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  • 1.
    Aaen, Ragnhild
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Lehtonen, Mari
    University of Helsinki, Finland.
    Mikkonen, Kirsi
    University of Helsinki, Finland.
    Syverud, Kristin
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design. NTNU Norwegian University of Science and Technology, Norway.
    Combining cellulose nanofibrils and galactoglucomannans for enhanced stabilization of future food emulsions2021In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 28, no 16, p. 10485-10500Article in journal (Refereed)
    Abstract [en]

    The use of wood-derived cellulose nanofibrils (CNFs) or galactoglucomannans (GGM) for emulsion stabilization may be a way to obtain new environmentally friendly emulsifiers. Both have previously been shown to act as emulsifiers, offering physical, and in the case of GGM, oxidative stability to the emulsions. Oil-in-water emulsions were prepared using highly charged (1352 ± 5 µmol/g) CNFs prepared by TEMPO-mediated oxidation, or a coarser commercial CNF, less charged (≈ 70 µmol/g) quality (Exilva forte), and the physical emulsion stability was evaluated by use of droplet size distributions, micrographs and visual appearance. The highly charged, finely fibrillated CNFs stabilized the emulsions more effectively than the coarser, lower charged CNFs, probably due to higher electrostatic repulsions between the fibrils, and a higher surface coverage of the oil droplets due to thinner fibrils. At a constant CNF/oil ratio, the lowest CNF and oil concentration of 0.01 wt % CNFs and 5 wt % oil gave the most stable emulsion, with good stability toward coalescence, but not towards creaming. GGM (0.5 or 1.0 wt %) stabilized emulsions (5 wt % oil) showed no creaming behavior, but a clear bimodal distribution with some destabilization over the storage time of 1 month. Combinations of CNFs and GGM for stabilization of emulsions with 5 wt % oil, provided good stability towards creaming and a slower emulsion destabilization than for GGM alone. GGM could also improve the stability towards oxidation by delaying the initiation of lipid oxidation. Use of CNFs and combinations of GGM and CNFs can thus be away to obtain stable emulsions, such as mayonnaise and beverage emulsions. © 2021, The Author(s).

  • 2. Aarts, Mark
    et al.
    Reiser, Alain
    Laboratory for Nanometallurgy, ETH Zürich, Department of Materials, Vladimir-Prelog-Weg 1-5/10, Zürich, Switzerland.
    Spolenak, Ralph
    Alarcon-Llado, Esther
    Confined pulsed diffuse layer charging for nanoscale electrodeposition with an STM2022In: Nanoscale Advances, ISSN 25160230, Vol. 4, no 4, p. 1182-1190Article in journal (Refereed)
  • 3.
    Abali, Bilen Emek
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics.
    Yardimci, Mert Yucel
    Univ Ghent, Magnel Vandepitte Lab, Dept Struct Engn & Bldg Mat, Technol Pk Zwijnaarde 60, B-9052 Ghent, Belgium.;Istanbul Okan Univ, Dept Civil Engn, TR-34959 Istanbul, Turkey..
    Zecchini, Michele
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria..
    Daisse, Gilda
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria..
    Marchesini, Flavio H.
    Univ Ghent, Dept Mat Text & Chem Engn, Technol Pk Zwijnaarde 130, B-9052 Ghent, Belgium..
    De Schutter, Geert
    Univ Ghent, Magnel Vandepitte Lab, Dept Struct Engn & Bldg Mat, Technol Pk Zwijnaarde 60, B-9052 Ghent, Belgium..
    Wan-Wendner, Roman
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria.;Univ Ghent, Magnel Vandepitte Lab, Dept Struct Engn & Bldg Mat, Technol Pk Zwijnaarde 60, B-9052 Ghent, Belgium..
    Experimental investigation for modeling the hardening of thermosetting polymers during curing2021In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 102, article id 107310Article in journal (Refereed)
    Abstract [en]

    During curing of thermosetting polymers, crosslinking results in hardening or stiffening of the material. In electronics, for example in encapsulating integrated circuits (die bonding), thermosets are fully cured in a controlled environment (under UV-light or within a thermal oven) such that the highest stiffness possible has been achieved. In building materials, specifically in thermosets used in fastening systems (adhesive anchoring), hardening occurs at environmental temperature. Daily temperature variations alter the curing process and possibly lead to a lower stiffness. We demonstrate a modeling approach for the mechanical response dependency on the degree of cure by means of rheometer measurements under a specific temperature profile. Precisely, we perform oscillatory rheometric tests and convert the storage and loss moduli to material parameters depending on the degree of cure. Moreover, the temperature dependency as well as chemical shrinkage have been determined by the same experimental protocol. The presented approach has been applied to a commercially available (epoxy) thermoset used as an adhesive. We have observed a hardening after a gelation point of 0.7 and an adequate fit for mechanical response by polynomial functions of degree four.

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  • 4.
    Abarkan, Myriam
    et al.
    Univ Bordeaux, France.
    Pirog, Antoine
    Univ Bordeaux, France.
    Mafilaza, Donnie
    Univ Bordeaux, France.
    Pathak, Gaurav
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. MOC, France.
    NKaoua, Gilles
    Univ Bordeaux, France.
    Puginier, Emilie
    Univ Bordeaux, France.
    OConnor, Rodney
    MOC, France.
    Raoux, Matthieu
    Univ Bordeaux, France.
    Donahue, Mary
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. MOC, France.
    Renaud, Sylvie
    Univ Bordeaux, France.
    Lang, Jochen
    Univ Bordeaux, France.
    Vertical Organic Electrochemical Transistors and Electronics for Low Amplitude Micro-Organ Signals2022In: Advanced Science, E-ISSN 2198-3844, Vol. 9, no 8, article id 2105211Article in journal (Refereed)
    Abstract [en]

    Electrical signals are fundamental to key biological events such as brain activity, heartbeat, or vital hormone secretion. Their capture and analysis provide insight into cell or organ physiology and a number of bioelectronic medical devices aim to improve signal acquisition. Organic electrochemical transistors (OECT) have proven their capacity to capture neuronal and cardiac signals with high fidelity and amplification. Vertical PEDOT:PSS-based OECTs (vOECTs) further enhance signal amplification and device density but have not been characterized in biological applications. An electronic board with individually tuneable transistor biases overcomes fabrication induced heterogeneity in device metrics and allows quantitative biological experiments. Careful exploration of vOECT electric parameters defines voltage biases compatible with reliable transistor function in biological experiments and provides useful maximal transconductance values without influencing cellular signal generation or propagation. This permits successful application in monitoring micro-organs of prime importance in diabetes, the endocrine pancreatic islets, which are known for their far smaller signal amplitudes as compared to neurons or heart cells. Moreover, vOECTs capture their single-cell action potentials and multicellular slow potentials reflecting micro-organ organizations as well as their modulation by the physiological stimulator glucose. This opens the possibility to use OECTs in new biomedical fields well beyond their classical applications.

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  • 5.
    Abas, Naeem
    et al.
    University of Gujrat, Hafiz Hayat Campus, Pakistan.
    Kalair, Ali Raza
    COMSATS University Islamabad, Pakistan.
    Seyedmahmoudian, Mehdi
    Swinburne University, Australia.
    Naqvi, Muhammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Campana, Pietro Elia
    Mälardalen University, Sweden.
    Khan, Nasrullah
    COMSATS University Islamabad, Pakistan.
    Dynamic simulation of solar water heating system using supercritical CO2 as mediating fluid under sub-zero temperature conditions2019In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 161, article id 114152Article in journal (Refereed)
    Abstract [en]

    CO2 is becoming increasingly important as a mediating fluid, and simulation studies are indispensable for corresponding developments. In this study, a simulation-based performance investigation of a solar water heating system using CO2 as a mediating fluid under sub-zero temperature condition is performed using the TRNSYS (R) software. The maximum performance is achieved at a solar savings fraction of 0.83 during July. The as lowest solar savingss fraction of 0.41 is obtained during December. The annual heat production of the proposed system under Fargo climate is estimated to be about 2545 kWh. An evacuated glass tube solar collector is designed, fabricated and tested for various climate conditions. Moreover, a detailed comparison of the system's performance at sub/supercritical and supercritical pressures shows that the annual heat transfer efficiency of the modeled system is 10% higher at supercritical pressure than at sub/supercritical pressures. This result can be attributd to the strong convection flow of CO2 caused by density inhomogeneities, especially in the near critical region. This condition resuls in high heat transfer rates.

