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  • 1. Andre, A.
    et al.
    Norrby, Monica
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Åkermo, Malin
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, Superseded Departments (pre-2005), Aeronautical and Vehicle Engineering.
    Nilsson, S.
    Nyman, Teresia
    KTH.
    An experimental and numerical study of the effect of some manufacturing defects2013In: ICCM International Conferences on Composite Materials, International Committee on Composite Materials , 2013, p. 4105-4112Conference paper (Refereed)
    Abstract [en]

    During the manufacturing process of composite structural parts, layer of fabrics or unidirectional prepreg may have to be cut in order to fulfil production requirements. From a general mechanical point of view, cutting fibres in a composite part has a large negative impact on the mechanical properties. However, such interventions are necessary in particular cases, for example due to draping of complex geometries. A rather extensive test program was launched to investigate the effects of defects that typically could arise during manufacturing. The overall purpose of the test program was to determine knock-down factors on strength for typical manufacturing defects that occasionally arise and sometimes are hard to avoid in production: cuts/gaps and fibre angle deviations. Four types of specimens were tested, reference, intersection of cuts in adjacent layers combined with a bolt hole, cut in a zero degree ply combined with a bolt hole and specimens with misaligned fibres. The specimens with misaligned fibres were tested with three different fibre angles. In addition to the experimental procedure, FE-analyses utilising cohesive elements were conducted, and after mechanical tests, Non Destructive Investigation (NDI) and fractographic investigations were performed. An excellent correlation between analyses and experiments were obtained. 

  • 2. André, Alain
    et al.
    Norrby, Monica
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Åkermo, Malin
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Nilsson, Sören
    Nyman, Tonny
    An Experimental And Numerical Study Of The Effect Of Some Manufacturing Defects2013In: Proceedings of the 19th International conference on composite materials, ICCM-19, 2013Conference paper (Refereed)
    Abstract [en]

    Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

  • 3.
    Ansari, Farhan
    et al.
    Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA..
    Ding, Yichuan
    Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA..
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Dauskardt, Reinhold H.
    Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA..
    Toward Sustainable Multifunctional Coatings Containing Nanocellulose in a Hybrid Glass Matrix2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 6, p. 5495-5503Article in journal (Refereed)
    Abstract [en]

    We report on a sustainable route to protective nanocomposite coatings, where one of the components, nanocellulose fibrils, is derived from trees and the glass matrix is an inexpensive sol-gel organic-inorganic hybrid of zirconium alkoxide and an epoxy-functionalized silane. The hydrophilic nature of the colloidal nanocellulose fibrils is exploited to obtain a homogeneous one-pot suspension of the nanocellulose in the aqueous sol-gel matrix precursors solution. The mixture is then sprayed to form nano composite coatings of a well-dispersed, random in-plane nano cellulose fibril network in a continuous organic inorganic glass matrix phase. The nanocellulose incorporation in the sol-gel matrix resulted in nanostructured composites with marked effects on salient coating properties including optical transmittance, hardness, fracture energy, and water contact angle. The particular role of the nanocellulose fibrils on coating fracture properties, important for coating reliability, was analyzed and discussed in terms of fibril morphology, molecular matrix, and nanocellulose/matrix interactions.

  • 4. Badia, J. D.
    et al.
    Reig-Rodrigo, P.
    Teruel-Juanes, R.
    Kittikorn, Thorsak
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Prince of Songkla University, Thailand.
    Strömberg, Emma
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Ribes-Greus, A.
    Effect of sisal and hydrothermal ageing on the dielectric behaviour of polylactide/sisal biocomposites2017In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 149, p. 1-10Article in journal (Refereed)
    Abstract [en]

    The dielectric properties of virgin polylactide (PLA) and its reinforced composites with different weight amounts of sisal fibres were assessed at broad temperature (from −130 °C to 130 °C) and frequency ranges (from 10−2–107 Hz), before and after being subjected to accelerated hydrothermal ageing. The synergetic effects of both the loading of sisal and hydrothermal ageing were analysed by means of dielectric relaxation spectra. The relaxation time functions were evaluated by the Havriliak-Negami model, substracting the ohmic contribution of conductivity. The intramolecular and intermolecular relaxations were respectively analysed by means of Arrhenius and Vogel-Fulcher-Tammann-Hesse thermal activation models. The addition of fibre increased the number of hydrogen bonds, which incremented the dielectric permittivity and mainly hindered the non-cooperative relaxations of the biocomposites by increasing the activation energy. Hydrothermal ageing enhanced the formation of the crystalline phase at the so-called transcrystalline region along sisal. This fact hindered the movement of the amorphous PLA fraction, and consequently decreased the dielectric permittivity and increased the dynamic fragility.

  • 5.
    Berglund, Lars A.
    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.
    Peijs, Ton
    Cellulose Biocomposites: From Bulk Moldings to Nanostructured Systems2010In: MRS bulletin, ISSN 0883-7694, E-ISSN 1938-1425, Vol. 35, no 3, p. 201-207Article in journal (Refereed)
    Abstract [en]

    Cellulose biocomposites are widely used in industry as a low-cost engineering material with plant fiber reinforcement. However, chemical and microstructural heterogeneity causes low strength, low strain-to-failure, high moisture sensitivity, and odor and discoloration problems. Efforts toward improved performance through fiber orientation control, increased fiber lengths, and biopolymer use are reviewed. Interfacial strength control and moisture sensitivity are remaining challenges. As an attractive alternative reinforcement, high-quality cellulose nanofibers obtained by wood pulp fiber disintegration can be prepared at low cost. These nanofibers have high length/diameter ratios, diameters in the 5-15 nm range, and intrinsically superior physical properties. Wood cellulose nanofibers are interesting as an alternative reinforcement to more expensive nanoparticles, such as carbon nanotubes. Nanopaper and polymer matrix nanocomposites based on cellulose nanofiber networks show high strength, high work-of-fracture, low moisture adsorption, low thermal expansion, high thermal stability, high thermal conductivity, exceptional barrier properties, and high optical transparency. The favorable mechanical performance of bioinspired foams and low-density aerogels is reviewed. Future applications of cellulose biocomposites will be extended from the high-volume/low-cost end toward high-tech applications, where cellulose properties are fully exploited in nanostructured materials.

  • 6.
    Berglund, Lars
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Burgert, Ingo
    Swiss Fed Inst Technol, Inst Bldg Mat, Stefano Franscini Pl 3, CH-8093 Zurich, Switzerland.;EMPA Swiss Fed Labs Mat Testing & Res, Appl Wood Res Lab, CH-8600 Dubendorf, Switzerland..
    Bioinspired Wood Nanotechnology for Functional Materials2018In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 30, no 19, article id 1704285Article in journal (Refereed)
    Abstract [en]

    It is a challenging task to realize the vision of hierarchically structured nanomaterials for large-scale applications. Herein, the biomaterial wood as a large-scale biotemplate for functionalization at multiple scales is discussed, to provide an increased property range to this renewable and CO2-storing bioresource, which is available at low cost and in large quantities. The Progress Report reviews the emerging field of functional wood materials in view of the specific features of the structural template and novel nanotechnological approaches for the development of wood-polymer composites and wood-mineral hybrids for advanced property profiles and new functions.

