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Articles 1 - 14 of 14
Full-Text Articles in Engineering
An Analysis On Recommended United States Air Force Additive Manufacturing Construction Unit Type Code Package For Expeditionary Deployment, Caleb G. Dann
Theses and Dissertations
Additive Manufacturing Construction (AMC) is an emerging technology in the construction industry which utilizes 3-D printing to reduce costs, labor requirements and deviations in quality. This technology has the ability to rapidly produce repeatable construction projects while tailoring each to specific requirements through the use of 3-D designs. One of the primary objectives of the 2018 National Defense Strategy (NDS) is to continue meeting mission demands with a greater focus on the efficient use of resources. AMC has the ability to satisfy the requirements of this objective. The United States Air Force has begun initial print trials but have not …
Defense Industrial Base Mergers And Acquisitions In The Post-Cold War Era, Corey D. Mack
Defense Industrial Base Mergers And Acquisitions In The Post-Cold War Era, Corey D. Mack
Theses and Dissertations
The United States Department of Defense (DoD) relies on prime contractors for weapon system development, acquisition, and sustainability, but the increased consolidation of the Defense Industrial Base (DIB) through mergers and acquisitions (M&A) has raised concerns over reduced competition. This research consists of two studies. The first reviews existing literature to identify factors behind the DIB's increased M&A activity since the 1990s, such as DoD budget cuts and market structure. The second study examines the relationship between a prime contractor's financial health and M&A spending, finding a significant relationship between efficiency and M&A spending. Policymakers can use this information to …
Illuminating The Unknown: A Mixed Methods Exploration Of The Dod Software Factory Ecosystem, Zachary O. Ryan
Illuminating The Unknown: A Mixed Methods Exploration Of The Dod Software Factory Ecosystem, Zachary O. Ryan
Theses and Dissertations
The Department of Defense’s (DoD) software factories are a collection of modern software acquisition programs that commonly employ the agile, network-based business strategies often found within commercial industries. Having been formally recognized by senior leaders for their revolutionary software development approaches, the software factories highlight a cultural shift within the DoD away from traditional organizational practices. As a result of the factories demonstrated successes, the number of programs employing non-traditional strategies is expanding. While this is notable, it also presents a challenge because a comprehensive understanding of the characteristics, structures, and behaviors of the DoD’s software factories does not currently …
Artificial Neural Networks And Gradient Boosted Machines Used For Regression To Evaluate Gasification Processes: A Review, Owen Sedej, Eric Mbonimpa, Trevor Sleight, Jeremy M. Slagley
Artificial Neural Networks And Gradient Boosted Machines Used For Regression To Evaluate Gasification Processes: A Review, Owen Sedej, Eric Mbonimpa, Trevor Sleight, Jeremy M. Slagley
Faculty Publications
Waste-to-Energy technologies have the potential to dramatically improve both the natural and human environment. One type of waste-to-energy technology that has been successful is gasification. There are numerous types of gasification processes and in order to drive understanding and the optimization of these systems, traditional approaches like computational fluid dynamics software have been utilized to model these systems. The modern advent of machine learning models has allowed for accurate and computationally efficient predictions for gasification systems that are informed by numerous experimental and numerical solutions. Two types of machine learning models that have been widely used to solve for quantitative …
Predicting Tf33-Pw-100a Engine Failures Due To Oil Issues Using Survival Analyses, Anna M. Davis
Predicting Tf33-Pw-100a Engine Failures Due To Oil Issues Using Survival Analyses, Anna M. Davis
Theses and Dissertations
In 2007, the Office of the Assistant Secretary of Defense for Sustainment pushed for the need to transition to a Condition Based Maintenance Plus (CBM ) initiative for weapon systems in the U.S. Department of Defense. The CBM initiative can help increase aircraft availability (AA) for the United States Air Force. There are many reasons where AA can be affected but one such issue is engine availability primarily due to oil issues. Within the CBM perspective, this study examines the risk of a jet engine failure due to an oil issue and attempts to predict an engines time until next …
Agile Software Development: Creating A Cost Of Delay Framework For Air Force Software Factories, J. Goljan, Jonathan D. Ritschel, Scott Drylie, Edward D. White
Agile Software Development: Creating A Cost Of Delay Framework For Air Force Software Factories, J. Goljan, Jonathan D. Ritschel, Scott Drylie, Edward D. White
Faculty Publications
The Air Force software development environment is experiencing a paradigm shift. The 2019 Defense Innovation Board concluded that speed and cycle time must become the most important software metrics if the US military is to maintain its advantage over adversaries.1 This article proposes utilizing a cost-of-delay (CoD) framework to prioritize projects toward optimizing readiness. Cost-of-delay is defined as the economic impact resulting from a delaying product delivery or, said another way, opportunity cost. In principle, CoD assesses the negative impacts resulting from changes to the priority of a project.
