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Storage and utilization of CO2 in ready-mix concrete using CO2-loaded aqueous inorganic solvent
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Applied Science in Process Systems Engineering, University of Regina. xvi, 145 p.Cement production is a significant contributor to CO2 emissions, prompting the
need for innovative approaches to mitigate its environmental impact. This work is focused
on developing a workable process that can capture CO2 emitted by cement production
and eventually store the captured CO2 in concrete to accelerate concrete curing. Potassium
glycinate (K-glycinate), an environmentally friendly aqueous inorganic solvent was
employed for this work. Firstly, 6M aqueous K-glycinate solvent prepared from glycine
and potassium hydroxide was loaded with CO2 at 60℃ to produce CO2-loaded Kglycinate.
Prior to being allowed to cool to room temperature (24±2 ℃), the solvent was
diluted (dilution factor 1.5) with distilled water to eliminate any precipitation.
Secondly, the CO2-loaded K-glycinate was utilized in two different batches of
concrete. The first batch of concrete which is identified as concrete batch I consisted of
sand, cement, rock and water. On the other hand, the second batch of concrete which is
identified as concrete batch II consisted of additional materials which were admixtures
(poly 980 and micro air) and fly ash. Nine different concrete mixtures were produced for
this work. Four for the concrete batch I and five for the concrete batch II. The concrete
mix for the concrete batch I were Baseline concrete I, 19% carbonated K-glycinate
concrete I, 27% carbonated K-glycinate concrete I and 37% carbonated K-glycinate I.
The baseline concrete I composed of only cement, sand, water and rock. The carbonated
K-glycinate concretes I were produced by replacing a fraction of water with CO2-loaded
K-glycinate. For instance, the 19% carbonated K-glycinate concrete I was produced by
replacing the 19% of the mass of water in the Baseline concrete I with CO2-loaded Kglycinate.
The concrete batch II consisted of Baseline concrete II, 6% carbonated Kglycinate
concrete II, 9% carbonated K-glycinate concrete II, 20% carbonated Kglycinate
II, and 32% carbonated K-glycinate concrete II. The baseline concrete II was
produced by adding additional materials which were fly ash and admixtures (poly 980
and micro air) to the cement, sand, rock and water. A fraction of the water in the baseline
concrete II was replaced with CO2-loaded K-glycinate to form the carbonated K-glycinate
concretes II.
The performance of the concrete was evaluated using compressive strength,
curing time, CO2 storage capacity as well as other properties such as slump, air content
and density of the concrete. The CaCO3 and other compounds formed in the concrete as
well as the CO2 storage capacity of the concrete was analysed using XRD and TGA/DTA
respectively. Physical properties of the CO2-loaded K-glycinate – water mixture such as
viscosity, surface tension, capillarity and contact angle were estimated to investigate their
effect on the rate of curing and CO2 storage capacity of the concrete. The 19% carbonated
K-glycinate concrete I and the 6% carbonated K-glycinate concrete II had the highest
performance in concrete batch I and batch II respectively. Among the concrete batch I,
the 19% carbonated K-glycinate concrete I had the shortest curing time and highest
compressive strength indicating the largest amount of CO2 uptake. Similar performance
was observed for the 6% carbonated K-glycinate concrete II for the concrete batch II.
The XRD profiles for concrete batch I and II revealed the presence of CaCO3 and
CaMg(CO3)2, which are responsible for concrete's strength. The TGA/DTA profiles for
the concrete confirmed that CO2 is permanently stored in the concrete due to the
magnitude of the temperatures (600 - 930℃) that was required to remove the CO2 from
the concrete.
The properties of the carbonated K-glycinate – water mixture used for the concrete
revealed that lower viscosity, higher capillarity, higher surface tension and contact angle
favour concrete performance.Studentye
Can children detect grooming tactics?
