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  • 1.
    Abdulla, Hind
    et al.
    Khalifa Univ Sci & Technol, Engn Syst & Management, POB 127788, Abu Dhabi, U Arab Emirates.;Khalifa Univ Sci & Technol, Adv Digital & Addit Mfg Ctr, POB 127788, Abu Dhabi, U Arab Emirates..
    An, Heungjo
    Kumoh Natl Inst Technol, Sch Ind Engn, Gumi 39177, South Korea..
    Barsoum, Imad
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. Khalifa Univ Sci & Technol, Adv Digital & Addit Mfg Ctr, POB 127788, Abu Dhabi, U Arab Emirates.;Khalifa Univ Sci & Technol, Mech Engn, POB 127788, Abu Dhabi, U Arab Emirates..
    Maalouf, Maher
    Khalifa Univ Sci & Technol, Engn Syst & Management, POB 127788, Abu Dhabi, U Arab Emirates.;Khalifa Univ Sci & Technol, Res Ctr Digital Supply Chain & Operat, POB 127788, Abu Dhabi, U Arab Emirates..
    Mathematical Modeling of Multi-Performance Metrics and Process Parameter Optimization in Laser Powder Bed Fusion2022In: Metals, ISSN 2075-4701, Vol. 12, no 12, article id 2098Article in journal (Refereed)
    Abstract [en]

    This study aims to develop mathematical models to improve multi-performance metrics, such as relative density and operating costs, in laser powder bed fusion (LPBF), also known as selective laser melting, a metallic additive manufacturing technique, by optimizing the printing process parameters. The work develops a data-driven model for relative density based on measurements and an analytical model for operating costs related to the process parameters. Optimization models are formulated to maximize relative density or minimize operating costs by determining the optimal set of process parameters, while meeting a target level of the other performance metrics (i.e., relative density or operating costs). Furthermore, new metrics are devised to test the sensitivity of the optimization solutions, which are used in a novel robust optimization model to acquire less sensitive process parameters. The sensitivity analysis examines the effect of varying some parameters on the relative density of the fabricated specimens. Samples with a relative density greater than 99% and a machine operating cost of USD 1.00 per sample can be produced, utilizing a combination of low laser power (100 W), high scan speed (444 mm/s), moderate layer thickness (0.11 mm), and large hatch distance (0.4 mm). This is the first work to investigate the relationship between the quality of the fabricated samples and operating cost in the LPBF process. The formulated robust optimization model achieved less sensitive parameter values that may be more suitable for real operations. The equations used in the models are verified via 10-fold cross-validation, and the predicted results are further verified by comparing them with the experimental data in the literature. The multi-performance optimization models and framework presented in this study can pave the way for other additive manufacturing techniques and material grades for successful industrial-level implementation.

  • 2.
    Adane, Tigist
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology. KTH.
    Nicolescu, Mihai
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Towards a Generic Framework for the Performance Evaluation of Manufacturing Strategy: An Innovative Approach2018In: Journal of Manufacturing and Materials Processing, ISSN 2504-4494, Vol. 9, no 2, p. 131-156Article in journal (Refereed)
    Abstract [en]

    To be competitive in a manufacturing environment by providing optimal performance in terms of cost-effectiveness and swiftness of system changes, there is a need for flexible production systems based on a well-defined strategy. Companies are steadily looking for methodology to evaluate, improve and update the performance of manufacturing systems for processing operations. Implementation of an adequate strategy for these systems’ flexibility requires a deep understanding of the intricate interactions between the machining process parameters and the manufacturing system’s operational parameters. This paper proposes a framework/generic model for one of the most common metal cuttingoperations—the boring process of an engine block machining system. A system dynamics modelling approach is presented for modelling the structure of machining system parameters of the boring process, key performance parameters and their intrinsic relationships. The model is based on a case study performed in a company manufacturing engine blocks for heavy vehicles. The approach could allow for performance evaluation of an engine block manufacturing system condition. The presented model enables a basis for other similar processes and industries producing discrete parts.

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    Towards a Generic Framework for the Performance Evaluation of Manufacturing Strategy: An Innovative Approach
  • 3.
    Adler, Jeanette
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Film Formation and Surface Tension Studies of Powder Coatings2005Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [en]

    In industrial use of paint systems a swift processing is crucial. Another very important issue is to improve the quality of the final coating. This report investigates the film formation process of powder coatings, specially the spreading of individual powder particles. The obtained results can be used to understand and control the film formation process. In this way the desired levelling can be achieved and thus the desired gloss or other surface characteristics that may be required. This means that the method could be used when evaluating different polymer and additive combinations that could be used to change film formation behaviour or curing time for powder coating systems to suit various substrates. It makes it possible to avoid and minimize different surface defects as orange peel or cratering in the powder coated film.

    We used a reflection optical microscope to better understand the film formation process and especially the spreading of a powder melt on surfaces with various surface energies. The obtained data were: the particle diameter, the area, area ratio and the contact angle of the powder particle as a function of time and temperature. This information can be used to derive the surface tension of any powder melt.

    In this report we evaluate the dependencies of temperature, heat rate and surface energy for powder coatings on different substrates. The method provides information that can be used to optimize the film formation of a specific powder coating/substrate combination. This method can be used to evaluate the powder spreading and levelling on different substrates from a surface tension point of view.

    We found, as expected, that the powder flows out on a hydrophilic surface and is inhibited by a hydrophobic. The increase of the area ratio on a hydrophilic surface was about five times as the initial area coverage and on a hydrophobic surface only two times the initial area coverage. The contact angle between the melted powder particle on the different surface types could be calculated. The melt surface tension could be calculated since three substrates surfaces with various surface energies were used. The melt surface tension was found to be about 18.5 mN/m.

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    FULLTEXT01
  • 4.
    Ahmed, N.
    et al.
    Khalifa Univ, Adv Digital & Addit Mfg Ctr, Abu Dhabi, U Arab Emirates..
    Barsoum, Imad
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. Khalifa Univ, Adv Digital & Addit Mfg Ctr, Abu Dhabi, U Arab Emirates.;Khalifa Univ, Dept Mech Engn, Abu Dhabi, U Arab Emirates..
    Haidemenopoulos, G.
    Univ Thessaly, Dept Mech Engn, Volos, Greece..
    Abu Al-Rub, R. K.
    Khalifa Univ, Adv Digital & Addit Mfg Ctr, Abu Dhabi, U Arab Emirates.;Khalifa Univ, Dept Mech Engn, Abu Dhabi, U Arab Emirates..
    Process parameter selection and optimization of laser powder bed fusion for 316L stainless steel: A review2022In: JOURNAL OF MANUFACTURING PROCESSES, ISSN 1526-6125, Vol. 75, p. 415-434Article, review/survey (Refereed)
    Abstract [en]

    Stainless steel 316L has been an extensively investigated metallic material for laser powder bed fusion (L-PBF) in the past few decades due to its high corrosion resistance. However, there are challenges related to producing LPBF parts with minimal defects, attaining mechanical properties comparable with traditional process and dependency on time consuming post process treatments. The selection of L-PBF process parameters is crucial to overcome these challenges. This paper reviews the research carried out on L-PBF process parameter optimization for fabrication of 316L steel components for maximizing part densifications and attaining desired microstructure morphologies in parts. A brief work on numerical simulation approach for process parameter optimization for high densifications is also included in this paper.

  • 5.
    Aldén, R.
    et al.
    SWERIM, Kista, Sweden.
    Barsoum, Zuheir
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Vouristo, T.
    SWERIM, Kista, Sweden.
    Al-Emrani, M.
    Robustness of the HFMI techniques and the effect of weld quality on the fatigue life improvement of welded joints2020In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 64, no 11, p. 1947-1956Article in journal (Refereed)
    Abstract [en]

    Robustness of HFMI treatment in different weld qualities according to ISO 5817 was studied, and fatigue testing of the treated samples was carried out in order to investigate the effect of the weld quality prior treatment. The results show that HFMI-treated welds with weld quality level D shows fatigue life improvements that fall within the IIW recommendations for HFMI. No significant influence from the HFMI operator or HFMI equipment on the fatigue life was found. However, the scatter in fatigue testing results varied with HFMI operator and indicated that different HFMI operators could produce consistent treatment results. A considerable effect on fatigue life from HFMI tool radius was found, where the 2-mm tool radius showed considerably greater fatigue life compared with the 1.5-mm tool radius. According to IIW (Marquis and Barsoum 2016), for steel grade SY = 700 MPa, the fatigue strength recommendation is FAT 160 (m = 5) for transverse stiffener–welded joints with as-welded quality B according to ISO 5817 (ISO/TC 44/SC 10 2011), prior to treatment. It can be observed in the current study that fatigue-tested HFMI-treated welded joints, welded with weld quality D, are in good agreement with the IIW recommendations.

  • 6.
    Aldén, Rickard
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Metallurgical investigation in weldability of Aluminium Silicon coated boron steel with different coating thickness.2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Hot-pressed aluminium and silicon coated boron steel is used in the car industry where high tensile strength is of great importance, such as in the safety cage of a car where deformation has to be kept to a minimum in case of a collision. After hot-pressing the AlSi-boron steel shows excellent properties with high tensile strength, minimal spring back and also shows good protection against corrosion. A thickness of the AlSi coating of 150 [g/m2] for AlSi coated boron steel is typically used by the car industry today. However the coating thickness would be desirable to be minimized to 80 [g/m2]. Welding of this boron steel with 80 [g/m2]have shown difficulties; and it’s not clear why this occurs.

