“Micro to nano : multiscale IR analyses reveal zinc soap heterogeneity in a 19th-century painting by Corot”. Ma X, Pavlidis G, Dillon E, Beltran V, Schwartz JJ, Thoury M, Borondics F, Sandt C, Kjoller K, Berrie BH, Centrone A, Analytical chemistry 94, 3103 (2022). http://doi.org/10.1021/ACS.ANALCHEM.1C04182
Abstract: Formation and aggregation of metal carboxylates (metal soaps) can degrade the appearance and integrity of oil paints, challenging efforts to conserve painted works of art. Endeavors to understand the root cause of metal soap formation have been hampered by the limited spatial resolution of Fourier transform infrared microscopy (mu-FTIR). We overcome this limitation using optical photothermal infrared spectroscopy (O-PTIR) and photothermal-induced resonance (PTIR), two novel methods that provide IR spectra with approximate to 500 and approximate to 10 nm spatial resolutions, respectively. The distribution of chemical phases in thin sections from the top layer of a 19th-century painting is investigated at multiple scales (mu-FTIR approximate to 10(2) mu m(3), O-PTIR approximate to 10(-1) mu m(3), PTIR approximate to 10(-5) mu m(3)). The paint samples analyzed here are found to be mixtures of pigments (cobalt green, lead white), cured oil, and a rich array of intermixed, small (often << 0.1 mu m(3)) zinc soap domains. We identify Zn stearate and Zn oleate crystalline soaps with characteristic narrow IR peaks (approximate to 1530-1558 cm(-1)) and a heterogeneous, disordered, water-permeable, tetrahedral zinc soap phase, with a characteristic broad peak centered at approximate to 1596 cm(-1). We show that the high signal-to-noise ratio and spatial resolution afforded by O-PTIR are ideal for identifying phase-separated (or locally concentrated) species with low average concentration, while PTIR provides an unprecedented nanoscale view of distributions and associations of species in paint. This newly accessible nanocompositional information will advance our knowledge of chemical processes in oil paint and will stimulate new art conservation practices.
Keywords: A1 Journal article; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
DOI: 10.1021/ACS.ANALCHEM.1C04182
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“Correlation between the fluorination degree of perfluorinated zinc phthalocyanines, their singlet oxygen generation ability, and their photoelectrochemical response for phenol sensing”. Neven L, Barich H, Ching HYV, Khan SU, Colomier C, Patel HH, Gorun SM, Verbruggen S, Van Doorslaer S, De Wael K, Analytical chemistry 94, 5221 (2022). http://doi.org/10.1021/ACS.ANALCHEM.1C04357
Abstract: Electron-withdrawing perfluoroalkyl peripheral groups grafted on phthalocyanine (Pc) macrocycles improve their single-site isolation, solubility, and resistance to self-oxidation, all beneficial features for catalytic applications. A high degree of fluorination also enhances the reducibility of Pcs and could alter their singlet oxygen (1O2) photoproduction. The ethanol/toluene 20:80 vol % solvent mixture was found to dissolve perfluorinated FnPcZn complexes, n = 16, 52, and 64, and minimize the aggregation of the sterically unencumbered F16PcZn. The 1O2 production ability of FnPcZn complexes was examined using 9,10-dimethylanthracene (DMA) and 2,2,6,6-tetramethylpiperidine (TEMP) in combination with UV–vis and electron paramagnetic resonance (EPR) spectroscopy, respectively. While the photoreduction of F52PcZn and F64PcZn in the presence of redox-active TEMP lowered 1O2 production, DMA was a suitable 1O2 trap for ranking the complexes. The solution reactivity was complemented by solid-state studies via the construction of photoelectrochemical sensors based on TiO2-supported FnPcZn, FnPcZn|TiO2. Phenol photo-oxidation by 1O2, followed by its electrochemical reduction, defines a redox cycle, the 1O2 production having been found to depend on the value of n and structural features of the supported complexes. Consistent with solution studies, F52PcZn was found to be the most efficient 1O2 generator. The insights on reactivity testing and structural–activity relationships obtained may be useful for designing efficient and robust sensors and for other 1O2-related applications of FnPcZn.
Keywords: A1 Journal article; Organic synthesis (ORSY); Sustainable Energy, Air and Water Technology (DuEL); Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
Impact Factor: 7.4
DOI: 10.1021/ACS.ANALCHEM.1C04357
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“The role of singlet oxygen, superoxide, hydroxide, and hydrogen peroxide in the photoelectrochemical response of phenols at a supported highly fluorinated zinc phthalocyanine”. Neven L, Barich H, Pelmuş, M, Gorun SM, De Wael K, ChemElectroChem 9, e202200108 (2022). http://doi.org/10.1002/CELC.202200108
Abstract: Photoelectrochemical (PEC) sensing of phenolic compounds using singlet oxygen (1O2)-generating photocatalysts has emerged as a powerful detection tool. However, it is currently not known how experimental parameters, such as pH and applied potential, influence the generation of reactive oxygen species (ROS) and their photocurrents. In this article, the PEC response was studied over the 6 to 10 pH range using a rotating (ring) disk (R(R)DE) set-up in combination with quenchers, to identify the ROS formed upon illumination of a supported photosensitizer, F64PcZn. The photocurrents magnitude depended on the applied potential and the pH of the buffer solution. The anodic responses were caused by the oxidation of O2.−, generated due to the quenching of 1O2 with −OH and the reaction of 3O2 with [F64Pc(3-)Zn]. The cathodic responses were assigned to the reduction of 1O2 and O2.−, yielding H2O2. These insights may benefit 1O2 – based PEC sensing applications.
