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1.	Lundberg, Daniel, et al. (författare) The Chemical Side of SLU : Book of Abstracts 2011 Annan publikation (övrigt vetenskapligt/konstnärligt)
2.	Swerin, Agne, et al. (författare) Formulation of superhydrophobic pigment coatings 2015 Ingår i: Formulation of superhydrophobic pigment coatings. - : TAPPI Press. - 9781510818873 ; , s. 1410-1424 Konferensbidrag (refereegranskat)
3.	Maurina Morais, Eduardo, 1989, et al. (författare) Solvent-free synthesis of protic ionic liquids. Synthesis, characterization and computational studies of triazolium based ionic liquids 2022 Ingår i: Journal of Molecular Liquids. - : Elsevier BV. - 0167-7322. ; 360 Tidskriftsartikel (refereegranskat)abstract A series of triazolium and imidazolium based protic ionic liquids were synthesized using a solvent-free method designed to address several limitations encountered with other commonly used methods. Using this method, pure (98–99% m/m) and dry (128–553 ppm of water) protic ionic liquids were synthesized (in a laboratory scale) without the need for purification methods that require heating the ionic liquid, hence avoiding the common issue of thermal decomposition. This method was also designed to allow for the accurate measurement of acid and base, and for the controlled mixing of both compounds, which is essential to avoid producing impure protic ionic liquids with excess of either acid or base. The system is constructed of only glass and chemically resistant polymer (PTFE and PVDF) parts, which avoid other contaminants that can result from unwanted reactions involving the reagents with common laboratory tools (metallic objects, paper, plastic, etc.). This process is described in detail in the paper as well as in a video. The resulting ionic liquids were carefully analyzed by spectroscopic and thermal methods designed to avoid water absorption, which is known to affect their properties. To complement this experimental characterization, computational chemistry tools were used to assess the ionic liquids’ properties, as well as to assign vibrational modes.
4.	Maurina Morais, Eduardo, 1989 (författare) Synthesis of protic ionic liquids. Challenges and solutions for the synthesis of pure compounds. 2022 Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract The urgent need to diversify our energy matrix is responsible for a renewed interest in fuel cell technology, which can use hydrogen gas, a renewable green fuel, as an energy source. This technology is currently a commercially available option, however, it still requires technological improvements before it can be widely used for different applications. One way this technology could potentially be improved is by increasing its temperature range of operation by developing new, anhydrous proton conducting materials. Protic ionic liquids, which are organic salts with low melting temperatures, are interesting candidates for this application, since they can conduct protons in the operational conditions of fuel cells and without the need of water. These compounds can be synthesized by a simple acid-base neutralization reaction, but certain considerations must be taken in order to obtain high quality (dry and pure) protic ionic liquids. In this thesis, a series of triazolium and imidazolium based protic ionic liquids were synthesized using a solvent-free method designed to address several limitations encountered with other commonly used methods. Using this method, pure (98-99% m/m) and dry (128-553 ppm of water) protic ionic liquids were synthesized (in a laboratory scale) without the need for purification methods that require heating the ionic liquid, hence avoiding the common issue of thermal decomposition. This method was also designed to allow for the accurate measurement of acid and base, and for the controlled mixing of both compounds, which is essential to avoid producing impure protic ionic liquids with excess of either acid or base. The system is consists of only glass and chemically resistant polymer(PTFE and PVDF) parts, which avoids other contaminants that can result from unwanted reactions involving the reagents with common laboratory tools (metallic objects, paper, plastic, etc.). The resulting ionic liquids were carefully analyzed by spectroscopic and thermal analysis methods designed to avoid water absorption, which is known to affect their properties. To complement this experimental characterization, computational chemistry tools were used to assess the ionic liquids’ properties, as well as to assign vibrational modes.
5.	Nyström-Larsson, Ingalill, 1969, et al. (författare) Materialanalys av sydsvenskt bonadsmåleri 2007 Ingår i: Rapport: Sammanfattning av Riksantikvarieämbetets seminarieserie 2007 kring pågående FoU-projekt. ; , s. 23-24 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Bonadsmåleriet hade sin storhetstid 1750-1850, och var influerat av medeltida kalkmåleri och bildvävnad i kyrkorna. Bonaderna var temporära och prydde stugorna till fest. Motiven kan vara både bibliska och profana. Materialet är tyger (återanvända och hopfogade) och senare även papper. Mot slutet av perioden övergår hantverket i massproduktion. Tidigare har bonaderna framför allt studerats inom humaniora (exempelvis etnologi) och ett naturvetenskapligt perspektiv har saknats. Därför finns mycket knapphändiga uppgifter om materialet. Syftet med projektet är att: • Kartlägga materialanvändningen • Tolka och förstå materialutvecklingen • Klarlägga innehållet i de otydliga trivialnamnen • Bygga upp ett referensmaterial Genomförande Ett antal frågeställningar har satts upp inför studiet: • Vilka materialval har man gjort? • Skiljer måleriteknik, färg, materialval mellan bonader, och går det att urskilja geografiska skillnader eller är det en tidsmässig utveckling? • Kan bonader attribueras utifrån materialval och färgval? • Vad är det för pigment som döljs i trivialnamnen? Skriftliga källor räcker inte för att svara på dessa frågor utan måste komplet-teras med naturvetenskapliga analyser. Diskussion kring RÄA-seminariets specifika frågeställningar På vad sätt bidrar ert projekt till kunskapsuppbyggnaden inom ert område? • Projektet är också ett pilotprojekt och den kunskap som vinns kan också appliceras på annat än bonadsmåleri. Utifrån resultaten kan man också gå vidare och titta på handelsvägar, infrastruktur etc. • En referensdatabas byggs upp och kan kanske också användas för an-nat material. På vilket sätt skulle resultaten från ert projekt kunna tillämpas mer konkret inom kulturmiljösektorn? • Ett viktigt mål är att hitta analysmetoder som inte förstör materialet, och som helst kan göras på plats så att materialet inte behöver flyttas (Raman spektroskopi). • Som konstaterades ovan kan resultaten från den kemiska analysen visa att en sådan kan komplettera traditionella historiska metoder också inom andra områden än bonadsmåleri. Frågor och öppen diskussion • Ännu har man inte hittat några speciella pigment eller färger, men analysen är inte klar. • Analysmaterialet som valts ut är signerade bonader. • Eftersom uppbyggandet av referensdatabaser är centralt i konserva-torns arbete är det viktigt att sprida resultaten av projektet.
6.	Kong, Xiangrui, et al. (författare) Molecular Characterization of Emissions from a Residential Wood Burning Boiler 2021 Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 754 Tidskriftsartikel (refereegranskat)
7.	Damas, Giane Benvinda, et al. (författare) Carbon dioxide reduction mechanism on Ru-based electrocatalysts [Ru(bpy)(2)(CO)(2)](2+) : insights from first-principles theory 2021 Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry. - 2398-4902. ; 5:23, s. 6066-6076 Tidskriftsartikel (refereegranskat)abstract Solar fuel production through the so-called artificial photosynthesis has attracted a great deal of attention to the development of a new world energy matrix that is renewable and environmentally friendly. This process is characterized by light absorption with enough photon energy to generate conduction electrons, which drive the carbon dioxide reduction to produce organic fuels. It is also common to couple Ru-complex electrocatalysts to form a more efficient and selective hybrid system for this application. In this work, we have undertaken a thorough investigation of the redox reaction mechanism of Ru-based electrocatalysts by means of density functional theory (DFT) methods under the experimental conditions that have been previously reported. More specifically, we have studied the electrochemistry and catalytic activity of the [Ru(bpy)(2)(CO)(2)](2+) coordination complex. Our theoretical assessment supports the following catalytic cycle: (i) [Ru(bpy)(2)(CO)(2)](2+) is transformed into [Ru(bpy)(2)(CO)](0) upon two-electron reduction and CO release; (ii) [Ru(bpy)(2)(CO)](0) is protonated to form the [Ru(bpy)(2)(CO)H](+) hydride complex; (iii) CO2 is activated by the hydride complex through an electrophilic addition to form the [Ru(bpy)(2)(CO)(OCHO)](+) intermediate; (iv) the resulting formic acid ligand is released in solution; and, finally, (v) the CO ligand is reattached to the complex to recover the initial [Ru(bpy)(2)(CO)(2)](2+) catalyst.
8.	van den Bossche, Maxime, 1989 (författare) Methane oxidation over palladium oxide. From electronic structure to catalytic conversion 2017 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract Understanding how catalysts work down to the atomic level can provide ways to improve chemical processes on which our contemporary economy is heavily reliant. The oxidation of methane is one such example, which is important from an environmental point of view. Methane is a potent greenhouse gas and natural and biogas vehicles need efficient catalysts to prevent slip of uncombusted fuel into the exhaust. Commercial catalysts for methane oxidation are often based on palladium or platinum. Metallic palladium, however, is easily converted to palladium oxide when the engine is operated at oxygen rich conditions. In this thesis, various aspects of complete methane oxidation over PdO(101) are investigated with computational methods based on density functional theory (DFT). PdO(101) is the active surface for methane oxidation, and firstly, the reaction intermediates CO and H are studied in detail. Possible pathways for H2 adsorption, dissociation and eventual water formation are investigated, in connection to core-level spectroscopy experiments. Similarly, the adsorption configurations for carbon monoxide on clean and oxidized palladium are examined with a combination of DFT calculations, core-level and infrared spectroscopy. Secondly, a detailed kinetic model is constructed that describes the catalytic conversion of CH4 to CO2 and H2O over PdO(101). This is done in a first-principles microkinetics framework, where the kinetic parameters are obtained by applying density functional and transition state theory. The kinetic model provides a fundamental understanding of findings from reactor experiments, such as the rate limiting steps and poisoning behaviour, and shows qualitatively different behaviour of adsorbates on oxide as compared to metal surfaces. Lastly, limitations of the commonly used class of generalized gradient functionals are illustrated in the computation of several properties of adsorbates on metal oxide surfaces. These include core-level shifts and thermodynamic and reactive properties of adsorbates on the PdO(101) surface. Similarly, the description of several molecular and cooperative adsorption processes are also found to be sensitive to the applied exchange-correlation functional on the BaO(100), TiO2(110) and CeO2(111) surfaces.
