21793 research outputs found
Sort by
Hydrodynamics of placing off-bottom plugs in oil and gas wells
Get PDFIn this thesis, we aim to unravel hydrodynamic challenges of common plug placement processes during the abandonment of oil and gas wells. Placing plugs in wells often starts with injecting cement slurry in wellbores filled with lower-density liquids (e.g. water). We develop a 2D model to investigate the flow dynamics during this process.
We first consider the ideal case where the injector and the wellbore are concentric. We illustrate that the injected fluid develops a finger below the injector. The finger breaks after an instability develops at the interface, leading to enhanced mixing below the injector. A mixed layer thus forms and prevents the downward displacement of the injected fluid and the placement failure.
The injection configuration is often far from ideal in field operations. We investigate the effect of the injector size and position in the wellbore. We illustrate, through different mechanisms, that the downward flow of the injected fluid is disrupted for a wide range of injector sizes and positions. However, the water content of the accumulated fluid varies notably with both geometric factors.
Exploring the range of density differences relevant to the placement operations, we characterize the changes in the flow dynamics and identify two displacement flow regimes where the front velocity either remains constant or accelerates after a quasi-steady velocity. Regardless, the displacement flow is unstable and is followed by the accumulation of the injected fluid.
To investigate the effect of the domain geometry on the predicted flow features, we conduct a brief comparison of the flow dynamics in 2D and 3D domains with and without the assumption of flow symmetry. We show that the 2D model is more effective in predicting the flow features compared to models which presume flow symmetry, when the flow is not known to be axisymmetric priori.
Placing the plugs often ends with pulling the injector out of the wellbore. Using a similar 2D model, we illustrate that the density unstable interface of the plug is affected by the pull-out only when the interface is very close to the injector. Pulling at lower velocities seem to facilitate the mixing at the interface
Experience-dependent plasticity in cortical and cerebellar regions of early- and late-trained musicians
Get PDFA body of current evidence suggests that there is a sensitive period for musical training: people who begin training before the age of seven show better performance on tests of musical skill, and also show differences in brain structure – especially in motor cortical and cerebellar regions – compared with those who start later. In two studies, we investigated distributed patterns of structural differences between early-trained (ET) and late-trained (LT) musicians. First, we examined structural covariation between cerebellar volume and cortical thickness (CT) in sensorimotor regions in ET and LT musicians and non-musicians (NMs). We found that early musical training had a specific effect on structural covariance between the cerebellum and cortex: NMs showed negative correlations between left lobule VI and right pre-supplementary motor area (preSMA) and premotor cortex (PMC), but this relationship was reduced in ET musicians. ETs instead showed a significant negative correlation between vermal IV and right pre-SMA and dPMC. In the second study, we used support vector machine models – a subtype of supervised machine learning – to investigate cortico-cerebellar structural covariation and to better understand the age boundaries of the sensitive period for early musicianship. Our model identified a combination of 17 regions, including 9 cerebellar and 8 sensorimotor regions, that accurately identified ET and LT musicians with high sensitivity and specificity. Critically, this model – which defined ET musicians as those who began their training before the age of 7 – outperformed all other models in which age of start was earlier or later (between ages 5-10). Our model’s ability to accurately classify ET and LT musicians provides additional evidence that musical training before age 7 affects cortico-cerebellar structure in adulthood, and is consistent with the hypothesis that connected brain regions interact during development to reciprocally influence brain and behavioural maturation. Together, these results suggest that early musical training has differential impacts on the maturation of cortico-cerebellar networks important for optimizing sensorimotor performance. This work enriches our understanding of how experience-dependent plasticity is affected by early musical training, providing a more nuanced understanding of the interrelated nature of brain development