Keywords: A1 Journal article; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
DOI: 10.1002/CELC.202200108
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Van Tendeloo M (2022) Resource-efficient nitrogen removal from sewage : kinetic, physical and chemical tools for mainstream partial nitritation/anammox. iv, 204 p
Abstract: Adequate removal of pollutants from sewage is important to protect the environment and public health. Today, sewage treatment plants are operational in many parts of the world, and although the used technologies are effective in removing pollutants from wastewater, they are energy- and resource-intensive. Reshaping sewage treatment into a two-stage system, with separated organic carbon and nitrogen removal, facilitates the transformation towards energy-positive sewage treatment. This thesis will focus on resource-efficient nitrogen removal from sewage via partial nitritation/anammox (PN/A), with reduced organic carbon and oxygen consumption compared to conventional techniques. PN/A relies on the teamwork between two microbial groups to convert ammonium into nitrogen gas. Several other groups of microbes however can proliferate in the sludge, competing for substrate with the key players, lowering the nitrogen removal efficiency and increasing the energy demand. To obtain the desired microbial community, control tools should be applied to selectively promote the desired microbes while suppressing the unwanted competitors. In this thesis, multiple control tools were studied to establish a workable framework for successful implementation of PN/A in the main stream of a sewage treatment plant. These tools can be divided into three categories: i) kinetic tools, regulating substrate availability (e.g., oxygen availability control and residual ammonium concentration), ii) physical tools, revolving around sludge retention and selection (e.g., sludge age control and sludge aggregation form), and iii) chemical tools, exposing the sludge to stress conditions for which the unwanted microbes are vulnerable (e.g., sludge treatments with a single stressor such as free ammonia). The first research chapter focussed on oxygen availability control and single-stressor sludge treatments. The following two chapters covered the development of a novel multi-stressor concept combining substrate starvation and exposure to sulphide and free ammonia. In the final research chapter, the previously obtained knowledge was combined into a demonstration study on pilot-scale. The combination of these control tools was found effective in achieving nitrogen removal via PN/A, both on lab- and pilot-scale. Consequently, the obtained results in this thesis can catalyse the implementation of mainstream PN/A by providing a toolbox with multiple control tools and clever reactor design, thus advancing the concept of energy neutrality and resource efficiency in sewage treatment plants.
Keywords: Doctoral thesis; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
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“Rapid on-site detection of illicit drugs in smuggled samples with a portable electrochemical device”. Parrilla M, Slosse A, Van Echelpoel R, Montiel FN, Langley AR, Van Durme F, De Wael K, Chemosensors 10, 108 (2022). http://doi.org/10.3390/CHEMOSENSORS10030108
Abstract: The smuggling of illicit drugs urges the development of new tools for rapid on-site identification in cargos. Current methods rely on presumptive color tests and portable spectroscopic techniques. However, these methods sometimes exhibit inaccurate results due to commonly used cutting agents, the colorful nature of the sample or because the drugs are smuggled in common goods. Interestingly, electrochemical sensors can deal with these specific problems. Herein, an electrochemical device is presented that uses affordable screen-printed electrodes for the electrochemical profiling of several illicit drugs by square-wave voltammetry (SWV). The identification of the illicit compound is based on the oxidation potential of the analyte. Hence, a library of electrochemical profiles is built upon the analysis of illicit drugs and common cutting agents. This library allows the design of a tailor-made script that enables the identification of each drug through a user-friendly interface (laptop or mobile phone). Importantly, the electrochemical test is compared by analyzing 48 confiscated samples with other portable devices based on Raman and FTIR spectroscopy as well as a laboratory standard method (i.e., gas chromatography-mass spectrometry). Overall, the electrochemical results, obtained through the analysis of different samples from confiscated cargos at an end-user site, present a promising alternative to current methods, offering low-cost and rapid testing in the field.
Keywords: A1 Journal article; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
DOI: 10.3390/CHEMOSENSORS10030108
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“Real-time electrochemical screening of cocaine in lab and field settings with automatic result generation”. de Jong M, Van Echelpoel R, Langley AR, Eliaerts J, van den Berg J, De Wilde M, Somers N, Samyn N, De Wael K, Drug testing and analysis 14, 1471 (2022). http://doi.org/10.1002/DTA.3276
Abstract: This work presents the results of a novel application for the fast on-site screening of cocaine and its main cutting agents in suspicious and confiscated samples. The methodology behind the novel application consists of portable electrochemical detection coupled with a peak-recognition algorithm for automated result output generation, validated both in laboratory and field settings. Currently used field tests, predominantly colorimetric tests, are lacking accuracy, often giving false positive or negative results. This presses the need for alternative approaches to field testing. By combining portable electrochemical approaches with peak-recognition algorithms, an accuracy of 98.4% concerning the detection of cocaine was achieved on a set of 374 powder samples. In addition, the approach was tested on multiple 'smuggled', colored cocaine powders and cocaine mixtures in solid and liquid states, typically in matrices such as charcoal, syrup and clothing. Despite these attempts to hide cocaine, our approach succeeded in detecting cocaine during on-site screening scenarios. This feature presents an advantage over colorimetric and optical detection techniques, which can fail with colored sample matrices. This enhanced accuracy on smuggled samples will lead to increased efficiency in confiscation procedures in the field, thus significantly reducing societal economic and safety concerns and highlighting the potential for electrochemical approaches in on-the-spot identification of drugs of abuse.