  • 7.
    Besharat, Zahra
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Wakeham, Deborah
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Johnson, C. Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Rutland, Mark W.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Mixed monolayers of alkane thiols with polar terminal group on gold: Investigation of structure dependent surface properties2016In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 484, no 279, p. 279-290, article id j.jcis.2016.08.053Article in journal (Refereed)
    Abstract [en]

    Adsorption of thiols with cationic or anionic terminal group on gold has been studied from mixed solutions of 11-Amino-1-undecanethiol (AUT) and 3-Mercaptopropionic acid (MPA) using Quartz Crystal Microbalance with Dissipation (QCM-D), X-ray Photoelectron Spectroscopy (XPS), atomic force microscopy (AFM) and contact angles. The goal is to probe the nature of such layers, and the additivity or otherwise of the pH responsiveness, with a view to evaluate their suitability as smart materials. For each of the two pure (unmixed) cases, ordered molecular monolayers are formed with sulfur binding to gold and the alkane chain pointing out from the surface as expected. Adsorption from the thiol mixtures, however, leads to a more complex behaviour. The surface concentration of thiols from the mixtures, as determined by QCM-D, is considerably lower than for the pure cases and it reaches a minimum at a 3:1 MPA/AUT relative concentration in the solution. The XPS results confirm a reduction in adsorbed amount in mixtures with the lowest overall intensity for the 3:1 ratio. Monolayers formed from mixtures display a wettability which is much lower and less pH sensitive. Collectively these results confirm that for adsorption from mixed systems, the configuration is completely different. Complex formation in the mixed solutions leads to the adsorption of molecules parallel to the surface in an axially in-plane configuration. This parallel layer of thiols is mechanically relatively robust to nano-shaving based on AFM measurements. These results will have a significant impact on the design of biomimetic surface coatings particularly when mixtures of oppositely charged molecules are present on the surface, as is commonly the case in biological, proteinaceous surfaces (e.g. hair and skin).

  • 8.
    Bhagwat, Ameeya
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. UM-DAE Centre for Excellence in Basic Sciences, Mumbai, India.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Consistent description of the cluster-decay phenomenon in transactinide nuclei2015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 4Article in journal (Refereed)
    Abstract [en]

    Systematic investigation of the known even-even transactinide cluster emitters has been carried out by considering the cluster as a point particle and using the exact quantum mechanical treatment of the decay process. It is shown that the cluster decay phenomenon can be described reasonably well using a simple Woods-Saxon mean field. Sensitivity of the half-lives on various aspects of the mean field has been investigated in detail.

  • 9. Borst, Sem
    et al.
    Proutiere, Alexandre
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Shah, Devavrat
    Special Issue on Recent Trends in the Mathematics of Wireless Communication Networks: Algorithms, Models and Methods-Part 1 Introduction2012In: Queueing systems, ISSN 0257-0130, E-ISSN 1572-9443, Vol. 72, no 1-2, p. 1-3Article in journal (Other academic)
  • 10.
    Bryne, Lars Elof
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Lausamaa, J.
    Ernstsson, M.
    Englund, Finn
    Wålinder, Magnus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Söderström, Ove
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    UV-laser irradiated wood: Some aspects on micromorphology, wettability, surface composition and liquid permeability2008In: Proceedings of the 4th meeting of the Nordic-Baltic network in wood material science and engineering (WSE), 2008, p. 75-82Conference paper (Refereed)
    Abstract [en]

    Many wood products used as building or construction materials involve a combination of the wood material with polymers, such as adhesives, coatings, preservatives and binders in composites. Combinations of wood and polymers in outdoor exposure, however, in general have poor long-term durability. A major cause of the unsatisfactory durability can be related to the high hygroscopicity of wood and the great difference in hygro-thermal properties between the components, resulting in wood-polymer de-bonding. In addition, mechanical processing (e.g. sawing, sanding and planning) of wood in general forms a weak boundary layer of loose and crushed wood cells in the surface which also may interfere with the wood-polymer bonding. The main objective of this work was to study ultra violet (EV), or excimer, laser irradiation on wood as a means to remove, by ablation, the outer deformed layer from a wood substrate. Effects of the UV-laser treatment on wetting and liquid permeability characteristics were studied by Wilhelmy plate experiments, and effects on the wood surface chemistry were studied by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). The micromorphology of wood was studied by low vacuum-scanning electron microscopy (LV-SEM). The pre-treatment of wood substrates by UV-laser ablation resulted in a notable changes in surface micromorphology, liquid permeability, wettability and surface chemistry characteristics.

  • 11. Budiman, B. A.
    et al.
    Juangsa, F. B.
    Aziz, M.
    Nurprasetio, I. P.
    Zaini, Ilman Nuran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Experimental verification of interfacial strength effect on the mechanical properties of carbon fiber-epoxy composite2017In: International Journal on Advanced Science, Engineering and Information Technology, ISSN 2088-5334, E-ISSN 2460-6952, Vol. 7, no 6, p. 2226-2231Article in journal (Refereed)
    Abstract [en]

    The effects of carbon fiber-epoxy interfacial strength on the mechanical properties of the corresponding fiber-matrix composites are experimentally demonstrated in this work. Two composites containing different carbon fibers were tested: as-received fibers and fibers soaked in acetone to remove adhesive on their surfaces. The fiber surfaces were first characterized by scanning electron microscopy and time-of-flight secondary-ion mass spectrometry to verify removal of the adhesive. Further, single-fiber fragmentation tests were conducted to evaluate the fiber strength and the interfacial strength. The mechanical properties of the composites were evaluated via tensile testing under longitudinal and transverse loadings. The results show that interfacial strength does not decrease the mechanical properties of the composites under longitudinal loading. In contrast, under transverse loading, the interfacial strength significantly decreases the mechanical properties, specifically the ultimate tensile strength and toughness of the composites.

  • 12. Budiman, B. A.
    et al.
    Juangsa, F. B.
    Aziz, M.
    Nurprasetio, I. P.
    Zaini, Ilman Nuran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Experimental verification of interfacial strength effect on the mechanical properties of carbon fiber-epoxy composite2017In: International Journal on Advanced Science, Engineering and Information Technology, ISSN 2088-5334, E-ISSN 2460-6952, Vol. 7, no 6, p. 2226-2231Article in journal (Refereed)
    Abstract [en]

    The effects of carbon fiber-epoxy interfacial strength on the mechanical properties of the corresponding fiber-matrix composites are experimentally demonstrated in this work. Two composites containing different carbon fibers were tested: as-received fibers and fibers soaked in acetone to remove adhesive on their surfaces. The fiber surfaces were first characterized by scanning electron microscopy and time-of-flight secondary-ion mass spectrometry to verify removal of the adhesive. Further, single-fiber fragmentation tests were conducted to evaluate the fiber strength and the interfacial strength. The mechanical properties of the composites were evaluated via tensile testing under longitudinal and transverse loadings. The results show that interfacial strength does not decrease the mechanical properties of the composites under longitudinal loading. In contrast, under transverse loading, the interfacial strength significantly decreases the mechanical properties, specifically the ultimate tensile strength and toughness of the composites.

