+publisher:"Penn State University" +contributor:("Albert Eliot Segall, Committee Member")

Penn State University

1. Suprock, Andrew David. AN INVESTIGATION INTO THE TEMPERATURE EFFECT ON THE PERFORMANCE OF ULTRASONIC TRANSDUCERS FOR HIGH TEMPERATURE AND HARSH ENVIRONMENT APPLICATIONS.

Degree: 2016, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/13134ads303

► Transducer technology is an in-demand resource particularly in the fields of ultrasonic non-destructive evaluation (UNDE), structural health monitoring (SHM), and biomedical ultrasound. For years, transducers… (more)

▼ Transducer technology is an in-demand resource particularly in the fields of ultrasonic non-destructive evaluation (UNDE), structural health monitoring (SHM), and biomedical ultrasound. For years, transducers have been used to characterize various types of materials, ranging from metals to composites (interwoven conglomeration of various materials) and even organics as well as to establish the integrity of structural components such as bridge struts, subterranean pipelines, and vehicle bodies. Transducers can even be used to find defects, cracks, delaminations, etc on the micro- and nano-scales. Most of these processes occur at room temperature or only slightly elevated temperatures (<100 °C). This means that the physical components have little to fear from the stress and strain of thermal expansion as well as the process of oxidation. However, when higher temperature (>400 °C) capabilities are necessary, only a select few piezoelectric materials can make the cut. The piezoelectric material must be combined with the right components from the casing, to the waveguide, to the coupling, to the matching layer, as well as the backing material and work together cohesively with a lead wire to produce the most consistent and cleanest acoustic signals and data possible for their particular application. The objective of this thesis is to investigate the influence of the temperature effect on ultrasonic transducers based on a comparison of the effects of high temperature conditions versus those of high temperature and irradiation on the transducer system. There will also be a preliminary move towards the establishment of the means for optimizing the bulk single crystal transducer fabrication process in order to achieve peak efficiency and maximum effectiveness in both irradiated and non-irradiated high temperature applications. Optimization of the material components within the transducer will greatly increase non-destructive testing abilities for industry, structural health monitoring, and so much more. The following research involves testing several different piezoelectric materials under high temperature conditions. The viability of aluminum nitride (AlN) as a transducer material in high temperature conditions has been previously explored [1] (Parks, et al, 2010) and shall be further tested to ensure reliability. Zinc oxide (ZnO) and bismuth titanate (BiT) will also be explored as they have shown promising results in the past. Data collected from the ULtrasonic TRAnsducers (ULTRA) project will also be compared to the high temperature data since the construction of the transducer was the same. A preliminary search of various combinations of transducer material components (waveguide and backing materials in order to find the best match for a given piezoelectric material) will be conducted to find the best combination of these components for steady and strong acoustic transmission. Advisors/Committee Members: Bernhard R Tittmann, Thesis Advisor/Co-Advisor, Albert Eliot Segall, Committee Member, Clifford Jesse Lissenden III, Committee Member.

Subjects/Keywords: Ultrasonic Non-Destructive Evaluation; Structural Health Monitoring; Ultrasonic Transducers; High Temperature; Harsh Environment; Radiation; Materials Optimization; NDE; SHM; Piezoelectricity; Piezoelectric Materials; Piezoelectric Crystal Structures

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APA (6^th Edition):

Suprock, A. D. (2016). AN INVESTIGATION INTO THE TEMPERATURE EFFECT ON THE PERFORMANCE OF ULTRASONIC TRANSDUCERS FOR HIGH TEMPERATURE AND HARSH ENVIRONMENT APPLICATIONS. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/13134ads303

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Suprock, Andrew David. “AN INVESTIGATION INTO THE TEMPERATURE EFFECT ON THE PERFORMANCE OF ULTRASONIC TRANSDUCERS FOR HIGH TEMPERATURE AND HARSH ENVIRONMENT APPLICATIONS.” 2016. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/13134ads303.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Suprock, Andrew David. “AN INVESTIGATION INTO THE TEMPERATURE EFFECT ON THE PERFORMANCE OF ULTRASONIC TRANSDUCERS FOR HIGH TEMPERATURE AND HARSH ENVIRONMENT APPLICATIONS.” 2016. Web. 22 Jan 2021.

Vancouver:

Suprock AD. AN INVESTIGATION INTO THE TEMPERATURE EFFECT ON THE PERFORMANCE OF ULTRASONIC TRANSDUCERS FOR HIGH TEMPERATURE AND HARSH ENVIRONMENT APPLICATIONS. [Internet] [Thesis]. Penn State University; 2016. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/13134ads303.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Suprock AD. AN INVESTIGATION INTO THE TEMPERATURE EFFECT ON THE PERFORMANCE OF ULTRASONIC TRANSDUCERS FOR HIGH TEMPERATURE AND HARSH ENVIRONMENT APPLICATIONS. [Thesis]. Penn State University; 2016. Available from: https://submit-etda.libraries.psu.edu/catalog/13134ads303

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

2. Zhang, Zhifeng. Virtual Entropy Generation.

Degree: 2017, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/14319zjz5083

► The real world is not perfect. So are equations and measurements. In the real world, the first law of thermodynamics is balanced by an error… (more)

Subjects/Keywords: Virtual entropy generation; Reliablity and uncertainty control; Second-Law of thermodynamics; Heat exchanger

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APA (6^th Edition):

Zhang, Z. (2017). Virtual Entropy Generation. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/14319zjz5083

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Zhang, Zhifeng. “Virtual Entropy Generation.” 2017. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/14319zjz5083.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Zhang, Zhifeng. “Virtual Entropy Generation.” 2017. Web. 22 Jan 2021.

Vancouver:

Zhang Z. Virtual Entropy Generation. [Internet] [Thesis]. Penn State University; 2017. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/14319zjz5083.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Zhang Z. Virtual Entropy Generation. [Thesis]. Penn State University; 2017. Available from: https://submit-etda.libraries.psu.edu/catalog/14319zjz5083

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

3. Reinhardt, Brian T. Nonlinear ultrasonic measurements in nuclear reactor environments.

Degree: 2016, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/28985

► Several Department of Energy Office of Nuclear Energy (DOE-NE) programs, such as the Fuel Cycle Research and Development (FCRD), Advanced Reactor Concepts (ARC), Light Water… (more)

▼ Several Department of Energy Office of Nuclear Energy (DOE-NE) programs, such as the Fuel Cycle Research and Development (FCRD), Advanced Reactor Concepts (ARC), Light Water Reactor Sustainability, and Next Generation Nuclear Power Plants (NGNP), are investigating new fuels, materials, and inspection paradigms for advanced and existing reactors. A key objective of such programs is to understand the performance of these fuels and materials during irradiation. In DOE-NE’s FCRD program, ultrasonic based technology was identified as a key approach that should be pursued to obtain the high-fidelity, high-accuracy data required to characterize the behavior and performance of new candidate fuels and structural materials during irradiation testing. The radiation, high temperatures, and pressure can limit the available tools and characterization methods. In this thesis, two ultrasonic characterization techniques will be explored. The first, finite amplitude wave propagation has been demonstrated to be sensitive to microstructural material property changes. It is a strong candidate to determine fuel evolution; however, it has not been demonstrated for in-situ reactor applications. In this thesis, finite amplitude wave propagation will be used to measure the microstructural evolution in Al-6061. This is the first demonstration of finite amplitude wave propagation at temperatures in excess of 200 °C and during an irradiation test. Second, a method based on contact nonlinear acoustic theory will be developed to identify compressed cracks. Compressed cracks are typically transparent to ultrasonic wave propagation; however, by measuring harmonic content developed during finite amplitude wave propagation, it is shown that even compressed cracks can be characterized. Lastly, piezoelectric transducers capable of making these measurements are developed. Specifically, three piezoelectric sensors (Bismuth Titanate, Aluminum Nitride, and Zinc Oxide) are tested in the Massachusetts Institute of Technology Research reactor to a fast neutron fluence of 8.65x1020 n/cm2. It is demonstrated that Bismuth Titanate is capable of transduction up to 5 x1020 n/cm2, Zinc Oxide is capable of transduction up to 6.27 x1020 n/cm2, and Aluminum Nitride is capable of transduction up to 8.65x x1020 n/cm2. Advisors/Committee Members: Bernhard R Tittmann, Dissertation Advisor/Co-Advisor, Clifford Jesse Lissenden Iii, Committee Member, Albert Eliot Segall, Committee Member, Victor Ward Sparrow, Special Member.

Subjects/Keywords: Nonlinear Ultrasound; Contact Acoustic Nonlinear; Transducers; Neutron

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APA (6^th Edition):

Reinhardt, B. T. (2016). Nonlinear ultrasonic measurements in nuclear reactor environments. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/28985

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Reinhardt, Brian T. “Nonlinear ultrasonic measurements in nuclear reactor environments.” 2016. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/28985.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Reinhardt, Brian T. “Nonlinear ultrasonic measurements in nuclear reactor environments.” 2016. Web. 22 Jan 2021.

