Theses

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  • Synchronous Generator Excitation Control Based on Model Predictive Control
    Synchronous Generator Excitation Control Based on Model Predictive Control
    This thesis research has designed and developed an optimal predictive excitation control, named the Model Predictive Excitation Control (MPEC), for utility generators. Four significant results are achieved: First, the MPEC has been designed and has significantly improved the classical model predictive control and is much simpler and computationally efficient. Second, the MPEC simulation program and results have been accomplished, and study cases have demonstrated the effectiveness of the MPEC. Third, the Modified classical model predictive control procedure has been formulated to correct a timing error such that the controlling input for the present time is re-written as that for the next step. Fourth, the MPEC optimization formulation and procedure has been developed for the generator control with only two substation-ready-available measurements which are the generator terminal voltage and speed.
    Synchronous collaborative 3D GIS with agent support
    Synchronous collaborative 3D GIS with agent support
    3D geographical information systems (GIS) software tools that support synchronous collaboration efforts among distributed decision-making participants can be very useful in many application areas, such as urban planning, engineering design, disaster and emergency management, and subsurface resources management. Although research has been extensively carried out in related fields such as groupware system, collaborative virtual environments and collaborative industrial design, a comprehensive study has not been found in the 3D GIS field. The scientific goal of this research is to add synchronous collaboration capability to the Internet-enabled 3D GIS environment. More specifically, the ojbective of this research is to investigate methods and key technologies to design a synchronous collaborative Internet-enabled 3D GIS environment (SC3DGIS).In this thesis, two basic questions for synchronous collaborative 3D GIS are presented: 1) What are the special functions and usability for SC3DGIS compared to traditional and mainstream GIS applications? 2) What are the special problems in design and development of SC3DGIS when considering it as a specific type of synchronous collaborative system? In answering the above two questions, a conceptual framework is developed to investigate main aspects which play core roles in reflecting the features of SC3DGIS. The more detailed system requirements are further analyzed through a case study. The prototype design adopts two layer structures - the shared 3D environment layer and the agent assistant layer. The shared 3D environment adopts a semi-replicated architecture, while in the agent assistant layer, a multi-agent method is used to solve the complex interactions between users and the shared understanding of all parties in the framework. Two walkthroughs are presented to validate the usability of the prototype.The results of this research indicate that 1) adding synchronous and collaborative capabilities to a 3D GIS environment can significantly improve the efficiency and satisfaction of decision-making for the geographically-distributed people; 2) the events transferring method and semi-replicated architecture are more suitable for synchronous collaborative 3D GIS than a display imagery transferring method and centralized architecture because of the highly interactive 3D contents; 3) a 3D data model for collaborative purposes require explicit data state presentations, such as color and style; 4) a social collaboration model and its ontology presentation and shared catching method keep the distributed system consistent and understandable; and 5) a multi-agent method sitting on a shared 3D view can be very helpful in assisting group users to carry out more complex communications, such as discussions and making deals.
    Synergistic Cisplatin-induced cell death by ultrasound-microbubble mediated intracellular delivery in breast cancer cells.
    Synergistic Cisplatin-induced cell death by ultrasound-microbubble mediated intracellular delivery in breast cancer cells.
    Ultrasound-microbubble (USMB) potentiated cisplatin (CDDP) therapy was assessed in human breast cancer cells. Cells, MDA-MB-231, in suspension were exposed to USMB and CDDP at varying conditions, during which microbubble cavitation activity was measured using passive cavitation detection and 48 hours post-treatment cell viability and intracellular platinum concentration were measured using MTT assay and mass cytometry, respectively. USMB synergistically enhanced cell death (~20 fold) when combined with CDDP and significantly increased intracellular CDDP concentration (~8 fold) compared to CDDP treatment alone. Cell death and intracellular CDDP concentration were correlated to microbubble cavitation activity, which increased with peak negative pressure and microbubble concentration. Combined treatment of USMB and CDDP at relatively lower integrated cavitation dose (ICD) induced a synergistic effect on cell death whereas ICD greater than 10 induced an additive effect. USMB mediated CDDP intracellular accumulation synergistically enhances cell death in CDDPresistant breast cancer cells.
    Synthesis Of Molecular Probes For Cystic Fibrosis Research
    Synthesis Of Molecular Probes For Cystic Fibrosis Research
    Cystic fibrosis (CF) is caused by mutations in the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. In healthy individuals, CFTR acts as a phosphorylation and nucleotide regulated channel which mediates the flux of chloride ions across the membrane of epithelial cells. The most common genetic lesion is deletion of phenylalanine residue 508 (F508del-CFTR). The mutation leads primarily to misfolding of the protein, resulting in degradation of most of the protein before it reaches the cell membrane. Also, any F508del-CFTR in the membrane exhibits reduced ion channel activity. The drug-like small molecule VRT-532 has been shown to improve both the trafficking of F508del-CFTR to the cell membrane, as well as its channel function. The exact nature of the interaction of VRT-532 with mutant CFTR is not fully understood. The goal of this research is to help reveal the nature of interaction between VRT-532 and mutant CFTR protein by synthesizing derivatives useful in biochemical studies. Understanding the molecular basis for this interaction will provide us with a template for the development of therapeutically efficacious compounds.