  • 13.
    Bull, Peter Hoaas
    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.
    Curved sandwich beams with face-core debond subjected to bending moment2004In: Journal of Sandwich Structures and Materials, ISSN 1099-6362, E-ISSN 1530-7972, Vol. 6, no 2, p. 115-127Article in journal (Refereed)
    Abstract [en]

    Curved sandwich beams subjected to opening bending moment are studied. Face-core debonds of varying size are introduced at the compressively loaded face sheet and the structural integrity is investigated. Analytical and finite element models are compared in order to identify the governing failure modes of the beams. A simple expression is presented as a tool for getting a quick estimate of the severity of an interface crack in a curved sandwich beam. Five different configurations of beams are tested experimentally in a custom made bending rig.

  • 14.
    Bull, Peter Hoaas
    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.
    High-velocity and quasi-static impact of large sandwich panels2004In: Journal of Sandwich Structures and Materials, ISSN 1099-6362, E-ISSN 1530-7972, Vol. 6, no 2, p. 97-113Article in journal (Refereed)
    Abstract [en]

    An investigation of the response of sandwich structures subjected to impact velocities of virtually 0 m/s and approximately 1000 m/s is conducted. The higher velocity exceeds both the longitudinal and the transverse wave propagation velocities of the core material in the sandwich panels. The objective is to investigate the possibility to simulate the damage from ballistic impact of sandwich panels through quasi-static experiments. Panels are impacted using a 40 mm Bofors AA gun and, using a similar projectile, other panels are indented quasi-statically. Energy absorption is measured in both test series. After impact, the panels are tested in in-plane compression together with one undamaged panel for reference. Residual strength of impacted panels is analyzed by finite element analysis. It is shown that the damage from high-velocity impact is limited, and it is possible to regain most of the undamaged strength by repair.

  • 15.
    Burman, Magnus
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Composites in ships2010In: 1st conference on Service vessels for offshore wind park, 2010Conference paper (Other academic)
  • 16.
    Burman, Magnus
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    Residual Shear Strength of Polymeric Foams after Fatigue Testing2003In: 6:th International Conference on Sandwich Structures (ICSS-6), / [ed] Vinson, Rajapakse and Carlsson, New York: CRC Press , 2003, p. 522-529Conference paper (Other academic)
  • 17.
    Burman, Magnus
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Sandwich Materials in Buildings2005In: The 16th SICOMP Conference on Manufacturing and Design of Composites, 2005Conference paper (Other academic)
  • 18.
    Burman, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Colombo, C.
    Vergani, L.
    Static and fatigue characterisation of new basalt fibre reinforced composites2011In: 16th International Conference on Composite Structures, ICCS 16 / [ed] prof Antonio Ferreria, 2011Conference paper (Other academic)
  • 19.
    Burman, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Colombo, C.
    Vergani, L.
    Static and fatigue characterisation of new basalt fibre reinforced composites2012In: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 94, no 3, p. 165-1174Article in journal (Refereed)
    Abstract [en]

    Basalt reinforced composites are recently developed materials. These mineral amorphousfibres are a valid alternative to carbon fibres for their lower cost, and to glass fibres for their strength.In order to use basalt reinforced composites for structural applications, it is necessary to perform amechanical characterization. With this aim in the present work experimental results of several staticand fatigue tests are described. Two polymeric matrices are taken into account, vinylester and epoxy,to assess their influence on the evaluated parameters. In parallel to these mechanical tests, also thethermal answer of the specimens to mechanical loads is evaluated by means of thermography. Thisexperimental technique allows defining the composite local heating during the application ofmechanical loads and its behaviour in details. Final discussion on obtained results is proposedfocussing the attention on basalt fibre composite behaviour, and comparing mechanical properties ofBFRP with other composite materials in glass and carbon fibres.

  • 20.
    Burman, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Fernades, A. A.
    Ferreria, A.
    Cirrone, G.
    Adams, R.
    Araujo, F.
    Scamuzzi, M.
    Ruiz, J.
    Fernandes, F.
    Vicente, T.
    Salomon, O.
    Ziegmann, G.
    Mauri, U.
    Vergani, L.
    LITEBUS - Modular Lightweight Sandwich Bus Concept2008In: Transport Research Arena - TRA 2008, 2008Conference paper (Other academic)
  • 21.
    Burman, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Hedlund Åström, Anna
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Lingg, B.
    Villinger, S.
    Enlund, H.
    Hellbratt, S-E
    Cost and Energy Assessment of a High Speed Ship2008In: International Journal of Small Craft Technology, RINA - Part B, ISSN 1740-0694, Vol. 150, no 1, p. 1-10Article in journal (Refereed)
  • 22.
    Burman, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Kuttenkeuler, Jakob
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Naval Systems.
    Comparative Life Cycle Assessment (LCA) of the Hull of a High Speed Craft2011In: 16th International Conference on Composite Structures / [ed] Prof Antonio Ferreria, 2011Conference paper (Other academic)
  • 23. Burman, Magnus
    et al.
    Lingg, B.
    Villinger, S.
    Enlund, H.
    Hedlund Åström, Anna
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Hellbratt, S-E
    Cost and energy assessment of a high speed ship2006In: Second Conference on High Performance Yacht Design, 2006Conference paper (Other academic)
    Abstract [en]

    A comparison in total life cycle costs and energy consumption for one high speed ship design with three different structural materials have been performed. The investigation considers a high speed ferry with a steel hull and an aluminium superstructure, an all aluminium concept and a ship built in sandwich material with carbon fibre faces. The different materials will affect several cost elements during the design, the production and the operation of the ship until and including its disposal. Furthermore, the material selection has an impact on the energy consumption within all stages of the ships life cycle. The assessment is made in a comparative manner. Hence, identical out fitting components, e.g. interior, instrumentation, and ventilation are left out. It is shown that the steel version causes the highest costs and energy consumption. The sandwich construction has the lowest life cycle costs while the aluminium version has the lowest energy consumption. The break-even point between the steel and the composite versions appears after 4 years (only 2 years of operation!), the break-even point between the aluminium and the composite ferry is after 12 years (10 years of operation). A sensitivity analysis with different possible scenarios, e.g. change in interest, petrol cost, maintenance cost, has been performed. All of the investigated scenarios identify the composite version to have the lowest life cycle costs. This paper summarises an original work carried out as a master of science work as given in [1-2].

