Monitoring and model updating of an FRP pedestrian truss bridge

This paper presents the results of a real bridge field experiment, carried out on a fiber reinforced polymer (FRP) pedestrian truss bridge of which nodes are reinforced with stainless steel plates. The aim of this paper is to identify the dynamic parameters of this bridge by using both conventional techniques and a model updating algorithm. In the field experiment, the bridge was instrumented with accelerometers at a number of locations on the bridge deck, recording both vertical and transverse vibrations. It was excited via jump tests at particular locations along its span and the resulting acceleration signals are used to identify dynamic parameters, such as the bridge mode shape, natural frequency and damping constant. Pedestrianinduced vibrations are also measured and utilized to identify dynamic parameters of the bridge. For a complete analysis of the bridge, a numerical model of the FRP bridge is created whose properties are calibrated utilizing a model updating algorithm. Comparable frequencies and mode shapes to those from the experiment were obtained by the FE models considering the reinforcement by increasing elastic modulus at every node of the bridge by stainless steel plate. Moreover, considering boundary conditions at both ends as fixed in the model resulted in modal properties comparable/similar to those from the experiment. This study also demonstrated that the effect of reinforcement and boundary conditions must be properly considered in an FE model to analyze real behavior of the FRP bridge.

An innovative electroforming process for oil heated rotational moulding tools

Rotational moulding is a method to produce hollow plastic articles. Heating is normally carried out by placing the mould into a hot air oven where the plastic material in the mould is heated. The most common cooling media are water and forced air. Due to the inefficient nature of conventional hot air ovens most of the energy supplied by the oven does not go to heat the plastic and as a consequence the procedure has very long cycle times. Direct oil heating is an effective alternative in order to achieve better energy efficiency and cycle times. This research work has combined this technology with new innovative design of mould, applying the advantages of electroforming and rapid prototyping. Complex cavity geometries are manufactured by electroforming from a rapid prototyping mandrel. The approach involves conformal heating and cooling channels , where the oil flows into a parallel channel to the electroformed cavity (nickel or copper). Because of this the mould enables high temperature uniformity with direct heating and cooling of the electroformed shell, Uniform heating and cooling is important not only for good quality parts but also for good uniform wall thickness distribution in the rotationally moulded part. The experimental work with the manufactured prototype mould has enabled analysis of the thermal uniformity in the cavity, under different temperatures. Copyright © 2008 by ASME.

Algoritmos de planificación en redes de paquetes

En este artículo se presentan los mecanismos y procesos necesarios que realizan los enrutadores para ofrecer calidad de servicio en redes de paquetes y se hace especial énfasis en el estudio del estado del arte en lo referente a los algoritmos de planificación utilizados en este tipo de redes.

Case-Based Reasoning as a Heuristic Selector in a Hyper-Heuristic for Course Timetabling Problems

This paper studies Knowledge Discovery (KD) using Tabu Search and Hill Climbing within Case-Based Reasoning (CBR) as a hyper-heuristic method for course timetabling problems. The aim of the hyper-heuristic is to choose the best heuristic(s) for given timetabling problems according to the knowledge stored in the case base. KD in CBR is a 2-stage iterative process on both case representation and the case base. Experimental results are analysed and related research issues for future work are discussed.

