Alumina-titanium diboride (Al2O3-TiB2) composites have high temperature, wear, and impact resistance that could be useful in high performance applications. Determining the effect of processing parameters on relative bond strength and effective plasticity may contribute to optimization and predictability of performance in the Al2O3-TiB2 system. Al2O3-TiB2 composites were obtained from a collection of samples that were created during a separate ongoing research program being conducted by Dr. Kathryn V. Logan. The Logan samples were initially formed by hot pressing powders produced using Self-Propagating High Temperature synthesis (SHS) of Al, TiO2, and B2O3 powders or manual mixing (MM) of Al2O3 and TiB2 powders. Samples were then fractured using standard single edge notched beam (SENB) fracture toughness testing. The obtained fractured surfaces were examined using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Relative amounts of transgranular and intergranular fracture of Al2O3 and TiB2 grains were determined. Transgranular fracture was used as a measure of relative bond strength. Other samples were obtained from the Logan collection to conduct nano-indentation measurements on polished sample surfaces in Al2O3 grains and in TiB2 grains. Indent locations were verified using SEM. Reduced modulus, final displacements, and fracture toughness for indents in Al2O3 grains and in TiB2 grains were determined from nano-indentation curves. Reduced modulus was used as a measure of relative bond strength. Final displacement and fracture toughness were used as measures of relative effective plasticity. Analysis of Variance (ANOVA) using Taguchi arrays was conducted using the powder processing factor (SHS vs. MM) and the predominant microstructure factor (TiB2 grains surrounding Al2O3 grains vs. TiB2 grains distributed amongst Al2O3 grains) when examining the effect of processing parameters on relative bond strength as measured by amount of transgranular fracture. Analysis of Variance (ANOVA) using Taguchi arrays was conducted using the powder processing factor (SHS vs. MM), the predominant microstructure factor (TiB2 grains surrounding Al2O3 grains vs. TiB2 grains distributed amongst Al2O3 grains), and the indented phase factor (Al2O3 vs. TiB2) when examining the effect of processing parameters on relative bond strength as measured by nano-indentation reduced modulus and both measures of relative effective plasticity. Powder processing was significant for the relative bond strength measures, but was not significant for the relative effective plasticity measures. Predominant microstructure was significant for all measures except relative effective plasticity as measured by fracture toughness, for which none of the factors and interactions were significant. The interaction between powder processing and predominant microstructure was significant for most of the relative bond strength measures and for relative effective plasticity as measured by final displacements. Indented phase was significant for the nano-indentation measures except nano-indentation fracture toughness, although the significance for nano-indentation fracture toughness was just below the critical level. The interaction between powder processing and indented phase and the interaction between predominant microstructure and indented phase were only significant for the relative bond strength measure using nano-indentation reduced modulus. The interaction between powder processing, predominant microstructure, and indented phase was significant for the nano-indentation measures except nano-indentation fracture toughness. The optimum level for powder processing was predominantly manual mixing. The optimum level for predominant microstructure was predominantly TiB2 grains surrounding Al2O3 grains. The optimum level for indented phase was predominantly TiB2. / Master of Science

Vehicle suspensions have been a major focus of research and design since the introduction of the automobile. The two major characteristics that define the performance of a specific suspension design are the vehicle ride and handling. A simplified view of chassis development is that a desirable vehicle ride is provided by a "soft" suspension, and desirable vehicle handling is provided by "stiff" suspensions, it is impossible to simultaneously maximize both vehicle ride and handling in a passive suspension design. However, with the introduction of active components, such as actuators and semiactive dampers, coupled with dynamic control strategies, a more desirable compromise between the benefits of soft and stiff suspensions can be achieved. The purpose of this research is not to create a better suspension, but to investigate how active control can improve vehicle ride. As with any research area, a method for evaluating new ideas is required. Many computational methods exist for determining the ride performance of various suspension designs, however computational results alone can be hard to interpret and often deceiving. The following thesis outlines the design and validation of an experimental test rig for evaluating fully active or semi-active suspension algorithms. The test rig utilizes a fully active electromagnetic actuator which can simulate the performance characteristics of fully active as well as semi-active components which a suspension design may utilize. The demonstration rig couples visual inspection with computational analysis and provides the tools necessary for the designer to accurately interpret the ride performance of a new design and simultaneously compare it with a passive design. The goal is to provide a visual development platform in which new algorithms can be quickly and easily implemented and compared against existing algorithms to determine the performance characteristics of each on a physical system. The test rig demonstrated its ability to test both fully-active and semi-active skyhook control algorithms, and accurately simulated both fully-active and semi-active suspension components. The test rig provides a simple and cost effective way to evaluate new algorithms both computationally and visually on a physical system. / Master of Science

