Describing functions have traditionally been used to obtain the
solutions of systems of ordinary differential equations. In this
work the describing function concept has been extended to include
nonlinear, distributed parameter partial differential equations. A
three-stage solution algorithm is presented which can be applied to
any nonlinear partial differential equation....
A mathematical model of a differential thermal analysis (DTA)
system was formulated so that influence of the various physical parameters
on the DTA peak could be determined. The specific DTA apparatus
simulated had cylindrical sample holes drilled into a nickel
block considered to have a negligible thermal resistance, and the...
Pure aluminum deformed in torsion (shear) at elevated temperatures reaches
a broad "peak" stress and then undergoes about a 17% decrease in flow stress with
deformation to roughly 1-2 equivalent uniaxial strain. Beyond this strain the flow
stress is approximately constant. The sources for this softening are unclear. The
suggested...
In this thesis we consider boundary and initial value problems
associated with the melting of homogeneous cylinders and
spheres. The study includes the temperature distribution in cylinders
and spheres which are perfectly insulated at the surface and
subjected to a heat input respectively along the axis and at the
center....
A phase sensitive measurement technique that permits the simultaneous determination
of two independent thermal properties of thin dielectric films is presented. Applying the technique results in a film's thermal diffusivity and effusivity, from which the thermal conductivity and specific heat can be calculated. The technique involves measuring a specimen's front...
The quality of a digital image pipeline relies greatly on its color reproduction which should at a minimum handle the color constancy, and the final judgment of the excellence of the pipeline is made through subjective observations by humans.
This dissertation addresses a few topics surrounding the color processing of...
Five Ultra light Fabric Reflux Tubes (UFRTs) were tested in a thermal vacuum chamber at the National Aeronautics and Space Administration's Johnson Space Center in September 1994. These test articles were design and fabricated by staff at the Pacific Northwest Laboratory, operated by Battelle Memorial Institute for the United States...
Nearly fifty years after the introduction of skew Brownian motion by Itô and
McKean (1963), the first passage time distribution remains unknown. In this
paper, we first generalize results of Pitman and Yor (2001) and Csáki and Hu
(2004) to derive formulae for the distribution of ranked excursion heights of...
An analytical solution is developed for the temperature
profile of a unit cell consisting of a sphere of one
material centered in a cube of a second material. All
material properties are considered constant and boundary
conditions consist of specified temperatures on the top
and bottom faces of the cube...
With the continued decrease in size and subsequent increase in power of computer processors, thermal management in electronics is becoming more important than ever before. The chip heat densities are reaching new peaks (> 100 W cm-2) that current cooling methods are not able to keep up with. However, some...
A cooling tower system was built and fouling resistances were
studied for cooling water flowing over a heated tubular surface. The
cooling water studied was formulated in an effort to match industrial
cooling water quality. The water used in this study had an average
Ryznar Stability Index of 6.23 and...
This research presents an analysis of thermal stratification in the reactor cold leg of the Advanced Plant Experiment-Combustion Engineering (APEX-CE). This phenomenon may be a precursor leading to a Pressurized Thermal Shock (PTS) event in a nuclear power plant. This work was performed in support of the U.S. Nuclear Regulatory...
This publication is the third in a series of circulars de signed to assist the graduate engineer in reviewing engineering subject matter in order to prepare for registration examinations. As in the first publication of the series, most of the illustrative problems are taken from recent examinations of the Oregon...
Among recently found multi-component Zr-based bulk metallic glasses (BMG), Zr₅₈.₅Cu₁₅.₆Ni₁₂.₈Al₁₀.₃Nb₂.₈ is characterized by its lower critical cooling rate requirement and absence of beryllium as one of the constituent element which makes its handling more convenient. Its large supercooled liquid regions made possible the study of thermodynamics and kinetics of this...
By the investigation of the bulk metallic glass-forming liquids that have very low critical cooling rates, the thermodynamics of metallic glasses can be clarified. For studying thermodynamic properties, such as the specific heat capacity, calorimetry (DSC) is utilized and one of the most used instruments is the differential scanning calorimeter....
