19614 research outputs found
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UVic Convocation June 14, 2024 – 2:30 pm
No full textStudents from the faculties of Graduate Studies and Science.UndergraduateUnreviewe
Seismic evaluation of high-capacity shear walls used in mid-rise light wood frame buildings
Get PDFThe primary construction method for single-family homes and low-rise multi-family residences in North America is characterized by the prevalent use of light wood framing. The increasing urban population and the imperative to achieve sustainability goals demand permitting taller structures in regions previously marked by low-rise building practices. Since 2009, the Building Code of British Columbia has raised the storey limit of residential light wood frame buildings to 6 storeys. Adopting the same approach, in 2015, the National Building Code Canada (NBCC) also allowed the design and construction of wood-framed buildings up to 6 storeys. The increase in height leads to more flexible structures, potentially necessitating a more robust shear load-resisting system. While light wood frame structures have, by and large, performed well during earthquakes, the evolution in construction practices creates additional demand on the lateral load-resisting system. This calls for innovative designs that boost the lateral resistance of light wood frame shear walls, especially for buildings located in high seismic zones. The seismic force-resisting system of light wood frame buildings consists of studs, sheathing panels and fasteners, which are usually nails. This system is commonly known as light wood frame shear walls. In order to enhance the seismic performance of light wood frame buildings, modifications need to be made to the conventional shear wall system.
This dissertation explores the implications of a novel light wood frame shear wall named High-Capacity Shear Wall (HCSW). The introduced HCSW has two rows of fasteners along sheathing edges. Through comprehensive analyses, this research adopts a testable approach to the investigation of HCSWs under seismic loads. This research program consists of three parts.
The first part of the study addressed the effect of the loading protocol (namely ISO, CUREE, and SPD) and loading rate on the characteristics of timber nail joints. Since nail joints are one of the key components that control the lateral performance of light wood frame shear walls, it is of paramount importance to determine how different loading rates and protocols can influence the mechanical properties of the system. Accordingly, 96 nail joint samples were tested under monotonic and reversed-cyclic loading. The findings of this part of the research laid the foundation for the reversed-cyclic loading testing program of HCSWs, which is the second part of the study.
The second part of this research study delved into evaluating the seismic performance of HCSWs through conducting full-scale experiments. The experimental program consisted of 10 full-scale shear walls (9 HCSWs and 1 standard shear wall), and the test matrix included specimens with different sheathing thicknesses, nail diameters, and nail spacing. Test results showed that HCSW had 1.8–2.0 times the lateral load resistance of a standard shear wall (also known as the regular shear wall) with the same sheathing thickness, nail diameter, and nail spacing. The initial stiffness and ultimate displacement of the HCSWs were also greater than those of the comparable standard shear wall. Based on seismic equivalency criteria, shear walls with two rows of nails (i.e. HCSWs) could be assigned a design value of the comparable standard shear wall multiplied by a factor of 1.7.
In the last part of the study, the seismic performance of light wood frame buildings with HCSWs was investigated. The full-scale reversed-cyclic loading test results revealed that the ductility ratio of some HCSWs could be lower than that of the regular wall based on the ASTM D7989 method. This method is in fact a simplified and straightforward method for assessing the behaviour of light wood frame shear walls. Thus, a more comprehensive seismic evaluation can employ the time-history analysis of buildings following available guidelines. Consequently, the seismic performance of 1-storey and 6-storey light wood frame buildings under 12 archetypes undergoing 22 ground motions suggested by FEMA P695 was evaluated. Incremental Dynamic Analysis (IDA) was performed to evaluate the collapse capacity of archetypes. Also, the effect of initial stiffness on collapse margin ratios (CMRs) and maximum inter-storey drifts (MISD) at the design level was studied. The results showed that utilizing HCSWs improved the collapse capacity of both low-rise and mid-rise buildings. Models with HCSWs demonstrated larger CMRs (with a maximum of 2.47). Additionally, it was observed that the increase in initial stiffness could reduce the MISD at the design level as low as 0.42%. The findings of this study prove that the use of HCSWs enhances the seismic capacity of light wood frame buildings (using the same R_d and R_o factors of regular shear walls) in regions of high seismicity.Graduate2025-07-1
The production, trade, and consumption of pictorial pottery in Late Helladic IIIC
Get PDFThe collapse of the Mycenaean palatial administrations at the end of the 13th century BCE marked a period of significant transformations in social organization and interregional mobility across mainland Greece. The developments and innovations of this period were accompanied by the revival of Mycenaean pictorial style pottery. This decorative style employed figural motifs on vessels primarily intended for use in commensal social activity and was produced and traded across mainland Greece. Its study thus prompts consideration of regionalism, social ideology, and exchange in the post-collapse period: the present thesis examines the 12th century BCE rise of the pictorial style in the context of these themes.