Fracture Toughness And Fatigue Crack Growth Rate Characterization Of Inconel 718 Formed By Laser Powder Bed Fusion, Charles C. Hohnbaum
Fracture Toughness And Fatigue Crack Growth Rate Characterization Of Inconel 718 Formed By Laser Powder Bed Fusion, Charles C. Hohnbaum
Theses and Dissertations
Continuing improvement in the field of AM of metals provides the opportunity for direct fabrication of aerospace parts. AM was once used in large part for rapid prototyping but improvements in technology and increases in the knowledge base of AM materials has provided the opportunity for manufacture of AM parts for operational use. The ability to create low numbers of unique parts without having to invest in expensive tooling provides great economic incentive to utilize this technique. IN718 is the most common high temperature alloy used in the aerospace industry and lends itself readily to formation by LPBF. The superior …
Learning Curves: An Alternative Analysis, Sharif F. Harris
Learning Curves: An Alternative Analysis, Sharif F. Harris
Theses and Dissertations
Learning curves are used to describe and estimate the cost performance of a serial production process. There are numerous different models and methods, however, it is not definitively known which is preferred. The research objective is to performance compare the more common learning curve models. The research goal is improved understanding of the systemic cost drivers of a production process, their relationship to cost, and present modeling methods. The research method is qualitative analysis combined with statistical regression modeling. The research identified that preference for one function or another depended upon the shape of the data and how well a …
Additive Manufacturing Process Parameter Effects On The Mechanical Properties Of Fused Filament Fabrication Nylon, Eric S. Holm
Additive Manufacturing Process Parameter Effects On The Mechanical Properties Of Fused Filament Fabrication Nylon, Eric S. Holm
Theses and Dissertations
The purpose of this research was to determine how varying Fused Filament Fabrication (FFF) process parameters affect the mechanical properties of PA6 nylon dog-bone specimens produced on the Mark One 3D Printer. A design of experiment (DOE) was conducted using the factors of layer height and raster angle orientation. The mechanical properties measured in the experiment were tensile modulus, yield stress, percent strain at yield, ultimate tensile strength and percent strain at break. An analysis of variance (ANOVA) was performed to identify which factors were statistically significant in influencing mechanical properties. Results of the ANOVA showed that layer height was …
Modeling Reliability Growth In Accelerated Stress Testing, Jason K. Freels
Modeling Reliability Growth In Accelerated Stress Testing, Jason K. Freels
Theses and Dissertations
Qualitative accelerated test methods improve system reliability by identifying and removing initial design flaws. However, schedule and cost constraints often preclude sufficient testing to generate a meaningful reliability estimate from the data obtained in these tests. In this dissertation a modified accelerated life test is proposed to assess the likelihood of attaining a reliability requirement based on tests of early system prototypes. Assuming each prototype contains an unknown number of independent competing failure modes whose respective times to occurrence are governed by a distinct Weibull law, the observed failure data from this qualitative test are shown to follow a poly-Weibull …
Rapid Prototype Development Of A Remotely-Piloted Aircraft Powered By A Hybrid-Electric Propulsion System, Michael P. Molesworth, Jacob K. English
Rapid Prototype Development Of A Remotely-Piloted Aircraft Powered By A Hybrid-Electric Propulsion System, Michael P. Molesworth, Jacob K. English
Theses and Dissertations
Remotely-Piloted Aircraft (RPA) provide users with unique mission capabilities, particularly on-demand overhead surveillance. However, a capability gap has been identified between the range and endurance of RPAs powered by internal combustion engines (ICE) and the reduced acoustic signature and smaller logistical footprint associated with electric-powered RPAs. This research, sponsored by the Office of the Secretary of Defense, aims at advancing systems engineering education by evaluating the utility of a tailored systems engineering approach. The tailored systems engineering approach used herein focuses on conducting a concept evaluation study on the rapid prototype development of a parallel hybrid-electric RPA (HE-RPA) and its …
An Analysis Of The Relationship Between Environmental Management And Environmental Compliance At Marine Corps Installations, Bevin J. Keen
An Analysis Of The Relationship Between Environmental Management And Environmental Compliance At Marine Corps Installations, Bevin J. Keen
Theses and Dissertations
Environmental compliance on military is challenging for a number of reasons, including the complexity of regulations, and the variety of operations which impact the environment. At times, public concerns and penalties stemming from environmental issues has infringed upon the United States Marine Corps' (USMC) ability to use all installation resources without restriction. This thesis examines which facets of environmental management are closely associated with high levels of compliance. Five variables of interest: Total Compliance, Total Management, Audit Management, Policy Management, and Training Management were isolated from 1998-2004 USMC environmental audit data, and subjected to statistical analysis. Through the examination of …
A Comparison Of Consistent Versus Inconsistent Scheduling Rules In A Flow Shop Environment, Nicola Gismondi
A Comparison Of Consistent Versus Inconsistent Scheduling Rules In A Flow Shop Environment, Nicola Gismondi
Theses and Dissertations
A consistent scheduling rule is one which will ensure a job's priority (relative to all other job's) will remain constant as it moves from queue to queue in a production system. Previous research concerning flow shop priority scheduling rules focused on comparison of either consistent or inconsistent rules. Conversely, this study sought to provide additional insight by comprising consistent and inconsistent rules in a flow shop environment The Air Force uses both types of rules in maintenance and logistics scheduling. Time and money can be saved if the scheduling managers can better understand the effect of consistency on a system. …
Just In Time Manufacturing: A Migration From Materials Requirements Planning, Scott A. Koehler
Just In Time Manufacturing: A Migration From Materials Requirements Planning, Scott A. Koehler
Theses and Dissertations
Manufacturing planning and control systems play an important role in an organization's effectiveness. Over the past twenty to thirty years, U.S. manufacturing companies have faced increasing competition for market share from Japanese and other Pacific rim countries. This thesis will investigate the evolutionary path followed by manufacturing companies that have implemented various manufacturing planning and control systems. Specifically, Materials Requirements Planning (MRP) and Just In Time (JIT) production will be analyzed. MRP is a means of convening demand for the final product into a requirements schedule for the various components comprising that product. The JIT philosophy calls for continuously improving …