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The release of greenhouse gases (GHG) like methane plays a key role in driving the climate change. With the optimization of atmospheric chemistry climate models, the accuracy in predicting future scenarios is improved, which is an important factor in our efforts to mitigate climate change. The objective of this work is to introduce three methods for the quantification and adjustment of wrong or missing emissions in well-established GHG-inventories, which are used as input data for emissions in atmospheric chemistry transport or climate models. Beside a straight-forward upscaling method and a regridding method based on reported emission data, we present the WALLACE workflow, a new and efficient method to quantify GHG emissions based on satellite measurements. The overall goal of WALLACE is to highlight emission hotspots and it therefore includes spatiotemporal proxy data and a selection algorithm. For the North Sea as a show case region we apply WALLACE to quantify methane emission fluxes of oil and gas platforms. The adjusted emissions are implemented as pointsources into the ICOsahedral Nonhydrostatic model with Aerosols and Reactive Trace gases (ICON-ART) and idealized simulations are performed to compare the three methods with reference simulations to derive their impact on the spatial distribution of methane and its global and regional budget. For all three adjustment methods our model reveals a distribution of methane on the northern hemisphere and an effect on the European continent. For a quantification of the impact we evaluate the influence of the adjusted North Sea platform emissions on the radiative forcing. Additionally, we take a look at the anti-correlation between methane and its main sink in the atmosphere, the hydroxyl radical (OH), which is implemented as a simple OH-chemistry mechanism into the routines of the model. This work makes a new and innovative contribution to achieve an accurate quantification of environmentally harmful gases that drive man-made climate change.

Understanding how tropical forests respond to changes in the abiotic environment and human disturbance is critical for preserving biodiversity, mitigating climate change, and maintaining ecosystem services in the coming century. The lowland rainforests of Central Africa in particular are expected to lose 41% of present dense forest cover in the next 50 years to forest clearing, due in large part to forest loss resulting from the expansion of subsistence agriculture and logging. Deforestation also contributes a net increase in carbon dioxide to the atmosphere, exacerbating forest losses via increased tree mortality from drought, fire, and dispersal failure. Despite these grim circumstances, we know little about how Paleotropical tree communities are likely to respond to predicted changes in disturbance and climate. To evaluate the unique response of Afrotropical forests to changes in the abiotic environment and disturbance, I employ diverse data including species inventories, seed rain, species traits, remotely sensed historic climatic data, future climate predictions, and soil nutrient data collected from 134 1-ha plots arrayed in two large-scale observational experiments spanning the central African countries of Gabon and the Republic of Congo (Brazzaville). I then combine these diverse data using novel modeling methods to 1) determine the relative roles of climate and human disturbance on tree community composition, 2) quantify the relative effects of human disturbance and the abiotic environment on tree fecundity and seed dispersal, and 3) forecast future tree community change given predicted changes in climate. This work demonstrates that Afrotropical plant communities are more sensitive to human disturbance than to climate, with particular sensitivities to hunting and distance to village (a proxy for other human activities, including tree-cutting, gathering, etc.). These pressures have meaningful long-term effects on seed dispersal, increasing dispersal distances for animal dispersed seeds in disturbed forests. Finally, We forecast a 3 - 8% decrease in Afrotropical forest species richness by the end of the century, in contrast to the 30-50% loss of plant diversity predicted to occur with equivalent warming in the Neotropics.This work reveals that community forecasts are not generalizable across regions, and more representative studies are needed in understudied biomes like the Afrotropics. Nascent data sets, increased availability of high quality remote sensing data, and new statistical techniques capable of synthesizing these various data will help in further resolving the fate of the world’s ecosystems. This study serves as an important counterpoint to work done in the Neotropics by providing contrasting predictions for Afrotropical forests with substantially different ecological, evolutionary, and anthropogenic histories. Dissertation

The global agri-food system plays a critical role in food security and environmental issues. Increasing globalization has resulted in a complex international food system where production and consumption along the international supply chain can incorporate many geographically distinct regions. This interconnection means that it is difficult for any single producer or consumer to address these impacts. This thesis represents a step towards mapping the global food system from producers to consumers and offers several policy-relevant insights, especially in the national accounting of environmental footprints. Given that many drivers occur locally, but are traded globally, and that inter-regional differences in consumption are increasingly important, it is a natural next step to find approaches that can connect local impacts (production side) with global consumption (consumption side) through trade.Global spatially explicit multi-regional input-output (SMRIO) analyses can help identify hotspots of local production and associated social and environmental impacts driven by global consumption. In this thesis, I assess the use of SMRIO in the past and build a SMRIO model in three different case studies to assess its use. I use SMRIO models to investigate three critical issues (i.e. food security, biodiversity loss, and climate change) in the agri-food system.These sorts of assessments can help provide insights into how we might avoid catastrophic environmental problems in a globalized world. However, any of the benefits highlighted in these studies will require significant international action and collaboration. They will have to be sensitive to local conditions and the economic ramifications of rapid food transitions.

