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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 composites2018Inngår i: Journal of materials science. Materials in electronics, ISSN 0957-4522, E-ISSN 1573-482X, Vol. 29, nr 4, s. 2848-2859Artikkel i tidsskrift (Fagfellevurdert)
    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. Aaldering, L. J.
    et al.
    Poongavanam, V.
    Langkjær, N.
    Natarajan Arul, Murugan
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Jørgensen, P. T.
    Wengel, J.
    Veedu, R. N.
    Development of an Efficient G-Quadruplex-Stabilised Thrombin-Binding Aptamer Containing a Three-Carbon Spacer Molecule2017Inngår i: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 18, nr 8, s. 755-763Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The thrombin-binding aptamer (TBA), which shows anticoagulant properties, is one of the most studied G-quadruplex-forming aptamers. In this study, we investigated the impact of different chemical modifications such as a three-carbon spacer (spacer-C3), unlocked nucleic acid (UNA) and 3′-amino-modified UNA (amino-UNA) on the structural dynamics and stability of TBA. All three modifications were incorporated at three different loop positions (T3, T7, T12) of the TBA G-quadruplex structure to result in a series of TBA variants and their stability was studied by thermal denaturation; folding was studied by circular dichroism spectroscopy and thrombin clotting time. The results showed that spacer-C3 introduction at the T7 loop position (TBA-SP7) significantly improved stability and thrombin clotting time while maintaining a similar binding affinity as TBA to thrombin. Detailed molecular modelling experiments provided novel insights into the experimental observations, further supporting the efficacy of TBA-SP7. The results of this study could provide valuable information for future designs of TBA analogues with superior thrombin inhibition properties. 

  • 3. Aas, Wenche
    et al.
    Szabo, Zoltan
    KTH, Tidigare Institutioner (före 2005), Kemi.
    Grenthe, Ingmar
    KTH, Tidigare Institutioner (före 2005), Kemi.
    Equilibria and dynamics in binary and ternary uranyl oxalate and acetate/fluoride complexes1999Inngår i: Journal of the Chemical Society - Dalton Transactions, ISSN 0300-9246, nr 8, s. 1311-1317Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The formation of ternary UO2(ac)pFq2-p-q (p = 1 or 2 and q = 1-3) complexes, and their equilibrium constants were investigated by potentiometric titrations and 19F NMR spectroscopy. The equilibrium constants have been determined from the emf data in a NaClO4 medium at constant sodium concentration, [Na+] = 1.00 M at 25°C, except for the UO2(ac)F32- complex where 19F NMR at -5°C was used. The magnitude of the equilibrium constant for the stepwise addition of fluoride indicates that prior co-ordination of acetate has only a small effect on the subsequent bonding of fluoride. The acetate exchange in the ternary UO2(ac)F32- complex was studied using 19F NMR. Through magnetisation transfer experiments, it was possible to confirm the provisional mechanism from a previous study and also the consistency of the rate constants for the five different exchange pathways required to describe the fluoride exchange. The exchange takes place via the intermediate UO2F3(H2O)2-, indicating that the acetate exchange follows an interchange mechanism with solvent participation in the transition state. The rates and mechanisms of the ligand exchange reactions in UO2(ox)2(H2O)2- and UO2(ac)2(H2O) have been studied using 13C NMR techniques at -5°C. The rate law is v = k-[complex][ligand], and the second order rate constant and the activation parameters for both systems have been determined. The reactions most likely take place through an Eigen-Wilkins type of mechanism, where the first step is a pre-equilibrium of an outer-sphere complex followed by a rate determining exchange of water. The rate constants for the water exchange reactions are very similar to that in UO2(H2O)52+. The information from the binary oxalate system rules out the formation of UO2(ox)2(H2O)2- as an intermediate in the exchange reactions in the previously studied UO2(ox)2F3-, also in this case confirming a previously suggested exchange mechanism. The H+/D+ isotope effects and a linear free energy relationship suggest that the main catalytic effect of H+ on ligand exchange rates is due to the formation of a protonated precursor. Hence, the catalytic effect depends on the basicity of the ligand and the site for the proton attack.

  • 4.
    Abada, Maria
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Spent Nuclear Fuel under Repository Conditions: Update and Expansion of Database and Development of Machine Learning Models2022Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Förbrukat kärnbränsle är mycket radioaktivt och behöver därför lagras i djupa geologiska förvar i tusentals år innan det säkert kan återföras till naturen. På grund av de långa lagringsperioderna görs säkerhetsanalyser av de djupa geologiska förvaren. Under säkerthetsanalyserna görs upplösningsexperiment på förbrukat kärnsbränsle för att utvärdera konsekvenserna av att grundvatten läcker in i bränslet vid barriärbrott. Dessa experiment är både dyra och tidskrävande, varför beräkningsmodeller som kan förutsäga förburkat kärnbränsles upplösningsbeteende är önskvärda.

    Denna avhandling fokuserar på att samla in tillgängliga experimentella data från upplösningsexperiment för att uppdatera och utöka en databas. Med hjälp av databasen har upplösningsbeteendet för varje radionuklid utvärderats och jämförts med tidigare kunskap från befintlig litteratur. Även om det var svårt att vara avgörande om beteendet hos element där en begränsad mängd data fanns tillgänglig, motsvarar de upplösningsbeteenden som hittats för olika radionuklider i denna avhandling inte bara tidigare studier utan ger också ett verktyg för att hantera och jämföra förbrukat kärnbränsles upplösningsdata från olika utgångsmaterial, bestrålningshistorik och betingeleser under upplösning. Dessutom gjorde sammanställningen av en så stor mängd experimentella data det möjligt att förstå var framtida experimentella ansträngningar bör fokuseras, exempelvis finns det en brist på data under reducerande förhållanden.

    Dessutom utvecklades och kördes maskininlärningsmodeller med hjälp av Artificial Neural Network (ANN), Random Forest (RF) och XGBoost-algoritmer med hjälp av databasen, varefter prestandan utvärderades. Prestanda för varje algoritm jämfördes för att få en förståelse för vilken modell som presterade bäst, men också för att förstå om dessa typer av modeller är lämpliga verktyg för att förutspå förbrukat kärnbränsles upplösningsbeteende. Den bäst presterande modellen, med träning och test R2 resultat nära 1, var XGBoost-modellen. Även om XGBoost hade en hög prestanda, drogs slutsatsen att mer experimentell data behövs innan maskininlärningsmodeller kan användas i verkliga situationer.

    Fulltekst (pdf)
    fulltext
  • 5.
    Abada, Maria
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Fossum, Elin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Brandt, Louise
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Åkesson, Anton
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Property prediction of super-strong nanocellulose fibers2020Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The innovative technology behind production of strong biofilaments involves the process of spinning filaments from nanoparticles extracted from wood. These nanoparticles are called cellulose nanofibrils (CNFs). The spun filaments can have high mechanical properties, rivaling many other plant based materials, and could be an environmentally friendly replacement for many materials in the future such as fabrics and composites. Before mass production might be possible, the optimal dispersion properties must be determined for the intended use, with regard to concentration, method of oxidation (TEMPO-oxidation or carboxymethylation) and pretreatment through sonication and centrifugation.

