Integrated design approach for responsive solar-shadings in double skin facades in hot arid climate

Ph. D. Thesis.To deliver climate adaptive architecture, current trends in architecture are directed towards dynamic and responsive building skins. ‘Responsive building skin’ is used to describe the ability of building envelopes to adapt in real time in response to external environmental conditions. Recent attention has focused on ‘soft robotics’ approach which uses soft and/or extensible materials to deform with muscle‐like actuation, mimicking biological systems. Material embedded actuation can autonomously alter shading systems’ morphology stimulated by external environmental conditions. Passively thermally‐activated shading systems offer responsive actuation by solar‐radiation and stratified hot air in a double skin façade (DSF) without recourse to energy consuming systems. This research identifies the intersection between bio‐inspiration, folding principles and smart materials to integrate the underlying mechanisms in responsive solar‐shading systems and assesses their environmental performance. The thesis proposes an interdisciplinary mixed methodology linking hands‐on experimentation with environmental performance simulation of responsive building skins. ‘Practice‐led approach’ is used to explore the design potential of responsive systems using smart materials. ‘Computational Fluid Dynamics’ (CFD) numerical methods are used to measure the impact of responsive solar‐shading systems on multiple environmental factors in a DSF cavity. This helps the design decisions, selection and customisation of smart materials. Hands‐on experimentation is used to explore various prototypes, leading to the selection of a folded prototype, to be simulated for environmental performance. Solar‐shading systems are tested within a DSF, in an hot arid climate. Flat and folded solar‐shading devices are installed in a DSF cavity with three aperture sizes (30%, 50% & 70%) to represent the responsive system states. Point‐in‐time simulations are carried at 9:00 am, 12:00 pm and 15:00 pm in peak summer and winter day. The developed analytical design framework presents different design parameters for responsive solar‐shading systems to guide decision‐making in research of climate actuated smart shading systems. Keywords: Responsive skins, Adaptive facades, Soft robotics, Bio‐inspiration, Origami, Deployable structures, Actuation, Smart materials, Shape memory alloys, Double skin facades, Energy efficiency, Digital simulation, CFD Modelling

Cholestasis-Induced Cognitive Decline: Neurological Mechanisms and Therapeutic Implications

Ph. D. ThesisCognitive dysfunction occurs during the cholestatic liver disease Primary biliary Cholangitis (PBC). Patients experience with short-term memory and concentration deficit, termed ‘brain fog’. This can be debilitating and severely affect quality of life, with no beneficial treatments (Newton, Hollingsworth et al. 2008) In this thesis, using the murine Bile Duct Ligation (BDL) model and in vitro modelling with human neuronal cells, I investigated the effects of cholestasis on the blood-brain barrier (BBB) and resultant changes within the brain. This study focussed on the hippocampus due to its crucial role in learning and memory. Changes to BBB could be observed from day 6, including astrocyte detachment, and permeability using MRI. By day 10 mice had visual spatial memory deficits, neuroinflammation was seen within the hippocampus, and changes were observed in gamma frequency oscillations. Interestingly, neurons in the hippocampus possessed features of senescence in cholestatic mice (telomere associated DNA damage, and P21+ RNA), highlighting parallels in pathology between the liver (where senescence is known to occur during cholestasis) and the brain. This effect was mirrored during in vitro studies, where neurons treated with PBC patient serum (to simulate pathological exposure to bile acids) also displayed increased sen-B-gal, a feature of senescence. In another strand, I examined the ability of both approved (ursodeoxycholic acid, Obeticholic Acid) and experimental (Bezafibrate) therapies to modify cognitive processes. Only Obeticholic Acid provides a potential therapeutic due to its in vivo and in vitro effects. Strikingly, OCA improve cognition and reduces neuronal senescence in BDL mice and in vitro when neurons are pre-treated before serum treatments. Therefore, the data presented in this thesis implicates senescence as a key pathological feature of cholestatic disease not just in the liver but also in brain where it has been previously linked to poor cognition (Baker, Wijshake et al. 2011, Fielder, Tweedy et al. 2020). Further investigation of early intervention with OCA may prove beneficial to patients experiencing cognitive deficit