Vancouver:

Reinhardt BT. Nonlinear ultrasonic measurements in nuclear reactor environments. [Internet] [Thesis]. Penn State University; 2016. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/28985.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Reinhardt BT. Nonlinear ultrasonic measurements in nuclear reactor environments. [Thesis]. Penn State University; 2016. Available from: https://submit-etda.libraries.psu.edu/catalog/28985

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

4. Borawski, Brian. Multilayer Erosion Resistant Coatings for the Protection of Aerospace Components .

Degree: 2011, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/12384

► Application of a monolithic layer of titanium nitride (TiN) has been found to increase the erosion resistance of engine compressor components such as turbine blades.… (more)

▼ Application of a monolithic layer of titanium nitride (TiN) has been found to increase the erosion resistance of engine compressor components such as turbine blades. However, there is very limited public domain research on the erosion resistance conveyed by multilayer hard coatings. In addition, data from multilayer coating studies may present seemingly contradictory results due to the wide variation in coating systems and coating architectures investigated. This thesis presents a systematic study of multilayer coatings based on TiN/Ti and TiN/X, where X = Zr, Hf, or Nb, in order to determine the effect of multilayer coating design and interlayer materials on the hard particle erosion resistance of these coating systems. Multilayer coatings were eroded using glass beads, quartz and alumina media, with particle velocities ranging from 75 to 180 m/s. Erosion performance was found to depend strongly on the TiN/Ti coating multilayer design architecture and the erosion conditions. Coatings with two layers, one of TiN, the other a thin titanium bond layer, gave optimal erosion performance against the alumina erodent, whereas coatings with 32 layers (16 each of TiN and Ti) with a high volume fraction of titanium, offered the best erosion performance against the glass bead erodent. TiN-based coatings with interlayers of Ti, Zr, Hf, and Nb were compared to determine the effect of interlayer material on erosion performance. High values of Vickers microhardness were found to correlate with poor erosion performance. The TiN/Zr multilayer coatings exhibited the worst durability for all erosion conditions, followed by TiN/Hf. The TiN/Nb multilayer coatings provided the best durability for quartz and glass bead erodents. Although TiN/Ti coatings showed better durability than TiN/Nb against alumina particles, this discrepancy was attributed to the thinner than anticipated total thickness of the TiN/Nb coatings. Advisors/Committee Members: Judith Todd, Committee Chair/Co-Chair, Douglas Edward Wolfe, Committee Chair/Co-Chair, Jogender Singh, Committee Member, Albert Eliot Segall, Committee Member.

Subjects/Keywords: impact; coating; thin film; fracture; mechanics; ceramics; erosion; physical vapor deposition; titanium nitride

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APA (6^th Edition):

Borawski, B. (2011). Multilayer Erosion Resistant Coatings for the Protection of Aerospace Components . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/12384

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Borawski, Brian. “Multilayer Erosion Resistant Coatings for the Protection of Aerospace Components .” 2011. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/12384.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Borawski, Brian. “Multilayer Erosion Resistant Coatings for the Protection of Aerospace Components .” 2011. Web. 22 Jan 2021.

Vancouver:

Borawski B. Multilayer Erosion Resistant Coatings for the Protection of Aerospace Components . [Internet] [Thesis]. Penn State University; 2011. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/12384.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Borawski B. Multilayer Erosion Resistant Coatings for the Protection of Aerospace Components . [Thesis]. Penn State University; 2011. Available from: https://submit-etda.libraries.psu.edu/catalog/12384

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

5. Last, Beth Anna. Multi-scale Microstructure and Thermo-mechanical Characterization for Shape Memory Alloy Design via Additive Manufacturing.

Degree: 2019, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/15132bab5313

► The layer-by-layer deposition process of additive manufacturing (AM) offers the capability to design material microstructures on multiple length scales. For NiTi shape memory alloys, designing… (more)

▼ The layer-by-layer deposition process of additive manufacturing (AM) offers the capability to design material microstructures on multiple length scales. For NiTi shape memory alloys, designing material microstructures using AM would allow for unparalleled tailoring of the multiscale martensitic transformation and shape memory response. However, the laser-based directed energy deposition (LDED) AM technique produces localized microstructures which are distinct from those found in conventionally processed alloys. This work characterizes the grain and precipitate microstructures on multiple length scales for LDED fabricated NiTi alloys and assess the capability for tailoring the martensitic transformation morphology shape memory response through post-deposition heat treatments. Build coupons were fabricated by LDED AM using elementally blended Ni and Ti powder feedstock. The use of elemental powders allowed for a Ti-rich and a Ni-rich powder feedstock composition to be blended; thus, both shape memory effect (Ti-rich) and superelastic (Ni-rich) behaviors were investigated. Specimens were extracted from the fabricated build coupons to investigate the localized microstructure and shape memory behaviors. A full-field deformation analysis technique was employed to correlate the AM microstructure to the deformation mechanisms. The results of this work show that the NiTi LDED AM builds are inherently spatially varying on multiple microstructure length scales. The grain structure resulting from the AM process was similar for both feedstock compositions: fine grains within the interfacial regions formed by overlapping passes/layers and larger columnar grains within bulk regions (i.e. away from these interfaces). As a result of the spatially varying microstructure, as built LDED NiTi alloys exhibit a hardening like response and localized strain concentrations. Post-deposition heat treatment of the Ni-rich alloys reduced the spatial variation in the Ni4Ti3 precipitate microstructure and increased the localized superelastic strains compared to the as built condition, with the solutionizing and precipitation aging treatment resulting in the most spatially uniform Ni4Ti3 precipitate morphology. For the LDED alloys, shape memory effect recovery strains of 4.0 % (for Ti-rich alloys) and superelastic recovery strains of -6.0 % (for solutionized and aged Ni-rich alloys) were achieved. Advisors/Committee Members: Reginald Felix Hamilton, Dissertation Advisor/Co-Advisor, Reginald Felix Hamilton, Committee Chair/Co-Chair, Todd Palmer, Committee Member, Clifford Jesse Lissenden III, Committee Member, Allison Michelle Beese, Outside Member, Albert Eliot Segall, Committee Member.

Subjects/Keywords: shape memory alloy; additive manufacturing; microstructure; digital image correlation

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APA (6^th Edition):

Last, B. A. (2019). Multi-scale Microstructure and Thermo-mechanical Characterization for Shape Memory Alloy Design via Additive Manufacturing. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/15132bab5313

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Last, Beth Anna. “Multi-scale Microstructure and Thermo-mechanical Characterization for Shape Memory Alloy Design via Additive Manufacturing.” 2019. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/15132bab5313.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Last, Beth Anna. “Multi-scale Microstructure and Thermo-mechanical Characterization for Shape Memory Alloy Design via Additive Manufacturing.” 2019. Web. 22 Jan 2021.

Vancouver:

Last BA. Multi-scale Microstructure and Thermo-mechanical Characterization for Shape Memory Alloy Design via Additive Manufacturing. [Internet] [Thesis]. Penn State University; 2019. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/15132bab5313.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Last BA. Multi-scale Microstructure and Thermo-mechanical Characterization for Shape Memory Alloy Design via Additive Manufacturing. [Thesis]. Penn State University; 2019. Available from: https://submit-etda.libraries.psu.edu/catalog/15132bab5313

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

6. Nassar, Abdalla Ramadan. Investigation of laser-sustained plasma and the role of plasma in carbon dioxide laser nitriding of titanium.

