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Saturated-unsaturated behavior of natural cohesionless soils
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 Environmental Systems Engineering, University of Regina. xi, 209 p.Cohesionless soils exist across the globe, under various geological settings and climatic regimes, in two distinct natural states. Disintegrated sediments, where soil particles are loosely held together through particle interlocking such as freshly deposited sediments, and intact deposits, in which soil particles are primarily held together through interparticle suction bonding. The geotechnical behavior of such soils is governed by field conditions of applied stress and atmospheric conditions. This research focused on developing a clear understanding of the saturated-unsaturated behavior of cohesionless soils by mimicking the two natural soil states for laboratory investigations (flow-through, volume change, and shear strength) and by using the test results for numerical modeling (two-dimensional and transient seepage-thermal and stability analysis). The main contributions of this research are summarized below.
A simple test method was developed, by utilizing a single sensor and a digital camera, to determine the unsaturated hydraulic conductivity over the entire suction range. The soil exhibited a marginal water holding capacity with air entry value of 8 kPa and a residual suction value of 21 kPa. Following a newly developed sigmoidal function, the soil exhibited a low hydraulic conductivity of 10-7 m/s (saturated value) that gradually decreased with increasing suction (desaturation). Likewise, the difference between the fitted unsaturated hydraulic conductivity values based on upper (10-5 m/s) and lower (10-7 m/s) limits of saturated hydraulic conductivity decreased with suction and converged at vapor conductivity (10-14 m/s).
The conventional oedometer test was improved, by adding a controlled water inflow and a digital data recording, to determine collapse and consolidation. Results showed that with the increase in pre-collapse stress from 25 to 600 kPa, unsaturated compression increased from 0.5 to 5.3% in disintegrated soil and remained close to 0.5% in intact soil. The wetting collapse decreased from 1.1 to 0.1% in disintegrated soil and increased from 6 to 9% in intact soils whereas the total collapse increased from 2 to 5.6% (disintegrated) and from 6 to 9% (intact). The transient volume change during wetting collapse followed a curvilinear trend for both soil states.
The conventional direct shear test was used to determine the shear strength parameters of disintegrated and intact soils under saturated and dried conditions. The disintegrated soil exhibited identical behavior under both saturation states with no clear peak at failure. Apparent cohesion was not observed and friction increased from 44.5° (saturated) to 48°(unsaturated). The intact soil behaved similar to the disintegrated soil in saturated state due to the absence of suction and had a clear peak and residual similar to dense soils. Apparent cohesion and friction angle respectively increased from 0 kPa and 42° (saturated) to 91 kPa and 36° (unsaturated).
A transient and two-dimensional seepage-thermal model was developed to determine the stability of typical embankments with a low slope (18 m) and high slope (26 m). These slopes were analyzed under mean, extreme wet, and extreme dry climatic conditions along with four ponding conditions (none, upstream, downstream, both) with and without vehicular loading.
The laboratory protocols and the numerical model are crucial for shallow and young geological deposits that are in direct contact with the atmosphere and where most civil infrastructure resides. The findings of this research are useful for the near design, construction, and rehabilitation of urban facilities exposed to climatic change impacts.Studentye
Perspectives on reform: a cross-border analysis of sex work policy in New Zealand
No full textA Practicum Report Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Social Work, University of Regina. vi, 54 p.This practicum report outlines my experience as a graduate social work student at the University of Regina, travelling to Auckland, Wellington, and Christchurch, New Zealand to complete an international practicum placement with Aotearoa/New Zealand Sex Worker’s Collective (NZPC). The goals of my practicum were to advance my graduate level social work knowledge and to engage with an area of social work that would provide me with a deeper understanding of macro social work practice while working alongside those working within sex work in a country where it is decriminalized. This report will include a literature review, exploring the various policies that inform sex work legislation globally, while highlighting the advantages that adopting a full decriminalized approach to sex work has. As highlighted by the New Zealand Model, a comparative analysis will be completed on the current legislative landscape within Canada. Additionally, this report will include personal reflections that occurred throughout my placement, including the connection of direct practice to personal values and ethics. Completing a practicum placement with NZPC has been an invaluable opportunity that has supported me in advancing my social work practice within a variety of areas. Through my work alongside NZPC, I developed an understanding of how the sociopolitical and legal frameworks for sex work in New Zealand and Canada differ, gaining a deeper understanding of policy reform.Studentye
Assessment of demographics and motivations of post-consumer textile waste management using a bibliometric approach
No full textThis version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s10163-024-01994-8Proper management of post-consumer textile waste (PCTW) is vital to the sustainable development of circular economy. This study systematically analyze PCTW studies from 1995 to 2021 focusing on demographics, motivations, and reasons of PCTW management. A PRISMA approach is adopted for the bibliometric analysis. It is found that very few PCTW studies focused on the behavioral, physiological, and cultural aspects. Recently, there is an increasing trend in PCTW publications, with a 73% increase in research output over the 15 years. USA stands out as the most productive country. Demographics such as income, age, and gender appeared to be the most significant role in shaping consumer behaviors, contributing to around 50% of the studies. There is a lack of studies involving participants below the age of 18, omitting one of the key stakeholders of PCTW management. We found gender bias in research participants, and many published PCTW studies focused exclusively on female consumers. Convenience and the condition of clothing items are important factors influencing consumer disposal decisions, while environmental concerns are pivotal motivations driving recycling behaviors. More studies on gender stereotyping and cultural appropriation are recommended to better understand PCTW generation, recycling, and disposal behaviors.The research reported in this paper was supported by a grant from the Natural Sciences and Engineering Research Council of Canada (DH-2023-00488) to the corresponding author. The lead author (Amal Ben Abdallah) was also supported by a Mitacs Globalink research award
Time-optimal motion planning of multiple collaborative robots for pick-and-place tasks
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 Industrial Systems Engineering, University of Regina. xi, 157 p.The ongoing revolution in robotic automation presents unparalleled opportunities and complex challenges for manufacturing industries. This thesis investigates optimization strategies for a fundamental robotic action: pick-and-place operations. Utilizing MATLAB's Robotics Toolbox, we devise detailed simulations, ranging from dual-robot static workflows (Scenario 1) to conveyor-integrated dynamism (Scenario 2). This research employs diverse optimization techniques that leverage both kinematic modeling and an analysis of robot dynamics for trajectory planning.