The heating rate dependence of the glass transition temperature of the
Ni₆₅Nb₃₅, Ni₆₀Nb₃₅Sn₅, Ni₅₉.₃₅Nb₃₄.₄₅Sn62, Ni₆₀(Nb₄₀Ta₆₀)₃₄Sn₆, and
Ni₅₇Fe₃Nb₃₅Sn₅ metallic glass forming alloys was investigated with a
differential scanning calorimeter (DSC). The inverse heating rate for each
DSC experiment was plotted versus inverse temperature and a Vogel-Fulcher-
Tamman (VFT) type relation was...
The thermal contact conductance (TCC) between two machined pieces of stainless steel was studied. A guarded hot plate thermal conductivity test fixture was designed and built for the experiment. Factors investigated included the contact pressure, surface roughness, interface material and average test temperature. The contact pressure at the interface ranged...
Zirconium press plates have been developed for the production of melamine coated particle board, using shot-peening to achieve the desired plate (and therefore coated particle board) surface texture. Service temperatures of the press plates approach 200°C. This study examined the microstructural effects of extended exposure of shot-peened zirconium to temperatures...
At the College of Engineering, Oregon State University, we have successfully developed and demonstrated a distance learning application utilizing emerging communications technologies in a new way to allow control engineering teaching laboratories to be accessed remotely. Second Best to Being There (SBBT) provides the remote user with all the capabilities...
Industrial Engineering is a broad discipline, with a wide range of definitions for the field and the knowledge areas that make up its parts. A conceptual gap exists between the definition of the field of Industrial Engineering and the definitions of each of these parts. To facilitate advancement of the...
Reflux condensation tests examining steam condensation in a PWR steam
generator (SG) were conducted at the Oregon State University (OSU) Advanced
Plant Experiment (APEX) Test Facility from 2005 through 2007. The
experimental data collected will provide a basis to assess TRACE steam generator
modeling techniques and assist in development of...
Full Text:
THE THESIS OF
Brian A. Collins for the degree of Master of Science in Nuclear Engineering
The finite difference time domain (FDTD) method was used to model anti-reflective properties of a variety of sub-wavelength structures for 300 to 1300 nm input light. Light hitting non-tapered nanostructures exhibited interference patterns similar to thin film anti-reflective coatings (ARCs), increasing the anti-reflective effect at several wavelengths. The lowest reflectance...
Finite-difference time-domain simulations are performed on a 900 MHz band antenna inside and outside the carbon fiber body of a solar-powered electric vehicle. Data are analyzed to determine the optimal antenna placement for transmission to a receiving antenna located toward the rear of the solar vehicle. Modeling data are compared...
When trace quantities of an alkali element are added to a flame,
its optical and electrical properties change significantly. Addition of
alkali seed to both premixed and diffusion flames has been used in the
development of two new techniques, one for flame temperature measurement
and the other for enhanced mixing....
Improved methods of determining temperature transients in reactor systems are desired because of recent interest in Pressurized Thermal Shock (PTS) issues. The research presented herein was performed in support of the Nuclear Regulatory Commission's effort to re-evaluate its existing PTS rules. These rules are particularly important to the re-licensing of...
Non-destructive testing is a methodology to inspect production and operational parts for potential flaws, defects, or damages. The present work is based on pulsed wave thermography, a thermal imaging method based on heat conduction to identify surface and subsurface defects potentially present in a component. Pulsed wave thermography applies a...
An important element in rector safety and fuel performance assessments is the efficient calculation of the time dependent temperature profiles within reactor fuel pins. Because the fuel pins have temperature dependent thermal properties, the governing partial differential equations are nonlinear. Traditionally, finite difference or finite element methods have been used...
In the present work, a correlation is made between seismic intensity parameters and total damage indicators of reinforced concrete structures. For this purpose, natural ground motions recordings were used, from which intensity measures were calculated and alternatives were proposed. Then, through dynamic inelastic time history analyzes, damage indices were evaluated...