9.	Bannan, T. J., et al. (författare) A method for extracting calibrated volatility information from the FIGAERO-HR-ToF-CIMS and its experimental application 2019 Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 12:3, s. 1429-1439 Tidskriftsartikel (refereegranskat)abstract The Filter Inlet for Gases and AEROsols (FIGAERO) is an inlet specifically designed to be coupled with the Aerodyne High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (HR-ToF-CIMS). The FIGAERO-HR-ToF-CIMS provides simultaneous molecular information relating to both the gas- and particle-phase samples and has been used to extract vapour pressures (VPs) of the compounds desorbing from the filter whilst giving quantitative concentrations in the particle phase. However, such extraction of vapour pressures of the measured particle-phase components requires use of appropriate, well-defined, reference compounds. Vapour pressures for the homologous series of polyethylene glycols (PEG) ((H-(O-CH 2 CH 2 ) n -OH) for n = 3 to n = 8), covering a range of vapour pressures (VP) (10 -1 to 10 -7 Pa) that are atmospherically relevant, have been shown to be reproduced well by a range of different techniques, including Knudsen Effusion Mass Spectrometry (KEMS). This is the first homologous series of compounds for which a number of vapour pressure measurement techniques have been found to be in agreement, indicating the utility as a calibration standard, providing an ideal set of benchmark compounds for accurate characterization of the FIGAERO for extracting vapour pressure of measured compounds in chambers and the real atmosphere. To demonstrate this, single-component and mixture vapour pressure measurements are made using two FIGAERO-HR-ToF-CIMS instruments based on a new calibration determined from the PEG series. VP values extracted from both instruments agree well with those measured by KEMS and reported values from literature, validating this approach for extracting VP data from the FIGAERO. This method is then applied to chamber measurements, and the vapour pressures of known products are estimated. © 2019 Author(s).
10.	Franz, Jan, 1973 (författare) Some new theoretical tools for the study of electronically excited states of molecules 2010 Ingår i: Technical University Chemnitz. Konferensbidrag (övrigt vetenskapligt/konstnärligt)
11.	Guo, Y. D., et al. (författare) Identification of highly oxygenated organic molecules and their role in aerosol formation in the reaction of limonene with nitrate radical 2022 Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 22:17, s. 11323-11346 Tidskriftsartikel (refereegranskat)abstract Nighttime NO3-initiated oxidation of biogenic volatile organic compounds (BVOCs) such as monoterpenes is important for the atmospheric formation and growth of secondary organic aerosol (SOA), which has significant impact on climate, air quality, and human health. In such SOA formation and growth, highly oxygenated organic molecules (HOM) may be crucial, but their formation pathways and role in aerosol formation have yet to be clarified. Among monoterpenes, limonene is of particular interest for its high emission globally and high SOA yield. In this work, HOM formation in the reaction of limonene with nitrate radical (NO3) was investigated in the SAPHIR chamber (Simulation of Atmospheric PHotochemistry In a large Reaction chamber). About 280 HOM products were identified, grouped into 19 monomer families, 11 dimer families, and 3 trimer families. Both closed-shell products and open-shell peroxy radicals (RO2 center dot) 2 were observed, and many of them have not been reported previously. Monomers and dimers accounted for 47% and 47% of HOM concentrations, respectively, with trimers making up the remaining 6 %. In the most abundant monomer families, C10H15-17NO6-14, carbonyl products outnumbered hydroxyl products, indicating the importance of RO2 center dot termination by unimolecular dissociation. Both RO2 center dot autoxidation and alkoxy-peroxy pathways were found to be important processes leading to HOM. Time-dependent concentration profiles of monomer products containing nitrogen showed mainly second-generation formation patterns. Dimers were likely formed via the accretion reaction of two monomer RO2 center dot , and HOM-trimers via the accretion reaction between monomer RO2 center dot and dimer RO2 center dot. Trimers are suggested to play an important role in new particle formation (NPF) observed in our experiment. A HOM yield of 1.5%(+1.7%)(-0.7%) was estimated considering only first-generation products. SOA mass growth could be reasonably explained by HOM condensation on particles assuming irreversible uptake of ultra-low volatility organic compounds (ULVOCs), extremely low volatility organic compounds (ELVOCs), and low volatility organic compounds (LVOCs). This work provides evidence for the important role of HOM formed via the limonene +NO3 reaction in NPF and growth of SOA particles.
12.	Le Breton, Michael, 1986, et al. (författare) Application of a FIGAERO ToF CIMS for on-line characterization of real-world fresh and aged particle emissions from buses 2019 Ingår i: Aerosol Science and Technology. - : Informa UK Limited. - 0278-6826 .- 1521-7388. ; 53:3, s. 244-259 Tidskriftsartikel (refereegranskat)abstract © 2019, © 2019 The Author(s). Published with license by Taylor & Francis Group, LLC. On-line chemical characterization of real-world particle emissions from 13 transit buses was performed using a chemical ionization mass spectrometer (CIMS) equipped with a filter inlet for gases and aerosols (FIGAERO). In addition to the fresh emissions the emissions were artificially aged using a potential aerosol mass reactor (Go:PAM). The buses studied were running on different fuel types (diesel, compressed natural gas, and rapeseed methyl ester) and exhaust after-treatment systems (selective catalytic reduction (SCR), exhaust gas recirculation (EGR), and a three-way catalyst). When evaluating emissions from passing exhaust plumes using the FIGAERO ToF-CIMS, two technical features were highlighted from this work, the use of high mass calibrants and the factor enhancement method to be able to filter important compounds from mass spectra including hundreds of species. Here, acetate was used as the reagent ion to enable detection of highly oxygenated species in the exhaust particle emissions with potential high toxicity and/or secondary organic aerosol formation (SOA) potential. The acetate ionization scheme accounted for 4% to 46% of the total emitted particulate mass through identification of 61 species in the spectra. For aged emission the various fuel types provided overlapping species that could explain up to 19% of the aged emissions. This is hypothesized to come from the oxidation of engine lubrication oil, thus a common source for various fuels which was further supported by laboratory measurements. Specific markers from the SCR technology, such as urea oxidation products and further byproducts from hydrolysis were identified and attributed to reactions of isocyanic acid.
13.	Le Breton, Michael, 1986, et al. (författare) Chlorine oxidation of VOCs at a semi-rural site in Beijing: significant chlorine liberation from ClNO2 and subsequent gas- and particle-phase Cl-VOC production 2018 Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 18:17, s. 13013-13030:18, s. 13013-13030 Tidskriftsartikel (refereegranskat)abstract Nitryl chloride (ClNO2) accumulation at night acts as a significant reservoir for active chlorine and impacts the following day's photochemistry when the chlorine atom is liberated at sunrise. Here, we report simultaneous measurements of N2O5 and a suite of inorganic halogens including ClNO2 and reactions of chloride with volatile organic compounds (Cl-VOCs) in the gas and particle phases utilising the Filter Inlet for Gas and AEROsols time-of-flight chemical ionisation mass spectrometer (FIGAERO-ToF-CIMS) during an intensive measurement campaign 40 km northwest of Beijing in May and June 2016. A maximum mixing ratio of 2900 ppt of ClNO2 was observed with a mean campaign nighttime mixing ratio of 487 ppt, appearing to have an anthropogenic source supported by correlation with SO2, CO and benzene, which often persisted at high levels after sunrise until midday. This was attributed to such high mixing ratios persisting after numerous e-folding times of the photolytic lifetime enabling the chlorine atom production to reach 2.3 x 10(5) molecules cm(-3) from ClNO2 alone, peaking at 09:30 LT and up to 8.4 x 10(5) molecules cm(-3) when including the supporting inorganic halogen measurements. Cl-VOCs were observed in the particle and gas phases for the first time at high time resolution and illustrate how the iodide ToF-CIMS can detect unique markers of chlorine atom chemistry in ambient air from both biogenic and anthropogenic sources. Their presence and abundance can be explained via time series of their measured and steady-state calculated precursors, enabling the assessment of competing OH and chlorine atom oxidation via measurements of products from both of these mechanisms and their relative contribution to secondary organic aerosol (SOA) formation.