I utilize the pictorial style pottery from the post-palatial settlement of Eleon in Eastern Boeotia as a primary case study. Among the large corpus of Late Helladic (LH) IIIC ceramics unearthed at the site is included a sizable and unpublished body of pictorial style pottery comprising 50 fragmentary vessels decorated with a variety of figural motifs. The study of pictorial pottery has historically focused on iconographic analysis and elements of stylistic development, often without consideration for the relationship between iconography, the site of production, and the movement of the pottery itself. Drawing on previously published neutron activation analysis conducted on ceramic materials from Eleon, the thesis responds to this trend in the scholarship by presenting the results of a macroscopic fabric study, integrated with iconographic analysis, that allows for attribution of provenance to the pictorial style pottery from the site.
I contextualize my findings by comparing Eleon’s pictorial pottery with that from Lefkandi and Mycenae, highlighting the stylistic trends and interregional motif preferences present in the post-collapse landscape. My macroscopic fabric study attributes a significant portion of Eleon’s pictorial pottery to Euboean production centers, attesting to a high degree of interregional exchange. This is corroborated by stylistic elements associated with the Euboean workshops. Eleon’s locally produced pictorial material reflects the predilection of Boeotian workshops for producing fish and bird motifs, while the Euboean workshops are shown to be the exclusive source of chariot and horse iconography consumed in LH IIIC Boeotia, supporting the recent suggestion that a limited number of centers produced chariot kraters. Stylistic continuity and reflections of palatial iconography in the pictorial art of post-palatial communities are also suggested to be indicative of a relationship between workshops of the pre- and post-collapse periods.
Lastly, I investigate the function of pictorial pottery within post-palatial communities. The main shape decorated at all sites is the ring-based krater (FS 281/282), a vessel used for the mixing of wine. Contextual analysis of the pottery shows that it is found primarily in domestic structures and more rarely shrines. I therefore propose that pictorial iconography was primarily seen during communal acts of drinking across Greece and less often in ritual contexts at sites such as Eleon and Kalapodi.Graduat
We Are Not Stones: Land, Indigenous Agency, and Colonialism in Williams Lake BC, 1821-1881
No full textThis project explores the complex realities of colonialism at Williams Lake from 1821-1881, taking a microhistorical approach to the study of broader themes in BC History. It seeks to analyze the transformation of the Williams Lake area from an Indigenous to a settler-controlled space by following the interactions between the T'exelcemc of the Secwepemc Nation and various colonial systems including the Hudson's Bay Company, the BC Colonial and Provincial Governments, and the Catholic Church. Indigenous agency is a central focus, particularly the letters of Chief William detailing the plight of his people caused by the theft of their land and the failure of the government to establish a reserve for over twenty years.Jamie Cassels Undergraduate Research Awards (JCURA)UndergraduateReviewe
Head-Dependent Asymmetries in Central Salish Prosody
No full textThis research presents an Optimality Theory (OT) analysis of three prosodic systems found in a number of Central Salish languages. The mapping of moraic structure to foot structure shows a parallel pattern whereby the head syllable licenses more complex moraic structures than the dependent syllables. The difference between head and dependent syllables can be enforced by moraic coercion, where a post-schwa intervocalic resonant is incorporated into the head syllable in Sḵwx̱wú7mesh (see Dyck, 2004). It also accounts for compensatory lengthening in ʔayʔaǰuθəm (see Blake, 2000) and foot-form in SENĆOŦEN (see Leonard, 2019). There is variation in how the head syllable expresses complexity, but interestingly, the dependent is banned from any (complex) moraic structure. These patterns are formalized in OT by a constraint which penalizes dependents that have a moraic content equal to, or greater than, their heads.Jamie Cassels Undergraduate Research Awards (JCURA)UndergraduateReviewe
Long-term successional subculture dynamics and their effects on the proliferation efficiency, embryogenic potential, and genetic stability of embryogenic tissues in Larix principis-rupprechtii Mayr
