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Original Equipment Manufacturer (OEM) is a term used in many industries to describe a company that produces parts and equipment that may be marketed by another manufacturer. In the aviation industry, the aircraft engine OEM refers to the company that manufactures engines powering the aircraft. The OEM manufactures the engine, defines the required maintenance to operate the engines, and recommends product modifications. Product modifications are recommended to improve product safety, durability, reliability, and cost of ownership and are formally communicated through issuance of service bulletins. Properly performing the required maintenance and adopting service bulletins is an important element of maintaining a high standard regarding safety performance. The aircraft engine OEM is the source of knowledge regarding how to properly and effectively perform standard maintenance tasks. The OEM also has information related to service bulletins that is critical to properly assess and adopt service bulletins. This study identifies the critical elements of engagement between aircraft engine OEMs and airlines during two processes. The first process studied was the adoption of service bulletins and included how the airline becomes aware of a service bulletin, how they assess the need to perform the service bulletin, and finally how the airline prepares and executes on the adoption of the service bulletin. The OEM engagement was identified and analyzed during each phase of this process. The second process studied was how the airline identifies when they need support from the OEM to properly complete required maintenance and inspection tasks. OEM engagement was identified and analyzed during this process. Critical elements required for effective and efficient engagement identified in this study are then compared to existing literature on effective interorganizational engagement. Applying the learnings from this study to the more generic process maps developed in previous studies allowed for a specific process map for ensuring effective and efficient engagement between aircraft engine OEMs and airlines, in this specific context. This dissertation is available in open access at AURA: Antioch University Repository and Archive, http://aura.antioch.edu/, and OhioLINK ETD Center, https://etd.ohiolink.edu/.

ABSTRACT In the past Accelerated Vehicle Retirement (AVR) programs have been implemented to combat the economic and environmental costs of automobile dependent societies. Seventy-five such programs have been implemented worldwide since 1990. This thesis examines correlations among factors affecting program performance, the relationship of articulated program objectives to program performance, and how factors affecting program performance influence environmental concerns. Employing a mixed methodology, this analysis answers how an accelerated vehicle retirement program can be designed to maximize desired outcomes and minimize undesirable outcomes. The results of this analysis demonstrate that the order and type of objective stipulated by a program will influence a program's performance, and that relationships among factors affecting program performance can dictate how well a program will function. The framework created from the literature review and from program analysis can apprise planners on how to most effectively design future AVR programs.

At very high altitudes the Reynolds number flow through the low pressure turbine section of the gas turbine engine can drop below 25,000. At these low Reynolds numbers the flow is laminar and extremely susceptible to separation which can lead to increased losses and reduced lift. Small jets of air injected through the suction surface of the airfoil, called Vortex Generator Jets (VGJs), have been shown successful in suppressing separation and maintaining attached flow. Pulsing of these jets has been shown to be as effective as steady jets while reducing the amount of mass flow needed. An experiment using Particle Image Velocimetry (PIV) was set up to study the interaction of the VGJ flow with the main flow. A cascade of Pratt and Whitney Pack-B turbine blades were mounted in the test section of a low speed wind tunnel at Wright Patterson Air Force Base. On the middle six blades were rows of 1mm VGJ holes. The VGJ holes were oriented with a 30o pitch angle and 90o skew angle. The pitch angle is the angle the jet makes with the surface of the turbine blade while the skew angle is the angle the jet makes with the cross-flow. Blowing ratios, a ratio of the jet velocity to the cross-flow velocity, of 0.5, 1, and 2 were examined. These three blowing ratios were selected because they represent when the cross-flow momentum dominates the fluid interaction (B=0.5); when the momentums of the jet flow and cross-flow are equal (B=1); and when the momentum of the jet flow dominates the interaction. Blowing ratios of 0.5 and 1 were studied for pulsing frequencies of 10Hz and 0.4Hz while the blow ratio of 2 was studied only with 10Hz pulsing. A duty cycle of 50% was used for both pulsing frequencies. The two pulsing frequencies allowed data to be taken to show how the pulsed VGJ maintains attached flow (10Hz) and how the pulsed VGJ suppresses the separation bubble (0.4Hz). Results show that jets interacting with separated flow are able to suppress the separation bubble almost immediately for a blowing ratio of 1 and 0.5. The results for suppression and separation growth show the response of the crossflow is very similar in magnitude and timing between the two blowing ratios. The results for the 10Hz pulsing frequency show blowing ratios of 0.5, 1, and 2 are effective. A blowing ratio of 2 is undesirable because it carries more momentum than is needed and would therefore use more massflow than the B=1 or 0.5 case. Results from the B=0.5 case suggest that a blowing ratio of 0.5 is near the minimum effective blowing ratio.