14.	Li, J. J., et al. (författare) Characterization of Aerosol Aging Potentials at Suburban Sites in Northern and Southern China Utilizing a Potential Aerosol Mass (Go:PAM) Reactor and an Aerosol Mass Spectrometer 2019 Ingår i: Journal of Geophysical Research-Atmospheres. - : American Geophysical Union (AGU). - 2169-897X .- 2169-8996. ; 124:10, s. 5629-5649 Tidskriftsartikel (refereegranskat)abstract Aerosol mass spectrometry was used to characterize submicron aerosols before and after aging in a Gothenburg Potential Aerosol Mass (Go:PAM) reactor at two suburban sites in China, one in northern China at Changping (CP), Beijing, and a second in southern China at Hong Kong (HK). Organic aerosol (OA) dominated in the ambient nonrefractory particulate matter <1m (NR-PM1) for both CP (42-71%) and HK (43-61%), with a large contribution from secondary OA factors that were semivolatile oxygenated (SVOOA) and low-volatility oxygenated (LVOOA). Under constant OH exposure, OA enhancement (78-98%) dominated the NR-PM1 mass increment at both sites, while nitrate was enhanced the most among the inorganic species (7-9%). Overall, the CP site exhibited higher OA oxidation potential and more enhancement of SVOOA than LVOOA (7.5 vs. 2.7g/m(3)), but the reverse was observed in HK (0.8 vs. 2.6g/m(3)). In CP, more enhancement of the less oxygenated SVOOA suggests that aerosol aging was more sensitive to the abundant locally emitted primary OA and volatile organic compound precursors. On the contrary, the more formation of the highly oxidized LVOOA in HK indicates that aerosol aging mainly escalated the degree of oxygenation of OA as ambient aerosol was already quite aged and there was a lack of volatile organic compound precursors. The comparative measurements using the same oxidation system reveal distinct key factors and mechanisms that influence secondary aerosol formation in two suburban locations in China, providing scientific insights to assist formulation of location-specific mitigation measures of secondary pollution. Plain Language Summary Atmospheric submicron particles have significant impacts on the climate and human health. A large part of these particles are formed secondarily through successive aging of primary emissions. To study such aging processes, we used a reactor that can provide highly oxidizing conditions to simulate the oxidation of ambient aerosols at accelerated rates. An online mass spectrometer was connected after the reactor to measure changes in aerosol mass concentration and chemical composition between the ambient samples and the oxidized ones. We presented the first comparative measurements of the aging potentials of ambient aerosols in two suburban sites in northern and southern China (Changping District in Beijing, and Hong Kong). Results showed that generally aerosols at the Changping site had higher aging potentials after passing through the oxidation reactor, probably due to more local emissions of precursors, while air masses in Hong Kong were already in a higher oxidation state with lower aging potentials, mainly because of strong impacts from long-range transported pollution sources. Distinct aerosol aging pathways related to different ambient precursors were observed at the two sites. Understanding of the different characteristics of aerosol aging processes can lead to advances in air quality modeling and pollution management.
15.	Mohr, Claudia, et al. (författare) Molecular identification of organic vapors driving atmospheric nanoparticle growth 2019 Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10 Tidskriftsartikel (refereegranskat)abstract Particles formed in the atmosphere via nucleation provide about half the number of atmospheric cloud condensation nuclei, but in many locations, this process is limited by the growth of the newly formed particles. That growth is often via condensation of organic vapors. Identification of these vapors and their sources is thus fundamental for simulating changes to aerosol-cloud interactions, which are one of the most uncertain aspects of anthropogenic climate forcing. Here we present direct molecular-level observations of a distribution of organic vapors in a forested environment that can explain simultaneously observed atmospheric nanoparticle growth from 3 to 50nm. Furthermore, the volatility distribution of these vapors is sufficient to explain nanoparticle growth without invoking particle-phase processes. The agreement between observed mass growth, and the growth predicted from the observed mass of condensing vapors in a forested environment thus represents an important step forward in the characterization of atmospheric particle growth.
16.	Artemenko, A., et al. (författare) Reference XPS spectra of amino acids 2021 Konferensbidrag (refereegranskat)abstract In this report we present XPS data for five amino acids (AAs) (tryptophan, methionine, glutamine, glutamic acid, and arginine) with different side chain groups measured in solid state (powder form). The theoretically and experimentally obtained chemical structure of AAs are compared. Here, we analyse and discuss C 1 s, N 1 s, O 1s and S 2p core level binding energies, FWHMs, atomic concentrations of the functional groups in AAs. The experimentally obtained and theoretically calculated ratio of atomic concentrations are compared. The zwitterionic nature of methionine and glutamine in solid state was determined from protonated amino groups in N 1s peak and deprotonated carboxylic groups in the C 1s spectrum. The obtained XPS results for AAs well correspond with previously reported data.
17.	Barišić, Antun, et al. (författare) Experimental Data Contributing to the Elusive Surface Charge of Inert Materials in Contact with Aqueous Media 2021 Ingår i: Colloids and interfaces. - : MDPI. - 2504-5377. ; 5:1 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract We studied the charging of inert surfaces (polytetrafluoroethylene, i.e., PTFE; graphite; graphene; and hydrophobic silica) using classical colloid chemistry approaches. Potentiometric titrations showed that these surfaces acquired less charge from proton-related reactions than oxide minerals. The data from batch-type titrations for PTFE powder did not show an effect of ionic strength, which was also in contrast with results for classical colloids. In agreement with classical colloids, the electrokinetic results for inert surfaces showed the typical salt level dependence. In some cases, the point of zero net proton charge as determined from mass and tentatively from acid–base titration differed from isoelectric points, which has also been previously observed, for example by Chibowski and co-workers for ice electrolyte interfaces. Finally, we found no evidence for surface contaminations of our PTFE particles before and after immersion in aqueous solutions. Only in the presence of NaCl-containing solutions did cryo-XPS detect oxygen from water. We believe that our low isoelectric points for PTFE were not due to impurities. Moreover, the measured buffering at pH 3 could not be explained by sub-micromolar concentrations of contaminants. The most comprehensive explanation for the various sets of data is that hydroxide ion accumulation occurred at the interfaces between inert surfaces and aqueous solutions.
18.	Brinck, Tore, et al. (författare) Green Energetic Materials, Chapter 2: "Theoretical Design of Green Energetic Materials: Predicting Stability, Detection, Synthesis and Performance" 2014 Ingår i: Green Energetic Materials. - 9781119941293 ; , s. 15-44 Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract Since the end of the 20th century it has been increasingly realised that the use, or production, of many energetic materials leads to the release of substances which are harmful to both humans and the environment. To address this, the principles of green chemistry can be applied to the design of new products and their manufacturing processes, to create green energetic materials that are virtually free of environmental hazards and toxicity issues during manufacturing, storage, use and disposal. Active research is underway to develop new ingredients and formulations, green synthetic methods and non-polluting manufacturing processes.Green Energetic Materials provides a detailed account of the most recent research and developments in the field, including green pyrotechnics, explosives and propellants. From theoretical modelling and design of new materials, to the development of sustainable manufacturing processes, this book addresses materials already on the production line, as well as considering future developments in this evolving field.Topics covered include:Theoretical design of green energetic materialsDevelopment of green pyrotechnicsGreen primary and secondary explosivesOxidisers and binder materials for green propellantsEnvironmentally sustainable manufacturing technologies for energetic materialsElectrochemical methods for synthesis of energetic materials and waste remediationGreen Energetic Materials is a valuable resource for academic, industrial and governmental researchers working on the development of energetic materials, for both military and civilian applications.
19.	Brinck, T, et al. (författare) Green Energetic Materials, Chapter 7: "Green propellants Based on Dinitramide Salts: Mastering Stability and Chemical Compatibility Issues" 2014 Ingår i: Green Energetic Materials, kapitel 7. - 9781119941293 ; , s. 179-204 Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract Since the end of the 20th century it has been increasingly realised that the use, or production, of many energetic materials leads to the release of substances which are harmful to both humans and the environment. To address this, the principles of green chemistry can be applied to the design of new products and their manufacturing processes, to create green energetic materials that are virtually free of environmental hazards and toxicity issues during manufacturing, storage, use and disposal. Active research is underway to develop new ingredients and formulations, green synthetic methods and non-polluting manufacturing processes.Green Energetic Materials provides a detailed account of the most recent research and developments in the field, including green pyrotechnics, explosives and propellants. From theoretical modelling and design of new materials, to the development of sustainable manufacturing processes, this book addresses materials already on the production line, as well as considering future developments in this evolving field.Topics covered include:Theoretical design of green energetic materialsDevelopment of green pyrotechnicsGreen primary and secondary explosivesOxidisers and binder materials for green propellantsEnvironmentally sustainable manufacturing technologies for energetic materialsElectrochemical methods for synthesis of energetic materials and waste remediationGreen Energetic Materials is a valuable resource for academic, industrial and governmental researchers working on the development of energetic materials, for both military and civilian applications.
20.	Ubhayasekera, Sarojini J. K. A., et al. (författare) Assessment of Sterol Oxidation in Oils Recovered from Exhausted Bleaching Earth by Coupled Capillary Column GC and GC–MS Methods 2012 Ingår i: Journal of the American Oil Chemists Society. - : Wiley. - 0003-021X .- 1558-9331. ; 89:8, s. 1427-1433 Tidskriftsartikel (refereegranskat)abstract Cholesterol and phytosterols are generally present in foods at ppm levels and they can generate many oxidation products, i.e. oxysterols. The oxysterols comprise only a small percentage of unoxidized sterols. Reliable quantitative data on these compounds requires reasonably good separation by capillary column GC. The present study attempts to overcome the difficulties involved in separating many common oxysterols generated from cholesterol, brassicasterol, campesterol, stigmasterol, and sitosterol by coupling two high-resolution GC capillary columns. The columns, DB-17MS and DB-35MS, were coupled separately to a DB-5MS column. Total separation time of the authentic samples of oxysterols was 41 min for the DB-35MS/DB-5MS and 44 min for the DB-17MS/DB-5MS coupled columns. Two oil samples EBE1 and EBE2 extracted from exhausted bleaching earth collected from Europe were analyzed for oxysterol content by using these column combination systems. Both systems showed similar quantitative results; the total levels of oxysterols in these samples ranged from 2 to 3 mg/100 g. The prominent oxysterols were as follows: 7α-hydroxysterols (0.29–0.49 mg/100 g), 7β-hydroxysterols (0.13–0.68 mg/100 g) and 7-ketosterols (0.63–0.69 mg/100 g).
