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Item A Highly Sensitive Chitosan-Based SERS Sensor for the Trace Detection of a Model Cationic Dye(MDPI, 2024-08-28) Vafakish, Bahareh; Wilson, LeeThe rapid detection of contaminants in water resources is vital for safeguarding the environment, where the use of eco-friendly materials for water monitoring technologies has become increasingly prioritized. In this context, the role of biocomposites in the development of a SERS sensor is reported in this study. Grafted chitosan was employed as a matrix support for Ag nanoparticles (NPs) for the surface-enhanced Raman spectroscopy (SERS). Chitosan (CS) was decorated with thiol and carboxylic acid groups by incorporating S-acetyl mercaptosuccinic anhydride (SAMSA) to yield CS-SAMSA. Then, Ag NPs were immobilized onto the CS-SAMSA (Ag@CS-SAMSA) and characterized by spectral methods (IR, Raman, NIR, solid state 13C NMR with CP-MAS, XPS, and TEM). Ag@CS-SAMSA was evaluated as a substrate for SERS, where methylene blue (MB) was used as a model dye adsorbate. The Ag@CS-SAMSA sensor demonstrated a high sensitivity (with an enhancement factor ca. 108) and reusability over three cycles, with acceptable reproducibility and storage stability. The Raman imaging revealed a large SERS effect, whereas the MB detection varied from 1–100 μM. The limits of detection (LOD) and quantitation (LOQ) of the biocomposite sensor were characterized, revealing properties that rival current state-of-the-art systems. The dye adsorption profiles were studied via SERS by fitting the isotherm results with the Hill model to yield the ΔG°ads for the adsorption process. This research demonstrates a sustainable dual-function biocomposite with tailored adsorption and sensing properties suitable for potential utility in advanced water treatment technology and environmental monitoring applications.Item A New Argument for Ethical Evidentialism(Springer, 2024-08-09) Zamulinski, BrianThis paper contains a new argument for evidentialism as an ethical rather than an epistemic doctrine. The argument relies on new developments in consequentialist thinking. The insights of the proponents of the moral encroachment thesis are used to show that we need higher standards of evidence, and to develop the concept of ethically sufficient evidence. It is demonstrated that prospectivism (subjective consequentialism) supports the contentions that we should not believe without ethically sufficient evidence, that we are permitted to believe when we have it, and that we are obligated to investigate to acquire it. It is argued that we do not have any obligations to believe. The ethical evidentialism argued for here is distinguishable from Clifford’s ethics of belief. Developing the doctrine clarifies some of our moral obligations, makes a positive contribution to prospectivism, and shows that evidentialism is better construed as an ethical doctrine.Item A new highly stable multifunctional two-dimensional Si2BN monolayer quantum material with a direct bandgap predicted by density functional theory(Royal Society of Chemistry [Society Publisher], 2024-07) Djamel, Bezzerga; Chelil, Naouel; Mohammed, Sahnoun; Gusarov, Sergey; Chang, Gap Soo; Naseri, MosayebIn this work, we present a novel two-dimensional (2D) Si2BN structure (2D δ-Si2BN) predicted using density functional theory (DFT). The proposed structure exhibits a unique double quasi-planar layer interconnected by covalent bonds, demonstrating lower energy compared to the previously reported planar Si2BN nanosheet. Our calculations, conducted at the HSE06 level of theory, reveal its semiconductor nature with a direct band gap of 1.24 eV at the gamma point. The 2D material exhibits exceptional light absorption in the visible region, prompting an exploration of its potential in photovoltaic applications. Remarkably, our findings indicate a maximum theoretical efficiency of 27.6%, underscoring its promise for renewable energy technologies. Furthermore, employing modern polarization theory, we unveil the ferroelectric properties of the Si2BN monolayer. Notably, a large out-of-plane polarization is observed. It was found that the unstrained 2D δ-Si2BN monolayer demonstrates an impressive out-of-plane