  • 6.
    Abbadessa, Anna
    et al.
    KTH Royal institute of Technology, Sweden.
    Dogaris, Ioannis
    KTH Royal institute of Technology, Sweden.
    Kishani Farahani, Saina
    KTH Royal institute of Technology, Sweden.
    Reid, Michael S.
    KTH Royal institute of Technology, Sweden.
    Rautkoski, Hille
    VTT Technical Research Centre of Finland, Finland.
    Holopainen-Mantila, Ulla
    VTT Technical Research Centre of Finland, Finland.
    Oinonen, Petri
    Ecohelix, Sweden.
    Henriksson, Gunnar
    KTH Royal institute of Technology, Sweden.
    Layer-by-layer assembly of sustainable lignin-based coatings for food packaging applications2023In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 182, article id 107676Article in journal (Refereed)
    Abstract [en]

    Packaging plays a critical role in ensuring food safety and shelf life by protecting against e.g., moisture, gases, and light. Polyethylene (PE) is widely used in food packaging, but it is mainly produced from non-renewable resources and it is an inefficient oxygen and light barrier. In this study, the layer-by-layer (LbL) assembly of a sustainably produced lignin-based polymer (EH) with polyethylenimine (PEI) or chitosan (CH) was used to fabricate (partially or fully) bio-based coatings with the aim of improving barrier properties of PE films. The charge density of EH was calculated using a polyelectrolyte titration method and the hydrodynamic diameters of EH, PEI and CH were determined by Dynamic Light Scattering (DLS). LbL assembly was monitored in situ via Quartz Crystal Microbalance with Dissipation (QCM-D) and Stagnation Point Adsorption Reflectometry (SPAR). PE films were coated with a variable number of PEI/EH or CH/EH bilayers (BL) using an immersive LbL assembly method. Coated films were studied in terms of light-blocking ability, wettability, thermal behaviour, surface structure, as well as oxygen and water vapor barrier properties. QCM-D and SPAR data showed a stepwise multilayer formation and strong interactions between the oppositely charged polymers, with PEI/EH coating having a greater amount of deposited polymer compared to CH/EH coating at the same number of BL. Overall, light barrier properties and wettability of the coated films increased with the number of deposited bilayers. Coated PE films maintained the overall thermal behaviour of PE. A number of BL of 20 was found to be the most promising based on the studied properties. Selected samples showed improved oxygen and water vapor barrier properties, with PEI/EH coating performing better than CH/EH coating. Taken altogether, we demonstrated that a novel and sustainable lignin-based polymer can be combined with PEI or CH to fabricate (partially or fully) bio-based coatings for food packaging. 

  • 7.
    Abbas, Malik Waseem
    et al.
    Natl Inst Biotechnol and Genet Engn, Pakistan.
    Soomro, Razium Ali
    Natl Inst Biotechnol and Genet Engn, Pakistan; Univ Sindh, Pakistan; Univ Bristol, England.
    Kalwar, Nazar Hussain
    Shah Abdul Latif Univ, Pakistan.
    Zahoor, Mehvish
    Natl Inst Biotechnol and Genet Engn, Pakistan.
    Avci, Ahmet
    Selcuk Univ, Turkey.
    Pehlivan, Erol
    Selcuk Univ, Turkey.
    Hallam, Keith Richard
    Univ Bristol, England.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Carbon quantum dot coated Fe3O4 hybrid composites for sensitive electrochemical detection of uric acid2019In: Microchemical journal (Print), ISSN 0026-265X, E-ISSN 1095-9149, Vol. 146, p. 517-524Article in journal (Refereed)
    Abstract [en]

    The study explores carbon quantum dots (C-dots) as potential candidates for enhancing the signal sensitivity of an electrochemical sensor devised for biologically important molecule, such as uric acid (UA). The C-dots were evaluated for their electrochemical characteristics in combination with Fe3O4 nanoparticles (Fe3O4 NPs), which were applied as the primary electro-catalytic promoter. The hybrid nanocomposite (C-dots/Fe3O4 HCs) formation was achieved by facilitating the adsorption of C-dots over Fe3O4 NPs using amine-carbonyl interactions. Unlike, one pot method, the proposed strategy enables aggregation-free coverage of Fe3O4 NPs with highly conductive layer of C-dots that can act as conduction centres to support ultra-fast electron transfer kinetics to satisfy the need of high signal sensitivity. The hybrid composite demonstrated remarkable signal improvement when tested against the electrochemical oxidation of UA. The heighten current response and lower over-potential values enabled development of a DC-amperometric (DC-AMP) sensor for UA with a linear working range of 0.01 to 0.145 mu M and signal sensitivity measurable up to 6.0 x 10(-9) M. The said improvement was manifested as a synergetic outcome of active redox couple (Fe (III/II)), larger surface area of Fe3O4 NPs engulfed with a layer of highly conductive C-dots acting as efficient charge sensitisers.

  • 8.
    Abbas, Shahrukh
    et al.
    National University of Sciences & Technology, PAK.
    Kazmi, Syed Ali
    National University of Sciences & Technology, PAK.
    Naqvi, Muhammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Javed, Adeel
    National University of Sciences & Technology, PAK.
    Naqvi, SR
    National University of Sciences & Technology, PAK.
    Ullah, Kafait
    National University of Sciences & Technology, PAK.
    Khan, Tauseef
    Natl Transmiss & Dispatch Co NTDC, PAK.
    Shin, Dong
    SungKyunKwan Univ SKKU, KOR.
    Impact Analysis of Large-Scale Wind Farms Integration in Weak Transmission Grid from Technical Perspectives2020In: Energies, E-ISSN 1996-1073, Vol. 13, no 20, article id 5513Article in journal (Refereed)
    Abstract [en]

    The integration of commercial onshore large-scale wind farms into a national grid comes with several technical issues that predominately ensure power quality in accordance with respective grid codes. The resulting impacts are complemented with the absorption of larger amounts of reactive power by wind generators. In addition, seasonal variations and inter-farm wake effects further deteriorate the overall system performance and restrict the optimal use of available wind resources. This paper presented an assessment framework to address the power quality issues that have arisen after integrating large-scale wind farms into weak transmission grids, especially considering inter-farm wake effect, seasonal variations, reactive power depletion, and compensation with a variety of voltage-ampere reactive (Var) devices. Herein, we also proposed a recovery of significant active power deficits caused by the wake effect via increasing hub height of wind turbines. For large-scale wind energy penetration, a real case study was considered for three wind farms with a cumulative capacity of 154.4 MW integrated at a Nooriabad Grid in Pakistan to analyze their overall impacts. An actual test system was modeled in MATLAB Simulink for a composite analysis. Simulations were performed for various scenarios to consider wind intermittency, seasonal variations across four seasons, and wake effect. The capacitor banks and various flexible alternating current transmission systems (FACTS) devices were employed for a comparative analysis with and without considering the inter-farm wake effect. The power system parameters along with active and reactive power deficits were considered for comprehensive analysis. Unified power flow controller (UPFC) was found to be the best compensation device through comparative analysis, as it maintained voltage at nearly 1.002 pu, suppressed frequency transient in a range of 49.88-50.17 Hz, and avoided any resonance while maintaining power factors in an allowable range. Moreover, it also enhanced the power handling capability of the power system. The 20 m increase in hub height assisted the recovery of the active power deficit to 48%, which thus minimized the influence of the wake effect.

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  • 9. Abbas, Sk Jahir
    et al.
    Ramacharyulu, P. V. R. K.
    Lo, Hsin-Hsi
    Ali, Sk Imran
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Ke, Shyue-Chu
    A catalytic approach to synthesis of PLP analogs and other environmental protocols in a single handed CaO/TiO2 green nanoparticle2017In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 210, p. 276-289Article in journal (Refereed)
    Abstract [en]

    As our precursory stage we have focus straight forward on clean catalytic approach for the production of C3 substituted pyridoxal-5 '-phosphate analogues of vitamin B6, and other environmental protocols like photocatalytic activity, green fossil fuels and c-c coupling using efficient biocompatible eggshell related unrivalled materials which show versatility of the catalytic effect on different inorganic support. The eggshell immobilized nanoparticles have encouraging relevance in creation of new molecules and can advantageously be studied by various spectroscopic, thermal and elemental analyses like powder X-ray diffraction (XRD), Raman spectroscopy, UV-vis, Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area analysis. The elucidate nature of nanoparticles offer: more active site acts as lewis acid, vacancies on the catalyst surface and good to better yield of C3 substituted deoxy and 2-nor deoxy coenzyme pyridoxine (PN), coupling products propargylamines (PA), photo degrading enhancement of MB and nucleophilic substituted fatty acid (BD). This enzyme cofactor explore molecular synthons to synthetic equivalent: 3-deoxy and 2-nor-3-deoxy pyridoxal (PL), pyridoxal oxime (P0), pyridoxamine (PM) and mono phosphate derivative of 3-deoxyPM, 3-deoxyPL respectively and chemistry of selective oxidation and schiff base mechanism was studied and complemented through combined experimental and theoretical molecular orbital calculation consequently. The heterogeneous catalyst has strong selective ability towards selective reducing pyridine diester, bioactive intermediates substances and holds vast potential towards separation for the photogenerated electron-hole pairs and renewable, nontoxic, biodegradable green fossil fuels. The catalyst including environmental concern is reapplicable and strong impressive that can unfold the space of worthy metal component widely and facilitate the scope to take a vital role in different fileds like catalysis, biochemistry, nanoscience, energy and materials science.