Intrusion detection system for IoT networks for detection of DDoS attacks

PhD ThesisIn this thesis, a novel Intrusion Detection System (IDS) based on the hybridization of the Deep Learning (DL) technique and the Multi-objective Optimization method for the detection of Distributed Denial of Service (DDoS) attacks in Internet of Things (IoT) networks is proposed. IoT networks consist of different devices with unique hardware and software configurations communicating over different communication protocols, which produce huge multidimensional data that make IoT networks susceptible to cyber-attacks. The network IDS is a vital tool for protecting networks against threats and malicious attacks. Existing systems face significant challenges due to the continuous emergence of new and more sophisticated cyber threats that are not recognized by them, and therefore advanced IDS is required. This thesis focusses especially on the DDoS attack that is one of the cyber-attacks that has affected many IoT networks in recent times and had resulted in substantial devastating losses. A thorough literature review is conducted on DDoS attacks in the context of IoT networks, IDSs available especially for the IoT networks and the scope and applicability of DL methodology for the detection of cyber-attacks. This thesis includes three main contributions for 1) developing a feature selection algorithm for an IoT network fulfilling six important objectives, 2) designing four DL models for the detection of DDoS attacks and 3) proposing a novel IDS for IoT networks. In the proposed work, for developing advanced IDS, a Jumping Gene adapted NSGA-II multi-objective optimization algorithm for reducing the dimensionality of massive IoT data and Deep Learning model consisting of a Convolutional Neural Network (CNN) combined with Long Short-Term Memory (LSTM) for classification are employed. The experimentation is conducted using a High-Performance Computer (HPC) on the latest CISIDS2017 datasets for DDoS attacks and achieved an accuracy of 99.03 % with a 5-fold reduction in training time. The proposed method is compared with machine learning (ML) algorithms and other state-of-the-art methods, which confirms that the proposed method outperforms other approaches.Government of Indi

Music of the French Counterculture: 1966-1975

Ph. D. Thesis.The French counterculture of the 1960s and 1970s developed in connection to a network of countercultures across the globe. This thesis studies the role that these relationships had in the development of French countercultural music and musical discourses. To conduct this research, this study principally relies on analysis of three central thencontemporary music magazines: Actuel, Rock & Folk, and Best. The analysis of these magazines is complimented by musical and semiotic analyses. In this way this text balances a consideration of written cultural discourse and insight drawn from investigation of aesthetic choices. This study offers new insight into processes of musical and countercultural development in France. These years saw a complicated and shifting discourse where French youth sought to work out how to both identify with a transnational youth movement and retain a sense of national individuality. Music is placed at the centre of this tension as it acted as a vehicle to engage with national Others and as a way of articulating a sense of the national Self. This study views the development of the French counterculture as a result of national and transnational processes. Chapters 2 and 4 view the reception and response to international actors by looking at France’s relationship with the counterculture of the USA and the UK respectively. Chapter 3 turns the attention to circulations within French borders by considering the interplay between the French folk revival and the French counterculture. Chapter 5 features the most direct study, out of the chapters within this thesis, on the internal dialogue about the development of French rock music taking place within countercultural circles

