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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Do more mergers and acquisitions create value for the firm?

Li, Shaomeng January 2015 (has links)
This thesis is aimed to empirically investigate the performance impact of frequent acquisitions as an aggressive merger and acquisition (M&A) strategy for an acquiring firm. In literature related to the study of M&A, a common question is whether acquisitions improve the performance of acquirers. Neither theoretical nor empirical studies have a clear view on the performance effect of M&A. Some argue positively and some are opposite. Although existing research are mixed for their arguments, a takeover is commonly perceived as a shock to the firm with a constant effect on changing business performance. This static perception of M&A creates a difficulty in explaining why firms acquire others when the performance effect is negative. To address the issue, this thesis examines the M&A effect dynamically with taking into account the role of merger frequency in affecting performance. On the basis of a large sample that consists of about 14,000 acquisitions from more than 100 countries over last 12 years, the thesis finds that the investors perceive a lower value if the acquiring firm is involved in frequent mergers. This is because more mergers are expected to attract considerable amount of management attention away from profitable activities in order to digest the challenges of new business integration at least in the short run. This “digesting constraint” argument is evident by our estimations. Firm becomes less profitable in the short run after a merger shock, and this adverse effect can be more severe if the firm is involved in more frequent mergers. Evidence of the thesis further show that, the effect of merger shocks is not static and persistent, and it changes with time. The shock affects adversely profitability in the short run, usually lasting a couple of years, and then the negative effect on performance could be turned either oppositely if the firm digests the shock successfully, or otherwise, continuously but diminishing over time if the digestion takes longer such as for frequent acquisition. This finding implies that the pace of firm resilience to a merger shock can be affected by its merger strategies. The pace can be slow if the firm pursues frequent mergers aggressively. The performance effect of a merger shock is dynamic and changes with time. The dynamic view for merger shocks from this study opens a new vision for literature in merger studies. Overall the market expectation to a merger effect on changing firm performance is quite consistently related to what has actually happened to the firm after the merger shock.
12

Dynamic Testing and Finite Element Modeling of a Steel Girder Bridge for the Long-Term Bridge Performance Program

Taveras Moronta, Lourdes Alina 01 May 2012 (has links)
The majority of the bridges in the United States are already reaching the years that the design process took into account when determining the time the structure would be functional. This means that many of the bridges in the nation are in need of increasing maintenance, and in some cases, major retrofitting. Researchers at Utah State University in conjunction with the Long-Term Bridge Performance (LTBP) Program, under the direction of the Federal Highway Administration’s (FHWA’s) Office of Infrastructure Research and Development, directed dynamic testing on the New Jersey Pilot Bridge, structure number 1618-150. The purpose of the LTBP Program is to monitor the nation’s highway bridges for a 20-year period to analyze and understand the behavior over time of the selected bridges and then promote the safety, mobility, longevity, and reliability on those bridges. In order to perform the monitoring of the bridge, ambient vibration analysis was selected for this structure, which was instrumented with an array of velocity transducers to record the response coming from the excitation. A finite element model was also created to compare the results from the ambient vibration testing. The results of this testing will be used with the LTBP Program to improve the knowledge of the bridge performance and foster the next generation of bridges and bridge management in the nation.
13

Prediction of long-term creep behavior of epoxy adhesives for structural applications

Feng, Chih-Wei 01 November 2005 (has links)
The mechanical property of polymeric materials changes over time, especially when they are subjected to long-term loading scenarios. To predict the time-dependent viscoelastic behaviors of epoxy-based adhesive materials, it is imperative that reliable accelerated tests be developed to determine their long-term performances under different exposed environments. A neat epoxy resin system and a commercial structural adhesive system for bonding aluminum substrates are investigated. A series of moisture diffusion tests have been performed for more than three months in order to understand the influence of the absorbed moisture on creep behavior. The material properties, such as elastic modulus and glass transition temperature, are also studied under different environmental conditions. The time-temperature superposition method produces a master curve allowing the long-term creep compliance to be estimated. The physics-based Coupling model is found to fit well the long-term creep master curve. The equivalence of the temperature and moisture effect on the creep compliance of the epoxy adhesives is also addressed. Finally, a methodology for predicting the long-term creep behavior of epoxy adhesives is proposed.
14

Prediction of long-term creep behavior of epoxy adhesives for structural applications

