SACM - Canada
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Item Restricted Modulation of Aryl Hydrocarbon Receptor-Regulated Genes by Methylmercury(University of Alberta, 2024) Alqahtani, Mohammed Ali; Ayman, ElKadiEnvironmental pollution poses a significant threat to public health, with various contaminants contributing to a wide range of adverse health effects. Among these contaminants, ؤ (MeHg) and the aryl hydrocarbon receptor (AHR) ligand 2,3,7,8-tetrachlorodibenzodioxin (TCDD) are particularly concerning due to their persistence in the environment and potent biological activities. Both compounds have been extensively studied for their individual effects, but the potential health risks associated with their combined exposure are less understood. The primary objective of this work was to investigate the individual and combined effects of MeHg and TCDD on AHR-regulated enzymes. This investigation was conducted using the murine hepatoma Hepa-1c1c7 cell line and extended to mouse hepatic and extrahepatic tissues. The effects of MeHg on Ahr-regulated gene expression were examined in the absence and presence of TCDD, along with evaluations of protein expression and enzymatic catalytic activity. In hepatic tissue, both MeHg and Hg2+ inhibited the TCDD-mediated induction of Cyp1a1/1a2 mRNA levels. However, only Hg2+ inhibited the TCDD-mediated induction of CYP1A1/1A2 protein and catalytic activity at posttranscriptional levels, indicating differential modulation by Hg2+ and MeHg. Additionally, the inhibitory role of HO-1 (heme oxygenase-1) on CYP1A activity induced by TCDD was investigated in vitro using the HO-1 competitive inhibitor tin-mesoporphyrin, which partially restored the MeHg-mediated decrease in CYP1A1 activity. In extrahepatic tissues, MeHg exhibited mainly inhibitory effects, particularly decreasing the basal level of Cyp1a1 and Cyp1a2 mRNA and protein, which was more evident at the 24-hour time point in kidneys, followed by hearts. Similarly, when mice were co-exposed, MeHg reduced the TCDD-induced Cyp1a1 and Cyp1a2 expression. However, MeHg potentiated kidney Cyp1b1 mRNA expression, opposing the observed change in its protein level. Exposure to MeHg induces several antioxidant enzymes, including NAD(P)H:quinone oxidoreductase (NQO1), whose expression is regulated by both AHR and nuclear factor erythroid 2-related factor-2 (NRF2). This co-regulation prompted an investigation into which transcription factor primarily orchestrates NQO1 expression upon MeHg exposure. Our findings demonstrate that NQO1 induction by MeHg is, at least in part, mediated by NRF2. In conclusion, the findings of this work reveal an intricate interplay between MeHg and TCDD on AHR-regulated CYP1 enzymes, with notable inhibitory effects that might be significant for procarcinogen metabolism. Varied responses across tissues highlight the potential implications for environmental health.7 0Item Restricted Sociocultural Determinants of Children’s Oral Health Among Immigrants: Developing and Testing a Conceptual Model(university of alberta, 2024) Dahlan, Rana; Amin, MaryamBackground: The Canadian Collaboration for Immigration and Refugee Health highlights oral health diseases among the top 11 health challenges for immigrants and refugees. Foreign-born individuals face higher vulnerability due to migration-related disruptions and limited dental access. Cultural shifts, known as "acculturation," impact immigrants' health, varying in degree. Understanding this requires considering post-migration socio-cultural context. Social connections change post-migration, affecting oral health, well-being, and quality of life. Recognizing these shifts is crucial for stakeholders: dentists, community workers, and researchers. Social support is vital for new immigrants, aiding adaptation, and healthcare access. Both parental acculturation and support shape children's oral health. Their combined impact on oral health remains underexplored in existing literature. Objective: The overarching objective of this research was to construct and assess a conceptual model aimed at predicting oral health behaviors and caries experience of immigrants’ children. The goal was to develop a model that explains the sociocultural factors influencing children’s oral health among immigrants, using Structural Equation Modeling (SEM). Methods: This study unfolded in three phases, beginning with ethics approval from the University of Alberta Research Ethics Board (Protocol # Pro00072345). The first phase encompassed two systematic reviews: one focused on acculturation's impact on oral health among immigrants and ethnic minorities, while the other explored social support's influence on oral health in these groups. The second