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Creep characteristics and shear strength of recycled asphalt blends

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The trend towards using recycled materials on new construction projects is growing as the cost for construction materials are ever increasing and the awareness of the responsibility we have to be good stewards of our environment is heightened. While recycled

The trend towards using recycled materials on new construction projects is growing as the cost for construction materials are ever increasing and the awareness of the responsibility we have to be good stewards of our environment is heightened. While recycled asphalt is sometimes used in pavements, its use as structural fill has been hindered by concern that it is susceptible to large long-term deformations (creep), preventing its use for a great many geotechnical applications. While asphalt/soil blends are often proposed as an alternative to 100% recycled asphalt fill, little data is available characterizing the geotechnical properties of recycled asphalt soil blends. In this dissertation, the geotechnical properties for five different recycled asphalt soil blends are characterized. Data includes the particle size distribution, plasticity index, creep, and shear strength for each blend. Blends with 0%, 25%, 50%, 75% and 100% recycled asphalt were tested. As the recycled asphalt material used for testing had particles sizes up to 1.5 inches, a large 18 inch diameter direct shear apparatus was used to determine the shear strength and creep characteristics of the material. The results of the testing program confirm that the creep potential of recycled asphalt is a geotechnical concern when the material is subjected to loads greater than 1500 pounds per square foot (psf). In addition, the test results demonstrate that the amount of soil blended with the recycled asphalt can greatly influence the creep and shear strength behavior of the composite material. Furthermore, there appears to be an optimal blend ratio where the composite material had better properties than either the recycled asphalt or virgin soil alone with respect to shear strength.

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2011

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Community supported agriculture membership: characterizing food and sustainability behaviors

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Community Supported Agriculture programs (CSAs) have become a viable local source of fresh agricultural goods and represent a potentially new way to improve fruit and vegetable consumption among individuals and families. Studies concerning CSAs have focused mainly on characteristics of

Community Supported Agriculture programs (CSAs) have become a viable local source of fresh agricultural goods and represent a potentially new way to improve fruit and vegetable consumption among individuals and families. Studies concerning CSAs have focused mainly on characteristics of the typical CSA member and motivations and barriers to join a CSA program. The purpose of this study was to examine whether behavior and attitudinal differences existed between current CSA members and a nonmember control group. Specifically, ecological attitudes, eating out behaviors, composting frequency, and family participation in food preparation were assessed. This study utilized an online survey comprising items from previous survey research as well as newly created items. A total of 115 CSA member and 233 control survey responses were collected. CSA members were more likely to be older, have more education, and have a higher income than the control group. The majority of CSA members surveyed were female, identified as non-Hispanic and Caucasian, earned a higher income, and reported being the primary food shopper and preparer. The majority of members also noted that the amount and variety of fruits and vegetables they ate and served their family increased as a result of joining a CSA. CSA members were more ecologically minded compared to the control group. Frequency of eating out was not significantly different between groups. However, eating out behaviors were different between income categories. CSA members spent significantly more money at each meal eaten away from home and spent significantly more money on eating out each week. In both cases, controlling for income attenuated differences between groups. CSA members composted at a significantly higher rate and took part in other eco-friendly behaviors more often than the control group. Finally, no significant difference was evident between the two groups when analyzing family involvement in food preparation and meal decision-making. Overall, some significant attitudinal and behavioral differences existed between CSA members and non-CSA members. Further research is necessary to examine other distinctions between the two groups and whether these differences occur as a result of CSA membership.

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2011

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Constructing a model for small scale fish farmers

Description

Fish farming is a fast growing industry, which, although necessary to feed an ever growing worldwide population, has its share of negative environmental consequences, including the release of drugs and other waste into the ocean, the use of fish caught

Fish farming is a fast growing industry, which, although necessary to feed an ever growing worldwide population, has its share of negative environmental consequences, including the release of drugs and other waste into the ocean, the use of fish caught from the ocean to feed farm raised fish, and the escape of farm raised fish into natural bodies of water. However, the raising of certain types of fish, such as tilapia, seems to be an environmentally better proposition than raising other types of fish, such as salmon. This paper will explore the problems associated with fish farming, as well as offer a model, based on the literature, and interviews with fish farmers, to make small-scale fish farming both more environmentally, and more economically, sustainable. This paper culminates with a model for small-scale, specifically semi-subsistence, fish farmers. This model emphasizes education of the fish farmers, as well as educators learning from the fish farmers they interact with. The goal of this model is to help these fish farmers become both more environmentally and economically sustainable.

