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Designing Hydrogen Bonding Polyesters, and Their Use for Enhancing Shape Fidelity of 3D Printed Soft ScaffoldsQianhui, Liu January 2019 (has links)
No description available.
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Development of New Cobalt Pincer Complexes for Catalytic Reduction ReactionsLi, Yingze 18 October 2019 (has links)
No description available.
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Building a Green Living : Measuring the green bond premium on the Swedish real estate marketAlldén, Pontus, Joshi, Dev January 2021 (has links)
Background: With the first green bond being issued in 2008 as a joint venture between World Bank Organization and the Swedish bank SEB the financial instrument has made an impact on the financial markets. With a high demand for sustainable investments in Sweden partly due to policies a premium for the green bonds is to be expected at least according to theory. The real estate market has adapted to the increased demand for green investments by moving more towards green bonds, and rightfully so as it is one of the largest polluters seen by sector. In result, it is also one of the largest issuers of bonds which creates an excellent opportunity to research the industry as there is plenty of data available. Purpose: This report will examine the premium of green bonds in the Swedish real estate market. Furthermore, it will also examine the effects of Covid-19 and to what extent this pandemic had an impact on green bonds. Method: The thesis examines the Option Adjusted Spread (OAS) of 166 bonds of 9 different companies from the start of 2016 to December 2020 within the Swedish real estate market. Control variables such as Company risk, Market risk and Macroeconomic variables were used in an OLS regression to estimate the premium. The effect of the Covid-19 pandemic was also examined. Conclusion: After analyzing 53 green and 113 conventional bonds no significant results were found on how premium differs between green and conventional bonds. However more general findings were found that suggest bonds become more sought during the Covid-19. It was further found that the green bond market is rapidly growing and may in a few years be in a better position to be examined.
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Účtování vybraných problémů na kapitálovém trhu / Selected Problem Accounting on Capital MarketPaseková, Petra January 2009 (has links)
The purpose of this thesis is to describe the accounting practices of selected problems on the capital markets. I have processed the accounting procedures through practical demonstrations of the chosen company and the selected problems. The aim is to demonstrate accounting of these problems and transfer the knowledge into practice.
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Fluorinated Alcohols : A Perfect Medium for Direct Functionalization of Aromatics / Alcools fluorés : un milieu parfait pour la fonctionnalisation directe d'aromatiquesTang, Renjin 03 October 2018 (has links)
Le trifluoroéthanol (TFE) et l'hexafluoroisopropanol (HFIP) présentent des propriétés physicochimiques particulières comme un fort pouvoir ionisant élevé, une forte capacité à donner des liaisons hydrogène, et une faible nucléophilie. Ces différentes propriétés ont été avantageusement exploitées dans plusieurs réactions sans la présence de catalyseur. Dans un premier temps, l'étude de l'amination électrophile sélective d'aromatiques avec les azodicarboxylates a été réalisée dans l'HFIP pour conduire à une famille d'hydrazines aromatiques. Ensuite l'alkylation de Friedel-Crafts avec des hétéroaromatiques et des β-nitroalcènes a conduit à des dérivées de tryptamines. Ensuite, l'halogénation sélective d'aromatiques et d'hétérocycles en présence de N-halosuccinimides (NIS, NBS et NCS) a été développée. Egalement, nous avons étudié un nouveau système combinant l'HFIP et le KHSO4 qui est un sel inorganique peu coûteux. L'association de l'HFIP et de KHSO4 (10 mol%) est un système catalytique doux et efficace pour promouvoir certaines réactions. En particulier nous avons montré que ce système catalytique a été appliqué avec succès pour l'amination directe d'aromatiques peu activés avec des azodicarboxylates pour conduire à d'autres dérivés hydrazines. Ce système a aussi montré son efficacité dans la réaction directe de benzylation de Friedel-Crafts avec des alcools benzyliques. Ainsi une grande variétés de composés diarylméthanes dissymétriques a pu être obtenue avec une excellente régiosélectivité. / Due to the electron-withdrawing character of fluoroalkyl groups, fluorinated alcohols such as trifluoroethanol (TFE) and hexafluoroisopropanol (HFIP) exhibit a nearly unique set of properties that include high ionizing power, strong hydrogen bond donating ability, mild acidity, and low nucleophilicity. All of these properties have been exploited without the need of an external catalyst. At first, the para-selective amination of free anilines with azodicarboxylates in HFIP led to hydrazine derivatives. The Friedel-Crafts alkylation of indoles and electron-rich arenes with β-nitroalkenes succeeded to afford tryptamines derivatives. Then the regioselective halogenation of arenes and heterocycles with N-halosuccinimides (NIS, NBS, NCS) have been developed. Meanwhile, we have disclosed a new mild system between HFIP and KHSO4 which is a green, inexpensive and readily available inorganic salt. The association of HFIP/KHSO4 (10 mol%) is an efficient and mild catalytic system in order to promote some reactions. In particular, we showed that this system allowed the direct amination of slightly activated and neutral arenes with azodicarboxylates in order to give other families of hydrazines. This mild system has been applied successfully for the Friedel-Crafts benzylation with benzylic alcohols. These mild conditions provided a straightforward synthesis of a variety of unsymmetrical diarylmethanes in high yield with good to high regioselectivity