An Investigation of the Volatile Organic Compound Degradation Capacity of the Oligotrophic Surface Water Microbial Community of the Arctic Ocean
Get PDFThe summer surface waters of the Arctic Ocean (AO) are among the most oligotrophic marine ecosystems on Earth. The AO is also influenced by variable sea-ice and sunlight. Little is known about how marine bacteria have adapted to survive this extreme Arctic habitat. Volatile organic compounds (VOCs) are increasingly recognized as important resources for bacterial metabolism in oligotrophic oceans. Studies show that the AO is a net sink for VOCs leading to the hypothesis that Arctic Ocean bacteria consume VOCs. To test this hypothesis, we investigated a genome catalogue of AO prokaryotes for the presence of VOC-degradation pathways. A carboxylation pathway for acetone degradation dominated the surface waters. The key enzyme (acetone carboxylase) allows bacteria to access CO2 through acetone carboxylation, suggesting a type of heterotrophic CO2 fixation may operate in the AO. The acetone-consuming bacteria were mostly represented by a single population of Porticoccus bacteria (SP-01). The genome encoded few organic carbon transporters, but proteorhodopsin genes were identified indicating heterotrophic metabolism could be supplemented with energy from sunlight. Metatranscriptome analysis revealed that acetone carboxylase and proteorhodopsin were among the most highly expressed genes, indicating significant investment in the exploitation of acetone and sunlight in carbon and energy metabolism. Through 2004-2017 SP-01 had a 1-8% annual average abundance, peaking in 2017, a year distinguished by a longer ice-free period. The future relevance of bacteria, such as SP-01, adapted to AO oligotrophic surface water may increase with a warming Arctic, when ice-free conditions prevail, and ocean stratification and subsequent oligotrophication intensifies
Traditional Japanese Material Practices as a Model for Sustainability in Clothing Design
Get PDFThis research-creation explores how traditional Japanese materials and methods can inform the production of a garment that contributes to understanding alternative clothing design and consumption practices. The thesis is a response to the unsustainability of a fast-paced industry driven by low-cost production, toxic dyes, material waste, disposability, and overconsumption at the expense of the environment. Moving towards a sustainable future requires rethinking the entire garment lifecycle from sourcing to production and consumption.
Japan’s rich traditional textile history of using diverse bast fibers, natural dyes, and small run and no waste productions may offer designers a way forward. In this thesis, the principles of mottainai and shinto are intertwined with slow fashion and design-with-care. The research methodology was conducted in three phases: (i) an experiential field study in Japan; (ii) a contextual analysis of formal literature and experiential learning; and (iii) material and performative experimentation through sourcing of biodegradable materials and food waste for colouring; carrying out dye experiments; zero-waste patterning, to uncover viable solutions. The result of my investigations is a hanten, a traditional Japanese jacket, which I adapted for use in the Quebec winter climate.
Further emphasizing the Quebec context, I worked in collaboration with local professionals for the jacket’s quilted milkweed insulation and patternmaking and sewing techniques. My aim has been to design a one-off garment prototype to represent some of my ideas and processes. In future research-creation, I hope to address the potential of this thesis paper and hanten jacket as a model for multi-garment production in Quebec
Beyond Universal Gamification: Exploring Persian Gamification Strategies
Get PDFThe variety of culture across the world, leads to the existence of distinctive values and dissimilar behavior among people. Taking this into account is crucial in the interaction design process. This research aims to integrate the unique values of a cultural background into the design of persuasive technologies, specifically applications and websites. Persuasive technology is where persuasion and computers overlap. It is where through the means of technology, we can help people improve their lives.
This research targets Persian culture, and investigates its notable traits through practical and theoretical research methods. It connects the findings to the theories of motivation and gamification, and brings up new motivational strategies for an exercise running/walking app. Exercise was chosen as the theme of the work since it exemplifies a domain that many people require extra motivation to get to and it has been one of the highly in-demand fields in the area of gamification.
