Opin vísindi
Opin vísindi er varðveislusafn vísindaefnis og doktorsritgerða í opnum aðgangi á vegum íslenskra háskóla og Landsbókasafns Íslands - Háskólabókasafns.
Opinn aðgangur að rannsóknaniðurstöðum er í samræmi við 10. gr. laga nr. 3/2003 um opinberan stuðning við vísindarannsóknir sem og kröfur innlendra og erlendra rannsóknasjóða. Markmiðið með opnum aðgangi er að niðurstöður rannsókna séu aðgengilegar sem flestum óhindrað og án endurgjalds á rafrænu formi. Vistun í varðveislusafninu er varanleg og ætlað að tryggja aðgang að vísindaefni íslenskra háskóla í opnum aðgangi um ókomna tíð. Varðveislusafnið Opin vísindi er tengt við rannsóknagáttina IRIS og rannsóknaniðurstöður í opnum aðgangi sem eru skráðar í IRIS eru um leið vistaðar og gerðar aðgengilegar til framtíðar í varðveislusafninu. Með því að safna þessu efni saman í eitt safn verður aðgangur að því einfaldur og þægilegur fyrir alla sem vilja kynna sér það og geta þannig notið þess öfluga vísindastarfs sem fram fer í háskólum landsins.
Varðveislusafnið er OpenAIRE / OpenAIREplus samhæft og samrýmist kröfum sem gerðar eru um birtingu rannsóknaniðurstaðna úr verkefnum sem styrkt eru úr evrópsku rannsóknaáætlununum FP7 og H2020.
Varðveislusafnið notar opna hugbúnaðinn DSpace.
Opinn aðgangur að rannsóknaniðurstöðum er í samræmi við 10. gr. laga nr. 3/2003 um opinberan stuðning við vísindarannsóknir sem og kröfur innlendra og erlendra rannsóknasjóða. Markmiðið með opnum aðgangi er að niðurstöður rannsókna séu aðgengilegar sem flestum óhindrað og án endurgjalds á rafrænu formi. Vistun í varðveislusafninu er varanleg og ætlað að tryggja aðgang að vísindaefni íslenskra háskóla í opnum aðgangi um ókomna tíð. Varðveislusafnið Opin vísindi er tengt við rannsóknagáttina IRIS og rannsóknaniðurstöður í opnum aðgangi sem eru skráðar í IRIS eru um leið vistaðar og gerðar aðgengilegar til framtíðar í varðveislusafninu. Með því að safna þessu efni saman í eitt safn verður aðgangur að því einfaldur og þægilegur fyrir alla sem vilja kynna sér það og geta þannig notið þess öfluga vísindastarfs sem fram fer í háskólum landsins.
Varðveislusafnið er OpenAIRE / OpenAIREplus samhæft og samrýmist kröfum sem gerðar eru um birtingu rannsóknaniðurstaðna úr verkefnum sem styrkt eru úr evrópsku rannsóknaáætlununum FP7 og H2020.
Varðveislusafnið notar opna hugbúnaðinn DSpace.
Nýlega bætt við
Exploring Novel Catalysts for Efficient Electroreduction of CO₂ to e-Fuels
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026-10-07) Awais, Muhammad; Younes Abghoui; Faculty of Physical Sciences (UI); Raunvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)
Current global energy and environmental challenges can be viewed as the interaction of three connected factors: the use of fossil fuels, carbon dioxide (CO2) emissions, and global warming. The global energy landscape remains largely dependent on fossil fuels, leading to substantial CO2 emissions and disturbing the climatic equilibrium. Nonetheless, one promising strategy for addressing this challenge is to regard CO2 as a resource, thereby converting the challenge into an opportunity for ecological restoration through the use of CO2 for the production of sustainable fuels. This approach turns CO2 into eco-friendly, value-added compounds, promoting greenhouse gas reduction and sustainable energy development. An effective solution to these limitations can possibly be addressed through chemical physics and electrochemistry, particularly through the implementation of the electrochemical CO2 reduction reaction (CO2RR), which converts CO2 into several single and multi-carbon (C1/C2 products) compounds, including carbon monoxide, formic acid, methanol, methane, methanediol, ethylene, ethane, and ethanol. This process can be readily integrated with current renewable energy infrastructure, enabling the coupling of CO2 conversion with sustainable power sources and therefore storing renewable energy as chemical products. However, their practical application remains limited by the low catalytic activity, poor selectivity, and broad product distribution of conventional metal catalysts. In several instances, these catalysts primarily convert CO2 to only CO or formic acid with relative simplicity, whereas the synthesis of more reduced or multi-carbon compounds requires more energy input and often exhibits restricted efficiency. Hence, the electrochemical CO reduction reaction (CORR) may provide essential solutions to tackle the current challenges in the field of CO2RR. Thus, this Ph.D. thesis is dedicated to the exploration of these two research directions to identify more efficient and selective reaction pathways for sustainable carbon transformation via both CO2RR and CORR.