When large disturbances occur in interconnected power systems, there exists the danger
that the power system states may leave an associated region of stability, if timely corrective action
is not taken. Open-loop remedial control actions such as field-forcing, line-tripping, switching of
series-capacitors, energizing braking resistors, etc., are helpful in reducing...
Amorphous multicomponent metals have promising applications in novel electronic devices because of their atomically smooth surface morphology and lack of grain boundaries. It is important to understand the thermal transport properties of amorphous metals and an accurate measurement of their thermal conductivity will be essential for further improvement of device...
Calls for reform within engineering education frequently cite the need to better prepare the future workforce for the imminent challenges that they will face. The focus in preparing students for the workforce is often on the educational system and not on understanding the actual workplace. But if we are to...
A numerical model has been developed to simulate the firing of an inkjet printhead.
The model evaluates the heat generation and diffusion within the thin film structure, the
phase change and vapor bubble growth in the ink, and the subsequent flow of ink from the
orifice. The heat transfer is...
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...
A high temperature high vacuum rheometer has been designed, fabricated,
and tested for the study of the steady shear viscosity for multicomponent bulk
metallic glass forming alloys. This rheometer has an operating range up to
1525 K, rotational frequencies of 9.4*10⁻³-3.7*10¹ radians/s, and a
calibrated viscosity range of 9.6*10⁻³ and...
The defect mechanisms that underpin the high energy density dielectric 0.8BaTiO₃–0.2Bi(Zn₁/₂Ti₁/₂) O₃
were investigated. Characterization of the nominally stoichiometric composition revealed the
presence of a Ti³⁺-related defect center, which is correlated with lower resistivities and an
electrically heterogeneous microstructure. In compositions with 2 mol. % Ba-deficiency, a barium
vacancy-oxygen vacancy...
Full Text:
Science, School of Mechanical, Industrial, and Manufacturing Engineering,
Oregon State University
Thermoelectric materials are playing an increasingly significant role in the global effort to develop sustainable energy technologies. Consequently, the demand for materials with greater thermoelectric efficiency has stimulated the development of state-of-the-art interstitially doped skutterudite-based materials. However, since intermetallics are often embrittled by interstitial substitution, optimal skutterudite-based device design, manufacture,...
A constrained thin film desorption scheme has been experimentally tested to determine the desorption rates for water from an aqueous lithium bromide mixture through a confining membrane. Variable conditions include the inlet concentration, pressure differential across the membrane, and channel height. Desorption takes place in a channel created between two...
This report establishes an industry knowledge base for existing anchoring and mooring techniques as applied to wave energy conversion (WEC) devices in and around Oregon. This report on anchoring and mooring techniques is derived from the cumulative experiences of engineers and scientists with many years of experience analyzing, designing and...
Nisin, an antimicrobial peptide used in food preservation was
evaluated for thermal stability. Nisin retained antimicrobial
activity after having been heated at 121°C for seven hours.
Anhydrous nisin and concentrated nisin solutions (5-10 mg/ml) were
still active after having been heated up to 190°C or 230°C. When
exposed to high...
In light of the current world-wide energy situation,
the utilization of the immense reserves of geothermal
energy is being actively pursued. The thermal energy contained
in a geothermal reservoir is mainly stored in rocks,
but is also held in liquid water and/or steam. The generation
of electrical power from these...
The thermal wave technique has been explored for the use of liquid thermal conductivity measurement and flow property diagnostics in this dissertation. For liquid thermal conductivity measurements, an experimental technique based on the thermal wave approach is developed. A stainless steel strip functions as both a heating element and a...
Electroluminesence (EL) thermal quenching refers a reduction in luminance, concomitant with a reduction in transferred charge, when an alternating-current thin-film electroluminescent (ACTFEL) device is operated at an elevated temperature. EL thermal quenching is found to be significant in SrS:Cu ACTFEL devices operated above ~60-80 °C. Maximum transferred charge-maximum applied voltage...