No full textA Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Bachelor of Arts (Honours) in Psychology, University of Regina. 73 p.This study examined whether school-aged children (N = 524) are able to perceive grooming tactics and behaviours in adults. To do this, children read two short, vague stories containing elements of adult grooming behaviour. The stories were about a girl or boy leaving to help a custodian or coach. The child in the story went to either a private or public place with the adult for the first time or has helped the adult before and will return or not return from the secondary setting in the story. After reading the story, the child was asked follow-up questions to determine their perceptions. It was hypothesized that older children would have higher rates of detection than younger children and they would have higher rates of detection in the Return, Multiple, and Private conditions. No significant differences were found between the three story conditions, but older children were found to detect grooming at higher levels than younger children. These findings provide evidence as to why young children may be more likely to be victimized by such methods
Psychometric evaluation of the COVID stress scales in older adults and the impact of ageism and pain on COVID-related stress
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Science in Clinical Psychology, University of Regina. xii, 180 p.The literature has documented strong manifestations of ageism stemming from the
COVID-19 pandemic (e.g., social media posts suggesting that older adults’ deaths from
COVID-19 are less tragic than younger individuals, beliefs that public health restrictions
should only target older persons). Additionally, pain is highly prevalent among older
adults and often limits mobility, which can exacerbate stress and pain severity during
pandemics in which public health measures promote physical distancing or impose
restrictions that reduce access to pain treatment. Prior to the COVID-19 pandemic, both
ageism and pain have been identified as predictors of adverse health outcomes in older
adults (e.g., stress, anxiety, functional impairment). However, the influence of ageism
and pain on stress specifically within the context of COVID-19 had not been investigated
among older adults. The COVID Stress Scales (CSS) is a widely used measure designed
to measure multidimensional stress reactions related to the COVID-19 pandemic (i.e.,
danger and contamination fears; socioeconomic consequences; xenophobia; compulsive
checking and reassurance seeking; traumatic stress symptoms). Though the CSS has been
extensively validated across cultures, its psychometric properties had not been confirmed
in an older adult sample. Moreover, item response theory (IRT) analysis was needed to
examine its properties at the item level with older adults. This study was aimed at
addressing these gaps by validating the CSS in older adults and examining how ageism
and pain impact COVID-related stress responses measured by the CSS in this population.
A population-representative sample of 486 Canadian and American older adults aged ≥65
years completed an online Qualtrics survey in January 2024. Participants completed
measures of COVID-related stress, pain, ageism, and social desirability. As expected,
results indicate that the CSS demonstrates robust psychometric properties and has a
defensible five- and six-factor model structure, though its six-factor model provides the
most optimal measurement of COVID-related stress in the older adult population. All
items on the CSS were also found to adequately differentiate between older adults with
lower and higher levels of COVID-related stress, though some items were identified as
having lower overall discriminatory efficacy. Furthermore, as expected, the extent to
which older adults reported experiencing ageism was positively associated with both the
combined domains of COVID-related stress and each individual domain of the CSS. Pain
was also associated with the combined domains of COVID-related stress and several
individual CSS domains (i.e., fear of danger; fear of socioeconomic consequences;
traumatic stress symptoms; compulsive checking and reassurance seeking). Findings
from this investigation highlight factors that are related to increased pandemic-related
stress in older adults. This evidence can guide future treatment strategies for healthcare
providers working with the older adult population in response to future waves of COVID-
19, or during other pandemics or infectious outbreaks. Additionally, this investigation
confirms that the CSS is a highly reliable and valid measure which can be used by
clinicians or researchers in future studies to assess pandemic-related stress experienced
by older adults within the context of COVID-19 or future pandemics and determine
appropriate interventions.
Keywords: ageism, COVID Stress Scales, older adults, pain, pandemic-related
stressStudentye
Impacts of hydrologic management on the eutrophication of shallow lakes in an intensive agricultural landscape (Saskatchewan, Canada)
No full text1. Hydrologic management of shallow lakes is often undertaken to prevent fluctua-
tions in lake level, and to ensure sufficient water volume for economic, domestic,
and recreational uses, but there is inconsistent evidence of whether lake-level sta-
bilisation through hydrological management promotes or hinders eutrophication.
2. Here we used multi-proxy paleolimnological assessments of water quality (sedi-
mentary carbon, nitrogen, total phosphorus, fossil pigments), and zooplankton
community ecology (fossil Cladocera assemblages), combined with Landsat-
derived estimates of lake surface area in two shallow eutrophic lakes, in the
Prairies of southern Saskatchewan, Canada, to quantify how 8 decades of con-
trasting hydrological management strategies (continuous or intermittent) affect
primary production and phytoplankton composition.
