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The thesis describes the development of a computational tool that allows sophisticated analysis and design of flue gas cleaning technologies for thermal treatment of waste. The assessment of a technological composition of the process in terms of energy consumption, temperature of the flue gas stream and ensuring the fulfilment of emission limits allows estimating the influence of flue gas cleaning system on parameters of an up-to-date waste incinerator. The work is based on an already created computational system. Its output will be integrated into a software system with a user-friendly interface. Creation of the computational system is based on the performed research in the given area. The work presents sets of operational values and relationships describing current technologies used to reduce harmful emissions in the flue gas from thermal treatment of waste.

Solar photovoltaic (PV) parks have proliferated all over the world as a result of the growing demand for electricity, and especially electricity from renewables. As these parks become larger and complex, it becomes increasingly important to develop accurate and efficient mathematical models that can be used to predict their performance and optimize their design. The inverter is an essential component of a solar PV system that converts the DC power generated by the solar panels into AC power that can be used by the grid or by local loads. This research paper presents a comparative study between a pre-existing reference model and a mathematical model, developed specifically for predicting the AC power output of photovoltaic systems. In addition, a hybrid model is included for comparative analysis. The performance of each model was evaluated using real-world data installed at Glava Energy Centre in Hillringsberg, Sweden. The reference and hybrid models showed similar trends in their calculated versus actual values, but the hybrid model outperformed the reference model slightly. The actual power values were found to be similar to the simulated values in all three models. However, the mathematical model was more specific and sensitive to the inverter under consideration, resulting in a comprehensive and accurate representation of the inverter's behaviour. The models take into account the inverter's characteristics, as well as environmental elements like temperature and solar irradiance that affect its performance. The results showed that the mathematical model outperformed the other models in terms of accuracy and reliability, achieving an R2 score of 0.9226, 0.9936, 0.9789, and 0.9736 for the months of February, April, July, and October, respectively. The mathematical model also had the lowest root mean square error (RMSE) and mean absolute error (MAE) values compared to the other models. The results of this study demonstrate the value of mathematical modelling in the design and optimization of solar PV parks and provide a framework for the development of more complex models in the future.

Problem solving at the crossroads between chemistry and mathematics presents significant challenges for students at all levels of education. This licentiate thesis aims to enhance our understanding of such problem solving, with a focus on how university students approach problems in the context of chemical kinetics. The thesis is based on two papers. The video data analysed in these papers were collected from problem-solving sessions where second-year chemistry students worked in pairs to solve tasks centred around a key concept in chemical kinetics. The first paper aimed to develop a framework suitable for analysing problem solving at the interface of chemistry and mathematics. Deductive and inductive analysis of the collected video data resulted in the extended mathematical modelling cycle (MMC). This empirically derived framework offers a fine-grained picture of the processes and resources at play during problem solving in chemical kinetics, suggesting that students: (1) engage in a range of (sub)processes beyond those typically outlined in the classical MMC; and (2) employ extra-mathematical resources (EMRs) in all stages of the MMC. The EMRs can be divided into chemical and other resources. While chemical resources are essential in translating chemical information into mathematical relationships, they also play a crucial role during mathematical work, offering guidance to the mathematical operations. The purpose of the second paper was to further characterise the nature and roles of other resources. Findings suggest that other resources can be divided into: implicit models of results, explicit examples from experience, and superficial procedural resources. Analysing their roles in problem solving revealed that implicit models primarily influence students’ ideas of where they are going, while explicit examples and superficial procedural resources provide a basis of strategies for how to get there.