    Synthesis Of Nanoparticle Networks By Femtosecond Laser Ablation Of Microparticles
    Synthesis Of Nanoparticle Networks By Femtosecond Laser Ablation Of Microparticles
    The process of laser ablation has been adapted to generate nonoparticles from microparticles of the material, referred to as laser ablation of microparticles (LAM). The LAM process has been shown to generate finer nanoparticles than were previously possible through laser ablation of solid targets. In this thesis, a method of generating a 3D nanoparticle network using the LAM process has been proposed using a femtosecond laser. 3D naoparticles were successfully generated through ablation of microparticle samples of lead oxide, nickel oxide and zinc oxide. The size of the nanoparticles in the generated network was significantly reduced in comparison with similar networks generated through laser ablation of solid targets. The method has been further extended to generate a unique alloy nanomaterial through the ablation of the microparticle containing powders of two metals (Aluminum and Nickel Oxide).
    Synthesis and Application of Chiral Palladium-Phosphane Precatalyst in Enantioselective C-N Cross-Coupling
    Synthesis and Application of Chiral Palladium-Phosphane Precatalyst in Enantioselective C-N Cross-Coupling
    The various strategies and reaction conditions towards the synthesis of benzene-, naphthalene-, and phenanthrene-based dicyclohexylbiaryl phosphanes are presented. A chiral third generation Buchwald-type precatalyst has been synthesized, employing the non-commercially available ligand, (R)-dicyclohexyl(2'-methoxy-[1,1'-binaphth-2-yl])phosphane, (R)-Cy2MOP, and a dimeric methanesulfonate-bridged palladacycle based on a 2-aminobiphenyl scaffold. Application of the palladacyclic precatalyst in an enantioselective variant of the BuchwaldHartwig reaction is demonstrated in the desymmetrization of prochiral α-(2-bromobenzyl)malonamides via intramolecular N-arylation. The scope of the catalysis in the presence of the precatalyst has been investigated with efforts towards optimizing yields, catalyst loading, and enantioselectivities. Attempts towards the isolation of a potential reaction intermediate in the form of a stable amido-bound palladium complex are discussed. Finally, strategies towards gaining mechanistic insight on the origin of the enantiomeric excess are discussed.
    Synthesis and Investigation of Perfluorinated Polystannanes
    Synthesis and Investigation of Perfluorinated Polystannanes
    Two fluorinated tetraaryl stannanes, 1 and 2 were synthesized in good yields. X-ray crystallography revealed deviation from ideal tetrahedral geometry with C-Sn-C bond angles between 107.89°-112.7° for 1 and 104.69°-120.76° for 2. Dichlorides 4 and 5 were synthesized using a redistribution reaction between SnC1₄ and 1-2. These dichlorides also deviated from tetrahedral geometry with bond angles between 101.79°-128.44° for 4 and 99.23°-125.9° for 5. Polymerizaton of 4 and 5 by Wurtz coupling produced polymers 10 and 11. Absolute molecular weights in the range of 1.16 x 10⁵-2.92 x 10⁷ Da was estimated for 10 and 1.47 x 10⁵ Da for 11. UV/VIS spectroscopy gave values of 332 nm and 328 nm that are blue shifted to other polystannanes. The unexpected cleavage of a tin-aryl bond produced tin trihydrides 8 and 9. Polymerization of 8-9 produced the network polymers 12 and 13 with [wavelength]max values of 354 nm and 350 nm.
    Synthesis and characterization of ferrocenyl stannanes and polyferrocenyl stannanes
    Synthesis and characterization of ferrocenyl stannanes and polyferrocenyl stannanes
    A novel polymer polybis(dimethyl stannyl)ferrocene was synthesized through both metal catalyzed intermolecular dehydrogenative condensation and ring-opening polymerization. This polymer was the first evidence of a dibridged polyferrocenyl stannane, and was found to be of low to moderate molecular weight by gel permation chromatography and 1H NMR spectroscopy. This polymer displayed extensive electronic communication observed previously synthesized monobridged ferrocenyl stannane polymers. The first tristanna-bridged 3.3]ferrocenophane was discovered through an amine coupling of a tin amine, and 1,1’bis(dimethyl stannyl) ferrocene. The [3.3]ferrocenophane displayed a strong interaction between connected ferrocenes despite the large distance, (8.49 Å) between Fe centers. Finally, a new and improved synthesis of 1,1,2,2-tetramethyldistanna-[2]ferrocenophane was found. This metal catalyzed intramolecular dehydrogenative coupling employs Pd2(dba)3 as a catalyst and yields 90% product. All products were characterized where possible 1H, 13C, and 119Sn NMR and UV-Visible spectrocopy, as well as through cyclic voltammetry and DFT modeling.
