Synchrotron Sciences

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https://hdl.handle.net/10388/14356

With Canada's only synchrotron and the largest number of synchrotron users of any university in Canada, we are harnessing powerful imaging and analytical techniques to solve challenges in health, environment, materials science and other areas of global social and economic importance.

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Hydrogen uptake and embrittlement behavior in pipeline steels: Insights from slow strain rate testing and synchrotron micro-CT imaging
(Engineering Failure Analysis, 2025-02) Jack, Tonye; Webb, Mark Adam; Rahman, K.M. Mostafijur; Fazeli, Fateh; Szpunar, Jerzy
Hydrogen embrittlement (HE) presents a major challenge to the integrity of steel pipelines, often leading to premature failure. Traditional methods using two-dimensional (2D) analysis of damaged structures, often overlook critical features related to failure. Hence, this study investigates the hydrogen embrittlement susceptibility of two pipeline steels, X60 and X65, using a combination of mechanical testing, hydrogen diffusion and trapping studies, microstructural characterization, and synchrotron micro-computed tomography (micro-CT) imaging. The results highlight the critical role of hydrogen trapping and retention in HE, with steel microstructure significantly affecting hydrogen uptake and diffusion as well as crack nucleation and propagation. Synchrotron micro-CT imaging provided more accurate crack pattern assessments than traditional 2D methods, revealing potential misinterpretations from 2D cross-sectional analysis. This study concludes that simultaneous hydrogen ingress and mechanical loading is more damaging than pre-charging with high hydrogen concentrations, and that hydrogen retention capacity plays a greater role in embrittlement behavior than crack initiation. The failure mechanism of the hydrogen-charged steels shifted from being plasticity-based to decohesion-driven, based on the hydrogen content and retention in the steel, which is in line with the unified HELP+HEDE model.
Synchrotron X-ray imaging study on the mechanism of solids transfer to bitumen froth during oil sands flotation 1: True flotation
(Elsevier, 2025-01-18) Zhang, Hanyu; Xia, Liuyin; Zhu, Yanfei; Gasilov, Sergey; He, Iris; Ding, Xiaofan
Unwanted mineral solids in bitumen froth can lead to increased solvent usage and higher hydrocarbon loss in downstream processing, negatively impacting the cost-effectiveness and sustainability of synthetic crude oil production. Enhancing the quality of bitumen froth with fewer solids is a goal for oil sands processors. This study presents an in-situ analysis of the particle size distribution and association of solids in bitumen froth, thereby uncovering solids transport mechanisms, such as true flotation. Oil sands flotation experiments were conducted with 30% pulp density, at 50 °C and pH 8.5. The collected bitumen froth was immediately characterized using synchrotron-based X-ray imaging by a monochromatic X-ray with photon energy of 60 keV provided by 05ID-2 beamline of the BioMedical Imaging and Therapy (BMIT) facility at the Canadian Light Source (CLS). This characterization method can finish a typical CT scan with 2000 projections in less than 3 min, and thus allows for in-situ imaging of freshly prepared bitumen froth without the need for special arrangements, such as freezing. 14, 234 unwanted solids carried over into bitumen froth were visualized, 98.9 wt% of them were sand particles, which is consistent with mineral liberation analysis (MLA) results. This study introduced an innovative image segmentation technique to quantify the transfer of particles into the bitumen froth via true flotation. Statistical analysis revealed that approximately 53 wt% of sand particles were collected due to true flotation. Furthermore, the median particle size (P50) for sand particles entering froth by true flotation was determined to be 67.6 μm, significantly larger than the 30.6 μm observed for particles transferring through entrainment or entrapment.
Data-driven exploration of weak coordination microenvironment in solid-state electrolyte for safe and energy-dense batteries
(Springer Nature, 2025) Lao, Zhoujie; Tao, Kehao; Xiao, Xiao; Qu, Haotian; Wu, Xinru; Han, Zhiyuan; Gao, Runhua; Wang, Jian; Wu, Xian; Chen, An; Shi, Lei; Chang, Chengshuai; Song, Yanze; Wang, Xiangyu; Li, Jinjin; Zhu, Yanfei; Zhou, Guangmin
The unsatisfactory ionic conductivity of solid polymer electrolytes hinders their practical use as substitutes for liquid electrolytes to address safety concerns. Although various plasticizers have been introduced to improve lithium-ion conduction kinetics, the lack of microenvironment understanding impedes the rational design of high-performance polymer electrolytes. Here, we design a class of Hofmann complexes that offer continuous two-dimensional lithium-ion conduction channels with functional ligands, creating highly conductive electrolytes. Assisting with unsupervised learning, we use Climbing Image-Nudged Elastic Band simulations to screen lithium-ion conductors and screen out five potential candidates that elucidate the impact of lithium coordination environment on conduction behavior. By adjusting the covalency competition between Metal−O and Li−O bonds within Hofmann complexes, we can manipulate weak coordination environment of lithium-ion for rapid conduction kinetics. Li | |sulfurized polyacrylonitrile (SPAN) cell using solid-state polymer electrolytes with predicted Co(dimethylformamide)2Ni(CN)4 delivers an initial discharge capacity of 1264 mAh g−1 with a capacity retention of 65% after 500 cycles at 0.2 C (335 mA g−1), at 30 °C ± 3 °C. The assembled 0.6 Ah Li | |SPAN pouch cell delivers an areal discharge capacity of 3.8 mAh cm−2 at the second cycle with a solid electrolyte areal mass loading of 18.6 mg cm−2 (mass-to-capacity ratio of 4.9).