  • 10. Abbasalizadeh, Aida
    et al.
    Malfliet, Annelies
    Seetharaman, Seshadri
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Sietsma, Jilt
    Yang, Yongxiang
    Electrochemical Extraction of Rare Earth Metals in Molten Fluorides: Conversion of Rare Earth Oxides into Rare Earth Fluorides Using Fluoride Additives2017In: JOURNAL OF SUSTAINABLE METALLURGY, ISSN 2199-3823, Vol. 3, no 3, p. 627-637Article in journal (Refereed)
    Abstract [en]

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

  • 11. Abbasalizadeh, Aida
    et al.
    Malfliet, Annelies
    Seetharaman, Seshadri
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Sietsma, Jilt
    Yang, Yongxiang
    Electrochemical Recovery of Rare Earth Elements from Magnets: Conversion of Rare Earth Based Metals into Rare Earth Fluorides in Molten Salts2017In: Materials transactions, ISSN 1345-9678, E-ISSN 1347-5320, Vol. 58, no 3, p. 400-405Article in journal (Refereed)
    Abstract [en]

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

  • 12.
    Abbaszad Rafi, Abdolrahim
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Azarbaijan Shahid Madani University, Tabriz, Iran.
    Hamidi, N.
    Azarbaijan Shahid Madani University, Tabriz, Iran.
    Bashir-Hashemi, A.
    University of Alabama, Tuscaloosa, AL, United States.
    Mahkam, M.
    Azarbaijan Shahid Madani University, Tabriz, Iran.
    Photo-Switchable Nanomechanical Systems Comprising a Nanocontainer (Montmorillonite) and Light-Driven Molecular Jack (Azobenzene-Imidazolium Ionic Liquids) as Drug Delivery Systems; Synthesis, Characterization, and in Vitro Release Studies2018In: ACS Biomaterials Science & Engineering, E-ISSN 2373-9878, Vol. 4, no 1, p. 184-192Article in journal (Refereed)
    Abstract [en]

    In this work, photoresponsive nanomechanical systems were prepared through the intercalation of positively charged photoswitching molecular jacks (azobenzene ionic liquids, Azo-ILs) within montmorillonite (MMT) layers (MMT@Azo-ILs). The study shows that MMT@Azo-ILs are photosensitive and the synthesized molecular jacks could change the basal distances of MMT layers upon UV irradiation. These changes come from changes in the structure and geometry of Azo molecules (i.e., cis-trans isomerization) between clay layers upon UV irradiation. The prepared photoresponsive nanomechanical systems were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), field-emission scanning electron microscope (FE-SEM). Moreover, the in vitro release studies were performed in different conditions (upon UV irradiation and darkness) in pH 5.8 at 34 ± 1 °C, and it was found that the release rates from drug loaded MMT@Azo-ILs were higher upon UV irradiation in comparison with the release rates in darkness. According to the release studies, the prepared photoresponsive carriers might be considered as an excellent potential candidate in order to formulate smart sunscreens. © 2017 American Chemical Society.

  • 13. Abd El-Hakim, Abou El Fettouh Abd El Moneim
    et al.
    Haroun, Ahmed Abd Allah
    Rabie, Abdel Gawad Mohamed
    Ali, Gomaa Abdelgawad Mohammed
    Abdelrahim, Mohamed Yahia Marei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Helwan University, Egypt.
    Improving the mechanical and thermal properties of chlorinated poly(vinyl chloride) by incorporating modified CaCO3 nanoparticles as a filler2019In: Turkish journal of chemistry, ISSN 1300-0527, E-ISSN 1303-6130, Vol. 43, no 3, p. 750-759Article in journal (Refereed)
    Abstract [en]

    Chlorinated poly(vinyl chloride) (CPVC)/calcium carbonate nanocomposites were successfully prepared by the incorporation of calcium carbonate (CaCO3) nanoparticles into the CPVC matrix. The compatibility between the two phases was obtained by surface modification of the CaCO3 nanoparticles with stearic acid, leading to improved material performance. The effects of the addition of different amounts of CaCO3 nanoparticles to the CPVC on the thermal, mechanical, and morphological characteristics of the CPVC/CaCO3 nanocomposites were investigated. The thermal stability of the CPVC/CaCO3 nanocomposites was evaluated by thermogravimetric analysis and differential scanning calorimetry. In addition, the surface texture of the CPVC and the dispersion of the CaCO3 were evaluated using scanning electron microscopy. Important enhancements in the thermal and mechanical properties of the modified CPVC/CaCO3 nanocomposites were obtained by incorporating different amounts (2.00%, 3.75%, and 5.75%) of surface-modified CaCO3 nanoparticles within the CPVC polymer matrix. The results reveal that 3.75% of CaCO3 was the optimum amount, where the CPVC/CaCO3 nanocomposite shows the highest impact strength, the highest tensile strength, the highest thermal stability, and the lowest elongation percentage. Replacement of the commercial impact modifier used in industry with the prepared surface-modified CaCO3 nanoparticles for the development of CPVC was successfully achieved.

  • 14.
    Abdalla, Abdulbasit
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Odgren, Emilia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Biodiesel production from rape seed oil catalyzed by calcium oxide doped with lithium2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Biodiesel ses som ett av de främsta substituten för fossila bränslen, då den relativt enkelt kan appliceras i redan existerande dieselmotorer. Dagens produktion av biodiesel använder sig av homogena katalysatorer som inte återanvänds i processen, men för en mer cirkulär och i längden en billigare process ses heterogena katalysatorer som ett alternativ. Syftet med denna studie var att undersöka litium dopad kalciumoxid katalytiska egenskaper, de optimala förhållandena för reaktionen och även kinetiken för reaktionen. Den valda katalysatorn syntetiserades med kalcinering och sedan testades den katalytiska förmågan i reaktionen vid olika reaktionsförhållanden, för att finna de optimala förhållandena. Även katalysatorns fysiska egenskaper analyserades och kinetiken för reaktionen. De optimala förhållanden för transesterifieringen bestämdes till 3 h, 1:6 olja- metanolförhållande, 60°C och 5 vikts% katalysator, där 96% utbyte av biodiesel uppnåddes. Övriga utbyten från de andra försöken var betydligt lägre, vilket kan bero på icke optimala förhållanden, men även relativ dålig katalytisk förmåga. Ytarea och porstorlek konstateras vara små, vilket påverkar den katalytiska förmågan negativt. Anledningen till katalysatorns egenskaper beror huvudsakligen på tillverkningsprocessen, men även mängden litium i dopningen. Kinetiken visar en oväntad reaktionsutveckling med initialt hög koncentration FAME (Fatty acid Methylester), vilket troligen beror på felkällor.

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  • 15.
    Abdelhamid, Hani Nasser
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Assiut University, Egypt.
    Mathew, Aji P.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Cellulose-Based Materials for Water Remediation: Adsorption, Catalysis, and Antifouling2021In: Frontiers in Chemical Engineering, E-ISSN 2673-2718, Vol. 3, article id 790314Article, review/survey (Refereed)
    Abstract [en]

    Cellulose-based materials have been advanced technologies that used in water remediation. They exhibit several advantages being the most abundant biopolymer in nature, high biocompatibility, and contain several functional groups. Cellulose can be prepared in several derivatives including nanomaterials such as cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidized cellulose nanofibrils (TOCNF). The presence of functional groups such as carboxylic and hydroxyls groups can be modified or grafted with organic moieties offering extra functional groups customizing for specific applications. These functional groups ensure the capability of cellulose biopolymers to be modified with nanoparticles such as metal-organic frameworks (MOFs), graphene oxide (GO), silver (Ag) nanoparticles, and zinc oxide (ZnO) nanoparticles. Thus, they can be applied for water remediation via removing water pollutants including heavy metal ions, organic dyes, drugs, and microbial species. Cellulose-based materials can be also used for removing microorganisms being active as membranes or antibacterial agents. They can proceed into various forms such as membranes, sheets, papers, foams, aerogels, and filters. This review summarized the applications of cellulose-based materials for water remediation via methods such as adsorption, catalysis, and antifouling. The high performance of cellulose-based materials as well as their simple processing methods ensure the high potential for water remediation.

     

  • 16.
    Abdelhamid, Hani Nasser
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Assiut University, Egypt.
    Mathew, Aji P.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Cellulose-zeolitic imidazolate frameworks (CelloZIFs) for multifunctional environmental remediation: Adsorption and catalytic degradation2021In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 426, article id 131733Article in journal (Refereed)
    Abstract [en]

    The crystal growth of zeolitic imidazolate frameworks (ZIFs) on biopolymers such as cellulose is a promising method for obtaining hybrid materials that combinenatural and synthetic materials. Cellulose derivative viz. 2,2,6,6-tetramethylpiperidine-1-oxylradical (TEMPO)-mediated oxidized nanocellulose (TOCNF) was used to modulate the crystal growth of ZIF-8 (denoted as CelloZIF-8) and ZIF-L (CelloZIF-L). The synthesis procedure occurred in water at room temperature with and without NaOH. The reaction parameters such as the sequence of the chemical's addition and reactant molar ratio were investigated. The phases formed during the crystal growth were monitored. The data analysis ensured the presence of zinc hydroxide nitrate nanosheets modified TOCNF during the crystallization of CelloZIFs. These phases were converted to pure phases ofCelloZIF-8 and CelloZIF-L. The resultant CelloZIFs materials were used for the adsorption ofcarbon dioxide (CO2), metal ions, and dyes. The materials exhibited high selectivity with reasonable efficiency (100%) toward the adsorption of anionic dyes such as methyl blue (MeB). They can also be used as a catalyst for dye degradation via hydrogenation with an efficiency of 100%. CelloZIF crystals can be loaded into a filter paper for simple, fast, and selective adsorption of MeB from a dye mixture. The materials are recyclable for five cycles without significant loss of their performance. The mechanisms of adsorption and catalysis were also investigated.