Catalytic hydrotreating (HDT) is a mature process technology practiced in the petroleum refining industries to treat oil fractions for the removal of impurities (such as sulfur, nitrogen, metals, asphaltene). Hydrotreating of whole crude oil is a new technology and is regarded as one of the more difficult tasks that have not been reported widely in the literature. In order to obtain useful models for the HDT process that can be confidently applied to reactor design, operation and control, the accurate estimation of kinetic parameters of the relevant reaction scheme are required. This thesis aims to develop a crude oil hydrotreating process (based on hydrotreating of whole crude oil followed by distillation) with high efficiency, selectivity and minimum energy consumption via pilot plant experiments, mathematical modelling and optimization. To estimate the kinetic parameters and to validate the kinetic models under different operating conditions, a set of experiments were carried out in a continuous flow isothermal trickle bed reactor using crude oil as a feedstock and commercial cobaltmolybdenum on alumina (Co-Mo/¿-Al2O3) as a catalyst. The reactor temperature was varied from 335°C to 400°C, the hydrogen pressure from 4 to10 MPa and the liquid hourly space velocity (LHSV) from 0.5 to 1.5 hr-1, keeping constant hydrogen to oil ratio (H2/Oil) at 250 L/L. The main hydrotreating reactions were hydrodesulfurization (HDS), hydrodenitrogenation (HDN), hydrodeasphaltenization (HDAs) and hydrodemetallization (HDM) that includes hydrodevanadization (HDV) and hydrodenickelation (HDNi). An optimization technique is used to evaluate the best kinetic models of a trickle-bed reactor (TBR) process utilized for HDS, HDAs, HDN, HDV and HDNi of crude oil based on pilot plant experiments. The minimization of the sum of the squared errors (SSE) between the experimental and estimated concentrations of sulfur (S), nitrogen (N), asphaltene (Asph), vanadium (V) and nickel (Ni) compounds in the products, is used as an objective function in the optimization problem using two approaches (linear (LN) and non-linear (NLN) regression). The growing demand for high-quality middle distillates is increasing worldwide whereas the demand for low-value oil products, such as heavy oils and residues, is decreasing. Thus, maximizing the production of more liquid distillates of very high quality is of immediate interest to refiners. At the same time, environmental legislation has led to more strict specifications of petroleum derivatives. Crude oil hydrotreatment enhances the productivity of distillate fractions due to chemical reactions. The hydrotreated crude oil was distilled into the following fractions (using distillation pilot plant unit): light naphtha (L.N), heavy naphtha (H.N), heavy kerosene (H.K), light gas oil (L.G.O) and reduced crude residue (R.C.R) in order to compare the yield of these fractions produced by distillation after the HDT process with those produced by conventional methods (i.e. HDT of each fraction separately after the distillation). The yield of middle distillate showed greater yield compared to the middle distillate produced by conventional methods in addition to improve the properties of R.C.R. Kinetic models that enhance oil distillates productivity are also proposed based on the experimental data obtained in a pilot plant at different operation conditions using the discrete kinetic lumping approach. The kinetic models of crude oil hydrotreating are assumed to include five lumps: gases (G), naphtha (N), heavy kerosene (H.K), light gas oil (L.G.O) and reduced crude residue (R.C.R). For all experiments, the sum of the squared errors (SSE) between the experimental product compositions and predicted values of compositions is minimized using optimization technique. The kinetic models developed are then used to describe and analyse the behaviour of an industrial trickle bed reactor (TBR) used for crude oil hydrotreating with the optimal quench system based on experiments in order to evaluate the viability of large-scale processing of crude oil hydrotreating. The optimal distribution of the catalyst bed (in terms of optimal reactor length to diameter) with the best quench position and quench rate are investigated, based upon the total annual cost. The energy consumption is very important for reducing environmental impact and maximizing the profitability of operation. Since high temperatures are employed in hydrotreating (HDT) processes, hot effluents can be used to heat other cold process streams. It is noticed that the energy consumption and recovery issues may be ignored for pilot plant experiments while these energies could not be ignored for large scale operations. Here, the heat integration of the HDT process during hydrotreating of crude oil in trickle bed reactor is addressed in order to recover most of the external energy. Experimental information obtained from a pilot scale, kinetics and reactor