Ändra sökning
Avgränsa sökresultatet
1234567 1 - 50 av 16948
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    A Asif, Farazee M
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Maskin- och processteknologi.
    Circular Manufacturing Systems: A development framework with analysis methods and tools for implementation2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The society today lives on the philosophy of ‘take-make-use-dispose.’ In the long run, this is not sustainable as the natural resources and the waste carrying capacity of the earth are limited. Therefore, it is essential to reduce dependency on the natural resources by decoupling the growth from the consumption. In this venture, both the society and the manufacturing industry have a vital role to play. The society needs to shift towards Circular Economy that rests upon the philosophy of ‘take-make-use-reuse’ and the manufacturing industry has to be a major stakeholder in this shift. Despite being proven to be both economically and environmentally beneficial, successful examples of circular systems are few today. This is primarily due to two reasons; firstly, there is a lack of systemic and systematic approach to guide industries and secondly, there is a lack of analysis methods and tools that are capable of assessing different aspects of circular manufacturing systems. Taking on to these challenges, the objective of this research is to bring forward a framework with methods and decision support tools that are essential to implement circular manufacturing systems. The initial conceptual framework with the systemic approach is developed based on extensive review and analysis of research, which is further adapted for industrial implementation. Systematic analysis methods, decision support and implementation tools are developed to facilitate this adaptation. This development has been supported by four cases from diverse manufacturing sectors. Behind each decision support tool, there are analysis methods built upon mainly system dynamics principles. These tools are based on simulation platforms called Stella and Anylogic. Among other things, these tools are capable of assessing the performance of closed-loop supply chains, consequences of resource scarcity, potential gains from resource conservation and overall economic and environmental performance of circular manufacturing systems.

  • 2.
    A Asif, Farazee M
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Maskin- och processteknologi.
    Rashid, Amir
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Maskin- och processteknologi.
    Bianchi, Carmine
    University of Palermo (ITALY) Faculty of Political Sciences - Department of International Studies .
    Nicolescu, Mihai
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Maskin- och processteknologi.
    Performance analysis of the closed loop supply chain2012Ingår i: Journal of Remanufacturing, ISSN 2210-4690, Vol. 2, nr 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose

    The question of resource scarcity and emerging pressure of environmental legislations has brought a new challenge for the manufacturing industry. On the one hand, there is a huge population that demands a large quantity of commodities; on the other hand, these demands have to be met by minimum resources and pollution. Resource conservative manufacturing (ResCoM) is a proposed holistic concept to manage these challenges. The successful implementation of this concept requires cross functional collaboration among relevant fields, and among them, closed loop supply chain is an essential domain. The paper aims to highlight some misconceptions concerning the closed loop supply chain, to discuss different challenges, and in addition, to show how the proposed concept deals with those challenges through analysis of key performance indicators (KPI).

    Methods

    The work presented in this paper is mainly based on the literature review. The analysis of performance of the closed loop supply chain is done using system dynamics, and the Stella software has been used to do the simulation. Findings The results of the simulation depict that in ResCoM; the performance of the closed loop supply chain is much enhanced in terms of supply, demand, and other uncertainties involved. The results may particularly be interesting for industries involved in remanufacturing, researchers in the field of closed loop supply chain, and other relevant areas. Originality The paper presented a novel research concept called ResCoM which is supported by system dynamics models of the closed loop supply chain to demonstrate the behavior of KPI in the closed loop supply chain.

  • 3.
    A Monfared, Behzad
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Design and Construction of a Small Ammonia Heat Pump2010Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In view of the fact that most of the synthetic refrigerants, in case of leakage or release, are harmful to the environment by contributing in global warming or depleting stratospheric ozone layer, many research works have been done recently to find alternative refrigerants posing no or negligible threat to the environment. Among alternative refrigerants, ammonia, a natural refrigerant with zero Global Warming Potential (GWP) and Ozone Depletion Potential (ODP), can be a sensible choice.Although ammonia has been used for many years in large industrial systems, its application in small units is rare. In this project a small heat pump with about 7 kW heating capacity at -5 °C and +40 °C evaporation and condensation temperatures is designed and built to work with ammonia as refrigerant. The heat pump is expected to produce enough heat to keep a single-family house warm in Sweden and to provide tap hot water for the house. After successful completion of this project, it is planned to install the heat pump in a house to test it throughout a heating season to study its performance in real working conditions.Since ammonia is flammable and toxic in high concentrations, the refrigerant charge is tried to be kept low in the heat pump to reduce the risk of fire or poisoning in case of unwanted release of refrigerant to the surroundings. The compact design of the heat pump helps reducing the refrigerant charge. Besides, considering the limited space normally reserved for installation of a heat pump in a house, the compact design of the heat pump is necessary.

  • 4.
    A Monfared, Behzad
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Magnetic Refrigeration for Near Room-Temperature Applications2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Kylning spelar en avgörande roll i många olika sektorer och förbrukar cirka 17 % av den elektricitet som produceras globalt. Kylprocessernas energiförbrukning utgör alltså en stor andel av primärenergiförbrukningen och innebär även annan miljöpåverkan. Förutom miljöpåverkan som är förknippad med energiförbrukningen bidrar ångkompressionssystemen till global uppvärmning på grund av utsläpp av köldmedier i atmosfären. Som en alternativ teknik för nära rumstemperaturapplikationer föreslås magnetisk kylning av vissa forskare, för att eliminera utsläpp av köldmedier i atmosfären och för att minska energiförbrukningen. Denna avhandling är en sammanställning av ett antal studier om magnetisk kylning för rumstemperaturapplikationer.

    I den första studien undersöktes de miljöpåverkningar som är förknippade med magnetisk kylning noggrant genom en livscykelanalys. Livscykelanalysen indikerar att minskningen av miljöpåverkan inte garanteras genom att byta till den magnetiska kylprocessen på grund av de miljöbelastningar som är relaterade till de sällsynta jordartsmetaller som används i magnetisk kylning. För att undvika de extra miljöpåverkningarna bör de magnetiska kylsystemen använda så lite magnetiska material som möjligt, vilket kräver en optimerad design. Dessutom är energieffektivare drift jämfört med ångkompressionssystemen nödvändigt för att få miljöfördelar, åtminstone i vissa miljöpåverkanskategorier.

    En praktisk metod för att optimera designen av magnetiska kylsystem, för att uppnå t.ex. en kompakt design eller hög effektivitet, är användning av en flexibel mjukvarumodell, som simulerar effekten av olika parametrar på systemets prestanda. En sådan mjukvarumodell av det magnetiska kylsystemet har utvecklats och validerats i detta projekt. Ett syfte med utvecklingen av modellen är att öka precisionen av de simulerade resultaten genom att ta hänsyn till mer detaljer än i tidigare modeller. Detta mål uppnås genom ett innovativt sätt att modellera den parasitära värmeöverföringen och inkludera effekten av närvaron av magnetokaloriska material på styrkan av fältet som skapas av magnetaggregatet. Dessutom görs vissa modifieringar eller korrigeringar i de befintliga korrelationerna för att inkludera effekten av bindemedel som används i vissa aktiva magnetiska regeneratorer. Validering av den utvecklade mjukvarumodellen görs med hjälp av experimentella resultat som erhållits från den prototyp som finns vid Institutionen för Energiteknik, Kungliga Tekniska Högskolan.

    En av parametrarna som kan modifieras i den utvecklade mjukvarumodellen är valet av magnetokaloriska material för varje skikt i en skiktad aktiv magnetisk regenerator. Användning av mjukvarumodellen för att optimera valet av material för skikten visar att material med kritiska temperaturer som är lika med den cykliska genomsnittstemperaturen hos de skikt där de används inte nödvändigtvis resulterar i önskad optimal prestanda. Dessutom behövs olika materialval för skikten för att maximera modellernas resultat avseende energieffektivitet eller temperaturskillnaden som erhålls mellan de två ändarna av regeneratorerna. Därför är valet av kritiska temperaturer för skiktens material en ytterligare parameter som ska optimeras i studier med avsikt att förbättra ett systems prestanda.