  • 17.
    Abdel-Magied, Ahmed Fawzy
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery. Nuclear Materials Authority. P. O. Box 530, El Maadi, Cairo, Egypt.
    Abdelhamid, Hani Nasser
    Assiut University.
    Ashour, Radwa M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery. Nuclear Materials Authority. P. O. Box 530, El Maadi, Cairo, Egypt.
    Fu, Le
    Central South University.
    Dowaidar, Moataz
    King Fahd University of Petroleum and Minerals (KFUPM).
    Xia, Wei
    Uppsala University.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Magnetic Metal-Organic Frameworks for Efficient Removal of Cadmium(II), and Lead(II) from Aqueous Solution2022In: Journal of Environmental Chemical Engineering, ISSN 2213-3437, p. 107467-107467, article id 107467Article in journal (Refereed)
    Abstract [en]

    Efficient and convenient methods for the removal of toxic heavy metal ions especially Cd(II) and Pb(II) from aqueous solutions is of great importance due to their serious threat to public health and the ecological system. In this study, two magnetic metal-organic frameworks (namily: Fe3O4@ZIF-8, and Fe3O4@UiO-66–NH2) were synthesized, fully characterized, and applied for the adsorption of Cd(II) and Pb(II) from aqueous solutions. The adsorption efficiencies for the prepared nanocomposites are strongly dependent on the pH of the aqueous solution. The maximum adsorption capacities of Fe3O4@UiO-66–NH2, and Fe3O4@ZIF-8 at pH 6.0 were calculated to be 714.3 mg·g 1, and 370 mg·g 1 for Cd(II), respectively, and 833.3 mg·g 1, and 666.7 mg·g 1 for Pb(II), respectively. The adsorption process follows a pseudo-second-order model and fit the Langmuir isotherm model. Moreover, the thermodynamic studies revealed that the adsorption process is endothermic, and spontaneous in nature. A plausible adsorption mechanism was discussed in detail. The magnetic adsorbents: Fe3O4@ZIF-8, and Fe3O4@UiO-66–NH2 showed excellent reusability, maintaining the same efficiency for at least four consecutive cycles. These results reveal the potential use of magnetic Fe3O4@ZIF-8, and Fe3O4@UiO-66–NH2 as efficient adsorbents in removing Cd(II) and Pb(II) from aqueous solutions.

  • 18.
    Abdel-Magied, Ahmed Fawzy
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Nasser Abdelhamid, Hani
    Ashour, Radwa M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Zou, Xiaodong
    Stockholms Universitet.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Hierarchical porous zeolitic imidazolate framework nanoparticles for efficient adsorption of rare-earth elements2019In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 278, p. 175-184Article in journal (Refereed)
    Abstract [en]

    Hierarchical porous zeolitic imidazolate frameworks nanoparticles (ZIF-8 NPs) were synthesized at room temperature via a template-free approach under dynamic conditions (stirring) using water as a solvent. The ZIF-8 NPs were evaluated as adsorbents for rare earth elements (La3+, Sm3+ and Dy3+). Adsorption equilibrium was reached after 7h and high adsorption capacities were obtained for dysprosium and samarium (430.4 and 281.1 mg g(-1), respectively) and moderate adsorption capacity for lanthanum (28.8 mg g(-1)) at a pH of 7.0. The high adsorption capacitiese, as well as the high stability of ZIF-8 NPs, make the hierarchical ZIF-8 materials as an efficient adsorbent for the recovery of La3+, Sm3+ and Dy3+ from aqueous solution.

  • 19.
    Abdi, Sofia
    KTH, School of Chemical Science and Engineering (CHE).
    Preparation and process optimization of encapsulating cellulose microspheres2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Microspheres are spherically shaped particles within the size range of 1-1000 μm in diameter.

    Due to the their small size and round shape, microspheres show many advantages in various

    applications such as pharmaceuticals, composites and coatings. The microspheres can be

    customized to fit a specific application and are manufactured in various forms such as solid,

    hollow and encapsulating.

    Encapsulating cellulose microspheres have been produced in this project by the emulsionsolvent

    evaporation technique. The purpose of this study was to further investigate the

    possibility of producing encapsulating microspheres with a size range of 10-50 μm that will

    have a high encapsulation. A second purpose of this study was optimizing the emulsifier

    system for the preparation of these spheres. This has been accomplished by varying several

    process parameters such as type of emulsifiers and solvents to study the effect on morphology

    and encapsulation efficiency. The analyses of the spheres were performed with optical

    microscopy, thermal gravimetric analyzer (TGA) and scanning electron microscopy (SEM).

    The emulsifier type and concentration affected the encapsulation and size distribution but had

    no direct effect on the internal and external structure, which was multi-cellular and porous,

    respectively. The highest encapsulation in relation to average size was obtained with 0.1 v/v-

    % of the emulsifier mixture Emulsifier 1 (E1)/Emulsifier 2 (E2) (70/30 %). The solvent used

    to dissolve the polymer had a direct effect on encapsulation, a combination of Solvent 2 (S2)

    and Solvent 1 (S1) proved best for the three tested cellulose derivatives with low, medium and

    high number average molecular weight. The solvent also had an effect on the internal

    structure of the microspheres, becoming more core-shell when using the S1/S2 combination.

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  • 20.
    Abdirahman Ahmed, Fatima
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Reologistudie av vattenbaserade industrifärger2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The rheological properties of water-based paint have been studied and the parameters that were investigated were mobility, viscoelasticity, sagging and levelling. The methods that arepresented in this study can predict sagging before the paint is applied on a vertical surface. The purpose of this study is to understand how different paints behave when sprayed on a vertical surface. The main goal in this study is to develop a method that can predict sagging when the wet condition is 300 μm.

    The rheometer gave measurement data that could be graded on a scale. Every paint had a value on this graded scale. A "Shear Rate Loop Test" was used to grade the paints after a graphical analysis. The development on the graded scale gives the right information whether the paint sags or not.

    Different types of oscillation tests were performed and these tests were 3ITT, amplitude sweep and frequency sweep. Elastic and viscous behaviour were measured and they illustrated what behaviour was dominating in the paints. 28 water-based paints were analysed and the methods for these paints can predict how they flow on a vertical surface.

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  • 21.
    Abdullaeva, Oliya
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Sahalianov, Ihor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Silverå Ejneby, Malin
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Jakesova, Marie
    Brno Univ Technol, Czech Republic.
    Zozoulenko, Igor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Liin, Sara
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Neurobiology. Linköping University, Faculty of Medicine and Health Sciences.
    Glowacki, Eric
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Brno Univ Technol, Czech Republic.
    Faradaic Pixels for Precise Hydrogen Peroxide Delivery to Control M-Type Voltage-Gated Potassium Channels2022In: Advanced Science, E-ISSN 2198-3844, Vol. 9, no 3, article id 2103132Article in journal (Refereed)
    Abstract [en]

    H2O2 plays a significant role in a range of physiological processes where it performs vital tasks in redox signaling. The sensitivity of many biological pathways to H2O2 opens up a unique direction in the development of bioelectronics devices to control levels of reactive-oxygen species (ROS). Here a microfabricated ROS modulation device that relies on controlled faradaic reactions is presented. A concentric pixel arrangement of a peroxide-evolving cathode surrounded by an anode ring which decomposes the peroxide, resulting in localized peroxide delivery is reported. The conducting polymer (poly(3,4-ethylenedioxythiophene) (PEDOT), is exploited as the cathode. PEDOT selectively catalyzes the oxygen reduction reaction resulting in the production of hydrogen peroxide (H2O2). Using electrochemical and optical assays, combined with modeling, the performance of the devices is benchmarked. The concentric pixels generate tunable gradients of peroxide and oxygen concentrations. The faradaic devices are prototyped by modulating human H2O2-sensitive Kv7.2/7.3 (M-type) channels expressed in a single-cell model (Xenopus laevis oocytes). The Kv7 ion channel family is responsible for regulating neuronal excitability in the heart, brain, and smooth muscles, making it an ideal platform for faradaic ROS stimulation. The results demonstrate the potential of PEDOT to act as an H2O2 delivery system, paving the way to ROS-based organic bioelectronics.

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  • 22.
    Abdullah, Rondek
    KTH, School of Chemical Science and Engineering (CHE).
    Study of the Eutrophication of Lake Vallentuna2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Lake Vallentuna is situated 20 km north of Stockholm, in Täby and Vallentuna municipalities. It is a shallow eutrophicated lake, with a maximum depth of 6, 0 meter and the turnover time of the lake is 1, 6 years. Lake Vallentuna has two inlets, which are Ormstaån in the North and Karbyån in the South. The outlet from Lake Vallentuna is Hagbyån in the South-West. Lake Vallentuna is, due to human activities, influenced by many contaminants, for example phosphorus and nitrogen, which contribute to the eutrophication.

    The natural state of Lake Vallentuna involves a high phosphorus concentration, since it is a lake among fields dominated by clay. The increased phosphorus levels depend on various sources, such as sewage, agriculture, and storm water.

    The aim of this project is to describe the present state of the lake and to predict the future changes. This report will also give phosphorus and calcium levels determined for Lake Vallentunna. By the examination of the chemical and physical parameters we could estimate the contribution of pollutants. To assess the lake condition, an excursion was made to collect samples and perform measurements in the field. The samples were collected from twelve different sites.

    The eight parameters measured in this study are conductivity, temperature, pH, COD, chlorinity, alkalinity, calcium and total phosphorus. The assessment of the lake was based on the guidelines from the Swedish Environmental Protection Agency ”Bedömningsgrunder för miljökvalitet”. We compared the measured values with those in the guidelines. One conclusion is that the Lake is heavily eutrophicated.

    Our measurements indicate that the incoming amount of phosphorus is bigger than the outgoing amount of phosphorus, which means that the amount of phosphorus in the lake increases at the time for the measurements. However, the main source of phosphorus in the lake water is the internal contribution from the sediments, which have been accumulated during many years. The measured values of phosphorus show that the lake is eutrophicated.

    Lake Vallentuna contains big amounts of phosphorus and metal ions (see also Adam Kazi’s diploma work on metal ions in Lake Vallentuna[19] ). The reason is that the lake is situated in a very contaminated area.