Keywords: A1 Journal article; Pharmacology. Therapy; Engineering sciences. Technology; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
DOI: 10.1002/DTA.3276
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“Optimization of sample preparation for grazing emission X-ray fluorescence in micro- and trace analysis applications”. Claes M, de Bokx P, Willard N, Veny P, Van Grieken R, Spectrochimica acta: part B : atomic spectroscopy 52, 1063 (1997). http://doi.org/10.1016/S0584-8547(96)01654-0
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/S0584-8547(96)01654-0
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“Chemical composition of sediments, suspended matter, river and ground water of the Nile (Aswan-Sohag transvers)”. Dekov VM, Komy Z, Araujo F, van Put A, Van Grieken R, The science of the total environment 201, 195 (1997). http://doi.org/10.1016/S0048-9697(97)84057-0
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/S0048-9697(97)84057-0
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“Use of stable isotope measurements to evaluate the origin of suphur in gypsum layers on limestone buildings”. Torfs KM, Van Grieken RE, Buzek F, Environmental science and technology 31, 2650 (1997)
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Chemical composition of sediments and suspended matter from the Cauvery and Brahmaputra rivers (India)”. Dekov VM, Araujo F, Van Grieken R, Subramanian V, The science of the total environment 203, 51 (1997)
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Indentation of graphene nano-bubbles”. Faraji F, Neek-Amal M, Neyts EC, Peeters FM, Nanoscale 14, 5876 (2022). http://doi.org/10.1039/D2NR01207C
Abstract: Molecular dynamics simulations are used to investigate the effect of an AFM tip when indenting graphene nano bubbles filled by a noble gas (i.e. He, Ne and Ar) up to the breaking point. The failure points resemble those of viral shells as described by the Foppl-von Karman (FvK) dimensionless number defined in the context of elasticity theory of thin shells. At room temperature, He gas inside the bubbles is found to be in the liquid state while Ne and Ar atoms are in the solid state although the pressure inside the nano bubble is below the melting pressure of the bulk. The trapped gases are under higher hydrostatic pressure at low temperatures than at room temperature.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.7
Times cited: 2
DOI: 10.1039/D2NR01207C
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“The role of SnF₂, additive on interface formation in all lead-free FASnI₃, perovskite solar cells”. Zillner J, Boyen H-G, Schulz P, Hanisch J, Gauquelin N, Verbeeck J, Kueffner J, Desta D, Eisele L, Ahlswede E, Powalla M, Advanced functional materials , 2109649 (2022). http://doi.org/10.1002/ADFM.202109649
Abstract: Tin-based perovskites are promising alternative absorber materials for leadfree perovskite solar cells but need strategies to avoid fast tin (Sn) oxidation. Generally, this reaction can be slowed down by the addition of tin fluoride (SnF2) to the perovskite precursor solution, which also improves the perovskite layer morphology. Here, this work analyzes the spatial distribution of the additive within formamidinium tin triiodide (FASnI(3)) films deposited on top of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transporting layers. Employing time-of-flight secondary ion mass spectrometry and a combination of hard and soft X-ray photoelectron spectroscopy, it is found that Sn F2 preferably accumulates at the PEDOT:PSS/perovskite interface, accompanied by the formation of an ultrathin SnS interlayer with an effective thickness of approximate to 1.2 nm.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 19
Times cited: 22
DOI: 10.1002/ADFM.202109649
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“Metal-polymer heterojunction in colloidal-phase plasmonic catalysis”. Rogolino A, Claes N, Cizaurre J, Marauri A, Jumbo-Nogales A, Lawera Z, Kruse J, Sanroman-Iglesias M, Zarketa I, Calvo U, Jimenez-Izal E, Rakovich YP, Bals S, Matxain JM, Grzelczak M, The journal of physical chemistry letters 13, 2264 (2022). http://doi.org/10.1021/ACS.JPCLETT.1C04242
Abstract: Plasmonic catalysis in the colloidal phase requires robust surface ligands that prevent particles from aggregation in adverse chemical environments and allow carrier flow from reagents to nanoparticles. This work describes the use of a water-soluble conjugated polymer comprising a thiophene moiety as a surface ligand for gold nanoparticles to create a hybrid system that, under the action of visible light, drives the conversion of the biorelevant NAD+ to its highly energetic reduced form NADH. A combination of advanced microscopy techniques and numerical simulations revealed that the robust metal-polymer heterojunction, rich in sulfonate functional groups, directs the interaction of electron-donor molecules with the plasmonic photocatalyst. The tight binding of polymer to the gold surface precludes the need for conventional transition-metal surface cocatalysts, which were previously shown to be essential for photocatalytic NAD(+) reduction but are known to hinder the optical properties of plasmonic nanocrystals. Moreover, computational studies indicated that the coating polymer fosters a closer interaction between the sacrificial electron-donor triethanolamine and the nanoparticles, thus enhancing the reactivity.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 5.7
Times cited: 1
DOI: 10.1021/ACS.JPCLETT.1C04242