    Prototypen vid Institutionen för Energiteknik, Kungliga Tekniska Högskolan, var ursprungligen designad för att ersätta ångkompressionssystemet för ett restaurangkylskåp. Det kunde emellertid inte uppfylla de krav för vilka det ursprungligen utformats. Den ovan nämnda utvecklade simuleringsmodellen används för att undersöka hur mycket prestandan kan förbättras genom att förändra valet av material, partikelstorleken, antalet skikt, driftsfrekvensen och flödeshastigheten av värmeöverföringsvätskan. Med andra ord undersöks utrymmet för förbättring av prestandan utan att genomföra stora förändringar i systemet, såsom förändringar i regeneratorers geometri och i magnetaggregatet. Under processen undersöks effekten av bindemedel på prestanda och begränsningar som är förknippade med bindemedlets egenskaper. Trots detta kunde studien inte visa att de ursprungliga målen för prototypen kan uppnås utan att ändra regeneratorernas geometri och de befintliga magnetokaloriska materialen.

    I nästa studie övervägs mer flexibla val av regeneratorernas geometrier och magnetokaloriska material. I den här studien undersöks hur mycket de magnetokaloriska materialen måste förbättras för att magnetiska kylsystem ska kunna konkurrera med ångkompressionssystem vad gäller prestanda. För de två undersökta fallen är de magnetfältberoende egenskaperna hos befintliga materialen tillräckliga förutsatt att vissa andra problem, såsom låg mekanisk stabilitet och inhomogenitet hos egenskaperna, löses. Emellertid, för mer krävande designkriterier, såsom att ge stor kylkapacitet över en betydande temperaturdifferens samtidigt som de magnetiska materialen används sparsamt, behöver de magnetfältberoende egenskaperna också förbättras.

    Ett mindre undersökt område för magnetisk kylning i rumstemperatur är föremål för en annan studie som ingår i avhandlingen. I denna studie modelleras fasta magnetiska kylsystem med Peltier-element som värmebrytare. Eftersom Peltier-elementen förbrukar elektricitet och pumpar värmen kan de modellerade systemen betraktas som hybrid magnetokalorisk-Peltier-kylsystem. För sådana system modelleras i detalj det transienta beteendet hos Peltier-elementen tillsammans med de magnetokaloriska materialskikten. Den matematiska modellen är lämplig för implementering i programmeringsspråk utan behov av kommersiella modelleringsplattformar. Parametrarna som påverkar det modellerade systemets prestanda är många, och optimering av dem kräver en separat studie. De preliminära optimeringsinsatserna ger emellertid inte lovande resultat. Följaktligen kan fokusering på passiva värmebrytare vara mer fördelaktiga.

  • 5.
    A Österman, Sami
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Kumar, Shirish
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Vattenskärning: Teknologin och dess tillämpningsområden2010Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Vattenskärning anses generellt vara en mångsidig bearbetningsteknik med en mängd tillämpningsområden. Ren vattenskärning gör det möjligt att skära i mjuka material som gummi, medan tillsatt abrasivmedel tillåter skärning av bland annat stål och keramik. Skärningen lämnar inga restspänningar eller någon värmepåverkan i materialet. Dessutom blir ytfinheten så bra att man ofta slipper efterbehandling. Processen skapar inte heller några farliga gaser och är relativt miljövänlig. Syftet med detta arbete har varit att undersöka vattenskärningstekniken, dess nuvarande samt nya tillämpningsområden. Målet har även varit att jämföra tekniken med alternativa bearbetningsmetoder för att klargöra för‐ och nackdelar mellan dessa. Detta gjordes i syfte för att undersöka vilken teknik som är lämpligast att använda beroende på egenskaper såsom material, materialtjocklek och storlek av tillverkad serie. Arbetet har skrivits från Sverige och Frankrike och därmed har man valt att undersöka ifall användningsområdena hos vattenskärning skiljer sig mellan de två länderna. För att uppnå syftet valdes tre frågeställningar för att besvara hur man utökar tillämpningsområdet för vattenskärning, vilka för‐ respektive nackdelar vattenskärning har jämfört med andra skärmetoder och hur tillämpningsområdena är annorlunda mellan Frankrike och Sverige. De huvudsakliga informationskällorna för arbetet har varit intervjuer med tillverkande företag som använder sig av vattenskärning, leverantörer av vattenskärningsmaskiner och forskningsinstitut. Teoretisk komplettering har skett i form av informationssamling från litteratur och vetenskapliga artiklar. Valda primärkällor är företagshemsidor hos aktörer inom bearbetningsindustrin. Rapporten visar att vattenskärningstekniken är applicerbar inom ett flertal industrier och att tillämpningsområdena skiljer sig mellan Frankrike och Sverige; i Frankrike används vattenskärning främst inom livsmedelsindustrin, medan den är mer utbredd inom verkstadsindustrin i Sverige. Aktörer på den svenska marknaden är skeptiska till användning av vattentryck på över 400 MPa, trots att det tyder på många fördelar. Den huvudsakliga begränsningen hos vattenskärning är tjockleken hos materialet. Vid skärning av stål över 30 mm kan strålen fördröjas och resultera i en ickeprecis skärning, ett problem som löses genom att ändra skärparametrar såsom skärhastighet eller genom snedställning av skärmunstycket. Efter en utvärdering av plasma‐, laser‐ och vattenskärning, kan man konstatera att ingen metod är direkt konkurrerande med en annan, då varje teknik lämpar sig bäst inom sitt respektive användningsområde. Teknikerna kompletterar snarare än konkurrerar med varandra.

  • 6.
    Aaman, Sophia
    et al.
    KTH, Skolan för industriell teknik och management (ITM).
    Hessel Lundberg, Johan Henrik
    KTH, Skolan för industriell teknik och management (ITM).
    Setting the seeds for a green growth -A Study of biofuel development in Indonesia’s transport sector2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
  • 7. Aarrevaara, Timo
    et al.
    Pinheiro, Rómulo
    Söderlind, Johan
    KTH, Skolan för industriell teknik och management (ITM), Lärande.
    Strategy as Dialogue and Engagement2019Ingår i: Reforms, Organizational Change and Performance in Higher Education: A Comparative Account from the Nordic Countries / [ed] Rómulo Pinheiro, Lars Geschwind, Hanne Foss Hansen, Kirsi Pulkkinen, Cham: Palgrave Macmillan, 2019, s. 211-234Kapitel i bok, del av antologi (Refereegranskat)
  • 8.
    Abacar, Armando
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Optimization of Maputo Power Plant2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The Electricidade de Moçambique, E.P. (EDM) is the power utility in Mozambique, responsible to generate, transport and distribute electricity all over the country. The company has three gas turbines installed at Maputo Power Plant. All units burn diesel oil and are used only for back up. Currently only the unit #2 is available for operation.

    The main constraint that EDM faces is the high operation costs due to diesel price. Hence the company is considering converting units #2 and #3 to burn natural gas, resource available locally. The country is currently exporting natural gas to the neighbouring Republic of South Africa.