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Evaluation of Strand to Grout Bond in Post-Tensioned Tendons with Corrosion Inhibiting PenetrantsKupselaitis, Kurt 13 March 2019 (has links)
Post tensioning bridges is an efficient way of construction where segments of a bridge are strung together using small diameter high strength strands. The steel strands are passed through internal and/or external ducts within the concrete segments, jacked to high levels of stress, anchored using steel wedges, and then filled with a corrosion inhibiting filler. A cementitious material called grout has been widely used for over 50 years as this filler. The Federal Highway Administration design and construction manual provides recommendations in the properly filling techniques to ensure the tendons are full of grout. Despite the level of detail the manual provides, several Florida bridges that used this construction technique have seen severe corrosion related failures due to poor grout quality.
Oil based products have been developed for the express purpose of reducing the corrosion rate in previously grouted tendons. Utilizing the interstitial spaces in the steel strands, low viscosity fluid is pumped through the strand which can also penetrate the surrounding grout and fill unintentional voids. However, by doing so, there is the concern that the bond strength could be compromised and increase the risk of failure.
This study presents the findings of small scale grouted mono-strand tendons which determined the bond effects of defective grout, evaluated the injection capabilities of various penetrants, and determined whether or not the penetrant adversely affects bond after impregnation. No appreciable variation in bond was found.
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Development of In-situ Nanocrystalline NiCoCrAlTaY Coatings by Cold Spray on a Single-Crystal Nickel-base Superalloy for Gas Turbine ApplicationsGuo, Deliang 15 April 2021 (has links)
MCrAlY coatings are commonly applied as the bond coat in TBCs used in modern gas turbines. Cold spray (or CS), characterized by low process temperature and high particle impact velocity, has been demonstrated as a promising alternative to thermal spray processes, such as air plasma spray (APS) and high velocity oxygen fuel (HVOF), for manufacturing MCrAlY coatings. The general objective of the thesis research is to characterize CS deposition on a single-crystal nickel-base superalloy and to develop low-cost/high-performance NiCoCrAlTaY coatings using the CS technique.
Several individual studies were carried out with each having a specific focus towards achieving the general research objective. CS deposition of NiCoCrAlTaY coatings using nitrogen was first examined to verify the feasibility of replacing the expensive helium gas typically used as the CS process gas. Several materials were used as the substrates, and the effects of substrate materials and surface preparation on coating microstructure and properties were investigated. Recycling of non-deposited powder particles was then explored to reduce the costs associated with the feedstock powder. A cost model that includes the economics of powder recycling was developed for the CS process, showing that the use of nitrogen and powder recycling could potentially be cost-effective for CS deposition of MCrAlY coatings.
A CS process that can produce in-situ nanocrystalline NiCoCrAlTaY coatings was proposed to develop coatings with enhanced oxidation performance. This CS approach utilizes conventional commercial powders instead of pre-milled nanocrystalline powders. Detailed characterization using the scanning electron microscope (SEM), scanning transmission electron microscope (STEM), and X-ray diffraction (XRD) was carried out to investigate the microstructure of the resulting CS NiCoCrAlTaY coatings, single-crystal substrate, and their interface. Isothermal oxidation performance of the CS NiCoCrAlTaY coatings was evaluated at 1100°C for 1h to 500h. Results revealed that the nanostructure promoted the α-Al2O3 scale formation and sustained α-Al2O3 scale growth, suggesting good isothermal oxidation performance.
Finally, the effects of different processing sequences on CS NiCoCrAlTaY coating characteristics and short-term isothermal oxidation performance were investigated. Specifically, CS deposition of NiCoCrAlTaY coatings was carried out on single-crystal superalloy substrates that underwent various degrees of full heat treatments prior to being coated. The remaining superalloy heat treatments required were then performed on the coated samples after the CS deposition. The microstructures of the superalloy substrates and CS NiCoCrAlTaY coatings were characterized after each heat treatment. Isothermal oxidation performance of the coated samples following different sequences was evaluated at 1100°C for 2 hours. The results suggested a promising processing sequence that could potentially further improve the oxidation performance of CS NiCoCrAlTaY coatings.