This research evaluates the amount of effectiveness of the Persian motivational strategies on various audiences with direct and indirect connections to Iran. It also examines the reflections of people who have no connection to Iran at all. Throughout this process, the goal is to validate whether or not gamification can exist in different cultural registers, and if so, defines the parameters of Persian gamification
Planning Urban Mobility within the UN Sustainable Development Goal Framework
Get PDFSustainable development is about raising human well-being and protecting the environment. In the context of urban sustainability, cities have prioritized cars leading to negative impacts on society and the environment. Some scholars are concerned that planners do not incorporate equity in the state of the practice. Individuals facing social exclusion are more vulnerable to low air quality, traffic collisions, and noise. Moreover, stronger mitigation measures are needed since the transport sector is the second largest contributor to emissions.
A conceptual investment framework was designed to interconnect the Sustainable Development Goals (SDGs) for planning and designing sustainable urban mobility under five strategic areas: social justice, health, climate change, economic development, and governance. Policies, modeling tools, and methodologies were reviewed to construct this framework under a systems approach.
To analyze the 2050 net-zero policy of changing the vehicle fleet from Internal Combustion Engines (ICE) to Electric Vehicles (EVs), a bottom-up regional average speed emission model relying on a four-step travel demand was developed. Four scenarios were explored: business as usual (BAU), low, moderate, and aggressive to evaluate the potential reduction of carbon dioxide (CO2) emissions, Nitrogen Oxides (NOx), and Particulate Matter PM2.5. The emission model included vehicle speed and weight, fuel type, and vehicle emission standards. In the case study of Costa Rica, it was found that attaining zero CO2 emissions by 2050 requires shifting to EVs at least 25% and 50% by 2030 and 2040, respectively. For ICE vehicles, changing the minimum vehicle emission standards from EURO 1 to EURO IV and EURO VI positively impacted the reduction of NOx and PM2.5 despite the growth of traffic volumes.
This research explored the barriers women face to having equal opportunities and differentiating urban mobility needs and patterns. A vertical equity transport planning approach that is pro-poor, gender-sensitive, and considers intermediary social health determinants is developed. This research is the first approach to incorporate the most at-risk demographics (material deprivation, disabilities, and single mothers' car ownership) and their exposure to NOx and PM2.5 in identifying high-priority areas
Shrink: Story of a Fat Girl: An Interdisciplinary Approach to the Fat Body in Medicine and Society
No full textABSTRACT
Shrink: Story of a Fat Girl: An Interdisciplinary Approach to the Fat Body in Medicine and Society
Rachel M. Thomas, Ph.D
Concordia University 2023
This dissertation contextualizes data collected and synthesized in the research creation project Shrink: Story of a Fat Girl: a two-hundred-page graphic novel that examines the fat body in contemporary Western culture. It is a collection and critical examination of the current medical and sociological views on fatness from a pluridisciplinary perspective using specific examples from Shrink as a base for argument.
The aim of Shrink is to question the discourse around fatness, from extensive research and
personal experience. Graphic novels are a format that are accessible to a larger public. The graphic novel now has a place in the growing field of graphic medicine which seeks to connect with individuals in both academic and non-institutional formats.
Shrink is the experiential journey of the book’s unlikely hero as she chooses to lose weight in a world that has dictated the medical and social dangers of being too fat. The novel takes the reader through the social complications of fatness, the medical gaze upon the female body, monstrous bodies, and diet culture. It examines the notion that weight loss is the only solution for a fat person. Shrink also reviews the damaging myths of the ‘perfect’ body, obsessions about healthism, pushback from activists and why, ultimately, it is so important for a person to demand autonomy over their own body. Shrink is about choices; to lose weight or not in a society of contradictions
A Data-Driven Optimization Model for Medical Resource Allocation during the Pandemic
Get PDFThe outbreak of Covid-19 in recent years has once again brought the critical issue of medical resource allocation during a pandemic to the forefront of research and public attention. The dynamic and rapid nature of the pandemic has posed significant challenges in accurately predicting the demands for medical resources and developing effective strategies for their distribution. In this study, we aim to address these challenges by studying the medical resource allocation problem during a pandemic and proposing a data-driven optimization methodology that combines mathematical programming and machine learning techniques.
