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  • 451.
    Alemani, Mattia
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Tribologi.
    On the scaling effects of measuring disc brake airborne particulate matter emissions – a comparison of a pin-on-disc tribometer and an inertia dynamometer bench under dragging conditionsManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    An important contributor to non-exhaust emissions in urban areas is airborne particulate matter originating from brake systems. A well-established way to test such systems in industry is to use Inertia dynamometer benches; although they are quite expensive to run. Pin-on-disc tribometers, on the other hand, are relatively cheap to run, but simplify the real system. The literature indicates promising correlations between these two test stands with regard to measured airborne number distribution. Recent studies also show a strong dependency between the airborne number concentration and the disc temperature. However, a direct comparison that also takes into account temperature effects is missing. The aim of this paper is, therefore, to investigate how the transition temperature is affected by the different test scales, under dragging conditions, and the effects on total concentration and size distribution. New and used low-steel pins/pads were tested against cast iron discs/rotors on both the aforementioned test stands, appositely designed for particulate emission studies. A constant normal load and constant rotational velocity were imposed in both test stands. Results show that a transition temperature can always be identified. However, it is influenced by the test scale and the frictional pair status. Nevertheless, emissions are assessed similarly when an equivalent frictional pair status is analysed (e.g. run-in). Further investigations for fully run-in samples on the pin-on-disc should be performed in order to finally assess the possibility of using the tribometers for the initial assessment of different friction materials.

  • 452.
    Alemani, Mattia
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Tribologi.
    Particle emissions from car brakes: The influence of contact conditions on the pad-to-rotor interface2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Due to their adverse health effects emissions have been regulated for over three decades. Brake wear particulate matter is the most important non-exhaust source, however current knowledge is mainly limited to observational studies. This thesis aims to investigate relations between the brake system contact conditions and the related emissions on a model scale; validate the results on a component level; and understand to what extent they are significant on a full-scale.

    Paper A investigates the influence of nominal contact pressure on a model scale. Results show that higher pressure corresponds to higher emissions

    Paper B investigates the influence of the nominal contact pressure, for different friction materials, on a model scale. A temperature threshold, responsible for a relevant emission increase, is identified.

    Paper C investigates particle characteristics and wear mechanisms for different nominal contact pressures, on a model scale. Results show an enhanced tribo-layer at higher pressure levels.

    Paper D investigates the influence of brake system conditions on emissions, on a model scale. Results show that frictional power is the most important parameter. A transition temperature independent of the contact condition is identified.

    Paper E investigates similarities occurring on a component scale and a model scale in terms of emissions. Results show a promising correlation, and the possibility of using a pin-on-disc tribometer for R&D activities.

    Paper F investigates analogies occurring on a component scale and a model scale, in terms of friction performance, fictional surface and chemical composition. Results show similar phenomena occurring for the two test stands.

    Paper G analyses real brake system working conditions in a urban environment defining, by means of an inertia dyno bench, the related emissions. Results reveal emission factors compliant to EURO6 and EURO2 regulations, in terms of number and mass, respectively.

    Fulltekst (pdf)
    fulltext
  • 453. Alemani, Mattia
    et al.
    Gialanella, S.
    Straffelini, G.
    Ciudin, R.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Perricone, G.
    Metinoz, I.
    Dry sliding of a low steel friction material against cast iron at different loads: Characterization of the friction layer and wear debris2017Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 376-377, s. 1450-1459Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pin-on-disc testing was used to investigate the sliding behavior and the wear products of a low-steel friction material against a cast iron disc at different applied loads, to investigate the effect of the temperature rise induced by frictional heating. The testing rig was operated in a clean chamber with a purified incoming air flux. The outgoing flux carries the wear particles to an impactor that counted and sorted them by average diameter and weight. At increasing applied loads, corresponding to a proportional increase of the pin-disc contact temperature, the coverage of both the pin and disc surface by a friction layer was found to increase too. The relevant X-Ray diffraction patterns revealed the presence of a large amount of graphite and different compounds originating from the friction material and from the counterface disc, mainly iron oxides, as concerns this latter. After the test at the lowest investigated load, i.e., 1 kg, the disc worn surface exhibited abrasive grooves and a discontinuous friction layer mainly made of compacted iron oxide particles. After the test at higher loads, i.e., 5 and 7 kg, the disc surface was covered by a compact friction layer. As concerns the friction layer on the pins, most of the ingredients from the friction material were detected, in association with the iron oxides from the disc. These results can be interpreted in terms of the temperature stability range of the phenolic resin used as a binder of the friction material. The characterization of the collected airborne wear debris showed that the particles produced by the low temperature (i.e., low load) test were mostly equiaxed; whereas those produced by the high temperature (i.e., high loads) tests, predominantly displayed a plate-like morphology. The mechanisms of their formation in relation to the characteristics of the friction layers are illustrated and discussed.

  • 454.
    Alemani, Mattia
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Tribologi.
    Gialanella, Stefano
    Straffellini, Giovanni
    Ciudin, Rodica
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Tribologi.
    Perrcone, Guido
    KTH.
    Metinoz, Ibrahim
    Dry sliding of a low steel friction material against cast iron at different loads: characterization of the friction layer and wear debrisManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Pin-on-disc testing was used to investigate the sliding behavior and the wear products of a low-steel friction material against a cast iron disc at different applied loads, to investigate the effect of the temperature rise induced by frictional heating. The testing rig was operated in a clean chamber with a purified incoming air flux. The outgoing flux carries the wear particles to an impactor that counted and sorted them by average diameter and weight. At increasing applied loads, corresponding to a proportional increase of the pin-disc contact temperature, the coverage of both the pin and disc surface by a friction layer was found to increase too. The relevant X-Ray diffraction patterns revealed the presence of a large amount of graphite and different compounds originating from the friction material and from the counterface disc, mainly iron oxides, as concerns this latter. After the test at the lowest investigated load, i.e., 1 kg, the disc worn surface exhibited abrasive grooves and a discontinuous friction layer mainly made of compacted iron oxide particles. After the test at higher loads, i.e., 5 and 7 kg, the disc surface was covered by a compact friction layer. As concerns the friction layer on the pins, most of the ingredients from the friction material were detected, in association with the iron oxides from the disc. These results can be interpreted in terms of the temperature stability range of the phenolic resin used as a binder of the friction material. The characterization of the collected airborne wear debris showed that the particles produced by the low temperature (i.e., low load) test were mostly equiaxed; whereas those produced by the high temperature (i.e., high loads) tests, predominantly displayed a plate-like morphology. The mechanisms of their formation in relation to the characteristics of the friction layers are illustrated and discussed.

  • 455. Alemani, Mattia
    et al.
    Nosko, Oleksii
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Metinoz, Ibrahim
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    A study on emission of airborne wear particles from car brake friction pairs2015Inngår i: SAE International Journal of Materials & Manufacturing, ISSN 1946-3979, E-ISSN 1946-3987, Vol. 9, nr 1, s. 147-157, artikkel-id 2015-01-2665Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The emission of airborne wear particles from friction material / cast iron pairs used in car brakes was investigated, paying special attention to the influence of temperature. Five low-metallic materials and one non-asbestos organic material were tested using a pin-on-disc machine. The machine was placed in a sealed chamber to allow airborne particle collection. The concentration and size distribution of 0.0056 to 10 μm particles were obtained by a fast mobility particle sizer and an optical particle sizer. The temperature was measured by a thermocouple installed in the disc. The experiments show that as the temperature increases from 100 to 300 °C the emission of ultrafine particles intensifies while that of coarse particles decreases. There is a critical temperature at which the ultrafine particle emission rate rises stepwise by 4 to 6 orders of magnitude. For the friction pairs investigated, the critical temperature was found to be between 165 and 190 °C. Below the critical temperature, fine particles outnumber coarse and ultrafine particles, although coarse particles make up the bulk of the particulate matter mass. The friction pairs differ in the ultrafine particle emission rate by 1 to 2 orders of magnitude. Above the critical temperature, ultrafine particles constitute almost 100% of the total particle number and their relative mass contribution can exceed 50%. Analysis of the particle size distributions revealed peaks at 0.19-0.29, 0.9 and 1.7 μm. Above the critical temperature, one more peak appears in the ultrafine particle range at 0.011-0.034 μm.

  • 456. Alemani, Mattia
    et al.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Tribologi.
    Perricone, Guido
    Söderberg, Anders
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Wahlström, Jens
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Ciotti, Alessandro
    A study on the load level influence on particulate matter emissions from the sliding contact between a low steel friction material and cast iron2015Konferansepaper (Fagfellevurdert)
  • 457. Alemani, Mattia
    et al.
    Perricone, Guido
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Söderberg, Anders
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Wahlström, Jens
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Ciotti, Alessandro
    A proposed dyno bench test cycle to study particle emissions from disc brakes2014Konferansepaper (Fagfellevurdert)
  • 458.
    Alemani, Mattia
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.). Brembo S.p.A, Stezzano, Italy.
    Wahlström, Jens
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Tribologi.
    Matějka, Vlastimil
    Metinöz, Ibrahim
    Söderberg, Anders
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Perricone, Guido
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.). Brembo S.p.A, Stezzano, Italy.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Tribologi.
    Scaling effects of measuring disc brake airborne particulate matter emissions – A comparison of a pin-on-disc tribometer and an inertia dynamometer bench under dragging conditions2018Inngår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305XArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An important contributor to non-exhaust emissions in urban areas is airborne particulate matter originating from brake systems. A well-established way to test such systems in industry is to use inertia dynamometer benches; although they are quite expensive to run. Pin-on-disc tribometers, on the other hand, are relatively cheap to run, but simplify the real system. The literature indicates promising correlations between these two test stands with regard to measured airborne number distribution. Recent studies also show a strong dependency between the airborne number concentration and the disc temperature. However, a direct comparison that also takes into account temperature effects is missing. The aim of this paper is, therefore, to investigate how the transition temperature is affected by the different test scales, under dragging conditions, and the effects on total concentration and size distribution. New and used low-steel pins/pads were tested against cast iron discs/rotors on both the aforementioned test stands, appositely designed for particulate emission studies. A constant normal load and constant rotational velocity were imposed in both test stands. Results show that a transition temperature can always be identified. However, it is influenced by the test scale and the frictional pair status. Nevertheless, emissions are assessed similarly when an equivalent frictional pair status is analysed (e.g. run-in). Further investigations for fully run-in samples on the pin-on-disc should be performed in order to finally assess the possibility of using the tribometers for the initial assessment of different friction materials.

