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  • 124251.
    Ribbenfjärd, David
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Engdahl, Göran
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Modeling of dynamic hysteresis with Bergqvist's lag model2006Conference paper (Refereed)
    Abstract [en]

    This work presents a dynamic hysteresis model based on Bergqvist's lag model for static hysteresis and Bertotti's model for dynamic hysteresis. This new model is used for simulation of magnetic materials. The simulation results are compared with measurements of the amorphous alloy Metglas 2605 S-2 and the transformer steel Surahammar M5. The simulated results show good agreement with the measurements.

  • 124252.
    Ribbenfjärd, David
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Engdahl, Göran
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Novel method for modelling of dynamic hysteresis2008In: IEEE transactions on magnetics, ISSN 0018-9464, E-ISSN 1941-0069, Vol. 44, no 6, p. 854-857Article in journal (Refereed)
    Abstract [en]

    The dynamic hysteresis model for magnetic materials presented by Bertotti [1] uses the classical eddy current expression, where the applied field is assumed to penetrate the material homogenously. However, for this to be valid for a material exposed to a field varying with a frequency in the kilohertz range or higher, the material has to be very thin, e.g., a thin laminate, typically thinner than 0.1 mm. In this paper a novel method is presented. The idea is to combine Bertotti's model with a Cauer circuit and divide the material into a number of sections, each exhibiting different magnitude of magnetic field caused by the eddy current shielding. Furthermore, the eddy currents are modeled by "magnetic inductances" instead of the classical eddy current expression. This modelling technique yields simulation results that agree very well with measurements.

  • 124253.
    Ribbenfjärd, David
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Engdahl, Göran
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Optimization of the geometrical selection of subsections in Cauer circuit models of laminated magnetic materials at high frequencies2008In: Proceedings IEEE Conference on Electromagnetic Field Computations, 2008, p. 337-Conference paper (Refereed)
  • 124254.
    Ribbenfjärd, David
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Engdahl, Göran
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Time-domain transformer model in Dymola2006In: Proceedings of IC-SCCE, 2006Conference paper (Refereed)
  • 124255.
    Ribbenfjärd, David
    et al.
    KTH, Superseded Departments (pre-2005), Signals, Sensors and Systems.
    Lindmark, Björn
    KTH, Superseded Departments (pre-2005), Signals, Sensors and Systems.
    Karlsson, Bo
    Eklund, Lars
    Improved vehicle antenna system for measurement of 3G radio coverage2004In: Joint COST 273/284 Workshop on Antennas and Related System Aspects in Wireless Communications, 2004, p. 189-193Conference paper (Refereed)
  • 124256.
    Ribbenfjärd, David
    et al.
    KTH, Superseded Departments (pre-2005), Signals, Sensors and Systems.
    Lindmark, Björn
    KTH, Superseded Departments (pre-2005), Signals, Sensors and Systems.
    Karlsson, Bo
    Eklund, Lars
    Omnidirectional Vehicle Antenna for Measurement of Radio Coverage at 2 GHz2004In: IEEE Antennas and Wireless Propagation Letters, ISSN 1536-1225, Vol. 3, no 1, p. 269-272Article in journal (Refereed)
    Abstract [en]

    To accurately determine radio coverage, it is necessary to have an omnidirectional antenna pattern. Our measurement results show that this is not the case for an antenna mounted on a vehicle. We present two improved antenna solutions with an additional ground plane in the form of a disk and a corrugated cone. The peak-to-peak variation in the horizontal plane is then reduced from 5 to 2.5 dB and 1.7 dB, respectively. Although our results are limited to a medium-size vehicle and frequencies around 2 GHz, we believe that they are of interest for all measurements where high accuracy is desired.

  • 124257.
    Ribbenhed, Malin
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Karakterisering av lakvatten genom fraktionering och multivariat modellering1998Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The background to this thesis is that leachates from landfills, containing for example municipal wasteand industrial waste, could be hazardous to the environment. Today, there does not exist anystandardised method for characterisating leachates. At IVL, The Swedish Environmental ResearchInstitute, a project is under way whose purpose is to develop a method for characterisating leachatesfrom landfills. This thesis is a part of the characterisation and the purpose of the study is tocharacterise leachates by fractionation and multivariate modelling.The aim of the former was to fractionate leachates from landfills into different particle and colloidsizes by filtration. The purpose was also to characterise the filtrates in terms of organic content, metalcontent and toxicity. Also the influence of freezing the samples before filtration were evaluated.Furthermore, the suspension was measured during a four week period to evaulate for how long aleachte is stable with respect to the amount of suspended material.The multivariate modelling included listing relevant data, developing a conceptional modell of alandfill and to doing a multivarite data analysis (MVA) on the data. The goal was to estimate if thedata was sufficient for predicting the emissions in the leachates from a number of landfills by MVA.The results from the fractionation study showed that the amount of organic material could be reducedin the leachte sampels by filtration through 1000 Dalton or less. The results also indicated that Pb, Crand Cu could be reduced in the samples by filtration through 0.45 μm or less. No difference intoxicity was found after filtration through a 0.45 μm filter. There was no significant differencebetween fresh and frozen samples. The amount of suspended material increased during a four weekperiod. The greatest increase appeared during the first week.The conlusion from the multivariate modelling was that it is possible to use MVA for modelling onelandfill at a time. On the other hand, it was not possible to modell all the landfills in one model

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    FULLTEXT01
  • 124258.
    Ribbenstedt, Marcus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Salvati, Nick
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Simulation driven design of timber bolster in fibre composite2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The primary objective of this thesis is to investigate a simulation and optimisation based methodology using fibre composite materials to lower the weight of timber bolsters. The timber bolsters secure the timber from falling off the truck during loading and transport. A lighter forestry truck is beneficial for several reasons such as increased payload and fuel efficiency and a decreased environmental impact.

    This thesis includes a concept study for a bolster made of fibre composites. Carbon and glass fibres together with polyurethane were chosen as material system and the recommended manufacturing methods were pultrusion and resin transfer moulding. A study of the economy related to the timber transport was conducted during the concept phase to investigate the potential business case.

    The thesis also includes an optimisation of the generated concept. The optimisation focused on geometry and fibre layup. By the use of optimisation the weight was reduced from the initial 136 kg of aluminium to 87 kg of glass and carbon fibre. The optimised design was compared with today’s aluminium bolsters and indicated that the composite bolster is realistic from an economic perspective.

    A methodology for analysing bolted joints in fibre composites was developed. The analysis was made using the finite element method and resulted in a comparison between different failure criteria. Based on the results it can be concluded that the prediction of failure differs significantly depending on used failure criterion and tests are needed for verification.

    Finally a simulation was made to verify the structures response to an impact. The simulation was compared with calculations using energy equations showing a fairly good agreement.

