Matching Items (60)
Description
This study investigated the difference in biofilm growth between pristine polypropylene microplastics and aged polypropylene microplastics. The microplastics were added to Tempe Town Lake water for 4 weeks. Each week the microplastic biofilms were quantified. Comparing the total biofilm counts, the results showed that the aged microplastic biofilms were larger than the pristine each week. By week 3 the aged microplastic counts had almost doubled in size increasing from 324 to 626 Colony Forming Units per gram in just one week. There was a significant difference in the diversity found from week 1 to week 4. About 40% of the diversity for the pristine microplastic biofilm was seen as light-yellow dots and about 60% of these dots were seen on the aged microplastic biofilms in both weeks. As the microplastics were submerged in the lake water, new phenotypes emerged varying from week 1 to week 4 and from pristine to aged microplastic biofilms. Generally, it was found that as the microplastics stay in the environment there is more biofilm on the particles. The aged microplastics have a larger amount of biofouling, and the pristine microplastic biofilms were found to have more diversity of phenotypes.
ContributorsMushro, Noelle Sararose (Author) / Perreault, Francois (Thesis director) / Jay, Oswald (Committee member) / Civil, Environmental and Sustainable Eng Program (Contributor) / School of Sustainable Engineering & Built Envirnmt (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Cerebral lateralization describes the asymmetries between the two halves of the brain which results in side-specialized processing of certain functions. This phenomenon provides a selective advantage by promoting enhanced cognitive abilities. However, due to the plastic nature of lateralization, an individual’s lateralization is highly subject to change by many external factors, such as pollution, throughout its life. Additionally, lateralized regions are dependent on different contexts, so lateralized elements do not all experience the same effects. A common pollutant found worldwide is bisphenol-A (BPA), a critical component of many plastics. BPA is a known endocrine disruptor that can agonize and antagonize the functions of sex steroids. Other studies have demonstrated the importance of sex steroids in regulating the development of cerebral lateralization; BPA may similarly affect lateralization. A popular research animal for studying toxicology is the zebrafish. Its advantages include a fully sequenced genome, many human orthologs, and more importantly, expresses lateralized behaviors that are indicative of the strength of its cerebral lateralization. This experiment analyzed the effects of BPA exposure on visual lateralization of zebrafish. Given the role that sex steroids play in moderating lateralization, it was hypothesized that exposing zebrafish to BPA would diminish the strength of lateralization in the brain which would translate into reduced behavioral lateralization. To test this, one group was exposed to 0.01 mg/L BPA for one week and compared against a control group in their eye preference when approaching a visual cue. Two settings, a foraging context and a social context, were utilized to examine the scope of impairment in lateralization. The control group in both settings displayed similar strengths in behavioral lateralization with a left eye preference. However, the lateralized response faded completely with BPA treatment. This experiment demonstrates that BPA induces loss of lateralization and possesses similar impacts on mechanisms controlling investigatory behavior in these two contexts. Wild populations may encounter higher concentrations of BPA, and although there is greater variability in these exposures, this experiment proves that exposure even beyond critical periods of development can impair lateralization. Additional research will have to be conducted to identify the effects of BPA on other lateralized behaviors and sensory modalities to pinpoint the exact mechanisms through which BPA influences lateralization.
ContributorsHuang, Alexander (Author) / Martins, Emilia (Thesis director) / Suriyampola, Piyumika (Committee member) / Conroy-Ben, Otakuye (Committee member) / School of Life Sciences (Contributor) / School of Molecular Sciences (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
To successfully launch and maintain a long-term colony on Mars, Martian agricultural systems need to be capable of sustaining human life without requiring expensive deliveries from Earth. There is a need for more studies on this topic to make this a feasible mission. This thesis aims to study from a high level one such agricultural system, specifically examining the requirements and flow of Nitrogen, Phosphorus and Potassium required to sustain a given human colony size. We developed a Microsoft Excel based model that relates human nutritional needs to the amount available in food crops and in turn the amount of Martian soil required for agriculture. The model works by inputting the number of humans, and then utilizing the built-in calculations and datasets to determine how much of each nutrient is needed to meet all nutritional needs of the colony. Using that information, it calculates the amount of plants needed to supply the nutrition and then calculates the amount of nutrients that would be taken from the soil. It compares the Martian regolith to the nutrient uptake, accounting for inedible biomass from the plants and human waste that can be added to the regolith. Any deficiencies are used to determine if and how much fertilizer should be added to the system initially and over time. Using the total amount of plants and the number of harvests, the amount of Martian land required for sustaining the colony is computed. These results can be used as a building block to enable the successful design of an agricultural system on Mars.