  • 459.
    Alemani, Mattia
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Tribologi.
    Wahlström, Jens
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Tribologi.
    ON THE INFLUENCE OF CAR BRAKE SYSTEM PARAMETERS ON PARTICULATE MATTER EMISSIONSManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The influence of car brake system parameters on particulate matter emissions was investigated using a pin-on-disc tribometer. Samples from a low-steel friction material and a cast iron disc were tested for different sliding velocities, nominal contact pressures and frictional powers. Disc temperatures were also measured. Their impact on total concentration, size distribution, particle coefficient and transition temperature was analysed. Results show that frictional power is the most significant brake system parameter. However, temperature, as a response parameter, is the most influential, inducing a shift towards the ultrafine particulate fraction and raising emissions. A transition temperature, independent of the system parameters, was identified.

  • 460.
    Alemani, Mattia
    et al.
    KTH.
    Wahlström, Jens
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinkonstruktion (Avd.). KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement. KTH, Skolan för industriell teknik och management (ITM), Tillämpad maskinteknik (KTH Södertälje). KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Tribologi.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Tribologi.
    On the influence of car brake system parameters on particulate matter emissions2018Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 396, s. 67-74Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The influence of car brake system parameters on particulate matter emissions was investigated using a pin-on-disc tribometer. Samples from a low-steel friction material and a cast iron disc were tested for different sliding velocities, nominal contact pressures and frictional powers. Disc temperatures were also measured. Their impact on total concentration, size distribution, particle coefficient and transition temperature was analysed. Results show that frictional power is the most significant brake system parameter. However, temperature, as a response parameter, is the most influential, inducing a shift towards the ultrafine particulate fraction and raising emissions. A transition temperature, independent of the system parameters, was identified.

  • 461.
    Alemseged, Sador
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Hållbar produktionsutveckling (ML).
    Saleem, Nooraldeen
    KTH, Skolan för industriell teknik och management (ITM), Hållbar produktionsutveckling (ML).
    BTPX 305 separator2019Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    This thesis analyzes BTPX 305, a biotech separator developed by Alfa Laval. It focuses on a problem found in the vertical drive where the machine's vibration absorber and damper take place. Today the machine is experiencing vibration above the normal levels, and the product that the machine usually separates is very sensitive to vibration. Therefore, the damping mechanism in the machine needs to be serviced often because of wear in the damping mechanism. In the report, a variety of methods are used, TIPS (the Theory of Inventive Problem Solving) for example are used to model and describe the problem in more detail, and internal/external research is done to possibly find inspiration from other machines that have solutions to similar problems. Solution ideas were generated in brainstorming sessions that were mostly inspired by the information gathered from both the internal and external sources. The concepts were then adapted to then become a solution proposal to the problem. With the help of a priority matrix, it was decided which of the concepts should be considered reasonable as a solution proposal. A couple of experiments were conducted on the concepts that were further taken from the priority matrix to ensure that the theory works in practice.

    Fulltekst (pdf)
    fulltext
  • 462.
    Alenius, Emma
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strömningsakustik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Sound Generating Flow Structures in a Thick Orifice Plate Jet2014Inngår i: Progress in Turbulence V: Proceedings of the iTi Conference in Turbulence 2012, Cham, Switzerland: Springer, 2014, s. 201-204Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The aim of thiswork is to study sound generating flowstructures in a thickcircular orifice plate jet, placed in a circular duct. Large eddy simulations (LES)are performed for two jet Mach numbers, 0.4 and 0.9. Characteristic frequenciesin the flow, and their corresponding flow structures, are identified with dynamicmode decomposition (DMD). The results show that a tonal noise is generated atfrequencies where the jet displays strong ring vortices, in the plane wave range.The main sound generating mechanisms seems to be a fluctuating mass flow at theorifice opening and a fluctuating surface force at the plate sides, caused by the ringvortices. The frequencies are believed to be chosen, and strengthened, by a feedbackmechanism between the orifice in- and outlet.

  • 463.
    Alenius, Emma
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strömningsakustik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Åbom, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strömningsakustik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Fuchs, Laszlo
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Large eddy simulations of acoustic-flow interaction at an orifice plate2015Inngår i: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 345, s. 162-177Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The scattering of plane waves by an orifice plate with a strong bias flow, placed in a circular or square duct, is studied through large eddy simulations and dynamic mode decomposition. The acoustic-flow interaction is illustrated, showing that incoming sound waves at a Strouhal number of 0.43 trigger a strong axisymmetric flow structure in the orifice in the square duct, and interact with a self-sustained axisymmetric oscillation in the circular duct orifice. These structures then generate a strong sound, increasing the acoustic energy at the frequency of the incoming wave. The structure triggered in the square duct is weaker than that present in the circular duct, but stronger than structures triggered by waves at other frequencies. Comparing the scattering matrix with measurements, there is a good agreement. However, the results are found to be sensitive to the inflow, where the self-sustained oscillation in the circular duct simulation is an artefact of an axisymmetric, undisturbed inflow. This illustrates a problem with using an undisturbed inflow for studying vortex-sound effects, and can be of interest when considering musical instruments, where the aim is to get maximum amplification of specific tones. Further, it illustrates that at the frequency where an amplification of acoustic energy is found for the orifice plate, the flow has a natural instability, which is suppressed by non-axisymmetry and incoming disturbances.

  • 464.
    Alenius, Emma
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strömningsakustik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Åbom, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strömningsakustik.
    Fuchs, Laszlo
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    LES of Acoustic-Flow Interaction at an Orifice Plate2012Inngår i: 18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference), 2012Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The scattering of plane waves by a thick orifice plate, placed in a circular or square duct with flow, is studied through Large Eddy Simulation. The scattering matrix is computed and compared to measurements, showing reasonably good agreement except around one frequency ($St \approx 0.4$). Here a stronger amplification of acoustic energy is observed in the circular duct simulations than in the measurements and the square duct simulations. In order to improve the understanding of the interaction between an incoming wave, the flow, and the plate, a few frequencies are studied in more detail. A Dynamic Mode Decomposition is performed to identify flow structures at significant frequencies. This shows that the amplification of acoustic energy occurs at the frequency where the jet in the circular duct has an axisymmetric instability. Furthermore, the incoming wave slightly amplifies this instability, and suppresses background flow fluctuations.

  • 465.
    Alenius, Emma
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strömningsakustik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Åbom, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strömningsakustik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Fuchs, Laszlo
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx).
    Scattering of Plane Waves by a Constriction2011Inngår i: Proceedings of ASME Turbo Expo 2011, Vol 7, Parts A-C, American Society Of Mechanical Engineers , 2011, s. 1043-1052Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Liner scattering of low frequency waves by an orifice plate has been studied using Large Eddy Simulation and an acoustic two-port model. The results have been compared to measurements with good agreement for waves coming from the downstream side. For waves coming from the upstream side the reflection is over-predicted, indicating that not enough of the acoustic energy is converted to vorticity at the upstream edge of the plate. Furthermore, the sensitivity to the amplitude of the acoustic waves has been studied, showing difficulties to simultaneously keep the amplitude low enough for linearity and high enough to suppress flow noise with the relatively short times series available in LES.

  • 466.
    Alevanau, A. Y.
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Kuznechik, O. P.
    Vyhoniailo, O. I.
    Prospective Engineering Applications of Dynamic Transfer Processes Possessing the Self-Organized Fractal Interfaces2013Inngår i: Journal of Engineering, ISSN 2314-4904, E-ISSN 2314-4912, Vol. 2013, artikkel-id 310748Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    General formulation of practically applicable fundamental approach for development of engineering applications in systems with dynamically appearing and disappearing fractal structures is proposed. The approach is illustrated on the low-temperature pyrolysis of butane/propane mixture being pumped via the liquid tin and bismuth alloy preserved at the temperature 200 ± 20°C in the U-shaped test glass. Other prospective engineering applications of the approach are proposed on the base of analysis of selected experiments described in literature.

