REU Projects for Summer 2002
The following are summaries of the research projects conducted during the 2002 Metrology REU, adapted from submissions by REU participants.
Roughness Metrology
The objective of this study was to compare the roughness measuring capabilities of a mechanical profilometer and an atomic force microscope. Roughness readings were taken of polished aluminum samples and mean roughness (Ra) and root mean square roughness (Rq) were then determined and statistically analyzed.
Experimental results showed that the profilometer gave quicker and more accurate readings for rougher surfaces, while the AFM gave much more accurate readings for smooth surfaces. For surfaces with moderate roughness (arithmetic means of 100-150nm), both instruments gave similar results.
Coordinate Metrology
The objective of this study was to find a combination of sample size and sampling strategy that will give optimal flatness measurements using a coordinate measuring machine. The sample sizes tested were 9,16, 64, 100, and 256. The sampling strategies tested were uniform, random, and Hammersley.
The conclusions were that the best size regardless of strategy for a 9 square inch area is 64 samples (or 7.1 samples per square inch). The best strategy regardless of size was uniform sampling. When using uniform sampling, there were no statistically significant differences in sample sizes; therefore, the best size and strategy combination was 9 samples (1 sample per square inch) with uniform sampling. Using this combination is the least time consuming (and thus cost efficient) method for obtaining accurate flatness measurements.
Laser Doppler Velocimetry
The students conducted a series of experiments in order to gain a better understanding of Laser Doppler Velocimetry (LDV). One experiment was to measure fringe spacing and then compare the measurements to fringe spacing predicted by the fringe model. The measured fringe spacing was very close to the predicted fringe spacing. After measuring the fringe spacing, the operation of LDV was verified. This was achieved by using LDV to measure the velocity of the outer edge of a rotating disk and comparing it to the velocity predicted by the equation : (f = frequency in rpm and d = diameter of the disk). The differences in the velocities were inconsistent by about 5-6%. The probable cause for the majority of the difference was misalignment of the edge of the disk with the laser beams.
Finally, measurements of an air jet were made using LDV. First, the center of the air jet was located. This center was consistently 15% below the expected velocities predicted by the equation. Once the center was confirmed, development of the helium jet was observed as it exited the stainless steel tube. Observation showed that the helium curved inward slightly toward its own center immediately upon exit and then bows outward well past the edge of the tube as the flow continues vertically.
Raman Spectroscopy
The objective of this research was to work with the CoMoCat process of producing nanotubes by measuring the diameter distribution of single wall carbon nanotubes. Measuring and characterizing the sizes of the diameters may result in certain reproducibility amongst nanotube sizes, making the CoMoCat process cerifiable. It was hypothesized that as the production temperature increased, the diameter size also increased.
After collecting Raman spectroscopy and TEM image data from nanotubes prepared at 750°C and 850°C, it was concluded that diameter sizes do in fact increase with temperature with a 95% confidence.
Process Measurements
The objective of this study was to find a better model than the traditionally used Euclidean mathematics to describe the cutting process on a lathe. Specifically, it investigated the validity of using fractals to model friction on the cutting tool. The experiment investigated four speeds, two feed rates, two metal types, and two cutting tools for a total of 32 samples. After completing all 32 runs on the lathe, the cutting tools were analyzed using a scanning electron microscope.
The friction was analyzed by investigating sticking and sliding regions on the tool surface. Observations indicated that as the speeds progressed, the area of buildup on the edge of the cutting tool decreased. Using box-counting, the results showed that the slipping and sticking regions could both be modeled by a fractal.
Wireless Interactions
The objective of this research was to investigate the interaction between implantable medical devices (such as pacemakers) and a wireless wand system used for security monitoring. The study focused on determining the modes of any implantable device interaction and identifying operating conditions that produced the interaction.
All of the implantable devices experienced some type of interaction with the wand system. The implantable device returned to its normal operation as soon as the wand sensor was removed. The overall rate of interaction was 76.25% and the maximum coplanar (X-Y) distance between the device and the wand at which interaction occurred was 10.82 inches.
Business Cases
The students were broken into three teams. These teams were given the task of creating a complete business case analysis for a phased approach to a complete, dedicated, multi-disciplined, self-sufficient laboratory over three to five years. Each team was assigned a different type of laboratory, with the three types being: metrology, reverse engineering, and microscopy. Although the students were given the freedom to organize the business case however they chose, they were required to address current capabilities, requirements for facility, equipment, and personnel, and the cost and benefits.