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“The “Historical Materials BAG&rdquo, : a new facilitated access to synchrotron X-ray diffraction analyses for cultural heritage materials at the European Synchrotron Radiation Facility”. Cotte M, Gonzalez V, Vanmeert F, Monico L, Dejoie C, Burghammer M, Huder L, de Nolf W, Fisher S, Fazlic I, Chauffeton C, Wallez G, Jimenez N, Albert-Tortosa F, Salvado N, Possenti E, Colombo C, Ghirardello M, Comelli D, Avranovich Clerici E, Vivani R, Romani A, Costantino C, Janssens K, Taniguchi Y, McCarthy J, Reichert H, Susini J, Molecules: a journal of synthetic chemistry and natural product chemistry 27, 1997 (2022). http://doi.org/10.3390/MOLECULES27061997
Abstract: The European Synchrotron Radiation Facility (ESRF) has recently commissioned the new Extremely Brilliant Source (EBS). The gain in brightness as well as the continuous development of beamline instruments boosts the beamline performances, in particular in terms of accelerated data acquisition. This has motivated the development of new access modes as an alternative to standard proposals for access to beamtime, in particular via the “block allocation group” (BAG) mode. Here, we present the recently implemented “historical materials BAG”: a community proposal giving to 10 European institutes the opportunity for guaranteed beamtime at two X-ray powder diffraction (XRPD) beamlines-ID13, for 2D high lateral resolution XRPD mapping, and ID22 for high angular resolution XRPD bulk analyses-with a particular focus on applications to cultural heritage. The capabilities offered by these instruments, the specific hardware and software developments to facilitate and speed-up data acquisition and data processing are detailed, and the first results from this new access are illustrated with recent applications to pigments, paintings, ceramics and wood.
Keywords: A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 4.6
DOI: 10.3390/MOLECULES27061997
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“Paraformaldehyde-coated electrochemical sensor for improved on-site detection of amphetamine in street samples”. Schram J, Parrilla M, Slosse A, Van Durme F, Åberg J, Björk K, Bijvoets SM, Sap S, Heerschop MWJ, De Wael K, Microchemical journal 179, 107518 (2022). http://doi.org/10.1016/J.MICROC.2022.107518
Abstract: The increasing illicit production, distribution and abuse of amphetamine (AMP) poses a challenge for law enforcement worldwide. To effectively combat this issue, fast and portable tools for the on-site screening of suspicious samples are required. Electrochemical profile (EP)-based sensing of illicit drugs has proven to be a viable option for this purpose as it allows rapid voltammetric measurements via the use of disposable and low-cost graphite screen-printed electrodes (SPEs). In this work, a highly practical paraformaldehyde (PFA)-coated sensor, which unlocks the detectability of primary amines through derivatization, is developed for the on-site detection of AMP in seized drug samples. A potential interval was defined at the sole AMP peak (which is used for identification of the target analyte) to account for potential shifts due to fluctuations in concentration and temperature, which are relevant factors for on-site use. Importantly, it was found that AMP detection was not hindered by the presence of common diluents and adulterants such as caffeine, even when present in high amounts. When inter-drug differentiation is desired, a simultaneous second test with the same solution on an unmodified electrode is introduced to provide the required additional electrochemical information. Finally, the concept was validated by analyzing 30 seized AMP samples (reaching a sensitivity of 96.7 %) and comparing its performance to that of commercially available Raman and Fourier Transform Infrared (FTIR) devices.
Keywords: A1 Journal article; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
DOI: 10.1016/J.MICROC.2022.107518
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“Ellipticalness index : a simple measure of the complexity of oval leaf shape”. Li Y, Quinn BK, Niinemets Ü, Schrader J, Gielis J, Liu M, Shi P, Pakistan journal of botany : An official publication of pakistan botanical society 54, 1 (2022). http://doi.org/10.30848/PJB2022-6(44)
Abstract: Plants have diverse leaf shapes that have evolved to adapt to the environments they have experienced over their evolutionary history. Leaf shape and leaf size can greatly influence the growth rate, competitive ability, and productivity of plants. However, researchers have long struggled to decide how to properly quantify the complexity of leaf shape. Prior studies recommended the leaf roundness index (RI = 4πA/P2) or dissection index (DI = ), where P is leaf perimeter and A is leaf area. However, these two indices merely measure the extent of the deviation of leaf shape from a circle, which is usually invalid as leaves are seldom circular. In this study, we proposed a simple measure, named the ellipticalness index (EI), for quantifying the complexity of leaf shape based on the hypothesis that the shape of any oval leaf can be regarded as a variation from a standard ellipse. 2220 leaves from nine species of Magnoliaceae were sampled to check the validity of the EI. We also tested the validity of the Montgomery equation (ME), which assumes a proportional relationship between leaf area and the product of leaf length and width, because the EI actually comes from the proportionality coefficient of the ME. We also compared the ME with five other models of leaf area. The ME was found to be the best model for calculating leaf area based on consideration of the trade-off between model fit vs. complexity, which strongly supported the robustness of the EI for describing oval leaf shape. The new index can account for both leaf shape and size, and we conclude that it is a promising method for quantifying and comparing oval leaf shapes across species in future studies.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 1.2
