Design Procedures and Finite Element Analysis of Pot Bearings

RÉSUMÉ Au Canada, les infrastructures des ponts vieillissent rapidement. En 2007, un grand nombre de ponts ont dépassé 57% de leur durée de vie, estimée à 43,3 années. Ce ratio augmenté 72% au Québec, ce qui indique qu’un bon nombre de ces ponts sont structurellement ou fonctionnellement déficient (Gagnon and Gaudreault 2011). Ce contexte met l’accent sur la nécessité de ce baser sur la performance, la rentabilité et l’optimisation des techniques de construction et l’amélioration des stratégies de rénovation. L’appui du pont est un élément essentiel de l’ensemble de la structure. Étant donné que la durée de vie d’un appui de pont est plus courte que celle du pont lui-même, un nombre considérable de déficiences dans les ponts peut être dû à un dysfonctionnement de l’appui du pont. Le type d’appui du pont qui est largement utilisé est un appui de type pot (élastomère confiné), qui a été développé en Europe au début des années 1960. Comme d’autres types d’appuis, l’appui de type pot est utilisé pour supporter une superstructure de pont et accommoder ses mouvements indépendamment des éléments de support, c’est-à-dire piles et culées (Tonias 1994).----------ABSTRACT Bridge infrastructure in Canada is aging rapidly, with a large number of bridges exceeding 57% of their service life estimated at 43.3 years in 2007 (Gagnon and Gaudreault 2011). This ratio increases to 72% in Quebec, indicating that many of these bridges are structurally or functionally deficient. This context emphasizes the need for performance-based, cost-effective and optimized construction techniques and retrofit strategies. A bridge bearing is a crucial part of the whole structure. Since the total lifetime of a bearing is much less than that of the bridge itself, considerable number of deficiencies in bridges can be due to bearing malfunction. A widely used type of bridge bearings are elastomeric pot bearings (EPBs), which are developed in Europe in the early 1960s. As other bearing types, they are used to support a bridge superstructure and accommodate its movements independently from the supporting elements, i.e. piers and abutments (Tonias 1994)

Simulation of low velocity impact on composite hemispherical shell

Impact simulation with finite element analysis is an appropriate manner to reduce the cost and time taken to carry out an experimental testing on a component. In this study, the impact behavior of the composite hemispherical shell induced by low velocity impact is simulated in ABAQUS software with finite element method. To predict the responses of Kevlar fabric/polyester, glass fabric/polyester and carbon fabric/polyester in the form of a hemisphere, once as one layer and then as a three-layered composite under applied force by an anvil. The sequences of layers are changed, to investigate and compare the occurred alternations in the amount of energy absorption, impact force and specific energy absorption (SEA). The comparison of results showed that the highest and the lowest quantity of energy absorption and SEA belong to Carbon/Glass/Kevlar (CGK) and Kevlar/Carbon/Glass (KCG) respectively

Failure prediction and availability-based maintenance planning of gas transmission pipelines

As the most frequent failure source, external corrosion has led to more than 1700 failures in gas transmission pipelines in US since 1996, causing a property damage of approximately $189M. Such numbers highlight the importance of maintaining gas transmission pipelines in safe conditions to postpone corrosion failures. As the most widely applied method of corrosion monitoring technique, in-line inspection is expensive and time-consuming due to requiring high frequencies. On the other hand, the recent efforts directed towards developing failure prediction or maintenance planning models for oil and gas pipelines seem to have some limitations. As such, most of the failure prediction models are based on limited number of inspection or historical records or are limited in application due to their subjectivity. Furthermore, in the domain of maintenance planning, the current procedures are merely based on considering the associated costs and safety thresholds in the decision-making process. Such methodologies do not address the importance of pipeline availability and continuation of operation as a critical asset in the selection of the maintenance strategy. This research has two main objectives. As the first objective, the proposed research aims to develop historical data-based failure prediction models for gas transmission pipelines by considering geo-environmental features. As the second objective, this research aims to propose a reliability-centered availability-based maintenance planning framework that considers the criticality of pipeline operation. For these objectives, a detailed literature review was carried out on current methodologies to predict failures in oil and gas pipelines and maintain them. As the most important limitations, current failure prediction models do not consider geographical and environmental properties of pipelines to predict failures. On the other hand, in maintenance planning scope, none of current practices highlight importance of pipeline operation and availability in making the proper decision. In addition, these methodologies are often subjective, i.e. they are merely applicable to limited pipelines. To overcome these limitations the mentioned objectives of this research were defined and failure and maintenance data were collected from accessible historical records and reports. The failure prediction models were developed from best-subset and multiple regression analyses on the historical failure data and were then validated. On the other hand, the maintenance planning framework was developed from a coupled cost and availability-based maintenance planning procedure on different maintenance scenarios. For each scenario, a discrete event simulation was carried out through MATLAB programming. Such simulation was performed on the pipeline reliability profile obtained from a Monte Carlo simulation and consideration of improvement in availability per unit cost as the decision criteria. Monte Carlo simulation was carried out to consider wide range of design parameters for development of the reliability profile. The developed failure prediction models were able to satisfactory predict time of corrosion failures in gas transmission pipelines for Great Plains and South East Regions of the U.S. These models were validated with mean absolute error (MAE) and root mean square error (RMSE) of 0.12 and 0.04, for Great Plains, and 0.11 and 0.07, for South East regional classifications, respectively. The proposed maintenance planning framework reveals that for a case study of a 24-inch pipeline, considering an availability-cost indicator, the second maintenance scenario, with interventions at the service life of 30.1 and 40.5 years is more effective. This order is followed by the first scenario with interventions at service life of 33.3 and 42.2 years, and finally the third scenario with intervention at service life of 24.2 years, respectively. The developed failure prediction models can assist decision makers and pipeline operators to predict the expected time of corrosion failure in gas transmission pipelines in the selected regions by considering geo-environmental and pipeline design parameters. In addition, for maintenance planning of oil and gas pipelines, this research proposes a novel methodology that considers oil and gas pipelines as critical assets for which continued operation is of high importance. Such consideration provides a compensation between the costs incurred and pipeline availability to avoid over/under maintenance