    In this report the metallurgical properties of the different coating layers will be investigated, simulations with Thermocalc module Dictra will be used, SEM/EDS will be used to characterize phases in coating layers and correlate to weldability. Resistance spot welding tests will also be performed where the welding parameters of pre-pulse, pulse time, time in between pulses and current will be varied to achieve desirable weld plug diameter without expulsion. Hardness testing in form of micro Vickers will executed. The Materials used will be USIBOR® 1500, AS80 with four different annealing times and one sample of AS150.

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    fulltext
  • 7.
    Al-Emrani, M.
    et al.
    Chalmers Univ Technol, Gothenburg, Sweden..
    Shams-Hakimi, P.
    Chalmers Univ Technol, Gothenburg, Sweden..
    Schneider, C.
    Swerea Kimab, Stockholm, Sweden..
    Barsoum, Zuheir
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Groth, H.
    Outokumpu, Degerfors, Sweden..
    Fatigue improvement of welded bridge details In stainless steel using High-Frequency Mechanical Impact treatment2018In: Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges: Proceedings of the Ninth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2018) / [ed] Powers, N Frangopol, DM AlMahaidi, R Caprani, C, CRC PRESS-TAYLOR & FRANCIS GROUP , 2018, p. 446-451Conference paper (Refereed)
    Abstract [en]

    This paper reports the results from fatigue testing on welded non-load-carrying transverse attachments made of C-Mn (S460) and stainless (LDX2101) steels. The tests are done on 40 mm thick specimens in as-welded and HFMI-treated specimens. Measurements on weld toe radius and weld residual stresses are also reported. The results show that the improvement of fatigue strength that can be achieved by HFMI-treatment on welded LDX2101 steel is similar to what is obtained for equivalent C-Mn steels. Also in the as-welded condition do these two types of steel show similar fatigue strength. HFMI-treatment gives more than 5 steps increase in fatigue strength for both steels, which is higher than what specified, for example by the recommendations of the International Institute of Welding.

  • 8.
    Alinejadian, Navid
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Tallinn Univ Technol TalTech, Dept Mech & Ind Engn, Ehitajate Tee 5, EE-19086 Tallinn, Estonia..
    Kollo, Lauri
    Tallinn Univ Technol TalTech, Dept Mech & Ind Engn, Ehitajate Tee 5, EE-19086 Tallinn, Estonia..
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Karolinska Inst, AIMES Ctr Adv Integrated Med & Engn Sci, Stockholm, Sweden.;KTH Royal Inst Technol, Stockholm, Sweden.;Karolinska Inst, Dept Neurosci, SE-17177 Stockholm, Sweden..
    Progress in additive manufacturing of MoS2-based structures for energy storage applications - A review2022In: Materials Science in Semiconductor Processing, ISSN 1369-8001, E-ISSN 1873-4081, Vol. 139, article id 106331Article, review/survey (Refereed)
    Abstract [en]

    Investigation of next-generation manufacturing methods for the processing of functional materials and offering products with improved performance/functionalities has always been a challenge in terms of energy efficiency, cost-effectiveness, and eco-friendliness. Additive manufacturing (AM) attributes to rapid prototyping techniques that provide new opportunities to test new concepts and design complex 3D structures from metals, ceramics, and composites. Moreover, as a well-known transition metal dichalcogenide, Molybdenum disulfide (MoS2) is a two-dimensional (2D) material with outstanding electrochemical, physical, and mechanical properties that make it a potential candidate for energy storage electrodes via intercalation of different H+, Li+, Na+, and K+ cations. In this review, we discuss the existing conventional MoS2-processing methodologies and compare them with the novel additive manufacturing processes (especially laser-based powder bed fusion). The authors are convinced that the processing of prominent MoS2-based functional structures by the novel additive manufacturing processes can provide complex structures for different electrochemical applications, particularly for energy conversion/ storage systems.

  • 9.
    Alipour, Yousef
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Machining of CoCr28Mo62011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The machining process of Cobait-Chromium medical ailoys become a veryessential topic for research due to widening range of application. They aregeneraily used because of their high wear resistance, low corrosioncharacteristics and high fatigue strength. This project describes an investigationof chip formation during the machining of Cobalt-Chromium-Molybdenum highcarbon alloy. A quick stop device has been employed to investigate mechanismof chip formation through analyzing of shear zone and shear plane. Thicknessmeasurement of segments, surface conditions after finishing, lowest valley andhighest peak with three different cutting tool inserts were studied as weil.Moreover cutting force measurement at different cutting speeds, feeds and radialnoses were performed. Microstructure and hardness of work material before andafter machining has been studied. Tool life of inserts was evaluated bymeasuring flank wear.

    The consequences obtained from the study illuminated:

    1. For the constant cutting speed and nose radius flank wear increased whenthe feed increased.
    2. For the constant feed and nose radius, increase in the cutting speedlowered flank and crater wear.
    3. Cutting force increased with the increase in feed.
    4. Increase in cutting speed to 40 m/min raised cutting force. However afterthat cutting force decreased.
    5. Insert CNMG 120408-MF1 TS2000 with cutting data v~=70 m/min, ap= 3mm and f=0.1 mm seemed fit the best in base of lower flank and craterwear, almost lower cutting force and smoother finish roughness.
  • 10.
    Al-Saadi, Munir
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Microstructures and mechanical properties: Forged vs rolled bar in Sanmac 22052016In: Stainless Steel World, ISSN 1383-7184, Vol. 28, no July/August, p. 45-48Article in journal (Refereed)
  • 11.
    Al-Saadi, Munir
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Sandberg, Fredrik
    Karasev, Andrey
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Jonsson, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Microstructure characterisation in alloy 8252018Conference paper (Refereed)
  • 12.
    Al-Saadi, Munir
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Karasev, Andrey
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Sandberg, Fredrik
    Comparative Study of Microstructures Evolution of Columnar and Equiaxed Grain Structurs in Alloy 825 after Hot Compression2018In: 3rd InternationalConference on Ingot Casting, Rolling and Forging, ICRF2018, in Stockholm, 16-19October, 2018, article id 114Conference paper (Refereed)
  • 13.
    Araya, Juan Manuel
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Economics and Management (Div.).
    Value Stream Mapping Adapted to High-Mix, Low-Volume Manufacturing Environments2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This research work proposes a new methodology for implementing Value Stream Mapping, in processes that feature a High-Mix, Low-Volume product base.   The opportunity for adapting the methodology singularly for these types of environments was identified because implementing Value Stream Mapping as proposed in Learning to See features several drawbacks when implemented in High-Mix, Low-Volume.  Although Value Stream Mapping has been proven to enhance many types of processes, its advantages are shrunk if they are implemented in High-Mix, Low-Volume processes.  

    High-Mix, Low-Volume processes are types of processes in which a high variety of finished goods are produced in relatively low amounts.  The high variety of finished goods causes several complications for the implementation of flow.  The difficulties that prevent the flow are the following:

    • The variance in the products: With hundreds, or sometimes thousands of possible finished goods, the number of products causes a non-repetitive process.
    • The variance in the routings:  All of the products that are produced can have completely different process routings, or order of stations it has to visit.  This makes the application of production lines quite difficult.
    • The variance in the cycle times for each process.  Each of the different products can have completely different capacity requirements at a specific machine, which limits the predictability of the process.

     

    This purpose of the thesis is to gather the best practices for controlling and improving High-Mix, Low-Volume processes and merge them with some innovative ideas to create an inclusive Value Stream Mapping methodology which is better fitted with the types of complications in High-Mix, Low-Volume environments.  In parallel, the methodology is tested with the company: Boston Scientific, in their Ureteral Stents manufacturing process.   The real-life experimentation will allow for the fine-tuning of the methodology, in order to truly create impact in the process.

     

     

     

     

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    2012:120
  • 14. Arvidsson, M.
    et al.
    Ringstad, L.
    Skedung, L.
    Duvefelt, Kenneth
    KTH, School of Industrial Engineering and Management (ITM).
    Rutland, Mark W.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Feeling fine - the effect of topography and friction on perceived roughness and slipperiness2017In: Biotribology, ISSN 2352-5738, Vol. 11, p. 92-101Article in journal (Refereed)
    Abstract [en]

    (1) Background. To design materials with specific haptic qualities, it is important to understand both the contribution of physical attributes from the surfaces of the materials and the perceptions that are involved in the haptic interaction. (2) Methods. A series of 16 wrinkled surfaces consisting of two similar materials of different elastic modulus and 8 different wrinkle wavelengths were characterized in terms of surface roughness and tactile friction coefficient. Sixteen participants scaled the perceived Roughness and Slipperiness of the surfaces using free magnitude estimation. Friction experiments were performed both by participants and by a trained experimenter with higher control. (3) Results and discussion. The trends in friction properties were similar for the group of participants performing the friction measurements in an uncontrolled way and the experiments performed under well-defined conditions, showing that the latter type of measurements represent the general friction properties well. The results point to slipperiness as the key perception dimension for textures below 100 μm and roughness above 100 μm. Furthermore, it is apparent that roughness and slipperiness perception of these types of structures are not independent. The friction is related to contact area between finger and material. Somewhat surprising was that the material with the higher elastic modulus was perceived as more slippery. A concluding finding was that the flat (high friction) reference surfaces were scaled as rough, supporting the theory that perceived roughness itself is a multidimensional construct with both surface roughness and friction components.

