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  • Public defence: 2020-06-15 09:30 https://kth-se.zoom.us/s/69079443003
    Hongyu, Jin
    KTH, School of Electrical Engineering and Computer Science (EECS), Computer Science, Communication Systems, CoS.
    Cooperative Privacy and Security for Mobile Systems2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The growing popularity of powerful mobile devices, along with increased computation and storage of computing infrastructure, opened possibilities for versatile mobile system applications. Users, leveraging sensing capabilities of the devices, can collect rich data and exchange the data with diverse Service Providers (SPs) or their close neighboring devices. Provision of such user status awareness to the involved system entities, can facilitate customized user experience for system participants.

    Nonetheless, the open and decentralized nature of mobile systems raise concerns on both security and privacy of users and the system infrastructure. Sensitive user data could be exposed to honest-but-curious entities, which can further process data to profile users. At the same time, compromised system entities can feed faulty data to disrupt system functionalities or mislead users. Such issues necessitate secure and privacy-enhancing mobile systems, while not compromising the quality of service the systems provide to their users. More specifically, the solutions should be efficient and scale as the system grows, and resilient to both external and internal adversaries. This thesis considers two mobile system instances: Location-based Services (LBSs) and Vehicle-to-Vehicle (V2V) safety applications. We address security and privacy in a cooperative manner, relying on cooperation among the users to protect themselves against the adversaries. Due to the reliance on peers, input from the peers should be examined, in order to ensure the reli- ability of the applications. We adapt pseudonymous authentication, designed for Vehicular Communication (VC) systems, and integrate it with LBSs. This protects user privacy and holds users accountable for their actions, which are non-repudiable. At the same time, our scheme prevents malicious nodes from aggressively passing on bogus data. We leverage redundancy of shared data from multiple cooperating nodes to detect potential conflicts. Any conflict triggers proactive checking on the data with the authoritative entity that reveals the actual misbehaving users. For V2V safety applications, we extend safety beacons, i.e., Cooperative Awareness Messages (CAMs), to share signature verification effort, for more efficient message verification. Similarly to the LBSs, redundancy of such piggybacked claims is also key for remedying malicious nodes that abuse this cooperative verification. In addition, the extended beacon format facilitates verification of event-driven messages, including Decentralized Environmental Notification Messages (DENMs), leveraging proactive authenticator distribution.

    We qualitatively and quantitatively evaluate achieved security and privacy protection. The latter is based on extensive simulation results. We propose a location privacy metric to capture the achieved protection for LBSs, taking into consideration the pseudonymous authentication. The performance of the privacy-enhancing LBS is experimentally evaluated with the help of an implementation on a small scale automotive computer testbed. We embed processing delays and queue management for message processing in simulations of V2V communication, to show scalability and efficiency of the resilient V2V communication scheme. The results confirm the resilience to both internal and external adversaries for the both systems.

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  • Agerbeg, Jens
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Mathematical Statistics.
    Statistical Learning and Analysis on Homology-Based Features2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Stable rank has recently been proposed as an invariant to encode the result of persistent homology, a method used in topological data analysis. In this thesis we develop methods for statistical analysis as well as machine learning methods based on stable rank. As stable rank may be viewed as a mapping to a Hilbert space, a kernel can be constructed from the inner product in this space. First, we investigate this kernel in the context of kernel learning methods such as support-vector machines. Next, using the theory of kernel embedding of probability distributions, we give a statistical treatment of the kernel by showing some of its properties and develop a two-sample hypothesis test based on the kernel. As an alternative approach, a mapping to a Euclidean space with learnable parameters can be conceived, serving as an input layer to a neural network. The developed methods are first evaluated on synthetic data. Then the two-sample hypothesis test is applied on the OASIS open access brain imaging dataset. Finally a graph classification task is performed on a dataset collected from Reddit.

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  • Public defence: 2020-06-15 10:00 Online via Zoom (public)
    Korkovelos, Alexandros
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    Advancing the state of geospatial electrification modelling: New data, methods, applications, insight and electrification investment outlooks2020Doctoral thesis, comprehensive summary (Other academic)
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  • Public defence: 2020-06-12 09:00 https://kth-se.zoom.us/j/62560073937
    Remnestål, Julia
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Affinity Proteomics.
    Dementia Proteomics2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The term dementia encompass a number of conditions arising as a consequence of tissue degeneration in the brain. This degeneration is caused by molecular events occurring on a cellular level including inflammation, defective waste disposal and accumulation of insoluble proteins and peptides. Many of these molecular events are in turn also reflected in the composition of the cerebrospinal fluid (CSF) which circulates within and around the brain. This thesis summarise five studies conducted with the aim to explore and profile CSF proteins in the context of dementia and other neurodegenerative disorders. Protein profiles were obtained by so-called suspension bead arrays (SBAs), created by coupling antibodies to color-coded microspheres, allowing detection of more than 350 CSF proteins simultaneously. The majority of the explored proteins are referred to as brain-enriched, entailing that the corresponding genes are highly expressed in brain tissue in comparison to other tissues.

     

    In Paper I, the SBA technology was utilised to profile about 280 proteins in CSF from several neurodegenerative disorders, i.e. Alzheimer’s disease (AD), dementia with Lewy Bodies and Parkinson’s disease. Distinct differences in the CSF proteome were identified depending on site of collection (ventricular or lumbar) and time point (post mortem or ante mortem). Disease-associated profiles for the two synaptic proteins neuromodulin (GAP43) and neurogranin (NRGN) could be confirmed, in which both proteins displayed higher levels in AD compared to controls. High levels of the two proteins were furthermore observed in patients at preclinical stages of AD in two independent cohorts. To verify the identified protein profiles, parallel reaction monitoring (PRM) assays were developed for 17 proteins in Paper II, including GAP43. Eight proteins displayed concordance to data generated with SBAs and among these were GAP43, cholecystokinin, neurofilament medium chain (NF-M), leucine-rich alpha-2-glycoprotein and vascular cell adhesion protein 1. 

     

    In Paper III, the SBA technology was again applied to characterise early dementia-related changes in the CSF proteome by comparing samples from individuals with mild cognitive impairment (MCI), controls and AD patients in two independent cohorts. The MCI individuals were moreover stratified based on CSF concentration of the core AD biomarkers Aβ42 and tau. The six proteins amphiphysin, aquaporin 4, cAMP regulated phosphoprotein 21, β-synuclein, GAP43 and NF-M did all show significant differences between sample groups in both cohorts. Further exploration of how the pathological processes preceding dementia affect the CSF proteome, was done by analysis of 104 brain-enriched proteins in CSF from asymptomatic 70 year-olds in Paper IV. Protein profiles were correlated to Aβ42, t-tau and p-tau CSF concentration, revealing a large number of proteins displaying significant correlations to tau levels. Upon dividing the asymptomatic individuals based on Aβ42 CSF pathology, some proteins showed significantly different associations in the two groups. Most of these proteins yielding interesting profiles, were plasma membrane proteins or proteins connected to synaptic vesicle transport.

     

    While AD is the most common form of dementia, accounting for more than 60 % of all cases worldwide, frontotemporal dementia (FTD) is the most frequently occurring form of young-onset dementia. In Paper V, CSF protein profiles were explored in the context of FTD. Patients with behavioural variant FTD and primary progressive aphasia, were compared to unaffected individuals with a high risk of developing FTD. Proteomic differences between patients with FTD and the unaffected individuals were observed already at a global level, and particularly for the six proteins NF-M, neurosecretory protein VGF, neuronal pentraxin receptor, prodynorphin, transmembrane protein 132D and tenascin-R.

     

    The disease-associated profiles identified in the presented studies provide a basis for future research within dementia proteomics. Whether the proteins identified will have the possibility to aid in clinical diagnosis, prognosis or characterisation of dementia, remains to be evaluated. Given the fortunate situation, especially in Sweden, with access to large and well characterised CSF collections, there are ample opportunities for future proteomic studies to elucidate the true potential of these proteins.

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    Dementia Proteomics Kappa Remnestaal
  • Public defence: 2020-06-12 14:00 Publikt via ZOOM
    Szipka, Károly
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Uncertainty Management for Automated Diagnostics of Production Machinery2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Neither production machinery, nor production systems will ever become completely describable or predictable. This results in the continuous need for monitoring and diagnostics of such systems in order to manage related uncertainties. In advanced production systems uncertainty has to be the subject to a systematic management process to maintain machine health and improve performance. Automation of diagnostics can fundamentally improve this management process by providing an affordable and scalable information source. In this thesis, the important aspects of uncertainty management in production systems are established and serve as a basis for the composition of an uncertainty-based machine diagnostics framework. The proposed framework requires flexible, fast, integrated and automated diagnostics methods. An inertial measurement-based test method is presented in order to satisfy these requirements and enable automated measurements for diagnostics of production machinery. The gained insights and knowledge about production machine health and capability improve transparency, predictability and dependability of production machinery and production systems. These improvements lead to increased overall equipment effectiveness and higher level of sustainability in operation.

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  • Public defence: 2020-06-12 13:00 FB42, Stockholm
    Capel, Francesca
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Cosmic clues from astrophysical particles2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Ultra-high-energy cosmic rays (UHECRs) are charged particles that have been accelerated to extreme energies, such that they are effectively travelling at the speed of light. Interactions of these particles with the Earth’s atmosphere lead to the development of extensive showers of particles and radiation that can be measured with existing technology. Despite decades of research, the origins of UHECRs remain mysterious. However, they are thought to be accelerated within powerful astrophysical sources that lie beyond the borders of our Galaxy. This thesis explores different ideas towards the common goal of reaching a deeper understanding of UHECR phenomenology. Part I concerns the development of a novel space-based observatory that has the potential to detect unprecedented numbers of these enigmatic particles. The feasibility of such a project is demonstrated by the results from the Mini-EUSO instrument, a small ultraviolet telescope that is currently on-board the International Space Station. In Part II, the focus is on fully exploiting the available information with advanced analysis techniques to close the gap between theory and data. UHECRs are closely connected to the production of neutrinos and gamma rays, so frameworks for the joint analysis of these complementary cosmic messengers are also developed. The results presented herein demonstrate that to progress, it is crucial to invest in the development of both detection and analysis techniques. By taking a closer look at the existing data, new clues can be revealed to reach a more comprehensive understanding and better inform the design of future experiments. 

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  • Public defence: 2020-06-12 10:00 Zoom
    Berggren, Tomas
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.).
    On determinantal point processes and random tilings with doubly periodic weights2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is dedicated to asymptotic analysis of determinantal point processes originating from random matrix theory and random tiling models. Our main interest lies in random tilings of planar domains with doubly periodic weights.

    Uniformly distributed random tiling models are known to be a very rich class of models where many interesting phenomena can be observed. These models have therefore been under investigation for many years and many aspects of the models are by now well understood. Random tiling models with doubly periodic weights are in fact an even richer class of models. However, these models are much more difficult to analyze and for a thorough study of their behavior new ideas are needed. This thesis increases the understanding of random tiling models with doubly periodic weights.

    The thesis consists of three papers and two chapters; one introductory and background chapter and one chapter giving an overview of the papers.

    Paper A deals with linear statistics of the thinned Circular Unitary Ensemble and the thinned sine process. The thinning creates a transition from the Circular Unitary Ensemble respectively sine process to the Poisson process. We study a part of these transitions in detail.

    In Papers B and C we study random tiling models with doubly periodic weights. These two papers constitute the main contribution of this thesis.

    In Paper B we give a general method how to analyze a large family of random tiling models. In particular, we provide a double integral formula for the correlation kernel in terms of a Wiener-Hopf factorization of an associated matrix-valued function. We also present a recursive method on how to construct the Wiener-Hopf factorization.

    The method developed in Paper B is used in Paper C to analyze the 2×k-periodic Aztec diamond. More precisely, we derive the correlation kernel for the Aztec diamond of finite size and give a detailed description of the model as the size tends to infinity.