ContributorsGarland, Michael (Co-author) / Zinke, Sarah (Co-author) / Muenich, Rebecca (Thesis director) / Perreault, Francois (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
In order to produce efficient reverse osmosis membranes, it is necessary to minimize the effects of outside factors on the membrane surface that can reduce the flux of water through the membrane. One such problem is fouling. Fouling happens when particles are deposited on the membrane surface, blocking water flow through the membrane. Over time, the collection of foulants will prevent water through the membrane, increasing the amount of energy required in the system. Microgel, a heat-responsive colloidal gel, shows promise as an anti-foulant coating as it possesses functional groups similar to the membrane and compatible with common foulants and changes volume due to temperature differences. By coating the membrane with the microgel, foulants will attach to the functional groups of the microgel instead of those of the membrane Our hypothesis is that the change in volume of the microgel with different temperatures will help reduce and remove foulants. By functionalizing the surface of the membrane and the microgel, the microgel can covalently bond to the membrane surface and avoid detachment under reverse osmosis conditions. Microgel-coated reverse osmosis membranes have been fluorescently fouled to measure the decrease in foulants with heated crossflow under fluorescent microscopy. This process has shown a 50% decrease in fluorescence on the surface of the membrane indicating a decrease in foulants due to the presence of microgel. Under cross-flow conditions with a low flow rate, the microgel remains on the functionalized membrane for 8 hours with similar anti-fouling performance as the dip-coating process.
ContributorsKraetz, Andrea Nicole (Author) / Thomas, Marylaura (Thesis director) / Perreault, Francois (Committee member) / Chemical Engineering Program (Contributor) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The loading provisions were compared between the ASCE 7-10 standard and ASCE 7-16 standard. Two different structural models were considered: an office building with a flat roof located in Tempe and a community center with a gable roof located in Flagstaff. The following load types were considered: dead, live, wind, and snow loads. The only major changes between the standards were found in the wind load calculations. The winds loads were reduced by approximately 22% for the office building in Tempe and 37% for the community center in Flagstaff. A structural design was completed for the frame of the Flagstaff community building. There was a 19% reduction in cost from the design using ASCE 7-10 provisions compared to the design utilizing ASCE 7-16 provisions, leading to a saving of $7,599.17. The reduction in loading, and subsequently more cost-effective design, is attributed to the reduction in basic wind speed for the region and consideration of the ground elevation factor. The introduction of the new ASCE 7-16 standard was met with criticism, especially over the increase in specific coefficients in the wind load and seismic load chapters. Proponents of ASCE 7-16 boast that the new chapter on tsunami loads, new maps for various environmental loads, and a new electronic hazard are some of the merits of the newest standard. Others still question whether the complexity of the provisions is necessary and call for further improvements for the wind and seismic provisions. While tension exists in the desire for a simple standard, ASCE 7-16 prioritizes in having its provisions provide economical and reliable results. More consideration could be devoted to developing a more convenient standard for users. Regardless, engineering professionals should be able to adapt alongside newly developed practices and newly discovered data.