  • 15.
    Badal Tejedor, Maria
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Stockholm, Sweden..
    Nordgren, Niklas
    RISE Res Inst Sweden, Stockholm, Sweden..
    Schuleit, Michael
    Novartis Pharma AG, Basel, Switzerland..
    Millqvist-Fureby, Anna
    RISE Res Inst Sweden, Stockholm, Sweden..
    Rutland, Mark W.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Stockholm, Sweden..
    AFM colloidal probe measurements implicate capillary condensation in punch-particle surface interactions during tableting2019In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 257Article in journal (Other academic)
  • 16.
    Banno, Yuki
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. Gifu University, Gifu, Japan.
    Kinoshita, K.
    Barsoum, Zuheir
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Numerical investigation of crack opening-closing behavior on pre-fatigued welded joints repaired by HFMI2022In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 66, no 4, p. 767-781Article in journal (Refereed)
    Abstract [en]

    This study aims to understand crack opening-closing behavior on pre-fatigued welded joints repaired by High Frequency Mechanical Impact (HFMI). Detailed rat-hole specimen models inserting different depths of rectangle slit in the weld toes to simulate initial cracks were used in the HFMI treatment simulation. Induced compressive residual stress, change of slit geometry, and opening-closing behavior of the slit after HFMI treatment simulation were investigated numerically. The amount of induced compressive residual stress around the slit tip is reduced when slit depth becomes larger, and slit size of about 0.4 mm remains when the slit depth is 2.0 mm. The opening-closing behavior of HFMI treated slit was examined based on change of strains along the slit face. The slit is opened from the bottom side prior to its treated surface. Additionally, the crack opening-closing behavior was investigated experimentally using pre-fatigued out-of-plane gusset welded joints repaired by impact crack closure retrofit treatment. Phased array ultrasonic testing system was used to examine the change of echo height from cracks. It could be concluded that similar behavior as the numerical investigation is observed. From both investigations, experimentally and numerically, the behavior on pre-fatigue welded joints repaired by HFMI could be studied successfully. 

  • 17.
    Banno, Yuki
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. Department of Civil Engineering, Gifu University, Gifu, Japan.
    Kinoshita, K.
    Barsoum, Zuheir
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Numerical investigation of influence of under- and over- treatment on residual stress state induced by HFMI2021In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 65, no 11, p. 2135-2146Article in journal (Refereed)
    Abstract [en]

    This study aims to investigate influence of under- and over-treatment on residual stress state induced by HFMI numerically. Finite element simulations were performed using a flat plate model considering S355 where feed rate and the number of hits were varied. To reduce computational time, the mass scaling method was adopted to the simulations. In addition, in order to survey influence of surface removal on residual stress state, electropolishing was conducted after the HFMI simulation. Additional simulations were performed on bead on plate model considering JIS-SM400 in order to investigate applicability of isotropic hardening model for residual stress estimation. From the results, the mass scaling method can result in reducing computational time more than 90% with reasonable good estimation of the residual stresses.The investigations regarding under- and over-treatment reveal that high feed rate mainly influences residual stress state on the treated surface and the number of hits is independent of amount of induced residual stress. Surface removal after the simulation can result in slightly improving the accuracy of the estimated residual stresses. The simulations to bead on plate model give reasonable results in a depth of around 0.2 mm even when the residual stresses due to welding is disregarded. 

  • 18.
    Banno, Yuki
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Kinoshita, K.
    Ishikawa, T.
    Anami, K.
    Influence of grid blast on the fatigue strength improvement by peening2021In: Bridge Maintenance, Safety, Management, Life-Cycle Sustainability and Innovations - Proceedings of the 10th International Conference on Bridge Maintenance, Safety and Management, IABMAS 2020, CRC Press/Balkema , 2021, p. 3165-3173Conference paper (Refereed)
    Abstract [en]

    In this study, to evaluate the influence of grid blast following to the peening process on the fatigue strength improvement, residual stress measurement and fatigue tests have been conducted. Examined peening processes were UIT, PPP and HP with ICR apparatus. For the residual stress measurement, plate and on-bead specimens made of JIS-SM400, SBHS400, SBHS500 and SBHS700 were used, and X-ray diffraction method was applied to the measurement. The results concluded that the differences in the compressive residual stress distribution in the vicinity of peened area with and without blast are not so significant. For the fatigue tests, out-of-plane gusset welded joint specimens made of JIS-SM490 and SBHS500 were used. Fatigue tests were conducted under stress ratio R=0.0 and 0.5. Fatigue tests showed that fatigue strength of peened specimens with blast are almost the same as that of peened specimens without blast, and those results were observed independently of steel grade and of peening methods.

  • 19.
    Barsoum, Zuheir
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Khurshid, Mansoor
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. Cargotec Sweden AB.
    Ultimate Strength Capacity of Welded Joints in High Strength Steels2017In: 2nd International Conference on Structural Integrity, ICSI 2017 / [ed] Iacoviello, F Moreira, PMGP Tavares, PJS, Elsevier, 2017, Vol. 5, p. 1401-1408Conference paper (Refereed)
    Abstract [en]

    High strength steels are nowadays used in a wide range of weight lifting applications, e.g. spreaders and cranes, where there is a demand on lightweight design of these structures with increased structural performance where the welds become more sensitive to failure. This study focuses on investigating the influence of the mismatch in the yield strength of the weld filler material and the welds penetration depth on the ultimate strength capacity and failure modes of butt and fillet welded high strength steels of yield strength in the range of 350 960 MPa. The load carrying capacities of these mentioned joints are evaluated with experiments and compared with the estimations by finite element analysis (FEA), and design rules in Eurocode 3 and American Welding Society Code AWS D1.1. Fully penetrated joint with under-matched filler material is more ductile and the ultimate strength capacity of base plate can be achieved. It is observed that joints with under-matched filler material are more sensitive to penetration ratio. This influence is more pronounced in joints in S960 steel welded with under-matched filler material. It is also found that the design rules in Eurocode3 (valid for design of welded joints in steels of grade up to S700) can be extended to designing of welds in S960 steels using correlation factor of one.

  • 20.
    Bautin, V. A.
    et al.
    National University of Science and Technology MISIS, 119049, Moscow, Russian Federation.
    Zadorozhnyy, V. Yu
    National University of Science and Technology MISIS, 119049, Moscow, Russian Federation.
    Korol, A. A.
    National University of Science and Technology MISIS, 119049, Moscow, Russian Federation.
    Bazhenov, V. E.
    National University of Science and Technology MISIS, 119049, Moscow, Russian Federation.
    Shinkarev, A. S.
    National University of Science and Technology MISIS, 119049, Moscow, Russian Federation.
    Chernyshikhin, S. V.
    National University of Science and Technology MISIS, 119049, Moscow, Russian Federation.
    Moskovskikh, D. O.
    National University of Science and Technology MISIS, 119049, Moscow, Russian Federation.
    Samoshina, M. E.
    National University of Science and Technology MISIS, 119049, Moscow, Russian Federation.
    Khort, Aliaksandr
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Selective laser melting of low-alloyed titanium based alloy with a large solidification range2024In: Heliyon, E-ISSN 2405-8440, Vol. 10, no 3, article id e25513Article in journal (Refereed)
    Abstract [en]

    In this work, thermodynamic calculations for α + β Type Ti–Fe–Cu–Sn alloy were carried out by the Thermo-Calc software. Powders from this alloy were obtained by plasma sputtering and used for subsequent 3D printing of experimental samples. The effect of various selective laser melting (SLM) parameters on porosity and hot cracking susceptibility as well as the electrochemical characteristics of the alloy have been studied. The optimal technological regime for the manufacture of samples by the SLM method was determined. It has been established that to obtain relatively dense samples without cracks, regimes with volumetric energy density Ev = 250–300 J/mm3 are required. It has been established that a change in the electrochemical behavior of the Ti94Fe1Cu1Sn4 alloy is related to the formation of a nonequilibrium Ti2Cu phase. Based on the findings we recomended directions for further research.

  • 21.
    Bergstedt, Edwin
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    A Study in How Welding Parameters Affect the Porosity in Laser Welded High Pressure Die Cast AM50 Magnesium Alloy2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There are a need for reducing the weight of vehicles, one solution is to implement cast lightweight materials such as the high pressure die cast AM50 magnesium alloy. The weldability of this cast alloy is poor and to implement the use of the alloy commercially a welding process is needed that limits the porosity of the weld. The aim of this thesis is to study the effect of the welding parameters on the porosity in the weld, for three laser welding methods. The welding methods examined are single spot and twin spot laser using either a beam splitter or separate optics. The microstructure of the base material are also examined in order to evaluate relations between the components of the microstructure and the porosity in the weld. It was concluded that the hydrogen in the base material was the main reason for the observed porosity in the weld and that the material contains high pressure gas. The welding parameters did not influence the porosity for the single beam laser process, however, for the dual beam processes the welding parameters could affect the amount of pores. It was found that a double weld reduced the amount of pores and that the size and distribution of the secondary phase particles would benefit from the treatment. The cleaning of the samples prior to welding increased the porosity, however, non-cleaned samples contained more oxide inclusions. The results indicate that a twin beam process could reduce the porosity in the weld of the AM50 alloy.