Feng, Chih-Wei 01 November 2005 (has links)
The mechanical property of polymeric materials changes over time, especially when they are subjected to long-term loading scenarios. To predict the time-dependent viscoelastic behaviors of epoxy-based adhesive materials, it is imperative that reliable accelerated tests be developed to determine their long-term performances under different exposed environments. A neat epoxy resin system and a commercial structural adhesive system for bonding aluminum substrates are investigated. A series of moisture diffusion tests have been performed for more than three months in order to understand the influence of the absorbed moisture on creep behavior. The material properties, such as elastic modulus and glass transition temperature, are also studied under different environmental conditions. The time-temperature superposition method produces a master curve allowing the long-term creep compliance to be estimated. The physics-based Coupling model is found to fit well the long-term creep master curve. The equivalence of the temperature and moisture effect on the creep compliance of the epoxy adhesives is also addressed. Finally, a methodology for predicting the long-term creep behavior of epoxy adhesives is proposed.
15

Two Essays on Stock Repurchases-The Post Repurchase Announcement Drift: An Anomaly in Disguise? and Intra Industry Effects of IPOs on Stock Repurchase Decisions

Nguyen, Thanh Thiet 01 January 2013 (has links)
We reexamine the stock price drifts following open-market stock repurchase announcements by differentiating actual repurchases from repurchase announcements and by controlling for the repurchasing firms' earnings improvement in the announcement year relative to the prior year. Our results show that only firms that actually repurchase their shares exhibit a positive post-announcement drift. More importantly, we find that these repurchasing firms have the same post-announcement drift as their matching firms that have similar size and earnings performance but do not repurchase. Further analysis indicates that the post-repurchase announcement drift is not a distinct anomaly but the well-documented post-earnings announcement drift in disguise. In addition, previous studies suggest that the market perceives IPOs as bad news (i.e., competitive threats) to existing firms in the same industry. At the same time, the market has a tendency to be overly optimistic about IPO prospects, especially during hot IPO markets. Thus, the negative industry rival reaction could be the result of investors' over-optimism toward the IPOs' growth prospects and underestimation of the competitive positions of industry rivals. Our findings show that rival firms use repurchases as a means to signal their firm quality, as well as to correct the market's overreaction to the bad news. These IPO-induced repurchases are stronger when the rival firms are in a concentrated industry and experienced poor stock performance in the previous year.
16

Experimental investigation of aging effect on damping ratio of high damping rubber bearing

Muratani, Keiichi, Kito, Satoshi, Itoh, Yoshito, Kitane, Yasuo, Paramashanti 01 August 2011 (has links)
No description available.
17

LONG-TERM PERFORMANCE EVALUATION OF HIGH DAMPING RUBBER BEARINGS BY ACCELERATED THERMAL OXIDATION TEST

Gu, Haosheng, Kitane, Yasuo, Itoh, Yoshito, Paramashanti 12 1900 (has links)
2nd International Conference on Advances in Experimental Structural Engineering, Tongji Univ., Shanghai, China, December 4-6, 2007
18

Estudo da influÃncia dos parÃmetros operacionais na eletrodeposiÃÃo de camadas eletrocatalÃticas de ligas de Ni-Fe. / Study the influence of operating parameters in the electrodeposition of layers of eletrocatalÃticas alloys of Ni-Fe.