    This MSc thesis project calculates the power output of all gas turbines when burning natural gas and optimizes the power plant capacity by proposing modifications of the current power turbine cycles to allow sustainable operation

  • 9.
    Abakarova, Elmira
    et al.
    Gubkin University, Moscow.
    Blomgren, Henrik
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekonomi och organisation (Inst.), Industriell marknadsföring. KTH, Skolan för industriell teknik och management (ITM), Industriell ekonomi och organisation (Inst.), Affärsutveckling och Entreprenörskap.
    Will the future European energy market be a German battle with Russian and Swedish actors in the centre of it?: Analyzing major players with the pattern shown by mergers and acquisitions2011Konferensbidrag (Refereegranskat)
  • 10. Abas, R. Abdul
    et al.
    Seetharaman, Seshadri
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Thermal diffusivity of sintered stainless steel-alumina composites2006Ingår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 37, nr 4, s. 513-518Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thermal diffusivity measurements were carried out as a function of temperature on sintered AISI 304 stainless steel-alumina composites having various compositions (0.001, 0.01, 0, 1, 1, 2, 3, 5, 7, 8, and 10 wt pct Al2O3). The measurements were carried out between room temperature and 1473 K. The thermal diffusivity and the thermal conductivity were found to increase with temperature in all the composite specimens. The thermal diffusivity was found to decrease with increasing weight fraction of alumina. This tendency can clearly be seen at temperatures above 755 K. The experimental results are in good agreement with the simple rule of mixture, the Eucken equation, and the Ohm's law model developed by Hayashi et al. at weight fractions of alumina below 5 wt pct. Beyond this composition, the thermal diffusivity/conductivity shows a large discrepancy from the models. This could probably be attributed to the accumulation of alumina particles during cooled pressing and sintering.

  • 11.
    Abas, Riad Abdul
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Property measurements towards understanding process phenomena2005Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The main objective of this industrially important work was to gain an increasing understanding of the properties of materials such as CMSX-4 nickel base super alloy, mould powder used in continuous casting of steel and coke used in blast furnace, with special reference to the thermal diffusivities. The measurements were carried out in a wide temperature range, solid, liquid, glassy and crystalline states.

    For CMSX-4 alloy, the thermal conductivities were calculated from the experimental thermal diffusivities. Both the diffusivities and conductivities were found to increase with increasing temperature. Microscopic analysis showed the presence of intermetallic phases such as NiTi and NiTi2 below 1253 K. In this region, the mean free path of the phonons is likely to be limited by scattering against lattice defects. Between 1253 K and solidus temperature, these phases dissolved in the alloy adding to the impurities in the matrix, which, in turn, caused a decrease in the thermal diffusivity. This effect was confirmed by annealing the samples at 1573 K. The thermal diffusivities of the annealed samples measured at 1277, 1403 and 1531 K were found to be lower than the thermal diffusivities of non-annealed samples and the values did not show any noticeable change with time. It could be related to the attainment of equilibrium with the completion of the dissolution of γ and γ´ phases during the annealing process.

    Liquid CMSX-4 does not show any change of thermal diffusivity with temperature. It may be attributed to the decreasing the mean free path being shorter than characteristic distance between two neighbouring atoms.

    On the other hand thermal diffusivities of mould powder having glassy and crystalline states decrease with increasing temperature at lower temperature and are constant at higher temperature except for one glassy sample.

    Analogously, the thermal diffusivity measurements of mould powder did not show any significant change with temperature in liquid state. It is likely to be due to the silicate network being largely broken down.

    The thermal diffusivity is increased with increasing crystallisation degree of mould powder, which is expected from theoretical considerations.

    The coke sample, taken from deeper level of the blast furnace, is found to have larger thermal diffusivity. This could be correlated to the average crystallite size along the structural c-axis, Lc, which is indicative of the higher degree of graphitisation. This was also confirmed by XRD measurements of the different coke samples. The degree of graphitisation was found to increase with increasing temperature. Further, XRD measurements of coke samples taken from different levels in the shaft of the blast furnace show that the graphitisation of coke was instantaneous between room temperature and 1473 K.

  • 12. Abbas, Ghazanfar
    et al.
    Chaudhry, M. Ashraf
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Singh, Manish
    Liu, Qinghua
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Qin, Haiying
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Study of CuNiZnGdCe-Nanocomposite Anode for Low Temperature SOFC2012Ingår i: Nanoscience and Nanotechnology Letters, ISSN 1941-4900, Vol. 4, nr 4, s. 389-393Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Composite electrodes of Cu0.16Ni0.27Zn0.37Ce0.16Gd0.04 (CNZGC) oxides have been successfully synthesized by solid state reaction method as anode material for low temperature solid oxide fuel cell (LTSOFC). These electrodes are characterized by XRD followed by sintering at various time periods and temperatures. Particle size of optimized composition was calculated 40-85 nm and sintered at 800 degrees C for 4 hours. Electrical conductivity of 4.14 S/cm was obtained at a temperature of 550 degrees C by the 4-prob DC method. The activation energy was calculated 4 x 10(-2) eV at 550 degrees C. Hydrogen was used as fuel and air as oxidant at anode and cathode sides respectively. I-V/I-P curves were obtained in the temperature range of 400-550 degrees C. The maximum power density was achieved for 570 mW/cm(2) at 550 degrees C.

  • 13.
    Abbas, Ghazanfar
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. COMSATS Institute of Information Technology, Pakistan.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. COMSATS Institute of Information Technology, Pakistan.
    Ahmad, M. Ashfaq
    Khan, M. Ajmal
    Hussain, M. Jafar
    Ahmad, Mukhtar
    Aziz, Hammad
    Ahmad, Imran
    Batool, Rida
    Altaf, Faizah
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Electrochemical investigation of mixed metal oxide nanocomposite electrode for low temperature solid oxide fuel cell2017Ingår i: International Journal of Modern Physics B, ISSN 0217-9792, Vol. 31, nr 27, artikel-id 1750193Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Zinc-based nanostructured nickel (Ni) free metal oxide electrode material Zn-0.60/CU0.20Mn0.20 oxide (CMZO) was synthesized by solid state reaction and investigated for low temperature solid oxide fuel cell (LTSOFC) applications. The crystal structure and surface morphology of the synthesized electrode material were examined by XRD and SEM techniques respectively. The particle size of ZnO phase estimated by Scherer's equation was 31.50 nm. The maximum electrical conductivity was found to be 12.567 S/cm and 5.846 S/cm in hydrogen and air atmosphere, respectively at 600 degrees C. The activation energy of the CMZO material was also calculated from the DC conductivity data using Arrhenius plots and it was found to be 0.060 and 0.075 eV in hydrogen and air atmosphere, respectively. The CMZO electrode-based fuel cell was tested using carbonated samarium doped ceria composite (NSDC) electrolyte. The three layers 13 mm in diameter and 1 mm thickness of the symmetric fuel cell were fabricated by dry pressing. The maximum power density of 728.86 mW/cm(2) was measured at 550 degrees C.

  • 14.
    Abbas, Ghazanfar
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Ashfaq, M.
    Chaudhry, M. Ashraf
    Khan, Ajmal
    Ahmad, Imran
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Electrochemical study of nanostructured electrode for low-temperature solid oxide fuel cell (LTSOFC)2014Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 38, nr 4, s. 518-523Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Zn-based nanostructured Ba0.05Cu0.25Fe0.10Zn0.60O (BCFZ) oxide electrode material was synthesized by solid-state reaction for low-temperature solid oxide fuel cell. The cell was fabricated by sandwiching NK-CDC electrolyte between BCFZ electrodes by dry press technique, and its performance was assessed. The maximum power density of 741.87 mW-cm(-2) was achieved at 550 degrees C. The crystal structure and morphology were characterized by X-ray diffractometer (XRD) and SEM. The particle size was calculated to be 25 nm applying Scherer's formula from XRD data. Electronic conductivities were measured with the four-probe DC method under hydrogen and air atmosphere. AC Electrochemical Impedance Spectroscopy of the BCFZ oxide electrode was also measured in hydrogen atmosphere at 450 degrees C.