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  • 124259.
    Ribberheim, Olle
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Mathematics (Div.).
    Carbon Intensity Estimation of Publicly Traded Companies2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this master thesis is to develop a model to estimate the carbon intensity, i.e the carbon emission relative to economic activity, of publicly traded companies which do not report their carbon emissions. By using statistical and machine learning models, the core of this thesis is to develop and compare different methods and models with regard to accuracy, robustness, and explanatory value when estimating carbon intensity. Both discrete variables, such as the region and sector the company is operating in, and continuous variables, such as revenue and capital expenditures, are used in the estimation. Six methods were compared, two statistically derived and four machine learning methods. The thesis consists of three parts: data preparation, model implementation, and model comparison. The comparison indicates that boosted decision tree is both the most accurate and robust model. Lastly, the strengths and weaknesses of the methodology is discussed, as well as the suitability and legitimacy of the boosted decision tree when estimating carbon intensity.

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  • 124260.
    Ribberheim, Olle
    et al.
    KTH, School of Engineering Sciences (SCI).
    Skaredotter, Erika
    KTH, School of Engineering Sciences (SCI).
    En multivariabel regressionsanalys av priset på utsläppsrätter i EU2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this bachelor thesis in applied mathematics and engineering physicsis to develop a model to describe the price of emissions allowances in EuropeanUnion Emission Trading Scheme, EU ETS, a scheme created to systematically re-duce carbon dioxide emissions with market forces in a free market. With the help ofstatistical regression, the core of the project is to explain the price of these emissionallowances by creating a model based on free available data from both microeconomicand macroeconomic factors in Europe. Stock indices, interest rates, electricity price,and inflation rates are examples of factors that were used. Two models were devel-oped, one with data points from mid-2010 to March 2019 and one with data pointsfrom mid-2010 until March 14, 2018, when a new directive was voted through re-garding the premises of the trading scheme. The models were developed throughstatistical methods such as identification of outliers, detection of multicollinearity,cross validation, and bootstrapping in order to create a model as suitable as pos-sible. Afterward, the model’s credibility and legitimacy were discussed, as well aspossible areas of improvement and further studies to improve the model and theunderstanding of the pricing.

     

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  • 124261. Ribbing, C.
    et al.
    Cederström, Björn
    KTH, Superseded Departments (pre-2005), Physics.
    Lundqvist, M.
    Microfabrication of saw-tooth refractive x-ray lenses in low-Z materials2003In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 13, no 5, p. 714-720Article in journal (Refereed)
    Abstract [en]

    Saw-tooth x-ray refractive lenses have been fabricated in silicon, epoxy and diamond. Silicon lenses were made by anisotropic wet etching of single crystalline silicon. Epoxy lenses were moulded from silicon masters. Diamond lenses were replicated by. chemical vapour deposition on silicon masters and subsequent sacrificial etching of silicon. Beryllium saw-tooth test structures were embossed using a diamond master. Silicon and epoxy lenses gave sub-micron focal lines and provided gains of up to 40 when tested in a synchrotron set-up. Focal lengths ranged from 0.33 to 0.61 m for x-ray energies between 14 and 30 keV.

  • 124262. Ribbing, C.
    et al.
    Cederström, Björn
    KTH, Superseded Departments (pre-2005), Physics.
    Lundqvist, M.
    Microstructured diamond X-ray source and refractive lens2003In: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 12, no 11-okt, p. 1793-1799Article in journal (Refereed)
    Abstract [en]

    This paper treats microstructured CVD diamond in two X-ray applications, a miniature X-ray source and a refractive X-ray lens. The X-ray source consists of boron doped diamond membrane electrodes and an intermediate insulator. The cathode has a pyramidal shape, which is field-emitting and the anode is a metal film on a diamond membrane. Anode radiation emerges through both membrane electrodes. The source has not been vacuum sealed, therefore, all measurements so far have been made in a vacuum chamber. The refractive X-ray lens has saw-tooth geometry and a tunable focal length. It was made by microwave plasma assisted CVD of diamond onto anisotropically etched silicon masters. The lens has been used for one-dimensional focusing of a synchrotron beam to 1.9 mum line width.

  • 124263. Ribbing, C.
    et al.
    Karlsson, G.
    KTH, Superseded Departments (pre-2005), Physics.
    Palmskog, Göran
    KTH, Superseded Departments (pre-2005), Physics.
    Brismar, Hjalmar
    KTH, Superseded Departments (pre-2005), Physics.
    Laurell, Fredrik
    KTH, Superseded Departments (pre-2005), Physics.
    Spiekermann, Stefan
    KTH, Superseded Departments (pre-2005), Physics.
    Nordborg, J.
    Rydholm, J.
    Karlsson, H.
    Improved contrast in confocal microscopy by using a blue frequency doubled diode-pumped solid-state laser2004In: Conference on Lasers and Electro-Optics, 2004. (CLEO), 2004Conference paper (Refereed)
    Abstract [en]

    The standard Ar ion laser in a confocal microscope was replaced with an intra-cavity frequency doubled Nd:YAG laser operating at 473 nm. The fluorescence image quality suggests that excitation at 473 nm could be preferable.

  • 124264.
    Ribca, Iuliana
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Lignin-Based Thermosets with Tunable Mechanical and Morphological Properties: A Study of Structure-Property Relationships2023Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nowadays, there is an urgent need to decrease our dependence on fossilresources and shift towards the use of renewable resources for advancingsustainable development. Utilizing renewable and bio-based raw materials,such as lignocellulosic biomass, for designing new materials is a promisingapproach to promote this objective. The main components of lignocellulosicbiomass are cellulose, hemicellulose, and lignin. Lignin is the most abundantaromatic biopolymer in nature and it is produced on a large scale fromchemical pulping processes as technical lignin. Lignin has the potential as asustainable and renewable alternative to fossil-based aromatics in variousapplications, e.g. thermosetting resins.

    Technical lignin has a complex and heterogeneous structure, with arelatively low chemical reactivity. It is characterized by a high dispersity, thepresence of various functional groups that are unevenly distributed along thelignin chains, and various interunit linkages between the monoaromatics. Toovercome the challenges associated with lignin heterogeneity, technicallignin can be fractionated and/or chemically modified.

    In this work, LignoBoost Kraft lignin was used as a starting material toproduce lignin-based thiol-ene thermosets. Firstly, lignin was fractionatedusing two approaches: 1) sequential solvent fractionation, and 2) microwaveassistedextraction. These fractionation approaches enabled access to ligninfractions with unique and tunable properties. Subsequently, lignin waschemically modified, in particular through allylation. Two allylation reagentswere used: allyl chloride and diallyl carbonate. The use of allyl chlorideenables a selective allylation of the phenolic OH groups, leaving the aliphaticand carboxylic acid OH groups unmodified. On the other hand, diallylcarbonate can react with all the aforementioned OH groups, leading to ahigher degree of allylation. Subsequently, allylated lignin was thermallycross-linked with various polyfunctional thiols, leading to thiol-enethermosets. The structure-property relationships of the thermosets wereinvestigated by varying several parameters, including the lignin source,fractionation approach, chemical modification, and thiol cross-linker. Byadjusting these parameters, various thermosets with tunable mechanical andmorphological properties were produced. Understanding the structurepropertyrelationships of these bio-based materials is crucial for identifyingpotential applications.