  • 24.
    Burman, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Neves, P.
    Uni of Porto.
    Grimaldi, R.
    INSIA.
    Niemeyer, S.
    Univerity of Claustahl.
    Salomon, O.
    CIMNE.
    Ziegmann, G.
    Univerity of Claustahl.
    Ferreria, A.
    University of Porto.
    Fernandes, A.A.
    University of Porto.
    Bus Pillar Test Monitoring, Simulation and Validation2009In: 15th International Conference on Composite Structures, 2009Conference paper (Other academic)
  • 25.
    Cameron, Christopher John
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lind, Eleonora
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Material Property Steered Optimization of a Multifunctional Body Panel to Structural and Acoustic Constraints2009In: Proceedings of the 17th International Conference on Composite Materials, 2009Conference paper (Other academic)
    Abstract [en]

    A conventional automobile roof, including structural and interior trim components, is replaced with a multi-layer, multi-functional sandwich construction. A weight optimizationis performed to tailor the material properties of the composite face sheets and multiple foam layers to meet structural constraints and acoustic requirements.

  • 26.
    Cameron, Christopher John
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics.
    Rahmqvist, Sven
    Saab Automobile AB.
    Structural: acoustic Design of a Multi-functional Sandwich Body Panel for Automotive Applications2008In: Proceedingsof the 8th International Conference on Sandwich Structures / [ed] A. J. M. Ferreira, 2008, p. 896-907Conference paper (Other academic)
  • 27.
    Castro, Daniele Oliveira
    et al.
    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. MoRe Research Örnsköldsvik AB, Örnsköldsvik, Sweden.
    Karim, Zoheb
    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. MoRe Research Örnsköldsvik AB, Örnsköldsvik, Sweden.
    Medina, Lilian
    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.
    Häggström, J. -O
    Carosio, F.
    Svedberg, A.
    Wågberg, Lars
    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.
    Söderberg, Daniel
    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.
    Berglund, Lars A.
    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.
    The use of a pilot-scale continuous paper process for fire retardant cellulose-kaolinite nanocomposites2018In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 162, p. 215-224Article in journal (Refereed)
    Abstract [en]

    Nanostructured materials are difficult to prepare rapidly and at large scale. Melt-processed polymer-clay nanocomposites are an exception, but the clay content is typically below 5 wt%. An approach for manufacturing of microfibrillated cellulose (MFC)/kaolinite nanocomposites is here demonstrated in pilot-scale by continuous production of hybrid nanopaper structures with thickness of around 100 μm. The colloidal nature of MFC suspensions disintegrated from chemical wood fiber pulp offers the possibility to add kaolinite clay platelet particles of nanoscale thickness. For initial lab scale optimization purposes, nanocomposite processing (dewatering, small particle retention etc) and characterization (mechanical properties, density etc) were investigated using a sheet former (Rapid Köthen). This was followed by a continuous fabrication of composite paper structures using a pilot-scale web former. Nanocomposite morphology was assessed by scanning electron microscopy (SEM). Mechanical properties were measured in uniaxial tension. The fire retardancy was evaluated by cone calorimetry. Inorganic hybrid composites with high content of in-plane oriented nanocellulose, nanoclay and wood fibers were successfully produced at pilot scale. Potential applications include fire retardant paperboard for semi structural applications.

  • 28. Chen, Xiangrong
    et al.
    Murdany, Deni
    Liu, Dongming
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Andersson, Mattias
    Gubanski, Stanislaw M.
    Gedde, Ulf W.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Suwarno, S.
    AC and DC Pre-stressed Electrical Trees in LDPE and its Aluminum Oxide Nanocomposites2016In: IEEE transactions on dielectrics and electrical insulation, ISSN 1070-9878, E-ISSN 1558-4135, Vol. 23, no 3, p. 1506-1514Article in journal (Refereed)
    Abstract [en]

    Resistance of pure low density polyethylene (LDPE) and its aluminum oxide nanocomposites (up to 3.0 wt%) to degradation by electrical treeing under AC stress and DC pre-stress is analyzed. The experiments were carried out on wire-plane electrode specimens before and after exposure to thermal and DC electro-thermal ageing at 80 degrees C. The obtained results showed enhanced resistance of the nanocomposites to electrical tree inception under AC stress and the tree inception voltage (TIV) increased with nanoparticles content. It has been shown that there was an improved partial discharge (PD) resistance in the nanocomposites compared to the unfilled LDPE. The results also showed that the AC TIV in the nanocomposites consistently increased with the ageing and especially the DC electro-thermally aged specimens had about 30% higher the AC TIV as compared to the unaged material. This effect is attributed to significantly reduced mobility of charge carriers in the nanocomposites. The DC pre-stressed electrical trees generated in the investigated materials were of filamentary-branch structure and the branch channels content increases with the addition of nanoparticles. The mean tree number of the DC prestressed electrical trees decreased in the LDPE and its nanocomposites while the mean maximum tree length increased with the ageing treatments. It is postulated that material recrystallization and a very high electric field level on the wire electrode during the DC pre-stressed electrical tree test are the main reasons for the observed effects.

  • 29.
    Chiu, NingWei Justin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Recent Development in Phase Change Materials for Thermal Energy Storage2012In: BIT's 1st Annual World Congress of Advanced Materials 2012: Innovation, Cutting-Edge and Smartness / [ed] International Research Center of International Talent, Beijing China, 2012, p. 299-300Conference paper (Refereed)
    Abstract [en]

    Phase change materials (PCMs) have in the past years been in the center of research focus as an energy saving alternative. They have large potential for use in applications where intermittent energy sources are present and where shift of energy supply from user demand in time and in space is required. Examples are solar heating, night time ambient air cooling, and waste heat utilization amongst others. The materials store and release heat through change of phase from solid to liquid in endothermic process and from liquid to solid in exothermic process.

    There are currently two major axes of PCM development driven application-wise. In passive thermal energy storage (TES) systems where the predominant role of PCMs is to serve as insulating material, thermal properties of the PCMs are tailored towards low thermal conductivity so as to limit heat transfer rate. In active TES, however, the research interest has been put in ameliorating the overall thermal power output. Various methods are dispersion of highly conductive particles, impregnation of PCM in graphite matrices, and novel design of heat exchanger apparatus.

    The second research axe lies in improvement of material compatibility with the considered applications. Inorganic PCMs are characterized with subcooling effect, this means start of heat release well below the phase change temperature. While this can be used in the advantage for long term seasonal heat storage, in active cold storage systems where the working temperature range is relatively small, subcooling is to be limited in order to provide efficient thermal charge and discharge cycle. Furthermore, efforts have been put in limiting phase separation; this has a predominant role in assuring the energy storage stability for repeated charge/discharge cycles.

    This presentation will provide insights to the recent material development in the field of thermal energy storage.

