Ändra sökning
Avgränsa sökresultatet
1234567 1 - 50 av 1845
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • 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. Hosseini, V.
    et al.
    Karlsson, L.
    Örnek, Cem
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Swerea KIMAB AB.
    Reccagni, P.
    Wessman, S.
    Engelberg, D.
    Microstructure and functionality of a uniquely graded super duplex stainless steel designed by a novel arc heat treatment method2018Ingår i: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 139, s. 390-400Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel arc heat treatment technique was applied to design a uniquely graded super duplex stainless steel (SDSS), by subjecting a single sample to a steady state temperature gradient for 10 h. A new experimental approach was used to map precipitation in microstructure, covering aging temperatures of up to 1430 °C. The microstructure was characterized and functionality was evaluated via hardness mapping. Nitrogen depletion adjacent to the fusion boundary depressed the upper temperature limit for austenite formation and influenced the phase balance above 980 °C. Austenite/ferrite boundaries deviating from Kurdjumov–Sachs orientation relationship (OR) were preferred locations for precipitation of σ at 630–1000 °C, χ at 560–1000 °C, Cr2N at 600–900 °C and R between 550 °C and 700 °C. Precipitate morphology changed with decreasing temperature; from blocky to coral-shaped for σ, from discrete blocky to elongated particles for χ, and from polygonal to disc-shaped for R. Thermodynamic calculations of phase equilibria largely agreed with observations above 750 °C when considering nitrogen loss. Formation of intermetallic phases and 475 °C-embrittlement resulted in increased hardness. A schematic diagram, correlating information about phase contents, morphologies and hardness, as a function of exposure temperature, is introduced for evaluation of functionality of microstructures.

  • 2.
    Abbadessa, Anna
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Oinonen, Petri
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Ecohelix AB, Teknikringen 38, SE-10044 Stockholm, Sweden..
    Henriksson, Gunnar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Characterization of Two Novel Bio-based Materials from Pulping Process Side Streams: Ecohelix and CleanFlow Black Lignin2018Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 13, nr 4, s. 7606-7627Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The characteristics of two novel types of technical lignin, namely Ecohelix (EH) and CleanFlow black lignin (CFBL), isolated from two different pulping process side streams, were analyzed. EH and CFBL were analyzed in terms of general composition, chemical functionalities, molar mass distribution, and thermal stability. For comparison, two relevant types of commercially available lignosulfonate and kraft lignin were used. The results showed that EH contains a large amount of sulfonated lignin, together with carbohydrates and ash. As such, it can be considered a lignin-carbohydrate hybrid molecule. CFBL was found to contain 91.5% Klason lignin and the lowest amount of carbohydrates (0.3%). EH showed the highest content of aliphatic OH groups (5.44 mmol/g) and CFBL a high content of phenols (4.73 mmol/g). EH had a molecular weight of 31.4 kDa and a sufficient thermal stability. CFBL had the lowest molecular weight (M-w = 2.0 kDa) and thermal stability of all kraft lignins analyzed in this study. These properties highlighted that EH is a suitable building block for material development and that CFBL is a promising material for the production of biofuel and biochemicals.

  • 3.
    Abbasi, M.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Backstrom, J.
    Mid Sweden Univ, FSCN Mat Phys, Dept Nat Sci, SE-85170 Sundsvall, Sweden..
    Cornell, Ann M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Fabrication of Spin-Coated Ti/TiHx/Ni-Sb-SnO2 Electrode: Stability and Electrocatalytic Activity2018Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 165, nr 9, s. H568-H574Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel three-layer anode having the composition Ti/TiHx/Ni-Sb-SnO2 (Ti/TiHx/NATO) was successfully prepared by a spin-coating and pyrolysis process aiming at a long service lifetime and good electrocatalytic properties for ozone formation. The TiHx as an interlayer was produced by electrochemical cathodic reduction of a coated layer of the TiOx on the titanium substrate. Spin coating and thermal decomposition were used to deposit the Sn-Sb-Ni precursor on the surface of the prepared Ti/TiHx electrode. Cyclic and linear scanning voltammetry, Raman spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to reveal the electrode performance and morphology. Results show that the onset potential for the oxygen evolution reaction (OER) of Ti/TiHx /NATO is higher than for Ti/NATO. They also indicate that the service lifetime of the Ti/TiHx/NATO is twice as long as the Ti/NATO at a current density of 50 mA.cm(-2) at room temperature. Electrochemical ozone generation and degradation of the methylene blue were investigated to confirm selectivity and activity of the electrodes. After 5 min electrolysis, a current efficiency for ozone generation of 56% was obtained the electrode with TiHx while 38% was obtained on Ti/NATO under same conditions. The results also confirm that the Ti/TiH x /NATO has a higher kinetic rate constant and decolorization efficiency for removal of the methylene blue compare to the Ti/NATO. The rate constant for the pseudo-first ordered reaction of methylene blue degradation showed high values of 350 x 10(-3) min(-1) for Ti/NATO and 440 x 10(-3) min(-1) for Ti/TiHx/NATO. 

  • 4.
    Abdel Alim, Richard
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Formation of Soft Particles in Drop-in Fuels2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    As the mission to the decrease global warming and phase out highly pollutingenvironmental practices globally, regulations including Euro 6 and policies generated by theUnited Nations Framework Convention on Climate Change (UNFCCC) are pushing companiesto be more innovative when it comes to their energy sources. These regulations involve manyfactors related to the cleanliness of the fuel and produced emissions, for example, propertiesof the fuels such as sulfur content, ash content, water content, and resulting emission valuesof Carbon dioxide (CO2) and Nitrogen Oxides (NOx). Furthermore, Sweden has set achallenging target of a fossil-fuel-independent vehicle fleet by 2030 and no net greenhousegasemissions by 2050.One way to cut down on the polluting properties in the fuel, as well as weakening thedependence on fossil fuel based fuel includes utilizing higher blending ratios of biofuels in thetransport sector. This transition to biofuels comes with many challenges to the transportindustry due to higher concentrations of these new fuels leads to clogging of the filters in theengine, as well as, internal diesel injector deposits (IDIDs) that produce injector fouling. Thisclogging of the filters leads to lower performance by the engines which leads to higher repairtimes (uptime) and less time on the road to transport goods. The formation of these softparticles at the root of the clogging issue is a pivotal issue because the precise mechanismsbehind their formation are highly unknown. Scania, a leader in the Swedish automotiveindustry, is very interested in figuring out what mechanisms are the most influential in theformation of these particles in the engine. Understanding the key mechanisms would allowScania to make appropriate adjustments to the fuel or the engines to ensure more time onthe road and less maintenance.There are many conditions known to be possible causes of the formation of softparticles in engines such as water content, ash content, and temperature. After generatingsoft particles using a modified accelerated method, particles were analyzed using infraredtechnology (RTX-FTIR) and a Scanning Electric Microscope (SEM-EDX). Many differentexperiments were performed to be able to make a conclusion as to which mechanisms weremost influential including temperature, time, water, air, and oil. The combination of agingbiofuels (B100, B10, HVO) with metals, and water produced the largest amount of particlesfollowed by aging the biofuels with aged oil, metals, and water. Aging the fuels with aged oilincreased particles, meanwhile the addition of water prevented particle production possiblydue to additives. B100 produced the highest amount of particles when aged with Copper, B10with Brass, and HVO with Iron.

  • 5.
    Abdel-Magied, Ahmed F.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Nasser Abdelhamid, Hani
    Ashour, Radwa M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Zou, Xiaodong
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Hierarchical porous zeolitic imidazolate framework nanoparticles for efficient adsorption of rare-earth elements2019Ingår i: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 278, s. 175-184Artikel i tidskrift (Refereegranskat)
  • 6.
    Abdi Yusuf Isse, Muna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Identifying Patient Safety and The Healthcare Environment in Puntland, Somalia2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Oberoende på var än i världen man befinner sig, anses patientsäkerhet vara en av de viktigaste aspekterna i sjukvården. Å andra sidan, helt beroende på var man befinner sig kommer patientsäkerheten skilja sig och är därför lägesberoende. Patientsäkerheten i ett utvecklingsland kommer därför uppfattas på ett annat sätt i jämförelse med ett I-land. Denna studie syftar till att identifiera patientsäkerheten i Puntland, Somalia och med det dess vårdmiljö i sjukhusen. Målet var att identifiera huvudfaktorerna som påverkar patientsäkerheten.

    För att undersöka detta utfördes en fältstudie i den valda regionen Puntland, därefter gjordes intervjuer med personal på plats i sjukhusen och dessutom utfördes observationer. De erhållna resultaten analyserades med hjälp av metoden “Qualitative Content Analysis”. Vid ett senare skede tematiseras resultaten till fyra kategorier; “​Behov​”, “​Apparat​”, “​Utbildning​” och “​Kunskap​”, vilka visade på de huvudsakliga problemen.

    Studien visade slutligen på att det fanns ett gemensamt genomgående problem av brist på apparater, utbildning och kunskap, vilket i sin tur skulle kunna påverka patienter och deras säkerhet på sätt såsom feldiagnoser, försenad behandling och i värsta fall döden. Vidare fastställdes att snarare än bristen på apparater, var avsaknaden av kunskap mer påtaglig. 

  • 7.
    Abdirahman Ahmed, Fatima
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Reologistudie av vattenbaserade industrifärger2018Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    I detta examensarbete har reologiska egenskaper av färg studerats varav viskoelasticitet, rinning och utflytning har varit av huvudsakligt intresse. I denna studie presenteras metoder som förutser hur färg rinner vid industriell applicering med hjälp av data från reologisk mätningsutrustning. Studiens övergripande syfte är att förstå hur vattenbaserad färg beter sig vid sprutning på vertikala ytor. Målet med studien har uppfyllts då det har kunnat visas att det går att förutse hur färg rinner med en påläggningsmängd på 300 μm i vått tillstånd.