21.	Wiberg, Cedrik, 1989, et al. (författare) The electrochemical response of core-functionalized naphthalene Diimides (NDI) – a combined computational and experimental investigation 2021 Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 367 Tidskriftsartikel (refereegranskat)abstract © 2020 Aqueous organic redox flow batteries (AORFBs) have attracted increased interest as sustainable energy storage devices due to the desire of increasing electricity production from renewable energy sources. Several organic systems have been tested as redox active systems in AORFBs but few fundamental electrochemical studies exist. This article provides reduction potentials and acid constants, pKa, of nine different core-substituted naphthalene diimides (NDI), calculated using density functional theory (DFT). Reduction potentials were acquired at each oxidation state for the nine species and were used to achieve a correlation between the electron donating ability of the substituents and the potential. Cyclic voltammograms were simulated using the scheme-of-squares framework to include both electron and proton transfer processes. The results show that the anion radical is unprotonated in the entire pH range, while the dianion can be protonated in one or two steps depending on the substituent. The core substituents may also have acid-base properties. and optimization of the redox properties for battery applications can therefore be obtained both by changing the core substituent and by changing pH of the electrolyte. Three core-substituted NDI molecules were studied experimentally and good qualitative agreement with the theoretically predicted behaviour was demonstrated. For 2,6-di(dimethylamino)-naphthalene diimide (2DMA-NDI), the calculations showed that one of the DMA substituents could be protonated in the accessible pH range and pKa was determined to 3.95 using 1H NMR spectroscopy. The redox mechanism of each molecule was explored and the qualitative agreement between theory and experiment clearly shows that this combination provides a better understanding of the systems and offers opportunities for further developments. The applicability of NDI for redox flow batteries is finally discussed.
22.	Vucetic, Nemanja, et al. (författare) Tuned Bis-Layered Supported Ionic Liquid Catalyst (SILCA) for Competitive Activity in the Heck Reaction of Iodobenzene and Butyl Acrylate 2020 Ingår i: Catalysts. - : MDPI. - 2073-4344. ; 10:9 Tidskriftsartikel (refereegranskat)abstract A thorough experimental optimization of supported ionic liquid catalyst (SILCA) was performed in order to obtain a stable and efficient catalyst for the Heck reaction. Out of fifteen proposed structures, propyl imidazolium bromide-tetramethylguanidinium pentanoate modified SiO2 loaded with PdCl2 appeared to be the most stable and to have a good activity in the reaction between butylacrylate and iodobezene, resulting in a complete conversion in 40 min at 100 °C, in four consecutive experiments. This study elucidated on the stability of the catalytic system with an ionic liquid layer during the catalyst synthesis but also under reaction conditions. In the bis-layered catalyst, the imidazolium moiety as a part of internal layer, brought rigidity to the structure, while in external layer pentanoic acid gave sufficiently acidic carboxylic group capable to coordinate 1,1,3,3-tetramethylguanidine (TMG) and thus, allow good dispersion of Pd nanoparticles. The catalyst was characterized by means of XPS, FT-IR, TEM, ICP-OES, ζ-potential, EDX, TGA, and 13C NMR. The release and catch mechanism was observed, whereas Pd re-deposition can be hindered by catalyst poisoning and eventual loss of palladium.
23.	Wiberg, Cedrik, 1989, et al. (författare) Dimerization of 9,10-anthraquinone-2,7-Disulfonic acid (AQDS) 2019 Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686. ; 317, s. 478-485 Tidskriftsartikel (refereegranskat)abstract © 2019 Elsevier Ltd The redox flow battery is a leading candidate to supply society with large-scale energy storage. In the category of aqueous organic redox flow batteries, 9,10-anthraquinone-2,7-disulfonic acid (AQDS) is considered a top-performing molecule and shows ideal electrochemical behavior at low concentrations around 1 mM. However, its behavior at higher concentrations was rarely studied. In this work, the correlation between concentration and electrochemical capacity is evaluated for AQDS in 1 M H2SO4 and 1 M alkaline sodium carbonate buffer, employing cyclic voltammetry, rotating disk electrode voltammetry and diffusion NMR. It was found that an electrochemically inactive dimer was formed by the unreduced AQDS molecules, with dimerization equilibrium constants determined to be K = 5 M−1 for the acidic electrolyte and 8 M−1 for the alkaline one, significantly inhibiting full electrochemical utilization of the system. However, upon reduction of the bulk material, the dimerization will shift in favor of monomer or quinhydrone formation, possibly alleviating the impediment to reduction. Finally, it was found that the dimerization could be decreased slightly by increasing the temperature of the system.
24.	Hedlund, Artur, et al. (författare) Microstructures of cellulose coagulated in water and alcohols from 1-ethyl-3-methylimidazolium acetate : contrasting coagulation mechanisms 2019 Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 26:3, s. 1545-1563 Tidskriftsartikel (refereegranskat)abstract Abstract: Coagulation of cellulose solutions is a process whereby many useful materials with variable microstructures and properties can be produced. This study investigates the complexity of the phase separation that generates the structural heterogeneity of such materials. The ionic liquid, 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), and a co-solvent, dimethylsulfoxide (DMSO), are used to dissolve microcrystalline cellulose in concentrations from 5 to 25 wt%. The solutions are coagulated in water or 2-propanol (2PrOH). The coagulated material is then washed and solvent exchanged (water → 2PrOH → butanone → cyclohexane) in order to preserve the generated microstructures upon subsequent drying before analysis. Sweep electron microscopy images of 50 k magnification reveal open-pore fibrillar structures. The crystalline constituents of those fibrils are estimated using wide-angle X-ray spectroscopy and specific surface area data. It is found that the crystalline order or crystallite size is reduced by an increase in cellulose concentration, by the use of the co-solvent DMSO, or by the use of 2PrOH instead of water as the coagulant. Because previous theories cannot explain these trends, an alternative explanation is presented here focused on solid–liquid versus liquid–liquid phase separations. Graphical abstract: [Figure not available: see fulltext.].
25.	Sun, Bing, et al. (författare) Ion transport in polycarbonate based solid polymer electrolytes : experimental and computational investigations 2016 Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 18:14, s. 9504-9513 Tidskriftsartikel (refereegranskat)abstract Among the alternative host materials for solid polymer electrolytes (SPEs), polycarbonates have recently shown promising functionality in all-solid-state lithium batteries from ambient to elevated temperatures. While the computational and experimental investigations of ion conduction in conventional polyethers have been extensive, the ion transport in polycarbonates has been much less studied. The present work investigates the ionic transport behavior in SPEs based on poly(trimethylene carbonate) (PTMC) and its co-polymer with epsilon-caprolactone (CL) via both experimental and computational approaches. FTIR spectra indicated a preferential local coordination between Li+ and ester carbonyl oxygen atoms in the P(TMC20CL80) co-polymer SPE. Diffusion NMR revealed that the co-polymer SPE also displays higher ion mobilities than PTMC. For both systems, locally oriented polymer domains, a few hundred nanometers in size and with limited connections between them, were inferred from the NMR spin relaxation and diffusion data. Potentiostatic polarization experiments revealed notably higher cationic transference numbers in the polycarbonate based SPEs as compared to conventional polyether based SPEs. In addition, MD simulations provided atomic-scale insight into the structure-dynamics properties, including confirmation of a preferential Li+-carbonyl oxygen atom coordination, with a preference in coordination to the ester based monomers. A coupling of the Li-ion dynamics to the polymer chain dynamics was indicated by both simulations and experiments.
26.	Sznitko, L., et al. (författare) Low-threshold stimulated emission from lysozyme amyloid fibrils doped with a blue laser dye 2015 Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 106:2 Tidskriftsartikel (refereegranskat)abstract © 2015 AIP Publishing LLC. Amyloid fibrils are excellent self-assembling nanotemplates for organic molecules such as dyes. Here, we demonstrate that laser dye-doped lysozyme type fibrils exhibit significantly reduced threshold for stimulated emission compared to that observed in usual matrices. Laser action was studied in slab planar waveguides of the amyloids doped with Stilbene 420 laser dye prepared using a film casting technique. The lowering of the threshold of stimulated emission is analyzed in the context of intrinsic structure of the amyloid nanotemplates, electrostatic interaction of different microstructures with dye molecules, as well as material properties of the cast layers. All these factors are considered to be of importance for introducing gain for random laser operation.
27.	Lee, Kyuho, et al. (författare) Benchmarking van der Waals density functionals with experimental data: potential-energy curves for H2 molecules on Cu(111), (100) and (110) surfaces 2012 Ingår i: Journal of Physics: Condensed Matter. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 24:42 Tidskriftsartikel (refereegranskat)abstract Detailed physisorption data from experiment for the H2 molecule on low-index Cu surfaces challenge theory. Recently, density functional theory (DFT) has been developed to account for nonlocal correlation effects, including van der Waals (dispersion) forces. We show that the functional vdW-DF2 gives a potential-energy curve, potential-well energy levels and difference in lateral corrugation promisingly close to the results obtained by resonant elastic backscattering–diffraction experiments. The backscattering barrier is sensitive to the choice of exchange functional approximation. Further, the DFT-D3 and TS-vdW corrections to traditional DFT formulations are also benchmarked, and deviations are analyzed.
28.	Salvador, Christian Mark, 1989, et al. (författare) Indoor ozone/human chemistry and ventilation strategies 2019 Ingår i: Indoor Air. - : Hindawi Limited. - 1600-0668 .- 0905-6947. ; 29:6, s. 913-925 Tidskriftsartikel (refereegranskat)abstract This study aimed to better understand and quantify the influence of ventilation strategies on occupant-related indoor air chemistry. The oxidation of human skin oil constituents was studied in a continuously ventilated climate chamber at two air exchange rates (1 h-1 and 3 h-1 ) and two initial ozone mixing ratios (30 and 60 ppb). Additional measurements were performed to investigate the effect of intermittent ventilation ("off" followed by "on"). Soiled t-shirts were used to simulate the presence of occupants. A time-of-flight-chemical ionization mass spectrometer (ToF-CIMS) in positive mode using protonated water clusters was used to measure the oxygenated reaction products geranyl acetone, 6-methyl-5-hepten-2-one (6-MHO) and 4-oxopentanal (4-OPA). The measurement data were used in a series of mass balance models accounting for formation and removal processes. Reactions of ozone with squalene occurring on the surface of the t-shirts are mass transport limited; ventilation rate has only a small effect on this surface chemistry. Ozone-squalene reactions on the t-shirts produced gas-phase geranyl acetone, which was subsequently removed almost equally by ventilation and further reaction with ozone. About 70% of gas-phase 6-MHO was produced in surface reactions on the t-shirts, the remainder in secondary gas-phase reactions of ozone with geranyl acetone. 6-MHO was primarily removed by ventilation, while further reaction with ozone was responsible for about a third of its removal. 4-OPA was formed primarily on the surfaces of the shirts (~60%); gas-phase reactions of ozone with geranyl acetone and 6-MHO accounted for ~30% and ~10%, respectively. 4-OPA was removed entirely by ventilation. The results from the intermittent ventilation scenarios showed delayed formation of the reaction products and lower product concentrations compared to continuous ventilation.