  • 15. Abbas, Ghazanfar
    et al.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi. COMSATS Institute of Information Technology, Pakistan .
    Chaudhry, M. A.
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Preparation and characterization of nanocomposite calcium doped ceria electrolyte with alkali carbonates (NK-CDC) for SOFC2010Ingår i: ASME 2010 8th International Conference on Fuel Cell Science, Engineering and Technology, FUELCELL 2010, ASME Press, 2010, s. 427-432Konferensbidrag (Refereegranskat)
    Abstract [en]

    The entire world's challenge is to find out the renewable energy sources due to rapid depletion of fossil fuels because of their high consumption. Solid Oxide Fuel Cells (SOFCs) are believed to be the best alternative source which converts chemical energy into electricity without combustion. Nanostructured study is required to develop highly ionic conductive electrolyte for SOFCs. In this work, the calcium doped ceria (Ce0.8Ca0.2O 1.9) coated with 20% molar ratio of two alkali carbonates (CDC-M: MCO3, where M= Na and K) electrolyte was prepared by co-precipitation method in this study. Ni based electrode was used to fabricate the cell by dry pressing technique. The crystal structure and surface morphology was characterized by X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM). The particle size was calculated in the range of 10-20nm by Scherrer's formula and compared with SEM and TEM results. The ionic conductivity was measured by using AC Electrochemical Impedance Spectroscopy (EIS) method. The activation energy was also evaluated. The performance of the cell was measured 0.567W/cm2 at temperature 550°C with hydrogen as a fuel.

  • 16.
    Abbas, Ghazanfar
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Chaudhry, M. Ashraf
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Preparation and Characterization of Nanocomposite Calcium Doped Ceria Electrolyte With Alkali Carbonates (NK-CDC) for SOFC2011Ingår i: Journal of Fuel Cell Science and Technology, ISSN 1550-624X, Vol. 8, nr 4, s. 041013-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The entire world's challenge is to find out the renewable energy sources due to rapid depletion of fossil fuels because of their high consumption. Solid oxide fuel cells (SOFCs) are believed to be the best alternative source, which converts chemical energy into electricity without combustion. Nanostructure study is required to develop highly ionic conductive electrolytes for SOFCs. In this work, the calcium doped ceria (Ce0.8Ca0.2O1.9) coated with 20% molar ratio of two alkali carbonates (CDC-M: MCO3, where M = Na and K) electrolyte was prepared by coprecipitation method. Ni based electrode was used to fabricate the cell by dry pressing technique. The crystal structure and surface morphology were characterized by an X-ray diffractometer, scanning electron microscopy (SEM), and high resolution transmission electron microscopy (TEM). The particle size was calculated in the range 10-20 nm by Scherer's formula and compared with SEM and TEM results. The ionic conductivity was measured by using ac electrochemical impedance spectroscopy method. The activation energy was also evaluated. The performance of the cell was measured 0.567 W/cm(2) at temperature 550 degrees C with hydrogen as a fuel.

  • 17.
    Abbas, Ghazanfar
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi. COMSATS Institute of Information Technology, Pakistan.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi. COMSATS Institute of Information Technology, Pakistan.
    Khan, M. Ajmal
    Ahmad, Imran
    Chaudhry, M. Ashraf
    Sherazi, Tauqir A.
    Mohsin, Munazza
    Ahmad, Mukhtar
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Synthesize and characterization of nanocomposite anodes for low temperature solid oxide fuel cell2015Ingår i: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 40, nr 1, s. 891-897Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solid oxide fuel cells have much capability to become an economical alternative energy conversion technology having appropriate materials that can be operated at comparatively low temperature in the range of 400-600 degrees C. The nano-scale engineering has been incorporated to improve the catalytic activity of anode materials for solid oxide fuel cells. Nanostructured Al0.10NixZn0.90-xO oxides were prepared by solid state reaction, which were then mixed with the prepared Gadolinium doped Ceria GDC electrolyte. The crystal structure and surface morphology were characterized by XRD and SEM. The particle size was evaluated by XRD data and found in the range of 20-50 nm, which was then ensured by SEM pictures. The pellets of 13 mm diameter were pressed by dry press technique and electrical conductivities (DC and AC) were determined by four probe techniques and the values have been found to be 10.84 and 4.88 S/cm, respectively at hydrogen atmosphere in the temperature range of 300-600 degrees C. The Electrochemical Impedance Spectroscopy (EIS) analysis exhibits the pure electronic behavior at hydrogen atmosphere. The maximum power density of ANZ-GDC composite anode based solid oxide fuel cell has been achieved 705 mW/cm(2) at 550 degrees C.

  • 18.
    Abbas, Maryam
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekonomi och organisation (Inst.).
    Knowledge Management vid uppdragsarbete2011Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
  • 19.
    Abbas Sohani, Amir
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Waste heat recovery from SSAB’s Steel plant in Oxelösund using a Heat Pump2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Detta projekt är inriktat på spillvärmepotentialer inom järn och stålindustrin. Högtemperaturvärme-pumpar för medelvarma temperaturkällor har modellerats. SSABs stålverk i Oxelusund har använts som exempel. Järn- och stålindustrin i Sverige är storkonsument av energi, tillsammans med pappers och massaindustrin. Det finns också en stor potential för spillvärmeåtervinning i stålindustrin. Det görs redan i Luleå t ex [1].

    Järn och stålindustrins produktionsmetoder och spillvärmeåtervinning, speciellt i USA och Sverige har studerats genom en litteraturstudie. Dagens metoder och potentialer för spillvärmeåtervinning inom järn och stålindustrin i Sverige studerades speciellt. SSABs anläggning i Oxelösund, har i decennier planerat inte bara att värma Oxelösunds stad som idag, utan också expandera till näraliggande Nyköping bara 12 km bort [2].

    Typiskt är den maximala framledningstemperaturen till Nyköpings fjärrvärmenät 110 °C den kallaste dagen. En spillvärme-värmepump når normalt inte upp till så höga temperaturer. Dock räcker 80 °C maximal framledningstemperatur från värmepumpen för att nyttiggöra spillvärmekällan kontinuerligt. Även en lägre temperatur som 75 °C skulle sannolikt räcka. Bara några få fjärrvärme-värmeväxlare i några hus skulle behöva bytas för att denna lägre temperatur skulle räcka till. De överskjutande graderna mellan 80 °C (75 °C) och 110 °C kan tas med värme från t ex existerande biobränslepannor lokalt i Nyköping.

    Att använda värmepumpar i detta sammanhang är inte självskrivet. Generellt är värmeflödena från ett stålverk så högtempererade att ingen värmpump behövs. Om man försöker komma åt dessa högtemperaturflöden i en gammal anläggning kan det bli väldigt dyrt och störa produktionen. Därför

    koncentrerades studien på medeltemperaturkällor (30 °C till 40 °C) och användande av högtemperaturvärmepumpar. Sådan värme dumpas nu med kyltorn. På så sätt kan 50 % av Nyköpings värmebehov tillgodoses med lätt tillgänglig spillvärme. Om man antar en värmefaktor på cirka 5, och lägger till värmepumpens förbrukade elektricitet blir det 62 % av Nyköpings fjärrvärmebehov.

    Oxelösundanläggningen är bara ett exempel och studien fokuseras på högtemperaturs-industriella värmepumpar HITIHP för sådana här och liknande användningar. Lämpliga komponenter och köldmedia har undersökts och generella konstruktionsprinciper av HITIHP föreslås. En litteraturstudie för att finna de bästa HITIHP-köldmedierna har gjorts.

    En tvåstegs högtemperaturvärmepump, som använder den tillgängliga värmekällans kapacitet och temperaturer tillsammans med fjärrvärmenätets krav, har modellerats och simulerats. Simuleringen har huvudsakligen gjorts med programmet EES. R245fa har t ex visat sig vara lämpligt som köldmedium i det andra steget av en högtemperaturvärmepump. Med R245fa kan till och med högre temperaturer än 90 °C uppnås till fjärrvärmesystemet. Tidigare skulle R134a ha använts i en sådan här applikation, men R245fa har t e lägre GWP (Global Warming Potential omkring 1000 istället för omkring 1300)[3]. Många olika köldmedia har simulerats i lågtemperatursteget av värmepumpen som initialt antogs vara en skruvkompressor-kaskad-värmepump. En större värmpump med två turbokompressorsteg och flashtank har också simulerats. Den gav också tillfredställande resultat. I det senare fallet studerades både R1234ZE(z) och R245fa som gav goda resultat men R1234ZE(z) ger mycket lägre GWP.