ContributorsCajegas, Cyam Joshua Dato (Author) / Rajan, Subramaniam (Thesis director) / Neithalath, Narayanan (Committee member) / Civil, Environmental and Sustainable Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Consumers purchase point-of-use (POU) devices to further improve the quality of water provided by the tap. As awareness increases of harmful contaminants, an emerging market of advanced POU with claims of removing beyond what a typical activated carbon filter is capable of, such as heavy metals. This research compares four commercially available pitcher filters; two that claim to remove arsenic and hexavalent chromium and two without such claims. Arsenate (As (V)) and hexavalent chromium (Cr (VI)) co-occur in natural geologic formations and are known to have harmful effects on humans when ingested. Pitcher filters Epic Water Filter and Aquagear had claims of removing both As (V) and Cr (VI) up to 99% with a capacity of nearly 200 gallons. In contrast, pitcher filters Brita and Pur had no claims for removal of As(V) and Cr(VI) with a 40-gallon lifespan. A series of experiments were conducted to first determine the efficiency of each filter, then to add the ability or improve removal of As(V) and Cr(VI) in one filter for future design implementations. Experiment 1 was conducted by treating 100 gallons of spiked tap water (50 ppb for As (V) and 100 ppb for Cr (VI)) with each filter. All four pitcher filters showed low performance, resulting in Pur with the lowest removal percentage of 2% and Aquagear with the highest percentage 16% for As (V). For Cr (VI) Pur performed the worst with a removal of 5% and Brita had the best performance of 15%. The functionality of Brita was improved by embedding a selective ion exchange media, which when nanotized successfully removed Cr (VI) in previous studies. The optimal mass of resin to add to the pitcher was experimentally determined as 18.9 grams through Experiment 2. Finally, Experiment 3 compared an alternative placement of the resin material using the same 18.9 grams. The performance in Experiment 3 was significantly worse than Experiment 2. The final recommendation for future design implementation was to add 18.9 grams of SIR-700 resin below the filter media for optimum performance. Overall, the results demonstrate the limited removal of As(V) and Cr(VI) by the four commercial pitcher filters and show that by adding selective ion exchange media, the POUs can be nano-enabled to effectively remove As(V) and Cr(VI) from water.
ContributorsDietrich, Lisa Keri (Author) / Westerhoff, Paul (Thesis director) / Perreault, Francois (Committee member) / Civil, Environmental and Sustainable Engineering Program (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Asphalt pavements deteriorate over time and are subjected to various distresses like rutting, fatigue cracking, stripping, raveling, etc. In this study, an experiment to indirectly assess aggregate stripping was completed in order to evaluate the effect of type of binder, and aging on the binder-aggregate bond under dry conditioning. The asphalts used in the study are commonly used in the state of Arizona, which included both non-polymer modified and polymer modified asphalts. The phenomenon of stripping was simulated using the Bitumen Bond Strength Test (BBS) and evaluated for Arizona binders. The BBS test is a simple test that measures the "pull-off" tensile strength of the bond between asphalt and the aggregate. Polymer modified binders were found to have lower pull-off strength in comparison to the non-modified or neat binder which were found to possess greater pull-off strength, but lower elasticity, causing the failure to become brittle and spontaneous. However, when aged binder was used, the bond strength expectedly reduced for non-polymer modified asphalts but surprisingly increased for polymer modified asphalts. Both un-aged neat and polymer modified binders were observed to have a cohesive failure whereas only the aged polymer modified binders failed in cohesion. The aged non-polymer modified binders were seen to have an adhesive failure.
ContributorsPonce, Esai Jonathon (Author) / Kaloush, Kamil (Thesis director) / Gundla, Akshay (Committee member) / Civil, Environmental and Sustainable Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This paper introduces an excel tool created to improve the accuracy of electrical subcontracting prices for solar photovoltaic energy systems while also minimizing the time needed to create these price estimations. The need for improved precision, specifically during the early stages of a project, is examined and the paper also goes into detail about the components and pricing method that are incorporated into the excel tool. Lastly, the results of the price estimation tool are compared to real bids and recommendations are made for improvement to the tool.
ContributorsJohnson, Eric Allen (Author) / Fraser, Matthew (Thesis director) / Hjelmstad, Keith (Committee member) / Hughes, Jeff (Committee member) / Civil, Environmental and Sustainable Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Midwestern cities are in decline, with shrinking populations and corresponding disinvestment. Many organizations and city governments are working on addressing the problem of vacancy while bringing these urban areas into the global economy. The EcoBlock Organization (EBO), a St. Louis-based non-profit, proposes block-level redevelopment as a method of fostering community and economic development while minimizing the impact on the environment. The EcoCode is a block-level form-based code describing the vision of the EBO and its implementation. This vision is centered around eight key design principles: energy, public health, social, urban design, water, transportation, resilience, and landscape. It manifests as an EcoBlock: a block of buildings surrounding a shared green space, connected by an energy grid and a shared geothermal loop with the goal of net-zero energy. The residences are a mix of building types for a variety of incomes and some building space will be designated for shared use, all physically reflecting the historic design of houses in the city in which the EcoBlock is implemented. Specifications like design, building placement, and mechanisms by which to strive towards net-zero energy and water will be determined in each location in which the EcoBlock is developed. The EcoCode describes the process and the desired outcome, providing a framework for this implementation.
