Green Streets, a stormwater management practice that is implemented within the public right of way, can effectively treat stormwater runoff on-site by closely mimicking natural processes. By providing multiple benefits, Green Streets can, purportedly, be a more sustainable alternative compared to conventional storm systems. However, there is no empirical research that evaluates how, or to what extent, the supposed or potential benefits of Green Streets are actually realized in projects built to date. Thus, planners and designers (or the public who are concerned about their watersheds) will find the literature on the subject to be of limited assistance in assessing many aspects of Green Street projects: their cost in terms of time, money, and resources; challenges; and whether the projects actually achieve the benefits touted by their proponents. This study is conducted to address these issues through two analyses. The first analysis looks at Green Street projects that were nominated by experts as the most successful additions to their communities. This portion of the study reveals that, in current practice, for a Green Street project to be successful, not only does it have to treat stormwater runoff but it also has to offer additional benefits, particularly in relation to the social aspects. The second analysis examines Green Street implementation processes in six sample cities, and four successful Green Street projects that appear to offer additional benefits were chosen for more detailed studies. Finally, a model process was developed with emphasis on the following: site analyses on multiple scales, the formation of interdisciplinary teams, and public outreach throughout the implementation process. The case studies elucidate the given challenges and suggest best practices for ensuring more sustainable outcomes in future projects. The study sheds light on the importance of incorporating multiple benefits in the implementation process and presents eight recommendations for successful Green Street implementation regarding the need for individuals who champion the project, interdisciplinary collaboration, opportunities for the public to voice their concerns, need of expanding the design scope, securing funds as delivering benefits, consideration of the maintenance plan, documentation of knowledge, and development of a model process. / Ph. D.

A typology of urban vacant land was developed using Roanoke, Virginia, as the study area. Because of its industrial past, topography and climate, Roanoke provides a range of vacant land types typical of those in many areas of the Mid-Atlantic, Eastern and Midwestern United States. A comprehensive literature review, field measurements and observations analysis and aerial photo interpretation and ground-truthing methods were utilized to identify and catalog vacant parcels of land and the results were mapped using i-Tree Canopy to identify the following types of urban vacant land: post-industrial (3.34 km2), derelict (4.01 km2), unattended with vegetation (17.3 km2), natural (2.78 km2), and transportation-related (5.01 km2). Unattended with vegetation sites are important resources as the health biodiversity found in natural sites benefits urban populations and they represent the highest plantable space. The redesign of post-industrial sites builds a city's image and transportation-related sites can contribute a green infrastructure network of open spaces. This typological study has significant implications for policy development, and for planners and designers seeking the best use for vacant urban land. The analysis of Roanoke's urban forest revealed around 210,000 trees on vacant land, a tree cover of 30.6%. These trees store about 107,000 tons of carbon (worth $7.65 million) and remove about 2,300 tons of carbon ($164,000), and about 91 tons of air pollution ($916,000) every year, which is high relative to other land uses. Trees on vacant land are estimated to reduce annual residential energy costs by $211,000 for the city's 97,000 residents and their structural value is estimated at $169 million. The methodology applied to assess ecosystem services in this study can also be used to assess ecosystem services of vacant land in other urban contexts and improve urban forest policies, planning, and the management of vacant land. The study findings support the inclusion of trees on vacant land providing a new vision of vacant urban land as a valuable ecological resource by demonstrating how green infrastructure can be used to enhance ecosystem health and promote a better quality of life for city residents. / Ph. D.