Degree: 2012, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/16162

► Applications of plasma discharges to materials processing can be seen in everything from circuit boards to drill bits. However, plasma formed near the focus of… (more)

▼ Applications of plasma discharges to materials processing can be seen in everything from circuit boards to drill bits. However, plasma formed near the focus of a continuous laser beam, laser-sustained plasma (LSP), has hardly been considered for materials processing applications. This despite several remarkable properties: very high maximum electron temperatures (~17,000 K); high electron densities (on the order of 10²³ m^-3); and, the ability to be remotely moved simply by moving the focal point of the laser beam. In this work, several aspects of LSP were investigated. The electron temperature and electron density within an argon LSP were measured. These measurements were compared to the predictions of a computational fluid dynamics model, taking into account, for the first time, the effects of different laser beam modes. A nitrogen LSP was employed to gain new insights into the role of near-surface plasma in laser nitriding of titanium, a process in which nitrogen is introduced into a melted region formed by a scanning laser beam to produce a functionally-graded, hardened layer. Employing these insights, the production of large-area, crack-free, deep and oxygen-free laser-nitrided layers was demonstrated. The plasma temperature was measured via the relative intensities of excited atomic emission lines. This method, also known as a Boltzmann plot technique, relied on the assumption of local-thermodynamic equilibrium. The validity of this assumption was verified by measuring the spatially-resolved electron density using Stark broadening of the hydrogen-alpha emission line. However, reabsorption of plasma line emissions made temperature measurements using relative line intensities near the laser focus unreliable. That is, the region near the laser focus was found to be optically thick. An axi-symmetric model of a LSP sustained in a flow of argon was also developed under the assumption of local-thermodynamic equilibrium. The electron temperature and total beam absorption predicted by the model compared well with values from the literature and with the experimental results obtained using optical emission spectroscopy. The effect of several realistic laser beam modes were tested in the model using a "light pipe" technique. The validity of the technique was verified experimentally. A major part of this work was the application of LSP to investigate laser nitriding of titnaium. Interactions of the LSP with a surface were distinguished from interactions of the laser beam with a surface under conditions where the laser beam did not result in plasma formation. By combining this approach with optical emission spectroscopy, it was possible to decouple the effect of plasma and the laser beam during nitriding of titanium. In this way, new light was shed on the role of near-surface plasma during CO2 laser nitriding of titanium. Additionally, a new processing regime for near-stoichiometric, oxygen-free LSP nitriding of titanium was discovered. The work presented here culminates by demonstrating large-area, crack-free and… Advisors/Committee Members: Judith Todd Copley, Dissertation Advisor/Co-Advisor, Judith Todd Copley, Committee Chair/Co-Chair, Stephen M Copley, Special Member, John David Mathews, Committee Member, Albert Eliot Segall, Committee Member, Vladimir V Semak, Committee Member.

Subjects/Keywords: Laser-Sustained Plasma; LSP; Optical Discharge; Plasma; Nitriding; Laser Processing; Laser nitriding; Spectroscopy; CFD

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APA (6^th Edition):

Nassar, A. R. (2012). Investigation of laser-sustained plasma and the role of plasma in carbon dioxide laser nitriding of titanium. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/16162

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Nassar, Abdalla Ramadan. “Investigation of laser-sustained plasma and the role of plasma in carbon dioxide laser nitriding of titanium.” 2012. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/16162.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Nassar, Abdalla Ramadan. “Investigation of laser-sustained plasma and the role of plasma in carbon dioxide laser nitriding of titanium.” 2012. Web. 22 Jan 2021.

Vancouver:

Nassar AR. Investigation of laser-sustained plasma and the role of plasma in carbon dioxide laser nitriding of titanium. [Internet] [Thesis]. Penn State University; 2012. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/16162.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Nassar AR. Investigation of laser-sustained plasma and the role of plasma in carbon dioxide laser nitriding of titanium. [Thesis]. Penn State University; 2012. Available from: https://submit-etda.libraries.psu.edu/catalog/16162

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

7. Tremper, Amber Leigh. Effects of Nanoscale Coatings on Reliability of MEMS Ohmic Contact Switches.

Degree: 2013, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/17675

► This thesis examines how the electrical and mechanical behavior of Au thin films is altered by the presence of ultra-thin metallic coatings. To examine the… (more)

▼ This thesis examines how the electrical and mechanical behavior of Au thin films is altered by the presence of ultra-thin metallic coatings. To examine the mechanical behavior, nanoindentation, nano-scratch, and atomic force microscopy (AFM) testing was performed. The electrical behavior was evaluated through Kelvin probe contact resistance measurements. This thesis shows that ultra-thin, hard, ductile coatings on a softer, ductile underlying layer (such as Ru or Pt on Au) had a significant effect on mechanical behavior of the system, and can be tailored to control the deformation resistance of the thin film system. Despite Ru and Pt having a higher hardness and plane strain modulus than Au, the Ru and Pt coatings decreased both the hardness and plane strain modulus of the layered system when the indentation depth was on the order of the coating thickness. Alternately, when the indentation depth was several times the coating thickness, the ductile, plastically hard, elastically stiff layer significantly hardened the contact response. These results correlate well with membrane stress theoretical predictions, and demonstrate that membrane theory can be applied even when the ratio of indentation depth, h, to coating thickness, t, is very large (h/t<10). The transition from film-substrate models to membrane models occurs when the indent penetration depth to coating thickness ratio is less than ~0.5. When the electrical behavior of the Ru-coated Au films was examined, it was found that all the measured resistances of the Au-only film and Ru-coated systems were several orders of magnitude larger than those predicted by Holm’s law, but were still in good iii iv agreement with previously reported values in the literature. Previous studies attributed the high contact resistances to a variety of causes, including the buildup of an insulating contamination layer. This thesis determined the cause of the deviations to be large sheet resistance contributions to the total measured resistance. Further, studies on aged samples (with thicker contamination layers) conclusively showed that, while contamination increases the contact resistance, it also increases the dependence on force. This thesis also details that the relative contribution of contact resistance to the total measured resistance can be maximized by decreasing the probe spacing and tip radius. AFM testing of the layered systems showed that the coated samples had larger predicted plane strain moduli than the Au sample, in contrast to the nanoindentation testing. Thus, when the contact depth was kept sufficiently small, the contact stiffness increased as predicted by substrate models. When the contact depth was on the order of the coating thickness, the contact stiffness actually decreased. Additionally, the force- separation plots showed that the Ru and Pt surfaces either accumulated large amounts of contamination or were less susceptible to being wiped clean than the Au film. Further, scratch testing of the Au film and Ru and Pt coatings show that the hard surface… Advisors/Committee Members: Suzanne E Mohney, Dissertation Advisor/Co-Advisor, Dr Christopher Muhlstein, Dissertation Advisor/Co-Advisor, Paul Raymond Howell, Committee Member, Seong Han Kim, Committee Member, Albert Eliot Segall, Committee Member.

Subjects/Keywords: MEMS; ohmic; thin films; nanoindentation; coatings; ruthenium; gold; platinum; contact resistance

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APA (6^th Edition):

Tremper, A. L. (2013). Effects of Nanoscale Coatings on Reliability of MEMS Ohmic Contact Switches. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/17675

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Tremper, Amber Leigh. “Effects of Nanoscale Coatings on Reliability of MEMS Ohmic Contact Switches.” 2013. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/17675.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Tremper, Amber Leigh. “Effects of Nanoscale Coatings on Reliability of MEMS Ohmic Contact Switches.” 2013. Web. 22 Jan 2021.

Vancouver:

Tremper AL. Effects of Nanoscale Coatings on Reliability of MEMS Ohmic Contact Switches. [Internet] [Thesis]. Penn State University; 2013. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/17675.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Tremper AL. Effects of Nanoscale Coatings on Reliability of MEMS Ohmic Contact Switches. [Thesis]. Penn State University; 2013. Available from: https://submit-etda.libraries.psu.edu/catalog/17675

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

8. Ross, Jacob Wayne. On the Optimization of Composite Flywheel Rotors.

Degree: 2013, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/18997

► Energy storing flywheel rotor technology has yet to be fully optimized given the design possibilities. There have been many design approaches that have been published… (more)

▼ Energy storing flywheel rotor technology has yet to be fully optimized given the design possibilities. There have been many design approaches that have been published over the years, but no overall comparisons of the many manufacturable design options have been put forth. This research increases understanding of how boundary constraints coupled with optimization objective selection can affect optimized designs. This research also compares different design options by searching for the global optimum for all cases investigated: (A) varying the fiber/matrix ratio of each material ring in the composite rotor; (B) including radial fibers in addition to the circumferential fibers for each material ring; (C) co-mingling two fiber materials with a variable ratio in each material ring; (D) material ring press-fitting; and (E) matrix ballasting, where high-density particles can infiltrate the matrix to vary the density, stiffness, and thermal coefficient of expansion within each material ring. The results show that fixing both the outer and inner rotor radii in an optimization search produces a highly restrictive design constraint compared to when at least one of the radii are allowed to vary. The combinations that hold the most promise without producing overly restrictive, trivial, or degenerate solutions are as follows: (1) total stored energy, fixed outer radius, (2) specific energy, fixed outer radius, with a minimum total stored energy constraint. Concerning the design options, (B) has been shown to be a very poor design choice and should not be used. Option (D) has shown to have great potential in maximizing both total stored energy and specific energy, being the single best design option investigated. However, if the inner radius is allowed to vary, the total stored energy can be comparably maximized by combining options (C) and (E). Option (E) was found to be the second best design option with consistent reliability in improving performance. Advisors/Committee Members: Charles E Bakis, Dissertation Advisor/Co-Advisor, Charles E Bakis, Committee Chair/Co-Chair, Renata S Engel, Committee Member, George A Lesieutre, Committee Member, Albert Eliot Segall, Committee Member.

