Online social networks (OSNs) have seen a remarkable rise in the presence of automated social agents, or social bots. Social bots are the new computing viral, that are surreptitious and clever. What facilitates the creation of social agents is the massive human user-base and business-supportive operating model of social networks. These automated agents are injected by agencies, brands, individuals, and corporations to serve their work and purpose; utilising them for news and emergency communication, marketing, social activism, political campaigning, and even spam and spreading malicious content. Their influence was recently substantiated by coordinated social hacking and computational political propaganda. The thesis of my dissertation argues that automated agents exercise a profound impact on OSNs that transforms into an array of influence on our society and systems. However, latent or veiled, these agents can be successfully detected through measurement, feature extraction and finely tuned supervised learning models. The various types of automated agents can be further unravelled through unsupervised machine learning and natural language processing, to formally inform the populace of their existence and impact.

"Instead of studying, for example, how the psychology of personality limits and prevents real social and political change, we should be studying how political and ideological changes create new personalities and individual needs and motives." The above quotation is from social psychologist Professor John Turner, who is one of the two theorists, the other being Henri Tajfel, most responsible for the Social Identity Perspective, the principle subject of this thesis. The Social Identity Perspective is an approach to Social Psychology that incorporates two sub-theories: Tajfel's Social Identity Theory and Turner's Self-Categorization Theory. This thesis is based upon using the perspective for the purposes of creating more realistic and believable fictional characters in realist fiction. For the purposes of this thesis Pam Morris' definition of realism will be used, that being, 'any writing that is based upon an implicit or explicit assumption that it is possible to communicate about a reality beyond the writing.' According to both theories, individuals can develop two principal identities: the personal self, which is to say a collection of idiosyncratic qualities that define them as a unique individual, and a collective self (or social identity) that encapsulates the status and characteristics of the social groups they belong to in opposition to other social groupings. Turner theorised that the personality of a human being is heavily influenced by their social context at an unconscious level. This influence can be made manifest by their parents, by their school friends and work colleagues, by their romantic partners, and especially by the collective cultural expectations native to the area they choose to reside in. Turner put forward the concept that our personality and actions are therefore influenced by society at the level of how the individual defines himself or herself. This occurs without agency on the part of the individual. These social belief systems therefore mould what the individual thinks, their actions, and their motivations. This thesis will demonstrate a method of usage for elements of Social Psychology, specifically the Social Identity Perspective that underpins the actions, interactions and motivations of the fictional characters contained within the thesis's creative element. It is the contention of this thesis that The Social Identity Perspective will assist an author in marrying together ever more realistic characterisation to other areas of writer research already extensively drawn upon by the author such as those projects focused upon creating a more realistic setting in a historical novel for instance. As previously stated it is the intention of this thesis to apply aspects of social psychology to the creation of realist texts only, the findings however may also be of use to authors who write in other genres, after all even the writer of fantastic fiction still requires characters whose actions are fundamentally recognisable and justifiable to the reader in order for them to be able to make sense of the fiction and as Henry James said, 'one can speak best from one's own taste, and I may therefore venture to say the air of reality (solidity of specification) seems to me to be the supreme virtue of a novel'. It is the aim of this thesis that its findings may highlight the potential of using The Social Identity Perspective and other adjuncts of Social Psychology as tools for both plot construction and character development that is completely realistic. This may then lead to other areas of research, some of which are suggested in the concluding chapter of this thesis.

