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Articles 1 - 13 of 13
Full-Text Articles in Engineering
Using Single-Molecule Dna Flow-Stretching Experiments To See The Effects Of Temperature And Viscosity, Fatema Tuz Zohra
Using Single-Molecule Dna Flow-Stretching Experiments To See The Effects Of Temperature And Viscosity, Fatema Tuz Zohra
Theses and Dissertations
Deoxyribonucleic acid (DNA) is a highly charged long and semi-flexible polymer of which length is much longer than cell dimensions at least by 1,000-folds. A long linear DNA turns into a crumpled structure to fit into a tiny cell volume by the process known as DNA compaction. In nature, DNA fits into the volume of the cell using DNA compaction by packaging genome material. Various types of protein are involved in DNA compaction. To experiment with various proteins as DNA compaction agents, DNA needs to be stretched out. In our thesis, the effect of temperature and buffer viscosity on DNA …
Pressurized Combustion Product Temperature Measurement Using Integrated Spectral Band Ratios, Scott Cutler Egbert
Pressurized Combustion Product Temperature Measurement Using Integrated Spectral Band Ratios, Scott Cutler Egbert
Theses and Dissertations
With increasing global power demands, there is a growing need for the clean and efficient use of fossil fuel resources. Gas turbine engines are a commonly used means for generating power; from the propulsion of aircraft to electricity on municipal grids. Measuring the temperature within a turbine combustor or at a turbine inlet could provide numerous advantages related to engine control, durability, efficiency, and emissions and yet this relatively straightforward task has eluded turbine engine manufacturers, primarily because of the high temperatures and pressures, harsh environment, and limited access. Optical emissions measurements are of particular interest for this task as …
Impact Of Cycloalkanes On Ignition Propensity Measured As Derived Cetane Number In Multi-Component Surrogate Mixtures, Dalton Odell Carpenter
Impact Of Cycloalkanes On Ignition Propensity Measured As Derived Cetane Number In Multi-Component Surrogate Mixtures, Dalton Odell Carpenter
Theses and Dissertations
Cycloalkanes are one type of hydrocarbons present in real jet fuels. The distinct cyclic structure of the cyclo-alkanes impacts the chemical kinetic behavior differently compared to n- and iso-alkanes. At high temperatures, thermal decomposition reactions dominate, producing n-alkyl radicals similar to the oxidation reactions of n-alkanes thus promoting the reactivity. Whereas in low temperatures, the presence of the ring structure essentially suppresses the formation of alkylhydroperoxy radicals (QOOH) from alkylperoxy radicals (RO2), thus exhibiting similar reactivity to iso-alkanes. In previous generations of surrogate fuels, the cyclo-alkane functional group were largely ignored due to low levels of cycloalkanes in traditional jet …
Determining H2O Vapor Temperature And Concentration In Particle-Free And Particle-Laden Combustion Flows Using Spectral Line Emission Measurements, John Robert Tobiasson
Determining H2O Vapor Temperature And Concentration In Particle-Free And Particle-Laden Combustion Flows Using Spectral Line Emission Measurements, John Robert Tobiasson
Theses and Dissertations
There is a growing need for the clean generation of electricity in the world, and increased efficiency is one way to achieve cleaner generation. Increased efficiency may be achieved through an improved understanding of the heat flux of participating media in combustion environments. Real-time in-situ optical measurements of gas temperature and concentrations in combustion environments is needed. Optical methods do not disturb the flow characteristics and are not subject to the temperature limitation of current methods. Simpler, less-costly optical measurements than current methods would increase the ability to apply them in more circumstances. This work explores the ability to simultaneously …
Temperature Measurement Using Infrared Spectral Band Emissions From H2o, Daniel Jared Ellis
Temperature Measurement Using Infrared Spectral Band Emissions From H2o, Daniel Jared Ellis
Theses and Dissertations
Currently there is no known method for accurately measuring the temperature of the gas phase of combustion products within a solid fuel flame. The industry standard is a suction pyrometer and thermocouple which is intrusive, both spatially and temporally averaging, and difficult to use. In this work a new method utilizing the spectral emission from water vapor is investigated through modeling and experimental measurements. This method was demonstrated along a 0.75m line of sight, averaged over 1 minute in the products of a natural gas flame but has the potential to produce a spatial resolution on the order of 5 …
Development Of Novel Passive Control Techniques For More Uniform Temperature At Combustor Exit And Hybrid Les/Rans Modeling, Alka Gupta
Theses and Dissertations
Gas turbines have become an important, widespread, and reliable device in the field of power generation. For any gas turbine system, the combustor is an integral part responsible for the combustion of the fuel. A number of studies have shown that the flow field exiting a combustor is highly non-uniform in pressure, velocity and, most importantly, temperature. Hot streaks amongst other non-uniformities cause varying thermal stresses on turbine blades and put pressure on the blade materials. In particular, these non-uniformities can have detrimental effects on the performance of the engine and cause a reduction in the expected life of critical …
Application Of Two-Color Pyrometry To Characterize The Two-Dimensional Temperature And Emissivity Of Pulverized-Coal Oxy-Flames, Teri Snow Draper
Application Of Two-Color Pyrometry To Characterize The Two-Dimensional Temperature And Emissivity Of Pulverized-Coal Oxy-Flames, Teri Snow Draper
Theses and Dissertations