Thesis (M.B.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2999-01-01

Doctor of Education / Department of Educational Leadership / David C. Thompson / The purpose of this study was to analyze opinions of selected school district stakeholders regarding potentially critical factors in school bond referendum success and failure in Kansas during the years 2004-2007. Of the 72 eligible school districts, one district was randomly selected from each of six groups formed through a stratified random sampling process utilizing district enrollment (small, medium, large) and bond election result (successful, unsuccessful). Four purposefully selected respondents from each district participated in a mixed methods strategy of inquiry that included completing a 32-item written survey and participating in a personal interview. The survey served as the standardized data collection instrument. Survey data were used to augment and expand upon understanding of the bond referendum process gained from the personal interviews by examining respondents‟ perceptions of how important campaign strategies were, or would have been, in influencing election results. Frequency distributions were constructed in an attempt to identify relationships between variables identified as important to bond election success. Cross-tabulations and Pearson's chi-square were the statistical treatments chosen to further analyze the survey data. During the interviews, participants were asked a set of standard questions as well as questions unique to their role in the election process. The questions were designed to elicit in-depth responses about factors critical to the bond's success or failure and to gather useful advice for other districts preparing for a bond election. Interviews were used to discover new data, further develop existing data, and assist in organizing all data sources to construct a "story" describing bond election experiences in Kansas. The study findings indicate that unsuccessful districts utilize more campaign strategies and perceive them to be more important than successful districts, but that successful districts are more in tune with patrons. As each district is unique, it was found that strategies that were successful in one district might not be in another. Three factors found to be critical included: having unanimous school board support for the bond referendum, developing an on-going public relations strategy with patrons, and communicating the elements of a bond referendum to all patrons in simple, clear, and honest language.

The purpose of this study was to investigate the capital project financing methods of Texas community college districts, including an analysis of successful general obligation bond elections. A two-phase research approach was used in this analysis. The first part of the research investigation surveyed 65 community college executives and administrators representing 50 community college districts in Texas. College leaders were asked to participate in an online survey regarding finance methods used to fund capital projects. This included leaders who have participated in general obligation bond referendums on their college campuses. Thirty-four out of 65 leaders responded to the survey, which resulted in a 52.3% response rate. The second part of the investigation disaggregated survey response information from district college leaders into two groups: Those who finance capital projects utilizing general obligation bonds (GO bond) and those who use other methods than general obligation bonds to fund capital improvements or renovations. A cross-sectional study was conducted during the second phase, which investigated 12 community college district leaders’ processes and strategies of passing general obligation bond elections from 1998 to 2008. As a follow-up to the survey instrument, 11 interviews were conducted from GO and non-GO bond community college districts. The results from the findings led to the following conclusions. Each community college district is unique in how capital projects are funded. The commonalities that existed among survey participants and the personal interviews conducted were establishing strong community relationships prior to the planning of bond campaigns. The data reinforced the basic premise of building key relationships with civic/business leaders early on in the process. The importance of creating an environment that focuses on open communication and trust in support of the college was a determining factor for winning bond elections. The recommendations that emerged from this study were community college leaders must begin a dialogue to share best practices in capital project funding. Secondly, community college leaders must advocate for an organized system of data collection to record general obligation bond elections from their state agencies. Lastly, an organization for capital project advocacy must be created. / text

Non-covalent interactions taking place in solution are essential in chemical and biological systems. The solvent environment plays an important role in determining the geometry and stability of interactions. This thesis examines aromatic stacking interactions, alkyl-alkyl interactions, edge-to-face aromatic interactions, halogen bonds and hydrogen…hydrogen interactions in solution. Chapter 1 briefly introduces the different classes of non-covalent interactions, in addition to the state-of-the-art models and methods for investigating these weak interactions. The chapter finishes with a focus on dispersion interaction in alkanes and arenes. Chapter 2 investigates dispersion interactions between stacked aromatics in solution using a new class of complexes and thermodynamic double mutant cycles (DMCs). In extended aromatics, dispersion was detected as providing a small but significant contribution to the overall stacking free energies. Chapter 3 concerns the experimental measurement of alkyl-alkyl dispersion interactions in a wide range of solvents using Wilcox torsion balances. The contribution of dispersion interactions to alkyl-alkyl association was shown to be very small, with DMC, QSPR method and Hunter's solvation model. Chapter 4 studies edge-to-face aromatic interactions in series of solvents. In the open system, edge-to-face aromatic interactions were found to be sensitive to the solvent environment. The solvent effects were complicated and cannot be rationalised by a single parameter. Further analysis is needed. Chapter 5 describes a preliminary approach to investigate organic halogen…π interactions in solution using supramolecular complexes and torsion balances. Chapter 6 is a preliminary investigation of the ability of hydrogen atoms to act as H bond acceptors in silane compounds. Computations and 1H NMR demonstrated a weak interaction between silane and perfluoro-tert-butanol.

