AUB ScholarWorks

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Archaeological Museum 3
Asfari Institute for Civil Society and Citizenship 84
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Center For Advanced Mathematical Sciences 21

Recent Submissions

A Nature-Based Solutions Planning Framework for Arid Cities
Jaroush, Sarah; Abunnasr, Yaser; Zurayk, Rami; McPhearson, Timon; MSES; Department of Landscape Design and Ecosystem Management; Faculty of Agricultural and Food Sciences
As aridity continues to increase in the world, with nearly 300 large cities projected to face increasing water scarcity issues by 2050, Nature-based Solutions (NbS) offer a unique multifunctional approach to addressing the severe environmental pressures in these contexts. While existing NbS planning frameworks provide a robust structure and guidance for city-planners, there is a gap in tailoring these frameworks to the context of hot arid cities, given the different environmental and socio-economic conditions. Against this backdrop, this research seeks to answer how can existing NBS planning frameworks be contextualized to address the specific challenges in hot arid cities? The methodology used to answer this question employed a qualitative analysis of existing NbS, Urban Planning and Sustainable Urban Planning frameworks, coupled with a cross-case comparative analysis of implemented NbS interventions in arid cities. Findings reveal a dominance in greening models in NbS, leaning towards addressing visible short-term stressors – like addressing heat stress using increased vegetation– with little consideration to underlying environmental stressors – like limited water supply. This mismatch is exacerbated by limited research engagement to adapt NbS interventions to the local ecosystem processes. The study also reveals how interactions between lead, funding and implementing actors impact NbS design and deployment across different scales and spatial contexts, with city-wide interventions skewed towards centralized governance systems, and smaller-scale interventions comprising higher modes of stewardship and participation with the local community. By synthesizing insights from 94 global case studies and existing planning literature, the study offers a Contextualized NbS Planning Framework (C-NbS-F) for hot arid cities, and a prototype decision-support tool to help planners shift from visible "greening" symptoms to underlying hydrological limits. Lastly, this thesis contributes to enhancing urban resilience against progressing aridification due to climate change, by generating transferable lessons and strategies for a more water-scarce future.
Accelerating Graph Isomorphism with GPU-Parallel Canonical Labeling
Dbouk, Rana; El Hajj, Izzat; Mouawad, Amer E.; Safa, Haidar; MS; Department of Computer Science; Faculty of Arts and Sciences
Graph isomorphism (GI) is a fundamental problem in computer science with applications across many domains, including chemistry for molecular comparison, pattern recognition in image analysis, and motif discovery in biological networks. Despite its importance, GI remains computationally hard on certain graph classes, where canonical labeling search trees can grow exponentially. This work presents a CUDA based parallelization of the canonical labeling algorithm (nauty), leveraging coarse grained parallelism across the search tree and fine-grained parallelism within nodes using GPU thread blocks. This strategy aims to achieve substantial speedups on structurally hard instances by enabling concurrent exploration of the search space, potentially making canonical labeling practical for graph classes previously considered infeasible. Extensive experimental evaluation on a diverse set of benchmark graph families demonstrates that GPU parallelization substantially reduces runtime, particularly on hard instances. On highly symmetric graph families, the proposed method achieves speedups ranging from approximately 4× to over 10,000× relative to our sequential baseline, and up to several thousand times relative to nauty. In such cases, early pruning enabled by parallel exploration eliminates large portions of the search tree. In contrast, graph families for which the explored search tree remains nearly identical across implementations exhibit consistent speedups of around 18×–23× over the sequential implementation and approximately 3× over nauty. The observed gains are mainly due to parallelizing the core computation within each search node rather than reductions in the search space. Overall, these results demonstrate that GPU-based parallel canonical labeling is both feasible and effective, delivering substantial performance improvements while preserving the algorithmic behavior of classical tools.
Post-War Construction Demolition Wastes Recycling and Reusing in Sustainable Practices
Tawbe, Hadi; 202380985; Mabsout, Mounir; Maalouf, Elsa; Srour, Issam; El-Khatib, Helmi; ME; Department of Civil and Environmental Engineering; Maroun Semaan Faculty of Engineering and Architecture
One of the major consequences of the recent war on Lebanon in 2023-2024 is the vast destruction of infrastructure and habitations in various towns and villages, mainly in South Lebanon, the Beqaa region, and the Southern Suburb of Beirut. The full or partial demolitions that ensued resulted in massive amounts of construction rubbles and debris of all kinds which, for the most part, are still lying on site. Solutions are now urgently awaited, and some are being proposed to manage the waste debris, ranging from large-scale to local interventions that are still under investigation. The American University of Beirut (AUB) in partnership with South for Construction (SFC) - “الجنوب للإعمار” -, and with the engagement of the affected communities, are herewith proposing a practical and rapid solution for the recycling/reuse of the construction demolition wastes (CDW) that will have a valuable outcome to impact positively on the built environment, the financial benefits, and the social fabric of communities. Technically, the solution that is here being explored aims at repurposing the waste debris to be recycled and used as justifiable construction materials in the reconstruction/ retrofitting of the demolished/damaged habitations. In particular, the process to be adopted considered the crushing of the debris to transform into construction aggregate sizes, then to be used as a partial substitute for conventional aggregates consisting of natural fine sands and coarse gravels. Such