A main limitation of biomedical devices is the inability to start, stop, and control cell growth making it crucial to develop biomaterial surfaces that induce a desired cellular response. Micropatterns of ridges and p...
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A main limitation of biomedical devices is the inability to start, stop, and control cell growth making it crucial to develop biomaterial surfaces that induce a desired cellular response. Micropatterns of ridges and pillars were created in a siloxane elastomer (Dow Corning) by casting against epoxy replicates of a micromachined silicon wafer. Silicone oils were incorporated to determine the change in modulus and surface energy caused by these additives. SEM and white light interference profilometry verified that the micropatterning process produced high fidelity, low defect micropatterns. mechanical analysis is indicated that varying the viscosity, weight percent and functionality of the added silicon oil could change the elastic modulus by over an order of magnitude (0.1-2.3 MPa). As a self-wetting resin, silicone oils migrate to the surface, hence changing the surface properties from the bulk. Both topographical and chemical features define the surface energy, which in combination with elastic modulus, dictate biological activity. The results imply that the morphology, mechanical properties and surface energy of the siloxane elastomer can be modified to elicit a specific cell response as a function of engineered topographical and chemical functionalization.
The microstructures of EB-PVD TBC's have been characterized as a function of angular position and cylinder height on stationary cylindrical surfaces in the coating chamber. The microstructures were evaluated using...
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The microstructures of EB-PVD TBC's have been characterized as a function of angular position and cylinder height on stationary cylindrical surfaces in the coating chamber. The microstructures were evaluated using x-ray diffraction for qualitative crystallographic texture as well as by optical microscopy and scanning electron microscopy for crystal column growth morphology. The results revealed several very strong crystallographic textures as well as a variety of crystal growth morphology.
The coating thickness profiles for EB-PVD TBCs deposited on stationary cylinders have been experimentally measured and theoretically modeled using Knudsen's cosine law of emissions {1}. A comparison of the experim...
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The coating thickness profiles for EB-PVD TBCs deposited on stationary cylinders have been experimentally measured and theoretically modeled using Knudsen's cosine law of emissions {1}. A comparison of the experimental results with the model reveals that the model needs to be modified to account for the sticking coefficient as well as a ricochet factor. These results are also discussed in terms of the effects of substrate temperature on the sticking coefficient, the ricochet factor, and coating density.
The use of several moral theories to analyze the legitimacy of engineering codes of conduct is discussed. Four different types of moral theories include, utilitarian theories, duty theories, rights theories and virtur...
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The use of several moral theories to analyze the legitimacy of engineering codes of conduct is discussed. Four different types of moral theories include, utilitarian theories, duty theories, rights theories and virture theories. engineering codes of conduct are not absolute standards which cannot be questioned. The weaknesses in these codes can be identified by appropriately using these different moral theories and the weaknesses should be modified.
Scanning Kelvin probe microscopy (SKPM) and conductive atomic force microscopy (C- AFM) are used to image surfaces of GaN grown by molecular beam epitaxy (MBE). Numerical simulations are used to assist in the interpre...
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Scanning Kelvin probe microscopy (SKPM) and conductive atomic force microscopy (C- AFM) are used to image surfaces of GaN grown by molecular beam epitaxy (MBE). Numerical simulations are used to assist in the interpretation of SKPM images. Detailed analysis of the same area using both techniques allows imaging of surface potential variations arising from the presence of negatively charged dislocations and dislocation-related current leakage paths. Correlations between the charge state of dislocations, conductivity of leakage current paths, and possibly dislocation type can thereby be established. Approximately 25% of the leakage paths appear to be spatially correlated with negatively charged dislocation features. This is approximately the level of correlation expected due to spatial overlap of randomly distributed, distinct features of the size observed, suggesting that the negatively charged dislocations are distinct from those responsible for localized leakage paths found in GaN. The effects of charged dislocation networks on the local potential profile is modeled and discussed.
The microstructure of epitaxial InAs thin films grown by MOCVD on mask-patterned "LEO" (lateral epitaxial overgrowth) GaAs and on unpatterned GaAs substrates was studied using double-crystal x-ray diffractio...
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The microstructure of epitaxial InAs thin films grown by MOCVD on mask-patterned "LEO" (lateral epitaxial overgrowth) GaAs and on unpatterned GaAs substrates was studied using double-crystal x-ray diffraction, scanning electron microscopy and cross-sectional transmission electron microscopy. This paper describes the improvement in crystal quality (factor of 20 reduction in x-ray rocking curve width), the order of magnitude reduction in dislocation density, and the rearrangement of the remaining extended defects that were observed in the LEO material when compared to the film grown on the unpatterned wafer.
This paper presents the newly designed fiber optic pressure sensor using the TR-EFPI fiber optic sensor with a single mode fiber (SMF) and a micro fabricated diaphragm. The output signal of TR-EFPI fiber optic pressur...
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This paper presents the newly designed fiber optic pressure sensor using the TR-EFPI fiber optic sensor with a single mode fiber (SMF) and a micro fabricated diaphragm. The output signal of TR-EFPI fiber optic pressure sensor can be analyzed based on the spliced based model and large deflection theory. Then, we can design the optimal length between the thin film of diaphragm and the end of single mode fiber. Therefore, we can obtain the relation between the deflection of thin film and applied pressure using the large deflection theory. From these analyses, the relation between the applied pressure and the output signal of TR-EFPI fiber optic sensor can be simulated. Based on theses process, we can design the TR-EFPI fiber optic pressure sensor measuring various conditions by changing the size of thin film. As the newly designed TR-EFPI fiber optic pressure sensor can be fabricated in small size and has good sensitivity, it can be applied to medical instrument like pressure sensor and force sensor for catheter and minimum invasive surgery robot for safe surgery.
This work considers a new technique for damage detection in vibration-based structural health monitoring. The technique involves exciting a structure with a low-dimensional chaotic input, reconstructing the attractor,...
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An innovative product-oriented manufacturing curriculum is discussed. It enhance manufacturing degree programs at the University of Missouri-Rolla (UMR) and St. Louis Community College at Florissant Valley (FV). The p...
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An innovative product-oriented manufacturing curriculum is discussed. It enhance manufacturing degree programs at the University of Missouri-Rolla (UMR) and St. Louis Community College at Florissant Valley (FV). The project will impact UMR's two BS degree option programs in manufacturing and MS degree programs in manufacturing and FV's manufacturing engineering and technology programs. An integrative and collaborative manufacturing program is established to reinforce and sharpen critical competencies of students. The project course will provide students with the experience of integrating the technical knowledge they have learned from various other courses.
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