    In this bachelor’s thesis attributes of spun filaments were investigated in order to find a correlation between mechanical properties and the effects of concentration, method of oxidation as well as sonication and centrifugation of the dispersions. The mechanical properties were also compared to the fibrils’ ability to entangle and align during flow-focusing. A variety of analytical methods: flow-stop, tensile testing, scanning electron microscopy (SEM) and wide angle X-ray scattering (WAXS) were implemented for the dispersions and filaments.

    The results from this study show that flow-stop analysis could be used to determine which CNF dispersions are spinnable and which are non-spinnable, along with which spinnable dispersion would yield the strongest filament. It was also concluded that crystallinity of fibrils affects the mechanical properties of filaments and that TCNFs are generally more crystalline than CMCs. Pretreatment through sonication and centrifugation seems to have a negative impact on spinnability and sonication in combination with low concentration seems to lead to non-spinnable conditions. On the other hand, sonicated dispersions seem to yield a greater number of samples without aggregates than non-sonicated ones. Aggregates, however, seem to only affect ultimate stress out of the measured mechanical properties. Furthermore, concentration and viscosity affect spinnability and CMC dispersions seem to yield thicker filaments than TCNF dispersions. However, due to lack of statistically validated data any definitive conclusions could not be drawn.

    Fulltekst (pdf)
    fulltext
  • 6.
    Abbadessa, Anna
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Oinonen, Petri
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Ecohelix AB, Teknikringen 38, SE-10044 Stockholm, Sweden..
    Henriksson, Gunnar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Characterization of Two Novel Bio-based Materials from Pulping Process Side Streams: Ecohelix and CleanFlow Black Lignin2018Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 13, nr 4, s. 7606-7627Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 7.
    Abbasi Aval, Negar
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi. Isfahan Univ Technol, Dept Mat Engn, Biomat Res Grp, Esfahan 8475683777, Iran.;Isfahan Univ Med Sci, Sch Med, Dept Anat Sci, Esfahan, Iran..
    Emadi, Rahmatollah
    Isfahan Univ Technol, Dept Mat Engn, Biomat Res Grp, Esfahan 8475683777, Iran..
    Valiani, Ali
    Isfahan Univ Med Sci, Sch Med, Dept Anat Sci, Esfahan, Iran..
    Kharaziha, Mahshid
    Isfahan Univ Technol, Dept Mat Engn, Biomat Res Grp, Esfahan 8475683777, Iran..
    Finne Wistrand, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    An aligned fibrous and thermosensitive hyaluronic acid-puramatrix interpenetrating polymer network hydrogel with mechanical properties adjusted for neural tissue2022Inngår i: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 57, nr 4, s. 2883-2896Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Central nervous system (CNS) injuries such as stroke or trauma can lead to long-lasting disability, and there is no currently accepted treatment to regenerate functional CNS tissue after injury. Hydrogels can mimic the neural extracellular matrix by providing a suitable 3D structure and mechanical properties and have shown great promise in CNS tissue regeneration. Here we present successful synthesis of a thermosensitive hyaluronic acid-RADA 16 (Puramatrix (TM)) peptide interpenetrating network (IPN) that can be applied in situ by injection. Thermosensitive hyaluronic acid (HA) was first synthesized by combining HA with poly(N-isopropylacrylamide). Then, the Puramatrix (TM) self-assembled peptide was combined with the thermosensitive HA to produce a series of injectable thermoresponsive IPNs. The HA-Puramatrix (TM) IPNs formed hydrogels successfully at physiological temperature. Characterization by SEM, rheological measurements, enzymatic degradation and swelling tests was performed to select the IPN optimized for neurologic use. SEM images of the optimized dry IPNs demonstrated an aligned porous structure, and the rheological measurements showed that the hydrogels were elastic, with an elastic modulus of approximately 500 Pa, similar to that of brain tissue. An evaluation of the cell-material interactions also showed that the IPN had biological characteristics required for tissue engineering, strongly suggesting that the IPN hydrogel possessed properties beneficial for regeneration of brain tissue.

  • 8.
    Abbasi, M.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Backstrom, J.
    Mid Sweden Univ, FSCN Mat Phys, Dept Nat Sci, SE-85170 Sundsvall, Sweden..
    Cornell, Ann M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Fabrication of Spin-Coated Ti/TiHx/Ni-Sb-SnO2 Electrode: Stability and Electrocatalytic Activity2018Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 165, nr 9, s. H568-H574Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 9.
    Abdel Alim, Richard
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Formation of Soft Particles in Drop-in Fuels2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

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

    Fulltekst (pdf)
    fulltext
  • 10.
    Abdelaziz, Omar Y.
    et al.
    Department of Chemical Engineering, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia; Interdisciplinary Research Center for Refining & Advanced Chemicals, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia.
    Vives, Mariona Battestini
    Division of Chemical Engineering, Department of Process and Life Science Engineering, Lund University, SE-221 00 Lund, Sweden.
    Mankar, Smita V.
    Centre for Analysis and Synthesis, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden.
    Warlin, Niklas
    Centre for Analysis and Synthesis, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden; Department of Chemistry, Stanford University, Stanford, California 94306, United States.
    Nguyen, Tran Tam
    Centre for Analysis and Synthesis, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden.
    Zhang, Baozhong
    Centre for Analysis and Synthesis, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden.
    Hulteberg, Christian P.
    Division of Chemical Engineering, Department of Process and Life Science Engineering, Lund University, SE-221 00 Lund, Sweden.
    khataee, Amirreza
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Recent strides toward transforming lignin into plastics and aqueous electrolytes for flow batteries2024Inngår i: iScience, E-ISSN 2589-0042, Vol. 27, nr 4, artikkel-id 109418Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Lignin is an abundant polyaromatic polymer with a wide range of potential future uses. However, the conversion of lignin into valuable products comes at a cost, and medium- to high-value applications are thus appropriate. Two examples of these are polymers (e.g., as fibers, plasticizers, or additives) and flow batteries (e.g., as redox species). Both of these areas would benefit from lignin-derived molecules with potentially low molecular weight and high (electro)chemical functionality. A promising route to obtain these molecules is oxidative lignin depolymerization, as it enables the formation of targeted compounds with multiple functionalities. An application with high potential in the production of plastics is the synthesis of new sustainable polymers. Employing organic molecules, such as quinones and heterocycles, would constitute an important step toward the sustainability of aqueous flow batteries, and lignin and its derivatives are emerging as redox species, mainly due to their low cost and renewability.