Thermal diffusivity of snow is an important thermodynamic property associated with key hydrological phenomena such as snow melt and heat and water vapor exchange with the atmosphere. Direct determination of snow thermal diffusivity requires coupled point measurements of thermal conductivity and density, which are nonstationary due to snow metamorphism. Traditional...
We measure the thermal conductivities of nano-grained strontium titanate (ng-SrTiO₃) films deposited on sapphire substrates via time-domain thermoreflectance. The 170 nm thick oxide films of varying grain-size were prepared from a chemical solution deposition process. We find that the thermal conductivity of ng-SrTiO₃ decreases with decreasing average grain size and attribute...
The fundamental physics of turbulence in plasma is not well understood. Recent studies of the plasma deflagration accelerator in the High Temperature Gasdynamics Lab at Stanford University have demonstrated the presence of small scale instabilities that limit the lifetime of the jet/Z pinch and are not reproduced by coaxial plasma...
The research undertaken in this study deals with three topics related to the prediction of thermodynamic properties of electrolytes in aqueous solutions. In the first, Pitzer ion interaction parameters for 304 single electrolytes were evaluated from recently published osmotic coefficient data at 25°C by using multiple regression analysis to fit...
For over 30 years, the Implicit Monte Carlo (IMC) method has been used to
solve challenging problems in thermal radiative transfer. These problems are typically optically thick and di ffusive, as a consequence of the high degree of "pseudo-scattering" introduced to model the absorption and reemission of photons from a...
Amorphous metal thin films (AMTFs) are of potential use for metal-insulator-metal (MIM) tunnel diode applications due to their ultra-smooth surfaces, a consequence of their amorphous microstructure. The objective of this thesis is to design a thermally-stable AMTF capable of maintaining MIM tunnel diode performance after a post-deposition anneal in excess...
A theoretical study of the heat and momentum transfer resulting
from a flow of power plant condenser effluent discharged vertically to
shallow, quiescent coastal receiving water is presented. The complete
partial differential equations governing steady, incompressible, turbulent
flow driven by both initial momentum and buoyancy are solved
using finite-difference techniques...
Two framework oxide materials of the MO₃ network type have been synthesized and structurally characterized by synchrotron and X-ray powder diffraction and the Rietveld method in the temperature range 25~500 K. The results show one of them to be a low thermal expansion material. Theoretical studies of negative thermal expansion...
Increased competition in the market place for both occasional and professional chain saw users has led to a desire for improved performance in chain saw guide bars. One aspect of improved performance is lower bar weight. The primary focus of this research was to establish the feasibility of a lower...
A novel thermal management approach is explored, which uses supercritical carbon dioxide (sCO2) as a working fluid to manage extreme heat fluxes in electronics cooling applications. In the pseudocritical region, sCO2 has extremely high volumetric thermal capacity, which can enable operation with low pumping requirements, and without the potential for...
In this thesis, I conduct an analysis of paradigmatic background assumptions deployed in engineering decision-making processes, in order to understand how these assumptions, operating tacitly and in tension with each other, contribute to decisions that are ethically less effective and less substantial than they would otherwise be. I do so...
The low temperature geothermal resource at Klamath Falls,
Oregon is widely used for heating buildings. A common technique
for using this resource consists of a heat exchanger down in the
well inside a casing which extends the full length of the well.
Slots are cut in the casing to allow...
Thermal cracking of asphalt concrete pavements is responsible for millions
of dollars in annual maintenance and rehabilitation costs in the United States and
Canada. Thermal cracking is typically associated with low temperatures in
northern climates and at high elevations. However, another form of thermal
cracking, known as thermal fatigue cracking,...
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...
Natural freshwater availability is decreasing as the global population increases. Advances in desalination technologies aim to produce fresh water in an economical way. More sustainable energy sources are desired for these desalination plants to limit the carbon footprint of water production since global carbon dioxide production is exacerbating freshwater scarcity....
Desalination stands for removing salt from saline water, and produce freshwater. Desalination technologies have been envisioned as a potential solution for freshwater production from oceans as an immense source of water acquiring 97% earth’s water, and 75% of earth’s surface. However, one third of world’s population face water scarcity every...