Get PDFLarix principis-rupprechtii Mayr, a coniferous species indigenous to Northern China, possesses significant ecological and economic value. Somatic embryogenesis offers a pathway with significant potential for large-scale propagation, long-term germplasm conservation, and genetic transformation in L. principis-rupprechtii Mayr. However, it remains unclear whether significant variations occur in embryogenic tissues during long-term successive subculturing, which could impact the productivity of somatic embryos. This is a pivotal concern that lacks comprehensive understanding. In this study, three embryogenic cell lines were used to explore the dynamics and relationships among proliferation rate, pre-treatment proliferation rate, and embryogenic capabilities across a series of 32 subculturing cycles. Proliferation rate, pre-treatment proliferation rate, and somatic embryo maturation rate showed no significant correlation with subculturing cycles. However, there was a positive correlation between subculturing cycles and pre-treatment proliferation rate and a negative correlation with somatic embryo maturation rate in the BFU1 cell line. In addition, we utilized ten SSR molecular markers to investigate the genetic stability in embryogenic tissues during long-term subculturing. No genomic variations were detected in any of the three embryogenic cell lines, which suggests that the observed phenotypic dynamics during subculturing may not be primarily driven by genomic alterations. This study provides novel insights into the dynamics of the long-term culture of embryogenic tissues, laying a foundation for the optimization and application of somatic embryogenesis techniques in L. principis-rupprechtii Mayr and potentially other coniferous species.This work was supported by the National Natural Science Foundation of China (No. 32371834), the National Natural Science Foundation of China (No. 32271836), Key R&D Program of Heibei Province, China (20326333D).FacultyReviewe
Temporal change of pH in response to nutrient source and land type in agricultural soils
Get PDFBiological amendments influence soil pH, which is shaped by former land use. pH is a measure of hydrogen ion concentration that impacts the nutrient acquisition of plants. The variation in soil pH affects ecosystems differently; forests tend to be acidic due to the presence of enzyme-producing fungi, while grasslands lean towards alkalinity from enzymes produced by alkaline favoring bacteria. Synthetic fertilizers, over time, acidify soils, affecting nutrient uptake. This study investigated the impact of biological and synthetic nutrition treatments on soil pH in vineyards. Applying compost, compost teas and extract for the biological treatment over four months in the summer of 2022. Soil samples were collected bi-monthly, and pH measured using standardized protocols. Results revealed differing effects of the treatments on pH in former forest and field lands. Statistical analyses demonstrated significant pH changes in synthetic-treated fields, while treatments-maintained pH within optimal ranges for grape vines. These findings could be in part to the soil microbiology and recent land conversion that significant influences on pH dynamics. Continued research is warranted to understand the long-term effects of nutritional amendments on soil pH in dynamic ecosystems.Jamie Cassels Undergraduate Research Awards (JCURA)UndergraduateReviewe
Hardware Architecture for Accelerating Frequency-Domain Ultrasound Image Reconstruction
No full textUltrasound is a widely employed biomedical imaging modality enabling non-invasive, low-cost, and real-time diagnostics. In a typical ultrasound system, a multi-channel transducer emits sound waves into the medium and then records returning echo signals that are subsequently converted into an image of the subsurface structure. Coherent plane-wave compounding (CPWC) is one of the latest ultrasound imaging techniques that involves emitting multiple plane-wave pulses at various angles and then combining angle-specific reconstructed image data into a final frame. This approach offers high data acquisition rates (e.g., hundreds or even thousands of raw data frames per second) that are crucial for capturing fast-changing phenomena in the imaged medium.
High data acquisition rates should be matched with fast data processing to increase the frame rate of reconstructed, or beamformed, image frames. One example of highly efficient plane-wave beamforming methods is the Temme-Mueller algorithm that operates in the Fourier domain. This thesis describes a novel pipelined hardware architecture for accelerating the execution of this algorithm. The proposed design has been coded in VHDL and implemented on a modern Xilinx® field-programmable gate array (FPGA), taking advantage of Xilinx® intellectual property (IP) core reuse to reduce development time.
