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Description
The transition to lead-free solder in the electronics industry has benefitted the environment in many ways. However, with new materials systems comes new materials issues. During the processing of copper pads, a protective surface treatment is needed to prevent the copper from oxidizing. Characterizing the copper oxidation underneath the surface treatment is challenging but necessary for product reliability and failure analysis. Currently, FIB-SEM, which is time-consuming and expensive, is what is used to understand and analyze the surface treatment-copper oxide(s)-copper system. This project's goals were to determine a characterization methodology that cuts both characterization time and cost in half for characterizing copper oxidation beneath a surface treatment and to determine which protective surface treatment is the best as defined by multiple criterion such as cost, sustainability, and reliability. Two protective surface treatments, organic solderability preservative (OSP) and chromium zincate, were investigated, and multiple characterization techniques were researched. Six techniques were tested, and three were deemed promising. Through our studies, it was determined that the best surface treatment was organic solderability preservative (OSP) and the ideal characterization methodology would be using FIB-SEM to calibrate a QCM model, along with using SERA to confirm the QCM model results. The methodology we propose would result in a 91% reduction in characterization cost and a 92% reduction in characterization time. Future work includes further calibration of the QCM model using more FIB/SEM data points and eventually creating a model for oxide layer thickness as a function of exposure time and processing temperature using QCM as the primary data source. In doing my Capstone project for Intel, a large electronics manufacturing company, I feel it is important to remember the effects of our tools and industry on the environment and to consider the product life cycle in terms other than monetary gain and raw material recycling. To this end I will be discussing how lead is and was used in manufacturing, how it is disposed of, and how this effects the environment including plant, animal, and insect life, as well as ground water contamination. Since the ban was enacted several years ago, I will compare how lead-free alternatives currently in use compare in environmental impact and possibly raise the question of whether we have simply traded one evil for another.
ContributorsBranch Kelly, Marion Zoe (Author) / Adams, James (Thesis director) / Krause, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor)
Created2015-05
Description
Due to the environmental problems caused by global warming, it has become necessary to reduce greenhouse gas emissions across the planet. Biofuels, such as ethanol, have proven to release cleaner emissions when combusted. However, large scale production of these alcohols is uneconomical and inefficient due to limitations in standard separation processes, the most common being distillation. Pervaporation is a novel separation technique that utilizes a specialized membrane to separate multicomponent solutions. In this research project, pervaporation utilizing ZIF-71/PDMS mixed matrix membranes are investigated to see their ability to recover ethanol from an ethanol/aqueous separation. Membranes with varying nanoparticle concentrations were created and their performances were analyzed. While the final results indicate that no correlation exists between nanoparticle weight percentage and selectivity, this technology is still a promising avenue for biofuel production. Future work will be conducted to improve this existing process and enhance membrane selectivity.
ContributorsHoward, Chelsea Elizabeth (Author) / Lind, Mary Laura (Thesis director) / Nielsen, David (Committee member) / Greenlee, Lauren (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor) / Materials Science and Engineering Program (Contributor)
Created2015-05
Description
The objective for Under the Camper Shell was to build a prototype of a full living environment within the confines of a pickup truck bed and camper shell. The total volume available to work with is approximately 85ft3. This full living environment entails functioning systems for essential modern living, providing shelter and spaces for cooking, sleeping, eating, and sanitation. The project proved to be very challenging from the start. First, the livable space is extremely small, being only tall enough for one to sit up straight. The truck and camper shell were both borrowed items, so no modifications were allowed for either, e.g. drilling holes for mounting. The idea was to create a system that could be easily removed, transforming it from a camper to a utility truck. The systems developed for the living environment would be modular and transformative so to accommodate for different necessities when packing. The goal was to create a low-water system with sustainability in mind. Insulating the space was the largest challenge and the most rewarding, using body heat to warm the space and insulate from the elements. Comfort systems were made of high density foam cushions in sections to allow folding and stacking for different functions (sleeping, lounging, and sitting). Sanitation is necessary for healthy living and regular human function. A composting toilet was used for the design, lending to low-water usage and is sustainable over time. Saw dust would be necessary for its function, but upon composting, the unit will generate sufficient amounts of heat to act as a space heater. Showering serves the functions of exfoliation and ridding of bacteria, both of which bath wipes can accomplish, limiting massive volumes of water storage and waste. Storage systems were also designed for modularity. Hooks were installed the length of the bed for hanging or securing items as necessary. Some are available for hanging bags. A cabinetry rail also runs the length of the bed to allow movement of hard storage to accommodate different scenarios. The cooking method is called "sous-vide", a method of cooking food in air-tight bags submerged in hot water. The water is reusable for cooking and no dishes are necessary for serving. Overall, the prototype fulfilled its function as a full living environment with few improvements necessary for future use.
