Wave dispersion and fracture are phenomena that involve. mechanisms triggered at the scale of a material's internal structure. Experiments were performed with a candidate material to judge the hypothesis that wave dispersion measurements can be used to nondestructively predict fracture strength. Wood-based particleboard was chosen as the candidate material because...
Recently, fiber-reinforced plastics (FRP lamina) have
been applied to glued-laminated (glulam) timber for the
purpose of improving bending strength and stiffness.
Initially, full length reinforcement using FRP lamina was
developed. However, the cost of FRP lamina is a significant
portion of the total cost of reinforced glulam. Therefore,
it is...
The Oregon State University (OSU) Advanced Plant Experiment (APEX) is a one-fourth height, one-half time scale, reduced pressure integral systems test facility designed to model the long-term cooling capabilities of the emergency core cooling systems of the Westinghouse AP600. This study provides a brief description of the APEX test facility,...
A hypothesis used to explain the relationship between timber harvesting
and landslides is that tree roots add mechanical support to soil, thus increasing
soil strength. Upon harvest, the tree roots decay which reduces soil strength and
increases the risk of management -induced landslides. The technical literature
does not adequately support...
The phenomena of interest in this work is the thermal stratification which occurs during the early stages of a loss of coolant accident (LOCA) in the OSU APEX Thermal Hydraulic Test Facility, which is a scaled model of the Westinghouse AP600 nuclear power plant. Thermal stratification has been linked to...
The primary goal of any model is to emulate, as closely as possible, the desired behavioral phenomena of the real system but still maintain some tangible qualities between the parameters of the model and the system response. In keeping with this directive, models by their very nature migrate towards increasing...
This study investigates the atmospheric flight dynamics of a munition system and the effect of a tether reel resistance mechanism for limiting the impact that the unreeling process has on the munition system. The munition system consisting of two projectiles connected by a tether line is released from an aircraft...
Eighteen Ponderosa Pine (Pinus ponderosa Dougl.ex.laws) veneer flitches
were randomly selected and crosscut into paired flitches. Serpentine-end-matched
(SEM) joints were machined in the flitches, joint amplitude equal to the width in
one half of the paired flitch and joint amplitude equal to 2/3 width in the other half
of the...
Micro-fluid mixing is an important aspect of many of the various micro-fluidic systems used in biochemical production, biomedical industries, micro-energy systems and some electronic devices. Typically, because of size constraints and laminar flow conditions, different fluids may only have the opportunity to mix by diffusion, which is extremely rate limited....
Cavitation instabilities in elastic-plastic solids under spherically-symmetric and axisymmetric loadings were investigated using the finite element method. Both quasi-static and dynamic analyses were used to solve these problems. In the quasi-static analyses, we investigated a cavitation instability in elastic/perfectly-plastic, linear hardening elastic-plastic, power hardening elasticplastic, and constrained silver materials. Here,...
Droplet formation in inkjet cartridges has been studied for several decades to improve print qualities. Currents and rigid nozzle plates are used inside the cartridge to fix the size of droplets exiting the chamber. This research is focused on studying the effect of nozzle flexibility on droplet formation. A flexible...
A particle image velocimetry system was established to determine flow fields in low Reynolds number flows through a branching flow network. Due to the fabrication procedure of the test device, flows were limited to a Reynolds number of 1.5 in the largest channel. Data was acquired at each channel inlet,...
Droplet formation from a rigid and a vibration nozzle driven by a pulsing pressure is simulated. Droplet formation is simulated by using one-dimensional model. For the case of droplet formation from a vibration nozzle, the nozzle vibration is simulated by large deflection plate vibration equation. Droplet formation from a rigid...
The use of a permeable membrane to mechanically constrain a film of water with an area of 12 cm² and a thickness of 150 μm in a gas/liquid contactor was investigated. The membrane separated the vapor and liquid phases, and a stiffener
plate made from a gas-permeable material was used...
The focus of this study is the effective prioritization of customer requirements in collaborative product development. The CR priorities are often retrieved by questioning and interviewing targeted customers. But the targeted customer might not always be easily questioned, because they might not always be obvious or clearly known. If customers...
Launch uncertainties in uncontrolled direct fire projectiles can lead to significant impact point dispersion, even at relatively short range. A model predictive control scheme for direct fire projectiles is investigated to reduce impact point dispersion. The control law depends on projectile linear theory to create an approximate linear model of...
