Transient liquid-phase diffusion brazing is used in precision, hermetic joining applications as a replacement for diffusion bonding to reduce cycle times, reduce bonding pressure and improve yields. Studies showed that the interlayer used in diffusion brazing can be detrimental due to the use of melting point depressants (MPDs). The goal...
Distractions and interruptions are common occurrences in an operating room (OR), but little is known about their effects on surgical task performance. Based on human factors research, it was hypothesized that realistic distractions and interruptions in an OR would adversely impact surgical task performance. Because of the concern of patient...
Since the Industrial Revolution, automated systems have increasingly become a part of everyday life. Automated systems range in scale and scope from simple assists to complete robotic replacements. Inexpensive integrated circuits, sensors and microprocessors have allowed automated systems to become smaller, cheaper and more prevalent. Identifying appropriate opportunities for automation,...
Continuous Improvement (CI) is an integral part of hospital administration. This study examined the relationship between five CI variables against six hospital criterion measures of, wait times to prepare a room, patient costs per day, waiting time for lab results, reportable errors, patient satisfaction, and employee satisfaction. The research was...
Currently, the temporal arc distribution across the ingot during the vacuum arc remelting (VAR) process is not a known or monitored parameter. It is has previously been shown that arcs can spatially constrict during VAR, and this constriction can lead to undesired defects in the material. Additionally, correct accounting for...
Biological organisms, phenomena and strategies, herein referred to as biological systems, provide a rich set of analogies that can be used to inspire engineering innovation. Biologically-inspired, or biomimetic, designs are publicly viewed as creative and novel solutions to human problems. Moreover, some biomimetic designs have become so commonplace that it...
Silicon carbide (SiC) and aluminum nitride (AlN) exhibit a combination of thermal and mechanical properties that are relevant to applications in electronics, aerospace, defense and automotive industries. However, the successful translation of these properties into final applications lies in the net-shaping of these ceramics into fully dense microstructures. Increasing the...
Fractal-like branching microchannel flow networks have been found to improve wall temperature uniformity and decrease both pressure drop and flow power compared to arrays of straight microchannels. The present study seeks to maximize the benefits of fractal-like branching channels by means of a gradient-based optimization algorithm. The algorithm identifies the...
For manufacturing and service industries to stay competitive in this rapidly changing, globalized world, one of the most important operations, and one that many businesses struggle to plan and manage efficiently, is material handling. There has been a large amount of research on various vehicle routing problems (VRPs) in recent...
A number of computational tools now exist to aid in developing conceptual solutions based on a functional description of a design problem. A key limitation of these tools is the way results are organized for presentation to the user. In general, results are an undifferentiated mass of potential solutions. Analysis...
Technologies such as avionics and power electronics are driving the demand for thermal management schemes towards high heat fluxes and low surface temperatures. Typically, these applications require the dissipation of heat fluxes in the rage of 100-1000 W/cm² while maintaining surface temperatures lower than about 85 °C. Phase-change heat transfer...
Critical success factors (CSFs) are those things that must be done correctly for a project to be successful; however, CSFs are not sufficient by themselves to guarantee success. CSFs, as identified in the literature, vary from study to study. In addition, previous studies have not typically included contextual details for...
While the locomotion performance of legged robots over flat terrain or known obstacles has improved over the past few decades, they have yet to equal the performance of their animal counterparts over variable terrain. This work analyzes a multi-legged reduced order model of cockroach locomotion on variable slopes which will...
This research addresses fleet-sizing for reusable containers that are used for
protection, transportation, and storage of parts between a component plant and
assembly plant. These reusable containers are often expensive and occupy a
large amount of storage space when empty and full. Having a large container
fleet comes with higher...
A new adhesive bonding method is introduced for microlamination architectures, for producing low-temperature microchannel arrays in a wide variety of metals. Sheet metal embossing and chemical etching processes have been used to produce sealing bosses and flow features, resulting in approximately 50% fewer laminae over traditional methods. These lamina designs...
Microchannel process technology (MPT) offers several advantages to the field of nanomanufacturing: 1) improved process control over very short time intervals owing to shorter diffusional distances; and 2) reduced reactor size due to high surface area to volume ratios and enhanced heat and mass transfer. The objective of this thesis...