Early Modern Utopian Writings and the Just Commonwealth

PhD ThesisThis thesis sets out to examine the interplay between utopian theory and political practice through close readings of three key texts in the early modern Western utopian tradition, Thomas More’s foundational Utopia (1516), Francis Bacon’s New Atlantis (1626) and Jonathan Swift’s Gulliver’s Travels (1726). It argues that early modern utopian literature offers two competing approaches to the imagining of an ideal society: the practical-oriented approach initiated by Bacon, and the moderate, sceptical approach inspired by Plato’s Republic and Ciceronian civil philosophy, which is here represented by More and Swift. Modern utopias are widely understood as blueprints for social reform by scholars such as Karl Popper (1945), Krishan Kumar (1987) and Ruth Levitas (2009). This thesis argues, instead that this modern concept of utopia emerges when utopias adopt the Baconian approach and break away from the classical heritage. More broadly, this thesis aims to recover the value of the rich intellectual tradition of early modern utopian thinking; this includes its sceptical engagement with the project of utopianism. We can only understand our own desire for civic reform with a fuller understanding of this tradition. In Chapter One, I argue that More’s Utopia is a cautionary tale against the passion for the ideal society. The description of utopia is preceded by a dialogue on whether philosophers should adapt to political reality or uphold their idea of justice without compromise. The dialogical form, with its openness, encourages critical assessment of the zealous character Hythlodeaus who longs for Utopia, and his position is further undermined when his monologue on the best commonwealth becomes fraught with difficulties and contradictions. Chapter Two argues that Bacon turns utopian literature into an applicable blueprint for political reform and his New Atlantis thus marks a turning point for utopian literature. Concerned about the religious conflict in his day, Bacon advocates a religiously tolerant and charitable utopia. For the first time, utopia is conceived as a solution to a specific problem instead of the best commonwealth. In Chapter Three, I argue that Gulliver’s Travels criticizes the Baconian approach for abandoning the topic of the best commonwealth while simultaneously reappraising the Platonic ideal. Despite his apparent endorsement of the classical tradition, Swift is in fact deeply sceptical of whether the return to a Platonic approach is feasible when the understanding of man and society has been radically reshaped by modern science

Optogenetic investigation of cortical network dynamics in epilepsy

Ph. D. ThesisUnderstanding the cortical network properties which determine the susceptibility of cortex to the onset of seizures remains a major goal of epilepsy research. The determinants of seizure risk in cortical networks are dynamic, showing dependency on intrinsic cortical activity and environmental influences. The failure to identify reliable electrographic indicators of imminent seizure onset suggests that the contributory factors may not be electrographically obvious. A strong candidate for such a property is the activity dependent disinhibition of the excitatory network which results from increases in intracellular chloride concentration. Chloride loading has been shown previously to occur during periods of intense neuronal activity, resulting from concomitant excitatory and inhibitory synaptic transmission. To explore how network dynamics evolve from a stable healthy state to one permissive for the onset and propagation of seizures, I used an optogenetic approach to selectively interrogate dynamic changes to excitatory transmission between the principal cells of the cortical circuit following an acute ictogenic challenge, both in vitro and in vivo. Using ultra-low frequency optogenetic stimulation genetically targeted to the pyramidal cells of neocortex, I demonstrate that epileptiform activity, which develops spontaneously following an acute chemoconvulsant challenge, can both be reduced and monitored, using an active probing strategy. Delivering continuous and focal optogenetic stimulations to superficial neocortex and regions of the hippocampal formation evokes glutamatergic responses in the LFP which can be used to assay dendritic excitability in the network. At ultralow frequencies, between 0.1-0.033 Hz, optogenetic stimulation markedly reduced the rate of evolution of epileptiform activity, when delivered to neocortex or hippocampal structures, in acutely prepared adult mouse brain slices bathed in 0Mg2+ perfusate. The response evoked by these test pulses undergoes an all-or-nothing transformation observable in the LFP which reliably telegraphed the onset of ictal activity in two models of epilepsy. Using electrophysiological tools and 2-photon calcium imaging of individual dendrites, I demonstrate that this phenomenon likely reflects a reduction in the threshold for dendritic spikes. Using an anatomically realistic computational model pyramidal cell I show that this effect is reproduced by modest positive shifts in the GABAergic reversal potential in distal pyramidal cell dendrites. Finally, I report preliminary data demonstrating a potential mechanism for the diurnal modulation of seizure risk. Diurnal periodicity in seizure susceptibility have been observed longitudinal recordings from both patients and chronically epileptic experimental animals. Using the optical chloride sensor ClopHensor I examine steady-state pyramidal cell chloride concentration over the diurnal period and show that periodicity in chloride homeostasis is consistent with the phase of diurnally modulated seizure risk. In this thesis I use a range of optical and electrophysiological tools to explore the contribution of dynamic chloride concentration in pyramidal cells in determining cortical susceptibility to seizures onset. Using two acute epilepsy models I demonstrate that an assayable increase in dendritic excitability precedes ictogenesis, and demonstrate a potential mechanism by which variation in [Cl-]i can give rise to this effect. I go on to show diurnal variation in [Cl-]i in cortical pyramidal cells, and link this to circadian modulation of susceptibility to chemoconvulsants, suggesting a functional mechanism for the dynamic seizure risk observed in epileptic patients

