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Surface Mechanical Attrition Treatment (SMAT) of 7075 Aluminum Alloy to Induce a Protective Corrosion Resistant Layer

Description

This paper investigates Surface Mechanical Attrition Treatment (SMAT) and the influence of treatment temperature and initial sample surface finish on the corrosion resistance of 7075-T651 aluminum alloy. Ambient SMAT was performed on AA7075 samples polished to 80-grit initial surface roughness.

This paper investigates Surface Mechanical Attrition Treatment (SMAT) and the influence of treatment temperature and initial sample surface finish on the corrosion resistance of 7075-T651 aluminum alloy. Ambient SMAT was performed on AA7075 samples polished to 80-grit initial surface roughness. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were used to characterize the corrosion behavior of samples before and after SMAT. Electrochemical tests indicated an improved corrosion resistance after application of SMAT process. The observed improvements in corrosion properties are potentially due to microstructural changes in the material surface induced by SMAT which encouraged the formation of a passive oxide layer. Further testing and research are required to understand the corrosion related effects of cryogenic SMAT and initial-surface finish as the COVID-19 pandemic inhibited experimentation plans.

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2020-05

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Developing Inventory Control and Build Management Software for Spacecraft Engineering

Description

Engineering an object means engineering the process that creates the object. Today, software can make the task of tracking these processes robust and straightforward. When engineering requirements are strict and strenuous, software custom-built for such processes can prove essential. The

Engineering an object means engineering the process that creates the object. Today, software can make the task of tracking these processes robust and straightforward. When engineering requirements are strict and strenuous, software custom-built for such processes can prove essential. The work for this project was developing ICDB, an inventory control and build management system created for spacecraft engineers at ASU to record each step of their engineering processes. In-house development means ICDB is more precisely designed around its users' functionality and cost requirements than most off-the-shelf commercial offerings. By placing a complex relational database behind an intuitive web application, ICDB enables organizations and their users to create and store parts libraries, assembly designs, purchasing and location records for inventory items, and more.

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2018-05

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Evaluation of an Original Design for a Cost-Effective Wheel-Mounted Dynamometer for Road Vehicles

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

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.

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2018-05

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In situ SEM Testing for Fatigue Crack Growth: Mechanical Investigation of Titanium

Description

Widespread knowledge of fracture mechanics is mostly based on previous models that generalize crack growth in materials over several loading cycles. The objective of this project is to characterize crack growth that occurs in titanium alloys, specifically Grade 5 Ti-6Al-4V,

Widespread knowledge of fracture mechanics is mostly based on previous models that generalize crack growth in materials over several loading cycles. The objective of this project is to characterize crack growth that occurs in titanium alloys, specifically Grade 5 Ti-6Al-4V, at the sub-cycle scale, or within a single loading cycle. Using scanning electron microscopy (SEM), imaging analysis is performed to observe crack behavior at ten loading steps throughout the loading and unloading paths. Analysis involves measuring the incremental crack growth and crack tip opening displacement (CTOD) of specimens at loading ratios of 0.1, 0.3, and 0.5. This report defines the relationship between crack growth and the stress intensity factor, K, of the specimens, as well as the relationship between the R-ratio and stress opening level. The crack closure phenomena and effect of microcracks are discussed as they influence the crack growth behavior. This method has previously been used to characterize crack growth in Al 7075-T6. The results for Ti-6Al-4V are compared to these previous findings in order to strengthen conclusions about crack growth behavior.

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2018-05

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An Examination of the Impact of Support Design on 316 Stainless Steel Supports

Description

The removal of support material from metal 3D printed objects is a laborious necessity for the post-processing of powder bed fusion printing (PBF). Supports are typically mechanically removed by machining techniques. Sacrificial supports are necessary in PBF printing to relieve

The removal of support material from metal 3D printed objects is a laborious necessity for the post-processing of powder bed fusion printing (PBF). Supports are typically mechanically removed by machining techniques. Sacrificial supports are necessary in PBF printing to relieve thermal stresses and support overhanging parts often resulting in the inclusion of supports in regions of the part that are not easily accessed by mechanical removal methods. Recent innovations in PBF support removal include dissolvable metal supports through an electrochemical etching process. Dissolvable PBF supports have the potential to significantly reduce the costs and time associated with traditional support removal. However, the speed and effectiveness of this approach is inhibited by numerous factors such as support geometry and metal powder entrapment within supports. To fully realize this innovative approach, it is necessary to model and understand the design parameters necessary to optimize support structures applicable to an electrochemical etching process. The objective of this study was to evaluate the impact of block additive manufacturing support parameters on key process outcomes of the dissolution of 316 stainless steel support structures. The parameters investigated included hatch spacing and perforation, and the outcomes of interests included time required for completion, surface roughness, and effectiveness of the etching process. Electrical current was also evaluated as an indicator of process completion. Analysis of the electrical current throughout the etching process showed that the dissolution is diffusion limited to varying degrees, and is dependent on support structure parameters. Activation and passivation behavior was observed during current leveling, and appeared to be more pronounced in non-perforated samples with less dense hatch spacing. The correlation between electrical current and completion of the etching process was unclear, as the support structures became mechanically removable well before the current leveled. The etching process was shown to improve surface finish on unsupported surfaces, but support was shown to negatively impact surface finish. Tighter hatch spacing was shown to correlate to larger variation in surface finish, due to ridges left behind by the support structures. In future studies, it is recommended current be more closely correlated to process completion and more roughness data be collected to identify a trend between hatch spacing and surface roughness.