phase, a cross-sectional study, investigated how parental acculturation and perceived social support affected their children's oral health behaviors and caries experience. Participants included first-generation immigrant parents residing in Canada for two or more years, with children aged 2–12 years. Data collection took place in convenient community settings through multilingual community workers using non-probability snowball sampling. Parents provided demographic, perceived social support, acculturation, and children's oral health behavior data. Trained dentists conducted dental exams and used the DMFT/dmft index to assess caries experience. Oral health behaviors were measured with an eight-item questionnaire. The main independent variables were parents' perceived social support (PSS),measured using the validated Personal Resource Questionnaire (PRQ2000) and parents' acculturation and strategies were evaluated with the Asian American Multidimensional Acculturation Scale (AAMAS). The data collected in the second phase informed the creation of a conceptual model in the third phase, aimed at predicting immigrant children’s oral health behaviors and caries experience through Structural Equation Modeling (SEM), examining parental acculturation and perceived social support's influences. Results: A total of 336 parent/child pairs participated in the study. The average parental acculturation level was 10.46, and the average perceived social support (PSS) score was 63.27. Factors like length of residency, parents' education, and household income significantly predicted acculturation level. Parents with higher Canadian cultural knowledge reported more frequent children's toothbrushing. Parents of children consuming >1 sugary item/day had higher acculturation levels, English language proficiency, and Canadian food adoption. Parents of recent dental visitors reported higher assimilation and lower separation scores, while those visiting due to problems had higher marginalization scores. Parental acculturation wasn't significantly linked to children's dental decay (DMFT/dmft). Household income predicted parental PSS (B = -5.69). Children of parents with higher PSS brushed teeth ≥2/day. Parental education predicted social integration and nurturance; income predicted social integration, worth, and assistance. Parents with more intimacy and social integration were more aware of children's oral health. Parental social integration scores were higher when children consumed ≥1 sugary snack/day. All domain scores were higher when children brushed teeth ≥2/day. Structural Equation Modeling (SEM) indicated 77% of DMFT/dmft variance was explained by parental PSS, acculturation, predisposing/enabling factors, and children's oral health (OH) behaviors. Parental PSS had a direct effect on reduced dental caries and sugar consumption. Parental acculturation mediated by positive OH behaviors increased caries risk. Conclusions: The SEM analysis found significant variance in immigrants’ children's caries experience. Findings highlight parental acculturation and PSS levels predicting oral health behaviors and caries. Recognizing sociocultural factors is vital for stakeholders—dentists, community workers, and researchers. Immigrants' vulnerability to oral health issues underscores the need for deeper exploration and expanding the model.1 0Item Restricted Exposure to Allergens and Proinflammatory Mediators Modulate Airway Epithelial Cell Innate Responses, Metabolism, and Physiology(University of Alberta, 2024) Alzahrani, Khadija Rashed; Vliagoftis, HarissiosLungs and airways health and protection depend on the integrity of airway epithelium. Insulin is a growth hormone that through activation of several signaling pathways play a central role to maintain cellular growth and activate metabolism. Airway epithelium is in constant exposure to inhaled agents like pathogens, allergens, pollutants, and particular matters. Airborne allergens like cockroach or house dust mite (HDM) contain proteases that can interact with airway epithelium and initiate immune responses through activation of airway epithelial cells and innate immune cells. Airway epithelium cytokines and innate immune cells promote activation of adaptive immune cells like Th2 lymphocytes that produce proinflammatory mediators like interleukin-4 (IL-4), IL-13, and IL-5. T helper 2 (Th2) cytokines amplify the immune responses and stimulate airway epithelial cells to release CCL chemotactic factors/eotaxins that attract eosinophils to the site of inflammation. Airway epithelium exposure to inhaled irritants and excessive inflammatory responses is known to disrupt epithelium integrity and exacerbate inflammatory responses. Th2 inflammation in asthma is