Matching Items (3)
Description
Needle steering is an extension of manually inserted needles that allows for maneuverability within the body in order to avoid anatomical obstacles and correct for undesired placement errors. Research into needle steering predominantly exploits interaction forces between a beveled tip and the medium, controlling the direction of forces by applying rotations at the base of the needle shaft in order to steer. These systems are either manually or robotically advanced, but have not achieved clinical relevance due to a multitude of limitations including compression effects in the shaft that cause undesired tissue slicing, torsional friction forces and deflection at tissue boundaries that create control difficulties, and a physical design that inherently restricts the workspace. While most improvements into these systems attempt to innovate the needle design or create tissue models to better understand interaction forces, this paper discusses a promising alternative: magnetic needle steering. Chapter 2 discusses an electromagnetic needle steering system that overcomes all aforementioned issues with traditional steering. The electromagnetic system advances the needle entirely magnetically so it does not encounter any compression or torsion effects, it can steer across tissue-interfaces at various angles of attack (90, 45, 22.5°) with root-mean-square error (RMSE) of 1.2 mm, achieve various radii of curvature as low as 10.2 mm with RMSE of 1.4 mm, and steer along complex 3D paths with RMSE as low as 0.4 mm. Although these results do effectively prove the viability of magnetic steering, the electromagnetic system is limited by a weak magnetic field and small 33mm cubic workspace. In order to overcome these limitations, the use of permanent magnets, which can achieve magnetic forces an order of magnitude larger than similarly sized electromagnetics, is investigated. The needle will be steered toward a permanent magnet configuration that is controlled by a 6 degree-of-freedom robotic manipulator. Three magnet configurations were investigated, two novel ideas that attempt to create local maximum points that stabilize the needle relative to the configuration, and one that pulls the needle toward a single magnet. Ultimately, the last design was found to be most viable to demonstrate the effectiveness of magnetic needle steering.
ContributorsPetras, Alex (Author) / Marvi, Hamidreza (Thesis advisor) / Yong, Sze Z. (Committee member) / Ross, Heather M. (Committee member) / Arizona State University (Publisher)
Created2020
Description
ABSTRACT
The purpose of this thesis is to identify the key determinants of changes in the public’s perception and the historical and legal context for the current laws that govern the Right to Die in America. At its essence, the Right to Die Movement can be summarized in six selected narratives that were performed, told, debated, or reported for the public throughout history. Each of these six stories was presented with the most effective communication technologies available to the narrators in their respective eras.
The thesis includes an original research study assessing the impact of a social media phenomenon on the Right to Die Movement. While the Brittany Maynard Farewell video may not have been solely responsible for the surge of public support for MAID, it certainly captured the sense of autonomy and individual rights Americans believe they have in 2014 and continuing at least through 2019. This belief in autonomy and individual rights influenced the American sense of who owns their bodies and who can control their deaths after they are given terminal diagnoses. The first key narrative introduced Natural Law and the Natural Rights that proceed from this universal law. The second opened up communication about death. The next three demonstrated to Americans what legal rights they had and which were withheld by tradition and law. The last narrative captured and embodied the American sense of autonomy and individual rights that a majority of Americans now feel they possess. The laws and policies that have resulted from the Right to Die Movement both define the boundaries of autonomy and construct an evolving understanding of human freedom.
The purpose of this thesis is to identify the key determinants of changes in the public’s perception and the historical and legal context for the current laws that govern the Right to Die in America. At its essence, the Right to Die Movement can be summarized in six selected narratives that were performed, told, debated, or reported for the public throughout history. Each of these six stories was presented with the most effective communication technologies available to the narrators in their respective eras.
The thesis includes an original research study assessing the impact of a social media phenomenon on the Right to Die Movement. While the Brittany Maynard Farewell video may not have been solely responsible for the surge of public support for MAID, it certainly captured the sense of autonomy and individual rights Americans believe they have in 2014 and continuing at least through 2019. This belief in autonomy and individual rights influenced the American sense of who owns their bodies and who can control their deaths after they are given terminal diagnoses. The first key narrative introduced Natural Law and the Natural Rights that proceed from this universal law. The second opened up communication about death. The next three demonstrated to Americans what legal rights they had and which were withheld by tradition and law. The last narrative captured and embodied the American sense of autonomy and individual rights that a majority of Americans now feel they possess. The laws and policies that have resulted from the Right to Die Movement both define the boundaries of autonomy and construct an evolving understanding of human freedom.
ContributorsGrossman, Jennifer Elizabeth (Author) / Gereboff, Joel (Thesis advisor) / Ross, Heather M. (Committee member) / Bennett, Gaymon (Committee member) / Arizona State University (Publisher)
Created2020
Description
This dissertation focused on the implementation of urine diversion systems in commercial and institutional buildings in the United States with a focus on control of the urea hydrolysis reaction. Urine diversion is the process by which urine is separately collected at the source in order to realize system benefits, including water conservation, nutrient recovery, and pharmaceutical removal. Urine diversion systems depend greatly on the functionality of nonwater urinals and urine diverting toilets, which are needed to collect undiluted urine. However, the urea hydrolysis reaction creates conditions that lead to precipitation in the fixtures due to the increase in pH from 6 to 9 as ammonia and bicarbonate are produced. Chapter 2 and Chapter 3 describes the creation and use of a cyber-physical system (CPS) to monitor and control urea hydrolysis in the urinal testbed. Two control logics were used to control urea hydrolysis in realistic restroom conditions. In the experiments, acid was added to inhibit urea hydrolysis during periods of high and low building occupancy. These results were able to show that acid should be added based on the restroom use in order to efficiently inhibit urea hydrolysis.
Chapter 4 advanced the results from Chapter 3 by testing the acid addition control logics in a real restroom with the urinal-on-wheels. The results showed that adding acid during periods of high building occupancy equated to the least amount of acid added and allowed for urea hydrolysis inhibition. This study also analyzed the bacterial communities of the collected urine and found that acid addition changed the structure of the bacterial communities.
Chapter 5 showed an example of the capabilities of a CPS when implemented in CI buildings. The study used data mining methods to predict chlorine residuals in premise plumbing in a CI green building. The results showed that advance modeling methods were able to model the system better than traditional methods. These results show that CPS technology can be used to illuminate systems and can provide information needed to understand conditions within CI buildings.
ContributorsSaetta, Daniella (Author) / Boyer, Treavor H (Thesis advisor) / Hamilton, Kerry (Committee member) / Ross, Heather M. (Committee member) / Boscovic, Dragan (Committee member) / Arizona State University (Publisher)
Created2021