Anolis carolinensis was found to have three stereotyped and distinct territorial headbob patterns, referred to as Types A, B, and C. Each type had two variants, one in which the dewlap appeared mid-display and a second in which dewlap extension was absent. Use of these signals was examined in two contexts: a "male-alone” or advertisement context and a "male-male" or aggressive context. Context accounted for only minor amounts of the variability while display type explained the majority of unit variability. Display rate in advertisement was 0.3 displays/ min, half the displays were solitary, and half occurred in volleys of 2-6 displays. Dewlap extension accompanied 97% of the displays, and all three types of displays were used. Display rate was eightfold greater in male-male context, and the rate doubled again as males came within 20 cm of each other. At large separation distances (>60 cm), long volleys (4-9 displays) were common, Type C displays predominated, and dewlap extension accompanied 92% of the displays. At smaller separation distances (<20 cm), single displays predominated, volleys had fewer displays, displays were more evenly divided among the three types, and 93% of the displays had no dewlap extension. / Master of Science

The behavior and spatial relationships of 7 male and 22 females were described from 56 days of observation from focal and scan samples made between 0830 and 1830 h during May-July, 1993 at the Augusta Canal near Augusta, Georgia. Behavioral observations indicated that females primarily remain stationary (82.6%), while dividing the remainder of their time into travelling (7.7%), overt foraging (1.5%), and social interactions (8.2%). Though territorial, inter-female contacts were rare (0.3%) with more of a female’s time spent interacting with the resident male (3.2%) or in copula (3.9%). Females used three methods to capture prey: (1) sit-and-wait (84%), (2) opportunistic prey captures (11%), and (3) active search (5%). Dewlap extension is primarily used during aggressive interactions with females (60%), but rarely during courtship (2%) or copula (7%). Predation pressure was minimal as only four predator avoidances were observed. Home range volume and area for males averaged 68.5 m³ and 50.5 m², respectively. For females, home range volume and area were considerable smaller than males, averaging 7.8 m³ and 8.2 m², respectively. Intra-sexual overlap averaged 0% for males and 18% for females. Male snout-vent length (SVL) was positively correlated with male home range area and number of females overlapped. Female SVL did not correlate with either volume or area of territory. However, within a male’s territory, the largest female usually controlled the largest home range volume, perched highest, and maintained a green body color most often. Females tended to perch on smaller diameter limbs and to perch higher than males. / Master of Science

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Thesis advisor: Michael Grubb / With the implementation of the Inflation Reduction Act (IRA) raising concern of clean energy capital flight from the European Union, investigating the effects of US clean energy expansion policy on international investment shifts is a pertinent issue. This paper uses event studies to analyze debt capital market dynamics through green bond spreads, using conventional corporate and government bonds as separate benchmarks. It finds that the simultaneous extension of ITC and PTC policies in 2015, 2020, and 2021 did not consistently produce a significant effect on green bond markets in the US and EU. This implies that the implementation of clean energy policy in the US has an insignificant impact on green debt capital markets in the US and EU, although impacts on other investment channels cannot be ruled out. A further analysis on green investment sensitivity to interest rates indicated a significant negative sensitivity for green US firms only, although this was inconsistent across measures. / Thesis (BA) — Boston College, 2024. / Submitted to: Boston College. Morrissey School of Arts and Sciences. / Discipline: Economics. / Discipline: Departmental Honors.

Herbicide resistance, regulations on pesticide use, and cost of pesticides are all challenges for managing weeds in production agriculture. The use of cover crops (CC) has emerged as a promising integrated weed management tool to aid in weed suppression. There are many questions concerning the best management practices to reap the most benefits from CC. Research was conducted to determine if the application of a pre-plant herbicide as well as the type of CC planted would increase CC biomass and subsequent winter weed suppression. Early planting and selecting a cereal rye or a cereal rye-containing mixture are the most important factors to obtain the greatest CC biomass production. Additionally, the combination of a CC and a pre-plant herbicide increased weed suppression compared to a no CC (winter fallow) treatment or CC without a pre-plant herbicide. The difference in Palmer amaranth emergence between a rolled cereal rye CC or one that is left standing was also examined along with termination timing to achieve different CC biomass levels. Overall, greater CC biomass suppressed more Palmer amaranth, but treatments of rolled or standing or termination timing did not affect weed suppression consistently. Light penetration data also showed that greater CC biomass led to a decrease in light penetration through the CC canopy, which could be a factor in reducing Palmer amaranth emergence particularly at the greater CC biomass accumulation levels. Additionally, studies were conducted to investigate the effect of cereal rye CC termination timing (i.e., "planting green" being CC terminated at the time of soybean planting or "planting brown" being CC terminated 2 weeks prior to planting) on Palmer amaranth suppression, as well as to determine how termination timing influences herbicide program optimization. A delay in emergence and growth rate of Palmer amaranth was documented in the CC containing plots when compared to the no CC plots, but no differences were observed between the termination timings. Additionally, significantly lower Palmer