spontaneous electric polarization of 28.98 × 10−10 C m−1, a value six times greater than previously referenced Janus materials. This remarkable enhancement in ferroelectric capabilities positions the Si2BN monolayer as a promising candidate for applications in next generation novel information storage, nano-electronic, and optoelectronic devices. These findings not only contribute to the understanding of the structural and electronic properties of the 2D δ-Si2BN monolayer but also highlight its potential for various technological applications, marking a significant advancement in the field of nanomaterials.Item Acidic microenvironments in waste rock characterized by neutral drainage: Bacteria-mineral interactions at sulfide surfaces(MDPI, 2014-03-21) Dockrey, John W.; Lindsay, Matthew B. J.; Mayer, K. Ulrich; Beckie, Roger D.; Norlund, Kelsey L. I.; Warren, Lesley; Southam, GordonMicrobial populations and microbe-mineral interactions were examined in waste rock characterized by neutral rock drainage (NRD). Samples of three primary sulfide-bearing waste rock types (i.e., marble-hornfels, intrusive, exoskarn) were collected from field-scale experiments at the Antamina Cu–Zn–Mo mine, Peru. Microbial communities within all samples were dominated by neutrophilic thiosulfate oxidizing bacteria. However, acidophilic iron and sulfur oxidizers were present within intrusive waste rock characterized by bulk circumneutral pH drainage. The extensive development of microbially colonized porous Fe(III) (oxy)hydroxide and Fe(III) (oxy)hydroxysulfate precipitates was observed at sulfide-mineral surfaces during examination by field emission-scanning electron microscopy-energy dispersive X-ray spectroscopy (FE-SEM-EDS). Linear combination fitting of bulk extended X-ray absorption fine structure (EXAFS) spectra for these precipitates indicated they were composed of schwertmannite [Fe8O8(OH)6–4.5(SO4)1–1.75], lepidocrocite [γ-FeO(OH)] and K-jarosite [KFe3(OH)6(SO4)2]. The presence of schwertmannite and K-jarosite is indicative of the development of localized acidic microenvironments at sulfide-mineral surfaces. Extensive bacterial colonization of this porous layer and pitting of underlying sulfide-mineral surfaces suggests that acidic microenvironments can play an important role in sulfide-mineral oxidation under bulk circumneutral pH conditions. These findings have important implications for water quality management in NRD settings.Item Adapting to Climate Change Through Source Water Protection: Case Studies from Alberta and Saskatchewan, Canada(Scholarship@Western, 2018) Patrick, Robert J.The protection of drinking water sources continues to gain momentum in First Nation communities on the Canadian Prairie. Through the identification of potential threats to drinking water sources communities are taking action to mitigate those threats. This article explores the extent to which climate change has been taken into consideration in recent source water protection planning community exercises. In addition, this article describes how source water protection planning has potential to enhance community adaptation strategies to reduce the impacts of climate change on source water and drinking water systems. Results are based on six case studies from Alberta and Saskatchewan.Item Adsorption of (Poly)vanadate onto Ferrihydrite and Hematite: An In Situ ATR–FTIR Study(American Chemical Society (ACS) Publications, 2020-03-25) Vessey, Colton; Schmidt, Michael P.; Abdolahnezhad, Mojtaba; Peak, Derek; Lindsay, Matthew B. J.Vanadium (V) has been a useful trace metal in describing Earth’s biogeochemical cycling and development of industrial processes; however, V has recently been recognized as a potential contaminant of concern. Although Fe (oxyhydr)oxides are important sinks for aqueous V in soils and sediments, our understanding of adsorption mechanisms is currently limited to mononuclear species (i.e., HxVO4(3–x)–). Here we use in situ attenuated total reflectance – Fourier transform infrared spectroscopy to examine sorption mechanisms and capacity for (poly)vanadate attenuation by ferrihydrite and hematite from pH 3 to 6. Adsorption isotherms illustrate the low affinity of polyvanadate species for ferrihydrite