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    Lignin-Based Thermosets with Tunable Mechanical and Morphological Properties
  • 124265.
    Ribca, Iuliana
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Jawerth, Marcus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Brett, Calvin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany.
    Lawoko, Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Schwartzkopf, Matthias
    Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany.
    Chumakov, Andrei
    Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany.
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany.
    Johansson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Exploring the Effects of Different Cross-Linkers on Lignin-Based Thermoset Properties and Morphologies2021In: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 9, no 4, p. 1692-1702Article in journal (Refereed)
    Abstract [en]

    The search for sustainable material solutions has put lignin as one of the prime candidates for aromatic building blocks in macromolecular materials. The present study aimed to demonstrate how lignin-based thermoset resins can be utilized in combination with different cross-linkers. Kraft lignin was used to produce thermosets with tunable mechanical and morphological properties. The lignin-based thermosets were obtained via a thermally induced thiol–ene reaction. The first part of this work was focused on Kraft lignin solvent fractionation and chemical modification of the ethanol soluble fraction. Chemical analysis indicated that the allylation process was selective toward phenolic hydroxyl groups. SAXS and SEM studies demonstrated that solvent fractionation and allylation processes affected the molecular and nanoscale morphological characteristics of lignin. The second part’s focus was on how the properties of thermosets can be tuned by using three different cross-linkers. The dynamic mechanical and morphological properties of three different thermosets were investigated via DMA, SAXS, and WAXS techniques. The three different thermosets exhibit similar molecular morphology but different storage modulus and glass transition temperature. In this work, it was shown that despite lignin’s heterogeneity it was possible to produce thermosetting materials with tunable properties.

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    Exploring the effects of different cross-linkers on lignin-based thermoset properties and morphologies
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    SI
  • 124266.
    Ribca, Iuliana
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Sochor, Benedikt
    Deutsches-Elektronen Synchrotron (DESY).
    Betker, Marie
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fiberprocesser. Deutsches-Elektronen Synchrotron (DESY).
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. Deutsches-Elektronen Synchrotron (DESY).
    Lawoko, Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Sevastyanova, Olena
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Meier, Michael A.R.
    Institute of Organic Chemistry (IOC), Materialwissenschaftliches Zentrum MZE, Karlsruhe Institute of Technology (KIT), Straße am Forum 7, 76131 Karlsruhe, Germany;Institute of Biological and Chemical Systems─Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
    Johansson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Impact of lignin source on the performance of thermoset resins2023In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 194, p. 112141-112141, article id 112141Article in journal (Refereed)
    Abstract [en]

    A series of different technical hardwood lignin-based resins have been successfully synthesized, characterized, and utilised to produce thiol-ene thermoset polymers. Firstly, technical lignin was fractionated and allylated, whereafter it was crosslinked with a trifunctional thiol. Structural and morphological characteristics of the lignin fractions were studied by 1H NMR, 31P NMR, SEC, FTIR, DSC, TGA, and WAXS. The hardwood lignin fractions have a high content of C5-substituted OH groups. The WAXS studies on lignin fractions revealed the presence of two π-π stacking conformations, sandwiched (4.08–4.25 Å) and T-shaped (6.52–6.91 Å). The presence of lignin superstructures with distances/sizes between 10.5 and 12.8 Å was also identified. The curing reaction of the thermosets was investigated by RT-FTIR. Almost all thermosets (excepting one fraction) reached 95% of the thiol conversion in less than 17 h, revealing the enhanced reactivity of the allylated hardwood lignin samples.

    The mechanical properties of the thermosets were investigated by DMA. The curing performance, as well as the final thermoset properties, have been correlated to variations in chemical composition and morphological differences of lignin fractions. The described results clearly demonstrate that technical hardwood lignins can be utilized for these applications, but also that significant differences compared to softwood lignins have to be considered for material design.

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    Impact of lignin source on the performance of thermoset resins
  • 124267.
    Ribca, Iuliana
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Sochor, Benedikt
    Deutsches-Elektronen Synchrotron (DESY),.
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Lawoko, Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Meier, Michael A. R.
    Institute of Organic Chemistry (IOC), Materialwissenschaftliches Zentrum MZE, Karlsruhe Institute of Technology (KIT).
    Johansson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Effect of Molecular Organization on the Properties of Fractionated Lignin-Based Thiol-Ene Thermoset MaterialsManuscript (preprint) (Other academic)
    Abstract [en]

    In this study, the combination of sequential solvent fractionation of technical Kraft lignin were followed by allylation of most OH functionalities to give highly functional thermoset resins. All lignin fractions were highly functionalized on the phenolic (≥95%) and carboxylic acid OH (≥85%), and to a significant extent on the aliphatic OH moieties (between 43 and 75%). The resins were subsequently cross-linked using thiol-ene chemistry. The high amount of allyl functionalities resulted in a high cross-link density. DMA measurements showed that thioether content dominates the performance of these thermosets with a glass transition temperature (Tg) between 73 and 99 °C and with a storage modulus between 1.9 and 3.8 GPa for all thermosets. The lignin fractions and lignin-based thermosets morphology, at nanoscale, was studied by wide angle X-ray scattering measurements (WAXS). Two π-π stacking interactions were observed: sandwich (≈4.1–4.7 Å) and T-shaped (≈5.5–7.2 Å). The introduction of allyl functionalities weakens the T-shaped π-π stacking interactions. A new signal corresponding to a distance of ≈3.5 Å was observed in lignin-based thermosets, which was attributed to a thioether organized structure. At the same time, a lignin superstructure, was observed with a distance/size corresponding to 7.9-17.5 Å in all samples.

  • 124268. Ribeiro da Silva, E. H. D.
    et al.
    Shinohara, A. C.
    Pinheiro de Lima, E.
    Angelis, Jannis
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Management. Research Institute of Industrial Economics, Grevgatan 34, Stockholm, 10215, Sweden.
    Machado, C. G.
    Reviewing digital manufacturing concept in the Industry 4.0 paradigm2019In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 81, p. 240-245Article in journal (Refereed)
    Abstract [en]

    Digitalization of manufacturing is once again on the industry application research agenda and Digital Manufacturing plays a fundamental role in this process. However, there is a lack of commonality in the literature about the purpose of Digital Manufacturing. The purpose of this paper is to analyze the concept and application domain of Digital Manufacturing considering the increasingly established Industry 4.0 paradigm. Based on a content analysis concepts are framed, and new technological characteristics identified. The paper contributes to a better understanding of the future challenges that companies face by positioning Digital Manufacturing conceptually and delimiting its application domain.