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  • 22.
    Bergsåker, B. Henric M.
    et al.
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics. EUROfusion Consortium, Culham Science Centre, JET, Abingdon, United Kingdom.
    Bykov, Igor
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics. EUROfusion Consortium, Culham Science Centre, JET, Abingdon, United Kingdom.
    Zhou, Yushan
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics. EUROfusion Consortium, Culham Science Centre, JET, Abingdon, United Kingdom.
    Petersson, Per
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics. EUROfusion Consortium, Culham Science Centre, JET, Abingdon, United Kingdom.
    Possnert, G.
    Likonen, J.
    Pettersson, J.
    Koivuranta, S.
    Widdowson, A. M.
    Deep deuterium retention and Be/W mixing at tungsten coated surfaces in the JET divertor2016In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T167, article id 014061Article in journal (Refereed)
    Abstract [en]

    Surface samples from a full poloidal set of divertor tiles exposed in JET through operations 2010-2012 with ITER-like wall have been investigated using SEM, SIMS, ICP-AES analysis and micro beam nuclear reaction analysis (μ-NRA). Deposition of Be and retention of D is microscopically inhomogeneous. With careful overlaying of μ-NRA elemental maps with SEM images, it is possible to separate surface roughness effects from depth profiles at microscopically flat surface regions, without pits. With (3He, p) μ-NRA at 3-5 MeV beam energy the accessible depth for D analysis in W is about 9 μm, sufficient to access the W/Mo and Mo/W interfaces in the coatings and beyond, while for Be in W it is about 6 μm. In these conditions, at all plasma wetted surfaces, D was found throughout the whole accessible depth at concentrations in the range 0.2-0.7 at% in W. Deuterium was found to be preferentially trapped at the W/Mo and Mo/W interfaces. Comparison is made with SIMS profiling, which also shows significant D trapping at the W/Mo interface. Mixing of Be and W occurs mainly in deposited layers.

  • 23.
    Beza, Abebe Dress
    et al.
    Bahir Dar Univ, Fac Civil & Water Resources Engn, Bahir Dar Inst Technol, POB 26, Bahir Dar, Ethiopia.;Univ Mons, Fac Engn, B-7000 Mons, Belgium..
    Zefreh, Mohammad Maghrour
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Torok, Adam
    Budapest Univ Technol & Econ, Dept Transport Technol & Econ, H-1111 Budapest, Hungary.;KTI Inst Transport Sci, Dept Transport Policy & Econ, H-1111 Budapest, Hungary..
    Impacts of Different Types of Automated Vehicles on Traffic Flow Characteristics and Emissions: A Microscopic Traffic Simulation of Different Freeway Segments2022In: Energies, E-ISSN 1996-1073, Vol. 15, no 18, article id 6669Article in journal (Refereed)
    Abstract [en]

    Different types of automated vehicles (AVs) have emerged promptly in recent years, each of which might have different potential impacts on traffic flow and emissions. In this paper, the impacts of autonomous automated vehicles (AAVs) and cooperative automated vehicles (CAVs) on capacity, average traffic speed, average travel time per vehicle, and average delay per vehicle, as well as traffic emissions such as carbon dioxide (CO2), nitrogen oxides (NOx), and particulate matter (PM10) have been investigated through a microsimulation study in VISSIM. Moreover, the moderating effects of different AV market penetration, and different freeway segments on AV's impacts have been studied. The simulation results show that CAVs have a higher impact on capacity improvement regardless of the type of freeway segment. Compared to other scenarios, CAVs at 100% market penetration in basic freeway segments have a greater capacity improvement than AAVs. Furthermore, merging, diverging, and weaving segments showed a moderating effect on capacity improvements, particularly on CAVs' impact, with merging and weaving having the highest moderating effect on CAVs' capacity improvement potential. Taking average delay per vehicle, average traffic speed, and average travel time per vehicle into account, simulation results were diverse across the investigated scenarios. The emission estimation results show that 100% AAV scenarios had the best performance in emission reductions in basic freeway and merging sections, while other scenarios increased emissions in diverging and weaving sections.

  • 24.
    Bhatti, Ayjwat Awais
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Computational weld mechanics: Towards simplified and cost effective FE simulations2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    It is the demand of the world’s ever increasing energy crisis to reduce fuel consumption wherever possible. One way of meeting this demand is by reducing the weight of a structure by replacing thick plates of low strength steel with thin plates of high strength steel in the structure. Fusion welding process is extensively used in the manufacturing industry, however, despite many advantages different problems such as weld defects, residual stresses and permanent distortions are associated with this process.

    Finite element (FE) method has proved itself as an alternative and acceptable tool for prediction of welding residual stresses and distortions. However, the highly nonlinear and transient nature of the welding process makes the FE simulation computationally intensive and complex. Thus, simplified and efficient welding simulations are required so that they can be applied to industrial scale problems.

    In this research work an alternative FE simulation approach for the assessment of welding residual stresses, called rapid dumping is developed. This approach proved to be efficient and predicted the residual stress with acceptable accuracy for different small scale welded joints. This approach was further implemented on a large scale welded structures along with other available approaches. It was found that the computational time involved in the welding simulations for large structures using rapid dumping approach can be reduced but at the cost of accuracy of the results.

    Furthermore, influence of thermo-mechanical material properties of different steel grades (S355-S960) on welding residual stresses and angular distortion in T-fillet joints is investigated. It is observed that for assessment of residual stresses, except yield stress, all of the thermo-mechanical properties can be considered as constant. For the prediction of angular distortions with acceptable accuracy, heat capacity, yield stress and thermal expansion should be employed as temperature dependent in the welding simulations.

    Finally, the influence of two different LTT (Low Transformation Temperature) weld filler material on residual stress state and fatigue strength was investigated. It was observed that a reduction in tensile residual stresses at the weld toe of the joint was observed. Furthermore, at higher R-ratio no significant increase in the fatigue strength was observed . However, at low R-ratio significant  increase in fatigue strength was observed.

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    Thesis
  • 25.
    Bjerke, Axel
    et al.
    Lund Univ, Div Prod & Mat Engn, Ole Romers Vag 1, Lund, Sweden..
    Hrechuk, Andrii
    Lund Univ, Div Prod & Mat Engn, Ole Romers Vag 1, Lund, Sweden..
    Lenrick, Filip
    Lund Univ, Div Prod & Mat Engn, Ole Romers Vag 1, Lund, Sweden..
    Markstrom, Andreas
    Thermocalc Software AB, Rasundavagen 18, SE-16967 Solna, Sweden..
    Larsson, Henrik
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Norgren, Susanne
    Sandvik R&D, Lerkrogsv 13, S-12680 Stockholm, Sweden..
    M'Saoubi, Rachid
    Seco Tools AB, R&D Mat & Technol Dev, S-73782 Fagersta, Sweden..
    Bjork, Thomas
    Ovako Grp, Olof Hjorts Vag 2, S-81335 Hofors, Sweden..
    Bushlya, Volodymyr
    Lund Univ, Div Prod & Mat Engn, Ole Romers Vag 1, Lund, Sweden..
    Thermodynamic modeling framework for prediction of tool wear and tool protection phenomena in machining2021In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 484-485, article id 203991Article in journal (Refereed)
    Abstract [en]

    Chemical, oxidational and diffusional interactions between the tool, chip and cutting environment are known tool wear mechanisms in machining. However, the interaction between tool, coating, workpiece, coolant and atmospheric oxygen can, under favorable conditions, lead to formation of reaction products that retard tool wear. A method with the ability to predict theses interactions, would therefore enable a better control over tool life in machining. An attempt to create such a modelling framework is developed in this study. This method can predict the phase composition and the driving force for degradation and the formation of protective interaction products in the cutting zone. This modeling approach is applicable across cutting processes in which chemical, diffusional and oxidational wear are dominant or present. This framework has been applied to investigate the interactions occurring in the cutting zone during turning of a medium alloyed low-carbon steel (Hybrid Steel (R) 55). A range of degradation events are predicted, as well as the formation of a protective corundum (Al,Fe,Cr)(2)O-3 or spinel (Al, Fe,Cr)(3)O-4 film due to an interaction between the Al-alloyed steel and the environment. Validation of the modeling was performed by studying tool wear and reaction products formed when machining with ceramics, PcBN and coated carbide tooling. Inserts are studied by the use of scanning and transmission electron microscopy, after cutting tests were performed. Additional tests were performed in different environments (dry, argon and coolant). The results confirmed the model predictions of oxidation and diffusion wear as well as the formation of an (Al,Fe,Cr)(3)O-4 tool protection layer. Thus, the proposed thermodynamic framework seem promising to serve as a predictive instrument for the correct pairing of existing tool and workpiece combinations and cutting parameters, or for tailoring respective material compositions for intentional formation of a tool protection layer. As well as guidance on how to apply present and future kinetic models when concurrent interaction mechanisms are present. Which lead to a reduction and minimization of costly experimental machining tests.