3. Analysis revealed that irregular hydrological management of Pelican Lake led to
sharp increases in primary production concomitant with lake-level decline. In
contrast, continuously managed Buffalo Pound Lake, a drinking water reservoir
for regional cities, exhibited slow, persistent eutrophication over decades despite
active regulation of water levels. In both lakes, strong correlations of δ 15N val-
ues with pigments from diazotrophic cyanobacteria (canthaxanthin) showed that
N2-fixation increased during eutrophication irrespective of the timing of change.
Finally, variation in fossil cladoceran density and composition reflected changes
in pelagic and littoral habitats (e.g., reduced macrophyte cover) due to changes in
both lake level and water quality.
4. Basin comparison shows that while hydrologic management can moderate water
quality degradation due to lake-level change, it does not prevent eutrophication
when nutrient influx remains high.
5. Given that regional water availability is forecast to decline in coming decades, we
anticipate that continued hydrological management will be unavoidable and will
be unable to improve water quality unless nutrient influx is also controlled.Natural Sciences and Engineering
Research Council of Canad
A serving of empathy
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Fine Arts in Visual Arts, University of Regina. viii, 40 p.A Serving of Empathy, my MFA graduating exhibition at the Fifth Parallel Gallery at the University of Regina (June 10–21, 2024), consists of two bodies of work. Potent Moments (2024) is a collection of sixteen ceramic plates exploring the lives of young people at moments of crisis, transition, and suspense. Fragments of Memory (2022) is a suite of ten conjoined ceramic plates that depict my mother’s train journey from Regina to Victoria in 1950 when she was fifteen. The plates are displayed on the gallery walls at eye-level. In addition, “Carousel of Innocence,” an interactive work set on a low plinth in the centre of the gallery, provides a moment of pleasure amid the tension of the surrounding pieces.
Potent Moments are visual narratives painted on modified ceramic plates. Thin slabs are added to the surface while the wheel-thrown clay is soft. They are torn to produce shallow ragged openings for the painted scenes. The scenes are mostly private moments that my omniscient visual narrator invades to reveal hidden truths and to generate empathy. These paintings realize the mental images I had when I heard stories, and the mental images I created over the years when reviving the original stories.
Fragments of Memory is a suite of five ceramic artworks that reconstruct my memory of my mother’s remembered experience. This artwork is about the relationship between narrative content, memory, imagination, and perceptual position; about how we try to inhabit and understand the experiences of others through imaginative means. Using conjoined ceramic forms, painted images, and ceramic shards, I create artworks that not only reconstruct what can be remembered but also describe the process of remembering.
Keywords: ceramics, clay, plates, stories, heterotopias, omniscient viewer, omniscient narratorStudentye
Advanced approaches to ruin probability and novel extensions of Hoeffding Inequalities in insurance mathematics
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Statistics, University of Regina. x, 100 p.In the ever-evolving domain of risk theory, understanding the intricate relationships
between ruin probability, risk management, and the complexities of financial
mathematics has never been more imperative. This thesis provides a comprehensive
exploration into the nuances of ruin probability and its critical importance in
the modern financial landscape. By delving deep into the mathematical intricacies,
the study generalizes Hoeffding inequalities for random variables belonging to an extended
acceptable class. This generalization is pivotal, leading to the establishment
of the minimum premium rate. The thesis achieves this through the construction
of an exponentially decaying upper bound for the ruin probability, built upon the
foundational concepts of Hoeffding’s generalization.
Furthermore, the research draws inspiration from seminal works in the field, paying
homage to pioneers such as Filip Lundberg and Harald Cramér. While the contributions
of these stalwarts have been immense, the contemporary challenges of the
financial world demand a fresh perspective and novel methodologies. To this end,
the study encapsulates the interdependencies between various financial elements, the
importance of understanding negatively dependent or extended acceptable random
variables, and the criticality of large deviation inequalities.
