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

BCIT Thesis and other Required Graduate Degree Works

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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
Restoration of old forest characteristics in a 1957 spacing trial in the Malcolm Knapp Research Forest, British Columbia
Forest managers are interested in determining how stands that have been logged might be managed to restore features characteristic of forests in later-stages of development. Incorporating forest restoration into forest management enables the use of forest-management skills, such as silviculture and regeneration techniques, to manage individual stands for multiple objectives. Therefore, I performed a comparative analysis of large trees, very-large trees, large snags, very-large snags, and large CWD among three stand types (i.e., 60-yr-managed, 140-yr-natural, and 500-yr-natural stands). The 140-yr-natural and 500-yr-natural stands were used as reference conditions to guide the restoration of a 59-yr-managed spacing trial. All attributes differed among stand-types; however, large snags were the most similar attribute between 140-yr-natural and 500-yr-natural stands. Large trees were the fastest attribute to recover in 60-yr-managed stands, however mean values among stand-types still differed. This study highlights the potential of restoring old-natural attributes in younger-managed stands to increase ecological resiliency., forest, natural, managed, prescription, restoration, old-natural attributes
Sound living in Vancouver's laneway housing
Laneway housing is an innovative higher density housing form introduced to meet the City of Vancouver’s EcoDensity Charter. This form of residential occupancy was introduced without specific acoustical standards for construction. Noise concerns generally accompany increasing urban density, particularly in housing located close to transportation and activity centers. Laneways and laneway housing have environmental and architectural features that can contribute to noise levels exceeding criteria for healthy living. To advance the state of practice, this research first explores the sonic environment of laneways, including sound propagation, urban canyon effects, and sound sources. Second, this research investigates the acoustics of the laneway house, including outdoor-indoor sound insulation of facades, architectural features, and floor plan layout in relation to environmental noise sources. Empirical field measurements, the CMHC road traffic noise model and software modelling programs are used to investigate the acoustical environmental quality of laneway housing. Findings from case study investigation of four laneways and six laneway houses are evaluated against the CMHC noise criteria for healthy living. The various research tools are evaluated for accuracy and practicality as acoustic design tools for Vancouver laneways and laneway housing. The results of this study can inform laneway development planning (including benefits of laneway vegetation), laneway house design, building envelope construction, and policy guidelines as the City of Vancouver continues in its plans for sustainable densification., Acoustics of small buildings, Urban canyon effect, Road traffic noise, Laneway house acoustics
Sound transmission of wood frame split insulated rainscreen cavity wall assemblies
Exterior building envelope walls with rainscreen cavities are now required by British Columbia building codes. The introduction of the rainscreen cavity and optional external thermal insulation can alter sound transmission loss and consequently affect indoor sound levels in single and multi-family wood-frame housing. In this study, 57 exterior wall assemblies were built and acoustically evaluated using a hybrid sound intensity technique. The variables investigated were cladding material (vinyl, fibre cement board, and stucco), exterior insulation (mineral wool and XPS), exterior insulation thickness (1 ½" and 3"), cladding attachment type (resilient and non-resilient), and rainscreen cavity width (3/8" and 1"). The sound transmission class of the tested wall assemblies ranged from 37 to 52; the outdoor-indoor transmission class rating ranged from 26 to 37. Results indicated that the selection and the combination of the material layers were fundamental to sound transmission loss performance. Cladding material and cladding attachments influenced sound transmission and resulted in a broad range of overall performance. The split insulated rainscreen cavity wall assemblies presented higher transmission loss than single insulation walls, provided that the exterior insulation had sound absorbing properties. The best performing wall assemblies generally have high mass cladding, resilient cladding attachment, and 3" mineral wool exterior insulation (in addition to the interior cavity insulation). Given the research outcomes, in denser and noisier urban areas, a building envelope professional has additional options to design an exterior rainscreen cavity wall to meet thermal performance and acoustical criteria for exterior sound levels in wood frame buildings.

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