  • 26.
    Bjerke, Axel
    et al.
    Lund Univ, Div Prod & Mat Engn, Ole Romers Vag 1, Lund, Sweden..
    Hrechuk, Andrii
    Lund Univ, Div Prod & Mat Engn, Ole Romers Vag 1, Lund, Sweden..
    Lenrick, Filip
    Lund Univ, Div Prod & Mat Engn, Ole Romers Vag 1, Lund, Sweden..
    M'Saoubi, Rachid
    Seco Tools AB, R&D Mat & Technol Dev, S-73782 Fagersta, Sweden..
    Larsson, Henrik
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures.
    Markström, Andreas
    Thermo Calc Software AB, Rasundavagen 18, SE-16967 Solna, Sweden..
    Björk, Thomas
    Ovako Grp, Olof Hjorts Vag 2, S-81335 Hofors, Sweden..
    Norgren, Susanne
    Sandvik Coromant R&D, Lerkrogsv 13, S-12680 Stockholm, Sweden..
    Ståhl, Jan-Eric
    Lund Univ, Div Prod & Mat Engn, Ole Romers Vag 1, Lund, Sweden..
    Bushlya, Volodymyr
    Lund Univ, Div Prod & Mat Engn, Ole Romers Vag 1, Lund, Sweden..
    Onset of the degradation of CVD alpha-Al2O3 coating during turning of Ca-treated steels2021In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 477, article id 203785Article in journal (Refereed)
    Abstract [en]

    The ability to control the shape, distribution and composition of non-metallic inclusions has had an important impact on many aspects of steel making. One such impact is on the machinability. Ca-treatments have shown to be able to reduce the abrasiveness of oxide inclusions, improve chip-breaking and lead to formation of deposits that reduce tool wear. However, machining Ca-treated steels with Al2O3 coated cemented carbide tools has not been as advantageous as expected. This study investigates the mechanisms behind the anomalous wear of Al2O3 coatings when turning soft Ca-treated steels. Longitudinal turning tests at a range of speeds (vc = 100-600 m/min) show rapid localized degradation of the Al2O3 coating limited to the sliding zone. Detailed analysis of the degradation mechanisms was performed using scanning and transmission electron microscopy. The results demonstrate a presence of chemical interactions between the alumina coating and non-metallic inclusions. The interaction resulted in the formation of mainly calcium aluminates and partly alumina-magnesia spinel. In-operando infrared thermography measurements indicate cutting temperatures of 850-1000 degrees C. Thermodynamic calculations give that CaO and MgO readily reacts with Al2O3, while the reaction with CaS requires presence of additional oxygen at these cutting conditions. Additional turning experiments investigate the influence of oxygen by controlling the cutting environment by adding oxygen (compressed air) or removing oxygen (supply argon). These additional tests show that the presence of additional oxygen has a limited impact on the possible Ca-Al2O3 interaction. This demonstrat a potential for further machinability improvements by controlling the chemical interaction between Ca and Mg based non-metallic inclusions and alumina coatings.

  • 27.
    Bjurman, Martin
    et al.
    KTH. Studsvik Nuclear AB, Nyköping, Sweden.
    Lindgren, K.
    Chalmers University of Technology, Gothenburg, Sweden.
    Thuvander, M.
    Chalmers University of Technology, Gothenburg, Sweden.
    Ekström, P.
    Swedish Radiation Safety Authority, Solna, Sweden.
    Efsing, Pål
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.). Ringhals AB, Väröbacka, Sweden.
    Microstructural evolution of welded stainless steels on integrated effect of thermal aging and low flux irradiation2019In: Proceedings of the 18th International Conference on Environmental Degradation of Materials in Nuclear Power Systems – Water Reactors: Microstructural Evolution of Welded Stainless Steels on Integrated Effect of Thermal Aging and Low Flux Irradiation, Springer International Publishing , 2019, p. 1919-1926Conference paper (Refereed)
    Abstract [en]

    The combined effect of thermal aging and irradiation on cast and welded stainless steel solidification structures is not sufficiently investigated. From theory and consecutive aging and irradiation experiments, the effect of simultaneous low rate irradiation and thermal aging is expected to accelerate and modify the aging processes of the ferrite phase. Here, a detailed analysis of long-term aged material at very low fast neutron flux at LWR operating temperatures using Atom Probe Tomography is presented. Samples of weld material from various positions in the core barrel of the Zorita PWR are examined. The welds have been exposed to 280–285 °C for 38 years at three different neutron fluxes between 1 × 10 −5 and 7 × 10 −7 dpa/h to a total dose of 0.15–2 dpa. The aging of the ferrite phase occurs by spinodal decomposition, clustering and precipitation of e.g. G-phase. These phenomena are characterized and quantitatively analyzed in order to understand the effect of flux in combination with thermal aging.

  • 28.
    Bleiker, Simon J.
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Dubois, Valentin J.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Schröder, Stephan
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Ottonello Briano, Floria
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Gylfason, Kristinn B.
    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.
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Adhesive Wafer Bonding for Heterogeneous System Integration2018In: ECS Meeting Abstracts / [ed] The Electrochemical Society, 2018Conference paper (Refereed)
  • 29.
    Bobyr, Serhii
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures. Iron and Steel Institute of Z. I. Nekrasov, National Academy of Sciences of Ukraine, 49107 Dnipro, Ukraine.
    Krot, Pavlo
    Faculty of Geoengineering, Mining and Geology, Wroclaw University of Science and Technology, Wrocław, 50-370, Poland.
    Parusov, Eduard
    Iron and Steel Institute of Z. I. Nekrasov, National Academy of Sciences of Ukraine, 49107 Dnipro, Ukraine;.
    Golubenko, Tetiana
    Iron and Steel Institute of Z. I. Nekrasov, National Academy of Sciences of Ukraine, 49107 Dnipro, Ukraine;.
    Baranovs’ka, Olena
    Iron and Steel Institute of Z. I. Nekrasov, National Academy of Sciences of Ukraine, 49107 Dnipro, Ukraine;.
    Increasing the Wear Resistance of Structural Alloy Steel 38CrNi3MoV Subjected to Isothermal Hardening and Deep Cryogenic Treatment2023In: Applied Sciences, E-ISSN 2076-3417, Vol. 13, no 16, article id 9143Article in journal (Refereed)
    Abstract [en]

    In the production of critical parts for various machines and mechanisms, expensive structural steels are used alloyed with chromium, nickel, molybdenum, and vanadium. In practice, the wear resistance of parts, especially under severe operating conditions, may be insufficient due to uneven microstructure and the content of retained austenite. Therefore, increasing the operational stability of various products made of alloy steels is an important task. The purpose of this work is to investigate the effect of isothermal hardening from the intermediate (γ+α)-area and the duration of deep cryogenic treatment on the structure formation and frictional wear resistance of 38CrNi3MoV steel. The isothermal hardening promotes the formation of the required multiphase microstructure of 38CrNi3MoV steel. The influence of the duration of deep cryogenic treatment on the microhardness, amount of retained austenite, fine structure parameters, and friction wear of 38CrNi3MoV steel are established. Complex heat treatment of 38CrNi3MoV steel, according to the proposed mode, makes it possible to achieve a significant decomposition of retained austenite to martensite, which leads to an increase in frictional wear resistance of ~58%.

  • 30.
    Bogdan, Felix
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Evaluation of different block-copolymer coatings of iron oxide nanoparticles by flash nanoprecipitation2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nanoparticles (NPs) offer unique possibilities for medical applications, including the controlled release of cancer drugs, the use as imaging contrast during imaging procedures or the hyperthermic treatment of cancer cells. Flash nanoprecipitation (FNP) produces NPs to combine these applications in a fast, cheap, and scalable coating process. The use of FNP with a Multi-Inlet Vortex Mixer (MIVM) is a promising method to easily coat hydrophobic oleic acid iron oxide NPs (IONPs) with various biocompatible block-copolymers. Amphiphilic block-copolymers based on hydrophilic polyethylene glycol (PEG) and hydrophobic poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA) or poly(caprolactone) (PCL) were successfully synthesized. The organic catalyst 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was used to increase biocompatibility of the resulting polymers PEG-PLA, PEG-PL7.5KG2.5KA and PEG2K-PCL2K. The synthesis of hydroxyl terminated poly(acrylic acid) (PAA-OH) followed by the polymerization with PLGA was attempted. The amphiphilic block-copolymers were used in combination with the stabilizer polysorbate 80 (Tween80®) in FNP to form bare polymeric NPs using a MIVM as the reactor. DLS and STEM confirmed particle sizes between 50 - 100 nm. The addition of 13 ± 2 nm hydrophobic oleic acid IONPs yielded an increase in particle size as well as increase in particle stability over time. STEM images showed attachment of single IONPs to the outside of the polymeric NPs. Hydrophobic interactions between the polymer and oleic acid IONPs are possible. To achieve encapsulation of the oleic acid IONPs, adjustments to the process parameters of FNP should be considered in future research. Additional experiments are required to explore possible drug addition, release mechanisms and hyperthermia behavior of the polymer coated IONPs particles.

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  • 31.
    Boor, Katalin
    et al.
    Uppsala Univ, Dept Chem, SE-5120 Uppsala, Sweden..
    Qiu, Ren
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Forslund, Axel
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Backe, Olof
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Larsson, Henrik
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Physical Metallurgy.
    Lindahl, Erik
    AB Sandvik Coromant, SE-12679 Hagersten, Sweden..
    Halvarsson, Mats
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Boman, Mats
    Uppsala Univ, Dept Chem, SE-5120 Uppsala, Sweden..
    von Fieandt, Linus
    AB Sandvik Coromant, SE-12679 Hagersten, Sweden..
    Chemical vapor deposition of TiN on a CoCrFeNi multi-principal element alloy substrate2020In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 393, article id 125778Article in journal (Refereed)
    Abstract [en]

    The reactivity of a quaternary multi-principal element alloy (MPEA), CoCrFeNi, as a substrate in thermal halide chemical vapor deposition (CVD) processes for titanium nitride (TiN) coatings was studied. The coatings were deposited at 850 degrees C-950 degrees C using TiCl4, H-2 and N-2 precursors. The coating microstructures were characterized using X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM/TEM) with energy dispersive X-ray spectroscopy (EDS). Thermodynamic calculations of substrate and coating stability for a gas phase environment of N-2 and H-2 within a temperature range relevant for the experiments showed that Cr is expected to form hexagonal Cr2N and cubic (Ti1-epsilon 1 Cr epsilon 1)N or (Cr1-epsilon 2 Ti epsilon 2)N phases. These phases could however not be discerned in the samples by XRD after the depositions. Cr was detected at the grain boundaries and the top surface by EDS for a sample synthesized at 950 degrees C. Grain boundary and surface diffusion, respectively, were the suggested mechanisms for Cr transport into the coating and onto the top surface. Although thermodynamic calculations indicated that Cr is the most easily etched component of the CoCrFeNi alloy to form gaseous chlorides in similar concentrations to that of the residual Ti-chlorides, no sign of etching were found according to the imaging of the sample cross-sections using SEM and TEM. Cross-section and top surface images further confirmed that the choice of substrate had no significant detrimental influence on the film growth or microstructure.