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The Effects of Transverse Reinforcement on the Strength and Deformability of Reinforced Concrete ElementsKinsey C Skillen (9768341) 15 December 2020 (has links)
Post-earthquake examinations of reinforced concrete structures often show structural damage resulting from bond and shear failures. Such failures typically occur in reinforced concrete elements with details known to cause problems, such as widely spaced transverse reinforcement and/or lap splices located in regions of flexural yielding. These details are common in older reinforced concrete buildings (built before 1970) that have reinforced concrete columns with longitudinal reinforcement spliced just above the floor level, and transverse reinforcement spaced at a distance of d/2 or longer. This investigation focused on means to increase the deformability of existing reinforced concrete elements susceptible to bond and shear failures during a seismic event or other applications requiring toughness. The effects of confinement provided by epoxied anchors, spiral transverse reinforcement, and post-tensioned external clamps were investigated. Emphasis was placed on producing a strengthening device that can be sized, fabricated, and installed with ease because most of the existing strengthening techniques require specialized labor, tools, and materials. The observations collected support the idea that active confinement provided by post-installed and post-tensioned transverse reinforcement was the most effective method to improve structural deformability among the methods studied and within the ranges considered.
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Evaluation of Bond Strength between Overlay and Substrate in Concrete RepairsNeshvadian Bakhsh, Keivan January 2010 (has links)
Good bond strength between overlay and substrate is a key factor in performance of concrete repairs. This thesis was aimed at studying the evaluation of bond strength between repair material and substrate at the interface. Many factors such as surface roughness, existence of micro cracks, compaction, curing etc influence the bond strength. The quality assurance of the bond strength requires test methods that can quantify the bond strength as well as identify the failure mode. There have been numerous investigations led to development of different test methods. The forces which are applied in each test and the failure mode are important in order to choose the proper test. An interpretive study on test methods is presented. While this study can provide individually useful information on bond strength and bond characterization, it also contains discussions about each test and comparison of test methods.
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Essays in Financial EconomicsSiani, Kerry Yang January 2022 (has links)
This dissertation studies topics in financial economics. In the first chapter, Raising Bond Capital in Segmented Markets, I study the cost of bond capital. The cost of bond capital to firms that is determined at issuance often exceeds yields trading in secondary bond markets. I find that the difference between yields at issuance and in secondary markets, the ``issuance premium'', spikes in bad times, increasing firms' costs of capital. This suggests that the economics of the relatively understudied primary bond markets -- where firms sell new bonds via underwriters to investors -- are important for understanding firms' costs of capital and access to credit over the cycle. Leveraging new data on bond issuance, I estimate a model of primary markets that explains the issuance premium and its impact on bond issuance volume. Using high-frequency variation in bond supply as an instrument, I find that investors are more sensitive to issuance premiums than the remainder of credit spreads. As issuance premiums rise in bad times, the share of more price-elastic short-term investors endogenously increases, supporting bond volumes. The preferences of primary market investors therefore directly affect the transmission of shocks to firms' costs of capital and bond issuance volume, as well as the price impacts of corporate bond purchase policies.
The second chapter, Bond Market Stimulus: Firm-Level Evidence from 2020-21, is co-authored with Olivier Darmouni. We use micro-data on corporate balance sheets to study firm behavior after the unprecedented policy support to corporate bond markets in 2020. We find that as bond yields fell, firms issued bonds to accumulate large and persistent amounts of liquid assets instead of investing. Conceptually, the benefits depend on how highly bond issuers valued this liquidity at the margin. We show they generally had access to bank liquidity that they chose not to use: many issuers left their credit lines untouched, while others used bonds to repay existing loans. Moreover, equity payouts remained high: almost half of issuers still repurchased shares in Spring 2020.
In the third chapter, Global Demand Spillovers: the Role of Underwriting Networks, I study the role of underwriter networks in transmitting demand shocks across global jurisdictions. Using novel data and a difference-in-differences strategy, I find that central bank corporate bond purchases spill over to foreign jurisdictions through bond underwriting networks. The diff-in-diff exploits the European Central Bank's 2016 corporate sector purchase program. I compare U.S. firms connected to underwriters with more or less Eurozone clients. Firms connected with banks with more European clients had larger orderbooks and issued more at lower costs. Treated firms do not increase real investment, but rather increase equity payouts. I identify bond underwriting networks as a novel channel through which demand shocks spread across borders. These results matter for understanding the overall impact of corporate quantitative easing programs.
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