The potential to utilize lignin, which constitutes as much as 15-30% of the biomass, needs further evaluation. In the transition towards a bioeconomy, lignin has the potential to replace fossil-based phenols. Attempts to valorize the available technical lignins are ongoing; however, that lignin suffers from molecular heterogeneity. Accordingly, new process concepts, coined in the term lignin biorefineries, are required to obtain less heterogenic lignin with different properties and preserved molecular structure. In this study, a new lignin extraction concept was investigated, where the structural properties of lignin were preserved to a high degree using a physical protection strategy. The principle of preserving the lignin structure was based on a cyclic organosolv extraction concept. At first, a two-step concept was evaluated, where a hydrothermal extraction was performed to recover hemicellulose, followed by a cyclic organosolv extraction to obtain the lignin. Trend studies were performed for the individual cycles to gain a deeper understanding of how the lignin structure was affected by the cycles. To further investigate the method, chemometrics and design of experiment were used to gain knowledge about how different properties of lignin were affected by the extraction conditions and how the properties of lignin could be tailored. Based on the knowledge from the chemometric study and the observations from the two-step method, a refined one-step method was developed to obtain lignin with further improved analytical quality, i.e., up to 95% of the interunit linkages could be assigned for spruce lignin by heteronuclearsingle quantum coherence (HSQC) nuclear magnetic resonance (NMR)spectroscopy, 13C NMR and size exclusion chromatography (SEC). The universality of the method was investigated for different wood species, such as spruce and birch. The results indicate the applicability of the concept using different raw materials. The complex nature of lignin substrates conveys the need for robust analytic techniques. Herein, NMR studies were complemented by matrix-assisted laser desorption/ionization (MALDI) time of flight (TOF) mass spectrometry (MS) to provide new insights into molecular lignin populations with respect to reactivity during the organosolv extraction. Finally, a proof of concept for an application was investigated. The cyclic organosolv extracted lignin was used in a fundamental study on lignin nanoparticles (LNP), together with benchmark technical lignins, to gain knowledge about the role of the molecular structure in the LNP properties. It is suggested that the molecular structure of lignin plays an important role in determining the size and morphology of LNPs, opening possibilities to molecularly tailor LNP properties. Potentialen av att använda lignin, som utgör 15-30% av biomassan, behöver utvärderas ytterligare. I övergången till en bioekonomi finns potential för lignin att ersätta fossila fenoler. I denna kontext försöker man hitta ett värde för de tillgängliga tekniska ligninerna, men det finns utmaningar associerade med den molekylära strukturella heterogeniteten. Följaktligen behövs nya processkoncept, såsom lignin-bioraffinaderier, där man kan ta fram ett lignin med olika önskade egenskaper samt med en bevarad molekylstruktur. I denna studie utvecklades ett nytt koncept för att extrahera lignin, där ligninets strukturella egenskaper kunde bevaras i hög grad med hjälp av en fysisk skyddsstrategi. Principerna för att bevara ligninstrukturen baserades på ett cykliskt organosolv-extraktions-koncept. Först utvärderades en två-stegs koncept, där en hydrotermisk extraktion, för att extrahera ut hemicellulosa, efterföljdes av en cyklisk organosolvextraktion för att extrahera ut lignin. Trendstudier utfördes för de individuella cyklerna för att få en fördjupad förståelse av hur ligninstrukturen påverkades av cyklerna. För att ytterligare undersöka metoden användes kemometri och experimentell design för att öka kunskapen om hur olika extraktionsförhållanden påverkade egenskaper hos ligninet samt hur egenskaperna hos