  • 467.
    Alevanau, Aliaksandr
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Study of pyrolysis and gasification of biomass from the self-organization perspective2015Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis focuses on the analysis of kinetics of i) low-temperature pyrolysis of gaseous hydrocarbons, ii) high-temperature steam gasification of char of wood pellets (>700oC), iii) high temperature pyrolysis of straw pellets in an atmosphere of argon and steam, and iv) high temperature pyrolysis of slices of transversally cut wooden sticks. The results of the kinetic measurements in the high-temperature cases are approximated using a least-square based optimization software, which was specially developed to analyse kinetics prone for deviation from the Arrhenius law.In the thesis a general analysis of the researched materials and kinetics of their pyrolysis and gasification is presented from the self-organization perspective. The energy transfer phenomena in both the pyrolysis and gasification processes of biomass are discussed with an emphasis on an analysis of basic phenomena involving the self-organized dynamics on fractal structures in the chosen biomass samples.

    Fulltekst (pdf)
    Alevanau_Thesis
  • 468.
    Alevanau, Aliaksandr
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Study of the Apparent Kinetics of Biomass Gasification Using High-Temperature Steam2010Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Among the latest achievements in gasification technology, one may list the development of a method to preheat gasification agents using switched ceramic honey combs. The best output from this technology is achieved with use of water steam as a gasification agent, which is heated up to 1600 °C. The application of these temperatures with steam as a gasification agent provides a cleaner syngas (no nitrogen from air, cracked tars) and the ash melts into easily utilised glass-like sludge. High hydrogen content in output gas is also favourable for end-user applications.Among the other advantages of this technology is the presumable application of fixed-bed-type reactors fed by separately produced and preheated steam. This construction assumes relatively high steam flow rates to deliver the heat needed for endothermic reactions involving biomass. The biomass is to be heated uniformly and evenly in the volume of the whole reactor, providing easier and simpler control and operation in comparison to other types of reactors. To provide potential constructors and exploiters of these reactors with the kinetic data needed for the calculations of vital parameters for both reactor construction and exploitation, basic experimental research of high-temperature steam gasification of four types of industrially produced biomass has been conducted.Kinetic data have been obtained for straw and wood pellets, wood-chip charcoal and compressed charcoal of mixed origin. Experiments were conducted using two experimental facilities at the Energy and Furnace Division of the Department of Material Science and Engineering (MSE) at the School of Industrial Engineering and Management (ITM) of the Royal Institute of Technology (KTH) and at the Combustion Laboratory of the Mechanical Engineering Department of the University of Maryland (UMD), USA.

    The experimental facility at the Energy and Furnace Division has been improved with the addition of several constructive elements, providing better possibilities for thermo-gravimetric measurements.The obtained thermo-gravimetric data were analysed and approximated using several models described in the literature. In addition, appropriate software based on the Scilab package was developed. The implementation of the isothermal method based on optimisation algorithms has been developed and tested on the data obtained under the conditions of a slow decrease of temperature in experiments with the char gasification in small-scale experimental facilities in the Energy and Furnace Division.The composition of the gases generated during the gasification of straw and wood pellets by high-temperature steam has been recorded and analysed for different experimental conditions.

     

    Fulltekst (pdf)
    FULLTEXT02
  • 469.
    Alevanau, Aliaksandr
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Ahmed, Islam
    Gupta, Ashwani K.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Blasiak, Wlodzimierz
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Parameters of high temperature steam gasification of original and pulverised wood pellets2011Inngår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 92, nr 10, s. 2068-2074Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Experiments on gasification of chars obtained from original and pulverised wood pellets were conducted in atmosphere of water steam and nitrogen under temperatures of 800, 900 and 950 degrees C. Molar flow rates of carbon containing product gases were measured and approximated using different models with respect to extents of carbon conversion in char of the pellets. Comparison of the random pore, grain and volumetric models revealed the best applicability for approximations of the random pore model. Apparent activation energies obtained as a result of application of the models to the data from experiments with char of original pellets were higher in comparison to those of pulverised pellets, except for a grain model. Approximations under 800 degrees C showed relatively big deviations from experimental data on the beginning of char gasification. This is attributed to catalytic effects from alkali metals in the pellets.

  • 470.
    Alevanau, Aliaksandr
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Donaj, Pawel
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Blasiak, Wlodzimierz
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Applicability of Scaling Approach for Analysis of Pyrolysis and Gasification of Porous Structures Composed of Solid Fuel Particles2012Inngår i: ISRN Mechanical Engineering, ISSN 2090-5122, E-ISSN 2090-5130, artikkel-id 207464Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Experimental research on the pyrolysis and gasification of randomly packed straw pellets was conducted with an emphasis on the reactive properties of the shrinking porous structure of the pellets. The apparent kinetics of such pyrolysis was approximated by the random pore, grain, and volumetric models. The best approximation results were obtained with the grain and random pore models. The self-organized oscillations of the pellet conversion rate during pyrolysis were observed. Two complementary explanations of the phenomenon are proposed.

    Fulltekst (pdf)
    fulltext
  • 471.
    Alevanau, Aliaksandr
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Donaj, Pawel
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Blasiak, Wlodzimierz
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    High temperature steam gasification of straw pelletsManuskript (preprint) (Annet vitenskapelig)
  • 472.
    Alevanau, Aliaksandr
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Ersson, Mikael
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Kantarelis, Efthymios
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Kuznechik, Olgerd
    Belarussian State University.
    Vyhoniailo, Oleksandr
    Mechanically assisted low temperature pyrolysis of hydrocarbons2014Inngår i: Proceedings of the XVII International Conference Foundations & Advances in Nonlinear Science, September 29 - October 3, Minsk 2014, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We report experimental setups and conditions leading to pyrolysis (cracking) of such gaseous hydrocarbons as methane, mixed propane and butane, at the temper-atures of the heater below 200oC. The process was mechanically assisted by putting the substances being decomposed into a dynamic interaction with the tin and bismuth alloy. The alloy had periodically changing phase state thus creating fractal interfaces between its surface and the gases. Interaction of the gases with mechanically produced fractal surfaces of the alloy made possible gas decomposition even at lower temperatures of the heater (150oC). At this temperature the heater couldn't melt the alloy in the heated volume with the gas.

    Fulltekst (pdf)
    fulltext
  • 473.
    Alevanau, Aliaksandr
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Kantarelis, Efthymios
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Blasiak, Wlodzimierz
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Study of the effects of gaseous micro-expansion on the efficiency of convective heat transfer during pyrolysis2013Inngår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 106, s. 253-261Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Measurements of temperature in the proximity of wood pellets (8 mm diameter) and thin wooden stick slices (5 cm diameter and 5 mm thickness) were conducted to estimate the effects of mixing between the evolving volatiles and hot steam (T > 700°C) flowing around the particles. Measurements of mass loss of the slices were conducted to estimate the apparent kinetic parameters of their pyrolysis. A simple kinetic model of the process (type II by Pyle and Zaror (1984) [20]) was investigated. The experiments showed a plateau-like part in the graphs of temperature measured in the proximity to the samples. The existence of this plateau-like part agrees with the general data of calorimetric measurements of pyrolysis, which show extensive energy consumption in the beginning of an active production of volatiles. A hypothesis regarding feedback on the process due to the micro-expansion and mixing of volatiles in the convective boundary layer is discussed.

  • 474.
    Alevanau, Aliaksandr
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Blasiak, Wlodzimierz
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Kuznechik, O.
    Vyhoniailo, O.
    Prospective side effects of the heat and mass transfers in micro-porous structure of char during intermediate and final stages of the high-temperature pyrolysis2013Inngår i: Nonlinear Phenomena in Complex Systems, ISSN 1561-4085, E-ISSN 1817-2458, Vol. 16, nr 3, s. 287-301Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The general problem of a decrease of activation energy for reactions of thermal decomposition in ligno-cellulosic materials in the end of the high-temperature pyrolysis has been discussed. Experiments emphasizing the differences between the starting, intermediate and final stages of the process were conducted. A hypothesis to solve the problem from the point of view of a fundamental fractal theory was formulated. The conclusions of the discussions related to the hypothesis gave a description of new experiments to prove the fundamental theory on diffusion processes with naturally or artificially created conditions for self-organization.

  • 475.
    Alex, Roger
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Concept development of framework or interactive exhibition2010Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This Master Thesis was started with

    The Interactive Institutes's department for Art &

    Technology

    . The project was to further develop a concept they had created for subscription exhibitions. The core idea of the concept was centered around a computer screen that was to show an interactive video artwork that the user could interact with by rotating the screen around the display stand.

    The goal of the project was to develop their concept to such a degree that it would be possible to manufacture a finished product. Initially this included both the development of a framework for the construction as well as the design of an exterior shell. After initial research and consultation

    with the commissioner it was however decided to shift the focus of the project to the development of the framework. This so that the exterior design in a later stage could be created to suit the profile of multiple customers and thus make for a more versatile solution. The desired result of the work was to contain the documentation needed for construction and to enable the concept for an external designer to come in at a later stage and create the exterior shell.

    The developed concept consisted of three main parts, first the main body that enabled the height adjusting function to enable a hide range of users, then the head that contains the rotary function as well as being prepared to house the needed electronic components and lastly the areas that have been prepared for the attachment of an exterior shell. This way an almost completely finished solution was created. The finished result consists of a list of parts for material and components as well as technical drawings for the manufacture of desired parts and assembly.

    Future work could include the manufacture of a prototype so that any problems can be isolated and rectified. With the aid of a prototype it would also be easier to bring in users to asses their reactions to the product and also to gauge how different designs would alter the user experience.

    With time permitting it could also be of interest to delve into related areas that could expand the usability of the concept.