surfaces compared to hematite. Mononuclear V species (i.e., [HxVO4](3−x)− and VO2+) were present at all experimental conditions. At low surface loadings and pH 5 and 6, H2VO4− adsorption onto ferrihydrite and hematite surfaces results from formation of inner sphere complexes. At [V]T above 250 µM, adsorbed polynuclear V species in this study include H2V2O72− and V4O124−. Whereas, HV10O286−, H3V10O285−, and NaHV10O284− are the predominant adsorbed species at pH 3 and 4 and elevated [V]T. Surface polymers were identified on hematite at all experimental pH values, whereas polymeric adsorption onto ferrihydrite was limited to pH 3 and 4. These results suggest that hematite offers a more suitable substrate for polymer complexation compared to ferrihydrite. Our results demonstrate the pH and concentration dependant removal of (poly)vanadate species by Fe(III) (oxyhydr)oxides, which has implications for understanding V mobility, behaviour, and fate in the environment.Item Advances in mapping sub-canopy snow depth with unmanned aerial vehicles using structure from motion and lidar techniques(Copernicus Publications on behalf of the European Geosciences Union, 2019) Harder, Phillip; Pomeroy, John; Helgason, Warren D.Vegetation has a tremendous influence on snow processes and snowpack dynamics yet remote sensing techniques to resolve the spatial variability of sub-canopy snow depth are lacking. Unmanned Aerial Vehicles (UAV) have had recent widespread application to capture high resolution information on snow processes and are herein applied to the sub-canopy snow depth challenge. Previous demonstrations of snow depth mapping with UAV Structure from Motion (SfM) and airborne lidar have focussed on non-vegetated surfaces or reported large errors in the presence of vegetation. In contrast, UAV-lidar systems have high-density point clouds, measure returns from a wide range of scan angles, and so have a greater likelihood of successfully sensing the sub-canopy snow depth. The effectiveness of UAV-lidar and UAV-SfM in mapping snow depth in both open and forested terrain was tested in a 2019 field campaign in the Canadian Rockies Hydrological Observatory, Alberta and at Canadian Prairie sites near Saskatoon, Saskatchewan, Canada. Only UAV-lidar could successfully measure the sub-canopy snow surface with reliable sub-canopy point coverage, and consistent error metrics (RMSE <0.17m and bias -0.03m to -0.13m). Relative to UAV-lidar, UAV-SfM did not consistently sense the sub-canopy snow surface, the interpolation needed to account for point cloud gaps introduced interpolation artefacts, and error metrics demonstrate relatively large variability (RMSE <0.33m and bias 0.08 m to -0.14m). With the demonstration of sub-canopy snow depth mapping capabilities a number of early applications are presented to showcase the ability of UAV-lidar to effectively quantify the many multiscale snow processes defining snowpack dynamics in mountain and prairie environments.Item Alum addition triggers hypoxia in an engineered pit lake(MDPI, 2022-02-26) Jessen, Gerdhard L.; Chen, Lin-Xing; Mori, Jiro F.; Colenbrander Nelson, Tara E.; Slater, Gregory F.; Lindsay, Matthew B. J.; Banfield, Jillian F.; Warren, Lesley A.Here, we examine the geobiological response to a whole-lake alum (aluminum sulfate) treatment (2016) of Base Mine Lake (BML), the first pilot-scale pit lake established in the Alberta oil sands region. The rationale for trialing this management amendment was based on its successful use to reduce internal phosphorus loading to eutrophying lakes. Modest increases in water cap epilimnetic oxygen concentrations, associated with increased Secchi depths and chlorophyll-a concentrations, were co-incident with anoxic waters immediately above the fluid fine tailings (FFT) layer post alum. Decreased water cap nitrate and detectable sulfide concentrations, as well as increased hypolimnetic phospholipid fatty acid abundances, signaled greater anaerobic heterotrophic activity. Shifts in microbial community to groups associated with greater organic carbon degradation (i.e., SAR11-LD12 subclade) and the SRB group Desulfuromonodales emerged post alum and the loss of specialist groups associated with carbon-limited, ammonia-rich