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  • 1. Aaditya, V. B.
    et al.
    Bharathesh, Badada Math
    KTH.
    Harshitha, R.
    Chaluvaraju, B. V.
    Raghavendra, U. P.
    Murugendrappa, M. V.
    Study of dielectric properties of polypyrrole/titanium dioxide and polypyrrole/titanium dioxide-MWCNT nano composites2018In: Journal of materials science. Materials in electronics, ISSN 0957-4522, E-ISSN 1573-482X, Vol. 29, no 4, p. 2848-2859Article in journal (Refereed)
    Abstract [en]

    The polypyrrole/titanium dioxide nano composites and polypyrrole/titanium dioxide-MWCNT nano composites were synthesized by chemical polymerization technique in the presence of an ammonium persulphate (oxidizing agent). Different concentrations viz. 15, 30, 45 and 60 wt% of titanium dioxide (TiO2) as well as mixture of TiO2-MWCNT in polypyrrole (PPy) respectively were used in the present study. The nano composites have almost spherical type shaped particles which have cluster formation as confirmed from SEM photos. The XRD graphs reveal that the PPy/TiO2 (PT) nano composites have shown the semi-crystalline nature and also, the graphs indicate the changeover of the structure of PPy/TiO2-MWCNT (PTM) nano composites from amorphous to semi-crystalline nature. From the FTIR figures, shift in wavenumber towards lower side is noticed in the case of PT and PTM nano composites when compared to PPy. The dielectric properties such as dielectric constant, dielectric loss and tangent loss have shown good behavior. This reveals that, the TiO2 as well as mixture of TiO2-MWCNT particles have shown strong dependence on PPy and helps to form good composites. So, the nano composites are good dielectric materials.

  • 2.
    Abedin, Ahmad
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Zurauskaite, Laura
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Asadollahi, Ali
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Garidis, Konstantinos
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Jayakumar, Ganesh
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Malm, B. Gunnar
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Hellström, Per-Erik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems.
    Östling, Mikael
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Germanium on Insulator Fabrication for Monolithic 3-D Integration2018In: IEEE Journal of the Electron Devices Society, E-ISSN 2168-6734, Vol. 6, no 1, p. 588-593Article in journal (Refereed)
    Abstract [en]

    A low temperature (T-max = 350 degrees C) process for Germanium (Ge) on insulator (GOI) substrate fabrication with thicknesses of less than 25 nm is reported in this paper. The process is based on a single step epitaxial growth of a Ge/SiGe/Ge stack on Si, room temperature wafer bonding and an etch-back process using Si0.5Ge0.5 as an etch-stop layer. GOI substrates with surface roughness below 0.5 nm, 0.15% tensile strain, thickness nonuniformity of less than 3 nm and residual p-type doping of less than 1016 cm(-3) were fabricated. Ge pFETs are fabricated (T-max = 600 degrees C) on the GOI wafer with 70% yield. The devices exhibit a negative threshold voltage of -0.18 V and 60% higher mobility than the SOI pFET reference devices.

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  • 3.
    Adhikari, Arindam
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Pani, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Deidinaitei, Andra
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Blomberg, Eva
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry.
    Electrochemical behavior and anticorrosion properties of modified polyaniline dispersed in polyvinylacetate coating on carbon steel2008In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 53, no 12, p. 4239-4247Article in journal (Refereed)
    Abstract [en]

    Conducting polyaniline (Pani) was prepared in the presence of methane sulfonic acid (MeSA) as dopant by chemical oxidative polymerization. The Pani-MeSA polymer was characterized by FT-IR, UV-vis, X-ray diffraction (XRD) and impedance spectroscopy. The polyrner was dispersed in polyvinylacetate and coated oil carbon steel samples by a dipping method. The electrochemical behavior and anticorrosion properties of the coating, oil carbon steel in 3% NaCl were investigated using Open-circuit Potential (OCP) versus time of exposure, and electrochemical techniques including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and cyclic voltammetry (CV). During initial exposure, the OCP dropped about 0.35 V and the interfacial resistance increased several times, indicating I certain reduction of the polymer and oxidation of the steel surface. Later the OCP shifted to the noble direction and remained at a stable value during the exposure up to 60 days. The EIS monitoring also revealed the initial change and later stabilization of the coating. The stable high OCP and low coating impedance Suggest that the conducting polymer maintains its oxidative state and provides corrosion protection for carbon steel through out the investigated period. The polarization curves and CV show that the conducting polymer coating induces a passive-like behavior and greatly reduces the corrosion of carbon steel.

  • 4.
    Adorno Lopes, Denise
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Engineering.
    Wilson, T. L.
    Univ South Carolina, Columbia, SC 29208 USA..
    Kocevski, V.
    Univ South Carolina, Columbia, SC 29208 USA..
    Moore, E. E.
    Univ South Carolina, Columbia, SC 29208 USA..
    Besmann, T. M.
    Univ South Carolina, Columbia, SC 29208 USA..
    Wood, E. Sooby
    Univ Texas San Antonio, San Antonio, TX USA..
    White, J. T.
    Los Alamos Natl Lab, Los Alamos, NM USA..
    Nelson, A. T.
    Los Alamos Natl Lab, Los Alamos, NM USA..
    Middleburgh, S. C.
    Westinghouse Elect Sweden AB, Vasteras, Sweden.;Bangor Univ, Nucl Futures Inst, Bangor LL57 1UT, Gwynedd, Wales..
    Claisse, Antoine
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Engineering.
    Experimental and computational assessment of U-Si-N ternary phases2019In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 516, p. 194-201Article in journal (Refereed)
    Abstract [en]

    Uranium nitride-silicide composites are being considered as a high-density and high thermal conductivity fuel option for light water reactors. During development, chemical interactions were observed near the silicide melting point which resulted in formation of an unknown U-Si-N ternary phase. In the present work, U-Si-N composite samples were produced by arc-melting U3Si2 under an argon-nitrogen atmosphere to form the ternary phase. The resulting samples were characterized by SEM/EDS-EPMA and XRD, and demonstrated an equilibrium between U3Si2, UN, USi and a U-Si-N phase with a distinct crystallographic structure. Rietveld refinement of the ternary structure was performed, considering the ternary structures existent in the analogue U-Si-C system, and a good fit was obtained for the hexagonal U(20)Si(16)N(3 )phase. DFT + U calculations were performed in parallel to evaluate the thermodynamic and dynamic stability of the ternaries U20Si16N3 and U3Si2N2. The calculated enthalpy of formation and phonon dispersion support the existence of stable U20Si16N3 and U3Si2N2, although some soft modes in the U(20)Si(16)N(3)( )phase phonons are observed. The results presented here thus demonstrate the occurrence of at least one ternary phase in the U-Si-N system.

  • 5.
    Afrasiabi, Roodabeh
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Jokilaakso, Nima
    KTH, School of Biotechnology (BIO), Protein Technology.
    Schmidt, Torsten
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Björk, P.
    Eriksson Karlström, Amelie
    KTH, School of Biotechnology (BIO), Protein Technology.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Effect of microwave-assisted silanization on sensing properties of silicon nanoribbon FETs2015In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 209, p. 586-595Article in journal (Refereed)
    Abstract [en]

    An important concern with using silicon nanoribbon field-effect transistors (SiNR FET) for ion-sensing is the pH-response of the gate oxide surface. Depending on the application of the FET sensor, this response has to be chemically manipulated. Thus in silicon oxide-gated pH-sensors with integrated sensor and reference FETS, a surface with high pH-sensitivity, compared to the bare gate oxide, is required in the sensor FETs (SEFET), whereas in the reference FETs (REFET) the surface has to be relatively pH-insensitive. In order to control the sensitivity and chemistry of the oxide surface of the nanoribbons, a silanization reagent with a functional group is often self-assembled on the SiNR surface. Choice of a silanization reaction that results in a self-assembled layer on a silicon oxide surface has been studied extensively over the past decades. However, the effect of various self-assembled layers such as monolayers or mixed layers on the electrical response of SiNR FETs in aqueous solution needs to be exploited further, especially for future integrated SEFET/REFET systems. In this work, we have performed a comprehensive study on 3-aminopropyltriethoxysilane (APTES) silanization of silicon oxide surfaces using microwave (MW) heating as a new biocompatible route to conventional methods. A set of complementary surface characterization techniques (ellipsometry, AFM and ATR-FTIR) was used to analyze the properties of the APTES layer deposited on the silicon surface. We have found that a uniform monolayer can be achieved within 10 min by heating the silanization solution to 75 degrees C using MW heating. Furthermore, electrical measurements suggest that little change in device performance is observed after exposure to MW irradiation. Real-time pH measurements indicate that a uniform APTES monolayer not only reduces the pH sensitivity of SiNR FET by passivating the surface silanol groups, but also makes the device less sensitive to cation concentration in the background electrolyte. Our silanization route proves promising for future chemical surface modification of on-chip REFETs.

  • 6.
    Afzal, Muhammad
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Raza, R.
    Du, S.
    Lima, R.B.d
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Hubei Univ, Fac Phys & Elect Technol, Hubei Collaborat Innovat Ctr Adv Organ Chem Mat, Wuhan 430062, Peoples R China.
    Synthesis of Ba0.3Ca0.7Co0.8Fe0.2O3-δ composite material as novel catalytic cathode for ceria-carbonate electrolyte fuel cells2015In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 178, p. 385-391Article in journal (Refereed)
    Abstract [en]

    This work reports a new composite BaxCa1-xCoyFe1-yO3-delta (BCCF) cathode material for advanced and low temperature solid oxide fuel cells (SOFCs). The BCCF-based composite material was synthesized by sol gel method and investigated as a catalytic cathode for low temperature (LT) SOFCs. XRD analysis of the as-prepared material revealed the dominating BCCF perovskite structure as the main phase accompanied with cobalt and calcium oxides as the secondary phases resulting into an overall composite structure. Structure and morphology of the sample was observed by Field Emission Scanning Electron Microscope (FE-SEM). In particular, the Ba0.3Ca0.7Co0.8Fe0.2O3-delta (BCCF37) showed a maximum conductivity of 143 S cm(-1) in air at 550 degrees C measured by DC 4 probe method. The BCCF at the optimized composition exhibited much higher electrical conductivities than the commercial Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) perovskite cathode material. A maximum power density of 325 mW cm(-2) at 550 degrees C is achieved for the ceria-carbonate electrolyte fuel cell with BCCF37 as the cathode material.

