BCIT Citations Collection | BCIT Institutional Repository

BCIT Citations Collection

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Collection of published works from BCIT researchers, faculty, and instructors.

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The effects of global climate change on carbonation induced corrosion of reinforced concrete structures
There is nearly unanimous consensus amongst scientists that increasing greenhouse gas emissions, including CO2 generated by human activity, are affecting the Earth‘s climate. Climate change has the potential to overwhelm existing capacities, as well as durability of concrete infrastructure. Carbonation of concrete occurs due to a reaction between atmospheric CO2 and the hydrated phases of concrete, leading to a drop in its pH and the depassivation of embedded rebar. Therefore, increases in carbonation rates of reinforced concrete structures are expected as a result of increased temperatures and CO2 concentrations, with the enhanced risk of carbonation induced corrosion likely affecting the longevity of our concrete infrastructure. This thesis considered the potential consequences of global climate change on our concrete infrastructure, with the objective being to determine if there is an increased risk of deterioration due to carbonation induced corrosion. A unique numerical model was developed to determine carbonation rates in structures, and verified through experimental tests. The model was applied to a numbers of cities in locations throughout the world to determine where structures were most vulnerable. Additionally, a number of other laboratory experiments were carried out to supplement the numerical model and provide insights as to how carbonation progress can be monitored within a structure. Using the model developed, and inputting forecasts for increases in future atmospheric CO2 concentrations and weather conditions, it was shown that for medium quality, non-pozzolonic concrete in geographic areas where carbonation induced corrosion is a concern, global climate change will affect its progress in our concrete infrastructure. We will see much higher ultimate carbonation depths in the long term. The use of non-destructive testing (NDT) methods, and structural health monitoring (SHM) techniques could be invaluable in monitoring the progress of carbonation in a structure, but the data generated by the methods and techniques used must be analyzed carefully before making any conclusions. For the NDT methods and carbonation pH sensors which were evaluated in this study, it was found that ambient test conditions had a major impact on results., Thesis, Published.
The effects of structural cracking on carbonation progress in reinforced concrete
Proceedings of 3rd International Conference on the Durability of Concrete Structures, 17-19 September 2012, Queen’s University Belfast. There is nearly unanimous consensus among scientists that increasing greenhouse gas emissions, including CO2 generated by human activity, are affecting the Earth’s climate. One essential area which will be affected is the durability of concrete infrastructure. Past research indicates that climate change will exacerbate the rate of carbonation of reinforced concrete structures, potentially leading to premature corrosion of embedded rebar. Cracking of the covering concrete could further increase carbonation rates, but the extent of the increase is unknown. The purpose of this study is to investigate the carbonation of cracked concrete under accelerated test conditions, and to numerically model the movement of the carbonation front in cracked concrete using the concept of effective diffusivity. It was found that the presence of a deep structural crack in a concrete specimen greatly increases the rate of carbonation, possibly leading to premature, localized corrosion within the specimen. The effect of cracks is likely to be much greater than the effect of increased temperatures and increased atmospheric CO2 concentrations. As a result, emphasis must be placed on designing durable infrastructure and following proper maintenance practices so that cracks are less likely to form, thereby extending the longevity of the structure in question., Conference paper, Published.
