle removal efficiency ...
Show moreCentral heating, ventilating, and air-conditioning (HVAC) filters are commonly evaluated for their size-resolved particle removal efficiency (for particles 0.3 to 10 µm in diameter) by challenging them with a test aerosol in a laboratory setting. However, aerosol measurement and reporting classifications that are most commonly used in regulatory monitoring and building measurements include integral measures of mass-based concentrations (e.g., PM2.5, or the mass concentration of particles smaller than 2.5 µm) or total number concentrations (e.g., total UFPs, or ultrafine particles smaller than 100 nm). Because filter test standards have not traditionally considered these measures, building owners, occupants, and other key personnel cannot make informed decisions on HVAC filtration for these classifications. Moreover, because the removal efficiency for integral measures of total mass and number concentrations are also a function of the underlying particle size distributions that challenge the filter, one must consider the varied sources and size distributions of aerosols that filters encounter in real building applications. This work has two objectives: (1) to measure the in-situ size-resolved particle removal efficiency of a large number of commercially available residential HVAC filters, and (2) to use those size-resolved efficiency data to estimate integral measures of PM2.5 and total UFP removal efficiency for the same filters for typical residential indoor settings based on a literature survey of measured indoor particle size distributions. Particle concentration measurements were made upstream and downstream of a wide range of commercially available filters installed in a central air handling unit in an unoccupied residential apartment unit. A literature review was conducted to gather a variety of indoor particle size distributions (PSDs) from across the world and tri-modal lognormal distributions were fit to each of them. Finally, the particle removal efficiency for each filter for integral measures of indoor UFPs and PM2.5 were calculated for each indoor PSD. In-situ size-resolved measurements indicate that filters with similar rating values but from different manufacturers can have very different removal efficiencies for integral measures of PM2.5 and total UFPs, and that the assumption for indoor PSDs can greatly impact estimates of removal efficiency.
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Title: Parameterization of vertical dispersion coefficient (σz) near roadway: vehicle wake, density and types
Creator: Yu, Yu-Ting
Date: 2020
Description: Pollutants emitted by motor vehicles is one of the major public concern in modern society since pollutants (e.g. ultrafine particles and CO2)...
Show morePollutants emitted by motor vehicles is one of the major public concern in modern society since pollutants (e.g. ultrafine particles and CO2) have been related to adverse health effect and climate change. Currently, air quality dispersion models (e.g. CALINE4 and AERMOD) are widely used to predict concentration near roadway. However, both air quality dispersion models are not account for the vehicle variability (vehicle types), causing the inaccuracy in predicting pollutant concentration near roadway. To better understand the dynamic of dispersive process, it is important to evaluate the variation of vertical dispersion coefficient (σz) for different vehicle types (e.g. LDV and HDV). A “wake area model” is developed based on “effective wake area” and vehicle density to reveal the dynamic of dispersion process that related to vehicles. Results from this thesis demonstrate that the near roadway σz that calculated from field measurements increases as vehicle density increases and HDV can generate higher value of σz compare to LDV. σz increase from 1.7 m to 4 m with LDV density increase from 0.005 m-1 to 0.18 m-1; while σz starts at 2 m and reach up to 6 m with HDV density increase from 0.001 m-1 to 0.01 m-1. The significant differences of σz are due to vehicle density and vehicle types. The effective wake area contributed by one HDV (397 m2) is much larger than effective wake area contributed by one LDV (13 m2), which indicates that one HDV contributes 31 times higher than one LDV in terms of near roadway σz. The significant differences of “effective wake area” are due to vehicle wake structure and vehicle dimension.Compared to the air quality dispersion models results, both CALINE4 and AERMOD failed to respond the variation of σz as vehicle density increases for LDVs and HDVs. CALINE4 