restricted niches (i.e., MBAE14) also occurred. Alum treatment resulted in additional oxygen consumption associated with increased autochthonous carbon production, watercap anoxia and sulfide generation, which further exacerbate oxygen consumption associated with on-going FFT mobilized reductants. The results illustrate the importance of understanding the broader biogeochemical implications of adaptive management interventions to avoid unanticipated outcomes that pose greater risks and improve tailings reclamation for oil sands operations and, more broadly, the global mining sector.Item An ecological quantification of the relationships between water, sanitation and infant, child, and maternal mortality(Environmental Health, 2012) Cheng, June J.; Schuster Wallace, Corinne; Watt, Susan; Newbold, Bruce; Mente, AndrewBackground: Water and sanitation access are known to be related to newborn, child, and maternal health. Our study attempts to quantify these relationships globally using country-level data: How much does improving access to water and sanitation influence infant, child, and maternal mortality? Methods: Data for 193 countries were abstracted from global databases (World Bank, WHO, and UNICEF). Linear regression was used for the outcomes of under-five mortality rate and infant mortality rate (IMR). These results are presented as events per 1000 live births. Ordinal logistic regression was used to compute odds ratios for the outcome of maternal mortality ratio (MMR). Results: Under-five mortality rate decreased by 1.17 (95%CI 1.08-1.26) deaths per 1000,p< 0.001, for every quartile increase in population water access after adjustments for confounders. There was a similar relationship between quartile increase of sanitation access and under-five mortality rate, with a decrease of 1.66 (95%CI 1.11-1.32) deaths per 1000,p<0.001. Improved water access was also related to IMR, with the IMR decreasing by 1.14 (95%CI 1.05-1.23) deaths per 1000,p< 0.001, with increasing quartile of access to improved water source. The significance of this relationship was retained with quartile improvement in sanitation access, where the decrease in IMR was 1.66 (95%CI 1.11-1.32) deaths per 1000,p< 0.001. The estimated odds ratio that increased quartile of water access was significantly associated with increased quartile of MMR was 0.58 (95%CI 0.39-0.86),p= 0.008. The corresponding odds ratio for sanitation was 0.52 (95%CI 0.32-0.85),p= 0.009, both suggesting that better water and sanitation were associated with decreased MMR. Conclusions: Our analyses suggest that access to water and sanitation independently contribute to child and maternal mortality outcomes. If the world is to seriously address the Millennium Development Goals of reducing child and maternal mortality, then improved water and sanitation accesses are key strategies.Item An approach to complex texts in multiple documents(Digital Studies in the Humanities, 2022) Robinson, Peter M. W.This article describes an approach to the treatment of texts in complex large textual traditions. Editors are interested in the text as it appears line-by-line in each document, and in how the versions of the text differ from document to document. It is useful to define a text as the record of an act of communication, inscribed in a document: thus, the instance of the act of communication we identify as Geoffrey Chaucer’s Canterbury Tales, as it appears in the Hengwrt manuscript. In this view, every text has a dual aspect: it is both the words as they are inscribed in a particular document, and as they constitute an act of communication and its parts. This presents challenges for scholars who wish to record both aspects. In encoding implementations, these two aspects are commonly treated as ‘overlapping hierarchies’. However, the ‘overlapping hierarchy’ model does not deal with cases where text segments are not contiguous in either aspect and cannot overlap cleanly. To meet these cases, the Textual Communities project developed an architecture in which the two aspects are represented as distinct and independent hierarchies (trees), with text segments referenced to nodes on each tree. The linking of text segments to the two trees is managed by a JSON