associated with epithelial injury, epithelial remodeling, and metabolic alterations. Increased expression of inflammatory mediators tumor necrosis factor (TNF) and IL-6 in metabolically active tissues have been associated with cellular damage and insulin resistance. Inducible AECs local inflammation was shown to trigger systemic inflammation, insulin resistance, and impaired glucose metabolism, and the severity of inflammation correlated with impaired glucose metabolism. Several studies showed that insulin resistance increased the risk of aeroallergen sensitization and developing asthma-like symptoms. In this project we hypothesized that exposure of airway epithelial cells (AECs) to allergens and proinflammatory mediators may modulate Th2 immune cell responses, induce insulin resistance and metabolic shifts. First, we examined the effect of cockroach and house dust mite on IL-13 and IL-4-induced inflammatory responses. AECs were cultured and stimulated with cockroach or house dust mite, IL-13, IL-4, or a combination of an allergen and IL-13 or IL-4. IL-13 and IL-4 induced effects were measured. Then, we tested the effect of cockroach, house dust mite, TNF or IL-6-induced inflammatory responses on physiological epithelial changes and insulin-induced effects. Epithelial proliferation, resistance, energetic phenotype changes, and insulin induced activation of PI3K/Akt were examined. We showed that serine proteases of cockroach extract prevented IL-13-induced expression of eosinophil chemokine CCL26 from AECs. Depletion of CCL26 was previously shown to delay resolution of airway allergic inflammation which may result in prolonged eosinophilia. Prolonged inflammation was linked to altered metabolism and insulin action in several studies. We showed for the first time that house duct mite and TNF modulated insulin effects in AECs. TNF and HDM changed insulin-induced ATP production in AECs. Additionally, TNF reduced insulin-induced Akt phosphorylation, reduced epithelial barrier function and recovery after injury. Our data suggest that cockroach serine proteases and TNF may interfere with the Th2-mediated proinflammatory effects, regulate AECs energetic phenotype, and induce insulin resistance. These inflammatory and metabolic changes exacerbate the pathogenesis of asthma which may alter immune cell responses.5 0Item Restricted A Comparative Case Study: Exploring Health System Governance in Canada and Saudi Arabia(Western University, 2024) Almalki, Fawziah; Oudshoorn, Abe; Tryphonopoulos, Panagiota; Smith, Maxwell; Muntaner, CarlesHealth systems and health system outcomes are incredibly complex. To understand how they function, researchers explore individual components of the system, in the study herein the component is ‘governance’. Research to date has demonstrated a positive relationship between governance and population health outcomes. Governance, therefore, may be a concept that assists in understanding differential health outcomes of seemingly comparable countries. This study aims to explore macro-level governance, particularly the two sub-concepts of ‘government effectiveness’ and ‘perceived corruption’, in two countries: Saudi Arabia and Canada. Government effectiveness reflects the quality of public health policy development and implementation, and how much the government adheres to these policies. These comparator countries are selected as they share similarities on three levels, economy, population size, and free basic healthcare; yet differ significantly in governance models. A case study methodology as described by Stake (1995), guided this study. This study is particularly a comparative case study design with a focus on qualitative data. The data will be used to understand in-depth nuances of governance in health systems. Two overarching questions guided this study, one for each of the sub-concepts: 1) How the government effectiveness process, in terms of health policy development and implementation, unfolds within the health system in Saudi Arabia and Canada. 2) How corruption, as an aspect of governance, is present within health systems. This work is framed within a critical theoretical perspective. Concerns about good governance and corruption that guide this work is to the purpose of seeking the best health outcomes for all people. Governance as a whole, and sub-concepts of government effectiveness and corruption, are all amenable to change and improvement. To engage with system complexity, multiple data sources were utilized within this case study. Primary data consisted of interviewing 32 participants (15 in Canada and 17 in Saudi Arabia) who work in the health system in service provision, research, policy, management, or education. Secondary data included government