shows the value of σz is near 2.8 m and 2.4 m for LDV and for vehicle fleet (mixture of LDV and HDV), respectively. AERMOD shows the value of σz is near 1.2 m and 1.3 m for LDV and for vehicle fleet, respectively. Because both air quality dispersion models did not correctly predict σz near roadway, a new equation that parameterize σz near roadway need to be developed to better predict the σz in real world condition. For a given road segment, the parameterization of σz is a result from dimension of “effective wake area” for different vehicle types and number of “effective wake area” for a vehicle fleet. Comparison of measured and parameterized σz near roadway dispersion coefficients show good agreement (slope=0.99, R2=0.85) with a range between 1 and 4 m for LDVs and 2 to 6 m for HDVs. Also, Comparison of measured and simulated CO2 show good agreement (slope=1, R2=0.90) with a range between 0.01 g m-3 to 0.12 g m-3 for simulated value and 0.01 g m-3 to 0.14 g m-3 for measured value. For UFPs, the results also show good agreement (slope=1.14, R2=0.71) with a range between 600 pt cm-3 to 11,000 pt cm-3 for simulated value and 600 pt cm-3 to 17,000 pt cm-3 for measured value.The “wake area model” provides a new perspective for σz that related to vehicles and bridges vehicle wake to σz. The results from this study will be critical for improving predictions of pollutant concentration from air quality dispersion near roadway.
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Title: UTILITY OF WATERSHED MODELS: IMPROVING TMDL DEVELOPMENT THROUGH A MARGIN OF SAFETY ESTIMATION AND UNCERTAINTY COMMUNICATION
Creator: Nunoo, Robert
Date: 2020
Description: Watershed models are used to represent the physical, chemical, and biological mechanisms that determine the fate and transport of pollutants...
Show moreWatershed models are used to represent the physical, chemical, and biological mechanisms that determine the fate and transport of pollutants in waterbodies (Daniel 2011). These models, in general, are used for exploratory, planning, and regulatory purposes (Harmel et al. 2014). Watershed models have numerous applications; one such use is the development of total maximum daily load (TMDL). TMDL is the amount of pollution a waterbody can receive without becoming impaired. Because of the challenge of uncertainty associated with models and the TMDL development process, the United States Clean Water Act Section 303 (d)(1)(c) requires that a margin of safety (MOS) be specified to account for uncertainty in TMDLs. The question of how MOS is estimated in TMDL was identified as a problem by the National Research Council (NRC 2001). Since the identification of the problem about two decades ago, there have been very few inventories or audits of approved TMDL studies. This study describes a natural language processing and machine learning aided review of the MOS in approved TMDLs from 2002 to 2016. The study determined whether the MOS values incorporated followed a pattern and examined whether there exist a relationship between MOS values and some ecological conditions. Relatively few TMDLs were based on some form of calculation to estimate explicit MOS values; these TMDLs constituted only 16% of the reviewed sample. The remaining 84% used conventional values, but few of those studies provided reasons for their selected values. A statistical assessment of those MOS values revealed that the MOS depended on States (location of waterbody), USEPA regions, waterbody type, designated water use, TMDL model used, and dataavailability. The findings indicate that few TMDL developers are following the National Research Council’s suggestions of using a rigorous uncertainty estimation approach for rational choices for the MOS. An adaptive approach based on Bayes-Discrepancy was proposed for estimating an MOS for a TMDL. The approach is based on the Bayesian hierarchical framework of estimating uncertainty associated with watershed models. With this approach, TMDL developers can communicate the effects of their watershed model. The approach was applied to a Ferson Creek model of the Fox River watershed to access variability and uncertainty in the model results, and also estimate possible MOS values for two monitoring stations in the watershed. Results suggest that an MOS of 0.04 mg/L could lead to a 0.1 probability of violating the water quality standard for an underpredicting model. The Bayes-discrepancy estimation method will enable TMDL developers and watershed managers to strike a balance between implementation options and water quality concerns.