  • 30. Clemons, Craig M.
    et al.
    Rowell, Roger M.
    Plackett, David
    Segerholm, Kristoffer
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Chapter 13: Wood/nonwood thermoplastic composites2012In: Handbook of wood chemistry and wood composites, second edition / [ed] Rowell Roger M., Boca Racon, FL: CRC Press, 2012, 2, p. 473-508Chapter in book (Refereed)
  • 31.
    Dev, Apurba
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Dev Choudhury, Bikash
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Abedin, Ahmad
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Fabrication of Periodic Nanostructure Assemblies by Interfacial Energy Driven Colloidal Lithography2014In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 24, no 29, p. 4577-4583Article in journal (Refereed)
    Abstract [en]

    A novel interfacial energy driven colloidal lithography technique to fabricate periodic patterns from solution-phase is presented and the feasibility and versatility of the technique is demonstrated by fabricating periodically arranged ZnO nanowire ensembles on Si substrates. The pattern fabrication method exploits different interfaces formed by sol-gel derived ZnO seed solution on a hydrophobic Si surface covered by a monolayer of colloidal silica spheres. While the hydrophobic Si surface prevents wetting by the seed solution, the wedge shaped regions surrounding the contact point between the colloidal particles and the Si substrate trap the solution due to interfacial forces. This technique allows fabrication of uniform 2D micropatterns of ZnO seed particles on the Si substrate. A hydrothermal technique is then used to grow well-defined periodic assemblies of ZnO nanowires. Tunability is demonstrated in the dimensions of the patterns by using silica spheres with different diameters. The experimental data show that the periodic ZnO nanowire assembly suppresses the total reflectivity of bare Si by more than a factor of 2 in the wavelength range 400-1300 nm. Finite-difference time-domain simulations of the wavelength-dependent reflectivity show good qualitative agreement with the experiments. The demonstrated method is also applicable for other materials synthesized by solution chemistry.

  • 32.
    Dionisi, Filippo
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. Politecnico di Milano, Italy.
    Harnden, Ross
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    A model to analyse deformations and stresses in structural batteries due to electrode expansions2017In: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 179, p. 580-589Article in journal (Refereed)
    Abstract [en]

    In order to aid design of future structural battery components an analytical model is developed for modelling volume expansions in laminated structural batteries. Volume expansions are caused by lithium ion intercalation in carbon fibre electrodes. An extended version of Classical Lamination Plate Theory (CLPT) is used to allow analysis of unbalanced and unsymmetric lay-ups. The fibre intercalation expansions are treated analogously to a thermal problem, based on experimental data, with intercalation coefficients relating the fibre capacity linearly to its expansions. The model is validated using FEM and allows the study of the magnitude of interlaminar stresses and hence the risk of delamination damage due to the electrochemically induced expansions. It also enables global laminate deformations to be studied. This allows information about favourable lay-ups and fibre orientations that minimise deformations and the risk of delamination to be obtained. Favourable configurations for application to a solid state mechanical actuator are also given.

  • 33.
    Doddapaneni, Venkatesh
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    On the polymer-based nanocomposites for electrical switching applications2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Recent research demonstrated that polymer based nanocomposites (PNCs) have been engineered in order to improve the arc interruption capability of the circuit breakers. PNCs are the combination of nano-sized inorganic nanoparticles (NPs) and polymers, opened up new developments in materials science and engineering applications. Inorganic NPs are selected based on their physical and chemical properties which could make multifunctional PNCs in order to interrupt the electrical arcs effectively. In particular, we presented the PNCs fabricated by using CuO, Fe3O4, ZnO and Au NPs in a poly (methyl methacrylate) (PMMA) matrix via in-situ polymerization method, recently developed method to avoid NPs agglomeration, leading to good spatial distribution in the polymer matrix. Thus, several samples with various wt% of NPs in PMMA matrix have been fabricated. These PNCs have been characterized in detail for the morphology of NPs, interaction between NPs and polymer matrix, and radiative/thermal energy absorption properties. In the next stage, PNCs are tested to determine their arc interruption performance and impact on the electrical arcs of current 1.6 kA generated using a specially designed test set-up. When PNCs interact with the electrical arcs, they generate ablation of chemical species towards core of the electrical arc, resulting in cooling-down the arc due to strong temperature and pressure gradient in the arc quenching domain. This thesis demonstrates for the first time that these engineered PNCs are easily processed, reproducible, and can be used to improve the arc interruption process in electrical switching applications.

  • 34.
    Doddapaneni, Venkatesh
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Gati, R.
    Toprak, Muhammet Sadaka
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Engineered PMMA-ZnO nanocomposites for improving the electric arc interruption capability in electrical switching applications: Unprecedented experimental insights2017In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 141, p. 113-119Article in journal (Refereed)
    Abstract [en]

    Polymer inorganic nanocomposites (PINCs) have been engineered for controlling the electrical arc and to improve the arc interruption capability of the electrical switching applications, like circuit breakers. Several PINCs are fabricated by formation of ZnO quantum dots (QDs) in a poly (methyl methacrylate) (PMMA) matrix via in-situ polymerization method to avoid agglomeration of QDs, leading to a good spatial distribution of QDs in the polymer matrix. These PINCs have been characterized in detail for the morphology of QDs, interaction between QDs and polymer matrix, and ultraviolet (UV) radiation absorption. ZnO QDs have been assessed to have particle diameter of 3.5 nm, and their presence in the PMMA is revealed by the unique luminescence characteristics of the QDs under UV light. The presence of ZnO QDs broadened the range of UV radiation absorption of PMMA and the absorption edge is gradually shifted from 270 nm to 338 nm with step-wise loading of ZnO QDs. The PINCs are tested to determine their reproducibility and impact on the electrical arcs of current 1.6 kA generated using a specially designed test-setup. Interaction of PINCs with the electrical arcs generates ablation of chemical species towards core of the electrical arc, resulting in increase of voltage leading to cool-down the arc temperature. This experimental study demonstrates for the first time that these PINCs are reproducible, reliable and provides superior arc interruption capability.

  • 35.
    Doddapaneni, Venkatesh
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Gati, Rudolf
    ABB Switzerland.
    Toprak, Muhammet Sadaka
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    New experimental insights for controlling the electrical arcs in electrical switching applications: a comparative study on PMMA nanocomposites of Au and ZnO2017In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050Article in journal (Other academic)
    Abstract [en]

    Polymer inorganic nanocomposites (PINCs) are developed, not only due to scientific interest but also improving theelectric arc interruption process in the electrical switching applications like circuit breakers. The novelty of this work isin integrating the current developments in PINCs into electrical switching application in order to extend the limits of thepower switching devices. Several PINCs are fabricated by using pre-synthesized Au nanoparticles (NPs) of size 2.75 ±0.4 nm and poly (methyl methacrylate) (PMMA) matrix via in-situ polymerization method. Six homogeneous PINCsamples with ultra-low wt% of Au NPs varying from 0.0003 to 0.005 wt% have been fabricated. We find that thepresence of Au NPs improved the convective heat transfer and visible optical radiation absorption of PMMA. Thefabricated PINCs are tested for their arc interruption performance and the results are compared with ZnO PINCs in ourearlier work. The results of the experiments insights demonstrate the impact of PINCs on the electrical arcs and theirpotential advantages of having PINCs for the electric arc interruption process in high power switching devices.