Subjects/Keywords: composite flywheel rotor; CMA-ES; evolutionary optimization; energy storage; press fit; matrix ballast; fiber comingling

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APA (6^th Edition):

Ross, J. W. (2013). On the Optimization of Composite Flywheel Rotors. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/18997

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Ross, Jacob Wayne. “On the Optimization of Composite Flywheel Rotors.” 2013. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/18997.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Ross, Jacob Wayne. “On the Optimization of Composite Flywheel Rotors.” 2013. Web. 22 Jan 2021.

Vancouver:

Ross JW. On the Optimization of Composite Flywheel Rotors. [Internet] [Thesis]. Penn State University; 2013. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/18997.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Ross JW. On the Optimization of Composite Flywheel Rotors. [Thesis]. Penn State University; 2013. Available from: https://submit-etda.libraries.psu.edu/catalog/18997

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

9. Sedigh-sarvestani, Madineh. Statistical and computational methods to investigate the relationship between sleep and seizure networks in the rodent brain.

Degree: 2013, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/18946

► Epilepsy is a neurological disorder characterized by the repeated occurrence of seizures. The unpredictable occurrence of seizures jeopardizes the quality of life of people with… (more)

▼ Epilepsy is a neurological disorder characterized by the repeated occurrence of seizures. The unpredictable occurrence of seizures jeopardizes the quality of life of people with drug-refractory epilepsy. Temporal lobe epilepsy (TLE) is the most common type of drug-resistant epilepsy in humans. Animal models of TLE provide a controlled system to investigate neural activity patterns that may be used to develop seizure prediction algorithms. Existing algorithms do not perform at a clinically meaningful level, in part because they do not incorporate known mechanisms of seizure susceptibility. State of vigilance (SOV) is one of the best established modulators of seizure susceptibility but is not commonly used in seizure prediction. We use the tetanus toxin (TeTX) model of TLE to investigate the relationship between SOV and seizure onset in rats. Our results indicate that rapid-eye-movement sleep (REM) is highly correlated with seizure onset in the TeTX model, an observation that directly challenges prevailing hypotheses regarding the relationship between SOV and seizures in TLE. Our results also indicate that unique mechanisms lead to transitions from REM to pathological and non-pathological states. To fully understand these mechanisms, novel observations related to sleep-wake regulatory system are necessary. Although mathematical models of its dynamics have been developed, the activity of this system is difficult to observe directly. Therefore we have developed a data assimilation framework that combines sparse measurements of the sleep-wake regulatory system together with a mathematical model of its dynamics to estimate the unmeasured variables. This toolset will allow us to understand the interaction between modulators of SOV and seizure susceptibility and may provide meaningful indicators of an impending seizure. Advisors/Committee Members: Bruce Gluckman, Dissertation Advisor/Co-Advisor, Steven Schiff, Committee Member, Corina Stefania Drapaca, Committee Member, Bernhard Luscher, Committee Member, Albert Eliot Segall, Committee Member, Steven Weinstein, Special Member.

Subjects/Keywords: Seizure prediction Sleep and Seizure Preseizure SOV Preseizure R

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APA (6^th Edition):

Sedigh-sarvestani, M. (2013). Statistical and computational methods to investigate the relationship between sleep and seizure networks in the rodent brain. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/18946

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Sedigh-sarvestani, Madineh. “Statistical and computational methods to investigate the relationship between sleep and seizure networks in the rodent brain.” 2013. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/18946.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Sedigh-sarvestani, Madineh. “Statistical and computational methods to investigate the relationship between sleep and seizure networks in the rodent brain.” 2013. Web. 22 Jan 2021.

Vancouver:

Sedigh-sarvestani M. Statistical and computational methods to investigate the relationship between sleep and seizure networks in the rodent brain. [Internet] [Thesis]. Penn State University; 2013. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/18946.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Sedigh-sarvestani M. Statistical and computational methods to investigate the relationship between sleep and seizure networks in the rodent brain. [Thesis]. Penn State University; 2013. Available from: https://submit-etda.libraries.psu.edu/catalog/18946

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

10. Kamat, Amar. A two-step CO₂ laser-sustained plasma nitriding process for deep-case hardening of commercially pure titanium.

Degree: 2016, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/13576amk410

► Titanium and its alloys possess several attractive properties that include a high strength-to-weight ratio, biocompatibility, and good corrosion resistance. However, due to their poor wear… (more)

▼ Titanium and its alloys possess several attractive properties that include a high strength-to-weight ratio, biocompatibility, and good corrosion resistance. However, due to their poor wear resistance, titanium components need to undergo surface hardening treatments before being used in applications involving high contact stresses. Laser nitriding is a thermochemical method of enhancing the surface hardness and wear resistance of titanium. This technique entails scanning the titanium substrate under a laser beam near its focal plane in the presence of nitrogen gas flow. At processing conditions characterized by low scan speeds, high laser powers, and small off-focal distances, a nitrogen plasma can be struck near the surface of the titanium substrate. When the substrate is removed, this plasma can be sustained indefinitely, away from any potentially interacting surfaces, by the laser beam power and a cascade ionization process. This dissertation explores the unique effects of nitriding titanium in the presence of such a laser-sustained plasma (LSP) in a processing chamber open to the atmosphere, with the ultimate objective of forming wide-area, deep, crack-free, wear-resistant nitrided cases on commercially pure titanium substrates. First, nitriding experiments were conducted at three processing conditions with and without a prestruck LSP. From optical and scanning electron microscopy, weight measurements, and temperature measurements, it was found that LSP nitriding increased nitrogen intake into the titanium melt pool, reduced surface oxidation, and broadened the energy distribution without causing energy attenuation when compared to conventional laser nitriding; these effects were most pronounced at the highest scan speed and lowest off-focal distance. Next, the effect of processing conditions on surface and cross-sectional microstructures during LSP nitriding was systematically evaluated by studying twenty experimental cases at varying off-focal distances, scan speeds, and gas flow compositions (nitrogen diluted by varying amounts of argon). X-ray diffraction conducted on the top surface of the nitrided trails confirmed the presence of TiN and TiN_0.3 phases. Although nitrogen dilution by argon was found to be necessary to prevent crack formation, microstructural characterization and weight measurements revealed that argon addition limited nitrogen intake into the melt pool by reducing Marangoni convection in the melt pool. Elimination of surface cracks thus came at the expense of reduced nitrogen content, shallower melt depths, and a reduced control over the microstructure of the resulting nitrided layer. To overcome these problems, a two-step process was proposed and developed. In the first step, a prestruck nitrogen LSP was used to deposit a single nitrided trail on the substrate; in the second step, a prestruck argon plasma was used to remelt the nitrided trail laid in step one. The nitriding and remelting steps were modeled using an analytical heat conduction solution valid for a moving heat… Advisors/Committee Members: Judith Todd Copley, Dissertation Advisor/Co-Advisor, Judith Todd Copley, Committee Chair/Co-Chair, Stephen M Copley, Committee Member, Albert Eliot Segall, Committee Member, Fan-Bill B Cheung, Outside Member, Adrianus C Van Duin, Outside Member.

Subjects/Keywords: titanium; laser-sustained plasma; laser nitriding; case hardening; wear resistance; laser materials processing

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APA (6^th Edition):

Kamat, A. (2016). A two-step CO₂ laser-sustained plasma nitriding process for deep-case hardening of commercially pure titanium. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/13576amk410

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kamat, Amar. “A two-step CO₂ laser-sustained plasma nitriding process for deep-case hardening of commercially pure titanium.” 2016. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/13576amk410.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kamat, Amar. “A two-step CO₂ laser-sustained plasma nitriding process for deep-case hardening of commercially pure titanium.” 2016. Web. 22 Jan 2021.

Vancouver:

Kamat A. A two-step CO₂ laser-sustained plasma nitriding process for deep-case hardening of commercially pure titanium. [Internet] [Thesis]. Penn State University; 2016. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/13576amk410.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kamat A. A two-step CO₂ laser-sustained plasma nitriding process for deep-case hardening of commercially pure titanium. [Thesis]. Penn State University; 2016. Available from: https://submit-etda.libraries.psu.edu/catalog/13576amk410

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

11. Parks, David Austin. Development of a Piezoelectric Ultrasonic Array Sensor for Nuclear Reactor Applications.

Degree: 2012, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/14020

► The recent Fukushima disaster has again demonstrated the need for improvements in nuclear power technology. The Fukushima disaster was essentially unstoppable once initiated, however the… (more)

Subjects/Keywords: ultrasonic; nuclear; piezoelectric; radiation damage

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APA (6^th Edition):

Parks, D. A. (2012). Development of a Piezoelectric Ultrasonic Array Sensor for Nuclear Reactor Applications. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/14020

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Parks, David Austin. “Development of a Piezoelectric Ultrasonic Array Sensor for Nuclear Reactor Applications.” 2012. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/14020.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Parks, David Austin. “Development of a Piezoelectric Ultrasonic Array Sensor for Nuclear Reactor Applications.” 2012. Web. 22 Jan 2021.