Emotional design
In my teaching and software development practice, I realized that most applications with human-computer interaction do not respond to usersâ emotional needs. The dualism of reason and emotion as two fairly opposite entities that dominated Western philosophy was also reflected in software design. Computing was originally intended to provide applications for military and industrial activities and was primarily associated with cognition and rationality. Today, more and more computer applications interact with users in very complex and sophisticated ways. In human-computer interaction, attention is given to issues of usability and user modeling, but techniques to emotionally engage users or respond to their emotional needs have not been fully developed, even as specialists like Klein, Norman and Picard argued that machines that recognize and express emotions respond better and more appropriately to user interaction (Picard, 1997; Picard & Klein, 2002; Norman, 2004). This study investigated emotion from designersâ perspectives and tentatively concludes that there is little awareness and involvement in emotional design in the IT community. By contrast, participants in this study (36 IT specialists from various fields) strongly supported the idea of emotional design and confirmed the need for methodologies and theoretical models to research emotional design. Based on a review of theory, surveys and interviews, I identified a set of themes for heuristics of emotional design and recommended future research directions. Attention was given to consequences; participants in this study raised issues of manipulation, ethical responsibilities of designers, and the need for regulations, and recommended that emotional design should carry standard ethical guidelines for games and any other applications. The research design utilized a mixed QUAN-qual methodological model proposed by Creswell (2003) and Gay, Mills, and Airasian (2006), which was modified to equally emphasize both quantitative and qualitative stages. An instrument in the form of a questionnaire was designed, tested and piloted in this study and will be improved and used in future research., Published., Peer reviewed, Thesis/Dissertation
Emotional design
Proceedings from the First Biannual Conference on Technological Learning and Thinking: Culture, Design, Sustainability, Human Ingenuity held in Vancouver, BC, Canada, 2010., Not peer reviewed, Conference paper
Endogenous TrkB ligands suppress functional mechanosensory plasticity in the deafferented spinal cord
Dorsal root injury (DRI) disrupts the flow of sensory information to the spinal cord. Although primary afferents do not regenerate to their original targets, spontaneous recovery can, by unknown mechanisms, occur after DRI. Here, we show that brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), but not nerve growth factor or neurotrophin-4, are upregulated in the spinal gray matter after DRI. Because endognous BDNF and NT-3 have well established roles in synaptic and axonal plasticity, we hypothesized that they contributed to spontaneous recovery after DRI. We first developed a model of DRI-induced mechanosensory dysfunction: rat C7/8 DRI produced a deficit in low-threshold cutaneous mechanosensation that spontaneously improved within 10 d but did not recover completely. To determine the effects of endogenous BDNF and NT-3, we administered TrkB-Fc or TrkC-Fc fusion proteins throughout the recovery period. To our surprise, TrkB-Fc stimulated complete recovery of mechanosensation by 6 d after DRI. It also stimulated mechanosensory axon sprouting but prevented deafferentation-induced serotonergic sprouting. TrkC-Fc had no effect on low-threshold mechanosensory behavior or axonal plasticity. There was no mechanosensory improvement with single-bolus TrkB-Fc infusions at 10 d after DRI (despite significantly reducing rhizotomy-induced cold pain), indicating that neuromodulatory effects of BDNF did not underlie mechanosensory recovery. Continuous infusion of the pan-neurotrophin antagonist K252a also stimulated behavioral and anatomical plasticity, indicating that these effects of TrkB-Fc treatment occurred independent of signaling by other neurotrophins. These results illustrate a novel, plasticity-suppressing effect of endogenous TrkB ligands on mechanosensation and mechanosensory primary afferent axons after spinal deafferentation., Peer-reviewed article, Published. Received Oct. 2, 2006; revised March 26, 2007; accepted April 20, 2007.
Energy rating of polyurethane spray foamed walls
Proceedings of 4th International Building Physics Conference: 15 June 2009, Istanbul, Turkey. This is the first of a series of papers to present the results of this major project. In this paper, an overview of the project, its objectives and the theoretical approach to determine the WER are presented. A description of air leakage and R-value test procedures, wall samples construction and the experimental results of two walls and a sample of the analytical results of the same two walls will also be presented. Future papers will summa-rise the experimental and analytical results of the remaining walls, along with the results of the computer modeling of the air leakage and thermal performance of all the walls tested in this project., Conference paper, Published. A version of this document is published in: 4th International Building Physics Conference, Istanbul, Turkey, June 15-18, 2009, pp. 1-8.
Enhancing student engagement and learning effectiveness through multi-role contributions and collaborative exams
This project proposes teaching-learning coupling as students take different roles during the course, from being learners, teachers, and proponents; finally, students take exams in a collaborative manner – initially, their exam is done individually followed by a team consultation period for the exam completion., Not peer reviewed, report
Environmental regulation, asymmetric information, and moral hazard
This paper presents a model of environmental regulation in the presence of measurement costs and asymmetric information. Environmental regulation can be viewed as a form of agency problem where the polluting firms may have better information about the true level of their abatement activities than the regulator. If certain aspects of environmental quality are costly to measure, regulators may resort to proxies to infer information about environmental quality. This may allow firms to circumvent the regulatory constraints by maximizing along those margins that are costly to measure. This problem is especially acute when a single firm produces multiple pollutants., Essay, Published.