Our architecture is capable of producing over 1,300 beamformed frames per second, where each frame contains 256K complex-valued data points using the 32-bit floating-point representation for both real and imaginary parts. The correctness of our FPGA-based beamformer has been verified by comparing its output to the reference software-based implementation of the Temme-Mueller algorithm. This verification was done on an experimental ultrasound dataset available as part of the public-domain PICMUS evaluation framework. Our evaluation results demonstrate that the proposed design provides a promising alternative to the conventional GPU-based approach to high-frame-rate ultrasound image reconstruction, paving the way for future algorithmic and architectural enhancements.Graduat
Role of the PEST Domains in Proteasomal Degradation of Rett Protein: MeCP2
No full textLocated on the X-chromosome is the gene encoding the nuclear protein Methyl CpG binding protein 2 (MeCP2). The instability of this protein causes pleiotropic neurological abnormalities, including the debilitating neurodevelopmental disease Rett syndrome (RTT). MeCP2, an epigenetic regulator abundant in neurons, is involved in pleiotropic molecular interaction. Many deleterious mutations of MeCP2 impact its mRNA or protein levels. Neuron maturation and dendritic arborization are compromised when MeCP2 levels are out of the homeostatic range. The mechanisms the cell uses to maintain MeCP2 levels within a tight range have yet to be fully understood. Several hypotheses addressed the homeostatic mechanisms of MeCP2, which involve miRNAs, N-terminal degradation signals or N-degrons, and the PEST domains that act as degradation switches upon post-translational modifications (PTMs). Our lab hypothesized the involvement of MeCP2 PEST-mediated degradation as a mechanism of its homeostatic regulation; however, this hypothesis has yet to be experimentally proven. I experimentally tested the PEST-mediated degradation of MeCP2 with Rett-causing mutations by integrating MeCP2 constructs that have an altered or deleted PEST domain and used microscopy, FRAP analysis and western blotting to characterize in vitro how these constructs behave relative to WT and mutated MeCP2. MeCP2 has Rett-causing mutations that cause lower protein levels, such as T158M; the PEST motif expedites its degradation as deleting it results in higher protein levels. Moreover, mutations that result in higher levels of MeCP2, such as R294X, show stronger DNA binding relative to WT, as assessed by NaCl fractionation. For the first time, we report that the Ct-PEST domain of MeCP2 plays a role in its degradation.Graduat
The optimal spatially-dependent control measures to effectively and economically eliminate emerging infectious diseases
No full textNon-pharmaceutical interventions (NPIs) are effective in mitigating infections during the early stages of an infectious disease outbreak. However, these measures incur significant economic and livelihood costs. To address this, we developed an optimal control framework aimed at identifying strategies that minimize such costs while ensuring full control of a cross-regional outbreak of emerging infectious diseases. Our approach uses a spatial SEIR model with interventions for the epidemic process, and incorporates population flow in a gravity model dependent on gross domestic product (GDP) and geographical distance. We applied this framework to identify an optimal control strategy for the COVID-19 outbreak caused by the Delta variant in Xi’an City, Shaanxi, China, between December 2021 and January 2022. The model was parameterized by fitting it to daily case data from each district of Xi’an City. Our findings indicate that an increase in the basic reproduction number, the latent period or the infectious period leads to a prolonged outbreak and a larger final size. This indicates that diseases with greater transmissibility are more challenging and costly to control, and so it is important for governments to quickly identify cases and implement control strategies. Indeed, the optimal control strategy we identified suggests that more costly control measures should be implemented as soon as they are deemed necessary. Our results demonstrate that optimal control regimes exhibit spatial, economic, and population heterogeneity. More populated and economically developed regions require a robust regular surveillance mechanism to ensure timely detection and control of imported infections. Regions with higher GDP tend to experience larger-scale epidemics and, consequently, require higher control costs. Notably, our proposed optimal strategy significantly reduced costs compared to the actual expenditures for the Xi’an outbreak.This research is funded by Major International (Regional) Joint Research Project of National Natural Science Foundation of China (12220101001) (YX), National Key R&D Program of China (2022YFA1003704, YX), National Natural Science Foundation of China (12071366, FX), Chinese Scholarship Council (CSC, FX), Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant (JM), NSERC Emerging Infectious Disease Modeling Grants (MfPH and OMNI) (JM). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.FacultyReviewe