  • 11. Abdel-Khalek, Ahmed A.
    et al.
    Ali, M. M.
    Ashour, Radwa
    Abdel-Magied, A. F.
    Chemical Studies on Uranium Extraction from Concentrated Phosphoric Acid by Using PC88A and DBBP Mixture.2011Inngår i: Journal of Radioanalytical and Nuclear Chemistry, ISSN 0236-5731, E-ISSN 1588-2780, Vol. 290, s. 353-359Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Liquid–liquid extraction of U (VI) from concentrated phosphoric acid by using (2-ethyl hexyl) phosphonic acid, mono (2-ethyl hexyl) ester (PC88A) and di-butyl butyl phosphonate (DBBP) has been investigated. The effect of different factors affecting the extraction process (PC88A concentration, DBBP concentration, shaking time, aqueous/organic phase ratio, phosphoric acid concentration and effect of diluents) have been investigated. The obtained data of temperature on the extraction showed that the enthalpy change is −17.15 kJ mol−1. Uranium was extracted from the strip liquor by using di (2-ethylhexyl) phosphoric acid and tri-octyl phosphine oxide mixture and finally converted to a high purity UO3 product using precipitation with hydrogen peroxide and heat treatment at 365 °C.

  • 12. Abdellah, Mohamed
    et al.
    Zhang, Shihuai
    Wang, Mei
    Hammarstrom, Leif
    Competitive Hole Transfer from CdSe Quantum Dots to Thiol Ligands in CdSe-Cobaloxime Sensitized NiO Films Used as Photocathodes for H-2 Evolution2017Inngår i: ACS Energy Letters, E-ISSN 2380-8195, Vol. 2, nr 11, s. 2576-2580Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Quantum dot (QD) sensitized NiO photocathodes rely on efficient photoinduced hole injection into the NiO valence band. A system of a mesoporous NiO film co-sensitized with CdSe QDs and a molecular proton reduction catalyst was studied. While successful electron transfer from the excited QDs to the catalyst is observed, most of the photogenerated holes are instead quenched very rapidly (ps) by hole trapping at the surface thiols of the capping agent used as linker molecules. We confirmed our conclusion by first using a thiol free capping agent and second varying the thiol concentration on the QD's surface. The later resulted in faster hole trapping as the thiol concentration increased. We suggest that this hole trapping by the linker limits the H-2 yield for this photocathode in a device.

  • 13.
    Abdel-Rehim, Mohamed
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet.
    Pedersen-Bjergaard, S.
    Abdel-Rehim, A.
    Lucena, R.
    Moein, M. M.
    Cárdenas, S.
    Miró, M.
    Microextraction approaches for bioanalytical applications: An overview2020Inngår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1616, artikkel-id 460790Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biological samples are usually complex matrices due to the presence of proteins, salts and a variety of organic compounds with chemical properties similar to those of the target analytes. Therefore, sample preparation is often mandatory in order to isolate the analytes from troublesome matrices before instrumental analysis. Because the number of samples in drug development, doping analysis, forensic science, toxicological analysis, and preclinical and clinical assays is steadily increasing, novel high throughput sample preparation approaches are calling for. The key factors in this development are the miniaturization and the automation of the sample preparation approaches so as to cope with most of the twelve principles of green chemistry. In this review, recent trends in sample preparation and novel strategies will be discussed in detail with particular focus on sorptive and liquid-phase microextraction in bioanalysis. The actual applicability of selective sorbents is also considered. Additionally, the role of 3D printing in microextraction for bioanalytical methods will be pinpointed.

  • 14.
    Abdi, Adel Hirmand
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Key aspects in winter highway operation and maintenance2010Rapport (Annet vitenskapelig)
  • 15.
    Abedin, Ahmad
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektronik och inbyggda system.
    Zurauskaite, Laura
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektronik och inbyggda system.
    Asadollahi, Ali
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektronik och inbyggda system.
    Garidis, Konstantinos
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektronik och inbyggda system.
    Jayakumar, Ganesh
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektronik och inbyggda system.
    Malm, B. Gunnar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektronik och inbyggda system.
    Hellström, Per-Erik
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektronik och inbyggda system.
    Östling, Mikael
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Germanium on Insulator Fabrication for Monolithic 3-D Integration2018Inngår i: IEEE Journal of the Electron Devices Society, E-ISSN 2168-6734, Vol. 6, nr 1, s. 588-593Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 16.
    Abellan-Flos, Marta
    et al.
    Univ Namur, Dept Chim, Lab Chim Bioorgan, Rue Bruxelles 61, B-5000 Namur, Belgium.;PSL Univ, CNRS, ESPCI Paris, Mol Macromol Chem & Mat, 10 Rue Vauquelin, F-75005 Paris, France..
    Timmer, Brian J. J.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Altun, Samuel
    Attana AB, Bjornnasvagen 21, S-11419 Stockholm, Sweden..
    Aastrup, Teodor
    Attana AB, Bjornnasvagen 21, S-11419 Stockholm, Sweden..
    Vincent, Stephane P.
    Univ Namur, Dept Chim, Lab Chim Bioorgan, Rue Bruxelles 61, B-5000 Namur, Belgium..
    Ramström, Olof
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi. Univ Massachusetts, Dept Chem, One Univ Ave, Lowell, MA 01854 USA.;Linnaeus Univ, Dept Chem & Biomed Sci, SE-39182 Kalmar, Sweden..
    QCM sensing of multivalent interactions between lectins and well-defined glycosylated nanoplatforms2019Inngår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 139, artikkel-id 111328Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Quartz crystal microbalance (QCM) methodology has been adopted to unravel important factors contributing to the "cluster glycoside effect" observed in carbohydrate-lectin interactions. Well-defined, glycosylated nanostructures of precise sizes, geometries and functionalization patterns were designed and synthesized, and applied to analysis of the interaction kinetics and thermodynamics with immobilized lectins. The nanostructures were based on Borromean rings, dodecaamine cages, and fullerenes, each of which carrying a defined number of carbohydrate ligands at precise locations. The synthesis of the Borromeates and dodecaamine cages was easily adjustable due to the modular assembly of the structures, resulting in variations in presentation mode. The binding properties of the glycosylated nanoplatforms were evaluated using flow-through QCM technology, as well as hemagglutination inhibition assays, and compared with dodecaglycosylated fullerenes and a monovalent reference. With the QCM setup, the association and dissociation rate constants and the associated equilibrium constants of the interactions could be estimated, and the results used to delineate the multivalency effects of the lectin-nanostructure interactions.