  • 7.
    Afzal, Muhammad
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Wang, Baoyuan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Xia, Chen
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Zhang, Wei
    He, Yunjuan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Jayasuriya, Jeevan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Zhu, Binzhu
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fabrication of novel electrolyte-layer free fuel cell with semi-ionic conductor (Ba0.5Sr0.5Co0.8Fe0.2O3-delta- Sm0.2Ce0.8O1.9) and Schottky barrier2016In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 328, p. 136-142Article in journal (Refereed)
    Abstract [en]

    Perovskite Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) is synthesized via a chemical co-precipitation technique for a low temperature solid oxide fuel cell (LTSOFC) (300-600 degrees C) and electrolyte-layer free fuel cell (EFFC) in a comprehensive study. The EFFC with a homogeneous mixture of samarium doped ceria (SDC): BSCF (60%:40% by weight) which is rather similar to the cathode (SDC: BSCF in 50%:50% by weight) used for a three layer SOFC demonstrates peak power densities up to 655 mW/cm(2), while a three layer (anode/ electrolyte/cathode) SOFC has reached only 425 mW/cm(2) at 550 degrees C. Chemical phase, crystal structure and morphology of the as-prepared sample are characterized by X-ray diffraction and field emission scanning electron microscopy coupled with energy dispersive spectroscopy. The electrochemical performances of 3-layer SOFC and EFFC are studied by electrochemical impedance spectroscopy (EIS). As-prepared BSCF has exhibited a maximum conductivity above 300 S/cm at 550 degrees C. High performance of the EFFC device corresponds to a balanced combination between ionic and electronic (holes) conduction characteristic. The Schottky barrier prevents the EFFC from the electronic short circuiting problem which also enhances power output. The results provide a new way to produce highly effective cathode materials for LTSOFC and semiconductor designs for EFFC functions using a semiconducting-ionic material.

  • 8. Ai, S. -Y
    et al.
    Long, M. -J
    Zhang, M. -Y
    Chen, D. -F
    Liu, P.
    Dong, Zhihua
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Properties.
    High-temperature strength of l245mb slab and elastic properties of iron matrix2019In: Kang T'ieh/Iron and Steel, ISSN 0449-749X, Vol. 54, no 8, p. 194-201Article in journal (Refereed)
    Abstract [en]

    It‘s important to understand the evolution of high-temperature properties of slabs from the microscopic structure and the macroscopic structure, which is of great significance to the performance and quality control of slabs. The variation of the high-temperature strength of the L245MB slab with the temperature was measured by the hot tensile test technique with the Gleeble system. For the Fe matrix phase, which was under different crystal structures and magnetic states, the EMTO first-principles method was used to calculate the bulk modulus B, the single-crystal elastic constants c’ and c44, the polymorphic Young's modulus E, and the evolution of the system magnetic moment μ with temperature. The results showed that the cooling rate had little effect on the high-temperature strength evolution of the slab. The high-temperature strength took a transition near Ae3 and TC temperature, with a "platform" presented, where the average evolution rate of tensile strength was 0.008 Mpa/℃ and the yield strength was 0.076 Mpa/℃. The thermoplasticity of the slab had a different degree of decline in the temperature range of TC~Ae3, and the reduction of the area was the smallest at about 800℃, which was 59.02%~62.79%. The temperature range of ductility trough increased with the cooling rate increasing, and the surface temperature of the straightening zone should be controlled above 850 ℃ to avoid the crack generation. The elastic properties of the Fe matrix phase changed with the change of the magnetic state and the crystal structure. The transformation of the magnetic state had a greater influence on c’, c44, E, and the transformation of the crystal structure had a greater influence on B. During the transformation of FM to PM, c’ and E decreased by 64.09% and 10.33%, c44 increased by 57.82%, and B decreased by 34.38% with the change of bcc to fcc structure. The relationship between the evolution of single crystal elastic constant c’, polycrystalline Young's modulus E and the high-temperature strength of the slab were analyzed. It provides an idea for analyzing the macroscopic performance of the slab from the microstructural parameters of the crystal structure, which is a basis for the research and application of the first principles method in the high-temperature mechanical properties of steel materials. 

  • 9.
    Ajpi Condori, Cesario
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. UMSA-University.
    Leiva, Naviana
    Lundblad, Anders
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Cabrera, Saul
    Synthesis and spectroscopic characterization of Fe3+-BDC metal organic framework as material for lithium ion batteries2023In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1272, p. 134127-134127, article id 134127Article in journal (Refereed)
    Abstract [en]

    This work presents synthesis and spectroscopic characterization of a new metal-organic framework (MOF). The compound Fe-BDC-DMF was synthetized by the solvothermal method and prepared via a reaction between FeCl3.6H2O and benzene-1,4-dicarboxylic acid (H2BDC) or terephthalic acid using N,N-dimethylformamide (DMF) as solvent. The powder was characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and infrared spectroscopy (IR) analysis. The electrochemical properties were investigated in a typical lithium-ion battery electrolyte by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charging and discharging. The synthetized Fe-BDC-DMF metal-organic framework (MOF) contains a mixture of three phases, identified by PXRD as: MOF-235, and MIL-53(Fe) monoclinic with C2/c and P21/c space groups. The structure of the Fe-BDC is built up from Fe3+ ions, terephalates (BDC) bridges and in-situ-generated DMF ligands. The electrochemical measurements conducted in the potential range of 0.5–3.5 V vs. Li+/Li0 show the voltage profiles of Fe-BDC and a plateau capacity of around 175 mAh/g.

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  • 10.
    Ajpi Condori, Cesario
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. UMSA Univ Mayor San Andres, IIQ Chem Res Inst, Dept Inorgan Chem & Mat Sci Adv Mat, La Paz 303, Bolivia..
    Leiva, Naviana
    UMSA Univ Mayor San Andres, IIQ Chem Res Inst, Dept Inorgan Chem & Mat Sci Adv Mat, La Paz 303, Bolivia..
    Vargas, Max
    UMSA Univ Mayor San Andres, IIQ Chem Res Inst, Dept Inorgan Chem & Mat Sci Adv Mat, La Paz 303, Bolivia..
    Lundblad, Anders
    RISE, Res Inst, Div Safety & Transport Elect, SE-50462 Borås, Sweden..
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Cabrera, Saul
    UMSA Univ Mayor San Andres, IIQ Chem Res Inst, Dept Inorgan Chem & Mat Sci Adv Mat, La Paz 303, Bolivia..
    Synthesis and Characterization of LiFePO4-PANI Hybrid Material as Cathode for Lithium-Ion Batteries2020In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 13, no 12, article id 2834Article in journal (Refereed)
    Abstract [en]

    This work focuses on the synthesis of LiFePO4-PANI hybrid materials and studies their electrochemical properties (capacity, cyclability and rate capability) for use in lithium ion batteries. PANI synthesis and optimization was carried out by chemical oxidation (self-assembly process), using ammonium persulfate (APS) and H3PO4, obtaining a material with a high degree of crystallinity. For the synthesis of the LiFePO4-PANI hybrid, a thermal treatment of LiFePO(4)particles was carried out in a furnace with polyaniline (PANI) and lithium acetate (AcOLi)-coated particles, using Ar/H(2)atmosphere. The pristine and synthetized powders were characterized by XRD, SEM, IR and TGA. The electrochemical characterizations were carried out by using CV, EIS and galvanostatic methods, obtaining a capacity of 95 mAhg(-1)for PANI, 120 mAhg(-1)for LiFePO(4)and 145 mAhg(-1)for LiFePO4-PANI, at a charge/discharge rate of 0.1 C. At a charge/discharge rate of 2 C, the capacities were 70 mAhg(-1)for LiFePO(4)and 100 mAhg(-1)for LiFePO4-PANI, showing that the PANI also had a favorable effect on the rate capability.

  • 11.
    Akbar, Nabeela
    et al.
    China Univ Geosci, Fac Mat Sci & Chem, Engn Res Ctr Nanogeo Mat, Minist Educ, 388 Lumo Rd, Wuhan 430074, Peoples R China..
    Paydar, Sara
    China Univ Geosci, Fac Mat Sci & Chem, Engn Res Ctr Nanogeo Mat, Minist Educ, 388 Lumo Rd, Wuhan 430074, Peoples R China..
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Southeast Univ, Sch Energy & Environm, Energy Storage Joint Res Ctr, Jiangsu Prov Key Lab Solar Energy Sci & Technol, 2 Si Pai Lou, Nanjing 210096, Peoples R China.
    Akbar, Muhammad
    Hubei Univ, Fac Phys & Elect Sci, Hubei Key Lab Ferro & Piezoelect Mat & Devices, Wuhan 430062, Hubei, Peoples R China..
    Shah, Muhammad Ali Kamran Yousaf
    Southeast Univ, Sch Energy & Environm, Energy Storage Joint Res Ctr, Jiangsu Prov Key Lab Solar Energy Sci & Technol, 2 Si Pai Lou, Nanjing 210096, Peoples R China..
    Ge, Wen
    China Univ Geosci, Fac Mat Sci & Chem, Engn Res Ctr Nanogeo Mat, Minist Educ, 388 Lumo Rd, Wuhan 430074, Peoples R China..
    Zhu, Bin
    China Univ Geosci, Fac Mat Sci & Chem, Engn Res Ctr Nanogeo Mat, Minist Educ, 388 Lumo Rd, Wuhan 430074, Peoples R China.;Southeast Univ, Sch Energy & Environm, Energy Storage Joint Res Ctr, Jiangsu Prov Key Lab Solar Energy Sci & Technol, 2 Si Pai Lou, Nanjing 210096, Peoples R China..
    Tunning tin-based perovskite as an electrolyte for semiconductor protonic fuel cells2022In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 47, no 8, p. 5531-5540Article in journal (Refereed)
    Abstract [en]

    The use of ceramic semiconductors to serve as an efficient proton conductor is an evolving approach in the novel emerging field of semiconductor protonic fuel cells (SPFCs). One of the most critical challenges in SPFCs is to design a sufficient proton-conductivity of 0.1 S cm(-1) below <600 degrees C. Here we report to tune the perovskite BaSnO3 (BSO), a semi-conductor single-phase material, to be applied as a proton-conducting electrolyte for SPFC. It was found that the oxygen vacancies play a vital role to promote proton transport while the electronic short-circuiting issue of BSO semiconductor has been justified by the Schottky junction mechanism at the anode/electrolyte interface. We have demonstrated a SPFC device to deliver a maximum power density of 843 mW cm(-2) with an ionic conductivity of 0.23 S cm(-1) for BSO at 550 degrees C. The oxygen vacancy formation by increasing the annealing temperature helps to understand the proton transport mechanism in BSO and such novel low-temperature SPFC (LT-SPFC).