amaranth densities were observed under CC containing plots when compared to the no CC treatments. Within CC treatment options, the most economical option was planting green with a single postemergence herbicide application, but overall, no CC treatments were more economical programs. Finally, research was conducted to understand weed and corn competition for nitrogen when hairy vetch + cereal rye CC was present. A range of side dress nitrogen fertilizer rates, weedy versus weed free herbicide programs, and CC versus no-CC treatments were compared. Overall, yield did not differ among treatments. Ear leaf and grain nitrogen was generally greater under weed free, CC, and when fertilized at or above yield goals respective of location. Despite these findings, early season weed control in corn is still necessary to achieve maximum potential yield. These studies indicate that CC biomass is consistently the most important factor for achieving weed suppression, and that CC results can vary in response to environmental and management effects. More research is therefore necessary to evaluate the effects of CC over greater periods of time. / Doctor of Philosophy / Herbicide resistant weeds are a major challenge for farmers across the globe. With the increased number of weed species resistant to multiple herbicides and the restrictions on pesticide use, farmers need more tools to control weeds. The use of cover crops (CC) to suppress weeds can be a viable integrated weed management tool for farmers. Although there are multiple benefits associated with CCs, there are also many drawbacks. CCs are an additional input cost for farmers, and require a greater level of management when compared to conventional systems. There are also many questions concerning best management practices in order to reap the benefits of CCs. Previous research indicates CC biomass is the most important factor in achieving weed suppression. Research trials were conducted at Virginia Tech to determine whether CC species as well as the application of preplant herbicide at the time of CC planting would affect CC biomass production as well as weed suppression. Cereal rye-containing plots produced more biomass overall compared to hairy vetch alone or crimson clover and earlier plantings accumulated greater CC biomass. Additionally, planting earlier was significant for CC biomass accumulation while applying a pre-plant herbicide was not. Weed suppression varied by species but was more successful when both a CC and pre-plant herbicide were applied as compared to no CC and no pre-plant herbicide application. Termination timing and mechanism of CC termination are both known to impact potential CC benefits. Many farmers roll their CC at termination, but it is unclear whether rolling is necessary for weed suppression benefits and soybean yield. Palmer amaranth counts were collected at four and six weeks after planting, as well as yield data across a range of cereal rye CC biomass levels, rolled or left standing at termination, and planted green (CC terminated at the time of planting) versus brown (CC terminated 2 weeks prior to planting). Light penetration measurements were also collected to observe changes in light availability through a CC canopy. Overall, CC treatments reduced Palmer amaranth emergence when compared to no CC, and suppression increased with greater CC biomass. Yield did not differ among treatments, therefore CC management can be tailored to weed suppression efforts. There were clear patterns of light penetration reduction as CC biomass increased. This reduction in light penetration could be part of the reason for the decreased Palmer amaranth emergence with greater CC biomass. Overall, the most important factor affecting weed suppression is accumulation of greater CC biomass. Research was conducted to determine differences in Palmer amaranth suppression due to CC termination timing, as growers have experimented with planting green while traditionally, planting brown or no CC at all was more common. Palmer amaranth groups were created and followed throughout a 10-week period to examine density and growth rates, which allowed various herbicide programs to be simulated and compared. A delay in emergence and growth rate of Palmer amaranth was documented in the CC containing plots when compared to the no CC plots, but no differences were observed between the termination timings. Additionally, significantly lower Palmer amaranth densities were observed under CC containing plots when compared to the no CC treatments. The most effective programs varied by year, but amongst CC options, planting green with a single POST herbicide was optimal, but overall, no CC treatments were more economical due to the expenses associated with CC seed and planting. If a grower is planning on using a CC, the recommendation is therefore to plant green, as lower costs were associated with this practice. In addition to weed suppression benefits, the potential for leguminous CC such as hairy vetch to provide nitrogen for the cash crop is another reason that farmers may plant CCs. However, the effect of a CC on weed competition for nitrogen is still unclear, as the nitrogen released by the CC can also stimulate weed emergence while the CC itself is physically suppressing weeds through its biomass. A study was established to evaluate the effects of CC or no CC, weedy or weed free herbicide programs, and six nitrogen side dress fertilizer rates on yield. Overall, greater concentrations of nitrogen in the ear leaf and in grain were found under CC, weed free, and when fertilized-to-yield goal for the respective locations. Yield was not responsive to treatment effects, and agronomic optimum analysis indicated that a side dress nitrogen to yield goal is still the best option even under CC to achieve optimal yields. Use of CCs is another tool for farmers to implement in their weed control programs. Proper management of CCs can result in increased weed suppression and provide other benefits not examined in this document. However, varying results by location calls for further research to explore the intricacies of CC management and its effect not only on other weed species, but also on other major cash crops.

