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Impact Of Chain Architecture On The Thickness Dependence Of Physical Aging Rate Of Thin Polystyrene Films, Gregory Brown, Elizabeth Lewis, Bryan D. Vogt 2020 University of Akron

Impact Of Chain Architecture On The Thickness Dependence Of Physical Aging Rate Of Thin Polystyrene Films, Gregory Brown, Elizabeth Lewis, Bryan D. Vogt

Williams Honors College, Honors Research Projects

The dynamics of polymer thin films have been demonstrated to be significantly altered from the bulk, but the origins of such differences are not well defined. In this work, we seek to understand the differences in the structural dynamics (or physical aging) of polystyrene (PS) through branching and other well defined architectures (comb and centipede). The aging dynamics of ultrathin films (< 30 nm) differ from relatively thick films (100-150nm) with linear PS thin films aging more rapidly than the relatively “bulk-like” thick films. Ellipsometric measurements are used to characterize the physical aging rate of the films. The change in film thickness and refractive index as the films are held below the glass transition temperature (Tg) provides a simple measure of the physical aging. In this study, four different architectures (linear, comb, 4 arm star, and centipede) will be investigated. For each PS architecture, the aging rate will be determined for film thickness ranging ...


Multidisciplinary Education And Research In Biomathematics For Solving Global Challenges, Padmanabhan Seshaiyer 2019 Illinois State University

Multidisciplinary Education And Research In Biomathematics For Solving Global Challenges, Padmanabhan Seshaiyer

Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.


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Keto Fast Diet Reviews Pills, Cost & Ingredient, Keto Fast Diet Diet 2019 University of California, San Francisco

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Keto Fast Diet Diet

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A Review Of Pesticide Fate And Transport Simulation At Watershed Level Using Swat: Current Status And Research Concerns, Ruoyu Wang 2019 University of California, Davis

A Review Of Pesticide Fate And Transport Simulation At Watershed Level Using Swat: Current Status And Research Concerns, Ruoyu Wang

Ruoyu Wang

The application of pesticides in agriculture is a widely-used way to alleviate pest stresses. However, it also introduces various environmental concerns due to the offsite movement of pesticide residues towards receiving water bodies. While the application of process-based modeling approaches can provide quantitative information on pesticide exposure, there are nonetheless growing requirements for model development and improvement to better represent various hydrological and physico-chemical conditions at watershed scale, and for better model integration to address environmental, ecological and economic concerns. The Soil and Water Assessment Tool (SWAT) is an ecohydrological model used in over 3,000 published studies, including about ...


Environmental Fate And Impact Assessment Of Thiobencarb Application In California Rice Fields Using Ricewq, Ruoyu Wang 2019 University of California, Davis

Environmental Fate And Impact Assessment Of Thiobencarb Application In California Rice Fields Using Ricewq, Ruoyu Wang

Ruoyu Wang

Thiobencarb is a commonly used herbicide in Northern California rice fields. Released paddy water containing thiobencarb may pose ecological risks to non-targeted organisms. In this research, the Rice Water Quality Model (RICEWQ) is  equilibrium tested and then calibrated using monitoring data at field level. Then it is employed to assess the environmental fate and impacts of thiobencarb in the Colusa Basin, and the effects of different management practices on water use and thiobencarb exposures. The model predicted thiobencarb concentrations from rice fields for multiple years throughout the Basin, using input from California Pesticide Use Reporting (PUR) database, and assessed both ...


Development And Testing Of Additively Manufactured Aerospike Nozzles For Small Satellite Propulsion, Isaac W. Armstrong 2019 Utah State University

Development And Testing Of Additively Manufactured Aerospike Nozzles For Small Satellite Propulsion, Isaac W. Armstrong

All Graduate Theses and Dissertations

Automatic altitude compensation has been a holy grail of rocket propulsion for decades. Current state-of-the-art bell nozzles see large performance decreases at low altitudes, limiting rocket designs, shrinking payloads, and overall increasing costs. Aerospike nozzles are an old idea from the 1960’s that provide superior altitude-compensating performance and enhanced performance in vacuum, but have survivability issues that have stopped their application in satellite propulsion systems. A growing need for CubeSat propulsion systems provides the impetus to study aerospike nozzles in this application. This study built two aerospike nozzles using modern 3D metal printing techniques to test aerospikes at a ...