  • 17.
    Abili Nejad, Maryam
    KTH, Tidigare Institutioner (före 2005), Kemi.
    Kinetics for oxidation of CRUD model compounds2004Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The formation of CRUD (Chalk River Unidentified Deposit) inwater-cooled nuclear reactors constitute a severe problem. Thestability of CRUD under reactor conditions (high flux ofionizing radition, high temperature and pressure) must be knownin order to minimize the problem. The kinetics for CRUDoxidation by H2O2 and the two more potent oxidants IrCl62-and MnO4- has been studied using aqueous suspensions ofthree metal oxide powders, Fe3O4, Fe2CoO4 and Fe2NiO4. The metal oxides were used as model compounds forCRUD. The latter two oxidants were employed to study therelationship between kinetics and the reduction potential ofthe oxidant. In addition, the activation energies for thereaction between H2O2and the three metal oxides of CRUD model weredetermined. The mechanism of the reaction is discussedindicating that the final solid product in all three cases isFe2O3. Our experimental results show that the reactivityof the metal oxides towards oxidants is in the order Fe2CoO4>Fe3O4>Fe2NiO4. The relative reactivities of Fe2CoO4 and Fe3O4are in contrast with that expected from the studyof the ionization potentials of the divalent metals in theoxides. In addition to the experimental studies, thetheoretical grounds for kinetics of reactions in particlesolutions are discussed. The theoretical discussion is alsoused to explain the somewhat unexpected trends in reactivityobserved experimentally. The same reaction trend is alsoobserved in the reaction of the metal oxides with IrCl62-and MnO4-.

    We found experimentally that the logarithm of second orderrate constants of the reaction of metal oxides with oxidantsagainst the one electron potential of the oxidants follows aparabolic behavior in agreement with the Marcus theory forelectron transfer reactions. This work constitutes a good basisfor the design of further model studies aiming at resolving thestability of CRUD under reactor conditions.

    Keywords:Reactor Chemistry, Radiolysis, Oxidation,Kinetics, CRUD, Metal oxide

  • 18. Abitbol, T.
    et al.
    Ahniyaz, A.
    Álvarez-Asencio, R.
    Fall, A.
    Swerin, Agne
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Nanocellulose-Based Hybrid Materials for UV Blocking and Mechanically Robust Barriers2020Inngår i: ACS Applied Bio Materials, E-ISSN 2576-6422, Vol. 3, nr 4, s. 2245-2254Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanocellulose (NC)-based hybrid coatings and films containing CeO2 and SiO2 nanoparticles (NPs) to impart UV screening and hardness properties, respectively, were prepared by solvent casting. The NC film-forming component (75 wt % of the overall solids) was composed entirely of cellulose nanocrystals (CNCs) or of CNCs combined with cellulose nanofibrils (CNFs). Zeta potential measurements indicated that the four NP types (CNC, CNF, CeO2, and SiO2) were stably dispersed in water and negatively charged at pH values between 6 and 9. The combination of NPs within this pH range ensured uniform formulations and homogeneous coatings and films, which blocked UV light, the extent of which depended on film thickness and CeO2 NP content, while maintaining good transparency in the visible spectrum (∼80%). The addition of a low amount of CNFs (1%) reduced the film hardness, but this effect was compensated by the addition of SiO2 NPs. Chiral nematic self-assembly was observed in the mixed NC film; however, this ordering was disrupted by the addition of the oxide NPs. The roughness of the hybrid coatings was reduced by the inclusion of oxide NPs into the NC matrix perhaps because the spherical oxide NPs were able to pack into the spaces between cellulose fibrils. We envision these hybrid coatings and films in barrier applications, photovoltaics, cosmetic formulations, such as sunscreens, and for the care and maintenance of wood and glass surfaces, or other surfaces that require a smooth, hard, and transparent finish and protection from UV damage.

  • 19.
    Abraham, Mark J
    Computational Proteomics Group, John Curtin School of Medical Research, Australian National University, Australia.
    Performance enhancements for GROMACS nonbonded interactions on BlueGene.2011Inngår i: Journal of Computational Chemistry, ISSN 0192-8651, E-ISSN 1096-987X, Vol. 32, nr 9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Several improvements to the previously optimized GROMACS BlueGene inner loops that evaluate nonbonded interactions in molecular dynamics simulations are presented. The new improvements yielded an 11% decrease in running time for both PME and other kinds of GROMACS simulations that use nonbonded table look-ups. Some other GROMACS simulations will show a small gain.

  • 20.
    Abraham, Mark J
    et al.
    Australian National University, Australia.
    Gready, Jill E
    Australian National University.
    Ensuring Mixing Efficiency of Replica-Exchange Molecular Dynamics Simulations2008Inngår i: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 4, nr 7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We address the question of constructing a protocol for replica-exchange molecular dynamics (REMD) simulations that make efficient use of the replica space, assess whether published applications are achieving such "mixing" efficiency, and provide a how-to guide to assist users to plan efficient REMD simulations. To address our first question, we introduce and discuss three metrics for assessing the number of replica-exchange attempts required to justify the use of a replica scheme and define a "transit number" as the lower bound for the length of an efficient simulation. Our literature survey of applications of REMD simulations of peptides in explicit solvent indicated that authors are not routinely reporting sufficient details of their simulation protocols to allow readers to make independent assessments of the impact of the method on their results, particularly whether mixing efficiency has been achieved. Necessary details include the expected or observed replica-exchange probability, together with the total number of exchange attempts, the exchange period, and estimates of the autocorrelation time of the potential energy. Our analysis of cases where the necessary information was reported suggests that in many of these simulations there are insufficient exchanges attempted or an insufficiently long period between them to provide confidence that the simulation length justifies the size of the replica scheme. We suggest guidelines for designing REMD simulation protocols to ensure mixing efficiency. Two key recommendations are that the exchange period should in general be larger than 1 ps and the number of exchange attempts should be chosen to significantly exceed the transit number for the replica scheme.

  • 21.
    Abraham, Mark J
    et al.
    Australian National University, Australia.
    Gready, Jill E
    Optimization of parameters for molecular dynamics simulation using smooth particle-mesh Ewald in GROMACS 4.52011Inngår i: Journal of Computational Chemistry, ISSN 0192-8651, E-ISSN 1096-987X, Vol. 32, nr 9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Based on our critique of requirements for performing an efficient molecular dynamics simulation with the particle-mesh Ewald (PME) implementation in GROMACS 4.5, we present a computational tool to enable the discovery of parameters that produce a given accuracy in the PME approximation of the full electrostatics. Calculations on two parallel computers with different processor and communication structures showed that a given accuracy can be attained over a range of parameter space, and that the attributes of the hardware and simulation system control which parameter sets are optimal. This information can be used to find the fastest available PME parameter sets that achieve a given accuracy. We hope that this tool will stimulate future work to assess the impact of the quality of the PME approximation on simulation outcomes, particularly with regard to the trade-off between cost and scientific reliability in biomolecular applications.

  • 22.
    Abrahamsson, Anders
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Prediction of Detonation Performance of CHNO Explosives2022Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Produktion av nya energetiska material är dyrt. Målet med detta arbete är att utveckla en metod som uppskattar Chapman-Jouget detonationstrycket och detonationshastigheten hos nya CHNO-sprängämnen. En sådan metod möjliggör valet att bara syntetisera och testa de mest lovande kandidaterna som nya energetiska material, därmed undviks resursslösande arbete. Den här metoden använder sig av density functional theory (DFT) och den elektrostatiska potentialen till att uppskatta bildningsentalpier och kristalldensiteter. Beräkningarna gjordes på traditionella sprängämnen och de beräknade detonationstrycken och detonatioshastigheterna visade bra överensstämmelse med experimentell data. Detonationstrycken hamnade inom ±10% och detonatioshastigheterna inom ±5% av experimentell data.