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2011

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Operationalizing neighborhood resiliency: a grass-roots approach

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This research addresses the ability for neighborhoods to assess resiliency as it applies to their respective local areas. Two demographically and economically contrasting neighborhoods in Glendale, Arizona were studied to understand what residents' value and how those values link to

This research addresses the ability for neighborhoods to assess resiliency as it applies to their respective local areas. Two demographically and economically contrasting neighborhoods in Glendale, Arizona were studied to understand what residents' value and how those values link to key principles of resiliency. Through this exploratory research, a community-focused process was created to use these values in order to link them to key principles of resiliency and potential measureable indicators. A literature review was conducted to first assess definitions and key principles of resiliency. Second, it explored cases of neighborhoods or communities that faced a pressure or disaster and responded resiliently based on these general principles. Each case study demonstrated that resiliency at the neighborhood level was important to its ability to survive its respective pressure and emerge stronger. The Heart of Glendale and Thunderbird Palms were the two neighborhoods chosen to test the ability to operationalize neighborhood resiliency in the form of indicators. First, an in-depth interview was conducted with a neighborhood expert to understand each area's strengths and weaknesses and get a context for the neighborhood and how it has developed. Second, a visioning session was conducted with each neighborhood consisting of seven participants to discuss its values and how they relate to key principles of resiliency. The values were analyzed and used to shape locally relevant indicators. The results of this study found that the process of identifying participants' values and linking them to key principles of resiliency is a viable methodology for measuring neighborhood resiliency. It also found that indicators and values differed between the Heart of Glendale, a more economically vulnerable yet ethnically diverse area, than Thunderbird Palms, a more racially homogenous, middle income neighborhood. The Heart of Glendale valued the development of social capital more than Thunderbird Palms which placed a higher value on the condition of the built environment as a vehicle for stimulating vibrancy and resiliency in the neighborhood. However, both neighborhoods highly valued public education and providing opportunities for children to be future leaders in their local communities.

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2011

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Community food resource assessment in Central City South, Phoenix: a study of community capacity building

Description

Many studies have shown that access to healthy food in the US is unevenly distributed and that supermarkets and other fresh food retailers are less likely to be located in low-income minority communities, where convenience and dollar stores are more

Many studies have shown that access to healthy food in the US is unevenly distributed and that supermarkets and other fresh food retailers are less likely to be located in low-income minority communities, where convenience and dollar stores are more prevalent grocery options. I formed a partnership with Phoenix Revitalization Corporation, a local community development organization engaged in Central City South, Phoenix, to enhance the community's capacity to meet its community health goals by improving access to healthy food. I used a community-based participatory approach that blended qualitative and quantitative elements to accommodate collaboration between both academic and non-academic partners. Utilizing stakeholder interviews, Nutrition Environment Measures Surveys (NEMS), and mapping to analyze the community's food resources, research revealed that the community lacks adequate access to affordable, nutritious food. Community food stores (n=14) scored an average of 10.9 out of a possible 54 points using the NEMS scoring protocol. The community food assessment is an essential step in improving access to healthy food for CCS residents and provides a baseline for tracking progress to improve residents' food access. Recommendations were drafted by the research partnership to equip and empower the community with strategic, community-specific interventions based on the research findings.

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2011

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Restaurant industry sustainability: barriers and solutions to sustainable practice indicators

Description

Restaurants have a cumulative impact on the environment, economy, and society. The majority of restaurants are small-to-medium enterprises (SMEs). Review of sustainability and industry literature revealed that considering restaurants as businesses with sustainable development options is the most appropriate way