While many organizations claim to "put safety first," safety is rarely considered early in the design process when system-level architectural decisions are made. Instead, system design follows an abstraction-to-detail process to first meet functional and then performance requirements. Following this process, safety assurance occurs in the later stages of design...
A gap exists in the methods used in industry and available in academia that prevents customers and engineers from having a voice when considering engineering risk appetite in the dynamic shaping of early-phase conceptual design trade study outcomes. Current methods used in Collaborative Design Centers either collect risk information after...
Engineers have long been inspired by nature's flyers. Such animals navigate complex environments gracefully and efficiently by using a variety of evolutionary adaptations for high-performance flight. Biologists have discovered a variety of sensory adaptations that provide flow state feedback and allow flying animals to feel their way through flight. A...
Natural fibers are gaining popularity as reinforcement materials for thermoset resins over the last two decades. Natural fibers are inexpensive, abundant, renewable and environmentally friendly. Kenaf fibers are one of the natural fibers that can potentially be used for reinforcing unsaturated polyester (UPE). As a polymer matrix, UPE enjoys a...
This work proposes a framework of concept generation and evaluation that takes into consideration the benefit of creativity and innovation in current market trends. By educating engineers in how to increase creativity in concept design and assess it quantitatively, the next generation of designers will be a step ahead of...
There are many options available when selecting a computational model for
two-phase flows. It is important to understand all the features of the model
selected, including when the model is appropriate and how using it may affect
your results. This work examines how volume displacement effects in two-phase
Eulerian-Lagrangian models...
This research is aimed at obtaining a better understanding of the impact of the use of collaborative and simulation sessions for learning lean principles and methods. Study participants were enrolled in a Lean Manufacturing System Engineering (IE436/536) course at Oregon State University or at three other business and engineering universities...
Characterization of local boiling trends, in addition to the typically reported area-averaged trends, is essential for the robust design and implementation of phase change technologies to sensitive heat transfer applications such as electronics cooling. Obtaining the values of heat fluxes corresponding to locally varying surface temperatures has been a challenge...
Porous media flows are encountered in many natural and man-made systems such as gas adsorption, filtration, heat exchangers, combustion, catalytic reactors and groundwater hydrology. This study experimentally investigates these flows as function of pore Reynolds number, Re[subscript pore]. The pore Reynolds number is based on the porous bed hydraulic diameter,...
There are many different types of automatic data collection technologies that have been used in transportation system applications such as pneumatic tubes, radar, video cameras, inductive loops detectors, wireless toll tags, and global positioning systems (GPS). Nevertheless, there are still multiple examples of important and helpful transportation system data that...
In this dissertation, a group of vehicle dynamics simulation tools is developed with two primary goals: to accurately represent vehicle behavior and to provide insight that improves the understanding of vehicle performance. Three tools are developed that focus on tire modeling, vehicle modeling and lap time simulation.
Tire modeling is...
In this work, flow through synthetic arrangements of contacting spheres is studied
as a model problem for porous media and packed bed type flows. Direct numerical
simulations are performed for moderate pore Reynolds numbers in the range,
10 ≤ Re ≤ 600, where non-linear porescale flow features are known to...
In-situ vapor extraction is performed by applying a pressure differential across a hydrophobic porous membrane that forms a wall of the channel as a means of reducing the local quality of flow boiling within the channel. As the local quality is reduced, the heat transfer capability can be improve while...
This dissertation addresses a hybrid-flow shop scheduling problem with dual resource constraints in a supply chain. Most of the traditional scheduling problems deal with machine as the only resource. However, other resources such as labor is not only required for processing jobs but are often constrained. Considering the second resource...
Recent advances in multiagent learning have led to exciting new capabilities spanning fields as diverse as planetary exploration, air traffic control, military reconnaissance, and airport security. Such algorithms provide a tangible benefit over traditional control algorithms in that they allow fast responses, adapt to dynamic environments, and generally scale well....
An open area of research in complex systems is to move reliability and failure assessments earlier in the engineering design process. When compared to later design, early decisions are cost effective and have a large impact on the system. Standard methods are limited by the availability of data and often...
In this work, continuous synthesis routes for binary nanoparticles using advantages of microchannel mixing (low diffusion distances and higher mass transfer) and fast heating rates provided by ultrasound induced heating are investigated. In addition, the application of silica nanoparticles in anti-reflective coatings on glass and understanding the structure property-performance correlation...