Alienation of Rural Youth in South Dakota

There are two purposes of this research. The first purpose is to assess the presence of alienation in a sample of rural youth. The second purpose is to assess the relationship between the occurrence of alienation among rural youth and their plans for out- migration. The problem of concern in this project is addressed in terms of three questions. First, are rural youth alienated? Second, if alienation exists among rural youth, who is alienated? Third, if alienation exists among rural youth, does this experience relate to migration plans? Seeman\u27s conceptualization of alienation as powerlessness, normlessness and isolation is applied in a theoretical framework derived primarily from the work of Durkheim and Merton. Alienation is observed among a sample of rural South Dakota youth and is found to be associated with several variables. Major findings are these : (1) rural female high school students are more alienated than male high school students; (2) those with high GPA\u27s show the higher level of alienation; (3) highly alienated rural high school students are more likely to have plans for out-migration than less alienated students; (4) alienation accounts for little of the variance in rural youth\u27s migration plans; and (5) alienation is a more meaningful factor in the plans of female and of students who report lower GPA\u27s

Quantitative proteomics in resected renal cancer tissue for biomarker discovery and profiling

<b>Background:</b>  Proteomics-based approaches for biomarker discovery are promising strategies used in cancer research. We present state-of-art label-free quantitative proteomics method to assess proteome of renal cell carcinoma (RCC) compared with noncancer renal tissues.<p></p> <b>Methods:</b>  Fresh frozen tissue samples from eight primary RCC lesions and autologous adjacent normal renal tissues were obtained from surgically resected tumour-bearing kidneys. Proteins were extracted by complete solubilisation of tissues using filter-aided sample preparation (FASP) method. Trypsin digested proteins were analysed using quantitative label-free proteomics approach followed by data interpretation and pathways analysis.<p></p> <b>Results:</b>  A total of 1761 proteins were identified and quantified with high confidence (MASCOT ion score threshold of 35 and P-value <0.05). Of these, 596 proteins were identified as differentially expressed between cancer and noncancer tissues. Two upregulated proteins in tumour samples (adipose differentiation-related protein and Coronin 1A) were further validated by immunohistochemistry. Pathway analysis using IPA, KOBAS 2.0, DAVID functional annotation and FLink tools showed enrichment of many cancer-related biological processes and pathways such as oxidative phosphorylation, glycolysis and amino acid synthetic pathways.<p></p> <b>Conclusions:<b>  Our study identified a number of differentially expressed proteins and pathways using label-free proteomics approach in RCC compared with normal tissue samples. Two proteins validated in this study are the focus of on-going research in a large cohort of patients.<p></p&gt

Interaction effects of zinc and manganese on growth, uptake response and chlorophyll content of sweet corn (Zea mays var. saccharata)

Manganese (Mn) and Zinc (Zn) interact with each other and this interaction can result in impacts on the yield of corn plants. This study was conducted to examine the effect of different levels of Mn and Zn on the yield, Mn and Zn concentration, root growth parameters and chlorophyll contents of corn plants. Sweet corn was grown in nutrient culture containing all combinations of Zn and Mn at levels of 0.0, 0.1, 1.0 and 10.0 mg L-1 as ZnSO4.7H2O and MnSO4.H2O, respectively and harvested at 28 days after transplanting. Mn and Zn concentrations in roots and shoots increased with increasing Mn and Zn concentration in nutrient solution. Zn concentration in both roots and shoots enhanced with increasing Mn levels. Mn concentration in shoots did not show any correlation with Zn concentration in nutrient solution, but Mn concentration in roots decreased with increasing levels of Zn. Zn0Mn1 treatment produced the highest yield. The lowest dry weight of young corn plants was recorded under Zn10Mn0 treatment due to Mn deficiency. Chlorophyll content decreased with high Zn application and this can be attributed to the interaction of Zn with iron in the growth medium. Different levels of Zn and Mn in nutrient solution did not have any significant effect on root parameters