To tackle the problem of demand prediction, we utilize a Long Short-Term Memory(LSTM) model to predict medical resource demand using historical pandemic time series data. Building upon the demand predictions, we develop a linear programming model to optimize the allocation of medical resources. The objective is to maximize the total accessibility of hospitals within each region while also ensuring a balanced distribution of accessibility across all regions. We also conducted a case study on the application of this framework to the Quebec, Canada, pandemic hospitalization case scenarios. The dataset we utilized consisted of hospitalization case numbers from 16 regions in Quebec, along with the geographical locations of 15 regions and their corresponding healthcare facilities. The prediction performance is evaluated by mean absolute error(MAE) and root mean square error(RMSE), which yielded average values of 3.079 and 5.491, respectively. And after optimizing, the total accessibility of all regions is 4.503. The results indicate the effectiveness of our proposed method in accurately predicting future hospitalization numbers and determining the necessary increase in bed capacity for each region, showcasing its potential to assist in resource planning and allocation during a pandemic
Interpretation, Materiality, and Subjectivity: New Materialism's Challenge to Hermeneutics
Get PDFThis thesis attempts to bridge the recent gap between materiality and subjectivity in social theory. The material world is increasingly becoming a central topic in social theory. Emerging from this movement, new materialism turns our attention to a physical, tangible world that exists outside of our interpretations and representations of it. This new focus on materiality is however usually seen as being incompatible with theories that came out of the linguistic turn in philosophy during the second half of the 20th century because these focus on subjective understandings of socially constructed realities. We are now faced with two distinct agendas in social theory with one focusing on materiality and the other on subjectivity. Environmental justice turns our attention towards the materiality of the Earth and social justice claims that we rather need to focus on specific subjectivities for emancipation. To break this stalemate in social theory, and to bridge the distance between environmental justice and social justice this research sets up an encounter between the vital materialism of Jane Bennett and the hermeneutic phenomenology of Paul Ricoeur. A connection is found in both theories’ critique of modernity
Life cycle assessment of bioenergy production using wood pellets: The case of remote communities in Canada
Get PDFAbstract
Life cycle assessment of bioenergy production using wood pellets: The case of remote communities in Canada
Saghar Sadaghiani
A reliable and environmentally friendly energy source is crucial to remote Canadian communities. Currently, fossil fuels are the primary source of electricity and heat in these communities. Diesel generators mostly powered these communities, contributing to climate change due to fuel transportation and emissions. Therefore, there is an urgent need to reduce fossil fuel reliance in these communities. We examined wood pellets’ use in a remote Canadian community using Life Cycle Analysis (LCA). In addition, the combustion of wood pellets will be compared with diesel combustion. To perform the LCA, we utilized SimaPro (version 8.4.0.0), a widely used software for conducting LCA. SimaPro provides a comprehensive platform for modeling and analyzing the environmental performance of products or processes. The Ecoinvent 3 library also provided life cycle inventory (LCI) data for a variety of materials, processes, and energy systems. Pellets LCA covered harvesting, transportation, sawmill operation, pellet production, and combustion stages. Our first step was to collect data on these five stages. Furthermore, these stages were compared in eight impact categories (Global warming, carcinogenic, non-carcinogenic, ozone depletion, respiratory effects, smog, acidification, ecotoxicity, eutrophication, and fossil fuel depletion). According to the results, pelletization and combustion are the most harmful stages to the environment, especially non carcinogenics effects for the pelletization and respiratory effects of pellet combustion. Lastly, we compared wood pellet combustion with diesel combustion to assess bioenergy's efficiency. We found that the combustion of wood pellets performs better in many impact categories than in burning diesel, especially in non-carcinogenic ones