MSpace
MSpace is the University of Manitoba’s Institutional Repository. The purpose of MSpace is to acquire, preserve and provide access to the scholarly works of University faculty and students within an open access environment.
Communities in MSpace
Select a community to browse its collections.
Recent Submissions
Item
Open Access
Design and experimental evaluation of cascaded metasurfaces
(2023-09-27) Gohel, Jayesh; Isleifson, Dustin (Electrical and Computer Engineering); Kordi, Behzad (Electrical and Computer Engineering); Mojabi, Puyan
Tailoring electromagnetic waves has various applications in wireless communications, medical imaging, and remote sensing. However, to be suitable for a given application, the spatial properties of electromagnetic waves need to be manipulated to fit that application. This is generally done by designing antennas based on the required performance criteria. Designing antennas for complicated performance requirements can be quite time-consuming as it may require extensive full-wave optimization. Alternatively, a metasurface can be used as it can systematically transform electromagnetic waves to what the designer desires. Electromagnetic metasurfaces are sheet-like structures consisting of artificial “atoms” called meta-atoms or unit cells, that are small compared to the operational wavelength. When electromagnetic waves interact with these unit cells, they are transformed based on the properties of the unit cells. The design of lossless and passive metasurfaces requires enforcing total power conservation (TPC) and local power conservation (LPC) to make sure that the power is conserved in the whole metasurface and at each individual unit cell. If a single metasurface cannot satisfy the required constraints, a metasurface pair, also known as cascaded metasurfaces, can be considered. In this thesis, a fully automated design approach is developed for cascaded metasurface system designs with external sources based on an existing design approach. The overall design is divided into macroscopic and microscopic steps. In the macroscopic step, an automated conjugate gradient (CG) optimization algorithm is developed with analytical expressions to arrive at the required surface properties of the cascaded metasurface system. In the microscopic step, the unit cells are physically realized by copper traces determined using a lookup table which was further optimized to achieve the desired forward scattering parameters for each unit cell. The electromagnetic wave transformation is then verified by modeling the cascaded metasurface system in Ansys HFSS software and performing the full-wave simulation. Finally, a cascaded metasurface system is fabricated and measured. This serves as one of the few fabricated cascaded metasurfaces reported in the literature. Planar near-field antenna range (PNFR) measurements are conducted to experimentally evaluate the performance of the cascaded metasurface system. The successful simulation and experimental verification confirm the working of the fully automated cascaded metasurface design algorithm.
Item
Open Access
Nutritional and environmental impacts of livestock production systems in Canada: a food systems perspective
(2023-09-20) Gunte, Kebebe Ergano; McGeough, Emma (Animal Science); Wittenberg, Karin (Animal Science); Aukema, Harold (Food and Human Nutritional Sciences); McAllister, Tim (Animal Science); McKinnon, John (University of Saskatchewan); Ominski, Kim; White, Robin
Meeting the challenge of providing a consistent supply of nutritious food for a growing global population is a significant issue facing humanity in the 21st century. Animal-sourced foods (ASF) play a vital role in global food security and nutrition, but their production is often criticized for its high resource demand and greenhouse gas (GHG) emissions. This study examined the relationship between animal production and the environmental and nutritional impacts of land use and dietary choices in Canada. Data regarding animal feed demand and land base requirements, nutrient composition, prices and GHG emissions of crop and animal-based products, human nutritional requirements, and socio-demographic factors affecting food choices were collected from various sources, including Statistics Canada, USDA, industry reports, and published literature. The research employed a combination of mixed research methods, such as multilevel mixed-effects probit regression, inverse probability weighted with regression adjustment, mathematical diet optimization techniques, and spreadsheet models for data analysis. The analysis demonstrated that Canada's total annual dry matter (DM) feed demand in 2016 was approximately 63.9 million t, requiring approximately 17.9 million ha of land. Diet optimization indicated that nutrient intake requirements of Canadian population could generally be met from the domestic food supply, except for certain fatty acids and vitamins. Omnivore, lacto-ovo, and lacto-vegetarian diets required more food to meet Recommended Daily Allowance (RDA) requirements and produced more GHG emissions than vegan diets. However, completely removing animals from Canadian farming systems and transitioning to vegan diets led to increased diet costs. Based on our analysis, the exclusion of red meat from diets resulted in statistically significant differences in the intake of 14 -17 nutrients, depending on the analytical approach used. Further, the risk of calcium, energy, potassium, and vitamin D inadequacy was higher for people who did not consume red meat, while potential inadequacy for magnesium, fiber, and vitamin A was lower for those that did. Sex, education, family status, and cultural background are important determinants of dietary choice among Canadians. These findings can help scientists, policymakers, farmers, and other stakeholders make informed decisions about how to achieve food security and sustainability in a changing world.
Item
Open Access
Local level flood management, risk reduction, and coping and adapting in the Red River Valley, Manitoba, Canada
(2023-09-17) Zaman, Jobaed Ragib; Walker, David (Environment and Geography); Islam, Faisal (Natural Resources Institute); Haque, C. Emdad
The purpose of this research was to study the pattern of flood preparedness, response and recovery, and the drivers of changes in flood management, i.e., coping and adapting, in the Red River Valley of Manitoba, Canada. I conducted my research following a case study approach with a qualitative research design. My study included the communities of St. Adolphe and Ste. Agathe in the Rural Municipality (RM) of Ritchot in Southern Manitoba. Techniques and instruments that were applied for data collection included Key Informant Interviews (8), Oral History Interviews (7), and Document Review.