Hydrodeoxygenation Of Pinyon-Juniper Catalytic Pyrolysis Oil, Hossein Jahromi 2019 Utah State University

Hydrodeoxygenation Of Pinyon-Juniper Catalytic Pyrolysis Oil, Hossein Jahromi

All Graduate Theses and Dissertations

Catalytic hydrodeoxygenation (HDO), is an effective process to convert oxygenated compounds to hydrocarbons. This process is widely used for improving the negative properties of biomass-derived pyrolysis oils (bio-oils) such as high acidity, poor stability, and low heating value. During this process oxygen is removed from the bio-oil in the form of water, thus the liquid product of HDO process consists of aqueous phase and hydrocarbon phase that can be easily separated. Synthesis of efficient HDO catalyst has been a major challenge in the field of bio-oil upgrading. Red mud, which is an alkaline waste from alumina industry was used to ...


Pressure Loss Coefficients For Large Mitered Elbows With Diameters Ranging From 36-Inches To 144-Inches, Hayden J. Coombs 2019 Utah State University

Pressure Loss Coefficients For Large Mitered Elbows With Diameters Ranging From 36-Inches To 144-Inches, Hayden J. Coombs

All Graduate Theses and Dissertations

When designing a pipeline system, it is important to understand the pressure losses that will occur within the system. One common source of pressure loss is from elbow pipe fittings. There is extensive research available for pressure loss coefficients of elbow pipe fittings, but the research is derived from elbows with relatively smaller pipe diameters. The purpose of this research is to investigate pressure losses associated with larger diameter mitered elbows (36-inches to 144-inches). The dimensions for all mitered elbows considered in this research follow ANSI/AWWA C208-17 recommendations (AWWA 2017).

Due to the large size of the mitered elbows ...


Influence Of Mechanical Properties Of Paper Coating On The Crack At The Fold Problem, Seyyed Mohammad Hashemi Najafi 2019 University of Maine

Influence Of Mechanical Properties Of Paper Coating On The Crack At The Fold Problem, Seyyed Mohammad Hashemi Najafi

Electronic Theses and Dissertations

Paper coating layers are subject to various stresses and deformations in many converting processes such as calendering, printing, slitting, and folding of the paper. In some cases, products may crack during folding to generate a defect called cracking at the fold (CAF). The parameters that influence these defects are not well understood. The overall goal of this thesis is to better understand the CAF behavior as related to material properties of the coating layer.

A method was developed to produce free-standing pigmented coating layers thick enough to be tested in bending as well as tension. The mechanical properties of these ...


Measuring Nitrogen Transformation In Wastewater Impacted Streams Using In-Situ Benthic Chambers, Makenzi Beltran 2019 Utah State University

Measuring Nitrogen Transformation In Wastewater Impacted Streams Using In-Situ Benthic Chambers, Makenzi Beltran

All Graduate Theses and Dissertations

Acrylic chambers and metal frames were installed at the sediment-water interface of streams impacted by the effluent from wastewater reclamation facilities in order to determine nitrogen rates for nitrification, denitrification, assimilation, ANAMMOX, and DNRA. Each chamber was dosed with an isotopic form of nitrate (15NO3 - ), and both isotopic (15N) and non-isotopic (14N) samples were collected. The project locations included East Canyon Creek near the East Canyon Wastewater Reclamation Facility in Park City, Utah and Box Elder Creek near the Brigham City Wastewater Treatment Plant in Brigham City, Utah. Separate chamber measurements were conducted upstream and downstream ...


