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1
Muresan, Gheorghe. "Using document clustering and language modelling in mediated information retrieval." Thesis, Robert Gordon University, 2002. http://hdl.handle.net/10059/623.
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Our work addresses a well documented problem: users are frequently unable to articulate a query that clearly and comprehensively expresses their information need. This can be attributed to the information need being too ambiguous and not clearly defined in the user's mind, to a lack of knowledge of the domain of interest on the part of the user, to a lack of understanding of a retrieval system's conceptual model, or to an inability to use a certain query syntax. This thesis proposes a software tool that emulates the human search mediator. It helps a user explore a domain of interest, learn its structure, terminology and key concepts, and clarify and refine an information need. It can also help a user generate high-quality queries for searching the World Wide Web or other such large and heterogeneous document collections. Our work was inspired by library studies which have highlighted the role of the librarian in helping the user explore her information need, define the problem to be solved, articulate a formulation of the information need and adapt it for the retrieval system at hand in order to get information. Our approach, mediated access through a clustered collection, is based on an information access environment in which the user can explore a relatively small, well structured, pre-clustered document collection covering a particular subject domain, in order to understand the concepts encompassed and to clarify and refine her information need. At the same time, the user can ostensively indicate clusters and documents of interest so that the system builds a model of the user's topic of interest. Based on this model, the system assists and guides the user's exploration, or generates `mediated queries' that can be used to search other collections. We present the design and evaluation of WebCluster, a system that reifies the concept of mediated retrieval. Additionally, a variety of mediation experiments are presented,which provide guidelines as to which mediation strategies are more appropriate for different types of tasks. A set of experiments is presented that evaluate document clustering's capacity to group together topical documents and support mediation. In this context we propose and experimentally test a new formulation for the cluster hypothesis. We also look at the ability of language models to convey content, to represent topics and to highlight specific concepts in a given context. They are also successfully applied to generate flexible, task-dependent cluster representatives for supporting exploration through browsing and respectively searching. Our experimental results show that mediation has potential to significantly improve user queries and consequently the retrieval effectiveness.
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Majin, Wodu. "Mathematical modelling of GPCR-mediated calcium signalling." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/12451/.
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Ca2+ is an important messenger which mediates several physiological functions, including muscle contraction, fertilisation, heart regulation and gene transcription. One major way its cytosolic level is raised is via a G-protein coupled receptor (GPCR)- mediated release from intracellular stores. GPCR’s are the target of approximately 50% of all drugs in clinical use. Hence, understanding the underlying mechanisms of signalling in this pathway could lead to improved therapy in disease conditions associated with abnornmal Ca2+ signalling, and to the identification of new drug targets. To gain such insight, this thesis builds and analyses a detailed mathematical model of key processes leading to Ca2+ mobilisation. Ca2+ signalling is considered in the particular context of the M3 muscarinic receptor system. Guided by available data, the Ca2+ mobilisation model is assembled, first by analysing a base G-protein activation model, and subsequently extending it with downstream details. Computationally efficient designs of a global parameter sensitivity analysis method are used to identify the key controlling parameters with respect to the main features of the Ca2+ data. The underlying mechanism behind the experimentally observed, rapid, amplified Ca2+ response is shown to be a rapid rate of inositol trisphosphate (IP3) formation from Phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis. Using the same results, potential drug targets (apart fromthe GPCR) are identified, including the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) and PIP2. Moreover, possible explanations for therapeutic failures were found when some parameters exerted a biphasic effect on the relative Ca2+ increase. The sensitivity analysis results are used to simplify the process of parameter estimation by a significant reduction of the parameter space of interest. An evolutionary algorithm is used to successfully fit the model to a significant portion of the Ca2+ data. Subsequent sensitivity analyses of the best-fitting parameter sets suggest that mechanistic modelling of kinase-mediated GPCR desensitisation, and SERCA dynamics may be required for a comprehensive representation of the data.
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Long, E. A. G. "Modelling microdomain-mediated protein sorting in immunological signalling." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1355593/.
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Compartmentalisation is a fundamental feature of biological systems. The organism as a whole can be seen as a single compartment of the wider ecosystem. At lower scales, we observe biological processes compartmentalised into organs, cells, cell subtypes and organelles. In the highly complex discipline of immunology, compartmentalisation is key in order to respond e ciently to foreign antigens and to maintain the balance between immunity and tolerance. Recent studies have raised questions about the role of compartmentalisation in lipid membranes, from the relatively well described immunological synapse, to the smaller, more transient lipid raft or microdomain. This thesis asks whether, and how, microdomains could in uence the formation of small receptor complexes. Speci cally, we approach what appears to be a simple surface reaction-di usion problem from multiple viewpoints: explicitly simulating particle di usion using a probabilistic pixel-based model, and deriving a deterministic relation between spatial parameters and the timecourse of chemical concentrations throughout the model space. We also show the equivalence between the predictions of these two models, further supporting the validity of our approach. We also embed the results of our model output in an existing model of the immunological response in order to determine the downstream consequences of enhanced receptor organisation. The study gives a broader understanding of the mechanisms involved in microdomain-mediated protein sorting, highlights the degree of interdependence on multiple spatial and chemical parameters and suggests numerous avenues for future research.
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Kelly, Catherine Elizabeth. "Mathematical modelling of macrophage-mediated therapy in cancer." Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268496.
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Pierce, Nicholas. "Modelling vitamin Bâ†1â†2 - cobalt mediated cyclisation reactions." Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367417.
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Slingerland, Martin Jacob (Marc), and University of Lethbridge Faculty of Arts and Science. "Modelling the auxin-mediated vein formation system in plant leaves." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2007, 2007. http://hdl.handle.net/10133/673.
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The plant hormone auxin is involved in a wide range of developmental phenomena in
plants. It carries out many of its effects through a signalling network involving the regulation
of specific genes, including those involved in its own polar transport between cells.
These transporters are able to be redistributed between cell faces, causing the asymmetric
auxin transport that is a key requirement for the formation of vein patterns in leaves.
In this thesis I describe the development of a biochemical kinetics-based model of auxin
signalling and transport in a single cell, which displays biologically plausible responses
to auxin application. The single-cell model then serves as the basis for a multicell model
of auxin-mediated vein formation at a very early stage of leaf formation in Arabidopsis
thaliana.<br>ix, 73 leaves : ill. ; 29 cm.
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Forster, Samantha. "In silico modelling of transporter-mediated xenobiotic flux through cells." Thesis, University of Surrey, 2010. http://epubs.surrey.ac.uk/844458/.
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Drug transporters are increasingly recognised as important drivers in the pharmaco- and toxico-kinetic characteristics of therapeutic agents. Preclinical assays are used to determine the effects of transport on the pharmacokinetics and toxicology of a new compound during drug development. However in vitro cell systems and in vivo animal models often give erroneous results due to the differential expression of important proteins within them. In silico models have been employed to help bridge the gap and make more accurate predictions for drug disposition and metabolism; however such models have not incorporated transport kinetics or induction by nuclear receptors. Many current models also use a reductionist approach, whereby a multiple component pathway is described by a single mathematical term, reducing the ability of the simulation to determine the effects of single parameters. The first aim of this research was therefore to assess the differences in drug transporter expression in a variety of human and rat hepatocellular systems compared to liver. RT-PCR and protein analysis of drug transporter levels in vitro and in vivo showed huge differences, with influx transporters generally being under-expressed and efflux transporters over-expressed in vitro compared to in vivo. These differences were more pronounced at the RNA level than protein level. Transporter expression was also shown to be dynamic, changing over time in culture and in response to nuclear receptor activation. The second aim was to generate an in silico model of cellular response to stimuli, using a whole-cell approach to investigate system dynamics. Kinetics for the lifecycle rhodamiae-123 were determined in vitro and incorporated into an in silico model of human hepatocyte disposition that could accurately simulate outcomes in a variety of cell types and make useful predictions of drug disposition from in vitro results. In conclusion, the in silico model revealed that drug transporter expression and activity may affect drug disposition, with uptake processes presenting as the fragile node in the network. Such a model would be useful in the early stages of drug development to improve extrapolation between biological systems and to identify the likely consequences of different expression levels and species inhibition and induction.
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Howitt, Ryan. "Stochastic modelling of repeat-mediated phase variation in Campylobacter jejuni." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/52218/.
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It is of interest to determine how populations of bacteria whose genes exhibit an ON/OFF switching property (phase variation) evolve over time from an initial population. By statistical analysis of two in vitro experimental Campylobacter jejuni datasets containing 28 genes assumed to be phase variable, we find evidence of small networks of genes which exhibit dependent evolutionary behaviour. This violates the assumption that the genes in these datasets do not interact with one another in the way they mutate during the division of cells, motivating the development of a model which attempts to explain evolution of such genes with factors other than mutation alone. We show that discrete probability distributions at observation times can be estimated by utilising two stochastic models. One model provides an explanation with mutation rates in genes, resembling a Markov chain under the assumption of having a near infinite population size. The second provides an explanation with both mutation and natural selection. However, the addition of selection parameters makes this model resemble a non-linear Markov process, which makes further analysis less straight-forward. An algorithm is constructed to test whether the mutation-only model can sufficiently explain evolution of single phase variable genes, using distributions and mutation rates from data as examples. This algorithm shows that applying this model to the same phase variable genes believed to show dependent evolutionary behaviour is inadequate. We use Approximate Bayesian Computation to estimate selection parameters for the mutation with selection model, whereby inference is derived from samples drawn from an approximation of the joint posterior distribution of the model parameters. We illustrate this method on an example of three genes which show evidence of dependent evolutionary behaviour from our two datasets.
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Han, Hyungjin Civil & Environmental Engineering Faculty of Engineering UNSW. "Mechanisms and modelling of sonochemically-mediated free radical degradation of contaminants." Awarded by:University of New South Wales. Civil & Environmental Engineering, 2009. http://handle.unsw.edu.au/1959.4/43485.
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Hazardous and recalcitrant pollutants in the environments have led to a great many environmental issues these days. Many researchers have focused on the approaches to treatment of these pollutants which contaminate environments such as soil, surface and groundwater. As an advanced oxidation processes (AOPs), sonolysis which is the oxidation technology involving the use of ultrasonic irradiation, has proven to be successful for the treatment and remediation of contaminated environments. In this thesis, hydrogen peroxide formation and formic acid degradation by ultrasonic irradiation of well-characterised solutions are described under various conditions in order to determinate reaction mechanism by which peroxide degradation and contaminant degradation occur. The effect of gas properties and frequency on hydrogen peroxide and formic acid degradation are examined. Experimental results obtained are analyzed in light of the reactions occurring. Successful mathematical modeling of the result s obtained confirms that, for the most part, hydrogen peroxide and formic degradation occur by free radical generation within bubbles with subsequent transfer of these radicals to the bubble-water interface where the majority of the degradation occurs. The effect of Fe(II) addition which can lead to Fenton reactions in the bulk solution are also investigated. Experimental and model results show that the heterogeneous reactions can enhance the degradation of formic acid in the presence of Fe(II). Oxidation of phenol by ultrasonic irradiation under a variety of initial conditions and solution environments is also described and validated by a simple kinetic model. The model developed will be useful for improving our understanding of free radicals behaviour and the interplay between free radical generation and contaminant degradation.