  • 36.
    Dyakov, Sergey
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Trinity College Dublin.
    Baldycheva, A.
    Perova, T. S.
    Li, G. V.
    Astrova, E. V.
    Gippius, N. A.
    Tikhodeev, S. G.
    Surface states in the optical spectra of two-dimensional photonic crystals with various surface terminations2012In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 86, no 11, p. 115126-1151268Article in journal (Refereed)
    Abstract [en]

    Reflection and transmission spectra of two-dimensional photonic crystal slabs, fabricated by photoelectrochemical etching of deep macropores and trenches in Si, are investigated theoretically and experimentally. It is shown that the presence of an unstructured silicon interfacial layer between the air and the photonic crystal structure can give rise to surface (Tamm) states within the TE and TM photonic stop bands. In the presence of roughness of inner surfaces of air pores, the surface states show up as dips within the stop bands in the reflection spectrum. The calculated electromagnetic near-field distribution demonstrates the vortices between the upper pores at the frequency of the surface mode. The experimental reflection and transmission spectra are in a good agreement with theoretical calculations performed by the Fourier modal method in the scattering matrix form.

  • 37.
    Dyakov, Sergey
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Trinity College Dublin.
    Perova, T. S.
    Miao, C. Q.
    Xie, Y. -H
    Cherevkov, S. A.
    Baranov, A. V.
    Influence of the buffer layer properties on the intensity of Raman scattering of graphene2013In: Journal of Raman Spectroscopy, ISSN 0377-0486, E-ISSN 1097-4555, Vol. 44, no 6, p. 803-809Article in journal (Refereed)
    Abstract [en]

    Using a model of oscillating dipoles, we simulate the intensity of the G-band in the Raman signal from structures consisting of graphene, separated by an arbitrary buffer layer from a substrate. It is found that a structure with an optimized buffer layer refractive index and thickness exhibits a Raman signal which is nearly 50 times more intense than that from the same structure with a non-optimized buffer layer. The theoretical simulations are verified by Raman measurements on structures consisting of a layer of graphene on SiO2 and Al2O3 buffer layers. The optical contrast of the single graphene layer is calculated for an arbitrary buffer layer. It was found that both the Raman intensity and optical contrast can be maximized by varying the buffer layer thickness.

  • 38.
    Dyakov, Sergey
    et al.
    Department of Electronic and Electrical Engineering, Trinity College Dublin, Ireland.
    Zhigunov, D.M.
    Hartel, A.
    Zacharias, M.
    Perova, T.S.
    Timoshenko, V.Y.
    Enhancement of photoluminescence signal from ultrathin layers with silicon nanocrystals2012In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 100, no 6, p. 061908-1-061908-4Article in journal (Refereed)
    Abstract [en]

    Using the model of oscillating dipoles, we simulated the photoluminescence intensity of a triple-layered structure where the silicon nanocrystals layer was enclosed by buffer and capping silicon dioxide layers. It was found that a structure with an optimized buffer layer thickness exhibited photoluminescence which was approximately 20 times more intense than that from the structure without a buffer layer. Theoretical simulations were verified by photoluminescence measurements for the corresponding structures with silicon nanocrystals fabricated by plasma enhanced chemical vapour deposition.

  • 39.
    Egertz, David
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Novel Safety Requirements and Crash Test Standards for Light- Weight Urban Vehicles2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In recent years the interest for smaller, cheaper and more energy efficient vehicles hasincreased significantly. These vehicles are intended to be used in urban areas, where theactual need of large heavy cars is generally minor. The travelled distance is on average lessthan 56km during a day and most often there is only one person travelling in the vehicle. Manyof the established car manufacturers have recently started to take interest into this marketsegment, but the majority of these small vehicles are still manufactured by smaller companiesat a low cost and with little or no research done on vehicle traffic safety. This may be becausethere are still no legal requirements on crash testing of this type of vehicles.This report will examine road safety for Urban Light-weight Vehicle (ULV) to find criticalcrash scenarios from which future crash testing methods for urban vehicles can be derived.The term ULV is specific to this report and is the title for all engine powered three- and fourwheeledvehicles categorized by the European Commission. Other attributes than the wheelgeometry is engine power and the vehicles unladen mass. The maximum allowed weight for athree-wheeled ULV is 1 000kg and 400kg for a four-wheeled one.By studying current crash test methods used in Europe by Euro NCAP it has beenconcluded that these tests are a good way of assessing car safety. For light-weight urbanvehicles it has been concluded that some of these tests need to be changed and that some newtest scenarios should be added when assessing road safety. The main reasons for this is linkedto that vehicle’s with a weight difference of more than 150kg cannot be compared withcurrent test methods, and that crash tests are performed with crash objects with similar orequal mass in current safety assessment programs. This correlates poorly to the trafficsituation for light-weight urban vehicles since it would most likely collide with a far heaviervehicle than itself in an accident event.To verify the actual traffic situation in urban areas, accident statistics have beenexamined closely. The research has shown that there are large differences between rural andurban areas. For instance; 66% of all severe and fatal traffic accident occurs in rural areaseven though they are less populated. Even the distribution of accident categories has showndifferent in rural and urban areas. The United Nations Economic Commission for Europe(UNECE) has defined accident categories in their database which is widely used within theEuropean Union. By comparing each accident category’s occurrence, injury and fatality rate,the most critical urban accident categories were found in the following order.

    1. Collision due to crossing or turning

    2. Vehicle and pedestrian collision

    3. Rear-end collision

    4. Single-vehicle accident

    5. Other collisions

    6. Head-on collision

    Statistics also show that of all fatally injured crash victims in urban trafficapproximately; one third is travelling by car; one third by motorcycle, moped or pedal-cycle;and one third are pedestrians. This means that unprotected road travelers correspond to twothirds of all fatal urban traffic accidents, a fact that has to be taken into account in future crashtesting of urban vehicles. With all the information gathered a total of four new crash testscenarios for light-weight urban vehicles have been presented:

    • Vehicle-to-vehicle side impact at 40km/h with a 1 300kg striking vehicle to evaluate theoccupant protection level of the light-weight vehicle.

    • Vehicle-to-motorcycle side impact at 40km/h with motorcycle rider protection evaluation.

    • Pedestrian protection assessment at 40km/h over the whole vehicle front and roof area.

    • Rigid barrier impact at 40km/h corresponding to an urban single vehicle accident with aroad side object or a collision with a heavier or similar sized vehicle.

  • 40.
    Englund, F.
    et al.
    Technical Research Institute of Sweden.
    Bryne, Lars Elof
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Ernstsson, M.
    Institute for Surface Chemistry, Stockholm, Sweden.
    Lausmaa, J.
    SP Technical Research Institute of Sweden.
    Wålinder, Magnus E. P.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Spectroscopic studies of surface chemical composition and wettability of modified wood2009In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 4, no 1-2, p. 80-85Article in journal (Refereed)
    Abstract [en]

    Recent advances in spectroscopic methods used in the surface science field may provide new valuable information about the surface chemical composition of engineering materials. Such methods, combined with wettability analyses, have been applied in the development of well-designed adhesives and coating systems for newly developed and commercially available modified wood materials. The main objective of this paper is to demonstrate and present some aspects on the application of two different state-of-the-art spectroscopic methods for surface chemical composition studies of a complex material such as modified wood. The methods are X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS), the former generating more quantitative data and the latter more qualitative data. The spectroscopic data are also combined with wettability data obtained from contact angle measurements using the Wilhelmy method. Modified wood samples were prepared from pilot plant or commercially produced acetylated, furfurylated and thermally modified wood. Effects of wood surface ageing, i.e. the time after machining, on the surface chemical composition and wettability were also studied. Results clearly indicate a hydrophobization process due to ageing of the unmodified and certain modified wood, probably mainly related to a migration and reformation of extractives in the surface. The surface composition and wettability of acetylated wood was not appreciably affected by the ageing process. Such findings could be quantified by the XPS measurements, which is further discussed and related to the different wood modification routes. ToF- SIMS is a powerful tool and complementary to XPS for identification of, for example, specific hydrophobic substances in the wood surfaces. In addition, this method provides ion images, mapping the lateral distribution of selected secondary ions signals within an analysed wood surface area.