ligninet kunde skräddarsys.Genom den erhållna kunskapen från den kemometriska studien och den studerade trenden av två-stegsmetoden, undersöktes en kortare en-stegsmetod för att kunna erhålla ett lignin med ytterligare förbättrad analytisk kvalité, där upp till 95% av bindningarna kunde bestämmas för granlignin, karaktäriserat med heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance spectroscopy (NMR), 13C NMR och size exclusion chromatography (SEC). Metodens universalitet undersöktes för träslag med olika lignin-egenskaper som gran och björk. Resultaten indikerade tillämpbarheten av konceptet för olika råvaror. På grund av den komplexa naturen hos lignin finns ett behov av robusta analystekniker. För att möta detta kompletterades NMR-studier med matrix-assisted laser desorption/ionization (MALDI) time of flight (TOF) mass spectrometry (MS) analyser för att få nya insikter om olika molekylära ligninpopulationer samt för att öka kunskapen om ligninreaktiviteten under organosolv-extraktion. Slutligen gjordes en undersökning av hur det cykliska ligninet förhöll sig mot en applikation. Det cykliska organosolv-extraherade ligninet användes i en fundamental studie om lignin-nano partiklar (LNP), tillsammans med benchmark-tekniska ligniner, för att öka insikter om de molekylära egenskapernas roll för LNP-egenskaperna. Det har visat sig att den molekylära strukturen spelar en betydande roll för att bestämma storleken och morfologin hos LNP, vilket öppnar upp för möjligheter att molekylärt skräddarsy LNP-egenskaper. QC 2023-05-09Embargo godkänt av tf skolchef Amelie Eriksson Karlström via e-post 2023-05-09

Development of alternative fuel refineries, in order to improve global sustainability through increased biofuel production, has been increasingly supported by both government and private companies. Thermochemical processes such as hydrothermal liquefaction (HTL) and pyrolysis are leading technologies in this area. However, characterization, treatment, and reuse of aqueous by-products produced by such processes have received little attention. This dissertation is focused on aqueous phase characterization and catalytic advanced oxidation processing in novel microscale reactors. Novel char catalysts and improved process design were developed for efficient removal of organic contaminants. Small acids, cyclic pentenes, and carboxylic compounds such as phenol were initially identified. Model compounds were chosen based on these findings, and catalytic wet oxidation (CWO) processes in batch reactors conducted, in order to obtain reaction rate kinetics. The mechanism of compound oxidation was developed and shown through DFT analysis to be a production of hydroxyl free radicals ( ) in the presence of an oxidant and the N-doped char catalyst. The free radicals readily react with the dissolved organic compound, which was further confirmed with a FeO-N-doped char catalysts in a modified Fenton-like reaction system. In order to better develop a treatment processes which could integrate with a biorefinery, all process engineering experiments were conducted in a continuous solid-catalyzed microscale-based reactor utilizing the FeO-N-doped char catalyst. Time scale analysis was used for reactor geometry optimization in an effort to reduce diffusion time. The design led to a parallel plate reactor with channel depth of 500 microns. Thermochemical aqueous phases produced by pilot scale processes were characterized in detailed by extensive analytical methods. Traditional methods of spectroscopic analysis were limited in the ability to identify more complex oligomeric compounds and thus newer methods such as ICR-MS were utilized. The aqueous phases were successfully treated by the novel catalyst in the microreactor with removal of over 70% total organic carbon present at atmospheric pressure and at 90 °C. Some aqueous phase samples were more complex in nature however, successful decontamination was achieved. Catalytic wet oxidation processing in microscale-based reactors proves to be a plausible treatment option for process water in biorefineries.