documents about health system structure and strategies at the macro level. Data collection was conducted through two phases. Phase one of data collection involved in-depth interviews with experts across the health systems. The interviews were conducted in both English and Arabic. Documents for analysis were collected and accessed through official websites of governments or Ministries of health, and healthcare organizations, and scientific databases. These documents were analyzed via Critical Discourse Analysis (CDA) as outlined by Van Dijk (1993) and Mullet (2018). The findings are divided into three foci as three chapters: 1) a methodological piece on conducting bilingual research; 2) the nature of government effectiveness; and 3) the nature of corruption in health systems. Conducting research in a language not spoken by all the research team members is relatively common, yet addressing the nuanced details of implementing bilingual work has limited guidance within extant literature. This includes consideration of promising practices for concept development, translation, data analysis, and presenting the findings. This chapter is an exploration of the strengths and limitations of doing bilingual research, and recommendations regarding these aforementioned issues from our own experiences. Ultimately, it is proposed that via bilingual research, the accumulation of knowledge pertaining to qualitative research concepts, translation, analysis, and dissemination of comprehensive frameworks can be enacted, ultimately enhancing the rigour of qualitative research and increasing confidence in applying knowledge created in the chosen language of participants. Findings on government effectiveness in health systems in both Canada and Saudi Arabia are presented in four themes. These four themes are: 1) Health is Political, 2) Health System Privatization, 3) An Outdated System vs. A System that is Catching Up, and 4) Social Determinants of Health (SDoH) and Cross-Sectoral Collaboration. Recommendations are provided on how to better identify elements of government effectiveness and integrate them with the SDoH in order to enhance system effectiveness and improve the health of populations. For the chapter on corruption, it is noted that Governance is a complex theoretical concept that includes the sub-concept of ‘corruption’. A very ‘loaded’ term, this study sought to understand how corruption is present in health systems, often in very subtle ways. Findings illustrate how corruption is still a relevant concept in advanced health systems and can include both subtle and even overt forms within Canadian and Saudi health systems. This is explained in three themes: 1) Corruption in Wealthy Nations: Subtle Opportunism; 2) Nepotism and Professional Courtesy; and 3) A Strict System vs A Relaxed System. This analysis uncovers nuanced forms of potential personal gain within Canadian and Saudi health systems that make the concept of corruption still a timely concern. Addressing these risks must be seen as a collective obligation, where healthcare providers identify and report cases of potential corruption, managers prevent and address opportunities for personal gain, and researchers study how to develop policies and processes that are most immune to corruption. Ultimately, this study continues to unpack the complex ways that health systems are actualized, looking particularly at the concept of governance, and selected sub-concepts of government effectiveness and corruption.28 0Item Restricted SMART AUTHENTICATION MECHANISMS: UTILIZING BIG DATA FOR DYNAMIC AND PERSONALIZED SECURITY SOLUTIONS(The University of Western Ontario, 2024-08-25) Abu Sulayman, Iman; Ouda, AbdelkaderThe exponential growth of digital data is revolutionizing information security and reshaping defense strategies against unknown threats. Organizations are amassing vast amounts of personal data, collectively termed ”Big Data,” from various sources like social media, online transactions, and GPS signals. This surge in data presents new research challenges in information security, prompting organizations to leverage big data analytics for valuable insights within secure environments. As a result, organizations are redesigning network security protocols to effectively manage the characteristics of big data. While traditional research focuses on authenticating users to protect big data environments, an alternative perspective emerges: utilizing big data to raise a new generation of authentication mechanisms to safeguard other environments. To this end, we developed novel security solutions that harness big data analytics to generate unique patterns of users’ dynamic behaviors, enabling the design of smart knowledge-based authentication