Les microsphères polymériques, biodégradables et biocompatibles sont prometteuses comme échafaudages pour fournir des cellules aux tissus sans dommage et améliorer la réponse des cellules souches. Il a été montré que les microparticules à base de PLGA à base de protéines ECM préparées par une technique d'extraction par solvant en émulsion améliorent l'adhésion et la prolifération des cellules souches. Bien qu'un certain effet biologique du revêtement protéique sur les microparticules de polymère soit établi, il n'est pas bien compris car des informations détaillées sur l'interaction entre les propriétés de surface des particules chimiques et physiques, l'adsorption protéique et la réponse cellulaire restent floues. Le but de cette étude est d'établir une relation entre les propriétés de surface des particules qui proviennent des variables utilisées lors des formulations, l'adsorption des protéines et la réponse des cellules souches pour permettre une conception plus rationnelle des microparticules. Deux types de polymères différents (PLGA et PLGA-P188-PLGA) et deux stabilisants d'émulsion différents; un polymérique PVA et une huile polaire Propylène glycol ont été utilisés pour préparer quatre types de particules dans un procédé en émulsion. Les particules ont été caractérisées en termes de taille, charge, topographie et morphologie et chimie de surface Identification des effets des variables dans la chimie et l'émulsifiant des polymères Des surfaces de polymère plat recouvertes de spins sont générées pour comprendre les interactions entre les polymères et les molécules d'adhésion de la fibronectine et de la poly-D-Lysine pour la fonctionnalisation des microparticule. / Polymeric, biodegradable and biocompatible microspheres are promising as colloidal scaffolds to deliver cells to tissues without damage and to enhance stem cell survival. It has been shown that PLGA (poly(lactic-co-glycolic acid)) based microparticles prepared by an emulsion solvent extraction technique and functionalised with ECM proteins improves stemcell adhesion and proliferation. While it is established that the presence of proteins in these systems has abiological effect, the interplay between microparticle properties and cells is poorly understood because there lationship between chemical and physical particle surface properties, protein adsorption and cell response remain unclear. Protein adsorption on a polymer particle surface is a complex phenomenon that is affected by different interfacial mechanisms/forces (e.g. DLVO and non-DLVO forces) and inherents tructural properties of macromolecules (e.g. polymers, surfactants, peptides and proteins) present on surface, establishing the parameters that involves inprotein/peptide adsorption on microparticles insights the logical design of the particles as a biomaterial useby contributing the understanding of another related complex phenomenon of the colloidal biomaterial-cell interface interaction in tissue engineering where limited study available to fully understand the concept.The purpose of this study is to investigate the impact of different formulation approaches on the physicochemical properties of the microparticles and identify connections between the particle properties, protein adsorption and ensuing cell response on these materials. To examine these, two different polymertypes (PLGA and PLGA-P188-PLGA) and two different emulsion stabilizers; a polymeric surfactant (PVA(Polyvinyl alcohol) and a polar oil propylene glycol were used to prepare four different types of particles in an emulsion process (O/W). Particles were characterized in terms of size, charge, topography, morphology and surface chemistry to identify the effect of the variables of polymer chemistry and use of surfactant on particle properties in first part of the study. Spin coated flatpolymer surfaces were generated to understand the interactions between the polymers and the proteins (fibronectin /poly-d-Lysine).

Particles and macromolecular components, including biopolymers (protein and carbohydrate), are viewed as the main foulants in the complex feed submerged membrane filtration systems such as membrane bioreactor (MBR). This work focused on two aspects of fouling in complex fluids: 1- Assessing fouling propensity and mechanisms for various model solutions. 2- Using of two specific solutions modelling biomass found in MBR for a better understanding of the fouling mechanisms in submerged MBR processes. Filtrations were carried out with 0.22 ??m PVDF hollow fibre membrane. Alginate was used as a model for polysaccharide, bovine serum albumin (BSA) as a model for protein, (un)washed yeast and bentonite were representing suspended solid contents. According to the data obtained during this study the fouling propensity of each model solution was classified as follow in a decreasing order: Alginate &gt unwashed yeast &gt washed yeast &gt BSA &gt bentonite for one-component solutions; and Alginate-washed yeast &gt Alginate-BSA &gt Alginate-bentonite &gt Alginate-unwashed yeast for two-component solutions. Introducing the alginate increased the reversible fouling (except BSA). Passive adsorption had a significant effect on fouling of alginate even before the beginning of the filtration. Washed yeast and a mixture of washed yeast + BSA were then used as model solutions to simulate the activated sludge found in MBR. The concentration of washed yeast and BSA used in this study were calculated in order for the characterisations of the two model solution to match (in terms of biopolymer contents) those of MBR biomasses reported in the literature. By rinsing, backwashing and chemical cleaning of the membrane, three fouling layers of upper, intermediate and lower were defined respectively. Results obtained from the analysis of the biopolymers found in the cleaning solutions allow a better understanding of the fouling mechanisms occurring for the two model solutions used in this study: for washed yeast, the lower layer and for washed yeast + BSA , the upper and intermediate layers were found to have relatively high biopolymeric composition. This was explained by higher concentration of solids on the membrane surface and by higher biopolymer interactions when washed yeast was mixed with BSA.