    Alla värmefaktorer (COP, energibehov, kondensortryck och tryckförhållanden (hög-/lågtryck) jämfördes. R245fa-R245fa och R600a-R245fa studerades noga i tvåstegs-kaskad-systemet med skruvkompressor. Dessa kombinationer gav bäst resultat. R717-R245fa var också bra men hade andra begränsningar. I tvåstegssystem med turbokompressorer och flashtank visade sig visade sig R1234ZE(z) ge gen bästa värmefaktorn. Man hade naturligtvis inte heller något temperaturfall i någon värmeväxlare mellan de två stegen. Om SSABs spillvärme av någon anledning inte skulle vara tillgängligt kan en sådan värmpump istället använda havsvatten som värmekälla.

    Begränsningen av koldioxidutsläppen är mycket svåra att beräkna. Detta kommer att bero mer på politisk övertygelse än på lättbevisade fakta. En mycket grov beräkning av kostnaden har också gjorts. Uppskattningsvis kommer projektet att kosta mellan 420 och 450 MSEK. Kostnadsuppskattningen inkluderar värmepumpen och en 12 km lång förbindelse till Nyköping. Kostnaden för värme levererad till Nyköping, kommer att variera mellan 0,2 kr/kWh och 0,65 kr/kWh när elpriset varieras mellan 0,5 och 2 SEK/kWh. Den högre värmkostnaden 0,65 kr/kWh beror också på att östersjövatten – inte spillvärme används som värmekälla.

    Värme från ett kyltorn kan återvinnas med en högtemperaturvärmepump. Den kan levereras från Oxelösund till Nyköping. De ekonomiska detaljerna har bar studerats översiktligt. Faktorer som om renovering den gamla pannan i Nyköping eller SSABs kyltorn kunde senareläggas, skulle kunna förbättra intresset för projektet. Ett spillvärmerör mellan Oxelösund och Nyköping har studerats sedan mitten av 70-talet av t ex Lars-Åke Cronholm [4]. Kan det vara dags nu?

  • 20.
    ABBAS, THOALFIQAR
    KTH, Skolan för industriell teknik och management (ITM), Tillämpad maskinteknik (KTH Södertälje).
    Utforma en monteringslina för solfångare2014Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
  • 21. Abbasalizadeh, A.
    et al.
    Sridar, S.
    Chen, Z.
    Sluiter, M.
    Yang, Y.
    Sietsma, J.
    Seetharaman, Seshadri
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Hari Kumar, K. C.
    Experimental investigation and thermodynamic modelling of LiF-NdF3-DyF3 system2018Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 753, s. 388-394Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electrolysis of molten fluorides is one of the promising methods for the recovery and recycling of rare earth metals from used magnets. Due to the dearth of phase equilibria data for molten fluoride systems, thermodynamic modelling of LiF-DyF3-NdF3 system using the CALPHAD approach was carried out. Gibbs energy modelling for LiF-NdF3 and LiF-DyF3 systems was performed using the constitutional data from literature. Ab initio calculations were used to obtain enthalpy of reaction of LiDyF4, an intermediate phase that is found to exist in the LiF-DyF3 system. Differential thermal analysis was carried out for selected compositions in the NdF3-DyF3 system, in order to determine liquidus and solidus temperatures. The Gibbs energy parameters for the limiting binaries determined in this work is used for modelling the Gibbs energy functions of equilibrium phases in the ternary system. Selected compositions of LiF-NdF3-DyF3 were subjected to DTA in order to validate the calculated phase temperatures involving melt.

  • 22. Abbasalizadeh, A.
    et al.
    Teng, Lidong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Seetharaman, Seshadri
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Sietsma, J.
    Yang, Y.
    Rare Earth Extraction from NdFeB Magnets and Rare Earth Oxides Using Aluminum Chloride/Fluoride Molten Salts2015Ingår i: Rare Earths Industry: Technological, Economic, and Environmental Implications, Elsevier, 2015, s. 357-373Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    In the current research, the feasibility of the recovery of neodymium and dysprosium from spent NdFeB magnets (about 6wt% Dy) was investigated using molten salt processes. The salt bath consisted of a eutectic composition of an NaCl-KCl-LiCl mixture. To enable the efficient dissolution of metal in the molten salt phase, AlCl3 was used as a chlorinating agent. Iron-free electrodeposition was carried out successfully. Energy-dispersive spectroscopic analysis of the electrodeposit revealed that co-deposition of the dysprosium occurs along with neodymium at the cathode. The process shows that this method is well suited for recovering rare earth metals from magnetic scrap containing these metals.Furthermore, the setup design for recovery of neodymium and dysprosium from their oxides was investigated with regard to previous studies on the neodymium magnets. The stability of different fluoride and chloride salts was studied by means of thermodynamic calculation. Aluminum fluoride-based molten salt systems were studied in detail as the electrolyte for electrochemical extraction of rare earth oxides into rare earth metal elements with Al.

  • 23. Abbasalizadeh, Aida
    et al.
    Malfliet, Annelies
    Seetharaman, Seshadri
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Sietsma, Jilt
    Yang, Yongxiang
    Electrochemical Extraction of Rare Earth Metals in Molten Fluorides: Conversion of Rare Earth Oxides into Rare Earth Fluorides Using Fluoride Additives2017Ingår i: JOURNAL OF SUSTAINABLE METALLURGY, ISSN 2199-3823, Vol. 3, nr 3, s. 627-637Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present research on rare earth extraction from rare earth oxides (REOs), conversion of rare earth oxides into rare earth fluorides with fluoride fluxes is investigated in order to overcome the problem of low solubility of the rare earth oxides in molten fluoride salts as well as the formation of oxyfluorides in the fluorination process. Based on thermodynamic calculations, a series of experiments were performed for converting the rare earth oxides into rare earth fluorides using AlF3, ZnF2, FeF3, and Na3AlF6 as fluorinating agents in a LiF-Nd2O3 system. The formation of neodymium fluoride as a result of the reactions between these fluxes and neodymium oxide is confirmed. The rare earth fluoride thus formed can subsequently be processed through the electrolysis route in the same reactor, and rare earth metal can be produced as the cathodic deposit. In this concept, the REO dissolution in molten fluorides would become unnecessary due to the complete conversion of the oxide into the fluoride, REF3. The results of XRD and EPMA analysis of the reacted samples indicate that AlF3, ZnF2, and FeF3 can act as strong fluorinating agents for the neodymium oxide giving rise to a complete conversion of neodymium oxide into neodymium fluoride.

  • 24. Abbasalizadeh, Aida
    et al.
    Malfliet, Annelies
    Seetharaman, Seshadri
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Sietsma, Jilt
    Yang, Yongxiang
    Electrochemical Recovery of Rare Earth Elements from Magnets: Conversion of Rare Earth Based Metals into Rare Earth Fluorides in Molten Salts2017Ingår i: Materials transactions, ISSN 1345-9678, E-ISSN 1347-5320, Vol. 58, nr 3, s. 400-405Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present work, selective extraction of rare earth (RE) metals from NdFeB magnets is investigated by studying the effects of various fluxes, viz. AlF3, ZnF2, FeF3 and Na3AlF6 in the LiF-NdFeB system. The aim is to convert RE from RE magnet into the fluoride salt melt. The results show the complete selective separation of neodymium (also dysprosium) from the magnet and formation of rare earth fluoride, leaving iron and boron unreacted. The formed rare earth fluoride can subsequently be processed in the same reactor through an electrolysis route so that RE can be deposited as a cathode product. The results of XRD and EPMA analysis of the reacted samples indicate that AlF3, ZnF2 and FeF3 can act as strong fluorinating agents for extraction of rare earth from NdFeB magnet, converting the RE to REF3. The results confirm the feasibility of the rare earth metals recovery from scrap NdFeB magnet as raw material. The fluoride conversion- electrolysis route suggested in the present work enables the extraction of rare earth metals in a single step using the above-mentioned fluxes.