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Chapman, Timothy Peter. "Morphological and neural modelling of the orthopteran escape response." Thesis, University of Stirling, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391494.
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Lin, Congping. "Mathematical modelling for bidirectional motor-mediated motility in a fungal model system." Thesis, University of Exeter, 2012. http://hdl.handle.net/10036/3869.
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In Ustilago maydis hyphae, bidirectional transport of early endosomes (EEs) occurs on microtubules (MTs) that have plus and minus ends. The transport is powered by kinesin-3 towards the plus ends of MTs and dynein towards the minus ends. Experiments show an accumulation of dynein at the MT plus end. To investigate the mechanism of this accumulation, I consider two extended asymmetric simple exclusion principle (ASEP) models for the bidirectional transport of dynein in this thesis. In the simpler two-lane model, collision between opposite-directed motors is excluded whereas the more sophisticated 13-lane model takes into account that the MT usually consists of thirteen protofilaments. The presence of multi protofilaments allows dynein to avoid collision with kinesin by changing protofilaments, a behaviour that has been experimentally described. Both models are supplied by quantitative data obtained in U. maydis by live cell imaging and suggest that the stochastic behaviour of dynein can account for half of dynein motors in the accumulation at the MT plus end. Moreover, for the two-lane model, by using a mean field approximation, I give an analytical approximation for the accumulation size which shows linear dependence on the flux. In contrast, this dependence is nonlinear in the 13-lane model and appears to be associated with a phase transition leading to a "pulsing state". Accompanied experimental studies have shown that U. maydis contains a complex MT array and that kinesin-3 moves early endosomes along antipolar MT bundles. In order to better understand the bidirectional EE motility, I extend the two-lane ASEP to model bidirectional transport along an antipolar MT bundle. In this model, the MTs are coupled at minus ends where organelles can switch MTs on which they move. By a mean-field approximation and numerical simulations, I investigate how the switching affects phases of density profiles as well as the type of motor that dominates the active transport in the bundle.
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Nachev, Vladislav Nikolaev. "Cognition mediated floral evolution." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2014. http://dx.doi.org/10.18452/16869.
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Von Schmetterlingen und Bienen bis Kolibris und Fledermäusen hat sich eine große Vielfalt von Tieren auf Blumennektar als Nahrung spezialisiert. Die Nektareigenschaften der vielen Pflanzenarten scheinen den Bedarf des Hauptbestäubers widerzuspiegeln, z.B. produzieren die von größeren Tieren bestäubten Pflanzen in der Regel auch größere Mengen an Nektar. Diese Übereinstimmung deutet darauf hin, dass Nektarmerkmale in Erwiderung auf die Auswahlkriterien der Bestäuber evolviert sind. Die evolutionäre und ökologische Interaktion zwischen Pflanze und ihrem Bestäuber hängt in entscheidender Weise von dessen Fähigkeit ab Unterschiede bei den Pflanzenmerkmalen wahrzunehmen, und von den Mechanismen der Entscheidungsfindung. In der vorliegenden Arbeit steht die Ökologie kognitiver Funktionen im Vordergrund, um die Rolle der Informationsverarbeitung bei Bestäubern für die Evolution von Blütennektarmerkmalen zu untersuchen. In den ersten drei Kapiteln konzentriere ich mich auf die Fähigkeiten verschiedener Bestäuber zwischen Zuckerlösungen mit unterschiedlichen Konzentrationen zu diskriminieren. Im vierten Kapitel werden individuelle Unterschiede auch auf der Ebene des Nahrungssuchverhaltens genauer analysiert und mit der Effizienz des Nahrungssuchverhaltens in Zusammenhang gebracht. Das fünfte und letzte Kapitel baut auf den gewonnenen Erkenntnissen zur Psychometrie der Nektarqualitätswahrnehmung auf und befasst sich mit der evolutionären Entstehung von Nektareigenschaften. Diese Studien zeigen, wie die Untersuchung kognitiver Mechanismen von Bestäubern die evolutionäre und ökologische Forschung an zoophilen Pflanzen voranbringen kann. Zusätzlich wird somit Folgendes aufgewiesen: Der Methodenansatz der virtuellen Bestäubungsökologie kann aussagekräftige Erklärungen liefern für die evolutionäre Entstehung sowie Aufrechterhaltung von Pflanzenmerkmalen, die einer durch Kognition vermittelten und von Bestäubern ausgeübten Selektion unterliegen.<br>A diverse array of animals has specialized in consuming floral nectar – from butterflies and bees to hummingbirds and bats. The nectar characteristics of plant species often appear to reflect the needs of their dominant pollinator, for example plants pollinated by larger animals tend to produce larger amounts of nectar. This correspondence suggests that nectar traits have evolved in response to the choice behavior of pollinators. The evolutionary and ecological interaction between plants and their pollinators crucially depends on the pollinators’ ability to perceive differences in floral nectar traits and on their decision-making mechanisms. In the presented studies I adopt a cognitive ecology approach in order to investigate the role of information-processing in pollinators on the evolution of floral nectar traits. In the first three chapters I focus on the abilities of different pollinators to discriminate among sugar solutions with different concentrations. In Chapter 4 I present a detailed analysis of individual differences in the foraging context and discuss how they might relate to foraging efficiency. In the fifth and final chapter I use the findings on the psychophysics of nectar quality evaluation to address the question of the evolutionary origins of floral nectar traits. With these studies I show how the investigation of cognitive mechanisms of pollinators can inform evolutionary and ecological research on plants pollinated by animals. In addition, I demonstrate how the virtual pollination ecology methodology can explain the evolutionary origin and maintenance of plant traits that are subjected to cognition-mediated selection exerted by pollinators.
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Uvarovskii, Aleksei Verfasser], and Michael [Akademischer Betreuer] [Meyer-Hermann. "Mathematical modelling of lymphocyte-mediated immune responses / Aleksei Uvarovskii ; Betreuer: Michael Meyer-Hermann." Braunschweig : Technische Universität Braunschweig, 2017. http://d-nb.info/1175817570/34.
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Ali, Rehan. "Applications of Microscopy Image Analysis nd Modelling in Characterising the Mechanisms of Hypoxia-Mediated Resistance." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504283.
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Deckner, Emil, and Carl Mailer. "Participatory Modelling for Carbon Footprint Analysis : A Case Study at DeLava." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279522.
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Because of global warming, companies have started to tackle sustainability issues within their operations, but major uncertainties exist on how to establish a quantitative baseline of the current environmental performance of companies. Numerous investigations have been made to assess the carbon footprint of companies with a variety of methods, tools and strategies. However, the lack of transparency in the methods used and the assumptions made could prevent companies to replicate methods and to analyse the results. Because of this, we will investigate how participatory modelling could be used to create a model of the carbon emissions of a company, but also how this method enables the company to understand the methods used and the results from the investigation. By doing this, we also aim to clarify how the process could be set up, which stakeholders that need to be involved and what data sources that could be used. The thesis was conducted as a single case study at a manufacturing company named DeLaval. A participatory modelling process with three major phases was carried out according to proposed methodologies in previous research. In the first phase, a conceptual model of the system accounting for the emissions was created. In the second phase, a quantitative model of the system was developed by gathering data and validating the calculation methodologies with operational stakeholders within the company. In the third phase, the results were verified, and the company could set up sustainability targets based on the findings. The outcomes of the case study showed that there are major benefits with applying participatory modelling because different perspectives throughout the organisation could be gathered efficiently to create a representable model of the company. The modelling strategy had more benefits in organisational areas characterised by high complexity with numerous of different stakeholders with different roles or by geographical distribution. To create the model, primary data consisting of master product data and transactional data was used, together with secondary data, consisting of carbon emission coefficients and gap filling data created by the modellers. By basing the calculations on the methodology set up by the GHG protocol and anchoring the root definition of the system with strategic stakeholders, the results were trusted by the organisation.<br>På grund av den globala uppvärmningen har företag börjat att hantera hållbarhetsutmaningar inom sin verksamhet, men stora frågetecken kvarstår gällande hur en kvantifierad bild av företagets nuvarande utsläpp ska beräknas. Flertalet studier har genomförts för att undersöka koldioxidavtrycket på företag, med flertalet olika metoder och verktyg. Metoderna och antaganden som gjorts har dock bristande transparens, vilket hindrar andra företag från att replikera beräkningarna och att göra analyser av resultatet. Baserat på detta kommer denna studie att undersöka hur participativ modellering kan användas för att skapa en modell av koldioxidutsläppen från ett företag, men också hur denna metod underlättar för företaget att förstå metoderna som använts och resultaten från undersökningen. Genom detta ämnar vi att bringa klarhet gällande hur processen kan se ut, vilka intressenter som ska vara delaktiga och vilka datakällor som kan vara användbara. Studien genomfördes som en enkel fallstudie på det producerande företaget DeLaval. En participativ modelleringsprocess med tre faser genomfördes i enlighet med etablerade modelleringsprinciper från tidigare studier. I den första fasen utvecklades en konceptuell modell av systemet för estimering av koldioxidutsläppen. I den andra fasen utvecklades en kvantitativ modell as systemet genom att samla in data och validera beräkningsmetoderna tillsammans med operative intressenter på företaget. I den tredje fasen verifierades resultaten och företaget hade möjlighet att sätta upp hållbarhetsmål baserat på resultatet. Utfallet av fallstudien visar att det finns stora fördelar med att använda participativ modellering eftersom olika perspektiv i organisationen kunde inhämtas på ett effektivt sätt för att skapa en representativ modell av företaget. Modelleringsstrategin hade större fördelar i delar av företaget som karakteriserades av hög komplexitet, med många olika intressenter med olika roller eller av geografisk utspriddhet. För att skapa modellen krävdes primärdata innehållande produktinformation och transaktionsdata samt sekundärdata, innehållande utsläppsfaktorer och överbryggande data skapad av modellerarna. Genom att basera beräkningarna på metodiken skapad av GHG protocol och förankra syftet med systemet tillsammans med strategiska intressenter, skapades en tillit till resultaten inom organisationen.
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McGillen, Jessica Buono. "Mathematical modelling of metabolism and acidity in cancer." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:552f9ea8-ac6c-4413-9535-0318e855d85c.
