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- Creators: Mechanical and Aerospace Engineering Program
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Description
On-officer video camera (OVC) technology in the field of policing is developing at a rapid pace. Large agencies are beginning to adopt the technology on a limited basis, and a number of cities across the United States have required their police departments to adopt the technology for all first responders. Researchers have just begun to examine its effects on citizen complaints, officers' attitudes, and street-level behavior. To date, however, there is no research examining how departmental policy and assignment of officers to a camera program affect officer behavior and opinions of the cameras. Policy and assignment have the potential to impact how officers react to the technology and can affect their interactions with citizens on a daily basis. This study measures camera activations by line officers in the Mesa Police Department during police-citizen encounters over a ten-month period. Data from 1,675 police-citizen contacts involving camera officers were subject to analysis. Net of controls (i.e., the nature of the crime incident, how it was initiated, officer shift, assignment, presence of bystanders and backup, and other situational factors), the bivariate and multivariate logistic regression analyses were used to examine how departmental policy (mandatory versus discretionary activation policy) and officer assignment (voluntary versus mandatory assignment) affected willingness to activate the cameras, as well as officer and citizen behavior during field contacts.
ContributorsRoy, Allyson (Author) / Ready, Justin (Thesis advisor) / Telep, Cody (Committee member) / Fox, Kate (Committee member) / Arizona State University (Publisher)
Created2014
Description
The purpose of this study was to investigate the relationship between the structures of nonprofit victim service organizations and organizational effectiveness. Past research has rarely considered the structures of nonprofit institutions, and thus there is a lack of understanding regarding how nonprofit service organizations function, and whether not traditional concepts of effectiveness can accurately describe organizational success. Thus, there is an opportunity for further exploration regarding how this structural change impacted organizational effectiveness. This study used mixed-methodology including surveys (N=16), interviews (N=17), and comparative case studies (N=5) to examine nonprofit organizational structures and effectiveness in efforts to answer questions regarding the reality of hybrid nonprofit structures, the characteristics of these hybrid structures, and the presentation of organizational effectiveness in nonprofit service organizations. The findings revealed that a) hybrid structures are overwhelmingly the style of service nonprofits, b) externally bureaucratic structures and collective internal structures are combined to form these hybrid organizations, and c) traditional measures of organizational effectiveness as well as characteristics unique to hybrid structures are influential in determining effectiveness in nonprofit service organizations. Future research should consider what factors influence the collaboration of nonprofit service organizations and criminal justice institutions in order to best support crime victims.
ContributorsVerhagen, Megan (Author) / Holtfreter, Kristy (Thesis advisor) / Fox, Kate (Committee member) / Messing, Jill (Committee member) / Arizona State University (Publisher)
Created2018
Description
The purpose of this study was to observe the effectiveness of the phenylalanyl arginine β-naphthylamide dihydrochloride inhibitor and Tween 20 when combined with an antibiotic against Escherichia. coli. As antibiotic resistance becomes more and more prevalent it is necessary to think outside the box and do more than just increase the dosage of currently prescribed antibiotics. This study attempted to combat two forms of antibiotic resistance. The first is the AcrAB efflux pump which is able to pump antibiotics out of the cell. The second is the biofilms that E. coli can form. By using an inhibitor, the pump should be unable to rid itself of an antibiotic. On the other hand, using Tween allows for biofilm formation to either be disrupted or for the biofilm to be dissolved. By combining these two chemicals with an antibiotic that the efflux pump is known to expel, low concentrations of each chemical should result in an equivalent or greater effect on bacteria compared to any one chemical in higher concentrations. To test this hypothesis a 96 well plate BEC screen test was performed. A range of antibiotics were used at various concentrations and with varying concentrations of both Tween and the inhibitor to find a starting point. Following this, Erythromycin and Ciprofloxacin were picked as the best candidates and the optimum range of the antibiotic, Tween, and inhibitor were established. Finally, all three chemicals were combined to observe the effects they had together as opposed to individually or paired together. From the results of this experiment several conclusions were made. First, the inhibitor did in fact increase the effectiveness of the antibiotic as less antibiotic was needed if the inhibitor was present. Second, Tween showed an ability to prevent recovery in the MBEC reading, showing that it has the ability to disrupt or dissolve biofilms. However, Tween also showed a noticeable decrease in effectiveness in the overall treatment. This negative interaction was unable to be compensated for when using the inhibitor and so the hypothesis was proven false as combining the three chemicals led to a less effective treatment method.
ContributorsPetrovich Flynn, Chandler James (Author) / Misra, Rajeev (Thesis director) / Bean, Heather (Committee member) / Perkins, Kim (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
An in-depth analysis on the effects vortex generators cause to the boundary layer separation that occurs when an internal flow passes through a diffuser is presented. By understanding the effects vortex generators demonstrate on the boundary layer, they can be utilized to improve the performance and efficiencies of diffusers and other internal flow applications. An experiment was constructed to acquire physical data that could assess the change in performance of the diffusers once vortex generators were applied. The experiment consisted of pushing air through rectangular diffusers with half angles of 10, 20, and 30 degrees. A velocity distribution model was created for each diffuser without the application of vortex generators before modeling the velocity distribution with the application of vortex generators. This allowed the two results to be directly compared to one another and the improvements to be quantified. This was completed by using the velocity distribution model to find the partial mass flow rate through the outer portion of the diffuser's cross-sectional area. The analysis concluded that the vortex generators noticeably increased the performance of the diffusers. This was best seen in the performance of the 30-degree diffuser. Initially the diffuser experienced airflow velocities near zero towards the edges. This led to 0.18% of the mass flow rate occurring in the outer one-fourth portion of the cross-sectional area. With the application of vortex generators, this percentage increased to 5.7%. The 20-degree diffuser improved from 2.5% to 7.9% of the total mass flow rate in the outer portion and the 10-degree diffuser improved from 11.9% to 19.2%. These results demonstrate an increase in performance by the addition of vortex generators while allowing the possibility for further investigation on improvement through the design and configuration of these vortex generators.