database, accessed through transcription and collation tools presented in a Web interface. Textual Communities does not implement the whole of this architecture in terms of validation, ingestion, and processing. Full exploration and implementation of the architecture here described are challenges for future scholars.Item Aqueous vanadate removal by iron(II)-bearing phases under anoxic conditions(American Chemical Society (ACS) Publications, 2020-03-06) Vessey, Colton; Lindsay, Matthew B. J.Vanadium contamination is a growing environmental hazard worldwide. Aqueous vanadate (HxVVO4(3−x)− (aq)) concentrations are often controlled by surface complexation with metal (oxyhydr)oxides in oxic environments. However, the geochemical behaviour of this toxic redox sensitive oxyanion in anoxic environments is poorly constrained. Here we describe results of batch experiments to determine kinetics and mechanisms of aqueous H2VVO4− (100 μM) removal under anoxic conditions in suspensions (2.0 g L−1) of magnetite, siderite, pyrite, and mackinawite. We present results of parallel experiments using ferrihydrite (2.0 g L−1) and Fe2+(aq) (200 μM) for comparison. Siderite and mackinawite reached near complete removal (46 µmol g−1) of aqueous vanadate after 3 h and kinetic rates were generally consistent with ferrihydrite. Whereas magnetite removed 18 µmol g−1 of aqueous vanadate after 48 h and uptake by pyrite was limited. Uptake by Fe2+(aq) was observed after 8 h, concomitant with precipitation of secondary Fe phases. X ray absorption spectroscopy revealed V(V) reduction to V(IV) and formation of bidentate corner-sharing surface complexes on magnetite and siderite, and with Fe2+(aq) reaction products. These data also suggest that V(IV) is incorporated into the mackinawite structure. Overall, we demonstrate that Fe(II)-bearing phases can promote aqueous vanadate attenuation and, therefore, limit dissolved V concentrations in anoxic environments.Item Aqueous- and solid-phase molybdenum geochemistry of oil sands fluid petroleum coke deposits, Alberta, Canada(Elsevier, 2018-11-12) Robertson, Jared M.; Nesbitt, Jake A.; Lindsay, Matthew B. J.Fluid petroleum coke generated at oil sands operations in the Athabasca Oil Sands Region of northern Alberta, Canada, contains elevated concentrations of molybdenum (Mo) and other metals including nickel (Ni) and vanadium (V). Solid-phase Mo concentrations in fluid petroleum coke are typically 10 to 100 times lower than V and Ni, yet dissolved Mo concentrations in associated pore waters are often comparable with these metals. We collected pore water and solids from fluid petroleum coke deposits in the AOSR to examine geochemical controls on Mo mobility. Dissolved Mo concentrations increased with depth below the water table, reaching maxima of 1.4 to 2.2 mg L-1, within a mixing zone between slightly acidic and oxic meteoric water and mildly alkaline and anoxic oil sands process-affected water (OSPW). Dissolved Mo concentrations decreased slightly with depth below the mixing zone. X-ray absorption spectroscopy revealed that Mo(VI) and Mo(IV) species were present in coke solids. The Mo(VI) occurred as tetrahedrally coordinated MoO42- adsorbed via inner- and outer-sphere complexation, and was coordinated in an environment similar to Fe-(hydr)oxide surface complexes. The OSPW likely promoted desorption of outer-sphere Mo(VI) complexes, resulting in higher dissolved Mo concentrations in the mixing zone. The principal Mo(IV) species was MoS2, which originated as a catalyst added upstream of the fluid coking process. Although MoS2 is likely stable under anoxic conditions below the mixing zone, oxidative weathering in the presence of meteoric water may promote long-term Mo release.Item Assessing the oxidation states and structural stability of the Ce analogue of brannerite(Wiley, 2017) Aluri, Esther Rani; Bachiu, Lisa; Grosvenor, Andrew; Forbes, Scott; Greedan, JohnThe Ce‐containing analogue of brannerite (ie, UTi2O6) was previously considered to be stoichio- metric (ie, CeTi2O6); however, it has recently been determined that the material is O deficient. This oxygen‐deficient material has been suggested to be charged balanced by the presence of a minor concentration of Ce3+ or by the