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- Title
- Ultraviolet photo-chemical degradation of polyethylene terephthalate for use as an alternative recycling method
- Creator
- Smith, Andrew Thomas
- Date
- 2020
- Description
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Consumer plastics are a deeply integrated part of the modern world. Their inherent properties which make them cheap, durable, moldable, and...
Show moreConsumer plastics are a deeply integrated part of the modern world. Their inherent properties which make them cheap, durable, moldable, and versatile have caused plastics to be used in many consumer products available for market. However, these same properties have made them a detriment to local and global environments. plastic has begun accumulating in the world’s waterways and oceans, leading to severe ecological consequences. Polyethylene terephthalate (PET) is one of the most pervasive consumer plastic, and a large contributor to the amount of waste. Because of its prevalence in the market, PET has been the focus of research into its recycling and reuse. However, all methods face issues of profitability due to operation and equipment costs, preventing widespread recycling of plastic waste. This leaves the door open to explore other processes of plastic recycling.In this study, ultraviolet photo-chemical degradation of PET was explored as an alternate route to plastic recycling. Ultraviolet irradiation has long been known to depolymerize PET plastic products, but has not been studied in order to enhance these effects. This method has the potential to reduce operation and equipment costs associated with traditional chemical recycling methods by carrying out depolymerization in the solid state. By harnessing this process, PET could be used to degrade material down to a state usable in in other, higher value products. An irradiation chamber was built as a preliminary prototype. This chamber used light of a specific ultraviolet wavelength determined from the absorbance spectrum of PET samples. This allowed the irradiation to be safer, while still maintaining absorption.Ultraviolet degradation of PET was first examined using infrared, contact angle, and fluorescence analysis, and birefringence observation to analyze the chemical and surface effects of irradiation. The results were used to understand the complex mechanisms behind the photo-chemical degradation process. Results were then discussed alongside similar experiments performed in the literature for a deeper understanding of the underlying mechanism.The molecular weight of exposed bottle samples was evaluated using both viscosity and dynamic light scattering methods. This information is key, as it is the main metric that determines the success of the process. In addition, the ultraviolet absorbance of the sample was analyzed along with the principles of Beer’s law. This yielded quantitative analysis on the effect of thickness of the sample, the degradation rate, and the quantum yield of the process.Finally, building upon the information gathered in the study, two key process modifications are made. Thinner samples are first produced, and receive irradiation on both surfaces. The degradation of the modified process was compared to that of previous results on the basis of molecular weight reduction, reaction rate and quantum yield. Using these results, conclusions were drawn about using ultraviolet photo-chemical degradation as a recycling process.
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- Title
- ENERGY INNOVATIONS IN BUILDINGS AND URBAN FABRICS
- Creator
- Hirematt, Chandrasekharaiah Ashish
- Date
- 2021
- Description
-
In his keynote speech on the "Infrastructures of Integration" at the 5th International LafargeHolcim Forum for Sustainable Construction, Ricky...
Show moreIn his keynote speech on the "Infrastructures of Integration" at the 5th International LafargeHolcim Forum for Sustainable Construction, Ricky Burdett, Professor of Urban Studies at the London School of Economics & Political Science (LSE), said “…you can actually invest in better infrastructure to do things better.” However, the population grows at the rate of almost one billion per decade. With about four fifths of it happening in urban areas, the challenge for sustainability is huge and the key for the future.Urban fabrics are expanding both vertically as well as horizontally to accommodate the population growth. With the scale of expansion happening, challenges such deforestation, resource depletion, habitat destruction, energy production and consumption are some of the major challenges that need to be focused on ecologically. It is also important to note that ecological solutions are very highly dependent on social and economic progress of the society. Energy efficient design is one which does zero or minimal damage to the environment while meeting the energy needs of the society. This thesis will discuss the concept of developing energy efficient designs as well as net zero designs in urban settings. With the help of three projects, this thesis aims to discover the challenges along with the obvious advantages of such designs. The first experiment is to look at the reduction of energy consumption in the city of Chicago with multiple neighborhoods set up in an iron grid. It was observed that taller buildings are much more energy efficient due to the reduction of surface area exposed to the external environment. This observation was used to develop a climate specific energy efficient urban fabric design in the city of Shenzhen. The design of the off-shore tower involves tackling larger issues such as the pandemic while having energy production as a bi-product of the same. Thus, the thesis argues that investment in infrastructure to build a better infrastructure should be done to solve social and economic challenges which will, in turn make it easier to produce energy efficient designs.
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- Title
- Habitat 2022+
- Creator
- Cho, San Lae Lae
- Date
- 2021
- Description
-
Globalization and urbanization have led a vast group of population to shift from rural and suburban areas to urban centers. According to the...
Show moreGlobalization and urbanization have led a vast group of population to shift from rural and suburban areas to urban centers. According to the United Nation’s (UN) projection, around 2.5 billion more people will live in the cities by 2050. For cities to accommodate such a population, cities can grow horizontally or vertically. If cities were to grow horizontally, this population would need to commute majorly by car which has a very high carbon footprint. By building vertically, the population’s commute becomes more efficient if the vertical structure is built as such is a city within a city. Although having existed for 500 years, tall buildings and skyscrapers have been topics of controversy for their excessive use of resources, ignoring environmental and contextual problems. In order to mitigate this sustainability issue, mass timber as a construction material has been recently introduced into the American market. Mass timber is the building material for a carbon neutral future according to Council on Tall Buildings and Urban Habitats (CTBUH). Another means is to grow plants around the buildings meaning they are regrowing greenery back into nature with the hopes to take a step towards mitigating climate change. In addition, with the argument of tall buildings lacking neighborhood-like qualities that for instance, a Chicago block of housing may give, more and more tall buildings around the world have tried to implement the lush spaces onto the building perimeters. These spaces with plants and trees mimicking nature can exist as both indoor and outdoor spaces. While neighborhoods have parks, these spaces or sky gardens will substitute as modified parks for skyscrapers.With psychological benefits tied to spaces linked to nature in high-rises, such spaces should be integrated in all high rise, residential buildings. Today, in addition to Covid pandemic, many people practice working from home. Meanwhile, it is human nature since birth to want to be surrounded by plants and nature, either spending time under a tree or lying on the grass. To mitigate spending excessive amounts of hours indoors, spaces linked to nature have become crucial in providing a sense of peace and reconnecting back to nature. However, currently architecture that has nature integrated, results in spaces only for the wealthy. Furthermore, architecture in the US is so commercially driven with developers aiming for the most cost effective, most efficient and largest floor areas. For nature to be more available to the living spaces of middle class and ideally working class, the city planners and city development authorities need to get involved. For instance, the city could aid by allocating some of the tax collected to build more green architecture. With the tax fund assistance from the city, high quality living of green architecture will become available and much more affordable.Another option to making living more affordable is by implementing co-living. Despite the Covid-19 pandemic, co-living remains relatively high in demand in Chicago according to Chicago Tribune. For the younger generations such as the Millennials and younger, it is predicted that due to the nature of student loan debts, these generations are less likely to be financially well off after graduation. Hence, they are less likely to establish a family as soon as the previous generations, as most people tend to start a family when they feel financially stable.Hence, in this design thesis, a certain prototype will be tested out regarding some of these issues. This is just one option to the issues above and there are many options and other nuances still available to explore.
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