  • 32.
    Brisenmark, Lucas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Lindström, Simon
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Image based analysis on powder spreadability in powder bed additive manufacturing2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Additive manufacturing is an increasingly popular industry that has gained significant traction in the last decade. Today there exists no way to predict how a powder will spread in a powder bed additive manufacturing machine or how well it will form into thin layers. This is important because major costs can be saved by using a test that predicts the spreading behaviour of powder. This ability to be spread will be given the name spreadability.

    To test the spreadability of powder, a machine that mimicked the pushing of the powder in powder bed additive manufacturing was used. Since there exist no metric for spreadability, the study decided to attempt to quantify the spreadability with the help of image analysis. In the image analysis the area of the powders was measured, and through a comparison of the area against a bounding geometry, a measurement for spreadability can theoretically be attained. To further validate the results and simultaneously search for possible correlations, the experimental data was compared against flowability data obtained from angle of repose and Hall flowmeter.

    The results showed that the method of choice worked well for measuring the area and gave data that could be used to interpret spreadability. The data also showed what seems to be a correlation with the flowability data. While no definitive conclusions could bedrawn due to a small sample size, the collected data does seem promising for future work.

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  • 33. Cao, Y.
    et al.
    Zheng, D.
    Luo, J.
    Zhang, Fan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Wang, C.
    Dong, S.
    Ma, Y.
    Liang, Z.
    Lin, C.
    Enhanced corrosion protection by Al surface immobilization of in-situ grown layered double hydroxide films co-intercalated with inhibitors and low surface energy species2020In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 164, article id 108340Article in journal (Refereed)
    Abstract [en]

    In this work, a novel in-situ grown layered double hydroxide (LDH) film co-intercalated with inhibitors (vanadates) and low surface energy substance (laurates) was immobilized on Al substrates. A long-term monitoring of electrochemical impedance spectra (EIS) of the various samples in 3.5 wt.% NaCl solution demonstrated the synergetic protection of the intercalated two functional species. Meanwhile, the X-ray diffraction (XRD) result of the samples after immersion in NaCl solution for a long time presented the anion-exchange process between vanadates/laurates and chlorides. The synergetic effect of the two species loaded film significantly contributed to the enhanced long-term corrosion protection of aluminum.

  • 34. Caron, S.
    et al.
    Garrido, Jorge
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Setien, E.
    Harzallah, R.
    Noþ, L.
    Jerman, I.
    Röger, M.
    Sutter, F.
    Forty shades of black: A benchmark of high temperature sprayable black coatings applied on Haynes 2302020In: SOLARPACES 2019: International Conference on Concentrating Solar Power and Chemical Energy Systems, AIP Publishing , 2020, Vol. 2303, article id 0028773Conference paper (Refereed)
    Abstract [en]

    The solar receiver coating opto-thermal efficiency has a significant impact on a central receiver system thermal final system efficiency. The development of durable high solar absorptance coatings with simple application process and minimal thermal treatment can directly improve the receiver efficiency, thus reducing the levelized cost of electricity. During the past years, innovative receiver coatings for solar thermal tower plants have been developed on various substrates and tested under isothermal load at different temperature levels. In this paper, eight commercial black coating formulations are sprayed on Haynes 230 metal coupons. Solar absorptance and thermal emittance are monitored before and after isothermal exposure. Mass deviations are also measured to pinpoint any oxidation or coating outgassing. Isothermal testing is performed at 700, 750 and 800 °C in a muffle furnace for 1000 hours. After 1000 hours isothermal exposure, Coterill 750 leads the benchmark in front of Pyromark 2500, while other black coatings degrade optically. Uncoated samples oxidize significantly and appear darker than some aged black coatings.

  • 35.
    Caron, Simon
    et al.
    German Aerosp Ctr DLR, Inst Solar Res, Paseo Almeria 73, Almeria 04001, Spain..
    Garrido, Jorge
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Ballestrin, Jesus
    Plataforma Solar Almeria, CIEMAT, Carretera Senes Km 4-5, Tabernas 04200, Spain..
    Sutter, Florian
    German Aerosp Ctr DLR, Inst Solar Res, Paseo Almeria 73, Almeria 04001, Spain..
    Roger, Marc
    German Aerosp Ctr DLR, Inst Solar Res, Paseo Almeria 73, Almeria 04001, Spain..
    Manzano-Agugliaro, Francisco
    Univ Almeria, Dept Engn, CEIA3, Almeria 04120, Spain..
    A comparative analysis of opto-thermal figures of merit for high temperature solar thermal absorber coatings2022In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 154, article id 111818Article in journal (Refereed)
    Abstract [en]

    Solar thermal absorber coatings play a key role in the thermal efficiency of receivers for applications in the field of Concentrated Solar Power (CSP). The development of stable spectral selective coatings with a high solar absorptance alpha sol and a low thermal emittance epsilon th is often desired to reduce thermal losses. However, quantitative indicators describing selectivity and the trade-off between solar absorptance and thermal emittance is seldom discussed in the literature. In this review, relevant opto-thermal figures of merit are analyzed for the comparison of reference solar thermal absorber coatings, including real and ideal coatings, both black and spectral selective. The comparison is made for a temperature ranging from 25 to 1000 degrees C and for a concentration factor ranging from 20 to 1000, based on spectral data measured at room temperature from 0.25 to 20 mu m. New figures of merit are introduced, i.e. a normalized selectivity ratio Si*, a trade-off factor Ztrade-off, a normalized solar reflectance index SRI* and a peak efficiency temperature Tpeak,opt. These metrics are derived from existing figures of merit and adapted for CSP. The set of figures of merit analyzed in this review offer a complementary perspective for the detailed characterization of any coating opto-thermal performance. For solar thermal absorber coatings, thermal efficiency eta thermal and peak efficiency temperature Tpeak,opt are respectively deemed more insightful than opto-thermal efficiency eta opt-th and maximum steady-state temperature TSST,max, when comparing the relative opto-thermal performance of two coating formulations.

  • 36.
    Castillo Tapia, Pilar
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering and Fusion Science.
    Rico-Fernandez, Jose
    Northern Waves AB, S-11428 Stockholm, Sweden..
    Quevedo-Teruel, Oscar
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering and Fusion Science.
    V-Band Monolithic Additive-Manufactured Geodesic Lens Array Antenna2023In: IEEE Antennas and Wireless Propagation Letters, ISSN 1536-1225, E-ISSN 1548-5757, Vol. 22, no 10, p. 2527-2531Article in journal (Refereed)
    Abstract [en]

    Fully metallic geodesic lens antennas are popular for millimeter-wave band applications due to their simplicity, robustness, and low loss. Here, we report the experimental results of a geodesic lens array antenna, which was specifically designed to be additive-manufactured in one single piece using laser powder-bed fusion (LPBF). LPBF in aluminum alloy AlSi10Mg is able to produce high conductivity and relatively low surface roughness, so the antenna is highly directive and efficient. In addition, LPBF increases the robustness of the design since the lens array is monolithic, i.e., the risks associated with the assembly, including misalignments and undesired air gaps between pieces, are totally eliminated.

  • 37.
    Chen, Chao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Wood Chemistry and Pulp Technology.
    Bactericidal Surfaces Prepared by Femtosecond Laser Patterning and Layer-by-Layer Polyelectrolyte CoatingManuscript (preprint) (Other academic)
    Abstract [en]

    Antimicrobial surfaces are important in medical, clinical, and industrial applications, where bacterial infection and biofouling may constitute a serious threat to human health. Conventional approaches against bacteria involve coating the surface with antibiotics, cytotoxic polymers, or metal particles. However, these types of functionalization have a limited life-time and pose concerns in terms of leaching and degradation of the coating. Thus, there is a great interest in developing long-lasting and non-leaching bactericidal surfaces. To obtain a bactericidal surface, we combine μm-scale patterning of borosilicate glass surfaces by ultrashort pulsed laser irradiation and a non-leaching layer-by-layer polyelectrolyte modification of the surface. The combination of surface structure and surface charge results in an enhanced bactericidal effect against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The laser patterning and the layer-by-layer modification are environmentally friendly processes that are applicable to a wide variety of materials, which makes this method uniquely suited for fundamental studies of bacteria-surface interactions and paves the way for its applications in a variety of fields, such as in hygiene products and medical devices.