This thesis systematically investigates the effects of a recently developed modified ageing procedure of aluminium alloys, termed the T6I6 temper, on the microstructural development and mechanical properties of the Al ??? Mg ??? Si - Cu alloy 6061. For the T6I6 temper, a conventional single stage T6 temper is interrupted by an ageing period at a reduced temperature (65??C) to facilitate secondary precipitation, before resuming the final ageing at the temperature of the initial T6 treatment. The T6I6 temper was found to cause simultaneous increases in tensile properties, hardness, and toughness as compared with 6061 T6. Al ??? Mg ??? Si ??? Cu alloys are medium strength alloys widely used in the automotive industry and their further improvement is underpinned by stringent demands for weight reduction placed on the transportation industry in recent years. The potential for further improvement of the mechanical properties was found in the control of secondary precipitation that may take place even in some fully aged alloys when exposed to reduced temperatures. The overall improvement in the mechanical properties of 6061 T6I6 was attributed to the formation of finer and more densely dispersed precipitates in the final microstructure. The refinement of precipitates was facilitated by control of the precipitation processes and gradual evolution of the microstructure throughout each stage of the T6I6 treatment. The results indicated that the concentration and the chemical environment of the vacancies controlled the precipitation processes in this alloy. Findings also show that the proportion of the different precipitate phases present in the final microstructure, as well as the amount of the solute in these precipitates, can be controlled and modified utilizing secondary precipitation. A number of analytical techniques were used in this study. The evolution of the microstructure was studied using Transmission Electron Microscopy (TEM), High Resolution TEM (HRTEM) and Three Dimensional Atom Probe (3DAP). Vacancy-solute interactions were studied using Positron Annihilation Lifetime Spectroscopy (PALS) and 3DAP. The distribution of the solute was studied using 3DAP and Nuclear Magnetic Resonance (NMR). Differential Scanning Calorimetry (DSC) was used to identify precipitation reactions and to determine the stability of vacancy-associated aggregates.

The research programme studied the cure reaction of a phenolic novolak resin and the effects of various additives and fillers on the reaction. The programme utilised the recently developed thermal analysis technique of temperature-modulated differential scanning calorimetry (TMDSC) performed in conjunction with other available thermal analysis techniques. TMDSC enables the signal for the heat of reaction to be separated from the underlying specific heat change in the resin. This meant that the reaction could be studied without interference from any physical changes in the resin. The manufacture of composite brake materials required the use of numerous additives and fillers to produce the desired properties. The influence of such additives on the cure rate and final properties of the resin was known to occur but had not previously been measured due to the difficulties presented by the presence of opaque additives. Some additives also underwent thermally induced physical changes in the temperature range of the cure. The final properties and the processing of new brake materials undergoing development often required trial and error adjustments to compensate for changes in cure rate. An understanding of the influence of additives would enable more rapid commercial development of brake materials through an improvement in the ability to predict both the properties of the product and the optimal processing parameters. Processing efficiency could also be improved through detailed knowledge of the kinetics. Moulding cycle times and post-baking times and temperatures were longer than necessary in order to ensure adequate cure at the end of each stage because of the lack of kinetic data. The cure of phenolic resin has been shown to be highly complicated with numerous alternate and competing reactions. For the manufacture of composite materials, knowledge of the kinetic parameters of individual reactions is not considered to be important; rather the overall kinetic parameters are required for prediction. Therefore the kinetic model parameters that best described the observed behaviour were chosen even though the model had no basis in the molecular interaction theory of reaction. Rather it served as a convenient tool for predictions. Characterisation of the resin proved to be difficult due to the presence of overlapping peaks, and volatile reaction products. TMDSC was successfully used to determine the reaction kinetics of the pure resin and the influence of certain additives on the reaction kinetics. The determination of the kinetic parameters using TMDSC agreed well with the traditional