mechanisms to fulfill the requirements of the new era of the digital world. These solutions include three main modules. ”Data Security-based Analytics (DSA),” the first module, develops an innovative data transformation model. The model adapts big data’s characteristics to relevant human dynamic measures. The second module, known as ”Big Data Driven Authentication (BDA),” includes the Security User Profiles (SUP) creation model, which is responsible for identifying patterns in DSA’s output and then uses said patterns to detect legitimate but anomalous activity from the user and assemble a security profile about the user. BDA also includes another model, known as Just-in-time Human Dynamics-Based Authentication Engine (JitHDA), which uses the user’s security profiles to dynamically create secure challenge questions in real-time that derive from the user’s recent behavior. The third module describes the development of a novel “Big Data-Driven Authentication as a Service (AUTHaaS)” model. AUTHaaS is an authentication mechanism that is powered by SUP and JitHDA technologies to offer authentication services on the cloud. Another model in AUTHaaS is ”iAuth,” which is an integration framework for authentication services. We developed this model to offer a unified interface that enables collaboration and interoperability among various AUTHaaS service providers. Additionally, we have developed an algorithm-based data generation (ADG) engine that is capable of processing synthetic user data. We designed ADG to accommodate dual-mode user behavioral data, encompassing both normal and abnormal instances. More importantly, the engine does not necessitate an initial dataset or data distribution and serves as the dataset source for the DSA model as it generates data from five different application domains.7 0Item Restricted Advancing Oncolytic Virotherapy: The Role of Chemical Sensitizers in Enhancing Viral Oncolysis in Resistant Cancers(University of Ottawa, 2024-07-28) Alwithenani, Akram; Diallo, Jean-SimonOncolytic virotherapy, leveraging viruses to target cancer selectively, has shown promise with the FDA-approved oncolytic herpes simplex virus-1 (HSV-1) for melanoma treatment. However, the efficacy of oncolytic viruses (OVs) varies across cancer types, highlighting the need for strategies to sensitize resistant tumors. This thesis investigates the potential of Dimethyl fumarate (DMF), its analog Tepilamide Fumarate (TPF), and novel synthetic small molecules identified from a high-throughput screen to enhance OV effectiveness in cancer therapy. DMF, approved for multiple sclerosis and psoriasis, and TPF, under trial for psoriasis, were evaluated for their ability to boost HSV-1 and vesicular stomatitis virus (VSVΔ51) activity against cancer cells. Our findings reveal that pre-treatment with DMF or TPF significantly increases HSV-1 and VSVΔ51 replication in various cancer cell lines, including melanoma, and improves viral oncolysis. Notably, both DMF and TPF enhance OV infection in mouse-derived tumor cores and human tumor samples, while TPF exhibits a remarkable capacity to heighten VSVΔ51 infection and cell killing, outperforming DMF in vitro. Both compounds achieve these effects by downregulating the interferon (IFN) pathway, rendering cancer cells more susceptible to viral infection. Additionally, we demonstrate the ability of DMF and TPF to boost gene therapy vectors' transduction efficiency, which points to the broader utility of these drugs in gene therapy. Further exploration through a high-throughput screen identified several small molecules that sensitize human renal carcinoma cells to HSV-1 and VSVΔ51, highlighting potential new avenues for overcoming tumor resistance to OVs. These compounds enhance viral replication and oncolysis, presenting a promising path for future oncolytic virotherapy research and development. The synergistic potential of combining approved therapies like DMF with OVs, the promising effects of TPF, and newly identified small molecule sensitizers underscore the feasibility of enhancing OV efficacy in resistant cancers. This study not only broadens our understanding of how small molecules can potentiate oncolytic virotherapy but also sets the stage for clinical evaluation and the development of more effective, personalized cancer treatment strategies. Collectively, these findings advocate for further investigation into DMF, TPF, and other sensitizing compounds to unlock their full therapeutic potential in oncolytic virotherapy.14 0Item Restricted Adaptation and validation of the U.S. hospital survey on patient safety culture 2.0™(SOPS®) : the Saudi version(University of British Columbia, 2024-07-12) Alharbi, Amal Ali; Dahinten, SusanBackground: The