Restaurants have a cumulative impact on the environment, economy, and society. The majority of restaurants are small-to-medium enterprises (SMEs). Review of sustainability and industry literature revealed that considering restaurants as businesses with sustainable development options is the most appropriate way to evaluate their sustainable practices or lack thereof. Sustainable development is the means by which a company progresses towards achieving an identified set of sustainability goals and harnesses competitive advantage. The purpose of this thesis is to identify barriers to implementing sustainable practices in restaurants, and explore ways that restaurateurs can incorporate sustainable business practices. Energy consumption, water use, waste production, and food throughput are the four sustainability indicators addressed in this thesis. Interviews were conducted with five Tempe, Arizona restaurants, two of which consider their operations to be sustainable, and three of which are traditional restaurants. Results show that for traditional restaurants, the primary barriers to implementing sustainable business practices are cost, lack of awareness, and space. For sustainability-marketed restaurants, the barriers included a lack of knowledge or legal concerns. The sustainability-marketed restaurants have energy-efficient equipment and locally source a majority of their food purchases. There is a marked difference between the two types of restaurants in perception of barriers to sustainable business practices. I created a matrix to identify whether each indicator metric was applicable and present at a particular restaurant, and the potential barriers to implementing sustainable practices in each of the four indicator areas. Restaurants can use the assessment matrix to compare their current practices with sustainable practices and find ways to implement new or enhance existing sustainable practices. Identifying the barriers from within restaurants increases our understanding of the reasons why sustainable practices are not automatically adopted by SMEs. The assessment matrix can help restaurants overcome barriers to achieving sustainability by highlighting how to incorporate sustainable business practices.

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2011

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Chip level implementation techniques for radiation hardened microprocessors

Description

Microprocessors are the processing heart of any digital system and are central to all the technological advancements of the age including space exploration and monitoring. The demands of space exploration require a special class of microprocessors called radiation hardened microprocessors

Microprocessors are the processing heart of any digital system and are central to all the technological advancements of the age including space exploration and monitoring. The demands of space exploration require a special class of microprocessors called radiation hardened microprocessors which are less susceptible to radiation present outside the earth's atmosphere, in other words their functioning is not disrupted even in presence of disruptive radiation. The presence of these particles forces the designers to come up with design techniques at circuit and chip levels to alleviate the errors which can be encountered in the functioning of microprocessors. Microprocessor evolution has been very rapid in terms of performance but the same cannot be said about its rad-hard counterpart. With the total data processing capability overall increasing rapidly, the clear lack of performance of the processors manifests as a bottleneck in any processing system. To design high performance rad-hard microprocessors designers have to overcome difficult design problems at various design stages i.e. Architecture, Synthesis, Floorplanning, Optimization, routing and analysis all the while maintaining circuit radiation hardness. The reference design `HERMES' is targeted at 90nm IBM G process and is expected to reach 500Mhz which is twice as fast any processor currently available. Chapter 1 talks about the mechanisms of radiation effects which cause upsets and degradation to the functioning of digital circuits. Chapter 2 gives a brief description of the components which are used in the design and are part of the consistent efforts at ASUVLSI lab culminating in this chip level implementation of the design. Chapter 3 explains the basic digital design ASIC flow and the changes made to it leading to a rad-hard specific ASIC flow used in implementing this chip. Chapter 4 talks about the triple mode redundant (TMR) specific flow which is used in the block implementation, delineating the challenges faced and the solutions proposed to make the flow work. Chapter 5 explains the challenges faced and solutions arrived at while using the top-level flow described in chapter 3. Chapter 6 puts together the results and analyzes the design in terms of basic integrated circuit design constraints.

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2013

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Urban development and sustainable water management of southwest cities

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Water is the defining issue in determining the development and growth of human populations of the Southwest. The cities of Las Vegas, Phoenix, Tucson, Albuquerque, and El Paso have experienced rapid and exponential growth over the past 50 years. The

Water is the defining issue in determining the development and growth of human populations of the Southwest. The cities of Las Vegas, Phoenix, Tucson, Albuquerque, and El Paso have experienced rapid and exponential growth over the past 50 years. The outlook for having access to sustainable sources of water to support this growth is not promising due to water demand and supply deficits. Regional water projects have harnessed the Colorado and Rio Grande rivers to maximize the utility of the water for human consumption and environmental laws have been adopted to regulate the beneficial use of this water, but it still is not enough to create sustainable future for rapidly growing southwest cities. Future growth in these cities will depend on finding new sources of water and creative measures to maximize the utility of existing water resources. The challenge for southwest cities is to establish policies, procedures, and projects that maximizes the use of water and promotes conservation from all areas of municipal users. All cities are faced with the same challenges, but have different options for how they prioritize their water resources. The principal means of sustainable water management include recovery, recharge, reuse, and increasing the efficiency of water delivery. Other strategies that have been adopted include harvesting of rainwater, building codes that promote efficient water use, tiered water rates, turf removal programs, residential water auditing, and native plant promotion. Creating a sustainable future for the southwest will best be achieved by cities that adopt an integrated approach to managing their water resources including discouraging discretionary uses of water, adoption of building and construction codes for master plans, industrial plants, and residential construction. Additionally, a robust plan for education of the public is essential to create a culture of conservation from a very young age.