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  • 38.
    Chen, Chao
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Enrico, Alessandro
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Pettersson, Torbjörn
    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.
    Ek, Monica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Herland, Anna
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. Swedish Medical Nanoscience Center, Department of Neuroscience, Karolinska Institute, Stockholm, 17177, Sweden.
    Niklaus, Frank
    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.
    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.
    Bactericidal surfaces prepared by femtosecond laser patterning andlayer-by-layer polyelectrolyte coating2020In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 575, p. 286-297Article in journal (Refereed)
    Abstract [en]

    Antimicrobial surfaces are important in medical, clinical, and industrial applications, where bacterial infection and biofouling may constitute a serious threat to human health. Conventional approaches against bacteria involve coating the surface with antibiotics, cytotoxic polymers, or metal particles. However, these types of functionalization have a limited lifetime and pose concerns in terms of leaching and degradation of the coating. Thus, there is a great interest in developing long-lasting and non-leaching bactericidal surfaces. To obtain a bactericidal surface, we combine micro and nanoscale patterning of borosilicate glass surfaces by ultrashort pulsed laser irradiation and a non-leaching layer-by-layer polyelectrolyte modification of the surface. The combination of surface structure and surface charge results in an enhanced bactericidal effect against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. The laser patterning and the layer-by-layer modification are environmentally friendly processes that are applicable to a wide variety of materials, which makes this method uniquely suited for fundamental studies of bacteria-surface interactions and paves the way for its applications in a variety of fields, such as in hygiene products and medical devices.

  • 39.
    Chen, Jie
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Modelling of Laser Welding of Aluminium using COMSOL Multiphysics2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis presents a modelling approach of laser welding process of aluminium alloy from the thermo-mechanical point of view to evaluate the occurrence of hot cracking based on simulation results and relevant criteria. The model was created stepwise in COMSOL Multiphysics, starting with the thermal model where heat conduction of solid and liquid phase was computed. Then the CFD model was created by involving the driving forces of liquid motion in the weld pool, i.e. natural convection and Marangoni effect. Lastly, the temperature profile calculated by the CFD model was loaded into the mechanical model for computation of thermal stress and strain. The mechanical results were required in  criteria for measuring the  susceptibility of hot cracking.

    The main findings include that Marangoni effect plays a dominant role in generating the fluid flow and convective heat flux in the weld pool, thus enhancing the heat dissipation and lowering temperature in the workpiece. By contrast, such temperature reduction caused by the air convection, radiation and natural convection is negligible. The welding track further from the clamped side experiences smaller transversal residual stress, but it does not necessarily suggest higher susceptibility to hot cracking according to the applied criteria. It can be concluded judging from current results that these first models of laser welding process work satisfactorily. There is still a work to do to obtain the full maturity of this model due to its limitation and some assumptions made for simplicity.

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  • 40.
    Costa, Diogo Ribeiro
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Engineering. Westinghouse Elect Sweden AB, S-72163 Västerås, Sweden..
    Hedberg, Marcus
    Chalmers Univ Technol, Nucl Chem, S-41296 Gothenburg, Sweden..
    Lopes, Denise Adorno
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Engineering. Westinghouse Elect Sweden AB, S-72163 Västerås, Sweden..
    Delmas, Mathieu
    Archer Technicoat Ltd, High Wycombe HP12 4JD, Bucks, England..
    Middleburgh, Simon C.
    Bangor Univ, Nucl Futures Inst, Bangor LL57 1UT, Gwynedd, Wales..
    Wallenius, Janne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Power Safety.
    Olsson, Pär
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Engineering.
    Coated ZrN sphere-UO2 composites as surrogates for UN-UO2 accident tolerant fuels2022In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 567, p. 153845-, article id 153845Article in journal (Refereed)
    Abstract [en]

    Uranium nitride (UN) spheres embedded in uranium dioxide (UO2) matrix is considered an innovative accident tolerant fuel (ATF). However, the interaction between UN and UO2 restricts the applicability of such composite in light water reactors. A possibility to limit this interaction is to separate the two materials with a diffusion barrier that has a high melting point, high thermal conductivity, and reasonably low neutron cross-section. Recent density functional theory calculations and experimental results on interface interactions in UN-X-UO2 systems (X = V, Nb, Ta, Cr, Mo, W) concluded that Mo and W are promising coating candidates. In this work, we develop and study different methods of coating ZrN spheres, used as a surrogate material for UN spheres: first, using Mo or W nanopowders (wet and binder); and second, using chemical vapour deposition (CVD) of W. ZrN-UO2 composites containing 15 wt% of coated ZrN spheres were consolidated by spark plasma sintering (1773 K, 80 MPa) and characterised by SEM/FIB-EDS and EBSD. The results show dense Mo and W layers without interaction with UO2. Wet and binder Mo methods provided coating layers of about 20 µm and 65 µm, respectively, while the binder and CVD of W methods layers of about 12 µm and 3 µm, respectively.

  • 41. Cui, Y.
    et al.
    Liu, Y.
    Wang, Xi Vincent
    KTH, Centres, XPRES, Excellence in production research. KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Production Systems.
    Ding, W.
    Liu, Q.
    Research on measurement of cutting area temperature and its prediction model2018In: International Journal of Manufacturing Research, ISSN 1750-0591, Vol. 13, no 3, p. 209-226Article in journal (Refereed)
    Abstract [en]

    In this paper, the temperature measuring tool based on NiCr/NiSi thin film thermocouple is developed. 6,061 aluminium alloys is selected as the experiment object. Based on the cutting area temperature result during field test, the central composite design is utilised, which contains the parameters of cutting speed, feed rate and cutting depth. Regarding each parameter, three levels are selected and then the second-order regression equation between cutting area temperature and three cutting parameters is established. The data of experimental measurement corresponds well with the mathematical prediction, which confirms that the experimental and mathematical methods are valid in the research on cutting area temperature.

  • 42.
    da Costa, Marcus Vinicius Tavares
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. Uppsala University, Division of Applied Mechanics, Department of Materials Science and Engineering.
    Gamstedt, E. Kristofer
    Prediction of loss of barrier properties in cracked thin coatings on polymer substrates subjected to tensile strain2021In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 426, article id 127746Article in journal (Refereed)
    Abstract [en]

    Thin brittle coatings on polymer films are a potentially useful material combination for food packaging applications. The brittle coatings inevitably risk cracking when the package is converted. This strain-induced cracking leads to a loss of the key barrier properties. In design of packaging materials, it would be useful to predict the loss of the oxygen transmission rate (OTR) as a function of the applied tensile strain, which are linked by the crack opening and crack spacing in the coating. Previous works have presented a model that predicts the effect of strain on the OTR in the presence of cracks in the coating. This work uses an improved numerical model based on finite element method (FEM) to predict the oxygen permeability more accurately, especially for thin coatings with high crack densities. The numerical predictions show reasonable correspondence with experimental results for SiOx coatings. These results as well as predictions for previously tested metal-oxide coated polymer films show a significant increase in OTR at crack onset, which suggests that efforts should be made to make the coatings more ductile with higher crack onset strains if the barrier performance should be maintained in converted packages. The quantitative link from deformation over the damage state to barrier properties indicate that mechanics could provide a tool to aid the design of improved food packages with retained barrier capacity.

  • 43.
    Danielsson, Carl-Ola
    KTH, Superseded Departments (pre-2005), Mechanics.
    Continuous electropermutation using ion-exchange textile2004Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Increased levels of nitrate in ground water has made many wells unsuitable as sources for drinking water. In this thesis an ion-exchange assisted electromembrane process, suitable for nitrate removal, is investigated both theoretically and experimentally. A new ion-exchange textile material is introduced as a conducting spacer in the feed compartment of an continuous electropermutation cell. The ion-exchange textile have a high permeability and provides faster ion-exchange kinetics compared to ion-exchange resins. The sheet shaped structure of the textile makes it easy to incorporate into the cell. A report on the development of a new electro-membrane module, capable of incorporating an ion-exchange textile spacer, is presented. A theoretical study of the flow field through the electro-membrane module was performed using two different 2-D models. The calculated flow distributions provided by different proposed module designs were compared and a prototype module was produced. The flow field obtained with the prototype cell was visualised in a experimental cell with a transparent plexiglass cover. A steady-state model based on the conservation of the ionic species is developed. The governing equations on the microscopic level are presented and volume averaged to give macro-homogeneous equations. The model equations are analysed and relevant simplifications are motivated and introduced. The dimensionless parameters governing the continuous electropermutation process are identified and their influence on the process are discussed. The mathematical model can be used as a tool when optimising the process parameters and designing equipment. An experimental study that aimed to show the positive influence of using the ion-exchange textile in the feed compartment of an continuous electropermutation process is presented. The incorporation of the ion-exchange textile significantly improves the nitrate removal rate at the same time as the power consumption is decreased. A superficial solution of sodium nitrate with a initial nitrate concentration of 105 ppm was treated. A product stream with less than 20 ppm nitrate could be obtained, in a single pass mode of operation. Its concluded from these experiments that continuous electropermutation using ion-exchange textile provides an interesting alternative for nitrate removal, in drinking water production. The predictions of the mathematical model are compared with experimental results and a good agreement is obtained

  • 44.
    Delkhosh, Ehsan
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Khurshid, Mansoor
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics. Cargotec Sweden AB Bromma Conquip.
    Barsoum, I.
    Barsoum, Zuheir
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Fracture mechanics and fatigue life assessment of box-shaped welded structures: FEM analysis and parametric design2020In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 64, no 9, p. 1535-1551Article in journal (Refereed)
    Abstract [en]

    In this study, Linear Elastic Fracture Mechanics (LEFM) approach is used to evaluate the fatigue strength of a box-shaped welded structure. A parametric study is also undertaken to study the effect of various weld parameters on the fatigue strength, such as lack of weld metal penetration, load position, and plate thicknesses. FRANC3D software was adopted to obtain the stress intensity factor values for two types of full-length and intermediate crack sizes, located at the critical region of the weld of the box-shaped structure. It was concluded that the LEFM approach could capture the crack propagation from the weld root reasonably well under the given conditions and estimate residual fatigue life of the welded structures conservatively. Compared to fatigue life estimations by nominal stress method (1,714,564 cycles) or effective notch stress method (63,385 cycles), the LEFM approach can estimate the residual life more accurately. Especially for intermediate (4 mm) lack of penetration (LOP) of weld metal case (589,198 cycles) in comparison to the experiments (1,216,595 cycles). The parametric study showed that the fatigue life increases with increase in the thickness of flanges, lesser LOP in the weld root, and when load is applied more toward the center of the plate. 