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Human cancers exhibit the common phenotype of elevated glycolytic metabolism, which causes acidification of the tissue microenvironment and may facilitate tumour invasion. In this thesis, we use mathematical models to address a series of open problems underlying the glycolytic tumour phenotype and its attendant acidity. We first explore tissue-scale consequences of metabolically-derived acid. Incorporating more biological detail into a canonical model of acidity at the tumour-host interface, we extend the range of tumour behaviours captured by the modelling framework. We then carry out an asymptotic travelling wave analysis to express invasive tumour properties in terms of fundamental parameters, and find that interstitial gaps between an advancing tumour and retreating healthy tissue, characteristic of aggressive invasion and comprising a controversial feature of the original model, are less significant under our generalised formulation. Subsequently, we evaluate a potential role of lactate---historically assumed to be a passive byproduct of glycolytic metabolism---in a perfusion-dependent metabolic symbiosis that was recently proposed as a beneficial tumour behaviour. Upon developing a minimal model of dual glucose-lactate consumption in vivo and employing a multidimensional sensitivity analysis, we find that symbiosis may not be straightforwardly beneficial for our model tumour. Moreover, new in vitro experiments, carried out by an experimental collaborator, place U87 glioblastoma tumours in a weakly symbiotic parameter regime despite their clinical malignancy. These results suggest that intratumoural metabolic cooperation is unlikely to be an important role for lactate. Finally, we examine the complex pH regulation system that governs expulsion of metabolically derived acid loads across tumour cell membranes. This system differs from the healthy system by expression of only a few key proteins, yet its dynamics are non-intuitive in the crowded and poorly perfused in vivo environment. We systematically develop a model of tumour pH regulation, beginning with a single-cell scenario and progressing to a spheroid, within a Bayesian framework that incorporates information from in vitro data contributed by a second experimental collaborator. We predict that a net effect of pH regulation is a straightforward transmembrane pH gradient, but also that existing treatments are unable to disrupt the system strongly enough to cause tumour cell death. Taken together, our models help to elucidate previously unresolved features of glycolytic tumour metabolism, and illustrate the utility of a combined mathematical, statistical, and experimental approach for testing biological hypotheses. Opportunities for further investigation are discussed.
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Botfield, Andrew Civil & Environmental Engineering Faculty of Engineering UNSW. "Kinetic modelling studies of As(III) oxidation in dark pH 3 and 8 Fenton - mediated and pH 8 Cu(II) - H2O2 systems." Awarded by:University of New South Wales. School of Civil and Environmental Engineering, 2006. http://handle.unsw.edu.au/1959.4/31969.
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In this thesis, a combination of laboratory experimentation under well defined conditions coupled with a kinetic modelling approach is used to verify the existence and respective kinetic rates of previously unconfirmed or postulated mechanisms that drive and limit dark Fenton (Fe(II)/H2O2) - mediated As(III) oxidation at pH 3 and 8 and dark Cu(II) - H2O2 - mediated As(III) oxidation at pH 8. Dark Fenton - mediated oxidation of As(III) at pH 3 is first examined and the effects of the variation in the concentration of reactants (As(III), Fe(II) and H2O2), oxygen, phosphate and organics (2 - propanol, formate, and citrate) are reported and analysed. The kinetic models developed for these systems show high applicability to full scale water treatment application and key mechanistic findings include the significance of the cycling of Fe(II) / Fe(III) via HO2 ???/O2 ??????, the effects of As(IV) termination reactions in the absence of oxygen and the retarding effects of phosphate due to the postulated formation of a Fe(III) - phosphate complex (at a derived rate constant of 2.2 x 106 M-1s-1, that also appears to have negligible kinetic activity in terms of reduction to Fe(II) by HO2 ???/O2 ??????). The work also demonstrates the significance of the free radical by products of formate and citrate oxidation by ???OH (HCOO???/CO2 ?????? and 3HGA???2???). The examination of the dark Cu(II) - H2O2 - mediated oxidation of As(III) at pH 8 with variation in the concentration of reactants (As(III), Fe(II) and H2O2), carbonate and organics (2 - propanol, formate and citrate) demonstrated for the first time the high applicability of this system to the pre - oxidation of As(III) in water treatment and mechanistically that ???OH and CO3 ?????? are the dominant As(III) oxidants in this system. The As(III) oxidant CO3 ??????, is suggested to be generated by the interaction of ???OH and O2 ?????? with the carbonate matrix, at the respective rate constants of 4.9 x 107 M-1s-1 and 5.5 x 106 M-1s-1. Examination of the dark Fenton - mediated oxidation of As(III) at pH 8 and the effects of variation in the concentration of reactants (As(III), Fe(II) and H2O2), carbonate, organics (2 - propanol, formate and citrate) and Cu(II) demonstrates the varied potential mechanistic pathways in relation to the generation of As(III) oxidants from the Fenton reaction, Fe(II) + H2O2 such as Fe(IV) and CO3 ?????? and the previously dismissed ???OH, due to the presence of Fe(II) - citrate complexes. This work also demonstrates and models the enhancement of As(III) oxidation in the presence of an additional transitional metal ion, Cu(II).
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Woodford, Darragh J. "Riverscape-mediated effects of introduced trout on non-diadromous galaxiid fishes in New Zealand." Thesis, University of Canterbury. Biological Sciences, 2009. http://hdl.handle.net/10092/3284.
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The impact of invasive predators on native prey may depend on the availability and distribution of invader-free refugia across landscapes, if predators create demographic ‘sink’ populations in invaded patches, giving rise to source-sink dynamics in prey populations. Propagule pressure of immigrants dispersing from refugia (or sources) may consequently drive persistence in sink habitat, affecting predator-prey co-existence across the landscape. I studied whether introduced brown (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) create source-sink structuring in two native galaxiid fish species (Galaxias vulgaris and G. paucispondylus) in the rivers of the central South Island, New Zealand, and whether such dynamics affected the distributions of either species across river networks or “riverscapes”. Young-of-the-year (YOY) G. vulgaris recruitment was rare in trout-invaded streams and consistently high in trout-free streams. Thus, trout-free reaches appeared to act as sources in a river network, while the majority of the trout-invaded riverscape was a demographic sink (i.e., no local recruitment occurred). Surveys of YOY G. paucispondylus did not reveal trout-induced source-sink dynamics, although mesocosm predation experiments suggested both species were highly vulnerable to predation by large trout. Galaxias paucispondylus recruitment was highest in intermittently flowing streams that were marginal habitats for trout, suggesting indirect interactions between trout and habitat affect G. paucispondylus distribution. Network configuration of trout-free source populations affected the distribution of G. vulgaris, as galaxiids were excluded from small streams with high bed stability that were far from sources. The interaction between propagule pressure and habitat gradients in mediating effects of trout on G. vulgaris distributions indicates habitat characteristics affect predator-prey interactions in a spatially explicit manner. Furthermore, the outcome of predator-prey interactions should be able to be modelled using habitat data alone if habitat consistently mediates predator impacts. I developed a GIS-based spatial model to predict where trout would exclude G. vulgaris in river networks, based on stream size and distance to galaxiid source populations. The model was tested in three different riverscapes using fish occurrence patterns obtained from electrofishing surveys, and successfully predicted G. vulgaris exclusion by trout. This further demonstrates the importance of habitat configuration in driving interspecific interactions at the landscape scale. These findings suggest removing trout from small, stable tributaries to create new demographic sources could improve overall persistence of G. vulgaris across trout-invaded riverscapes. The galaxiid exclusion model should also be used to detect undiscovered trout-free source populations, and to aid in selecting streams for restoration of galaxiid populations through trout eradication.
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Sjögren, Erik. "Hepatic Disposition of Drugs and the Utility of Mechanistic Modelling and Simulation." Doctoral thesis, Uppsala universitet, Institutionen för farmaci, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-132571.
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The elimination of drugs from the body is in many cases performed by the liver. Much could be gained if an accurate prediction of this process could be made early in the development of new drugs. However, for the elimination to occur, the drug molecule needs first to get inside the liver cell. Disposition is the expression used to encapsulate both elimination and distribution. This thesis presents novel approaches and models based on simple in vitro systems for the investigation of processes involved in the hepatic drug disposition. An approach to the estimation of enzyme kinetics based on substrate depletion data from cell fractions was thoroughly evaluated through experiments and simulations. The results that it provided were confirmed to be accurate and robust. In addition, a new experimental setup suitable for a screening environment, i.e., for a reduced number of samples, was generated through optimal experimental design. The optimization suggested that sampling at late time points over a wide range of concentration was the most advantageous. A model, based on data from primary hepatocytes in suspension, for the investigation of cellular disposition of metabolized drugs was developed. Information on the relative importance of metabolism and membrane protein related distribution was obtained by analysis of changes in the kinetics by specific inhibition of the various processes. The model was evaluated by comparing the results to those obtained from an in vivo study analyzed with an especially constructed mechanistic PBPK model. These investigations showed that the suggested model produced good predictions of the relative importance of metabolism and carrier mediated membrane transport for hepatic disposition. In conclusion, new approaches for the investigation of processes involved in hepatic disposition were developed. These methods were shown to be robust and increased the output of information from already commonly implemented in vitro systems.
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Omoge, Akinyemi Paul. "The direct and mediated effects of customer relationship management (CRM) systems usage as service delivery channels on consumer buying behaviour : an empirical appraisal of the context of the Nigerian banking industry." Thesis, Robert Gordon University, 2016. http://hdl.handle.net/10059/2139.
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Ample evidence from the literature suggests that in recent years, banks have been heavily investing in customer relationship management (CRM) systems. The reasons for this are traced to banks' emergent need to gain and sustain competitive advantage through greater knowledge of their customers. In turn, this increased knowledge is likely to also lead to increased: a) customer base, b) customer satisfaction, c) customer retention and, d) customer loyalty. The literature suggests that there is a knowledge gap, which relates to the reasons for CRM systems in adoption and usage as service delivery channels, as well as its effects on banks' customers. This is particularly the case with regards to the banks' customers' buying behaviour and is stemming from the fact that bank customers display some unique buying patterns. Based on the above, the aim of this study is to find out whether or not there is a potential influence of newly implemented CRM systems on consumer buying behaviour in the context of the Nigerian banking industry and also to assess the extent and nature of this influence (if any).
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Janin, Grajcarek. "Genome-wide microhomologies enable precise template-free editing of biologically relevant deletion mutations." Kyoto University, 2020. http://hdl.handle.net/2433/253215.
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Staphorst, Leonard. "The impact of intellectual property rights from publicly financed research and development on governance mode decisions for research alliances." Diss., University of Pretoria, 2011. http://hdl.handle.net/2263/24604.