Moreover, the synthesis of past methodologies with the latest techniques has enabled
a more comprehensive understanding of exponentially decaying inequalities.
The thesis provides a thorough literature review, chronicling the evolution of thought
in the realm of risk theory, bridging the gap between historical foundations and current
advancements.
In conclusion, this thesis stands as a testament to the importance of rigorous
mathematical frameworks in understanding and navigating the complexities of risk
management in today’s volatile financial ecosystem.Studentye
Develop innovative methodology to optimally fill in missing values and predict progression on multiple sclerosis
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Industrial Systems Engineering, University of Regina. xxi, 198 p.Applying Machine Learning (ML) to predict and track Multiple Sclerosis (MS) progression is a significant advancement in medical research, with the potential to enhance patient outcomes. Accurate MS prediction enables personalized treatment, timely interventions, and improved quality of life by slowing disease progression and preventing complications. This research aims to deepen our understanding of MS by developing ML models and comprehensive risk assessments to support early prognosis, guide treatment strategies, and reduce disease impact.
A major challenge in medical research, especially in predicting MS progression, is effectively managing missing data in MS datasets. This study introduces an innovative sequential Multi-Imputation (MI) bootstrapping method to address the challenge of missing data in MS datasets. Initially, several ML algorithms, including k-Nearest Neighbors (kNN), Random Forest (RF), and Multilayer Perceptron (MLP), are evaluated for imputation efficiency. RF and MLP perform best, achieving overall accuracies of 92% and 91.5%, respectively, in handling missing data more accurately than other models. Given the effectiveness of RF and MLP in capturing complex patterns in data, these models are selected for further development.
The next step applies Multi-Imputation (MI) bootstrapping in a sequential manner, prioritizing features based on the strength of their relationships, as determined by Pearson correlation analysis. This statistical technique identifies features with the highest correlations, ensuring that attributes with stronger relationships with other attributes, are imputed first. These imputed features then inform the next imputation in the sequence, cooperating with the subsequent ranked feature in the order. Bootstrapping, a resampling technique that involves replacement, creates multiple training datasets by repeatedly sampling from the original data, enhancing the robustness of the imputation process.
The proposed sequential imputation method integrates bootstrapping with RF, achieving an accuracy up to 97 % for MS datasets. This iterative approach effectively imputes missing data attributes while accounting for feature significance and relationships. The results also show that prioritizing normalization improves scaling impact, and that the significant features in the original dataset are crucial to the accuracy of MS missing data estimations. These findings provide valuable insights into effective imputation techniques for MS prediction, offering a foundation for future improvements in handling missing data in specific datasets.
In addition, this study solves the common overfitting problem caused by data imbalance through a comprehensive method combining feature extraction, undersampling, Synthetic Minority Oversampling Technique (SMOTE) and optimal threshold method. Support Vector Machine (SVM), Logistic Regression (LogR), Decision Tree (DT), RF, KNN, MLP and Naive Bayes (NB) are used for prognostic modeling while examining risk factor associations.
The results showed that the proposed method prevented overfitting during model training and developed a robust MS progression prognosis model, achieving a prediction accuracy of 98%, particularly for SVM and MLP
The methods proposed in this dissertation can help develop more concise guidelines for the medical research communities and improve their evaluation processes. These innovations not only advance prognostic analysis in MS, but also pave the way for future research focused on optimizing patient outcomes and treatment strategies.Studentye
Recruiting and Engaging Heterosexual-Identified Men Who have Sex with Men: A Brief Report of Considerations for Sex Researchers
No full textHeterosexual-identified men who have sex with men (H-MSM) are a unique population difficult to identify
and recruit for research and practice. Yet, engaging H-MSM remains a top research priority to learn more
about this population’s health needs. A scoping review was conducted to develop a stronger under-
standing of recruitment patterns involving H-MSM in research. The search and screening procedures
yielded 160 total articles included in the present study. Most studies relied on venue-based and internet-
based recruitment strategies. Thematic analysis was then used to identify three themes. Locations of
H-MSM’s sexual encounters related to where sex researchers may recruit participants; sociocultural
backgrounds of H-MSM related to important characteristics researchers should acknowledge and con-
sider when working with H-MSM; and engagement with health services related to how H-MSM interact
with or avoid HIV/STI testing and treatment and other public health services. Findings suggest H-MSM
have sex with other men in a variety of venues (e.g. bathhouses, saunas) but tend to avoid gay-centric
venues. H-MSM also are diverse, and these unique identities should be accounted for when engaging
them. Finally, H-MSM are less likely to access healthcare services than other MSM, highlighting the need
for targeted advertisements and interventions specific for H-MSM.This project was funded by an Insight Grant from the Social Sciences and
Humanities Research Council of Canada [SSHRC #435-2022-0887]
Promote the development of novel post-combustion CO2 capture technology towards practical and feasible: Design and assessment of solvents and process configurations
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Process Systems Engineering, University of Regina. xxi, 199 p.This thesis focuses on developing novel CO2 capture processes that encompasses
both CO2 absorption and solvent regeneration process. The work adhered to the guiding
principle “Simplify complex system engineering towards practicality and feasibility”.
