BCIT Thesis and other Required Graduate Degree Works | BCIT Institutional Repository

BCIT Thesis and other Required Graduate Degree Works

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The absorption and scattering characteristics of interior living walls
Installation of interior living walls is increasing rapidly due to their beauty, biophilic design and their potential contribution to indoor environmental quality. However, there is little understanding of the specific effect they have on the acoustics of a room. To advance the state of practice, this interdisciplinary study explores the acoustical characteristics of interior living walls to determine how they can be used to positively benefit room acoustic by reducing excess noise and reverberation. Specifically, the objective of the research is to measure the acoustical characteristics of the interior living wall in order to determine their absorption coefficient, scattering coefficient, and the parameters that most significantly impact these coefficients. First, a series of measurements are carried out in a reverberation chamber to examine random-incidence absorption by considering parameters such as carrier type, moisture content, vegetation type, and substrate. In addition, both absorption and scattering coefficients are examined by considering various vegetation types and coverage. The findings from empirical measurements facilitate a sensitivity analysis, with the use of the commercial software Odeon, of the absorption and scattering coefficients. Next, the empirical absorption and scattering coefficients are used on a model, developed in the commercial software Odeon, to see the effect of interior living walls on room acoustics. The aim of this study is to evaluate the application of interior living walls as a sustainable and acoustically beneficial material for buildings of any kind., Acoustical characteristics of interior living walls, Sound absorption coefficient, Sound scattering coefficient, Odeon software, Room acoustics, Living wall
Assessment of natural ventilation using whole building simulation methodological framework
Natural ventilation is a passive alternative to provide both indoor air quality and thermal comfort for the building’s occupants with low energy use. But at the same time, it is challenging for the building designers to implement natural ventilation strategies due to its complexity and highly dynamic behaviour, especially when it is compared with the mechanically ventilated buildings. Nevertheless, the use of naturally ventilated buildings is increasing along with the use of passive strategies, but depending on the complexity of the project, the designer still use rules of thumb for the implementation of natural ventilation strategies instead of a more comprehensive simulation-based approach. In theory, whole building simulation models (WBSM) are becoming viable tools to support natural ventilation design, particularly in the early stages of the project where the impacts of measures to implement a natural ventilation strategy are magnified. However, the only “evidence” of such level of support comes from individual case-study projects. Nevertheless, there is a lack of validation through measurement of the effectiveness of natural ventilation design in real buildings. This research will shed light into the “inner-workings” of natural ventilation models in WBSM to answer fundamental questions such as the following: How is wind data processed? How are envelope openings characterized? How are internal openings modelled? When and how is air buoyancy modelled in spaces? How are the coupled thermal and fluid mass transfers modelled to reflect the dynamic thermal responses of constructions and airflows? Therefore, a methodological framework is developed in order to provide the necessary knowledge for natural ventilation assessment. This framework is based on simulation (WBSM) and field testing. The proposed framework is tested in an existing landmark building in Vancouver. A WBSM of that building is developed, calibrated, and used to analyze how different factors that compose an integrated natural ventilation strategy (like the building shape, window shading, thermal mass, indoor spaces functionality and connectivity, and local climate) influence the thermal comfort of its occupants., Natural ventilation, Thermal comfort, Adaptive model, Whole building simulation models (WBSM)
Assessment of selected six stigma tools to improve food safety outcomes in a fresh-cut produce plant
Using a carrot processing line in a fresh-cut produce processing plant, it was found that Failure Mode and Effects Analysis (FMEA) provided a more accurate portrayal of the risk that is associated with a fresh-cut processing line than that provided by a conventional Hazard Analysis. This conclusion is based on the fact that FMEA clearly indicates the residual risk that is left after risk-mitigating activities are in place, and identifies the variables responsible for the remaining risk factor. This methodology also requires examination of the risk associated with all product and process changes that are involved in processing, with an integral part of this approach being the need for continuous improvement. FMEA, therefore, has the potential to decrease the likelihood that food processors will sell contaminated food to consumers because they have not detected when their biological hazards are not being adequately controlled, a classical type 2 error. It was also demonstrated that FMEA required a rating of the hazard detection method which drives the need to examine detection methods for hazards. In this example, a Run Chart was used to indicate changes in the microbiological status of a fresh-cut processing line. While the Run Chart successfully indicated this change, the information gained was not useful for showing the presence of a significant biological hazard. It was determined that this occurred because the information was not provided sufficiently in time to prevent the sale of contaminated carrots to customers. Use of a Defect Opportunity Checklist (DOC) was assessed to detect defects in a sanitation process; in effect, whether or not planned activities were being followed. This information was subsequently analyzed and an improvement plan was developed. While the DOC successfully performed this function, it was not adopted by the processing site because the current methods for verifying the sanitation indicated that the process was acceptable. This suggests that there may be limited acceptance of FMEA and DOC by food processors if it is perceived they perceive that their hazards are fully controlled by their existing food safety methodologies.