    Fulltekst (pdf)
    Roger Alex
  • 476.
    Alexandersson, Gabriella
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi.
    Treatment of Waste Water from Coke Production Feasibility Study of Huaxi Jiohua Ltd, Wuhai,2007Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    China is the most populous country in the world and has an increasing economy. A growingeconomy enhances the electricity requirement, product demands and so on, which affects both the surrounding environment but also the global environment.Wuhai is an industrial city and the most polluted city in Inner Mongolia, China. Numerous amounts of the industries are lacking in the emission treatment and the PM10 is more then 10 times the allowed amount of European Union.This master thesis is a part of a bigger project, a corporation between IVL Swedish Environmental Research Institute Ltd and Environmental Protection Bureau in Wuhai.The Coke Company Huaxi Jiohua Ltd. was founded 1992, and has a producing capability of300.000 tons coke per year. The treatment station is a model of an ASP, without a sludge recycling and a sludge thickener instead of sedimentation basin. The treatment efficiency is failing in phenol removal.The aim of this thesis is to perform a feasible study of the wastewater treatment methods foran improvement of the separation of pollutions in coke wastewater and to give a proposal forimprovement of energy efficiency from wastewater treatment.Treatment efficiency of methods such as A2/O, A/O, SBR, and ASP was taken inconsideration.Due to the lack of basic treatment, a first suggestion is to optimize the biological parameters,and introduce sludge recycling to the system together with either a following sedimentationpool or a MBBR as a pre-treatment step.To gain energy from the wastewater treatment station, a replacing of the current aerator system in the aeration unit to fine bubble diffusers and introduce a heat exchanger in the cooling of gas step could be done.

    Fulltekst (pdf)
    FULLTEXT01
  • 477.
    Alexandersson, Robert
    et al.
    KTH, Skolan för industriell teknik och management (ITM).
    Tran, Stephan
    KTH, Skolan för industriell teknik och management (ITM).
    Change in heating costs for different renovation alternatives of a million-housing program building2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In 2014 the network for energy efficient multi-residential buildings, BeBo, finished a project called “Ett hus, fem möjligheter” (“One building, five opportunities”). The purpose was to provide insight into and a comparison of five different renovation alternatives for an existing building from the million-housing program, resulting in a decrease in energy use by at least half. Since the completion of this project the district heating tariffs have undergone deeper differentiation and added complexity, with several price components that make up the total DH (district heating) price, such as power price, energy price and return temperature discount or fee. Meanwhile, average electricity prices in Sweden have increased. The impacts of these price developments on the energy cost savings of the five alternatives in “Ett hus, fem möjligheter” have not been investigated.

    Due to this, the consultant company WSP, which is tasked with coordinating BeBo, requested an investigation on what change there has been in heating costs for the renovation alternatives from “Ett hus, fem möjligheter” between 2014 and 2019 in the city of Stockholm, with focus on Stockholm and Solna municipality. Energy demand for the building and its alternatives was simulated and entered into an energy cost calculation tool called PRISMO developed by BeBo in 2017, together with energy price structures for Stockholm municipality (from Stockholm Exergi for DH and from Ellevio for electricity) and Solna municipality (from Norrenergi for DH and from Vattenfall Eldistribution AB for electricity).

    The results showed a change in energy cost for all alternatives in all scenarios. In Stockholm municipality, both district heating and electricity cost has increased for all alternatives. DH cost has increased by between 15% and 18% for the base building and all alternatives using only DH (alternatives 1 and 2). In alternatives with combined DH and electricity the DH cost has increased by about 24% where DH is used for domestic hot water and peak heat load, and by slightly more than 30% where DH is used for peak heat load only. Alternative 5.2, with DH for peak load and where DH power demand is low due to higher heat pump power, sees the highest increase in DH cost, being 49%. This is despite lowered energy cost, primarily due to significant increase in the power cost and lowered return temperature bonus. Electricity cost has increased by about 30%. The buildings with a higher share of power cost compared to energy cost have seen a larger increase between the years, and high electricity demand has also contributed to a larger cost increase.

    In Solna municipality the DH price structures did not change considerably between 2014 and 2019 and as such the DH costs see only small changes. Most of this change in DH cost is due to a change in power price coming to favor buildings with power demand above 96 kW, with small contribution from a minor energy price reduction. Return temperature malus did not change between 2014 and 2019. The DH cost has decreased for all applicable alternatives by at most 2%, except for alternatives 1 and 5.2, where it has increased by 0.3% and remained the same, respectively, due to higher relative power cost for their lower power levels. Similarly to in Stockholm municipality, the electricity costs have increased significantly, by about 35%. Alternatives partially or fully heated by electricity have all shown an increase, which is lesser the higher the extent of DH use is. Accordingly, the largest increase in energy cost is found for the fully electrified alternative 5.1

    . Energy cost changes obtained in this study were compared with changes in energy cost reported by the Nils Holgersson Gruppen, a reporting group created by various housing companies and associations in the industry. The comparisons show that energy cost changes are aligned for both DH and electricity in Solna municipality and for electricity in Stockholm municipality. However, the cost change for DH in Stockholm municipality in this study is about +15-18% for DH-only alternatives, whereas this change is reported as -2% (between 2014 and 2018) by Nils Holgersson Gruppen for their DH-only reference building. Implementing Nils Holgersson’s reference building energy demand data in PRISMO together with DH price structures of 2014 and 2019 for the same municipality shows that there is an increase in DH cost by 8.2% over this time period, excluding return temperature discounts or fees, as return temperature is not considered in the Nils Holgersson Report.

    Fulltekst (pdf)
    fulltext
  • 478.
    ALEXANDRAKIS, VASSILIS
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    A participatory approach to the development of specifications for a 3D puzzle for visually impaired and sighted users2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Det finns begränsad tillgång till pussel för personer med synfel (inklusive blinda personer). För att undersöka behovet av potentiella användare i 3D kartpussel och identifiera deras preferenser, behov och krav, användes en kvalitativ metod som på engelska kallas ”participatory design”. Projektet utfördes i Kreta och alla deltagare kom från ön. Då Icke-standardiserade subjekt användes i forskningsprojektet användes lämpliga tillgängliga metoder och kommunikationsvägar för att anpassa studien för denna grupp. Stor vikt lades ner på bakgrundsstudier, inklusive intervjuer med experter och undersökning av befintligt material inom detta ämne.  För att underlätta förståelsen av konceptet och skapa en gemensam referensram för alla deltagare gjordes funktionella 3D prototyper av  kartpussel föreställande Kreta. Prototyperna gjordes i trä, antingen tall eller MDF. Därefter organiserades fokusgrupper och intervjuer. I fokusgrupperna deltog vuxna och barn med synnedsättning. Aktiviteterna var scenariokreation, utvärdering av användarvänlighet och en enkätundersökning som fylldes in av de som kunde (personer med tillräckligt god syn). 

    Data som samlades analyserades med hjälp av kvalitativa och kvantitativa metoder. Resultatet av testerna visade potentiella användarvänlighetsproblem för prototyperna, de flesta relaterade till synskadade individers erfarenheter av linkande produkter. Dessutom identifierades deltagarnas preferenser och behov angående temat, storlek, material, typ av samband och andra faktorer av pusslet.  Resultaten visar att osäkerhet eller brist på bekräftelse huruvida pusselbitarna var lagda rätt eller fel var den största svårigheten bland deltagare med synnedsättning. Den mest populära metoden för låsning av pusselbitarna bland de med synnedsättning var ”fit in a frame” och ”magnets”. Majoriteten av deltagarna uppmuntrade att lägga till färger på pusslet och markera olika städer. Sex av åtta deltagare var intresserade av att köpa pussel liknande det som de testat. Av 22 icke synskadade personer svarade nio av dem att det är möjligt att de skulle köpa pusslet och elva svarade att det är väldigt möjligt att de skulle köpa tredimensionella pussel. Mer än hälften såg färger som ett tilläggselement på pusslet. De två mest populära låsningsmetoderna var ”loose contact” och ”fit in a frame”. Angående materialvalet, togs trä emot väl av både synskadade och icke-synskadade testpersoner. Träprototyper  var dock det enda tillgängliga under testet.

    Deltagare gav flera förslag angående temat, storlek och extra egenskaper för produkten. Det resulterade i att många idéer genererades under ”workshopen”. Utfall, problem och begränsningar relaterade till de använda metoderna diskuterades och rekommendationer för framtida studier gjordes.