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This study consisted of two distinct research phases, performed within the context of the South African Council for Science and Industrial Research (and its current and potential research alliances). The purpose of the study was to develop a decision making model that would enable strategists at publicly financed research and development organisations to analyse and predict governance mode decisions, as well as select optimal governance mode structures (ranging from quasi-market structures, such as once-off contracts, to quasi-hierarchy structures, such as research joint ventures) for research alliances. During the qualitative first phase, the study aimed to identify impact domains within South Africa’s new Bayh-Dole-like Intellectual Property Rights legislative framework that consists of the Intellectual Property Rights from Publicly Financed Research and Development Act, as well as the Technology Innovation Agency Act, which could potentially influence research alliances (based on the Transactional Cost Economics, Resource-based View and Real Options Approach perspectives) with publicly financed research and development organisations. This was followed by the quantitative second phase, which attempted to verify the validity of a value-mediated governance mode model that included the highest ranked impact domains identified during the first phase as formative indicators for the perceived Intellectual Property Rights regime strength uncertainty factor. A qualitative online survey amongst senior managers at the Council for Science and Industrial Research, followed by Theme Extraction combined with Constant Comparative Method analysis, as well as a weighted frequency analysis, constituted the research methodology employed during the first phase’s identification and ranking of impact domains within the South African legislative framework. This phase demonstrated that the highest ranked impact domains (primarily driven by the Transactional Cost Economics perspective) included the choice of Intellectual Property Rights ownership, state walk-in rights on undeclared Intellectual Property, and benefit-sharing policies for the creators of Intellectual Property. The second phase consisted of a quantitative online survey, distributed amongst current and potential research alliance partners of the Council for Science and Industrial Research, followed by Structural Equation Modelling of a value-mediated governance model that included, amongst others, the perceived Intellectual Property Rights regime strength as an uncertainty factor. This phase revealed not only that the impact domains identified during the first phase could be used as formative indicators of the perceived Intellectual Property Rights regime strength, but also that stronger perceived regimes are positively related to the preference for quasi-hierarchy research alliance governance modes. Furthermore, it established that the expected value of a research alliance, which was shown to be positively influenced by the strength of the perceived Intellectual Property Rights regime, acted as a mediating factor on the relationship between the perceived Intellectual Property Rights regime strength and the preferred research alliance governance mode. Keywords: Bayh-Dole, Formative Indicators, Intellectual Property Rights, Research Alliances, Real Options Approach, Resource-based View, Quasi-Market Governance Modes, Quasi- Hierarchy Governance Modes, Structural Equation Modelling, Transactional Cost Economics, Value-mediated Governance Model. Copyright<br>Dissertation (MBA)--University of Pretoria, 2012.<br>Gordon Institute of Business Science (GIBS)<br>unrestricted
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Checcoli, Andrea. "Analisi di mobillità pedonale mediante dati di telefonia georeferenziati." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14600/.
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Al fine di organizzare al meglio le città del futuro occorrono nuovi strumenti in grado di analizzare e comprendere il comportamento delle persone nelle aree urbane. In questo elaborato viene illustrata la costruzione di un modello teorico relativo alla mobilità pedonale nella città di Venezia a partire dall'analisi di dati di telefonia mobile, rilevati nella giornata del 26 Febbraio 2017.
Vengono in seguito mostrate le differenti fasi necessarie alla realizzazione del modello a partire dall'elaborazione preliminare dei data set a disposizione e focalizzando poi l'attenzione sugli algoritmi di georeferenziazione disponibili in letteratura.
Una volta ultimata l'analisi dati, vengono esposti i concetti teorici che stanno alla base del modello realizzato ponendo l'accento sul carattere stocastico del fenomeno osservato si rivolge lo sguardo al risultato ottenuto portando alla luce le verifiche a cui viene sottoposto e le criticità che emergono nell'affrontare questo studio.
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Lister, Kendall. "Toward semantic interoperability for software systems." Connect to thesis, 2008. http://repository.unimelb.edu.au/10187/3594.
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“In an ill-structured domain you cannot, by definition, have a pre-compiled schema in your mind for every circumstance and context you may find ... you must be able to flexibly select and arrange knowledge sources to most efficaciously pursue the needs of a given situation.” [57]<br>In order to interact and collaborate effectively, agents, whether human or software, must be able to communicate through common understandings and compatible conceptualisations. Ontological differences that occur either from pre-existing assumptions or as side-effects of the process of specification are a fundamental obstacle that must be overcome before communication can occur. Similarly, the integration of information from heterogeneous sources is an unsolved problem. Efforts have been made to assist integration, through both methods and mechanisms, but automated integration remains an unachieved goal. Communication and information integration are problems of meaning and interaction, or semantic interoperability. This thesis contributes to the study of semantic interoperability by identifying, developing and evaluating three approaches to the integration of information. These approaches have in common that they are lightweight in nature, pragmatic in philosophy and general in application.<br>The first work presented is an effort to integrate a massive, formal ontology and knowledge-base with semi-structured, informal heterogeneous information sources via a heuristic-driven, adaptable information agent. The goal of the work was to demonstrate a process by which task-specific knowledge can be identified and incorporated into the massive knowledge-base in such a way that it can be generally re-used. The practical outcome of this effort was a framework that illustrates a feasible approach to providing the massive knowledge-base with an ontologically-sound mechanism for automatically generating task-specific information agents to dynamically retrieve information from semi-structured information sources without requiring machine-readable meta-data.<br>The second work presented is based on reviving a previously published and neglected algorithm for inferring semantic correspondences between fields of tables from heterogeneous information sources. An adapted form of the algorithm is presented and evaluated on relatively simple and consistent data collected from web services in order to verify the original results, and then on poorly-structured and messy data collected from web sites in order to explore the limits of the algorithm. The results are presented via standard measures and are accompanied by detailed discussions on the nature of the data encountered and an analysis of the strengths and weaknesses of the algorithm and the ways in which it complements other approaches that have been proposed.<br>Acknowledging the cost and difficulty of integrating semantically incompatible software systems and information sources, the third work presented is a proposal and a working prototype for a web site to facilitate the resolving of semantic incompatibilities between software systems prior to deployment, based on the commonly-accepted software engineering principle that the cost of correcting faults increases exponentially as projects progress from phase to phase, with post-deployment corrections being significantly more costly than those performed earlier in a project’s life. The barriers to collaboration in software development are identified and steps taken to overcome them. The system presented draws on the recent collaborative successes of social and collaborative on-line projects such as SourceForge, Del.icio.us, digg and Wikipedia and a variety of techniques for ontology reconciliation to provide an environment in which data definitions can be shared, browsed and compared, with recommendations automatically presented to encourage developers to adopt data definitions compatible with previously developed systems.<br>In addition to the experimental works presented, this thesis contributes reflections on the origins of semantic incompatibility with a particular focus on interaction between software systems, and between software systems and their users, as well as detailed analysis of the existing body of research into methods and techniques for overcoming these problems.
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Baratti, Emanuele <1983>. "Stima dei parametri di modelli idrologici mediante ottimizzazione dell’utilità." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6654/.
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Tradizionalmente, l'obiettivo della calibrazione di un modello afflussi-deflussi è sempre stato quello di ottenere un set di parametri (o una distribuzione di probabilità dei parametri) che massimizzasse l'adattamento dei dati simulati alla realtà osservata, trattando parzialmente le finalità applicative del modello.
Nel lavoro di tesi viene proposta una metodologia di calibrazione che trae spunto dell'evidenza che non sempre la corrispondenza tra dati osservati e simulati rappresenti il criterio più appropriato per calibrare un modello idrologico. Ai fini applicativi infatti, può risultare maggiormente utile una miglior rappresentazione di un determinato aspetto dell'idrogramma piuttosto che un altro.
Il metodo di calibrazione che viene proposto mira a valutare le prestazioni del modello stimandone l'utilità nell'applicazione prevista. Tramite l'utilizzo di opportune funzioni, ad ogni passo temporale viene valutata l'utilità della simulazione ottenuta. La calibrazione viene quindi eseguita attraverso la massimizzazione di una funzione obiettivo costituita dalla somma delle utilità stimate nei singoli passi temporali.
Le analisi mostrano come attraverso l'impiego di tali funzioni obiettivo sia possibile migliorare le prestazioni del modello laddove ritenute di maggior interesse per per le finalità applicative previste.<br>In the majority of rainfall-runoff modelling applications, the objective function to be minimised in the parameterisation procedure is
based on a measure of the goodness-of-fit that maximized the fit of the simulated data to the overall observed data, taking partially into account the specific model applications.
The present dissertation focuses on the development and testing of an objective function based on the expected utility of the rainfall-runoff model.
The method is based on the evidence that the performances of a hydrological model closely depend on the purpose of the application. For istance, the simulated data caught have different utility in a water resources management system or in a flood forecasting system.
In the proposed method, at each time step, the comparison between simulated and observed data is carried out by using an “ad-hoc” utility function. The calibration is performed by maximizing the overall estimated utility of the simulated data. Different utility functions are tested and the results are compared against those obtained with traditional procedure.
The results reveal that an adequate utility function allows an improvement of the model performances in the reproduction of the discharges considered most important to the purpose of the modeling application.
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Cedri, Sandro. "Analisi di strutture murarie rinforzate con FRP mediante modelli discretizzati." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amslaurea.unibo.it/164/.
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Bovo, Marco <1983>. "Valutazione della risposta sismica di edifici mediante modelli anelastici equivalenti." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5926/.
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Nella presente tesi è proposta una metodologia per lo studio e la valutazione del comportamento sismico di edifici a telaio. Il metodo prevede la realizzazione di analisi non-lineari su modelli equivalenti MDOF tipo stick, in accordo alla classificazione data nel report FEMA 440. Gli step per l’applicazione del metodo sono descritti nella tesi. Per la validazione della metodologia si sono utilizzati confronti con analisi time-history condotte su modelli tridimensionali dettagliati delle strutture studiate (detailed model). I parametri ingegneristici considerati nel confronto, nell’ottica di utilizzare il metodo proposto in un approccio del tipo Displacement-Based Design sono lo spostamento globale in sommità, gli spostamenti di interpiano, le forze di piano e la forza totale alla base. I risultati delle analisi condotte sui modelli stick equivalenti, mostrano una buona corrispondenza, ottima in certi casi, con quelli delle analisi condotte sui modelli tridimensionali dettagliati. Le time-history realizzate sugli stick model permettono però, un consistente risparmio in termini di onere computazionale e di tempo per il post-processing dei risultati ottenuti.<br>A new methodology for the study and evaluation of the seismic response of buildings is presented. The method involves the use of non-linear time-history analysis on equivalent MDOF stick models, according to the classification given in Report FEMA 440. The steps for implementing the method are described in the thesis. For the validation of the methods the results obtained were compared to that obtained by time-history analysis on detailed three-dimensional models of the structures studied (detailed model). The engineering parameters considered in the comparison, in order to use the proposed method in a Displacement-Based Design approach, are the top displacements, the inter-storey drifts, the forces at the floor and the base shear. The results of the conducted analyzes, on the equivalent stick models, match satisfactorily, in an excellent way in certain cases, those of the analyzes carried out on detailed model. The time-history on the stick model, however, allow a considerable saving in terms of computational effort and time for the post-processing of results.