Differential Scanning Calorimetry isothermal and non-isothermal techniques. Both the Perkin-Elmer and TA Instruments were utilised for the research and were found to provide reasonably good agreement with each other. The capabilities and limitations of the individual instruments were critically examined, frequently beyond the manufacturers' specifications. TMDSC suffers from a limitation in the heating rate of the sample compared to DSC. However, it was observed that valuable information could still be obtained from TMDSC despite using heating rates that were higher than specified by manufacturers. Hot Stage Microscopy and thermogravimetry were additional experimental techniques used to aid in the characterisation of the resin. Some inhomogeneity of the resin was identified as well as differences in the behaviour of the cure between open (constant pressure) and closed (constant volume) environments were observed. A novel method of determining the orders of the cure reactions and their kinetic parameters was utilised. Reaction models for the overall cure reactions were postulated and tested by fitment to sections of experimental data in temperature regions which appeared to be free of interference from overlapping peaks. Once an individual peak was reasonably well modelled, adjacent overlapping peaks were able to be modelled both individually and in combinations by fitment to experimental data. The Solver function in Microsoft Excel was utilised to find the best fitting model parameters for the experimental data. The model parameters were able to be refined as overlapping peaks were progressively incorporated into the calculations. This method produced results that agreed well with the traditional method of analysing reaction peak temperatures at multiple scanning rates. Model fitment was shown to be of benefit where overlapping reactions occur. Various model scenarios could be tested and optimised to particular sections of experimental data. This enabled the researcher to easily identify areas of possible anomalies and postulate alternative scenarios. The accuracy of the postulated model was able to be determined by its successful fitment to experimental data from experiments run under different conditions.

In this thesis a new approach for characterisation of digital mobile radio channels is investigated. The new approach is based on recognition of the fact that while the fading which is characteristic of the mobile radio channel is very rapid, the processes underlying this fading may vary much more slowly. The comparative stability of these underlying processes has not been exploited in system designs to date. Channel models are proposed which take account of the stability of the channel. Estimators for the parameters of the models are proposed, and their performance is analysed theoretically and by simulation and measurement. Bounds are derived for the extent to which the mobile channel can be predicted, and the critical factors which define these bounds are identified. Two main applications arise for these channel models. The first is the possibility of prediction of the overall system performance. This may be used to avoid channel fading (for instance by change of frequency), or compensate for it (by change of the signal rate or by power control). The second application is in channel equalisation. An equaliser based on a model which has parameters varying only very slowly can offer improved performance especially in the case of channels which appear to be varying so rapidly that the convergence rate of an equaliser based on the conventional model is not adequate. The first of these applications is explored, and a relationship is derived between the channel impulse response and the performance of a broadband system.

<p>Stora volymer förorenade sediment kommer att behöva tas om hand under de kommande åren då bottensediment i svenska farleder, hamn- och kustområden under lång tid har konta–minerats av både tungmetaller och organiska föroreningar. I examensarbetet studeras fyra möjligheter för hantering av förorenade muddermassor. De tre traditionella metoderna är <em>tippning till havs</em>, <em>utfyllnad i vik</em> eller <em>deponering på land</em>. <em>Stabilisering/solidifiering</em> (s/s) är ytterligare ett alternativ som innebär att muddermassorna kan nyttiggöras i geokonstruktioner genom att massornas hållfasthet ökas. Metoden går ut på att muddermassorna blandas med bindemedel och de eventuella föroreningarna binds då in i matrisen genom kemisk reaktion och fysikalisk inneslutning.  Syftet med examensarbetet är att, utifrån ett platsspecifikt perspektiv, undersöka hur föroreningsrisker kan jämföras mellan de fyra olika huvud–alternativen för hantering av muddermassor. Jämförelsen är tänkt att utgöra <em>en del</em> av ett beslutsunderlag som ska ligga till grund för valet av hanteringsalternativ.