DOI: 10.30848/PJB2022-6(44)
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“Shear banding-activated dynamic recrystallization and phase transformation during quasi-static loading of β-metastable Ti &ndash, 12 wt % Mo alloy”. Choisez L, Ding L, Marteleur M, Kashiwar A, Idrissi H, Jacques PJ, Acta materialia 235, 118088 (2022). http://doi.org/10.1016/J.ACTAMAT.2022.118088
Abstract: Dynamic recrystallization (DRX) within adiabatic shear bands forming during the fracture of TRIP-TWIP β−metastable Ti-12Mo (wt %) alloy was recently reported. The formation of 1-3 µm thick-adiabatic shear bands, and of dynamic recrystallization, was quite surprising as their occurrence generally requires high temperature and/or high strain rate loading while these samples were loaded in quasi-static conditions at room temperature. To better understand the fracture mechanism and associated microstructural evolution, thin foils representative of different stages of the fracture process were machined from the fracture surface by Focused Ion Beam (FIB) and analyzed by Transmission Electron Microscopy (TEM) and Automated Crystal Orientation mapping (ACOM-TEM). Complex microstructure transformations involving severe plastic deformed nano-structuration, crystalline rotation and local precipitation of the omega phase were identified. The spatial and temporal evolution of the microstructure during the propagation of the crack was explained through dynamic recovery and continuous dynamic recrystallization, and linked to the modelled distribution of temperature and strain level where TEM samples were extracted.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 9.4
DOI: 10.1016/J.ACTAMAT.2022.118088
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“Electrochemical methods for on-site multidrug detection at festivals”. Van Echelpoel R, Schram J, Parrilla M, Daems D, Slosse A, Van Durme F, De Wael K, Sensors &, Diagnostics 1, 793 (2022). http://doi.org/10.1039/D2SD00043A
Abstract: Two electrochemical methodologies, i.e. flowchart and dual-sensor, were developed to aid law enforcement present at festivals to obtain a rapid indication of the presence of four illicit drugs in suspicious samples encountered.
Keywords: A1 Journal article; Engineering sciences. Technology; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
DOI: 10.1039/D2SD00043A
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“Microstructural investigation of IASCC crack tips extracted from thimble tube O-ring specimens”. Penders AG, Konstantinovic MJ, Yang T, Bosch R-w, Schryvers D, Somville F, Journal of nuclear materials 565, 153727 (2022). http://doi.org/10.1016/J.JNUCMAT.2022.153727
Abstract: The microstructural features of intergranular irradiation-assisted stress corrosion crack tips from a redeemed neutron-irradiated flux thimble tube (60 dpa) have been investigated using focused-ion beam analysis and (scanning) transmission electron microscopy. The current work presents a close examination of the deformation field and oxide assembly associated with intergranular cracking, in addition to the analysis of radiation-induced segregation at leading grain boundaries. Evidence of stress induced martensitic transformation extending from the crack tips is presented. Intergranular crack arrest is demonstrated on the account of the external tensile stress orientation, and as a consequence of MnS inclusion particles segregating close to the fractured grain boundary. Exclusive observations of grain boundary oxidation prior to the cracking are presented, which is in full-agreement with the internal oxidation model.(c) 2022 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.1
DOI: 10.1016/J.JNUCMAT.2022.153727
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“Tunneling properties in α-T₃, lattices : effects of symmetry-breaking terms”. Cunha SM, da Costa DR, Pereira JM Jr, Costa Filho RN, Van Duppen B, Peeters FM, Physical review B 105, 165402 (2022). http://doi.org/10.1103/PHYSREVB.105.165402
Abstract: The alpha-T3 lattice model interpolates a honeycomb (graphene-like) lattice and a T3 (also known as dice) lattice via the parameter alpha. These lattices are made up of three atoms per unit cell. This gives rise to an additional dispersionless flat band touching the conduction and valence bands. Electrons in this model are analogous to Dirac fermions with an enlarged pseudospin, which provides unusual tunneling features like omnidirectional Klein tunneling, also called super-Klein tunneling (SKT). However, it is unknown how small deviations in the equivalence between the atomic sites, i.e., variations in the alpha parameter, and the number of tunnel barriers changes the transmission properties. Moreover, it is interesting to learn how tunneling occurs through regions where the energy spectrum changes from linear with a middle flat band to a hyperbolic dispersion. In this paper we investigate these properties, its dependence on the number of square barriers and the alpha parameter for either gapped and gapless cases. Furthermore, we compare these results to the case where electrons tunnel from a region with linear dispersion to a region with a bandgap. In the latter case, contrary to tunneling through a potential barrier, the SKT is no longer observed. Finally, we find specific cases where transmission is allowed due to a symmetry breaking of sublattice equivalence.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