    Med hjälp av en reometer kunde mätdata insamlas för att bestämma ett värde på en graderad skala. Fördelen med att använda en graderad skala istället är att det då går att undvika en kostsam och tidskrävande fysisk applicering av färgerna. Ett så kallat ”Shear rate loop test” användes för detta ändamål med hjälp av en grafisk tolkning. Den utvecklade metoden gav information som söktes om färgen rann eller ej.

    Varianter av oscillationstester som 3ITT, amplitudsvep och frekvenssvep används för att bestämma elastiska (G’) och viskösa (G’’) egenskaper, vilket kunde åskådliggöra vilket beteende som var dominerade hos färgerna. Studien har utgått från mätdata av 28 stycken olika färger. Studien har resulterat i två metoder som går att använda för att förutse rinning efter färgapplicering: Shear rate loop och 3ITT är metoderna.

  • 8.
    Abdirahman, Khalid
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Förnberg, Sebastian
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Styrsystem för solcellsladdade batterier2018Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Användandet av solceller ökar kontinuerligt i Sverige och effekten som genererasav solcellerna förvaras oftast i bly-syra batterier. Dessa batterier har en dåligpåverkan på miljön eftersom det krävs mycket energi och miljöfarliga material såsom bly och svavelsyra för att tillverka dessa batterier. Östersjökompaniet AB ochmånga av dess kunder inser vikten av ett hållbart tänkande och var intresseradeav att veta om det var möjligt att maximera livslängden av dessa batterier. Underarbetets gång analyserades olika metoder för upp- och urladdning av batterier somkan påverka ett batteris livslängd och hur man kan bära sig åt för att optimera det.En laddningskontroller användes för att optimera laddningen av batteriet. För attberäkna laddningsnivån i batteriet användes metoden ”Extended voltmeter”. Enprototyp som kunde ladda batterierna på ett optimalt sätt, varna då batterietsladdningsnivå blev för låg samt en användarvänlig applikation för övervakning avbatteriet konstruerades. Ett batteris beräknade livslängd är ingen exakt vetenskap.Enligt studier kan livslängden av ett batteri fördubblas om det laddas upp ochladdas ur på ett optimalt sätt i jämförelse med då det laddas ur helt.

  • 9.
    Abraham, Johannes
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Romano, Robin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Automatisk kvalitetssäkring av information för järnvägsanläggningar: Automatic quality assurance of information for railway infrastructure2019Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Järnvägsbranschen står i dagsläget inför stora utmaningar med planerade infrastrukturprojekt och underhåll av befintlig järnväg. Med ökade förväntningar på  utbyggnaden av den framtida järnvägen, medför det en ökad risk för belastning på det nuvarande nätet. Baksidan av utbyggnaden kan bli fler inställda resor och  förseningar. Genom att dra nytta av tekniska innovationer såsom digitalisering och  automatisering kan det befintliga system och arbetsprocesser utvecklas för en  effektivare hantering.  Trafikverket ställer krav på Byggnadsinformationsmodeller (BIM) i upphandlingar. Projektering för signalanläggningar sker hos Sweco med CAD-programmet  Promis.e. Från programmet kan Baninformationslistor (BIS-listor) innehållande  information om objekts attribut hämtas. Trafikverket ställer krav på att attributen ska bestå av ett visst format eller ha specifika värden. I detta examensarbete  undersöks metoder för att automatisk verifiera ifall objekt har tillåtna värden från projekteringsverktyget samt implementering av en metod. Undersökta metoder  innefattar kalkyleringsprogrammet Excel, frågespråket Structured Query Language (SQL) och processen Extract, Transform and Load (ETL).  Efter analys av metoder valdes processen ETL. Resultatet blev att ett program  skapades för att automatiskt välja vilken typ av BIS-lista som skulle granskas och för att verifiera om attributen innehöll tillåtna värden. För att undersöka om kostnaden för programmen skulle gynna företaget utöver kvalitetssäkringen utfördes en  ekonomisk analys. Enligt beräkningarna kunde valet av att automatisera  granskningen även motiveras ur ett ekonomiskt perspektiv.

  • 10. Abtahi, Farhad
    et al.
    Forsman, Mikael
    Diaz-Olivazrez, Jose A.
    KTH, Skolan för teknik och hälsa (STH).
    Yang, Liyun
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Ergonomi.
    Lu, Ke
    KTH, Skolan för teknik och hälsa (STH).
    Eklund, Jörgen
    KTH, Skolan för teknik och hälsa (STH).
    Lindecrantz, Kaj
    KTH, Skolan för teknik och hälsa (STH).
    Seoane, Fernando
    Teriö, Heikki
    Mediavilla Martinez, Cesar
    Aso, Santiago
    Tiemann, Christian
    Big Data & Wearable Sensors Ensuring Safety and Health @Work2017Ingår i: GLOBAL HEALTH 2017, The Sixth International Conference on Global Health Challenges, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    —Work-related injuries and disorders constitute a major burden and cost for employers, society in general and workers in particular. We@Work is a project that aims to develop an integrated solution for promoting and supporting a safe and healthy working life by combining wearable technologies, Big Data analytics, ergonomics, and information and communication technologies. The We@Work solution aims to support the worker and employer to ensure a healthy working life through pervasive monitoring for early warnings, prompt detection of capacity-loss and accurate risk assessments at workplace as well as self-management of a healthy working life. A multiservice platform will allow unobtrusive data collection at workplaces. Big Data analytics will provide real-time information useful to prevent work injuries and support healthy working life

  • 11.
    Acevedo Gomez, Yasna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    On Gas Contaminants, and Bipolar Plates in Proton Exchange Membrane Fuel Cells2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Polymerelektrolytbränslecellen är en elektrokemisk enhet som omvandlar den kemiskt bundna energin i ett bränsle till elektrisk energi genom två elektrokatalytiska reaktioner. Den vanligaste katalysatorn som används är Pt/C som hittills också har visat bäst prestanda i bränslecellen. Nackdelen med denna katalysator är dock att den inte tolererar föroreningar. Både vätgas och syrgas kan innehålla små mängder av föroreningar beroende på ursprung. Syftet med denna avhandling är att förstå effekten på cellens prestanda av två olika föroreningar som är mindre undersökta: Ammoniak som kan medfölja vid reformering av förnybara råvaror till vätgas, och kvävedioxid som kan komma från luftföroreningar. Mekanismer för förorening av cellen och en adekvat återhämtningsmetod för respektive förorening har studerats. Dessutom, bipolära plattor av rostfritt stål elektrokemiskt belagda med Ni-Mo eller Ni-Mo-P, undersökts som ett alternativ till rent rostfritt stål- och grafit.

    Resultaten visar att ammoniak inte bara åstadkommer förändringar i polymermembranet utan också i syrereduktionsreaktionen (ORR), väteoxidationsreaktionen (HOR) och jonomeren i de båda elektroderna. Till vilken grad som försämrad prestanda efter förorening kan återhämtas, beror både på koncentrationen av ammoniak och exponeringstid. När det gäller kvävedioxid så påverkar en bara elektrodens katalysator där försämringen av elektroden är relaterad till sidoreaktioner som sker på katalysatorytan. NO2 är dock inte starkt bunden till katalysatorn och det är möjligt att återhämta prestandan med bara ren luft. Tiden som återhämtningsprocessen tar beror på cellpotentialen och luftflödet.

    Utvärderingen av elektropläterade skikt av Ni-Mo och Ni-Mo-P på rostfritt stål, som gjorts genom mätningar ex-situ och in-situ, visar att dessa beläggningar avsevärt minskar det interna kontaktmotståndet (ICR) och korrosionen av rostfritt stål. In-situ-experimenten visar att tillsatsen av  fosfor i beläggningen inte förbättrar bränslecellens prestanda, men att legering av Ni-Mo är ett lovande material att använda vid elektroplätering av skyddande skikt på bipolära plattor av rostfritt stål.

  • 12.
    Acevedo Gomez, Yasna
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lagergren, Carina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Effect of nitrogen dioxide impurities on PEM fuel cell performanceManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Air is the most practical and economical oxidant to feed to the cathode in a proton exchange membrane fuel cell (PEMFC). However, the air is accompanied by small amounts of impurities that affect the performance of the fuel cell. Among these, nitrogen dioxide is the impurity that has been least investigated, and its effect is not fully understood. In this study, a possible mechanism is proposed based on the contamination of the fuel cell at different concentrations and adsorption potentials, and by employing stripping cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The results at different concentrations showed that the catalyst sites are blocked by the adsorption of NO2, and that there is a non-linear relationship between the concentration and degradation. The degradation is suggested to be related to the formation of intermediate species, as also shown by the pseudo-inductive impedance at the concentration of 100 and 200 ppm. Furthermore, the cyclic voltammetry showed that there is an oxidation to NO3- at 1.05 V, followed by the reduction of this specie to NO2- at 0.68 V, and a subsequent reduction of NO2- to N2O and/or NH2OH.

  • 13.
    Acevedo Gomez, Yasna
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lagergren, Carina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Performance recovery after contamination with nitrogen dioxide in a PEM fuel cellManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    While the market of fuel cell vehicles is increasing, these vehicles will still coexist with combustion engine vehicles on the roads and will be exposed to an environment with significant amounts of contaminants that will decrease the durability of the fuel cell. In order to investigate different recovery methods, a PEM fuel cell is in this study contaminated with 100 ppm of NO2 at the cathode side. The possibility to recover the cell performance is studied by using different airflow rates, different current densities, and by subjecting the cell to successive polarization curves. The results show that the successive polarization curves are the best choice for recovery; it took 35 min to reach full recovery of cell performance, compared to 4.5 hours of recovery with pure air at 0.5 A cm-2 and 110 ml min-1. However, the performance recovery at a current density of 0.2 A cm-2 and air flow 275 ml min-1 was done in 66 min, which is also a possible alternative. Additionally, two operation techniques are suggested and compared during 7 h of operation; air recovery and air depletion. The air recovery technique shows to be a better choice than the air depletion technique.