Heat transfer performance investigation of nanofluids flow in pipe

Different types of base fluids, such as water, engine oil, kerosene, ethanol, methanol, ethylene glycol etc. are usually used to increase the heat transfer performance in many engineering applications. But these conventional heat transfer fluids have often several limitations. One of those major limitations is that the thermal conductivity of each of these base fluids is very low and this results a lower heat transfer rate in thermal engineering systems. Such limitation also affects the performance of different equipments used in different heat transfer process industries. To overcome such an important drawback, researchers over the years have considered a new generation heat transfer fluid, simply known as nanofluid with higher thermal conductivity. This new generation heat transfer fluid is a mixture of nanometre-size particles and different base fluids. Different researchers suggest that adding spherical or cylindrical shape of uniform/non-uniform nanoparticles into a base fluid can remarkably increase the thermal conductivity of nanofluid. Such augmentation of thermal conductivity could play a more significant role in enhancing the heat transfer rate than that of the base fluid. Nanoparticles diameters used in nanofluid are usually considered to be less than or equal to 100 nm and the nanoparticles concentration usually varies from 5% to 10%. Different researchers mentioned that the smaller nanoparticles concentration with size diameter of 100 nm could enhance the heat transfer rate more significantly compared to that of base fluids. But it is not obvious what effect it will have on the heat transfer performance when nanofluids contain small size nanoparticles of less than 100 nm with different concentrations. Besides, the effect of static and moving nanoparticles on the heat transfer of nanofluid is not known too. The idea of moving nanoparticles brings the effect of Brownian motion of nanoparticles on the heat transfer. The aim of this work is, therefore, to investigate the heat transfer performance of nanofluid using a combination of smaller size of nanoparticles with different concentrations considering the Brownian motion of nanoparticles. A horizontal pipe has been considered as a physical system within which the above mentioned nanofluid performances are investigated under transition to turbulent flow conditions. Three different types of numerical models, such as single phase model, Eulerian-Eulerian multi-phase mixture model and Eulerian-Lagrangian discrete phase model have been used while investigating the performance of nanofluids. The most commonly used model is single phase model which is based on the assumption that nanofluids behave like a conventional fluid. The other two models are used when the interaction between solid and fluid particles is considered. However, two different phases, such as fluid and solid phases is also considered in the Eulerian-Eulerian multi-phase mixture model. Thus, these phases create a fluid-solid mixture. But, two phases in the Eulerian-Lagrangian discrete phase model are independent. One of them is a solid phase and the other one is a fluid phase. In addition, RANS (Reynolds Average Navier Stokes) based Standard κ-ω and SST κ-ω transitional models have been used for the simulation of transitional flow. While the RANS based Standard κ-ϵ, Realizable κ-ϵ and RNG κ-ϵ turbulent models are used for the simulation of turbulent flow. Hydrodynamic as well as temperature behaviour of transition to turbulent flows of nanofluids through the horizontal pipe is studied under a uniform heat flux boundary condition applied to the wall with temperature dependent thermo-physical properties for both water and nanofluids. Numerical results characterising the performances of velocity and temperature fields are presented in terms of velocity and temperature contours, turbulent kinetic energy contours, surface temperature, local and average Nusselt numbers, Darcy friction factor, thermal performance factor and total entropy generation. New correlations are also proposed for the calculation of average Nusselt number for both the single and multi-phase models. Result reveals that the combination of small size of nanoparticles and higher nanoparticles concentrations with the Brownian motion of nanoparticles shows higher heat transfer enhancement and thermal performance factor than those of water. Literature suggests that the use of nanofluids flow in an inclined pipe at transition to turbulent regimes has been ignored despite its significance in real-life applications. Therefore, a particular investigation has been carried out in this thesis with a view to understand the heat transfer behaviour and performance of an inclined pipe under transition flow condition. It is found that the heat transfer rate decreases with the increase of a pipe inclination angle. Also, a higher heat transfer rate is found for a horizontal pipe under forced convection than that of an inclined pipe under mixed convection.

Diseño, desarrollo e implementación de un sistema de información que ayude al cumplimiento de la ley de transparencia y acceso a la información pública

139 p.

Les facteurs affectant les taux de réussite des cours d’anglais et de sciences humaines des étudiants dans les programmes de formation technique