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  • Public defence: 2020-06-05 10:00 https://kth-se.zoom.us/s/68861340458
    Berglund, Emelie
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Gene Technology.
    Molecular and Spatial Profiling of Prostate Tumors2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Every cancer tumor is unique, with characteristics that change over time. The evolution of a full-blown malignancy from a single cell that gives rise to a heterogeneous population of cancer cells is a complex process. The use of spatial information makes a big contribution to understanding the progression of tumors and how patients respond to treatment. Currently, the scientific community is taking a step further in order to understand gene expression heterogeneity in the context of tissue spatial organization to shed light on cell- to-cell interactions. Technological advances in recent years have increased the resolution at which heterogeneity can be observed. Spatial transcriptomics (ST) is an in situ capturing technique that uses a glass slide containing oligonucleotides to capture mRNAs while maintaining the spatial information of histological tissue sections. It combines histology and Illumina sequencing to detect and visualize the whole transcriptome information of tissue sections. In Paper I, an AI method was developed to create a computerized tissue anatomy. The rich source of information enables the AI method to identify genetic patterns that cannot be seen by the naked eye. This study also provided insights into gene expression in the environment surrounding the tumor, the tumor microenvironment, which interacts with tumor cells for cancer growth and progression. In Paper II, we investigate the cellular response of treatment. It is well known that virtually all patients with hormone naïve prostate cancer treated with GnRH agonists will relapse over time and that the cancer will transform into a castration-resistant form denoted castration-resistant prostate cancer. This study shows that by characterizing the non-responding cell populations, it may be possible to find an alternative way to target them in the early stages and thereby decrease the risk of relapse. In Paper III, we deal with scalability limitations, which in the ST method are represented by time- consuming workflow in the library preparation. This study introduces an automated library preparation protocol on the Agilent Bravo Automated Liquid Handling Platform to enable rapid and robust preparation of ST libraries. Finally, Paper IV expands on the first work and illustrates the utility of the ST technology by constructing, for the first time, a molecular view of a cross-section of a prostate organ.

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  • Niewalda, Tobias
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Deep Learning Based Classification of Rail Defects Using On-board Monitoring in the Stockholm Underground2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this work is to find out if an artificial neural network can be useful purpose of this work is to find out if an artificial neural network can be useful in order to detect rail squats with the existing Quiet Track Measurement System (QTMS). Squats are surface-initiated rail defects which arise due to rolling contact fatigue. The monitoring system, installed on seven trains running on the green line in the Stockholm underground, aims to improve the maintenance process. The early detection and surveillance of defects helps to extend the service life of the tracks and reduce operating costs. An artificial neural network is used to analyse the the continuously recorded measurements, which consist of vertical bogie acceleration and surrounding noise, each sampled with a frequency of 22 kHz.In particular, the power spectral density as input for multi-layer Fully-connected Neural Network (FNN) has proven to be promising for accurate squat predictions. The supervised learning was carried out according to the one-vs-all principle, i.e. squats versus all other events. A two-hidden-layer FNN has finally been chosen to complement the QTMS. The usage of the full available frequency range from almost DC up to 11kHz, but minimum 7 kHz, allows good prediction with only low false prediction rates. When concatenating all six measurement channels to a single classifier input, an accuracy of over 96% for the squat class and up to 99.98% can in total be achieved. The chosen network type also showed high stability despite quite strong parameter variations and a massive under-representation of squat observations in the measurement data.However, since limited maintenance information about actual squats is available for labelling and testing, more evaluation is needed. The correct identification of mis-labelled squats indicates the high potentials of artificial neural networks.

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  • Public defence: 2020-06-10 15:15 A5:1003, Stockholm
    Samuelsson, Filip
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. Oskar Klein Ctr Cosmoparticle Phys, SE-10691 Stockholm, Sweden..
    Multi-messenger emission from gamma-ray bursts2020Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Multi-messenger astronomy is a very hot topic in the astrophysical community. A messenger is something that carries information. Different astrophysical messenger types are photons, cosmic rays, neutrinos, and gravitational waves. They all carry unique and complementary information to one another. The idea with multi-messenger astronomy is that the more different types of messengers one can obtain from the same event, the more complete the physical picture becomes.

    In this thesis I study the multi-messenger emission from gamma-ray bursts (GRBs), the most luminous events known in the Universe. Specifically, I study the connection of GRBs to extremely energetic particles called ultra-high-energy cosmic rays (UHECRs). UHECRs have unknown origin despite extensive research. GRBs have long been one of the best candidates for the acceleration of these particles but a firm connection is yet to be made. In Paper I and Paper II, we study the possible GRB-UHECR connection by looking at the electromagnetic radiation from electrons that would also be accelerated together with the UHECR. My conclusion is that the signal from these electrons does not match current GRB observation, disfavoring that a majority of UHECRs comes from GRBs.

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  • Public defence: 2020-06-12 09:30 D5, Stockholm
    Yu, Peng
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Power Safety.
    Modelling and Simulation of Reactor Pressure Vessel Failure during Severe Accidents2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis aims at the development of new coupling approaches and new models for the thermo-fluid-structure coupling problem of reactor pressure vessel (RPV) failure during severe accidents and related physical phenomena. The thesis work consists of five parts: (i) development of a three-stage creep model for RPV steel 16MND5, (ii) development of a thermo-fluid-structure coupling approach for RPV failure analysis, (iii) performance comparison of the new approach that uses volume loads mapping (VLM) for data transfer with the previous approach that uses surface loads mapping (SLM), (iv) development of a lumped-parameter code for quick estimate of transient melt pool heat transfer, and (v) development of a hybrid coupling approach for efficient analysis of RPV failure.

    A creep model called ‘modified theta projection model’ was developed for the 16MND5 steel so that it covers three-stage creep process. Creep curves are expressed as a function of time with five parameters  (i=1~4 and m) in the new creep model. A dataset for the model parameters was constructed based on the available experimental creep curves, given the monotonicity assumption of creep strain vs temperature and stress. New creep curves can be predicted by interpolating model parameters from this dataset, in contrast to the previous method that employs an extra fitting process. The new treatment better accommodates all the experimental curves over the wide ranges of temperature and stress loads. The model was implemented into the ANSYS Mechanical code, and its predictions successfully captured all three creep stages and a good agreement was achieved between the experimental and predicted creep curves. For dynamic loads that change with time, the widely used time hardening and strain hardening models were implemented with a reasonable performance. These properties fulfil the requirements of a creep model for structural analysis.

    A thermo-fluid-structure coupling approach was developed by coupling the ANSYS Fluent for the fluid dynamics of melt pool heat transfer and ANSYS Structural for structural mechanics of RPV. An extension tool was introduced to realize transient load transfer from ANSYS Fluent to Structural and minimize the user effort. Both CFD with turbulence models and the effective model PECM can be employed for predicting melt pool heat transfer. The modified theta projection model was used for creep analysis of the RPV. The coupling approach does not only capture the transient thermo-fluid-structure interaction feature, but also support the advanced models in both melt pool convection and structural mechanics to improve fidelity and facilitate implementation. The coupling approach performs well in the validation against the FOREVER-EC2 experiment, and can be applied complex geometries, such as a BWR lower head with forest of penetrations (control rod guide tubes and instrument guide tubes).

    In the comparative analysis, the VLM and SLM coupling approaches generally have the similar performance, in terms of their predictability of the FOREVER-EC2 experiment and applicability to the reactor case. Though the SLM approach predicted slightly earlier failure times than VLM in both cases, the difference was negligible compared to the large scale of vessel failure time (~  s). The VLM approach showed higher computational efficiency than the SLM.

    The idea of the hybrid coupling is to employ a lumped-parameter code for quick estimate of thermal load which can be employed in detailed structural analysis. Such a coupling approach can significantly increase the calculation efficiency which is important to the case of a prototypical RPV where mechanistic simulation of melt pool convection is computationally expensive and unnecessary. The transIVR code was developed for this purpose, which is not only capable of quick estimate of transient heat transfer of one- and two- layer melt pool, but also solving heat conduction problem in the RPV wall with 2D finite difference method to provide spatial thermal details for RPV structural analysis. The capabilities of transIVR in modelling two-layer pool heat transfer and transient pool heat transfer were demonstrated by calculations against the UCSB FIBS benchmark case and the LIVE-7V experiment, respectively. The transIVR code was then coupled to the mechanical solver ANSYS Mechanical for detailed RPV failure analysis. Validation against the FOREVER-EC2 experiment indicates the coupling framework successfully captured the vessel creep failure characteristics.

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  • Public defence: 2020-06-10 10:00 online via Zoom
    Wang, Bochao
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL.
    Constitutive models of magneto-sensitive rubber under a continuum mechanics basis and the application in vibration isolation2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Due to its durability, stretchability, relatively low stiffness and high damping, rubber is widely used in engineering anti-vibration fields. However, a major deficiency is that once installed, the mechanical properties of traditional rubber-based devices are fixed where its adaptability to various loading conditions is poor. An alternative to traditional rubber materials is magneto-sensitive (MS) rubber. The main componentsof MS rubber are a rubber matrix and ferromagnetic particles. Under a magnetic field, the modulus of MS rubber can be altered rapidly and reversibly. Therefore, compared with conventional rubber-based devices, the stiffness of MS rubber-based devices can be adapted to various loading conditions and an enhanced vibration reduction effect can be achieved. Measurement results revealed that the mechanical behavior of MS rubber is not simple. To be specific, the dynamic modulus of MS rubber has a magnetic, frequency,amplitude and temperature dependency. In order to promote the applications of MS rubber in the anti-vibration area, models to depict the above properties are needed. The main goal of this thesis is to model the magnetic, frequency, amplitude and temperature dependence of MS rubber under a continuum mechanics basis. The research results regarding the constitutive modeling consist of three papers (Paper A, C and D). The simulation results show a good agreement with the measurement data, which proves the accuracy and feasibility of the developed model. In addition to the constitutive models of MS rubber, an investigation of MS rubber application in the vibration isolation system under harmonic and random loading cases is numerically conducted (Paper B). In order to achieve an enhanced vibration isolation effect, two control algorithms corresponding to the harmonic and random loading are developed. Numerical results verify that the vibration isolation effect ofMS rubber vibration isolator is better than the traditional rubber-based isolator. In this thesis, the model developed for MS rubber deepens the understanding of how magnetic, frequency, amplitude and temperature affect the mechanical performance of MS rubber. Moreover, the research of MS rubber application in vibration isolators and the corresponding control strategies are helpful for the design of MS rubber-based anti-vibration devices.

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    Constitutive models of magneto-sensitive rubber under a continuum mechanics basis and the application in vibration isolation
  • Public defence: 2020-08-18 13:00 Videolänk kommer / Video link is forthcoming, Stockholm
    de Frias Lopez, Ricardo
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    DEM Modelling of Unbound Granular Materials for Transport Infrastructures: On soil fabric and rockfill embankments2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Unbound granular materials (UGM) are widely used as load-bearing layers and for embankment construction within transport infrastructures. These play a significant role on operation and maintenance of transportation systems. However, pavement and railway engineering still today rely heavily on empirical models based on macroscopic observations. This approach results in limited knowledge on the fundamentals at particle scale dictating the macroscopic response of the material. In this sense, the discrete element method (DEM) presents a numerical alternative to study the behaviour of discrete systems with explicit consideration of processes at particulate level. Additionally, it allows obtaining information at particulate level in a way that cannot be matched by traditional laboratory testing. All of this, in turn, can result in greater micromechanical insight.This thesis aims at contributing to the body of knowledge of the fundamentals of granular matter. UGM for transport infrastructures are studied by means of DEM in order to gain insight on their response under cyclic loading. Two main issues are considered: (1) soil fabric and its effect on the performance of coarse-fine mixtures and (2) modelling of high rockfill railway embankments. Among the main contributions of this research there is the establishing of a unified soil fabric classification system based exclusively on force transmission considerations that furthermore correlates with performance. In particular, fabrics characterized by a strong interaction between the coarse and fine fractions resulted in improved performance. A soil fabric type with a potential for instability was also identified. Regarding embankments, DEM modelling shows that traffic induced settlements accumulate on the top layers and therefore seem to be unaffected by embankment height above a certain value. A marked influence of degradation, even considering its nearly negligible magnitude, was observed, largely resulting in increased settlements.