  • 41.
    Englund, F.
    et al.
    Technical Research Institute of Sweden.
    Bryne, Lars-Elof
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Ernstsson, Marie
    Institute for Surface Chemistry, Stockholm, Sweden.
    Lausmaa, J
    SP Technical Research Institute of Sweden.
    Wålinder, M. E. P.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Some Aspects on the Determination of Surface Chemical Composition and Wettability of Modified Wood2009In: Proceedings of the Fourth European Conference on Wood Modification / [ed] F. Englund, C.A.S. Hill, H. Militz and B.K. Segerholm, Stockholm: SP Technical Research Institute of Sweden , 2009, p. 553-560Conference paper (Refereed)
  • 42.
    Eric, Jacques
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Kjell, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Behm, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Impact of the mechanical loading on the electrochemical capacity of carbon fibres for use in energy storage composite materials2011Conference paper (Other academic)
    Abstract [en]

    Reducing system mass for improvements in system performance has become a priority for future applications such as mobile phones or electric vehicles which require load bearing components and electrical energy storage devices. Structure and energy storage are usually subsystems with the highest mass contributions but energy storage components are structurally parasitic. A novel solution is a multifunctional lightweight design combining these two functions in a single material entity able to simultaneously bear mechanical loads as a carbon fiber composite component and store electrochemical energy as a lithium-ion battery.

  • 43.
    Eva, Marra
    KTH, School of Chemical Science and Engineering (CHE).
    Synthesis and Characterization of GDC-NiO Nanopowder2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A composite of Cerium Gadolinium Oxide (GDC) and Nickel Oxide (NiO) was prepared by the co-precipitation method. The synthesized powder is the precursor of Ni-GDC which is a potential anode material for a Solid Oxide Fuel Cell (SOFC). X-ray diffraction results confirm the formation of GDC and NiO, as well as the nanometric dimensions of these formed phases. Mesoporous domains and high surface area are evidenced by the results of Nitrogen physisorption. The crystallinity of the powder and its agglomerated structure are graphically shown in the images obtained by the Scanning Electron Microscopy (SEM) and Transmission Scanning Microscopy (TEM). All these results indicate that co-precipitation is a suitable method for obtaining the GDC-NiO composite.

  • 44.
    Evangelopoulos, Panagiotis
    et al.
    KTH, School of Industrial Engineering and Management (ITM).
    Arvelakis, Stylianos
    National Technical University of Athens.
    Kantarelis, Efthymios
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Experimental investigation of low temperature pyrolysis of printed circuit boards (PCBs) and printed circuit board components (PCB sockets)Manuscript (preprint) (Other academic)
    Abstract [en]

    Printed circuit boards (PCBs) are the heart of all electronics due to their compact size and the broad spectrum of applications but very challenging when their life ends. Recycling of these components is problematic since they consist of different metallic parts packed on plastic compressed cover. The present study focuses on low temperature pyrolysis of PCBs since this process can separate the organic fraction from the inorganics. The latter, enables further separation and purification of the metals which are not oxidized during mild treatment. The low Br content of the resultant char after treatment at 320 oC for 30 min indicates that it could be used as solid fuel if efficient separation from the inorganic part would be performed. Moreover, the liquids obtained by this process can be used for feedstock recycling since the results indicates that toxic bromine containing on the organic compounds has been decreased both by increasing the residence time of pyrolysis process or by increasing the temperature conditions.

  • 45.
    Fan, Liangdong
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Development and characterization of functional composite materials for advanced energy conversion technologies2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The solid oxide fuel cell (SOFC) is a potential high efficient electrochemical device for vehicles, auxiliary power units and large-scale stationary power plants combined heat and power application. The main challenges of this technology for market acceptance are associated with cost and lifetime due to the high temperature (700-1000 oC) operation and complex cell structure, i.e. the conventional membrane electrode assemblies. Therefore, it has become a top R&D goal to develop SOFCs for lower temperatures, preferably below 600 oC. To address those above problems, within the framework of this thesis, two kinds of innovative approaches are adopted. One is developing functional composite materials with desirable electrical properties at the reduced temperature, which results of the research on ceria-based composite based low temperature ceramic fuel cell (LTCFC). The other one is discovering novel energy conversion technology - Single-component/ electrolyte-free fuel cell (EFFC), in which the electrolyte layer of conventional SOFC is physically removed while this device still exhibits the fuel cell function. Thus, the focus of this thesis is then put on the characterization of materials physical and electrochemical properties for those advanced energy conversion applications. The major scientific content and contribution to this challenging field are divided into four aspects except the Introduction, Experiments and Conclusions parts. They are:

    1. Continuous developments and optimizations of advanced electrolyte materials, ceria-carbonate composite, for LTCFC. An electrolysis study has been carried out on ceria-carbonate composite based LTCFC with cheap Ni-based electrodes. Both oxygen ion and proton conductance in electrolysis mode are observed. High current outputs have been achieved at the given electrolysis voltage below 600 oC. This study also provides alternative manner for high efficient hydrogen production.
    2.  Compatible and high active electrode development for ceria-carbonate composite electrolyte based LTCFC. A symmetrical fuel cell configuration is intentionally employed. The electro-catalytic activities of novel symmetrical transition metal oxide composite electrode toward hydrogen oxidation reaction and oxygen reduction reaction have been experimentally investigated. In addition, the origin of high activity of transition metal oxide composite electrode is studied, which is believed to relate to the hydration effect of the composite oxide.
    3. A novel all-nanocomposite fuel cell (ANFC) concept proposal and feasibility demonstration. The ANFC is successfully constructed by Ni/Fe-SDC anode, SDC-carbonate electrolyte and lithiated NiO/ZnO cathode at an extremely low in-situ sintering temperature, 600 oC. The ANFC manifests excellent fuel cell performance (over 550 mWcm-2 at 600 oC) and a good short-term operation as well as thermo-cycling stability. All results demonstrated its feasibility and potential for energy conversion.
    4. Fundamental study results on breakthrough research Single-Component/Electrolyte-Free Fuel Cell (EFFC) based on above nanocomposite materials (ion and semi-conductive composite) research activities. This is also the key innovation point of this thesis. Compared with classic three-layer fuel cells, EFFC with an electrolyte layer shows a much simpler but more efficient way for energy conversion. The physical-electrical properties of composite, the effects of cell configuration and parameters on cell performance, materials composition and cell fabrication process optimization, micro electrochemical reaction process and possible working principle were systematically investigated and discussed. Besides, the EFFC, joining solar cell and fuel cell working principle, is suggested to provide a research platform for integrating multi-energy-related device and technology application, such as fuel cell, electrolysis, solar cell and micro-reactor etc.