modelling tools, and commercial process data, are employed for the heat integration process model. The optimization problem is formulated to optimize some of the design and operating parameters of integrated process, and minimizing the overall annual cost is used as an objective function. The economic analysis of the continuous whole industrial refining process that involves the developed hydrotreating (integrated hydrotreating process) unit with the other complementary units (until the units that used to produce middle distillate fractions) is also presented. In all cases considered in this study, the gPROMS (general PROcess Modelling System) package has been used for modelling, simulation and parameter estimation via optimization process. / Tikrit University, Iraq

La fibrillation auriculaire (FA) figure parmi les arythmies les plus courantes chez les patients âgés et dont l’incidence augmente avec l’âge. La compréhension des mécanismes liant les caractéristiques tissulaires et le risque de la FA demeure centrale pour l’optimisation du traitement. Les alternances de la durée du potentiel d’action (APD) dans le tissu cardiaque ont été depuis peu documentées comme l’un des phénomènes qui facilitent la FA. Généralement, la FA est associée à de courtes périodes de stimulation électrique. Récemment, la FA a été observée aux longues périodes de stimulation chez les patients atteints de la FA chronique (FAc). Les mécanismes sous-jacents aux alternances d’APD aux longues périodes de stimulation ne sont pas totalement déterminés. En partant d’un modèle mathématique avec le remodelage électrophysiologique associé à la FAc d’un myocyte auriculaire humain, notre objectif était de premièrement identifier ces mécanismes ainsi, nous avons réalisé une analyse de la sensibilité des alternances aux changements des paramètres du modèle. Dix-huit (18) paramètres associés au remodelage de la FA ont été mis à l’échelle entre 30% et 200% de leur valeur de base. Ensuite, nous avons stimulé le tissu à partir de l’électrode de stimulation pendant des périodes de stimulation (CL) comprise entre 700 ms et 350 ms. Les alternances de la durée du potentiel d’action et du calcium intracellulaire (Cai) ont été quantifiées par la suite au point d’enregistrement. On a validé que les alternances d’APD et de Cai étaient significatives seulement pour le changement du paramètre kiCa qui représente la constante d’inactivation des récepteurs ryanodines (RyR). Sachant que ce sont les alternances discordantes qui constituent un substrat pour la FA, nous avons en second lieu, validé la formation des alternances spatialement discordantes aux longues périodes de stimulation lorsque les alternances étaient occasionnées par la diminution de kiCa. Lorsque les alternances discordantes étaient entraînées par l’hétérogénéité de l’inactivation des RyR, le motif des alternances dépendait des conditions initiales de cette hétérogénéité. Nous avons par la suite déterminé les facteurs dynamiques qui modulaient l’apparition des alternances d’APD et de Cai aux périodes de stimulation pour lesquelles les alternances se sont manifestées. On a trouvé que pour notre modèle de FAc avec la diminution de kiCa, les alternances étaient pilotées par le cycle calcique alors que pour le modèle FAc de base, les alternances résultaient des interactions entre le cycle membranaire et calcique. Ces expériences nous ont permis de développer un modèle itéré qui prenait en compte les variables des cycles membranaires, calciques ainsi que le couplage entre ces cycles. L’analyse des données a révélé que le modèle itéré devait être constitué des variables dépendantes suivantes : calcium stocké dans le réticulum sarcoplasmique (SR), calcium cytoplasmique et la durée du potentiel d’action. Notre modèle itéré a pu reproduire les caractéristiques de la dynamique du système représenté par le tissu auriculaire humain avec le remodelage du FAc stimulé périodiquement. / Atrial fibrillation (AF) is one of the most common arrhythmias in elderly patients, and its incidence increases with age. Understanding the mechanisms linking tissue characteristics and the risk of AF remains central to optimising treatment. Action potential duration (APD) alternans in cardiac tissue have recently been documented as one of the phenomena that facilitate AF. Typically, AF is associated with short periods of electrical stimulation. Recently, AF has been observed at long pacing periods in patients with chronic AF (AFc). The mechanisms underlying APD alternans at long pacing periods are not fully determined. Using a mathematical model with the electrophysiological remodeling associated with AFc in a human atrial myocyte, our aim was first to identify these mechanisms and then to analyse the sensitivity of the alternans to changes in the model parameters. Eighteen (18) parameters associated with AF remodelling were scaled between 30% and 200% of their baseline value. The tissue was then paced from the