DOI: 10.1103/PHYSREVB.105.165402
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“Chemistry, local molybdenum clustering, and electrochemistry in the Li2+xMo1-xO3 solid solutions”. Savina AA, Saiutina VV, Morozov AV, Boev AO, Aksyonov DA, Dejoie C, Batuk M, Bals S, Hadermann J, Abakumov AM, Inorganic chemistry 61, 5637 (2022). http://doi.org/10.1021/ACS.INORGCHEM.2C00420
Abstract: A broad range of cationic nonstoichiometry has been demonstratedfor the Li-rich layered rock-salt-type oxide Li2MoO3, which has generally been considered as a phase with a well-defined chemical composition. Li2+xMo1-xO3(-0.037 <= x <= 0.124) solid solutions were synthesized via hydrogen reduction ofLi2MoO4in the temperature range of 650-1100 degrees C, withxdecreasing with theincrease of the reduction temperature. The solid solutions adopt a monoclinicallydistorted O3-type layered average structure and demonstrate a robust localordering of the Li cations and Mo3triangular clusters within the mixed Li/Mocationic layers. The local structure was scrutinized in detail by electron diffractionand aberration-corrected scanning transmission electron microcopy (STEM),resulting in an ordering model comprising a uniform distribution of the Mo3clusters compatible with local electroneutrality and chemical composition. The geometry of the triangular clusters with their oxygenenvironment (Mo3O13groups) has been directly visualized using differential phase contrast STEM imaging. The established localstructure was used as input for density functional theory (DFT)-based calculations; they support the proposed atomic arrangementand provide a plausible explanation for the staircase galvanostatic charge profiles upon electrochemical Li+extraction fromLi2+xMo1-xO3in Li cells. According to DFT, all electrochemical capacity in Li2+xMo1-xO3solely originates from the cationic Moredox process, which proceeds via oxidation of the Mo3triangular clusters into bent Mo3chains where the electronic capacity of the clusters depends on the initial chemical composition and Mo oxidation state defining the width of the first charge low-voltageplateau. Further oxidation at the high-voltage plateau proceeds through decomposition of the Mo3chains into Mo2dimers and further into individual Mo6+cations
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.6
Times cited: 3
DOI: 10.1021/ACS.INORGCHEM.2C00420
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“Novel optical photothermal infrared (O-PTIR) spectroscopy for the noninvasive characterization of heritage glass-metal objects”. Marchetti A, Beltran V, Nuyts G, Borondics F, De Meyer S, Van Bos M, Jaroszewicz J, Otten E, Debulpaep M, De Wael K, Science Advances 8, eabl6769 (2022). http://doi.org/10.1126/SCIADV.ABL6769
Abstract: Optical photothermal infrared (O-PTIR) is a recently developed molecular spectroscopy technique that allows to noninvasively obtain chemical information on organic and inorganic samples at a submicrometric scale. The high spatial resolution (approximate to 450 nm), lack of sample preparation, and comparability of the spectral results to traditional Fourier transform infrared spectroscopy make it a promising candidate for the analysis of cultural heritage. In this work, the potential of O-PTIR for the noninvasive characterization of small heritage objects (few cubic centimeters) is demonstrated on a series of degraded 16th century brass and glass decorative elements. These small and challenging samples, typically encountering limitations with existing noninvasive methods such as macroscopic x-ray powder diffraction and mu Raman, were successfully characterized by O-PTIR, ultimately identifying the markers of glass-induced metal corrosion processes. The results clearly demonstrate how O-PTIR can be easily implemented in a noninvasive multianalytical strategy for the study of heritage materials, making it a fundamental tool for cultural heritage analyses.
Keywords: A1 Journal article; Engineering sciences. Technology; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab); Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 13.6
DOI: 10.1126/SCIADV.ABL6769
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“How perfluoroalkyl substances modify fluorinated self-assembled monolayer architectures : an electrochemical and computational study”. Moro G, Foumthuim CJD, Spinaci M, Martini E, Cimino D, Balliana E, Lieberzeit P, Romano F, Giacometti A, Campos R, De Wael K, Moretto LM, Analytica chimica acta 1204, 339740 (2022). http://doi.org/10.1016/J.ACA.2022.339740