Josenir Barreto de Sousa 13 July 2007 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O presente trabalho mostra o estudo da influÃncia da radiaÃÃo de ultra-som sobre a eletrodeposiÃÃo de ligas de Ni-Fe. Foram avaliados a estabilidade e o desempenho eletrocatalÃtico das ligas para a ReaÃÃo de Desprendimento de HidrogÃnio (RDH) em meio alcalino. As ligas eletrodepositadas de Ni-Fe foram obtidas em soluÃÃo 0,06 mol.dm-3 de Ni2SO4.6H2O, 0,48 mol.dm-3 de Na3C3H5O7.2H2O, 0,71 mol.dm-3 de Na2CO3 e 0,16 mol.dm-3 (banho 1) e 0,04 mol.dm-3 de FeSO4.7H2O (banho 2). Foi adicionado 8,4 mL.L-1 de H2SO4 para manter o pH abaixo de 1. A eletrodeposiÃÃo foi realizada sob controle galvanostÃtico variando-se a densidade de corrente de 10 mA.cm-2 a 50 mA.cm-2, na temperatura ambiente (≡ 28ÂC) e de 55ÂC na presenÃa e na ausÃncia da radiaÃÃo de ultra-som. Todos os revestimentos foram depositados em um disco de aÃo-carbono com Ãrea geomÃtrica exposta de 0,7 cm2. A RDH foi estudada em soluÃÃo de NaOH 0,5 mol.dm-3. Foi utilizada para todos os experimentos o eletrodo auxiliar de Pt e o eletrodo de referÃncia de Hg/HgO, OH- (0,5 mol.dm-3). Os revestimentos foram caracterizados por Microscopia EletrÃnica de Varredura (MEV), Voltametria CÃclica (VC) e as propriedades eletrocatalÃticas das ligas de Ni-Fe foram avaliadas por Curva de PolarizaÃÃo de Tafel e por OperaÃÃo ContÃnua. Os resultados mostraram que o ultra-som aumentou a quantidade de Fe eletrodepositada e as ligas obtidas sob a aÃÃo da radiaÃÃo de ultra-som apresentaram o melhor desempenho para a RDH. / The present work shows the study of the ultrasound irradiation influence in the electrodeposition of Ni-Fe coatings. The electrocatalytic performance of these coatings for the hydrogen evolution reaction (her) in alkaline medium was also evaluated. The Ni-Fe coatings were obtained from plating solutions containing 0.06 mol.dm-3 Ni2SO4.6H2O, 0.48 mol.dm-3 Na3C3H5O7.2H2O, 0.71 mol.dm-3 Na2CO3 and 0.16 mol.dm-3 (bath 1) and 0.04 mol.dm-3 FeSO4.7H2O (bath 2). It was also added 8.4 mL L-1 H2SO4 to maintain the pH below 1. The electrodepositions were carried out under galvanostatic control in the range of 10 mA cm-2 to 50 mA cm-2, at room temperature (≈ 28ÂC) and at 55ÂC in the presence and in the absence of ultrasound irradiation. All coatings were deposited on disk mild steel substrate with an exposed geometric area of 0.7 cm2. The hydrogen evolution reaction was studied in 0.5 mol.dm-3 NaOH. In all electrochemical experiments Pt was the auxiliary electrode and Hg/HgO, OH- (0,5 mol.dm-3) was the reference one. The coatings ware characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and the electrocatalytic properties of the Ni-Fe coating were evaluated by Tafel polarization and long-term performance tests. The results showed that the use of the ultrasound irradiation leads to an increase of the Fe content in the electrodeposits. Additionally, the coatings obtained in presence of ultrasound also present the best performance for her.
19

Temperature Effects On Integral Abutment Bridges For The Long-Term Bridge Performance Program

Rodriguez, Leo E. 01 May 2012 (has links)
The United States Department of Transportation (US-DOT) Federal Highway Administration (FHWA) initiated in 2009 the Long-Term Bridge Performance (LTBP) program to gather high-quality data on a representative sample of bridges over a twenty-year period of time. The goal of this program is to quantify how bridges behave during their service life while being exposed to different types of loadings and deterioration due to corrosion, fatigue and various climate conditions along with their corresponding maintenances. The data gathered will result in the creation of databases of high quality data, acquired through long-term instrumentation, to be used for improved design practices and effective management of infrastructures by employing best practices for maintenance. As part of the LTBP Program two integral abutment bridges, a California Bridge near Sacramento, CA and a Utah Bridge near Perry, UT, were selected to be monitored for temperature changes as well as to undergo periodic live-load testing. Live-load testing included slowly driving a truck over the bridges. The bridges were instrumented to collect test data and use it to calibrate a finite-element model. This finite-element model was used to determine the actual bridge behavior and compare it with the AASHTO LRFD Specifications. This thesis also examined how different parameters such as thermal gradients, mean temperature, and end-rotation affect these two integral abutment bridges.
20

Investigation of Chip Seal Aggregate Retention using Sweep and Long Term Performance Testing

Alvarado, Alejandro Jose 11 August 2012 (has links)
Chip seals are a commonly used surface treatment used to decrease the deterioration rate of pavement surfaces. Chip seals typically consist of an application of emulsion and cover aggregate. Failure can be driven by improper strength development and inadequate bonding over time. Additionally, chip seal service life varies and long term performance prediction models are not well established. This study has two primary goals. The first goal is to investigate aggregate retention characteristics of chip seal specimens, while investigating material compatibility by means of the Sweep-M test. The second goal is to begin developing a long term performance (LTP) test to represent cores obtained from full-scale chip seal projects. Conditioning and testing protocols for LTP specimens are evaluated for representative chip seal behavior over long periods. Results confirm material interaction and favor the incorporation of sweep testing for optimum performance. Future testing is recommended for in-depth, LTP test protocol evaluation.

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