To the best of our knowledge, this thesis presents the first systematic computational investigation of transition metal carbonitrides (TMCNs) for electrochemical CO2RR and CORR. A rigorous computational framework using density functional theory (DFT) within the Vienna Ab initio Simulation Package (VASP) was applied to analyze these surfaces for both CO2RR and CORR. This theoretical study examined 33 different catalytic surfaces, eleven TMCNs in (100), (111), and (110) facets, to predict their catalytic activity towards the formation of C1 and C2 products. Moreover, comprehensive computational evaluations were performed to assess the behavior of these different TMCNs in diverse electrochemical environments with pre-adsorbed CO surface coverage. The catalytic performance was investigated using the conventional and the Mars-van Krevelen (MvK) mechanisms and over 2000 reaction pathways to identify the most thermodynamically favorable routes and predict the best TMCN candidate(s) for efficient carbon conversion and management. In the catalytic activity analysis, TMCN(110) was identified as offering the highest activity for both CO2RR and CORR via the MvK mechanism. In conventional pathways, TMCN(111) was found to be the most active for CO2RR, while TMCN(100) was the best for CORR, and TMCN(111) was inactive toward conventional CORR.
Overall, this dissertation provides a comprehensive theoretical assessment of TMCNs and offers computationally grounded predictions for their potential use in converting carbon into green fuels, thereby addressing important environmental and sustainable energy concerns.
Postpartum post-traumatic stress symptoms and mother-infant bonding : A population-based cross-sectional study
(2025-09) Sigurðardóttir, Valgerður Lísa; Hákonardóttir, Guðrún Anna; Arnardóttir, Stefanía Birna; Lýðsdóttir, Linda Bára; Swift, Emma Marie; Department of Psychology
Objective: Postpartum post-traumatic stress symptoms are associated with negative outcomes for women's mental health and may disrupt the development of the mother–infant bond. However, previous research has reported inconsistent findings. The aim was to examine the predictive role of postpartum post-traumatic stress symptoms on mother–infant bonding 6 to 12 weeks after birth in a population-based sample. Method: This population-based cross-sectional study was conducted in 2022 and included 598 women 6 to 12 weeks postpartum. Postpartum post-traumatic stress symptoms were measured using the City Birth Trauma Scale, and mother–infant bonding was assessed with the Postpartum Bonding Questionnaire. Linear regression analysis was used to examine the association between post-traumatic stress symptoms and mother–infant bonding, adjusting for maternal age, parity, mode of birth, educational level, and depressive symptoms. Results: The mean score on the City Birth Trauma Scale was 8.4, and 5.5 on the Postpartum Bonding Questionnaire. A total of 1.5 % of participants scored above the cut-off for significant bonding difficulties. Higher levels of postpartum post-traumatic stress symptoms were significantly associated with greater bonding difficulties (B = 0.380, p < 0.005). This association remained significant after adjustment for background variables and depressive symptoms (B = 0.113, p = 0.007). Primiparity, higher educational attainment, and depressive symptoms were also significantly associated with bonding difficulties (p < 0.05). Conclusion: The findings suggest that postpartum post-traumatic stress symptoms negatively affect the development of the mother–infant bond. A targeted screening of post-traumatic stress symptoms and bonding difficulties is recommended, followed by appropriate support in postpartum care.