Increasing energy consumption and concern for carbon emissions has boosted the demand for renewable energy production. The focus on renewable energy has gained much attention in wind, solar, hydro and wave power generations. Wave power has great potential due to its high energy density but there are challenges as well. This thesis addresses some of the challenges involved in the grid integration of wave energy and in maintaining power quality. In this thesis a grid connection of permanent magnet linear generator (PMLG) based wave energy converter (WEC) as a renewable energy source is evaluated at the Division of Electricity, Uppsala University. The grid impact of a wave energy park in terms of flicker, voltage variations and harmonic distortion at the grid-connection point are investigated extensively. The short-term flicker level generated by the WEC and a wave energy park (WEP) related to the rated WEP power and grid impedance angle at the PCC are evaluated. In this thesis, an improved control for hybrid energy storage is presented, which enhanced the efficiency and increased the battery life while smoothing the intermittent power from the WEP. The thesis, also, contributes to resolve the problem of inertia and power balance by integrating the DC-link capacitor in the control loop which reduce the size and cost of the components at the DC-link. The work presented in the thesis has contributed for the force control of the PMLG which is predicted and controlled by regulating the stator currents of the generator. A nonlinear, neural, control is evaluated and compared to a linear, proportional-integral, control. The results from the nonlinear control show the good agreement between the referenced and the generated currents. The reduced losses enhanced the accuracy of the system. A control and grid connection system for a WEC has been designed and installed. The thesis addresses the issue of power quality in low, steady and varying power flows of compliance with the grid code requirements. We havn't got the response from the opponent yet, It will be confirmed in a few days.

Cette thèse étudie les liens entre la finance et le dérèglement climatique. La première partie s’intéresse aux risques financiers induit par le changement climatique et les façons de s’y adapter. Ces risques sont désormais classiquement divisés en deux catégories : les risques physiques et de transition. C’est à ce dernier en particulier que nous nous intéressons. Nous verrons dans une première partie que la stratégie largement préconisée à intention des institutions financières aujourd’hui, l’établissement de scénarios, présente certains écueils difficilement surmontables dans leur mise en pratique. Ces scénarios sont en effet généralement globaux, souffrent d’incertitudes radicales et reposent de surcroît sur des hypothèses qui impliquent des modifications (réglementaires, légales, de comportement…) qui dépassent les institutions financières. Une fois cette première analyse menée, nous émettons ensuite une hypothèse quant aux hypothèses sous-jacentes qui ont pu donner lieu à ces recommandations. Dans une seconde partie, nous proposons une autre approche, fondée sur l’analyse risque-pays, qui prend en compte les dimensions sociologiques, géopolitique et technique de la transition. Deux études de cas sont menées pour illustrer notre propos, dont les conclusions sont ensuite généralisées.Enfin, nous étudions la façon dont les régulateurs pourraient s’emparer de notre proposition, et discuterons les autres possibilités de régulation aujourd’hui dans le débat public.La seconde partie s’intéresse au financement de la transition. Après un rapide survol des différentes estimations des besoins aujourd’hui disponible, nous présentons une proposition originale de garanties publiques internationales dont le but est de réorienter à grande échelle les flux financiers vers les besoins en investissements bas carbone. Enfin, nous présentons les instruments de la finance durable privée aujourd’hui disponibles, et soulignons l’importance des processus de certification aux moyens d’un modèle. This thesis studies the links between finance and climate change.The first part focuses on the financial risks induced by climate change and the ways to adapt to them. These risks are now classically divided into two categories: physical and transition risks. It is the latter in particular that we are interested in.We will see in the first part that the strategy widely recommended for financial institutions today, the establishment of scenarios, presents certain pitfalls that are difficult to overcome in their implementation. These scenarios are generally global, suffer from radical uncertainties and are based on assumptions that imply changes (regulatory, legal, behavioral, etc.) that go beyond the financial institutions. After this initial analysis, we then hypothesize about the underlying assumptions that may have led to these recommendations.In the second part, we propose another approach, based on country risk analysis, which takes into account the sociological, geopolitical and technical dimensions of the transition. Two case studies are conducted to illustrate our point, whose conclusions are then generalized.Finally, we study how regulators could take up our proposal, and discuss the other possibilities of regulation currently in the public debate.The second part focuses on the financing of the transition. After a quick overview of the different estimates of the needs available today, we present an original proposal for international public guarantees whose aim is to redirect financial flows on a large scale towards low-carbon investment needs.Finally, we present the private sustainable finance instruments available today, and highlight the importance of certification processes using a model.

