Indiana University-Purdue University Indianapolis (IUPUI) / Think tanks are generally described as nonprofit institutions made up of experts who achieve change by offering policy prescriptions to lawmakers and by strategically marketing their ideas in the media. They have been part of the American political landscape since the turn of the 20th century, and there are now hundreds of such organizations across the country. This study was directed to state-based groups on the conservative side of the political spectrum that produce policy research in support of their political philosophy of a limited role for government, free enterprise in the marketplace, and greater individual liberty. The purpose was to examine the effectiveness of state-level, free-market think tanks, using some of the same criteria that have been applied to national think tanks; evaluate their use of nonprofit networks and the types of social capital they generate; and provide new insights into this relationship.

Liquid Storage Tanks (LSTs) are essential infrastructure systems that are used in various municipal and industrial settings. They play a critical role in storing and transporting liquids such as drinking water, oil, and gas that are used in daily life. Failure of these structures due to their poor seismic performance can have devastating consequences including the release of the stored liquid and damage to the surrounding area with potentially irreversible environmental impacts. In addition, the damage caused to the tank structure can be extensive, resulting in significant financial losses. Furthermore, the disruption of services provided by the tank such as water supply, oil and gas storage can be considerable. It is therefore crucial to study the seismic behaviour of these structures and ensure their safety and reliability to minimize the potential damages. The aim of this study is to investigate the behavior of LSTs in terms of the contained liquid, the tank’s structure, and its supports when subjected to seismic excitations. To obtain accurate results, different numerical techniques are applied in different phases of the study, including the Finite Volume Method (FVM), Finite Elements Method (FEM), Volume of Fluids (VoF) method, and Smoothed Particles Hydrodynamic (SPH) method. These techniques allow for a detailed analysis of the behavior of the tank and its supports during seismic excitation, providing a comprehensive understanding of the performance of LSTs during earthquakes. In order to examine the reliability and accuracy of the numerical model, the first part of the study includes the validation of the developed numerical model through comparison of the model and experimental results. The validated numerical model is then used to obtain the hydrodynamic pressures at different locations on the roof of tanks subjected to base excitations. The effect of liquid impact and hydrodynamic pressures on the roof of LSTs can be significant, however, limited studies have been completed on this issue. In the second part of the study, Artificial Intelligence (AI) techniques such as Genetic Programming are used to formulate these pressure values so that the maximum pressure can be obtained using the tank characteristics such as size and fill depth by the relationship obtained based on the AI approach. In the third part of the study, the supporting structures of LSTs subjected to base excitations are analyzed, and their shear forces are extracted and compared with the National Building Code of Canada (NBC 2020) in order to evaluate the reliability of the code and discuss possible improvements. The results of this study can be used to evaluate and make improvements in standards and guidelines for the seismic design of LSTs, which can help ensure the safety and reliability of these crucial infrastructures during seismic events.

Polymeric materials are popular in civil infrastructure due to their durability, strength, and resistance to corrosion and environmental degradation. However, the long-term performance of such materials in civil infrastructure is still being researched and investigated. This thesis will focus on the long-term performance of two civil infrastructure applications: 1) high-density polyethylene (HDPE) above-ground storage tanks (AST) and 2) silicone and self-healing polymeric concrete sealants. HDPE is a strong and durable plastic material that is commonly used to store a wide range of liquids ASTs. Currently, there are no established protocols for carrying out non-destructive testing (NDT) and assessment of HDPE ASTs for regular inspections, so this study investigated the viability of using infrared thermography (IRT) and ultrasonic testing (UT) for routine inspection. The study discovered that environmental parameters, such as temperature, wind, and humidity, can affect IRT accuracy, and that a proper heating-cooling cycle can aid in defect detection. Concrete joints in pavement systems are often susceptible to deterioration. They are engineered cracks that enable concrete slabs to expand and contract in response to temperature. They serve the dual purpose of preventing water infiltration and improving ride quality, while extending the pavement's service life. Bridge joints, in particular, are susceptible to water and liquid penetration, which can result in extensive damage over time. By applying sealants to these connections, concrete structures can be protected from such damage, thereby extending their service life. Consequently, a better comprehension of sealant performance and additional research are required to develop effective solutions to address these issues and ensure the safety and longevity of concrete structures prone to cracking. In this study, samples of the two commercial silicone joint sealants were sandwiched between Portland cement mortar specimens and tested using a specially designed fixture to imitate the fatigue performance of the joint under simulated field conditions. The results of the study indicated that the fatigue life of the two silicone sealants were different, with Sealant 2 showed better performance than Sealant 1. Both sealants exhibited adhesive failure initiating debonding along the weak interface of cement mortar cube and joint sealant. The results of commercial sealants are then compared with self-healing polysulfide sealants. This indicates that the performance of sealants can vary, and additional research may be required to develop effective solutions to address these issues. / Master of Science / Polymeric materials are widely utilized in construction due to their durability, strength, and resistance to corrosion and environmental degradation. However, the long-term performance of these materials in civil infrastructure is still under investigation. This thesis specifically examines the long-term performance of two civil infrastructure applications: 1) high-density polyethylene (HDPE) above-ground storage tanks (ASTs) and 2) silicone and self-healing polymeric concrete sealants. HDPE is a robust and durable plastic material commonly employed for storing various liquids in ASTs. Currently, there are no established protocols for conducting non-destructive testing (NDT) and assessment of HDPE ASTs during regular inspections. Therefore, this study investigates the viability of utilizing infrared thermography (IRT) and ultrasonic testing (UT) for routine inspections. The findings reveal that environmental factors such as temperature, wind, and humidity can impact the accuracy of IRT, and implementing a proper heating-cooling cycle can help in detecting such defects inside the tank structure. Concrete joints in pavement systems are susceptible to deterioration. These engineered cracks allow concrete slabs to expand and contract in response to temperature changes, while preventing water infiltration and enhancing ride quality, thus prolonging the pavement's service life. Bridge joints, in particular, are prone to water and liquid penetration, leading to extensive damage over time. Applying sealants to these connections safeguards concrete structures, extending their service life. Consequently, understanding sealant performance and conducting further research are crucial for developing effective solutions to address these issues and ensure the safety and durability of concrete structures prone to cracking. This study involves testing two commercially available silicone joint sealants by sandwiching them between Portland cement mortar specimens. A specially designed fixture is employed to simulate the fatigue performance of joints under field-like conditions. The performance of commercial sealants was also compared with self-healing polysulfide sealants. These findings highlight the variability in sealant performance, emphasizing the need for additional research to develop effective solutions.