Purpose: To compare the in-vitro shear bond strengths of a new paste-paste formulation of resin-modified glass-ionomer cement (Rm-GIC) to an exising powder-liquid formulation. The study will test the hypothesis that the new paste-paste formulation of Rm-GIC (Fuji-Cem ™, GC Corp, Tokyo, Japan) has the same bond strength as an existing popular powder-liquid formulation of Rm-GIC (Rely-X ™ Luting Cement, 3M, St. Paul, MN)Materials and Methods: A total of 33 human molars were sectioned parallel to the occlusal surface to expose mid-coronal dentin and mounted parallel to the bond shearing device on the universal testing machine (Instron). For Group I samples (Rely-X, n=15), the powder and liquid were measured and adjusted to achieve a ratio of 1.6 and mixed for 30 seconds as recommended by the manufacturer. For Group II (Fuji-Cem, n=18), the paste-paste was expressed from the paste-dispenser provided by the manufacturer and mixed for 10 seconds as recommended. After testing, the teeth from group II were bonded on a different site with the same material but mixed for 20 seconds (n=18). To ensure a uniform flow and bond surface area, the mixed cement was syringed into a cylindrical mould (diameter 2.38mm, height 2mm) and allowed to set under constant force. All samples were subjected to fracture by shear loading on a universal testing machine (Instron) at a uniform crosshead speed of .02" per minute and expressed as MPa. Values were analyzed at the pResults: Wilcoxon rank sums test showed significantly higher shear bond strength values for Rely-X compared to Fuji-Cem mixed both at 10 seconds and 20 seconds. Mixing for 20 seconds resulted in stronger bonds for Fuji-Cem compared to 10 seconds, but was still significantly lower than Rely-X.Conclusions: Within the limitations of the study, the Rely-X powder-liquid formula shows a significantly stronger dentin shear bond strength when compared to the new paste-paste formula of resin-modified glass ionomer cement, Fuji-Cem.

Carbonyl complexes of Ni(0) incorporating two N-heterocyclic carbenes of the type Ni(CO)2(NHC)2 (NHC = ICy [N, N'-bis(cyclohexylimidazol)-2-ylidene], IMes [N, N'- bis(2, 4, 6-trimethylphenyl)-imidazol)-2-ylidene]) have been prepared. The complexes Ni(CO)2(ICy)2 (8) and Ni(CO)2(IMes)2 (9) have been synthesized and characterized by single crystal X-ray diffraction. The enthalpy of substitution reactions of Ni(CO)2(NHC) (NHC = ItBu [N, N'-bis(tert-butylimidazol)-2-ylidene], IAd [N, N'-bis(1- adamentylimidazol)-2-ylidene]) with NHC and tertiary phosphine ligands leading to the formation of Ni(CO)2(L)2 (L = NHC, PR3) complexes have been determined. The solution calorimetric investigations reiterate the greater electron donating property of the NHC ligands compared to tertiary phosphines. Thermochemical studies of the substitution reactions of Ni(CO)2(NHC) (NHC = ItBu, IAd) forming complexes (8) and (9) led to the determination of average bond dissociation energy of Ni-NHC (NHC = ICy, IMes) and Ni-P (P = PCy3, PPh3, P(p-Tol)3, P(m-Tol)3).