Stock loss and out-of-stocks are outcomes of poorly designed inventory management systems and can lead to significant revenue losses. Inventory management systems (IMS) based on radio frequency identification (RFID) have the potential to minimize these losses if they are properly designed and deployed. However, the placement of RFID readers to...
A novel microscale combustor-heat exchanger (μCHX) for hydrogen storage applications is presented in this dissertation. The design of the μCHX is motivated by its application to two particular systems for automotive use- those that utilize metal hydrides (MH) and cryo-adsorbents (CA) to store hydrogen. Thermal energy needs to be supplied...
In this research, a bi-criteria group scheduling problem is investigated in hybrid flow shop (HFS) environments, where the parallel machines in each stage are unrelated, meaning not identical. The objective of the problem is to minimize a linear combination of the total weighted completion times as a means of complying...
This research is an effort to explore the nature of good work, a concept that describes work that is beneficial to the physical, psychological, and social dimensions of its stakeholders, including and especially the worker. This effort is divided into four distinct parts. First, the construct of good work is...
Multiagent learning with cooperative coevolutionary algorithms is a critical area of research, and is relevant to many real-world applications including air traffic control, distributed sensor network control, and game-theoretic applications such as border patrol. A key difficulty in multiagent learning is the credit assignment problem, where the impact of each...
Advances of colloidal nanomaterials for societal benefit have been hampered by the high cost and low quality of nanoparticles (NPs). The production of high quality nanoparticles within colloidal suspension has two related concerns; (1) current high production rates methods of synthesizing nanoparticles result in a larger range of particle size,...
Tensegrity structures are composed of pure compressional elements that are connected via a network of pure tensional elements. The concept of tensegrity promises numerous advantages to the field of robotics. Tensegrity robots are, however, notoriously difficult to control due to their oscillatory nature and nonlinear interaction between the components. Multiagent...
This research considers a combinatorial optimization scheduling problem in the assembly of printed circuit boards (PCBs) in electronic manufacturing. For the first time in this research, the preparation process, which is typically called kitting operation, is paid attention to and is performed along with the assembly operation, described in this...
In this dissertation, a two stage flexible flow shop scheduling problem is studied, where in stage 1, there are identical batch processors (burnout ovens) and in stage 2, there are identical discrete processors (furnaces). Batch processors perform a pre-heating process on a batch of jobs at a time and discrete...
A microchannel-based hemodialyzer offers a novel approach to hemodialysis practice and holds many promises for improving dialysis treatment efficiency and quality of life for kidney patients. The hollow fiber hemodialyzer, a conventional dialysis device, has certain limitations including non-uniformity of the dialysate flow path which necessitates the use of a...
Infrastructure systems are a critical component supporting today's modern society. From
power grids to traffic networks, we rely on these systems to perform as intended, despite
the various sources of uncertainty present in their operation. Designing for system
robustness can help mitigate the impact of failures caused by unexpected events....
As modern systems continue to increase in size and complexity, they pose significant safety and risk management challenges. System engineers and much of the government research efforts are focused on understanding the attributes and characteristics that emerge from the interactions of components and subsystems. As a result, the objective of...
The reliability and survivability of a wave energy converter (WEC) is highly dependent on the variability and non-linearity of the ocean itself. Ocean variability occurs on many time scales. Climate variability occurs decade-to-decade, and year-to-year in the number and intensity of winter storms. Seasonal variation of wave height and period...
The application of lean to new product development (NPD) processes has been claimed to generate positive impact on NPD performance. There are very few empirical studies, however, on how organizations should apply lean practices or on the exact nature of the impact of lean on NPD performance. To further understand...
The objective of this study is to propose control strategies for legged robots to walk and run naturally like humans and animals. To achieve this goal, we use the spring-mass model for the legged robots to be able to create the same dynamics in the leg as humans and animals....
Bipedal locomotion is a complex phenomenon to understand and control, making it difficult for legged robots to achieve the speed, agility, efficiency, and robustness of their animal counterparts. This thesis argues for the use of numerical optimization to investigate and implement bipedal control as it applies to biology, dynamical models,...
Improving the understanding the relations of sustainability behaviors in manufacturing systems and actively engaging with manufacturers (especially SMEs) in sustainability efforts is key to the long-term success of U.S. industry and the natural environment. This study addresses this urgent need by establishing a systemic approach for the design of costing...