  • 14. Addicoat, Matthew
    et al.
    Atkin, Rob
    Canongia Lopes, José Nuno
    Costa Gomes, Margarida
    Firestone, Millicent
    Gardas, Ramesh
    Halstead, Simon
    Hardacre, Christopher
    Hardwick, Laurence J.
    Holbrey, John
    Hunt, Patricia
    Ivaništšev, Vladislav
    Jacquemin, Johan
    Jones, Robert
    Kirchner, Barbara
    Lynden-Bell, Ruth
    MacFarlane, Doug
    Marlair, Guy
    Medhi, Himani
    Mezger, Markus
    Pádua, Agílio
    Pantenburg, Isabel
    Perkin, Susan
    Reid, Joshua E. S. J.
    Rutland, Mark W.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Saha, Satyen
    Shimizu, Karina
    Slattery, John M.
    Swadźba-Kwaśny, Malgorzata
    Tiwari, Shraeddha
    Tsuzuki, Seiji
    Uralcan, Betul
    van den Bruinhorst, Adriaan
    Watanabe, Masayoshi
    Wishart, James
    Structure and dynamics of ionic liquids: general discussion2018Ingår i: Faraday discussions (Online), ISSN 1359-6640, E-ISSN 1364-5498, Vol. 206, nr 0, s. 291-337Artikel i tidskrift (Refereegranskat)
  • 15.
    Adolfsson, Karin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Carbon flake coated cellulose filters as dual function devices for rapid environmental contaminant detectionManuskript (preprint) (Övrigt vetenskapligt)
  • 16.
    Adolfsson, Karin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hydrothermal recycling of natural and synthetic polymers to functional carbon materials2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Utilizing renewable recourses and waste recycling are necessary for reaching a circular resource society. The concept of this thesis was to set up a sustainable recycling route, suitable even for low quality biopolymer and plastic waste for production of functional carbon materials. Carbonaceous materials were prepared by mild hydrothermal carbonizations of cellulose and polypropylene (PP) under acidic conditions. The carbonization of cellulose resulted mainly in micro-/nanometer sized carbon spheres (CS) with polar functionalities. After carbonization of PP, products were found in solid and liquid phase. Completely carbonized solid carbons products were obtained from PP at 250 °C after 60 min. The liquid products from the same process displayed aromatics and exhibited fluorescence properties. In addition, new carbon materials were prepared by acid, base and thermal treatments of the carbonized products at low temperatures. Thermally resistant carbon products and antibacterial CS towards both Staphylococcus aureus and Pseudomonas aeruginosa were demonstrated as possible applications for these products. The minimum inhibitory concentrations of CS were 200-400 µg mL-1 depending on the bacteria strain and reached after only 3 h. Furthermore, nanometer sized carbon nanodots with high oxygenation degree and fluorescence properties were derived together with carbon flakes (CF) from the carbonized products. The CF with flat and micrometer sized morphology and polar groups were utilized for coating of cationized cellulose filters, applied as adsorbents and then subsequently as surfaces for SALDI-MS analysis of environmental contaminants. This work contributes with new routes to and applications for functional carbon materials.

    Publikationen är tillgänglig i fulltext från 2020-04-30 10:30
  • 17.
    Adolfsson, Karin H.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Golda-Cepa, M
    Benyahia Erdal, Nejla
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Duch, J
    Kotarba, A
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Importance of Surface Functionalities for Antibacterial Properties of Carbon Spheres2019Ingår i: Advanced Sustainable Systems, ISSN 2366-7486Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Carbon spheres (CS) are interesting materials for antibacterial applications. Herein, CS are produced by a green process utilizing microwave-assisted hydrothermal treatment of cellulose. The CS are then postmodified in acidic and basic solutions to evaluate the influence of different functionalities on antibacterial properties. CS contain OH/COOH, C Symbol of the Klingon Empire C, and C Symbol of the Klingon Empire O functionalities, while O-CS produced by acid treatment of CS have additional COOH, and NH/NH2 groups, resulting in carbon spheres with negatively and positively charged groups in dispersion. Treatment with base (Na-CS) removes low molecular weight species with oxygen and results in carbon spheres with the highest C/O ratio. CS, O-CS, and Na-CS have nonporous morphology and are in micro/nanometer sizes, although, smaller sized spheres, hollow spheres, and fragments are also attained in the case of O-CS. O-CS show antibacterial activity toward both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Pseudomonas aeruginosa (P. aeruginosa). The minimum inhibitory concentration is 200 and 400 mu g mL(-1) for S. aureus and P. aeruginosa, respectively, and is achieved only after 3 h of incubation. Neither CS nor Na-CS exhibit antibacterial activity. The antibacterial activity is suggested to originate from electrostatic interactions between O-CS and the bacteria.

  • 18.
    Adolfsson, Karin H.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Golda-Cepa, Monika
    Jagiellonian Univ, Fac Chem, Ul Gronostajowa 2, PL-30387 Krakow, Poland..
    Benyahia Erdal, Nejla
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Duch, Joanna
    Jagiellonian Univ, Fac Chem, Ul Gronostajowa 2, PL-30387 Krakow, Poland..
    Kotarba, Andrzej
    Jagiellonian Univ, Fac Chem, Ul Gronostajowa 2, PL-30387 Krakow, Poland..
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Importance of Surface Functionalities for Antibacterial Properties of Carbon Spheres2019Ingår i: ADVANCED SUSTAINABLE SYSTEMS, ISSN 2366-7486, Vol. 3, nr 4, artikel-id 1800148Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Carbon spheres (CS) are interesting materials for antibacterial applications. Herein, CS are produced by a green process utilizing microwave-assisted hydrothermal treatment of cellulose. The CS are then postmodified in acidic and basic solutions to evaluate the influence of different functionalities on antibacterial properties. CS contain OH/COOH, C Symbol of the Klingon Empire C, and C Symbol of the Klingon Empire O functionalities, while O-CS produced by acid treatment of CS have additional COOH, and NH/NH2 groups, resulting in carbon spheres with negatively and positively charged groups in dispersion. Treatment with base (Na-CS) removes low molecular weight species with oxygen and results in carbon spheres with the highest C/O ratio. CS, O-CS, and Na-CS have nonporous morphology and are in micro/nanometer sizes, although, smaller sized spheres, hollow spheres, and fragments are also attained in the case of O-CS. O-CS show antibacterial activity toward both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Pseudomonas aeruginosa (P. aeruginosa). The minimum inhibitory concentration is 200 and 400 mu g mL(-1) for S. aureus and P. aeruginosa, respectively, and is achieved only after 3 h of incubation. Neither CS nor Na-CS exhibit antibacterial activity. The antibacterial activity is suggested to originate from electrostatic interactions between O-CS and the bacteria.

  • 19.
    Adolfsson, Karin H.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lin, Chia-feng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Microwave Assisted Hydrothermal Carbonization and Solid State Postmodification of Carbonized Polypropylene2018Ingår i: ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN 2168-0485, Vol. 6, nr 8, s. 11105-11114Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Functional carbon materials produced through a hydrothermal treatment of waste products have gained interest. Particularly, the method is considered more facile and green compared to conventional decomposition methods. Here, we demonstrated an upcycling of polypropylene (PP) waste to carbon materials by a microwave assisted hydro thermal treatment. The solid product obtained from the hydrothermal treatment was analyzed by multiple techniques to reveal the structure and the influence of processing conditions on PP degradation and hydrothermal carbonization. Chemical analyses showed the presence of carbonaceous material independent of acid amount (20 and 30 mL), temperature (210 and 250 degrees C), and time (20-80 min). A complete transformation of PP content to amorphous carbon required 60 min at 250 degrees C. The mass yield of the solid product decreased as a function of harsher processing conditions. At the same time, thermogravimetric analysis illustrated products with increasing thermal stability and a larger amount of remaining residue at 600 degrees C. The solid products consisted of irregular fragments and sheet-like structures. A solid state microwave process in air atmosphere was performed on a product with incomplete carbonization. The modification resulted in a decreased C/O ratio, and TGA analysis in nitrogen showed high thermal stability and degree of carbonization as indicated by the remaining residue of 86.4% at 600 degrees C. The new insights provided on the hydrothermal carbonization, and postmodification in air atmosphere, can catalyze effective handling of plastic waste by enabling transformation of low quality waste into functional carbon materials.

  • 20.
    Agerskov, Niels
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Adaptable Semi-Automated 3D Segmentation Using Deep Learning with Spatial Slice Propagation2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Trots att framstegen inom djupinlärning banar vägen för medicinsk bildanalys snabbare än någonsin så finns det ett stort problem, mängden annoterad bilddata. Det har bland annat att göra med att medicinsk bilddata tar väldigt lång tid att annotera manuellt. I detta projektet har en semi-automatisk algoritm utvecklats som tar sig an 3D-segmentering från ett 2D-perspektiv. En bildvolym segmenteras genom att en initialiseringbild annoteras manuellt och används som hjälp för att annotera närliggande bilder i volymen. Detta upprepas sedan för resterande bilder men istället för att manuellt annotera används föregående segmentering av närverket som hjälp. Detta tillåter att algoritmen både kan generalisera till helt nya fall som ej är representerade av träningsdatan, och gör även att felaktigt segmenterade bilder kan korrigeras i efterhand. Korrigeringar kommer då att propageras genom volymen genom att varje segmentering används som hjälp för nästkommande bild. Resultaten är i nivå med motsvarande helautomatiska algoritmer inom träningsdomänen. Den största fördelen gentemot dessa är möjligheten att segmentera helt nya fall. Metoden som används för att träna nätverket att förlita sig på hjälpbilder bygger på kraftig bilddistortion av bilden som ska segmenteras. Detta tvingar nätverket att ta vara på informationen i segmenteringen av föregående bild.