A‐site being cation deficient with the Ce oxidation state being 4+. A variety of Ti‐containing oxides (including brannerite) have been investigated as potential nuclear wasteforms, and it is necessary to understand the electronic structure of a proposed nuclear wasteform material as well as how the structure responds to radiation from incorporated waste elements. The radiation resistance of a material can be simulated by ion implantation. The objective of this study was to confirm the Ce oxidation state in the cation‐ and oxygen‐deficient material (ie, Ce0.94Ti2O6 − δ) and to determine how radiation damage affects this material. X‐ray photoelectron spectroscopy (XPS) and X‐ray absorption near‐edge spectros- copy were used to study Ce0.94Ti2O6 − δ before and after being implanted with 2 MeV Au− ions. Analysis of the Ce 3d XPS spectra from the as‐synthesized samples by using a previously developed fitting method has unequivocally shown that Ce adopts both 4+ (major) and 3+ (minor) oxidation states, which was confirmed by examination of magnetic susceptibility data. Analysis of XPS and X‐ray absorption near‐edge spectroscopy spectra from ion‐implanted materials showed that both Ce and Ti were reduced because of radiation damage and that the local coordination environments of the cations are greatly affected by radiation damage.Item Beaver dam capacity of Canada’s boreal plain in response to environmental change(Springer Nature, 2020) Stoll, Nichole-Lynn; Westbrook, CherieEnvironmental changes are altering the water cycle of Canada’s boreal plain. Beaver dams are well known for increasing water storage and slowing flow through stream networks. For these reasons beavers are increasingly being included in climate change adaptation strategies. But, little work focuses on how environmental changes will affect dam building capacity along stream networks. Here we estimate the capacity of the stream network in Riding Mountain National Park, Manitoba, Canada to support beaver dams under changing environmental conditions using a modelling approach. We show that at capacity, the park’s stream network can support 24,690 beaver dams and hold between 8.2 and 12.8 million m3 of water in beaver ponds. Between 1991 and 2016 the park’s vegetation composition shifted to less preferred beaver forage, which led to a 13% decrease in maximum dam capacity. We also found that dam capacity is sensitive to the size of regularly-occurring floods— doubling the 2-year flood reduces the park’s dam capacity by 21%. The results show that the potential for beaver to offset some expected climatic-induced changes to the boreal water cycle is more complex than previously thought, as there is a feedback wherein dam capacity can be reduced by changing environmental conditions.Item Bellerophontid molluscs in the Grimsby Formation (Llandovery, lower Silurian), Hamilton, Ontario, Canada and their paleoecological and taphonomic implications(Canadian Science Publishing, 2024-08-01) Pratt, Brian R.; Hopkins, Graeme J.; Hopkins, Richard J.Specimens of a small bellerophontid mollusc, considered conspecific with Planorbis bilobatus Conrad 1839 from coeval strata in New York State, were recovered from the Grimsby Formation (lower Llandovery, lower Silurian), exposed in the Niagara Escarpment of western Hamilton, Ontario. Because Conrad’s species name is pre-occupied and is a secondary homonym, the new material is assigned to Tritonophon grimsbyensis n. sp. As Conrad’s original specimens are lost and where he collected them is unknown, a neotype from the Grimsby Formation is designated. These bellerophonts are preserved as casts on the soles of thin, fine-grained, sandstone beds interbedded with shale. These beds are probably tempestites Most are juvenile forms oriented on their sides, but in some beds adults with a widely expanded aperture are oriented aperture-down. Some specimens exhibit a V-shaped sinus on the median lobe, which is rarely preserved in Silurian examples. The aperture-down orientation suggests that this was the stable position during gentle wave action as well as probably their life position. Beds containing only juveniles may be evidence that the bellerophonts occasionally experienced a population boom but then