  • 124269. Ribeiro da Silva, Elias
    et al.
    Angelis, Jannis
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Managing scarcity - the case of Electric Vehicles batteries in extended supply chains2021Conference paper (Refereed)
  • 124270.
    Ribeiro da Silva, Elias
    et al.
    KTH.
    Angelis, Jannis
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Pinheiro de Lima, Edson
    Supplier integration through Digital Manufacturing: A SME paradox2018In: Proceedings of the 2nd SC4 Network International Symposium on Supply Chain 4.0. Digital Transformation in SME, 2018Conference paper (Refereed)
  • 124271.
    Ribeiro da Silva, Elias
    et al.
    University of Southern Denmark, Department of Technology and Innovation. Alison 2, DK-6400 Sønderborg, Denmark.
    Lohmer, Jacob
    Technische Universität Dresden, Chair of Business Management, esp. Logistics. Mommsenstr. 13, 01062 Dresden, Germany, esp. Logistics. Mommsenstr. 13.
    Rohla, Michelle
    University of Southern Denmark, Department of Technology and Innovation. Alison 2, DK-6400 Sønderborg, Denmark.
    Angelis, Jannis
    KTH, School of Industrial Engineering and Management (ITM).
    Unleashing the circular economy in the electric vehicle battery supply chain: A case study on data sharing and blockchain potential2023In: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 193, article id 106969Article in journal (Refereed)
    Abstract [en]

    Electric vehicles are perceived as a key technology to make mobility more sustainable, leading to a sharp rise in electric battery production and use. However, electric vehicle batteries are only a sustainable solution if they support decreasing the total impact of the supply chain, which makes circularity initiatives a key element in this transition. Currently, this is limited by the data sharing among actors in the supply chain on critical information needed to support a circular economy approach. In this study we explore how data sharing and information technology support the development of circularity in electric vehicle supply chains and examine the role of blockchain technology to address the circularity needs of battery tracking and capability sharing. To allow a comprehensive analysis, we conduct a case study in the electric vehicle battery supply chain, including companies from multiple tiers to capture all relevant perspectives. The results show that data sharing supports extended value chain activities, evolving from a linear to a circular supply chain perspective. It also indicates that blockchain technology supports removing existing barriers for a circular economy by facilitating transparency and traceability, especially for second-life applications beyond the dominant players in this industry.

  • 124272. Ribeiro da Silva, Elias
    et al.
    Shinohara, A
    Nielsen, C
    Pinheiro de Lima, Edson
    Angelis, Jannis
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Operating Digital Manufacturing in Industry 4.0: the role of advanced manufacturing technologies2020In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 93, p. 174-179Article in journal (Refereed)
    Abstract [en]

    This study analyzes the application domain of Digital Manufacturing while considering the new industrial paradigm. Based on content analysis, joint applications of digital manufacturing tools and advanced manufacturing technologies are framed and technological trends identified. The results reveal a new comprehensive framework that defines the application domain of digital manufacturing in Industry 4.0, as well as how digital manufacturing operates within Industry 4.0. The presented framework covers manufacturing life cycle phases, digital manufacturing tools used in each phase, and Industry 4.0 technologies used with the respective tools. The study contributes by positioning digital manufacturing conceptually and delimiting its application domain.

  • 124273. Ribeiro, E.
    et al.
    Batista, F.
    Trancoso, I.
    Lopes, José
    KTH, School of Computer Science and Communication (CSC), Speech, Music and Hearing, TMH.
    Ribeiro, R.
    De Matos, D. M.
    Assessing user expertise in spoken dialog system interactions2016In: 3rd International Conference on Advances in Speech and Language Technologies for Iberian Languages, IberSPEECH 2016, Springer Publishing Company, 2016, p. 245-254Conference paper (Refereed)
    Abstract [en]

    Identifying the level of expertise of its users is important for a system since it can lead to a better interaction through adaptation techniques. Furthermore, this information can be used in offline processes of root cause analysis. However, not much effort has been put into automatically identifying the level of expertise of an user, especially in dialog-based interactions. In this paper we present an approach based on a specific set of task related features. Based on the distribution of the features among the two classes – Novice and Expert – we used Random Forests as a classification approach. Furthermore, we used a Support Vector Machine classifier, in order to perform a result comparison. By applying these approaches on data from a real system, Let’s Go, we obtained preliminary results that we consider positive, given the difficulty of the task and the lack of competing approaches for comparison.

  • 124274. Ribeiro, L.
    et al.
    Barata, J.
    Onori, Mauro A
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Hanisch, C.
    Hoos, J.
    Rosa, R.
    Self-organization in automation - The IDEAS pre-demonstrator2011In: IECON Proceedings (Industrial Electronics Conference), 2011, p. 2752-2757Conference paper (Refereed)
    Abstract [en]

    While the application of IT in automation gains traction, mostly motivated by the introduction of Service Orientated Approaches and Multiagent modelling, it is sometimes unclear to practitioners what is the full potential and boundaries of such concepts and technologies. The FP7 IDEAS project is focused in the design and development of Multiagent systems in a Mechatronic context which, to a great extent, implies that Mechatronic Agents must consider and respect mechanical/physical constraints while delivering the widely acknowledged (yet elusively demonstrated) characteristics that may render Agent-based control unique in respect to tolerance to disturbances, plug-ability and scalability. In this context, the present paper details the preliminary proof of concept prototype that validates the IDEAS Mechatronic Agent Architecture. The focus of this early demonstrator is to enlighten on how self-organization, inspired by the Evolvable Assembly System (EAS) Paradigm, can be exploited towards promoting the above mentioned characteristics. The main lessons learned, open points and future developing directions are distilled as the prototype is presented.

  • 124275. Ribeiro, L.
    et al.
    Barata, J.
    Onori, Mauro
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering. EPS Group, Sweden.
    Hoos, J.
    Industrial Agents for the Fast Deployment of Evolvable Assembly Systems2015In: Industrial Agents: Emerging Applications of Software Agents in Industry, Elsevier, 2015, p. 301-322Chapter in book (Other academic)
    Abstract [en]

    Recent roadmaps, ranging from ManuFuture to Industrie 4.0, all stress that true industrial sustainability will require far higher levels of a system's autonomy and adaptability. The ability to plug and produce modular equipment is a central research topic in this context. The design and implementation of such a system is not a trivial task and different solutions have been previously documented. In this context, the present chapter discusses an agent-based architecture that supports the plug and produce of value-adding equipment-for example, stations, tools, and transport equipment such as conveyors and AGVs. The architecture focus both in the reconfiguration and control aspects explore the decoupled nature of the agent-based solution as a basis of the construction of inherently robust systems. The chapter details the main design and implementation decisions and assesses both the lessons learned and the potential benefits in the context of two industrial prototypes.