  • 23.
    Abed, Samah
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Al-Kaisee, Farah
    University of Borås, Faculty of Textiles, Engineering and Business.
    Metallutvinning med fokus på zinkfrån avfallsflygaska med hjälp avsura processvatten2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sweden produces large amount of fly ash from waste combustion annually. Combustion the

    waste generates two types of ashes, bottom ash/slag, and fly ash. Bottom ash is considered to

    be more environmentally friendly and has a wide area of application such as road

    constructions on landfills. While the fly ash has high level of heavy metals and for instance

    dioxines which are harmful for the environment. This type of ash are deposited in a landfill

    and gets classified as a hazardous waste which is expensive given that the deposit fee is high.

    The fact that fly ash contains valuable metals as zinc, methods of recovering it are being

    developed such as acid leaching. This is a promising method as the leachate used are acid

    process water making the usage of the chemicals substantially lower which makes it

    financially viable.

    Waste incinerators in Sweden produce approximately 200 000 tons of fly ash annually and the

    majority of it is transfered to Norway to get treated and put on a landfill. Some waste

    management companies, e.g. Renova, are using another method called “the Bamberg method”

    where fly ash is mixed with sludge to form a cake and put in the company’s own landfill.

    The projects goal is to leach the fly ash by using acidic process water to obtain the metallic

    substance particularly zinc making it easier and cheaper to landfill the ash and also to

    optimize this method to get the most zinc out of the ash using minimum amount of the acidic

    process water (5% HCI).

    The laboratory work took place in the University of Borås. Fly ash and the acid process water

    which were used under the laboratory work was obtained from RenovaAB.

    The results shows that leaching the fly ash with acidic process water gave different release of

    zinc but was 88% at most. The variation in the results depends on a few factors such as

    amount of acidic process water, pH, time, blending time and the ashes content.

    This project took environment and access to acidic water in consideration, which optimized

    the method of using less amount of acid process water to get the most zinc as possible.

    The results shows that leaching fly ash with acid process water is cost efficient and easy way

    to recover zinc, which satisfy the goals of the project.

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  • 24. Abel, S
    et al.
    Bäbler, Matthäus
    ETH, Inst Chem & Bioengn, Dept Chem & Appl Biosci.
    Arpagaus, C
    Mazzotti, M
    Stadler, J
    Two-fraction and three-fraction continuous simulated moving bed separation of nucleosides2004In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1043, no 2, p. 201-210Article in journal (Refereed)
    Abstract [en]

     A new experimental set-up and a new simulated moving bed (SMB) operation are presented in this work. A desktop SMB unit developed as a modification of the commercial AKTA(TM) explorer working platform has been utilized for the separation of different mixtures of nucleosides. Both two fraction and three fraction SMB separations have been carried out, the latter made possible by the adoption of a new SMB configuration and operating mode (three fraction SMB, 3F-SMB, operation). Experiments demonstrate the feasibility of the 3F-SMB operation, and confirm the trends predicted based on considerations about retention of the components to be separated along the unit. 

  • 25.
    Abitbol, Tiffany
    et al.
    Institute of Materials, School of Engineering, EPFL, 1015 Lausanne, Switzerland;Bioeconomy and Health, RISE Research Institutes of Sweden, SE-114 28 Stockholm, Sweden.
    Kubat, Mikaela
    Bioeconomy and Health, RISE Research Institutes of Sweden, SE-114 28 Stockholm, Sweden.
    Brännvall, Elisabet
    Bioeconomy and Health, RISE Research Institutes of Sweden, SE-114 28 Stockholm, Sweden.
    Kotov, Nikolay
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Johnson, C. Magnus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Nizamov, Rustem
    Department of Mechanical and Materials Engineering, Faculty of Technology, University of Turku, FI-20014 Turku, Finland.
    Nyberg, Mikael
    Department of Mechanical and Materials Engineering, Faculty of Technology, University of Turku, FI-20014 Turku, Finland.
    Miettunen, Kati
    Department of Mechanical and Materials Engineering, Faculty of Technology, University of Turku, FI-20014 Turku, Finland.
    Nordgren, Niklas
    Bioeconomy and Health, RISE Research Institutes of Sweden, SE-114 28 Stockholm, Sweden.
    Stevanic, Jasna S.
    Bioeconomy and Health, RISE Research Institutes of Sweden, SE-114 28 Stockholm, Sweden.
    Guerreiro, Maria Pita
    Bioeconomy and Health, RISE Research Institutes of Sweden, SE-114 28 Stockholm, Sweden.
    Isolation of Mixed Compositions of Cellulose Nanocrystals, Microcrystalline Cellulose, and Lignin Nanoparticles from Wood Pulps2023In: ACS Omega, E-ISSN 2470-1343, Vol. 8, no 24, p. 21474-21484Article in journal (Refereed)
    Abstract [en]

    From a circular economyperspective, one-pot strategies for theisolation of cellulose nanomaterials at a high yield and with multifunctionalproperties are attractive. Here, the effects of lignin content (bleachedvs unbleached softwood kraft pulp) and sulfuric acid concentrationon the properties of crystalline lignocellulose isolates and theirfilms are explored. Hydrolysis at 58 wt % sulfuric acid resulted inboth cellulose nanocrystals (CNCs) and microcrystalline celluloseat a relatively high yield (>55%), whereas hydrolysis at 64 wt% gaveCNCs at a lower yield (<20%). CNCs from 58 wt % hydrolysis weremore polydisperse and had a higher average aspect ratio (1.5-2x),a lower surface charge (2x), and a higher shear viscosity (100-1000x).Hydrolysis of unbleached pulp additionally yielded spherical nanoparticles(NPs) that were <50 nm in diameter and identified as lignin bynanoscale Fourier transform infrared spectroscopy and IR imaging.Chiral nematic self-organization was observed in films from CNCs isolatedat 64 wt % but not from the more heterogeneous CNC qualities producedat 58 wt %. All films degraded to some extent under simulated sunlighttrials, but these effects were less pronounced in lignin-NP-containingfilms, suggesting a protective feature, but the hemicellulose contentand CNC crystallinity may be implicated as well. Finally, heterogeneousCNC compositions obtained at a high yield and with improved resourceefficiency are suggested for specific nanocellulose uses, for instance,as thickeners or reinforcing fillers, representing a step toward thedevelopment of application-tailored CNC grades.

  • 26.
    Abolhasani, Hasanali
    et al.
    Department of Materials and Polymer Engineering, Faculty of Engineering, Hakim Sabzevari University, Sabzevar 9617976487, Iran.
    Farzi, Gholamali
    Department of Materials and Polymer Engineering, Faculty of Engineering, Hakim Sabzevari University, Sabzevar 9617976487, Iran.
    Davoodi, Ali
    Materials and Metallurgical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad 917751111, Iran.
    Vakili-Azghandi, Mojtaba
    Department of Materials Engineering, Faculty of Engineering, University of Gonabad, Gonabad, 96919-57678, Iran.
    Das, Oisik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Neisiany, Rasoul Esmaeely
    Department of Materials and Polymer Engineering, Faculty of Engineering, Hakim Sabzevari University, Sabzevar 9617976487, Iran.
    Development of self-healable acrylic water-based environmental-friendly coating as an alternative to chromates coatings2023In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 176, article id 107402Article in journal (Refereed)
    Abstract [en]

    In this study, different coating systems, including solvent-based epoxy and water-based acrylic resins, were evaluated for their potential as an alternative to chromate coatings in order to avoid Cr(VI) toxic hazards. The resins were used as either pigment-free coatings or were formulated with 20-wt% zinc/aluminum pigments. The coatings were subsequently applied on galvanized ST12 steel plates and their corrosion resistance was investigated by electrochemical impedance spectroscopy (EIS) evaluations. The effect of the binder and pigment type on the impact resistance of two different polymeric coatings was also evaluated. The results of impact tests revealed completely peeled film from the substrate for epoxy coatings. However, under the same experimental conditions, very few small cracks were created in water-based acrylic coatings for both pigmented and pigment-free cases. In addition, some other parameters such as drying time and coating cost were taken into account to select a good alternative to chromate coatings. The results of this work can facilitate the introduction of an inexpensive environmentally friendly acrylic coating as a promising self-healing alternative to chromate coating.

  • 27.
    Abraham, Saron
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    High entropy oxide electrodes with ionic liquid electrolyte2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Metal-based high entropy oxides are considered promising electrode materials for use in Li- ion batteries. In this work, the most widely studied high entropy oxide Mg0.2Ni0.2Cu0.2Co0.2Zn0.2O (M-HEO) with rock salt structure was successfully synthesized by Modified Pechini synthesis, characterized by X-ray diffraction analysis, and investigated as anode active material (negative electrode) in a coin cell. M-HEO has the concept of entropy stabilisation of crystal structure in oxide system with the configurational entropy value of 1,6R which confirmed that M-HEO classified as high entropy oxide. 

    To test the electrochemical performance, full cells comprising M-HEO as anode, lithium manganese oxide (LMO) as cathode together with ionic liquid electrolyte were assembled to explore their potential for practical applications. The electrochemical cycling performance was studied by two electrochemical experiments which are three-electrode cyclic voltammetry and galvanostatic charge/discharge. The cyclic voltammetry measurement was used to determine the behaviour of the system such as potential window and scan rate, while galvanostatic charge/discharge was used to determine the performance of the battery over time by applying constant current. 