Impact Of Hydraulic Residence Time On Nitrate Removal In Pilot-Scale Woodchip Bioreactors, E. A. Martin, Morgan P. Davis, Thomas B. Moorman, Thomas M. Isenhart, Michelle L. Soupir 2019 Iowa State University

Impact Of Hydraulic Residence Time On Nitrate Removal In Pilot-Scale Woodchip Bioreactors, E. A. Martin, Morgan P. Davis, Thomas B. Moorman, Thomas M. Isenhart, Michelle L. Soupir

Agricultural and Biosystems Engineering Publications

Nitrate (NO3−N) export from row crop agricultural systems with subsurface tile drainage continues to be a major water quality concern. Woodchip bioreactors are an effective edge-of-field practice designed to remove NO3−N from tile drainage. The NO3−N removal rate of woodchip bioreactors can be impacted by several factors, including hydraulic residence time(HRT). This study examined the impact of three HRTs, 2 h, 8 h, and 16 h, on NO3−N removal in a set of nine pilot-scale woodchip bioreactors in Central Iowa. NO3−N concentration reduction from the inlet to the outlet was significantly different for all ...


Stability Analysis Of A More General Class Of Systems With Delay-Dependent Coefficients, Chi Jin, Keqin Gu, Islam Boussaada, Silviu-Iulian Niculescu 2019 Laboratoire des Signaux et Syst`emes (L2S) CentraleSup´elec-CNRS-Universit´e Paris Sud, 3 rue Joliot- Curie 91192 Gif-sur-Yvette cedex, France.

Stability Analysis Of A More General Class Of Systems With Delay-Dependent Coefficients, Chi Jin, Keqin Gu, Islam Boussaada, Silviu-Iulian Niculescu

SIUE Faculty Research, Scholarship, and Creative Activity

This paper presents a systematic method to analyse the stability of systems with single delay in which the coefficient polynomials of the characteristic equation depend on the delay. Such systems often arise in, for example, life science and engineering systems. A method to analyze such systems was presented by Beretta and Kuang in a 2002 paper, but with some very restrictive assumptions. This work extends their results to the general case with the exception of some degenerate cases. It is found that a much richer behavior is possible when the restrictive assumptions are removed. The interval of interest for the ...


Security Of Vehicular Platooning, Soodeh Dadras 2019 Utah State University

Security Of Vehicular Platooning, Soodeh Dadras

All Graduate Theses and Dissertations

Platooning concept involves a group of vehicles acting as a single unit through coordination of movements. While Platooning as an evolving trend in mobility and transportation diminishes the individual and manual driving concerns, it creates new risks. New technologies and passenger’s safety and security further complicate matters and make platooning attractive target for the malicious minds. To improve the security of the vehicular platooning, threats and their potential impacts on vehicular platooning should be identified to protect the system against security risks. Furthermore, algorithms should be proposed to detect intrusions and mitigate the effects in case of attack. This ...


Estimating Suspended Solids And Phosphorus Loading In Urban Stormwater Systems Using High-Frequency, Continuous Data, Anthony A. Melcher 2019 Utah State University

Estimating Suspended Solids And Phosphorus Loading In Urban Stormwater Systems Using High-Frequency, Continuous Data, Anthony A. Melcher

All Graduate Theses and Dissertations

The introduction of pavement, buildings, and other impervious surfaces to urban landscapes greatly influences the quantity and quality of urban stormwater runoff. In this study, we designed and implemented modern stormwater monitoring technologies to establish a “smart” stormwater sensor network within the Northwest Field Canal (NWFC), an urban water conveyance located in Logan, Utah, USA. This network was designed to collect flow and water quality data at high frequencies and simultaneously at multiple locations. The observatory’s innovative method of inter-site communication and changing sampling frequencies during storm events was able to capture short duration events at the upstream and ...