stimulation electrode at pacing periods (CL) between 700 ms and 350 ms. Action potential duration and intracellular calcium (Cai) alternans were subsequently quantified at the recording point. APD and Cai alternans were found to be significant only for the change in the kiCa parameter, which represents the ryanodine receptor (RyR) inactivation constant. Knowing that it is the discordant alternans that constitute a substrate for AF, we secondly validated the formation of spatially discordant alternans at long pacing periods when the alternans were caused by the decrease in kiCa. When the discordant alternans were driven by heterogeneity in RyR inactivation, the pattern of alternans depended on the initial conditions of this heterogeneity. We then determined the dynamic factors that modulated the appearance of APD and Cai alternans at the pacing periods for which the alternans occurred. We found that for our AFc model with the decrease in kiCa, the alternans were driven by the calcium cycle, whereas for the basic AFc model, the alternans resulted from interactions between the membrane and calcium cycles. These experiments enabled us to develop an iterated model that considered the variables of the membrane and calcium cycles, as well as the coupling between these cycles. Analysis of the data revealed that the iterated model should consist of the following dependent variables: calcium load in the sarcoplasmic reticulum (SR), cytoplasmic calcium and the duration of the action potential. Our iterated model was able to reproduce the characteristics of the dynamics of the system represented by human atrial tissue with the electrophysiological remodeling associated with AFc paced periodically.

The imminent threat of global catastrophe due to climate change gets more real by each passing year. The Aviation trade association, IATA, claims that Aviation accounts for approximately 2% of the Greenhouse Gases (GHG) caused by human activities, and 3.5% of the total Radiative Forcing. With continuous increase in Aviation industry and subsequent drop in fossil fuel prices, these numbers are only expected to up with time. In Addition, these numbers do not include the effects of altitude of emission and many environmentalists believe that the number for some pollutants could be at least 2-3 times larger than IATA estimates. This rising concern engages the Aviation industry to investigate possible methods to alleviate their environmental impact.  The first part of this thesis provides a framework to support Airlines in monitoring their current environmental footprint during the process of scheduling. This objective is realised by developing a robust system for estimating the fuel consumed (ergo quantity of major Greenhouse Gases emitted) by a particular fleet type operating a certain leg, which is then employed in a Fleet Assignment (FA) Operation to reduce emissions and increase the Contribution. An emissions estimation model for Turbojet Aeroplane fleets is created for Industrial Optimizers AB’sMP2 software. The emissions estimation model uses historic fuel consumption data provided by ICAO for a given fleet type to estimate the quantity (in kg) of environmental pollutants during the Landing and Takeoff operation (below 3000 ft) and the Cruise, Climb and Descent operation (above 3000 ft).  The second part of this thesis concerns with assigning monetary weights to the pollutant estimates to calculate an emission cost. This emission cost is then added to MP2’s Fleet Assignment’s objective function as an additional Operational cost to perform a Contribution maximization optimization subjected to the legality constraints. The effects of these monetary weights levied on the results of Fleet Assignment are studied, and utilizing curve-fitting and mathematical optimization, monetary weights are estimated for the desired reduction in GHG emissions.  Finally, a recursive algorithm based on Newton-Raphson method is designed and tested for calculating pollutant weights for untested schedules. / Det omedelbara hotet om en global katastrof pga klimatförändringar blir mer och mer tydligt för varje år som går. IATA, den internationella flyghandelsorganisationen, hävdar att flyget står för runt 2% av växthusgaserna (GHG) som kommer från människans aktiviteter, och 3.5% av den totala avstrålningen. Med den kontinuerliga tillväxten av flygindustrin och prisminskningar av fossila bränslen så förväntas dessa andelar att öka. Dessutom så inkluderar inte dessa siffror effekten av att utsläppen sker på hög höjd, och många miljöaktivister tror att siffrorna för vissa utsläpp kan vara åtminstone 2-3 gånger högre än IATAs uppskattningar. Denna växande oro motiverar flygindustrin till att undersöka metoder för att begränsa dess miljöpåverkan.  