    Fulltekst (pdf)
    fulltext
  • 23. Abrahamsson, Christoffer
    et al.
    Nordstierna, Lars
    Nordin, Matias
    Dvinskikh, Sergey V.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi. St. Petersburg State University, Russian Federation.
    Nyden, Magnus
    Magnetic orientation of nontronite clay in aqueous dispersions and its effect on water diffusion2015Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 437, s. 205-210Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The diffusion rate of water in dilute clay dispersions depends on particle concentration, size, shape, aggregation and water-particle interactions. As nontronite clay particles magnetically align parallel to the magnetic field, directional self-diffusion anisotropy can be created within such dispersion. Here we study water diffusion in exfoliated nontronite clay dispersions by diffusion NMR and time-dependant 1H-NMR-imaging profiles. The dispersion clay concentration was varied between 0.3 and 0.7 vol%. After magnetic alignment of the clay particles in these dispersions a maximum difference of 20% was measured between the parallel and perpendicular self-diffusion coefficients in the dispersion with 0.7 vol% clay. A method was developed to measure water diffusion within the dispersion in the absence of a magnetic field (random clay orientation) as this is not possible with standard diffusion NMR. However, no significant difference in self-diffusion coefficient between random and aligned dispersions could be observed.

  • 24.
    Abreu, Barbara
    et al.
    Univ Porto, Fac Sci, Dept Chem & Biochem, CIQUP, Rua Campo Alegre, P-4169007 Porto, Portugal..
    Rocha, Jessica
    Univ Porto, Fac Sci, Dept Chem & Biochem, CIQUP, Rua Campo Alegre, P-4169007 Porto, Portugal..
    Ferreira Fernandes, Ricardo Manuel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Regev, Oren
    Ben Gurion Univ Negev, Dept Chem Engn, IL-84105 Beer Sheva, Israel.;Ben Gurion Univ Negev, Ilse Katz Inst Nanotechnol, IL-84105 Beer Sheva, Israel..
    Furo, Istvan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Marques, Eduardo F.
    Univ Porto, Fac Sci, Dept Chem & Biochem, CIQUP, Rua Campo Alegre, P-4169007 Porto, Portugal..
    Gemini surfactants as efficient dispersants of multiwalled carbon nanotubes: Interplay of molecular parameters on nanotube dispersibility and debundling2019Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 547, s. 69-77Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Surfactants have been widely employed to debundle, disperse and stabilize carbon nanotubes in aqueous solvents. Yet, a thorough understanding of the dispersing mechanisms at molecular level is still warranted. Herein, we investigated the influence of the molecular structure of gemini surfactants on the dispersibility of multiwalled carbon nanotubes (MWNTs). We used dicationic n-s-n gemini surfactants, varying n and s, the number of alkyl tail and alkyl spacer carbons, respectively; for comparisons, single-tailed surfactant homologues were also studied. Detailed curves of dispersed MWNT concentration vs. surfactant concentration were obtained through a stringently controlled experimental procedure, allowing for molecular insight. The gemini are found to be much more efficient dispersants than their single-tailed homologues, i.e. lower surfactant concentration is needed to attain the maximum dispersed MWNT concentration. In general, the spacer length has a comparatively higher influence on the dispersing efficiency than the tail length. Further, scanning electron microscopy imaging shows a sizeable degree of MWNT debundling by the gemini surfactants in the obtained dispersions. Our observations also point to an adsorption process that does not entail the formation of micelle-like aggregates on the nanotube surface, but rather coverage by individual molecules, among which the ones that seem to be able to adapt best to the nanotube surface provide the highest efficiency. These studies are relevant for the rational design and choice of optimal dispersants for carbon nanomaterials and other similarly water-insoluble materials.

  • 25. Acciaro, Roberta
    et al.
    Aulin, Christian
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi.
    Lindström, Tom
    Claesson, Per M.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Varga, Imre
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Investigation of the formation, structure and release characteristics of self-assembled composite films of cellulose nanofibrils and temperature responsive microgels2011Inngår i: Soft Matter, ISSN 1744-683X, Vol. 7, nr 4, s. 1369-1377Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The possibility of forming self-organized films using charge-stabilized dispersions of cellulose I nanofibrils and microgel beads of poly-(N-isopropylacrylamide-co-acrylic acid) copolymer is presented. The build-up behavior and the properties of the layer-by-layer (LbL)-constructed films were studied using quartz crystal microbalance with dissipation (QCM-D) and ellipsometry. The morphology of the formed films was also characterized using atomic force microscopy (AFM) imaging. The applied methods clearly demonstrated the successful LbL-assembly of the monodisperse microgels and nanofibrils. The in situ QCM-D measurements also revealed that contrary to the polyelectrolyte bound microgel particles, the nanofibrils-bound gel beads preserve their highly swollen state and do not suffer a partial collapse due to the lack of interdigitation of the oppositely charged components. To probe the accessibility of the gel beads in the formed films, the room temperature (similar to 25 degrees C) loading and release of a fluorescent dye (FITC) was also investigated. The incorporation of the cellulose nanofibrils into the multilayer resulted in an open structure that was found easily penetrable for the dye molecules even at constant room temperature, which is in sharp contrast with previously reported systems based on synthetic polyelectrolytes. The amount of dye released from the multilayer films could be fine-tuned with the number of bilayers. Finally, the thermoresponsivity of the films was also shown by triggering the burst release of the loaded dye when the film was collapsed.