Includes bibliographical references. Number of sources in the bibliography: 111. Thesis (Ph. D.) -- University of Cyprus, Faculty of Engineering, Department of Electrical and Computer Engineering, 2023. The University of Cyprus Library holds the printed form of the thesis. Η αυξανόμενη διείσδυση των ανανεώσιμων πηγών ενέργειας (ΑΠΕ) στο ηλεκτρικό σύστημα εισάγει πολλαπλές προκλήσεις ασφάλειας, αξιοπιστίας και αποδοτικότητας, κυρίως λόγω της ανεξέλεγκτης παραγωγής ΑΠΕ. Τα συστήματα αποθήκευσης ενέργειας (ΣΑΕ) αποτελούν μια αναδυόμενη τεχνολογία που μπορεί να αντισταθμίσει τα αρνητικά αποτελέσματα της παραγωγής ΑΠΕ μέσω της βέλτιστης διαχείρισης της ενέργειας που παράγεται από τις ΑΠΕ. Ο κύριος στόχος αυτής της διδακτορικής διατριβής αφορά την επίλυση προβλημάτων βελτιστοποίησης που σχετίζονται με τη διαχείριση κατανεμημένων πηγών ενέργειας σε ηλεκτρικά συστήματα με υψηλή διείσδυση ΑΠΕ και ΣΑΕ. Τέτοια προβλήματα είναι δύσκολο να επιλυθούν καθώς απαιτούν γρήγορες και βέλτιστες ή υψηλής ποιότητας λύσεις και συχνά συνδέονται με ανακρίβειες μοντελοποίησης και αβεβαιότητα στην παραγωγή ενέργειας από ΑΠΕ. Σε αυτό το πλαίσιο, έχουν μελετηθεί τα ακόλουθα προβλήματα: (α) η βελτιστοποίηση γενικών προβλημάτων διαχείρισης ενέργειας σε συστήματα ηλεκτρικής ισχύος που περιλαμβάνουν μη-κυρτά μοντέλα των ΣΑΕ, (β) η διαχείριση ενέργειας από φωτοβολταϊκά και συστήματα μπαταριών σε ενεργά δίκτυα διανομής, (γ) η διαχείριση ενέργειας ενός συστήματος αποθήκευσης με σφόνδυλο για την μείωση των κορυφών φορτίου στα ηλεκτρικά δίκτυα και (δ) η βελτιστοποίηση της στρατηγικής υποβολής προσφορών από παραγωγούς ΑΠΕ στις αγορές ηλεκτρικής ενέργειας χρησιμοποιώντας συστήματα μπαταριών. Για την επίλυση αυτών των προβλημάτων, έχουν αναπτυχθεί μέθοδοι βελτιστοποίησης που δημιουργούν γρήγορες και υψηλής ποιότητας εφικτές λύσεις. Οι προσομοιώσεις και τα πειραματικά αποτελέσματα επιβεβαιώνουν την αποτελεσματικότητα των προτεινόμενων μεθόδων επίλυσης των εξεταζόμενων προβλημάτων, διασφαλίζοντας την ασφαλή, αξιόπιστη και αποδοτική λειτουργία του συστήματος ηλεκτρικής ενέργειας. The increasing penetration of renewable energy sources (RESs) into the power system introduces several safety, reliability and efficiency challenges, mainly due to the uncontrollability of RES. Energy storage systems (ESSs) constitute an emerging technology that can compensate the negative effects of intermittent RES generation by optimally managing the energy produced by RES. The main aim of this PhD thesis regards the solution of optimization problems associated with the management of distributed energy resources in power systems with high RES and ESS penetration. Such problems are challenging because they require fast and optimal or close-to-optimal solutions, and often involve modelling inaccuracies and RES uncertainty. In this context, four problems are considered: (i) optimization of general energy management problems in power systems involving non-convex ESS models, (ii) energy management of photovoltaic and battery storage systems in active distribution grids, (iii) energy management of a flywheel storage system for peak shaving applications, and (iv) stochastic optimization of the bidding strategy of RES producers in electricity markets considering battery degradation. To address these problems, custom optimization methods that yield high-quality and fast solutions have been developed. Simulation and/or experimental results validate the quality of the developed solution approaches for the considered problems in ensuring the safe, reliable, and efficient operation of the power system. KIOS Research and Innovation Centre of Excellence (KIOS CoE)