Cryopreservation of retinal organoids and applications of RPE cells for disease modelling in retinitis pigmentosa

PhD ThesisGeneration of retinal cells from human induced pluripotent stem cells (hiPSCs) provides great opportunities for research and therapeutics. In this study, we generated hiPSC-derived retinal cells to evaluate their ability to be cryopreserved, shipped at room temperature (RT), and assess their application in disease modelling by studying the mechanisms causing Retinitis Pigmentosa (RP). To develop an effective cryopreservation protocol for the long-term storage of retinal organoids (ROs), previously published cryopreservation methods were used. The structure and presence of retinal cells in cryopreserved ROs were assessed by immunofluorescence analysis. The ‘Master Liver Supercooling’ protocol was the most promising among all in preserving the overall retinal structure. However, success was limited, and only PRs survived. To assess whether hiPSC-derived ROs can be shipped at RT, ROs were kept at RT for 5 days or shipped internationally for 3 days using a commercial container. The structure, morphology and function of ROs were assessed by immunofluorescence, transmission electron microscopy and electrophysiology, indicating no differences between control, RT incubated and shipped organoids. This study provides an effective shipping method to facilitate the transportation of ROs at RT. To identify the disease mechanisms of RP associated with PRPF31 mutations (known as RP11), proteomic analyses of hiPSCs-retinal pigmented epithelium (RPE) cells from control and RP11- patients were conducted. These showed that RNA splicing, retinoid metabolism and visual perception, and protein folding pathways were affected. RP11-RPE cells were characterised by reduced functional PRPF31 protein and the presence of insoluble aggregates containing mutant PRPF31, misfolded and ubiquitin-conjugated proteins. The waste disposal mechanisms were impaired exacerbating aggregate formation which was associated with cell death activation. Treatment of RP11-RPE cells with rapamycin (autophagy activator) reduced cytoplasmic aggregates and improved cell survival. This thesis highlights the applications of hiPSC-derived retinal cells and provides more insights in cryopreservation, transportation and potential therapeutics for RP

Cosmological implications of field space geometry

PhD ThesisOne of the most fascinating aspects of recent endeavours in theoretical cosmology has been the investigation of the quantum e ects of scalar elds in eld-spaces with non-trivial geometries, in the early universe. The objective of this thesis is the presentation of a series of original research topics that result from such considerations. The rst part of this work explores an extension to Starobinsky's model of stochastic in ation. The functional integral describing the stochastic dynamics of a spectator eld during in ation is reviewed. Comparisons are drawn between the diagrammatic expansion resulting from action and the one obtained directly from a perturbative solution of the corresponding Langevin equation. The Feynman rules for computing arbitrary temporal n-point functions are stated and illustrative computations are presented. The role played by the functional Jacobian determinant in the path integral is given increased attention. Multiplicative noise is also brie y considered; allowing the eld to contribute to the expansion rate introduces additional vertices and exciting insights on the dependence of observable results on the discretization prescription are motivated. The second part presents a covariant under eld rede nitions E ective Field Theory proposed towards the resolution of the existing tension of conformal frame dependence. We are motivated by the meta-stability of the Higgs vacuum which, in the early universe, can lead to complications. It is shown, here, that the e ective Higgs potential at large eld values can be derived in a way that is independent of the choice of conformal frame for the spacetime metric, resulting in unambiguous answers to questions about physical observables (eg.vacuum stability). This approach leads to new relations for the evolution of the coupling coe cients with the energy scale and motivates improved limits on the allowed values of the Higgs-curvature coupling. The third part investigates the dynamics of a multi eld in ation model with curved eld-space. Abandoning the assumption of a single in aton, which is both unphysical and not motivated by higher energy theories, results in the introduction of a scalar multiplet, with non-trivial kinetic terms. The recently proposed and topical Hyperin ation model is reviewed and a concise treatment of the evolution of the background and the quantum perturbations is introduced. Thus, bounds for the cosmological observables are established and comparisons with experimental data are drawn, resulting in restrictions in the admissible values of the eld-space curvature paramete