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  • Public defence: 2020-06-11 13:00 Via Zoom -- https://kth-se.zoom.us/meeting/register/u5Isf--grTguHNPDOGMrkrpy5nka38XCSnZG, Stockholm
    Quino Lima, Israel
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering. Universidad Mayor de San Andres.
    Hydrogeochemistry and spatial variability of arsenic and other trace elements in the Lower Katari Basin around Lake Titicaca, Bolivian Altiplano.: Impact on drinking water quality and groundwater management.2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Arsenic (As) contamination in drinking water is a world-wide problem. Thenatural origin of As, its mobility and transport are of great interest in BolivianAltiplano (Lower Katari Basin: LKB and Sothern Poopó Basin: SPB) due topresence of mineral ore deposits, brines, hot springs and volcanic rocks.Hydrogeochemical spatio-temporal and spatial variability investigations wereapplied to groundwater, surface water and sediments with a statistical approachto better understand the spatial distribution of As, major ions and trace elements,and evaluate the sources of dissolved species and elucidate the processes thatgovern the evolution of natural water in the LKB. The result reveal high levelsof As, boron (B), antimony (Sb), manganese (Mn) and salinity in shallow wells,which exceeds the guideline values of the Bolivian regulation (NB-512) andWorld Health Organization (WHO). The seasonal variation and its impact onthe water quantity, on top of the solids and liquid residual (origin Pallina River)poses significant negative health risk for the community at the banks of theKatari River. The first evaluation of the hydrogeological study indicates that thegroundwater flow was observed in the direction southeast - northwest (SE -NW), and there is an interaction between groundwater and surface water. Thespatial distribution of As varies considerably due to geological characteristics ofthe area as well as due to the heterogeneously distributed evaporites in thesediments (in LKB and SPB). However, the highest concentrations of As arefound in the alluvial sediments of the northern region. Sequential extraction ofsediment along with geochemical modeling (mineral saturation indices) indicatesthat the iron (Fe) and aluminum (Al) oxides as well as their hydroxides are mostimportant adsorbent minerals of As in central and southern region of LKB. Thechemistry of water bodies in LKB and SPB is strongly influenced by theinteraction with the sediment constituents and by the spatial-temporal variations.The results of spatial analysis indicate that despite of the outliers there is a goodautocorrelation for As, B and Sb, since Moran's I values are positive. The globalspatial dependence analysis indicated a positive and statistically significant spatialautocorrelation (SA) for all cases and TEs are not randomly distributed at 99%confidence level.

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  • Public defence: 2020-06-09 09:00 https://kth-se.zoom.us/webinar/register/WN_qgz5ej_sQVOiEwrSoar3Ew, Stockholm
    Stefanikova, Estera
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Fusion Plasma Physics.
    Pedestal structure and stability in JET-ILW and comparison with JET-C2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Controlled thermonuclear fusion offers a promising concept for safe and sustainable production of electrical energy. However, there are still many issues to be investigated on the way to a commercial fusion reactor. An important point for detailed studies is connected to wall materials surrounding hot thermonuclear plasma. The JET tokamak (the largest fusion experiment in the world) in the United Kingdom has completed a major upgrade in 2011 in which the materials of the vessel surrounding the fusion fuel have been changed from a carbon-fibre-composite (or JET-C wall) to Beryllium and Tungsten. These new materials are the same as those that will be used in a next step fusion device International Thermonuclear Experimental Reactor ITER (hence the name ITER-like wall or JET-ILW), designed to demonstrate the feasibility of fusion reactor based on the tokamak concept. One of the goals of JET with the ILW is to act as a test bed for ITER technologies and for ITER operating scenarios.

    The overall purpose of the thesis work is to characterise the effect of the ILW on the structure and stability of edge plasma phenomenon called the pedestal, a steep pressure gradient associated with the H-mode, an operational regime with improved confinement. The aim is to contribute to the understanding of the difference in the pedestal performance between JET-C and JET-ILW.

    The work is focused on experimental characterisation of the pedestal structure in deuterium discharges by analysing the experimental data (radial profiles of electron temperature and density measured in H-mode plasmas) from Thomson scattering diagnostics at JET and on investigating the differences in pedestal stability between JET-ILW and JET-C plasmas in terms of the pedestal modelling. The pedestal structure is determined using a modified hyperbolic tangent fit to the experimental Thomson scattering profiles. The modelling is performed with the pedestal predictive code Europed, based on the EPED model commonly used to predict the pedestal height in JET.

    The experimental analysis has shown several differences in the pedestal structure of comparable JET-ILW and JET-C discharges. One of the key differences introduced in this work is the pedestal relative shift (a separation between the middle of the pedestals of the electron density and temperature) that plays a major role in the difference in the pedestal performance between JET-C and JET-ILW. The work shows that the relative shift can vary significantly from pulse to pulse and that, on average, JET-C plasmas have lower relative shift than JET-ILW plasmas. The pedestal relative shift tends to increase with increase in the gas fuelling and the heating power. Furthermore, the increase in the relative shift has been empirically correlated with the degradation of the experimental normalized pressure gradient αexp.

    To understand the differences in the JET-C and JET-ILW pedestal stability, parameters that affect the pedestal stability and that tend to vary between comparable JET-C and JET-ILW discharges have been identified. These parameters are the pedestal relative shift, pedestal density neped, effective charge number Zeff, pedestal pressure width wpe, and normalized pressure βN. The modelling performed with the predictive Europed code has shown that these five parameters are sufficient to explain the difference in the pedestal performance between JET-C and JET-ILW.

    Furthermore, the modelling has shown that the relative shift and neped play a major role in affecting the critical normalized pressure gradient αcrit (normalized pressure gradient expected by the model comparable to αexp), while the relative shift, wpe and Zeff have a major impact on the pedestal pressure height. Finally, a possible mechanism that has led to the degradation of the pedestal pressure from JET-C to JET-ILW is proposed.

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  • Public defence: 2020-06-12 14:00 U1, Stockholm
    Held, Manne
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering and Computer Science (EECS).
    Fuel-Efficient Look-Ahead Control for Heavy-Duty Vehicles with Varying Velocity Demands2020Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The fuel consumption of heavy-duty vehicles can be reduced by using information about the upcoming road section when controlling the vehicles. Most manufacturers of heavy-duty vehicles today offer such look-ahead controllers for highway driving, where the information consists of the road grade and the velocity only has small variations. This thesis considers look-ahead control for applications where the velocity of the vehicle has large variations, such as distribution vehicles or vehicles in mining applications. In such conditions, other look-ahead information is important, for instance legal speed limits and curvature. Fuel-efficient control is found by formulating and solving the driving missions as optimal control problems.

    First, it is shown how look-ahead information can be used to set constraints in the optimal control problems. A velocity reference from a driving cycle is modified to create an upper and a lower bound for the allowed velocity, denoted the velocity corridor. In order to prevent the solution of the optimal control problem from deviating too much from a normal way of the driving, statistics derived from data collected during live truck operation are used when formulating the constraints. It is also shown how curvature and speed limits can be used together with actuator limitations and driveability considerations to create the velocity corridor.

    Second, a vehicle model based on forces is used to find energy-efficient velocity control. The problem is first solved using Pontryagin's maximum principle to find the energy savings for different settings of the velocity corridor. The problem is then solved in a receding horizon fashion using a model predictive controller to investigate the influence of the control horizon on the energy consumption. The phasing and timing of traffic lights are then added to the available information to derive optimal control when driving in the presence of traffic lights.

    Third, the vehicle model is extended to include powertrain components in two different approaches. In a first approach, a Boolean variable is added to represent open or closed powertrain. This enables the vehicle to freewheel, in order to save fuel by reducing the losses due to engine drag. The problem is formulated as a mixed integer quadratic program. In a second approach, the full powertrain is modeled including a fuel map and a model of the gearbox losses, both based on measurements on real components. The problem is solved using dynamic programming, with transitions between states including gear shifts, freewheeling, and coasting in gear.

    Forth, the optimal control framework is used to implement an optimal control-based powertrain controller in a real Scania truck. The problem is first solved offline resulting in trajectories for velocity and freewheeling. These are used online in the vehicle as references to the existing controllers for torque and gear demands. Experiments are performed with fuel measurements, resulting in 16% fuel savings, compared to 18% savings by solving the optimal control problem.

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  • Mele, Giampaolo
    et al.
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Numerical Analysis, NA. KTH, Centres, SeRC - Swedish e-Science Research Centre.
    Ringh, Emil
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory. KTH, Centres, SeRC - Swedish e-Science Research Centre.
    Ek, David
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
    Izzo, Federico
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Numerical Analysis, NA.
    Upadhyaya, Parikshit
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Numerical Analysis, NA.
    Jarlebring, Elias
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Numerical Analysis, NA. KTH, Centres, SeRC - Swedish e-Science Research Centre.
    Preconditioning for linear systems2020Book (Other academic)
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  • Public defence: 2020-06-05 14:00 Publikt via ZOOM, Stockholm
    Törnblom, Oskar
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Organizational Design and Leadership Development: The Role of Increasing Complexity​2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Many organizations need to adapt to increasingly complex environments. New forms of organizational design and leadership are called for and, under some circumstances, more collective leadership practices are needed. Furthermore, values and beliefs in some societal contexts foster a general positive bias for collective leadership. Paradoxically, many investment decisions regarding leadership development activities do not pay off. At the same time, the research fields of collective leadership development and on-the-job leader development are underutilized. The research field of leadership is in need of consolidation and integration within and between research areas. There has been much less research done on collective leadership development compared with leader development, and research on leadership development has been focused more on individual and collective change rather than on contextual facilitating factors such as organizational design.

    To address these theoretical and practical challenges, the aim of the thesis was to explore organizational design and leadership development in terms of increasing complexity in the empirical context of technology-, knowledge-, and project-intensive organizations. The research design was centered around two studies that were part of a larger interactive research project and two conceptual studies that jointly investigated (1) organizational design and increasing complexity, (2) leadership development and increasing complexity, (3) how increasingly complex organizational design can foster leadership development. The interactive research project had four goals in terms of creating common learning for the project partners involved, new academic knowledge, and organizational development not only for the participating organizations but also for organizations in general.

    The thesis contributes to the research fields of organizational design and leadership development as well as their intersection. It adds to theory by providing a more fine-grained definition of ways of understanding leadership development according to increasing complexity. Furthermore, it adds to the understanding of how increasingly complex organizational design can foster leadership development, especially collective leadership, thus demonstrating empirical examples of leadership development without traditional leadership development investments.

    The thesis proposes future research on emerging technology as an accelerator for leadership development and interactive research in partnership with organizations in order to further integrate the research fields of organizational design and leadership development. In terms of managerial contributions, a number of suggestions are offered to support better knowledge creation and decision-making regarding organizational design, on-the-job leader development, and especially collective leadership development. Furthermore, a shift from a psychology-centered leadership development approach toward more of a systemic and organizational design-centered leadership development approach that includes both individual and collective dimensions is called for. This shift will potentially change the leadership development industry, making many of the contemporary investments in leadership development obsolete.

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    Appendix 6 Key theoretical definitions in brief
  • Public defence: 2020-06-12 16:00 Seminar Room, Floor 5, Stockholm
    Gomez-Torrent, Adrian
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Submillimeter-Wave Waveguide Frontends by Silicon-on-Insulator Micromachining2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents novel radiofrequency (RF) frontend components in the submillimeter-wave (sub-mmW) range implemented by silicon micromachining, or deep reactive ion etching (DRIE). DRIE is rapidly becoming a driving technology for the fabrication of waveguide components and systems when approaching the terahertz (THz) frequency range. The conventional method to manufacture microwave waveguide components, CNC-milling, shows important limitations when used at sub-mmW frequencies or above, due to the reduced size of the waveguides. At the same time, the classic electromagnetic designs, oriented to CNC-milling, are often not suitable for their fabrication using alternative technologies. The work in this thesis aims to develop fabrication-oriented electromagnetic structures, making use of the full flexibility of silicon on insulator (SOI) micromachining, and enabling the implementation of complex RF frontends at a low fabrication complexity.

    The first part of the thesis reports on a turnstile orthomode transducer (OMT) in the WM-864 band (220 – 330 GHz). OMTs are key components in the feed-chain for radio astronomy, communications, or radiometry applications. However, their complex geometry has often limited their use when approaching the THz range, where polarization diversity is commonly avoided, or optical systems are preferred.

    The second part reports on a high-gain and broadband waveguide corporatefed array antenna in the WM-570 band (330 – 500 GHz). High gain and broadband antennas are required for the future generation of THz wireless communications. Reflector and lens antennas can meet these specifications, but their fabrication for the THz range requires precision machining, resultingin a high cost, low yield, and small scale production. The use of silicon micromachined antenna arrays overcomes these issues while providing a more compact frontend.

    In the third part of the thesis, a parallel plate waveguide (PPW) leaky wave antenna (LWA) fed by a quasi-optical beamforming network (BFN) in the WM-864 band is presented. The antenna frontend generates a pencil shaped beam scanning in elevation. The compact design, large bandwidth, and beam steering capabilities make this antenna a suitable frontend for THz radar applications.