  • 12.
    Al Husseinat, Ali
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Persson, Emma
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Carlhamn Rasmussen, Ran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rynkiewicz, Filip
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Lignin/Carbon Fibre Composites2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The market is in great need of more environmentally friendly alternatives to fossil-based composite materials to obtain a more sustainable future. Lignin is the second most common biopolymer and is a byproduct in the pulping and paper industry. Fractionation of lignin has made it possible to receive lignin with narrow dispersity and low molecular weight, which is suitable for further applications. Modification of lignin structure yields new reactive sites that can be tailored for specific needs. Because of the aromatic structure of lignin, it is a promising renewable resource for production of thermosets. In this project Kraft lignin is sequentially solvent-fractionated and modified in an allylation process with allyl chloride. The allylated lignin is reacted with a cross-linking agent and used to impregnate carbon fibre mats. The resin-coated material is then cured at 125 oC to achieve a composite material. The project also encompasses characterization of the chemical structure of lignin in the different fractions. The morphology and adhesive properties of the lignin as well as the carbon fibres and the composite material was investigated. Although the production of composite material from lignin and carbon fibres were accomplished, bubble formation in the resin was a problem for all composite samples that were prepared, whether it was during solvent evaporation or during curing. By performing the addition of resin to carbon fibre mats in multiple steps, where pressure is added after the first applied layer, it is suggested that complete adhesion to the carbon fibre can be achieved, whilst maintaining adequate resin to carbon fibre ratio. 

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  • 13. Alaghmandfard, A.
    et al.
    Sedighi, O.
    Tabatabaei Rezaei, N.
    Abedini, A. A.
    Malek Khachatourian, A.
    Toprak, Muhammet
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Seifalian, A.
    Recent advances in the modification of carbon-based quantum dots for biomedical applications2021In: Materials science & engineering. C, biomimetic materials, sensors and systems, ISSN 0928-4931, E-ISSN 1873-0191, Vol. 120, article id 111756Article, review/survey (Refereed)
    Abstract [en]

    Carbon-based quantum dots (CDs) are mainly divided into two sub-groups; carbon quantum dots (CQDs) and graphene quantum dots (GQDs), which exhibit outstanding photoluminescence (PL) properties, low toxicity, superior biocompatibility and facile functionalization. Regarding these features, they have been promising candidates for biomedical science and engineering applications. In this work, we reviewed the efforts made to modify these zero-dimensional nano-materials to obtain the best properties for bio-imaging, drug and gene delivery, cancer therapy, and bio-sensor applications. Five main surface modification techniques with outstanding results are investigated, including doping, surface functionalization, polymer capping, nano-composite and core-shell structures, and the drawbacks and challenges in each of these methods are discussed.

  • 14.
    Alexakis, Alexandros Efraim
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Jerlhagen, Åsa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Telaretti Leggieri, Rosella
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Eliasson, Adrian
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Benselfelt, Tobias
    School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Modification of CNF‐Networks by the Addition of Small Amounts of Well‐Defined Rigid Cationic Nanolatexes2022In: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935, Vol. 224, no 1, p. 2200249-2200249Article in journal (Refereed)
    Abstract [en]

    Cellulose nanofibril (CNF)-networks are modified by the addition of small amounts (below 10 wt%) of well-defined cationic nanolatexes synthesized through reversible addition–fragmentation chain-transfer-mediated polymerization-induced self-assembly (PISA). Minute amounts of nanolatex inclusions lead to increased tensile and shear moduli, indicating that nanolatexes can act as bridging-points between CNFs. At higher nanolatex content, this stiffening effect is lost, likely due to interactions between nanolatexes leading to plasticization. The influence of nanolatex content and size on interparticle distance is discussed and is used as a tool to understand the effects observed in macroscopic properties. Upon annealing, the stiffening effect is lost due to the softening of the nanolatexes, indicating that the core–shell morphology is a prerequisite for this effect. These systems form a versatile platform to develop fundamental insights into complex condensed colloidal systems, to ultimately aid in the development of new sustainable material concepts.

  • 15.
    Alexakis, Alexandros Efraim
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Telaretti Leggieri, Rosella
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Benselfelt, Tobias
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. School of Materials Science and Engineering, Nanyang Technological University, 639798 Singapore, Singapore.
    Nanolatex architectonics: Influence of cationic charge density and size on their adsorption onto surfaces with a 2D or 3D distribution of anionic groups2023In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 634, p. 610-620Article in journal (Refereed)
  • 16.
    Alexis, naza
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Corrosion behavior of lead-free and dezincification resistant brass alloys in tap water2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Dezincification resistant (DZR) and lead-free brass alloys continue to be widely applied replacing lead containing brasses in the drinking water sector. Due to the limited number of corrosion studies of these alloys in tap water, the present thesis was initiated with the aim to understand how the water type, its temperature and exposure duration can affect the corrosion behavior. Three DZR brass alloys were studied in order to evaluate their corrosion behavior in tap water of varying characteristics. The alloys included were two lead-free brasses (CW511L and CW724R) and a leaded brass alloy (CW602N) considered as a reference material. A combination of electrochemical, microscopic and surface analytical techniques were adopted to explore the corrosion form, mechanisms and corrosion rate. While these alloys passed the dezincification test as per ISO 6509-1:2014, the aim was to assess their corrosion performance in tap water.

    The influence of water chemistry parameters including pH, chloride concentration and alkalinity on the corrosion resistance of the three DZR alloys was investigated in short-term exposures (24 h). Depending on the brass alloy, the corrosivity of the test waters varied. The results show grade CW511L to be more sensitive in tap water of higher chloride concentration (44.7 mg/L) and alkalinity (310 mg/L) compared with low pH (6.9). However, opposite results were obtained for both CW724R and CW602N. The corrosivity of the test water was also affected by the temperature when increased from 22°C to 50°C during 24 h of immersion. While no dezincification features were observed on the surfaces, a combination of general and localized corrosion was observed to a largely variable extent between the alloys. The extent of initiation of localized corrosion varied with test water and alloy composition. While CW724R and CW602N showed similar high susceptibility to localized corrosion in the alkaline (pH 8.2) tap water, CW511L was more prone to pitting corrosion in tap water of low pH (6.9). The effect of exposure duration was explored in the alkaline test water for the three brasses up to 72 days. Corrosion rates based on weight loss showed an expected initial high corrosion rate which declined with continuous immersion, leading to low and similar corrosion rates for all three brass alloys after 72 days. Thus, at given test conditions, the lead-free brasses showed good corrosion behavior being competitive to the performance of lead containing brass. Therefore, lead-free brass alloys are good candidates to substitute lead-containing brasses in tap water applications.

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  • 17. Al-Hamdi, Abdullah M.
    et al.
    Sillanpaa, Mika
    Bora, Tanujjal
    Dutta, Joydeep
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Efficient photocatalytic degradation of phenol in aqueous solution by SnO2:Sb nanoparticles2016In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 370, p. 229-236Article in journal (Refereed)
    Abstract [en]

    Photodegradation of phenol in the presence of tin dioxide (SnO2) nanoparticles under UV light irradiation is known to be an effective photocatalytic process. However, phenol degradation under solar light is less effective due to the large band gap of SnO2. In this study antimony (Sb) doped tin dioxide (SnO2) nanoparticles were prepared at a low temperature (80 degrees C) by a sol-gel method and studied for its photo catalytic activity with phenol as a test contaminant. The catalytic degradation of phenol in aqueous media was studied using high performance liquid chromatography and total organic carbon measurements. The change in the concentration of phenol affects the pH of the solution due to the by-products formed during the photo-oxidation of phenol. The photoactivity of SnO2:Sb was found to be a maximum for 0.6 wt.% Sb doped SnO2 nanoparticles with 10 mg L-1 phenol in water. Within 2 h of photodegradation, more than 95% of phenol could be removed under solar light irradiation.

  • 18. Ali, A.
    et al.
    Rafique, A.
    Kaleemullah, M.
    Abbas, G.
    Ajmal Khan, M.
    Ahmad, M. A.
    Raza, Rizwan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Chinese Academy of Sciences, China.
    Effect of Alkali Carbonates (Single, Binary, and Ternary) on Doped Ceria: A Composite Electrolyte for Low-Temperature Solid Oxide Fuel Cells2018In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 1, p. 806-818Article in journal (Refereed)
    Abstract [en]

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

  • 19.
    Ali, Aya
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Reaction of Copper and Copper(I) Iodide with Iodine and Strong Field Ligands2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Perovskit solceller (PSCs) är kända som 'ljusomvandling' enheter med ökad omvandlingseffektivitiet (PCE). PSCs är kända för detta flexibilitet och hög tolerans mot defekter och består av fem lager med olika material och egenskaper. De fem lagren är följande; transparant elektrod, elektron ledande lager (ETL), perovskit lager, hål ledande lager (HTL) och metallelektroden. 

    Detta forskningsarbete fokuserar på metallelektroden (Cu-tunn film), HTL (CuI-tunn film) och det aktiva lagret (CuI-komplex). 

    Syftet med denna studie är att undersöka effekten av olika tjocklekar på ytans morfologi och grovhet för att se mängden jod som tränger sig genom filmen genom att beräkna volymen. 

    Resultatet av denna studie visar att ökad tjocklek leder till ökad grovhet. Man ser även att en ökad tjocklek leder till ett mer homogent och jämn yta, och dessutom ökar kornstorleken, vilket tyder på att kvaliten av kristallisationen förbättras. 

    Slutligen, genom att känna till tjockleken och storleken (arean) på ytan av proverna kunde man beräkna volymen för att indikera mängden jod som trängt sig genom filmen. Resultatet av denna del indikerade att ju tjockare provet är, desto mer kommer jod att tränga sig genom filmen.

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  • 20.
    Alimohammadi, Vahid
    et al.
    Univ Tehran, Sch Met & Mat, Coll Engn, Adv Magnet Mat Res Ctr, Tehran 111554563, Iran..
    Seyyed Ebrahimi, Seyyed Ali
    Univ Tehran, Sch Met & Mat, Coll Engn, Adv Magnet Mat Res Ctr, Tehran 111554563, Iran..
    Kashanian, Faezeh
    Univ Tehran, Sch Biol, Coll Sci, Tehran 111554563, Iran..
    Lalegani, Zahra
    Univ Tehran, Sch Met & Mat, Coll Engn, Adv Magnet Mat Res Ctr, Tehran 111554563, Iran..
    Habibi-Rezaei, Mehran
    Univ Tehran, Sch Biol, Coll Sci, Tehran 111554563, Iran..
    Hamawandi, Bejan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Hydrophobic Magnetite Nanoparticles for Bioseparation: Green Synthesis, Functionalization, and Characterization2022In: MAGNETOCHEMISTRY, ISSN 2312-7481, Vol. 8, no 11, p. 143-, article id 143Article in journal (Refereed)
    Abstract [en]

    In this study, three types of hydrophobized alkyl-modified magnetic nanoparticles (MNPs) comprising direct alkylated-MNPs (A-MNPs), silica-mediated alkyl MNPs (A-SiMNPs), and arginine (Arg)-mediated alkyl MNPs (A-RMNPs) were synthesized successfully. For this purpose, the co-precipitation method was used to synthesize, and octadecyl trimethoxy silane (OTMS) was used as a functionalizing agent. Accordingly, the hydrophobic octadecyl moieties were connected to MNPs. The nanoparticles (NPs) were characterized by XRD, SEM, FTIR, CHN, DLS, and zeta potential analyses. The synthesized coated MNPs represented a decrease in surface charge and magnetization alongside increased surface hydrophobicity and size. It was revealed that the alkylation process was successfully performed to all three MNPs, but A-SiMNPs showed the highest hydrophobicity. Additionally, the novel A-RMNPs, as the most biocompatible type, and A-MNPs showed the highest magnetization among the synthesized MNPs. The results indicate that synthesized NPs can play an important role in bio applications. However, it was revealed that alkyl chains are easily connected to all three MNPs, and that A-MNPs contained the highest alkyl chains and could affect the re-folding and denaturation process of recombinant proteins.