Visibility and acceptance of discrete-sampling artifacts in visual displays

Ph. D. Thesis.Digital visual displays are aimed to provide an illusion of a continuous reality through a discrete presentation of visual information. This thesis explored three topics on (i) angular, (ii) spatial, and (iii) temporal sampling characteristics, related to distortion visibility, acceptance, and discomfort. In the first topic, we addressed the issue of optimizing the view density in continuous parallax visualization by replicating the changing views of a 3-D object for a moving observer. We measured the visibility of the related artifacts and evaluated the performance of full-reference visual quality metrics. We found that the state-of-the-art metrics can indirectly characterize artifact visibility and established a quantitative relationship for threshold estimation on varying conditions. The second topic addressed the relation of the contrast sensitivity function (CSF) to adaptation luminance and specifically its asymptotic behavior at high light levels essential to modern high-luminance displays. Using a custombuilt system, we measured the CSF at relatively high luminance levels and spatial frequency range, integrating our dataset to the existing research. We found a gradual transition among the linear to DeVries-Rose to Weber regions with steeper slopes for higher frequencies and lower luminance. A further decreasing region was located at low to intermediate frequencies. Following this construct, we adopted a model consisting of central elements in the visual signal processing and proposed an eight-parameter form for the CSF in the luminance domain. The final topic addressed the effects of frame rate on distortion acceptance and its impact on visual discomfort during regular display use. We assessed the perceived symptoms, preference, and task performance under varying conditions. The measurements indicated that for nondemanding everyday tasks, the frame rate could be reasonably reduced without severe effects on the observer; however, this tolerance diminished under more dynamic content. A potential association of discomfort with the blinking activity was also discussed.European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 676401, European Training Network on Full Parallax Imaging and Huawei Technologies Co., Lt

Modelling of Fine Chemical Manufacturing Effluent and Emissions: Implementation of Mathematical and Physical Models for Wastewater Management

Eng. D. Thesis.This thesis consists of a portfolio of four projects that investigates, and addresses challenges faced by fine chemical and pharmaceutical manufacturers based in the UK to achieve greater control of effluent and air emissions in an environment of tightening legislation. In part one of this research, a mathematical model based on modified continually stirred tank reactor (CSTR) in series equations was created using MATLAB and deployed as a standalone tool with graphical user interface (GUI) to allow non-experts to predict the concentration of substances through a complex plant effluent system and activated sludge wastewater treatment plant (WWTP). The model showed an average prediction accuracy to within 9% of the true value on-site when validated against a tracer compound. In Part two of the thesis, a 100 litre small-scale activated sludge wastewater treatment plant was designed and built to enable extended testing of treatment efficiency for potential new wastewater streams for a large-scale (2400 m3 reactor) plant, to reduce the risk of breaching site effluent consent limits or large scale microorganism poisoning. Plant variables and conditions required to maintain equivalent wastewater treatment performance from the large-scale to the small-scale plant were researched and found to include temperature, pH, dissolved oxygen (DO) concentration, hydraulic retention time (HRT) and solids retention time (SRT). The resulting pilot plant matched performance of the large-scale plant to within 12.8% of effluent chemical oxygen demand (COD) concentration. Long term treatment efficiency testing of a methylene-blue dye containing wastewater was conducted and shown to be satisfactory after a period of microorganism acclimation, where equivalent short-term lab respirometry testing had previously shown no digestion of the blue wastewater. In part three of this thesis, mathematical models were researched and developed in MATLAB to study prediction of the effluent chemical oxygen demand concentration of an activated sludge wastewater treatment plant. Existing methods of non-linear modelling using partial least squares (PLS) and artificial neural network (ANN) structures were investigated and compared against a newly proposed structure that replaces the linear inner regressor of the PLS algorithm with a combination of multiple neural networks (mNNPLS). The mNNPLS model showed an improved correlation coefficient (R2) of 0.855 between observed variables and predicted effluent chemical oxygen demand. In the final section of the thesis, a methodology was created for conducting consequence and risk modelling using DNV’s PHAST software to compliment the studies in parts one and two by allowing estimation of substance input concentrations to the effluent system from potential major accidents to aid emergency response planning and test the robustness of the effluent system. Sources for input data including individual and societal risk criteria are researched and presented along with techniques of scenario identification, results presentation and overall report format