  • 124276. Ribeiro, L.
    et al.
    Dias-Ferreira, Joao
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Moura, C.
    Barata, J.
    A network inference tool for JADE-based systems2014In: Proceedings - 2014 12th IEEE International Conference on Industrial Informatics, INDIN 2014, 2014, p. 398-403Conference paper (Refereed)
    Abstract [en]

    This article describes the first version of a tool designed to infer the network characteristics of JADE-based multiagent systems. The rationale behind the tool is that systems in general and multiagent system in particular, often have some hidden dynamics that contribute to the emergence of desired and undesired characteristics. Traditional sniffing tools simply display the message exchange. The presented tool goes therefore beyond simple message sniffing and infers the agents' network based on the ongoing interactions and codifies it a format suitable for further processing in specialized network analysis tools. In particular the prosped tool identifies the most frequently used communication links and the messages associated with them. To demonstrate the behavior of the tool an exploratory system based on the Evolvable Production System paradigm is discussed and analyzed.

  • 124277. Ribeiro, Luis
    et al.
    Barata, José
    Cândido, Gonçalo
    Onori, Mauro
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Evolvable Production Systems: An Integrated View on Recent Developments2010In: Proceedings of the 6th CIRP-Sponsored International Conference on Digital Enterprise Technology, Berlin, Heidelberg: Springer Berlin Heidelberg , 2010, p. 841-854Conference paper (Refereed)
    Abstract [en]

    Evolvable Production Systems (EPS) is a fundamentally new paradigm to design, maintain and evolve industrial systems. It is a holistic approach supporting product/shop floor co-evolution and ensuring a tailored and balanced solution for sustainable enterprise development. Its core is engineered by distributed intelligence materialized in proactive and interacting shop floor assets. These intelligent building blocks include a wise interface design that ensures plug- Ability and promotes system integration and bio-inspired interaction mechanisms (control and monitoring/diagnosis) to emerge a consistent selforganizing response to production disturbances. In this article a short survey on recent technical and theoretical developments supporting the EPS paradigm is held

  • 124278. Ribeiro, M. S.
    et al.
    Correa, G. B., Jr.
    Bergman, Anders
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Nordstrom, L.
    Eriksson, O.
    Klautau, A. B.
    From collinear to vortex magnetic structures in Mn corrals on Pt(111)2011In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 83, no 1, p. 014406-Article in journal (Refereed)
    Abstract [en]

    We study the magnetic properties of small Mn ring-shaped clusters on a Pt(111) surface in the framework of density functional theory. We find that the Mn atoms possess large magnetic moments, of the order of 4 mu(B)/atom, and have dominating antiferromagnetic interatomic exchange interactions. A quantum confinement effect within the ringlike clusters was found, indicating that even very small clusters can be seen as quantum corrals. The antiferromagnetic exchange couplings lead to collinear magnetic arrangements in simple corrals, as well as complex noncollinear ordering, as vortexlike structures, for the case of corrals with particular geometry where antiferromagnetism becomes frustrated.

  • 124279.
    RIBEIRO ROSA, ANDRÉ MANUEL
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial marketing.
    Circular Economy in the Clothing Industry: Challenges and Strategies2016Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This  exploratory research  identifies  how  can  clothing companies  implement  textile recyclingtechnologies that help transition them to a sustainable circular economy business model, given the challenges of eco-innovation diffusion. The study is exploratory in nature, employs a literature review and a case study of Patagonia, the outdoor equipment and clothing company that pioneered the use of recycled fibers in the outdoor clothing industry and continues to have today several initiatives for diverting textile waste away from landfills.To implement textile recycling technologies, the company created the Worn Wear Program, the Common Threads Recycling Program and the possibility to return a worn-out garment to Patagonia’s distribution center by mail or from any store or local authorized dealer of Patagonia’s products. To make the recycling (or repurposing) of worn-out garments work, the company also established a repair department at its distribution center which receives all worn-out clothes sent for recycling or repurposing.

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  • 124280.
    Ribeiro-Ayeh, Steven
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Finite element modelling of the mechanics of solid foam materials2005Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Failure of bi-material interfaces is studied with the aim to quantify the influence of the induced stress concentrations on the strength of the interfaces. A simple point-stress criterion, used in conjunction with finite element calculations, is evaluated to provide strength predictions for bi-material bonded joints and inserts in polymer foam. The influence of local stress concentrations on the initiation of fracture at open and closed wedge bi-material interfaces is investigated. The joint combinations are analysed numerically and the strength predictions obtained from the point-stress criterion are verified in experiments.

    The predictions are made using a simple point-stress criterion in combination with highly accurate finite element calculations. The point-stress criterion was known from earlier work to give accurate predictions of failure at cracks and notches but had to be slightly modified to become applicable for the studied configurations. The criterion showed to be generally applicable to the bi-material interfaces studied herein. Sensible predictions for the tendentious strength behaviour could be made with reasonable accuracy, including the prediction of crossover from local, joint-induced failure to global failure.

    To study the micromechanical properties of a cellular solid with arbitrary topology, various models of a closed-cell foam are created on the basis of random Voronoi tessellations. The foam models are analysed using the finite element method and the effective elastic properties of the model cellular solids are determined. The calculated moduli are compared to the properties of a real reference foam and the numerical results show to be in very good agreement.

    The mechanical properties of closed-cell, low-density cellular solids are governed by the stiffnesses of the cell edges and the cell faces. Models of idealised foam models with planar cell faces, cannot account for the curved faces found on some metal and polymer foams. Finite element models of closed-cell foams were created to analyse the influence of cell face curvature on the stiffness of the foam. By determining the elastic modulus for foams with non-planar cell faces, the effect of cell face curvature could be analysed as a function of the relative density and the distribution of solid material between cell edges and faces.

    Foam models were generated from disturbed point distribution lattices and compared to models obtained from random distributions. The aim was to analyse if and how the geometry of the cells and their spatial arrangement influences the mechanical properties of a foam. The results suggest that the spatial arrangement and the geometry of the cells have significant influence on the properties of a foam. The elastic properties calculated for models from disturbed foam structures underestimated the elastic moduli of the foam, whereas models from random structures provided results which were in very good agreement with a reference foam.

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  • 124281.
    Ribeiro-Ayeh, Steven
    KTH, Superseded Departments (pre-2005), Aeronautical Engineering.
    On the strength of bi-material interfaces2002Licentiate thesis, comprehensive summary (Other scientific)
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  • 124282.
    Ribeiro-Ayeh, Steven
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    The effect of topological disorder on the mechanical properties of cellular solidsArticle in journal (Other academic)
  • 124283.
    Ribeiro-Ayeh, Steven
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Hallström, Stefan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Stochastic finite element models for the characterisation of effective mechanical properties of cellular solidsManuscript (preprint) (Other academic)
  • 124284.
    Ribeiro-Ayeh, Steven
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Hallström, Stefan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Strength prediction of beams with bi-material butt-joints2003In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 70, no 12, p. 1491-1507Article in journal (Refereed)
    Abstract [en]

    Failure of bi-material interfaces is studied with the aim to quantify the influence of the induced stress concentrations on the strength of the interfaces. The suggested approach is applied to a specimen configuration where two different materials are butt-joined to form a two-material beam. Strength predictions for different interface bias are made and verified in experiments where a polymer foam material is joined with members of either aluminium or Plexiglas.The predictions are made using a simple point-stress criterion in combination with highly accurate finite element calculations. The point-stress criterion was known from earlier work to give accurate predictions of failure at cracks and notches but had to be slightly modified to become applicable for the studied configurations. Both the strength and the cross-over from local, joint-induced failure to global failure were predicted with reasonable accuracy.