A large percentage of Vanier College's technology students do not attain their College degrees within the scheduled three years of their program. A closer investigation of the problem revealed that in many of these cases these students had completed all of their program professional courses but they had not completed all of the required English and/or Humanities courses. Fortunately, most of these students do extend their stay at the college for the one or more semesters required for graduation, although some choose to go on into the workforce without returning to complete the missing English and/or Humanities and without their College Degrees. The purpose of this research was to discover if there was any significant measure of association between a student's family linguistic background, family cultural background, high school average, and/or College English Placement Test results and his or her likelihood of succeeding in his or her English and/or Humanities courses within the scheduled three years of the program. Because of both demographic differences between 'hard' and 'soft' technologies, including student population, more specifically gender ratios and student average ages in specific programs; and program differences, including program writing requirements and types of practical skill activities required; in order to have a more uniform sample, the research was limited to the hard technologies where students work hands-on with hardware and/or computers and tend to have overall low research and writing requirements. Based on a review of current literature and observations made in one of the hard technology programs at Vanier College, eight research questions were developed. These questions were designed to examine different aspects of success in the English and Humanities courses such as failure and completion rates and the number of courses remaining after the end of the fifth semester and as well examine how the students assessed their ability to communicate in English. The eight research questions were broken down into a total of 54 hypotheses. The high number of hypotheses was required to address a total of seven independent variables: primary home language, high school language of instruction, student's place of birth (Canada, Not-Canada), student's parents' place of birth (Both-born-in-Canada, Not-both-born-in-Canada), high school averages and English placement level (as a result of the College English Entry Test); and eleven dependent variables: number of English completed, number of English failed, whether all English were completed by the end of the 5th semester (yes, no), number of Humanities courses completed, number of Humanities courses failed, whether all the Humanities courses were completed by the end of the 5th semester (yes, no), the total number of English and Humanities courses left, and the students' assessments of their ability to speak, read and write in English. The data required to address the hypotheses were collected from two sources, from the students themselves and from the College. Fifth and sixth semester students from Building Engineering Systems, Computer and Digital Systems, Computer Science and Industrial Electronics Technology Programs were surveyed to collect personal information including family cultural and linguistic history and current language usages, high school language of instruction, perceived fluency in speaking, reading and writing in English and perceived difficulty in completing English and Humanities courses. The College was able to provide current academic information on each of the students, including copies of college program planners and transcripts, and high school transcripts for students who attended a high school in Quebec. Quantitative analyses were done on the data using the SPSS statistical analysis program. Of the fifty-four hypotheses analysed, in fourteen cases the results supported the research hypotheses, in the forty other cases the null hypotheses had to be accepted. One of the findings was that there was a strong significant association between a student's primary home language and place of birth and his or her perception of his or her ability to communicate in English (speak, read, and write) signifying that both students whose primary home language was not English and students who were not born in Canada, considered themselves, on average, to be weaker in these skills than did students whose primary home language was English. Although this finding was noteworthy, the two most significant findings were the association found between a student's English entry placement level and the number of English courses failed and the association between the parents' place of birth and the student's likelihood of succeeding in both his or her English and Humanities courses. According to the research results, the mean number of English courses failed, on average, by students placed in the lowest entry level of College English was significantly different from the number of English courses failed by students placed in any of the other entry level English courses. In this sample students who were placed in the lowest entry level of College English failed, on average, at least three times as many English courses as those placed in any of the other English entry level courses. These results are significant enough that they will be brought to the attention of the appropriate College administration. The results of this research also appeared to indicate that the most significant determining factor in a student's likelihood of completing his or her English and Humanities courses is his or her parents' place of birth (both-born-in-Canada or not-both-born-in-Canada). Students who had at least one parent who was not born in Canada, would, on average, fail a significantly higher number of English courses, be significantly more likely to still have at least one English course left to complete by the end of the 5th semester, fail a significantly higher number of Humanities courses, be significantly more likely to still have at least one Humanities course to complete by the end of the 5th semester and have significantly more combined English and Humanities courses to complete at the end of their 5th semester than students with both parents born in Canada. This strong association between students' parents' place of birth and their likelihood of succeeding in their English and Humanities courses within the three years of their program appears to indicate that acculturation may be a more significant factor than either language or high school averages, for which no significant association was found for any of the English and Humanities related dependent variables. Although the sample size for this research was only 60 students and more research needs to be conducted in this area, to see if these results are supported with other groups within the College, these results are still significant. If the College can identify, at admission, the students who will be more likely to have difficulty in completing their English and Humanities courses, the College will now have the opportunity to intercede during or before the first semester, and offer these students the support they require in order to increase their chances of success in their education, whether it be classes or courses designed to meet their specific needs, special mentoring, tutoring or other forms of support. With the necessary support, the identified students will have a greater opportunity of successfully completing their programs within the scheduled three years, while at the same time the College will have improved its capacity to meeting the needs of its students.

Retos en la implementación de las normas internacionales al interior de los estados. estudio de caso: la región del Mekong y el protocolo de Palermo contra la trata de personas. (2007-2014)

El presente estudio de caso tiene como principal objetivo el de analizar la manera como las características sociopolíticas de los Estados del Mekong, específicamente en el caso de Camboya y Myanmar, dificultan la implementación de las normas enunciadas en el Protocolo de las Naciones Unidas para Prevenir, Reprimir y Sancionar la Trata de Personas, Especialmente Mujeres y Niños, también conocido como el Protocolo de Palermo. En este sentido, se parte de las características principales del Protocolo y de la manera como el tráfico de personas se presenta en el Mekong para posteriormente analizar la forma como la corrupción, la impunidad y la desigualdad de género representan retos sociopolíticos que obstruyen la implementación de los mandatos internacionales enmarcados en este instrumento