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Title: IMPROVING KNOWLEDGE OF MICROBIAL DYNAMICS ON BUILDING MATERIALS UNDER HIGH MOISTURE CONDITIONS
Creator: ZHAO, DAN
Date: 2020
Description: Most buildings experience some kind of high moisture event(s) throughout their life cycles, often resulting from water leaks or migration of...
Show moreMost buildings experience some kind of high moisture event(s) throughout their life cycles, often resulting from water leaks or migration of water vapor through the enclosure. Dampness and moisture in buildings leads to fungal growth and is associated with adverse human health outcomes. Although the dynamics of fungal growth on buildings materials has been investigated for decades, few studies have integrated modern chemical or microbiological analytical methods (e.g., DNA sequencing, qPCR, etc.) to understand microbial dynamics on materials held at high humidity conditions. Moreover, most mold growth prediction models remain relatively simplistic and rely solely on empirical data for visible mold growth. To bridge some of these gaps, this research aims to improve understanding of microbial growth and community dynamics on building materials under high moisture conditions and to improve our ability to predict microbial growth and community dynamics under a variety of conditions. Five distinct but overlapping research objectives are used to achieve these goals, including: (1) evaluating the growth of microorganisms on wetted building materials and identifying relationships between specific microbial taxa, metabolites, and environmental variables; (2) identifying inherent material chemistry drivers of fungal growth susceptibility and their relation to microbial community structure; (3) exploring how fluctuating moisture exposures impact bacterial and fungal growth and dynamics on building materials; (4) investigating microbial interactions using isolated communities on a single material; and (5) evaluating and improving existing mathematical mold growth models.
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Title: Impact of powder heterogeneity on particle collection behaviors in a cylindrical electrostatic precipitator
Creator: Lee, Eric Monsu
Date: 2019
Description: Injection of powdered activated carbon (PAC) upstream of electrostatic precipitators (ESPs) has been the most commonly used strategy for post...
Show moreInjection of powdered activated carbon (PAC) upstream of electrostatic precipitators (ESPs) has been the most commonly used strategy for post-combustion mercury emissions control at coal-fired power plants. However, as PAC injection rate increases, the darkening filters with particulate matter (PM) samples collected downstream of ESPs indicates an unidentified performance anomaly. It has been hypothesized that injection of PAC can introduce unexpected heterogeneity to the PM collection process in ESPs as PAC differs greatly from fly ash in both physical and electrical properties and can potentially pose challenges to ESPs that were initially operated for coal fly ash removal. The present study is carried out by an experimental study and a numerical study. The experimental study centers on the differential collection of PAC-fly ash admixtures and shows increasing trends of unaccounted-for particles as PAC concentration increases in the admixtures. In addition, measurement of powder resistivity of the ESP-collected powder samples infers that the unaccounted-for particles become more PAC-concentrated as PAC concentration becomes higher in the admixtures. The numerical study aims to extract additional variable(s) leading to higher percentage of unaccounted-for particles by using COMSOL Multiphysics. The Euler-Lagrange numerical scheme enables the modeling of the cylindrical ESP used during the experimental study and allows for solving the interrelated physics, including electric field coupled with charge conservation, electro-hydro-dynamics (EHD) fluid velocity field, and particle tracing. The model shows that the induced EHD vortex flow field due to the inhomogeneous current density along the collection electrode can result in continue entrainment of sub-micrometer particles of both fly ash and PAC. The experimental and numerical results provide new understanding for explaining the increasingly darkening PM filters as PAC injection rate increases.
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Title: The Effect of Time Step on HSPF Model Performance
Creator: Rubinstein, Benjamin J.
Date: 2023
Description: Hydrological modeling is a mature and well researched field; however, because most climate data are collected on hour or greater time...