were killed off during the storm event. Fine-grained sandstone fills the shell interiors, likely emplaced during wave-induced agitation. However, the shell walls are cast in mudstone, indicating that they dissolved during shallow burial and mud was pumped into the moulds. This may have been aided by episodic ground motion due to earthquakes that mobilized the adjacent sediment.Item Benchmarking multiphysics software for mantle convection(Elsevier, 2021-09) Trim, Sean; Butler, Samuel; Spiteri, RaymondNumerical simulations are a highly valuable tool for improving our understanding of mantle dynamics. COMSOL Multiphysics® is a commercial software suite designed to numerically model experiments featuring multiple branches of physics. This modeling approach applies to mantle convection, which can be viewed as a combination of fluid dynamics and thermodynamics. COMSOL® is of interest to the geoscience community due to its ease of use compared to other available codes, and it has been used in previous mantle convection studies. However, COMSOL® has not been extensively benchmarked for mantle convection. In this study, we confirm the accuracy of COMSOL® against several established benchmarks pertaining to a variety mantle convection features and geometries. Overall, we find reasonable agreement between the results from COMSOL® and reported benchmark data. This study may also serve the geoscience community as a guide for using COMSOL® to model mantle convection.Item Bounds on 𝑎_𝜇^(HVP,LO) using Hölder's inequalities and finite-energy QCD sum rules(Elsevier, 2024-09-26) Li, Siyuan; Steele, Tom; Ho, Jason; R-Rahaman, Raza; Williams, K.; Kleiv, RobinThis study establishes bounds on the leading-order (LO) hadronic vacuum polarization (HVP) contribution to the anomalous magnetic moment of the muon (𝑎_𝜇^(HVP,LO), 𝑎𝜇 = (𝑔 − 2)𝜇∕2) by using Hölder’s inequality and related inequalities in Finite-Energy QCD sum rules. Considering contributions from light quarks (𝑢, 𝑑, 𝑠) up to five-loop order in perturbation theory within the chiral limit, leading-order light-quark mass corrections, next-to-leading order for dimension-four QCD condensates, and leading-order for dimension-six QCD condensates, the study finds QCD lower and upper bounds as (657.0 ± 34.8) × 10−10 ≤ 𝑎_𝜇^(HVP,LO) ≤ (788.4 ± 41.8) × 10−10.Item Builder Borders on Aboriginal Lands(2019)During the nineteenth and early twentieth centuries, the United States and Canada expended significant effort demarcating and enforcing their shared border. The surveying process began in the east, transitioned to the Pacific Coast, and concluded along the Great Plains. For much of the nineteenth century, both Britain (later Canada) and the United States claimed far more territory than they controlled in practice. Marking the border proved easier than enforcing it. Both countries relied on a wide assortment of personnel to enforce their divide, including those drawn from customs, immigration, Indian Affairs, the North West Mounted Police, military, and local police forces. The reliance on such a wide assortment of independent agencies led to infighting, confusion, and widespread inconsistencies. Many of these agencies had explicit mandates that differed from one another and, for some, border control represented only a portion of their broader duties. The geographic distribution of each of these departments, moreover, meant that the border looked quite different in each region. As these departments grew and shrank, the border changed with them. In a practical sense, the border represented a wall of uneven heights. Time period, geographic location, the zealousness of the local agents, and the demography of the region all impacted what the border looked like. Racial prohibitions towards Chinese immigration and the distinct legal status of Indigenous peoples added an additional layer of complexity. The Sioux, Nez Perce, Coast Salish, Blackfoot, Cree, Métis, Chinese, African Americans, and Europeans all experienced different borders from one another in both a legal and practical sense. The Building Borders on Aboriginal Lands Project provides a quantitative and geospatial backbone to understand how Canada and the United States exerted control over their shared