  • 21.
    Aguilera Costa, Joakim
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Uppgradering och identifiering av cellulosa och hemicellulosa i restströmmar från jordbruk och skogsindustri2018Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Restprodukter är i fokus för vidareförädling. Restprodukter från jordbruk och skogsindustri innehåller en stor mängd fibrer och detta arbete undersöker restprodukternas kvalitativa egenskaper samt om det finns potential för att använda dem i cellulosaindustrin.

    Restprodukter som samlades in var vetehalm, rapshalm, vetekli, betfor, ensilage, grot, primärslam, sågspån samt fiberrejekt. En litteraturstudie utfördes om varje restprodukt för att få en bättre förståelse av vad de består av och hur de uppstår.

    Genom att extrahera holocellulosa från restprodukterna analyserades de kvalitativa egenskaperna som fibrerna har. För minsta möjliga förändring av fibrernas form och dimensioner användes en macereringsmetod för att extrahera holocellulosa från restmaterialen.

    Metoder som användes för att analysera de kvalitativa egenskaperna hos restprodukterna var viskositets bestämning, titreringar och gravimetriska analyser. Med dessa metoder kunde massutbyten, askhalter, massviskositeter, perättiksyra- och väteperoxidhalter avgöras för de extraherade holocellulosamassorna.

    För att undersöka om de extraherade holocellulosamassorna kan användas i cellulosaindustrin testades två typer av processer. Den ena var aerogelproduktionen och den andra en kompressionsgjutning för produktionen av biokompositer med hög styrka.

    Det visade sig att fiberrejekt gav störst holocellulosautbyte jämfört med de andra restprodukterna. Analyserna gav resultatet att sågspån hade de fibrer med högst polymerisationsgrad medan vetekli och betfor hade de fibrer med lägst polymersiationsgrad. Upplösningen av holocellulosamassans fibrer gick inte att utföra då testprovet hade antingen för hög massviskositet eller för hög andel hemicellulosa som förhindrar att lösningsmedlet löser upp fibrerna. Kompressionsgjutning av holocellulosamassan från vetehalm var lyckat då det gick att förädla den mjuka massan till en massa med mer styvhet. Kompressionsgjutning av holocellulosamassorna kan vara ett alternativ för att producera material för additiv tillverkning (3D-printing).

  • 22.
    Ahlinder, Astrid
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Fuoco, Tiziana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Finne Wistrand, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Medical grade polylactide, copolyesters and polydioxanone: Rheological properties and melt stability2018Ingår i: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 72, s. 214-222Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Rheological measurements have shown that lactide-based copolymers with L-lactide content between 50 and 100 mol% with varying comonomers, as well as polydioxanone (PDX), can be used in additive manufacturing analogously to poly(L-lactide) (PLLA) if their melt behaviour are balanced. The results indicate that copolymers can be melt processed if the temperature is adjusted according to the melting point, and parameters such as the speed are tuned to conteract the elastic response. Small amplitude oscillatory shear (SAOS) rheology, thermal and chemical characterisation allowed us to map the combined effect of temperature and frequency on the behaviour of six degradable polymers and their melt stability. Values of complex viscosity and Tan delta obtained through nine time sweeps by varying temperature and frequency showed that the molecular structure and the number of methylene units influenced the results, copolymers of L-lactide with D-Lactide (PDLLA) or glycolide (PLGA) had an increased elastic response, while copolymers with trimethylene carbonate (PLATMC) or epsilon-caprolactone (PCLA) had a more viscous behaviour than PLLA, with respect to their relative melting points. PDLLA and PLGA require an increased temperature or lower speed when processed, while PLATMC and PCLA can be used at a lower temperature and/or higher speed than PLLA. PDX showed an increased viscosity compared to PLLA but a similar melt behaviour. Negligible chain degradation were observed, apart from PLGA.

  • 23.
    Ahlquist, Mårten S. G.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi.
    Marcos-Escartin, Rocio
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi.
    Bicarbonate hydrogenation by iron: Effects of solvent and ligand on the mechanism2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Artikel i tidskrift (Övrigt vetenskapligt)
  • 24.
    Ahlquist, Mårten
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi.
    Zhan, Shaoqi
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi.
    Modeling molecular water oxidation catalysts at interfaces2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Artikel i tidskrift (Övrigt vetenskapligt)
  • 25.
    Ahluwalia, A.
    et al.
    Italy.
    De Maria, C.
    Italy.
    Lantada, A. D.
    Spain.
    Pietro, L. D.
    Italy.
    Ravizza, A.
    Italy.
    Mridha, Mannan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Madete, J.
    Kenya.
    Makobore, P. N.
    Uganda.
    Aabloo, A.
    Estonia.
    Kitsing, R.
    Estonia.
    Leivobits, A.
    Estonia.
    Towards open source medical devices current situation, inspiring advances and challenges2018Ingår i: BIODEVICES 2018 - 11th International Conference on Biomedical Electronics and Devices, Proceedings; Part of 11th International Joint Conference on Biomedical Engineering Systems and Technologies, BIOSTEC 2018, SciTePress, 2018, s. 141-149Konferensbidrag (Refereegranskat)
    Abstract [en]

    Open Source Medical Devices may be part of the solution towards the democratization of medical technologies pursuing Universal Health Coverage as part of the Sustainable Development Goals for United Nations. Recent technological advances, especially in information and communication technologies, combined with innovative collaborative design methodologies and manufacturing techniques allow for the mass-personalization of biodevices and help to optimize the related development times and costs, while keeping safety in the foreground through the whole life cycle of medical products. These advantages can be further promoted by adequately fostering collaboration, communication, high value information exchange, and sustainable partnerships and by extending the employment of open source strategies. To this end, within the UBORA project, we are developing a framework for training the biomedical engineers of the future in open-source collaborative design strategies and for supporting the sharing of information and the assessment of safety and efficacy in novel biodevices. An essential part of this open-source collaborative framework is the UBORA e-infrastructure, which is presented in this study, together with some initial success cases. Main future challenges, connected with regulatory harmonization, with educational issues and with accessible and open design and manufacturing resources, among others, are also presented and discussed.

  • 26.
    Ahluwalia, Arti
    et al.
    Univ Pisa, Dept Ingn Informaz, Bioengn, Pisa, Italy..
    De Maria, Carmelo
    Univ Pisa, Dept Ingn Informaz, Bioengn, Pisa, Italy..
    Diaz Lantada, Andres
    UPM, ETSII, Dept Mech Engn, Madrid, Spain..
    Madete, June
    Univ Pisa, Res Ctr E Piaggio, Pisa, Italy.;Kenyatta Univ, Nairobi, Kenya..
    Makobore, Philippa Ngaju
    Uganda Ind Res Inst, Instrumentat Div, Kampala, Uganda..
    Ravizza, Alice
    Univ Pisa, Pisa, Italy..
    Di Pietro, Licia
    Mridha, Mannan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Munoz-Guijosa, Juan Manuel
    UPM, ETSII, Dept Mech Engn, Madrid, Spain..
    Tanarro, Enrique Chacon
    UPM, ETSII, Dept Mech Engn, Madrid, Spain..
    Torop, Janno
    Tartu Ulikool, Inst Technol, Tartu, Estonia..
    Biomedical Engineering Project Based Learning: Euro-African Design School Focused on Medical Devices2018Ingår i: International Journal of Engineering ,Science and Innovative Technology, ISSN 0949-149X, E-ISSN 2277-3754, Vol. 34, nr 5, s. 1709-1722Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biomedical engineering (BME) has the potential of transforming medical care towards universal healthcare by means of the democratization of medical technology. To this end, innovative holistic approaches and multidisciplinary teams, built upon the gathering of international talent, should be encouraged within the medical industry. However, these transformations can only be accomplished if BME education also continuously evolves and focuses on the internationalization of students, the promotion of collaborative design strategies and the orientation towards context relevant medical needs. In this study we describe an international teaching-learning experience, the "UBORA (Swahili for 'excellence') Design School". During an intensive week of training and collaboration 39 engineering students lived through the complete development process for creating innovative open-source medical devices following the CDIO ("conceivedesign-implement-operate") approach and using the UBORA e-infrastructure as a co-design platform. Our post-school survey and analyses showed that this integral teaching-learning experience helped to promote professional skills and could nurture the future generation of biomedical engineers, who could transform healthcare technology through collaborative design oriented to open source medical devices.

  • 27.
    Ahmad, Shargeel
    et al.
    Dalian Univ Technol, Inst Artificial Photosynthesis, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Liu, Jinxuan
    Dalian Univ Technol, Inst Artificial Photosynthesis, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Ji, Wei
    Dalian Univ Technol, Inst Artificial Photosynthesis, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi. Dalian Univ Technol, Inst Artificial Photosynthesis, State Key Lab Fine Chem, Dalian 116024, Peoples R China.;KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Chem, S-10044 Stockholm, Sweden..
    Metal-Organic Framework Thin Film-Based Dye Sensitized Solar Cells with Enhanced Photocurrent2018Ingår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 11, nr 10, artikel-id 1868Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Metal-organic framework thin film-based dye sensitized solar cell is fabricated with highly oriented, crystalline, and porous Zn-perylene metal-organic framework (MOF) thin film (SURMOF) which is integrated with Bodipy embedded in poly(methyl methacrylate). It has been demonstrated that the photocurrent can be enhanced by a factor of 5 relative to Zn-perylene MOF thin film due to triplet-triplet annihilation up-conversion between the Bodipy/PMMA sensitizer and the Zn-perylene MOF thin film acceptor using Co(bpy)(3)(2+/3+) as redox mediator.