Show moreHydrological modeling is a mature and well researched field; however, because most climate data are collected on hour or greater time intervals there is very little research on the effect of using high resolution data as inputs for the models. A Python tool for downloading high resolution five minute interval data from the Oklahoma Mesonet was created and the PyHSPF Python package was used to generate, calibrate, and validate HSPF models using five minute, one hour, and daily time steps. Flow errors, R², and Nash-Sutcliffe efficiency for simulated outflows, and resource usage were compared for each model. The hourly and five minute models performed similarly well, and the daily model performed significantly worse. The results of this work could prove useful for policy makers and researchers looking to update or create new climate data collection protocols, and the tools used can be applied to many different kinds of future research.
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Title: ESTIMATES OF AIR EXCHANGE RATES THROUGH THE USE OF TOTAL VOLATILE ORGANIC COMPOUND DECAY MEASUREMENTS
Creator: Bradley, Christopher
Date: 2021
Description: Indoor air exchange rates are commonly used to assess the overall fitness of a building and assess its performance. More recently, air...
Show moreIndoor air exchange rates are commonly used to assess the overall fitness of a building and assess its performance. More recently, air exchange has become a concern due to the COVD-19 pandemic, requiring replacement air to ensure safety; especially so considering that humans spend much of their time indoors. Building science has focused on air exchange to quantify needs for thermal loads, balancing the overall tightness of a building with the amount of energy consumed. Moreover, guidelines have been created by several different organizations to maintain adequate ventilation to remove indoor air pollution, replacing it with clean outdoor air. Research focuses on how to maintain a comfortable and safe quality of indoor air while balancing the needs of the energy crisis.When installed with proper HVAC systems, air exchange rates can be set to a recommended value based upon the conditions of the environment. Buildings without mechanical ventilation face another issue, mainly that they only rely on natural ventilation and the infiltration rate. Temperature differences between the indoor and outdoor environment and the condition of wind speed and direction create pressure differences across the building envelope, influencing the infiltration rate, which can change the amount of air exchange in buildings with natural or mechanical ventilation. Currently, air exchange rates are commonly measured using tracer gases. More frequently used gases have included perfluorocarbon, sulfur hexafluoride, and carbon dioxide, though none of these have proven to be ideal tracers. Alongside this, cost and burden on the participants of these studies often limit the amount of measurements made. Numerous studies have been conducted on how to model the air exchange rate by the changes in concentrations, but accuracy depends on the amount of information available. Other attempts have been made to characterize buildings by their infiltration rate to make estimations, but other questions have arisen about the accuracy of these methods. Due to their ubiquity in indoor environments, volatile organic compounds have been suggested as a plausible tracer gas for measuring air exchange rates. The plausibility of this method raises questions, such as their behavior within the indoor environment, their ability to be measured and the cost to measure concentrations, and the analytical requirements to characterize the rates of removal as air exchange rates. However, due to the rapid increase of available technology in low cost, lightweight, high-resolution sensors, this novel method of using VOCs, especially indicators of total VOCs (TVOCs), may prove fruitful in measuring air exchange within specific microenvironments. Analysis of time-series TVOC concentration measurements taken from a study conducted in multiple residences was conducted to investigate the feasibility of using these measurements, and especially naturally occurring elevation and decay periods, as a proxy for calculating air exchange rates. Though the removal rates of these compounds fell within the range of typical air exchange rates for residential spaces, the results of this analysis suggest the method has potential but with limitations, including the unknown behavior of the individual compounds comprising TVOC measurements within the space, proximity and mixing effects, and potentially invalid comparisons to air exchange rates given from a LBLX model rather than simultaneous tracer gas tests. Future work should explore simultaneous use of TVOC measurements alongside conventional tracer gas testing to further explore the potential utility of such methods.
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Title: PER – AND POLYFLUOROALKYL SUBSTANCES FATE AND TRANSPORT IN SEDIMENTS, SAND, AND ADSORBENT MEDIA
Creator: Manwatkar, Prashik
Date: 2022
Description: Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are two important organic chemicals of the per- and polyfuoroalkyl...