  • 25.
    Abbasalizadeh, Aida
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Seetharaman, Seshadri
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Teng, Lidong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Sridhar, Seetharaman
    Grinder, Olle
    Izumi, Yukari
    Barati, Mansoor
    Highlights of the Salt Extraction Process2013Ingår i: JOM: The Member Journal of TMS, ISSN 1047-4838, E-ISSN 1543-1851, Vol. 65, nr 11, s. 1552-1558Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article presents the salient features of a new process for the recovery of metal values from secondary sources and waste materials such as slag and flue dusts. It is also feasible in extracting metals such as nickel and cobalt from ores that normally are difficult to enrich and process metallurgically. The salt extraction process is based on extraction of the metals from the raw materials by a molten salt bath consisting of NaCl, LiCl, and KCl corresponding to the eutectic composition with AlCl3 as the chlorinating agent. The process is operated in the temperature range 973 K (700 degrees C) to 1173 K (900 degrees C). The process was shown to be successful in extracting Cr and Fe from electric arc furnace (EAF) slag. Electrolytic copper could be produced from copper concentrate based on chalcopyrite in a single step. Conducting the process in oxygen-free atmosphere, sulfur could be captured in the elemental form. The method proved to be successful in extracting lead from spent cathode ray tubes. In order to prevent the loss of AlCl3 in the vapor form and also chlorine gas emission at the cathode during the electrolysis, liquid aluminum was used. The process was shown to be successful in extracting Nd and Dy from magnetic scrap. The method is a highly promising process route for the recovery of strategic metals. It also has the added advantage of being environmentally friendly.

  • 26. Abbasalizadeh, Aida
    et al.
    Seetharaman, Seshadri
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Venkatesan, Prakash
    Sietsma, Jilt
    Yang, Yongxiang
    Novel Reactive Anode for Electrochemical Extraction of Rare Earth Metals from Rare Earth Oxides2017Ingår i: RARE METAL TECHNOLOGY 2017 / [ed] Kim, H Alam, S Neelameggham, NR Oosterhof, H Ouchi, T Guan, X, SPRINGER INTERNATIONAL PUBLISHING AG , 2017, s. 87-92Konferensbidrag (Refereegranskat)
    Abstract [en]

    Electrolytic production of metallic neodymium is carried out in fused fluoride salts containing neodymium oxide. Two major challenges pertaining to neodymium production are (a) low oxide solubility, (b) possibility of anodic fluorine gas evolution if the electrolysis rate exceeds feeding rate of neodymium oxide. In this study, a novel method is proposed in which iron fluoride (FeF3) is used as a fluorinating agent to convert neodymium oxide into neodymium fluoride. Electron Probe Micro Analysis (EPMA) results of as-converted salt show a complete conversion of neodymium oxide into neodymium fluoride. In the electrolysis process, iron is used as a reactive anode with electrochemical dissolution of iron into the melt, thus preventing fluorine gas evolution at the anode. Therefore, the fluorinating agent is constantly regenerated in situ which enables the continuous conversion of neodymium oxide feed. The cathodic product is a Nd-Fe alloy which can be directly used as a master alloy for the production of NdFeB permanent magnets.

  • 27.
    Abbasalizadeh, Aida
    et al.
    Delft Univ Technol TU Delft, Dept Mat Sci & Engn, Mekelweg 2, NL-2628 CD Delft, Netherlands..
    Seetharaman, Seshadri
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Venkatesan, Prakash
    Delft Univ Technol TU Delft, Dept Mat Sci & Engn, Mekelweg 2, NL-2628 CD Delft, Netherlands..
    Sietsma, Jilt
    Delft Univ Technol TU Delft, Dept Mat Sci & Engn, Mekelweg 2, NL-2628 CD Delft, Netherlands..
    Yang, Yongxiang
    Delft Univ Technol TU Delft, Dept Mat Sci & Engn, Mekelweg 2, NL-2628 CD Delft, Netherlands..
    Use of iron reactive anode in electrowinning of neodymium from neodymium oxide2019Ingår i: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 310, s. 146-152Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electrolytic production of metallic neodymium is carried out in fused neodymium fluoride salts containing neodymium oxide. Two major challenges pertaining to neodymium production in fluoride salts are a) low solubility of neodymium oxide in fluoride melt, b) possibility of anodic gas evolution (CO, CO2, CF4, C2F6). In this study, iron is used as a reactive anode in the electrolysis process, promoting electrochemical dissolution of iron into the melt, preventing PFC (perfluorocarbon) gas evolution at the anode. Further, the rare earth oxide is converted to rare earth fluoride by the use of iron fluoride formed as the result of iron dissolution. Thus, the fluoridizing agent is constantly regenerated in-situ which enables the continuous conversion of neodymium oxide feed. The cathodic product is Nd-Fe alloy which can be used as a master alloy for the production of NdFeB magnets. 

  • 28.
    Abbasalizadeh, Aida
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Teng, Lidong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Seetharaman, S.
    Dysprosium extraction using molten salt process2014Ingår i: Rare metal technology 2014: proceedings of a symposium sponsored by The Minerals, Metals & Materials Society (TMS) held during TMS 2014, 143rd Annual Meeting & Exhibition, February 16-20, 2014, San Diego Convention Center, San Diego, California, USA, 2014, s. 207-208Konferensbidrag (Refereegranskat)
  • 29.
    Abbasalizadeh, Aida
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Teng, Lidong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Sridhar, S.
    Seetharaman, Seshadri
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Neodymium extraction using salt extraction process2015Ingår i: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 124, nr 4, s. 191-198Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present paper deals with the feasibility of the neodymium recovery from spent Nd-Fe-B magnets using molten salt electrodeposition method. The salt bath consisted of a mixture of LiCl- KCl-NaCl corresponding to the eutectic composition. The experimental set-up with its salient features is presented. AlCl3 was used as flux and graphite rods dipped in the salt bath served as electrodes. The voltage for the electrolysis was chosen on the basis of the decomposition potential of NdCl3. The reaction sequence can be described as Iron-free neodymium deposition could be carried out successfully. In view of the proximity of the electrode potentials, the co-deposition of the aluminium and neodymium was observed to occur at the cathode, as revealed by SEM/EDS and XRD analyses of the electrodeposit.

  • 30.
    Abbasi, Abdul Ghafoor
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Muftic, Sead
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    CryptoNET: Security Management Protocols2010Ingår i: ADVANCES IN DATA NETWORKS, COMMUNICATIONS, COMPUTERS / [ed] Mastorakis, NE; Mladenov, V, ATHENS: WORLD SCIENTIFIC AND ENGINEERING ACAD AND SOC , 2010, s. 15-20Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we describe several network security protocols used by various components of CryptoNET architecture. The protocols are based on the concept of generic security objects and on well-established security standards and technologies. Distinctive features of our security protocols are: (1) they are complete in terms of their functionality, (2) they are easy to integrate with applications, (3) they transparently handle security credentials and protocol-specific attributes using FIPS 201 (PIV) smart cards, and (4) they are based on generic security objects. These protocols are: remote user authentication protocol, single-sign-on protocol, SAML authorization protocol, and secure sessions protocol. Security protocols use our Security Provider as a collection of cryptographic engines implemented either in software or using FIPS 201 (NV) smart cards. It also manages protocols' attributes using security applets stored in Ply smart card.