  • 45.
    Du, Hongying
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Process.
    Karasev, Andrey
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Process.
    Stavlid, Nils
    Swerea KIMAB, Dept Mat & Mfg, Isafjordsgatan 28A, S-16440 Kista, Sweden..
    Bjork, Thomas
    Swerea KIMAB, Dept Mat & Mfg, Isafjordsgatan 28A, S-16440 Kista, Sweden..
    Lovquist, Simon
    AB Sandvik Coromant, Dept Verificat Prod Characterist, Mossvagen 10, S-81181 Sandviken, Sweden..
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Process.
    Using chip weight distribution as a method to define chip breakability during machining2018In: Proceedings 8th Swedish Production Symposium (SPS) / [ed] Onori, M Wang, L Wang, XV Ji, W, Elsevier BV , 2018, Vol. 25, p. 309-315Conference paper (Refereed)
    Abstract [en]

    Nowadays, the existing evaluation methods of chip breakability in industry are based on subjective visual evaluations of the chip formation during cutting or on a chip chart made after the tests. However, more sensitive methods are needed to provide more in-depth information. Thus, this study proposes a method to better evaluate the chip breakability. Based on a systematically study using the weight distribution measurement method, the results show that a great consistency and reliability to evaluate the chip breakability can be obtained. Overall, it is an objective, available and precise method to be applied in the academic and industrial research. (C) 2018 The Authors. Published by Elsevier B.V.

  • 46. Eby, F. J.
    et al.
    Narayanan, S. A.
    Abhiram, R.
    Navaneeth, M. V.
    Manu, Karthik
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Shankar, K. V.
    Nidhin, A. R.
    Influence of Solutionising Time on the Dendrite Morphology and Mechanical Behaviour of Al-Si-Mg-Ni Hypoeutectic Alloy2021In: Silicon, ISSN 1876-990X, E-ISSN 1876-9918Article in journal (Refereed)
    Abstract [en]

    The existing work deals with the development of Al-Si-Mg-Ni hypoeutectic alloys and to investigate the impact of solutionising time on their morphology and how these alloys behave mechanically. Al, Si, Mg, Ni of required weight percentages were melted into a clay graphite crucible and the mixture was poured into a permanent mould from which cast rods of ø32 mm ×156 mm in length were obtained. The cast rods were solutionised at 538 °C for 2, 4, 6, 8 and 10 h, respectively. Further, the alloys were then quenched into 30 °C water and subsequently aged at 155 °C for 12 h. It is perceived from the investigation that, as the solutionising time increases, a refinement in the grain of the developed alloy occurs and the hardness and tensile properties were seen increasing. Moreover, ductility was found to be low for the alloy solutionised at 10 h as compared to the LM25 alloy. The scanning electron images of the fractured surface revealed that the increase of solutionising time from 2 to 10 h led to a much smaller extent of the observance of dimples on the fractograph. Furthermore, the fractured surface of the alloy solutionised for 10 h depicted the presence of micro-voids, which confirms the ceasing of ductile behaviour because of longer solutionising time.

  • 47.
    Edinger, Pierre
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Kristinsson, Kristófer
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Errando-Herranz, Carlos
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Takabayashi, Alain Yuji
    Ecole Polytech Fed Lausanne, Lausanne, Switzerland..
    Sattari, Hamed
    Ecole Polytech Fed Lausanne, Lausanne, Switzerland..
    Quack, Niels
    Ecole Polytech Fed Lausanne, Lausanne, Switzerland..
    Verheyen, Peter
    Interuniv Microelect Ctr, Leuven, Belgium..
    Bogaerts, Wim
    Interuniv Microelect Ctr, Leuven, Belgium.;Univ Ghent, Ghent, Belgium..
    Gylfason, Kristinn
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Silicon photonic MEMS phase shifter with mu s time constant built on a foundry platform2021In: 2021 Conference On Lasers And Electro-Optics (CLEO), IEEE , 2021, article id STu2Q.1Conference paper (Refereed)
    Abstract [en]

    MEMS enable low power tuners in silicon photonics, but existing phase shifters lack in range, speed, and loss. We implement a 2 pi phase shifter with a 1.54 mu s time constant and 0.5 dB insertion loss in IMEC's iSiPP5OG platform.

  • 48.
    Eichenhofer, G.
    et al.
    4A‐PLASMA, Aichtalstr. 66, D‐71088 Holzgerlingen, Phone: +49 (0) 7031‐8175680.
    Fernandez, I.
    4A‐PLASMA, Aichtalstr. 66, D‐71088 Holzgerlingen, Phone: +49 (0) 7031‐8175680.
    Wennberg, Christian L.
    KTH, Centres, SeRC - Swedish e-Science Research Centre.
    Industrial use of HiPIMS and the hiP-V hiPlus technology: A review by a manufacturer2017In: Vakuum in Forschung und Praxis, ISSN 0947-076X, E-ISSN 1522-2454, Vol. 29, no 2, p. 40-44Article in journal (Refereed)
    Abstract [en]

    It has been demonstrated by several groups that HiPIMS is a state of the art tool for applying demanding coatings with superior film properties. The real industrial breakthrough for the HiPIMS-technology, has not yet happened. On the other hand, the up till now available HiPIMS-PS were mainly been up-scaled “prototypes”, far away from industrial work horses. With the hiP-V HiPIMS power system, a direct derivative of a robust power supply technology already in commercial use for public transportation systems, another milestone is set to make the HiPIMS technology go mainstream. HiPIMS is not a revolution that will make all other technologies obsolete, yet it is a very powerful complement. With a reliable, multi-functional power supply and with a rapid arc-handling, it could possibly be a start of a new era in thin film production. Just consider the possibility of etching and implantation to increase cleanliness and adhesion of the samples. Until now, most of the R&D work done in HiPIMS, has been dedicated to hard coatings and tool coatings. Here, HiPIMS is surely useful but not the expected technological breakthrough. For the future, the implementation of the new positive reverse pulse, the hiP-V hiPlus HiPIMS technology, is opening a whole new field of possible applications for i.e. nonconductive substrates where no bias can be applied. Glass and plastics can be processed with remarkable results in hardness, enhanced film properties and additionally, it is achieved at lower substrate temperatures. It has been a slow start for HiPIMS, but the future looks bright.

  • 49.
    Ekblad, Jonas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Civil and Architectural Engineering Laboratory. NCC.
    Lundström, Robert
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Civil and Architectural Engineering Laboratory. NCC.
    Karlsson, Robert
    Trafikverket.
    Valtonen, Jarkko
    Aalto University .
    Impact on rutting from introduction of increased axle loads in Finland2020In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268XArticle in journal (Refereed)
    Abstract [en]

    In 2013, Finland introduced legislation increasing gross vehicle weights (GVW) on a number of trucks. Since the actual impact on road damage is nearly impossible to quantify in advance, the present analysis of road surface measurements is intended to provide knowledge regarding the impact on road damage. Rutting is influenced by many conflated phenomena. To indicate and capture the effect on road damage due to the new maximum GVW for certain truck- and trailer combinations, the analysis follows two different but mutually supporting lines of reasoning, empirical and theoretical, respectively. Analysis of measured rut depth is supported by theoretical calculations. Theoretical findings clearly indicate that the relative increase in road damage induced by higher GVW is larger than the increase in relative payload capacity. There was a rapid fleet shift towards heavier trucks after 2013, and statistical (empirical) analysis of road surface measurements shows an increase in rutting after this introduction.

  • 50.
    Elhami Nik, Farzad
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. Department of Electronics, Information and Bioengineering, Politecnico di Milano.
    Matthiesen, Isabelle
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Herland, Anna
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. AIMES, Department of Neuroscience, Karolinska Institute.
    Winkler, Thomas
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Low-Cost PVD Shadow Masks with Submillimeter Resolution from Laser-Cut Paper2020In: Micromachines, E-ISSN 2072-666X, Vol. 11, no 7, article id 676Article in journal (Refereed)
    Abstract [en]

    We characterize an affordable method of producing stencils for submillimeter physical vapor deposition (PVD) by using paper and a benchtop laser cutter. Patterning electrodes or similar features on top of organic or biological substrates is generally not possible using standard photolithography. Shadow masks, traditionally made of silicon-based membranes, circumvent the need for aggressive solvents but suffer from high costs. Here, we evaluate shadow masks fabricated by CO2 laser processing from quantitative filter papers. Such papers are stiff and dimensionally stable, resilient in handling, and cut without melting or redeposition. Using two exemplary interdigitated electrode designs, we quantify the line resolution achievable with both high-quality and standard lenses, as well as the positional accuracy across multiple length scales. Additionally, we assess the gap between such laser-cut paper masks and a substrate, and quantify feature reproduction onto polycarbonate membranes. We find that ~100 µm line widths are achievable independent of lens type and that average positional accuracy is better than ±100 µm at 4”-wafer scale. Although this falls well short of the micron-size features achievable with typical shadow masks, resolution in the tenths to tens of millimeters is entirely sufficient for applications from contact pads to electrochemical cells, allowing new functionalities on fragile materials.

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