Show morePerfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are two important organic chemicals of the per- and polyfuoroalkyl substances (PFAS) group that have contaminated land, water, and the air since 1950. The continuous release of PFAS from the surface of land into water is not easy to forecast and an appropriate treatment method needs to be economically viable since there are currently around 42,000 suspect industrial and municipal sites in the United States. For a true reproduction of real-world pollution patterns, we constructed polypropylene tanks, performed laboratory-based experiments, and analyzed the samples using EPA method 533. In this study, we examined the fate and transport of long- and short-chain PFAS, including PFOA, PFOS, and perfluorobutanesulfonic acid (PFBS), from sediments, adsorbent media, and sands under overlaying water tanks. Granular activated carbon (GAC), biochar (BC), and Fluorosorb® (FS) were also added between the contaminated sediments and the sand layer in order to observe capping effectiveness. As one of the best ways to treat contaminated sediments on a large scale, adsorbent beds may reduce contaminants migration and support the degradation of contaminants. We found that all three chemicals were able to pass through the adsorbent layers of 3-4 inches from 4-5 inches of contaminated sediments and reach the top surface of the beds (25-30 inches). In the top 5-7 inches, PFBS concentration varied from 0.28 ppb to 0.78 ppb for all adsorbent tanks for 7 days. Whereas the bottom contaminated sediments concentrations of PFBS were 8518 ppb to 9481 ppb. We also observed the concentrations at top ports increased by 0.59 ppb to 2.31 ppb in 21 days, and ultimately, 0.58 ppb to 7.07 ppb in 69 days. While PFOA and PFOS found different metabolites in all layers, they provided noticeably lesser concentrations in contaminated sediments compared to PFBS. Further, the results of this study can be useful for validating the contaminant transport model predictions by identifying linear or nonlinear sorption equilibrium processes and diffusion-dispersion processes in sediment, sand, and various adsorbent media.
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Title: WASTEWATER COLLECTION SYSTEM MODELING: TOWARDS AN INTEGRATED URBAN WATER AND ENERGY NETWORK
Creator: Wang, Xiaolong
Date: 2020
Description: Wastewater collection systems, among the oldest features of urban infrastructure, are typically dedicated to collect and transport wastewater...
Show moreWastewater collection systems, among the oldest features of urban infrastructure, are typically dedicated to collect and transport wastewater from users to water resource recovery facilities (WRRFs). Since the 1970s, wastewater engineers and scientists have come to understand that wastewater collection systems can bring benefits for urban water and energy networks, including thermal energy recovery and converting pipelines to bioreactors. However, there is little knowledge about the temporal and spatial changes of collection systems parameters that are important for these applications. Furthermore, the vast majority of existing studies of these applications have focused on laboratory or extremely small-scale systems; there have been few studies about beneficial applications associated with large-scale systems. The purpose of this study is to increase our understanding of how urban wastewater collection systems can bring potential benefits to urban water and energy systems. Models describing wastewater hydraulics, temperature, and water quality can provide valuable information to help evaluate thermal energy recovery and wastewater pretreatment feasibility. These kinds of models, and supporting data from a case study, were used in this study; sizes of the theoretical wastewater collection systems range from 2.6 L/s to 52 L/s, and the sample locations of the case study had flows ranging from 2.3 L/s to 24.5 L/s. A cost-benefit analysis of wastewater source heat pumps was used to evaluate the thermal energy recovery feasibility for different sizes of wastewater collection systems. Results show that the large collection system can support a large capacity heat pump system with a relatively low unit initial cost. Small collection systems have a slightly lower unit operating cost due to the relatively high wastewater temperature. When the heat pump system capacity design was based on the average available energy from the collection system, larger systems have lower payback times; the lowest payback time is about 3.5 years. The wastewater quality model was used to describe the dissolved oxygen (DO) and organic matter concentrations changes in the collection system. The model provides a framework for predicting pretreatment capability. Model results show that DO concentration is the limiting parameter for organic matter removal. Larger collection systems can provide more organic matter removal because they provide relatively longer retention times, and they offer the potential for greater DO reaeration. The model can also be used to identify environmental conditions in sewer pipelines, providing information for potential issues predication.