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2013

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Photovoltaic capacity additions: the optimal rate of deployment with sensitivity to time-based GHG emissions

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Current policies subsidizing or accelerating deployment of photovoltaics (PV) are typically motivated by claims of environmental benefit, such as the reduction of CO2 emissions generated by the fossil-fuel fired power plants that PV is intended to displace. Existing practice is

Current policies subsidizing or accelerating deployment of photovoltaics (PV) are typically motivated by claims of environmental benefit, such as the reduction of CO2 emissions generated by the fossil-fuel fired power plants that PV is intended to displace. Existing practice is to assess these environmental benefits on a net life-cycle basis, where CO2 benefits occurring during use of the PV panels is found to exceed emissions generated during the PV manufacturing phase including materials extraction and manufacture of the PV panels prior to installation. However, this approach neglects to recognize that the environmental costs of CO2 release during manufacture are incurred early, while environmental benefits accrue later. Thus, where specific policy targets suggest meeting CO2 reduction targets established by a certain date, rapid PV deployment may have counter-intuitive, albeit temporary, undesired consequences. Thus, on a cumulative radiative forcing (CRF) basis, the environmental improvements attributable to PV might be realized much later than is currently understood. This phenomenon is particularly acute when PV manufacture occurs in areas using CO2 intensive energy sources (e.g., coal), but deployment occurs in areas with less CO2 intensive electricity sources (e.g., hydro). This thesis builds a dynamic Cumulative Radiative Forcing (CRF) model to examine the inter-temporal warming impacts of PV deployments in three locations: California, Wyoming and Arizona. The model includes the following factors that impact CRF: PV deployment rate, choice of PV technology, pace of PV technology improvements, and CO2 intensity in the electricity mix at manufacturing and deployment locations. Wyoming and California show the highest and lowest CRF benefits as they have the most and least CO2 intensive grids, respectively. CRF payback times are longer than CO2 payback times in all cases. Thin film, CdTe PV technologies have the lowest manufacturing CO2 emissions and therefore the shortest CRF payback times. This model can inform policies intended to fulfill time-sensitive CO2 mitigation goals while minimizing short term radiative forcing.

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2013

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Model-based design, simulation and automatic code generation for embedded systems and robotic applications

Description

As the complexity of robotic systems and applications grows rapidly, development of high-performance, easy to use, and fully integrated development environments for those systems is inevitable. Model-Based Design (MBD) of dynamic systems using engineering software such as Simulink® from MathWorks®,

As the complexity of robotic systems and applications grows rapidly, development of high-performance, easy to use, and fully integrated development environments for those systems is inevitable. Model-Based Design (MBD) of dynamic systems using engineering software such as Simulink® from MathWorks®, SciCos from Metalau team and SystemModeler® from Wolfram® is quite popular nowadays. They provide tools for modeling, simulation, verification and in some cases automatic code generation for desktop applications, embedded systems and robots. For real-world implementation of models on the actual hardware, those models should be converted into compilable machine code either manually or automatically. Due to the complexity of robotic systems, manual code translation from model to code is not a feasible optimal solution so we need to move towards automated code generation for such systems. MathWorks® offers code generation facilities called Coder® products for this purpose. However in order to fully exploit the power of model-based design and code generation tools for robotic applications, we need to enhance those software systems by adding and modifying toolboxes, files and other artifacts as well as developing guidelines and procedures. In this thesis, an effort has been made to propose a guideline as well as a Simulink® library, StateFlow® interface API and a C/C++ interface API to complete this toolchain for NAO humanoid robots. Thus the model of the hierarchical control architecture can be easily and properly converted to code and built for implementation.

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2013