Extraction and preparation of bamboo fibre-reinforced composites

Natural plant fibre composites have been developed for the production of a variety of industrial products, with benefits including biodegradability and environmental protection. Bamboo fibre materials have attracted broad attention as reinforcement polymer composites due to their environmental sustainability, mechanical properties, and recyclability, and they can be compared with glass fibres. This review classifies and describes the various procedures that have been developed to extract fibres from raw bamboo culm. There are three main types of procedures: mechanical, chemical and combined mechanical and chemical extraction. Composite preparation from extracted bamboo fibres and various thermal analysis methods are also classified and analysed. Many parameters affect the mechanical properties and composite characteristics of bamboo fibres and bamboo composites, including fibre extraction methods, fibre length, fibre size, resin application, temperature, moisture content and composite preparation techniques. Mechanical extraction methods are more eco-friendly than chemical methods, and steam explosion and chemical methods significantly affect the microstructure of bamboo fibres. The development of bamboo fibre-reinforced composites and interfacial adhesion fabrication techniques must consider the type of matrix, the microstructure of bamboo and fibre extraction methods

A Comparative Study of Mathematical Models for Migration of Pesticides in Surface and Subsurface Waters

Proceedings of the 1991 Georgia Water Resources Conference, March 19-20, 1991, Athens, Georgia.Development, validation, and application of mathematical models for evaluating fate and transport of pesticide in the environment have received considerable attention during recent years. Mathematical modeling provides a conceptually valid and meaningful approach to integrate environmental properties and chemical processes affecting ecological and/or human health. Additionally, modeling results can be used by Federal and State Regulatory Agencies to support registration decisions or generally planning decision-making efforts. A part of this comprehensive management-oriented modeling process is the simulation of transport and transformation of pesticides in agricultural watersheds. A number of models have been developed during the last decade and are used widely as predictive tools for assessing the impact of pesticides on surface and groundwater quality. Usually these models are used as screening tools to evaluate a new pesticide or an existing one used in a specific agricultural area which may pose an environmental problem. The models are also useful as management tools for assessing the effects of agricultural management practices on non-point source pollution control. In this study, comparisons between two well known pesticide loading models are performed. Model predictions are compared for a number of parameters, including surface runoff, soil erosion, and mass transport of two herbicides in surface runoff and in the soil profile. Given the ability of both models for potential use for environmental risk assessment problems, historical data were used in order to estimate frequency distributions of the pesticide mass reaching the edge of the field and leaching from the crop root zone.Sponsored by U.S. Geological Survey, Georgia Department of Natural Resources, the University of Georgia, Georgia State University, and Georgia Institute of Technology.This book was published by the Institute of Natural Resources, The University of Georgia, Athens, Georgia 30602 with partial funding provided by the U.S. Department of the Interior, Geological Survey, through the Georgia Water Research Institute as authorized by the Water Resources Research Act of 1984 (P.L. 98242). The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of The University of Georgia or the U.S. Geological Survey or the conference sponsors

Insulin Receptor Isoform A and Insulin-like Growth Factor II as Additional Treatment Targets in Human Osteosarcoma

Abstract Despite the frequent presence of an insulin-like growth factor I receptor (IGFIR)-mediated autocrine loop in osteosarcoma (OS), interfering with this target was only moderately effective in preclinical studies. Here, we considered other members of the IGF system that might be involved in the molecular pathology of OS. We found that, among 45 patients with OS, IGF-I and IGFBP-3 serum levels were significantly lower, and IGF-II serum levels significantly higher, than healthy controls. Increased IGF-II values were associated with a decreased disease-free survival. After tumor removal, both IGF-I and IGF-II levels returned to normal values. In 23 of 45 patients, we obtained tissue specimens and found that all expressed high mRNA level of IGF-II and >IGF-I. Also, isoform A of the insulin receptor (IR-A) was expressed at high level in addition to IGFIR and IR-A/IGFIR hybrids receptors (HRA). These receptors were also expressed in OS cell lines, and simultaneous impairment of IGFIR, IR, and Hybrid-Rs by monoclonal antibodies, siRNA, or the tyrosine kinase inhibitor BMS-536924, which blocks both IGFIR and IR, was more effective than selective anti-IGFIR strategies. Also, anti–IGF-II-siRNA treatment in low-serum conditions significantly inhibited MG-63 OS cells that have an autocrine circuit for IGF-II. In summary, IGF-II rather than IGF-I is the predominant growth factor produced by OS cells, and three different receptors (IR-A, HRA, and IGFIR) act complementarily for an IGF-II–mediated constitutive autocrine loop, in addition to the previously shown IGFIR/IGF-I circuit. Cotargeting IGFIR and IR-A is more effective than targeting IGF-IR alone in inhibiting OS growth. [Cancer Res 2009;69(6):2443–52