Comparing soil nematode composition in bluebunch wheatgrass P. spicata root to the occurrence of invasive plants C. stoebe and L. dalmatica
The viability of native bunchgrass ecosystems throughout the PPxh BEC subzone and in Kenna Cartwright Park (KCP) in Kamloops B.C. are under threat by invasive plants. Once established, invasive plants are difficult to eradicate and can predominate the landscape. I collected soil samples from a relatively undisturbed bunchgrass reference site composed of native bluebunch wheatgrass (Pseudoroegneria spicata), and I collected soil samples from a bunchgrass site occupied by the invasive plants, spotted knapweed (Centaurea stoebe) and dalmatian toadflax (Linaria dalmatica), to compare the soil nematode communities. My results reveal differences in the community-level biodiversity and abundance of soil nematodes between sites. The Maturity Index and the Plant Parasitic Index indicate that the native bunchgrass site had a “Structured” soil food web and that the site occupied by invasive plants had a “Basal” soil food web. My results indicate soil nematodes are useful as bioindicators of soil properties and these data provide useful criteria to help prioritize sites for ecological restoration., Nematology, Invasive plants, Pseudoroegneria spicata, Biological indicators, Ecological restoration
The effect of mowing and hand removal on the regrowth rate of Himalayan blackberry (Rubus armeniacus)
Himalayan blackberry (Rubus armeniacus Focke) is an invasive species in the Pacific Northwest. Mowing and hand removal are two of the common treatments used for controlling Himalayan blackberry. I examined the effectiveness of mowing, hand removal, and control treatments by measuring the mean number of stem and mean stem length during a growing season. Treatments were applied on March 2017. Bi-weekly sampling was from April to August 2017. Data were analyzed with a two-factor split-plot Analysis of Variance (ANOVA) test. The overall trend showed no statistically significant difference between mowing and hand removal treatments in one growing season. Integrated treatments (e.g. mowing + hand removal + planting) are recommended to be used to effectively reduce Himalayan blackberry cover because one removal treatment showed to be insufficient to eliminate Himalayan blackberry., Himalayan blackberry
The effects of canopy closure on precipitation throughfall
Since the 1860s the watershed of Spanish Bank Creek has experienced many ecological disturbances due to extensive old-growth logging and urban development. Most notably, these disturbances have altered the vegetative composition and hydrology throughout the watershed. The historic old-growth forest has been replaced by species typical of earlier seral stages, as well as invasive species such as English ivy (Hedera helix). This disturbed vegetation mosaic is characterized by an arrested ecological trajectory that perpetuates degraded conditions. Urban development has eliminated over a third of the historic length of Spanish Bank Creek and storm drains were installed to direct residential drainage into the stream. The combination of a disturbed forest and degraded hydrology intensifies runoff and associated sediment transport, and decreases the hydraulic retention time of the watershed. This has led to a significant decline in abundance of chum, coho, and cutthroat salmonids in Spanish Bank Creek. Previous research has established how trees partition precipitation into throughfall, stemflow, and interception, however there are few studies examining the effects of canopy closure on throughfall within the context of ecological restoration. Thus, the objective of this paper is to determine if increasing canopy closure can be used as a restoration model to decrease throughfall, and consequently increase the hydraulic retention time of the watershed. Results indicated that greater canopy closure was associated with decreased precipitation throughfall. From these results I formulated a restoration goal and several treatments that would increase canopy closure, and also ameliorate the degraded vegetative composition and hydrology of the watershed. The restoration treatments prescribed in this paper constitute five years of physical enhancements from which self-sustaining biological processes will continue to restore ecosystem function and structure. Successful implementation of these restoration treatments will positively affect regional biota, as well as users of the Pacific Spirit Regional Park who come to recreate, learn, and connect.