29.	Alygizakis, Nikiforos, et al. (författare) Network analysis to reveal the most commonly detected compounds in predator-prey pairs in freshwater and marine mammals and fish in Europe 2024 Ingår i: Science of the Total Environment. - 0048-9697 .- 1879-1026. ; 950, s. 175303-175303 Tidskriftsartikel (refereegranskat)
30.	Kiraev, Salauat (författare) Unravelling Sensitisation and Quenching Pathways in Lanthanide Luminophores 2022 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract Lanthanide (Ln) ions find use in cellular detection and probing of many analytes, owing to their unique photophysical properties. However, to make the Ln emission efficient, one has to develop a light-harvesting antenna, which is an organic chromophore that absorbs and transfers energy to the Ln. By exciting the Ln complex, photoinduced electron transfer (PeT) from the antenna to the readily reducible Ln might occur. Usually, PeT is quenching Ln emission intensity. Thus, the work herein aims to evaluate and distinguish sensitising and quenching pathways in Ln emission to improve the brightness of Ln luminophores for biological applications.After presenting an introduction to Ln photophysics and sensitisation in chapter 1, chapter 2 describes our work on Ln octa- and nonacoordinate complexes bearing the same antenna. We demonstrated that the azide and alkyne reactive groups could be attached to the antenna to make Ln complexes bioconjugable. The saturation of the Ln coordination environment resulted in intraligand PeT, which cancelled out the benefits of eliminated quenching from the coordinated water molecule.To study the effect of photoredox quenching in Eu emission, we focused on tuning reduction potentials for a possible response in luminescence properties in chapter 3. Increasing positive charges of complexes destabilised Eu3+ and decreased Ln emission quantum yields. This behaviour was due to PeT quenching of the more readily reducible Eu under similar sensitisation conditions. Fluoride binding boosted Ln emission intensity in the least Eu3+-stabilising ligand field.In chapter 4, the role of a tertiary amide linker between the antenna and the metal binding site was examined. For poorly emissive coumarin-appended complexes quenching via photoinduced reduction of Eu from the antenna was unlikely, while in carbostyril-sensitised complexes PeT was efficient.Ln compounds with lower ligand denticity allowed better fluoride detection via the increased effect of PeT quenching and the larger number of water molecules, as shown in chapter 5. However, the presence of cyanide significantly quenched Eu emissions of the same complexes, making it possible to distinguish cyanide from fluoride.Chapters 6‒7 were devoted to the sensitisation of Yb luminescence. The NIR emission intensity increased marginally in the complexes with efficient PeT. The main sensitising effect originated from phonon-assisted energy transfer favourable in our Yb complexes. When picolinate donors stimulated intraligand PeT, detrimental to the ligand fluorescence in Yb compounds, Yb emission was noticeably more intense than in the first series without picolinates.
31.	Lundborg, Lina, 1986-, et al. (författare) Conifer chemical defenses influence meal properties of the pine weevil Hylobius abietis Annan publikation (övrigt vetenskapligt/konstnärligt)abstract Chemical defenses of conifers can be experimentally activated to respond more efficiently to feeding damage by insects. One chemical elicitor that triggers plant defenses, and thereby protects conifers, is methyl jasmonate (MeJA). However, there is little known about the associations between MeJA-induced conifer defenses, and the meal properties of phytophagous insects. To address this knowledge gap, we have analyzed relations between volatile contents of Scots pine (Pinus sylvestris L.) tissues, and meal properties of the pine weevil (Hylobius abietis (L.)). Phloem and needles (both weevil target tissues) from MeJA-treated and control seedlings were extracted by n-hexane and analyzed by two-dimensional gas chromatography-mass spectrometry (2D GC-MS). Feeding of pine weevils on seedlings from the same batches were video-recorded to determine meal properties. Multivariate statistical analyses showed that phloem and needle contents of MeJA-treated seedlings had different volatile compositions from the control seedlings. Levels of (+)-α-pinene were high, and levels of the antifeedant 2-phenylethanol were low, in phloem of control seedlings with feeding damage. Accordingly, pine weevils fed more slowly and had shorter meals on MeJA-treated seedlings. In addition, the chemical compositions of phloem and needles – and accordingly weevil meal durations on them – were more similar in MeJA-treated seedlings than in controls. The results illustrate that detailed knowledge of insect responses can help efforts to identify and elucidate specific roles of resistance agents in complex chemical profiles.
32.	Lundborg, Lina, 1986-, et al. (författare) Constitutive and MeJA-induced terpenes in Pinus pinaster and Pinus radiata in relation to Hylobius abietis Annan publikation (övrigt vetenskapligt/konstnärligt)abstract The feeding preference of the pine weevil to Maritime pine (Pinus pinaster Ait.) and Monterey pine (Pinus radiata D. Don) differ in laboratory tests and in the field: Can this be explained by the volatile compounds released by the seedlings? Understanding the interaction between the chemical defenses of young pines and feeding preferences of the pine weevil (Hylobius abietis (L.)) may improve protection methods of conifer seedlings in Europe and Asia. In order to increase the resistance of seedlings of P. pinaster and P. radiata, these were treated with the chemical elicitor methyl jasmonate (MeJA). The effects of the MeJA treatments on the amounts and composition of volatile terpenes in tissues (needles and phloem) were investigated by extracting these in hexane, whereafter the volatile constituents of the extracts were separated and identified by gas chromatography-mass spectrometry (GC-MS). In addition, the most abundant monoterpenes (α-pinene and β-pinene) were separated on a chiral column in their enantiomers. Already at the lowest concentration of MeJA treatment, 5 mM, the amounts of volatile terpenes in the needles of P. radiata increased and the seedling heights were reduced. In P. pinaster, on the other hand, no effect from the MeJA treatment was observed on the total volatile terpenes in the needles, and only at the strongest MeJA concentration, the seedling heights were affected. In the phloem of P. pinaster the composition of volatile contents, changed after MeJA treatment, showing a reduction in the (+)-α-pinene. In contrast, the amounts of (+)-α-pinene increased in P. radiata. In a previous study, controls and MeJA-treated pine seedlings, from the same MeJA treatment batches as in this study, were subjected to a field trial. In the field, the pine weevils preferred the seedlings of P. radiata over those of P. pinaster. We propose that the differences in induction of (+)-α-pinene may be important for explaining the differences in pine weevil feeding preferences.
33.	Lundborg, Lina, 1986- (författare) Effects of methyl jasmonate on chemical defenses of conifer seedlings in relation to feeding by Hylobius abietis 2016 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract The chemical elicitor methyl jasmonate (MeJA) could replace insecticides in Europe and Asia for protection of young conifers against the pine weevil (Hylobius abietis). This thesis mainly focuses on the effects of MeJA treatment on chemical defenses of conifers from seedling batches with documented field resistance. Tissues of three pine species and one spruce species, with various treatments, were here extracted in hexane, whereafter volatile contents of tissues were separated and analyzed by 2D GC-MS.Induced responses of seedlings of Maritime pine (Pinus pinaster) and Monterey pine (Pinus radiata) to the folivore pine processionary (Thaumetopoea pityocampa), and the phloem-feeder H. abietis, have been studied. Amounts of mono- and sesqui-terpenes (and also non-volatile resin) in conifer tissues (needles and phloem) were less induced by T. pityocampa than by H. abietis.The MeJA-treated seedlings of Scots pine (Pinus sylvestris) changed their composition of phloem monoterpenes (induction of (-)-β-pinene), and were better protected in field than the seedlings of Norway spruce (Picea abies), which increased their total amounts of monoterpenes. Orientation bioassays with H. abietis showed deterrent effects of (-)-β-pinene, (+)-3-carene, (-)-bornyl acetate and 1,8-cineole. Conversely, (-)-α-pinene (induced in P. abies but not in P. sylvestris) was non-deterrent.MeJA-treated seedlings fed on by H. abietis contained higher amounts of the H. abietis antifeedant 2-phenylethanol, in tissues and emissions. Phloem of control seedlings instead induced the (+)-α-pinene, which is one of the enantiomers of the H. abietis attractant α-pinene.In response to MeJA treatment, the relative amounts of the (+)-α-pinene increased in the phloem of P. radiata, while it decreased in P. pinaster phloem. The preference of H. abietis in the field for P. radiata before P. pinaster may be explained by these changes in enantiomers of the H. abietis attractant α-pinene.