  • 21.
    Alinejadian, Navid
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Tallinn Univ Technol TalTech, Dept Mech & Ind Engn, EE-19086 Tallinn, Estonia..
    Kazemi, Sayed Habib
    Inst Adv Studies Basic Sci, Dept Chem, Zanjan 4513766731, Iran..
    Nasirpouri, Farzad
    Sahand Univ Technol, Fac Mat Engn, Sahand New Town 5331811111, East Azerbaijan, Iran..
    Odnevall, Inger
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Karolinska Inst, AIMES Ctr Advancement Integrated Med & Engn Sci, Stockholm, Sweden.;Karolinska Inst, Dept Neurosci, SE-17177 Stockholm, Sweden..
    Electro-deposited nano-Ni/reduced graphene oxide composite film of corrugated surface for high voltammetric sensitivity2023In: Materials Chemistry and Physics, ISSN 0254-0584, E-ISSN 1879-3312, Vol. 297, p. 127288-, article id 127288Article in journal (Refereed)
    Abstract [en]

    Reduced graphene oxide (rGO) is an ideal candidate in nanostructured metallic materials to enhance their electrochemical performance. However, few studies exist on the effects of rGO on the crystallographic, physical, and topological properties of co-electrodeposited Ni/rGO nanocomposites. In this study, the morphology and normalized electro-active specific surface (NESS) of a Ni/rGO nanocomposite were correlated with its crystal-lographic properties by varying the applied co-electrodeposition current density (0.01-0.1 A cm(-2)) and rGO concentration (0.5-2 mg mL(-1)). Tuning was done to achieve the best physical and electrochemical properties of the nanocomposite at alkaline (NaOH) conditions in terms of the highest NESS (12.3 x 10(-4)) and electro-active sensitivity (17.3 mu A mM(-1) cm(-2)) possible. The findings of the study show a possible approach to enhance the performance of electro-active components such as electrochemical devices, sensors, and actuators.

  • 22.
    Alinejadian, Navid
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Tallinn, 19086, Estonia.
    Kazemi, Sayed Habib
    Inst Adv Studies Basic Sci, Dept Chem, Zanjan 4513766731, Iran..
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. AIMES-Center for the Advancement of Integrated Medical and Engineering Sciences; Department of Neuroscience, Karolinska Institutet, Stockholm, 171 77, Sweden.
    SLM-processed MoS2/Mo2S3 nanocomposite for energy conversion/storage applications2022In: Scientific Reports, E-ISSN 2045-2322, Vol. 12, no 1, article id 5030Article in journal (Refereed)
    Abstract [en]

    MoS2-based nanocomposites have been widely processed by a variety of conventional and 3D printing techniques. In this study, selective laser melting (SLM) has for the first time successfully been employed to tune the crystallographic structure of bulk MoS2 to a 2H/1T phase and to distribute Mo2S3 nanoparticles in-situ in MoS2/Mo2S3 nanocomposites used in electrochemical energy conversion/storage systems (EECSS). The remarkable results promote further research on and elucidate the applicability of laser-based powder bed processing of 2D nanomaterials for a wide range of functional structures within, e.g., EECSS, aerospace, and possibly high-temperature solid-state EECSS even in space.

  • 23.
    Alinejadian, Navid
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Tallinn Univ Technol TalTech, Dept Mech & Ind Engn, EE-19086 Tallinn, Estonia.
    Nasirpouri, Farzad
    Sahand Univ Technol, Fac Mat Engn, Sahand New Town 513351996, East Azerbaijan, Iran..
    Yus, Joaquin
    CSIC, Inst Ceram & Vidrio, Madrid 28049, Spain..
    Ferrari, Begona
    CSIC, Inst Ceram & Vidrio, Madrid 28049, Spain..
    Reduction-based engineering of three-dimensional morphology of Ni-rGO nanocomposite2021In: Materials Science & Engineering: B. Solid-state Materials for Advanced Technology, ISSN 0921-5107, E-ISSN 1873-4944, Vol. 271, article id 115259Article in journal (Refereed)
    Abstract [en]

    Relying on the reduction of oxygenated functional groups of graphene oxide, the engineering of the morphology of Ni-based reduced graphene oxide (Ni-rGO) nanocomposite was carried out via galvanostatic electrochemical co-deposition by changing the current density in a range of 0.001-0.01 A.cm(-2) and loading of 2 g.L-1 of graphene oxide. The morphology has been converted to a porous, rough, and three-dimensional (3D) form by significant incorporation and simultaneous reduction of GO into the structure of Ni-rGO nanocomposite film. Study on 3D morphology by SEM, FT-IR, XRD, and Raman confocal spectroscopy approved simultaneously reduction of oxygenated functional groups. Moreover, we have discussed the impact of rGO incorporated in the structure of Ni-rGO nanocomposite onto the creation of porous 3D-morphology and the enhancement of the electroactive specific surface. This new fascinating mechanism and structure can lead to the enhancement of electroactive components in electrochemical sensors and energy conversion-storage systems.

  • 24. Almessiere, M. A.
    et al.
    Slimani, Y.
    Trukhanov, A. V.
    Sadaqat, A.
    Korkmaz, A. D.
    Algarou, N. A.
    Aydın, H.
    Baykal, A.
    Toprak, Muhammet
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Review on functional bi-component nanocomposites based on hard/soft ferrites: Structural, magnetic, electrical and microwave absorption properties2021In: Nano-Structures and Nano-Objects, ISSN 2352-507X, Vol. 26, article id 100728Article in journal (Refereed)
    Abstract [en]

    Bi-component hard (H) (hexaferrite) and soft (S) (spinel) ferrites nanocomposites are gaining interest scientifically and technically, not only for combining the high magnetization of spinel ferrite nanomaterials and the high coercivity of hexaferrite magnetic nanomaterials but also for the outstanding exchange-coupling behavior among hard and soft magnetic phase. The improved magnetic features lead to produce a new nanocomposite with higher microwave absorption capacity in comparison with ferrites with a single absorption mechanism. Exchange-coupled effect has a potential application based on microwave absorption, recording media, permanent magnets, biomedical and other applications. Intensive studies have been conducted on this topic to produce hard/soft (H/S) ferrite nanocomposites with establishment of exchange coupled effect between the two phases. Preparation methods, microstructure, magnetics features, microwave and dielectric properties, and applications are elaborated. Consequently, a comprehensive effort has been made to contain an original reference investigating in detail the precise outcomes of the published papers. 

  • 25.
    Al-Soubaihi, Rola
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Saoud, Khaled Mohammad
    Virginia Commonwealth Univ Qatar, Liberal Arts & Sci Program, POB 8095, Doha, Qatar..
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Comparative investigation of structure and operating parameters on the performance and reaction dynamic of CO conversion on silica aerogel and fumed-silica-supported Pd catalysts2022In: SURFACES AND INTERFACES, ISSN 2468-0230, Vol. 29, p. 101776-, article id 101776Article in journal (Refereed)
    Abstract [en]

    The catalyst morphology, metal-support interaction, and reaction conditions greatly influence the catalytic performance and reaction dynamics. Similarly, the dispersion of the metal within the support plays a crucial in the thermal stability and sintering of the catalyst. Furthermore, temperature-dependent conversion hysteresis is well-known to occur during ignition and extinction of exothermic CO oxidation over supported Pd catalysts due to the variation of CO adsorption on the surface or bulk oxidation of Pd and the ability of the catalyst regenerate the active sites. Herein, the catalytic performance and the hysteresis behavior of mesoporous silica aerogel supported Pd (Pd/a-SiO2), and commercial fumed silica-supported Pd (Pd/f-SiO2) were investigated compared using CO oxidation as a probe reaction under different reaction conditions and operating parameters (i.e., catalyst weight, ramp rate, and flow rate). Surface and morphologic examination using XPS, FTIR, and of Pd/a-SiO2 and Pd/f-SiO2 reveal a strong correlation between the catalyst surface and structure and its catalytic performance and stability under different reaction parameters. Moreover, this study presents the effect of surface area, particle size, and size distribution on diffusion and mass transport of reactants (CO, O-2) and products (CO2) and active sites accessibility. This study showed that Pd/f-SiO2 had better efficiency under high (turbulence) flow. Moreover, intrinsic apparent activation energy (E-a) and the number of active sites were calculated from the Kinetics of CO oxidation fitted using Arrhenius plots indicate that the ramp rate has less effect on Pd/f-SiO2 catalytic behavior. though, Pd/f-SiO2 had higher relative active sites than Pd/a-SiO2, (E-a) was lower. Cyclic stability and long-term stabilities showed that both catalysts are stable and can regenerate the active sites. The current study contributes to understanding the catalysts' surface, structural and morphological properties on the catalysts' performance toward CO oxidation and other reactions under dynamic conditions.

  • 26.
    Al-Soubaihi, Rola
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Saoud, Khaled Mohammad
    Virginia Commonwealth Univ Qatar, Liberal Arts & Sci Program, POB 8095, Doha, Qatar..
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Low-temperature CO oxidation by silver nanoparticles in silica aerogel mesoreactors2023In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 455, p. 140576-, article id 140576Article in journal (Refereed)
    Abstract [en]

    Low-temperature carbon monoxide (CO) oxidation on silver/silica aerogel (Ag/SiO2 AG) catalyst prepared by one-pot sol-gel synthesis followed by supercritical ethanol drying method is reported. Highly stable and sinterproof catalyst led to easy reactant diffusion to the active sites. The Ag/SiO2 AG catalyst showed enhanced catalytic activity toward low-temperature CO oxidation by preventing agglomeration of silver nanoparticles inside pores and facilitating well-dispersed active sites to enhance the mass heat transfer in the mesopores. Catalyst pretreatment conditions were found to play a crucial role in achieving high CO conversion efficiency at low light-off temperatures. Inverse counter-clockwise CO oxidation hysteresis was found to occur after the first run. The active sites contributing to this enhanced catalytic behavior were confirmed to be Ag0 from XPS, XRD, and TEM analysis. The catalyst exhibited good thermal stability up to 450 degrees C over repeated number of cycles.