Evaluation of educational-software and paper-based resources for teaching logical-thinking skills to grade six and seven students
Guided by the objectives of investigating whether there were any differences between the effectiveness of the paper-based materials and educational software in teaching logical-thinking skills and transferring those skills to new problems and determining the efficacy of the paper-based materials and educational software in teaching logical-thinking skills and transferring those skills to new problems, a mixed-method research approach was used. A qualitative assessment was conducted to ascertain the appropriateness of the materials and a quantitative assessment was done using a pre-test, post-test, experimental design to assess the effectiveness of the materials in teaching logical-thinking skills. Based on the qualitative analysis, after the initial materials were modified through the information gained from the pilot students and changes were put in as suggested by the reviewers through their iterative reviews of the materials, it was determined that the reviewers considered that the events of instruction addressed in this intervention (gaining attention, informing the learner of the learning outcome, presenting the material, providing learning guidance, eliciting the performance, providing feedback, assessing performance, and enhancing retention and transfer) provided the attributes needed to effectively teach the logical-thinking skills of classification, analogical reasoning, sequencing, patterning, and deductive reasoning. For the quantitative analysis, one-way ANOVAs were performed to compare an experimental group learning from educational software (32 students), an experimental group learning from paper-based materials (32 students), and a control group (32 students). Given significance was found between the groups, Tukey HSD Post Hoc Tests were done. For each test, the subjects taught through educational software and those taught through paper-based materials scored significantly higher in logical-thinking ability than the control group, except for the subskills of patterning and deductive reasoning for the subjects learning through educational software, and the skill of deductive reasoning for the subjects learning through paper-based materials. For the transfer learning scores, the subjects learning through paper-based materials scored significantly higher than the control group. There were no significant differences between subjects taught through paper-based materials and those taught through educational software on any test. Based on paired samples t-test results, the subjects learning from educational software and those learning from paper-based materials had significant percentage gains on all of their pre-test to post-test scores, except the subjects learning through paper-based materials showed no significant gains on the sequencing and deductive-reasoning skills., Logical thinking, Instructional design, Qualitative analysis, Quantitative analysis
Geochemical and biological response of an intertidal ecosystem to localized restoration efforts
Geochemical and biological attributes of three intertidal areas in the Squamish Estuary with different levels of disturbance (low, medium, and high) were assessed to determine short-­term ecosystem responses to localized restoration efforts conducted one year previously on a former log handing site. Sediment and macroinvertebrate variables were analyzed among sites to characterize the ecosystems response and provide insight on the nature and process of an assisted successional trajectory. Invertebrate composition and biomass were lowest on the site with the highest level of disturbance. The high disturbance site also contained the highest percentage of fine sand (0.0067 mm to 0.25 mm). This confirms that in the short term there are distinct site responses to disturbance and ameliorative restoration efforts – even in a highly dynamic estuarine environment. The medium site contained more invertebrates than the low disturbance site indicating that something other than localized disturbance is affecting the invertebrate community on the low site. All sites exhibited a less-­rich and less diverse invertebrate community than that of historical records (circa. 1970-­1980). Invertebrate community in the east delta today is more typical of estuarine environments with higher salinity levels -­ which indicates more widespread levels of disturbance throughout the Estuary is affecting the study sites. This study highlights the importance of considering temporal and spatial scales when setting restoration goals, objectives and creating monitoring plans. Additional monitoring of sediment, invertebrate, and other variables on restored and reference sites is recommended to characterize typical recolonization and reassembly attributes of restoring intertidal estuaries in coastal British Columbia. This would provide evidence and rigor in determining effective restoration techniques and management strategies for a critical and increasingly threatened ecosystem., Macroinvertebrates, Restoration, Sediment, Benthic ecology, Estuaries, Intertidal flats