  • 28. Ahmed, Mona
    et al.
    Baumgartner, Roland
    Aldi, Silvia
    Dusart, Philip
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Cellulär och klinisk proteomik.
    Hedin, Ulf
    Gustafsson, Bjorn
    Caidahl, Kenneth
    Human serum albumin-based probes for molecular targeting of macrophage scavenger receptors2019Ingår i: International Journal of Nanomedicine, ISSN 1176-9114, E-ISSN 1178-2013, Vol. 14, s. 3723-3741Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Inflammation and accumulation of macrophages are key features of unstable atherosclerotic plaques. The ability of macrophages to take up molecular probes can be exploited in new clinical imaging methods for the detection of unstable atherosclerotic lesions. We investigated whether modifications of human serum albumin (HSA) could be used to target macrophages efficiently in vitro. Materials and methods: Maleylated and aconitylated HSA were compared with unmodified HSA. Fluorescent or radiolabeled (Zr-89) modified HSA was used in in vitro experiments to study cellular uptake by differentiated THP-1 cells and primary human macrophages. The time course of uptake was evaluated by flow cytometry, confocal microscopy, real-time microscopy and radioactivity measurements. The involvement of scavenger receptors (SR-Al, SR-B2, LOX-1) was assessed by knockdown experiments using RNA interference, by blocking experiments and by assays of competition by modified low-density lipoprotein. Results: Modified HSA was readily taken up by different macrophages. Uptake was mediated nonexclusively via the scavenger receptor SR-Al (encoded by the MSR1 gene). Knockdown of CD36 and ORL1 had no influence on the uptake. Modified HSA was preferentially taken up by human macrophages compared with other vascular cell types such as endothelial cells and smooth muscle cells. Conclusions: Modified Zr-89-labeled HSA probes were recognized by different subsets of polarized macrophages, and maleylated HSA may be a promising radiotracer for radio-nuclide imaging of macrophage-rich inflammatory vascular diseases.

  • 29.
    Ahmed, Mona
    et al.
    Karolinska Inst, Dept Mol Med & Surg, Ctr Mol Med, S-17176 Stockholm, Sweden..
    Gustafsson, Björn
    Karolinska Inst, Dept Mol Med & Surg, Ctr Mol Med, S-17176 Stockholm, Sweden..
    Aldi, Silvia
    Karolinska Inst, Sect Med Inflammat Res, Dept Med Biochem & Biophys, S-17177 Stockholm, Sweden..
    Dusart, Philip
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Cellulär och klinisk proteomik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Egri, Gabriella
    Surflay Nanotec GmbH, Max Planck Str 3, D-12489 Berlin, Germany..
    Butler, Lynn M.
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Cellulär och klinisk proteomik.
    Bone, Dianna
    Karolinska Inst, Dept Mol Med & Surg, Ctr Mol Med, S-17176 Stockholm, Sweden..
    Dahne, Lars
    Surflay Nanotec GmbH, Max Planck Str 3, D-12489 Berlin, Germany..
    Hedin, Ulf
    Karolinska Inst, Dept Mol Med & Surg, Ctr Mol Med, S-17176 Stockholm, Sweden..
    Caidahl, Kenneth
    Karolinska Inst, Dept Mol Med & Surg, Ctr Mol Med, S-17176 Stockholm, Sweden.;Univ Gothenburg, Sahlgrenska Acad, Inst Med, Dept Mol & Clin Med, S-41345 Gothenburg, Sweden..
    Molecular Imaging of a New Multimodal Microbubble for Adhesion Molecule Targeting2019Ingår i: Cellular and Molecular Bioengineering, ISSN 1865-5025, E-ISSN 1865-5033, Vol. 12, nr 1, s. 15-32Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Introduction: Inflammation is an important risk-associated component of many diseases and can be diagnosed by molecular imaging of specific molecules. The aim of this study was to evaluate the possibility of targeting adhesion molecules on inflammation-activated endothelial cells and macrophages using an innovative multimodal polyvinyl alcohol-based microbubble (MB) contrast agent developed for diagnostic use in ultrasound, magnetic resonance, and nuclear imaging. Methods: We assessed the binding efficiency of antibody-conjugated multimodal contrast to inflamed murine or human endothelial cells (ECs), and to peritoneal macrophages isolated from rats with peritonitis, utilizing the fluorescence characteristics of the MBs. Single-photon emission tomography (SPECT) was used to illustrate 99m Tc-labeled MB targeting and distribution in an experimental in vivo model of inflammation. Results: Flow cytometry and confocal microscopy showed that binding of antibody-targeted MBs to the adhesion molecules ICAM-1, VCAM-1, or E-selectin, expressed on cytokine-stimulated ECs, was up to sixfold higher for human and 12-fold higher for mouse ECs, compared with that of non-targeted MBs. Under flow conditions, both VCAM-1- and E-selectin-targeted MBs adhered more firmly to stimulated human ECs than to untreated cells, while VCAM-1-targeted MBs adhered best to stimulated murine ECs. SPECT imaging showed an approximate doubling of signal intensity from the abdomen of rats with peritonitis, compared with healthy controls, after injection of anti-ICAM-1-MBs. Conclusions: This novel multilayer contrast agent can specifically target adhesion molecules expressed as a result of inflammatory stimuli in vitro, and has potential for use in disease-specific multimodal diagnostics in vivo using antibodies against targets of interest.

  • 30.
    Ahuja, Dipali
    et al.
    Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Castletroy, Co Limerick, Ireland..
    Svärd, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Teknisk strömningslära. Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Castletroy, Co Limerick, Ireland..
    Rasmuson, Åke C.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Teknisk strömningslära. Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Castletroy, Co Limerick, Ireland..
    Investigation of solid-liquid phase diagrams of the sulfamethazine-salicylic acid co-crystal2019Ingår i: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 21, nr 18, s. 2863-2874Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of temperature and solvent on the solid-liquid phase diagram of the 1 : 1 sulfamethazinesalicylic acid co-crystal has been investigated. Ternary phase diagrams of this co-crystal system have been constructed in three solvents: methanol, acetonitrile and a 7 : 3 (v/v) dimethylsulfoxide-methanol mixture, at three temperatures. The system exhibits congruent dissolution in acetonitrile and the co-crystal solubility has been determined by a gravimetric technique. The Gibbs energy of co-crystal formation from the respective solid components has been estimated from solubility data, together with the corresponding enthalpic and entropic component terms. The Gibbs energy of formation ranges from -5.7 to -7.7 kJ mol -1, with the stability increasing with temperature. In methanol and the DMSO-methanol mixture, the co-crystal dissolves incongruently. It is shown that the solubility ratio of the pure components cannot be used to predict with confidence whether the co-crystal will dissolve congruently or incongruently. The size of the region where the co-crystal is the only stable solid phase is inversely related to the pure component solubility ratio of salicylic acid and sulfamethazine.

  • 31.
    Akhter, Shirin
    et al.
    Swedish Univ Agr Sci, Linnean Ctr Plant Biol, Uppsala Bioctr, Dept Plant Biol, Uppsala, Sweden..
    Kretzschmar, Warren W.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH Royal Inst Technol, Sch Engn Sci Biotechnol Chem & Hlth, Dept Gene Technol, Sci Life Lab, Solna, Sweden..
    Nordal, Veronika
    Swedish Univ Agr Sci, Linnean Ctr Plant Biol, Uppsala Bioctr, Dept Plant Biol, Uppsala, Sweden..
    Delhomme, Nicolas
    Swedish Univ Agr Sci, Dept Forest Genet & Plant Physiol, Umea Plant Sci Ctr, Umea, Sweden..
    Street, Nathaniel R.
    Umea Sweden, Dept Plant Physiol, Umea Plant Sci Ctr, Umea, Sweden..
    Nilsson, Ove
    Swedish Univ Agr Sci, Dept Forest Genet & Plant Physiol, Umea Plant Sci Ctr, Umea, Sweden..
    Emanuelsson, Olof
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Sundström, Jens F.
    Swedish Univ Agr Sci, Linnean Ctr Plant Biol, Uppsala Bioctr, Dept Plant Biol, Uppsala, Sweden..
    Integrative Analysis of Three RNA Sequencing Methods Identifies Mutually Exclusive Exons of MADS-Box Isoforms During Early Bud Development in Picea abies2018Ingår i: Frontiers in Plant Science, ISSN 1664-462X, E-ISSN 1664-462X, Vol. 9, artikel-id 1625Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recent efforts to sequence the genomes and transcriptomes of several gymnosperm species have revealed an increased complexity in certain gene families in gymnosperms as compared to angiosperms. One example of this is the gymnosperm sister Glade to angiosperm TM3-like MADS-box genes, which at least in the conifer lineage has expanded in number of genes. We have previously identified a member of this subclade, the conifer gene DEFICIENS AGAMOUS LIKE 19 (DAL19), as being specifically upregulated in cone-setting shoots. Here, we show through Sanger sequencing of mRNA-derived cDNA and mapping to assembled conifer genomic sequences that DAL19 produces six mature mRNA splice variants in Picea abies. These splice variants use alternate first and last exons, while their four central exons constitute a core region present in all six transcripts. Thus, they are likely to be transcript isoforms. Quantitative Real-Time PCR revealed that two mutually exclusive first DAL19 exons are differentially expressed across meristems that will form either male or female cones, or vegetative shoots. Furthermore, mRNA in situ hybridization revealed that two mutually exclusive last DAL19 exons were expressed in a cell-specific pattern within bud meristems. Based on these findings in DAL19, we developed a sensitive approach to transcript isoform assembly from short-read sequencing of mRNA. We applied this method to 42 putative MADS-box core regions in P abies, from which we assembled 1084 putative transcripts. We manually curated these transcripts to arrive at 933 assembled transcript isoforms of 38 putative MADS-box genes. 152 of these isoforms, which we assign to 28 putative MADS-box genes, were differentially expressed across eight female, male, and vegetative buds. We further provide evidence of the expression of 16 out of the 38 putative MADS-box genes by mapping PacBio Iso-Seq circular consensus reads derived from pooled sample sequencing to assembled transcripts. In summary, our analyses reveal the use of mutually exclusive exons of MADS-box gene isoforms during early bud development in P. abies, and we find that the large number of identified MADS-box transcripts in P. abies results not only from expansion of the gene family through gene duplication events but also from the generation of numerous splice variants.

