Matching Items (104)
Description
This study examines the spatial and temporal patterns of the surface urban heat island (SUHI) intensity in the Phoenix metropolitan area and the relationship with land use land cover (LULC) change between 2000 and 2014. The objective is to identify specific regions in Phoenix that have been increasingly heated and cooled to further understand how LULC change influences the SUHI intensity. The data employed include MODerate-resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) 8-day composite June imagery, and classified LULC maps generated using 2000 and 2014 Landsat imagery. Results show that the regions that experienced the most significant LST changes during the study period are primarily on the outskirts of the Phoenix metropolitan area for both daytime and nighttime. The conversion to urban, residential, and impervious surfaces from all other LULC types has been identified as the primary cause of the UHI effect in Phoenix. Vegetation cover has been shown to significantly lower LST for both daytime and nighttime due to its strong cooling effect by producing more latent heat flux and less sensible heat flux. We suggest that urban planners, decision-makers, and city managers formulate new policies and regulations that encourage residential, commercial, and industrial developers to include more vegetation when planning new construction.
ContributorsWang, Chuyuan (Author) / Myint, Soe (Author) / Wang, Zhi-Hua (Author) / Song, Jiyun (Author) / College of Liberal Arts and Sciences (Contributor)
Created2016-02-26
Description
Studies on urban heat island (UHI) have been more than a century after the phenomenon was first discovered in the early 1800s. UHI emerges as the source of many urban environmental problems and exacerbates the living environment in cities. Under the challenges of increasing urbanization and future climate changes, there is a pressing need for sustainable adaptation/mitigation strategies for UHI effects, one popular option being the use of reflective materials. While it is introduced as one effective method to reduce temperature and energy consumption in cities, its impacts on multi-dimensional environmental sustainability and large-scale non-local effect are inadequately explored. This paper provides a synthetic overview of potential environmental impacts of reflective materials at a variety of scales, ranging from energy load on a single building to regional hydroclimate. The review shows that mitigation potential of reflective materials depends on a portfolio of factors, including building characteristics, urban environment, meteorological and geographical conditions, to name a few. Precaution needs to be exercised by city planners and policy makers for large-scale deployment of reflective materials before their environmental impacts, especially on regional hydroclimates, are better understood. In general, it is recommended that optimal strategy for UHI needs to be determined on a city-by-city basis, rather than adopting a “one-solution-fits-all” strategy.
ContributorsYang, Jiachuan (Contributor) / Wang, Zhi-Hua (Correspondent) / Kaloush, Kamil (Contributor)
Created2015-06-11
Description
Waste plastic is considered an environmental pollutant because it is not biodegradable. Therefore, there is increased interest in the use of recycled plastic in pavement construction. Polyethylene terephthalate (PET) is a thermoplastic polymer that is commonly used in the manufacturing of containers and bottles. Waste PET is a durable material that has shown enhancement in performance when introduced into asphalt binder and asphalt mixtures. However, PET particles tend to separate from asphalt because of differences in density, molecular structure, molecular weight, and viscosity, leading to inadequate dispersion of PET particles in the asphalt. This incompatibility between PET and asphalt causes segregation, where storage stability becomes an issue. To solve this problem, applying a surface activation on the PET using another abundant urban waste (waste vegetable oil) was examined in this study, showing this method can be effective to enhance PET-asphalt interactions and consequently the storage stability of PET-modified asphalt. To ensure proper surface activation, it is important to thoroughly understand the chemo-mechanics of asphalt containing PET particles as well as the underlying interaction mechanism at the molecular level. Therefore, this study integrates a multi-scale approach using computational modeling based on density functional theory along with laboratory experiments to provide an in-depth understanding of the mechanisms of interaction between surface-activated PET and asphalt. To do so, the efficacy of bio-oil treatment was examined in terms of both the surface-activation capability and the durability of the resulting PET-modified asphalt. It was found that the grafted bio-oil on the PET particles can make a strong interaction with bituminous composites, leading to enhancing the durability and extending the service life of asphalt pavement by reducing the diffusion of free radicals and moisture into the bulk. The study was further extended to study the effect of coating the PET with biochar, showing the latter coating can improve the mechanical properties of the PET-modified asphalt and the adsorption behavior of the PET for volatile organic compounds. The performance of the waste PET was compared with another widely used modifier, crumb rubber.
ContributorsAldagari, Sand (Author) / Fini, Elham (Thesis advisor) / Kaloush, Kamil (Committee member) / Ozer, Hasan (Committee member) / Arizona State University (Publisher)
Created2024
Description
As obesity rates continue to rise in adolescents and young children, the concern for poor future health of the younger population grows. Physical activity and improving nutrition are two ways to combat obesity rates, and the Sustainability via Active Gardening Education (SAGE) project addresses this in underserved and low-income communities in Maricopa County. This project employs a curriculum designed to promote physical activity and healthy eating for Early Care and Education (ECE) sites, most of which are daycares. Further, utilizing indicators of future health can also allow for us to understand and lower obesity rates. One indicator of future health is grip strength: greater grip strength is associated with healthier outcomes such as lower triglycerides, blood pressure, and body mass index. Grip strength has been observed in the older population; however, there are few studies looking at grip strength in younger children, namely preschoolers. As grip strength is a predictor of health, it follows that it should be observed in preschoolers, and improved, if possible, by factors such as physical activity, which would ultimately improve obesity rates. This study aimed to see if there was any relationship between physical activity and grip strength in preschoolers aged 3-5 years old. To do so, grip strength, hand length, height, weight, and information regarding physical activity of preschoolers enrolled in the SAGE project were collected.
Physical activity and grip strength were not found to be significantly associated in this study; however, hand length and hand strength were associated. Among secondary outcomes, it was observed that males of ages 3 to 5-years-old may have greater hand grip strength than females of the same age group. Although this was not statistically significant, there was a trend toward statistical significance. Small sample size hampered observation of expected relationships between hand grip strength and dominant hand of the participants, and hand grip strength was not significantly related with BMI. Future directions would consist of collecting longitudinal data, as well as calling back previous years’ participants for additional data, so that there is a larger sample size for data analysis.
ContributorsAtluri, Haarika (Author) / Lee, Rebecca (Thesis director) / Tucker, Derek (Committee member) / Cantu Garcia, Lisbeth (Committee member) / De Mello, Gabrielli (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2024-05