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Title: High-latitude plasma drift structuring from a first principles ionospheric model
Creator: Kim, Heejin
Date: 2020
Description: In the high-latitude ionosphere dense plasma formations called polar cap patches are sometimes observed. These patches are often associated...
Show moreIn the high-latitude ionosphere dense plasma formations called polar cap patches are sometimes observed. These patches are often associated with ionospheric scintillation, a rapid fluctuation in the amplitude and phase of a radio signal that degrades communications and navigation systems. Predicting polar cap patch movement across the polar cap is an important subject for enabling forecasting of the scintillation.Lagrangian coherent structures (LCSs) are ridges indicating regions of maximum fluid separation in a time-varying flow. In previous studies, the Ionosphere-Thermosphere Algorithm for Lagrangian Coherent Structures (ITALCS) predicted the location of LCSs. These LCSs were shown to constrain polar cap patch source and transport regions for flow assumed to due to $\vec{E} \times \vec{B}$ plasma drift. The LCSs were predicted based on an empirical model of the high-latitude electric field for $\vec{E}$. In this thesis, the LCSs are generated using the first principles ionospheric model SAMI3 (SAMI3 is Another Model of the Ionosphere) as the model for electric field. The work relies on an understanding of various magnetic coordinate systems in space science, and includes three different approaches for attempting to generate the $\vec{E} \times \vec{B}$ drift as the flow fields that are to input to ITALCS. Finally, a representative LCS result is obtained with SAMI3 and shown to be at the high latitudes on the dayside, similar to prior work, but spanning a shorter longitudinal range.
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Title: Characterization of turbulent mixing near roadways based on measurements of short-term turbulence kinetic energy and traffic conditions
Creator: Hu, Zhice
Date: 2020
Description: Turbulence determines how vehicle emissions mix with the surrounding air and determine the distribution of pollutants on the roadway and...
Show moreTurbulence determines how vehicle emissions mix with the surrounding air and determine the distribution of pollutants on the roadway and downwind. 600 5-min near roadway simultaneous measurements (2016 to 2018) of turbulent kinetic energy (TKE), meteorological conditions, and traffic information (vehicle flow rate, density, and traffic mix (LDVs & HDVs) were used to characterize TKE. Short-term measurements (5 min.) were required to characterize the large variation in traffic flow rate that occurred in short time periods. Two roadways (Lakeshore Drive (LSD), Dan Ryan Expressway (DRE)) with distinctly different traffic composition (HDV%) and road configurations were selected for monitoring. Results indicate that variations in near-road wind speed (0.5 to 3.5 m s-1) had only a slight influence on TKE measurements. Background contributed 40% of the total measured TKE. The average dissipation rate traffic-induced TKE from on-road to near-road measurement was 90%. The average near roadway TKE (background subtracted) was 0.6 (m2 s-2) (0.2 st. dev) for LDVs only, and 0.8 (m2 s-2) (0.3 st. dev) for mixed fleet traffic flow (HDV averaged 8.4%). The increase in TKE was related to the increase in the HDV flow rate for free-flow traffic conditions but not for congestion conditions. TKE generated by individual HDVs was significantly higher than TKE generated from individual LDVs for free-flow traffic conditions. HDVs represent only a small fraction of the vehicle fleet mix (typical 1 to 10%) so that the overall effect of HDVs in changing vehicle fleet is difficult to quantify. However, the single HDV can induce near 11 times TKE than a single LDV in free-flow condition, which can validate the significant variation in the ensemble mean traffic-induced TKE under the same traffic fleet flow that is due to HDVs.