  • 31.
    Abbasi, Saeed
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    A comparison between particle characteristics between two railway brake pads2013Rapport (Övrigt vetenskapligt)
  • 32.
    Abbasi, Saeed
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    A study of nanostructured particles in railway tunnels2013Rapport (Övrigt vetenskapligt)
  • 33.
    Abbasi, Saeed
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Characterisation of airborne particles from rail traffic2011Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Since the investigation of wear particles in rail transport started in late-1910s, the high mass concentration of these particles has raised worries among researchers concerned with air quality. However, effective action has yet to be taken because of lack of relevant knowledge. This thesis provides applicable information for the airborne wear particles in rail transport. Some aspects of their characteristics such as diameter size, mass concentration, number concentration, and morphology of particles were investigated in field tests and laboratory tests.The effects on particle characterisations from different operational conditions in the field tests, and applying different braking materials, conducting tests in different applied loads or sliding velocities in the laboratory tests were studied. The main advantage of conducting laboratory tests was to focus on studying particles from one source. The possibility of repetition, using high sensitive instruments and conducting tests at low costs are the other advantages of laboratory studies. Paper A describes how a pin-on-disc machine was used to reproduce similar real operational conditions during mechanical braking in a train. The results were validated by comparing the field tests results with the laboratory studies. The particles morphology and size distribution were also studied.Paper B presents a summary of field tests results. The effects of curve negotiating and applying braking in different real conditions were investigated with an on-board measurement.The element composition of the particles and their potential sources were also investigated outside of the particles morphologies.Paper C presents comprehensive results from laboratory studies on airborne particles from different braking materials. The differences in the particle characteristics in similar test conditions were attributable to different material compositions and dominant wear mechanisms. A new index was introduced in this paper and is suggested to be used as a qualitative factor with regard to the airborne wear particle emission rate.Paper D is a review of the recent studies of exhaust emission and non-exhaust emission from rail vehicles. A summary of results, measurements, adverse health effects, and proposed or applied solutions are reviewed in this paper.

  • 34.
    Abbasi, Saeed
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Nanostructured particles in/outside compartment of running train, an on board measurement2013Rapport (Övrigt vetenskapligt)
  • 35.
    Abbasi, Saeed
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Non-exhaust Nano particle emission in Rail traffic2010Konferensbidrag (Refereegranskat)
  • 36.
    Abbasi, Saeed
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Towards elimination of airborne particles from rail traffic2013Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Since the investigation of wear particles from rail transport started in the late 1910s, the high mass concentrations of these particles have prompted concern among researchers interested in air quality. However, effective action has yet to be taken because relevant knowledge is still missing. This thesis provides knowledge of airborne wear particles originating from rail transport. Some aspects of their characteristic parameters, such as size, mass concentration, number concentration, and morphology, were investigated in the field and in laboratory tests. We also discuss means to mitigate non-exhaust emissions, as well as the advantages and disadvantages of various test set-ups in the seven appended journal papers:Paper A reviews recent studies of exhaust and non-exhaust emissions from rail vehicles. The results, measurements, adverse health effects, and proposed or applied solutions presented in this literature are summarized in this paper.Paper B summarizes the results of field tests we conducted. The effects of curve negotiation and braking under different real conditions were investigated in a field test in which on-board measurements were made. The elemental composition and morphology of the particles emitted and their potential sources were also investigated.Paper C describes how a pin-on-disc machine can be used to reproduce real operating conditions during mechanical train braking in a controlled laboratory setting. The results were validated by comparing the field test results with the results of laboratory studies.Paper D presents comprehensive results of laboratory studies of airborne particles from different braking materials. A new index is introduced in this paper, which can be used as a quantitative metric for assessing airborne wear particle emission rates.Paper E describes the effects of using various friction modifiers and lubricants on the characteristics of airborne particles from wheel–rail contact under lubricated and unlubricated conditions.Paper F reports work to simulate thermoelastic instability in the cast-iron braking material. We simulated the fluctuation of the flash temperature by considering the temperature dependency of the material properties and the transformation of the contact state due to thermomechanical phenomena and wear.Paper G reviews new full- and sub-scale measurements of non-exhaust emissions from ground transport. The advantages and disadvantages of on-board measurements, pin-on-disc tests, dynamometer tests, and test rig studies are discussed in this paper.

  • 37.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Ekstrand-Hammarström, Barbara
    Division of CBRN Defence and Security, Swedish Defence Research Agency (FOI),.
    Bergström, Ulrika
    Division of CBRN Defence and Security, Swedish Defence Research Agency (FOI),.
    Bucht, Anders
    Deptartment of Public Health and Clinical Medicine, Umeå University Hospital, Umeå, 901 89, Sweden.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Sellgren, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Jansson, Anders
    Department of Applied Environmental Science, Stockholm University, Stockholm, 106 91, Sweden.
    Biological response in lung cells by brake dust from a novel set-up to generate one sourcewear particles2013Konferensbidrag (Refereegranskat)
  • 38.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Jansson, Anders
    Stockholm University, Applied Environmental Science, Stockholm, Sweden.
    Olander, Lars
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Installationsteknik.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Sellgren, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    A pin-on-disc study of the rate of airborne wear particle emissions from railway braking materials2012Ingår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 284, s. 18-29Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The current study investigates the characteristics of particles generated from the wear of braking materials, and provides an applicable index for measuring and comparing wear particle emissions. A pin-on-disc tribometer equipped with particle measurement instruments was used. The number concentration, size, morphology, and mass concentration of generated particles were investigated and reported for particles 10 nm-32 mu m in diameter. The particles were also collected on filters and investigated using EDS and SEM. The effects of wear mechanisms on particle morphology and changes in particle concentration are discussed. A new index, the airborne wear particle emission rate (AWPER), is suggested that could be used in legislation to control non-exhaust emissions from transport modes, particularly rail transport.

  • 39.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Jansson, Anders
    Sellgren, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Particle emissions from rail traffic: a literature review2013Ingår i: Critical reviews in environmental science and technology, ISSN 1064-3389, E-ISSN 1547-6537, Vol. 43, nr 23, s. 2211-2244Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Particle emissions are a drawback of rail transport. This work is a comprehensive presentation of recent research into particle emissions from rail vehicles. Both exhaust and non-exhaust particle emissions are considered when examining particle characteristics such as  PM10, and PM2.5 concentration levels, size, morphology, composition, as well as adverse health effects, current legislation, and available and proposed solutions for reducing such emissions. High concentration levels in enclosed rail traffic environments are reported and some toxic effects of the particles. We find that only a few limited studies have examined the adverse health effects of non-exhaust particle emissions and that no relevant legislation exists. Thus further research in this area is warranted.

  • 40.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Moslemi, Kianoush
    A new approach for optimization of heating system in tank wagons2003Konferensbidrag (Refereegranskat)
  • 41.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Olander, Lars
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Installationsteknik.
    Larsson, Christina
    Bombardier Transportation Sweden AB, Västerås, Sweden.
    Jansson, Anders
    Stockholm University, Applied Environmental Science, Stockholm, Sweden.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Tribologi.
    Sellgren, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    A field test study of airborne wear particles from a running regional train2012Ingår i: IMechE, Part F: Journal of Rail and Rapid Transit, ISSN 0954-4097, Vol. 226, nr 1, s. 95-109Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Inhalable airborne particles have inverse health affect. In railways, mechanical brakes, the wheel–rail contact, current collectors, ballast, sleepers, and masonry structures yield particulate matter. Field tests examined a Swedish track using a train instrumented with particle measurement devices, brake pad temperature sensors, and speed and brake sensors. The main objective of this field test was to study the characteristics of particles generated from disc brakes on a running train with an on-board measuring set-up.

    Two airborne particle sampling points were designated, one near a pad–rotor disc brake contact and a second under the frame, not near a mechanical brake or the wheel–rail contact; the numbers and size distributions of the particles detected were registered and evaluated under various conditions (e.g. activating/deactivating electrical brakes or negotiating curves). During braking, three speed/temperature-dependent particle peaks were identified in the fine region, representing particles 280 nm, 350 nm, and 600 nm in diameter. In the coarse region, a peak was discerned for particles 3–6 μm in diameter. Effects of brake pad temperature on particle size distribution were also investigated. Results indicate that the 280 nm peak increased with increasing temperature, and that electrical braking significantly reduced airborne particle numbers. FESEM images captured particles sizing down to 50 nm. The ICP-MS results indicated that Fe, Cu, Zn, Al, Ca, and Mg were the main elements constituting the particles.