    Fulltekst (pdf)
    fulltext
  • 479.
    ALEXANDRAKIS, VASSILIS
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    A participatory approach to the development of specifications for a 3D puzzle for visually impaired and sighted users2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Det finns begränsad tillgång till pussel för personer med synfel (inklusive blinda personer). För att undersöka behovet av potentiella användare i 3D kartpussel och identifiera deras preferenser, behov och krav, användes en kvalitativ metod som på engelska kallas ”participatory design”. Projektet utfördes i Kreta och alla deltagare kom från ön. Då Icke-standardiserade subjekt användes i forskningsprojektet användes lämpliga tillgängliga metoder och kommunikationsvägar för att anpassa studien för denna grupp. Stor vikt lades ner på bakgrundsstudier, inklusive intervjuer med experter och undersökning av befintligt material inom detta ämne.  För att underlätta förståelsen av konceptet och skapa en gemensam referensram för alla deltagare gjordes funktionella 3D prototyper av  kartpussel föreställande Kreta. Prototyperna gjordes i trä, antingen tall eller MDF. Därefter organiserades fokusgrupper och intervjuer. I fokusgrupperna deltog vuxna och barn med synnedsättning. Aktiviteterna var scenariokreation, utvärdering av användarvänlighet och en enkätundersökning som fylldes in av de som kunde (personer med tillräckligt god syn).  Data som samlades analyserades med hjälp av kvalitativa och kvantitativa metoder. Resultatet av testerna visade potentiella användarvänlighetsproblem för prototyperna, de flesta relaterade till synskadade individers erfarenheter av linkande produkter. Dessutom identifierades deltagarnas preferenser och behov angående temat, storlek, material, typ av samband och andra faktorer av pusslet.  Resultaten visar att osäkerhet eller brist på bekräftelse huruvida pusselbitarna var lagda rätt eller fel var den största svårigheten bland deltagare med synnedsättning. Den mest populära metoden för låsning av pusselbitarna bland de med synnedsättning var ”fit in a frame” och ”magnets”. Majoriteten av deltagarna uppmuntrade att lägga till färger på pusslet och markera olika städer. Sex av åtta deltagare var intresserade av att köpa pussel liknande det som de testat. Av 22 icke synskadade personer svarade nio av dem att det är möjligt att de skulle köpa pusslet och elva svarade att det är väldigt möjligt att de skulle köpa tredimensionella pussel. Mer än hälften såg färger som ett tilläggselement på pusslet. De två mest populära låsningsmetoderna var ”loose contact” och ”fit in a frame”. Angående materialvalet, togs trä emot väl av både synskadade och icke-synskadade testpersoner. Träprototyper  var dock det enda tillgängliga under testet.

    Deltagare gav flera förslag angående temat, storlek och extra egenskaper för produkten. Det resulterade i att många idéer genererades under ”workshopen”. Utfall, problem och begränsningar relaterade till de använda metoderna diskuterades och rekommendationer för framtida studier gjordes.

    Fulltekst (pdf)
    fulltext
  • 480.
    Alf Svensson, Joel
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energi och klimatstudier, ECS.
    Knowledge base and perception on sustainability in the long-haul transport sector in Brazil2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    demand for truck transportation is increasing and in the shadow the CO2 (carbon dioxide) emissions. In many parts of the world the majority of the transportation of goods is done by long-haulage trucks. More than 60% of all goods transported in Brazil are made by trucks (André Luiz Cunhaa, 2011). Therefore, it is critical to find solutions and actions on how to reduce the CO2 footprint.This thesis presents an evaluation of the knowledge and perceptions of sustainability among truck drivers and long-haulage freight transport companies in Brazil. For this, surveys to drivers and with a combination of surveys and interviews to logistics companies were done. The surveys and interviews covered energy and environmental related questions such as eco-driving, alternative fuels, fuel reductions actions, emissions, engine efficiency and the EU emissions standards.It has been found that only slightly more than half of the truck drivers have education in eco-driving despite that eco-driving is considered as the strongest action for reducing fuel consumption. In addition, many drivers do not know the benefits with eco-driving. However, this lack of knowledge among the drivers is in contrast known by the logistic companies. All logistics companies stated that eco-driving can decrease the fuel consumption by 10%, based on experience. The results are also an indication that there is a connection between companies with profit and eco-driving education. For companies with profit, 70% of the truck drivers have been educated in eco-driving, whereas companies with economic loss only 50% of the truck drivers are educated eco-driving . Another finding is that around half of the driver does not know the difference between the European emissions standards, again in contrast to the logistic companies management were all contacted knew the difference, i.e. emissions. This potentially indicates a lack of knowledge exchange between the management in logistic companies and the truck drivers.In addition to eco-driving, the drivers and logistics companies consider driving outside peak hours and the use of connectivity as strong actions for reducing their fuel consumption. Increasing the load capacity and custom made truck was not a frequent answer when asking how the drivers think they can reduce their fuel consumption. A result is also that one third of the logistic companies have been considering switching from petroleum diesel to alternative fuels.Both the truck drivers and the logistic companies know that the currently used trucks are not a sustainable transportation mode. They see the lack of economic incentives as the highest barrier for a more environment friendly transportation system and not the technology needed.In order to reduce the greenhouse gas emissions from the long-haulage sector, more drivers must be educated in eco-driving and the knowledge has to be increased regarding among other the benefits with eco-driving and the difference between the Euro standards. Decreasing the amount of empty trips is also an approach that should receive more attention.

    Fulltekst (pdf)
    fulltext
  • 481.
    Alfasfos, Rami
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Cavern Thermal Energy Storage for District Cooling. Feasibility Study on Mixing Mechanism in Cold Thermal Energy Storage2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Fulltekst (pdf)
    fulltext
  • 482. Alfredsson, Ludvig
    et al.
    Fazl, Asade
    Lund, Katarina
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Integrerad produktutveckling.
    Söderberg, Björn
    Product Development Management2011Inngår i: Entering the tigers cave – Perspectives on Japanese and Swedish Product Development / [ed] Bergsjö, Dag, Göteborg: Department of Product and Production Development, Chalmers University of Technology , 2011Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 483.
    Alfredsson, Simon
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Tengdelius, Fredrik
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Plasmaskärning: Metod, användning & utvecklingsmöjligheter2010Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Plasmaskärning är en form utav skärande bearbetning i metall med hjälp av en plasmastråle som smälter ett skärsnitt i arbetsstycket. Plasmastrålen bildas genom att en elektrisk båge mellan elektroden i verktyget och arbetsstycket värmer upp en skärgas till ett plasmatillstånd. På grund av den elektriska urladdningen mellan elektroden och arbetsstycket så måste materialet som bearbetas vara elektriskt ledande. Denna rapport ämnar grundligt redogöra plasmaskärning som skärmetod. Plasmaskärning är en av tre termiska skärningsmetoder (det finns även laser- och gasskärning). Rapporten behandlar kortfattat uppkomsten och den historiska utvecklingen för metoden. Därefter utreds grundligt skärprocessen samt de olika nyckelkomponenternas roll och tekniska funktion. De nyckelkomponenter som vi identifierade är; skär- och skyddsgas, elektrod, munstycke samt kringutrustning. Vidare diskuteras vilka risker och säkerhetsproblem som är förknippade med plasmaskärning. Ekonomiska aspekter och begränsningar påverkar metodens användningsområde. För att utreda när plasmaskärningsmetoden är bäst lämpad har vi därför valt att göra en jämförelse med andra termiska skärmetoder. Plasmaskärning har ett brett användningsområde men lämpar sig bäst på arbetsstycken mellan tjocklekarna 10 och 20 mm. En kortare marknadsundersökning genomfördes och presenteras i arbetet med syftet att klargöra på vilka grunder industrin valt typ av skärmetod samt hur de använder sig av den idag. Med hjälp av marknadsundersökningen jämför vi om det teoretiska användningsområdet stämmer överens med det praktiska ute på svenska industrier. Genom vår marknadsundersökning anser vi att många företag skulle kunna byta metod och därmed förbättra sin produktion främst med avseende på ekonomin. Slutligen framförs våra tankar kring potentiella utvecklingsmöjligheter för metoden som skulle kunna utöka dess konkurrenskraft jämfört med andra skärmetoder. Dessa diskuteras endast översiktligt och är tänkta som uppslag för vidare forskning inom området. Exempel på några av de utvecklingsmöjligheter som vi identifierat är; bearbetning av icke-ledande material med hjälp av en icke överförd ljusbåge, öka energitätheten i plasmastrålen genom att minimera munstyckets håldiameter, minimera risken för dubbelbåge genom bättre isolering av komponenterna i munstycket.

    Fulltekst (pdf)
    fulltext
  • 484.
    Algarp, Caroline
    et al.
    KTH, Skolan för industriell teknik och management (ITM).
    Svanfeldt, Astrid
    KTH, Skolan för industriell teknik och management (ITM).
    Optimal configuration for a bio-solar-wind polygeneration system in Klintehamn2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This project concentrates on the energy flows of Klintehamn and examines if it is possible for Klintehamn to be self-sufficient in the future. To reach this goal, the energy flows in Klintehamn must be analyzed. Subsequently, a new improved energy flow has been designed, where other renewable energy sources are included.

    Klintehamn is an urban area on the Swedish island of Gotland. An industrial park is established in the harbour of Klintehamn, and currently a sawmill, a fodder production facility and a few wind turbines are located in the area. A program, Program Klintehamn 2030, outlines opportunities to develop Klintehamn in many areas. The goals for Klintehamn are to increase the use of renewable energy sources and decrease greenhouse gas emissions. More specifically, this includes building a biogas plant by evolving the already established sewage treatment plant, and increasing the use of renewable energy sources such as wind and solar energy.

    Models of the Current Energy System and the Improved Energy System have been designed during the project. Calculations of the Current Energy System have been made and for the Improved Energy System, seven scenarios have been constructed. The calculations program, Matlab, has been used for all calculations. The following scenarios have been modeled in this project:

    • Scenario 1 - Development of biogas

    • Scenario 2 - Increased wind power

    • Scenario 3 - Development of solar park

    • Scenario 4 - Development of solar panels

    • Scenario 5 - Combination 1, scenario 1-4 added into one system

    • Scenario 6 - Combination 2, 100% renewable energy

    • Scenario 7 - Combination 3, development of Scenario 5, with more renewable energy

    In the Current Energy System, the total yearly energy demand is 3.423 TWh, where 3.405 TWh is electricity and 18.2 GWh is heat. The future demand of electricity and heat will be 3.407 TWh and 265 GWh per year, respectively. Scenario 5 is the first combined scenario, where the current energy and all renewable energy sources are included. The generated electricity in that scenario is not enough to satisfy the electricity demand. Scenario 6 consists of 100% renewable energy sources. To achieve the energy demand of Klintehamn all the renewable energy sources have been maximized in order to become self-sufficient. It generated an absurd result, which was far from realistic. Scenario 7 is an expansion of Scenario 5 but with more renewable energy. All energy sources have been expanded and Scenario 7 generates 108 GWh of electricity. Scenario 5 and Scenario 7 are two reasonable scenarios with reasonable amounts of renewable energy installed, but with different levels of ambition.