    The results demonstrate that high entropy oxide possess a stable structure. This points out the direction for the preparation of M-HEOs with stable structure and excellent performance and provides a promising candidate for anode materials for LIBs.

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  • 28.
    Abrahamsson, Filip
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Leaching of Pyrrhotite from Nickel Concentrate2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Non-oxidative acid leaching of pyrrhotite from Kevitsa’s Ni-concentrate and methods to recover by-products, have been investigated. Selective dissolution of pyrrhotite (Fe1-xS, 0<x<0.25) can enrich the content of the valuable metals, such as Ni and Co, in the final concentrate and will reduce the amount of Fe and S sent to the smelters. The pyrometallurgical smelting of leached concentrate will thus give less formation of smelter by-products in form of slag and SO2. The leaching was studied through an experimental design plan with parameter settings of  38.8% to 57.8% H2SO4 and temperatures from 60 to 100°C. The best results were obtained in experiments carried out at the lower experimental range. Leaching at 60°C with an initial acid concentration of 38.8% H2SO4 was found sufficient to selectively dissolve most of the pyrrhotite; leaving an enriched solid residue. A QEMSCAN analysis of the solid residue confirmed that most of the pyrrhotite had been dissolved and showed that pentlandite was still the main Ni-mineral. Chemical assays showed that more than 95% of the Ni, Co, and Cu remained in the final residue.

       The utilized leaching process generates by-products, in the form of large quantities of Fe2+ in solution and gaseous H2S. To recover Fe2+, crystallization of iron(ii) sulfate (FeSO4∙nH2O) from leach solution through cooling have been studied. The crystallized crystals were further dehydrated into the monohydrate (FeSO4∙H2O) through a strong sulfuric acid treatment (80%H2SO4). XRD analysis confirmed that FeSO4∙H2O was the main phase in the final crystals, and a chemical analysis showed a Fe content of about 30%, 1.5% Mg, 0.4% Ca, and 0.2% Ni.

       The possibility to leach the concentrate by circulating the acidic solution from the crystallization stage has been tested. The recirculation of the solution showed no negative effects, as the recoveries of elements and chemical assays of the final solid residue were found to be similar to the obtained assay when the concentrate was leached in a fresh solution.

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  • 29. Abtahi, Zhohreh
    et al.
    Millati, Ria
    Niklasson, Claes
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Ethanol production by Mucor indicus at high glucose and ethanol concentrations2010In: Minerva biotecnologica (Testo stampato), ISSN 1120-4826, E-ISSN 1827-160X, Vol. 22, no 3-4, p. 83-89Article in journal (Refereed)
    Abstract [en]

    Mucor indicus was cultivated under aerobic and anaerobic conditions to study its tolerance against high concentration of glucose up to 350 g/L and ethanol up to 120 g/L present in the medium. The fungus could grow well even in 350 g/L glucose and produce ethanol, but it was able to assimilate the entire glucose when its concentration was less than 200 g/L. On the other hand, M. indicus produced ethanol as the main product with yield and concentration up to 0.45 g/g and 73 g/L, respectively, while glycerol, its only major byproduct, was produced up to 24 g/L. However, the fungus was not so tolerant against exogenously added ethanol, and it could not grow with more than 40 g/L added ethanol to the culture. Under aerobic conditions, M. indicus displayed different morphology, switching from long filamentous to yeast-like growth forms by increasing initial glucose concentration. This implies that yeast-like growth can be induced by growing M. indicus at high glucose concentration. Under anaerobic conditions, only one yeast-like form was observed.

  • 30.
    Acat, Sergulan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Recovery of critical metals from secondary streams2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Mass amounts of secondary waste are generated annually from different parts of society. Most of the waste ends up either in landfills or in incineration plants. Several of these streams contain valuable metals that can be recovered [1]. In 2020, the European Commission reported the fourth list of the critical materials. The list includes a total of 30 critical materials. Several metals are critical because they are vital for developing new products. Another aspect is the risk of supply in the future, as the EU is dependent on importing critical materials from several countries. Utilizing secondary streams would be an effective way to recycle critical materials. 

    The study aimed to recover metals from secondary streams using ultrasound-assisted extraction and organic acids. The goal has been to characterize the streams to see which critical metals are present and to quantify them then. Furthermore, the goal has been to investigate the effect of ultrasound, compare the extraction with alternative processes, and provide suggestions for improvements for higher extraction for future studies. 

    This report review various metallurgical processes for recycling metals, followed by an experimental study of metal extraction from secondary streams with ultrasound assistance. Secondary streams investigated in this study were the NMC type Lithium-ion batteries (LiBs), three kinds of bottom ashes and oil shale ash from Ragn Sells AB. The effect of acid species and extraction time on metal extraction were investigated with ultrasound assistance. Inductively coupled plasma-optical emission spectrometry (ICP-OES) was used as an analysis method to characterize the ion concentrations in extracted solutions. 

    The result showed that Al, Li, Mn, Co, and Ni are interesting for metal recycling in lithium batteries. The bottom ash contained critical metals such as rare-earth elements (Ce, Dy, Er, Gd, Sc, Tb, Y) and Co, Ga, Li, V, Sb and Ru, Zn, Al, Ca, Cu, Mg, P, Ti and S. Metals such as Bi, Pd, Pt, and Rh varied between different bottom ashes. The result for the oil shale ash showed rare-earth elements such as Ce, Dy, Er, Eu, Sc, Tb, and Y and other critical metals such as Zn, Co, Cu, Ga, Li, V, Sb, Ge, Rh, Al, Ca, Mg, P, Ti, and S. 

    In ultrasound-assisted extraction, optimal leaching was achieved for a specific time for each stream and metal, respectively. In this study, the optimal leaching time for rare-earth elements was 200 s, 60 min and 30 min for bottom ash from Plant A (0-2 mm), Plant B (0-2 mm) and (0- 1 mm). Other critical metals were at 10 min and 200 s. The optimal leaching time for the oil shale ash was 30 min for rare-earth elements and 15 min for other critical metals. Both organic acids in lithium batteries showed the highest leaching at 60 min in ultrasound-assisted extraction. 

  • 31.
    Acevedo Gomez, Yasna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    On Gas Contaminants, and Bipolar Plates in Proton Exchange Membrane Fuel Cells2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The proton exchange membrane (PEM) fuel cell is an electrochemical device that converts chemical energy into electrical energy through two electrocatalytic reactions. The most common catalyst used is platinum on carbon (Pt/C), which has shown the best performance in the fuel cell until now. However, the drawback of this catalyst is that it does not tolerate impurities, and both hydrogen and oxygen may carry small amounts of impurities depending on the production sources. The purpose of this thesis is to understand the effect of two impurities that are less investigated, i.e., ammonia, which may accompany the hydrogen rich reformates from renewable sources, and nitrogen dioxide, which may come from air pollution. The mechanism of contamination and an adequate recovery method for the respective contaminant are studied. Additionally, electroplated bipolar plates with Ni-Mo and Ni-Mo-P coatings were tested as alternatives to stainless steel and carbon materials.

    The results show that ammonia not only provokes changes in the polymer membrane but also in the oxygen reduction reaction (ORR), hydrogen oxidation reaction (HOR) and catalyst ionomer in both electrodes. The extent of performance recovery after the contamination depends on the concentration used and the exposure time. In contrast, nitrogen dioxide affects the catalyst in the electrode directly; the contamination is related to side reactions that are produced on the catalyst’s surface. However, NO2 is not attached strongly to the catalyst and it is possible to restore the performance by using clean air. The time the recovery process takes depends on the potential applied and the air flow.

    Finally, the evaluation of electroplated Ni-Mo and Ni-Mo-P on stainless steel by ex situ and in situ studies shows that these coatings reduce the internal contact resistance (ICR) and the corrosion rate of the stainless steel considerably. However, the in situ experiments show that phosphorus addition to the coating does not improve the fuel cell performance; thus, the Ni-Mo alloy is found to be a promising choice for electroplating stainless steel bipolar plates.

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  • 32.
    Acevedo Gomez, Yasna
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Effect of nitrogen dioxide impurities on PEM fuel cell performanceManuscript (preprint) (Other academic)
    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.

  • 33.
    Acevedo Gomez, Yasna
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Performance recovery after contamination with nitrogen dioxide in a PEM fuel cellManuscript (preprint) (Other academic)
    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.

  • 34.
    Acevedo Gomez, Yasna
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Performance Recovery after Contamination with Nitrogen Dioxide in a PEM Fuel Cell2020In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 25, no 5, article id 1115Article in journal (Refereed)
    Abstract [en]

    While the market for 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. To investigate different recovery methods, in this study, a PEM fuel cell was contaminated with 100 ppm of NO2 at the cathode side. The possibility to recover the cell performance was 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 h 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 were suggested and compared during 7 h of operation: air recovery and air depletion. The air recovery technique was shown to be a better choice than the air depletion technique.

