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View-centric reasoning about parallel and distributed computation
Title
View-centric reasoning about parallel and distributed computation.
Creator
Smith, Marc L., Parsons, Rebecca J.; Hughes, Charles E., Engineering and Computer Science
Abstract / Description
University of Central Florida College of Engineering Thesis; The development of distributed applications has not progressed as rapidly as its enabling technologies. In part, this is due to the difficulty of reasoning about such complex systems. In contrast to sequential systems, parallel systems give rise to parallel events, and the resulting uncertainty of the observed order of these events. Loosely coupled distributed systems complicate this even further by introducing the element of...
Show moreUniversity of Central Florida College of Engineering Thesis; The development of distributed applications has not progressed as rapidly as its enabling technologies. In part, this is due to the difficulty of reasoning about such complex systems. In contrast to sequential systems, parallel systems give rise to parallel events, and the resulting uncertainty of the observed order of these events. Loosely coupled distributed systems complicate this even further by introducing the element of multiple imperfect observers of these parallel events. The goal of this dissertation is to advance parallel and distributed systems development by producing a parameterized model that can be instantiated to reflect the computation and coordination properties of such systems. The result is a model called paraDOS that we show to be general enough to have instantiations of two very distinct distributed computation models, Actors and tuple space. We show how paraDOS allows us to use operational semantics to reason about computation when such reasoning must account for multiple, inconsistent and imperfect views. We then extend the paraDOS model with an abstraction to support composition of communicating computational systems. This extension gives us a tool to reason formally about heterogeneous systems, and about new distributed computing paradigms such as the multiple tuple spaces support seen in Sun's JavaSpaces and IBM's T Spaces.
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Date Issued
2000
Identifier
CFR0000189, ucf:53138
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFR0000189
Characterization of SLM-Manufactured Turbine Blade Microfeatures from Superalloy Powders
Title
Characterization of SLM-Manufactured Turbine Blade Microfeatures from Superalloy Powders.
Creator
Ealy, Brandon, Kapat, Jayanta, Ahmed, Kareem, Vasu Sumathi, Subith, University of Central Florida
Abstract / Description
The limits of gas turbine technology are heavily influenced by materials and manufacturing capabilities. Inconel remains the material of choice for most hot gas path (HGP) components in gas turbines, however recent increases in turbine inlet temperature (TIT) are associated with the development of advanced convective cooling methods and ceramic thermal barrier coatings. Increasing cycle efficiency and cycle specific work are the primary drivers for increasing TIT. Lately, incremental...
Show moreThe limits of gas turbine technology are heavily influenced by materials and manufacturing capabilities. Inconel remains the material of choice for most hot gas path (HGP) components in gas turbines, however recent increases in turbine inlet temperature (TIT) are associated with the development of advanced convective cooling methods and ceramic thermal barrier coatings. Increasing cycle efficiency and cycle specific work are the primary drivers for increasing TIT. Lately, incremental performance gains responsible for increasing the allowable TIT have been made mainly through innovations in cooling technology, specifically convective cooling schemes. An emerging manufacturing technology may further facilitate the increase of allowable maximum TIT, thereby impacting cycle efficiencies. Laser Additive Manufacturing (LAM) is a promising manufacturing technology that uses lasers to selectively melt powders of metal in a layer-by-layer process to directly manufacture components, paving the way to produce designs that are not possible with conventional casting methods. This study investigates manufacturing qualities seen in LAM methods and its ability to successfully produce complex microfeatures in a mock turbine blade leading edge. Various cooling features are incorporated in design, consisting of internal impingement cooling, internal lattice structures, and external showerhead cooling. The internal structure is designed as a lattice of intersecting cylinders in order to mimic that of a porous material. Through a non-destructive approach, the presented design is analyzed against the departure of the design by utilizing X-ray computed tomography (CT). Employing this non-destructive testing (NDT) method, a more thorough analysis of the quality of manufacture is established by revealing the internal structures of the porous region and internal impingement array. Variance distribution between the design and manufactured test article are carried out for both internal impingement and external transpiration hole diameters from CT data. Flow testing is performed to characterize the uniformity of porous regions and flow behavior across the entire article for various pressure ratios. Discharge coefficients of internal impingement arrays and porous structures are quantified. A numerical model of fluid flow through the exact CAD geometry is analyzed over the range of experimental flowrates. By comparison of experimental and numerical data, performance discrepancies associated with manufacturing quality are observed. Simplifying assumptions to the domain are evaluated to compare predictions of CFD using the exact geometry. This study yields quantitative data on the build quality of the LAM process, providing more insight as to whether it is a viable option for manufacture of micro-features in current turbine blade production.
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Date Issued
2016
Identifier
CFE0006452, ucf:51428
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006452
Design, Development, and Testing of a Miniature Fixture for Uniaxial Compression of Ceramics Coupled with In-Situ Raman Spectrometer
Title
Design, Development, and Testing of a Miniature Fixture for Uniaxial Compression of Ceramics Coupled with In-Situ Raman Spectrometer.
Creator
Jordan, Ryan, Orlovskaya, Nina, Kwok, Kawai, Ghosh, Ranajay, University of Central Florida
Abstract / Description
This thesis is about the design, development and integration of an in-situ compression stage which interfaces through the Leica optical microscope coupled with a Renishaw InVia micro-Raman spectrometer. This combined compression stage and Raman system will enable structural characterization of ceramics and ceramic composites. The in-situ compression stage incorporates a 440C stainless steel structural components, 6061 aluminum frame, a NEMA 23 stepper motor. Two load screws that allow to...
Show moreThis thesis is about the design, development and integration of an in-situ compression stage which interfaces through the Leica optical microscope coupled with a Renishaw InVia micro-Raman spectrometer. This combined compression stage and Raman system will enable structural characterization of ceramics and ceramic composites. The in-situ compression stage incorporates a 440C stainless steel structural components, 6061 aluminum frame, a NEMA 23 stepper motor. Two load screws that allow to apply compressive loads up to 14,137 N, with negligible off axis loading, achieving target stresses of 500 MPa for samples of up to 6.00 mm in diameter. The system will be used in the future to study the structural changes in ceramics and ceramic composites, as well as to study thermal residual stress redistribution under applied compressive loads. A broad variety of Raman active ceramics, including the traditional structural ceramics 3mol%Y2O3-ZrO2, B4C, SiC, Si3N4, as well as exotic materials such as LaCoO3 and other perovskites will be studied using this system. Calibration of the systems load cell was performed in the configured state using MTS universal testing machines. To ensure residual stresses from mounting the load cell did not invalidate the original calibration, the in-situ compression stage was tested once attached to the Renishaw Raman spectrometer using LaCoO3 ceramic samples. The Raman shift of certain peaks in LaCoO3 was detected indicative of the effect of the applied compressive stress on the ceramics understudy.
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Date Issued
2019
Identifier
CFE0007824, ucf:52809
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007824