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| 2. |
- Armand, M., et al.
(author)
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Review-Development of Huckel Type Anions: From Molecular Modeling to Industrial Commercialization. A Success Story
- 2020
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In: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 167:7
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Research review (peer-reviewed)abstract
- This paper reviews the battery electrolyte technologies involving Huckel-type salts as a major electrolyte component. The concept was initially proposed by M. Armand in 1995 and then explored by several research groups. In the present review studies on the optimization of the electrolyte composition starting from molecular modeling through enhancing the yield of the salt synthesis to structural characterization and electrochemical performance are described. Furthermore, the use of the optimized electrolytes in a variety of lithium-ion and post-lithium batteries is presented and discussed. Finally, the commercialization of the up to date technology by Arkema is discussed as well as the performance of the present Huckel anion based electrolytes as compared to other marketed electrolyte technologies.
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| 3. |
- Beale, S. B., et al.
(author)
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Combined two-phase co-flow and counter-flow in a gas channel/porous transport layer assembly
- 2020. - 9
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In: PRiME 2020 : Polymer Electrolyte Fuel Cells and Electrolyzers 20 (PEFC and E 20) - Polymer Electrolyte Fuel Cells and Electrolyzers 20 (PEFC and E 20). - : The Electrochemical Society. - 1938-5862 .- 1938-6737. - 9781607685395 ; 98:9, s. 305-315
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Conference paper (peer-reviewed)abstract
- This paper considers a detailed numerical analysis of combined liquid-gas co-flow in a gas channel, with liquid-gas counter-flow in a porous transport layer, as is typically found on the cathode side of a polymer electrolyte fuel cell. The geometry is obtained by digital reconstruction of nano-computer tomography images. From this, the domain is tessellated with an unstructured castellated or octree mesh, upon which the equations of mass and momentum are solved by means of a volume of fluid method. Liquid water is produced from an electrode where gaseous oxygen is simultaneously consumed by electrochemical reduction; Liquid-gas counter flow in the porous transport layer results in liquid drops being entrained in co-flow in the gas channels and convected by the gas downstream.
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| 4. |
- Schmidt, Florian M., et al.
(author)
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Optical spectroscopy
- 2020. - 2
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In: Breathborne biomarkers and the human volatilome. - : Elsevier. - 9780128199671 - 9780128223970 ; , s. 221-238
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Book chapter (other academic/artistic)abstract
- Optical spectroscopy is widely used for quantitative detection of small molecules in complex gas matrices. Employing a laser as a light source enables highly sensitive, selective, and accurate trace gas analysis in exhaled breath without the need for frequent calibration. Many volatile species with direct physiological relevance, especially small molecules such as CO2, CO, NO, CH4, NH3, HCN, C2H4, and their isotopoloques, can be measured with high time resolution using compact optical analyzers. Thus, laser-based sensors are an important complement to other analytical platforms and contribute to establishing breath gas analysis in the clinical practice. This chapter introduces the basics of optical spectroscopy and describes the most relevant techniques currently used in the field, such as nondispersive, laser absorption, and photoacoustic spectroscopy. Successful applications of optical methods are presented, and the future prospects are discussed. Owing to the advent of novel light sources, such as quantum cascade lasers and optical frequency combs, spectroscopy will continue to play a significant role in breath gas analysis.
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| 5. |
- Prifling, B., et al.