This research addresses green communication issues, including energy efficiency, peak-to-average power ratio (PAPR) reduction and power amplifier (PA) linearization. Green communication is expected to be a primary goal in next generation cellular systems because it promises to reduce operating costs. The first key issue is energy efficiency of distributed antenna systems (DASs). The power consumption of high power amplifiers (HPAs) used in wireless communication systems is determined by the transmit power and drain efficiency. For unequal power allocation of orthogonal frequency division multiplexing (OFDM), the drain efficiency of the PA is determined by the PAPR and hence by the power distribution. This research proposes a PAPR-aware energy-efficient resource allocation scheme for joint orthogonal frequency division multiple access (OFDMA)/space division multiple access (SDMA) downlink transmission from DASs. Grouping-based SDMA is applied to exploit the spatial diversity while avoiding performance degradation from correlated channels. The developed scheme considers the impact of both system data rate and effective power consumption on the PAPR during resource allocation. We also present a suboptimal joint subcarrier and power allocation algorithm to facilitate implementation of power-efficient multi-channel wireless communications. By solving Karush-Kuhn-Tucker conditions, a closed-form solution for the power allocation of each remote radio head is obtained. The second key issue is related with PAPR reduction in the massive multiple-input multiple-output (MIMO) systems. The large number of PAs in next generation massive MIMO cellular communication system requires using inexpensive PAs at the base station to keep array cost reasonable. Large-scale multiuser (MU) MIMO systems can provide extra spatial degrees-of-freedom (DoFs) for PAPR reduction. This work applies both recurrent neural network (RNN)- and semidefinite relaxation (SDR)-based schemes for different purposes to reduce PAPR. The highly parallel structure of RNN is proposed in this work to address the issues of scalability and stringent requirements on computational times in PAPR-aware precoding problem. An SDR-based framework is proposed to reduce PAPR that accommodates channel uncertainties and intercell coordination. Both of the proposed structures reduce linearity requirements and enable the use of lower cost RF components for large-scale MU-MIMO-OFDM downlink. The third key issue is digital predistortion (DPD) in the massive MIMO systems. The primary source of nonlinear distortion in wireless transmitters is the PA, which is commonly modeled using polynomials. Conventional DPD schemes use high-order polynomials to accurately approximate and compensate for the nonlinearity of the PA. This is impractical for scaling to tens or hundreds of PAs in massive MIMO systems. This work therefore proposes a scalable DPD method, achieved by exploiting massive DoFs of next generation front ends. We propose a novel indirect learning structure which adapts the channel and PA distortion iteratively by cascading adaptive zero-forcing precoding and DPD. Experimental results show that over 70% of computational complexity is saved for the proposed solution, it is shown that a 3rd order polynomial with the new solution achieves the same performance as the conventional DPD using 11th order polynomial for a 100x10 massive MIMO configuration. / Ph. D. / The global climate change has emerged as a critical issue over the last decades. The increasing popularity of wireless communication networks, has resulted in information and communication technology becoming a non-negligible contributor to the overall carbon footprint. The increasing number of base stations and remote radio heads leads to higher operating expenditure mainly because of the higher energy consumption. This growth can be attributed not only to the increase in the number of smart devices in emerging economies, but also to the growth of shared multimedia data and online games. The wireless industry needs significant improvements in the energy efficiency of base stations and other network infrastructure to compensate for the increased energy demands from the network growth. Therefore, designing energy-efficient communication systems has become a critical issue for 5G, which promises massive deployment of smart devices served new infrastructure elements. In this dissertation, we primarily investigate the theoretical foundations and practical algorithms for the next generation wireless technologies, and discuss the impact of ongoing trends in cellular communications, such as shrinking cell sizes and multi-antenna system deployments, on energy-efficient 5G networks. The theoretical development and wireless algorithms are valuable for the deployment of next generation wireless network systems