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Date Created
2018-05

Behavior Trees + Finite State Machines: A Hybrid Game AI Framework

Description

One of the core components of many video games is their artificial intelligence. Through AI, a game can tell stories, generate challenges, and create encounters for the player to overcome. Even though AI has continued to advance through the implementation

One of the core components of many video games is their artificial intelligence. Through AI, a game can tell stories, generate challenges, and create encounters for the player to overcome. Even though AI has continued to advance through the implementation of neural networks and machine learning, game AI tends to implement a series of states or decisions instead to give the illusion of intelligence. Despite this limitation, games can still generate a wide range of experiences for the player. The Hybrid Game AI Framework is an AI system that combines the benefits of two commonly used approaches to developing game AI: Behavior Trees and Finite State Machines. Developed in the Unity Game Engine and the C# programming language, this AI Framework represents the research that went into studying modern approaches to game AI and my own attempt at implementing the techniques learned. Object-oriented programming concepts such as inheritance, abstraction, and low coupling are utilized with the intent to create game AI that's easy to implement and expand upon. The final goal was to create a flexible yet structured AI data structure while also minimizing drawbacks by combining Behavior Trees and Finite State Machines.

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2018-05

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Developing a Curriculum to Prepare Software Engineers for the Technical Interview Process

Description

ASU’s Software Engineering (SER) program adequately prepares students for what happens after they become a developer, but there is no standard for preparing students to secure a job post-graduation in the first place. This project creates and executes a supplemental

ASU’s Software Engineering (SER) program adequately prepares students for what happens after they become a developer, but there is no standard for preparing students to secure a job post-graduation in the first place. This project creates and executes a supplemental curriculum to prepare students for the technical interview process. The trial run of the curriculum was received positively by study participants, who experienced an increase in confidence over the duration of the workshop.

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Date Created
2019-05

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Why Students in Computer Science Courses Cheat?

Description

The goal of this study is to equip administrators and instructors with a deeper understanding of the apparent cheating problem in Computer Science courses, with proposed solutions to lower academic dishonesty from the students’ perspective.

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Date Created
2019-05

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Using Machine Learning to Predict the NBA

Description

Machine learning is one of the fastest growing fields and it has applications in almost any industry. Predicting sports games is an obvious use case for machine learning, data is relatively easy to collect, generally complete data is available, and

Machine learning is one of the fastest growing fields and it has applications in almost any industry. Predicting sports games is an obvious use case for machine learning, data is relatively easy to collect, generally complete data is available, and outcomes are easily measurable. Predicting the outcomes of sports events may also be easily profitable, predictions can be taken to a sportsbook and wagered on. A successful prediction model could easily turn a profit. The goal of this project was to build a model using machine learning to predict the outcomes of NBA games.
In order to train the model, data was collected from the NBA statistics website. The model was trained on games dating from the 2010 NBA season through the 2017 NBA season. Three separate models were built, predicting the winner, predicting the total points, and finally predicting the margin of victory for a team. These models learned on 80 percent of the data and validated on the other 20 percent. These models were trained for 40 epochs with a batch size of 15.
The model for predicting the winner achieved an accuracy of 65.61 percent, just slightly below the accuracy of other experts in the field of predicting the NBA. The model for predicting total points performed decently as well, it could beat Las Vegas’ prediction 50.04 percent of the time. The model for predicting margin of victory also did well, it beat Las Vegas 50.58 percent of the time.

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2019-05

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Empowering Women in Zambia through Computational Thinking Curriculum

Description

The nonprofit organization, I Am Zambia, works to give supplemental education to young women in Lusaka. I Am Zambia is creating sustainable change by educating these females, who can then lift their families and communities out of poverty. The ultimate

The nonprofit organization, I Am Zambia, works to give supplemental education to young women in Lusaka. I Am Zambia is creating sustainable change by educating these females, who can then lift their families and communities out of poverty. The ultimate goal of this thesis was to explore and implement high level systematic problem solving through basic and specialized computational thinking curriculum at I Am Zambia in order to give these women an even larger stepping stool into a successful future.

To do this, a 4-week long pilot curriculum was created, implemented, and tested through an optional class at I Am Zambia, available to women who had already graduated from the year-long I Am Zambia Academy program. A total of 18 women ages 18-24 chose to enroll in the course. There were a total of 10 lessons, taught over 20 class period. These lessons covered four main computational thinking frameworks: introduction to computational thinking, algorithmic thinking, pseudocode, and debugging. Knowledge retention was tested through the use of a CS educational tool, QuizIt, created by the CSI Lab of School of Computing, Informatics and Decision Systems Engineering at Arizona State University. Furthermore, pre and post tests were given to assess the successfulness of the curriculum in teaching students the aforementioned concepts. 14 of the 18 students successfully completed the pre and post test.

Limitations of this study and suggestions for how to improve this curriculum in order to extend it into a year long course are also presented at the conclusion of this paper.

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2019-05