</p><p>Arbetet har fokuserat på miljöriskanalys och främst på hur risker kan <em>kategoriseras, värderas</em> och <em>jämföras</em>. Metoden inkluderar en litteraturstudie, en undersökning av tillstånds–ansökningar för hamnutbyggnad, en fallstudie där användning av LCA-metodik, ”ekotoxicitetspotential” och Naturvårdsverkets riktvärdesmodell testats för att jämföra föroreningsrisker mellan olika hanteringsalternativ i Oxelösunds hamn. Avslutningsvis genomfördes en serie intervjuer kring temat karaktärisering och jämförelser av risk i en s.k. Stakeholder Opinion Assessment (SOA).</p><p>I studien av tillståndsansökningarna för hamnutbyggnad konstaterades att jämförelser av platsspecifika föroreningsrisker mellan olika hanteringsalternativ för förorenade mudder–massor <em>inte görs.</em> Istället är det andra aspekter, t.ex. ekonomi, som avgör vilket alternativ som väljs. Varken ekotoxicitetspotential eller Naturvårdsverkets riktvärdesmodell visade sig vara lämpliga metoder för att beskriva och jämföra risker i det aktuella fallet. Av intervjuerna i SOA:n framgår att det råder delade meningar om hur risker ska beskrivas och på vilket sätt de kan jämföras och det finns ett stort behov av att utveckla nya sätt att beskriva och jämföra föroreningsrisker mellan olika alternativ och olika platser.</p><p>Arbetet har visat att det finns ett behov av att utveckla miljöriskanalysens avslutande steg, riskkaraktärisering och riskvärdering, eftersom det idag inte finns några konkreta metoder för att jämföra föroreningsrisker mellan olika hanteringsalternativ för förorenade muddermassor. För att förbättra beslutsunderlag föreslås därför en tydligare problemformulering och att övergripande platsspecifika scenarion för de olika alternativen tas fram. Viktigt aspekter att tydliggöra är skyddsobjekt, tidsskala, spridning och exponering. Jämförelsen av platsspecifika föroreningsrisker får inte heller bli allt för detaljerad, eftersom den bara är en del av ett större beslutsunderlag.</p> / <p>Large amounts of contaminated sediment has to be taken care of within the next few years since the sediment in Swedish sea lanes, ports and coastal areas have been contaminated by both heavy metals and organic pollutants over a long time period. Four options for handling contaminated dredged material were studied within this master thesis project. The three traditional methods are dumping the dredged material at sea, filling a bay with dredged material or putting the dredged material on a land disposal. Stabilization/solidification (s/s) is another option, where the contaminated dredged sediments are mixed with a binder that gives them greater strength, while immobilizing contaminants through chemical reactions or physical confinement in the structure. The aim of this thesis is to examine how risks of contamination can be compared between the four main options for management of dredged materials, in a site-specific perspective.</p><p>The main tool in the project has been environmental risk assessment with special focus on how risks can be categorized, measured and compared. The study includes a literature review, an examination of permit applications for port development, a case study where the LCA methodology, "potential eco-toxicity" and the Swedish Environmental Protection Agency's guideline value model was tested in order to compare the risks of contamination from the various management options in the port of Oxelösund. Finally a Stakeholder Opinion Assessment (SOA), by the theme risk characterization and risk comparison, was made.</p><p>The study of permit applications for port expansion has shown that the site-specific risks of contamination are not considered when choosing between management options of dredged materials. Instead other aspects, such as economy, determine the option chosen. Neither potential of eco-toxicity or the Swedish Environmental Protection Agency's guideline value model proved to be appropriate methods in order to describe and compare the risks associates with this case. The interviews in the SOA show that people disagree on how risks should be described and compared. There is a demand for new methods of describing and comparing risks associated with different management options for dredged materials at different sites.</p><p>This work has shown that well-known methods on how to compare risks of contamination between the different management options for contaminated dredged materials do not exist. There is also a need of developing the latter steps in the environmental risk assessment. To develop a better decision basis, a more explicit definition of the problem is proposed. It is particularly important to make site-specific descriptions of the various systems to be compared. The comparison of the site-specific risks of contamination should not be too detailed, since it is part of a larger decision support.</p> / Stabcon