  • 27.
    Alterby, Malin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Johnson, Emily
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Jonason, Anton
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Svensson, Denize
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    3D Printing Hydrogel Artificial Muscles and Microrobotics2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this lab was to investigate the printability of cellulose nanofiber/carbon nanotubes, their functions as actuators, and to compare these properties with MXene/nano cellulose gels. Data on MXene/nano cellulose gel was obtained from previous research made by Hamedi labs. Data on carbon nanotubes were collected through experiments evaluating different concentrations and sonication times to yield a gel with high conductivity and viscosity. While it was concluded that both gels could be printed into 2D or 3D shapes, the latter failed to maintain its structure over time due to issues with drying. However, it was found that only 2D MXene/CNF could be used as a reversible actuator.

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  • 28.
    Alvarado Ávila, María Isabel
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Toledo-Carrillo, Esteban Alejandro
    KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova. KTH, School of Engineering Sciences (SCI), Applied Physics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Improved chlorate production with platinum nanoparticles deposited on fluorinated activated carbon cloth electrodes2020In: Cleaner Engineering and Technology, ISSN 2666-7908, Vol. 1, article id 100016Article in journal (Refereed)
    Abstract [en]

    Sodium chlorate is one of the main oxidizing agents used in the wood industry due to their capability of use as an elemental chlorine-free (CEF) bleaching. A simple way to produce chlorates is by the electrolysis of an aqueous sodium chloride (NaCl) solution. In the present study activated carbon cloth electrodes (ACC) modified with fluorine and platinum nanoparticles (Pt–F/ACC and Pt/ACC) were used as one of the electrodes. Electrofluorination was used for fluorination of the anodes and polyol method was used for the synthesis of platinum nanoparticles. Chlorate production using a typical solution of 100 ​g/l of sodium chloride (NaCl) and 2 ​g/l sodium chromate (Na2Cr2O7) and an applied current of 0.540 ​A was studied. Prior to the electrolysis assays, the microstructural properties of the electrodes were characterized by scanning electron microscopy and surface modifications and bonding using infra-red (FTIR) spectroscopy. Electrochemical properties were determined using cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. Interaction between fluorine (F) and platinum (Pt) on the electrode leads to an improvement of the electrocatalytic properties for chlorine evolution as observed from the increase in the current efficiency from 37.5% at 78.5% after 150 ​min of continuous electrolysis using Pt–F/ACC anodes. The results suggest that modified activated carbon material is an attractive and economical alternative as electrodes for chlorate production. 

  • 29.
    Amagat, Jordi
    et al.
    Aarhus Univ, Dept Biol & Chem Engn, Aarhus, Denmark.;Univ Chinese Acad Sci, Sinodanish Coll SDC, Beijing 101400, Peoples R China..
    Su, Yingchun
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems, Electronic and embedded systems. Aarhus Univ, Dept Biol & Chem Engn, Aarhus, Denmark..
    Svejso, Frederik Hobjerg
    Aarhus Univ, Dept Biol & Chem Engn, Aarhus, Denmark..
    Le Friec, Alice
    Aarhus Univ, Dept Biol & Chem Engn, Aarhus, Denmark..
    Sonderskov, Steffan Moller
    Aarhus Univ, INANO, Interdisciplinary Nanosci Ctr, Aarhus, Denmark..
    Dong, Mingdong
    Aarhus Univ, INANO, Interdisciplinary Nanosci Ctr, Aarhus, Denmark..
    Fang, Ying
    Chinese Acad Sci, Ctr Excellence Nanosci, Natl Ctr Nanosci & Technol, Beijing 100190, Peoples R China.;Chinese Acad Sci, Inst Neurosci, CAS Ctr Excellence Brain Sci & Intelligence Techno, Shanghai 200031, Peoples R China..
    Chen, Menglin
    Aarhus Univ, Dept Biol & Chem Engn, Aarhus, Denmark.;Aarhus Univ, INANO, Interdisciplinary Nanosci Ctr, Aarhus, Denmark.;Aarhus Univ, Univ Byen 36, DK-8000 Aarhus, Denmark..
    Self-snapping hydrogel-based electroactive microchannels as nerve guidance conduits2022In: MATERIALS TODAY BIO, ISSN 2590-0064, Vol. 16, article id 100437Article in journal (Refereed)
    Abstract [en]

    Peripheral nerve regeneration with large defects needs innovative design of nerve guidance conduits (NGCs) which possess anisotropic guidance, electrical induction and right mechanical properties in one. Herein, we present, for the first time, facile fabrication and efficient neural differentiation guidance of anisotropic, conductive, self-snapping, hydrogel-based NGCs. The hydrogels were fabricated via crosslinking of graphitic carbon nitride (g-C3N4) upon exposure with blue light, incorporated with graphene oxide (GO). Incorporation of GO and in situ reduction greatly enhanced surface charges, while decayed light penetration endowed the hydrogel with an intriguing self-snapping feature by the virtue of a crosslinking gradient. The hydrogels were in the optimal mechanical stiffness range for peripheral nerve regeneration and supported normal viability and proliferation of neural cells. The PC12 cells differentiated on the electroactive g-C3N4 H/rGO3 (3 mg/mL GO loading) hydrogel presented 47% longer neurite length than that of the pristine g-C3N4 H hydrogel. Furthermore, the NGC with aligned microchannels was successfully fabricated using sacrificial melt electrowriting (MEW) moulding, the anisotropic microchannels of the 10 mu m width showed optimal neurite guidance. Such anisotropic, electroactive, self-snapping NGCs may possess great potential for repairing peripheral nerve injuries.

  • 30.
    Amizhtan, S. K.
    et al.
    Indian Inst Technol Madras IIT Madras, Dept Elect Engn, Chennai 600036, India..
    Sarathi, R.
    Indian Inst Technol Madras IIT Madras, Dept Elect Engn, Chennai 600036, India..
    Edin, Hans Ezz
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering and Fusion Science.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering and Fusion Science.
    Study on Conduction Mechanism in Corrosive Transformer Oil and its Reclamation Properties2023In: IEEE transactions on dielectrics and electrical insulation, ISSN 1070-9878, E-ISSN 1558-4135, Vol. 30, no 5, p. 2232-2239Article in journal (Refereed)
    Abstract [en]

    This work deals with the effect of oil reclamation on the conduction mechanism and dielectric aspects of accelerated thermally aged transformer mineral oil. The reclamation is a treatment with Fuller's earth (FE) adsorbent to remove corrosive sulfur compounds and other contaminants formed during thermal aging. The properties of the oil are compared between different stages of the treatment. Corona (partial discharge) inception is identified by the optical fluorescent fiber technique. The results show an increased corona inception voltage after treatment. Dielectric response spectroscopy (DRS) showed a lower loss factor and electrical conductivity after treatment. The conduction mechanism is measured under uniform and nonuniform electric fields with variations in applied voltage magnitude. The conduction mechanism at a uniform electric field (low E) is studied using the polarity reversal technique to estimate the respective ionic motilities in the fluid. The apparent mobility of ions, conductivity, ionic radius, and concentration from the oil are found to reduce on reclamation. In addition, the conduction mechanism for a higher electric field is simulated by the current-voltage characteristic in nonuniform conditions and the slope determines the ionic mobility of the fluid.

  • 31. An, J.
    et al.
    Yang, X.
    Wang, W.
    Li, J.
    Wang, H.
    Yu, Z.
    Gong, C.
    Wang, X.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Stable and efficient PbS colloidal quantum dot solar cells incorporating low-temperature processed carbon paste counter electrodes2017In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 158, p. 28-33Article in journal (Refereed)
    Abstract [en]

    Colloidal quantum dot (CQD) solar cells with a ZnO/PbS-TBAI/PbS-EDT/carbon structure were prepared using a solution processing technique. A commercially available carbon paste that was processed at low-temperatures was used as a counter electrode in place of expensive noble metals, such as Au or Ag, which are used in traditional PbS CQD solar cells. These CQD solar cells exhibited remarkable photovoltaic performance with a short circuit density (Jsc) of 25.6 mA/cm2, an open circuit voltage (Voc) of 0.45 V, a fill factor (FF) of 51.8% and a power conversion efficiency (PCE) as high as 5.9%. A reference device with an Au counter electrode had a PCE of 6.0%. The PCE of the carbon-containing CQD solar cell remained stable for 180 days when tested in ambient atmosphere, while the PCE of the Au-containing CQD solar cell lost 48.3% of its original value. Electrochemical impedance spectroscopy (EIS) demonstrated that holes within the PbS CQD were effectively transported to the carbon counter electrode.

  • 32.
    Anandhakumari, Govindharaj
    et al.
    Department of Physics, Gobi Arts & Science College, Gobichettipalayam, Erode, Tamilnadu-638 453, India.
    Jayabal, Palanisamy
    Department of Physics, Gobi Arts & Science College, Gobichettipalayam, Erode, Tamilnadu-638 453, India.
    Balasankar, Athinarayanan
    Department of Physics, Gobi Arts & Science College, Gobichettipalayam, Erode, Tamilnadu-638 453, India.
    Ramasundaram, Subramaniyan
    School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Korea.
    Oh, Tae Hwan
    School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Korea.
    Aruchamy, Kanakaraj
    School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Korea.
    Kallem, Parashuram
    Department of Environmental and Public Health, College of Health Sciences, Abu Dhabi University, Abu Dhabi, P.O. Box 59911, United Arab Emirates.
    Polisetti, Veerababu
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Synthesis of strontium oxide-zinc oxide nanocomposites by Co-precipitation method and its application for degradation of malachite green dye under direct sunlight2023In: Heliyon, E-ISSN 2405-8440, Vol. 9, no 10, article id e20824Article in journal (Refereed)
    Abstract [en]

    Photocatalysts workable under direct sunlight are the safe and cost-effective option for water purification. The nanocomposites of strontium oxide and zinc oxide (SZ NCs) were synthesized using coprecipitation method. The respective precursors of SZ NCs were subjected to alkaline hydrolysis and subsequently thermally treated to yield SZ NCs. The SZ NCs with different ZnO composition was synthesized by varying the concentration of ZnO precursor from 0.2 to 1 M. The structural properties of SZ NCs evaluated using X-Ray diffraction (XRD), Thermogravimetric analysis (TGA), and Differential thermal analysis DTA). The optical properties of SZ NCs studied using ultraviolet–visible (UV–Vis) spectroscopic study. The trend observed in the intensity of XRD peaks indicated the occurrence of Zn doping in the crystalline lattice of SrO and the formation of SrO–ZnO composite. Upon incorporation of 1 M of ZnO precursor, the grain size of the SrO was decreased from 49.3 to 27.6 nm. The weight loss in the thermal analysis indicates the removal of carbonates from the sample upon heating and shows the formation of an oxide structure. UV–Vis spectra confirmed that the presence of SrO enhanced the sunlight absorption of SZ NCs. The increase in the composition of ZnO precursors increased the bandgap of SrO (2.09 eV) to the level of ZnO (3.14 eV). SZ NCs exhibited heterostructure morphology, where the nanosized domains with varying shapes (layered and rod-like) were observed. Under direct sunlight conditions, SZ NCs prepared using 1 M/0.6 M of SrO/ZnO precursors exhibited 15–20 % higher photocatalytic efficiency than neat SrO and ZnO. In precise, 1 mg of this SZ NC was degraded 98 % of malachite green dye dissolved in water (10 ppm) under direct sunlight. Additionally, the thermal stability results showed that 18 % decomposition was obtained due to the degradation impurities in SrO/ZnO catalysts and the XRD results revealed that no structural change is obtained in SrO/ZnO photocatalysts after stability test. The SZ NCs can be effectively used as safe and economic sunlight photocatalysts for water purification in remote areas without the electricity.