    The final part of this thesis reports on a novel waveguide single pole double throw (SPDT) switch in the WM-570 band. The switch is demonstrated in a two-port network configuration with two switching states (ON/LOAD), used for receiver calibration, or for avoiding backward waves in transmitter switching. A more complex 1×4 switching matrix is also designed for the implementation of an active radar antenna operating at 340 GHz.

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  • Public defence: 2020-06-10 10:00 N/A (Via videolink due to Corona virus)
    Tomasson, Egill
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electric Power and Energy Systems.
    Impact of High Levels of Variable Renewable Energy on Power System Generation Adequacy: Methods for analyzing and ensuring the generation adequacy of modern, multi-area power systems2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The generation adequacy of electricity supply has been an ongoing concern since the restructuring of the industry. Ensuring generation adequacy was a rather straightforward task in the era of natural monopolies. Whose responsibility was it to ensure generation adequacy as the industry became deregulated and more fragmented? Who is willing to finance rarely used generating units? After decades of experience with the competitive electricity market, the question of whether market forces alone are sufficient to ensure generation adequacy still remains.

    Recent energy policies have moreover set a goal of a high share of renewable energy in electricity markets. The presence of high levels of renewable generation makes the supply side of the market more uncertain. This volatility in energy production induces volatility in energy prices which means that the revenue stream of conventional generating technologies is more uncertain than it has traditionally been. This can even deteriorate the economics of some generators to the point where they exit the electricity market. The installed capacity of dispatchable generation can therefore be reduced.

    These developments bring up the question of whether the generation adequacy of modern and future, deregulated and highly variable power systems is ensured. This dissertation focuses on modeling the generation adequacy of modern power systems with a high penetration of variable renewable energy sources. Moreover, the dissertation looks at some solutions with the aim of ensuring the generation adequacy of such systems through various means such as coordinated reserves, energy storage as well as utilizing the flexibility of the demand side of the market.

    The models developed in this dissertation are verified using well-known test systems as well as through large-scale analysis of real-world systems. Aside from focusing on the simulation of power systems, the developed models moreover focus on achieving high computational efficiency. This is done through means such as advanced Monte Carlo simulation and optimization methods that apply decomposition to speed up the simulations.

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  • Public defence: 2020-06-12 10:00 Stockholm
    Bergendal, Erik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Fatty Acid Self-Assembly at the Air–Water Interface: Curvature, Patterning, and Biomimetics: A Study by Neutron Reflectometry and Atomic Force Microscopy2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    For more than a hundred years of interfacial science, long chain fatty acids have been the primary system for the study of floating monolayers at the air–water interface due to their amphiphilic nature and system simplicity: an insoluble hydrocarbon chain and a soluble carboxyl group at a flat air–water interface. Despite―or perhaps rather due to―the assumed simplicity of such systems and the maturity of the research field, the seemingly fundamentally rooted notion of a two-dimensional water surface has yet to be challenged.

    The naturally occurring methyl-branched long chain fatty acid 18-methyleicosanoic acid and one of its isomers form monolayers consisting of monodisperse domains of tens of nanometres, varying in size with the placement of the methyl branch. The ability of domain-forming monolayers to three-dimensionally texture the air–water interface is investigated as a result of hydrocarbon packing constraints owing to the methyl branch.

    In this work, neutron reflectometry has been used to study monolayers of branched long chain fatty acids directly at the air–water interface, which allowed precise probing of how a deformable water surface is affected by monolayer structure. Such films were also transferred by Langmuir–Blodgett deposition to the air–solid interface, and subsequently imaged by atomic force microscopy. Combined, the results unanimously―and all but unambiguously―show that the self-assembly of branched long chain fatty acids texture the air–water interface, inducing domain formation by a local curvature of the water surface, and thus controverting the preconceived notion of a planar air–water interface. The size and shape of the observed domains are shown to be tuneable using three different parameters: in mixed systems of branched and unbranched fatty acids, with varying hydrocarbon length of the straight chain, and altering subphase electrolyte properties. Each of these factors effectively allows changing the local curvature of the monolayer, much like analogous three-dimensional systems in bulk lyotropic crystals. This precise tuneability opens up for sustainable nanopatterning. Finally, the results lead to a plausible hypothesis of self-healing properties as to why the surface of hair and wool have a significant proportion of branched fatty acid.

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    (fulltext) Fatty Acid Self-Assembly at the Air–Water Interface
  • Li, Yuanyuan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Fu, Qiliang
    Rojas, Ramiro
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Yan, Min
    KTH, School of Electrical Engineering (EES).
    Lawoko, Martin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Lignin-Retaining Transparent Wood2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 17, p. 3445-3451Article in journal (Refereed)
    Abstract [en]

    Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light-transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30wt% of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Moreover, lignin removal weakens the wood structure, limiting the fabrication of large structures. A green and industrially feasible method has now been developed to prepare transparent wood. Up to 80wt% of lignin is preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high-lignin-content transparent wood with transmittance of 83%, haze of 75%, thermal conductivity of 0.23WmK(-1), and work-tofracture of 1.2MJm(-3) (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained shows potential for application in energy-saving buildings.

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  • Quino Lima, Israel
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering. KTH Royal Institute of Technology.
    Ormachea Muñoz, Mauricio
    Universidad Mayor de San Andrés.
    Ramos Ramos, Oswaldo Eduardo
    Universidad Mayor de San Andrés.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Geochemistry and Ecotechnology. KTH, Superseded Departments (pre-2005), Civil and Environmental Engineering. KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Quispe Choque, Raul
    Universidad Mayor de San Andrés.
    Quintanilla Aguirre, Jorge
    Universidad Mayor de San Andrés.
    Sracek, Ondra
    Palacky´ University.
    Hydrochemical assessment with respect to arsenic and other trace elementsin the Lower Katari Basin, Bolivian Altiplano2019In: Groundwater for Sustainable Development, p. 281-293Article in journal (Other academic)
    Abstract [en]

    Hydrochemical investigations of groundwater and surface water were carried out to better understand the spatial distribution of As, major ions and trace elements.The study was carried out to evaluate the sources of dissolved species and elucidate the processes that govern the evolution of natural water in the Lower Katari Basin.The study area is close to the Titicaca Lake (Cohana Bay) formed by sediments of the Quaternary system, deposited in the fluvio-glacial to fluvio-lacustrineenvironment and geologic formations of the Devonian and Neogene system of volcanic origin. The study area has several environmental problems mainly caused bycontaminants such as heavy metals, nutrients, and bacteria. These problems are linked to the urban and industrial wastes, natural geologic conditions, and miningactivities carried out upstream of the Katari Basin, where rivers discharge into the Cohana Bay.A total of 37 water samples were collected during wet season, 31 groundwater samples including drinking water wells and six surface water samples. Thehierarchical cluster analysis and principal component analysis were applied to hydrochemical data. Results show high salinity in groundwater related to theevaporation causing serious problems for the groundwater quality and rendering it unsuitable for drinking. Dissolved As concentration ranges from 0.7 to 89.7 μg/L;the principal source of As could be the alteration of volcanic rocks, more than 48% of the shallow groundwater samples exceeded the WHO guideline value for As andmore than 22% for NO3-. Groundwater has neutral to slightly alkaline pH, and moderately oxidizing character. The groundwater chemistry reveals considerablevariability, ranging from Na-SO4,Cl type through mixed Na-HCO3 type and Ca,Na-HCO3,Cl type. The distribution of trace elements shows a large range of concentrations.Speciation of As indicates that the predominant oxidation state is As (V). The geochemical modelling indicates that As could be associated with ironoxides and hydroxides which are probably the most important mineral phases for the As adsorption. The spatial distribution and the variation of dissolved Asconcentration in groundwater is governed by the variability in geological characteristics of the region that raises a significant concern about drinking water quality.

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  • Public defence: 2020-06-04 15:00 https://kth-se.zoom.us/j/67302879470, Stockholm
    Zhang, Liang
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology. AdBIOPRO, VINNOVA Competence Centre for Advanced Bioproduction by Continuous Processing.
    Development of mathematical modelling for the glycosylation of IgG in CHO cell cultures2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Chinese hamster ovary (CHO) cells are the most popular expression system for the production of biopharmaceuticals. More than 80% of the approved monoclonal antibodies (mAbs) or immunoglobulin G (IgG) are produced with these cells. Glycosylation is a usual post- translational modification important for therapeutic mAbs. It affects their stability, half-life and immunological activities. Substantial studies have shown that glycosylation can be affected by the culture conditions in manufacturing, e.g. pH, temperature and media components. To achieve a good control of the glycosylation, a number of mathematical models have been developed. However, most of them have been developed for the cell line engineering, while very few can be used to design the media components for matching a given glycoprofile.

    This thesis presents developments of mathematical modelling for glycosylation prediction and experimental design of feeding different combinations of carbon sources in CHO cell cultures. The first study investigates the impacts of mannose, galactose, fructose and fucose to the IgG glycoprofile. Specifically, we look at intracellular nucleotide sugars in fed-batch cultures, where glucose is absent and lactate is used as complementary carbon source. The second study is based on the concept of elementary flux mode (EFM) and the mass balance of the glycan residues. A mathematical model named Glycan Residue Balance Analysis (GReBA) is developed for the prediction of the glycosylation profiles of IgG in pseudo perfusion cultures by feeding combinations of glucose, mannose, galactose and lactate. The model is further optimized for a feeding strategy design of perfusion cell cultures to obtain a desired glycoprofile. In the last study, a probabilistic graphic model based on Bayesian network (BN) is developed for glycosylation prediction in cultures under different multiple variable factors affecting the glycosylation.

    The results show that the manipulation of different sugars in the media can be used to control the glycosylation. Both the GReBA and PGM models exhibit abilities for glycosylation prediction and experimental design.

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  • Li, Junhao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Li, Weihua (Contributor)
    East China University of Science and Technology.
    Tu, Yaoquan (Contributor)
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Mechanistic Insights into the Regio‐ and Stereoselectivities of Testosterone and Dihydrotestosterone Hydroxylation Catalyzed by CYP3A4 and CYP19A12020In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 26, p. 6214-6223Article in journal (Refereed)
    Abstract [en]

    The hydroxylation of nonreactive C−H bonds can be easily catalyzed by a variety of metalloenzymes, especially cytochrome P450s (P450s). The mechanism of P450 mediated hydroxylation has been intensively studied, both experimentally and theoretically. However, understanding the regio‐ and stereoselectivities of substrates hydroxylated by P450s remains a great challenge. Herein, we use a multi‐scale modeling approach to investigate the selectivity of testosterone (TES) and dihydrotestosterone (DHT) hydroxylation catalyzed by two important P450s, CYP3A4 and CYP19A1. For CYP3A4, two distinct binding modes for TES/DHT were predicted by dockings and molecular dynamics simulations, in which the experimentally identified sites of metabolism of TES/DHT can access to the catalytic center. The regio‐ and stereoselectivities of TES/DHT hydroxylation were further evaluated by quantum mechanical and ONIOM calculations. For CYP19A1, we found that sites 1β, 2β and 19 can access the catalytic center, with the intrinsic reactivity 2β>1β>19. However, our ONIOM calculations indicate that the hydroxylation is favored at site 19 for both TES and DHT, which is consistent with the experiments and reflects the importance of the catalytic environment in determining the selectivity. Our study unravels the mechanism underlying the selectivity of TES/DHT hydroxylation mediated by CYP3A4 and CYP19A1 and is helpful for understanding the selectivity of other substrates that are hydroxylated by P450s.