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Morrone, Maria Francesca. "Analisi e confronto di sequenze di DNA mediante modelli Markoviani." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9508/.
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Lo scopo di questa tesi è quello di evidenziare, attraverso varie analisi statistiche ed applicazione di modelli stocastici, il comportamento strutturale e funzionale dei dinucleotidi che compongono le sequenze di DNA di diversi organismi. Gli organismi che abbiamo scelto di prendere in considerazione sono l'uomo, il topo e l'Escherichia coli. Questa scelta non è stata casuale, ma oculata, al fine di mettere in risalto alcune differenze tra organismi eucarioti, quali l'uomo e il topo, ed organismi procarioti come il batterio E.coli. Nella prima parte del nostro studio, abbiamo computato le distanze che intercorrono tra occorrenze successive dello stesso dinucleotide lungo la sequenza, usando un metodo di non sovrapposizione, ed abbiamo iterato il calcolo per tutti i 16 dinucleotidi. Dopodiché ci siamo preoccupati di graficare le distribuzioni di distanza dei 16 dinucleotidi per l'E.Coli, il topo e l'uomo; gli istogrammi evidenziano un comportamento anomalo della distribuzione di CG che accomuna gli organismi eucarioti e di cui, invece, è esente l'organismo procariote esaminato. Questo dato statistico trova una spiegazione nei processi biologici di metilazione che possono innescarsi sul dinucleotide CG nelle sequenze eucariotiche. In seguito, per determinare quanto ciascuna delle 16 distribuzioni si discosti dalle altre abbiamo usato la divergenza di Jensen-Shannon. Per quantificare le differenze sostanziali tra le distribuzioni di CG dei 3 organismi considerati abbiamo deciso di verificare quale fosse il miglior fit per tali curve tra un esponenziale ed una power-law. L'esponenziale rappresenta un buon fit per le code delle distribuzioni di CG del topo e dell'uomo; ciò rivela la presenza di una lunghezza caratteristica per entrambi gli organismi.
Nella seconda parte dello studio, i risultati vengono confrontati con modelli markoviani: sequenze random generate con catene di Markov di ordine zero (basate sulle frequenze relative dei nucleotidi) e uno (basate sulle probabilità di transizione tra diversi nucleotidi). Quest'ultima riproduce abbastanza fedelmente la sequenza biologica di partenza, per cui abbiamo scelto di utilizzare la catena Markov del 1° ordine per altre analisi statistiche riguardanti le distribuzioni dei nucleotidi, dinucleotidi, ed anche dei trinucleotidi con particolare interesse per quelli in cui è contenuto CG, in modo da verificare se l'anomalia si ripercuote anche in essi.
Riteniamo pertanto che metodi basati su questo approccio potrebbero essere sfruttati per confermare le peculiarità biologiche e per migliorare l'individuazione delle aree di interesse, come le isole CpG, ed eventualmente promotori e Lamina Associated Domains (LAD), nel genoma di diversi organismi.
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Metalli, Andrea. "Additive manufacturing: studio delle non conformità geometriche e dimensionali in componenti realizzati mediante tecnica fused deposition modelling." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10266/.
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La fabbricazione additiva è una classe di metodi di fabbricazione in cui il componente viene costruito aggiungendo strati di materiale l’uno sull’altro, sino alla completa realizzazione dello stesso. Si tratta di un principio di fabbricazione sostanzialmente differente da quelli tradizionali attualmente utilizzati, che si avvalgono di utensili per sottrarre materiale da un semilavorato, sino a conferire all’oggetto la forma desiderata, mentre i processi additivi non richiedono l’utilizzo di utensili. Il termine più comunemente utilizzato per la fabbricazione additiva è prototipazione rapida. Il termine “prototipazione”’ viene utilizzato in quanto i processi additivi sono stati utilizzati inizialmente solo per la produzione di prototipi, tuttavia con l’evoluzione delle tecnologie additive questi processi sono sempre più in grado di realizzare componenti di elevata complessità risultando competitivi anche per volumi di produzione medio-alti. Il termine “rapida” viene invece utilizzato in quanto i processi additivi vengono eseguiti molto più velocemente rispetto ai processi di produzione convenzionali.
La fabbricazione additiva offre diversi vantaggi dal punto di vista di:
• velocità: questi processi “rapidi” hanno brevi tempi di fabbricazione.
• realizzazione di parti complesse: con i processi additivi, la complessità del componente ha uno scarso effetto sui tempi di costruzione, contrariamente a quanto avviene nei processi tradizionali dove la realizzazione di parti complesse può richiedere anche settimane.
• materiali: la fabbricazione additiva è caratterizzata dalla vasta gamma di materiali che può utilizzare per la costruzione di pezzi. Inoltre, in alcuni processi si possono costruire pezzi le cui parti sono di materiali diversi.
• produzioni a basso volume: molti processi tradizionali non sono convenienti per le produzioni a basso volume a causa degli alti costi iniziali dovuti alla lavorazione con utensili e tempi di setup lunghi.
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Rivero, Martínez María José. "Diseño del proceso de purificación de estireno mediante adsorción en alúmina." Doctoral thesis, Universidad de Cantabria, 2002. http://hdl.handle.net/10803/10687.
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En este trabajo se ha realizado el diseño del proceso de purificación deestireno mediante adsorción en alúmina. Esta purificación consiste básicamente enla separación de agua y el inhibidor de la polimerización, 4-terc-butil catecol (TBC),presentes en el estireno como etapa previa en la obtención del caucho sintético, yaque la presencia de estos compuestos dificulta y encarece dicha operación.Para determinar las condiciones experimentales de trabajo, se ha tomadocomo referencia un proceso operativo actualmente a escala industrial en la plantade fabricación de caucho sintético que la empresa Dynasol Elastómeros posee enGajano (Cantabria). Así mismo, se ha empleado el estireno que esta empresautiliza como materia prima que posee alrededor de 150 mg/kg de agua y 15 mg/kgde TBC.En primer lugar, se ha procedido a la determinación de los equilibrios deadsorción agua-alúmina y TBC-alúmina. A continuación, se ha efectuado una seriede experimentos dinámicos a escala de laboratorio en los que se han obtenido laevolución de la concentración de cada uno de los adsorbatos en el estireno a lasalida de la columna de adsorción en función del tiempo. Posteriormente, se hallevado a cabo el desarrollo del modelo matemático para lo que se han analizadolas distintas etapas en el proceso de transferencia de materia, así como susconsecuentes resistencias, y se han obtenido los parámetros correspondientes.A continuación, se ha realizado un análisis del cambio de escala, para lo quese ha procedido a la construcción de una planta piloto en la propia factoría queproduce el caucho sintético, en la que se han realizado diversos experimentos quehan sido contrastados con las simulaciones que predecía el modelo matemático. Lacomparación ha permitido validar el modelo y los parámetros cinéticos.Finalmente, utilizando el modelo y los parámetros obtenidos en las etapasanteriores se ha simulado el proceso de purificación de estireno operativo a escalaindustrial.<br>In this work, the design of the purification process of styrene by adsorptiononto activated alumina, has been carried out. The purification consists basically ofremoving water and a polimerisation inhibitor, 4-terc-butyl catechol (TBC), as aprevious step in the manufacture of synthetic rubber.To determine the experimental working conditions, a real process thatoperates on industrial scale in a factory which produces synthetic rubber in Spain(Dynasol Elastómeros) has been taken as reference. The styrene used in this workis the industrial raw material and contains approximately 150 mg/kg of water and 15mg/kg of polimerisation inhibitor.First, adsorption equilibrium water-alumina and TBC-alumina have beenstudied. Then, some dynamic experiments on laboratory scale have been carriedout in order to obtain breakthrough curves for both adsorbates. A mathematicalmodel that describes the mass transfer process has been developed analysing thepossible resistances, and the corresponding parameters have been obtained.To analise the scale-up of the adsorption process a pilot plant has been builtin the synthetic rubber factory and the experimental results have been comparedwith the results predicted by the mathematical model. Finally, thanks to themathematical model, the parameters that have been obtained during the laboratoryscale experiments and its validation on pilot plant scale, a model that can describethe industrial process and can be useful to find the best operation conditions hasbeen developed.
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Muscolino, Elena. "Studio parametrico del comportamento di opere di sostegno flessibili mediante modellazione numerica." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amslaurea.unibo.it/2068/.
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Oggetto di questa tesi è lo studio parametrico del comportamento di paratie mediante modellazione numerica agli elementi finiti.
Si è anche analizzato l’aspetto normativo relativo ad esse ed in particolare si è applicato il D.M. 2008 ad una paratia sottolineando le innovazioni nella progettazione geotecnica.
Le paratie sono opere di sostegno flessibili interagenti con i fronti di scavo e costituite da una porzione fuori terra, soggetta a condizioni di spinta attiva, e una porzione interrata che contrappone la resistenza passiva del terreno.
Le opere di sostegno flessibile si dividono in due categorie: diaframmi e palancole che differiscono molto fra loro sia per il materiale con cui sono realizzate, sia per la tecnica di messa in opera, sia per la geometria, ma hanno in comune il meccanismo di funzionamento.
Sono stati illustrati i metodi di calcolo per lo studio delle paratie: metodi dell’equilibrio limite a rottura, metodi a molle e metodi agli elementi finiti.
I metodi agli elementi finiti negli ultimi anni hanno avuto maggior successo grazie alla possibilità di definire il modello costitutivo sforzi-deformazioni, le condizioni al contorno e le condizioni iniziali.
Esistono numerosi programmi di calcolo che si basano sul metodo agli elementi finiti, tra i quali è da annoverare il programma Plaxis che viene molto usato grazie alla presenza di vari modelli costitutivi in grado di simulare il comportamento del terreno. Tra i legami costitutivi presenti nel programma Plaxis, sono stati presi in esame il modello Mohr-Coulomb, l’Hardening model e il Soft Soil Creep model e sono poi stati applicati per eseguire uno studio parametrico del comportamento delle paratie. Si è voluto comprendere la sensibilità dei modelli al variare dei parametri inseriti nel programma. In particolare si è posta attenzione alla modellazione dei terreni in base ai diversi modelli costitutivi studiando il loro effetto sui risultati ottenuti. Si è inoltre eseguito un confronto tra il programma Plaxis e il programma Paratie. Quest’ultimo è un programma di calcolo che prevede la modellazione del terreno con molle elasto-plastiche incrudenti.
Il lavoro di tesi viene illustrato in questo volume come segue: nel capitolo 1 si analizzano le principali caratteristiche e tipologie di paratie mettendo in evidenza la complessità dell’analisi di queste opere e i principali metodi di calcolo usati nella progettazione, nel capitolo 2 si è illustrato lo studio delle paratie secondo le prescrizioni del D.M. 2008. Per comprendere l’argomento è stato necessario illustrare i principi base di questo decreto e le caratteristiche generali del capitolo 6 dedicato alla progettazione geotecnica.