  • 33.
    Andersson, Richard L.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Ström, Valter
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Gedde, Ulf W.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Mallon, Peter E.
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Olsson, Richard T.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Micromechanics of ultra-toughened electrospun PMMA/PEO fibres as revealed by in-situ tensile testing in an electron microscope2014In: Scientific Reports, E-ISSN 2045-2322, Vol. 4, p. 6335-Article in journal (Refereed)
    Abstract [en]

    A missing cornerstone in the development of tough micro/nano fibre systems is an understanding of the fibre failure mechanisms, which stems from the limitation in observing the fracture of objects with dimensions one hundredth of the width of a hair strand. Tensile testing in the electron microscope is herein adopted to reveal the fracture behaviour of a novel type of toughened electrospun poly(methyl methacrylate)/poly(ethylene oxide) fibre mats for biomedical applications. These fibres showed a toughness more than two orders of magnitude greater than that of pristine PMMA fibres. The in-situ microscopy revealed that the toughness were not only dependent on the initial molecular alignment after spinning, but also on the polymer formulation that could promote further molecular orientation during the formation of micro/nano-necking. The true fibre strength was greater than 150 MPa, which was considerably higher than that of the unmodified PMMA (17 MPa). This necking phenomenon was prohibited by high aspect ratio cellulose nanocrystal fillers in the ultra-tough fibres, leading to a decrease in toughness by more than one order of magnitude. The reported necking mechanism may have broad implications also within more traditional melt-spinning research.

  • 34.
    André, Magnus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Malmström, Maria E.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Neretnieks, Ivars
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Determining sorption coefficients in intact rock using an electrical potential gradient as a driving force for migration2006In: Scientific Basis for Nuclear Waste Management XXIX / [ed] VanIseghem, P, WARRENDALE, PA: MATERIALS RESEARCH SOCIETY , 2006, Vol. 932, p. 975-982Conference paper (Refereed)
    Abstract [en]

    The transport of radionuclides in indigenous rock is greatly affected by the sorption of cations in the porous rock matrix. For the determination of sorption coefficients, batch experiments have traditionally been used. For these experiments, the rock sample is crushed into fine particles to reduce the experimental time. However, this procedure increases the specific surface area of the sample and the new surfaces created could have different sorption qualities than the naturally occurring surfaces, which may impair the results of sorption coefficient determinations. A new method for determining sorption coefficients in intact rock is being developed, using electromigration as a means to speed up the transport process, thereby allowing for faster equilibration between the rock sample and the tracer solution. Here, we report results from preliminary experiments, using cesium as a sorbing tracer, showing a consistent difference between sorption coefficients obtained using electromigration methods on intact rock samples and traditional batch experiments on crushed samples.

  • 35.
    Andrén, Oliver C. J.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Zhang, Yuning
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Lundberg, Pontus
    Hawker, Craig J.
    Nyström, Andreas M.
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Therapeutic Nanocarriers via Cholesterol Directed Self-Assembly of Well-Defined Linear-Dendritic Polymeric Amphiphiles2017In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 29, no 9, p. 3891-3898Article in journal (Refereed)
    Abstract [en]

    A novel platform of fluorescently labeled nanocarriers (NCs) is herein proposed based on amphiphilic linear-dendritic polymeric hybrids. These sophisticated polymers were synthesized with a high degree of structural control at a macro-molecular level, displayed hydrophobic cholesterol compartments as chain-terminus groups of the dendritic block and hydrophilic bifunctional linear poly(ethylene glycol) (PEG) block. Spherical supramolecular assemblies with therapeutically relevant properties were successfully achieved including (i) sizes in the region of 100 to 200 nm; (ii) narrow dispersity profile with values close to 0.12; and (iii) self-assembly down to nanomolar concentrations. The modular nature of the NCs permitted the encapsulation of single or dual anticancer drugs and in parallel provide intracellular fluorescent traceability. As polymer therapeutics, the NCs were proven to penetrate the cancerous cell membranes and deliver the cargo of drugs into the nuclei as well as the cytoplasm and mitochondria. The dual drug delivery of both doxorubicin (DOX) and triptolide substantially enhanced the therapeutic efficacy with a 63% significant increase against resistant breast cancer cells when compared to free DOX.

  • 36.
    Anikina, Ekaterina
    et al.
    South Ural State Univ, Inst Nat Sci & Math, Chelyabinsk 454014, Russia.;Uppsala Univ, Dept Phys & Astron, Mat Theory Div, S-75120 Uppsala, Sweden..
    Hussain, Tanveer
    Univ Western Australia, Sch Mol Sci, Perth, WA 6009, Australia..
    Beskachko, Valery
    South Ural State Univ, Inst Nat Sci & Math, Chelyabinsk 454014, Russia..
    Bae, Hyeonhu
    Konkuk Univ, Dept Phys, Seoul 05029, South Korea..
    Lee, Hoonkyung
    Konkuk Univ, Dept Phys, Seoul 05029, South Korea..
    Ahuja, Rajeev
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Properties. Uppsala Univ, Dept Phys & Astron, Mat Theory Div, S-75120 Uppsala, Sweden.;KTH Royal Inst Technol, Appl Mat Phys, Dept Mat & Engn, S-10044 Stockholm, Sweden..
    Tunning Hydrogen Storage Properties of Carbon Ene-Yne Nanosheets through Selected Foreign Metal Functionalization2020In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 124, no 31, p. 16827-16837Article in journal (Refereed)
    Abstract [en]

    In this study, we have employed density functional theory with a range of van der Waals corrections to study geometries, electronic structures, and hydrogen (H-2) storage properties of carbon ene-yne (CEY) decorated with selected alkali (Na, K) and alkaline-earth metals (Mg, Ca). We found that all metals, except Mg, bind strongly by donating a major portion of their valence electrons to the CEY monolayers. Thermal stabilities of representative systems, Ca-decorated CEY monolayers, have been confirmed through ab initio molecular dynamics simulations (AIMD). We showed that each metal cation adsorbs multiple H-2 with binding energies (E-bind) considerably stronger than on pristine CEY. Among various metal dopants, Ca stands out with the adsorption of five H-2 per each Ca having E-bind values within the desirable range for effective adsorption/desorption process. The resulting gravimetric density for CEY@Ca has been found around 6.0 wt % (DFT-D3) and 8.0 wt % (LDA), surpassing the U.S. Department of Energy's 2025 goal of 5.5 wt %. The estimated H-2 desorption temperature in CEY@Ca exceeds substantially the boiling point of liquid nitrogen, which confirms its potential as a practical H-2 storage medium. We have also employed thermodynamic analysis to explore the H-2 adsorption/desorption mechanism at varied conditions of temperature and pressure for real-world applications.

  • 37. Araujo, Rafael B.
    et al.
    Islam, M. S.
    Chakraborty, Sudip
    Ahuja, Rajeev
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Predicting electrochemical properties and ionic diffusion in Na2+2xMn2-x(SO4)(3): crafting a promising high voltage cathode material2016In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 4, no 2, p. 451-457Article in journal (Refereed)
    Abstract [en]

    Sodium ion batteries have emerged as a good alternative to lithium based systems due to their low cost of production. In this scenario, the search for higher voltage, sodium cathodes results in a new promising alluaudite structure Na2+2xMn2-x(SO4)(3). The structural, electronic and Na diffusion properties along with defects have been reported in this investigation within the framework of density functional theory. A band gap of 3.61 eV has been computed and the average deintercalation potential is determined to be 4.11 V vs. Na/Na+. A low concentration of anti-site defects is predicted due to their high formation energy. The biggest issue for the ionic diffusion in the Na2+2xMn2-x(SO4)(3) crystal structure is revealed to be the effect of Mn vacancies increasing the activation energy of Na+ ions that hop along the [001] equilibrium positions. This effect leads to activation energies of almost the same high values for the ionic hop through the [010] direction characterizing a 2D like ionic diffusion mechanism in this system.

