BCIT Citations Collection
Collection of published works from BCIT researchers, faculty, and instructors.
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- Hygrothermal performance of exterior wall systems using an innovative vapour retarder in Canadian climate
- Proceeding of the 4th International Building Physics Conference: 15 June 2009, Istanbul, Turkey. This paper provides highlights of the research work carried out at the National Research Council Canada, Institute for Research in Construction on assessing the hygrothermal performance of wall systems that included this innovative vapour retarder (Note: Vapour Barrier in Canadian terminology is equivalent to Vapor retarder in US terminology). The performance of walls was assessed when subjected to eastern coastal climate conditions of Halifax, one of the four Canadian climatic locations used in this study. A wood-framed stucco clad wall was the reference assembly. Results from different cases based on the variation of vapour control strategies and their effect on the hygrothermal performance of the wall systems are analysed. The results for the Halifax climate location indicate that the installation of a humidity controlled, innovative vapour retarder is a recommendable solution for the envelope design of residential buildings of these locations with moderate or high water vapour permeance of the interior paint. In this study, the advanced hygrothermal tool, hygIRC, was used to perform the hygrothermal performance analysis of the wall systems., Peer reviewed article, Published. A version of this document is published in: 4th International Building Physics Conference, Istanbul, Turkey, June 15-18, 2009, pp. 1-8.
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- Hygrothermal performance of ventilated attic in marine climate under different ceiling air tightness
- 14th International Conference on Indoor Air Quality and Climate (Indoor Air 2016), July 3-8, 2016, Ghent, Belgium. An indoor to attic air leakage and vice-versa significantly affect indoor air, thermal comfort and the hygrothermal performance in both living space and unconditioned space. In cold and marine climates an air leakage from living space to an attic brings a relatively high relative humidity to the attic space. This effect is primarily responsible for condensation in attic structural parts such as roof sheathings. In this paper, the hygrothermal performance of a ventilated attic in wet costal climates under different ceiling air leakage is studied. A benchmarked whole building Heat-Air-Moisture model named HAMFit is used to study hygrothermal performance of ventilated attics in marine climates. The attic is modelled as 2-dimensional geometry with coupled heat transfer, moisture transport and a turbulence Computational Fluid Dynamics through attic space and porous structural parts of the attic. A vent ratio of 1/300 and three types normalized leakage area (tight, normal and leaky) are used to analyse how the moisture transport behaves in ventilated space. A winter weather data of city of Vancouver, BC is used to represent a wet marine climate. Our findings show specific locations in the attic structure are more exposed to moisture related problems and the air circulation and temperature distribution due to ventilation under multiple ceiling air leakage scenarios are presented. Hygrothermal performance of ventilated attic in marine climate under different ceiling air tightness., Conference paper, Published.
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- Hygrothermal properties of exterior claddings, sheathing boards, membranes and insulation materials for building envelope design
- Proceedings of Thermal Performance of the Exterior Envelopes of Whole Buildings X International Conference: 02 December 2007, Clearwater, Florida. Testing was conducted to determine those construction material properties that affect the movement of heat, air, and moisture in building envelopes. The paper reports the density, thermal conductivity, equilibrium moisture content, water vapor permeability, water absorption coefficient, liquid diffusivity, and air permeability of twenty-three building materials commonly used in North American including: exterior claddings, exterior sheathing boards, membranes and insulations. The paper also discusses the experimental and analytical procedures used to determine these properties., Conference paper, Published. A version of this document is published in: Proceedings of Thermal Performance of the Exterior Envelopes of Whole Buildings X, Clearwater, Florida, Dec. 2-7, 2007, pp. 1-16.
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- Identification of quantitative trait loci controlling fibre length and lignin content in Arabidopsis thaliana stems
- Fibre properties and the biochemical composition of cell walls are important traits in many applications. For example, the lengths of fibres define the strength and quality of paper, and lignin content is a critical parameter for the use of biomass in biofuel production. Identifying genes controlling these traits is comparatively difficult in woody species, because of long generation times and limited amenability to high-resolution genetic mapping. To address this problem, this study mapped quantitative trait loci (QTLs) defining fibre length and lignin content in the Arabidopsis recombinant inbred line population Col-4×Ler-0. Adapting high-throughput phenotyping techniques for both traits for measurements in Arabidopsis inflorescence stems identified significant QTLs for fibre length on chromosomes 2 and 5, as well as one significant QTL affecting lignin content on chromosome 2. For fibre length, total variation within the population was 208% higher than between parental lines and the identified QTLs explained 50.58% of the observed variation. For lignin content, the values were 261 and 26.51%, respectively. Bioinformatics analysis of the associated intervals identified a number of candidate genes for fibre length and lignin content. This study demonstrates that molecular mapping of QTLs pertaining to wood and fibre properties is possible in Arabidopsis, which substantially broadens the use of Arabidopsis as a model species for the functional characterization of plant genes., Peer-reviewed article, Published. Received 3 April 2012; Revised 11 October 2012; Accepted 15 October 2012.