Le paratie sono poi state studiate in condizioni sismiche secondo quanto previsto dal D.M. 2008 partendo dall’analisi degli aspetti innovativi nella progettazione sismica per poi illustrare i metodi pseudo-statici utilizzati nello studio delle paratie soggette ad azione sismica.
Nel capitolo 3 si sono presi in esame i due programmi di calcolo maggiormente utilizzati per la modellazione delle paratie: Paratie e Plaxis. Dopo aver illustrato i due programmi per comprenderne le potenzialità, i limiti e le differenze, si sono analizzati i principali modelli costituitivi implementati nel programma Plaxis, infine si sono mostrati alcuni studi di modellazione presenti in letteratura. Si è posta molta attenzione ai modelli costitutivi, in particolare a quelli di Mohr-Coulomb, Hardening Soil model e Soft Soil Creep model capaci di rappresentare il comportamento dei diversi tipi di terreno.
Nel capitolo 4, con il programma Plaxis si è eseguita un’analisi parametrica di due modelli di paratie al fine di comprendere come i parametri del terreno, della paratia e dei modelli costitutivi condizionino i risultati. Anche in questo caso si è posta molta attenzione alla modellazione del terreno, aspetto che in questa tesi ha assunto notevole importanza. Dato che nella progettazione delle paratie è spesso utilizzato il programma Paratie (Ceas) si è provveduto ad eseguire un confronto tra i risultati ottenuti con questo programma con quelli ricavati con il programma Plaxis.
E’ stata inoltra eseguita la verifica della paratia secondo le prescrizioni del D.M. 2008 dal momento che tale decreto è cogente.
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Longo, Rosario Alessandro. "Dalla generazione di modelli 3D densi mediante TLS e fotogrammetria alla modellazione BIM." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13284/.
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La tesi tratta la ricerca di procedure che permettano di rilevare oggetti utilizzando il maggior numero di informazioni geometriche ottenibili da una nuvola di punti densa generata da un rilievo fotogrammetrico o da TLS realizzando un modello 3D importabile in ambiente FEM.
Il primo test si è eseguito su una piccola struttura, 1.2x0.5x0.2m, in modo da definire delle procedure di analisi ripetibili; la prima consente di passare dalla nuvola di punti “Cloud” all’oggetto solido “Solid” al modello agli elementi finiti “Fem” e per questo motivo è stata chiamata “metodo CSF”, mentre la seconda, che prevede di realizzare il modello della struttura con un software BIM è stata chiamata semplicemente “metodo BIM”. Una volta dimostrata la fattibilità della procedura la si è validata adottando come oggetto di studio un monumento storico di grandi dimensioni, l’Arco di Augusto di Rimini, confrontando i risultati ottenuti con quelli di altre tesi sulla medesima struttura, in particolare si è fatto riferimento a modelli FEM 2D e a modelli ottenuti da una nuvola di punti con i metodi CAD e con un software scientifico sviluppato al DICAM Cloud2FEM.
Sull’arco sono state eseguite due tipi di analisi, una lineare sotto peso proprio e una modale ottenendo risultati compatibili tra i vari metodi sia dal punto di vista degli spostamenti, 0.1-0.2mm, che delle frequenze naturali ma si osserva che le frequenze naturali del modello BIM sono più simili a quelle dei modelli generati da cloud rispetto al modello CAD. Il quarto modo di vibrare invece presenta differenze maggiori.
Il confronto con le frequenze naturali del modello FEM ha restituito differenze percentuali maggiori dovute alla natura 2D del modello e all’assenza della muratura limitrofa.
Si sono confrontate le tensioni normali dei modelli CSF e BIM con quelle ottenute dal modello FEM ottenendo differenze inferiori a 1.28 kg/cm2 per le tensioni normali verticali e sull’ordine 10-2 kg/cm2 per quelle orizzontali.
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Banari, Maria. "La generazione di modelli tridimensionali densi in ambito architettonico mediante la fotogrammetria digitale." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10857/.
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The Italian territory offers a wide range of treasures in the field of Cultural Assets.
This is a highly relevant property, which needs an accurate management and preservation performed by appropriate tools, also giving attention to the maintenance and safeguard from risk factors.
Nowadays the increasing development of new digital technologies, added by remarkable steps forward got by the subject of Geomatic makes possible an efficient integration among different techniques, helped also by spread of solutions to improve the data import-export and transmission between different devices.
The main objective of this thesis is to experience the photogrammetric restitution implemented in a commercial software of digital photogrammetry, in order to generate a dense 3D model of the facade of the Basilica Sant'Apollinare Nuovo in Ravenna.
The 1st Chapter, after a general introduction regarding the 3D survey of Cultural Heritage and some considerations linked to the use of digital photogrammetry in this field, is focused to analyze the case of stereoscopic and the monoscopic approach. In particular, it develops the theme of close-range photogrammetry.
The 2nd Chapter, exposes the theme of digital images, from color theory until their appearing on the monitor.
The 3rd Chapter, develops the case study of the Basilica di Sant'Apollinare Nuovo, the historical, architectural and religious of the same. Also, it is examined the issue of photogrammetry and laser scanning of the case study. The final part of the same chapter, treats the processing of data processing the software Agisoft PhotoScan, in order to generate, by means of Structure from Motion technique, a digital geometric 3D model of the Basilica Facade. The digital model has been scaled on the basis of measurements made on the field. With the software it was possible to accomplish the three phases of the photogrammetric data processing: internal orientation, exterior orientation and restitution.
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Vignoli, Giovanni. "Previsioni in tempo reale di precipitazioni spazialmente distribuite mediante sensori remoti e modelli dinamici." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20171/.
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Tesi volta a studiare i modelli facenti parte di Rainymotion per previsioni meteo a breve termine (Nowcasting). La prima parte della Tesi riguarda un approfondimento sulle previsioni meteo, la loro affidabilità e gli strumenti utilizzati. In seguito vi è una trattazione più approfondita degli strumenti radar, delle loro applicazioni, dell'equazioni utilizzate per ricavare l'intensità di pioggia dalle misure degli echi radar e dai possibili errori che ne possono derivare. Infine è stato fatto un confronto tra le diverse tipologie di modello (Dense, DenseRotation, Sparse, SparseSD) in occasione di sei eventi intensi del 2019 in Emilia-Romagna: una nevicata di gennaio, un evento di pioggia intenso in aprile, un evento di pioggia e grandine a maggio, un tipico temporale estivo breve ed intenso di giugno, un evento intenso di ottobre e un insieme di eventi di pioggia di novembre che hanno investito la regione per una settimana. Sulla base dei risultati ottenuti, confrontati con i valori di intensità misurati realmente, è stata fatta una valutazioni sulla qualità e accuratezza del modello nel prevedere fenomeni di precipitazione.
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Turba, Maria Elena <1978>. "Studio, mediante applicazioni biotecnologiche, di tre diversi modelli spontanei o indotti di patologie del sistema nervoso." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/31/.
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Castelli, Claudia. "Valutazione dell’efficacia di barriere chimiche contro l’umidita’ da risalita capillare nelle murature mediante modelli di laboratorio." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016.
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La risalita capillare di umidità nelle murature storiche è la principale responsabile del degrado dei materiali. La metodologia ad oggi più utilizzata in tale campo è quella basata sull’iniezione di prodotti chimici in grado di formare barriere artificiali che blocchino il flusso ascendente dell’acqua, ma è ancora in fase di perfezionamento. Per potere svolgere tale perfezionamento, è utile disporre di una metodologia attendibile per la valutazione dell’esito dei trattamenti, ossia un metodo standardizzato che possa garantire una corretta misurazione del contenuto di umidità nelle murature pre e post iniezioni.
Nella presente tesi, che ha lo scopo di valutare l’efficacia di alcuni prodotti per barriere chimiche nelle murature, si è utilizzato un metodo di laboratorio standardizzato proposto dai ricercatori del LASTM (DICAM), che permette di riprodurre in laboratorio il processo di risalita dell’umidità e, allo stesso tempo, permette di potere svolgere le misurazioni del contenuto d’acqua interno ai materiali con il metodo diretto.
I trattamenti, svolti in collaborazione con la Azienda inglese “Safeguard”, produttrice di resine impermeabilizzanti, sono stati effettuati su vari modelli, costituiti di laterizi e malta, preventivamente sottoposti a differenti condizioni ambientali. Successivamente si è svolto un monitoraggio periodico per potere determinare sia l’efficacia dell’intervento che l’attendibilità del modello. Dopo avere studiato un sistema di controllo delle condizioni di laboratorio, si è ritenuto opportuno svolgere anche alcune prove di caratterizzazione dei materiali utilizzati nella costruzione dei vari modelli, per conoscerne appieno le caratteristiche e potere valutare con maggiore attendibilità i risultati dei trattamenti.
Infine, per approfondire le dinamiche di diffusione dei formulati chimici all’interno dei materiali, si sono svolte prove su travetti di malta.
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Romanelli, Aurora. "Metodi e Modelli di supporto alla gestione dei costi manutentivi di flotte auto aziendali mediante analisi predittive." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
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Ogni giorno all'interno di tutte le aziende ci si trova a dover prendere decisioni di diverso tipo, nelle quali la Data Science può essere un valido strumento di supporto.
Il progetto riportato in tesi, infatti, nasce dalla necessità di risolvere una problematica dell'azienda Global Sistemi, la quale si trova ad aver bisogno di un prodotto che possa fornirle informazioni utili nel processo decisionale.
Global Sistemi offre ai propri clienti un software per la gestione di flotte di auto ed ha recentemente deciso di ampliare le funzionalità del prodotto offrendo loro la possibilità di ottimizzare l'utilizzo delle proprie risorse, ponendo particolare attenzione sulle spese annuali sostenute per ogni auto della flotta.
Per lo sviluppo di tale progetto è stata necessaria l'acquisizione di quanti più dati l'azienda possedesse sulle auto in questione. Le informazioni ottenute sono state studiate per poter essere filtrate mantenendone solo la parte rilevante, la quale è stata successivamente analizzata dal punto di vista qualitativo e manipolata al fine di produrre un dataset da sottoporre ad algoritmi predittivi alla base della Data Science.
Attraverso diverse tecniche di Data Science, come Regressione e Classificazione, e l'utilizzo di reti neurali si è potuto addestrare un modello, il quale al termine del processo di addestramento è in grado di predire con una discreta accuratezza se una determinata auto nell'anno successivo comporterà costi manutentivi maggiori di 550 euro. Questo prodotto permetterà ai possessori di parchi auto di avere un supporto nelle decisioni relative alla propria flotta come ad esempio la rottamazione o l'acquisto di un'auto.
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Chiodi, Filippo. "Modellazione e simulazione di un sistema di trasporto cooperativo mediante l'utilizzo di velivoli pilotati da remoto." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/22910/.