34.	Lundborg, Lina, 1986-, et al. (författare) Induced defenses change the chemical composition of pine seedlings and influence meal properties of the pine weevil Hylobius abietis 2016 Ingår i: Phytochemistry. - : Elsevier. - 0031-9422 .- 1873-3700. ; 130, s. 99-105 Tidskriftsartikel (refereegranskat)abstract The defense of conifers against phytophagous insects relies to a large extent on induced chemical defenses. However, it is not clear how induced changes in chemical composition influence the meal properties of phytophagous insects (and thus damage rates). The defense can be induced experimentally with methyl jasmonate (MeJA), which is a substance that is produced naturally when a plant is attacked. Here we used MeJA to investigate how the volatile contents of Scots pine (Pinus sylvestris L.) tissues influence the meal properties of the pine weevil (Hylobius abietis (L.)). Phloem and needles (both weevil target tissues) from MeJA-treated and control seedlings were extracted by n-hexane and analyzed by two-dimensional gas chromatography-mass spectrometry (2D GC-MS). The feeding of pine weevils on MeJA-treated and control seedlings were video-recorded to determine meal properties. Multivariate statistical analyses showed that phloem and needle contents of MeJA-treated seedlings had different volatile compositions compared to control seedlings. Levels of the pine weevil attractant (+)-α-pinene were particularly high in phloem of control seedlings with feeding damage. The antifeedant substance 2-phenylethanol occurred at higher levels in the phloem of MeJA-treated than in control seedlings. Accordingly, pine weevils fed slower and had shorter meals on MeJA-seedlings. The chemical compositions of phloem and needle tissues were clearly different in control seedlings but not in the MeJA-treated seedlings. Consequently, meal durations of mixed meals, i.e. both needles and phloem, were longer than phloem meals on control seedlings, while meal durations on MeJA seedlings did not differ between these meal contents. The meal duration influences the risk of girdling and plant death. Thus our results suggest a mechanism by which MeJA treatment may protect conifer seedlings against pine weevils.
35.	Lundborg, Lina, 1986-, et al. (författare) Methyl jasmonate-induced monoterpenes in Scots pine and Norway spruce tissues affect pine weevil orientation Annan publikation (övrigt vetenskapligt/konstnärligt)abstract In large parts of Europe insecticide-free measures for protecting conifer plants are desired to suppress damage by the pine weevil Hylobius abietis (L.). Treatment with methyl jasmonate (MeJA), a chemical elicitor already used in crop production, may enhance expression of chemical defenses in seedlings in conifer regenerations. However, in a previous experiment MeJA treatment resulted in substantially better field protection for Scots pine (Pinus sylvestris L.) than for Norway spruce (Picea abies (L.) Karst.). Hypothesizing that the variations may be at least partly due to volatiles released by MeJA-treated seedlings and their effects on pine weevil orientation, we examined tissue extracts of seedlings (from the same batches as previously used) by two-dimensional GC-MS. We found that the MeJA treatment increased contents of the monoterpene (-)-β-pinene in phloem (the weevil’s main target tissue) of both tree species, however, the (-)-β-pinene/(-)-α-pinene ratio increased more in the phloem of P. sylvestris. We also tested the attractiveness of individual monoterpenes found in conifer tissues (needles and phloem) for pine weevils using an arena with traps baited with single-substance dispensers and pine twigs. Trap catches were reduced when the pine material was combined with a dispenser releasing (-)-β-pinene, (+)-3-carene, (-)-bornyl acetate or 1,8-cineole. However, (-)-α-pinene did not have this effect. Thus, the greater field protection of MeJA-treated P. sylvestris seedlings may be due to the selective induction of increases in contents of the deterrent (-)-β-pinene, in contrast to strong increases in both non-deterrent (-)-α-pinene and the deterrent (-)-β-pinene in P. abies seedlings.
36.	Zhao, Yun, et al. (författare) Rational design of functional binder systems for high-energy lithium-based rechargeable batteries 2021 Ingår i: Energy Storage Materials. - : Elsevier. - 2405-8289 .- 2405-8297. ; 35, s. 353-377 Tidskriftsartikel (refereegranskat)abstract Binders, which maintain the structural integrity of electrodes, are critical components of lithium-based rechargeable batteries (LBRBs) that significantly affect battery performances, despite accounting for 2 to 5 wt% (up to 5 wt% but usually 2 wt%) of the entire electrode. Traditional polyvinylidene fluoride (PVDF) binders that interact with electrode components via weak van der Waals forces are effective in conventional LBRB systems (graphite/LiCoO2, etc.). However, its stable fluorinated structures limit the potential for further functionalization and inhibit strong interactions towards external substances. Consequently, they are unsuitable for next-generation battery systems with high energy density. There is thus a need for new functional binders with facile features compatible with novel electrode materials and chemistries. Here in this review we consider the strategies for rationally designing these functional binders. On the basis of fundamental understandings of the issues for high-energy electrode materials, we have summarized seven desired functions that binders should possess depending on the target electrodes where the binders will be applied. Then a variety of leading-edge functional binders are reviewed to show how their chemical structures realize these above functions and how the employment of these binders affects the cell's electrochemical performances. Finally the corresponding design strategies are therefore proposed, and future research opportunities as well as challenges relating to LBRB binders are outlined.
37.	Mousavinejad, Atiyeh, et al. (författare) Nickel-Based Metal–Organic Frameworks to Improve the CO2/CH4 Separation Capability of Thin-Film Pebax Membranes 2020 Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 59:28, s. 12834-12844 Tidskriftsartikel (refereegranskat)abstract Incorporating metal–organic frameworks (MOFs) into the thin layer of thin-film composite (TFC) membranes is an effective way of improving the CO2/CH4 separation performance. In this study, porous polyethersulfone (PES) membranes were surface-coated with a novel CO2-permeable layer consisting of CO2-philic Pebax and nickel-based MOF particles. The MOF particles were synthesized using nickel(II) acetate tetrahydrate as a metal source and 2-amino-1,4-dicarboxybenzene (NH2-BDC) as an organic linker. The properties and performance of the MOFs and synthesized membranes were assessed using analytical techniques including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM), and dynamic light scattering (DLS). DLS analysis showed that the MOF particle size range was in a range of 350–650 nm. Moreover, cross-sectional FE-SEM images depicted that a uniform and dense Pebax layer was shaped on top of the PES substrate. Well dispersion of the particles was demonstrated by surface FE-SEM imaging. DSC analysis showed that embedding Ni-NH2-BDC MOF particles into the Pebax-1657 film increased the crystallinity degree and the glass-transition temperature (Tg) of resulted membranes. To evaluate the membrane’s separation performance, permeation experiments were performed with CO2, CH4, and CO2/CH4 mixtures at ambient temperature. Embedding 5 wt % Ni-based MOF particles improved the CO2 permeability and CO2/CH4 selectivity from 19.05 Barrer and 32.2 to 31.55 Barrer and 94, respectively, compared to MOF-free membranes. Loading MOF particles into the Pebax matrix also improved the real gas separation factor. The obtained results demonstrate the great potential of the fabricated TFC membranes for gas separation.
38.	Tehrani, Ali, 1976, et al. (författare) Solubilization of hydrophobic dyes in surfactant solutions 2013 Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 6:2, s. 580-608 Forskningsöversikt (refereegranskat)abstract In this paper, the use of surfactants for solubilization of hydrophobic organic dyes (mainly solvent and disperse dyes) has been reviewed. The effect of parameters such as the chemical structures of the surfactant and the dye, addition of salt and of polyelectrolytes, pH, and temperature on dye solubilization has been discussed. Surfactant self-assemble into micelles in aqueous solution and below the concentration where this occurs-the critical micelle concentration (CMC)-there is no solubilization. Above the CMC, the amount of solubilized dye increases linearly with the increase in surfactant concentration. It is demonstrated that different surfactants work best for different dyes. In general, nonionic surfactants have higher solubilization power than anionic and cationic surfactants. It is likely that the reason for the good performance of nonionic surfactants is that they allow dyes to be accommodated not only in the inner, hydrocarbon part of the micelle but also in the headgroup shell. It is demonstrated that the location of a dye in a surfactant micelle can be assessed from the absorption spectrum of the dye-containing micellar solution.
39.	Garmash, O., et al. (författare) Multi-generation OH oxidation as a source for highly oxygenated organic molecules from aromatics 2020 Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 20:1, s. 515-537 Tidskriftsartikel (refereegranskat)abstract Recent studies have recognised highly oxygenated organic molecules (HOMs) in the atmosphere as
40.	Zhou, Yu, et al. (författare) Unveiling the Interfacial Effects for Enhanced Hydrogen Evolution Reaction on MoS2/WTe2 Hybrid Structures 2019 Ingår i: Small. - : Wiley-VCH Verlagsgesellschaft. - 1613-6810 .- 1613-6829. ; 15:19 Tidskriftsartikel (refereegranskat)abstract Using the MoS2-WTe2 heterostructure as a model system combined with electrochemical microreactors and density function theory calculations, it is shown that heterostructured contacts enhance the hydrogen evolution reaction (HER) activity of monolayer MoS2. Two possible mechanisms are suggested to explain this enhancement: efficient charge injection through large-area heterojunctions between MoS2 and WTe2 and effective screening of mirror charges due to the semimetallic nature of WTe2. The dielectric screening effect is proven minor, probed by measuring the HER activity of monolayer MoS2 on various support substrates with dielectric constants ranging from 4 to 300. Thus, the enhanced HER is attributed to the increased charge injection into MoS2 through large-area heterojunctions. Based on this understanding, a MoS2/WTe2 hybrid catalyst is fabricated with an HER overpotential of -140 mV at 10 mA cm(-2), a Tafel slope of 40 mV dec(-1), and long stability. These results demonstrate the importance of interfacial design in transition metal dichalcogenide HER catalysts. The microreactor platform presents an unambiguous approach to probe interfacial effects in various electrocatalytic reactions.