  • 32.
    Alander, B.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Capezza, A.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material. Department of Plant Breeding, The Swedish University of Agricultural Sciences, Box 101, Alnarp, Sweden.
    Wu, Q.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Johansson, E.
    Olsson, Richard T.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Hedenqvist, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    A facile way of making inexpensive rigid and soft protein biofoams with rapid liquid absorption2018Ingår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 119, s. 41-48Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel and facile method to produce inexpensive protein biofoams suitable for sponge applications is presented. The protein used in the study was wheat gluten (WG), readily available as a by/co-product, but the method is expected to work for other cross-linkable proteins. The foams were obtained by high-speed stirring of pristine WG powder in water at room temperature followed by drying. Glutaraldehyde was used to crosslink the foam material in order to stabilize the dispersion, reduce its tackiness and improve the strength of the final foam. The foams were of medium to high density and absorbed readily both hydrophobic and hydrophilic liquids. The foam structure, consisting primarily of an open pore/channel system, led to a remarkably fast capillary-driven (pore-filling only) uptake of a hydrophobic liquid (limonene). Essentially all uptake occurred within the first second (to ca. 90% of the dry weight). In a polar liquid (water), the rapid pore-filling occurred in parallel with a more time-dependent swelling of the foam matrix material. Further improvement in the foam strength was achieved by making a denser foam or adding TEMPO-oxidized cellulose nanofibres. Soft foams were obtained by adding glycerol.

  • 33.
    Albertsson, Ann-Christine
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Celebrating 20 years of Biomacromolecules!2019Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, nr 2, s. 767-768Artikel i tidskrift (Refereegranskat)
  • 34.
    Albertsson, Ann-Christine
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    CELL 104-Renewable and/or degradable polymers2007Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 233, s. 796-796Artikel i tidskrift (Övrigt vetenskapligt)
  • 35.
    Albertsson, Ann-Christine
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH Royal Inst Technol, Dept Fiber & Polymer Technol, Stockholm, Sweden..
    Micro- and macromolecular design of aliphatic polyesters2015Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Artikel i tidskrift (Övrigt vetenskapligt)
  • 36.
    Aldabbagh, Zina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    En undersökning av Rönningesjöns miljötillstånd, särskilt när det gäller metaller2018Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Rönningesjön är en sprickdalssjö, som påverkas av lerslätter runt sjön. pH ligger mellan 7,1 och 7,7. Sjön är starkt eutrofierad. Den påverkas också av vägarna runt omkring. Det tillrinnande vattnet innehåller mycket salt från kringliggande vägar. Från bilarna kommer också metaller. I detta projekt mätas koppar, krom och bly. Den större delen av metallerna kommer med dagvattnet till Löttingelunds våtmark och följer sedan med vattnet genom sjön och ut i Hägernäsviken, som är en del av Östersjön. De sedimenterar delvis i sjön. Koncentrationerna av metallerna är alldeles för höga i vattnet. Metaller finns också lagrade i sedimenten. Sedimenteringsdammar bör anläggas för dagvattnet för att avlägsna de partikelbundna metallerna.

  • 37.
    Aldahan, Leith
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Kudoori, Ivan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Utvärdering av roterande borstlösfrekvensomformare tillspårledningar2019Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Spårledningar används inom tunnelbanan för att visa tågets position samt bestämma tågets hastighet genom att bryta spänningsamplituden i signalen vid olika frekvenser. Frekvensen till spårledningen fås från en roterande frekvensomformare. I dagens anläggning används roterande frekvensomformare med borstar. Dessa avger i relärum mycket värme och ger miljöproblem i form av koldamm från borstarna. Det befintliga systemet är gammal och har funnits i drift över 30 år, därför håller reservdelar på att ta slut samt service till systemet svårtillgängligt.

    Detta examensarbete har undersökt möjligheten att uppgradera till nyare system som bygger på en lösning med roterande borstlös frekvensomformare där reservdelarna och service är tillgängliga i minst 25 år.

    Undersökningen jämför olika roterande borstlösa frekvensomformare från olika leverantörer för att hitta en frekvensomformare där kraven från Trafikförvaltningen uppfylls.

    Studien har haft fokus på problemområdet med borstade frekvensomformaren som producerar skadliga ämnen såsom koldamm och värmen i relärum. Diskussioner med tillverkningsföretag av roterande borstlös frekvensomformaren har skett under denna studies gång där möjliga alternativ för vidare utveckling av systemet i relärum analyseras. I projektet har även diskuterat möjligheten att använda det nya systemet av frekvensomformare med borstlösa motor och generator istället för den nuvarande borstade frekvensomformaren som finns i anläggningen. Resultatet har även visat att den roterande borstlösa frekvensomformaren kan omvandla frekvensen till 75 Hz. Det nya systemet uppfyller kraven från Trafikförvaltningen samt att systemet håller i minst 25 år till. Att systemet håller minst i 25 år till var ett stort krav av Trafikförvaltningen som uppfylldes under denna studie.

  • 38.
    Alekseeva, L. A.
    et al.
    Natl Acad Sci Ukraine, B Verkin Inst Low Temp Phys & Engn, 47 Nauky Ave, UA-61103 Kharkov, Ukraine..
    Dobryden, Illia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Determination of the low-temperature self-diffusion coefficient in solid p-H-2 from creep experiments2018Ingår i: Low temperature physics (Woodbury, N.Y., Print), ISSN 1063-777X, E-ISSN 1090-6517, Vol. 44, nr 9, s. 946-951Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dependencies of the relative elongation epsilon under the constantly applied stress at T = 1.8 K on the endurance time t of polycrystalline parahydrogen (p-H-2, similar to 0.2% of o-H-2) of high purity (99.9999 mol.%), with varying deuterium content, were measured. The region of linear dependence between the measured creep rates (epsilon) over dot of samples and the applied stress s was revealed. The conclusion that the low-temperature creep of the studied p-H-2 possesses a vacancy-type diffusion character was made on the basis of linear dependence (epsilon) over dot similar to s. Determination of the low-temperature self-diffusion coefficient of vacancies D in solid p-H-2, which characterizes the rate of low-temperature mass transfer, was performed. The cases of migration of vacancies in the crystal bulk, along boundaries separating individual crystallites, as well as between dislocations existing in crystals, are considered. A significant decrease in the (epsilon) over dot and D values with an increase in the isotope concentration in the samples was observed, while maintaining the linear relationship between (epsilon) over dot and s for the studied p-H-2. Published by AIP Publishing.

  • 39.
    Alemrajabi, Mahmood
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Teknisk strömningslära.
    Recovery of Rare Earth Elements from an Apatite Concentrate2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Rare earth elements (REE) are a group of 17 elements including lanthanides, yttrium and scandium; which are found in a variety of classes of minerals worldwide. The criticality of the application, lack of high grade and economically feasible REE resources and a monopolistic supply situation has raised significant attention in recovery of these metals from low grade ores and waste materials. In this thesis, the recovery of REE from an apatite concentrate, containing 0.5 mass% of REE, within the nitrophosphate route of fertilizer production has been investigated. Most of the REE (≥ 95%) content can be recovered into a phosphate precipitate with almost 30 mass% REE. Different processes have been developed to convert the REE phosphate precipitate into a more soluble form to obtain a solution suitable for further REE purification and individual separation. It has been shown that after reprecipitation of the REE phosphate concentrate as REE sodium double sulphate and then transformation into a REE hydroxide concentrate, a solution containing 45g/L REE free of Ca, Fe and P can be obtained. The results suggest that the apatite waste after processing of iron ore have the potential to be a very important source for REE in Europe and that the economy is strongly supported by the simultaneous extraction of phosphorous.

    The potential of using hollow fiber supported liquid membrane (HFSLM) extraction in individual and group separation of REE has been investigated. A hollow fiber supported liquid membrane plant in pilot scale has been operated according to the three main configurations: standard hollow fiber supported liquid membrane technology (HFSLM); hollow fiber renewal liquid membrane technology (HFRSLM) and emulsion pertraction technology (EPT). The standard HFSLM operation is more selective than HFRSLM and EPT, while higher metal transport rate is observed in EPT followed by HFRSLM and HFSLM. The HFRLM configuration helps to maintain the performance of the liquid membrane.

  • 40.
    Alemrajabi, Mahmood
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Korkmaz, Kivanc
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Rasmuson, Åke
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Dephosphorization and impurity removal from a rare earth phosphate concentrate2017Konferensbidrag (Refereegranskat)
  • 41.
    Alemrajabi, Mahmood
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Korkmaz, Kivanc
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Rasmuson, Åke C.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Isolation of Rare Earth Element Phosphate Precipitates in the Nitrophosphate Process for Manufacturing of Fertilizer2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    In the present study, the recovery of rare earth elements (REE) in the nitrophosphate process of fertilizer production is investigated. The apatite has been recovered from iron ore tailings by flotation. After digestion of apatite in concentrated nitric acid, Ca(NO3)2.4H2O is first separated by cooling crystallization and then the REEs are recovered by precipitation. Optimum conditions in these steps have been determined in a previous study. The precipitate mainly consists of CaHPO4.2H2O and REE phosphates. In the present study, selective dissolution and re-precipitation have been studied in order to obtain a precipitate that is more concentrated in REEs. The precipitate was selectively dissolved in nitric and phosphoric acid at different acidities (pH 6 to 0) with the liquid /solid ratio of 100 mL/g. It is shown that most of the CaHPO4.2H2O and other calcium containing compounds will be dissolved at pH 2 while the REE phosphates are not dissolved above a pH of approximately 2. Thus, by partial dissolution of the REE precipitate at pH 2.5 most of the solid calcium phosphates will be dissolved and the remaining solid phase, which is more concentrated in REEs, can be filtered off as a fairly concentrated REE solid mass and the liquor can be recycled back to recover more P nutrients. Alternatively, the REE enriched precipitate was dissolved completely in nitric acid and re-precipitated again by addition of ammonium hydroxide to pH 1.2. A chemical equilibrium software, MEDUSA (Puigdomenech, 2013) has been used to evaluate the experimental results and to estimate the optimum conditions for selectively dissolving the precipitate.