    The conclusion of the project is that, it is possible to improve the current energy system. The energy system can become more sustainable and fossil energy sources can be removed and replaced by renewable energy sources. In order for Klintehamn to be self-sufficient, more energy sources must be included, for example wave power.

    Fulltekst (pdf)
    fulltext
  • 485. Alghamdi, F.
    et al.
    Pears, Arnold Neville
    KTH, Skolan för industriell teknik och management (ITM), Lärande.
    Nylén, A.
    Computer science teachers perspectives on competencies - A case study in the Kingdom of Saudi Arabia2018Inngår i: 11th International Conference on Informatics in Schools: Situation, Evolution and Perspectives, ISSEP 2018, Saint-Petersburg, Russia, Springer, 2018, Vol. 11169, s. 129-140Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Kingdom of Saudi Arabia (KSA) has recently adopted the Saudi Teaching Competencies Standard (STCS). This paper tries to answer how these competencies are achieved, how they are maintained, and what support exists to support teaching CS competently in the KSA. This paper presents the results of an investigation of teacher awareness of, and attitudes to, the STCS in the Kingdom. Through the study reported here, we address an urgent need in the Kingdom to understand teacher preparedness in terms of CS teaching competencies. The study draws on interviews with ten CS teachers in five different cities in the KSA. A thematic coding analysis approach was used. This study explores the CS teaching competencies held by teachers in three areas of CS teaching, focusing on connection to society, professional practice and professional development. The results of the study highlight the CS teaching competencies that CS teachers feel they currently grasp well in the KSA. By enhancing awareness of what teachers currently do well we contribute to the adjustment and improvement of the STCS and help to build a program which addresses the current in-service training needs of CS teachers. The outcomes also help to raise awareness of the challenges of implementing the Computer Education curriculum in KSA schools.

  • 486.
    Al-Ghorabi, Marianne
    KTH, Skolan för industriell teknik och management (ITM), Lärande.
    Enhancing the degradation rate of microplastics and organizing a study visit about sustainability2020Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Microplastics take hundreds to thousands of years to degrade in nature, and pose a threat to the environment. A photocatalytical degradation method have been developed to take advantage of solar light to degrade microplastics, however it takes several months to degrade microplastics with the process. The purpose of this study is to enhance the degradation rate of microplastics by synthesizing a material where photocatalysis is combined with Fenton reaction. A material with zinc oxide nanorods coated with tin oxide and decorated with iron particles (𝑍𝑛𝑂/𝑆𝑛𝑂2/𝐹𝑒0) was synthesized and used to degrade methylene blue, polystyrene and polypropylene. The result show that the degradation rate with a 𝑍𝑛𝑂/𝑆𝑛𝑂2/𝐹𝑒0 – sample is faster than with a 𝑍𝑛𝑂 – sample, and that it can be used to degrade polystyrene and polypropylene.Students’ view on researchers can affect the development of their interest and attitude towards science. Study visits to laboratories have been used to increase students’ interest and give them new experiences. The purpose of this study is to investigate what and how high school students learn during a study visit to a nanotechnology laboratory, and how the study visit affects high school students’ interest and motivation for research and learning. A study visit with 5 stations was organized, and students were given a questionnaire about what they learned during the study visit. Thematic analysis was used to analyze the students’ answers. The result shows that the study visit increased students’ interest in research, and the importance of designing stations so that they are connected to students’ previous knowledge and are within their proximal development zone.

    Fulltekst (pdf)
    fulltext
  • 487.
    Algotsson, Martin
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Förlustsänkning i drivlina: En simuleringsmodell av hjulaxel till anläggningsmaskiner2008Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Med ökad fokus på miljöpåverkan och bränsleekonomi vill Volvo Construction Equipment öka verkningsgraden på sina anläggningsmaskiner. På avdelningen för drivlineutveckling jobbar man bland annat med att sänka förlusterna i växellåda och hjulaxel på hjullastare och dumper. För att underlätta detta arbete har en simuleringsmodell som beskriver förluster i hjulaxlar tagits fram. Denna rapport beskriver framtagning av modellen, verifiering av modellen och vilka framtida användningsområden modellen lämpar sig för.

    Simuleringsmodellen är uppbyggd av ett antal komponentmodeller. Komponentmodellerna innehåller formler för respektive komponent i hjulaxeln. Formlerna är tagna från ingenjörshandböcker, vetenskapliga artiklar och internt arbete på Volvo Construction Equipment. Bromsar, kuggväxlar, lager och tätningar är de komponenter i hjulaxeln som har studerats. De variabler som används i simuleringsmodellen är oljans viskositet, oljenivå i broms och centrum- och planetväxel, diameter och bredd på kugghjul och bromslamell, ingående varvtal och moment från kardanaxel, förspänningsmoment i lager samt maskinvikt. Matlab/Simulink är de program som har använts för att bygga modellen.

    Verifiering av simuleringsmodellen har gjorts genom att jämföra simuleringsresultat mot provningsresultat från tidigare gjorda riggkörningar på Volvo Construction Equipment. Då majoriteten av provningsresultaten kommer från riggkörningar utan bromsande moment är det endast de momentoberoende förlusterna som kunnat verifieras. Framtida riggkörningar med varierad hastighet och bromsande moment rekommenderas för att förstå och kunna verifiera de momentberoende förlusterna.

    Omplacering av bromsar till hjulnaven och en plåtkonstruktion vid centrumväxeln som sänker oljenivån är två förslag som kan ge en förlustsänkning i hjulaxeln. Med hjälp av simuleringsmodellen kan man uppskatta hur stor förlustsänkningen blir för båda idéerna och därefter rangordna dem. På detta sätt kan modellen vara ett värdefullt verktyg för att välja ut förslag som ska gå vidare i projekt.

    Då detta är en offentlig rapport är inga känsliga data eller referenser till interna publikationer på Volvo CE presenterade. För att kunna visa grafer har skalor och värden på axlar tagits bort.

    Fulltekst (pdf)
    Martin Algotsson
  • 488.
    Alhassan, I. B.
    et al.
    Univ Leeds, Inst Transport Studies, Leeds LS2 9JT, W Yorkshire, England..
    Matthews, B.
    Univ Leeds, Inst Transport Studies, Leeds LS2 9JT, W Yorkshire, England..
    Toner, J. P.
    Univ Leeds, Inst Transport Studies, Leeds LS2 9JT, W Yorkshire, England..
    Susilo, Yusak
    KTH, Skolan för industriell teknik och management (ITM), Centra, Integrated Transport Research Lab, ITRL. Univ Nat Resources & Life Sci, Inst Transport Studies, Peter Jordan St 82, A-1190 Vienna, Austria.
    Revisiting public transport service delivery: exploring rail commuters' attitudes towards fare collection and verification2019Inngår i: European Journal of Transport and Infrastructure Research, ISSN 1567-7133, E-ISSN 1567-7141, Vol. 19, nr 4, s. 310-331Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Making Public Transport services more attractive and effective requires attractive and effective ticketing. This requires a clear understanding of user attitudes, needs and expectations. This study explored commuters' attitudes to fare collection and verification and the underlying factors, their acceptance of the policy of "No-ticket-purchase on-board" and their preferences for fare verification options. Commuters rated their agreement with 17 ticketing related statements in a cross-sectional questionnaire survey conducted along the corridor with the largest proportion of cross-county commuting in Sweden, Stockholm - Uppsala. Four sets of hypotheses were then tested. The average scores were normally distributed and hence analysed using a two-way ANOVA. A One-way chi-square test was conducted to determine the commuters' preference for fare verification approach. A t-test was used to analyse the perceived quality of ticketing and the commuters' reaction to the policy of "No-ticket-purchase on-board PT vehicle". Whilst the results showed that the commuters were relatively uniform in their attitudes, income, commuting route, ticket type and ticket purchase channel affected their attitudes. They were neutral to the policy of "No-ticket-purchase on-board". Their attitude to fare collection was more positive than that of fare verification and they showed a preference for automatic fare verification. The study highlights a number of policy implications and recommends further research on the feasibility of passive fare verification and on commuters' preferred options for fare verification.

  • 489.
    Alhassan, Ilyas B.
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Tillämpad maskinteknik (KTH Södertälje).
    Mehmood, Tahir
    INTEGRATED MODEL FOR PROJECT RISK & UNCERTAINTY MANAGEMENT2012Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Fulltekst (pdf)
    fulltext
  • 490.
    Alhelfi, Ibrahim
    KTH, Skolan för industriell teknik och management (ITM), Hållbar produktionsutveckling (ML).
    Standardisering av pillerdosa med alarm2020Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Behandling med medicin innebär att inta rätt medicinsk mängd vid rätt tidpunkt. Mer en 50 % av patienterna missar minst en gång per vecka att inta sina mediciner enligt vårdrekommendationen.