Associant l’analyse du discours esthétique des auteurs comme Müller, Bond et Barker, à l’étude dramaturgique de leurs réécritures respectives de Shakespeare, cette thèse a pour but de s’interroger sur l’émergence d’une nouvelle forme dramatique – la dystopie théâtrale. En faisant appel à l’instrumentalisation de la catastrophe, à la fois shakespearienne et historique, les dramaturges s’empressent à écrire des pièces qui partagent presque la même vision sur l’avenir du monde et de l’homme. L’apocalypse du roi Lear et la vision cauchemardesque qu’Hamlet porte sur le monde sont greffées, par les dramaturges, sur des tissus dramatiques étayés déjà sur les traces des barbaries du XXe et XXIe siècles. En tant qu'écritures résolument catastrophistes, les « dystopies théâtrales » s’opposent, à première vue, à toute fonction utopique. Néanmoins, le ton apocalyptique (au sens derridien du terme) qui les caractérise, cache des fonctions esthétiques qui questionnent à nouveau la catharsis et la nature même du théâtre. En analysant ces fonctions, nous tentons de démontrer que ces formes dramatiques peuvent être vues aussi comme des dramaturgies censées provoquer l’éveil des consciences et ressusciter ainsi la pulsion utopique que l’Humanité semble avoir perdue. En plus d’une épuration émotionnelle (qui elle-même est remise en question), la dystopie théâtrale est aussi caractérisée par une catharsis inversée, dans le sens d’une surcharge intellective et d’une rétention émotionnelle qui touche souvent le paroxysme. Quel lien entre l’Utopie et la « dystopie théâtrale » ? / This thesis emphasizes the emergence of a new dramaturgical form – the theatrical dystopia. The study analyses the aesthetical discourse of authors such as Heiner Müller, Edward Bond and Howard Barker, as well as their contemporary rewritings of some of Shakespeare’s plays. Through their conceptualization of the Catastrophe, both Shakespearian and historical, these authors seem to have the same vision of the future of the world and the humans. King Lear’s apocalypse and the nightmarish “Hamletian” vision of the world are grafted on modern literary “tissues”, which are already imbued with the traces of the catastrophes from twentieth and the twenty-first century. Theatrical dystopias seem opposed to every utopian function. Nevertheless, le ton apocalyptique (Derrida) which characterizes them hides aesthetical functions, which cast new meanings to the catharsis notion and the nature of the theatre. By analyzing these functions by and large, this study shows that these new dramaturgical forms are to be seen as writings that highlight awareness and resuscitate the utopian impulse that the Humanity seems to have lost. Despite a strong emotional discharge (which also acquires new functions), theatrical dystopias are also characterized by inverse catharsis – a cerebral and emotional retention which often touches paroxysm. What is thus the connection between Utopia and theatrical dystopia?

Thesis advisor: Pierluigi Balduzzi / Thesis advisor: Jonathan Reuter / In the first essay of this dissertation, I study the impact of fund redemptions and resulting sell-offs on corporate bond yields. To control for unobserved changes in fundamentals, I study within-issuer variation of yield changes, resulting from differential exposure to redemptions and sell-offs. In contrast to previous findings for equity funds, I find no evidence indicating that bond funds destabilize the corporate bond market by moving prices beyond fundamental values. I attribute this finding to bond fund management. Although I find that investors demonstrate a bank-run like behavior, which is a potential source of destabilization, bond fund managers hold a significant level of liquid assets, allowing them to manage redemptions without excessively liquidating corporate bonds. Second essay of this dissertation looks at corporate bond Exchange Traded Funds (ETFs) which are a new form of financial innovation. Since these investment vehicles are relatively new, little is known about their risks. In this paper, we study an event in the summer 2013, knows as the Taper Tantrum, when bond ETFs and mutual funds experienced massive unexpected outflows due to speculations about interest rate hikes. We find that ETF outflows during the Taper Tantrum lead to a significant increase in exposed corporate bond yields. The increase in yields lasts for seven months, which indicates a temporary fire sale effect. In contrast, we find no fire sale effect resulting from mutual fund outflows. We attribute this contrasting finding between the two vehicles to differences in portfolio construction and investor sensitivities. Finally, we study arbitrage opportunities, created by ETF shares mispricing, and their impact on bond yields. Third essay of this dissertation is about liquidity in the corporate bond market. In market distress, corporate bond investors tend to sell liquid assets and hold onto illiquid ones, a phenomenon which we call flight to illiquidity. We study the impact of flight to illiquidity on corporate bond prices/yields in cross-section as well as corporate bond returns in time-series. First, we show that liquidity price premium disappears in market distress, meaning that liquid bonds are not more expensive than illiquid bonds in distress times. Second, we show that illiquiduity return premium which exists during normal times, not only does not change sign or disappears, but also widens in market distress. In other words, liquid bonds deliver a lower return both on average and during market distress. This pattern is limited to investment grade corporate bonds. Our findings suggest that keeping the credit risk fixed, liquid bonds do not provide safety during the time it is needed the most. / Thesis (PhD) — Boston College, 2016. / Submitted to: Boston College. Carroll School of Management. / Discipline: Finance.