Vancouver:

Parks DA. Development of a Piezoelectric Ultrasonic Array Sensor for Nuclear Reactor Applications. [Internet] [Thesis]. Penn State University; 2012. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/14020.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Parks DA. Development of a Piezoelectric Ultrasonic Array Sensor for Nuclear Reactor Applications. [Thesis]. Penn State University; 2012. Available from: https://submit-etda.libraries.psu.edu/catalog/14020

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

12. Barthel, Anthony James. Vapor Adsorption And Reaction At Interfaces During tribological Sliding.

Degree: 2015, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/26396

► Friction and wear are not intrinsic material properties but instead depend on many extrinsic parameters of the sliding system. One important consideration when dealing with… (more)

▼ Friction and wear are not intrinsic material properties but instead depend on many extrinsic parameters of the sliding system. One important consideration when dealing with sliding surfaces is the vapor environment in which the two surfaces operate. Molecules from the vapor phase will adsorb onto the material surface, and even though these adsorbate layers are often less than one nanometer thick, they can influence friction and wear from the nano-scale to the macro-scale. This study investigates the effect of different adsorbed vapor molecules on the friction and wear during sliding between different solid surfaces. A macro-scale reciprocating ball-on flat tribometer was used to examine the effect of water vapor and various organic vapors on lubrication and wear primarily between steel or copper surfaces, but also with ceramic, glass, and carbon surfaces. With the exception of engineered materials like diamond-like carbon (DLC), all tested materials experience poor lubrication and surface wear when rubbed in a dry, inert environment. In the presence of water vapor, a copper surface rubbed by a stainless steel ball undergoes three distinct lubrication and wear conditions depending on the surrounding relative humidity (RH). Dry conditions and low humidity (<20% RH) produces plastic deformation and mild abrasive wear of the copper, intermediate humidity (20-80% RH) produces catastrophic adhesive wear of the copper, and high humidity (>80% RH) produces galvanic corrosion of the stainless steel ball. Other classes of materials generally do not show the same complicated RH dependence although RH does not act as a lubricant for most materials. In contrast to the complicated and deleterious effects of water vapor, organic vapors act as a lubricant across nearly all solid surfaces. Organic molecules including linear alcohols, branched alcohols, fluorinated alcohols, alkanes, and ketones provided lubrication. A monolayer of n-pentanol vapor yields a friction coefficient of ~0.15 and minimal wear regardless of the friction or wear that a surface experiences in dry or humid conditions. This lubrication occurs without any tribochemical reaction occurring. However, this lubrication is not observed with surfaces covered by residue from evaporated solvents. Low vapor pressure residue from trace contaminants in solvents gives a low friction coefficient and minimal wear for some surfaces. This study also investigates the effect of molecular structure of the adsorbate on friction and wear. Friction and wear decrease as hydrocarbon chain length increases for linear chain alcohols and branched alcohols have a higher friction coefficient than linear alcohols for the same number of carbons. Other molecular chemistries, including alkane, ketone, allyl alcohol, and fluorinated alcohol, had higher friction coefficients than n-pentanol. Unique to allyl alcohol is the formation of a large quantity… Advisors/Committee Members: Seong H Kim, Dissertation Advisor/Co-Advisor, Robert Martin Rioux Jr., Committee Member, Kyle Jeffrey Magnuson Bishop, Committee Member, Albert Eliot Segall, Committee Member.

Subjects/Keywords: tribology; surface science; mechanochemistry; vapor phase lubrication

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Barthel, A. J. (2015). Vapor Adsorption And Reaction At Interfaces During tribological Sliding. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/26396

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Barthel, Anthony James. “Vapor Adsorption And Reaction At Interfaces During tribological Sliding.” 2015. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/26396.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Barthel, Anthony James. “Vapor Adsorption And Reaction At Interfaces During tribological Sliding.” 2015. Web. 22 Jan 2021.

Vancouver:

Barthel AJ. Vapor Adsorption And Reaction At Interfaces During tribological Sliding. [Internet] [Thesis]. Penn State University; 2015. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/26396.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Barthel AJ. Vapor Adsorption And Reaction At Interfaces During tribological Sliding. [Thesis]. Penn State University; 2015. Available from: https://submit-etda.libraries.psu.edu/catalog/26396

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

13. Black, Amber N. An Exploration of Laser-sustained Plasma Interactions with Titanium Substrates During Nitriding Without Direct Irradiation by the Laser.

Degree: 2014, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/21421

► Laser-sustained plasma (LSP) is plasma which can be sustained indefinitely by a laser beam away from any potentially interacting surfaces. LSPs can be sustained at… (more)

▼ Laser-sustained plasma (LSP) is plasma which can be sustained indefinitely by a laser beam away from any potentially interacting surfaces. LSPs can be sustained at steady state by balancing power input through inverse bremsstrahlung absorption with loss through radiation (continuous and line), convection, and conduction. For many years, plasma has been considered a negative influence in laser materials processing, disrupting the beam path and distorting radiation prior to the beam reaching the surface. New research indicates that LSP can be an opportunity for metallurgical surface treatments and the deposition of coatings with an improvement in properties over conventional coating methods. For the first time, the LSP was used to nitride surfaces independently of the associated laser beam and the resulting specimens were examined to gain new insights into the effects of laser plasmas on surface modification processes. A titanium plate was placed parallel to and at a radial distance from an LSP, rather than perpendicular to it, as is the typical geometry for laser processing. During the exposure of the substrate to the LSP, the process was observed via a charge-coupled device (CCD) camera. The processed substrates were then examined visually, by scanning electron microscopy, energy dispersive x-ray spectroscopy, focused ion beam, transmission electron microscopy, and x-ray diffraction to elucidate the morphological and microstructural features that are characteristic of this processing method. Results indicated that an LSP is a powerful tool for heating surfaces and simultaneously introducing activated gas species into the melt. The nitrided surfaces exhibited complex and uncommon morphologies, including faceted titanium nitride crystals, which had not been produced by conventional laser nitriding. The underlying microstructure demonstrated that LSP can generate layers similar to those produced by conventional laser nitriding, but to a much greater depth. This characteristic structure exhibited four distinct layers with gradated nitrogen contents ranging from titanium nitride at the surface to the base titanium metal. A timeline for the evolution of these metallurgical transformations was developed based on process monitoring and the materials characterization. These observations also led to a new understanding of the influence of plasma on the laser nitriding process. New methods for observing LSP-material interactions without additional contributions from the laser beam itself were effectively employed. The viability of LSP nitriding as a surface modification process and as a tool for future research on plasma-substrate interactions is discussed. Advisors/Committee Members: Judith Todd Copley, Dissertation Advisor/Co-Advisor, Stephen M Copley, Committee Member, James Hansell Adair, Committee Member, Albert Eliot Segall, Committee Member, Dr Vladimir V Semak, Committee Member.

Subjects/Keywords: laser; plasma; nitriding; titanium; laser-sustained plasma; laser material processing; laser nitriding

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APA (6^th Edition):

Black, A. N. (2014). An Exploration of Laser-sustained Plasma Interactions with Titanium Substrates During Nitriding Without Direct Irradiation by the Laser. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/21421

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Black, Amber N. “An Exploration of Laser-sustained Plasma Interactions with Titanium Substrates During Nitriding Without Direct Irradiation by the Laser.” 2014. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/21421.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Black, Amber N. “An Exploration of Laser-sustained Plasma Interactions with Titanium Substrates During Nitriding Without Direct Irradiation by the Laser.” 2014. Web. 22 Jan 2021.