    Victrix AB ville skapa en pillerdosa apparat som är anpassad för patienter med olika sjukdomar och svårigheter. Syftet är att underlätta användningen för patienter och gör det enklare att inta sina mediciner vid rätta tidpunkter med hjälp av en klocka som är kopplat till dosan. För att pillerdosan skulle nå största kundgruppen så måste den anpassas till olika patientbehov. Detta lede till att företaget ville skapa två olika modeller av dosan som kan kopplas till samma klockenhet. Den första modellen ska vara icke låsbar och ska levererastill ca. 90 % av patienterna. Den andra modellen ska vara låsbar och ska säljas till ca. 10 % av patienterna. Klockenheten skulle standardiseras för att anpassas till både modellerna.

    Arbetet är en vidare utveckling av ett tidigare examensarbete som har utförts av en grupp KTH-studenter i samarbete med Victrix AB år 2017.

    Fulltekst (pdf)
    fulltext
  • 491.
    Alhifi, Haidar
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Integrerad produktutveckling.
    Samir, Laith
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Integrerad produktutveckling.
    Design och konstruktion av släpvagnför tävlingsbilar2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    I samband med Transportstyrelsens införande av utökad B-körkortsbehörighet öppnades nya marknader för släpvagnar anpassade för transport av tävlingsbilar, verktyg och reservdelar. Sådana släpvagnar går att införskaffa sig idag på den svenska marknaden, dock är dessa endast anpassade för körkortsbehörigheten BE. Detta projekt utförs på uppdrag av företaget Fredrik Wagner AB, ett företag som designar och konstruerar transportband. Syftet med arbetet var att undersöka och utforska möjligheten för implementering av en ny släpvagnsmodell på den svenska marknaden. Målet med arbetet var att utveckla ett släpvagnskoncept anpassat för utökad B-behörighet, och därefter designa en CAD-modell av konceptet.Information om bilsporten och marknaden samlades in för att definiera och förstå problemet bättre. Därpå utfördes idé- och konceptgenereringsfaser för att hitta lösningar till problemet. Dessa lösningar utvecklades sedan till ett CAD-koncept med hjälp av CAD-programmet Solid Edge.Konstruktionsarbetet begränsades i detta projekt till släpvagnens påbyggnad och dess ingående komponenter. Påbyggnadskonceptet erbjuds i två utföranden, det ena är anpassat för utökad B-behörighet medan det andra är för BE-behörighet. För utökad B-behörighet blev påbyggnadens totala vikt 695 kg medan vikten för BE-behörighet blev 1 005 kg.Släpvagnen är konstruerad för att transportera tävlingsbilar med en vikt på 1 100 kg, det är dock även möjligt att transportera andra bilar med släpvagnen om dessa inte överstiger viktbegränsningen. Eftersom arbetet begränsades till endast påbyggnaden har konstruktionen av ett chassi uteslutits. Chassit kan antigen köpas från någon leverantör eller konstrueras av Fredrik Wagner AB. Hur chassit och påbyggnaden ska monteras ihop är något som utelämnades för vidare arbete.

    Fulltekst (pdf)
    Design and construction of a trailer for racing cars
  • 492.
    Alhusin Alkhdur, Abdullah
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Toward a Sustainable Human-Robot Collaborative Production Environment2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This PhD study aimed to address the sustainability issues of the robotic systems from the environmental and social aspects. During the research, three approaches were developed: the first one an online programming-free model-driven system that utilises web-based distributed human-robot collaboration architecture to perform distant assembly operations. It uses a robot-mounted camera to capture the silhouettes of the components from different angles. Then the system analyses those silhouettes and constructs the corresponding 3D models.Using the 3D models together with the model of a robotic assembly cell, the system guides a distant human operator to assemble the real components in the actual robotic cell. To satisfy the safety aspect of the human-robot collaboration, a second approach has been developed for effective online collision avoidance in an augmented environment, where virtual three-dimensional (3D) models of robots and real images of human operators from depth cameras are used for monitoring and collision detection. A prototype system is developed and linked to industrial robot controllers for adaptive robot control, without the need of programming by the operators. The result of collision detection reveals four safety strategies: the system can alert an operator, stop a robot, move away the robot, or modify the robot’s trajectory away from an approaching operator. These strategies can be activated based on the operator’s location with respect to the robot. The case study of the research further discusses the possibility of implementing the developed method in realistic applications, for example, collaboration between robots and humans in an assembly line.To tackle the energy aspect of the sustainability for the human-robot production environment, a third approach has been developed which aims to minimise the robot energy consumption during assembly. Given a trajectory and based on the inverse kinematics and dynamics of a robot, a set of attainable configurations for the robot can be determined, perused by calculating the suitable forces and torques on the joints and links of the robot. The energy consumption is then calculated for each configuration and based on the assigned trajectory. The ones with the lowest energy consumption are selected.

    Fulltekst (pdf)
    fulltext
  • 493. Ali, A.
    et al.
    Rafique, A.
    Kaleemullah, M.
    Abbas, G.
    Ajmal Khan, M.
    Ahmad, M. A.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. Chinese Academy of Sciences, China.
    Effect of Alkali Carbonates (Single, Binary, and Ternary) on Doped Ceria: A Composite Electrolyte for Low-Temperature Solid Oxide Fuel Cells2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 1, s. 806-818Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Samarium-doped ceria (SDC) carbonate has become an attractive electrolyte for fuel cells because of its remarkable ion conductivity and high performance. Different doped ceria-carbonate (single-carbonate SDC, binary-carbonate SDC, and ternary-carbonate SDC) electrolytes were synthesized by the coprecipitation/oxalate method, to optimize the electrochemical performance. The structure; morphology; and thermal, optical, and surface properties have been studied using a variety of techniques. The X-ray diffraction results confirmed the successful incorporation of samarium into ceria as a crystalline structure and inclusion of carbonate, which is amorphous in nature. To analyze the conduction mechanism, direct current conductivity was measured in a H2/O2 atmosphere. Doped ceria-binary carbonate ((Li/Na)CO3-SDC) showed the best conductivity of 0.31 S cm-1 and power density of 617 mW cm-2, at 600 °C. The enhancement in the ionic conductivity and performance of the composites is due to the contribution of hybrid ions (O2-, H+). The crystallite size of the composites was in the range 21-41 nm. For the calculation of band gaps, optical absorption spectra of the synthesized powders were analyzed, and they showed a red shift with the band gap energy in the range 2.6-3.01 eV, when compared to that of pure ceria (3.20 eV).

  • 494. Ali, A.
    et al.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Kaleem Ullah, M.
    Rafique, A.
    Wang, B.
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. Hubei University, China.
    Alkaline earth metal and samarium co-doped ceria as efficient electrolytes2018Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 112, nr 4, artikkel-id 043902Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Co-doped ceramic electrolytes M0.1Sm0.1Ce0.8O2-δ (M = Ba, Ca, Mg, and Sr) were synthesized via co-precipitation. The focus of this study was to highlight the effects of alkaline earth metals in doped ceria on the microstructure, densification, conductivity, and performance. The ionic conductivity comparisons of prepared electrolytes in the air atmosphere were studied. It has been observed that Ca0.1Sm0.1Ce0.8O2-δ shows the highest conductivity of 0.124 Scm-1 at 650 °C and a lower activation energy of 0.48 eV. The cell shows a maximum power density of 630 mW cm-2 at 650 °C using hydrogen fuel. The enhancement in conductivity and performance was due to increasing the oxygen vacancies in the ceria lattice with the increasing dopant concentration. The bandgap was calculated from UV-Vis data, which shows a red shift when compared with pure ceria. The average crystallite size is in the range of 37-49 nm. DFT was used to analyze the co-doping structure, and the calculated lattice parameter was compared with the experimental lattice parameter.

  • 495.
    Ali, Amjad
    et al.
    COMSATS Univ, Dept Phys, CERL, Lahore Campus, Lahore 54000, Pakistan.;Univ Okara, Dept Phys, Okara 56300, Pakistan.;KTH, Dept Mat Sci & Engn, SE-10044 Stockholm, Sweden..
    Bashir, Farrukh Shehzad
    COMSATS Univ, Dept Phys, CERL, Lahore Campus, Lahore 54000, Pakistan..
    Raza, Rizwan
    COMSATS Univ, Dept Phys, CERL, Lahore Campus, Lahore 54000, Pakistan.;Royal Inst Technol KTH, Dept Energy Technol, S-10044 Stockholm, Sweden..
    Rafique, Asia
    COMSATS Univ, Dept Phys, CERL, Lahore Campus, Lahore 54000, Pakistan..
    Ullah, Muhammad Kaleem
    COMSATS Univ, Dept Phys, CERL, Lahore Campus, Lahore 54000, Pakistan..
    Alvi, Farah
    COMSATS Univ, Dept Phys, CERL, Lahore Campus, Lahore 54000, Pakistan..
    Afzal, Muhammad
    Royal Inst Technol KTH, Dept Energy Technol, S-10044 Stockholm, Sweden..
    Ghauri, Moinuddin
    COMSATS Univ Islamabad, Dept Chem Engn, Lahore Campus, Lahore 54000, Pakistan..
    Belova, Lyubov M.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Electrochemical study of composite materials for coal-based direct carbon fuel cell2018Inngår i: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 43, nr 28, s. 12900-12908Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The efficient conversion of solid carbon fuels into energy by reducing the emission of harmful gases is important for clean environment. In this regards, direct carbon fuel cell (DCFC) is a system that converts solid carbon directly into electrical energy with high thermodynamic efficiency (100%), system efficiency of 80% and half emission of gases compared to conventional coal power plants. This can generate electricity from any carbonaceous fuel such as charcoal, carbon black, carbon fiber, graphite, lignite, bituminous coal and waste materials. In this paper, ternary carbonate-samarium doped ceria (LNK-SDC) electrolyte has been synthesized via co-precipitation technique, while LiNi-CuZnFeO (LNCZFO) electrode has been prepared using solid state reaction method. Due to significant ionic conductivity of electrolyte LNK-SDC, it is used in DCFC. Three types of solid carbon (lignite, bituminous, sub-bituminous) are used as fuel to generate power. The X-ray diffraction confirmed the cubic crystalline structure of samarium doped ceria, whereas XRD pattern of LNCZFO showed its composite structure. The proximate and ultimate coal analysis showed that fuel (carbon) with higher carbon content and lower ash content was promising fuel for DCFC. The measured ionic conductivity of LNK-SDC is 0.0998 Scm(-1) and electronic conductivity of LNCZFO is 10.1 Scm(-1) at 700 degrees C, respectively. A maximum power density of 58 mWcm(-2) is obtained using sub bituminous fuel.

