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“Valorization of flue gas by combining photocatalytic gas pretreatment with microalgae production”. Van Eynde E, Lenaerts B, Tytgat T, Blust R, Lenaerts S, Environmental science and technology 50, 2538 (2016). http://doi.org/10.1021/ACS.EST.5B04824
Abstract: Utilization of flue gas for algae cultivation seems to be a promising route because flue gas from fossil-fuel combustion processes contains the high amounts of carbon (CO2) and nitrogen (NO) that are required for algae growth. NO is a poor nitrogen source for algae cultivation because of its low reactivity and solubility in water and its toxicity for algae at high concentrations. Here, we present a novel strategy to valorize NO from flue gas as feedstock for algae production by combining a photocatalytic gas pretreatment unit with a microalgal photobioreactor. The photocatalytic air pretreatment transforms NO gas into NO2 gas and thereby enhances the absorption of NO in the cultivation broth. The absorbed NOx will form NO2- and NO3- that can be used as a nitrogen source by algae. The effect of photocatalytic air pretreatment on the growth and biomass productivity of the algae Thalassiosira weissflogii in a semicontinuous system aerated with a model flue gas (1% CO2 and 50 ppm of NO) is investigated during a long-term experiment. The integrated system makes it possible to produce algae with NO from flue gas as the sole nitrogen source and reduces the NOx content in the exhaust gas by 84%.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.198
Times cited: 6
DOI: 10.1021/ACS.EST.5B04824
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“The potential of microalgae biorefineries in Belgium and India : an environmental techno-economic assessment”. Thomassen G, Van Dael M, Van Passel S, Bioresource Technology 267, 271 (2018). http://doi.org/10.1016/J.BIORTECH.2018.07.037
Abstract: This study performs an environmental techno-economic assessment (ETEA) for multiple microalgae biorefinery concepts at different locations, those being Belgium and India. The ETEA methodology, which integrates aspects of the TEA and LCA methodologies and provides a clear framework for an integrated assessment model, has been proposed and discussed. The scenario in India has a higher profitability with a NPV of (sic)40 million over a period of 10 years, while the environmental impact in Belgium is lower. The inclusion of a medium recycling step provides the best scenario from both perspectives. The crucial parameters for feasibility are the beta-caroteneprice and content, the upstream environmental impact of electricity and the maximum biomass concentration during cultivation. The identification of these parameters by the ETEA guides future technology developments and shortens the time-to-market for microalgal-based biorefineries.
Keywords: A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM)
Impact Factor: 5.651
Times cited: 8
DOI: 10.1016/J.BIORTECH.2018.07.037
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“Canola adoption enhancement in Western Iran”. Zarafshani K, Ghasemi S, Houshyar E, Ghanbari R, Van Passel S, Azadi H, Journal Of Agricultural Science And Technology 19, 47 (2017)
Abstract: Canola production is an important alternative for agricultural policy-makers in Iran to reduce dependency on the imported vegetable oils. Nevertheless, the canola planted area is only increasing at a slow pace, indicating a low willingness-to-accept of farmers. The general aim of this study was to determine the factors influencing the canola adoption in the Kermanshah Province in Western Iran. Employing stratified random sampling method, 106 farmers from each adopter and non-adopter group were selected. Helping to reach a suitable extensional program, two main categories of variables were defined; i.e. farmers personal characteristics and extension parameters. The analysis of farmers personal characteristics variables revealed that the adopters had larger farms and were younger. The results also show that 80% of the adopters were highly to very highly willing to cultivate canola. Furthermore, a logistic regression model estimated the influence of extensional parameters variables on the canola adoption. According to the regression model, the most effective factors are contact with extension agents and participating in extension classes. As a conclusion, it is suggested that the focus of extension services should be to reduce the distance to agricultural service centers in combination with more contact with extension agents and classes.