ContributorsLimsirichai, Pimwadee (Author) / Foy, Joseph (Thesis director) / Parrish, Kristen (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor) / School of Sustainability (Contributor)
Created2014-12
Description
Perovskite films are the future of solar cell technology as they are not only low cost to produce and lightweight but also have a 26% conversion efficiency. This is extremely close to the standard silicon solar cell. The key challenge limiting the commercialization potential of these films is their fragility and durability to outdoors conditions. This project investigates the mechanical and material properties of these perovskite materials in order to understand their future manufacturing capabilities. Through the use of a spin coater, blade coater, and a double cantilever beam testing set up, the fracture energy (or toughness), Gc, of Perovskite films is determined. Understanding the properties of these films can help manufacturers determine how to best make durable films that can be used in everyday energy generation. Furthermore, this study offers strategies to improve the fracture energy of these films by adding polymers and food-additive starches to the recipe. The findings collected in this project present a technique to study the mechanical properties of perovskite-based solar technology and films and further aid the technology to become commercially viable.
ContributorsBakshi, Kayshavi (Author) / Rolston, Nicholas (Thesis director) / Li, Muzhi (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor) / School of International Letters and Cultures (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2023-12
Description
Hairlike structures throughout nature, such as those found in different families of bees, specialize in picking up various sizes of pollen and have adapted structures to increase adhesion and capture. These structures vary widely in size, spacing, and geometry to optimize adhesion through the use of mechanical interlocking as well as Van der Waals forces. Beyond bees, hairlike structures can be found in geckos and arachnids, allowing both to stick to smooth surfaces. These hairlike structures can be used for a variety of applications such as drug delivery, surface adhesion, filtration and separation. This project seeks to determine the efficacy of 3D printed hairlike structures for particle entrapment and understand the underlying design principles and mechanisms that enable it. Additionally it looks to resolve the choice of optimal software for design as well as manufacturing process that will be used for production. Lastly the project seeks to elucidate any issues that reside within the chosen manufacturing process.
ContributorsPotts, Alexander (Author) / Bhate, Dhruv (Thesis director) / Chen, Xiangfan (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor) / Engineering Programs (Contributor)
Created2023-05
Description
Aluminum alloys are commonly used for engineering applications due to their high strength to weight ratio, low weight, and low cost. Pitting corrosion, accelerated by saltwater environments, leads to fatigue cracks and stress corrosion cracking during service. Two-dimensional (2D) characterization methods are typically used to identify and characterize corrosion; however, these methods are destructive and do not enable an efficient means of quantifying mechanisms of pit initiation and growth. In this study, lab-scale x-ray microtomography was used to non-destructively observe, quantify, and understand pit growth in three dimensions over a 20-day corrosion period in the AA7075-T651 alloy. The XRT process, capable of imaging sample volumes with a resolution near one micrometer, was found to be an ideal tool for large-volume pit examination. Pit depths were quantified over time using renderings of sample volumes, leading to an understanding of how inclusion particles, oxide breakdown, and corrosion mechanisms impact the growth and morphology of pits. This process, when carried out on samples produced with two different rolling directions and rolling extents, yielded novel insights into the long-term macroscopic corrosion behaviors impacted by alloy production and design. Key among these were the determinations that the alloy’s rolling direction produces a significant difference in the average growth rate of pits and that the corrosion product layer loses its passivating effect as a result of cyclic immersion. In addition, a new mechanism of pitting corrosion is proposed which is focused on the pseudo-random spatial distribution of iron-rich inclusion particles in the alloy matrix, which produces a random distribution of pit depths based on the occurrence of co-operative corrosion near inclusion clusters.