The proper atrium design can be an optimum way for providing maximum users’ satisfaction and energy efficiency throughout different seasons. In a hot and humid climate, using a buffer zone as the atrium caused a thermal performance problem. One of the problematic issues can conclude as fluctuation in indoor conditions which is caused discomfort hours. This research investigates the thermal performance of the atrium building in a hot and humid climate based on different design parameters. Furthermore, this research deals with the ASHRAE (2018) - ISO 7730 - EN 25251 standards of energy performance and users’ thermal comfort for the atrium in single-floor, medium-rise, and high-rise office buildings. It applies different proportions of office and atrium volumes in finding the optimum design and assessing the different atrium window opening ratios, internal condition systems, and atrium orientations throughout a year. The EDSL Tas software was used for dynamic thermal simulations. The goal of this study to propose the optimum atrium and office volumes for buildings in a hot and humid climate based on thermal performance in the different seasons. The findings of this research illustrate that when the internal condition of the building is natural ventilation, the single-floor and medium-rise atrium buildings with an atrium proportion 1/2 of the office proportion with south-east (single-floor) and center (medium-rise) atrium placements had maximum occupants’ satisfaction (users’ comfort). However, when the internal condition of the building was mechanically conditioned (basic air-conditioning) and the atrium proportion was 1/3 and 1/4 of the office proportion, especially with the center (single-floor) and north-east (medium-rise) atrium placement, it had an acceptable internal comfort throughout the year. Furthermore, the high-rise atrium building with a natural internal condition and an atrium proportion 1/4 of the office proportion in the north-east placement, and the mechanically conditioned (basic air-conditioning) 1/3 atrium proportion of the office proportion in the center placement had more internal thermal comfort than other dynamic simulation scenarios during the year. Keywords: Atrium Volume, Atrium Orientation, Naturally Conditioned Building, Mechanically Conditioned Building, Hot and Humid Climate, EDSL Tas. ÖZ: Atriyum tasarımı ile maksimum ısıl konfor ve enerji verimliliği yüksek olan, tüm mevsimlerde kullanılabilen sürdürülebilir bina tasarlayabiliriz. Bu tezin kapsamında ASHRAE (2018), ISO 7730, EN 25251 uluslararası standartları kullanılarak tek kat, orta ve yüksek katlı ofis binaları incelenmiştir. Optimum tasarım için farklı pencere açılış oranları, iç mekan koşulları, farklı atriyum yönledirmeleri ve farklı ofis-atriyum oranları yıl boyunca EDSL Tas yazılımı ile bulunması bu tezin amacıdır. Bu araştırmanın bulguları, doğal havalandırma kapsamında tek ve orta katlı ofis binasının yarı hacmi atriyum olduğunda ve güney-doğu yönü ile maksimum kullanıcı konforu sağlanabilmektedir. Mekanik havalandırma kullanıldığında ise 1/3 ile 1/4 atriyum ile ofis oranı ve merkezi atriyum-tek katlı bina, kuzey-doğu ile orta katlı bina olduğunda maksimum kullanıcı memnuniyeti sağlandığı görülmüştür. Ayrıca, doğal havalandırmalı yüksek katlı bina için ofis hacminin 1/4 oranında kuzey-doğu yönünde atriyum tasarımı ile 1/3 oranında mekanik havalandırmalı merkezi konumu olan atriyum tasarımı olduğunda her iki senaryoda yıl bazında tüm diğer simülasyonlar içerisinde en fazla ısıl konfor sağlamıştır. Anahtar Kelimeler: Atriyum Hacmi, Atriyum Oryantasyonu, Doğal Havalandırılmış Bina, Mekanik Havalandırılmış Bina, Sıcak ve Nemli Iklim, EDSL Tas. Doctor of Philosophy in Architecture. Institute of Graduate Studies and Research. Thesis (Ph.D.) - Eastern Mediterranean University, Faculty of Architecture, Dept. of Architecture, 2020. Supervisor: Assoc. Prof. Dr. Zafer Alibaba