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  • Public defence: 2020-06-05 10:00 Publikt via ZOOM, Stockholm
    Ternstedt, Patrik
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    A Study of Parameters that Influence the Kinetics of the AOD Decarburisation Process2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis focuses on the AOD process, which is an important metallurgical reactor in stainless steel production. To be more specific, the thesis is limited to study the decarburisation step, which is the first of three process steps in the AOD converter. The main research questions is to increase the knowledge of reasons for random differences in decarburisation rates during the process. In the first part of the study, physical modeling is used to study the mixing in AOD converters. Parameters that were studied included, bath heights, gas flow rates and chemical reactions. The results showed that the mixing time decreased with an increased gas flow rate or an increased bath height. In addition, the influence of the top slag on the fluid flow and mixing time was studied. The results showed that the flow field was influenced by the slag phase and that it is of importance to account for the solid slag fractions to simulate the fluid flow and mixing time to resemble AOD converters. However, the results from this first part of the thesis illustrates that mixing is not the rate-limiting step for decarburisation in AOD converters. Instead, the focus was shifted to study if the slag was the cause for random differences in the decarburistaion rate. Slag samples were collected from an industrial AOD reactor. These slags are quite unique since they contain mainly solids and a small liquid fraction. Thus, petrography was used to study the samples and a new methodology was developed to characterize the slag samples. Methods for characterising the top slag samples from the AOD process were established, including combinations of different techniques. The common slag phases in decarburisation slag were identified. The results showed good agreement with samples analysed with SEM and EDS compared to calulations made in Thermo-Calc. Overall, it was shown that the slag characteristics changes during the decarburization period and that these changes can be determined using the new methodology. In the last part of the thesis, the commercial AOD process control model TimeAOD2 was used in combination with Thermo-Calc calculations to study how the process could be improved so that the slag composition became most beneficial for improving the kinetics of the decarburisation part of the AOD converter process. The results show that it is possible to predict the slag composition and especially the amount of liquid slag in the sample. This in turn, makes it possible to better estimate the optimal lime addition depending on the silicon content in steel and the amount of carry-over slag from the electric arc furnace.  Furthermore, it is shown that to large lime additions will lead to an increased heating time while not improving the decarburization rate.

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  • Public defence: 2020-06-08 13:30 Publikt via Zoom, Stockholm
    Taibi, Emanuele
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    A multi-sector framework for accelerating renewable energy deployment in power, transport and industry2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Climate change is the defining issue of our time (United Nations, 2018). Renewable energy, combinedwith energy efficiency, can potentially be the most effective solution to address energy-relatedGreenhouse Gas (GHG) emissions. This work covers global, regional and national strategies to acceleratedeployment of renewable energy in power, transport and industry, using a variety of methodologies toaddress sectoral challenges and account for sectoral specificities. These sectors jointly represented 85%of energy-related emissions in 2016 (IRENA, 2019a).The thesis is structured around four focus areas. Foci 1-3 investigate the key components of an energytransformation jigsaw that looks at key sectors in which renewable energy can be integrated: industry,transport and power. The fourth focus area is informed by the other three and provides key insights forthe necessary institutional setting and changes for the transition to renewable energy to play out.Focus 1: Decarbonising industryIndustry needs a combination of electricity and heat, therefore apart from decarbonising electricity it isalso necessary to decarbonise heat: depending on temperature levels, a combination of solar thermal,heat pumps and most prominently bioenergy can help in decarbonising process heat. In this thesis I focuson the often overlook role of renewable energy in process heat provision. The analysis presented here isglobal in scale and covers all manufacturing sectors, assessing the potential for biomass, as well as solarthermal and heat pumps, to provide the necessary process heat for industry. This, in combination withincreased electrification and the production of hydrogen from renewable power, charts the way in termsof decarbonisation of industry at the global level. Results show that renewables can replace 50% of fossilfuel consumption for industry. In addition to this, decarbonisation of electricity supply can indirectlydecarbonise industry, especially if industrial energy demand is further electrified.Focus 2: Decarbonising transportIn the transport sector, we can replace petroleum fuels with renewable fuels. To date, this has beenachieved mostly with biofuels. In the future, renewables-based hydrogen and its derivatives can also bea significant source of carbon-neutral fuels. Finally, we are witnessing the rise of battery electric vehicles,which can be leveraged to provide flexibility to the power system and integrate more solar and wind,creating a virtuous cycle of more renewables in power and in transport at once. The analysis presentedin this thesis covers both the structural evolution of the automotive sector in Europe, and how the shiftfrom gasoline to diesel in passenger cars would affect the demand for biodiesel as opposed to ethanol,and the impact of battery electric vehicles (EVs) on the power system. In particular, this analysis looks athow EVs can be leveraged to facilitate the integration of large shares of solar and wind into powersystems, with an application to a small island developing state (SIDS) that pledge to go 100% renewableenergy by 2030, Barbados. Sectoral interactions, like the impact of electric vehicles on the power sector,are also crucial in determining a smooth, coordinated transition of the energy sector away from fossilfuels, further improving affordability and reliability of energy services.Focus 3: Transforming the power sector through rapid deployment of solar and windAs the power sector is a fundamental driver for the energy transition, this PhD tackles some of thechallenges related to the use of solar and wind as main sources for power sector decarbonisation. This 

    PhD covers methodological aspects on how to perform the necessary planning studies to transform thepower system using solar and wind generation. This methodological planning framework is applied 1) inthe power generation expansion plan for the Republic of Cyprus, as a key contribution to the developmenton the National Energy Roadmap of Cyprus, 2) to the Pacific Small Island Developing State (SIDS) of Samoa,looking at how different studies can translate policy targets into a renewable-based, reliable andaffordable power system, and 3) to the Caribbean SIDS of Barbados, where the power system analysisshows how to link the power sector to the transportation sector to provide mutual benefits from thedecarbonisation of both sectors.Focus 4: The institutional framework for accelerated renewable energy deploymentFor change to happen, especially at the pace and scale required to meet the objectives of the Parisagreement, the institutional framework for the energy sector requires changes. Increased electrificationaccompanied by decarbonisation of the power sector requires significant changes to how electricity isprocured, regulated, traded and financed. In some regions policies and markets should be adjusted orredesigned. In other regions, the absence of unbundled wholesale electricity markets could be initially achallenge but could be turned into an opportunity for an easier, speedier transition implemented by avertically integrated utility, which is the most common model to date in the majority of countries.Institutional frameworks are very specific for each country or, at best, region, and are difficult to transferfrom one context to another; however, they often remain the largest obstacle to an acceleration inrenewable energy deployment.Beyond the power sector, industry is a sector where change is difficult to achieve at speed, as largeinvestments already in place and global competitiveness of products and services make transitionsparticularly difficult. Additionally, industry requires rapid returns, limiting the spectrum of viableinvestments into new processes, which in turn limits energy efficiency potential and the possibility ofadopting renewable energy to replace fossil fuels.For renewables in transport, a precedent has been set by biofuels, as in many regions and countries theyrepresent an important renewable energy resource for decarbonisation of transport. Moving forward,especially for global sectors like shipping and aviation, a broader framework will be required to introducecarbon-neutral fuels at scale.Overall, the goal of this thesis is to provide policy makers with a set of tools and examples that can supportthe development of effective policies and plans for the increased adoption of renewable energy sourcesat the global, regional and national level and spanning transport, industry and the power sector.

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    Emanuele Taibi - PhD Thesis
  • Tillybs, Eric
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Quantified Evaluations of IT-Tools2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Scania CV is a premium truck, bus and engine manufacturer. At Scania there is a research and development department, in the thesis referred to as the R&D department, which delivers ITtool solutions for internal customers at Scania. After a new IT-tool has been implemented The R&D department want to be able to evaluate the benefits enabled by the IT-tool. Today the R&D department mainly identifies tangible benefits such as improved quality, saved time and saved money due to the use of a new IT-tool. The R&D department have expressed that they see room for improvement both in the phase of prioritizing between what IT-tool projects to start and in the evaluation of IT-tools. Scania often prioritize product development projects for external customers before IT-tool development projects for internal customers. The R&D department believes that the position of IT-tool projects for internal customer could be strengthen if a more comprehensive IT-tool evaluation could be implemented. This way a better case could be made to emphasize the importance of prioritizing new IT-tool projects for internal customers. The purpose of this master thesis is to create a tool to manage benefits and disbenefits of IT-tools by making the R&D department able to identify, categorize, rank and evaluate benefits and disbenefits enabled by IT-tools. The result of the thesis has been found through a literature study, multiple workshops, and semi structured interviews with employees linked to two different IT-tools A and –B together with validation in an improvement group linked to another IT-tool C. The result of the thesis is known as the IT-Tool Evaluator and consists of a list of benefit aspects with corresponding weights. Two surveys and a calculation template has been developed with the purpose to quantify how a new IT-tool fulfils these benefit aspects. One survey focus on the IT-tool user and one survey has a focus of a company perspective. The benefit aspects are visualised using radar diagrams, a score for each aspect is calculated and a total score for the IT-tool is generated. The difference in score in each of the 22 benefit aspects in the new IT-tool and the IT-tool that is being replaced decides if the new IT-tool brings a positive change (benefit) or negative change (disbenefit) in the given aspect.

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  • Gomez-Torrent, Adrian
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Tomura, Takashi
    Kuramoto,, Wataru
    Hirokawa, Jiro
    Watanabe, Issei
    Kasamatsu, Akifumi
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    A 38 dBi Gain, Low-Loss, Flat Array Antenna for 320 GHz to 400 GHz Enabled by Silicon-On-Insulator Micromachining2020In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 68Article in journal (Refereed)
    Abstract [en]

    Two high-gain flat array antenna designs operatingin the 320 – 400 GHz frequency range are reported in this paper. The two antennas show measured gains of 32.8 dBi and 38 dBi and consist of a 16x16 (256) element array and a 32x32 (1024) element array, respectively, which are fed by a corporate H-tree beamforming network. The measured operation bandwidth for both antennas is 80 GHz (22% fractional bandwidth), and the total measured efficiency is above −2.5 dB and above −3.5 dB forthe two designs in the whole bandwidth. The low measured loss and large bandwidth are enabled by optimizing the designs to the process requirements of the SOI micromachining technology used in this work. The total height of the antennas is 1.1mm (1.2 at the center frequency), with sizes of 15mm x 18mm and 27mm x 30mm for both arrays. The antennas are designed to be directly mounted onto a standard WM-570 waveguide flange.The design, fabrication, and measurements of eight prototypes are discussed in this paper and the performance of the antennas compared to the simulated data, as well as manufacturability and fabrication repeatability are reported in detail.

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  • Public defence: 2020-06-05 13:00 Publikt via Zoom, Stockholm
    Fagrell, Per
    KTH, School of Industrial Engineering and Management (ITM), Learning.
    Change and inertia in the development of Swedish engineering education: The industrial stakeholder perspective2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis investigates higher education development in Sweden from an external stakeholder perspective, with a particular focus on engineering education. Industry has long been a major external stakeholder in the development of profession-oriented higher education, not least in the context of engineering education. Representatives of industry and other employers have continuously called for developments in the curriculum to prepare students for an evolving profession. Scholars of higher education have gone so far as to depict employers as the definitive stakeholder in higher education today. However, it has also been claimed that engineering education and its institutions are, and always have been, rather unresponsive to external calls for changes. These partly contrasting views call for a study of the role of industry vis-à-vis the different strategies that higher education institutions can draw upon to respond to external calls for change. Thus, the following overarching research question is posed: What kind of role does an external stakeholder such as industry have in the development of engineering education?

    The conceptual framework for the thesis is based on literature on organisational continuity and change, response strategies to external calls for change, university–business collaboration, and curriculum development and quality. The main theoretical concept presented in the thesis, however, is stakeholder theory and stakeholder analysis. A model for stakeholder analysis is chosen and presented in which the assessment of the attributes power, legitimacy and urgency form the basis for the analysis of the stakeholders’ salience.

    Empirically, the thesis is based on three studies, which have yielded four appended papers. The studies represent different situations in which external stakeholders have had the possibility of impacting higher education. All three studies have an interpretative and qualitative methodological approach, with semi-structured interviews as the main source for data collection, combined in the second study with historical document studies. In order to frame these studies in their historical context, an overview of the development of engineering education in Sweden is presented as a background. In this overview, the development of relationships between industry and engineering education institutions are depicted with reference to a series of milestone events.

    The results show that, from a historical perspective, industry has indeed been an influential stakeholder to engineering education. It is argued that while industry still is an important stakeholder, higher education institutions today have to attend to the interests of a broader range of stakeholders, including students, government and others. Claims in the international literature that employers are the definitive stakeholder in higher education does not seem to fit well with the Swedish context, as analysed in this thesis. This may be partly understood as a consequence of a shift away from national-level decision-making regarding higher education development, leaving previous structures for active stakeholder influence less potent.