  • 35.
    Achenbach, Jan-Ole
    et al.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Karimi Aghda, Soheil
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Hans, Marcus
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Holzapfel, Damian M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Miljanovic, Danilo J.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Low temperature oxidation behavior of Mo2BC coatings2020In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 38, no 2, article id 023403Article in journal (Refereed)
    Abstract [en]

    Mo2BC exhibits a unique combination of high stiffness and moderate ductility, enabling the application as a protective and wear resistant coating. As the low temperature oxidation behavior of Mo2BC coatings is unexplored, direct current magnetron sputtered Mo2BC coatings were oxidized at temperatures ranging from 500 to 100 degrees C for up to 28 days. Time-of-flight elastic recoil detection analysis reveals that the onset of oxidation takes place at approximately 300 degrees C as a significant increase in the O content was observed. Crystalline oxide scales containing orthorhombic MoO3 were identified after oxidation for 15 min at 500 degrees C and 10 days at 200 degrees C. Isothermal oxidation at 200 and 100 degrees C exhibits oxide scale thicknesses of 401 +/- 33 and 22 +/- 10 nm after 14 days. Oxidation for 28 days at 100 degrees C exhibits an oxide scale thickness of 13 +/- 3 nm, which is comparable to the aforementioned oxide scale thickness after oxidation for 14 days at 100 degrees C. Based on the combination of mechanical properties and the here reported low temperature oxidation behavior, Mo2BC coatings qualify for applications in solid wood machining and low temperature forming processes at temperatures close to 100 degrees C or below.

  • 36.
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Group of Forest Products2018In: Presented at Symposium "Perspectives in Renewables", 4-5 June 2018, BOKU Vienna, Austria, 2018Conference paper (Other academic)
  • 37.
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Utilisation of renewable biomass and waste materials in furniture and construction composites2018Conference paper (Other academic)
  • 38.
    Adamopoulos, Stergios
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Ahmed, Sheikh Ali
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Lankveld, Chiel
    Accsys Group, Netherlands.
    Acoustic properties of acetylated wood under different humid conditions and its relevance for musical instruments2018In: Proceedings of the 9th European Conference on Wood Modification 2018, Arnhem, The Netherlands / [ed] Jos Creemers, Thomas Houben, Bôke Tjeerdsma, Holger Militz and Brigitte Junge, The Netherlands: Practicum , 2018, p. 236-243Conference paper (Refereed)
    Abstract [en]

    In musical instrument making, less expensive wood species and materials with good characteristics and acoustical properties can provide potentials to find alternatives to the traditional exotic wood species used today. Modified wood could be such a choice if shows similar sound characteristics to wood coming from endangered and expensive tropical species with problematic commercial availability. In musical instruments, the overall functionality depends on the contribution of wood to different material performance indexes like sound radiation coefficient (R), characteristic impedance (z) and acoustic conversion efficiency (ACE). In this study, the performance indexes were measured for acetylated beech, maple and radiata pine and compared with these obtained for the reference wood materials maple, mahogany, alder and ash. A non-destructive free-free flexural vibration test method was used at constant temperature (20oC) but in different humid conditions- dry (35% RH), standard (65% RH) and wet (85% RH). Dimensional changes in the different humid conditions were also taken in account. Acetylated wood showed lower EMC with higher dimensional stability at each humidity level as compared with the reference wood materials. These properties are considered important factors for making quality musical instruments. Based on the acoustical properties, acetylated wood materials, especially radiata pine, showed good potential for use for musical instruments where specific characteristics of sound are required. However, the other types of acetylated wood can also be used for specific musical instruments.

  • 39. Adamus, Grazyna
    et al.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Höglund, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Kowalczuk, Marek
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    MALDI-TOF MS Reveals the Molecular Level Structures of Different Hydrophilic-Hydrophobic Polyether-esters2009In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 10, no 6, p. 1540-1546Article in journal (Refereed)
    Abstract [en]

    Multi- and triblock copolymers based on 1,5-dioxepan-2-one/epsilon-caprolactone (DXO/CL) were investigated by MALDI-TOF MS to determine the influence of copolymer composition and architecture on the molecular structures at the individual chain level. The copolymer compositions, average block lengths, and molecular weights were determined by H-1 and C-13 NMR and by SEC, respectively. The structures of polyether-ester oligomers (linear, cyclic) as well as the chemical structures of their end groups were established on the basis of their MALDI-TOF mass spectra. The mass spectrum of PDXO homopolymer was relatively simple, however, complex mass spectra were obtained in the case of multi- and triblock copolymers and the mass spectra clearly discerned the molecular level effect of copolymer composition and copolymer type.

  • 40.
    Adan, Saida
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Winberg: Behavioral Neuroendocrinology.
    Applying automatic operant boxes (“Skinner boxes”) for studies on behavioural flexibility in zebrafish (Danio rerio) 2020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The most successful and widely used animal models in neuroscience are rats and mice, which has been vital for the understanding of the human brain. Another model that has become more prominent during recent years is the zebrafish (Danio rerio). Due to its well-elaborated visual system and learning of aversive events, the zebrafish has become a suitable model for learning and memorizing. In this paper, the relationship between coping styles and learning in different zebrafish strains has been studied by using automatic operant boxes. The strains that were compared are the Tupfel Long Fin (TL). offspring of wild-caught zebrafish (WT) and the Spiegel danio (Spd). The results from the novel tank diving test suggest that there is a difference in coping style depending on the strain of zebrafish. The TL was characterized as a reactive (shy) fish as it had the longest cumulative duration time at the bottom of the tank. The Spd was characterized as a proactive (bold) fish as it had the longest cumulative duration time at the top of the tank. While, the WT characterized as a reactive fish as it exhibited the longest time not moving at all in the tank, indicating a high-stress response profile. An automatic operant box was used to study learning in the different strains. The purpose of the script used was for the fish to associate the feeder mechanism noise and the white light feeder with a food reward. However, no tendency of learning could be observed for any of the strains. 

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  • 41.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Synthesis of reactive soybean oils for use as a biobased thermoset resins in structural natural fiber composites2009In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 115, no 6, p. 3137-3145Article in journal (Refereed)
    Abstract [en]

    Biobased thermosets resins were synthesized by functionalizing the triglycerides of epoxidized soybean oil with methacrylic acid, acetyl anhydride, and methacrylic anhydride. The obtained resins were characterized with FTIR, 1H-NMR, and 13C-NMR spectroscopy to confirm the functionalization reactions and the extent of epoxy conversion. The viscosities of the methacrylated soybean oil resins were also measured for the purpose of being used as a matrix in composite applications. The cross-linking capability was estimated by UV and thermally initiated curing experiments, and by DSC analysis regarding the degree of crosslinking. The modifications were successful because up to 97% conversion of epoxy group were achieved leaving only 2.2% of unreacted epoxy groups, which was confirmed by 1H-NMR. The 13C-NMR confirms the ratio of acetate to methacrylate methyl group to be 1 : 1. The viscosities of the methacrylated soybean oil (MSO) and methacrylic anhydride modified soybean oil (MMSO) were 0.2 and 0.48 Pas, respectively, which indicates that they can be used in resin transfer molding process.

  • 42.
    Adler, Anneli
    et al.
    Swedish University of Agricultural Sciences.
    Kumaniaev, Ivan
    Stockholm University.
    Karacic, Almir
    Swedish University of Agricultural Sciences.
    Baddigam, Kiran Reddy
    Stockholm University.
    Hanes, Rebecca J.
    Strategic Energy Analysis Center, USA; Center for Bioenergy Innovation, USA.
    Subbotina, Elena
    Stockholm University.
    Bartling, Andrew W.
    Center for Bioenergy Innovation, USA; Catalytic Carbon Transformation and Scale-up Center, USA.
    Huertas-Alonso, Alberto J.
    Stockholm University; University of Castilla-La Mancha, Spain.
    Moreno, Andres
    University of Castilla-La Mancha, Spain.
    Håkansson, Helena
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Mathew, Aji P.
    Stockholm University.
    Beckham, Gregg T.
    Center for Bioenergy Innovation, USA; Renewable Resources and Enabling Sciences Center; USA.
    Samec, Joseph S.M.
    Stockholm University; Chulalongkorn University, Thailand .
    Lignin-first biorefining of Nordic poplar to produce cellulose fibers could displace cotton production on agricultural lands2022In: Joule, E-ISSN 2542-4351, Vol. 6, no 8, p. 1845-1858Article in journal (Refereed)
    Abstract [en]

    Here, we show that lignin-first biorefining of poplar can enable the production of dissolving cellulose pulp that can produce regenerated cellulose, which could substitute cotton. These results in turn indicate that agricultural land dedicated to cotton could be reclaimed for food production by extending poplar plantations to produce textile fibers. Based on climate-adapted poplar clones capable of growth on marginal lands in the Nordic region, we estimate an environmentally sustainable annual biomass production of ∼11 tonnes/ha. At scale, lignin-first biorefining of this poplar could annually generate 2.4 tonnes/ha of dissolving pulp for textiles and 1.1 m3 biofuels. Life cycle assessment indicates that, relative to cotton production, this approach could substantially reduce water consumption and identifies certain areas for further improvement. Overall, this work highlights a new value chain to reduce the environmental footprint of textiles, chemicals, and biofuels while enabling land reclamation and water savings from cotton back to food production.