  • 26. Adamus, Grazyna
    et al.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Höglund, Anders
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Kowalczuk, Marek
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    MALDI-TOF MS Reveals the Molecular Level Structures of Different Hydrophilic-Hydrophobic Polyether-esters2009Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 10, nr 6, s. 1540-1546Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 27. Addicoat, Matthew
    et al.
    Atkin, Rob
    Canongia Lopes, José Nuno
    Costa Gomes, Margarida
    Firestone, Millicent
    Gardas, Ramesh
    Halstead, Simon
    Hardacre, Christopher
    Hardwick, Laurence J.
    Holbrey, John
    Hunt, Patricia
    Ivaništšev, Vladislav
    Jacquemin, Johan
    Jones, Robert
    Kirchner, Barbara
    Lynden-Bell, Ruth
    MacFarlane, Doug
    Marlair, Guy
    Medhi, Himani
    Mezger, Markus
    Pádua, Agílio
    Pantenburg, Isabel
    Perkin, Susan
    Reid, Joshua E. S. J.
    Rutland, Mark W.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Saha, Satyen
    Shimizu, Karina
    Slattery, John M.
    Swadźba-Kwaśny, Malgorzata
    Tiwari, Shraeddha
    Tsuzuki, Seiji
    Uralcan, Betul
    van den Bruinhorst, Adriaan
    Watanabe, Masayoshi
    Wishart, James
    Structure and dynamics of ionic liquids: general discussion2018Inngår i: Faraday discussions, ISSN 1359-6640, E-ISSN 1364-5498, Vol. 206, nr 0, s. 291-337Artikkel i tidsskrift (Fagfellevurdert)
  • 28. Adekunle, Kayode
    et al.
    Cho, Sung-Woo
    Patzelt, Christian
    Blomfeldt, Thomas
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymera material.
    Skrifvars, Mikael
    Impact and flexural properties of flax fabrics and Lyocell fiber-reinforced bio-based thermoset2011Inngår i: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 30, nr 8, s. 685-697Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A bio-based thermoset resin was reinforced with flax fabrics and Lyocell fiber. The effect of different weave architectures was studied with four flax fabrics with different architectures: plain, twill (two different types), and dobby. The effect of the outer ply thickness was studied and characterized with flexural and impact testing. Composites manufactured with plain weave reinforcement had the best mechanical properties. The tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength were 280MPa, 32GPa, 250MPa, 25GPa, and 75 kJ/m (2), respectively. Reinforcements with twill-weave architecture did not impart appreciable flexural strength or flexural modulus even when the outer thickness was increased. Plain- and dobby (basket woven style)-weave architectures gave better reinforcing effects and the flexural properties increased with an increase in outer thickness. Water absorption properties of the composites were studied and it was observed that the hybridization with Lyocell fiber reduced the water uptake. Field-emission scanning electron microscopy was used to study the micro-structural properties of the composites.

  • 29.
    Adhikari, Arindam
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Claesson, Per M.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Pani, Jinshan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Deidinaitei, Andra
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Blomberg, Eva
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Electrochemical behavior and anticorrosion properties of modified polyaniline dispersed in polyvinylacetate coating on carbon steel2008Inngår i: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 53, nr 12, s. 4239-4247Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 30.
    Adhikari, Arindam
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Radhakrishnan, S.
    Patil, Rahul
    Influence of dopant ions on properties of conducting polypyrrole and its electrocatalytic activity towards methanol oxidation2009Inngår i: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 159, nr 15-16, s. 1682-1688Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The polypyrrole (PPy) films were deposited on vacuum metallized substrates by electro-oxidation of pyrrole monomer. These electrodes were then modified with a range of metal halides having different electronegativities. The modified polypyrrole electrodes were employed to investigate electrocatalytic activity towards methanol electrochemical oxidation by means of cyclic voltammetry in 0.1 M HClO4 as supporting electrolyte. It was found that the electronegativity of the dopant ion incorporated in the PPy film governs the electrocatalytic activity towards methanol oxidation. Among different dopant anions used in the present work, the PPy doped with zirconium chloride gave the highest anodic current of 10 mA cm(-2) at the oxidation potential of methanol. Electrical property and the charge created due to doping in the polymers were measured using X-ray photoelectron spectroscopy (XPS) and Electron spin resonance spectroscopy (ESR). Electrocatalytic activity of the modified electrodes was correlated with various factors obtained from different polymer characterization experiments. The results were explained on the basis of the charge-transfer efficiency at the electrode I electrolyte interface, which was associated with the acceptor state created by the dopant in the semi-conducting polymer.

  • 31. Adia, Madina Mohamed
    et al.
    Emami, Seyedeh Noushin
    Byamukama, Robert
    Faye, Ingrid
    Borg-Karlson, Anna-Karin
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Antiplasmodial activity and phytochemical analysis of extracts from selected Ugandan medicinal plants2016Inngår i: Journal of Ethnopharmacology, ISSN 0378-8741, E-ISSN 1872-7573, Vol. 186, s. 14-19Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ethnopharmacological relevance: Resistance of the parasites to known antimalarial drugs has provided the necessity to find new drugs from natural products against malaria. The aim of the study was to evaluate the in vitro antiplasmodial activity of some plants used by Traditional Medical Practitioners (TMPs) of Prometra and Rukararwe in malaria treatment in Uganda to provide scientific proof of the efficacies claimed by these Herbalists. Materials and methods: The air dried samples of Clerodendrum rotundifolium (leaves), Microglossa pyrifolia (leaves), Momordica foetida (leaves) and Zanthoxylum chalybeum (stem bark) used for malaria treatment by TMPs were successively extracted with ethyl acetate, methanol and water to yield twelve extracts. The extracts were tested against the chloroquine-sensitive (NF54) and chloroquine-resistant (FCR3) Plasmodium falciparum strains in vitro using the micro Mark III test which is based on assessing the inhibition of schizont maturation. A compound A was extracted and purified from the stem bark of Z. chalybeum and its structure was identified and confirmed by spectroscopic methods. Results: Most of the extracts tested (92%) showed an antiplasmodial activity with IC50 < 50 mu g/mL. In spite of successive extractions with different solvents, potent anti-plasmodial activity (IC50 < 5 mu g/mL) was observed in the ethyl acetate, methanol and aqueous extracts of M. pyrifolia and C. rotundifolium. Preferential enrichments of activity into water (IC50 < 15 mu g/mL) and Ethyl acetate (IC50 < 5 mu g/mL) were seen in the case of M. foetida and Z chalybeum respectively. The most active extracts were from C rotundifolium and M. pyrifolia with IC50 values less than 2 mu g/mL. Phytochemical analysis of the extracts revealed the presence of saponins, tannins, flavonoids, alkaloids and cardiac glycocides. Fagaramide isolated from Z chalybeum had a higher activity (IC50 2.85 mu g/mL) against the chloroquine-resistant strain than against the chloroquine-senstive (IC50 16.6 mu g/mL) strain used in the study. Conclusion: The plant extracts analysed in this study presented an average antiplasmodial activity (58%). This study revealed for the first time the antiplasmodial activity of the plant C. rotundofolium. It's the first time the compound fagaramide (N-isobutyl-3-(3,4-methylene dioxyphenyl) - 2E-propenamide) has been isolated from Z. chalybeum as one of the compounds that contribute to the activity of this plant against P. falciparum.

  • 32. Adler, Belinda
    et al.
    Boström, Tove
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Ekström, Simon
    Hober, Sophia
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Laurell, Thomas
    Miniaturized and Automated High-Throughput Verification of Proteins in the ISET Platform with MALDI MS2012Inngår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 84, nr 20, s. 8663-8669Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A major bottleneck in high-throughput protein production is the validation step, which is why parallel and automated sample processing methods are highly desirable. Also, a miniaturized sample preparation format is preferred, as the reduction of reagent volumes significantly decreases the analysis cost per sample. We have developed an automated and miniaturized protein sequence verification protocol for recombinant proteins utilizing peptide mass fingerprinting and MS/MS analysis. The integrated selective enrichment target (ISET) platform, previously developed in our group, with its dual functionality, being both a sample preparation platform and a MALDI target plate, is employed. All steps including immobilized metal ion affinity chromatography of protein on cobalt-loaded beads, tryptic digestion, and MALDI MS analysis are performed in an array format, without any sample transfers, on the same ISET chip. The automated configuration reduced the sample preparation time significantly. Starting with crude lysate, a full plate of 48 purified, digested samples prepared for MALDI-MS can be generated in 4 h, with only 30 min of operator involvement. This paper demonstrates the utility of the method by parallel analysis of 45 His-tagged human recombinant proteins.