    Important decisions about engineering education have in Sweden moved from a national and centralised level to an international level, exemplified by the Bologna Process and the global quality assurance and enhancement scheme called the CDIO[1] Initiative, and at the same time to a local level due to an ambitious autonomy scheme for higher education institutions in Sweden. This can be seen as a divergent trend compared to an international setting, specifically in Anglophone countries where the Washington Accord acts as the basis for curriculum development. This accreditation agreement is heavily influenced by the accreditation scheme for engineering education in the United States, the ABET criteria, in whose formulation employer representatives have a major impact. It may be questioned whether industry representatives have fully recognised this shift in the decision-making process in the engineering curriculum in Sweden. With regard to earlier claims that engineering education and its institutions are unresponsive to external calls for change, the thesis concludes that higher education institutions respond and act, but not always in the way external stakeholders expect or want. External stakeholders have to persist in their eternal quest for progress and development in engineering education, but they may have to adjust and divert their attention to both an international and local context at the same time.

    [1] CDIO: Conceive-Design-Implement-Operate

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  • Public defence: 2020-06-08 13:00 Via Zoom: https://kth-se.zoom.us/webinar/register/WN_8vcAAGzGR0KapHqV6MlWyQ, Stockholm, Sweden
    Ddiba, Daniel
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Sustainability Assessment and Management. Stockholm Environment Institute (SEI).
    Exploring the circular economy of urban organic waste in sub-Saharan Africa: opportunities and challenges2020Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Globally, there is increasing awareness of the importance of applying circular economy principles to the management of organic waste streams through resource recovery. In the urban areas of sub-Saharan Africa which are going to host a significant part of population growth over the next three decades, this is especially relevant. Circular economy approaches for sanitation and waste management can provide incentives to improve infrastructure and consequently contribute resources for water, energy and food that power urban livelihoods. This thesis is situated at the intersection of the circular economy on one hand and sanitation and waste management systems on the other. It aims to contribute to knowledge about the circular economy by investigating the potential contribution of resource-oriented urban sanitation and waste management towards the implementation of a circular economy in sub-Saharan Africa and the opportunities and challenges thereof.

    In pursuit of the above aim, the thesis employs a mixed methods approach and is operationalized in two case study locations: Kampala (Uganda) and Naivasha (Kenya). The findings reveal the quantities of resource recovery products like biogas, compost and black soldier fly larvae that can be obtained from the organic waste streams collected in a large city, demonstrate the viability of valorizing dried faecal sludge as a solid fuel for industrial applications, and identify the factors that facilitate or impede the governance capacity to implement circular economy approaches to the management of organic waste streams in urban areas in sub-Saharan Africa. The methods used for quantifying the potential for valorizing organic waste streams and for assessing governance capacity demonstrate approaches that could be applied in other urban contexts with interest in implementing circular economy principles. The discussion highlights some key implications of these findings for sanitation and waste management practices, arguing that it is time for a shift in sub-Saharan Africa from designing sanitation and waste management systems for disposal to designing them for resource recovery.

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    Ddiba_LicentiateKappa_2020
  • Pustan, Daniel
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Government favoritism in public procurement: Evidence from Romania2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In Romania, the consideration that politicians use their influence to control the public procurement market is axiomatic. It is no surprise that the country ranks high in perceptionbased surveys or the low participation of firms on the procurement market. The more difficult task is to demonstrate the existence of restrictions to procurement contracts in order to benefit preferred companies. That is, to measure the extent to which the market is captured by favored companies. Employing data on all public procurement contracts in Romania for the period 2009 – 2015, this paper examines government favoritism in public procurement exerted by political parties. Using a dynamic panel data approach (Dávid-Barrett and Fazekas 2019), the companies are classified based on their winning pattern with respect to government change. Favoritism is observed if winning companies within the government period are also associated with a higher risk of corruption measured by two alternative approaches. The findings confirm that procurement market is captured in a low to moderate proportion (24%) and that the market display patterns of systematic favoritism. This may signal certain progress registered by Romania to combat political corruption. Arguably, the insensitivity of perception indicators with respect to this progress is, at least partly, due to media coverage of the on-going corruption investigations related to the past.

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  • Mutter, Patrick
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Kores, Cristine C.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Laurell, Fredrik
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics. KTH, School of Engineering Sciences (SCI), Physics. KTH, Superseded Departments (pre-2005), Physics.
    Canalias, Carlota
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics. KTH, Superseded Departments (pre-2005), Materials Science and Engineering. KTH, School of Engineering Sciences (SCI), Physics. KTH, Superseded Departments (pre-2005), Physics.
    Ionexchanged Waveguides in Periodically PoledRb doped KTiOPO 4 for Efficient Second HarmonicGeneration2020Conference paper (Refereed)
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  • Koch, Daniel
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Architecture, Urban Design.
    Legeby, Ann
    KTH, School of Architecture and the Built Environment (ABE), Architecture, Urban Design.
    Preliminär rapport: Vår Stad - hur förändrar en kris våra vanor?2020Report (Other (popular science, discussion, etc.))
    Abstract [sv]

    Under Coronapandemin införs omfattande restriktioner och många åtgärder sätts in i syfte att förhindra smittspridning av Covid-19. Myndigheter, företag och organisationer introducerar en lång rad förändringar såsom distansarbete, distansundervisning, uppmaning om att endast göra nödvändiga resor med kollektivtrafiken men också att praktisera social distansering och självisolering. Det har resulterat i en extraordinär situation i samhället där många företag över en natt förlorat intäkter och där andra verksamheter upplever en ökad belastning, till exempel inom vården. Att begränsa rörelsemöjligheterna för så många har lett till att människor i högre utsträckning blir beroende av det som finns lokalt, blir hänvisade till det utbud och de möjligheter som erbjuds i grannskapet och i stadsdelen. Krisen har på många sätt accentuerat ojämlikheter och där människor med mindre resurser riskerar att bli utsatta och fara illa i högre utsträckning än andra. 

    För att fånga de förändringar som vi genomlever i samhället till följd av pandemin så har en webbaserad kartenkät tagits fram där människor tillfrågas om hur deras vanor ändrats i fråga om hur staden används. Vi vill öka förståelsen för vilka platser som människor fortfarande besöker, vilka man undviker och om det eventuellt finns platser som används i högre utsträckning än tidigare. Vidare önskar vi lära oss mer om varför dessa platser besöks. Under krisen har diverse undersökningar visats som utifrån t.ex. smarta telefoner, appar eller liknande kartlägger aktiviteter och användning av platser. Syftet med web-enkäten Vår Stad är att få självrapporterade svar där det också finns mer information om vad som händer på dessa platser och varför man använder eller undviker en specifik plats. 

    De preliminära svaren omfattar svar från en månad (25/3-27/4 2020) där Stockholm, Uppsala och Göteborg framför allt ingår.

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    Vår Stad - Preliminär rapport
  • Public defence: 2020-06-04 10:00 Registrera dig här: https://kth-se.zoom.us/webinar/register/WN_Bp8dzpcbQMKNNOGyj51R2g, Stockholm
    Sjölander, Andreas
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Structural behaviour of shotcrete in hard rock tunnels2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Tunnels in hard and jointed rock are normally excavated in an arch shape to enable the rock mass to support its weight. Since the beginning of the 1980's, fibre reinforced shotcrete (FRS) in combination with rock bolts have been the dominating support method for hard rock tunnels. This type of rock support is a complex composite structure in which the structural behaviour depends on interaction between shotcrete, rock and bolts. The design is commonly based on a rock mass classification system in combination with analytical solutions or finite element (FE) modelling. However, the in-situ variations of important properties of the shotcrete are normally neglected.

    The aim of this thesis is to describe and explain how the variations in shotcrete thickness and bond strength affect the structural behaviour and capacity for a shotcrete lining. Especially, the influence of local variations in shotcrete thickness and bond strength has been studied in detail. For this purpose, a numerical framework capable of simulating bond failure, cracking of FRS and pull-out failure of grouted rock bolts have been developed. Moreover, in-situ data for shotcrete thickness and bond strength have been collected and analysed to characterize  the variations in important shotcrete parameters.

    The results in this thesis show that when shotcrete is subjected to shrinkage, local variations in shotcrete thickness affects the crack pattern. However, the number and width of the cracks are similar to the case with uniform thickness. Most importantly, a pattern of fine and narrow cracks develops in unreinforced shotcrete subjected to shrinkage when a continuous bond to the rock exists. When shotcrete is subjected to the load from a loose block, the force is transferred to the surrounding rock through bond stresses distributed over a narrow band. Simulations have shown that the structural capacity, with respect to bond failure, depends on the shotcrete thickness. Moreover, a strong linear correlation was found between the mean value of the bond strength and shotcrete thickness around the perimeter of the block and the structural capacity. Local weak areas, i.e. with low bond strength or thickness, may exist around the perimeter without having a significant effect on the structural capacity. Design of bolt-anchored shotcrete linings is based on failure modes previously derived from experimental testing. This thesis has contributed to an increased understanding of the failure mechanisms of the lining and has confirmed that the design can be based on individual failure mechanisms.

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  • Taibi, Emanuele
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    A system dynamics energy model for a sustainable transportation system2010In: Proceedings of the 28th International Conference of the System Dynamics Society: July 25 – 29, 2010. Seoul, Korea, Boston, USA, 2010Conference paper (Refereed)
    Abstract [en]

    The transportation sector is one of the most resilient to the shift away from oil. Policies have been put in place in different regions to introduce alternative fuels and reduce the road transportation heavy dependency on oil products and the related environmental impacts; results, however, are in most cases disappointing. The system is resilient and goes back to the historical dichotomy gasoline-diesel. If from a policy maker perspective, a system dynamics model of the automotive sector can lead to the development of effective policies to achieve sustainable mobility, from an energy company perspective, such a model could be used to analyze possible threats and design optimal adaptation strategies for a highly volatile and market that is always on the edge of starting a new major transition. The model here presented can serve both purposes, and the results obtained show how a similar instrument can really make the difference in highly dynamic sectors with ongoing major transitions.

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  • Fagrell, Per
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Learning.
    Geschwind, Lars
    KTH, School of Education and Communication in Engineering Science (ECE), Learning, Organisation and leadership. KTH, School of Industrial Engineering and Management (ITM), Learning.
    A stakeholder analysis of an educational policy reform: The transition from Technical College Graduate to Bachelor of Science in Engineering in SwedenManuscript (preprint) (Other academic)
    Abstract [en]

    In the early 1990s, the lower engineering degree in Sweden was transformed into a two-year engineering degree at the higher education level. This profound educational policy reform was preceded by more than ten years of investigations and preparations, with contributions from various stakeholders. With this policy reform, Sweden took its place alongside many other countries that had already implemented similar reforms to elevate what had traditionally been their more practically oriented engineering education. By using an oral history approach, i.e., a combination of historical text studies and interviews, this study explores the events leading up to the decision to enact this educational transformation. The focus is on the stakeholders involved and the roles they played. A division of the decision-making process into three phases shows how different stakeholders were more active in different phases. We conclude that it is not possible to identify any single stakeholder as more important than the others in this decision-making process, nor is there a single argument or single event that is decisive. Different proposals were tested and scrutinized, and by being an active part in the discussion, a final proposal with broad support from many stakeholders eventually emerged.

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  • Uhlin, Amanda
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Hajek, Isabelle
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Assessment of the water storage potential at Lake Mjölhatteträsk on Storsudret, Gotland2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    During the recent summers, Gotland has suffered from drinking water shortage and due to the climate change, the water shortage can possible increase in the future. To find a solution, the Swedish Environmental Research Institute IVL and Region Gotland are going to build a testbed at Storsudret located on the south of Gotland, to investigate different sustainable solutions. One possible solution is to increase the water level in Lake Mjölhatteträsk, located at Storsudret, to increase the water storage. This master thesis has focused on the water balance of the lake to understand whether it is possible to store more water in the lake and how large areas that would be flooded in the event of an increase in the water level. This has been done using a combination of field data sampling with geophysical methods, hydraulic tests, water depth measurements, existing hydrometeorological data from Lantmäteriet and the Geological Survey of Sweden (SGU) and modelling with the tools MIKE SHE and MIKE HYDRO River created by DHI and also GIS.

    The result of this master thesis showed that there is a very thin soil layer with possibly high clay and silt content to the west of the lake. At the bottom of the lake, a thick clay layer exists which reduces the hydraulic connection between the lake and the surroundings. The potential to store and extract water in the sand layer in the west is therefore small. However, there is potential to produce enough water in the lake to meet the water demand at Storsudret, according to the model created in MIKE SHE. This would require a dam at a suggested location at the outflow with a height of 0.12 m.