Vancouver:

Black AN. An Exploration of Laser-sustained Plasma Interactions with Titanium Substrates During Nitriding Without Direct Irradiation by the Laser. [Internet] [Thesis]. Penn State University; 2014. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/21421.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Black AN. An Exploration of Laser-sustained Plasma Interactions with Titanium Substrates During Nitriding Without Direct Irradiation by the Laser. [Thesis]. Penn State University; 2014. Available from: https://submit-etda.libraries.psu.edu/catalog/21421

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

14. Guers, Manton John. IN-SITU MONITORING OF REMOTE SPECIMENS USING ULTRASONIC GUIDED WAVES .

Degree: 2011, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/11445

► There are a wide variety of engineering applications where it can be advantageous to perform real time ultrasonic measurements. In structural health monitoring (SHM) applications… (more)

▼ There are a wide variety of engineering applications where it can be advantageous to perform real time ultrasonic measurements. In structural health monitoring (SHM) applications (aircraft, bridges, etc.), real time data can be used to improve safety and reduce maintenance costs. In other applications (such as carbon-carbon production and ceramic sintering) in-situ ultrasonic measurements can be used to study how a material is affected by different manufacturing conditions. Ultrasonic measurements can also be used in place of convention temperature, pressure, fluid flow, or level sensors. The work presented in this dissertation focused on studying an ultrasonic guided waves based system for performing in-situ measurements on specimens which are commonly used in the accelerated life tests conducted in materials and test reactors (MTRs). Using this system, ultrasonic waves could be sent down a thirty foot long waveguide to a specimen while locating the transducer outside of the hostile environment. Both the theoretical and experimental results demonstrated how individual components of the system influenced the monitoring capabilities. As one example, the in-situ monitoring system was studied for use in measuring the change in length of creep specimens. Successful measurements of creep elongation were demonstrated using a pulse-echo configuration of the in-situ monitoring system. In addition, the temperature dependence of the in-situ creep measurement was also studied. Both theoretical calculations and experiments showed that the temperature dependence of group velocity was approximately linear for the creep specimen geometry. ‘Blister’ specimens having a rectangular cross-section were also considered in this work. Theoretically driven semi-analytical finite element (SAFE) calculations, time-domain finite element calculations, and experimental measurements were performed to investigate guided wave propagation in this specimen. The SAFE calculations, finite element predictions, and experimental results all demonstrated good agreement. In general, the guided wave mode with the fastest group velocity appeared to be the most prominent in both the simulated and experimentally measured waveforms. Several types of defects were considered. Defects can sometimes produce temperature anomalies in the specimen. The models indicated that detection of a defect induced temperature gradient in the rectangular ‘blister’ specimen was possible. In the design and operation of an in-situ monitoring system based on guided ultrasonic waves, the transducer design plays an important roll in the performance of the system. In this work, a magnetostrictive sleeve design was tested as an alternative to a wire-wire joint configuration. Results showed that the sleeve design was effective for generating ultrasonic guided waves in the wire waveguide. In addition, the sleeve design simplifies specimen fabrication, minimizes the amount of magnetostrictive material required, and eliminates the artifacts associated with the… Advisors/Committee Members: Bernhard R Tittmann, Dissertation Advisor/Co-Advisor, Bernhard R Tittmann, Committee Chair/Co-Chair, Joseph Lawrence Rose, Committee Member, Clifford Jesse Lissenden Iii, Committee Member, Albert Eliot Segall, Committee Member, Karl Martin Reichard, Committee Member.

Subjects/Keywords: structural health monitoring; remote monitoring; ultrasonic guided wave

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APA (6^th Edition):

Guers, M. J. (2011). IN-SITU MONITORING OF REMOTE SPECIMENS USING ULTRASONIC GUIDED WAVES . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/11445

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Guers, Manton John. “IN-SITU MONITORING OF REMOTE SPECIMENS USING ULTRASONIC GUIDED WAVES .” 2011. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/11445.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Guers, Manton John. “IN-SITU MONITORING OF REMOTE SPECIMENS USING ULTRASONIC GUIDED WAVES .” 2011. Web. 22 Jan 2021.

Vancouver:

Guers MJ. IN-SITU MONITORING OF REMOTE SPECIMENS USING ULTRASONIC GUIDED WAVES . [Internet] [Thesis]. Penn State University; 2011. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/11445.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Guers MJ. IN-SITU MONITORING OF REMOTE SPECIMENS USING ULTRASONIC GUIDED WAVES . [Thesis]. Penn State University; 2011. Available from: https://submit-etda.libraries.psu.edu/catalog/11445

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

15. Muller, Andrea Marie. IDENTIFICATION OF FUNDAMENTAL DEFORMATION AND FAILURE MECHANISMS IN ARMOR CERAMICS.

Degree: 2011, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/12395

► Indentation of a surface with a hard sphere can be used to examine micromechanical response of a wide range of materials and has been shown… (more)

▼ Indentation of a surface with a hard sphere can be used to examine micromechanical response of a wide range of materials and has been shown to generate loading conditions resembling early stages of ballistic impact events. Cracking morphologies also show similarities, particularly with formation of cone cracks at the contact site. The approach in this thesis is to use this indentation technique to characterize contact damage and deformation processes in armor ceramics, as well as identify the role of cone cracking and inelastic behavior. To accomplish these objectives, an instrumented indentation system was designed and fabricated, extending depth-sensing capabilities originally developed for nano-indentation to higher forces. This system is also equipped with an acoustic emission system to detect onset of cone cracking and subsequent failure. Once calibrated and verified the system was used to evaluate elastic modulus and cone crack initiation forces of two commercial float glasses. As-received air and tin surfaces of soda-lime-silica and borosilicate float glass were tested to determine differences in elastic and fracture behavior. Information obtained from load–displacement curves and visual inspection of indentation sites were used to determine elastic modulus, and conditions for onset of cone cracking as a function of surface roughness. No difference in reduced modulus or cone cracking loads on as-received air and tin surfaces were observed. Abraded surfaces showed the tin surface to be slightly more resistant to cone cracking. A study focusing on the transition from elastic to inelastic deformation in two transparent fine-grained polycrystalline spinels with different grain sizes was then conducted. Congruent experiments included observations on evolution of damage, examinations of sub-surface damage and inspection of remnant surface profiles. Indentation stress–strain behavior obtained from load–displacement curves revealed a small difference in yielding and strain-hardening behavior given the significant grain size difference. Directly below the indentation sites, regions of grain boundary cracking, associated with the inelastic zone, were identified in both spinels. Comparison of Meyer hardness and in-situ hardness showed a discrepancy at low loads, a result of elastic recovery. Elastic-plastic indentation behavior of the two spinels was then compared to behavior of a transparent large-grained aluminum oxinitirde (AlON) and a small-grained sintered aluminum nitride (AlN). Subsurface indentation damage revealed transitions from intergranular to transgranular fracture in the two spinels, AlON showed a transition from multiple cleavage microcracks to transgranular fracture while AlN exhibited only intergranular fracture. Analysis of indentation stress-strain results showed a slight difference in yielding behaviors of the two spinels and AlON whereas AlN showed a much lower yield value comparatively. Slight differences in strain-hardening behavior were observed. When comparing indentation stress–strain energy… Advisors/Committee Members: David John Green, Dissertation Advisor/Co-Advisor, David John Green, Committee Chair/Co-Chair, John Richard Hellmann Jr., Committee Member, Christopher L Muhlstein, Committee Member, Albert Eliot Segall, Committee Member.

Subjects/Keywords: Spherical Indentation; Ceramic Armor; Spinel; AlON; AlN

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APA (6^th Edition):

Muller, A. M. (2011). IDENTIFICATION OF FUNDAMENTAL DEFORMATION AND FAILURE MECHANISMS IN ARMOR CERAMICS. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/12395

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Muller, Andrea Marie. “IDENTIFICATION OF FUNDAMENTAL DEFORMATION AND FAILURE MECHANISMS IN ARMOR CERAMICS.” 2011. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/12395.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Muller, Andrea Marie. “IDENTIFICATION OF FUNDAMENTAL DEFORMATION AND FAILURE MECHANISMS IN ARMOR CERAMICS.” 2011. Web. 22 Jan 2021.

Vancouver:

Muller AM. IDENTIFICATION OF FUNDAMENTAL DEFORMATION AND FAILURE MECHANISMS IN ARMOR CERAMICS. [Internet] [Thesis]. Penn State University; 2011. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/12395.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Muller AM. IDENTIFICATION OF FUNDAMENTAL DEFORMATION AND FAILURE MECHANISMS IN ARMOR CERAMICS. [Thesis]. Penn State University; 2011. Available from: https://submit-etda.libraries.psu.edu/catalog/12395

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

16. Likhanskii, Alexandre. STUDY OF PLASMA PHENOMENA AT HIGH ELECTRIC FIELDS IN APPLICATIONS FOR ACTIVE FLOW CONTROL AND ULTRA-SHORT PULSE LASER DRILLING .

Degree: 2009, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/10015

► Plasma engineering is one of the most actively growing research areas in modern science. Over the past decade, plasma engineering became a significant part of… (more)

▼ Plasma engineering is one of the most actively growing research areas in modern science. Over the past decade, plasma engineering became a significant part of aerospace engineering, material processing, medicine, geosciences, etc. One of the main goals of plasma research is to discover new perspectives in a wide range of research areas. It makes plasma engineering a truly interdisciplinary subject. Recently, a significant interest in the aerospace community was caused by the possibility of an active flow control using dielectric barrier discharge (DBD) plasma actuators. A number of groups tried to explain the physics of the experimentally observed phenomena. However, the developed models could hardly explain the DBD phenomena even qualitatively. This thesis presents the first complete, comprehensive, physically-based model, which tracks all essential physics of the DBD plasma actuators and utilizes modern numerical capabilities for efficient simulations. By using the developed model, the physics of the plasma actuators was explained. Based on the understanding of the operation of the conventional DBD, driven by a sinusoidal voltage, a novel configuration was proposed. The sinusoidal driving voltage was substituted by the repetitive nanosecond pulses superimposed on the bias voltage. The advantages of the proposed concept over the conventional one were experimentally validated. The developed model demonstrated flexibility for different plasma engineering areas. The model can be used not only for a description of the DBD plasma actuators, but also for a number of problems involving the gas discharges. By using the developed model, plasma generation by the ferroelectric plasma source, which is used in fusion technology, was explained. In the area of material processing, a significant interest was caused by an apparent possibility of precise high intensity ultra-short laser pulse drilling with negligible melt production. However, the experiments did not validate the theories proposed in literature. In order to explain the experimental data and analyze the possibility of reduction of melt generation, a new model for laser pulse drilling was developed in this thesis. The model comprehensively describes laser-material interaction and explains the significant amount of melt production in the case of ultra-short laser pulses. The results of the simulations are in good agreement with the experimental data. Advisors/Committee Members: Vladimir Semak, Dissertation Advisor/Co-Advisor, Vladimir Semak, Committee Chair/Co-Chair, Akhlesh Lakhtakia, Committee Chair/Co-Chair, Albert Eliot Segall, Committee Member, Victor P Asko, Committee Member.