Modelling CSRBB under regulatory guidelines
(2025-09) Segal, Maxime; Kristjánsson, Kristján Rúnar; Björnsson, Björn Hrannar; Department of Engineering
The European Banking Authority (EBA) provides limited standardization for Credit Spread Risk in the Banking Book (CSRBB), delegating its assessment to individual financial institutions. This has led to significant variation in how CSRBB guidelines are interpreted and applied across the banking sector. This study investigates how to model plausible but unlikely credit spread shocks using Principal Component Analysis (PCA), hypothesizing that systemic risk dominates fluctuations across government and corporate bonds. The model aligns with EBA requirements and provides insights to strengthen risk management frameworks.
Feature Selection in Healthcare Datasets : Towards a Generalizable Solution
(2025-09) Maruotto, Ida; Ciliberti, Federica Kiyomi; Gargiulo, Paolo; Recenti, Marco; Department of Engineering
Background and objective: The increasing dimensionality of healthcare datasets presents major challenges for clinical data analysis and interpretation. This study introduces a scalable ensemble feature selection (FS) strategy optimized for multi-biometric healthcare datasets aiming to: address the need for dimensionality reduction, identify the most significant features, improve machine learning models’ performance, and enhance interpretability in a clinical context. Methods: The novel waterfall selection, that integrates sequentially (a) tree-based feature ranking and (b) greedy backward feature elimination, produces as output several sets of features. These subsets are then combined using a specific merging strategy to produce a single set of clinically relevant features. The overall method is applied to two healthcare datasets: the biosignal-based BioVRSea dataset, containing electromyography, electroencephalography, and center-of-pressure data for postural control and motion sickness assessment, and the image-based SinPain dataset, which includes MRI and CT-scan data to study knee osteoarthritis. Results: Our ensemble FS approach demonstrated effective dimensionality reduction, achieving over a 50% decrease in certain feature subsets. The new reduced feature set maintained or improved the model classification metrics when tested with Support Vector Machine and Random Forest models. Conclusion: The proposed ensemble FS method retains selected features essential for distinguishing clinical outcomes, leading to models that are both computationally efficient and clinically interpretable. Furthermore, the adaptability of this method across two heterogeneous healthcare datasets and the scalability of the algorithm indicates its potential as a generalizable tool in healthcare studies. This approach can advance clinical decision support systems, making high-dimensional healthcare datasets more accessible and clinically interpretable.
The Complex and Long-Duration 2002 April 18 Mw 6.7 Near-Trench Earthquake in the Guerrero Seismic Gap, Mexico
(2025-08-01) Flores-Ibarra, Ketzallina; Hjörleifsdóttir, Vala; Singh, Shri Krishna; Iglesias, Arturo; Pérez-Campos, Xyoli; Ito, Yoshihiro; Department of Engineering
The seismic behaviour of the near-trench plate interface of the Guerrero seismic gap and other segments of the Mexican subduction zone is likely to play a critical role in the seismic and tsunami hazard of the region. In this context, a detailed study of the near-trench 2002 April 18 Mw 6.7 earthquake that occurred about 55 km off the coast of Guerrero and generated a small tsunami attains particular importance. From an analysis of the teleseismic P waves and S waves, local recordings and aftershock distribution, we find that the rupture most likely began at a subducted seamount, propagated unilaterally towards NW, parallel to the trench for ∼54-58 km and a duration of ∼68-70 s. The moment rate function is highly rugged, with two dominant pulses separated by about 50 s. Although relatively small in magnitude, the earthquake has all the characteristics of a tsunami earthquake: the slip occurs very close to the trench, the rupture speed is slow (∼1 km s-1), the high-frequency radiation is deficient, and, in common with tsunami earthquakes, the moment-scaled radiated energy is low (ER/M0 = 1.45 × 10-6). We confirm that the duration of the event (∼70 s) is extraordinarily long compared to that expected from scaling relations (∼12.8 s), consistent with it being the most anomalous of all the events studied in the last 40 yr. Our results support a conditionally stable upper 15 km of the plate interface in the region reported from recent offshore seismic observations.
Flokkar í Opnum vísindum
Veldu flokk til að skoða.
- University of Iceland
- University of Akureyri
- Bifröst University
- Hólar University College
- IRIS
- Agricultural University of Iceland
- National and University Library of Iceland
- Iceland University of the Arts