     

  • 42.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Sellgren, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    A study of friction modifiers on airborne wear particles from wheel-rail contact2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Wheel-rail contact and its wear process are crucial issues in maintenance and operating of rolling stocks. During wheel-rail contact, materials in mating faces are worn off and some of them transferred to airborne particles. Eventhough the wear process in wheel-rail contact are well-known, few studies have been conducted on the airborne particles from wheel-rail contact.

    The purpose of this study is to investigate the effect of using different friction modifier on the amount of airbotne particles from wheel-rail contact in a laboratory simulation. In this regard, a series laboratory tests were used by using round head pin (R=25mm) and dead weight 40 N in a pin-on-disc machine. This set-up simulates a contact pressure around 750 MPa on the pin head.

    The amount of airborne particles and their characteristics were investigated in dry-contact, and non-dry contacts whereas a lubricant, Binol rail 510 and a friction modifier, tramsilence were used. According to the results, the effects of using Binol rail to reduce the amount of airborne particles were considerable.

  • 43.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Sellgren, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Airborne wear particles from train traffic2010Konferensbidrag (Refereegranskat)
  • 44.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Sellgren, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Experiences of measuring airborne wear particles from braking materials and the wheel - Rail contact2012Ingår i: 9th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, CM 2012, Southwest Jiaotong University , 2012, s. 608-609Konferensbidrag (Refereegranskat)
    Abstract [en]

    During braking both of the discs and pads of disc brakes are worn. Since disc brakes are not sealed, some of the generated wear particles can become airborne. The same condition also holds for block brakes utilized in rail vehicles. Furthermore, the wheel-rail contact is also subjected to wear processes during braking as well as during normal running. This contact also contributes to generation of airborne particles. Several studies have found an association between adverse health effects and the concentration of particles in the atmosphere, so it is of interest to improve our knowledge of the airborne wear particles. The present work includes results from full scale testing of rail vehicles. Particle size distribution, morphology and elemental contents are presented and discussed. Due to high back ground concentration levels in field tests, dedicated laboratory test set ups on a reduced scale were designed and utilized for airborne particle studies with zero background level. Promising correlation between field test and the lab set up is identified. Different ways of using this test set up for evaluating how the composition of the airborne particles is classified with respect to their health effects are discussed. Furthermore, different ways of using the proposed method to rank and to quantify airborne particle emission factors are presented.

  • 45.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Sellgren, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Experiences of measuring airborne wear particles from braking materials and wheel-rail contact2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    During braking both of the discs and pads of disc brakes are worn. Since disc brakes are not sealed, some of the generated wear particles can become airborne.  Wheel-rail is also subjected to wear process during braking as well as normal running. They also contribute to generate airborne particles. Several studies have found an association between adverse health effects and the concentration of particles in the atmosphere, so it is of interest to improve our knowledge of the airborne wear particles generated by disc brakes.

    The present work includes results from full scale testing of rail vehicles. Particle size distribution, morphology and elemental contents are presented and discussed for different combinations of disc and pad materials. Due to high back ground concentration levels in field tests, dedicated laboratory test set ups on a reduced scale were designed and utilized for airborne particle studies with zero background level.

    Promising correlation between field test and the lab set up is identified. Different ways of using this test set up for evaluating how the composition of the airborne particles is classified with respect to their health effects are discussed. Furthermore, different ways of using the proposed method to rank and to quantify airborne particle emission factors are presented.

  • 46.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Sellgren, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Lack of applicable criteria in non-exhaust emission legislation: AWPER index a practical solution2011Konferensbidrag (Refereegranskat)
  • 47.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Sellgren, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Olander, Lars
    A field investigation of the size and morphology and chemical composition of airborne particles in rail transport2010Konferensbidrag (Refereegranskat)
  • 48.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Sellgren, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Olander, Lars
    Larsson, christina
    A field investigation of the size, morphology and chemical composition of airborne particles in rail transport2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    The health effects of inhalable airborne particles are well documented. In the European Union the European Council mandates that the level of airborne particles with a diameter smaller than 10 µm (PM10) must not exceed an annual average of 40 µg/m3. Examples of possible sources from rail transport are mechanical brakes, wheel rail contact, current collectors, ballast, sleepers and masonry structures. In this regard, a series of field tests have been conducted on a regular Swedish track using a regional train instrumented with: particle measurement devices, temperature sensors in brake pads and sensors to measure the magnitude of train speed and a GPS.

    Two sampling points for airborne particles were designated in the train under frame. One of the sampling points was near a pad to rotor disc brake contact and a second global sampling point was chosen under the frame, but not near a mechanical brake or the wheel-rail contact. The first one was highly influenced by brake pad wear debris and the other one was influenced by all of the brake pads, wheel and rail wear debris as well as re-suspension. In each sampling points, three tubes were linked to three particle measurement devices. Two sets of Ptrak, Dustrak and Grimm devices were used. The Ptrak 8525 was an optical particle measurement device which could measure particle diameter in the size interval of 20 nm up to 1 micrometer. The Dustrak was used to measure particle mass concentration. The Grimm 1.109 was an aerosol spectrometer which counted number of particles from 0.25 micrometer to 32 micrometer in 31 intervals. These two Grimm devices were equipped with Millipore filters in the devices outlets to capture particles for further studies on morphology and matter of particles.

    The total number and size distribution of the particles for these two sampling points were registered and evaluated in different situations such as activating and deactivating electrical brake or train curve negotiating.

    During braking, three peaks of 250 nm, 350 nm and 600 nm in diameter, with the 350 nm peak dominating were identified in the fine particle region. In the coarse particle region, a peak of around 3-6 µm in diameter was discovered. The brake pad temperature effects on particle size distribution were also investigated and the results showed that the peak around 250 nm increased. Furthermore, the activation of electrical braking significantly reduced the number of airborne particles.

    A SEM was used to capture the images from collected particles on filters. Furthermore, an ICP-Ms method was used to investigate the elemental contents of the particulates on the filter.  In this case the main contribution belonged to Fe, Si, Al, Ca, Cu, Zn. The higher amount of some elements weights such as calcium, silicon, sodium and aluminum in the global sampling point filters revealed that ballast and concrete sleepers were the main sources for these particles although some of them originated from rail, wheel, brake disc and brake pad as well.

  • 49.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Tritscher, Trosten
    TSI.
    Krinke, Thomas
    TSI.
    On-board study of nano- and micrometer-particle characteristics of a running electric train2013Konferensbidrag (Refereegranskat)
  • 50.
    Abbasi, Saeed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Olofsson, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Zhu, Yi
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Sellgren, Ulf
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Maskinelement.
    Pin-on-disc study of the effects of railway friction modifiers on airborne wear particles from wheel-rail contact2013Ingår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 60, s. 136-139Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Knowledge of wheel–rail interaction is crucial to wheel and rail maintenance. In this interaction, some of theworn-off material is transformed into airborne particles. Although such wear is well understood, few studiestreat the particles generated. We investigated friction modifiers' effects on airborne particles characteristicsgenerated in wheel-rail contacts in laboratory conditions. Pin-on-disc machine testing with a round-head pinloaded by a dead weight load 40 N simulated maximum contact pressure over 550 MPa. Airborne particlecharacteristics were investigated in dry contacts and in ones lubricated with biodegradable rail grease andwater- and oil-based friction modifiers. The number of particles declined with the grease; the number ofultrafine particles increased with the water-based friction modifier, mainly due to water vaporization.

1234567 1 - 50 av 16948
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf