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.

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.

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.

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.

No description available.

2nd International Conference on Advances in Experimental Structural Engineering, Tongji Univ., Shanghai, China, December 4-6, 2007

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.

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.

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.

Context The number of Initial Public Offerings on the Swedish market has increasedrapidly over the last decade, reporting over 100 IPOs only in 2021. Although theincrease has been extraordinary, the majority of the IPO performance researchhas been conducted on larger markets such as the US, Germany, and China. Thiscreates a gap in the research regarding the performance of IPOs on the fastgrowing Swedish stock market.  Purpose The purpose of this thesis is to fill the identified research gap and examine howthe Swedish IPOs perform in relation to established firms listed on the OMXSSmall Cap. Findings on long-term over-or underperformance would lay afoundation for potential investment strategies as well as show signs ofinformation asymmetry and mispricing. To further extend the use of ourfindings, firm-specific factors will be tested in a regression model to find ifspecific firm characteristics have a positive or negative impact on the long-termperformance of the IPOs.  Questions at issue 1. Does the Swedish Initial Public Offerings over/underperform comparedto the OMXS Small Cap in the long run? 2. Which firm-specific factors affect the long-term performance of an IPO? Methodology To find if the IPOs over-or underperform the OMXS Small Cap index, the Buyand Hold Abnormal Returns over 24 and 36 months are calculated with theOMXS Small Cap as a benchmark index. Further, a regression analysis with 15explanatory variables is performed with the received BHAR results as thedependent variable to find if there are any significant relationships between thefirm-specific variables measured before the IPO and the long-term performance.  Results The Buy and Hold Abnormal Returns presented a positive abnormal return forboth periods measured, with a significant overperformance of 9,91% over the36-month period, and 21,14% for the 24-month period. Further, the regressionanalysis showed a positive relationship between firm performance and firm sizeand Return On Equity, indicating that a high ROE, as well as a larger firm sizeat the date of the listing, increases the chances of higher long-term returns.