MugenNet: A Novel Combined Convolution Neural Network and Transformer Network with Application in Colonic Polyp Image Segmentation
(Sensors, 2024-11) Peng, Chen; Qian, Zhiqin; Wang, Kunyu; Zhang, Lanzhu; Luo, Qi; Bi, Zhuming; Zhang, Wenjun
Accurate polyp image segmentation is of great significance, because it can help in the detection of polyps. Convolutional neural network (CNN) is a common automatic segmentation method, but its main disadvantage is the long training time. Transformer is another method that can be adapted to the automatic segmentation method by employing a self-attention mechanism, which essentially assigns different importance weights to each piece of information, thus achieving high computational efficiency during segmentation. However, a potential drawback with Transformer is the risk of information loss. The study reported in this paper employed the well-known hybridization principle to propose a method to combine CNN and Transformer to retain the strengths of both. Specifically, this study applied this method to the early detection of colonic polyps and to implement a model called MugenNet for colonic polyp image segmentation. We conducted a comprehensive experiment to compare MugenNet with other CNN models on five publicly available datasets. An ablation experiment on MugenNet was conducted as well. The experimental results showed that MugenNet can achieve a mean Dice of 0.714 on the ETIS dataset, which is the optimal performance on this dataset compared to other models, with an inference speed of 56 FPS. The overall outcome of this study is a method to optimally combine two methods of machine learning which are complementary to each other.
Discovery of Ge2+ in quartz: Evidence from EPR/XAS experiments and DFT calculations, and implications for Ge/Si systematics
(Geochimica et Cosmochimica Acta, 2025-01) Mashkovtsev, Rudolf I.; Botis, Sanda M.; Lin, Jinru; Deevsalar, Reza; Cheung, Leo Ka Long; Wiens, Eli; Tunc, Ayetullah; Chen, Ning; Chernikov, Roman; Pan, Yuanming
The Ge/Si systematics as a biogeochemical tracer with diverse applications from paleo-climatic reconstructions to discrimination of magma sources and elucidation of Earth’s early evolution hinges on the coherent behavior of these elements in the tetravalent state. However, determination of Ge speciation in quartz and other silicate minerals is technically challenging because this element almost invariably occurs at several parts per million or lower concentrations. This contribution reports a detailed study of Ge speciation in quartz by combining single-crystal electron paramagnetic resonance spectroscopy, synchrotron X-ray absorption spectroscopy, and ab initio theoretical calculations. Our single-crystal and powder electron paramagnetic resonance spectra of artificially irradiated quartz reveal a suite of previously reported Ge electron centers (GECs) such as [GeHLi2]0 and [GeHH2]0 centers as well as a new GeHLi center. These multiply-compensated GECs in artificially irradiated quartz suggest that their precursors before irradiation involve the diamagnetic Ge2+ state. Ge K-edge X-ray absorption spectroscopic data of selected quartz samples further support the presence of Ge2+. Theoretical calculations reproduce the experimental 1H and 7Li hyperfine constants of the [GeHLi2]0 center and suggest the new GeHLi center to be a new variant of the multiply-compensated GECs with the second monovalent cation in a distant c-axis channel, again supporting the Ge2+ state. The presence of Ge2+ in sedimentary-diagenetic quartz, in particular, challenges existing thermodynamic data that Ge4+ is the only stable oxidation state in aqueous solutions under near-surface conditions. Incorporation of Ge2+ in quartz and other silicates can significantly affect Ge/Si fractionations, with important implications for their applications as a biogeochemical tracer from surficial environments to magmatic-hydrothermal systems, Earth’s core-mantle differentiation, and other planetary processes.