U.S. Hospital Survey on Patient Safety Culture 2.0 (HSOPSC, 2.0), released by the Agency of Healthcare Research and Quality in 2019, is the most widely used instrument for measuring patient safety culture in healthcare organizations. However, it has not been cross-culturally adapted nor validated within the context of the Saudi healthcare system. This two-phased study aimed to adapt the U.S. HSOPSC 2.0 to be suitable for use by registered nurses working in Saudi hospital settings, and to assess the construct validity of the revised Saudi tool. My approach to psychometric testing was informed by Messick’s view of unified validity (1980, 1995), and guidelines provided by the International Test Commission (2017). Methods: Instrument adaptation was performed in Phase 1 using a committee-based approach, two focus-group interviews, and expert panel reviews. Construct validity of the adapted tool was assessed in Phase 2 using confirmatory factor analyses, reliability testing, and hierarchical logistic regression, drawing on cross-sectional data collected from 534 registered nurses working in a large tertiary hospital setting in Saudi Arabia. Results: Phase 1 resulted in a 33-item instrument that demonstrated excellent content validity. In Phase 2, confirmatory factor analysis yielded the 26-item Saudi-HSOPSC 2.0 with a 10-factor structure consistent with the U.S. HSOPSC 2.0. Reliability testing yielded acceptable reliability coefficients for eight subscales. Hierarchical logistic regression provided further evidence of the instrument’s construct validity, with seven of the 10 dimensions found to be uniquely predictive of at least one of the three patient safety outcomes. Conclusion: The findings provide initial evidence of the content and construct validity of the Saudi-HSOPSC 2.0. Together, the findings provide evidence supporting five aspects of Messick’s (1980) view of unified validity. Future research should assess the validity of the Saudi instrument within a broader validation context and investigate the potential impact of included negatively worded items. With additional evidence supporting the psychometric properties of the Saudi-HSOPSC 2.0, Saudi administrators and nurse leaders can use it to assess the status of patient safety culture in their hospitals and inform future interventions aimed at improving patient safety and quality of care in Saudi hospital settings.11 0Item Restricted A Grounded Theory Investigation of Self-Identified Female Students’ Mental Health Perception, Mental Health Factors, and Help Seeking Behaviours(Western University, 2024) Alzaidi, Laila; Forchuk, Cheryl; Babenko-Mould, Yolanda; Booth, RichardThe purpose of this integrated-article dissertation was to explore self-identified female students’ understanding of mental health, mental health factors, and help-seeking behaviours. Young adults often face multiple stressors in their daily lives and must find ways to prevent, address, or overcome stressors that can lead to emotional and physical distress. University life can be more stressful because of greater responsibilities and independence during this age period. Increasingly, post secondary school students are recognized as an at-risk population for poor mental health. It is worth noting that female students experienced greater levels of stress compared to other genders. Poor mental health can contribute to poor academic performance and excessive alcohol consumption. Transition-aged youth (17-29 years) of all genders are particularly at risk of developing mental health problems, yet they are one of the least likely demographic groups to seek help. In a state of mental health, individuals are more prepared to take healthy risks, actively contribute to society, and gain life satisfaction. The undertaking for mental well-being is a common desire for oneself, students, and loved ones. However, limited research has been conducted about perceptions and attitudes of young adults, especially among female students, regarding mental health and help-seeking behaviours. A constructivist grounded theory study was conducted, and semi-structured interviews were undertaken between January and March 2023 with 22 self- identified female students who were enrolled in post-secondary programs at a university in Ontario, Canada. Participants shared their insights during in-depth individual interviews. The following eighteen themes emerged from students data during data analysis: psychological well-being, socioeconomic factors, social and societal influences on students’ well-being, holistic well-being perspectives, academic perspectives, career and financial perspectives, life and future perspectives, coping mechanisms, healthcare engagement challenges, psychological barriers, relational barriers, personal challenges, seeking professional and non-professional support, integrated support, self-reliance and self-help. The findings demonstrated that students’ advocacy for the promotion of mental health practices has a strong impact on their overall well-being.18 0Item Restricted Machine Learning Classififiers for Chronic Obstructive Pulmonary Disease Assessment Using Lung CT Data.