Environmentally friendly transport
Article, Published.
Evaluating the use of potentially hazardous secondary aggregates in concrete based on life-cycle effects on water pollution
Proceedings from the 28th International Conference on Solid Waste Technology and Management, Philadelphia, PA U.S.A, March 10-13, 2013., Peer reviewed, Conference proceeding
Evaluation of the thermal performance of innovative pre-fabricated wall systems through field testing
Proceedings of the 3rd Building Enclosure Science & Technology (BEST3) Conference, Atlanta, USA, April 2-4, 2012. The thermal performance of two innovative pre-fabricated wood-frame wall systems was evaluated in comparison with a conventional 2x6 wood frame wall through one year’s field monitoring on BCIT’s Building Envelope Test Facility. Prefabricated wall system I has 4” Expanded Polystyrene (EPS) infill in the stud cavity with 1” additional EPS added on the interior side of 2x4 wood stud. Prefabricated wall system II has 4” EPS infill in the stud cavity only. The conventional 2x6 wood frame wall has 5-1/2” fiberglass insulation infill in the stud cavity. The effective thermal efficiency of these test walls is evaluated in terms of heat flux, effective in-situ R-values, and temperature distribution. The heat flux measurements show that, in comparison with the conventional 2x6 wood frame wall, prefabricated wall system I with 4” EPS infill in the stud cavity has 5.1% less heat loss and 16% less heat gain and the prefabricated wall system II with 1" extra EPS has 22.9% less heat loss and 37.5% less heat gain. The improvement of thermal efficiency in the prefabricated wall systems is mainly attributed to the significant improvement over the stud areas. Estimated effective R-values over the winter months from December 2008 to March 2009 show that the R-value over the stud area in prefabricated wall system I is improved by 32.7% while the R-value over the cavity area is reduced by 8.7%, resulting in a net improvement of effective wall R-value by 2.9%; and the R-value over the stud area in prefabricated wall system II is improved by 112.3% with only a 2.6% improvement in the R-value over the cavity area, resulting in a net improvement of effective wall R-value by 26.5%. Temperature measurements show that the interior surface temperatures over the stud area in the conventional wall fluctuate much more and are higher during the summer months and lower during the winter months compared to the prefabricated systems, due to the thermal bridging effect of the stud., Conference paper, Published.
Evidence-based solution to information sharing between criminal justice agencies
This paper originates from a project done for and with the assistance of the Operations Strategy Branch, E Division, Royal Canadian Mounted Police. The aim of this study was to test a technological solution to two traditional limitations of information sharing between criminal justice agencies: data quality and privacy concerns. Entity Analytics Software (EAS) was tested in two studies with North American criminal justice agencies. In the first test, duplicated cases held in a police record system were successfully identified (4.0%) to a greater extent than the traditionally used software program (1.5%). This resulted in a difference of 11,954 cases that otherwise would not have been identified as duplications. In the second test, entity information held separately by police and border officials was shared anonymously between these two organizations. This resulted in 1,827 alerts regarding entities that appeared in both systems; traditionally, this information could not have been shared, given privacy concerns, and neither criminal justice agency would be aware of the relevant information held by the other. Data duplication resulted in an additional 1,041 alerts, which highlights the need to use technological solutions to improve data quality prior to and during information sharing. While only one potential technological solution (EAS) was tested and organizations must consider the potential expense associated with implementing such technology, the implications resulting from both studies for improved awareness and greater efficiency support and facilitate information sharing between criminal justice organizations., Research paper, Published.