Unraveling chemical origins of dendrite formation in zinc-ion batteries via in situ/operando X-ray spectroscopy and imaging
(Nature Portfolio, 2024) Dai, Hongliu; Sun, Tianxiao; Zhou, Jigang; Wang, Jian; Chen, Zhangsen; Zhang, Gaixia; Sun, Shuhui
To prevent zinc (Zn) dendrite formation and improve electrochemical stability, it is essential to understand Zn dendrite growth, particularly in terms of morphology and relation with the solid electrolyte interface (SEI) film. In this study, we employ in-situ scanning transmission X-ray microscopy (STXM) and spectro-ptychography to monitor the morphology evolution of Zn dendrites and to identify their chemical composition and distribution on the Zn surface during the stripping/plating progress. Our findings reveal that in 50 mM ZnSO4, the initiation of moss/whisker dendrites is chemically controlled, while their continued growth over extended cycles is kinetically governed. The presence of a dense and stable SEI film is critical for inhibiting the formation and growth of Zn dendrites. By adding 50 mM lithium chloride (LiCl) as an electrolyte additive, we successfully construct a dense and stable SEI film composed of Li2S2O7 and Li2CO3, which significantly improves cycling performance. Moreover, the symmetric cell achieves a prolonged cycle life of up to 3900 h with the incorporation of 5% 12-crown-4 additives. This work offers a strategy for in-situ observation and analysis of Zn dendrite formation mechanisms and provides an effective approach for designing high-performance Zn-ion batteries.
Negative Charge Transfer Energy in Correlated Compounds
(Physical Society of Japan, 2024-09-13) Green, Robert J.; Sawatzky, George A.
In correlated compounds containing cations in high formal oxidation states (assigned by assuming that anions attain full valence shells), the energy of ligand to cation charge transfer can become small or even negative. This yields compounds with a high degree of covalence and can lead to a self-doping of holes into the ligand states of the valence band. Such compounds are of particular topical interest, as highly studied perovskite oxides containing trivalent nickel or tetravalent iron are negative charge transfer systems, as are nickel-containing lithium ion battery cathode materials. In this report, we review the topic of negative charge transfer energy, with an emphasis on plots and diagrams as analysis tools, in the spirit of the celebrated Tanabe–Sugano diagrams which are the focus of this Special Topics Issue.
Development of a Small-Scale Test Facility for Effectiveness Evaluation of Fixed-Bed Regenerators
(Elsevier, 2020-06-25) Krishnan, Easwaran Nampoothiry; Ramin, Hadi; Shakouri, Mohsen; Wilson, Lee D; Simonson, Carey
Fixed-bed regenerators (FBR) transfer heat (and moisture) between supply and exhaust air streams in heating, ventilating and air conditioning (HVAC) systems to reduce building energy consumption. This paper presents a new small-scale testing facility to evaluate the performance (i.e. sensible effectiveness) of FBRs for HVAC applications. The major contributions of this paper are: development of a new small-scale experimental facility and methodology for testing FBRs, quantification of uncertainties, and verification of small-scale test data over a large range of FBR design conditions. A numerical model and two well-known design correlations are used to verify the results and testing methodology. The advantages of small-scale testing are that it requires low volume of conditioned airflow, has low uncertainty, requires less exchanger material and has a low cost per test. Moreover, the small-scale testing methodology of FBR would benefit heat exchanger manufacturers to perform detailed sensitivity studies and optimize the exchanger performance over a wide range of design and operating parameters prior to the fabrication of full-scale exchangers.
X-ray absorption spectroscopy and X-ray diffraction data for molybdenum minerals and compounds
(Elsevier, 2022-09-13) Schoepfer, Valerie; Lindsay, Matthew B. J.
We report Mo K- and LIII-edge X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) data collected for 15 molybdenum minerals and compounds sourced from museum collections, mineral dealers, and chemical suppliers. The samples were finely ground and analyzed at the Canadian Light Source synchrotron (Saskatoon, Canada). The L III-edge XAS data were collected in fluorescence and total electron yield mode, while the K-edge XAS data were collected in transmission and fluorescence modes. Molybdenum L III-edge spectra cover the X-ray absorption near edge structure (XANES) region and Mo K-edge spectra cover the extended X-ray absorption fine structure (EXAFS) region. Tabulated XAS data are provided to support analysis of XAS data obtained for geological or environmental research. Furthermore, Mo K-edge EXAFS and L III-edge XANES spectra, the k3 weighted oscillatory χ(k) functions, and the Fourier-transforms in χ(R) of these K-edge data are presented graphically. Corresponding XRD data were collected as two-dimensional images against an area detector and integrated to form line scans. The data were collected at a wavelength of 0.68866 Å (18 keV) and is tabulated and presented graphically over a 0-40 °2Q range. This dataset is intended to be used as reference material for a variety of rare and common Mo phases.

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