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In questa trattazione viene elaborato un modello di sistema di trasporto collaborativo che, mediante l’utilizzo di due quadrirotori APR, ci permette di trasportare in volo un corpo rigido rappresentato da un’asta collegata ai due quadrirotori mediante dei cavi. Questo modello viene, poi, implementato su Matlab tramite la sua estensione Simulink e sono presentati i risultati di alcune simulazioni effettuate.
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Colin, Fabio. "Dispersione di sostanze odorigene nell'atmosfera e modellizzazione mediante software dedicato (un'applicazione del software LAPMOD)." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/9761/.
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Gli odori rappresentano uno degli elementi di disturbo che la popolazione avverte maggiormente e, anche nel caso in cui non siano associati a sostanze tossiche, sono causa di conflitti e di intolleranza, sia nei confronti delle aziende che li diffondono nel territorio, sia nella scelta del sito di localizzazione di nuovi impianti.
La valutazione del disturbo olfattivo e la sua regolamentazione (esistono linee guida, ma non una legislazione di riferimento) rappresentano aspetti caratterizzati da elevata complessità, dal momento che l’inquinamento olfattivo è strettamente associato alla percezione umana.
Nella tesi vengono valutate le emissioni odorigene e le relative immissioni, dovute ad un comparto per la gestione integrata dei rifiuti. Per caratterizzare le emissioni sono stati prelevati dei campioni di aria presso le principali sorgenti individuate e quantificate utilizzando la tecnica dell’olfattometria dinamica. Una volta caratterizzate le sorgenti, i dati di emissione ottenuti dalla campagna di misura e dall’analisi olfattometrica sono stati utilizzati come dati di input del modello LAPMOD (LAgrangian Particle MODel). LAPMOD è stato implementato con un modulo specifico per la determinazione delle concentrazioni massime orarie che utilizza un peak-to-mean variabile nel tempo, a differenza di altri modelli che usano un valore costante per la determinazione. Dall'elaborazione dei dati è emerso che, utilizzando il modulo specifico per gli odori, le concentrazioni come 98° percentile riferite al giorno tipico hanno un andamento opposto rispetto all’uso di un peak-to-mean costante.
Dal confronto della simulazione in cui le emissioni sono indipendenti dalla variazione della portata di odore in funzione della velocità del vento, con quella che invece simula tale dipendenza (nelle sorgenti che presentano paratie laterali e tettoia) è emerso che la simulazione che mitiga completamente l’effetto del vento è più coerente con la realtà.
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Parmeggiani, Stefano. "Analisi degli effetti di ripascimenti o dragaggi sulla spiaggia sommersa mediante modellazione numerica 2DH." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amslaurea.unibo.it/133/.
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Ollas, Johanna, and Sara Soltaniah. "Bilateral teleoperation : A study of architectures under different network delays." Thesis, KTH, Mekatronik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-287351.
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A bilateral teleoperation system makes it possible for a human operator to interact with a remote environment and receive feedback from their actions. In this work, two different teleoperation architectures are studied, one well-established approach called position-force, and another approach called Model-Mediated Teleoperation (MMT). Position-force generates force feedback by measuring forces and sending them over the network, subject to network delay, while MMT generates nondelayed force feedback through a local environment model. The two architectures are compared in terms of transparency (quality of force feedback) and state consistency (equivalence of positions) under different network conditions. Up to 150 ms constant delay in Round Trip Time (RTT) is added. Both architectures are implemented as relatively simple versions of themselves. The case (teleoperation task) under consideration is pushing a cuboid object on a planar surface in a single direction. The MMT architecture is also studied in further detail, in terms of model complexity. Two versions of an MMT model are investigated, one simpler model that has a linear representation of energy loss and one less simple model that has a non-linear representation of energy loss. The purpose is to see what implications there are of increasing or decreasing model complexity. The results indicate that position-force has better performance in terms of both transparency and state consistency than both MMT models for all investigated network conditions. The simple version of MMT (linear model) performs better than the non-linear model, in terms of transparency and state consistency of cuboid positions, for all network conditions except the largest added delay. In terms of state consistency for the device positions, the non-linear model only performs better than the linear model with no added delay.<br>En distansstyrt system med tvåsidig kommunikation gör det möjligt för en mänsklig operatör att interragera med en avlägsen miljö och få återkoppling. I detta arbete studeras två olika arkitekturer för dessa typer av system. Ett väletablerat tillvägagångssätt som kallas position-force, och ett annat som kallas Model-Mediated Teleoperation (MMT). Position-force genererar kraftåterkoppling genom att mäta krafter och skicka dem över nätverket, utsatt för nätverksfördröjningar, medan MMT genererar en icke-fördröjd kraftåterkoppling från en lokalt modellerad miljö. De två arkitekturerna jämförs med avseende på ”transparency” (kvalitén på kraftåterkopplingen) och ”state consistency” (matchning av positioner) under olika nätverksförhållanden. De studerade förhållandena innefattar upp till 150 ms konstant fördröjning i tur och returtid. Båda arkitekturer implementeras som förhållandevis enkla versioner av sig själva. Det studerade fallet (operatörens uppgift) innefattar puttande på ett rätblock på en plan yta i en enkel riktning. MMT arkitekturen studeras även i vidare detalj med avseende på komplexitet hos den lokala modellen. Två versioner av MMT modellen undersöks, en enklare model som har en linjär representation av energiförlust, och en mer avancerad model som har en icke-linjär representation av energiförlust. Avsikten bakom detta är undersöka vilka implikationer som finns när komplexiteten hos modellen höjs eller sänks. Resultaten indikerar att position-force presterar bättre än MMT med avseende på både transparency och state consistency för alla undersökta nätverksfördröjningar. Den linjära MMT modellen presterar bättre än den icke-linjära modellen, med avseende på transparency och state consistency i rätblockspositioner, för alla nätverksförhållnaden utom den största pålagda fördröjningen. Vidare presterar den icke-linjära modellen bättre än den linjära modellen, med avseende på state consistency för styrande/styrd apparat, endast då ingen nätverksfördröjning läggs på.
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Tarantino, Maria Nastasia. "Valutazione degli effetti delle emissioni in atmosfera di uno stabilimento agroindustriale mediante software CALPUFF." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
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Oggetto del lavoro di tesi è la trattazione e la modellazione delle emissioni in aria di inquinanti tipici degli stabilimenti industriali, mediante software CalPuff.
È stato applicato il modello CALPUFF a uno stabilimento industriale per valutarne gli effetti in termini di concentrazioni degli inquinanti che colpiscono l'uomo.
Si è stimata la variazione degli effetti delle emissioni fra stato attuale e configurazione futura, nella previsione del raddoppio della capacità produttiva dell’impianto.
Il software comprende tre processori: un preprocessore, CALMET per l’elaborazione dei dati metereologici, il processore centrale, CALPUFF, per la determinazione del file delle concentrazioni calcolate nella griglia di calcolo, e un post-processore CALPOST, che rende leggibili e fruibili i risultati da parte di software esterni per la relativa visualizzazione grafica. La simulazione è stata svolta tenendo conto dei dati dell’intero anno solare 2013.
I risultati sono stati elaborati attraverso il software SURFER in grado di fornire isoplete di concentrazione che, riportate sulla mappa del territorio, consentono una chiara visualizzazione delle concentrazioni di inquinanti al suolo.
Dai dati ottenuti si rileva che il contributo degli emissivi inquinanti dell’impianto sia modesto e si esclude che possa arrivare a “colpire” l’area urbana, esterna al dominio di calcolo e posta a sud ovest rispetto allo stabilimento.
Si ridurrà in maniera sensibile l’impatto ambientale in termini di concentrazioni di inquinanti al suolo nella configurazione futura e dunque il contributo nocivo dell’impianto alla qualità globale dell’aria.
Il miglioramento ottenibile nello scenario futuro è ascrivibile da un lato alla scelta progettuale di aumentare l’altezza dei camini per favorire la dispersione di inquinanti in atmosfera e diminuirne la ricaduta al suolo, dall’altro, all’adozione di ulteriori sistemi di abbattimento di inquinanti nei fumi in uscita rispetto alla configurazione attuale.
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Fiorentino, Domenico. "Interazione visuo-acustica e fenomeni di plasticità sinaptica: studio mediante un modello di rete neurale applicato al ventriloquismo." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/4863/.
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Cortecchia, Silea. "Evoluzione temporale del fabbisogno e del deficit irriguo delle principali colture in Italia: analisi mediante dati satellitari e modelli idrologici." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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In un contesto di scarsità di risorsa idrica e forti cambiamenti climatici è fondamentale conoscere l’effettiva disponibilità idrica per le colture. Il presente elaborato di tesi si propone di analizzare l’evoluzione temporale del fabbisogno irriguo e del deficit irriguo per le colture cerealicole mais, orzo e grano duro, nelle regioni Lombardia, Emilia Romagna e Sicilia, per due orizzonti temporali (2000-2017 e 2030-2050). Relativamente al periodo 2000-2017, i risultati aggregati a scala annuale mostrano un fabbisogno irriguo in Lombardia ed Emilia Romagna con valori tra 500-550 mm/anno per l’orzo e tra 740-850 mm/anno per mais e grano duro. La Sicilia presenta invece valori significativamente maggiori e pari a 745 mm/anno per l’orzo, e circa 1000-1200 mm/anno per mais e grano duro. In termini di deficit irriguo, stante una diminuzione di precipitazione da nord verso sud, con valori di 924 mm/anno, 750 mm/anno e 578 mm/anno rispettivamente per Lombardia, Emilia Romagna e Sicilia, la regione che presenta le condizioni più critiche indipendentemente dal tipo di coltura è la Sicilia. E' stato poi condotto uno studio più approfondito per la regione Emilia Romagna nell’anno 2017, in cui è stato applicato il modello d’infiltrazione SCS, per stimare il quantitativo d’acqua effettivamente infiltrato nel sottosuolo. Considerando invece il periodo 2030-2050, a partire da simulazioni climatiche, i dati mostrano un debole aumento dell’evapotraspirazione a scala nazionale, mentre le precipitazioni presentano un incremento significativo in Lombardia ed Emilia Romagna e una sostanziale diminuzione in Sicilia. Tale situazione verosimilmente porterà ad un aumento del deficit irriguo in Sicilia, mentre Lombardia ed Emilia Romagna vedranno una leggera diminuzione.
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Angotti, Giancarlo. "Fenomeni di interazione audio-visiva in soggetti sani e in soggetti autistici: analisi mediante rete neurale." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7935/.