  • 124285.
    Ribeiro-Ayeh, Steven
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Hallström, Stefan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Strength prediction of bi-material interface corners on inserts in polymer foamManuscript (preprint) (Other academic)
  • 124286.
    Ribeiro-Ayeh, Steven
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Hallström, Stefan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    The influence of cell face curvature on the stiffness of cellular solidsManuscript (preprint) (Other academic)
  • 124287.
    Riber Marklund, Anders
    KTH, School of Engineering Sciences (SCI), Physics, Reactor Technology.
    Passive acoustic leak detection in energy conversion systems of sodium fast reactors2016Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Reaching the goals of Generation IV nuclear power is challenging. However, no less than six reactor concepts have been identified as capable of fulfilling the demands. Among these, the Sodium Fast Reactor (SFR), probably represents the most mature technology as about 20 SFR plants have been operated to this day.

     

    One design-specific issue of the SFR is the risk of leak and sodium-water reaction inside a steam generator. Standard monitoring is based on hydrogen detection, resulting in high sensitivity but slow response. The alternative of acoustic leak detection methods has been studied since the 1970s since they are able to respond much faster. Demonstrating low false alarm rate while detecting the fairly weak and possibly unknown acoustic signals of leaks has however proven to be difficult.

     

    Today, the CEA performs R&D, notably within the scope of the ASTRID project, with the aim of eliminating the sodium-water reaction risk. This is achieved by a Brayton cycle, using a nitrogen turbine and compact sodium-nitrogen heat exchangers. In case of a leak in this system, the low solubility of nitrogen in sodium and the high pressure in the tertiary circuit would increase the secondary pressure, locally deteriorate performance and possibly result in harmful hydrodynamic effects. Together with the risks of a potential gas leak over to the reactor, this motivates the use of leak detection also for this design.

     

    This thesis concerns passive acoustic leak detection, primarily for a SFR sodium-nitrogen heat exchanger, arguing that this method is suitable based on experiments, numerical simulations and studies on algorithms. The word “passive” here refers to a system that does not send out any signals, but rather records the noise of the plant and detects leaks as changes in this signal. The thesis covers experiments on normal operation and leak-simulating setups as well as machine-learning based detection methods intended to be of interest also for change detection in general.

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  • 124288.
    Riber Marklund, Anders
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Reactor Technology.
    Anglart, Henryk
    KTH, School of Engineering Sciences (SCI), Physics, Reactor Technology.
    Michel, Frederic
    Demonstration of an improved passive acoustic fault detection method on recordings from the Phénix steam generator operating at full power2017In: Annals of Nuclear Energy, ISSN 0306-4549, E-ISSN 1873-2100, Vol. 101, p. 1-14Article in journal (Refereed)
    Abstract [en]

    A hidden Markov model method proposed earlier for passive acoustic leak detection in sodium fast reactor systems has been improved in order to clarify how to set all free model parameters and to allow smaller amounts of training data. The method is based on training the model on known background noise only and optimizing its free model parameters by a parametric study of detection performance for synthetic noises superposed onto the same background. This means that the method is not assuming any knowledge on the noise to be detected and may be used as a general fault detection method, even if the application envisaged here is leak detection for sodium fast reactors. Using recordings of background noise as well as from argon injection tests performed at full power in the Phénix sodium fast reactor plant, it is estimated that the resulting method will detect leak-like deviations from the background noise with a detection delay of a few seconds, a false alarm rate close to 10-8 per second and at signal-to-noise ratio conditions at least corresponding to an additive signal at −10 dB. The method is one-channel, i.e. using input from one single acoustic sensor only.

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  • 124289.
    Riber Marklund, Anders
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Reactor Technology.
    Dufek, Jan
    KTH, School of Engineering Sciences (SCI), Physics, Reactor Technology.
    Development and comparison of spectral methods for passive acoustic anomaly detection in nuclear power plants2014In: Applied Acoustics, ISSN 0003-682X, E-ISSN 1872-910X, Vol. 83, p. 100-107Article in journal (Refereed)
    Abstract [en]

    We have developed spectral signal processing methods for passive acoustic anomaly detection in nuclear power plants. Furthermore, we compared the developed and existing methods by applying them to stationary sounds recorded in a controlled environment. Our new methods show significant improvement, in particular concerning robustness against false alarms. The results also demonstrate that clear detection of a given sound at a given signal-to-noise ratio is highly dependent on the distribution of characteristic frequency content in the spectrum in relation to the background noise and the spectral uncertainty. Since the frequency monitoring principle used here is quite rigid, we stress the need for research on more flexible methods, also taking into account differences between experiments and real reactor systems.

  • 124290.
    Riber Marklund, Anders
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Reactor Technology. Commisariat Energie Atom & Energies Alternat CEA, France.
    Kishore, S.
    Prakash, V.
    Rajan, K. K.
    Michel, F.
    Passive acoustic leak detection for sodium fast reactors using hidden Markov models2016In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578Article in journal (Refereed)
    Abstract [en]

    Acoustic leak detection for steam generators of sodium fast reactors have been an active research topic since the early 1970s and several methods have been tested over the years. Inspired by its success in the field of automatic speech recognition, we here apply hidden Markov models (HMM) in combination with Gaussian mixture models (GMM) to the problem. To achieve this, we propose a new feature calculation scheme, based on the temporal evolution of the power spectral density (PSD) of the signal. Using acoustic signals recorded during steam/water injection experiments done at the Indira Gandhi Centre for Atomic Research (IGCAR), the proposed method is tested. We perform parametric studies on the HMM+GMM model size and demonstrate that the proposed method a) performs well without a priori knowledge of injection noise, b) can incorporate several noise models and c) has an output distribution that simplifies false alarm rate control.

  • 124291.
    Riber Marklund, Anders
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Reactor Technology. CEA CAD/DEN/DTN/STCP/LIET, France.
    Michel, F.
    Application of a new passive acoustic leak detection approach to recordings from the Dounreay prototype fast reactor2015In: Annals of Nuclear Energy, ISSN 0306-4549, E-ISSN 1873-2100, Vol. 85, p. 175-182Article in journal (Refereed)
    Abstract [en]

    A new approach for passive acoustic leak detection in sodium fast reactors without using a priori knowledge on the leak noise is introduced. The new approach is tested on recordings of argon and water injections from the Dounreay prototype fast reactor under digital mixing with two types of additional noise. It is estimated that the new approach is able to detect injection of argon into sodium in a stable background noise at signal to noise ratios between -9 and -17 dB with a low false alarm rate and with few free parameters in the signal processing. For detection of water into sodium injection the corresponding signal to noise ratios range from -9 to -18 dB.