    This thesis provides a new methodology for materials and system innovation for the fuel cell community, which is expected to accelerate the wide implementation of this high efficient and green fuel cell technology and open new horizons for other related research fields.

  • 46.
    Fang, Mei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Belova, Lyuba
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Rao, K. Venkat
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Thermal anealing effects on Ag/TiO2 thin films prepared by ink-jet printingManuscript (preprint) (Other academic)
    Abstract [en]

    The effects of heat treatment on both the phase structure and the electronic band structure were studied for Ag/TiO2 composite films prepared by inkjet printing. Ag nanoparticles can form ‘metal-bridge’ to link TiO2 particles in the mesoporous structured films and improve the transport properties of the films. The distribution of Ag in the composite films shows dependence on the annealing conditions: Ag clusters were observed at high annealing temperature (>600 °C), and they can be annihilated by a longer time annealing. Comparing with pure TiO2 films, the decreased intensity of the photoluminescence (PL) emission spectra of Ag/TiO2 composite films indicates that the doped Ag atoms could act as traps to capture electron and inhabit the recombination of electron-hole pairs. From the identifiable PL emission peaks, the band structure of the films is deduced.

  • 47.
    Fu, Qiliang
    et al.
    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.
    Yan, Min
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Jungstedt, Erik
    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.
    Yang, Xuan
    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.
    Li, Yuanyuan
    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.
    Berglund, Lars A.
    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.
    Transparent plywood as a load-bearing and luminescent biocomposite2018In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 164, p. 296-303Article in journal (Refereed)
    Abstract [en]

    Transparent wood (TW) structures in research studies were either thin and highly anisotropic or thick and isotropic but weak. Here, transparent plywood (TPW) laminates are investigated as load-bearing biocomposites with tunable mechanical and optical performances. Structure-property relationships are analyzed. The plies of TPW were laminated with controlled fiber directions and predetermined stacking sequence in order to control the directional dependence of modulus and strength, which would give improved properties in the weakest direction. Also, the angular dependent light scattering intensities were investigated and showed more uniform distribution. Luminescent TPW was prepared by incorporation of quantum dots (QDs) for potential lighting applications. TPW can be designed for large-scale use where multiaxial load-bearing performance is combined with new optical functionalities.

  • 48.
    Fu, Qilin
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology. Plasmatrix Materials AB.
    High dynamic stiffness nano-structured composites for vibration control: A Study of applications in joint interfaces and machining systems2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Vibration control requires high dynamic stiffness in mechanical structures for a reliable performance under extreme conditions. Dynamic stiffness composes the parameters of stiffness (K) and damping (η) that are usually in a trade-off relationship. This thesis study aims to break the trade-off relationship.

    After identifying the underlying mechanism of damping in composite materials and joint interfaces, this thesis studies the deposition technique and physical characteristics of nano-structured HDS (high dynamic stiffness) composite thick-layer coatings. The HDS composite were created by enlarging the internal grain boundary surface area through reduced grain size in nano scale (≤ 40 nm). The deposition process utilizes a PECVD (Plasma Enhanced Chemical Vapour Deposition) method combined with the HiPIMS (High Power Impulse Magnetron Sputtering) technology. The HDS composite exhibited significantly higher surface hardness and higher elastic modulus compared to Poly(methyl methacrylate) (PMMA), yet similar damping property. The HDS composites successfully realized vibration control of cutting tools while applied in their clamping interfaces.

    Compression preload at essential joint interfaces was found to play a major role in stability of cutting processes and a method was provided for characterizing joint interface properties directly on assembled structures. The detailed analysis of a build-up structure showed that the vibrational mode energy is shifted by varying the joint interface’s compression preload. In a build-up structure, the location shift of vibration mode’s strain energy affects the dynamic responses together with the stiffness and damping properties of joint interfaces.

    The thesis demonstrates that it is possible to achieve high stiffness and high damping simultaneously in materials and structures. Analysis of the vibrational strain energy distribution was found essential for the success of vibration control.

  • 49.
    Fu, Qilin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Lorite, Gabriela Simone
    Rashid, Md. Masud-Ur
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Selkala, Tuula
    Uusitalo, Juha
    Toth, Geza
    Kordas, Krisztian
    Österlind, Tomas
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Nicolescu, Cornel Mihai
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Suppressing tool chatter with novel multi-layered nanostructures of carbon based composite coatings2015In: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 223, p. 292-298Article in journal (Refereed)
    Abstract [en]

    Multi-layered nanostructured Cu and Cu-CNx composites synthesized by plasma-enhanced chemical vapour deposition were applied in the clamping area of a milling tool to suppress regenerative tool chatter. Scanning electron microscopy analysis showed a multi-layered nanostructure with excellent conformality, i.e. coating is not only uniform on planar surfaces but also around corners of the substrate. Cu:CuCNx nanostructured multilayers with thicknesses of approximately 0.5:1.6 mu m were obtained. With a diameter of 20 mm, the milling tool performed slotting processes at an overhang length of 120 mm. Modal analysis showed that a coating, with a thickness of approximately 300 mu m, can add sufficient damping without losing stiffness of the tool, to increase the critical stability limit by 50% or 100% depending on cutting direction.

  • 50.
    Fu, Qilin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Lundin, Daniel
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Nicolescu, Cornel Mihai
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Anti-vibration Engineering in Internal Turning Using a Carbon Nanocomposite Damping Coating Produced by PECVD Process2014In: Journal of materials engineering and performance (Print), ISSN 1059-9495, E-ISSN 1544-1024, Vol. 23, no 2, p. 506-517Article in journal (Refereed)
    Abstract [en]

    Machining dynamic stability has been enhanced through a damping coating based on a novel carbon-based nanocomposite material. The coating was synthesized using a plasma enhanced chemical vapor deposition method, and deposited on to the round-shank boring bar used for internal turning and tested during machining. Comparisons between an uncoated and a coated boring bar were carried out at 0.25 mm and 0.5 mm depth of cut using a five times length to diameter ratio overhang, which are typical conditions known to generate detrimental mechanical vibrations. From sound pressure measurement it was found that the measured absolute sound level during process could be reduced by about 90% when using the tool coated with damping layer. Surface roughness measurements of the processed workpiece showed decreased Ra values from approximately 3-6 mu m to less than 2 mu m (and in 50% of the cases < 1 mu m) when comparing an uncoated standard tool with its coated counterpart. Moreover, it was found that the addition of an anti-vibration coating did not adversely affect other tool properties, such as rigidity and modularity.

12345 1 - 50 of 215
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