The outcome? Significantly shortened task execution times through iterative trajectory refinement and tailored adjustments to the simulated work environment. Results not only underscore the tangible impact of simulation-driven optimization, but also point towards conveyor speed control as a key avenue for driving further efficiency gains. These findings offer a framework for continued improvement, and aim at facilitating real-world implementation of these optimized, robotic motion-planning strategies across future manufacturing contexts.
Keywords:
Robotic Manipulation, Optimization, Simulation, MATLAB, Trajectory Planning, Manufacturing Automation, DynamicsStudentye
Implicit and explicit approaches for efficient healthcare scheduling
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 Computer Science, University of Regina. xv, 125 p.Combinatorial optimization problems play a major role in tackling applications such
as healthcare, transportation, education, etc. Solving these applications usually involves
satisfying a set of hard constraints while optimizing one or more objectives.
In this context, exact or approximate methods can be used. While exact methods
guarantee the optimality of the solution returned, they often come with an exponential
running time as opposed to approximate methods that trade the solution’s
quality for a better running time cost. In this context, we tackle the Nurse Scheduling
Problem (NSP). The NSP consists in assigning nurses to daily shifts in a given planning
horizon such that workload constraints are satisfied while hospital’s costs and
nurses’ preferences are optimized. To solve the NSP, we propose implicit and explicit
approaches. In the implicit solving approach, we rely on Machine Learning (ML)
methods based on Association Rules Mining (ARM) and classification algorithms using
historical data (past scheduling solutions) to learn and generate new solutions
through the implicitly learned constraints and objectives that may be embedded in
the learned patterns (e.g., Association Rules, trained ML models, etc). To quantify
the quality of using our implicit approach in capturing the embedded constraints and
objectives in historical data, we rely on the Frobenius Norm (FN). The latter is a
quality measure used to compute the average error between the generated solutions
and historical data. To compensate for the uncertainty related to the implicit approach
given that the constraints and objectives may not be concretely visible in the
produced solutions, we propose an alternative explicit approach where we first model
the NSP using the Constraint Satisfaction Problem (CSP) framework. Then we develop
Stochastic Local Search (SLS) methods and a new Branch and Bound (B&B)
algorithm enhanced with constraint propagation techniques and variables/values ordering
heuristics. Considering that our proposed implicit approach may not guarantee
the feasibility and/or optimality of the generated solution since the constraints and
objectives are represented through the learned patterns from the data, we propose a
data-driven approach to passively learn the NSP as a constraint network from historical
data. The learned constraint network, formulated as a CSP, will then be solved
using the methods we listed earlier.Studentye
Exploring the impact of limited information in active Bayesian learning
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 Computer Science, University of Regina. ix, 90 p.We tackle the problem of Noisy Bayesian Active Learning in a limited information
setting. Originally explored by Cecchi and Hegde1 , this problem involves a Bayesian
learner that sequentially selects oracles to determine the true class label of an incoming
object, with the goal of minimizing the number of samples while maintaining a low
error probability. The oracle's response is not a direct class label but a cluster label
that is corrupted by noise. Additionally, the learner is only given an estimate of the
true quality of those responses.
We extend Cecchi and Hegde's framework to a more general scenario, where each
oracle partitions the set of all possible class labels in its own unique way and provides
a non-binary cluster label when selected. The learner has at its disposal a quality
estimate for each predicted cluster label. We investigate the learner's performance
under this limited information setting.