  • 38.
    Aryal, Um Kanta
    et al.
    Mads Clausen Institute, Center for Advanced Photovoltaics and Thin Film Energy Devices (SDU CAPE), University of Southern Denmark, Sønderborg 6400, Denmark; SDU Climate Cluster, University of Southern Denmark, Odense 5230, Denmark.
    Pazniak, Hanna
    Université Grenoble Alpes, CNRS, Grenoble INP, LMGP, Grenoble, CS 50257, Grenoble Cedex 1 38016, France.
    Kumari, Tanya
    Mads Clausen Institute, Center for Advanced Photovoltaics and Thin Film Energy Devices (SDU CAPE), University of Southern Denmark, Sønderborg 6400, Denmark; SDU Climate Cluster, University of Southern Denmark, Odense 5230, Denmark.
    Weber, Matthieu
    Université Grenoble Alpes, CNRS, Grenoble INP, LMGP, Grenoble, CS 50257, Grenoble Cedex 1 38016, France.
    Johansson, Fredrik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry. Institut des Nanosciences de Paris, Sorbonne Universite, UMR CNRS 7588, F-75005 Paris, France.
    Vannucchi, Noemi
    Institut des Nanosciences de Paris, Sorbonne Universite, UMR CNRS 7588, F-75005 Paris, France; Division of X-ray Photon Science, Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden.
    Witkowski, Nadine
    Institut des Nanosciences de Paris, Sorbonne Universite, UMR CNRS 7588, F-75005 Paris, France.
    Turkovic, Vida
    Mads Clausen Institute, Center for Advanced Photovoltaics and Thin Film Energy Devices (SDU CAPE), University of Southern Denmark, Sønderborg 6400, Denmark; SDU Climate Cluster, University of Southern Denmark, Odense 5230, Denmark.
    Di Carlo, Aldo
    Istituto di Struttura della Materia, CNR-ISM, Via del Fosso del Cavaliere 100, Rome 00133, Italy, Via del Fosso del Cavaliere 100; CHOSE (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering, University of Rome “Tor Vergata”, via del Politecnico 1, Rome 00133, Italy, via del Politecnico 1.
    Madsen, Morten
    Mads Clausen Institute, Center for Advanced Photovoltaics and Thin Film Energy Devices (SDU CAPE), University of Southern Denmark, Sønderborg 6400, Denmark; SDU Climate Cluster, University of Southern Denmark, Odense 5230, Denmark.
    2D MXene-Based Electron Transport Layers for Nonhalogenated Solvent-Processed Stable Organic Solar Cells2023In: ACS Applied Energy Materials, E-ISSN 2574-0962, Vol. 6, no 9, p. 4549-4558Article in journal (Refereed)
    Abstract [en]

    Implementation of 2D materials is one of the promising routes for improving the efficiency and stability of organic solar cells (OSCs). Due to their tunable optical and electronic properties, MXenes, a family of 2D transition metal carbides and nitrides, have attracted considerable attention and demonstrated their potential for next-generation solar cells. In this work, Ti3C2Tx MXene was added into ZnO precursors and applied as a modified composite electron transport layer (ETL) in PM6:N3-based inverted OSCs. The nonhalogenated solvent o-xylene was employed as the active layer solvent for the development of stable, efficient, and eco-friendly OSCs. By optimizing the concentration of Ti3C2Tx in the ZnO ETL, the solar cells exhibited power conversion efficiencies (PCEs) of 14.1 and 13.7% for 0.5 and 2 wt % MXene, respectively, as compared to neat ZnO layer devices with a PCE of 14.9%. Interestingly, the MXene-based PM6:N3 OSC devices showed superior device stability compared to the reference cells. It is demonstrated that the MXene introduced in the composite ZnO-based ETL mitigates the photocatalytic decomposition of the organic active layer on the ZnO surface, as analyzed via optical spectroscopy and hard X-ray photoelectron spectroscopy, which appears as a main reason for improved device stability. We thus report on the usage of MXene in green solvent-processed OSCs to enhance the lifetime of solar cells and thus address an important bottleneck in high-performance nonfullerene acceptor solar cells.

  • 39.
    Ashour, Radwa
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering. Nuclear Materials Authority, P.O. Box 530, 11381 El Maadi, Cairo, Egypt.
    Samouhos, Michail
    Swedish University of Agricultural Sciences, Department of Molecular Sciences, Uppsala BioCentre.
    Polido Legaria, Elizabeth
    Swedish University of Agricultural Sciences, Department of Molecular Sciences, Uppsala BioCentre.
    Svärd, Michael
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Transport Phenomena.
    Högblom, Joakim
    AkzoNobel, Pulp and Performance Chemicals AB.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Palmlöf, Magnus
    Kessler, Vadim G.
    Swedish University of Agricultural Sciences, Department of Molecular Sciences, Uppsala BioCentre.
    Seisenbaeva, Gulaim A.
    Swedish University of Agricultural Sciences, Department of Molecular Sciences, Uppsala BioCentre.
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    DTPA-Functionalized Silica Nano- and Microparticles for Adsorption and Chromatographic Separation of Rare Earth Elements2018In: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 6, no 5, p. 6889-6900Article in journal (Refereed)
    Abstract [en]

    Silica nanoparticles and porous microparticles have been successfully functionalized with a monolayer of DTPA-derived ligands. The ligand grafting is chemically robust and does not appreciably influence the morphology or the structure of the material. The produced particles exhibit quick kinetics and high capacity for REE adsorption. The feasibility of using the DTPA-functionalized microparticles for chromatographic separation of rare earth elements has been investigated for different sample concentrations, elution modes, eluent concentrations, eluent flow rates, and column temperatures. Good separation of the La(III), Ce(III), Pr(III), Nd(III), and Dy(III) ions was achieved using HNO3 as eluent using a linear concentration gradient from 0 to 0.15 M over 55 min. The long-term performance of the functionalized column has been verified, with very little deterioration recorded over more than 50 experiments. The results of this study demonstrate the potential for using DTPA-functionalized silica particles in a chromatographic process for separating these valuable elements from waste sources, as an environmentally preferable alternative to standard solvent-intensive processes.

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  • 40.
    Ashraf, Shakeel
    et al.
    Mid Sweden Univ, Dept Elect, S-85170 Sundsvall, Sweden..
    Forsberg, Viviane
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Mattsson, Claes G.
    Mid Sweden Univ, Dept Elect, S-85170 Sundsvall, Sweden..
    Thungström, Göran
    Mid Sweden Univ, Dept Elect, S-85170 Sundsvall, Sweden..
    Thermoelectric Properties of n-Type Molybdenum Disulfide (MoS2) Thin Film by Using a Simple Measurement Method2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 21, article id 3521Article in journal (Refereed)
    Abstract [en]

    In this paper, a micrometre thin film of molybdenum disulfide (MoS2) is characterized for thermoelectric properties. The sample was prepared through mechanical exfoliation of a molybdenite crystal. The Seebeck coefficient measurement was performed by generating a temperature gradient across the sample and recording the induced electrical voltage, and for this purpose a simple measurement setup was developed. In the measurement, platinum was utilized as reference material in the electrodes. The Seebeck value of MoS2 was estimated to be approximately -600 mu V/K at a temperature difference of 40 degrees C. The negative sign indicates that the polarity of the material is n-type. For measurement of the thermal conductivity, the sample was sandwiched between the heat source and the heat sink, and a steady-state power of 1.42 W was provided while monitoring the temperature difference across the sample. Based on Fourier's law of conduction, the thermal conductivity of the sample was estimated to be approximately 0.26 Wm(-1) K-. The electrical resistivity was estimated to be 29 Omega cm. The figure of merit of MoS2 was estimated to be 1.99 x 10(-4).

  • 41.
    Asp, Leif E.
    et al.
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg, SE-412 96, Sweden.
    Bouton, Karl
    Carlstedt, David
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg, SE-412 96, Sweden.
    Duan, Shanghong
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg, SE-412 96, Sweden.
    Harnden, Ross
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Johannisson, Wilhelm
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Johansen, Marcus
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg, SE-412 96, Sweden.
    Johansson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Liu, Fang
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg, SE-412 96, Sweden.
    Peuvot, Kevin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Schneider, Lynn Maria
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Xu, Johanna
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg, SE-412 96, Sweden.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    A Structural Battery and its Multifunctional Performance2021In: Advanced Energy and Sustainability Research, E-ISSN 2699-9412, Vol. 2, no 3, article id 2000093Article in journal (Refereed)
    Abstract [en]

    Engineering materials that can store electrical energy in structural load paths can revolutionize lightweight design across transport modes. Stiff and strong batteries that use solid-state electrolytes and resilient electrodes and separators are generally lacking. Herein, a structural battery composite with unprecedented multifunctional performance is demonstrated, featuring an energy density of 24 Wh kg−1 and an elastic modulus of 25 GPa and tensile strength exceeding 300 MPa. The structural battery is made from multifunctional constituents, where reinforcing carbon fibers (CFs) act as electrode and current collector. A structural electrolyte is used for load transfer and ion transport and a glass fiber fabric separates the CF electrode from an aluminum foil-supported lithium–iron–phosphate positive electrode. Equipped with these materials, lighter electrical cars, aircraft, and consumer goods can be pursued.

  • 42.
    Atoufi Najafabadi, Zhaleh
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Development and Tailoring of Low‐Density Cellulose‐Based Structures for Water Treatment2024Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The challenges posed by our limited clean water sources and the well-known global water pollution demand more efficient water purification technologies. Additionally, the increasing environmental awareness has inspired a shift towards eco-friendly and renewable materials and technologies. This thesis is focused on developing effective adsorbent materials from renewable resources to eliminate organic solvents, dyes, and metal ions from water. Cellulose, the most abundant biopolymer in nature, is the main component used to develop new materials in the present study. Its distinctive physical and colloidal properties, in the form of nanocellulose, along with tunable surface chemistry, play key roles in enhancing the effectiveness of the developed materials.

    The primary focus of the first part of the thesis was to develop a molecular layer-by-layer modification technique to customize the surface functionality of cellulose aerogels in a uniform and controlled manner. Through the sequential deposition of diamine and triacid monomers, exceeding lythin polyamide coatings were formed on the cellulose aerogels, altering the surface properties from hydrophilic to hydrophobic. This transformation made them well-suited structures for oil-water separation.

    Following this, a biohybrid aerogel was developed based on cellulose nanofibrils (CNFs) and amyloid nanofibrils (ANFs), the latter derived by heat treatment of β-lactoglobulin proteins. The pH-tunable surface charge of the aerogel, controlled by the amphiphilicity of the protein, allowed for the adsorption of both cationic and anionic contaminants by adjusting the pH of the solutions. Furthermore, the aerogels exhibited remarkable selectivity for lead (II) ions and they could also be regenerated and reused after each adsorption cycle without a significant loss of their adsorption capacity. This was to a large extent possible due to the excellent wet stability of these aerogels, which was achieved by crosslinking the CNFs during freezing and ice templating, eliminating the need for freeze-drying. However, a solvent exchange to acetone after melting was still necessary to reduce the influence of the capillary forces during drying to avoid the collapse of the aerogels. In a consecutive study, the foaming characteristics of the heat-treated β-lactoglobulin system were exploited to create highly stable Pickering foams with the aid of using CNFs as stabilizers and to physically lock the system through a controlled pH reduction. Interestingly, these Pickering foams could be directly oven-dried without collapsing, yielding low-density foams. Furthermore, it was demonstrated that the foams can be chemically crosslinked by incorporating chemical crosslinkers in the formulation or by pre-functionalizing the CNFs with dialdehydes. This crosslinking naturally also provided wet stability to the oven-dried foams.