Abstract: There is an urgent need for sensing strategies to screen perfluoroalkyl substances (PFAS) in aqueous matrices. These strategies must be applicable in large-scale monitoring plans to face the ubiquitous use of PFAS, their wide global spread, and their fast evolution towards short-chain, branched molecules. To this aim, the changes in fluorinated self-assembled monolayers (SAM) with different architectures (pinholes/defects-free and with randomized pinholes/defects) were studied upon exposure to both long and short-chain PFAS. The applicability of fluorinated SAM in PFAS sensing was evaluated. Changes in the SAM structures were characterised combining electrochemical impedance spectroscopy and voltam-metric techniques. The experimental data interpretation was supported by molecular dynamics simu-lations to gain a more in-depth understanding of the interaction mechanisms involved. Pinhole/defect-free fluorinated SAM were found to be applicable to long-chain PFAS screening within switch-on sensing strategy, while a switch-off sensing strategy was reported for screening of both short/long-chain PFAS. These strategies confirmed the possibility to play on fluorophilic interactions when designing PFAS screening methods.(c) 2022 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
DOI: 10.1016/J.ACA.2022.339740
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“Anisotropic and tunable optical conductivity of a two-dimensional semi-Dirac system in the presence of elliptically polarized radiation”. Zhang HY, Xiao YM, N Li Q, Ding L, Van Duppen B, Xu W, Peeters FM, Physical review B 105, 115423 (2022). http://doi.org/10.1103/PHYSREVB.105.115423
Abstract: We investigate the effect of ellipticity ratio of the polarized radiation field on optoelectronic properties of a two-dimensional (2D) semi-Dirac (SD) system. The optical conductivity is calculated within the energy balance equation approach derived from the semiclassical Boltzmann equation. We find that there exists the anisotropic optical absorption induced via both the intra-and interband electronic transition channels in the perpendicular xx and yy directions. Furthermore, we examine the effects of the ellipticity ratio, the temperature, the carrier density, and the band-gap parameter on the optical conductivity of the 2D SD system placed in transverse and vertical directions, respectively. It is shown that the ellipticity ratio, temperature, carrier density, and band-gap parameter can play the important roles in tuning the strength, peak position, and shape of the optical conductivity spectrum. The results obtained from this study indicate that the 2D SD system can be a promising anisotropic and tunable optical and optoelectronic material for applications in innovative 2D optical and optoelectronic devices, which are active in the infrared and terahertz bandwidths.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 3
DOI: 10.1103/PHYSREVB.105.115423
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“Synchrotron XRF analysis identifies cerium accumulation colocalized with pharyngeal deformities in CeO₂, NP-exposed caenorhabditis elegans”. Rossbach LM, Brede DA, Nuyts G, Cagno S, Olsson RMS, Oughton DH, Falkenberg G, Janssens K, Lind OC, Environmental science and technology 56, 5081 (2022). http://doi.org/10.1021/ACS.EST.1C08509
Abstract: A combination of synchrotron radiation-based elementalimaging, in vivo redox status analysis, histology, and toxic responses was usedto investigate the uptake, biodistribution, and adverse effects of Cenanoparticles (CeO2NP; 10 nm; 0.5-34.96 mg Ce L-1) or Ce(NO3)3(2.3-26 mg Ce L-1)inCaenorhabditis elegans. Elemental mapping of theexposed nematodes revealed Ce uptake in the alimentary canal prior todepuration. Retention of CeO2NPs was low compared to that of Ce(NO3)3in depurated individuals. X-rayfluorescence (XRF) mapping showed that Cetranslocation was confined to the pharyngeal valve and foregut. Ce(NO3)3exposure significantly decreased growth, fertility, and reproduction, causedslightly reduced fecundity. XRF mapping and histological analysis revealedsevere tissue deformities colocalized with retained Ce surrounding thepharyngeal valve. Both forms of Ce activated the sod-1 antioxidant defense,particularly in the pharynx, whereas no significant effects on the cellular redox balance were identified. The CeO2NP-induceddeformities did not appear to impair the pharyngeal function or feeding ability as growth effects were restricted to Ce(NO3)3exposure. The results demonstrate the utility of integrated submicron-resolution SR-based XRF elemental mapping of tissue-specificdistribution and adverse effect analysis to obtain robust toxicological evaluations of metal-containing contaminants.
Keywords: A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 11.4
DOI: 10.1021/ACS.EST.1C08509
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“How do western European farms behave and respond to climate change? A simultaneous irrigation-crop decision model”. Vanschoenwinkel J, Vancauteren M, Van Passel S, Climate change economics 13, 2250009 (2022). http://doi.org/10.1142/S2010007822500099
Abstract: Most farm adaptations are reactive actions that run the risk of locking farm systems into suboptimal long-term trajectories. This is especially the case with regard to water management as water scarcity will be aggravated by climate change. This paper looks into farm irrigation choices in combination with crop choices because a proper crop choice has the potential to reduce water requirements. It proposes an extended Ricardian model to capture multiple adaptation decisions explicitly. The new simultaneous irrigation-crop farm decision model uses spatially detailed farm-level data of over 18,000 European farms on irrigation and seven different crop choices. The analysis shows that larger farmers and farmers in less water-scarce regions that use irrigation are more sensitive to temperature increases than rain-fed agriculture. This might be explained by the fact that these farmers do not experience the real cost of water scarcity because of which they take less efficient decisions.