Hygrothermal performance of super-insulated double-stud wood frame wall assemblies
In cold climates, much of wood-frame building enclosure durability failures and indoor air quality issues stem mainly from excessive moisture within enclosure components and these issues are more pronounced in buildings with higher levels of thermal insulation, with frequent mold and fungal growth complications. Nevertheless, buildings have been increasing their insulation levels (and this trend is expected to continue) due to climate change, depleting natural resources, ever-rising energy prices and growing expectation for occupants’ comfort and health. Incorporation of insulation materials with higher moisture storage and buffering capacities and also employing vapour retarders that can let walls dry out to both interior and exterior spaces are potential solutions. While the hygrothermal behaviour of these insulation materials have been extensively tested in material labs and computer modeling projects, their actual performance in different climatic zones demands more field experimental studies. In this study, a field experiment was designed to assess hygrothermal behaviors of five highly insulated test wall panels under Marine climatic zone of, Burnaby, British Columbia. Full size wall panel specimens of ‘double-stud’ wood-frame were instrumented with moisture and temperature sensors and filled with Dense Cellulose Insulation (DCI) and Low-Density Spray Polyurethane Foam Insulation (LD SPFI) under different vapour control layer scenarios of 4-mil Polyethylene film, Smart Vapour Retarder (SVR), and none. All test panels were exposed to the 4 controlled indoor and the actual outdoor climates and their hygrothermal response was recorded and analysed from 01 Sept 2016 to 31 May 2017. The experimental results suggested DCI is a proper insulation material provided that it is equipped with a dedicated interior vapour barrier. The results also suggested while both DCI had LD SPF had acceptable moisture behaviour; DCI had slightly better performance than LD SPF. As for vapour control strategies, Smart Vapour Retarder (SVR) did not show an obvious advantage over 4-mil Polyethylene film and in some cases was slightly outperformed by polyethylene hygrothermally. As a general comment, the exterior sheathing board, plywood had the highest moisture activity and all other components, mainly the exterior and interior studs and plates remained in safe moisture ranges throughout the test period., Insulation, Dense Cellulose Insulation, Low-Density Spray Polyurethane Foam Insulation, Hygrothermal performance
Hygrothermal propertied of building materials at different temperatures and relative humidities
This research project investigated and measured a set of hygrothermal characteristics of several building materials commonly used across the North America. This study examined the behavior of building materials under various climate conditions other than what is proposed by the standards. Improving available standard test methods by using state-of-the-art equipment, enabled me to measure thermal conductivity, sorption isotherms, water vapor permeability and water absorption coefficient of tested materials under nine different combinations of temperatures from iv 3°C to 45°C and relative humidities from 50% to 90%. The results clearly present dependency of material properties on varying temperature and relative humidity. For example, thermal conductivity, vapor permeability and water absorption coefficients of all tested materials increased with respect to temperature, while the sorption isotherms of all materials decreased when temperature rose. The obtained results from this research can be utilized in Heat, Air and Moisture (HAM) modeling to improve effective and realistic analysis hygrothermal and energy performance of whole buildings.