The Arctic is a region which has been historically and is contemporary important for Russia. The Arctic is a matter of concern not only for the states bordering it but has also garnered attention from China. It demonstrated its interest by releasing its policy on the region for the first time in 2018. This thesis examines Russia's perception of China in the Arctic from 2018 to 2023. To realise this goal, the thesis will analyse the official Russian government's stance and narrative with experts' opinions in Russian think tanks and compare the two. Furthermore, mapping out how the views have evolved and whether they differ between think tank experts and the official government approach. A mixed method content analysis is employed to analyse the change over time and make the comparison fruitfully. A coding scheme is formed by utilising a theoretical framework grounded in extant studies on the relations between Russia and the Arctic. The findings suggest an absence of threat in policy documents and other publications, implying that China is not perceived as a threat in the Arctic. In addition, the think tank views follow and reinforce views expressed in policy documents.

This thesis aims to investigate how the major U.S. and UK think tanks perceive and convey the military prowess of Russia and Ukraine following the Russia-Ukraine war from February 2022 to October 2023. The study uses poststructuralism and discourse analysis to examine blogs and reports from the major U.S. and U.K. think tanks to identify their perceptions and attitudes. In scrutinizing their perceptions, this paper has limited itself to examining three dimensions of military prowess those being; morale and leadership, offensive capabilities, and the logistics and equipment. The relevance of recognizing how the major U.S. and UK think tanks perceive and convey the military prowess of Russia and Ukraine from a poststructuralist lens is due to the think tanks' influence in shaping domestic and foreign policymaking, as well as public debate. Something which could impact not only the trajectory of the Russia-Ukraine war, but also have national, regional, and global repercussions. The major findings of this thesis show that although the major U.S. and U.K. think tanks, which say they are non-biased actors, still prescribe and convey negative and subjective undertones and themes. Portraying for example Russia as having “incompetent” leadership and moral stature with its material advantage being its “only” cause for “success”. Whereas, for example, Ukraine's leadership and morale are praised for being the driving force for the “success” they have “enjoyed”. Whilst simultaneously being reluctant about its future, as it is described as the “only” factor for its “success”. Based on the findings, the thesis suggests future research on the issue in other domains is needed due to its relevancy in this and other fields.

The objective of this research was to develop a test methodology for the evaluation of materials for possible use in cryogenic composite overwrapped pressure vessels (COPVs). This paper investigates various micromechanical and macromechanical techniques to test the interaction between fibers and resins. Uniaxial tension testing was performed at ambient and cryogenic temperatures on neat resin samples, straight-sided composite specimens, and NOL ring specimens. COPVs were constructed and burst tested to provide a performance comparison. Results show resins suitable for use at cryogenic conditions display a LN2 temperature elongation to failure greater than 2% and an ambient temperature elastic modulus less than 35 MPa. NOL rings were determined to be the preferred composite test method rather than straight-sided specimens. Mechanical performance of the NOL rings compares well with actual COPV performance.

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