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Title: DEVELOPMENT AND APPLICATION OF A NATIONALLY REPRESENTATIVE MODEL SET TO PREDICT THE IMPACTS OF CLIMATE CHANGE ON ENERGY CONSUMPTION AND INDOOR AIR QUALITY (IAQ) IN U.S. RESIDENCES
Creator: Fazli, Torkan
Date: 2020
Description: Americans spend most of their time inside residences where they are exposed to a number of pollutants of both indoor and outdoor origin....
Show moreAmericans spend most of their time inside residences where they are exposed to a number of pollutants of both indoor and outdoor origin. Residential buildings also account for over 20% of total primary energy consumption in the U.S. and a similar proportion of greenhouse gas emissions. Moreover, climate change is expected to affect building energy use and indoor air quality (IAQ) through both building design (i.e., via our societal responses to climate change) and building operation (i.e., via changing meteorological and ambient air quality conditions). The overarching objectives of this work are to develop a set of combined building energy and indoor air mass balance models that are generally representative of both the current (i.e., ~2010s) and future (i.e., ~2050s) U.S. residential building stock and to apply them using both current and future climate scenarios to estimate the impacts of climate change and climate change policies on building energy use, IAQ, and the prevalence of chronic health hazards in U.S. homes. The developed model set includes over 4000 individual building models with detailed characteristics of both building operation and indoor pollutant physics/chemistry, and is linked to a disability-adjusted life years (DALYs) approach for estimating chronic health outcomes associated with indoor pollutant exposure. The future building stock model incorporates a combination of predicted changes in future meteorological conditions, ambient air quality, the U.S. housing stock, and population demographics. Using the model set, we estimate the total site and source energy consumption for space conditioning in U.S. residences is predicted to decrease by ~37% and ~20% by mid-century (~2050s) compared to 2012, respectively, driven by decreases in heating energy use across the building stock that are larger than coincident increases in cooling energy use in warmer climates. Indoor concentrations of most pollutants of ambient origin are expected to decrease, driven by predicted reductions in ambient concentrations due to tighter emissions controls, with one notable exception of ozone, which is expected to increase in future climate scenarios. This work provides the first known estimates of the potential magnitude of impacts of expected climate changes on building energy use, IAQ, and the prevalence of chronic health hazards in U.S. homes.
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Title: Using High-Pressure Reverse Osmosis Technique to Desalinate Produced Water
Creator: Dallalzadeh Atoufi, Hossein
Date: 2023
Description: This dissertation presents a comprehensive investigation into the use of high-pressure reverse osmosis (HPRO) to desalinate produced water (PW...
Show moreThis dissertation presents a comprehensive investigation into the use of high-pressure reverse osmosis (HPRO) to desalinate produced water (PW) in the oil and gas industry, with the aim of developing sustainable water management strategies. The study analyzes fouling mechanisms in HPRO desalination, revealing the applicability of Hermia's fouling mechanism to high-salinity waters and highlighting the negligible impact of complete pore blocking and standard pore blocking in crossflow reverse osmosis (RO) desalination. Furthermore, the research investigates ion transport through commercial polyamide thin film composite membranes using the solution-friction model, elucidating the influence of factors such as pressure, temperature, and crossflow velocity on the initial flux while minimal impact on steady-state flux is observed. The assessment of oil and gas waste discharge in water systems provides insights into potential environmental consequences, and the analysis of the behavior of per- and polyfluoroalkyl substances (PFAS) in contaminated sediments using passive sampling demonstrates the rapid uptake of shorter-chain PFAS compounds due to their lower sorption potential and faster diffusion rates. The dissertation contributes to the development of sustainable water management strategies, addressing the challenges of produced water treatment and environmental contamination in the oil and gas industry, and offers valuable information on fouling mechanisms, impacts of ion transport mechanisms, waste discharge and PFAS behavior, enabling optimized desalination processes, informed waste management practices, and a better understanding of environmental contamination issues.
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