ContributorsSinclair, Daniel Ritchie (Author) / Chawla, Nikhilesh (Thesis director) / Jiao, Yang (Committee member) / Bale, Hrishikesh (Committee member) / School of International Letters and Cultures (Contributor) / Materials Science and Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
The purpose of this project is to analyze the current state of cancer nanomedicine and its challenges. Cancer is the second most deadly illness in the United States after heart disease. Nanomedicine, the use of materials between 1 and 100 nm to for the purpose of addressing healthcare-related problems, is particularly suited for treating it since nanoparticles have properties such as high surface area-to-volume ratios and favorable drug release profiles that make them more suitable for tasks such as consistent drug delivery to tumor tissue. The questions posed are: What are the current nanomedical treatments for cancer? What are the technical, social, and legal challenges related to nanomedical treatments and how can they be overcome? To answer the questions mentioned above, information from several scientific papers on nanomedical treatments for cancer as well as from social science journals was synthesized. Based on the findings, nanomedicine has a wide range of applications for cancer drug delivery, detection, and immunotherapy. The main technical challenge related to nanomedical treatments is navigating through biological barriers such as the mononuclear phagocyte system, the kidney, the blood-brain barrier, and the tumor microenvironment. Current approaches to meeting this challenge include altering the size, shape, and charge of nanoparticles for easier passage. The main social and legal challenge related to nanomedical treatments is the difficulty of regulating them due to factors such as the near impossibility of detecting nanowaste. Current approaches to meeting this challenge include the use of techniques such as scanning tunneling microscopy and atomic force microscopy to help distinguish nanowaste from the surroundings. More research will have to be done in these and other areas to enhance a major cancer-fighting tool.
ContributorsAbraham, Alfred Francy (Author) / Brian, Jennifer (Thesis director) / Liu, Yan (Committee member) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
This thesis details the process of developing a force feedback system for a small robotic manipulator in order to prevent damage to manipulators and the objects they are grasping, which is a desired feature in many autonomous robots. This includes the research, design, fabrication, and testing of a custom force-sensing resistor and a custom set of jaws to implement the feedback system on. In order to complete this project, extensive research went to designing and building test beds for the commercial and custom force sensors to determine if force values could even be obtained. Then the sensors were implemented on a manipulator and were evaluated for ease of use during assembly and testing, accuracy, and repeatability of results using a test bed designed during the course of this research. Afterwards the custom jaws were designed and fabricated based on problems encountered during testing with the initial set of jaws. The new jaws were then tested on the test bed with the sensors and the force feedback system was implemented on it. The overall system was then evaluated for any current limitations and improvements that could be made in the future to further develop this research and assist with its implementation on other robots. The results of this experiment show that a low-cost force sensor that is easy to mass produce can be implemented on an autonomous robot to add force feedback capabilities to it. It is hopeful that the results from the experiments conducted are implemented on robotic manipulators so the area of force sensing technologies research can be expanded upon and improved.
ContributorsMartin, Anna Lynn (Author) / Berman, Spring (Thesis director) / Rajagopalan, Jagannathan (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
The solid municipal waste contains approximately 60% of organic matter and after varying temperature, pressure and residence time as factors, the temperature influenced the yield at least twice more than the residence time. The pressure had the least effect on the production of the syngas. Different types of hydrogen separation were explored ranging from pressure swing adsorption (PSA) to water splitting, factional/cryogenic method and then hydrogen selective membranes. The membranes were found to be more cost efficient, and easily accessible and fabricated and produced purer hydrogen gas. The different membranes were explored, and their different characteristics were explored, and a decision matrix showed that the polymeric membrane was 1.37 time better than microporous membrane and 1.54 times better than dense metal membrane.
ContributorsAgbo, Benjamin Udama (Co-author) / Buyinza, Allan (Co-author) / Deng, Shuaguang (Thesis director) / Taylor, David (Committee member) / Materials Science and Engineering Program (Contributor) / Chemical Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
In order to produce efficient reverse osmosis membranes, it is necessary to minimize the effects of outside factors on the membrane surface that can reduce the flux of water through the membrane. One such problem is fouling. Fouling happens when particles are deposited on the membrane surface, blocking water flow through the membrane. Over time, the collection of foulants will prevent water through the membrane, increasing the amount of energy required in the system. Microgel, a heat-responsive colloidal gel, shows promise as an anti-foulant coating as it possesses functional groups similar to the membrane and compatible with common foulants and changes volume due to temperature differences. By coating the membrane with the microgel, foulants will attach to the functional groups of the microgel instead of those of the membrane Our hypothesis is that the change in volume of the microgel with different temperatures will help reduce and remove foulants. By functionalizing the surface of the membrane and the microgel, the microgel can covalently bond to the membrane surface and avoid detachment under reverse osmosis conditions. Microgel-coated reverse osmosis membranes have been fluorescently fouled to measure the decrease in foulants with heated crossflow under fluorescent microscopy. This process has shown a 50% decrease in fluorescence on the surface of the membrane indicating a decrease in foulants due to the presence of microgel. Under cross-flow conditions with a low flow rate, the microgel remains on the functionalized membrane for 8 hours with similar anti-fouling performance as the dip-coating process.
ContributorsKraetz, Andrea Nicole (Author) / Thomas, Marylaura (Thesis director) / Perreault, Francois (Committee member) / Chemical Engineering Program (Contributor) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05