Revamping Timing Error Resilience To Tackle Choke Points At Ntc, Aatreyi Bal 2019 Utah State University

Revamping Timing Error Resilience To Tackle Choke Points At Ntc, Aatreyi Bal

All Graduate Theses and Dissertations

The growing market of portable devices and smart wearables has contributed to innovation and development of systems with longer battery-life. While Near Threshold Computing (NTC) systems address the need for longer battery-life, they have certain limitations. NTC systems are prone to be significantly affected by variations in the fabrication process, commonly called process variation (PV). This dissertation explores an intriguing effect of PV, called choke points. Choke points are especially important due to their multifarious influence on the functional correctness of an NTC system. This work shows why novel research is required in this direction and proposes two techniques to ...


Successful Factors For Native And Community College Transfer Students In Engineering Technology At A Four-Year University, Leendert Craig 2019 East Tennessee State University

Successful Factors For Native And Community College Transfer Students In Engineering Technology At A Four-Year University, Leendert Craig

Electronic Theses and Dissertations

Students who attend community colleges often transfer to 4-year universities seeking to earn a degree typically not offered at the community college level. Tennessee has 2 programs: the Tennessee Promise and the Tennessee Reconnect programs that offer students tuition-free access to the state’s community college system. Previous studies have been conducted to compare transfer students’ performances to that of native students and typically compared the students in all disciplines. This study seeks to compare transfer students (students who enter the participating university with 40 or more credit hours) to native students (students who initially enrolled or transferred into the ...


Investigation Of Thermoplastic Polymers And Their Blends For Use In Hybrid Rocket Combustion, Spencer D. Mathias 2019 Utah State University

Investigation Of Thermoplastic Polymers And Their Blends For Use In Hybrid Rocket Combustion, Spencer D. Mathias

All Graduate Theses and Dissertations

This thesis set out to find a blend of thermoplastics that had better combustion properties than the current ABS (acrylonitrile butadiene styrene) plastic or “Lego TM plastic” used by Utah State University. The current work is in an effort to eliminate toxic propellants from small space applications. High and low density polyethylene plastics were used because they are common plastic waste items. In this way rocket fuel can be made from these items to reduce the waste found in landfills. Three plastics were considered for replacement and as mixture components with the ABS plastic, namely low and high density polyethylene ...


Comparison Of Induced And Parasitic Drag On Wings With Minimum Induced Drag, Sarah A. Abdel-Motaleb 2019 Utah State University

Comparison Of Induced And Parasitic Drag On Wings With Minimum Induced Drag, Sarah A. Abdel-Motaleb

All Graduate Plan B and other Reports

Minimizing the induced drag for steady level flight is a variational problem that requires solving for the optimum lift distribution given a set of design constraints. From lifting-line theory, minimizing the induced drag is, in part, achieved by varying the Fourier coefficients used to describe the section lift. The elliptic lift distribution minimizes the induced drag for a wing with fixed weight and wingspan by setting all but the first coefficient to zero. If wingspan is allowed to vary, a negative third Fourier coefficient is utilized to reach an optimum lift distribution that further reduces the induced drag for stress-limited ...


Side Shear Strength Of Preformed Socket Connections Suitable For Vertical Precast Members, Zhao Cheng, Sri Sritharan 2019 Iowa State University

Side Shear Strength Of Preformed Socket Connections Suitable For Vertical Precast Members, Zhao Cheng, Sri Sritharan

Civil, Construction and Environmental Engineering Publications

Use of precast substructure in accelerated bridge construction (ABC) has been gaining popularity due to its advantages over traditional cast-in-place (CIP) construction. When using vertical precast members (e.g., columns and piles) in bridge substructure construction, they must be connected to the adjoining members (e.g., bent cap, pile cap, and abutment) reliably. To accomplish this goal and promote ease of construction, the preformed socket connection has been suggested. This connection is established by inserting the vertical precast member inside a preformed socket in the precast adjoining member and filling the socket with non-shrink, high-strength grout. Using specimens that modeled ...


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