border. The project maps federal power and engagement between 1860 and 1924 as people were hired and fired and as posts were built and fell into disrepair. The project consists of personnel and post records for each of the major agencies who patrolled the border as well as their patrol routes where available. Finally, this project digitized the survey records for the Pacific Coast. The border survey process was not possible without the contributions of hundreds of Indigenous guides, packers, and transporters, many of whom appeared in the special paylist section of that report.Item Chemical mass transport between fluid fine tailings and the overlying water cover of an oil sands end pit lake(American Geophysical Union, 2017-05-17) Dompierre, Kathryn A.; Barbour, S. Lee; North, Rebecca L.; Carey, Sean K.; Lindsay, Matthew B. J.Fluid fine tailings (FFT) are a principal by-product of the bitumen extraction process at oil sands mines. Base Mine Lake (BML)—the first full-scale demonstration oil sands end pit lake (EPL)—contains approximately 1.9 3 108 m^3 of FFT stored under a water cover within a decommissioned mine pit. Chemical mass transfer from the FFT to the water cover can occur via two key processes: (1) advection-dispersion driven by tailings settlement; and (2) FFT disturbance due to fluid movement in the water cover. Dissolved chloride (Cl) was used to evaluate the water cover mass balance and to track mass transport within the underlying FFT based on field sampling and numerical modeling. Results indicated that FFT was the dominant Cl source to the water cover and that the FFT is exhibiting a transient advection-dispersion mass transport regime with intermittent disturbance near the FFT-water interface. The advective pore water flux was estimated by the mass balance to be 0.002 m^3 m^-2 d^-1, which represents 0.73 m of FFT settlement per year. However, the FFT pore water Cl concentrations and corresponding mass transport simulations indicated that advection rates and disturbance depths vary between sample locations. The disturbance depth was estimated to vary with location between 0.75 and 0.95 m. This investigation provides valuable insight for assessing the geochemical evolution of the water cover and performance of EPLs as an oil sands reclamation strategy.Item Chitosan Biocomposites with Variable Cross-Linking and Copper-Doping for Enhanced Phosphate Removal(MDPI, 2024-01-16) Udoetok, Inimfon A.; Karoyo, Abdalla H.; Mohamed, Mohamed H.; Wilson, Lee D.The fabrication of chitosan (CH) biocomposite beads with variable copper (Cu2+) ion doping was achieved with a glutaraldehyde cross-linker (CL) through three distinct methods: (1) formation of CH beads was followed by imbibition of Cu(II) ions (CH-b-Cu) without CL; (2) cross-linking of the CH beads, followed by imbibition of Cu(II) ions (CH-b-CL-Cu); and (3) cross-linking of pristine CH, followed by bead formation with Cu(II) imbibing onto the beads (CH-CL-b-Cu). The biocomposites (CH-b-Cu, CH-b-CL-Cu, and CH-CL-b-Cu) were characterized via spectroscopy (FTIR, 13C solid NMR, XPS), SEM, TGA, equilibrium solvent swelling methods, and phosphate adsorption isotherms. The results reveal variable cross-linking and Cu(II) doping of the CH beads, in accordance with the step-wise design strategy. CH-CL-b-Cu exhibited the greatest pillaring of chitosan fibrils with greater cross-linking, along with low Cu(II) loading, reduced solvent swelling, and attenuated uptake of phosphate dianions. Equilibrium and kinetic uptake results at pH 8.5 and 295 K reveal that the non-CL Cu-imbibed beads (CH-b-Cu) display the highest affinity for phosphate (Qm = 133 ± 45 mg/g), in agreement with the highest loading of Cu(II) and enhanced water swelling. Regeneration studies demonstrated the sustainability and cost-effectiveness of Cu-imbibed chitosan beads for controlled phosphate removal, whilst maintaining over 80% regenerability across several adsorption–desorption cycles. This study offers a facile synthetic approach for controlled Cu2+ ion doping onto chitosan-based beads, enabling tailored phosphate oxyanion uptake from aqueous media by employing a sustainable polysaccharide biocomposite adsorbent for water remediation by mitigation of eutrophication.