This research aims not only to explore the enhancement of the state of art technologies
in the CO2 capture industry but also to improve the potential for practical operations in
pilot and industrial scale, ensuring it meets the general level of practical industrial
application. Several experimental and simulation tasks have been accomplished in labs,
including solvent screening tests, process configuration design, simulation studies, and
bench-scale pilot plant experiments. In this research, the primary emphasis is on the
amine-based post-combustion carbon capture process. This research addresses three
common concerns regarding amine process from three different perspectives: (i)
Introducing blended solvents into the process; (ii) Using conventional MEA solvent
with catalyst via a novel “easy-to-use” operating method; (iii) Process integration and
optimization for conventional MEA process. The ultimate goal is to reduce the
operating costs from the solvent and energy demand.
Due to solid acid catalyst’s maturity and promising performance in the amine
regeneration process, HZSM-5 was considered the rate promoter in aqueous amine
systems. Prior to designing a practical catalytic process, studying the solvent can help
understand its performance in the CO2 absorption and desorption process. Therefore,
various aqueous amine-based solvents were initially screened in batch-scale CO2
absorption and desorption experiments in terms of initial absorption rate, initial
desorption rate and equilibrium solubility of CO2.
Designing a practical catalytic process aims to ensure efficient and effective
operation. In other words, the redesigned catalytic process should be user-friendly and
offer enhanced catalyst efficiency. This work details the progress made during the
design phase and illustrates the final schematic of the operational unit, which fulfills
the target requirements.
Furthermore, several novel blank amine-based process configurations were
developed to advance the industrial transformation of traditional technologies such as
Mechanical Vapor Recompression (MVR) technology and solvent split-flow
configurations. Based on the sensitivity and simulation feasibility study, these new
technologies are anticipated to have lower construction and equipment costs while
delivering higher operating profits. A comparative study was conducted to evaluate the
features and summarize the advantages and potential operation challenges of the novel
CCS processes proposed in this research.Studentye
Anchoring has little effect when forming first impressions of facial attractiveness
No full textFirst impressions based on facial appearance affect our behaviour towards others. Since the same face will appear different across images, over time, and so on, our impressions may not be equally weighted across exposures but are instead disproportionately influenced by earlier or later instances. Here, we followed up on previous work which identified an anchoring effect, whereby higher attractiveness ratings were given to a person after viewing naturally varying images of their face presented in descending (high-to-low), rather than ascending (low-to-high), order of attractiveness of these images. In Experiment 1 ( n = 301), we compared these ‘descending’ and ‘ascending’ conditions for unfamiliar identities by presenting six-image sequences. Although we found higher attractiveness ratings for the ‘descending’ condition, this small effect equated to only 0.22 points on a 1–7 response scale. In Experiment 2 ( n = 307), we presented these six-image sequences in a random order and found no difference in attractiveness ratings given to these randomly ordered sequences when compared with those resulting from both our ‘descending’ and ‘ascending’ conditions. Further, we failed to detect an influence of the earlier images in these random sequences on attractiveness ratings. Taken together, we found no compelling evidence that anchoring could have an effect on real-world impression formation