REU Projects for Summer 2008
The following are summaries of the research projects conducted during the 2008 Metrology REU, adapted from submissions by REU participants.
Fabrication and Characterization of Hydrogels Encapsulated with Osteoblasts
Hydrogels are constructed using ultraviolet light to catalyze the polymerization of poly(ethylene glycol) (PEG), thereby encapsulating cells in a flexible matrix approximately one inch in diameter. In order for these scaffolds to be employed as tissue replacements, they must be analyzed for cell viability, maturity, and density. We have employed two different means to characterize the tissues that result from ultraviolet polymerization of the scaffold. First, we used histological methods to fix, section, and visualize the scaffolds. Importantly, we found that immersion in organic solvent played a critical role in the ability to impregnate the scaffold with paraffin. Second, we used a confocal microscope to take images of our scaffold layer by layer, and create a model to help us analyze the structural properties of the scaffold. Here, we found cell density to be crucial to the acquisition of informative images.
Experimental Study of Material Removal Rate in Flat Lapping
Lapping is a machining operation that can exhibit two or three body wear on a workpiece to produce a surface that is extremely flat, smoother, and usually free of surface imperfections. The lapping operation is often dependent on the skill of the operator to provide a quality lapped component. The experiment presented will be an observation of material removal rate and roughness over extended periods with respect to variable velocity and will be modeled after a journal article submitted by Le and Peterson in 1999. The experiment presented here will make correlations supporting abrasive particle size determines the limit to how smooth a surface can be. Also lapping using three-body wear follow the Preston equation, but the time dependent particle breakdown as described by Le and Peterson does not appear to be present. However, high lapping speeds appears to cause negative difference of material removal rate from Preston’s relation.
Shear Modulus of Porous Titanium Constructs Fabricated with Electron Beam Melting
Electron Beam Melting is a state of the art process by which a metal powder is laid and melted one layer at a time to create a 3D object from the ground up. This exciting new process is quite possibly the way of manufacturing in the future, but as for now there is very little known about the way in which metals created by electron beam melting behave. Additionally there is little known about what happens when a metal is made to not be fully solid. This research aims to discover the shear strength of one of these parts, specifically a 55% porous titanium cube. The problem begins with finding a good way to put a cube under shear stress, which was done by embedding it in a fixture made from stress proof steel, epoxying it in place, and then placing a brass ring around the entirety of the fixture to ensure there is no slippage. This fixture was then placed in a tensile-force generating machine and pulled apart, with the focal point of the force being applied in shear to the sample.
Two- and Three-Body Wear During Flat Lapping of SS304 and Al6061
The two-body and three-body wear mechanisms in the lapping of Al6061 and SS304 were studied in this project. Through the lapping process, the goal was to find the optimum load that could be placed on these samples for the purpose of maximizing finishing, while preventing metal burn. It is known that two-body wear contributes to the wear on these samples. Thus the way to determine the optimum load was to determine the load at which two-body wear becomes predominant.
Business Case Analysis
The students were divided into two teams. One team was asked to create an educational website, designed to be a resource for anyone with little or no prior understanding of fixture design. The web site could be browsed for a specific topic, or can be read through to gain a more comprehensive understanding of fixture design and application.
The following main sections—Basic Theory, Locators, Clamps, Types of Jigs and Fixtures, and Applications provide a good structure for understanding fixtures. These pages were intended to work as a wiki in that they can be commented on or modified to improve the scope of the concepts covered. As an aid in specific fixture design and use, the following external links could be used. The second group worked on a facility proposal for a Reverse Engineering and Rapid Manufacturing unit.
The following are summaries of the research projects conducted during the 2008 Metrology REU, adapted from submissions by REU participants.
Fabrication and Characterization of Hydrogels Encapsulated with Osteoblasts
Hydrogels are constructed using ultraviolet light to catalyze the polymerization of poly(ethylene glycol) (PEG), thereby encapsulating cells in a flexible matrix approximately one inch in diameter. In order for these scaffolds to be employed as tissue replacements, they must be analyzed for cell viability, maturity, and density. We have employed two different means to characterize the tissues that result from ultraviolet polymerization of the scaffold. First, we used histological methods to fix, section, and visualize the scaffolds. Importantly, we found that immersion in organic solvent played a critical role in the ability to impregnate the scaffold with paraffin. Second, we used a confocal microscope to take images of our scaffold layer by layer, and create a model to help us analyze the structural properties of the scaffold. Here, we found cell density to be crucial to the acquisition of informative images.
Experimental Study of Material Removal Rate in Flat Lapping
Lapping is a machining operation that can exhibit two or three body wear on a workpiece to produce a surface that is extremely flat, smoother, and usually free of surface imperfections. The lapping operation is often dependent on the skill of the operator to provide a quality lapped component. The experiment presented will be an observation of material removal rate and roughness over extended periods with respect to variable velocity and will be modeled after a journal article submitted by Le and Peterson in 1999. The experiment presented here will make correlations supporting abrasive particle size determines the limit to how smooth a surface can be. Also lapping using three-body wear follow the Preston equation, but the time dependent particle breakdown as described by Le and Peterson does not appear to be present. However, high lapping speeds appears to cause negative difference of material removal rate from Preston’s relation.
Shear Modulus of Porous Titanium Constructs Fabricated with Electron Beam Melting
Electron Beam Melting is a state of the art process by which a metal powder is laid and melted one layer at a time to create a 3D object from the ground up. This exciting new process is quite possibly the way of manufacturing in the future, but as for now there is very little known about the way in which metals created by electron beam melting behave. Additionally there is little known about what happens when a metal is made to not be fully solid. This research aims to discover the shear strength of one of these parts, specifically a 55% porous titanium cube. The problem begins with finding a good way to put a cube under shear stress, which was done by embedding it in a fixture made from stress proof steel, epoxying it in place, and then placing a brass ring around the entirety of the fixture to ensure there is no slippage. This fixture was then placed in a tensile-force generating machine and pulled apart, with the focal point of the force being applied in shear to the sample.
Two- and Three-Body Wear During Flat Lapping of SS304 and Al6061
The two-body and three-body wear mechanisms in the lapping of Al6061 and SS304 were studied in this project. Through the lapping process, the goal was to find the optimum load that could be placed on these samples for the purpose of maximizing finishing, while preventing metal burn. It is known that two-body wear contributes to the wear on these samples. Thus the way to determine the optimum load was to determine the load at which two-body wear becomes predominant.
Business Case Analysis
The students were divided into two teams. One team was asked to create an educational website, designed to be a resource for anyone with little or no prior understanding of fixture design. The web site could be browsed for a specific topic, or can be read through to gain a more comprehensive understanding of fixture design and application.
The following main sections—Basic Theory, Locators, Clamps, Types of Jigs and Fixtures, and Applications provide a good structure for understanding fixtures. These pages were intended to work as a wiki in that they can be commented on or modified to improve the scope of the concepts covered. As an aid in specific fixture design and use, the following external links could be used. The second group worked on a facility proposal for a Reverse Engineering and Rapid Manufacturing unit.
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