Recent studies of flow boiling within microchannels have shown high heat fluxes, leading to successful design and testing of compact heat exchangers, cooling systems for electronics and other high efficiency, miniature components. An experimental study of flow boiling of a concentrated salt solution in microchannels is presented. Experiments examined flow...
Population counts of aquatic insects are a valuable tool for monitoring the water quality of rivers and streams. However, the handling of samples in the lab for species identification is time consuming. An aquatic insect imaging device was designed as part of a system to automate aquatic insect classification and...
Research in the miniaturization of thermomechanical systems in recent years has proven to be both rewarding and challenging. Micro-scale devices have tremendous technological potential but come with a new set of design problems. One such problem is energy storage. Heat actuated systems, driven primarily by thermal energy, take advantage of...
With growing concerns on environment impact of industrial product development, the product developers are seeking better solutions to achieve desired environmental benign requirements by the regulators and customers besides economic growth. During the last decade, some of the most successful product development companies (such as HP) have established their own...
The transfer of air travelers with disabilities between a mobility aid and an aircraft seat is a major source of injury for both the travelers and the airline personnel assisting in the transfer. The risk to both parties might be reduced through the biomechanical study of the transfer task. Such...
Infrared (IR) thermography is applied to estimate heat transfer rates in external and internal microscale convective flows. The technique and analysis are developed in the context of external jet impingement flow and internal single-phase liquid flows. A heated-thin-foil thermography technique is applied to perform surface temperature visualization on a submerged...
Sawmills are very complex systems that involve many manufacturing processes. The variability of their raw material adds further to this complexity as each log has characteristics that determine its processing path. Therefore, computer simulation is a very useful technique for analyzing sawmill performance. This thesis describes a simulation computer model...
A sawmill is similar to other manufacturing enterprises when it comes to making decisions, scheduling production and meeting customer demands. In order to help sawmills achieve their goals, and because there is such a high degree of variability in the raw material used in this industry, computer simulation has proven...
A reduced-order dynamic model is derived that captures the primary dynamics of a jet-in-crossflow. This is significant progress toward the end goal of reduced order model based closed-loop flow control. The reduced order model is a set of differential equations obtained through the use of snapshot based Proper Orthogonal Decomposition...
Jets in crossflow are used in a wide range of engineering applications and have been studied for more than 60 years. The transversal penetration and structure of a jet placed in a crossflow is known to be strongly three-dimensional. It is believed that, by using a pulsed jet inclined in...
Two-phase flow in a fractal-like branching microchannel heat sink may have
enhanced heat transfer capabilities over single phase flow in the same branching
channel network. In order to exploit this potential, a complete understanding
of flow boiling in this geometry is required. The fractal-like geometry is similar
to that of...
Microscale fluid processes are an increasingly important subgroup of fluid mechanics. Applications for heat transfer and micro-electro-mechanical devices use flows on the scale of less than one hundred microns. This study is part of a larger work in which a multiphase, high shear environment is studied in a microchannel that...
An experimental investigation into the behavior of micro-bubbles flowing
through a micro-channel has been conducted. Experiments were performed within a
rectangular micro-channel with dimensions of 5 cm x 13.2 mm x l30 jim. Bubbles
were generated in an electrolyte solution by electrolysis at the lower channel wall near
the inlet....
An experimental study was performed in which an ammonia-water solution was desorbed within a branching fractal-like microchannel array. The solution entered in the center of a disk, and flowed out radially until discharging in to a gravity-driven separation chamber. Heat was added to the ammonia-water through a thin wall, above...
A unique channel surface enhancement technique via diffusion-bonding a layer of conductive fine wire mesh onto the heating wall was developed and used to experimentally study flow boiling enhancement in parallel microchannels. Each channel was 1000 μm wide and 510 μm high. A dielectric working fluid, HFE 7000, was used...
A need exists to develop a non-destructive testing technique that can identify
the formation and propagation of diagonal tension cracks in conventionally
steel reinforced concrete deck girder (RCDG) highway bridges in the State of
Oregon. Such a technique could be included into a structural health
monitoring (SHM) system installed on...