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  • 43.
    Adolfsson, Karin H.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Huang, Ping
    Department of Chemistry – Ångström Laboratory, Uppsala University, Box 523, Uppsala, 751 20, Sweden, Box 523.
    Golda-Cepa, Monika
    Faculty of Chemistry, Jagiellonian Universityul, Krakow, 30–387, Poland.
    Xu, Huan
    School of Materials Science and Physics, China University of Mining and Technology, Xuzhou, 221116, P. R. China.
    Kotarba, Andrzej
    Faculty of Chemistry, Jagiellonian Universityul, Krakow, 30–387, Poland.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Scavenging of DPPH by Persistent Free Radicals in Carbonized Particles2023In: Advanced Sustainable Systems, E-ISSN 2366-7486, Vol. 7, no 3, article id 2200425Article in journal (Refereed)
    Abstract [en]

    Persistent free radicals (PFR) in carbonized particles may play a role in degradation of environmental compounds. The influence of PFR is evaluated in various carbonized particles on their radical scavenging efficiency upon the common radical indicator 2-2-diphenyl-1-picrylhydrazyl (DPPH). Carbonized particles are derived by hydrothermal carbonization of glucose (C-W) or glucose and urea (NC-W) and ionothermal carbonization of glucose and urea ionic liquid (IL) (NC-IL). The carbonized materials contain OH/COOH, C=C, and C-O functionalities. The addition of urea introduces NH/NH2 functionalities. The content of polar surface groups is lower in IL-processed NC-IL. The scavenging ability, measured as DPPH UV–vis absorption decline, increases with concentration and time for all particles, while the efficiency changes are in the order of C-W > NC-W > NC-IL. Electron paramagnetic resonance analysis reveals similar radical concentration in all carbonized materials studied. The difference in efficiency is, thus, not directly related to the PFR concentration but rather to the type of PFR, surface functionalities and/or scavenging mechanism. According to the g-values, radicals in these particles are carbon-centered. The minor variation in g-values suggests interactions between the radicals and their environmental functional groups. This provides insights into the influence of PFR in carbonized materials on their radical scavenging efficiency.

  • 44.
    Adolfsson, Karin H.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Lin, Chia-feng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Microwave Assisted Hydrothermal Carbonization and Solid State Postmodification of Carbonized Polypropylene2018In: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 6, no 8, p. 11105-11114Article in journal (Refereed)
    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.

  • 45.
    Adolfsson, Karin H.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Sjöberg, I.
    Höglund, O. V.
    Wattle, O.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    In Vivo Versus In Vitro Degradation of a 3D Printed Resorbable Device for Ligation of Vascular Tissue in Horses2021In: Macromolecular Bioscience, ISSN 1616-5187, E-ISSN 1616-5195, Vol. 21, no 10, article id 2100164Article in journal (Refereed)
    Abstract [en]

    A resorbable 3D printed polydioxanone (PDO) device is manufactured to facilitate ligation of vascular tissue during surgery. The device must provide sufficient mechanical performance throughout the healing period. Therefore, degradation and mechanical performance of the device are investigated as a function of in vivo and in vitro aging. During aging the PDO device released cyclic and linear water-soluble products. In vivo aging resulted in higher relative number of linear oligomers in comparison to in vitro aging. A major loss of mechanical performance is observed after only 10 days in vivo and the Young’s modulus (E) and tensile strength at break (σb) decreased by 28% and 54%, respectively. This is in contrast to in vitro aging, where no loss of mechanical properties is observed during the same period. The in vivo aged devices exhibit clear holes in the matrices after 28 days, while apparent cracks are observed first after 140 days in vitro. These results highlight the sensitivity of the degradation process of resorbable devices with regards to the interactions of the device with the surrounding environment (tissues) and demonstrate the importance of in vivo testing as compliment to in vitro testing before clinical use of devices.

  • 46.
    af Ugglas, Samuel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Waste diagnostic - A caste study of a company’s waste management2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This case study of the waste management at a pharmaceutical company investigates the current situation and possible improvements for future work in terms of amount of waste generated, treatment methods and economy. The scope of the project was to assess all current waste streams from the everyday activities and find potential areas for improvement. Chemical/solvent waste have not been investigated thoroughly because of the complexity to make changes within the manufacturing processes. Waste generated during demolition and construction by external contractors have been excluded since it is not a part of the business as usual.

    The company has set the goal to decrease greenhouse gas emissions by 20% and waste generated by 15% and to achieve these goals the waste diagnostic project have been initiated. Waste reports and guided tours at each department have been compiled to assess and map out all waste streams at the site. The waste management hierarchy has been used as a tool together with performance measurements to evaluate current situation and with examples from literature, other sites and industries recommendations have been made. The waste management hierarchy is a tool used to prioritize waste management to reach a circular economy, with landfill at the bottom and reduction/reuse at the top of the hierarchy the current status of a company can be assessed and also what areas that have to be improved in order to climb the hierarchy. The company shows a good environmental performance today and comply with internal standards, the waste metric scoring calculation results in a value of, , 464 which corresponds to energy recovery level of the waste management hierarchy.

    An ISO certificate ensures customers that a product or service meet the standards the customer have. There are ISO standards within many different areas and ISO 14001 applies to environmental management which the company is not certified with. The company comply with the internal standards but an ISO certificate would result in extra credibility. Some of the recommendations to the site includes a waste management communication program to engage employees, reuse of disposable pallets, drying of wastewater sludge and installation of paper shredder to reduce costs related to classified documents.

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  • 47.
    Afewerki, Samson
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Alimohammadzadeh, Rana
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Henshaw Osong, Sinke
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Tai, Cheuk-Wai
    The Arrhenius Laboratory, Stockholm University.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Eco-friendly design for scalable direct fabrication of nanocelluloseManuscript (preprint) (Other academic)
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  • 48.
    Afewerki, Samson
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Cooperative Lewis Acids and Aminocatalysis2017In: Chiral Lewis Acids in Organic Synthesis / [ed] J. Mlynarski, Wiley-Blackwell , 2017, p. 345-374Chapter in book (Refereed)
    Abstract [en]

    This chapter describes the cooperative strategy of combining metal catalyst activation with aminocatalysis, with a focus on the metal acting as a Lewis acid catalyst. It gives examples where the metal catalyst promotes the reactivity of different substrates by the formation of reactive intermediates. These intermediates can act either as electrophiles or nucleophiles, which in turn can couple with nucleophilic enamine or electrophilic iminium intermediates formed between the carbonyl compounds and aminocatalyst. The chemical transformation ensues via the merging of the enamine and π‐allyl‐Pd complex via asymmetric counteranion‐direct catalysis (ACDC). Subsequently, several groups reported different co‐catalytic systems and chemical strategies for the α‐allylic alkylation of aldehydes and ketones. Cordova and coworkers reported the first example where iminium activation catalysis is combined with metal catalyst activation cooperatively. The stratagem was demonstrated for the catalytic enantioselective conjugate silyl addition to α,β‐unsaturated aldehydes.

  • 49.
    Agalo, Faith
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Synthesis of Insulin-Regulated Aminopeptidase (IRAP) inhibitors2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The need for alternative cognitive enhancers has risen due to the fact that clinical trial results of the drugs currently approved for treating these disorders have not been satisfactory.

    IRAP has become a possible drug target for treating cognitive impairment brought about by Alzheimer’s disease, head trauma or cerebral ischemia, among others. This came after the revelation that Angiotensin IV enhances memory and learning. Angiotensin IV, the endogenous ligand of IRAP has been structurally modified with the aim of producing potent IRAP inhibitors. However, the peptidic nature of these inhibitors restricts their use; they are not likely to cross the blood brain barrier.

    Other strategies for generating IRAP inhibitors have been through structure-based design and receptor based virtual screening. These drug-like molecules have exhibited positive results in animal studies.

    IRAP inhibitors have been identified via a HTS of 10500 low-molecular weight compounds to give the hit based on a spirooxindole dihydroquinazolinone scaffold, with an IC50 value of 1.5 µM. In this project, some analogues to this hit compound have successfully been synthesized using a known method, whereas others have been synthesized after additional method development.

    The application of the developed method was found to be limited, because poor yield was obtained when a compound with an electron withdrawing substituent on the aniline was synthesized. As a result of this, modification of this method may be required or new methods may have to be developed to synthesize these types of analogues.

    Inhibition capability of 5 new spirooxindole dihydroquinazolinones was tested through a biochemical assay. Compound 6e emerged as the most potent inhibitor in the series, with an IC50 value of 0.2 µM. This compound will now serve as a lead compound and should be used as a starting point for future optimization in order to generate more potent IRAP inhibitors.

     

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  • 50.
    Agarwal, Ayush
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Experimental study of high-pressure fluidized bed gasification of biomass at pilot scale: A proof of concept2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Climate change is real. Rising world population and increasing energy demands are taking a toll on the planet. Moving towards a greener, cooler and sustainable future, there is a need for cleaner, efficient, and reliable sources of energy, and biomass is one of them. This thesis work performed at KTH Royal Institute of Technology attempts to contribute to this pressing need. High-pressure biomass gasification technology is an important process intensification step. However, it is not well investigated yet. This work attempts to understand the performance and pave the pathway for future studies.

    Experiments were performed using olivine, magnesite, and silica sand as bed material. Grot and birch were tested as fuel. The experiments were carried out in a 75 KWfuel bubbling fluidized bed gasifier at 20 bar, using Steam/Oxygen as a gasifying agent. Produced gas composition, tar production, and carbon conversion efficiency were examined. Olivine and magnesite showed good resistance against attrition and agglomeration. Stable bed temperature with no signs of defluidization or sintering were observed during the experiments. Silica sand cannot be used as a bed material with grot due to its high ash content. However, mild agglomeration was also observed with the birch feedstock. Carbon dioxide in the produced gas increased with increase in pressure, whereas, carbon monoxide decreased with increase in pressure. Olivine showed excellent reduction properties for tars lighter than naphthalene, whereas, magnesite performed best for overall tar reduction for grot. It was observed that fuel feeding is a big challenge for running operation at high pressure.

    These tests at 20 bar were an intermediate step to validate BFB biomass gasification at 40 bar. It would be interesting to study the changes in gas composition, tar, and char formation to evaluate the performance related to carbon conversion efficiency, produced gas composition, and tar production for different bed material at 40 bar.

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