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- Impact of EV penetration on Volt–VAR Optimization of distribution networks using real-time co-simulation monitoring platform
- This paper aims to investigate the impact of different Electric Vehicle (EV) penetration on quasi real-time Volt–VAR Optimization (VVO) of smart distribution networks. Recent VVO solutions enable capturing data from Advanced Metering Infrastructure (AMI) in quasi real-time to minimize distribution networks loss costs and perform Conservation Voltage Reduction (CVR) to save energy. The emergence of EVs throughout distribution feeder increases grid complexity and uncertainty levels that could affect AMI-based VVO objectives. Hence, this paper primarily introduces an AMI-based VVO engine, able to minimize grid loss and Volt–VAR control assets operating costs while maximizing CVR benefit. It then presents a real-time co-simulation platform comprised of the VVO engine, grid model in a real-time simulator and monitoring platform, communicating with each other through DNP.3 protocol, to test the precision and performance of AMI-based VVO in presence of different EV penetration levels. Accordingly, 33-node distribution feeder is studied through different EV penetration scenarios. The results show significant changes in AMI-based VVO performance especially in CVR sub-part of VVO according to EV model and type. Thus, this study could lead near future VVO solutions to gain higher levels of accuracy and efficiency considering smart microgrid components such as EV in their models., Article, Published. Received 27 November 2015, Revised 8 January 2016, Accepted 22 January 2016, Available online 16 February 2016.
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- Impact of V2G on real-time adaptive Volt/VAr optimization of distribution networks
- Proceeding of IEEE ElectricalPower and Energy Conference (EPEC 2013), Aug. 2013, Halifax, Canada. Deployment of Smartgrid downstream features such as Smart Metering, pervasive control and Distributed Management Systems has brought great opportunities for distribution network planners to optimize the network in more precise methods. Moreover, the advent of Electric Vehicles (EVs) has brought more opportunities for grid optimization. Recent studies stipulate that EVs are able to inject reactive power into the grid by changing their inverter's operating mode. This paper primarily discusses a real-time adaptive Volt/VAr Optimization (VVO) engine, designed to minimize system apparent power losses, optimize voltage profiles, and reduce the operating costs of Switched Capacitor Banks of the grid. The paper goes on to study the impact of EVs on the distribution network VVO, taking into account different EV charging and penetration levels and checks the validity of the proposed algorithm by employing revised IEEE-37 Node Test Feeder in presence of various load types as a case study., Conference paper, Published.
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- Impact of electrical intertie capacity on carbon policy effectiveness
- This study investigates the potential cost and emissions reductions that result from an increase in electricity transmission capacity between Canada's two westernmost provinces: Alberta, a fossil fuel dominated jurisdiction, and British Columbia, a predominantly hydroelectric jurisdiction. A bottom-up model is used to find the least cost electricity generation mix in Alberta and British Columbia under different carbon policies. The long-term evolution of the electricity system is determined by minimizing net present cost of electricity generation for the time span of 2010–2060. Different levels of intertie capacity expansion are considered together with a variety of carbon tax and carbon cap scenarios. Results indicate that increased intertie capacity reduces the cost of electricity and emissions under carbon pricing policies. However, the expandable intertie does not encourage greater adoption of variable renewable generation. Instead, it is used to move low-cost energy from the United States to Alberta. The optimal intertie capacity and cost reduction of increased interconnectivity increases with more restrictive carbon policies., Peer-reviewed article, Published. Received 3 March 2016, Revised 23 September 2016, Accepted 12 October 2016, Available online 15 November 2016.
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- Improved dynamic friction models for simulation of one-dimensional and two-dimensional stick-slip motion
- In many mechanical systems, the tendency of sliding components to intermittently stick and slip leads to undesirable performance, vibration, and control behaviors. Computer simulations of mechanical systems with friction are difficult because of the strongly nonlinear behavior of the friction force near zero sliding velocity. In this paper, two improved friction models are proposed. One model is based on the force-balance method and the other model uses a spring-damper during sticking. The models are tested on hundreds of lumped mass-spring-damper systems with time-varying excitation and normal contact forces for both one-dimensional and two-dimensional stick-slip motions on a planar surface. Piece-wise continuous analytical solutions are compared with solutions using other published force-balance and spring-damper friction models. A method has been developed to set the size of the velocity window for Karnopp’s friction model. The extensive test results show that the new force-balance algorithm gives much lower sticking velocity errors compared to the original method and that the new spring-damper algorithm exhibits no spikes at the beginning of sticking. Weibull distributions of the sticking velocity errors enable maximum errors to be estimated a priori., Technical papers, Published. Received February 03, 2000; Revised August 17, 2000.