  • 124292.
    Ribera, Carlos
    KTH, School of Information and Communication Technology (ICT).
    Energy Efficiency in IP over WDM Networks2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the last decade, energy efficiency in backbone networks has become an important problem due to the significant growth in the Internet traffic. A very promising solution to solve this problem in Internet Protocol (IP) over Wavelength Division Multiplexing (WDM) networks is the Virtual Topology Adaptation approach, which permits adapting network resources by following a dynamic daily traffic profile. In this approach, virtual topology in the WDM layer adapts to the changes in the IP traffic, however, IP layer routing is following the conventional shortest path routing strategy being unaware of the lower layer adaptation. This thesis study aims to analyze the possibilities of power savings in WDM and IP layers in coordination and proposes multi-layer approaches for energy-efficient IP over WDM networks.

    Energy-efficient algorithms on a realistic scenario are considered where commercially available routers and their power consumption parameters are taken into account. Among these IP router systems, power consumption of single and multi-shelf systems are analyzed. Multi shelf system can accommodate multiple chassis in a rack while in the single shelf system only one chassis is employed.

    For networks with single-shelf routers, we propose an energy-aware IP traffic routing strategy in coordination with a virtual topology adaptation approach to save energy by following a dynamic daily traffic profile. Energy-efficient IP routing strategy offloads the traffic from the network resources running in extreme load levels resulting in stabilization in the virtual topology and improvement in energy-efficiency. It is shown that using this approach a considerable amount of energy is saved compared to the case of virtual topology adaptation without the IP layer involvement.

    Power consumption in networks composed of multi-shelf routers is studied and three different strategies for energy efficiency are proposed: one in the WDM layer, an Energy and Chassis-Aware Virtual Topology Adaptation (ECA-VTA), another in the IP layer, the Energy and Chassis-Aware IP Routing (ECA-IP), and a multi-layer strategy that combines ECA-VTA and ECA-IP (ECA-IP-VTA). Joint optimization of IP&WDM layers significantly reduces power consumption and number of changes in the virtual-topology compared with single-layer approach.

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  • 124293.
    Ribera, Carlos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Cavdar, Cicek
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Yayimli, Ayşegül Gençata
    Istanbul Technical University, Department of Computer Engineering.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Multi layer energy-efficiency in IP over WDM networks2012In: 2012 Asia Communications And Photonics Conference (ACP), IEEE , 2012, Vol. 28, no 14, p. ATh2D.7-Conference paper (Refereed)
    Abstract [en]

    We propose an energy-aware Internet Protocol (IP) traffic routing strategy together with a virtual topology adaptation approach to save energy in the IP over WDM networks by following a dynamic daily traffic profile.

  • 124294.
    Riberio Da Silva, Elias Hans Dener
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.). Pontifical Catholic Univeristy of Parana, Imaculada Conceição, 1155, 80215-901, Curitiba, Brazil.
    Angelis, Jannis
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Management & Technology. Research Institute of Industrial Economics, Grevgatan 34, SE-10215, Stockholm, Sweden.
    Pinheiro de Lima, Edson
    Pontifical Catholic Univeristy of Parana, Imaculada Conceição, 1155, 80215-901, Curitiba, Brazil ; Federal University of Technology - Parana, Pato Branco, Brazil.
    In pursuit of Digital Manufacturing2019In: Procedia Manufacturing, ISSN 2351-9789, Vol. 28, p. 63-69Article in journal (Refereed)
    Abstract [en]

    Companies are adopting several new technologies that form the pillars of Industry 4.0 production framework, of which Digital Manufacturing (DM) stands out by combining conventional manufacturing technologies with digital techniques. These are used to assist in the design and analysis of the product and manufacturing processes. The adoption of digital manufacturing is partly about technological change, but it also entails significant organizational issues, which often are overlooked by managers. The purpose of this study is to identify the key factors that enable or prevent DM implementation, considering the production paradigm of Industry 4.0. Based on a literature review that identified a preliminary list of key factors, the appropriateness of these factors is empirically tested and refined in a two-fold approach: an in-depth pilot case in a multinational automotive company that is adopting DM technologies, and a survey of 113 users, managers, implementers and researchers working on digital manufacturing and Industry 4.0. The study identified 24 key factors to be considered when firms implement DM. These are categorized into technical, organizational, project based and external factors. The findings also indicate how each factor should be considered, and that they cannot be generalized due to cultural differences inherent to each individual company. As such, this research contributes to the current research debate by identifying the critical factors to be considered when conceiving and applying models for planning and executing DM implementation.

  • 124295.
    Ribet, Federico
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Integrated microsystems for continuous glucose monitoring, interstitial fluid sampling and digital microfluidics2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Interdisciplinary research between medicine and microsystem engineering creates new possibilities to improve the quality of life of patients or to further enhance the performance of already existing devices. In particular, microsystems show great potential for the realization of biosensors and sampling devices to monitor bioanalytes with minimal patient discomfort. Microneedles offer a minimally invasive and painless solution to penetrate the epidermis and provide access to dermal interstitial fluid (ISF), to monitor various substances without the need for more invasive and painful extraction of blood. Diabetes, for example, requires continuous monitoring of the glucose levels in the body (CGM) to avoid complications. Although glucose is traditionally measured in finger-prick blood, CGM, which is performed in ISF, has been proven to be beneficial in the management of the disease. However, current commercial solutions are still relatively large and invasive. In this work, an electrochemical glucose sensor 50 times smaller than competing commercial devices was combined with a hollow silicon microneedle and shown to be able to measure glucose levels in the dermis in vivo. A scalable manufacturing method for the assembly of the two separately fabricated components and their electrical interconnection was also demonstrated. At the same time, a single data point may be sufficient in other situations, such as when only the presence of a certain biomarker or drug needs to be assessed. Although continuous monitoring is not required in these cases, the patient would still benefit by avoiding blood extraction. However, there are no simple devices currently available to reliably sample and store ISF. A painless microneedle-based sampling device designed to extract 1 μL of ISF from the dermis was realized. The sampled liquid is metered and stored in a paper matrix embedded in a microfluidic chip. The sample could then be analyzed using state-of-the-art tools, such as mass spectrometry.On the other hand, device miniaturization also creates issues for sensor performance. In certain types of electrochemical gas sensors, such as nitric oxide sensors used for asthma monitoring, the reduced size results in a shorter device lifetime. These sensors typically operate with a liquid electrolyte, subject to evaporation, and their long-term stability tends to be proportional to the electrode size. To address this issue, a gas diffusion and evaporation controlling platform to be integrated with this type of sensors was proposed. Such a platform opens or seals the sensing compartment on demand, potentially enabling sensor recalibration and evaporation reduction when the sensor is not in use. The device is based on electrowetting-on-dielectric actuation of low-vapor-pressure ionic liquid microdroplets on partially perforated membranes. The platform was then modified to create a zero-insertion loss and broad-band-operation laser shutter.