Evolution in silico of genes with multiple regulatory modules on the example of the Drosophila segmentation gene hunchback
Proceedings of 2012 IEEE Symposium on Computational Intelligence in Bioinformatics and Computational Biology (CIBCB) on 9-12 May 2012 in San Diego, CA, USA. We use in silico evolution to study the generation of gene regulatory structures. A particular area of interest in evolutionary development (evo-devo) is the correspondence between gene regulatory sequences on the DNA (cis-regulatory modules, CRMs) and the spatial expression of the genes. We use computation to investigate the incorporation of new CRMs into the genome. Simulations allow us to characterize different cases of CRM to spatial pattern correspondence. Many of these cases are seen in biological examples; our simulations indicate relative advantages of the different scenarios. We find that, in the absence of specific constraints on the CRM-pattern correspondence, CRMs controlling multiple spatial domains tend to evolve very quickly. Genes constrained to a one-to-one CRM-pattern domain correspondence evolve more slowly. Of these, systems in which pattern domains appear in a particular order in evolution, as in insect segmentation mechanisms, take the longest time in in silico evolutionary searches. For biological cases of this type, it is likely that other selective advantages outweigh the time costs., Conference paper, Published.
Experimental determination of intrinsic drosophila embryo coordinates by evolutionary computation
Proceedings of 8th IAPR International Conference, PRIB 2013, Nice, France, June 17-20, 2013. Early fruit fly embryo development begins with the formation of a chemical blueprint that guides cellular movements and the development of organs and tissues. This blueprint sets the intrinsic spatial coordinates of the embryo. The coordinates are curvilinear from the start, becoming more curvilinear as cells start coherent movements several hours into development. This dynamic aspect of the curvature is an important characteristic of early embryogenesis: characterizing it is crucial for quantitative analysis and dynamic modeling of development. This presents a number of methodological problems for the elastic deformation of 3D and 4D data from confocal microscopy, to standardize images and follow temporal changes. The parameter searches for these deformations present hard optimization problems. Here we describe our evolutionary computation approaches to these problems. We outline some of the immediate applications of these techniques to crucial problems in Drosophila developmental biology., Conference paper, Published.
Experimental investigation of moisture transfer between concrete foundation and sill plate
Precipitation is one of the most common moisture sources on which building designers focus. Water comes from both top down and bottom up. Although foundations are sometimes constructed out of pressure-treated lumber, generally they are constructed from poured concrete. In a wet climate zone, the foundation of a house is often under continuous contact with moisture, which is mainly caused by rundown rainwater, wet soil, a high water table, or a combination of all these factors. This causes rot growth and decay of the wood-frame structure as it sits constantly on the damp foundation concrete. In this research, moisture transfer between concrete and wood is investigated under three different scenarios: a case with direct wood and concrete contact and two cases with different moisture barriers between the two materials. The moisture barrier materials considered in this study are the damp-proofing layer and sill plate gasket. The moisture transfer processes in these three cases are investigated in a field experimental setting using a customized experimental setup for 1 year. The experimental data suggest that using damp proofing and a sill gasket helps restrict moisture transfer., Peer reviewed article, Published. Received: May 29, 2015; Accepted: December 09, 2015; Published online: February 24, 2016.
Experimental investigation of the sound absorption characteristics of vegetated roofs
An experimental investigation of the sound absorption characteristics of vegetated roof substrates and plots has been completed. First, an impedance tube was used to measure the normal-incidence absorption coefficients of substrates and their constituents. Substrates provided significant sound absorption, with coefficients varying from 0.03 at 250 Hz to 0.89 at 2000 Hz. Absorption increased with the percentage of organic matter and decreased with moisture content and compaction. A multi-variable regression model was developed for predicting the absorption of substrates. Secondly, the sound absorption of vegetated roof plots was investigated using the spherical-decoupling method. An optimal method, validated in an anechoic chamber, was used to determine the diffuse-field absorption coefficients of unplanted and planted rooftop test plots. Sound absorption increased with increased substrate depth (without vegetation) and decreased with the addition of vegetation and plant establishment. The mean noise reduction coefficient of established vegetated roof plots, with distinctly different plant communities in substrate depths of 50–200 mm, ranged from 0.20 to 0.63 when evaluated over a two-year period. The results confirm that the sound absorption of vegetated roofs is a function of substrate depth, plant community establishment, and moisture content in the plants and substrate., Peer-reviewed article, Published. Received 4 March 2015, Revised 22 April 2015, Accepted 23 April 2015, Available online 1 May 2015.

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