The findings of the research revealed that local community-level flood preparedness, response, and recovery in the Province of Manitoba are primarily designed, governed, managed, and evaluated by Provincial government authorities using a top-down approach. Given that Canada has a long history of bailing out disaster victims, and as the approach has been generally non-participatory, community members show reluctance in taking precautionary measures, resulting in undesired losses and damages. The findings of my research also identified the major drivers of coping and adaptation measures for building flood resilience within the communities, which included: functioning partnerships among stakeholders, strong institutional structures that facilitate interactive learning, knowledge co-production, resource sharing, communication and information sharing, and infrastructure supports. However, there were only a few efforts to develop an institutional atmosphere conducive to spontaneous network development, yielding diverse coping and adaption strategies at the community level in the Province of Manitoba.
Item
Open Access
Mining impact and Indigenous protected and conserved areas
(2023-09-14) Onyeneke, Chima; Oakes, Jill (Environment & Geography); Cooper, Sarah (City Planning); Thompson, Shirley
Gold mining on pristine land that Indigenous people use for sustenance is a common practice in Canada, despite some of these lands being designated as Indigenous-protected areas. This study explores traditional land use protection versus natural resource extraction, looking at the Red Sucker Lake First Nation (RSLFN) region. I applied geographic information system mapping, analysis of transcribed audio interviews, and literature review methods in this study. Based on 21 map biographies of traditional land use of RSLFN interviewees’ transcripts focused on the preservation of traditional ecological knowledge (TEK), mining impacts, and traditional land use and occupancy (TLUO) of these 21 RSLFN people. Summary maps of the traditional land uses of 21 RSLFN people show sustenance and cultural activities on greenstone belts, designated by the province for mining. The interview analysis reveals exploration and mining activities impacting RSLFN’s traditional land and practices, causing spills and destroying personal property. The interviews also reveal community members’ desire to protect their land from mining activities for Indigenous knowledge preservation, ecosystem preservation, and traditional land use protection towards realizing Mino Bimaadiziwin (the good life). A change in governments’ policies on greenstone belts being restricted to mining development, which interferes with the traditional land use practices of affected Indigenous peoples, is needed.
Item
Open Access
Elucidating mechanisms of sulfamethoxazole sorption onto bentonite in the presence of fresh liquid swine manure dissolved organic carbon
(2023-09-11) Hansima, Charitha; Zvomuya, Francis (Soil Science); Farenhorst, Annemieke (Soil Science); Indraratne, Srimathie (University of Winnipeg); Amarakoon, Inoka
The extensive use of sulfamethoxazole (SMX) as a veterinary antimicrobial in the Canadian swine industry increases its occurrence in manure. Land application of swine manure enhances the dispersal of SMX in the environment, increasing the risk of antibiotic resistance development in bacteria, one of the focal human health emergencies of our times. Humic acid (HA) and fulvic acid (HA) from the dissolved organic carbon (DOC) fraction in fresh liquid swine manure influence the sorption of SMX onto smectite clays, hence the environmental fate.
This research aimed to elucidate the effect of fresh liquid swine manure DOC species in fresh liquid swine manure on SMX sorption onto bentonite. Specific objectives were to (i) elucidate the physicochemical characteristics of HA and FA isolated from fresh liquid swine manure DOC and (ii) assess their contribution to the mechanisms controlling SMX sorption onto bentonite clay.
Humic substances were extracted and characterized for their physicochemical properties. A batch sorption study with a randomized complete block design was used to quantify the SMX sorption, explicit clay-mineral surface and interlayer sorption, and probe fluorescence quenching in humic substances by SMX.
Results showed that FA was the dominant component of DOC in the fresh liquid swine manure examined in this study (10 FA: 1 HA). Thus, FA determined the major portion of organic matter coating on the mineral bentonite and binding of SMX. Spectroscopic analysis revealed that hydrophobicity (53.0% HA, 56.5% FA), hydrophilicity (34.0% HA, 35.1% FA), aromaticity (34.0% HA, 37.2% FA), and aliphaticity (66.0% HA, 62.7% FA) of the two humic substances were similar despite the differences in their functional groups. Solid state 13C-NMR data and X-ray Photoelectron Spectroscopic data revealed that the core and the surface of HA and FA secondary structures were substantially different. The orientation of functional groups in clay mineral-bound HA and FA and free aqueous HA and FA determined SMX sorption mechanisms. The abundance of surface-oriented phenolic functional groups in mineral-bound and free FA resulted in fluorophore quencher π-π electron-donor-acceptor interactions, cation and water bridging, and H-bonding. In contrast, the relatively high surface amide groups in HA structures allowed non-fluorophore quencher H-bonding, cation, and water-bridging mechanisms with SMX. Sorption data suggested the formation of extractable aqueous FA-SMX residues, whereas SMX complexed to aqueous HA is non-extractable. Spectroscopic data revealed a comparatively higher amount of -COOH functional groups in FA colloids, which made FA-SMX unstable and susceptible to breakdown in aqueous environments. SMX complexed with aqueous FA can be transported in rain and snowmelt runoff and leach into aquatic environments and subsequently desorbed. We suggest the storage of fresh liquid swine manure under aerobic conditions in open lagoons to oxidize FA functional groups or composting of the manure to hinder SMX sorption to FA before land application. Further, the transformation of FA to HA through humification under long-term storage may also contribute to reducing the sorption of SMX onto FA.