Identifying temporal trends and mechanisms for successful reforestation on former agricultural land
This study investigates the outcomes of restoration efforts completed on retired agricultural land in Southwest Ontario. Sites acquired by the Nature Conservancy of Canada were planted to kickstart succession to native deciduous forests, but the results of the plantings are mixed. Analysis of soil conditions indicated that low levels of soil organic carbon were correlated to low water content and high density unfavourable for plant growth. Analysis of remotely sensed imagery was done to assess and compare vegetation cover to reference conditions at Walpole Island First Nation. Analysis revealed that successful restoration was dependent on multiple soil characteristics, but conditions correlated to higher total organic carbon favoured greater vegetation cover. Remote sensing data revealed that succession towards tree canopy development was accelerated compared to passive restoration, and a shaded understory was established approximately 8-12 years following restoration. Future work can expand on succession and the effects of other restoration treatments., Soil, Reforestation, NDVI, Agriculture, Restoration, Secondary succession
Investigating regeneration in a raised ombrotrophic bog after peat extraction
Burns Bog is a raised ombrotrophic bog in Delta, British Columbia and faced with myriad disturbances. This study is focused on the impact and restoration of peat extraction by the Atkins-Durbrow Hydropeat method. Depth to water table, relative abundance and distribution of vegetation, and the degree of peat decomposition at consistent-depth intervals were investigated to elucidate the status of passive and active ecological restoration in three fields previously harvested for peat approximately one decade apart and compared to a fourth unharvested field. Summary statistics, Redundancy Analysis, and regression were used to compare restoration status and trends in hydrology, vegetation composition, and peat accumulation. A lag period between cessation of harvest and implementation of restoration, coupled with rapid anthropogenic climate change, serve as impediments to restoration here. Intervention in the form of improved rainfall retention, assisted recolonization, and the introduction of nurse species are recommended to improve bog function and resiliency., Atkins-Durbrow Hydropeat method, Ditch blocking, Ecological restoration, Peat extraction, Raised ombrotrophic bog, Burns Bog
Model-based coupling of air and hydronic system operation in a high performance academic building
This research is motivated from preliminary teamwork on analyzing the “Performance Gap” of three high-performance buildings, which are currently under operation. All three buildings are facing operational challenges that are not unusual considering the complexity of their systems. However, evidence from design documents, an existing energy model, and operational data suggests that their performance is not entirely reflecting the design intent. This research follows the premise that there is a need to design buildings as systems-of-systems to be able to understand, interpret, quantify, design, and fine-tune the dynamic couplings between systems. This research was dedicated to a high-performance academic building (HPAB) – one of the above three buildings – as a case-study to gain understanding on the complexities of systems coupling, and learn and apply dynamic simulation-based systems coupling tools and methods. The main focus of the study is the classrooms because of the existing evidence on the significant impact of indoor environmental comfort on student performance in academic facilities. The HPAB case-study building incorporates, at the source side, ground-coupled water-to-water heat pumps (WWHP) and solar-thermal as primary means of heating, with boiler used as a backup source. Cooling is provided by the cold side of the WWHP system. On the demand side, heating and cooling are delivered via thermally active radiant floors; while air handling systems take care of the ventilation and de/humidification needs, and provide supplementary heating and cooling. The building was initially designed to rely on natural ventilation for summer cooling; however, designers realized that natural ventilation alone was not able to meet the building cooling demands in the summer. Nevertheless, the building has operable windows and a central atrium that seems to be collecting the air from the individual spaces and exhausting it after some heat recovery. The thermally active building is not adequately meeting the demands from some critical zones. Furthermore, the operation is not consistent with the reduced hours of summer operation of an academic building. These and other observations on the building indicate that the air and radiant systems are not operating in synergy. Existing industry practices in building controls systems, and the research literature show limited evidence of efforts to attempt to harmonize these two complementary systems. Simulation was used to re-create the HPAB building’s mechanical system response in two levels: a classroom-level model, and a Whole Building Energy Model (WBEM). The implementation was in EnergyPlus modeling software. Design documents, and historic operational data from the building automation system (BAS) were used for calibration. In this work, various features of Energy Management System (EMS) module of EnergyPlus has been utilized to create a responsive mechanical system control within the simulation. In the end, the typical responses of the building spaces could be accurately recreated in the simulation for both models. In the next step, testing different controls approaches – labelled as Strategies – and comparing them with defined comfort and stability metrics showed that harmonizing the air and radiant systems, in addition to increasing the consistency of the radiant system operation, results in improvement to the system operation without sacrificing the comfort. This research explores the challenges of employing a WBEM to assist building design decisions by accounting for the building dynamics and enabling the coupling and tuning of systems parameters and control strategies through simulation. The research demonstrates the benefits of improved operational control sequences that are more in tune with the building’s design intent.