Den första delen av denna rapport ger ett ramverk för att hjälpa flygbolag med att bevaka deras aktuella miljöavtryck under schemaläggningsprocessen. Detta mål realiseras genom att utveckla ett robust system för att uppskatta bränsleförbrukningen (och därmed kvantiteten av växthusgasutsläpp) av en specifik flygplanstyp på en given etapp, som sedan kan användas för att allokera flygplanstyper för att minska utsläppen och bidra till att förbättra miljön. En modell för att uppskatta utsläpp för flottor av turbojetflygplan har skapats för Industrial Optimizers AB programvara MP2. Modellen för att uppskatta utsläppen baseras på historiska data om bränsleförbrukning som tillhandahållits av ICAO för en given flygplanstyp som använts för att uppskatta kvantiteten (i kg) av föroreningar vid start (under 3000 fot) och vid sträckflygning, stigning och inflygning (över 3000 fot). Den andra delen av denna rapport handlar om att bestämma monetära vikter till föroreningsskattningarna för att beräkna utsläppskostnader som ska användas i MP2 s målfunktion för allokering av flygplanstyper. Detta ger en ytterligare driftskostnad att beakta i optimeringen för att få med miljöaspekterna och tillåtna lösningar. Effekten som dessa monetära vikter har på resultaten från optimeringen studeras, och genom att använda kurvanpassning och matematisk optimering, de monetära vikterna anpassas för att få den önskade minskningen i växthusgasutsläpp. Slutligen så har en rekursiv algoritm, baserad på Newon-Raphsons metod, designats och testats för att beräkna utsläppsvikter för scheman som inte använts för att beräkna vikterna

The technical feasibility of gasoline and diesel range hydrocarbons production through oligomerisation of olefins, starting from biomass with the intermediary steps of gasfication, water-gas shift reaction and syngas-to-olefins synthesis was investigated, through mathematical modelling and simulation on Matlab. The model for the gasifier was based on minimisation of Gibbs free energy and its results showed that higher carbon efficiencies could be achieved at lower pressures and steam inlet, and more inlet energy, by pre-heating the gasifying agents. The water-gas shift reactor was used to increase the ratio of hydrogen to carbon monoxide from the gasifier, before entering the syngas-to-olefins process. A 1-D model was employed to determine the concentration, temperature, and pressure profiles in the reactor. High inlet pressure and temperature were shown to be beneficial, by requiring smaller reactors for the desired ratios to be reached. Experimental data from scientific literature was used for empirical modelling of the Fischer-Tropsch reactor. Partial pressure of CO and H2 amounting to 1 bar, high temperature and H2/CO showed better production of the low olefins. A reaction mechanism and accordingly, rate equations were developed and employed in a plug-flow type reactor model, calculating the concentration profile of the olefins up to C20. High pressures were favourable for the production of heavier fractions, while elevated temperatures showed to cause more cracking of heavy hydrocarbons and consequently, less conversion. Based on the results of individual reactors, an integrated process flow diagram was suggested and optimised for maximum production of low olefins to the oligomerisation reactor (C2-4). The optimisation showed overall carbon efficiency of the process to be around 20%. The reason for this was associated with the choice of catalyst in the FTO process, due to its high selectivity to carbon dioxide. / Den tekniska genomförbarheten av bensin- och dieselproduktion genom oligomerisering av olefiner, från biomassa via förgasning, vatten-gasförskiftsreaktion och syngas-till-olefiner syntes undersöktes genom matematisk modellering och simulering på Matlab. Förgasningsmodellen baserades sig på Gibbs energi minimisering. Ju mindre förgasningstryck desto högre uppnås koleffektivitet. Vatten-gasskift reaktorn användas för att anpassa väte/kolmonoxid förhållande från förgasningsreaktorn till syngas till olefiner rektorn. En 1-D modell utvecklades och beräknade reaktorns koncentrationer, temperatur och tryckprofiler. Högre inlopps tryck och temperaturer leder till mindre reaktorer.   Experimentella data från vetenskaplig litteratur användes för att modellara Fischer-Tropsch reaktorn (syngas till olefiner). Partialt tryck av CO och H2 lika med 1 bar, hög temperatur och H2 / CO visade högre produktion av lätta olefiner. En reaktionsmekanism och följaktligen hastighetsekvationer utvecklades för oligomerisering och användades i en pluggflödesreaktor. Modellen beräknade koncentrationer profiler av olefiiner upp till C20.Högre tryck producerar tyngre fraktioner (diesel) medan högra temperaturer främjar krakning. Baserat på resultaten från enskilda reaktorer föreslogs ett integrerat processflödesdiagram och optimerades för maximal produktion av låga olefiner till oligomeriseringsreaktorn (C2-4). Optimeringen visade att den totala koleffektiviteten i processen var cirka 20%. Anledningen till detta var förknippat med valet av katalysator i FTO-processen på grund av dess höga selektivitet för koldioxid.