(author)
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Large-Scale Statistical Learning for Mass Transport Prediction in Porous Materials Using 90,000 Artificially Generated Microstructures
- 2021
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In: Frontiers in Materials. - : Frontiers Media SA. - 2296-8016. ; 8
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Journal article (peer-reviewed)abstract
- Effective properties of functional materials crucially depend on their 3D microstructure. In this paper, we investigate quantitative relationships between descriptors of two-phase microstructures, consisting of solid and pores and their mass transport properties. To that end, we generate a vast database comprising 90,000 microstructures drawn from nine different stochastic models, and compute their effective diffusivity and permeability as well as various microstructural descriptors. To the best of our knowledge, this is the largest and most diverse dataset created for studying the influence of 3D microstructure on mass transport. In particular, we establish microstructure-property relationships using analytical prediction formulas, artificial (fully-connected) neural networks, and convolutional neural networks. Again, to the best of our knowledge, this is the first time that these three statistical learning approaches are quantitatively compared on the same dataset. The diversity of the dataset increases the generality of the determined relationships, and its size is vital for robust training of convolutional neural networks. We make the 3D microstructures, their structural descriptors and effective properties, as well as the code used to study the relationships between them available open access.
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| 6. |
- Rosati, Roberto, 1984, et al.
(author)
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Strain-dependent exciton diffusion in transition metal dichalcogenides
- 2021
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In: 2D Materials. - : IOP Publishing. - 2053-1583. ; 8:1
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Journal article (peer-reviewed)abstract
- Monolayers of transition metal dichalcogenides have a remarkable excitonic landscape with deeply bound bright and dark exciton states. Their properties are strongly affected by lattice distortions that can be created in a controlled way via strain. Here, we perform a joint theory-experiment study investigating exciton diffusion in strained tungsten disulfide (WS2) monolayers. We reveal a non-trivial and non-monotonic influence of strain. Lattice deformations give rise to different energy shifts for bright and dark excitons changing the excitonic landscape, the efficiency of intervalley scattering channels and the weight of single exciton species to the overall exciton diffusion. We predict a minimal diffusion coefficient in unstrained WS2 followed by a steep speed-up by a factor of 3 for tensile biaxial strain at about 0.6% strain - in excellent agreement with our experiments. The obtained microscopic insights on the impact of strain on exciton diffusion are applicable to a broad class of multi-valley 2D materials.
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| 7. |
- Bukvic, Olivera, et al.
(author)
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A review on the role of functional limitations on evacuation performance using the International Classification of Functioning, Disability and Health
- 2021
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In: Fire Technology. - : Springer Science and Business Media LLC. - 0015-2684 .- 1572-8099. ; 57:2, s. 507-528
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Research review (peer-reviewed)abstract
- This scoping review addresses the role of functional limitations on evacuation performance of adults in public buildings. Although this topic has been addressed in evacuation research, no linkage is currently available between functional limitations, the predominant activities affected by them and evacuation performance. This review strives to open a debate on the need to classify the impact of disability in terms of functional limitations on evacuation performance according to methods adopted in health science. This paper reviews literature concerning evacuation from public buildings with adults aged ≥ 60 years and/or adults aged ≥ 18 years with functional limitations. The International Classification of Functioning, Disability and Health has been used to identify predominant activities during an evacuation and to perform a structured classification at different levels of resolution to address self-evacuation possibilities. Results of the review are presented in a tabular form linking predominant activities in terms of the International Classification of Functioning, Disability and Health and six categories of functional limitations with the engineering evacuation time-line. The suggested classification can facilitate the assessment of the evacuation-related issues in buildings in relation to the population under consideration. The main research gaps identified include the lack of studies concerning the impact of cognitive limitations on egress, and the need to add the temporal dimension to the methods adopted in accessibility research to allow for their use in the egress field.
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| 8. |
- Thorin, Emil, et al.
(author)
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TDLAS-based photofragmentation spectroscopy for detection of K and KOH in flames under optically thick conditions
- 2020
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In: Optics Letters. - : Optical Society of America. - 0146-9592 .- 1539-4794. ; 45:18, s. 5230-5233
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Journal article (peer-reviewed)abstract
- Photofragmentation spectroscopy is combined with tunable diode laser absorption spectroscopy to measure the line shape of the fragment species. This provides flexibility in choosing the UV pulse location within the line shape and accurate quantification of both target species and background fragment concentrations, even under optically thick conditions. The technique is demonstrated by detection of potassium hydroxide (KOH) and atomic potassium K(g) above solid KOH converted in a premixed methane-air flat flame. Time series of KOH(g) and K(g) concentrations are recorded as a function of solid KOH mass and flame stoichiometry. The total substance released during the conversion is in good agreement with the initial solid KOH mass. Under fuel-rich conditions, increased K(g) concentrations at the expense of KOH(g) are observed compared to thermodynamic equilibrium.