Phytoremediation of contaminated soils
Phytoremediation poses an ecologically friendly and cost-effective alternative to other remediation methods such as chemical or thermal treatment. However, in contaminated sites such as retired oil wells and brine spills, it is common to have a co-contamination of salt and polyaromatic hydrocarbons (PAHs). The co-contamination of salt and PAHs may decrease the rate and effectiveness of bioremediation. Here we investigated the effect soil salinity has on the rate of phytoremediation, plant survivability and biomass. A 90-day greenhouse study was performed, growing alfalfa (Medicago sativa L.) in soils treated with varying salt (NaCl) concentrations in the presence of pyrene and benzo[a]pyrene. No significant differences were observed in the presence or absence of PAHs. Salt treatments has significant affects on plant biomass, nodulation, and successful germination., Bioremediation, Polyaromatic hydrocarbons, Alfalfa, Salt, Phytoremediation
Plant facilitation effects as a potential restoration tool in riparian ecosystems in Southwestern British Columbia
This study began to investigate potential facilitative effects among shrub species in riparian ecosystems in southwestern British Columbia. I ran two concurrent studies. Six plots for each of four treatments were established at the Coquitlam River Wildlife Management Area. The first two treatments compared the survival, growth, flowering, and herbivory rates of planted twinberry seedlings in plots where the shrub layer was removed to plots where it was not. The other two treatments compared the survival, growth, leaf loss, flowering and herbivory rates of snowberry plants in plots where the salmonberry upper shrub layer was removed to those where it was not. No significant differences between the measured parameters in any of the treatments were found. These results are discussed in the context of the riparian forest ecosystem and current facilitation theory. The results are then used to inform an ecological restoration plan for the Suwa’lkh School Forest., Facilitation, Riparian forests, Native vegetation, Symphoricarpos albus, Lonicera involucrate, Rubus spectabilis, Ecological restoration
RC-network based transient calculation method for thermal bridge analysis of multi-dimensional assemblies
Hourly dynamic energy performance study of buildings requires an in-depth understanding of dynamic thermal performance of building envelope assemblies. While two and three-dimensional building envelope thermal bridges have a great impact on whole-building energy simulations, heat storage capacity of the layers has also a significant influence. State of the art research has confirmed necessity of accurate thermal storage behavior analysis of building envelope assemblies in dynamic hourly building energy simulations. To-date, a number of studies have been conducted on the simplification of transient behaviour prediction of one, two and three-dimensional building envelope assemblies. In this study, the previous equivalent and simplified models for prediction of dynamic behaviour of building enclosure are reviewed, and an improved equivalent model based on frequency responses of RC-Network (FR-RCN) is presented. The model utilizes thermal RC-Network with three unknown resistances, two known resistances, and four unknown capacitances. The frequency responses of building envelope assembly are calculated either analytically (one dimensional assemblies), or numerically using COMSOL (two/three dimensional assemblies). Eureqa, a software which leverages evolutionary algorithms, is utilized in order to generate optimized unknown RC-Network resistances and capacitances considering the calculated frequency responses of the assembly. In this study, one light weight single-family home, one mass type structure high-rise building, and selected steel construction assemblies in climate zones 2 and 6 have been considered. A simple approach is also presented for the generation of equivalent FR-RCN models of variable insulation thickness assemblies. The comparison between the transient results calculated from the equivalent FR-RCN and COMSOL simulation shows good agreement. The performance of FR-RCN method is compared with other selected equivalent models, and an improvement in accuracy is confirmed., RC-Network, Multi-dimensional assemblies

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