Keywords: A1 Journal article; Economics; Engineering Management (ENM)
DOI: 10.1142/S2010007822500099
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“Isolated and hybrid bilayer graphene quantum rings”. Mirzakhani M, da Costa DR, Peeters FM, Physical review B 105, 115430 (2022). http://doi.org/10.1103/PHYSREVB.105.115430
Abstract: Using the continuum model, we investigate the electronic properties of two types of bilayer graphene (BLG) quantum ring (QR) geometries: (i) An isolated BLG QR and (ii) a monolayer graphene (MLG) with a QR put on top of an infinite graphene sheet (hybrid BLG QR). Solving the Dirac-Weyl equation in the presence of a perpendicular magnetic field and applying the infinite mass boundary condition at the ring boundaries, we obtain analytical results for the energy levels and corresponding wave spinors for both structures. In the case of isolated BLG QR, we observe a sizable and magnetically tunable band gap which agrees with the tight-binding transport simulations. Our analytical results also show the intervalley symmetry EeK (m) = ???EK??? h (m) between the electron (e) and the hole (h) states (m is the angular momentum quantum number) for the energy spectrum of the isolated BLG QR. The presence of interface boundary in a hybrid BLG QR modifies drastically the energy levels as compared with that of an isolated BLG QR. Its energy levels are tunable from MLG dot to isolated BLG QR and to MLG Landau energy levels as the magnetic field is varied. Our predictions can be verified experimentally using different techniques such as by magnetotransport measurements.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 4
DOI: 10.1103/PHYSREVB.105.115430
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“Why does France not meet its pesticide reduction targets? Farmers' socio-economic trade-offs when adopting agro-ecological practices”. Bjørnåvold A, David M, Bohan DA, Gibert C, Rousselle J-M, Van Passel S, Ecological Economics 198, 107440 (2022). http://doi.org/10.1016/J.ECOLECON.2022.107440
Abstract: Despite substantial policy efforts made by the French government to reduce dependence on pesticides, farming practices are only changing slowly. This paper analyses the socio-economic trade-offs that 110 farmers are currently facing in the transition to agro-ecological practices. A mixed-method approach – a quantitative discrete choice experiment (DCE) and qualitative interviews – was set up to understand these farmers' motivations and perspectives, and how policy can improve to accompany them on the road to low chemical input farming. Results of the DCE indicate that the majority of the farmers in our sample are keen to change practices but are at a loss as to how this can be done, as a number of preferences for this transition came out as inconclusive. Qualitative interviews with a representative sample of the farmers that took part in the DCE complemented this result by illustrating a deep uncertainty for the future and a disconnect felt between authorities and themselves as a group. We argue that this uncertainty contributed to a lack of clear-cut solutions established through the DCE. The indepth discussions with farmers illustrated the wish for concrete and local policy measures based on farmers' networks and peer support.
Keywords: A1 Journal article; Economics; Engineering Management (ENM)
Impact Factor: 7
DOI: 10.1016/J.ECOLECON.2022.107440
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“Environmental and economic sustainability of the nitrogen recovery paradigm : evidence from a structured literature review”. Spiller M, Moretti M, De Paepe J, Vlaeminck SE, Resources, conservation and recycling 184, 106406 (2022). http://doi.org/10.1016/J.RESCONREC.2022.106406
Abstract: Our economy drives on reactive nitrogen (Nr); while Nr emissions to the environment surpass the planetary boundary. Increasingly, it is advocated to recover Nr contained in waste streams and to reuse it ‘directly’ in the agri-food chain. Alternatively, Nr in waste streams may be removed as N2 and refixed via the Haber-Bosch process in an ‘indirect’ reuse loop. As a systematic sustainability analysis of ‘direct’ Nr reuse and its comparison to the ‘indirect’ reuse loop is lacking, this structured review aimed to analyze literature determining the environmental and economic sustainability of Nr recovery technologies. Bibliometric records were queried from 2000 to 2020 using Boolean search strings, and manual text coding. In total, 63 studies were selected for the review. Results suggest that ‘direct’ Nr reuse using Nr recovery technologies is the preferred paradigm as the majority of studies concluded that it is sustainable or that it can be sustainable depending on technological assumptions and other scenario variables. Only 17 studies compared the ‘direct’ with the ‘indirect’ Nr reuse route, therefore a system perspective in Nr recovery sustainability assessments should be more widely adopted. Furthermore, Nr reuse should also be analyzed in the context of a ‘new Nr economy’ that relies on decentralized Nr production from renewable energy. It is also recommended that on-par technology readiness level comparisons should be carried out, making use of technology development and technology learning methodologies. Finally, by-products of Nr recovery are important to be accounted for as they are reducing the environmental burdens through avoided impacts.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 13.2
DOI: 10.1016/J.RESCONREC.2022.106406
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“Wearable hollow microneedle sensing patches for the transdermal electrochemical monitoring of glucose”. Parrilla M, Detamornrat U, Domínguez-Robles J, Donnelly RF, De Wael K, Talanta : the international journal of pure and applied analytical chemistry 249, 123695 (2022). http://doi.org/10.1016/J.TALANTA.2022.123695
Abstract: According to the World Health Organization, about 422 million people worldwide have diabetes, with 1.5 million deaths directly attributed each year. Therefore, there is still a need to effectively monitor glucose in diabetic patients for proper management. Recently, wearable patches based on microneedle (MN) sensors provide minimally invasive analysis of glucose through the interstitial fluid (ISF) while exhibiting excellent correlation with blood glucose. Despite many advances in wearable electrochemical sensors, long-term stability and continuous monitoring remain unsolved challenges. Herein, we present a highly stable electrochemical biosensor based on a redox mediator bilayer consisting of Prussian blue and iron-nickel hexacyanoferrate to increase the long-term stability of the readout coupled with a hollow MN array as a sampling unit for ISF uptake. First, the enzymatic biosensor is developed by using affordable screen-printed electrodes (SPE) and optimized for long-term stability fitting the physiological range of glucose in ISF (i.e., 2.5–22.5 mM). In parallel, the MN array is assessed for minimally invasive piercing of the skin. Subsequently, the biosensor is integrated with the MN array leaving a microfluidic spacer that works as the electrochemical cell. Interestingly, a microfluidic channel connects the cell with an external syringe to actively and rapidly withdraw ISF toward the cell. Finally, the robust MN sensing patch is characterized during in vitro and ex vivo tests. Overall, affordable wearable MN-based patches for the continuous monitoring of glucose in ISF are providing an advent in wearable devices for rapid and life-threatening decision-making processes.
Keywords: A1 Journal article; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
DOI: 10.1016/J.TALANTA.2022.123695
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