The two-microphone impedance tube test method is a well-established and widely used technique for determining the acoustic absorption coefficient and impedance ratio of materials. This method uses two closely spaced microphones to simultaneously measure the incident and reflected sound waves. A two-microphone impedance tube measurement system made of 6061-T6 Aluminum with a diameter of 3 inches, a 0.5 inch wall thickness, and microphones spaced 2.7 inches apart has been constructed for undergraduate research at Texas Christian University (TCU). These geometrical values suggest a usable frequency range of 50 Hz to 2637.77 Hz as referenced in ASTM Standard E1050-19. Validation of the system was achieved by taking measurements on Owen Corning Type 705 pressed fiberglass board with a 1-inch thickness and comparing them to absorption data provided by the manufacturer. Additional validation measurements were taken without a test sample in place. All validation tests suggest that the TCU impedance tube is an accurate measurement system.

Bacteria, the primary agents of infection in humans, are present on nearly all surfaces. To mitigate the spread of bacteria and infections, disinfectants are commonly used. This study explored the effectiveness of common disinfectants and different methods of disinfection, primarily focusing on the use of spray pumps and a transducer as a mechanism to disinfect surfaces using 70% IPA (Isopropyl Alcohol) or ethanol (often referred to by the brand name Lysol). Tests were conducted on bacterial lawns before incubation. The effectiveness of the tests was determined by observing bacterial growth over the next 24 hours after disinfection. Testing proved that both ethanol and 70% IPA are effective in stopping bacterial growth. While both the transducer and spray pump methods showed success, the transducer/ethanol combination was particularly efficient, using the least amount of disinfectant.

Thermal oxidation is an important process to create a thin film of silicon dioxide on silicon substrates in microfabrication. In this project, thermal oxidation characteristics on the silicon wafer will be analyzed through experiments in the clean room. The research method was conducted in the thermal oxidation furnace in the TCU Cleanroom on nine wafers with different placement orientations in the furnace and three different oxidation temperatures: 950°C, 1000°C, and 1050°C. In addition, oxide thickness measurements between different locations on the wafer were taken to investigate the film uniformity. The data analysis showed three trends: 1. oxide thickness varies across the wafers, 2. oxide thickness varies as a function of the furnace location, and 3. oxide growth rate varies as a function of furnace temperature. This project investigates how these factors impact thermal oxidation, one of the most critical steps in microfabrication

The Digital Micro-Mirror Device (DMD), which was originally developed for digital projection using visible light source, has seen numerous applications in automotive, manufacturing, spectroscopy, and underwater imaging that require wavelength beyond visible. The DMD window is an important part of the packaging that protects the digital mirror array. Since the light goes through the top and bottom surfaces of the window glass twice during operation, the transmittance of the window is usually optimized for the range of wavelengths specified by the applications through optical coatings. In this research work, we will explore the effectiveness of the optical coatings for different types of glasses for window transmittance improvement in visible and near-infrared wavelengths. We will evaluate the transmittance of the existing DMD window glasses and explore ideas of improving transmittance in the NIR range without compromising the effectiveness in the visible light range. In doing so, we would be the light efficiency of the DMD in a wider wavelength range.

Total knee arthroplasty (TKA) is commonly performed to treat severe knee osteoarthritis. Sclerotic subchondral bone may reduce tibial cement fixation by limiting cement interdigitation. Although drilling pilot holes is a common practice to improve fixation, its mechanical effects are not well quantified. In this study, finite element analysis (FEA) with static load fracture mechanics was used to evaluate the effect of drilling on fixation. Factor of safety (FOS) contours were used to define failure, and a failure metric—percent of cement-to-bone contact area failed (PCBCAF)—was introduced as the percentage of the interface with FOS < 1. The experimentally determined failure load of the no-hole model was simulated to obtain a baseline PCBCAF. This baseline was then used to predict the failure load of various drilled configurations (2 mm diameter holes) by identifying the load at which matching PCBCAF occurs.
These results establish PCBCAF as a consistent metric for comparing fixation strength across drilling configurations and guiding experimental design.