Subjects/Keywords: flow control; gas discharge; Plasma physics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Likhanskii, A. (2009). STUDY OF PLASMA PHENOMENA AT HIGH ELECTRIC FIELDS IN APPLICATIONS FOR ACTIVE FLOW CONTROL AND ULTRA-SHORT PULSE LASER DRILLING . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/10015

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Likhanskii, Alexandre. “STUDY OF PLASMA PHENOMENA AT HIGH ELECTRIC FIELDS IN APPLICATIONS FOR ACTIVE FLOW CONTROL AND ULTRA-SHORT PULSE LASER DRILLING .” 2009. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/10015.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Likhanskii, Alexandre. “STUDY OF PLASMA PHENOMENA AT HIGH ELECTRIC FIELDS IN APPLICATIONS FOR ACTIVE FLOW CONTROL AND ULTRA-SHORT PULSE LASER DRILLING .” 2009. Web. 22 Jan 2021.

Vancouver:

Likhanskii A. STUDY OF PLASMA PHENOMENA AT HIGH ELECTRIC FIELDS IN APPLICATIONS FOR ACTIVE FLOW CONTROL AND ULTRA-SHORT PULSE LASER DRILLING . [Internet] [Thesis]. Penn State University; 2009. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/10015.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Likhanskii A. STUDY OF PLASMA PHENOMENA AT HIGH ELECTRIC FIELDS IN APPLICATIONS FOR ACTIVE FLOW CONTROL AND ULTRA-SHORT PULSE LASER DRILLING . [Thesis]. Penn State University; 2009. Available from: https://submit-etda.libraries.psu.edu/catalog/10015

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

17. Abrams, Matthew Benjamin. Crack Propagation and Fracture in Engineered Stress Profile Glass .

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/6285

► Ion exchange procedures have been developed for soda lime silicate and soda alumina silicate glasses that produce a maximum compressive stress below the surface of… (more)

Subjects/Keywords: ion exchange; r-curve; crack growth; fracture; glass

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APA (6^th Edition):

Abrams, M. B. (2008). Crack Propagation and Fracture in Engineered Stress Profile Glass . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/6285

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Abrams, Matthew Benjamin. “Crack Propagation and Fracture in Engineered Stress Profile Glass .” 2008. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/6285.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Abrams, Matthew Benjamin. “Crack Propagation and Fracture in Engineered Stress Profile Glass .” 2008. Web. 22 Jan 2021.

Vancouver:

Abrams MB. Crack Propagation and Fracture in Engineered Stress Profile Glass . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/6285.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Abrams MB. Crack Propagation and Fracture in Engineered Stress Profile Glass . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/6285

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

18. HERNANDEZ, ROSE MARIE. INTEGRATED CHEMICAL AND BIOLOGICAL SYSTEMS IN NANOWIRE STRUCTURES TOWARDS NANO-SCALE SENSORS .

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/6848

► Nanowires composed of metal and conducting polymers with integrated proteins and chemical systems have been investigated as building blocks for next-generation nano-scale sensors and assemblies.… (more)

Subjects/Keywords: Nanowires; nanosensors; conducting polymer nanowires

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APA (6^th Edition):

HERNANDEZ, R. M. (2008). INTEGRATED CHEMICAL AND BIOLOGICAL SYSTEMS IN NANOWIRE STRUCTURES TOWARDS NANO-SCALE SENSORS . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/6848

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

HERNANDEZ, ROSE MARIE. “INTEGRATED CHEMICAL AND BIOLOGICAL SYSTEMS IN NANOWIRE STRUCTURES TOWARDS NANO-SCALE SENSORS .” 2008. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/6848.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

HERNANDEZ, ROSE MARIE. “INTEGRATED CHEMICAL AND BIOLOGICAL SYSTEMS IN NANOWIRE STRUCTURES TOWARDS NANO-SCALE SENSORS .” 2008. Web. 22 Jan 2021.

Vancouver:

HERNANDEZ RM. INTEGRATED CHEMICAL AND BIOLOGICAL SYSTEMS IN NANOWIRE STRUCTURES TOWARDS NANO-SCALE SENSORS . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/6848.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

HERNANDEZ RM. INTEGRATED CHEMICAL AND BIOLOGICAL SYSTEMS IN NANOWIRE STRUCTURES TOWARDS NANO-SCALE SENSORS . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/6848

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

19. Luscher, Walter Gordon. Role of Composition and Oxygen Partial Pressure on Microstructural and Crystalline Phase Evolution in Aluminosilicate Derived Aggregates.

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/7671

► Spherical aggregates, approximately 1mm in diameter, derived from either kaolinite or bauxite are used in tonnage quantities to aid the extraction of oil and natural… (more)

Subjects/Keywords: Bauxite; Kaolinite; Diametral Compression; Petroleum Industry; Fossil Fuel Extraction

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APA (6^th Edition):

Luscher, W. G. (2008). Role of Composition and Oxygen Partial Pressure on Microstructural and Crystalline Phase Evolution in Aluminosilicate Derived Aggregates. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/7671

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Luscher, Walter Gordon. “Role of Composition and Oxygen Partial Pressure on Microstructural and Crystalline Phase Evolution in Aluminosilicate Derived Aggregates.” 2008. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/7671.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Luscher, Walter Gordon. “Role of Composition and Oxygen Partial Pressure on Microstructural and Crystalline Phase Evolution in Aluminosilicate Derived Aggregates.” 2008. Web. 22 Jan 2021.

Vancouver:

Luscher WG. Role of Composition and Oxygen Partial Pressure on Microstructural and Crystalline Phase Evolution in Aluminosilicate Derived Aggregates. [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/7671.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Luscher WG. Role of Composition and Oxygen Partial Pressure on Microstructural and Crystalline Phase Evolution in Aluminosilicate Derived Aggregates. [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/7671

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

20. Lee, Chong Myoung. Elastic Waves in Bounded Structures with an Arbitrary Cross-Section .

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/7023

► A train is one of the oldest and most important transportation methods for moving people and goods. A train accident can causes serious casualties and… (more)

▼ A train is one of the oldest and most important transportation methods for moving people and goods. A train accident can causes serious casualties and property damage. Many factors could lead to a train disaster and the defects in rail are one of the major problems. Detection of defects and proper maintenance action for a rail is therefore essential. There are two kinds of typical defects in a rail head. They are shelling and transverse defects. Shelling is a horizontal plane defect generated by the sliding and/or rolling the wheel over the rail from shear reversal and is usually located just below the top surface of the rail. The transverse defects are usually generated and grown inside the rail head from the shelling region down into the head. Shelling is not fatal but transverse defects are. Conventional ultrasonic tests (the normal incident technique and the oblique incident technique) have difficulties in detecting the transverse defects under the shelling, because most of the ultrasonic energy is reflected from the shelling. For this reason, the guided wave ultrasonic technique is potentially a suitable method for detecting defects under the shelling. The cross-sectional area of the shelling is much smaller than that of the transverse defects in the guided wave propagation direction. The purpose of this study is therefore to find an appropriate guided wave mode and frequency for the detection of a transverse defect under the shelling. The phase velocity and group velocity dispersion curves are calculated numerically using a semi-analytical finite element method (SAFE). From the phase velocity dispersion curves, the spacing of the elements in an electromagnetic acoustic transducer (EMAT), an important feature in EMAT design, is determined to generate the appropriate guided waves for reliable defect detection. Characteristics of the guided wave propagation is also explored at various points in the phase velocity dispersion curves using ABAQUS/Explicit, a commercially available finite element method (FEM) package with a simulation of a Lamb type EMAT. Finally, the aspect of the wave scattering of guided waves from several types of defects along with the shelling located in the rail head is examined. This research provides a new modeling technique to simulate the EMAT loading and can suggest guide lines for a new inspection technique for finding defects in the rail head under shelling using EMATs. Furthermore, the research area can be extended to a study of various types of defects, different location of the defects, different loading positions, various welding zones, and overall changes in rail boundary conditions. Advisors/Committee Members: Joseph Lawrence Rose, Committee Chair/Co-Chair, Bernhard R Tittmann, Committee Member, Eduard E Ventsel, Committee Member, Albert Eliot Segall, Committee Member, Sunil K Sinha, Committee Member.