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  • Public defence: 2020-06-10 10:00 publikt via ZOOM, Stockholm
    Han, Tong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Catalytic pyrolysis of lignin to produce fuels and functional carbon materials 2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Development of renewable energy carriers and green adsorbents is an essential step in creating a fossil-free and toxin-free future of the world. Lignin is the second highest component of biomass and the only renewable resource of aromatics in nature. Currently, around 70 million tons of lignin are produced annually from the pulp and paper industries word-wide, while only 1-2% of them can be upgraded into value-added products. Pyrolysis is one of the most promising technologies for lignin conversion to produce value-added products. After a lignin pyrolysis process, biooil, biogas, and biochar can be produced. Wherein, after upgrading, biogas and biooil can be used as alternatives to fossil based energy carries to produce fuels or chemicals; biochar can be used as carbon source to produce green adsorbents for pollutants removal. 

    This dissertation provides a systematic research focusing on the catalytic pyrolysis of lignin to produce upgraded biofuels and magnetic activated carbons (MACs). First of all, two specific issues i.e. sulfur and melting unique to lignin pyrolysis process are studied to achieve a thorough understanding of the lignin pyrolysis processes. Investigation of sulfur evolution during the lignin pyrolysis process is the study carried out first. Understanding lignin melting characteristics is the study carried out subsequently. Hereafter, in situ catalytic pyrolysis of lignin over low-cost catalysts is studied to produce upgraded biooils. Low-cost catalysts with different textural and acidic properties screening is the study carried out first. Development of a self-sufficient catalytic pyrolysis of lignin process via using activated carbons (ACs) derived from the same lignin pyrolysis process as catalysts is the study carried out subsequently. At last, pyrolysis and subsequent steam gasification of metal dry impregnated lignin is studied to produce MACs and H2-rich syngas. Development of a streamlined process to produce high-quality MACs for phosphorous adsorption is the study carried out first. Pyrolysis and subsequent steam gasification of metal dry impregnated lignin to co-produce MACs and H2-rich syngas is the study carried out subsequently.

    The study of sulfur evolution during the lignin pyrolysis process implies that sulfur-containing radicals are more likely to combine with other small radicals during a fast pyrolysis process. As a result, the main detected sulfur-containing compounds are small molecular gases or liquids with low boiling points and the main compounds in liquid phase are sulfur-free. The study of lignin melting characteristics at pre-pyrolysis temperature implies that the degree of cross-linked of the lignin structure determines its melting characteristics. Lignin extracted from pulping process has a less cross-linked structure. Therefore, it melts and softens to a flow state after a glass transition. Lignin extracted from hydrolysis process has a more cross-linked structure. Therefore, it does not melt but rather decompose after a glass transition.

    The study of low-cost catalysts with different acidic and textural properties screening for in situ catalytic pyrolysis of lignin implies that the use of only commercial AC as a catalyst induces the enhanced yield of monocyclic aromatic hydrocarbons (MAHs) among all low-cost catalysts. Bentonite and red mud catalysts have strong surface acidity but poor porous properties. This determines that produced reactive intermediates are easy to repolymerize to form char or coke without the blocking effect of pore wall. Commercial AC has an abundant porous structure as well as a surface acidity with a certain strength. The produced reactive intermediates could be isolated by pore walls and therefore induce the of MAHs production. A subsequent study of in situ catalytic pyrolysis of lignin over ACs from the same lignin pyrolysis process implies that the use of only AC that has more mesopores than micropores as catalyst could induce a significant decrease of the tarry oil yield and a significant increase of the phenols concentration in aqueous and liquid phase oils. The diffusion efficiency of the reactive intermediates determined by pore size is supposed to be the most crucial parameter that determines the catalytic performance of ACs. The pore sizes of mesopores are much bigger than the sizes of reactive intermediates. Therefore, these pores could allow most of the reactive intermediates to diffuse quickly and to react within their pores.

    The study of the streamlined MACs production process development implies that iron species can be embedded into a carbon matrix via a lignin melting process. After the pyrolysis/carbonization of lignin and FeSO4 mixture under a nitrogen atmosphere, FeSO4 is decomposed and further reduced to form hagg iron carbide, which is buried into carbon matrix of biochars after a lignin melting. During subsequent steam gasification/activation process, iron species are gradually exposed from the carbon via the pore drilling and widening effect of steam. At the same time, the bare part of iron species are oxidized by steam to form magnetite. The maximum phosphorous adsorption capacity of produced MAC sample calculated using the best-fit Langmuir-Freundlich model is estimated to be 21.18 mg P/g. Further study of pyrolysis and subsequent steam gasification of metal dry impregnated lignin to produce MACs and H2-rich syngas implies that during the pyrolysis of FeSO4 impregnated lignin process, H2 is produced via the catalytic cracking of the volatiles. During the subsequent steam gasification of solid residues, H2 was mainly produced via the steam carbon reactions and the steam gas shift reactions. The maximum overall H2 yield of the integrated process is as high as 42.73 mol/kg-lignin. Also, approximately 70% of phosphorous in real domestic wastewater can be adsorbed by MACs produced from the same process after a treatment for 2 hours.

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  • Public defence: 2020-06-03 10:00 Publikt via ZOOM, Stockholm
    Li, Xiaojie
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Materials for advanced energy technology from quantum-mechanical modeling2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The present thesis addresses promising material solutions for fusion reactors from a theoretical point of view. We focus on two specific systems: W-based alloys used as plasma-facing materials and reduced activation ferritic/martensitic (RAFM, Ferich) steels used as structural materials of breeding-blanket. We aim to systematically investigate the alloying effects on the micro-mechanical properties of these body-centered cubic (bcc) solid solutions. The all-electron exact muffin-tin orbitals (EMTO) method in combination with the coherent-potential approximation (CPA) is the main tool for our theoretical studies. The knowledge of the elastic parameters and their solute-induced changes is important for alloy design and for a multi-scale modeling approach to the mechanical properties. We also explore the planar faults in the present Fe-based alloys.In part one, the effect of neutron transmutation elements on the elastic properties of the W-based alloys are calculated. Under intensive radiation, W transforms to Re/Os and thus there is a certain degree of Re/Os doping in the base alloy. Both Re and Os solute atoms shrink the lattice constant, which lead to increasing bulk modulus as the amount of Re or Os increases. The polycrystalline shear and Young’s moduli of W1−xyRexOsy (0 ≤ xy ≤0.06) enhance with the addition of Re but decrease with increasing Os level. From the variations of the Cauchy pressure, Poisson’s ratio, Pugh ratio B/G, and the ratio of cleavage energy to shear modulus for the dominant slip system, we conclude that the intrinsic ductility of the alloy increases with increasing Re and Os content. We use the energy difference between the face-centered cubic (fcc) and bcc structures to estimate the alloying effect on the ideal tensile strength in the [001] direction.In part two, we choose three RAFM steels: CLAM/CLF-1, F82H, and EUROFER97 and investigate the micro-mechanical properties of the main alloy phases at low temperature (0 K). Being the main building blocks of the RAFM steels, first the lattice parameters, elastic properties, surface energy and unstable stacking fault energy of ferromagnetic α-Fe and Fe91Cr9 are calculated for reference. For quantitative understanding, we present a detailed analysis of the calculated individual alloying effects of V, Cr, Mn, and W on the elastic properties of Fe91Cr9. A linear superposition of these individual rates on the elastic properties of RAFM steels is shown to reproduce well the values from ab initio calculations. The composition dependence of the elastic constants is decomposed into electronic and volumetric contributions and they are analyzed separately. Finally, the intrinsic ductility is evaluated through Rice’s phenomenological theory by using the ratio of surface and unstable stacking fault energies. The results are consistent with those obtained by the common empirical criteria.In part three, the temperature dependence (T ≤ 1120 K) of the isothermal singlecrystal and polycrystalline elastic parameters of α-Fe and CLAM are reported by using a first-principles based modeling approach. The effect of temperature on the strongly temperature-dependent elastic constants C11 T and CT' is reproduced, as well as that on derived isotropic elastic moduli. Weak changes in C12 T and C44 T with temperature are obtained. The approach is applied to predict the temperature effect on the elastic parameters of three RAFM steels. Contributions due to loss of longrange magnetic order and the combined effect of volume expansion and entropy are found to be important in determining the temperature dependence of the elastic parameters in all the materials investigated.In part four, the (100) and (110) surface energies and surface segregation energies of Fe1−xbCrxb binary alloys, xb ≤ 15 at.%, are computed. These alloys form the basic building blocks of RAFM steels and thus their surface properties are of fundamental importance for the modeling the mechanical behavior. The implications of these results for the surface alloy phase diagram are discussed. The surface chemistry of Fe-Cr(100) is characterized by a transition from Cr depletion to Cr enrichment in a critical bulk Cr composition window of 6 < xb < 9 at.%. In contrast, a nearly homogeneous Cr concentration profile is energetically favorable in Fe-Cr(110) surface. The strongly suppressed surface-layer relaxation at both surfaces is shown to be of magnetic origin. The compressive, magnetic contribution to the surface relaxation stress is found to correlate well with the surface magnetic moment squared at both surface terminations. The surface electronic structures are used to explain the stability of the Cr surface magnetic moments against bulk Cr content.

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  • Public defence: 2020-06-05 10:00 Stockholm
    von Witting, Emma
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    The ADAPT scaffold as a tool for diagnostic imaging and targeted therapy2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Molecular recognition, or the specific interactions between a protein and its ligand, is central to biology and a key factor for many different clinical and technical applications. Despite antibodies being only one of many different affinity proteins, it has by far been the most successful. However, their large size and complex structure can be limiting in terms of cost and stability. Furthermore, their effector functions can sometimes be undesired or even detrimental. Over the past decades, many alternative affinity proteins have emerged to overcome some of these limitations.

    The Albumin Binding Domain (ABD), originally present on the surface of certain bacterial cells, has previously been subjected to combinatorial protein engineering for the generation of ADAPTs (ABD Derived Affinity ProTeins) that bind to different targets. One of these, the ADAPT6, targets HER2 and has shown great promise as a tracer for radionuclide molecular imaging for diagnosis and stratification of HER2 positive patients. The work in this thesis has aimed to optimise the ADAPT6 tracer further and also describes the first-inhuman clinical trial for imaging of HER2-overexpressing breast cancer. The results establish that ADAPT6 is safe and well-tolerated by patients and able to detect primary tumours as well as metastases with very high contrast already 2 hours after injection. However, the high kidney uptake associated with its fast blood clearance prevents further use of ADAPT6 also in a therapeutic setting. By engineering the ADAPT6 to prolong its circulatory half-life and reduce the kidney uptake, this thesis has also aimed to explore the therapeutic potential of this molecule. As a first step towards this goal, the ADAPT6 was genetically fused to an ABD to allow for binding to a patient’s own serum albumin and hence avoid the same extent of renal filtration. Indeed, when evaluated in mice, fusion to ABD increased the retention in circulation by more than 200-fold and exhibited a dramatically decreased renal activity. Treatment of tumour-bearing mice with the ABD-fused ADAPT6 conjugated to a cytotoxic radionuclide significantly prolonged survival by more than two-fold and was not associated with any observable toxicity. Finally, this thesis also describes a novel combinatorial library from which several bispecific ADAPTs have been identified, binding to both albumin and other clinically relevant targets simultaneously. This miniature bispecific scaffold offers an opportunity to combine the benefits associated with small size such as good tissue extravasation and alternative administration routes while still maintaining a sufficient in vivo half-life.

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  • Public defence: 2020-06-03 14:00 F3, Stockholm
    Johannisson, Wilhelm
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Exploring structural carbon fiber composites for mass-less energy and actuation2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The energy consumption in transport is today a large contributor to global greenhouse emissions. One way of reducing these emissions is by electrification, which is an ongoing journey for the vehicle industry. The aeronautical industry has started investigations but are limited by the relatively low specific energy of batteries.

    One way to improve the specific energy of batteries is by making them multifunctional by combining them with other functions of the vehicle. When the battery is combined with a structural material, the resulting material is referred to as a structural battery. This structural battery ultimately performs the fundamental function of mechanical rigidity and the battery function provides almost mass-less energy. The idea of structural batteries has been around for a while, but its actual construction has not yet been understood.