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- Improving students' engagement with large-team software development projects
- Proceedings from the 23rd Annual ACM Conference on Innovation and Technology in Computer Science Education. Computer science and technology education should provide not only a strong theoretical foundation, but also problem solving, and communication and teamwork skills to prepare the students for careers. Including projects in curricula is a norm in many disciplines. However, projects are generally individual or based on small teams (two to five members). This paper presents my approach to teaching a capstone undergraduate computer technology course at the British Columbia Institute of Technology (BCIT) in the Computer System Technology (CST) Program in which a large class of students (maximum 22), organized into small teams work together and apply Agile software development practices to design, implement, integrate and test a large project. This model provides students with unique learning opportunities and experiences, as well as improving their soft skills, engagement and motivation., Peer reviewed, Conference paper, Published.
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- In silico evolution of gene cooption in pattern-forming gene networks
- Gene recruitment or cooption occurs when a gene, which may be part of an existing gene regulatory network (GRN), comes under the control of a new regulatory system. Such re-arrangement of pre-existing networks is likely more common for increasing genomic complexity than the creation of new genes. Using evolutionary computations (EC), we investigate how cooption affects the evolvability, outgrowth and robustness of GRNs. We use a data-driven model of insect segmentation, for the fruit fly Drosophila, and evaluate fitness by robustness to maternal variability—a major constraint in biological development. We compare two mechanisms of gene cooption: a simpler one with gene Introduction and Withdrawal operators; and one in which GRN elements can be altered by transposon infection. Starting from a minimal 2-gene network, insufficient for fitting the Drosophila gene expression patterns, we find a general trend of coopting available genes into the GRN, in order to better fit the data. With the transposon mechanism, we find co-evolutionary oscillations between genes and their transposons. These oscillations may offer a new technique in EC for overcoming premature convergence. Finally, we comment on how a differential equations (in contrast to Boolean) approach is necessary for addressing realistic continuous variation in biochemical parameters., Peer-reviewed article, Published. Received 29 September 2012; Accepted 13 November 2012.
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- In silico evolution of the hunchback gene indicates redundancy in cis-regulatory organization and spatial gene expression
- Biological development depends on the coordinated expression of genes in time and space. Developmental genes have extensive cis-regulatory regions which control their expression. These regions are organized in a modular manner, with different modules controlling expression at different times and locations. Both how modularity evolved and what function it serves are open questions. We present a computational model for the cis-regulation of the hunchback (hb) gene in the fruit fly (Drosophila). We simulate evolution (using an evolutionary computation approach from computer science) to find the optimal cis-regulatory arrangements for fitting experimental hb expression patterns. We find that the cis-regulatory region tends to readily evolve modularity. These cis-regulatory modules (CRMs) do not tend to control single spatial domains, but show a multi-CRM/multi-domain correspondence. We find that the CRM-domain correspondence seen in Drosophila evolves with a high probability in our model, supporting the biological relevance of the approach. The partial redundancy resulting from multi-CRM control may confer some biological robustness against corruption of regulatory sequences. The technique developed on hb could readily be applied to other multi-CRM developmental genes., Peer-reviewed article, Published.
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- Increasing efficiency of enzymatic hemicellulose removal from bamboo for production of high-grade dissolving pulp
- To improve the efficiency of enzymatic hemicellulose removal from bamboo pre-hydrolysis kraft pulp, mechanical refining was conducted prior to enzyme treatment. Refining significantly improved the subsequent hemicellulose removal efficiency by xylanase treatment. Results showed that when PFI refining was followed by 3 h xylanase treatment, the xylan content of the bamboo pre-hydrolysis kraft pulp (after first stage oxygen delignification) could be decreased to 2.72% (w/w). After bleaching of enzyme treated pulp, the alpha-cellulose content was 93.4% (w/w) while the xylan content was only 2.38%. The effect of refining on fibre properties was investigated in terms of freeness, water retention value, fibre length and fibrillation characteristics. The brightness, reactivity and viscosity were also determined to characterize the quality of final pulp. Results demonstrated the feasibility of combining refining and xylanase treatment to produce high quality bamboo dissolving pulp., Peer-reviewed article, Published. Received 1 September 2016; Revised 9 October 2016; Accepted 12 October 2016; Available online 24 October 2016.