The thermal decomposition of tungsten hexacarbonyl was
investigated in an apparatus which allowed a solid sample of the material
to be sealed into a preheated batch reactor. Because the reaction occurs
with an increase in the number of moles of gas, it was possible to monitor
the progress of the...
The 13th Annual Northwest Traffic Engineering Conference and the 1960 Annual Northwest Road Building Conference this year have been combined to give a broader concept of the field of highway engineering to persons interested in both phases. Future conferences will alternate as before between the States of Washington and Oregon....
This thesis reports on an investigation of flow patterns in
shallow geothermal wells in Klamath Falls, Oregon, Although
wells have been extensively used in the area, the exact nature of
the flows in the wells has not been characterized.
Flow characterization is a principal object of this study.
Horizontal crossflows...
The nonlinear dynamic analysis of cable and cable-large
body systems subject to both deterministic and non-deterministic
loading is presented in this study. Nonlinearities
occur due to large displacements, material nonlinearity,
lack of stiffness in compression, and the non-conservative
fluid loading.
A finite element model is used to model the cable...
Due to a lack of grain boundaries, an amorphous metal thin film (AMTF) possesses advantageous mechanical properties and enhanced chemical stability that is potentially useful for thermal inkjet (TIJ) printing applications. The use of an AMTF as a TIJ resistor or cavitation plate could lead to a thinner TIJ cavitation...
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...
Flow rate sensors for in situ gas or liquid monitoring typically comprise multiple transducer elements, including a heater and one or more temperature sensors to measure the rate of heat energy removal by the flowing fluid. The need for multiple transducer elements limits feasibility of shrinking these sensors to microfluidic...
Cyanobacteria inhabit nearly every ecosystem on earth, play a vital role in nutrient cycling, and are
useful as model organisms for fundamental research in photosynthesis and carbon and nitrogen fixation.
In addition, they are important for several established biotechnologies for producing food additives,
nutritional and pharmaceutical compounds, and pigments, as...
This circular describes research activities of the Oregon State College School of Engineering during the school years 1958-59 and 1959-60. These activities are listed according to the engineering department in which the research is carried out. In each department section are described facilities of the department, research projects, and graduate...
Clean cooking technologies and fuels have been cited as a viable way to slow climate change and reduce the health and environmental impacts associated with traditional cooking devices used by 40% of the world. While engineers in the Design for Development sector have created hundreds of stove designs that perform...
The solution of coupled neutronic/thermal hydraulic nuclear reactor calculations
requires the treatment of the nonlinear feedback induced by the thermal hydraulic
dependence of the neutron cross sections. As a result of these nonlinearities, current
solution techniques often diverge during the iteration process. These instabilities arise
due to the low level...
The Boltzmann transport equation derived in the Self-Adjoint Angular Flux (SAAF) formulation is applied to simulate phonon transport. The neutron transport code Rattlesnake is leveraged in this fashion, slightly modi ed to accept input from variables consistent with phonon transport simulations. Several benchmark problems are modeled to assess the potential...
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...
The increasing demand for forest products and restricted use of natural forests has resulted in a shortage of high-strength wood fiber. The area covered by plantation forests is steadily rising, but the fiber produced by these forests is often unsuitable for high-strength applications. One attempt to combat this problem is...
The defect mechanisms that underpin the high energy density dielectric 0.8BaTiO₃–0.2Bi(Zn₁/₂Ti₁/₂) O₃ were investigated. Characterization of the nominally stoichiometric composition revealed the presence of a Ti³⁺-related defect center, which is correlated with lower resistivities and an electrically heterogeneous microstructure. In compositions with 2 mol. % Ba-deficiency, a barium vacancy-oxygen vacancy...
Summarizes information on wood as an engineering material.
Presents properties of wood and wood-based products
of particular concern to the architect and engineer. Includes
discussion of designing with wood and wood-based products
along with some pertinent uses.