With the miniaturization of microelectronics and increase of processor speeds in the last few decades, thermal management is drastically affecting overall packaging and system capabilities. Due to the special needs introduced, research focusing on microscale cooling has increased. This study combines the positive characteristics of single- and two-phase flows in...
Aquatic insect population counts can be a good indicator of the health, or water quality, of rivers and streams. Stoneflies (Plecoptera) are particularly susceptible to pollution in streams. However, today’s current method for obtaining these population counts requires biologists to examine individual specimens under a microscope for identification to the...
A distinct characteristic of legged locomotion is its periodic nature. This periodic motion, in the form of a periodic orbit, has been the target of many walking and running control strategies. The spring loaded inverted pendulum (SLIP) has become a popular model of sagittal plane locomotion, exhibiting behavior characteristic of...
Extending the flight time of an autonomous unmanned air vehicle by soaring is
considered. A suboptimal controller is developed and successful static soaring is
demonstrated with a 6 degree of freedom glider model. Altitude gain rates of between
¼ and ½ m/s are achieved with this simple implementation.
A hybrid...
The droplet formation process in the vicinity of the nozzle exit and the behavior of a spreading droplet during impingement on a smooth glass surface were studied. Two nozzle geometries were tested. The first case was a stiff stainless steel nozzle plate 0.787 mm thick. The second case was a...
An experiment was conducted to examine the possible impact of an engineering design and problem solving process overview document on knowledge management and capture. A process overview document was first created. Next, two multi-disciplinary design teams worked over a two-week span to develop concepts to address a problematic opportunity. One...
Product design is often driven by customer needs and desires. In this case the customer is the US military, and the desire is to have a cooling unit small enough and light enough to incorporate into hazard suits for use in desert combat. The Micro technology-based Energy and Chemical Systems...
It is crucial for the development of high quality products that design requirements are identified and clarified as early as possible in the design process. In many projects the design requirements and design specifications evolve during the project cycle. Shifting needs of the customer, advancing technology, market considerations and even...
Proper orthogonal decomposition (POD) in conjunction with the Galerkin projection has been used as a model reduction technique for the tractable real-time control of high-dimensional systems. While POD based model reduction may improve the tractability of high-dimensional models, the nonlinear POD based model may be impractical for control due to...
Design and preliminarily characterization of two thermally-actuated pumps is presented
in this thesis. The unique feature of both pumps is the presence of periodic asymmetrical
structures on the channel walls. Two heat transfer effects are used with surface
asymmetry to generate forces that drive the fluid in a preferential direction...
For piezoelectric stack (PZT) driven droplet generator, the driving waveform
and driving frequency effect on liquid filament shape and droplet characteristics have
been experimentally studied. The experimental study was based on a PZT driven
droplet generator with known geometric design parameters and working fluid
properties. A lumped-element-model (LEM) constructed to...
A large part of low-back pain occurrences are due to disc herniation or prolapse of the nucleus pulposus. An alternative technique to existing treatments of low back pain includes nucleus pulposus replacement by an artificial material to relieve pain and restore normal function. To date, there has been a deficiency...
People often grow increasingly culturally confused when spending significant amounts of time in a foreign land. Identity can become lost only to reform in the image of the host society. This thesis presents a creative nonfiction series of essays that explore the author’s loss of self and contextual identity, the...
An experimental study of the near-field flow structure produced by an incompressible turbulent Acoustically Self-Excited Jet (ASEJ) in a large enclosure using Particle Image Velocimetry (PIV) is presented. The salient feature of this jet is that it provides an increase in near-field mixing and turbulence without additional external power input....
It is hypothesized that increases in pressure drop due to vapor generation during boiling in microchannels can be reduced by extraction of vapor at its point of inception. Ultimately, this local vapor extraction decreases the pressure drop required to drive the flow through a fractal-like branching, microchannel flow network within...
Air travel presents several problems for passengers with disabilities.
One in particular is how they get from their wheelchair and to an aircraft seat.
The commonly used manual transfer method is hazardous to the assistants
and the passenger. There are other alternatives, but they have plenty of room
for improvement....
Oregon Department of Transportation’s bridge no. 9743b is a multi-span, two-girder steel deck bridge connecting the busy interstates 5 and 205. Vertical cracks have been detected in the welded girder-to-crossbeam connections at the bents. Distortion-induced fatigue is suspected to be responsible for the cracking. Linear elastic beam analysis, 2-D and...