41.	Arvidsson, Adam, 1990 (författare) Partial methane oxidation from electronic structure calculations 2017 Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract Investigating catalytic reactions with computational methods is a powerful approach to understand fundamental aspects of catalytic reactions and find ways to guide catalytic design. Partial methane oxidation is one example of a reaction with intriguing challenges, where a detailed atomistic approach may help to unravel the bottlenecks of this, as of yet, inefficient reaction. Although methane only needs one oxygen atom for conversion to methanol, the direct oxidation is difficult; it is in fact so difficult that at many oil extraction sites, the methane that inevitably accompanies the crude oil is flared into carbon dioxide and water as gas-phase methane is too inconvenient to store and transport.The main challenge with partial oxidation of methane is to selectively control the oxidation and steer it towards methanol and prevent over-oxidation to CO2. There exist natural enzymes that can partially oxidize methane to methanol at ambient pressure and temperature, although very slowly. One inorganic analogue to these naturally occurring enzymes are zeolites, a porous material that can readily be synthesized and that have been shown to convert methane to methanol at ambient conditions with a high selectivity (>90 %). This has been realized for zeolites ion-exchanged with different metals, such as iron, cobalt, nickel, and copper. Although there have been many attempts to determine the active site for the reaction, there is still no consensus. One candidate that has been put forth is a [Cu-O-Cu]2+ motif experimentally characterized in the ZSM-5 zeolite. In this thesis, partial oxidation of methane is investigated, focusing on this dimer motif. By combining density functional theory calculations with microkinetic modelling, the catalytic performance of the dimer motif is investigated with a simple reaction mechanism for copper, but also with the copper atoms exchanged with nickel, cobalt, iron, silver, or gold. From these results, it is clear that this particular dimer site is a relevant candidate only for copper, and can be excluded in the continued search for active sites in nickel, cobalt, and iron ion-exchanged ZSM-5.To further understand how methanol is formed and interacts with Cu-ZSM-5, experimental and calculated infrared frequencies are compared for methanol and other adsorbates. The partial oxidation of methane is also studied for other systems with oxidants other than oxygen. In particular, methane oxidation with H2S to CH3SH and H2 is explored on molybdenum sulfide clusters.
42.	Khokarale, Santosh G., et al. (författare) One-Pot, Metal-Free Synthesis of Dimethyl Carbonate from CO2 at Room Temperature 2020 Ingår i: Sustainable Chemistry. - : MDPI. - 2673-4079. ; 1:3, s. 298-314 Tidskriftsartikel (refereegranskat)abstract Herein, we report on the metal-free, one-pot synthesis of industrially important dimethyl carbonate (DMC) from molecular CO2 under ambient conditions. In this process, initially the CO2 was chemisorbed through the formation of a switchable ionic liquid (SIL), [DBUH] [CH3CO3], by the interaction of CO2 with an equivalent mixture of organic superbase 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) and methanol. The obtained SIL further reacted with methyl iodide (CH3I) to form DMC. The synthesis was carried out in both dimethyl sulfoxide (DMSO) and methanol. Methanol is preferred, as it not only served as a reagent and solvent in CO2 capture and DMC synthesis, but it also assisted in controlling the side reactions between chemical species such as CH3I and [DBUH]+ cation and increased the yield of DMC. Hence, the use of methanol avoided the loss of captured CO2 and favored the formation of DMC with high selectivity. Under the applied reaction conditions, 89% of the captured CO2 was converted to DMC. DBU was obtained, achieving 86% recovery of its salts formed during the synthesis. Most importantly, in this report we describe a simple and renewable solvent-based process for a metal-free approach to DMC synthesis under industrially feasible reaction conditions.
43.	Liu, Yuan (författare) Theoretical Studies of Natural Gas Hydrates and H-bonded Clusters and Crystals 2016 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract In this thesis H-bonded systems (natural gas hydrates, water clusters, and crystal ice) are studied by density functional theory (DFT) computations.Natural gas hydrates (NGHs) play an important role in energy and environmental fields: NGHs are considered as a promising backup energy resource in the near-future due to their tremendous carbon content; improper exploration of NGHs could induce geological disasters and aggravate the greenhouse effect. In addition, many technologies based on gas hydrates are being applied and developed. The thermodynamic stabilities of various water cavities in different clathrate crystalline phases occupied by hydrocarbon gas molecules are studied by dispersion-corrected hybrid functionals. The Raman spectra of C-C and C-H stretching vibrations of hydrocarbon molecules in various water cavities in the solid state are derived. The trends of C-H stretching vibrational frequencies are found to follow the prediction by the “loose cage ─\| tight cage” model. In addition, the trends and origins of 13C NMR chemical shifts of hydrocarbon molecules in various NGHs are presented. These theoretical results will enlarge the database of C-C and C-H stretching vibrational frequencies and 13C NMR parameters of hydrocarbon molecules in NGHs, and provide valuable information to help identify the types of clathrate phases and varieties of guest molecules included in NGHs samples taken from natural sites.The behavior of water clusters may help to understand the properties of its liquid and solid states. The thermodynamic stabilities and IR spectra of a small-, medium-, and large-sized water cluster are studied in this work. After full optimization of (H2O)20,54,100 using the hybrid functional B3LYP, the electronic energies, zero-point energies, internal energies, enthalpies, entropies, and Gibbs free energies of the water clusters are computed. The OH stretching vibrational IR spectra of (H2O)20,54,100 are also presented and split into sub-spectra for different H-bond types based on the specific contributions from each group. It is found that the OH stretching vibrational frequencies of water are sensitive to the conformations of the H-bonds and the vibrations of the H-bonds belonging to different types are located in separated regions in the IR spectra. Thus, the spectroscopic fingerprints will reflect the H-bond topology of the water molecules in a water cluster.Ice XI has been suggested to be involved in the process of planetary formation as a considerable electric field might be formed from the ferroelectric ice XI in space. IR and Raman spectroscopic technology can be directly used to identify the occurrence of ferroelectric ice XI in laboratory or extraterrestrial settings. Due to the difficulty for DFT to describe non-covalent systems, the performance of 16 different DFT methods applied on the ice Ih, VIII, IX, and XI crystal phases are assessed. Based on the computational accuracy and cost, the IR and Raman spectra of ice Ih and XI are derived and compared. The librational vibrations are found to be the identifier which can be used to distinguish ice Ih and ice XI in the universe. In addition, the existence only one kind of H-bond in ice Ih is demonstrated from the overlapping sub-spectra for different types of H-bonded pair configurations in 16 isomers of ice Ih.The region of water under negative pressure is an exotic land in lack of exploitation. Guest free clathrate hydrate (clathrate ice) of sII type has been recently confirmed experimentally at negative pressure. Does any other clathrate ice phase exist at negative pressure region? Since clathrate hydrate are isostructural with silica clathrate minerals and semiconductor clathrates, and crystal structure prediction by analogy with known structures and first-principles computations is an effective way to find new crystalline phases of solid materials, we are motived to look for new clathrate ice phases from silica or semiconductor clathrate materials based on first-principles computations. Borrowing the idea new clathrate frameworks of ZnO and SiC can be constructed by connecting their bubble clusters in different ways, new clathrate ice phases (sL, sL_I, sL_II, and sL_III) are generated by connecting the water bubble clusters according to different rules. Using the non-local dispersion-corrected vdW-DF2 functional, clathrate ice sL with ultralow density (0.6 g/cm3) is predicted by first-principles phase diagram computations to be stable under larger negative pressures than the sII phase. The phase diagram of water is thus extended into the lower negative pressure region.
44.	Xianchan, Li, 1982, et al. (författare) Electrochemical quantification of transmitter concentration in single nanoscale vesicles isolated from PC12 cells 2018 Ingår i: Faraday Discussions. - : Royal Society of Chemistry (RSC). - 1359-6640 .- 1364-5498. ; 210, s. 353-364 Tidskriftsartikel (refereegranskat)abstract We use an electrochemical platform, nanoparticle tracking analysis, and differential centrifugation of single catecholamine vesicles to study the properties of nanometer transmitter vesicles, including the number of molecules, size, and catecholamine concentration inside. Vesicle impact electrochemical cytometry (VIEC) was used to quantify the catecholamine content of single vesicles in different batches isolated from pheochromocytoma (PC12) cells with different ultracentrifugation speeds. We show that, vesicles containing less catecholamine are obtained at subsequent centrifugation steps with higher speed (force). Important to quantification, the cumulative content after subsequent centrifugation steps is equivalent to that of one-step centrifugation at the highest speed, 70,000g. Moreover, as we count molecules in the vesicles, we compared molecular numbers from VIEC, flow VIEC, and intracellular VIEC to corresponding vesicle size measured by nanoparticle tracking analysis to evaluate catecholamine concentration in vesicles. The data suggest that vesicular catecholamine concentration is relatively constant and independent of the vesicular size, indicating vesicular transmitter content as a main factor regulating the vesicle size.
45.	Hagman, Benjamin, et al. (författare) Steps Control the Dissociation of CO2 on Cu(100) 2018 Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 140:40, s. 12974-12979 Tidskriftsartikel (refereegranskat)abstract CO2 reduction reactions, which provide one route to limit the emission of this greenhouse gas, are commonly performed over Cu-based catalysts. Here, we use ambient pressure X-ray photoelectron spectroscopy together with density functional theory to obtain an atomistic understanding of the dissociative adsorption of CO2 on Cu(100). We find that the process is dominated by the presence of steps, which promote both a lowering of the dissociation barrier and an efficient separation between adsorbed O and CO, reducing the probability for recombination. The identification of steps as sites for efficient CO2 dissociation provides an understanding that can be used in the design of future CO2 reduction catalysts.