Reverse engineering in many-body quantum physics: Correspondence between many-body systems and effective single-particle equations

The mapping, exact or approximate, of a many-body problem onto an effective single-body problem is one of the most widely used conceptual and computational tools of physics. Here, we propose and investigate the inverse map of effective approximate single-particle equations onto the corresponding many-particle system. This approach allows us to understand which interacting system a given single-particle approximation is actually describing, and how far this is from the original physical many-body system. We illustrate the resulting reverse engineering process by means of the Kohn-Sham equations of density-functional theory. In this application, our procedure sheds light on the nonlocality of the density-potential mapping of density-functional theory, and on the self-interaction error inherent in approximate density functionals.

A systems biology framework for pathway level culture media engineering: pplication to Pichia pastoris cultures

Dissertação para obtenção do Grau de Doutor em Engenharia Química e Bioquímica

Functional characterization and directed engineering of redox proteins for a rational improvement of Bioelectrochemical systems

In recent years, new methods of clean and environmentally friendly energy production have been the focus of intense research efforts. Microbial fuel cells (MFCs) are devices that utilize naturally occurring microorganisms that feed on organic matter, like waste water, while producing electrical energy. The natural habitats of bacteria thriving in microbial fuel cells are usually marine and freshwater sediments. These microorganisms are called dissimilatory metal reducing bacteria (DMRB), but in addition to metals like iron and manganese, they can use organic compounds like DMSO or TMAO, radionuclides and electrodes as terminal electron acceptors in their metabolic pathways.(...)

Development of advanced cell/tissue culture systems, based on enhanced polymeric scaffolds and sophisticated bioreactors, for tissue engineering applications

Programa Doutoral em Engenharia Biomédica

Human fetal bone cells in delivery systems for bone engineering.

The aim of this study was to culture human fetal bone cells (dedicated cell banks of fetal bone derived from 14 week gestation femurs) within both hyaluronic acid gel and collagen foam, to compare the biocompatibility of both matrices as potential delivery systems for bone engineering and particularly for oral application. Fetal bone cell banks were prepared from one organ donation and cells were cultured for up to 4 weeks within hyaluronic acid (Mesolis(®)) and collagen foams (TissueFleece(®)). Cell survival and differentiation were assessed by cell proliferation assays and histology of frozen sections stained with Giemsa, von Kossa and ALP at 1, 2 and 4 weeks of culture. Within both materials, fetal bone cells could proliferate in three-dimensional structure at ∼70% capacity compared to monolayer culture. In addition, these cells were positive for ALP and von Kossa staining, indicating cellular differentiation and matrix production. Collagen foam provides a better structure for fetal bone cell delivery if cavity filling is necessary and hydrogels would permit an injectable technique for difficult to treat areas. In all, there was high biocompatibility, cellular differentiation and matrix deposition seen in both matrices by fetal bone cells, allowing for easy cell delivery for bone stimulation in vivo. Copyright © 2011 John Wiley & Sons, Ltd.

Competitive flexibility in systems supplier companies in mechanical engineering industry

Systems suppliers are focal actors in mechanical engineering supply chains, in between general contractors and component suppliers. This research concentrates on the systems suppliers’ competitive flexibility, as a competitive advantage that the systems supplier gains from independence from the competitive forces of the market. The aim is to study the roles that power, dependence relations, social capital, and interorganizational learning have on the competitive flexibility. Research on this particular theme is scarce thus far. The research method applied here is the inductive multiple case study. Interviews from four case companies were used as main source of the qualitative data. The literature review presents previous literature on subcontracting, supply chain flexibility, supply chain relationships, social capital and interorganizational learning. The result of this study are seven propositions and consequently a model on the effects that the dominance of sales of few customers, power of competitors, significance of the manufactured system in the end product, professionalism in procurement and the significance of brand products in the business have on the competitive flexibility. These relationships are moderated by either social capital or interorganizational learning. The main results obtained from this study revolve around social capital and interorganizational learning, which have beneficial effects on systems suppliers’ competitive flexibility, by moderating the effects of other constructs of the model. Further research on this topic should include quantitative research to provide the extent to which the results can be reliably generalized. Also each construct of the model gives possible focus for more thorough research.