    Synthesis and characterization of theranostic agents for photoacoustic imaging and therapy.
    Synthesis and characterization of theranostic agents for photoacoustic imaging and therapy.
    In this work, phase-change contrast agents were developed for photoacoustic (PA) imaging and therapy. They consist of superheated liquid perfluorocarbon and gold nanoparticles capped by a Poly-(Lactide-co-Glycolic Acid) (PLGA) polymer shell. The phase transition from liquid to gas bubble can be remotely triggered by a laser source. In their liquid state, upon laser irradiation, these agents generated strong PA signals which were proportional to the laser fluence and particle sizes. The vaporization threshold decreased with increasing particle size, and was 850, 670 and 420 mJ/cm2 for 2, 5, 10 μm-sized PLGA particles loaded with 35 nm GNPs, respectively. Cell culture studies, including passive uptake by the cancer cells and mechanical damage to the cancer cells caused by the vaporization inside the cells are also investigated. These agents show potential as photoacoustic imaging contrast and cancer therapy agents for clinical applications.
    Synthesis and structure-property studies of organic dyes possessing unique fused thiophene π-spacers
    Synthesis and structure-property studies of organic dyes possessing unique fused thiophene π-spacers
    This thesis examines the synthesis of metal-free organic dyes for light-harvesting applications within the DSSC manifold. All DSSC organic dyes possess a similar donor-π-spacer-acceptor (D-π-A) motif. Here, triphenylamine (TPA) is employed as a donor owing to its redox stability and cyanoacetic acid has been utilized as an acceptor due to its electron-withdrawing ability. Thiophenes are ubiquitous in organic materials chemistry owing to their exceptional charge transport behavior, and in this body of work, π-spacers incorporating benzodithiophene and thiophene-quinones have been incorporated into a DSSC dye and their utility explored. Fused thiophene cores are non-innocent π-spacers. Non-innocent, in this context, is defined as π-spacers that incorporate a secondary chromophore or redox active species (benzodithiophene or quinone).
    Synthesis of Classical and Non-Classical CMOS Transistor Fault Models Mapped to Gate-Level for Reconfigurable Hardware-Based Fault Injection
    Synthesis of Classical and Non-Classical CMOS Transistor Fault Models Mapped to Gate-Level for Reconfigurable Hardware-Based Fault Injection
    One of the main goals of fault injection techniques is to evaluate the fault tolerance of a design. To have greater confidence in the fault tolerance of a system, an accurate fault model is essential. While more accurate than gate level, transistor level fault models cannot be synthesized into FPGA chips. Thus, transistor level faults must be mapped to the gate level to obtain both accuracy and synthesizability. Re-synthesizing a large system for fault injection is not cost effective when the number of faults and system complexity are high. Therefore, the system must be divided into partitions to reduce the re-synthesis time as faults are injected only into a portion of the system. However, the module-based partial reconfiguration complexity rises with an increase in the total number of partitions in the system. An unbalanced partitioning methodology is introduced to reduce the total number of partitions in a system while the size of the partitions where faults are to be injected remains small enough to achieve an acceptable re-synthesis time.
    Synthesis of Metal-Coordinating Arenediynes And Study Of Their Reactivity in Bergman Cyclization
    Synthesis of Metal-Coordinating Arenediynes And Study Of Their Reactivity in Bergman Cyclization
    The Bergman cycloaromatization (BC) in which a cis-alkene-1,2-diyne (enediyne) cyclizes to form a p-benzyne diradical, typically is a very endothermic reaction, requiring a substantial amount of energy (i.e. high temperature) for it to proceed. This reaction received very little attention until a decade after its discovery, when the natural enediynes were isolated and shown to be the most active antitumor agents every discovered. Having BC at the heart of their mode of action, these natural enediynes have been very challenging to mimic from synthetic standpoints. Of particular interest is to be able to design and synthesize an enediyne that is stable at room temperature, while also being capable of being triggered to undergo BC under ambient conditions. Although a relatively new concept, metal-induced BC reactions have generally been known to decrease the demanding energy barrier. The work presented here describes several synthetic strategies towards arenediyne crown eithers and the synthesis of several arenediyne hydrazone/Schiff base ligands with extended n-systems. These synthesized enediynes are useful ligands, capable of metal-cordination and hence potentially decreasing the BC energy barrier. BC reactions of enediyne intermediates are also reported.