    Finally, an innovative and environmentally friendly method was introduced to increase the charge of cellulose fibers by radical polymerization of acrylic acid from the fibers, enabling the preparation of fibers with an exceptionally high charge of 6.7 mmol/g. The introduction of these charged groups significantly enhanced the interaction of the fibers with methylene blue as a model dye and lead (II), Copper (II), and Zinc (II) ions as model metal ions, showing the huge potential of these fibers as building blocks for a wide range of adsorbent applications. Overall, this thesis demonstrates the development and characterization of several bio-based adsorbents for water remediation.

  • 43.
    Atoufi, Zhaleh
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Ciftci, Göksu Cinar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Reid, Michael S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Larsson, Per A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Green Ambient-Dried Aerogels with a Facile pH-Tunable Surface Charge for Adsorption of Cationic and Anionic Contaminants with High Selectivity2022In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 23, no 11, p. 4934-4947Article in journal (Refereed)
    Abstract [en]

    The fabrication of reusable, sustainable adsorbents from low-cost, renewable resources via energy efficient methods is challenging. This paper presents wet-stable, carboxymethylated cellulose nanofibril (CNF) and amyloid nanofibril (ANF) based aerogel-like adsorbents prepared through efficient and green processes for the removal of metal ions and dyes from water. The aerogels exhibit tunable densities (18-28 kg m-3), wet resilience, and an interconnected porous structure (99% porosity), with a pH controllable surface charge for adsorption of both cationic (methylene blue and Pb(II)) and anionic (brilliant blue, congo red, and Cr(VI)) model contaminants. The Langmuir saturation adsorption capacity of the aerogel was calculated to be 68, 79, and 42 mg g-1for brilliant blue, Pb(II), and Cr(VI), respectively. Adsorption kinetic studies for the adsorption of brilliant blue as a model contaminant demonstrated that a pseudo-second-order model best fitted the experimental data and that an intraparticle diffusion model suggests that there are three adsorption stages in the adsorption of brilliant blue on the aerogel. Following three cycles of adsorption and regeneration, the aerogels maintained nearly 97 and 96% of their adsorption capacity for methylene blue and Pb(II) as cationic contaminants and 89 and 80% for brilliant blue and Cr(VI) as anionic contaminants. Moreover, the aerogels showed remarkable selectivity for Pb(II) in the presence of calcium and magnesium as background ions, with a selectivity coefficient more than 2 orders of magnitude higher than calcium and magnesium. Overall, the energy-efficient and sustainable fabrication procedure, along with good structural stability, reusability, and selectivity, makes these aerogels very promising for water purification applications.

  • 44.
    Atoufi, Zhaleh
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Gordeyeva, Korneliya
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fiberprocesser.
    Cortes Ruiz, Maria F.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Hall, Stephen A
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Larsson, Per A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Wet-resilient foams based on heat-treated β-lactoglobulin and cellulose nanofibrilsManuscript (preprint) (Other academic)
  • 45.
    Atoufi, Zhaleh
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Gordeyeva, Korneliya
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fiberprocesser.
    Cortes Ruiz, Maria F.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Larsson, Per A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Synergistically stabilized wet foams from heat treated β-lactoglobulin and cellulose nanofibrils and their application for green foam productionManuscript (preprint) (Other academic)
  • 46.
    Atoufi, Zhaleh
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Reid, Michael S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Larsson, Per A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Surface tailoring of cellulose aerogel-like structures with ultrathin coatings using molecular layer-by-layer assembly2022In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 282, article id 119098Article in journal (Refereed)
    Abstract [en]

    Cellulose nanofibril-based aerogels have promising applicability in various fields; however, developing an effi-cient technique to functionalize and tune their surface properties is challenging. In this study, physically and covalently crosslinked cellulose nanofibril-based aerogel-like structures were prepared and modified by a mo-lecular layer-by-layer (m-LBL) deposition method. Following three m-LBL depositions, an ultrathin polyamide layer was formed throughout the aerogel and its structure and chemical composition was studied in detail. Analysis of model cellulose surfaces showed that the thickness of the deposited layer after three m-LBLs was approximately 1 nm. Although the deposited layer was extremely thin, it led to a 2.6-fold increase in the wet specific modulus, improved the acid-base resistance, and changed the aerogels from hydrophilic to hydrophobic making them suitable materials for oil absorption with the absorption capacity of 16-36 g/g. Thus, demon-strating m-LBL assembly is a powerful technique for tailoring surface properties and functionality of cellulose substrates.

  • 47.
    Attarzadeh, Reza
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Attarzadeh-Niaki, Seyed-Hosein
    Shahid Beheshti Univ SBU, Fac Comp Sci & Engn, Tehran, Iran..
    Duwig, Christophe
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Multi-objective optimization of TPMS-based heat exchangers for low-temperature waste heat recovery2022In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 212, p. 118448-, article id 118448Article in journal (Refereed)
    Abstract [en]

    The transformation to a truly sustainable energy system will require taking better advantage of the waste heat. Integrating heat exchangers with the triply periodic minimal surface (TPMS) is a promising and efficient way to build waste heat recovery systems that harness heat emissions from the low pitch thermal systems. This is mainly due to the low hydrodynamic resistance and pressure drop in the TPMS while securing good heat transfer at low-temperature gradient. This study establishes a computational design and analysis of heat and mass transfer inside a heat exchanger based on the TPMS structure and determine thermal effectiveness, heat transfer coefficient, and pressure drop inside the channel. The non-linearity dependence of results to several design variables makes obtaining the optimal design configuration solely using conventional CFD or experimental study nearly impossible. Hence, a multi-objective optimization workflow based on a Genetic Algorithm for laminar flow is employed to reveal the underlying relationships between design variables for the optimal configurations. The results illustrate the local sensitivity of important parameters such as the heat transfer coefficient, Nusselt number, and thermal performance of the heat exchanger against various design variables. It is shown that the pressure drop is directly affected by gas inlet velocity, viscosity, and density, from high to low, respectively. The Pareto frontiers for the optimal thermal performance are extracted, and the correlation between design objectives is determined. This methodology provides a promising framework for heat exchangers' design analysis, including multi-objective goals and design constraints.

  • 48. Aung, S. H.
    et al.
    Zhao, L.
    Nonomura, K.
    Oo, T. Z.
    Zakeeruddin, S. M.
    Vlachopoulos, N.
    Sloboda, Tamara
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Svanström, S.
    Cappel, Ute B.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Hagfeldt, A.
    Grätzel, M.
    Toward an alternative approach for the preparation of low-temperature titanium dioxide blocking underlayers for perovskite solar cells2019In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 17, p. 10729-10738Article in journal (Refereed)
    Abstract [en]

    The anodic electrodeposition method is investigated as an alternative technique for the preparation of a titanium oxide (TiO 2 ) blocking underlayer (UL) for perovskite solar cells (PSCs). Extremely thin Ti IV -based films are grown from aqueous acidic titanium(iii) chloride in an electrochemical cell at room temperature. This precursor layer is converted to the UL (ED-UL), in a suitable state for PSC applications, by undertaking a sintering step at 450 °C for half an hour. PSCs with the composition of the light-absorbing material FA 0.85 MA 0.10 Cs 0.05 Pb(I 0.87 Br 0.13 ) 3 (FA and MA denote the formamidinium and methylammonium cations, respectively) based on the ED-UL are compared with PSCs with the UL of a standard type prepared by the spray-pyrolysis method at 450 °C from titanium diisopropoxide bis(acetylacetonate) (SP-UL). We obtain power conversion efficiencies (PCEs) of over 20% for mesoscopic perovskite devices employing both ED-ULs and SP-ULs. Slightly higher fill factor values are observed for ED-UL-based devices. In addition, ED-ULs prepared by the same method have also been applied in planar PSCs, resulting in a PCE exceeding 17%, which is comparable to that for similar PSCs with an SP-UL. The preparation of ED-ULs with a lower sintering temperature, 150 °C, has also been examined. The efficiency of a planar PSC incorporating this underlayer was 14%. These results point out to the possibility of applying ED-ULs in flexible planar PSCs in the future.

  • 49. Aydin, M.
    et al.
    Unal, B.
    Esat, B.
    Baykal, A.
    Karaoglu, E.
    Toprak, Muhammet Sadaka
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Sozeri, H.
    Synthesis, magnetic and electrical characteristics of poly(2-thiophen-3-yl-malonic acid)/Fe(3)O(4) nanocomposite2012In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 514, p. 45-53Article in journal (Refereed)
    Abstract [en]

    Poly(2-thiophen-3-yl-malonic acid)/Fe(3)O(4) nanocomposite was synthesized by the precipitation of Fe(3)O(4) in the presence of poly(2-thiophen-3-yl-malonic acid) (PT3MA). Characterizations of the nanocomposite were performed by XRD, FT-IR, TEM, TGA, AC/DC conductivity and dielectric measurements. The capping of PT3MA around Fe(3)O(4) nanoparticles was confirmed by FTIR spectroscopy, the interaction being between bridging oxygen of the carboxylate and the nanoparticle surface through bidentate binding. The crystallite particle sizes of 6 +/- 3 nm and 7 +/- 3 nm were obtained from XRD line profile fitting and from TEM image analysis respectively, and they are in good agreement with each other. Magnetization measurements revealed that PT3MA coated magnetite particles do not saturate at higher fields. The material showed superparamagnetic character as revealed by the absence of coercivity and remnant magnetization. Magnetic particle size was calculated as 7.3 +/- 1.0 nm from the mean magnetization term in the Langevin function which is also in conformity with the values determined from TEM micrographs and XRD line profile fitting. The TEM particle size analysis of the nanoparticles revealed the presence of a slightly modified magnetically dead nanoparticle surface. AC and DC conductivity measurements were performed to elucidate the electrical conduction characteristics of the product.

  • 50. Ayedh, H. M.
    et al.
    Bathen, M. E.
    Galeckas, A.
    Hassan, J. U.
    Bergman, J. P.
    Nipoti, R.
    Hallén, Anders
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electronics and Embedded systems, Integrated devices and circuits.
    Svensson, B. G.
    Controlling the carbon vacancy in 4H-SiC by thermal processing2018In: ECS Transactions, Electrochemical Society Inc. , 2018, no 12, p. 91-97Conference paper (Refereed)
    Abstract [en]

    The carbon vacancy (Vc) is perhaps the most prominent point defect in silicon carbide (SiC) and it is an efficient charge carrier lifetime killer in high-purity epitaxial layers of 4H-SÌC. The Vc concentration needs to be controlled and minimized for optimum materials and device performance, and an approach based on post-growth thermal processing under C-rich ambient conditions is presented. It utilizes thermodynamic equilibration and after heat treatment at 1500 °C for 1 h, the Vc concentration is shown to be reduced by a factor-25 relative to that in as-grown state-of-the-art epi-layers. Concurrently, a considerable enhancement of the carrier lifetime occurs throughout the whole of >40 urn thick epi-layers. 

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