(Western University, 2024-04-12) Alsurayhi, Halimah; Abbas, SamaniChronic Obstructive Pulmonary Disease (COPD) is a condition characterized by persistent inflammation and airflow blockages in the lungs, contributing to a significant number of deaths globally each year. To guide tailored treatment strategies and mitigate future risks, the Global Initiative for Chronic Obstructive Lung Disease (GOLD) employs a multifaceted assessment system of COPD severity, considering patient's lung function, symptoms, and exacerbation history. COPD staging systems, such as the high-resolution eight-stage COPD system and the GOLD 2023 three staging systems, have been later developed based on these factors. Lung Computed Tomography (CT) is becoming increasingly crucial in investigating COPD as it can detect various COPD phenotypes, such as emphysema, bronchial wall thickening, and gas trapping. Deep learning techniques show promise in leveraging CT imaging to assess the severity of COPD. This thesis uses lung CT data in conjunction with machine learning techniques to classify COPD patients according to these staging systems. For the eight-stage system, both Neural Network and Convolutional Neural Network (CNN) approaches were employed for classification. To develop the Neural Network model, features were extracted from lung CT scans at inspiration and expiration breathing phases, including lung air features and COPD phenotypes features. The CNN model utilized a single lung CT scan at the expiration phase. The GOLD 2023 three staging system involves training separate CNN models using lung CT scans at expiration to predict symptom levels and COPD exacerbation risk. In this thesis, in addition to models trained from scratch, Transfer Learning was also employed to develop models for the eight-stage COPD classification, Symptom level prediction, and exacerbation risk prediction. The developed classifiers demonstrate reasonably high classification performance, indicating their potential for deployment in clinical settings to enhance COPD assessment using image data.13 0Item Restricted Investigation of New Renewable Energy-based Multigeneration Systems for Saudi Arabia(Ontario Tech University, 2024-05-08) Altayib, Khalid; Dincer, IbrahimThis thesis explores three hybridized, large-scale solar thermal energy multigeneration systems: System 1 combines solar thermal energy with biomass, System 2 with geothermal, and System 3 with a petroleum coke and biomass blend. Each system provides power, heating, desalination, and other commodities. The thesis aims to develop energy system flowsheets integrating multiple technologies and assess their exergetic and economic benefits through case studies in KSA. Although the systems are of different kinds and scales, their economic parameters are found to be similar in terms of payback periods. System 1 achieves energy and exergy efficiencies of 50.4% and 45%, respectively. It generates annually 1040 GWh of electric power, 860 GWh of cogenerated heat, 80 GWh of refrigeration, 1100 tons of hydrogen, 26000 tons of chlorine gas, 11,600 tons of concentrated aqueous sodium hydroxide, 11,300 tons of ammonia, 1740 tons of aqueous urea, 905,000 m3 of fresh water. System 2 generates 700 GWh/year of power, 1200 GWh/year of heating, 27,100 tons/year of methanol, 130 million m3/year of fresh water, 42,500 tons/year of oxygen with efficiencies of 22% energy and 30% exergy. System 3 generates 1200 GWh/year of power, 690 GWh/year of heating, 12,700 tons/year of hydrogen, 19,300 tons/year of dried dates, 290,000 m3/year of fresh water and 80 GWh/year of cooling. The energy and exergy efficiencies of System 3 are 83.2% and 64%, respectively. For all systems, the chemical reactors are modelled using the Aspen Plus, which helps determine the best oxygen-to-biomass fraction in the gasifier as 15% at the turbine inlet temperature of 1500°C for System 1, the optimum methanol synthesis temperature in the range of 250°C-300°C for System 2, and results in 1.5 H2/C as the best molar ratio in hydro-gasifier to enhance the synthetic methane production rate for System 3. The thesis study underscores the potential of multigeneration and hybridization in improving the economics and ecology of renewable energy systems and offering insights applicable beyond the case studies explored.10 0