    This thesis is focused on exploring the design and implications of structural batteries made from carbon fiber composites. The first section is focused on the construction of the structural battery. Specifically investigating a structural carbon fiber negative electrode with regards to its manufacturing, electrochemical properties and mechanical properties. The results show that the construction of a negative electrode for structural batteries is achievable. The next section is using the findings from the first section in exploring the implications of implementing a structural battery into vehicles with regards to weight saving and life cycle characteristics. The findings show that the structural batteries have the potential to decrease both weight and life cycle burdens. The last section presents the use of the structural carbon fiber negative electrodes as a morphing material controlled by applied electrical power. The morphing deformations are large and stationary when power is removed but the morphing rate of the material is limited. Additionally, it is solid state, lightweight and has an elastic modulus higher than aluminum with large morphing deformations.

    The long-term outcomes of a thesis are hard to predict, but the findings herein conclude that the technology of structural batteries have the potential to disrupt energy storage in transportation, as well as traditional actuation and morphing technologies.

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  • Khaitan, Pradhyumn
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    Dynamic safety zone-based path planning for reduction of unwanted emergency braking2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Autonomous vehicles are required to have higher standards of safety. To enforce this , different subsystems in the autonomous vehicle are categorised to different safety levels by the industry. The problem arises when these subsystems are required to interact with each other. The objective of this thesis is to build and study the interaction between two systems in an autonomous vehicle. The two systems here are the path planning and the emergency braking system (AEBS) which are assigned different safety levels. Model Predictive Control(MPC) is used to build the interaction between the path planning and the emergency braking system. The zone of activation of the emergency braking system is modelled as polygon and is called the safety zone for the autonomous vehicle. The shape of this polygon is a function of a decision variable of the MPC. With respect to the safety zone, Farkas’s lemma is used to further constrain the vehicle to stay within the boundary of the road and avoid static obstacles.Two scenarios are built and studied to see the implications of the interactions of these two different systems. To study this interaction, the simulations are carried out with and without the interaction of the safety zone with the path planning system. This helps us in visualizing and understanding the factors influencing the size and shape of the safety zone. Key results of this thesis are to demonstrate the unwanted activation of the AEBS and the adaptive shape changing nature of the safety zone as a part of the MPC. These results demonstrate the importance of the safety zone being a part of the MPC, to prevent unwanted activation of the AEBS. The analysis contained in this thesis provides a methodology by which these two different standard systems(AEBS and path planner) can be integrated in an autonomous vehicle.

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  • Jungstedt, Erik
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Montanari, Celine
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Östlund, Sören
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation. KTH, School of Chemical Science and Engineering (CHE), Centres, Biofibre Materials Centre, BiMaC.
    Berglund, Lars
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Mechanical properties of transparent high strength biocomposites from delignified wood veneer2020In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840Article in journal (Refereed)
    Abstract [en]

    Transparent wood (TW) based on delignified birch veneer and thermoplastic poly(methyl methacrylate) (PMMA) is investigated by uniaxial tensile tests and full-field strain analyses based on digital image correlation techniques. TW is considered as a composite of unidirectional fibers (wood veneer) in a matrix (PMMA). Four in-plane elastic constants along the material axes are reported to enable the usage of continuum mechanics and lamination theory. Longitudinal composite strength is as high as 270 MPa at a reinforcement content of only 25 vol%. The failure behavior is interpreted based on strain field development. Strong reinforcement effects were observed from delignified birch veneer. Despite the fragility of delignified veneers, this constituent provides unexpectedly high reinforcement due to the high cellulose content and favorable stress transfer mechanisms.

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  • Behrsin, Ingrid
    et al.
    De Rosa, Salvatore Paolo
    Philosophy and History, KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, History of Science, Technology and Environment.
    Contaminant, Commodity and Fuel: A Multi‐sited Study of Waste's roles in Urban Transformations from Italy to Austria2020In: International Journal of Urban and Regional Research, ISSN 0309-1317, E-ISSN 1468-2427, Vol. 44, no 1, p. 90-107Article in journal (Refereed)
    Abstract [en]

    This article traces the flow of municipal solid waste from southern Italy through a waste‐to‐energy facility and district heating system in Austria, examining the roles that waste's transformation from contaminant to commodity to fuel plays in interconnected, distributed, and contested urbanization processes. It contends that, while metabolic circulation hides socioecological costs in one place to facilitate valorization in another, specific spatial configurations emerge through territorialization—of waste economies, in this case—providing the spatial base to realize metabolic flows and to anchor political narratives. A decisive effect is that certain patterns of urbanization become locked‐in, impeding alternative metabolic transitions and spatial configurations. Attending to the coproduction of three sites—Naples, Italy; Zwentendorf, Austria; and St Pölten, Austria—through the circulation and transformation of waste and energy the article provides an empirical multi‐sited case study of a political ecology of urbanization.

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  • Public defence: 2020-06-04 10:00 F3, Stockholm
    Morra, Pierluigi
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Modelling and control of turbulent and transitional flows2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The dynamics of fluid motion can accurately be described by the Navier– Stokes equations. Manipulating these equations to reduce their complexity but preserving their main characteristics has always been a key research activity in the field of fluid mechanics. Effort has been made to provide high-fidelity models for wall-bounded turbulent flows or reduced-order models for applications such as drag reduction, lift enhancement, or noise suppression. Model order reduction has also been employed for studying the dynamics of the Navier-Stokes equations. In this PhD thesis, the emphasis is on providing computationally inexpensive methods for industrial applications.

    Numerical simulations are performed to tackle model order reduction for flow control of transitional boundary-layer flows for drag reduction. It is assumed that localized wall sensors and actuators are available, and that only the time signals accessible in experiments are provided. Thus, a method to include unknown high-dimensional input disturbances in a reduced-order model of a transitional boundary-layer flow is presented. The method is applied for the design of an optimal controller for drag reduction through delay of transition. Moreover, the role of the actuator is discussed and a comparison between realistic actuators and actuators computed using optimization methods is presented. Here, the emphasis is on the effectiveness of the actuators for the studied flow control cases.

    Numerical simulations are also performed to tackle high-fidelity modeling in wall-bounded turbulent flows. The accuracy of the resolvent analysis in predicting the most energetic flow structures in a wall-bounded turbulent flow is quantified for different temporal frequencies. A direct comparison between the predictions from the resolvent analysis and the flow structures identified in DNS data is presented. Moreover, the beneficial effects attained with the inclusion of the Reynolds-stresses via an eddy-viscosity model are clarified for flows with friction Reynolds number up to 1007.

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  • Omerovic, Ismet
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    The Actualization of Innovation: A case study on how the district administrations in the City of Stockholm actualize innovation2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As innovation plays a predominant role in gaining competitive advantage, profit driving companies within the private sector have found ways to use innovation to succeed on the market. Although the public sector works according to a different set of logic, the demand for innovation within the public sector has been found to be growing due to increasing user needs, as well as increasing expectations on the effectiveness, availability and the quality of the public services. The district administrations, that are partly responsible for delivering such services in the City of Stockholm, face currently also various challenges such as a demographical development. A central strategy for innovation currently exists, but as such is equally important as systematical processes in order to build a long-term lasting capacity for innovation, it was unclear to this point if systematical processes are used at the district administrations to actualize innovation. Therefore, this research investigated how innovation was actualized at the district administrations in the City of Stockholm in order to identify if systematical processes were used, as well as to find which factors potentially hinder innovation from being actualized with systematics. Only the implications of the top-management were examined and the research was conducted as a case study of qualitative sort where interviews with top-executives, projects leaders and managers were conducted in the process. This research found that the district administrations neither address nor facilitate innovation in a systematic manner, as systematical processes were found to be absent for such purposes. Innovation is rather actualized in an unstructured manner, as no systematics was found to be used in relation to any of the stages in the innovation process. Among the factors that were found to affect the use of systematic processes was the absence of a climate that facilitates innovation, the lack of know-how knowledge for managing innovation, as well as communication deficiencies. Internal strategies were found to be absent and continuous learning was found to not be facilitated adequately, as well as knowledge in general was found to not be sufficiently enhanced. Heavy workloads and emergency driven operations cause difficulties to actualizing innovation with systematics. Finally, as much of the daily work at district administrations is budget-driven and as innovation is not referred to as explicit objectives, innovation is overshadowed by the tasks that are related to the daily operations at the district administrations.

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  • Jansson, Caroline
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Management.
    Applying Earned Value Managementin Service Projects: A Case Study at Saab Surveillance2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    For organisations to stay competitive, continuous improvements and development are needed.Organisations handling complex services, structured in projects, find difficulties in understanding the project performance. Understanding the project performance is important in order to achieve the ability to implement improvements and development activities in projects. Furthermore, project performance needs to be understandable for the whole organisation in order to be able to prioritize. There are several applicable methods available for handling the evaluation of performance. One method is Earned Value Management, EVM, which incorporates project scope, schedule and cost parameters in order to create project control.The purpose of this study is to investigate how EVM could be implemented for evaluating performance in projects handling repair and maintenance based on the EVM standard ANSI/EIA-748. The purpose is also to identify needed adaptations in the projects to make it possible to implement EVM. The EVM standard contains important steps and activities needed in order to be able to aggregate values and evaluate performance.The result of this study presents adaptations needed for EVM implementation based on the EVM standard ANSI/EIA-748. The study concludes that some structural and managerial changes need to be done before EVM can be implemented. The organisation needs to formulate common guidelines for structuring work and organisations, as well as formulate and define common reporting structures for documentation and reporting. In addition, the way of handling planning, and budgeting need to be reviewed and customised. The organisation also needs to continuously work with the knowledge and understanding about the importance of the business and the evaluation, to create a successful EVM implementation and a sustainable business.

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  • Li, Yuanyuan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Yang, Xuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Fu, Qiliang
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Rojas, Ramiro
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Yan, Max
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Berglund, Lars
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Towards centimeter thick transparent wood through interface manipulation2018In: International Journal of Materials and Chemistry, ISSN 2166-5346, E-ISSN 2166-5354, Vol. 6, p. 1094-1101Article in journal (Refereed)
    Abstract [en]

    Transparent wood is an attractive structural material for energy-saving buildings due to its high optical transmittance, good thermal insulation, and high toughness. However, thick highly transparent wood is challenging to realize. In the current work, highly transparent wood (1.5 mm) with a transmittance of 92%, close to that of pure PMMA (95%), is demonstrated. The high transmittance was realized by interface manipulation through acetylation of wood template. Both experiments and electromagnetic modeling support that the improved transmittance is mainly due to elimination of interface debonding gap. By applying this method, a centimeter-thick transparent wood structure was obtained. The transparent wood could be used as a substrate for an optically tunable window by laminating a polymer dispersed liquid crystal (PDLC) film on top. The techniques demonstrated are a step towards the replacement of glass in smart windows and smart buildings.

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  • Svensson, Anton
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Naval Systems.
    Composite Hydrofoil Manufacturing For An Autonomous Surface Vessel2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The use of composite materials has been common in small craft boat building for a long time. In recent years, there has been a huge push in the development of different types of appendages such as hydrofoils. These hydrofoils are commonly manufactured in carbon fibre composites, due to high requirements in weight and stiffness. These appendages can be difficult to develop and complex to manufacture since manufacturing methods for composites are complex. KTH Royal Institute of Technology is developing a hydrofoil concept for a small autonomous vessel. The hydrofoil is designed to be built in carbon fibre composite. It requires to have control surfaces in order to maintain a stable flight and the electrical propulsion is located on it as well. This makes this hydrofoil one of a kind and the parts that build up the hydrofoil have more specifications than just to be designed from a hydrodynamic and structural point of view like a conventional hydrofoil. This thesis investigated what manufacturing methods should be used when building a hydrofoil like this.

    Existing manufacturing methods such as vacuum infusion and different types of prepreg moulding have been reviewed and are presented early in the report. The methods have been analyzed from the perspective of the components of the hydrofoil, resulting in an initial manufacturing strategy for the different components. The strategy includes everything from a 3D-model of the part to a finished product, including sheet design, mould manufacturing and moulding of the part.

    Several tests were conducted before a component was successfully manufactured. Each test was evaluated and presented in such a manner that the reader can understand what is needed to be improved and why. The conclusions of each test lead to an improvement of the manufacturing technique and a new test until the final result was acquired. The tests were examined with a microscope to verify the quality of the part. Then a weight fraction analysis was made on these parts. The final conclusions of the thesis gave successful methods to manufacture the different parts of the hydrofoil. A fast manufacturing method for product development of complex parts was achieved. The resulting parts from the tests show good quality from the analysis.

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