an environmentally sound process will inherently contribute to the reduction of natural resource depletion, and thus present itself as one viable and sustainable construction practice. In the present circumstances, and for practicable and efficient reasons, the waste debris were kept assembled on site “as is”, thus not sorted by material constituents and sizes. In this research, rubbles from 5 demolished sites in South Lebanon from Zraryieh and Ansar and the Southern Suburb of Beirut from Laylaki, Bir El Abed, and Sayed Hadi Highway were identified and studied. Then samples of these materials were taken to the crushing site, where part of each sample was crushed once and the other part was crushed twice. Then these samples were investigated in the labs and their physical, mechanical, and chemical properties validated as substitute construction aggregates (fine and coarse). Multiple tests in stages and phases were conducted similarly per site to evaluate the physical, mechanical, and chemical properties of the crushed materials (Stage 1), with the aim to reach the optimal cementitious and concrete mixes from preliminary testing for each site, with the crushed aggregates at the two levels/sizes and considering the various replacement percentages considered (Stage 2). And using this optimal mix, further required tests on the concrete samples were conducted to assert the soundness and validity of the crushed debris or alternate aggregates as viable sustainable construction materials (Stage 3). The current research and thesis focused on the technical aspect of CDW. This is complemented with other parallel work which has been or is being concurrently conducted on CDW management, economic feasibility, and policy advocacy with the proper authorities.
Understanding Anjar’s Vulnerability and Capacity to Adapt to Evolving Climate Risks
Andonian, Sevada; 202472618; Jurdi, Mey; Mumtaz, Ghina; Dhaini, Hassan; MSES; Interfaculty Graduate Environmental Sciences Program; Faculty of Health Sciences
Climate change poses increasing risks to human health and livelihoods, especially in rural areas with limited institutional and environmental health infrastructure. In Lebanon, evidence on how community climate vulnerability and health intersect remain minimal, limiting the effectiveness of interventions and local adaptation planning. This study examines whether the health profile of a town reflects its community’s vulnerability to climate change. A cross-sectional mixed-methods assessment was conducted combining the Livelihood Vulnerability Index adapted to the Inter-Governmental Panel on Climate Change framework (LVI–IPCC), the WHO Healthy Villages framework, and WHO climate vulnerability checklists for primary healthcare facilities. Household-level data were collected from 241 households across Anjar’s six neighborhoods and outskirts using structured surveys. Stakeholder interviews informed the Healthy Villages assessment and the climate vulnerability of the town’s two primary healthcare centers which were evaluated using WHO checklists covering workforce, WASH, energy, and infrastructure domains. Results indicate that Anjar exhibits moderate overall climate vulnerability with an overall score of -0.056, characterized by relatively high exposure (0.492) and sensitivity (0.257) that are partially offset by strong adaptive capacity (0.711). Strong adaptive capacity is largely rooted in strong social networks and high climate change knowledge, which have scores of 0.783 and 0.735 respectively. However, the town’s health profile demonstrated that significant environmental health shortcomings persist, particularly in WASH and Waste Management. Both primary healthcare centers demonstrated high vulnerability to droughts, floods, heatwaves, and wildfires, reflecting limited preparedness and institutional capacity to respond to climate-related health shocks. The findings demonstrate that the health profile of a town both reflects and shapes climate vulnerability, mediated by social, environmental, and institutional conditions. Integrating the LVI–IPCC with the WHO Healthy Villages framework provides a scalable and adaptable approach for determining climate–health vulnerabilities in Lebanese rural contexts.
UiO-66 for the Removal of Tetracycline Antibiotic: Do We Need Modulators?
Balaa, Fawzi; 201703132; Ahmad, Mohammad; Zeaiter, Joseph; Hmadeh, Mohamad; ME; Baha and Walid Bassatne Department of Chemical Engineering and Advanced Energy; Maroun Semaan Faculty of Engineering and Architecture
Metal organic frameworks (MOFs) have been widely applied in water treatment studies to remove organic pollutants by either adsorption or photocatalysis. The chemical and structural properties of the MOF are controlled by various parameters including the initial precursors used and their concentrations, the method of preparation, and the addition of modulators during synthesis. In this work, the effect of modulation of UiO-66 on its final properties as well as its adsorption and degradation efficiencies for the removal of tetracycline antibiotic from water was studied. UiO-66 was synthesized with seven different acidic modulators: formic, acetic, trifluoroacetic, benzoic, bromoacetic, decanoic, and dodecanoic acids, each tested at the highest reported in the literature and at half that value. In total, 14 modulated UiO-66 samples and a non-modulated sample were prepared and extensively characterized by PXRD, BET, XPS, FTIR, TGA, UV–Vis, and SEM. The influence of modulator acidity, chain length, and steric bulk on crystallinity, porosity, and defect formation was systematically investigated. Adsorption and degradation tests under visible light revealed that modulators can either enhance or deteriorate the performance of UiO-66. In particular, trifluoroacetic-acid-modulated UiO-66 (TFA18) exhibited the highest adsorption efficiency (93\% after 300 min), which was 60\% higher than that of non-modulated UiO-66. Photocatalytic degradation under a 100 W white LED or real solar irradiation showed negligible dependence on modulation, as the band-gap energy of UiO-66 remained largely unaffected. These observations were confirmed using statistical analysis conducted in JMP. Modulation of UiO-66 is therefore recommended for adsorption applications, whereas non-modulated UiO-66 is preferable for photocatalytic degradation when using mesoporous MOFs. These findings highlight modulation as a versatile strategy for optimizing MOF preparation to enhance performance in environmental remediation applications.