  • 42.
    Alemrajabi, Mahmood
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Rasmuson, Åke
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Recovery of phosphorous and rare earth elements from an apatite concentrate2018Konferensbidrag (Refereegranskat)
  • 43.
    Alemrajabi, Mahmood
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Rasmuson, Åke
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Korkmaz, Kivanc
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Upgrading of a rare earth phosphate concentrate within the nitrophosphate process2018Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 198, s. 551-563Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the nitrophosphate process of fertilizer production, rare earth elements (REE) can be recovered as a REE phosphate concentrate. In this process, after digestion of apatite in concentrated nitric acid, Ca(NO3)2.4H2O is first separated by cooling crystallization and then the REE are precipitated in phosphate form by a partial neutralization step using ammonia. The obtained REE phosphate concentrate is contaminated by mainly calcium and iron, and the main solid phases are CaHPO4.2H2O, FePO4.2H2O and REEPO4.nH2O.

    In this study, a process to obtain a concentrate more enriched with REE with low concentration of calcium and iron and free of phosphorous is developed. In the developed process, enrichment and dephosphorization of the rare earth phosphate concentrate has been achieved by selective dissolution and re-precipitation of the REE as a sodium REE double sulfate salt. It is shown that by selective dissolution of the REE concentrate in nitric acid at a pH of 2.4, most of the calcium and phosphorus are dissolved, and a solid phase more enriched in REE is obtained. Thereafter, the REE phosphate concentrate is first dissolved in a mixture of sulfuric-phosphoric acid and then the REE are reprecipitated as NaREE(SO4)2.H2O by addition of a sodium salt. More than 95% of the Ca, Fe and P are removed and a REE concentrate containing almost 30 mass% total REE is obtained.

  • 44.
    Alemrajabi, Mahmoud
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Rasmuson, Åke
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Recovery of REE from an apatite concentrate in the nitrophosphate process of fertilizer production.2015Konferensbidrag (Refereegranskat)
  • 45.
    Alexakis, Alexandros Efraim
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Preparation and Testing of FDCA based Nanocomposites2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The project focuses on the use of diallyl 2,5-furanedicarboxylate (DAFDC) as a bio-based alternative for phthalic acid based thermosets. Initially, kinetic analysis, by means of Borchardt and Daniels method was performed to study the curing conditions. However, this model gave inaccurate results mainly due to different conditions apparent during Differential Scanning Calorimetry (DSC) measurement which were not able to be simulated in the experimental procedure that was followed. Nevertheless, by curing DAFDC with  of dicumyl peroxide (DCP), which comprise the matrix, and incorporating graphene oxide nanodots (GONDs) and carbon nanotubes (CNTs) in different weight amounts, in a staggered temperature and time fashion, nanocomposites based on DAFDC were produced. GONDs were oxidized from carbon nanospheres (CNs). The latter were produced from cellulose by adding a dialysis step in the protocol found in the literature 2.

    Through the characterization of the nanocomposites, it was concluded that the above protocol resulted in partially crosslinked materials which were further cured at elevated temperatures during Dynamical Mechanical Analysis (DMA). The fully crosslinked nanocomposites produced from this heating ramp exhibited enhanced properties. More specifically, the degradation temperature corresponding to  loss of mass, i.e. , seemed to be unaffected by the filler content and compared to the matrix it was enhanced by roughly  and  for GOND-filled and CNT-filled nanocomposites, respectively. Conductivity measurements gave an insight on the percolation threshold of the produced nanocomposites. On the one hand, CNT-filled nanocomposites exhibited a percolation threshold at  of CNT and their conductivity was increasing by increasing filler content. On the other hand, for GOND-filled nanocomposites, the filler content seemed to be lower than this threshold, since no electrical conductivity value could be monitored. The mechanical testing showed indications of enhanced properties of the fully cured nanocomposites compared to their partially cured analogues. However, due to the geometry and breaking of the cured samples during DMA, the mechanical properties could not be verified. Finally, the morphology of the nanocomposites was investigated by means of digital microscopy. Both sides of the samples were studied, since the side that was in contact with oxygen during curing, exhibited different morphological behavior than the side that was not in contact with oxygen. In particular, the side which was in contact with oxygen, showed a smoother surface than the side which was in contact with the mold.

    In conclusion, the possibility to produce a bio-based alternative of phthalic acid based thermosets was verified, giving the opportunity to eagerly investigate this monomer in different applications in the future.

  • 46.
    Alfrijat, Christopher
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Eriksson, Rasmus
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Analys och utvärdering av LED-belysning i Stockholms tunnelbana2019Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Trafikförvaltningen, som ansvarar för kollektivtrafiken i Stockholm, har startat ett projekt för att byta ut befintliga armaturer i Stockholms tunnelbana mot LED-armaturer. Denna rapport utför förarbetet inför en kommande upphandling.

    Detta arbete utvärderar olika LED-armaturers tekniska specifikationer som är lämpliga för Stockholms tunnelbana där armaturerna ska bytas ut. För denna miljö saknas det i dagsläget standarder som är anpassade för LED-armaturer. Med hjälp av litteraturstudier och mätningar kunde underlag för en kravspecifikation skapas. Mätningar har gjorts på ett urval av LED-armaturer och deras tekniska specifikation har presenterats. Samtliga armaturer klarade EMC-testerna (elektromagnetisk kompabilitet) där inga störningar uppstod vid frekvenserna för Storstockholms Lokaltrafiks (SL) radiokommunikationssystem.

    Arbetet har även hanterat miljö- samt den ekonomiska aspekten av implementeringen av LED-belysning.

  • 47.
    Ali pour, Nazanin
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Enebro, J.
    Strömberg, Emma
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Qualitative characterization of nanoclay particle emissions from PP nanocomposites after thermal degradation2015Ingår i: ICCM International Conferences on Composite Materials, International Committee on Composite Materials , 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    The use of nanomaterials in polymeric materials is a rapidly expanding field, and the polymer nanocomposites are being introduced into various markets. But there is still little known about the fate of nanocomposites and nanoparticles during service life and end-of-life of the materials. To avoid possible environmental, health and safety problems, simulating different scenarios for nanoparticles release from the polymer matrix plays a key role in commercialization of these advanced materials. The polymer/nanoclay nanocomposites show superior material properties in comparison with the pure polymers, such as improved mechanical properties, heat resistance, flame retardancy and decreased gas permeability. Polypropylene (PP) nanocomposites have attracted a considerable interest due to the material's low cost, low density and extensive production volumes. In this study, in order to obtain reliable results regarding the release of nanoclays from PP nanocomposites, homogenous composite with predetermined content of nanoclay was produced and characterized to obtain information regarding content, dispersion and size of the nanoclays in the matrix. The PP nanocomposite was degraded under controlled conditions and the surface morphology as well as oxidation of the material was characterized with scanning electron microscopy (SEM) and infrared spectroscopy during degradation. A prototype environmental chamber was designed in order to collect nano-sized particles in a controlled manner and subsequent characterization of the released or formed particles was performed with transmission electron microscopy (TEM) and the exposed nanocomposite was analysed with thermogravimetric analysis (TGA). 

  • 48.
    Alipour, Nazanin
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Vinneras, Bjorn
    SLU Swedish Univ Agr Sci, Dept Energy & Technol, POB 7032, SE-75007 Uppsala, Sweden..
    Gouanve, Fabrice
    Univ Lyon 1, Univ Lyon, Ingn Mat Polymeres, CNRS,UMR 5223, 15 Bd Andre Latarjet, F-69622 Villeurbanne, France..
    Espuche, Eliane
    Univ Lyon 1, Univ Lyon, Ingn Mat Polymeres, CNRS,UMR 5223, 15 Bd Andre Latarjet, F-69622 Villeurbanne, France..
    Hedenqvist, Mikael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    A Protein-Based Material from a New Approach Using Whole Defatted Larvae, and Its Interaction with Moisture2019Ingår i: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 11, nr 2, artikel-id 287Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A protein-based material created from a new approach using whole defatted larvae of the Black Soldier fly is presented. The larvae turn organic waste into their own biomass with high content of protein and lipids, which can be used as animal feed or for material production. After removing the larva lipid and adding a plasticizer, the ground material was compression molded into plates/films. The lipid, rich in saturated fatty acids, can be used in applications such as lubricants. The amino acids present in the greatest amounts were the essential amino acids aspartic acid/asparagine and glutamic acid/glutamine. Infrared spectroscopy revealed that the protein material had a high amount of strongly hydrogen-bonded beta-sheets, indicative of a highly aggregated protein. To assess the moisture-protein material interactions, the moisture uptake was investigated. The moisture uptake followed a BET type III moisture sorption isotherm, which could be fitted to the Guggenheim, Anderson and de Boer (GAB) equation. GAB, in combination with cluster size analysis, revealed that the water clustered in the material already at a low moisture content and the cluster increased in size with increasing relative humidity. The clustering also led to a peak in moisture diffusivity at an intermediate moisture uptake.