Oxy-combustion is a developing technology that enables carbon dioxide (CO2) capture. Flame temperature and emissivity data were taken on a 150 kWth, pulverized-coal, burner flow reactor (BFR) that has been modified to run oxy-combustion with pure CO2 as simulated recycled flue gas. Data were taken at 78 conditions in which three parameters were varied, namely: the swirl angle of the fuel stream, the location of the oxidizer as it exited the burner, and the flow rate of diluent (pure CO2) added to the outer, secondary stream. At each condition, digital color images were obtained using a calibrated RGB camera. The …
Investigation And Implementation Of A Robust Temperature Control Algorithm For Friction Stir Welding, Kenneth A. Ross
Investigation And Implementation Of A Robust Temperature Control Algorithm For Friction Stir Welding, Kenneth A. Ross
Theses and Dissertations
In friction stir welding, the temperature of the process zone affects the properties of the resulting weld and has a dramatic effect on tool life in PCBN (polycrystalline cubic boron nitride) tools. Therefore an active control system that changes process parameters to control weld temperature is desirable. Mayfield and Sorensen proposed a two-stage control model that contains an inner loop that controls the spindle speed to keep power constant and an outer loop for setting the desired power based on weld temperature. This work contains the analysis and implementation of a temperature control method based on their work. This research …
Characterization And Biomechanical Analysis Of The Human Lumbar Spine With In Vitro Testing Conditions, Dean K. Stolworthy
Characterization And Biomechanical Analysis Of The Human Lumbar Spine With In Vitro Testing Conditions, Dean K. Stolworthy
Theses and Dissertations
Biomechanical testing of cadaveric spinal segments forms the basis for our current understanding of healthy, pathological, and surgically treated spinal function. Over the past 40 years there has been a substantial amount of data published based on a spinal biomechanical testing regimen known as the flexibility method. This data has provided valuable clinical insights that have shaped our understanding of low back pain and its treatments. Virtually all previous lumbar spinal flexibility testing has been performed at room temperature, under very low motion rates, without the presence of a compressive follower-load to simulate upper body weight and the action of …
Fiber Optic Sensor Interrogation Advancements For Research And Industrial Use, Wesley Mont Kunzler
Fiber Optic Sensor Interrogation Advancements For Research And Industrial Use, Wesley Mont Kunzler
Theses and Dissertations
Spectrally-based fiber optic sensors are a rapidly maturing technology capable of sensing several environmental parameters in environments that are unfitting to electrical sensors. However, the sensor interrogation systems for this type of sensors are not yet fit to replace conventional sensor systems. They lack the speed, compact size, and usability necessary to move into mainstream test and measurement. The Fiber Sensor Integrated Monitor (FSIM) technology leverages rapid optical components and parallel hardware architecture to move these sensors across the research threshold into greater mainstream use. By dramatically increasing speed, shrinking size, and targeting an interface that can be used in …
Sensitivity Of Half-Cell Potential Measurements To Properties Of Concrete Bridge Decks, Thad Marshall Pinkerton
Sensitivity Of Half-Cell Potential Measurements To Properties Of Concrete Bridge Decks, Thad Marshall Pinkerton
Theses and Dissertations
Half-cell potential testing has been recommended as a non-destructive method for assessing the corrosion potential of reinforcing steel in concrete bridge decks. The technique is particularly useful because it can be utilized to evaluate the probability of corrosion before damage is evident at the surface of a bridge deck. The specific objective of this research was to quantify the effects of age, chloride concentration, concrete cover thickness, spatial position, temperature, and presence or condition of epoxy coating on half-cell potential measurements of concrete bridge decks typical of those in Utah. The laboratory testing associated with this research followed a full-factorial …
Polarimetric Temperature Sensor Using Core-Replaced Fiber, Benjamin L. Ipson
Polarimetric Temperature Sensor Using Core-Replaced Fiber, Benjamin L. Ipson
Theses and Dissertations
Optical fibers are increasingly being used to create sensing devices. The D-fiber has an elliptical core and exhibits birefringence. This birefringence can be used to create a polarimetric sensor. The elliptical core supports two orthogonal modes that have separate effective indices of refraction. The indices of refraction change with a change in temperature. Since the effective indices of refraction change differently for the two modes, the birefringence also changes. This change in birefringence can be seen as a change in detected power through the fiber through the use of polarizers. The fiber then becomes a temperature sensor. The sensitivity of …
Effects Of Liquid Transpiration Cooling On Heat Transfer To The Diverging Region Of A Porous-Walled Nozzle, Daniel J. Schieb
Effects Of Liquid Transpiration Cooling On Heat Transfer To The Diverging Region Of A Porous-Walled Nozzle, Daniel J. Schieb
Theses and Dissertations
This research effort investigated the effects of evaporation of water on the heat transferred to the wall of the diverging portion of a porous walled nozzle The AFIT High Pressure Shock Tube was used with a two-dimensional Mach 3 nozzle. One flat surface of the nozzle was fitted with a layer of porous stainless steel from the nozzle throat to the exit. This porous material was saturated with water to simulate liquid transpiration cooling. Surface temperature data was taken in this region using fast response coaxial thermocouple. Heat transfer was determined from the surface temperature history. Data was taken for …