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| 9. |
- Ghorbani, Ramin, 1981-, et al.
(author)
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Impact of breath sampling on exhaled carbon monoxide
- 2020
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In: Journal of Breath Research. - : Institute of Physics Publishing (IOPP). - 1752-7155 .- 1752-7163. ; 14:4
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Journal article (peer-reviewed)abstract
- The influence of breath sampling on exhaled carbon monoxide (eCO) and related pulmonary gas exchange parameters is investigated in a study with 32 healthy non-smokers. Mid-infrared tunable diode laser absorption spectroscopy and well-controlled online sampling is used to precisely measure mouth- and nose-exhaled CO expirograms at exhalation flow rates (EFRs) of 250, 120 and 60 ml s−1, and for 10 s of breath-holding followed by exhalation at 120 ml s−1. A trumpet model with axial diffusion is employed to fit simulated exhalation profiles to the experimental expirograms, which provides equilibrium airway and alveolar CO concentrations and the average lung diffusing capacity in addition to end-tidal concentrations. For all breathing maneuvers, excellent agreement is found between mouth- and nose-exhaled end-tidal CO (ETCO), and the individual values for ETCO and alveolar diffusing capacity are consistent across maneuvers. The eCO parameters clearly show a dependence on EFR, where the lung diffusing capacity increases with EFR, while ETCO slightly decreases. End-tidal CO is largely independent of ambient air CO and alveolar diffusing capacity. While airway CO is slightly higher than, and correlates strongly with, ambient air CO, and there is a weak correlation with ETCO, the results point to negligible endogenous airway CO production in healthy subjects. An EFR of around 120 ml s−1 can be recommended for clinical eCO measurements. The employed method provides means to measure variations in endogenous CO, which can improve the interpretation of exhaled CO concentrations and the diagnostic value of eCO tests in clinical studies.Clinical trial registration number: 2017/306-31
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| 10. |
- Schmidt, H., et al.
(author)
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Gamma and pulsed electron radiolysis studies of CyMe 4 BTBP and CyMe 4 BTPhen: Identification of radiolysis products and effects on the hydrometallurgical separation of trivalent actinides and lanthanides
- 2021
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In: Radiation Physics and Chemistry. - : Elsevier BV. - 1879-0895 .- 0969-806X. ; 189
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Journal article (peer-reviewed)abstract
- The radiolytic stability of the highly selective ligands CyMe4BTBP and CyMe4BTPhen against ionizing gamma radiation was studied in 1-octanol solution. CyMe4BTBP and CyMe4BTPhen are important extractants for a potential treatment of used nuclear fuel. They were studied under identical experimental conditions to directly compare the effects of gamma and pulsed electron radiolysis on the ligands and systematically study the influence of structural changes in the ligand backbone. Distribution ratios of Am3+, Cm3+ and Eu3+, the residual concentration of CyMe4BTBP and CyMe4BTPhen in solution, and the formation of radiolysis products were studied as a function of absorbed gamma dose and presence of an acidic aqueous phase during irradiation. Quantitative and semi-quantitative analyses were used to elucidate the radiolysis mechanism for both ligands. Addition products of alpha-hydroxyoctyl radicals formed through radiolysis of the 1-octanol diluent to the ligand molecules were identified as the predominant radiolysis products. These addition products also extract trivalent metal ions, as distribution ratios remained high although the parent molecule concentrations decreased. Therefore, the utilization time of a solvent using these extractants under the harsh conditions of used nuclear fuel treatment could be considerably longer than expected. Understanding the radiolysis mechanism is crucial for designing more radiation resistant extractants.
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