The EcoCode resembles a typical form-based code in structure, but at a smaller geographic scale. General Provisions describes the context of the surrounding area that must be assessed before choosing to create an EcoBlock. Development and Adoption strategy explains the evolving role of the EBO and how the realization of this design is currently envisioned. Regulating Block, Block Development Standards, Building Envelope Standards, and Building Development Standards describe the detail that will need to be developed for the physical aspects of each block. Streetscape Standards describe the vision of the EBO as applicable to the streets surrounding an EcoBlock. Finally, the Sustainability Standards contain the contribution of each board member of the EBO with their unique expertise on implementing the design principles.
As a supplement to The EcoCode itself, this document contains three topics for case studies looking into the feasibility of the EcoBlock as a whole: shared space, net-zero energy, and mixed-income housing. Shared space development and management uses Montgomery Park in Boston to show the potential of community-based organization while warning against gentrification. The West Village campus of the University of California in Davis shows the technical possibility and the financial challenges of a net-zero community. Brogården, an affordable housing community in Sweden, demonstrates the possibility for decreasing energy consumption in public housing. Finally, Via Verde in New York City is an example of combining health, green space, and affordability in a mixed-income housing development. Though there is not yet an example of a fully implemented EcoBlock, these case studies speak to the challenges and the facilitators that the EBO will likely face.
The EcoCode resembles a typical form-based code in structure, but at a smaller geographic scale. General Provisions describes the context of the surrounding area that must be assessed before choosing to create an EcoBlock. Development and Adoption strategy explains the evolving role of the EBO and how the realization of this design is currently envisioned. Regulating Block, Block Development Standards, Building Envelope Standards, and Building Development Standards describe the detail that will need to be developed for the physical aspects of each block. Streetscape Standards describe the vision of the EBO as applicable to the streets surrounding an EcoBlock. Finally, the Sustainability Standards contain the contribution of each board member of the EBO with their unique expertise on implementing the design principles.
As a supplement to The EcoCode itself, this document contains three topics for case studies looking into the feasibility of the EcoBlock as a whole: shared space, net-zero energy, and mixed-income housing. Shared space development and management uses Montgomery Park in Boston to show the potential of community-based organization while warning against gentrification. The West Village campus of the University of California in Davis shows the technical possibility and the financial challenges of a net-zero community. Brogården, an affordable housing community in Sweden, demonstrates the possibility for decreasing energy consumption in public housing. Finally, Via Verde in New York City is an example of combining health, green space, and affordability in a mixed-income housing development. Though there is not yet an example of a fully implemented EcoBlock, these case studies speak to the challenges and the facilitators that the EBO will likely face.
ContributorsJohn, Raveena Susan (Author) / Allenby, Braden (Thesis director) / Redman, Charles (Committee member) / Garcia, Margaret (Committee member) / Civil, Environmental and Sustainable Engineering Program (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Arizona's transportation infrastructure is in need of an update. The American Society of Civil Engineers (ASCE) State Infrastructure 2017 Report Card scores Arizona's roads at a D+ and Arizona's bridges at a B. These grades are indicative that the serviceability levels of the roads and bridges are less than adequate. These grades may seem tolerable in light of a national bridge C+ grade and a national road D grade, but the real problem lies in Arizona's existing funding gap that is in danger of exponentially increasing in the future. With an influx of vehicles on Arizona's roads and bridges, the cost of building, repairing, and maintaining them will grow and cause a problematic funding shortage. This report explores the current state of Arizona's roads and bridges as well as the policy and funding sources behind them, using statistics from the ASCE infrastructure report card and the Federal Highway Administration. Additionally, it discusses how regular, preventative maintenance for transportation infrastructure is the economically responsible choice for the state because it decreases delays and fuel expenses, prevents possible catastrophes, and increases human safety. To prioritize preventative transportation infrastructure maintenance, the common mentality that allows it to be sidelined for more newsworthy projects needs to be changed. Along with gaining preventative maintenance revenues through increasing vehicular taxes and fees, encouraging transportation policymakers and politicians to make economic decisions in favor of maintenance rather than waiting until failure is a reliable way to encourage regular, preventative maintenance.
ContributorsBurdett, Courtney (Author) / Hjelmstad, Keith (Thesis director) / Pendyala, Ram (Committee member) / Civil, Environmental and Sustainable Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05