During our study, we identi ed some oversights in the proofs of the lower and
upper bounds on the sample size proposed by Cecchi and Hegde. Our contribution
includes highlighting how these oversights necessitate a reassessment of the validity
of both bounds.Studentye
Absorption capacity of carbon dioxide in aqueous solution of 1,2-bis(3-aminopropylamino) ethane and Dytek EP diamine: Experimental measurements and simulation with the E-NRTL model
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. xiv, 103 p.The increasing threat of climate change has elevated the importance of carbon dioxide (CO2) capture technologies. This thesis explores the solubility of CO2 on aqueous solution of two novel amines 1,2-Bis(3-AminoPropylamino) Ethane and Dytek EP diamine at two different temperatures of 313.15 K and 333.15 K, and two different concentrations of 10 wt% and 30 wt%. These amines were selected for their potential to enhance CO2 absorption efficiency and reduce energy consumption in carbon capture and storage (CCS) processes to provide valuable data for developing more efficient CO2 capture systems. Utilizing the Electrolyte Non-Random Two-Liquid (eNRTL) model for the liquid phase and the RK equation of state for the gas phase, the research includes extensive thermodynamic modelling to simulate the experimental data and predict the behaviour of these amines in CO2 capture processes. The binary e-NRTL and molecule–ion pair parameters were obtained by regression. The overall percentage of the average absolute deviation (%AAD) between the experimental and estimated values for the temperature, pressure, and mole fractions are 0.006%, 0.052% and 0.015%, respectively, for 1,2-Bis(3-AminoPropylamino) Ethane, and similarly, 0.197%, 0.093%, 0.105% for Dytek EP diamine. 1,2-Bis(3-AminoPropylamino) Ethane showed superior solubility performance concerning other amines studied in the literature due to its high molecular weight and four amine groups in its structure, which increased its reactivity and decreased its steric hindrance. Dytek EP diamine had a moderate performance due to its lower molecular weight and the presence of only two amino groups and a methyl group in the structure, creating a steric hindrance and decreasing its capacity.Studentye
Policy priorities for aging adults with autism: Perspectives of personal support persons
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 Public Policy, University of Regina. xv, 139 p.Background: The field of aging with autism spectrum disorder is a rapidly growing area of research. Experts are increasingly focused on understanding the unique challenges faced by adults on the spectrum as they navigate aging. The challenges include aspects like maintaining independence, managing sensory sensitivities, and navigating potential changes in cognitive function. While these challenges are real, there is also a tremendous opportunity to discover and implement effective support systems. By learning more about the specific needs of adults with autism, we can develop targeted interventions and resources that empower them to thrive throughout their lives. This could encompass everything from social connection programs to sensory-sensitive housing options, and tailored healthcare plans. However, current literature highlights a significant knowledge gap in healthy aging among adults with autism.
Objective: This study aims to help fill this gap by exploring the perspectives of personal support persons (family, friends, caregivers) regarding what policy priorities are important to support aging well for adults with autism.
Methods: Using a qualitative semi-structured interview approach, the study explored the experiences, concerns, and priorities of personal support persons, aiming to identify policy gaps and opportunities for improving healthy aging within this under-researched group in the province of Saskatchewan.
Results: The personal support persons interviewed in this study discussed challenges that the adults with autism they support face upon entering adulthood, especially in areas like employment, housing, transportation, and healthcare in the province of Saskatchewan. The study's results highlight key themes identified through participant interviews, analyzed within Sen's capability approach framework. This framework focused on capabilities (what a person can
do), opportunities (resources available to the person), and freedom (choice and control) as crucial elements in understanding policy priorities to support the healthy aging of adults with autism. By examining these themes, the study underscored the need to move beyond mere service provision to empower individuals and advocate for inclusive policies. This study produced insights into how to better support adults with autism. This study found a need for tailored interventions, continuous and timely accessible support services, and policy changes that promote social inclusion.
Conclusion: Using the capability approach, this research suggests specific recommendations such as improved support service navigation, social inclusion programs, retirement planning, and tailored insurance plans. Overall, this approach emphasizes a comprehensive strategy to create a more supportive environment for adults with autism to age well.
Key Words – healthy aging, adults with autism, personal support persons, Sen's capability approachStudentye
Search Timelines: Contextualized search history in support of exploratory search
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 Computer Science, University of Regina. xiv, 151 p.The timespan over which exploratory searching can occur, as well as the scope
and volume of the search activities undertaken, can make it difficult for searchers to
remember key details about their complex search tasks. These difficulties are present
both during a single search session and when resuming a search task that spans multiple
sessions. Existing public digital library search interfaces do not provide adequate
support to allow patrons to pursue a complex search task for a prolonged period
across multiple sessions. In this thesis, I present a novel search interface designed to
support cross-session exploratory search in a public digital library context through
the introduction of Search Timelines. The interface provides context for past and
current search activities via a dynamically updating timeline of the search (queries
and saved documents). This timeline is presented alongside the search results in a
typical search engine results page design. A more detailed timeline is provided in a
workspace, where searchers can review the history of their search activities and their
saved resources. In order to assess the value of Search Timelines, a controlled laboratory
study was conducted to compare it with a baseline interface modelled after the
Regina Public Library search interface. The results of this study show that searchers
were more engaged while working with Search Timelines both during the initial search
session and when resuming the search after a gap of 7-8 days. The results also show
the value of the novel interface in terms of usability measures, perceived knowledge
gain, and search performance for both initial and resumed sessions. Overall, the
results illustrate that Search Timelines can effectively support public digital library
searchers while performing exploratory search that span multiple sessions.Studentye