Evaporation plays an important role in the water balance on a different spatial scale. However, its direct and indirect measurements are globally scarce and accurate estimations are a challenging task. Thus the correct process approximation in modelling of the terrestrial evaporation plays a crucial part. A physically based 1D lumped soil–plant–atmosphere model (BROOK90) is applied to study the role of parameter selection and meteorological input for modelled evaporation on the point scale. Then, with the integration of the model into global, regional and local frameworks, we made cross-combinations out of their parameterization and forcing schemes to show and analyse their roles in the estimations of the evaporation. Five sites with different land uses (grassland, cropland, deciduous broadleaf forest, two evergreen needleleaf forests) located in Saxony, Germany, were selected for the study. All tested combinations showed a good agreement with FLUXNET measurements (Kling–Gupta efficiency, KGE, values 0.35–0.80 for a daily scale). For most of the sites, the best results were found for the calibrated model with in situ meteorological input data, while the worst was observed for the global setup. The setups' performance in the vegetation period was much higher than for the winter period. Among the tested setups, the model parameterization showed higher spread in performance than meteorological forcings for fields and evergreen forests sites, while the opposite was noticed in deciduous forests. Analysis of the of evaporation components revealed that transpiration dominates (up to 65 %–75 %) in the vegetation period, while interception (in forests) and soil/snow evaporation (in fields) prevail in the winter months. Finally, it was found that different parameter sets impact model performance and redistribution of evaporation components throughout the whole year, while the influence of meteorological forcing was evident only in summer months.

Adenosine-3′, 5′-cyclic monophosphate (cAMP) produced by adenylate cyclases (ADCYs) is an established key regulator of cell homoeostasis. However, its role in cell cycle control is still controversially discussed. This study focussed on the impact of soluble HCO3− -activated ADCY10 on cell cycle progression. Effects are quantified with Bayesian inference integrating a mathematical model and experimental data. The activity of ADCY10 in human umbilical vein endothelial cells (HUVECs) was either pharmacologically inhibited by KH7 or endogenously activated by HCO3−. Cell numbers of individual cell cycle phases were assessed over time using flow cytometry. Based on these numbers, cell cycle dynamics were analysed using a mathematical model. This allowed precise quantification of cell cycle dynamics with model parameters that describe the durations of individual cell cycle phases. Endogenous inactivation of ADCY10 resulted in prolongation of mean cell cycle times (38.7 ± 8.3 h at 0 mM HCO3− vs 30.3 ± 2.7 h at 24 mM HCO3−), while pharmacological inhibition resulted in functional arrest of cell cycle by increasing mean cell cycle time after G0/G1 synchronization to 221.0 ± 96.3 h. All cell cycle phases progressed slower due to ADCY10 inactivation. In particular, the G1-S transition was quantitatively the most influenced by ADCY10. In conclusion, the data of the present study show that ADCY10 is a key regulator in cell cycle progression linked specifically to the G1-S transition.