  • 49.
    Aljure, Mauricio
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Becerra Garcia, Marley
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknisk teori och konstruktion.
    Karlsson, Mattias
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Erratum to: Aljure, M.; Becerra, M.; Karlsson, E.M. Streamer inception from ultra-sharp needles in mineral oil based nanofluids2018Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 11, nr 11, artikel-id 2900Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The authors wish to make the following corrections to their paper [1]: i. On pages 13 and 14, the numbering of references from 17 to 30 is incorrect. References 17 to 30 should be renumbered from the original order below: 17. Liu, Z.; Liu, Q.; Wang, Z.D.; Jarman, P.; Krause, C.; Smith, P.W.R.; Gyore, A. Partial discharge behaviour of transformer liquids and the influence of moisture content. In Proceedings of the 2014 IEEE 18th International Conference on Dielectric Liquids (ICDL), Bled, Slovenia, 29 June–3 July 2014. 18. Yamashita, H.; Yamazawa, K.; Wang, Y.S. The effect of tip curvature on the prebreakdown streamer structure in cyclohexane. IEEE Trans. Dielectr. Electr. Insul. 1998, 5, 396–401. 19. Dumitrescu, L.; Lesaint, O.; Bonifaci, N.; Denat, A.; Notingher, P. Study of streamer inception in cyclohexane with a sensitive charge measurement technique under impulse voltage. J. Electrostat. 2001, 53, 135–146. 20. Pourrahimi, A.M.; Hoang, T.A.; Liu, D.; Pallon, L.K.H.; Gubanski, S.; Olsson, R.T.; Gedde, U.W.; Hedenqvist, M.S. Highly efficient interfaces in nanocomposites based on polyethylene and ZnO nano/hierarchical particles: A novel approach toward ultralow electrical conductivity insulations. Adv. Mater. 2016, 28, 8651–8657. 21. Li, J.; Du, B.; Wang, F.; Yao, W.; Yao, S. The effect of nanoparticle surfactant polarization on trapping depth of vegetable insulating oil-based nanofluids. Phys. Lett. A 2016, 380, 604–608. 22. Aljure, M.; Becerra, M.; Pallon, L.K.H. Electrical conduction currents of a mineral oil-based nanofluid in needle-plane configuration. In Proceedings of the 2016 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP), Toronto, ON, Canada, 16–19 October 2016; pp. 687–690. 23. Primo, V.A.; Garcia, B.; Albarracin, R. Improvement of transformer liquid insulation using nanodielectric fluids: A review. IEEE Electr. Insul. Mag. 2018, 34, 13–26. 24. Jin, H.; Andritsch, T.; Morshuis, P.H.F.; Smit, J.J. AC breakdown voltage and viscosity of mineral oil based SiO2 nanofluids. In Proceedings of the 2012 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, Montreal, QC, Canada, 14–17 October 2012; pp. 902–905. 25. Jin, H.; Morshuis, P.; Mor, A.R.; Smit, J.J.; Andritsch, T. Partial discharge behavior of mineral oil based nanofluids. IEEE Trans. Dielectr. Electr. Insul. 2015, 22, 2747–2753. 26. Du, Y.; Lv, Y.; Li, C.; Chen, M.; Zhong, Y.; Zhou, J.; Li, X.; Zhou, Y. Effect of semiconductive nanoparticles on insulating performances of transformer oil. IEEE Trans. Dielectr. Electr. Insul. 2012, 19, 770–776. 27. Dung, N.V.; Høidalen, H.K.; Linhjell, D.; Lundgaard, L.E.; Unge, M. Effects of reduced pressure and additives on streamers in white oil in long point-plane gap. J. Phys. D Appl. Phys. 2013, 46, 255501. 28. McCool, J.I. Using the Weibull Distribution; John Wiley & Sons, Inc.: Hoboken, NJ, USA, 2012. 29. Lesaint, O.L.; Top, T.V. Streamer initiation in mineral oil. part I: Electrode surface effect under impulse voltage. IEEE Trans. Dielectr. Electr. Insul. 2002, 9, 84–91. 30. Becerra, M.; Frid, H.; Vázquez, P.A. Self-consistent modeling of laminar electrohydrodynamic plumes from ultra-sharp needles in cyclohexane. Phys. Fluids 2017, 29, 123605. to the following, corrected numbering: 17. Dumitrescu, L.; Lesaint, O.; Bonifaci, N.; Denat, A.; Notingher, P. Study of streamer inception in cyclohexane with a sensitive charge measurement technique under impulse voltage. J. Electrostat. 2001, 53, 135–146. 18. Liu, Z.; Liu, Q.; Wang, Z.D.; Jarman, P.; Krause, C.; Smith, P.W.R.; Gyore, A. Partial discharge behaviour of transformer liquids and the influence of moisture content. In Proceedings of the 2014 IEEE 18th International Conference on Dielectric Liquids (ICDL), Bled, Slovenia, 29 June–3 July 2014. 19. Yamashita, H.; Yamazawa, K.; Wang, Y.S. The effect of tip curvature on the prebreakdown streamer structure in cyclohexane. IEEE Trans. Dielectr. Electr. Insul. 1998, 5, 396–401. 20. Becerra, M.; Frid, H.; Vázquez, P.A. Self-consistent modeling of laminar electrohydrodynamic plumes from ultra-sharp needles in cyclohexane. Phys. Fluids 2017, 29, 123605. 21. Pourrahimi, A.M.; Hoang, T.A.; Liu, D.; Pallon, L.K.H.; Gubanski, S.; Olsson, R.T.; Gedde, U.W.; Hedenqvist, M.S. Highly efficient interfaces in nanocomposites based on polyethylene and ZnO nano/hierarchical particles: A novel approach toward ultralow electrical conductivity insulations. Adv. Mater. 2016, 28, 8651–8657. 22. Li, J.; Du, B.; Wang, F.; Yao, W.; Yao, S. The effect of nanoparticle surfactant polarization on trapping depth of vegetable insulating oil-based nanofluids. Phys. Lett. A 2016, 380, 604–608. 23. Aljure, M.; Becerra, M.; Pallon, L.K.H. Electrical conduction currents of a mineral oil-based nanofluid in needle-plane configuration. In Proceedings of the 2016 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP), Toronto, ON, Canada, 16–19 October 2016; pp. 687–690. 24. Primo, V.A.; Garcia, B.; Albarracin, R. Improvement of transformer liquid insulation using nanodielectric fluids: A review. IEEE Electr. Insul. Mag. 2018, 34, 13–26. 25. Jin, H.; Andritsch, T.; Morshuis, P.H.F.; Smit, J.J. AC breakdown voltage and viscosity of mineral oil based SiO2 nanofluids. In Proceedings of the 2012 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, Montreal, QC, Canada, 14–17 October 2012; pp. 902–905. 26. Jin, H.; Morshuis, P.; Mor, A.R.; Smit, J.J.; Andritsch, T. Partial discharge behavior of mineral oil based nanofluids. IEEE Trans. Dielectr. Electr. Insul. 2015, 22, 2747–2753. 27. Du, Y.; Lv, Y.; Li, C.; Chen, M.; Zhong, Y.; Zhou, J.; Li, X.; Zhou, Y. Effect of semiconductive nanoparticles on insulating performances of transformer oil. IEEE Trans. Dielectr. Electr. Insul. 2012, 19, 770–776. 28. Dung, N.V.; Høidalen, H.K.; Linhjell, D.; Lundgaard, L.E.; Unge, M. Effects of reduced pressure and additives on streamers in white oil in long point-plane gap. J. Phys. D Appl. Phys. 2013, 46, 255501. 29. McCool, J.I. Using the Weibull Distribution; John Wiley & Sons, Inc.: Hoboken, NJ, USA, 2012. 30. Lesaint, O.L.; Top, T.V. Streamer initiation in mineral oil. part I: Electrode surface effect under impulse voltage. IEEE Trans. Dielectr. Electr. Insul. 2002, 9, 84–91. ii. On the last paragraph of page 9, the last sentence should be changed from: However, the results in [11] also show the consistent increase in the initiation voltage of prebreakdown phenomena in both polarities, as reported in Figure 11. to the following, corrected version: However, the results in [26] also show the consistent increase in the initiation voltage of prebreakdown phenomena in both polarities, as reported in Figure 11. iii. On the last paragraph of page 10, the third sentence should be changed from: Even though the existing hypotheses of the dielectric effect of NPs [8–10] were proposed for blunter electrodes (where charge generation before streamer initiation is less important [30]), they should still apply under the experimental conditions here reported. to the following, corrected version: Even though the existing hypotheses of the dielectric effect of NPs [5,6,16] were proposed for blunter electrodes (where charge generation before streamer initiation is less important [30]), they should still apply under the experimental conditions here reported. The authors would like to apologize for any inconvenience caused to the readers by these changes. The changes do not affect the scientific results. The manuscript will be updated and the original will remain online on the article webpage, with a reference to this Correction.

  • 50.
    Aljure, Mauricio
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Becerra Garcia, Marley
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknisk teori och konstruktion. ABB Corp Res, Vasteras, Sweden..
    Karlsson, Mattias E.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    On the injection and generation of charge carriers in mineral oil under high electric fields2019Ingår i: JOURNAL OF PHYSICS COMMUNICATIONS, ISSN 2399-6528, Vol. 3, nr 3, artikel-id UNSP 035019Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Charge injection and generation mechanisms under intense electric fields (up to 10(9)Vm(-1)) in mineral oil are assessed experimentally and numerically. For this, current-voltage characteristics under positive and negative polarities are measured in a needle-plane configuration using sharp needles (with tip radius R-tip <= 1.1 mu m). In addition, a state of the art electro-hydrodynamic (EHD) model is implemented to calculate the contribution of the different mechanisms on the high-field conduction currents in the liquid. In order to evaluate exclusively the contribution of field emission, experiments are also performed in vacuum. It is found that neither field emission nor field ionisation can explain the conduction currents measured in mineral oil. It is proposed that field molecular ionisation, as described by Zener tunnelling model for solids, and electron impact ionisation are the processes dominating the generation of excess electron-ion pairs in mineral oil under positive and negative polarity, respectively. It is also shown that Zener molecular ionisation alone grossly overestimates the measured currents when parameters previously suggested in the literature for mineral oil are used. Preliminary model parameters for these mechanisms that best fit the conduction currents measured in mineral oil are presented and discussed.

1234567 1 - 50 av 1845
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • 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