Subjects/Keywords: ultrasonic; arbtrary corss section; guided wave; rail inspection

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Lee, C. M. (2008). Elastic Waves in Bounded Structures with an Arbitrary Cross-Section . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/7023

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Lee, Chong Myoung. “Elastic Waves in Bounded Structures with an Arbitrary Cross-Section .” 2008. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/7023.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Lee, Chong Myoung. “Elastic Waves in Bounded Structures with an Arbitrary Cross-Section .” 2008. Web. 22 Jan 2021.

Vancouver:

Lee CM. Elastic Waves in Bounded Structures with an Arbitrary Cross-Section . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/7023.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Lee CM. Elastic Waves in Bounded Structures with an Arbitrary Cross-Section . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/7023

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

21. Koseski, Ryan Paul. Manipulation of Microstructrue, Phase Evolution and Mechanical Properties by Devitrification of Andesite for use as Proppant .

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/9195

► Small, roughly spherical ceramic particles, approximately 1mm in size are used for a number of applications including casting sands, catalysts, and cement fillers. The oil… (more)

▼ Small, roughly spherical ceramic particles, approximately 1mm in size are used for a number of applications including casting sands, catalysts, and cement fillers. The oil and natural gas industry utilizes such materials in tonnage quantities yearly as extraction aids. Particles intended for this application are referred to as proppants. Proppants are composed of materials that differ by density, strength and cost, and are selected on a site by site basis. Recently, competing usage and depletion of reserves of one of the most popular category of proppant materials, sintered aluminosilicates (e.g. kaolinite, bauxite) have driven the need for alternative raw materials for proppant manufacturing. Andesite, a by-product of mining operations in the south-west United States was identified as an abundant, readily available, and low cost alternative proppant material that can be fused and net-shaped into a glass which when crystallized results in microstructures which may offer substantial toughening and fracture characteristics which may serve to their advantage for use as proppants that do not decrease the permeability (gblindh) the particle bed. This study addressed the devitrification behavior and its role on the mechanical properties of andesite-based glass-ceramic spheres for use as proppants. Time-temperature-transformation studies were performed to evaluate the devitrification behavior of andesite glass. Crystalline phase evolution and microstructural development were evaluated using quantitative x-ray diffraction, scanning electron microscopy, differential thermal analysis, and spectrophotometry. The andesite glass devitrification commenced with the precipitation of iron oxides (magnetite) which served as seeds for the epitaxial growth of dendritic pyroxenes. Mechanical properties, such as diametral compressive strength, fracture toughness, hardness, and fracture morphology were correlated with crystalline phase evolution. Selected heat treatments resulting in the desired combination of high strength, toughness, and coarse fragmentation of crystallized spheres were performed for subsequent evaluation of performance as a proppant using American Petroleum Institute test methodologies. For nominally 1mm diameter devitrified proppants, diametral compressive strengths of 150MPa were observed, while results of indentation fracture resistance measurements showed values of 1.5-2.0MPa∙ãm. Combinations of these mechanical properties resulted in nearly 80% incidence of coarse fragmentation compared with 40% incidence in amorphous andesite proppants. Results corroborated the hypothesis that controlled devitrification resulted in substantial improvement in toughness and fracture morphology which in turn contributed to enhanced permeability of packed particle beds relative to state of the art glass proppants, and comparable to the present state of the art sintered bauxite- and kaolinite-based proppants. Advisors/Committee Members: John Richard Hellmann Jr., Committee Chair/Co-Chair, David John Green, Committee Member, Barry Earl Scheetz, Committee Chair/Co-Chair, Carlo G Pantano, Committee Member, Albert Eliot Segall, Committee Member.

Subjects/Keywords: Glass-Ceramic; Proppant; Andesite; Hydrocarbon Recovery; Basalt

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Koseski, R. P. (2008). Manipulation of Microstructrue, Phase Evolution and Mechanical Properties by Devitrification of Andesite for use as Proppant . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/9195

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Koseski, Ryan Paul. “Manipulation of Microstructrue, Phase Evolution and Mechanical Properties by Devitrification of Andesite for use as Proppant .” 2008. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/9195.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Koseski, Ryan Paul. “Manipulation of Microstructrue, Phase Evolution and Mechanical Properties by Devitrification of Andesite for use as Proppant .” 2008. Web. 22 Jan 2021.

Vancouver:

Koseski RP. Manipulation of Microstructrue, Phase Evolution and Mechanical Properties by Devitrification of Andesite for use as Proppant . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/9195.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Koseski RP. Manipulation of Microstructrue, Phase Evolution and Mechanical Properties by Devitrification of Andesite for use as Proppant . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/9195

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

22. Pavlacka, Robert Joseph. Processing and Properties of Al2O3 Microstructure Composites.

Degree: 2009, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/9837

► We have proposed a new class of composites that accesses different component properties not through the use of distinct materials, but through the exploitation of… (more)

▼ We have proposed a new class of composites that accesses different component properties not through the use of distinct materials, but through the exploitation of the microstructure-property relationship within a single material. That is, we seek to adapt composite concepts to take advantage of the considerable variance in properties associated with different microstructures. This new class of composites is called microstructure composites. Microstructure composites are predominately single phase ceramics that utilize multiple distinct microstructure features in the same composite to obtain unique property combinations. Spatial control and composite connectivity of the individual microstructure components of a microstructure composite are ultimately the key to developing and controlling useful and unique properties. Microstructural features can be controlled via the starting location and transport of the dopants, minority second phases, and liquid phases that are used to manipulate microstructure development. This work focuses on textured-equiaxed microstructure in the Al2O3 system. Texture is obtained in situ using templated grain growth (TGG). To control microstructure development locally during microstructure composite fabrication, it is important to use relatively low levels of dopant to mitigate the effects of dopant interdiffusion. Therefore, the development of texture in α-Al2O3 using TGG was explored under low liquid-phase dopant concentration conditions. High temperature dilatometry was performed to quantify the effect of template constraint on x-y plane shirinkage and the extent to which this constraint could be mitigated as a function of the dopant concentration. x-y plane shrinkage was observed to be increasingly constrained with increasing template loadng and decreasing dopant concentration. Final x-y plane shrinkage was greater for samples with 0.14 wt% dopant than for those without dopant, despite have a much lower peak strain rate. It was concluded that densification was impeded by the dopant at lower temperatures but enhanced significantly above 1450°C. Texture is highly developed in samples with no dopant and 0.14 wt% dopant by 1550°C and in samples with 2 wt% dopant by 1350°C. We proposed a new class of composites (called microstructure composites) that accesses different component properties not through the use of distinct materials, but rather through the exploitation of the microstructure-property relationship within a single material. Microstructure composites, therefore, are single phase ceramics that combine components with distinct microstructures within a single composite to obtain unique property combinations. Spatial control and composite connectivity of the individual microstructural ‘components’ of a microstructure composite are ultimately the key to developing and controlling useful and unique properties. Microstructural components are developed by controlling the starting location and transport of dopants during processing and sintering. This work focuses on… Advisors/Committee Members: Gary Lynn Messing, Dissertation Advisor/Co-Advisor, Gary Lynn Messing, Committee Chair/Co-Chair, David John Green, Committee Member, John Richard Hellmann Jr., Committee Member, Albert Eliot Segall, Committee Member.

Subjects/Keywords: texture; templated grain growth; non-catastrophic failure; fracture; alumina; microstructure composite; composite

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APA (6^th Edition):

Pavlacka, R. J. (2009). Processing and Properties of Al2O3 Microstructure Composites. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/9837

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Pavlacka, Robert Joseph. “Processing and Properties of Al2O3 Microstructure Composites.” 2009. Thesis, Penn State University. Accessed January 22, 2021. https://submit-etda.libraries.psu.edu/catalog/9837.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Pavlacka, Robert Joseph. “Processing and Properties of Al2O3 Microstructure Composites.” 2009. Web. 22 Jan 2021.

Vancouver:

Pavlacka RJ. Processing and Properties of Al2O3 Microstructure Composites. [Internet] [Thesis]. Penn State University; 2009. [cited 2021 Jan 22]. Available from: https://submit-etda.libraries.psu.edu/catalog/9837.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Pavlacka RJ. Processing and Properties of Al2O3 Microstructure Composites. [Thesis]. Penn State University; 2009. Available from: https://submit-etda.libraries.psu.edu/catalog/9837

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Open Access Theses and Dissertations