  • 33.
    Adolfsson, Erik
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Future-competing battery chemistries for large-scale energy storage2023Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    ’Netto-noll utsläpp’ i EU vid 2050 är ett av målen för att påskynda övergången från fossila bränslen till mer förnyelsebara och hållbara alternativ. Detta har däremot introducerat mer turbulens på elnäten. Ett av verktygen för att reglera och förbättra eldistributionen är stor-skaliga batterier, där litium-jon är den mest förekommande kemin. Men på grund av oro kring resursutbud och hopp om teknologidiversifiering har det påbörjat en sökning efter alternativ som kan användas i stället eller tillsammans med litium-jon batterier. Från en lång lista så har tre alternativ med hög potential identifierats. Dessa är nickel-vätgasbatteri, zink-brom flödesbatteri och järn-luftbatteri. Deras lämplighet undersöktes och diskuterades för flertalet användningsområden och för ett speciellt användarfall av Vattenfall. Slutsatsen var att utav de tre, så är det endast nickel-vätgas som kan förväntas vara ett bra alternativ för specifika fall, att zink-brom har få möjligheter att konkurrera och att järn-luft har väldigt hög potential men också många oklarheter som gör det svårt att förutspå dess utveckling.

    Fulltekst (pdf)
    fulltext
  • 34.
    Adolfsson, Karin H.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Hassanzadeh, Salman
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Valorization of cellulose and waste paper to graphene oxide quantum dots2015Inngår i: RSC Advances, E-ISSN 2046-2069, Vol. 5, nr 34, s. 26550-26558Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biobased graphene oxide quantum dots (GOQD) were derived from cellulose via carbon nanospheres (CN) as intermediate products. Solid CN were synthesized from cellulose through microwave-assisted hydrothermal degradation of alpha-cellulose with H2SO4 as a catalyst at 160 degrees C. The obtained CN were further utilized for the synthesis of GOQD by a two-step reaction including 30 minutes of sonication followed by heating at 90 degrees C under O-rich acidic conditions (HNO3). This process broke down the 3D CN to 2D GOQD. The size of the synthesized GOQD was controlled by the heating time, reaching a dot diameter of 3.3 nm and 1.2 nm after 30 and 60 minutes of heating, respectively. The synthesis process and products were characterized by multiple analytical techniques including FTIR, TGA, SEM, TEM, XPS, XRD, BET, DLS and AFM. Interesting optical properties in aqueous solutions were demonstrated by UV/Vis and fluorescence spectroscopy. Finally we demonstrated that corresponding GOQD can be synthesized from waste paper. This production route thus uses renewable and cheap starting materials and relatively mild synthesis procedures leads to instant nanometric production of 2D dots. In addition it enables recycling of low quality waste to value-added products.

  • 35.
    Adolfsson, Karin H.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. Sch Chem Sci & Engn, Stockholm, Sweden..
    Hassanzadeh, Salman
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. Sch Chem Sci & Engn, Stockholm, Sweden..
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Value-added carbon products attained through microwave assisted hydrothermal treatment of cellulose and waste paper2016Inngår i: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 251Artikkel i tidsskrift (Annet vitenskapelig)
  • 36.
    Adolfsson, Karin H.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Huang, Ping
    Department of Chemistry – Ångström Laboratory, Uppsala University, Box 523, Uppsala, 751 20, Sweden, Box 523.
    Golda-Cepa, Monika
    Faculty of Chemistry, Jagiellonian Universityul, Krakow, 30–387, Poland.
    Xu, Huan
    School of Materials Science and Physics, China University of Mining and Technology, Xuzhou, 221116, P. R. China.
    Kotarba, Andrzej
    Faculty of Chemistry, Jagiellonian Universityul, Krakow, 30–387, Poland.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Scavenging of DPPH by Persistent Free Radicals in Carbonized Particles2023Inngår i: Advanced Sustainable Systems, E-ISSN 2366-7486, Vol. 7, nr 3, artikkel-id 2200425Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 37.
    Adolfsson, Karin H.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Xie, L.
    Hassanzadeh, Salman
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Pettersson, Torbjörn
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Zero-Dimensional and Highly Oxygenated Graphene Oxide for Multifunctional Poly(lactic acid) Bionanocomposites2016Inngår i: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 4, nr 10, s. 5618-5631Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The unique strengths of 2D graphene oxide nanosheets (GONSs) in polymer composites are thwarted by nanosheet agglomeration due to strong intersheet attractions. Here, we reveal that shrinking the planar size to 0D graphene oxide quantum dots (GOQDs), together with the intercalation of rich oxygen functional groups, reduces filler aggregation and enhances interfacial interactions with the host polymer. With poly(lactic acid) (PLA) as a model matrix, atomic force microscopy colloidal probe measurements illustrated that a triple increase in adhesion force to PLA was achieved for GOQDs (234.8 nN) compared to GONSs (80.4 nN), accounting for the excellent exfoliation and dispersion of GOQDs in PLA, in contrast to the notable agglomeration of GONSs. Although present at trace amount (0.05 wt %), GOQDs made a significant contribution to nucleation activity, mechanical strength and ductility, and gas barrier properties of PLA, which contrasted the inferior efficacy of GONSs, accompanied by clear distinction in film transparency (91% and 50%, respectively). Moreover, the GOQDs with higher hydrophilicity accelerated the degradation of PLA by enhancing water erosion, while the GONSs with large sheet surfaces gave a higher hydrolytic resistance. Our findings provide conceptual insights into the importance of the dimensionality and surface chemistry of GO nanostructures in the promising field of bionanocomposites integrating high strength and multifunction (e.g., enhanced transparency, degradation and gas barrier).

  • 38.
    Adolfsson, Karin
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Yadav, Nisha
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Cellulose-derived hydrothermally carbonized materials and their emerging applications2020Inngår i: Current Opinion in Green and Sustainable Chemistry, E-ISSN 2452-2236 , Vol. 23, s. 18-24Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hydrothermally carbonized cellulose and its further modifications are intriguing materials for a wide range of potential applications. Hydrothermal carbonization is a sustainable process for converting biopolymers or other biomass sources into carbonaceous materials under mild conditions in water and at relatively low temperatures. This review presents the latest progress in modification and utilization of hydrothermally carbonized cellulose and related materials in environmental, biomedical, and energy applications. Further applications presented include evaluation of cellulose-derived carbon spheres or carbon dots as catalysts, antibacterial materials, flame retardants, and functional fillers in bioplastic composites. The wide range of applications highlights the great potential and multifunctionality of hydrothermally carbonized cellulose and its derivatives. The field is expected to further expand and increase in importance as we move toward circular bioeconomy.