The following are summaries of the research projects conducted during the 2002 Metrology REU, adapted from submissions by REU participants.
Roughness Metrology
The objective of this study was to compare the roughness measuring capabilities of a mechanical profilometer and an atomic force microscope. Roughness readings were taken of polished aluminum samples and mean roughness (Ra) and root mean square roughness (Rq) were then determined and statistically analyzed.
Experimental results showed that the profilometer gave quicker and more accurate readings for rougher surfaces, while the AFM gave much more accurate readings for smooth surfaces. For surfaces with moderate roughness (arithmetic means of 100-150nm), both instruments gave similar results.
Coordinate Metrology
The objective of this study was to find a combination of sample size and sampling strategy that will give optimal flatness measurements using a coordinate measuring machine. The sample sizes tested were 9,16, 64, 100, and 256. The sampling strategies tested were uniform, random, and Hammersley.
The conclusions were that the best size regardless of strategy for a 9 square inch area is 64 samples (or 7.1 samples per square inch). The best strategy regardless of size was uniform sampling. When using uniform sampling, there were no statistically significant differences in sample sizes; therefore, the best size and strategy combination was 9 samples (1 sample per square inch) with uniform sampling. Using this combination is the least time consuming (and thus cost efficient) method for obtaining accurate flatness measurements.
Laser Doppler Velocimetry
The students conducted a series of experiments in order to gain a better understanding of Laser Doppler Velocimetry (LDV). One experiment was to measure fringe spacing and then compare the measurements to fringe spacing predicted by the fringe model. The measured fringe spacing was very close to the predicted fringe spacing. After measuring the fringe spacing, the operation of LDV was verified. This was achieved by using LDV to measure the velocity of the outer edge of a rotating disk and comparing it to the velocity predicted by the equation : (f = frequency in rpm and d = diameter of the disk). The differences in the velocities were inconsistent by about 5-6%. The probable cause for the majority of the difference was misalignment of the edge of the disk with the laser beams.
Finally, measurements of an air jet were made using LDV. First, the center of the air jet was located. This center was consistently 15% below the expected velocities predicted by the equation. Once the center was confirmed, development of the helium jet was observed as it exited the stainless steel tube. Observation showed that the helium curved inward slightly toward its own center immediately upon exit and then bows outward well past the edge of the tube as the flow continues vertically.
Raman Spectroscopy
The objective of this research was to work with the CoMoCat process of producing nanotubes by measuring the diameter distribution of single wall carbon nanotubes. Measuring and characterizing the sizes of the diameters may result in certain reproducibility amongst nanotube sizes, making the CoMoCat process cerifiable. It was hypothesized that as the production temperature increased, the diameter size also increased.
After collecting Raman spectroscopy and TEM image data from nanotubes prepared at 750°C and 850°C, it was concluded that diameter sizes do in fact increase with temperature with a 95% confidence.
Process Measurements
The objective of this study was to find a better model than the traditionally used Euclidean mathematics to describe the cutting process on a lathe. Specifically, it investigated the validity of using fractals to model friction on the cutting tool. The experiment investigated four speeds, two feed rates, two metal types, and two cutting tools for a total of 32 samples. After completing all 32 runs on the lathe, the cutting tools were analyzed using a scanning electron microscope.
The friction was analyzed by investigating sticking and sliding regions on the tool surface. Observations indicated that as the speeds progressed, the area of buildup on the edge of the cutting tool decreased. Using box-counting, the results showed that the slipping and sticking regions could both be modeled by a fractal.
Wireless Interactions
The objective of this research was to investigate the interaction between implantable medical devices (such as pacemakers) and a wireless wand system used for security monitoring. The study focused on determining the modes of any implantable device interaction and identifying operating conditions that produced the interaction.
All of the implantable devices experienced some type of interaction with the wand system. The implantable device returned to its normal operation as soon as the wand sensor was removed. The overall rate of interaction was 76.25% and the maximum coplanar (X-Y) distance between the device and the wand at which interaction occurred was 10.82 inches.
Business Cases
The students were broken into three teams. These teams were given the task of creating a complete business case analysis for a phased approach to a complete, dedicated, multi-disciplined, self-sufficient laboratory over three to five years. Each team was assigned a different type of laboratory, with the three types being: metrology, reverse engineering, and microscopy. Although the students were given the freedom to organize the business case however they chose, they were required to address current capabilities, requirements for facility, equipment, and personnel, and the cost and benefits.
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