This thesis is focused on the novel wood chip refining process called AdvancedThermomechanical Pulp (ATMP) refining. ATMP consists of mechanical pretreatmentof chips in Impressafiner and Fiberizer prior to first stage refining atincreased intensity. Process chemicals (this study was concentrated on hydrogenperoxide and magnesium hydroxide) are introduced into the first stage refiner.It is known that the use of chemicals in TMP process and first stage refining atelevated intensity can reduce the energy demands of refining. The downside is thatthey also alter the character of the produced pulp. Reductions in fibre length andtear index are usually the consequences of refining at elevated intensity. Additionof chemicals usually leads to reduction of the light scattering coefficient. Usingstatistical methods it was shown that it is possible to maintain the TMP character ofthe pulp using the ATMP process. This is explained by a separation of thedefibration and the fibre development phases in refining. This separation allowsdefibration of chips to fibres and fibre bundles without addition of chemicals orincrease in refining intensity. Chemicals are applied in the fibre developmentphase only (first stage refiner). The energy demand in refining to reach tensileindex of 25 Nm/g was reduced by up to 1.1 MWh/odt (42 %) using the ATMPprocess on Loblolly pine. The energy demand in refining of White spruce, requiredto reach tensile index of 30 Nm/g, was reduced by 0.65 MWh/odt (37%).Characterizations of individual fibre properties, properties of sheets made fromlong fibre fractions and model fibre sheets with different fines fractions werecarried out. It was established that both the process equipment configuration (i.e.the mechanical pre‐treatment and the elevated refining intensity) and the additionof process chemicals in the ATMP process influence fibre properties such as external and internal fibrillation as well as the amount of split fibres. Improvementof these properties translated into improved properties of sheets, made from thelong fibre fractions of the studied pulps. The quality of the fines fraction alsoimproved. However, the mechanisms of improvement in the fines quality seem tobe different for fines, generated using improved process configuration andaddition of process chemicals. The first type of fines contributed to better bondingof model long fibre sheets through the densification of the structure. Fines whichhave been influenced by the addition of the process chemicals seemed in additionto improve bonding between long fibres by enhancing the specific bond strength.The improved fibre and fines properties also translated into better airpermeability and surface roughness of paper sheets, properties which areespecially important for supercalendered (SC) printing paper. The magnitude offibre roughening after moistening was mainly influenced by the processequipment configuration while the addition of process chemicals yielded lowestfinal surface roughness due to the lowest initial surface roughness. There was nodifference in how fines fractions from the studied processes influenced the fibreroughening. However, fines with better bonding yielded model fibre sheets withhigher PPS, probably due to their consolidation around fibre joints. Hence, thedecrease in PPS can probably be attributed to the improvements in the long fibrefraction properties while the improvement of fines quality contributed to thereduction of air permeability.The process chemicals, utilized in the ATMP process (Mg(OH)2 and H2O2) alsoproved to be an effective bleaching system. Comparable increases in brightnesscould be reached using the ATMP process and conventional tower bleaching.Maximum brightness of the pulp was reached after approximately 10 minutes ofhigh‐consistency storage after refining or 40 minutes of conventional bleaching.This study was conducted using a pilot scale refiner system operated as a batchprocess. Most of the experiments were performed using White spruce (Piceaglauca). In Paper I, Loblolly pine (Pinus taeda) was used. It is believed that theresults presented in this thesis are valid for other softwood raw materials as well,but this limitation should be considered.

This study is aimed at investigating the feasibility of using the radiometric technique as an alternative to traditional methods for determining soil physico-chemical parameters which are important for terroir characterization. In-situ and ex-situ radiometric analyses of soil from three vineyard blocks of Simonsig Wine Estate in the Stellenbosch district (Western Cape, South Africa) were studied. A mobile MEDUSA gamma-ray detection system comprising a CsI(Na) crystal (length 15 cm, diameter 7 cm) and associated electronics mounted on a portable trolley were used for partial terroir characterisation. Thereafter activity concentrations of 40K, 232Th series and 238U series in soil (top ~30 cm) from the measured MEDUSA spectra (0 – 3 MeV) were extracted by means of the full-spectrum analysis (FSA) method. A lead-shielded HPGe detector was used for analyzing collected soil samples while soil physico-chemical parameters were analysed using standard methods at research and commercial laboratories.