ContributorsSanchez, Zachary Daniel (Author) / Takahashi, Timothy (Thesis director) / Herrmann, Marcus (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
The objective of this project was to design an electrically driven centrifugal pump for the Daedalus Astronautics @ASU hybrid rocket engine (HRE). The pump design was purposefully simplified due to time, fabrication, calculation, and capability constraints, which resulted in a lower fidelity design, with the option to be improved later. The impeller, shroud, volute, shaft, motor, and ESC were the main focuses of the pump assembly, but the seals, bearings, lubrication methods, and flow path connections were considered as elements which would require future attention. The resulting pump design is intended to be used on the Daedalus Astronautics HRE test cart for design verification. In the future, trade studies and more detailed analyses should and will be performed before this pump is integrated into the Daedalus Astronautics flight-ready HRE.
ContributorsShillingburg, Ryan Carl (Author) / White, Daniel (Thesis director) / Brunacini, Lauren (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Human habitation of other planets requires both cost-effective transportation and low time-of-flight for human passengers and critical supplies. The current methods for interplanetary orbital transfers, such as the Hohmann transfer, require either expensive, high fuel maneuvers or extended space travel. However, by utilizing the high velocities of a super-geosynchronous space elevator, spacecraft released from an apex anchor could achieve interplanetary transfers with minimal Delta V fuel and time of flight requirements. By using Lambert’s Problem and Free Release propagation to determine the minimal fuel transfer from a terrestrial space elevator to Mars under a variety of initial conditions and time-of-flight constraints, this paper demonstrates that the use of a space elevator release can address both needs by dramatically reducing the time-of-flight and the fuel budget.
ContributorsTorla, James (Author) / Peet, Matthew (Thesis director) / Swan, Peter (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
This thesis evaluates the viability of an original design for a cost-effective wheel-mounted dynamometer for road vehicles. The goal is to show whether or not a device that generates torque and horsepower curves by processing accelerometer data collected at the edge of a wheel can yield results that are comparable to results obtained using a conventional chassis dynamometer. Torque curves were generated via the experimental method under a variety of circumstances and also obtained professionally by a precision engine testing company. Metrics were created to measure the precision of the experimental device's ability to consistently generate torque curves and also to compare the similarity of these curves to the professionally obtained torque curves. The results revealed that although the test device does not quite provide the same level of precision as the professional chassis dynamometer, it does create torque curves that closely resemble the chassis dynamometer torque curves and exhibit a consistency between trials comparable to the professional results, even on rough road surfaces. The results suggest that the test device provides enough accuracy and precision to satisfy the needs of most consumers interested in measuring their vehicle's engine performance but probably lacks the level of accuracy and precision needed to appeal to professionals.
ContributorsKing, Michael (Author) / Ren, Yi (Thesis director) / Spanias, Andreas (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This research project will test the structural properties of a 3D printed origami inspired structure and compare them with a standard honeycomb structure. The models have equal face areas, model heights, and overall volume but wall thicknesses will be different. Stress-deformation curves were developed from static loading testing. The area under these curves was used to calculate the toughness of the structures. These curves were analyzed to see which structures take more load and which deform more before fracture. Furthermore, graphs of the Stress-Strain plots were produced. Using 3-D printed parts in tough resin printed with a Stereolithography (SLA) printer, the origami inspired structure withstood a larger load, produced a larger toughness and deformed more before failure than the equivalent honeycomb structure.
ContributorsMcGregor, Alexander (Author) / Jiang, Hanqing (Thesis director) / Kingsbury, Dallas (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This paper describes the research done to quantify the relationship between external air temperature and energy consumption and internal air temperature and energy consumption. The study was conducted on a LEED Gold certified building, College Avenue Commons, located on Arizona State University's Tempe campus. It includes information on the background of previous studies in the area, some that agree with the research hypotheses and some that take a different path. Real-time data was collected hourly for energy consumption and external air temperature. Intermittent internal air temperature was collected by undergraduate researcher, Charles Banke. Regression analysis was used to prove two research hypotheses. The authors found no correlation between external air temperature and energy consumption, nor did they find a relationship between internal air temperature and energy consumption. This paper also includes recommendations for future work to improve the study.
ContributorsBanke, Charles Michael (Author) / Chong, Oswald (Thesis director) / Parrish, Kristen (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This paper explores the consequences of cleaning rescue ropes with common disinfectants and cleansers in order to assess their usability in cleaning ropes contaminated with blood borne pathogens. Using a modified version of an industry-standard testing procedure and in-depth statistical analysis, it characterizes the effect each chemical has on the mechanical properties of the rope. The experiment measured the strength and elastic properties of rope core fibers soaked in different chemicals and at different concentration levels. The data show that certain common solutions for cleaning equipment are, in fact, damaging to the equipment and thus dangerous to the users. Even products marketed for climbing ropes were found to be potentially hazardous. The results also demonstrate a curious phenomenon occurring within the washing process that causes a shift in the elastic properties of the fibers, prompting additional research. Further work is needed to expand the breadth and depth of these results and to make effective recommendations to the rope industry and rescue professionals regarding rope care and maintenance.
ContributorsDenike, Andrew Nicholas (Author) / Middleton, James (Thesis director) / Liao, Yabin (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05