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Negli ultimi anni, studi scientifici hanno evidenziato come il nostro sistema nervoso abbia la capacità di combinare e integrare informazioni di diversa natura sensoriale. Una interazione ampiamente studiata è quella audiovisiva. Oggetto principale di questa tesi è un esempio di interazione audiovisiva, ovvero un fenomeno illusorio visivo indotto dal suono che prende il nome “sound-induced flash illusion”: quando una coppia flash+beep è preceduta o seguita - ad una distanza temporale detta Stimulus Onset Asynchorny (SOA) - da un secondo beep, i soggetti spesso riportano la percezione di aver visto due flash. Il fenomeno illusorio tende a svanire al crescere dell’SOA, e si definisce “finestra temporale d’integrazione” l’intervallo di valori di SOA all’interno del quale si verifica l’illusione. Il fenomeno illusorio è presente anche nei soggetti autistici; questi, rispetto ai soggetti sani, presentano una maggiore propensione nel riportare l’illusione e una finestra temporale d’integrazione di durata maggiore. Obiettivo di questo lavoro è stato approfondire questi fenomeni di interazione mediante l’utilizzo di un modello di rete neurale precedentemente sviluppato dal gruppo di Bioingegneria dell’Università di Bologna. Tale modello era in grado di simulare il fenomeno illusorio, ma presentava il limite di non considerare l’intera finestra temporale in cui tale fenomeno si verifica. Un’analisi di sensitività del modello ha individuato quali variazioni dei parametri potessero spiegare l’illusione in un ampio intervallo temporale e interpretare le differenze tra soggetti sani e soggetti autistici. I risultati delle simulazioni hanno evidenziato un soddisfacente accordo con i dati di letteratura. Le analisi svolte possono contribuire a chiarire i meccanismi alla base del fenomeno illusorio e della finestra temporale in cui esso ha luogo e a fare luce sulle possibili alterazioni nelle singole aree cerebrali e nella interazione tra esse che possono interpretare le differenze osservate nei soggetti autistici rispetto ai sani.
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Tomassoni, Federica <1972>. "Valutazione quantitativa dei recettori della somatostatina in tumori neuroendocrini e loro valutazione funzionale mediante nuovi analoghi della somatostatina in modelli cellulari." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/482/.
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Russo, Ennio. "Stima della dispersione degli stadi planctonici (uova e larve) dell'alice europea, Engraulis encrasicolus, mediante l'utilizzo di modelli matematici. Possibili relazioni con il reclutamento." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/4878/.
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Luis, Alconero Patricia. "Intensificación del proceso de absorción de dióxido de azufre mediante contacto no dispersivo y líquidos iónicos." Doctoral thesis, Universidad de Cantabria, 2009. http://hdl.handle.net/10803/10693.
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La intensificación de procesos consiste en el desarrollo de equipos y técnicas innovadoras que ofrecen mejoras sustanciales en el proceso, principalmente mediante la disminución del volumen del equipo, consumo de energía o generación de residuos, dando lugar a tecnologías más baratas, seguras y sostenibles. Esta tesis enfatiza la intensificación de procesos como estrategia en la recuperación de dióxido de azufre mediante el empleo de la tecnología de membranas y de líquidos iónicos como absorbente con objeto de eliminar las pérdidas de disolvente.La intensificación del proceso se lleva a cabo en dos etapas:i) Sustitución del equipo convencional (e.g. scrubbers) por un sistema de membranas para eliminar el arrastre de gotas y,ii) Sustitución del disolvente de absorción (N,N-dimetilanilina) por líquidos iónicos para eliminar pérdidas de disolvente por su volatilización en la corriente de gas debido a su presión de vapor despreciable. La selección de un líquido iónico adecuado se basa en su afinidad hacia dióxido de azufre, baja viscosidad, bajo coste y baja ecotoxicidad.En resumen, esta tesis es el primer trabajo que combina el empleo de un contactor de membranas de fibra hueca con líquidos iónicos, contribuyendo al desarrollo de procedimientos innovadores para intensificar el proceso de absorción de dióxido de azufre.<br>Process intensification consists of the development of innovative devices and techniques that offer significant improvements in chemical manufacturing and processing, decreasing substantially equipment volume, energy consumption, or wastes, and ultimately leading to cheaper, safer and sustainable technologies. This thesis emphasizes the process intensification as the strategy to the recovery of sulfur dioxide, according to the material efficiency and environmental protection, by means of technology based on membranes and ionic liquids as absorption solvents in order to avoid solvent losses.Process intensification is performed in two steps:i) Substitution of conventional equipment (e.g. scrubbers) for a membrane device to avoid drops dragging and,ii) Substitution of the absorption solvent (N,N-dimethylaniline) for ionic liquids to avoid solvent losses due to volatilization of solvent into the gas stream because of their negligible vapor pressure. Selection of a suitable ionic liquid is based on its affinity towards sulfur dioxide, low viscosity, low cost and low ecotoxicity.Thus, this thesis is the first work that combines a hollow fibre membrane contactor and ionic liquids, contributing to the development of innovative procedures to intensify the sulfur dioxide absorption process.
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Duesterberg, Christopher Ku Civil & Environmental Engineering Faculty of Engineering UNSW. "Kinetic modelling of Fenton-mediated oxidation: reaction mechanism, applications,and optimization." 2007. http://handle.unsw.edu.au/1959.4/40651.
Full textAbstract:
The ever-increasing detection of harmful organic and inorganic compounds in habitable areas throughout the world has led to mounting research into applications and techniques for the treatment of contaminated soils, surface and groundwaters, and chemical and industrial wastewaters. Chemical oxidation technologies, in particular Fenton-based remediation systems, have exhibited considerable potential for the effective treatment and remediation of such contaminated waters and soils. The use of Fenton-based oxidation systems for the treatment of contaminated waters and wastewaters warrants the development of kinetic models capable of accurately simulating system behaviour. In this thesis, the kinetics of Fenton-mediated oxidation systems and kinetic models based on its governing reaction mechanism are investigated in order to highlight those parameters and conditions that effect Fenton chemistry and oxidation performance, and to demonstrate the application of such kinetic models to design and improve treatment systems. Experimental and simulated data describing the oxidation of formic acid by Fenton's reagent at low pH (3 to 4) and under a variety of initial conditions, operating regimes, and solution environments supports a proposed reaction mechanism that nominates the hydroxyl radical (OH) as the active oxidizing intermediate in Fenton-based oxidation systems. Laboratory experiments demonstrate that formic acid oxidation is inhibited in the presence of oxygen, and model simulations of these systems reveals that such behaviour is due to the effect organic radical intermediates and/or by-products have in assisting or hindering the redox cycling of the catalytic iron species. The critical role that iron redox cycling plays in affecting oxidation performance is further highlighted by experimental and simulated studies at alternate pHs and using different target organics, including those that react directly with iron in a redox capacity. Experiments at pH 4 reveal an increase in the redox cycling of iron and improved oxidation performance compared to pH 3 as the higher pH favours the superoxide radical, a stronger reductant than the hydroperoxyl radical that predominates at pH 3. Other laboratory and modelling studies on the Fenton-mediated oxidation of certain aromatic compounds highlight the manner in which quinone and quinone-like compounds, being added directly or generated as oxidation by-products, can improve oxidation performance via redox reactions with iron. Further simulations reveal the type of practical design and operating information kinetic models can provide for treatment processes, though it is noted an appropriate understanding of the oxidation mechanism of the target species is necessary for the accurate application of the model.
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Sarika, C. K. "Thin Film Instabilities Mediated Self-Assembly of Polymer Grafted Nanoparticles." Thesis, 2015. http://etd.iisc.ernet.in/2005/3836.
Full textAbstract:
After the advent of nanotechnology, self-assembly has become an active area of research, as it being one of the few efficient methods to generate ensembles of nanostructures. In this thesis, we present studies on two dimensional self-assembly of polymer grafted nanoparticle (PGNPs) and thin film modelling approach to understand the physics involved in the self-assembly mechanism of polymeric nanoparticles. The two dimensional, hierarchical assemblies of PGNPs are created from evaporating solution films spread at the air-water interface using Langmuir-Blodgett technique. A transition in the patterns is observed with increase in concentration which is followed by a remarkable re-entrance of initial patterns with further concentration increment. The pattern is long length scale network type at low and high concentrations whereas it is short length scale distribution of clusters at intermediate concentrations. Clusters are composed of lateral arrangement of individual PGNPs. The characteristics of clusters are tailored by changing various experimental conditions such as molecular weight of the grafted chains, concentration, temperature and evaporation rate. The patterns are unaffected by the transfer surface pressure, suggesting that the self-assembly occurs in the presence of solvent via solution thin film instabilities and the resulting structures of PGNPs are frozen upon complete evaporation. Films of neat polystyrene also exhibit similar morphology and transitions in pattern length scales with initial solution concentration as observed in PGNP films. This confirms that the self-assembly of PGNPs is driven by the intrinsic nature of the grafted polymer chains.
Gradient dynamics model is employed to study the stability and dynamics of polymer solution thin films by incorporating Flory Huggins free energy and concentration dependent Hamaker constant. Dispersion curves obtained from linear stability analysis of thin film equations show existence of bimodal instability in the film that corresponds to dewetting and decomposition. Phase diagram spanned by concentration and Flory parameter indicate that the thin film instability transits from dewetting to decomposition and then re-enters to dewetting with increase in concentration of the solution. Using the material parameters of the PGNP thin films for linear stability analysis, experimental observations of bimodal length scale of patterns and re-entrant nature are well explained. Nonlinear simulations which are performed to capture the evolution of patterns in the film show that the decomposition progresses through different pathways depending upon the concentration of the solution. This is explained
by analyzing the local variation of spinodal parameter (curvature of the free energy per unit area) in the film.
The gradient dynamics model is extended to study the stability and dynamics of evaporating solution thin films. Nonlinear simulations demonstrate that the film undergoes evaporative thinning without any significant growth of dewetting or decomposition instability initially and becomes unstable at a certain intermediate thickness where the spinodal parameter of dewetting or decomposition changes the sign. The rupture of the film (dewetting) or the phase segregation (decomposition) occurs explosively and subsequently evaporation progresses till the film attains chemical equilibrium with the ambient vapour phase. Rate of evaporation significantly affect the intermediate thickness at which the patterns emerge and thereby determines the length scale of initial patterns and instability growth rate. Quasi-steady analysis and nonlinear simulations show that the length scales of patterns of dewetting and decomposition decrease with evaporation rate and exhibit a power law behaviour. Thin films in which the solvent quality drops down with confinement due to evaporation are modelled by assuming a simple functional dependence of Flory parameter on mean film thickness. Quasi-steady analysis demonstrates that the dominating instability of such films switches from dewetting to decomposition and then returns to dewetting with increase in the initial concentration of the solution. We note that even though the functional form of Flory parameter with confinement is not exact, it represents the essential nature of the expected variation. We presume that the phenomenon discussed above is quite generic and may manifest itself in many situations where thin films of colloidal solutions undergo a decrease in the solvent quality due to confinement effects resulting in a competition between spinodal dewetting and decomposition instabilities.
This will result in a competition and interplay of the different instability scales and by choosing appropriate control parameters novel self-assembled patterns can be created.