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  • 124296.
    Ribet, Federico
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Bendes, Annika
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Affinity Proteomics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Fredolini, Claudia
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Affinity Proteomics.
    Dobielewski, Mikolaj
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Böttcher, Michael
    MVZ Medizinische Labor Dessau Kassel GmbH D‐06847 Dessau‐Rosslau Germany.
    Beck, Olof
    Department of Clinical Neuroscience Karolinska Institute Stockholm 17177 Sweden.
    Schwenk, Jochen M.
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Affinity Proteomics.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Microneedle Patch for Painless Intradermal Collection of Interstitial Fluid Enabling Multianalyte Measurement of Small Molecules, SARS‐CoV‐2 Antibodies, and Protein Profiling2023In: Advanced Healthcare Materials, ISSN 2192-2640, E-ISSN 2192-2659, Vol. 12, no 13Article in journal (Refereed)
    Abstract [en]

    Blood sampling is a common practice to monitor health, but it entails a series of drawbacks for patients including pain and discomfort. Thus, there is a demand for more convenient ways to obtain samples. Modern analytical techniques enable monitoring of multiple bioanalytes in smaller samples, opening possibilities for new matrices, and microsampling technologies to be adopted. Interstitial fluid (ISF) is an attractive alternative matrix that shows good correlation with plasma concentration dynamics for several analytes and can be sampled in a minimally invasive and painless manner from the skin at the point-of-care. However, there is currently a lack of sampling devices compatible with clinical translation. Here, to tackle state-of-the-art limitations, a cost-effective and compact single-microneedle-based device designed to painlessly collect precisely 1.1 µL of dermal ISF within minutes is presented. The fluid is volume-metered, dried, and stably stored into analytical-grade paper within the microfluidic device. The obtained sample can be mailed to a laboratory, quantitatively analyzed, and provide molecular insights comparable to blood testing. In a human study, the possibility to monitor various classes of molecular analytes is demonstrated in ISF microsamples, including caffeine, hundreds of proteins, and SARS-CoV-2 antibodies, some being detected in ISF for the first time.

  • 124297.
    Ribet, Federico
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    De Luca, Eleonora
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics.
    Ottonello Briano, Floria
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics.
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Zero-insertion-loss optical shutter based on electrowetting-on-dielectric actuation of opaque ionic liquid microdroplets2019In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 115, no 7, article id 073502Article in journal (Refereed)
    Abstract [en]

    This article reports a broad-band optical shutter based on microdroplet actuation with zero optical insertion loss in the open state. These features are achieved by electrowetting-on-dielectric (EWOD) actuation of opaque ionic liquid microdroplets. The negligible vapor pressure of ionic liquids allows the device to robustly operate in open air, unlike previously proposed EWOD-based systems in which the light crosses several attenuating and reflective layers, preventing broad-band operation and creating insertion losses > 14%. The presented device provides an attenuation of 78dB in the closed state and a transmission of >99.99999% in the open state and can operate in the visible and mid-infrared wavelength range. Moreover, the switch can sustain larger incoming laser powers (5 mW continuous exposure or up to 3h of continuous exposure at similar to 100mW) compared to the values reported for other state-of-the-art EWOD-based shutters. Additionally, the proposed device is compact, operates with low voltage (<25V peak voltage), and features zero static power consumption.

  • 124298.
    Ribet, Federico
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    De Luca, Eleonora
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Ottonello Briano, Floria
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Zero-Loss Optical Switch Based on Ionic Liquid Microdroplet Ewod Actuation2019In: 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems and Eurosensors XXXIII, TRANSDUCERS 2019 and EUROSENSORS XXXIII, Institute of Electrical and Electronics Engineers (IEEE), 2019, p. 2290-2293, article id 8808243Conference paper (Refereed)
    Abstract [en]

    This paper reports the first optical shutter based on electrical actuation of microdroplets featuring zero insertion loss in the open state and broad-band operation. These features are achieved by electrowetting-on-dielectric (EWOD) actuation of ionic liquid microdroplets. Due to their negligible vapor pressure, ionic liquids allow the switch to robustly operate in air, unlike previously proposed systems in which the light had to cross several attenuating and refractive layers. Moreover, this solution enables operation in a much wider wavelength range, e.g. in the infrared spectrum where glass has strong absorption. Additionally, the proposed device requires lower voltage to operate (25 V) and features zero static power consumption.

  • 124299.
    Ribet, Federico
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    De Pietro, Luca
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Gas diffusion and evaporation control using EWOD actuation of ionic liquid microdroplets for gas sensing applications2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 267, p. 647-654Article in journal (Refereed)
    Abstract [en]

    The lifetime of electrochemical gas sensors suffers from electrolyte evaporation and from the impracticality to perform recalibration. To tackle these issues, a prototype of a microfabricated gas diffusion controlling system, based on coplanar electrowetting-on-dielectric (EWOD) actuation of ionic liquid microdroplets, is presented. The system is designed to be integrated with electrochemical gas sensors to allow on-demand sealing of the sensing chamber from the environment. The MEMS device can be electrically toggled between an open and a closed state, in which the microdroplets are used to cover or uncover the openings of a perforated membrane connecting to the sensing compartment, respectively. This ON/OFF diffusion-blocking valve mechanism potentially allows for recalibration and for liquid electrolyte evaporation reduction when the sensor is not in use, thus extending the gas sensor lifetime. A one order of magnitude reduction of evaporation rate and a more than three orders of magnitude reduction of gas diffusion time were experimentally demonstrated. Ionic liquid movement can be performed with an applied AC voltage as low as 18 V, using super-hydrophobic cover plates to facilitate droplet motion. Furthermore, the shown ionic liquid micro-droplet manipulation provides a robust and low voltage platform for digital microfluidics, readily adaptable to serve different applications.

  • 124300.
    Ribet, Federico
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    De Pietro, Luca
    KTH.
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Ionic liquid microdroplet manipulation by electrowetting-on-dielectric for on/off diffusion control2018In: 2018 IEEE Micro Electro Mechanical Systems (MEMS), Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 1181-1184Conference paper (Refereed)
    Abstract [en]

    This article presents a proof-of-concept of a device able to control (ON/OFF) gas diffusion through a perforated membrane. The microfabricated system is based on electrowetting-on-dielectric (EWOD) actuation of ionic liquid (IL) microdroplets and can be electrically toggled from an open to a closed state, in which microdroplets cover or uncover the membrane openings, respectively. The system is designed to be integrated with liquid-electrolyte-based electrochemical gas sensors, to extend their lifetime by reducing electrolyte evaporation and allowing recalibration. The realized device was proven to limit gas diffusion and water evaporation through perforated portions of thin membranes on command.

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