46.	Heydari, Golrokh, 1982-, et al. (författare) Temperature-Dependent Deicing Properties of ElectrostaticallyAnchored Branched Brush Layers of Poly(ethylene oxide) 2016 Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 32:17, s. 4194-4202 Tidskriftsartikel (refereegranskat)abstract The hydration water of hydrophilic polymersfreezes at subzero temperatures. The adsorption of suchpolymers will result in a hydrophilic surface layer that stronglybinds water. Provided this interfacial hydration water remainsliquidlike at subzero temperatures, its presence could possiblyreduce ice adhesion, in particular, if the liquidlike layer isthicker than or comparable to the surface roughness. Toexplore this idea, a diblock copolymer, having one branchedbottle-brush block of poly(ethylene oxide) and one linear cationic block, was electrostatically anchored on flat silica surfaces. Theshear ice adhesion strength on such polymer-coated surfaces was investigated down to −25 °C using a homebuilt device. Inaddition, the temperature dependence of the ice adhesion on surfaces coated with only the cationic block, only the branchedbottle-brush block, and with linear poly(ethylene oxide) was investigated. Significant ice adhesion reduction, in particular, attemperatures above −15 °C, was observed on silica surfaces coated with the electrostatically anchored diblock copolymer.Differential scanning calorimetry measurements on bulk polymer solutions demonstrate different thermal transitions of waterinteracting with branched and linear poly(ethylene oxide) (with hydration water melting points of about −18 and −10 °C,respectively). This difference is consistent with the low shear ice adhesion strength measured on surfaces carrying branchedbottle-brush structured poly(ethylene oxide) at −10 °C, whereas no significant adhesion reduction was obtained with linearpoly(ethylene oxide) at this temperature. We propose a lubrication effect of the hydration water bound to the branched bottlebrushstructured poly(ethylene oxide), which, in the bulk, does not freeze until −18 °C.
47.	Bengtsson, Katarina (författare) Electrokinetic devices from polymeric materials 2017 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract There are multiple applications for polymers: our bodies are built of them, plastic bags and boxes used for storage are composed of them, as are the shells for electronics, TVs, computers, clothes etc. Many polymers are cheap, and easy to manufacture and process which make them suitable for disposable systems. The choice of polymer to construct an object will therefore highly influence the properties of the object itself. The focus of this thesis is the application of commonly used polymers to solve some challenges regarding integration of electrodes in electrokinetic devices and 3D printing.The first part of this thesis regards electrokinetic systems and the electrodes’ impact on the system. Electrokinetic systems require Faradaic (electrochemical) reactions at the electrodes to maintain an electric field in an electrolyte. The electrochemical reactions at the electrodes allow electron-to-ion transduction at the electrode-electrolyte interface, necessary to drive a current at the applied potential through the system, which thereby either cause flow (electroosmosis) or separation (electrophoresis). These electrochemical reactions at the electrodes, such as water electrolysis, are usually problematic in analytical systems and systems applied in biology. One solution to reduce the impact of water electrolysis is by replacing metal electrodes with electrochemically active polymers, e.g. poly(3,4-ethylenedioxythiophene) (PEDOT). Paper 1 demonstrates that PEDOT electrodes can replace platinum electrodes in a gel electrophoretic setup. Paper 2 reports an all-plastic, planar, flexible electroosmotic pump which continuously transports water from one side to the other using potentials as low as 0.3 V. This electroosmotic pump was further developed in paper 3, where it was made into a compact and modular setup, compatible with commercial microfluidic devices. We demonstrated that the pump could maintain an alternating flow for at least 96 h, with a sufficient flow of cell medium to keep cells alive for the same period of time.The second part of the thesis describes the use of 3D printers for manufacturing prototypes and the material requirements for 3D printing. Protruding and over-hanging structures are more challenging to print using a 3D printer and usually require supporting material during the printing process. In paper 4, we showed that polyethylene glycol (PEG), in combination with a carbonate-based plasticizer, functions well as a 3D printable sacrificial template material. PEG2000 with between 20 and 30 wt% dimethyl carbonate or propylene carbonate have good shear-thinning rheology, mechanical and chemical stability, and water solubility, which are advantageous for a supporting material used in 3D printing.The advances presented in this thesis have solved some of the challenges regarding electrokinetic systems and prototype manufacturing. Hopefully this will contribute to the development of robust, disposable, low-cost, and autonomous electrokinetic devices.
48.	Armanious, Antonius, 1981, et al. (författare) Determination of Nanosized Adsorbate Mass in Solution Using Mechanical Resonators: Elimination of the So Far Inseparable Liquid Contribution 2021 Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 125:41, s. 22733-22746 Tidskriftsartikel (refereegranskat)abstract Assumption-free mass quantification of nanofilms, nanoparticles, and (supra)molecular adsorbates in a liquid environment remains a key challenge in many branches of science. Mechanical resonators can uniquely determine the mass of essentially any adsorbate; yet, when operating in a liquid environment, the liquid dynamically coupled to the adsorbate contributes significantly to the measured response, which complicates data interpretation and impairs quantitative adsorbate mass determination. Employing the Navier-Stokes equation for liquid velocity in contact with an oscillating surface, we show that the liquid contribution for rigid systems can be eliminated by measuring the response in solutions with identical kinematic viscosity but different densities. Guided by this insight, we used the quartz crystal microbalance (QCM), one of the most widely employed mechanical resonators, to experimentally demonstrate that the kinematic-viscosity matching can be utilized to quantify the dry mass of rigid and in many cases also nonrigid adsorbate systems, including, e.g., rigid nanoparticles, tethered biological nanoparticles (lipid vesicles), as well as highly hydrated polymeric films. For all the adsorbates, the dry mass determined using the kinematic-viscosity matching was within the uncertainty limits of the corresponding mass determined using complementary methods, i.e., QCM in air, scanning electron microscopy, surface plasmon resonance, and theoretical estimations. The same approach applied to the simultaneously measured energy dissipation made it possible to quantify the mechanical properties of the adsorbate and its attachment to the surface, as demonstrated by, for example, probing the hydrodynamic stabilization induced by nanoparticle crowding. In addition to a unique means to quantify the liquid contribution to the measured response of mechanical resonators, we also envision that the kinematic-viscosity-matching approach will open up applications beyond mass determination, including a new means to investigate orientation, spatial distribution, and binding strength of adsorbates without the need for complementary techniques.
49.	Barker, David, 1993, et al. (författare) Filter function of graphene oxide: Trapping perfluorinated molecules 2020 Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 1089-7690 .- 0021-9606. ; 152:2 Tidskriftsartikel (refereegranskat)abstract We need clean drinking water, but current water purification methods are not always sufficient. This study examines the binding and binding mechanisms when graphene oxide is used as a filter material for removing perfluorinated substances and trihalomethanes. We use density functional theory calculations to examine the binding of the harmful molecules on graphene oxide. Our results indicate that the binding energies between graphene oxide and the investigated molecules are in the range of 370-1450 meV per molecule, similar to the binding energies obtained in other studies, where adsorption of similar size molecules onto graphene oxide has been investigated. This indicates that graphene oxide has the potential to separate the molecules of interest from the water. Significant contribution to the binding energies comes from the van der Waals (dispersion) interaction between the molecule and graphene oxide, while the hydrogen bonding between the functional groups of graphene oxide and the hydrogen atoms in functional groups on the molecules also plays a role in the binding.
50.	Carlsson, P. T. M., et al. (författare) Comparison of isoprene chemical mechanisms under atmospheric night-time conditions in chamber experiments: evidence of hydroperoxy aldehydes and epoxy products from NO3 oxidation 2023 Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 23:5, s. 3147-3180 Tidskriftsartikel (refereegranskat)abstract The gas-phase reaction of isoprene with the nitrate radical (NO3) was investigated in experiments in the outdoor SAPHIR chamber under atmospherically relevant conditions specifically with respect to the chemical lifetime and fate of nitrato-organic peroxy radicals (RO2). Observations of organic products were compared to concentrations expected from different chemical mechanisms: (1) the Master Chemical Mechanism, which simplifies the NO3 isoprene chemistry by only considering one RO2 isomer; (2) the chemical mechanism derived from experiments in the Caltech chamber, which considers different RO2 isomers; and (3) the FZJ-NO3 isoprene mechanism derived from quantum chemical calculations, which in addition to the Caltech mechanism includes equilibrium reactions of RO(2 )isomers, unimolecular reactions of nitrate RO(2 )radicals and epoxidation reactions of nitrate alkoxy radicals. Measurements using mass spectrometer instruments give evidence that the new reactions pathways predicted by quantum chemical calculations play a role in the NO3 oxidation of isoprene. Hydroperoxy aldehyde (HPALD) species, which are specific to unimolecular reactions of nitrate RO2, were detected even in the presence of an OH scavenger, excluding the possibility that concurrent oxidation by hydroxyl radicals (OH) is responsible for their formation. In addition, ion signals at masses that can be attributed to epoxy compounds, which are specific to the epoxidation reaction of nitrate alkoxy radicals, were detected. Measurements of methyl vinyl ketone (MVK) and methacrolein (MACR) concentrations confirm that the decomposition of nitrate alkoxy radicals implemented in the Caltech mechanism cannot compete with the ring-closure reactions predicted by quantum chemical calculations. The validity of the FZJ-NO3 isoprene mechanism is further supported by a good agreement between measured and simulated hydroxyl radical (OH) reactivity. Nevertheless, the FZJ-NO3 isoprene mechanism needs further investigations with respect to the absolute importance of unimolecular reactions of nitrate RO2 and epoxidation reactions of nitrate alkoxy radicals. Absolute concentrations of specific organic nitrates such as nitrate hydroperoxides would be required to experimentally determine product yields and branching ratios of reactions but could not be measured in the chamber experiments due to the lack of calibration standards for these compounds. The temporal evolution of mass traces attributed to product species such as nitrate hydroperoxides, nitrate carbonyl and nitrate alcohols as well as hydroperoxy aldehydes observed by the mass spectrometer instruments demonstrates that further oxidation by the nitrate radical and ozone at atmospheric concentrations is small on the timescale of one night (12 h) for typical oxidant concentrations. However, oxidation by hydroxyl radicals present at night and potentially also produced from the decomposition of nitrate alkoxy radicals can contribute to their nocturnal chemical loss.

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