  • 496.
    Ali, Amjad
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. COMSATS Inst Informat Technol, Dept Phys, Lahore 54000, Pakistan.;Univ Okara, Dept Phys, Okara 56300, Pakistan.
    Raza, Rizwan
    COMSATS Inst Informat Technol, Dept Phys, Lahore 54000, Pakistan.;Royal Inst Technol KTH, Dept Energy Technol, S-10044 Stockholm, Sweden..
    Khalil, R. M. Arif
    Bahauddin Zakariya Univ, Dept Phys, Multan 60800, Pakistan..
    Ahmad, M. Ashfaq
    COMSATS Inst Informat Technol, Dept Phys, Lahore 54000, Pakistan..
    Rafique, Asia
    COMSATS Inst Informat Technol, Dept Phys, Lahore 54000, Pakistan..
    Ullah, M. Kaleem
    COMSATS Inst Informat Technol, Dept Phys, Lahore 54000, Pakistan..
    Rehman, Amin Ur
    Lahore Univ, Dept Phys, Lahore 54000, Pakistan..
    Mushtaq, M. Naveed
    COMSATS Inst Informat Technol, Dept Phys, Lahore 54000, Pakistan..
    Belova, Lyubov
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    A potential electrolyte (Ce1-x CaxO2-delta) for fuel cells:Theoretical andexperimental study2018Inngår i: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 44, nr 11, s. 12676-12683Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    First-principles calculations are performed using density function theory to explore the effects of dopant Ca in ceria (Ce1-x CaxO2-delta). The impact of oxygen vacancy on band gap and density of states is examined in doped ceria using generalized gradient approximations. Vacancy association and vacancy formation energies of the doped ceria are calculated to reveal the effect of dopant on ion conduction. The experimental study of the sample Ce0.875Ca0.125O2-delta) was performed to compare with the theoretical results. The obtained results from theoretical calculation and experimental techniques show that oxygen vacancy increases the volume, lattice constant (5.47315 angstrom) but decrease the band gap (1.72 eV) and bulk modulus. The dopant radius (1.173 angstrom) and lattice constant (5.4718 angstrom) are also calculated by equations which is close to the DFT lattice parameter. The result shows that oxygen vacancy shifts the density of states to lower energy region. Band gap is decreased due to shifting of valence states to conduction band. Vacancy formation shows a significance increase in density of states near the Fermi level. Density of states at Fermi level is proportional to the conductivity, so an increase in density of states near the Fermi level increases the conductivity. The experimental measured ionic conductivity is found to 0.095 S cm(-1) at 600 degrees C. The microstructural studies is also reported in this work.

  • 497.
    Ali, Faiza
    et al.
    KTH, Skolan för industriell teknik och management (ITM).
    Schröder, Martin
    KTH, Skolan för industriell teknik och management (ITM).
    W.A.N.T: Weightlifting Ant2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The purpose of this project is to create a light weight robotic version of an ant that can withstand great forces, trying to come close to the ant’s lifting technique as much as possible. This idea was chosen with inspiration from nature, especially from the obscure forces of an ant. These insects are proven to be able to lift and carry heavy loads, up to a thousand times their body weight. Various lifting technologies are used by several facilities today and therefore there is a need for improvements in this field.

    By trying to come close to an ant’s appearance and mimic certain ant movements, a hexapod was designed over a period of four months. The tests made in this project were divided into three categories; stability, lifting and gripping ability. The best balance was achieved by placing the legs’ contact points on the ground as far away from each other as possible. In total the robot ant could lift about 1.02 times its own weight and bear 3.01 times its own weight on the thorax.

    Fulltekst (pdf)
    fulltext
  • 498.
    Ali Kazmi, Syed
    KTH, Skolan för industriell teknik och management (ITM), Tillämpad maskinteknik (KTH Södertälje).
    Impact of Natural, Man-made Risks and Stakeholders Relationship on effectiveness of Supply Chain Management in Developing Countries2017Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Fulltekst (pdf)
    fulltext
  • 499.
    Ali, Naik Bakhat
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Tillämpad maskinteknik (KTH Södertälje).
    Abdulzahra, Abbas
    KTH, Skolan för industriell teknik och management (ITM), Tillämpad maskinteknik (KTH Södertälje).
    Framtagande av system för strukturerat förbättringsarbete i verkstadsmiljö2018Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Syftet med projektet var att studera ständiga förbättringar och observera förbättringsarbete i praktiken på en av Sandvik SRP avdelningar som kallas för West samt komma konkreta förslag för hur detta kan förbättras. Med andra ord att analysera sättet WEST jobbar på i dagsläget och skapa ett system för ständiga förbättringar i en verkstadsmiljö, som effektiviserar arbetet med ständiga förbättringar. Sandvik har byggt denna avdelning nyligen, och där jobbar man med finbearbetning av olika detaljer.

    Examensarbetet påbörjades med en litteraturstudie om ständiga förbättringar såsom bakgrunden, implementeringen med hjälp av Bessants fem nivåer samt nyckelfaktorer. Författarna valde att nämna de två viktigaste metoderna, PDCA och 5s. Detta gjordes eftersom verktygen används flitigt på företaget och för att få ett bättre förståelse.

    Efter detta genomfördes observation samt flera intervjuer. Observationen bestod av personalmöten, undersökningar av olika maskiner och processer som används på West, såsom finbearbetning, svetsning mm. Dessutom flera andra system som används för att arbeta med ständiga förbättringar och behålla en bra arbetsmiljö ̈. Intervjuer som utfördes var med Produktionsteknik Chefen Magnus, Operationell Excellens Lars Melbrand och produktionsledare Verdana från en annan avdelningen som har en viktig roll i arbetet med ständiga förbättringar samt flera maskinoperatörer/Teamledare.

    Nulägesanalysen gjordes genom att rita ett morellträd för att försöka skapa en så tydlig bild som möjligt av den nuvarande situationen inom olika områden för att på sikt kunna hitta orsaken till problemen som uppstår och som hindrar företaget från att förbättras ständigt. Dessutom analyserades de arbetsmetoderna som används idag samt vilka missuppfattningarna som finns bland medarbetarna som tillexempel för PDCA. Det finns inget riktigt system för utbildningen av personal på företaget, så att de kan lära sig de nya systemen och metoder som implementeras. Kommunikationen mellan maskinoperatörer och produktionstekniker är låg samt att det inte finns några mål kopplade till individ eller grupp för ständiga förbättringar.

    Efter att ha analyserat nuvarande situationen av avdelningen och konstaterat att WEST ligger mellan nivå 2 och 3 på Bessants fem nivåer (2003), har författarna presenterat ett antal förbättringsförslag inom olika områden som behöver förbättras. Detta gjordes med hjälp av en jämförelse med Kaye & Andersons nyckelfaktorer som är tio checkpunkter för att få en tydlig bild av organisationens nuvarande position och kapacitet.

    Resultat av analysen illustreras av ett modellträd. I det nya trädet har områdena analyserats och förbättrats.

    Fulltekst (pdf)
    fulltext
  • 500.
    ALI, OMAR
    KTH, Skolan för industriell teknik och management (ITM).
    Evaluating Board Work for Innovation.: Towards an Analytical Framework.2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    There is an increased need for innovation activities in companies today due to mounting pressure from external factors increasing the urgency for renewal and agility. Digitalisation of processes, products and services sets completely new requirements for competence but also changes the value creation and competitiveness. In recent years, management focus has shifted from optimization of production processes, logistics and supply chains, to being more oriented towards an innovation focus, promoting business renewal and innovative business models.

    The purpose of this study is to examine how board evaluations are used to improve board work and to study how well boards guide the innovation ambitions of their companies. Furthermore, the aim of this study is to develop a framework that can provide a holistic perspective of both control and strategic innovation aspects. Results from a comprehensive literature review and analysis of board evaluation data indicate that there is a lack of innovation inclusion in board evaluations and a clear lack of statistical approach when constructing surveys.

    The result of the study is a proposed framework that provides guidance for designing an innovation inclusive board evaluation tools and recommendations for providing actionable insights to clients, backed up by statistical models such as regression analysis and consistency analysis that has the possibility to scale into a digital assessment tool.

    Fulltekst (pdf)
    fulltext
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