  • 39.
    Adorno Lopes, Denise
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnenergiteknik.
    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, Skolan för teknikvetenskap (SCI), Fysik, Kärnenergiteknik.
    Experimental and computational assessment of U-Si-N ternary phases2019Inngår i: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 516, s. 194-201Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 40.
    Afewerki, Samson
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Edlund, Ulrica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Combined Catalysis: A Powerful Strategy for Engineering Multifunctional Sustainable Lignin-Based Materials2023Inngår i: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 17, nr 8, s. 7093-7108Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The production and engineering of sustainable materials through green chemistry will have a major role in our mission of transitioning to a more sustainable society. Here, combined catalysis, which is the integration of two or more catalytic cycles or activation modes, provides innovative chemical reactions and material properties efficiently, whereas the single catalytic cycle or activation mode alone fails in promoting a successful reaction. Polyphenolic lignin with its distinctive structural functions acts as an important template to create materials with versatile properties, such as being tough, antimicrobial, self-healing, adhesive, and environmentally adaptable. Sustainable lignin-based materials are generated by merging the catalytic cycle of the quinone-catechol redox reaction with free radical polymerization or oxidative decarboxylation reaction, which explores a wide range of metallic nanoparticles and metal ions as the catalysts. In this review, we present the recent work on engineering lignin-based multifunctional materials devised through combined catalysis. Despite the fruitful employment of this concept to material design and the fact that engineering has provided multifaceted materials able to solve a broad spectrum of challenges, we envision further exploration and expansion of this important concept in material science beyond the catalytic processes mentioned above. This could be accomplished by taking inspiration from organic synthesis where this concept has been successfully developed and implemented.

  • 41.
    Afewerki, Samson
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Edlund, Ulrica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Engineering an All-Biobased Solvent- and Styrene-Free Curable Resin2023Inngår i: ACS Polymers Au, E-ISSN 2694-2453, Vol. 3, nr 6, s. 447-456Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The sustainable production of polymers and materials derived from renewable feedstocks such as biomass is vital to addressing the current climate and environmental challenges. In particular, finding a replacement for current widely used curable resins containing undesired components with both health and environmental issues, such as bisphenol-A and styrene, is of great interest and vital for a sustainable society. In this work, we disclose the preparation and fabrication of an all-biobased curable resin. The devised resin consists of a polyester component based on fumaric acid, itaconic acid, 2,5-furandicarboxylic acid, 1,4-butanediol, and reactive diluents acting as both solvents and viscosity enhancers. Importantly, the complete process was performed solvent-free, thus promoting its industrial applications. The cured biobased resin demonstrates very good thermal properties (stable up to 415 °C), the ability to resist deformation based on the high Young’s modulus of ∼775 MPa, and chemical resistance based on the swelling index and gel content. We envision the disclosed biobased resin having tailorable properties suitable for industrial applications.

  • 42. Afonso, Damien
    et al.
    Valetti, Sabrina
    Fraix, Aurore
    Bascetta, Claudia
    Petralia, Salvatore
    Conoci, Sabrina
    Feiler, Adam
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Sortino, Salvatore
    Multivalent mesoporous silica nanoparticles photo-delivering nitric oxide with carbon dots as fluorescence reporters2017Inngår i: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 9, nr 36, s. 13404-13408Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Amino-terminated mesoporous silica nanoparticles embedding carbon dots (MSCD) formed by calcination were functionalized with a nitric oxide (NO) photodonor (1) to give a robust MSCD-1 conjugate. The intense fluorescence of MSCDs was strongly quenched in MSCD-1 by effective energy transfer. Visible light excitation of MSCD-1 liberates NO, suppresses the energy transfer mechanism and leads to concomitant fluorescence restoration of the MSCD scaffold, which acts as an optical reporter for the released NO. The MSCD-1 hybrid is also able to encapsulate the highly hydrophobic photosensitizer temoporfin, preserving the fluorescence reporting function.

  • 43.
    Afrasiabi, Roodabeh
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Jokilaakso, Nima
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Schmidt, Torsten
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Björk, P.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Linnros, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Effect of microwave-assisted silanization on sensing properties of silicon nanoribbon FETs2015Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 209, s. 586-595Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 44. Afshar, Majid Ghahraman
    et al.
    Crespo, Gaston A.
    Bakker, Eric
    Coulometric Calcium Pump for Thin Layer Sample Titrations2015Inngår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 87, nr 19, s. 10125-10130Artikkel i tidsskrift (Fagfellevurdert)
  • 45. Afshar, Majid Ghahraman
    et al.
    Crespo, Gaston A.
    Bakker, Eric
    Counter electrode based on an ion-exchanger Donnan exclusion membrane for bioelectroanalysis2014Inngår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 61, s. 64-69Artikkel i tidsskrift (Fagfellevurdert)
  • 46. Afshar, Majid Ghahraman
    et al.
    Crespo, Gaston A.
    Bakker, Eric
    Direct Ion Speciation Analysis with Ion-Selective Membranes Operated in a Sequential Potentiometric/Time Resolved Chronopotentiometric Sensing Mode2012Inngår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 84, nr 20, s. 8813-8821Artikkel i tidsskrift (Fagfellevurdert)
  • 47. Afshar, Majid Ghahraman
    et al.
    Crespo, Gaston A.
    Bakker, Eric
    Flow Chronopotentiometry with Ion-Selective Membranes for Cation, Anion, and Polyion Detection2016Inngår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 88, nr 7, s. 3945-3952Artikkel i tidsskrift (Fagfellevurdert)
  • 48. Afshar, Majid Ghahraman
    et al.
    Crespo, Gaston A.
    Bakker, Eric
    Thin-Layer Chemical Modulations by a Combined Selective Proton Pump and pH Probe for Direct Alkalinity Detection2015Inngår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 54, nr 28, s. 8110-8113Artikkel i tidsskrift (Fagfellevurdert)
  • 49. Afshar, Majid Ghahraman
    et al.
    Crespo, Gaston A.
    Dorokhin, Denis
    Neel, Bastien
    Bakker, Eric
    Thin Layer Coulometry of Nitrite with Ion-Selective Membranes2015Inngår i: Electroanalysis, ISSN 1040-0397, E-ISSN 1521-4109, Vol. 27, nr 3, s. 609-615Artikkel i tidsskrift (Fagfellevurdert)
  • 50. Afshar, Majid Ghahraman
    et al.
    Crespo, Gaston A.
    Xie, Xiaojiang
    Bakker, Eric
    Direct Alkalinity Detection with Ion-Selective Chronopotentiometry2014Inngår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 86, nr 13, s. 6461-6470Artikkel i tidsskrift (Fagfellevurdert)
1234567 1 - 50 of 9329
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