Keywords: A1 Journal article; Economics; Engineering Management (ENM)
Impact Factor: 0.813
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“Chemistry reduction of complex CO2chemical kinetics: application to a gliding arc plasma”. Sun SR, Wang HX, Bogaerts A, Plasma Sources Science &, Technology 29, 025012 (2020). http://doi.org/10.1088/1361-6595/ab540f
Abstract: A gliding arc (GA) plasma has great potential for CO2 conversion into value-added chemicals, because of its high energy efficiency. To improve the application, a 2D/3D fluid model is needed to investigate the CO2 conversion mechanisms in the actual discharge geometry. Therefore, the complex CO2 chemical kinetics description must be reduced due to the huge computational cost associated with 2D/3D models. This paper presents a chemistry reduction method for CO2 plasmas, based on the so-called directed relation graph method. Depending on the defined threshold values, some marginal species are identified. By means of a sensitivity analysis, we can further reduce the chemistry set by removing one by one the marginal species. Based on the socalled flux-sensitivity coupling, we obtain a reduced CO2 kinetics model, consisting of 36 or 15 species (depending on whether the 21 asymmetric mode vibrational states of CO2 are explicitly included or lumped into one group), which is applied to a GA discharge. The results are compared with those predicted with the full chemistry set, and very good agreement is reached. Moreover, the range of validity of the reduced CO2 chemistry set is checked, telling us that this reduced set is suitable for low power GA discharges. Finally, the time and spatial evolution of the CO2 plasma characteristics are presented, based on a 2D model with the reduced kinetics.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.8
DOI: 10.1088/1361-6595/ab540f
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“Storage, fertilization and cost properties highlight the potential of dried microbial biomass as organic fertilizer”. Spanoghe J, Grunert O, Wambacq E, Sakarika M, Papini G, Alloul A, Spiller M, Derycke V, Stragier L, Verstraete H, Fauconnier K, Verstraete W, Haesaert G, Vlaeminck SE, Microbial biotechnology , 1 (2020). http://doi.org/10.1111/1751-7915.13554
Abstract: The transition to sustainable agriculture and horticulture is a societal challenge of global importance. Fertilization with a minimum impact on the environment can facilitate this. Organic fertilizers can play an important role, given their typical release pattern and production through resource recovery. Microbial fertilizers (MFs) constitute an emerging class of organic fertilizers and consist of dried microbial biomass, for instance produced on effluents from the food and beverage industry. In this study, three groups of organisms were tested as MFs: a high-rate consortium aerobic bacteria (CAB), the microalga Arthrospira platensis (‘Spirulina’) and a purple non-sulfur bacterium (PNSB) Rhodobacter sp. During storage as dry products, the MFs showed light hygroscopic activity, but the mineral and organic fractions remained stable over a storage period of 91 days. For biological tests, a reference organic fertilizer (ROF) was used as positive control, and a commercial organic growing medium (GM) as substrate. The mineralization patterns without and with plants were similar for all MFs and ROF, with more than 70% of the organic nitrogen mineralized in 77 days. In a first fertilization trial with parsley, all MFs showed equal performance compared to ROF, and the plant fresh weight was even higher with CAB fertilization. CAB was subsequently used in a follow-up trial with petunia and resulted in elevated plant height, comparable chlorophyll content and a higher amount of flowers compared to ROF. Finally, a cost estimation for packed GM with supplemented fertilizer indicated that CAB and a blend of CAB/PNSB (85%/15%) were most cost competitive, with an increase of 6% and 7% in cost compared to ROF. In conclusion, as biobased fertilizers, MFs have the potential to contribute to sustainable plant nutrition, performing as good as a commercially available organic fertilizer, and to a circular economy.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 5.7
DOI: 10.1111/1751-7915.13554
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“Zero-dimensional modeling of unpacked and packed bed dielectric barrier discharges: the role of vibrational kinetics in ammonia synthesis”. van ‘t Veer K, Reniers F, Bogaerts A, Plasma Sources Science &, Technology 29, 045020 (2020). http://doi.org/10.1088/1361-6595/ab7a8a
Abstract: We present a zero-dimensional plasma kinetics model, including both surface and gas phase kinetics, to determine the role of vibrationally excited states in plasma-catalytic ammonia synthesis. We defined a new method to systematically capture the conditions of dielectric barrier discharges (DBDs), including those found in packed bed DBDs. We included the spatial and temporal nature of such discharges by special consideration of the number of micro-discharges in the model. We introduce a parameter that assigns only a part of the plasma power to the microdischarges, to scale the model conditions from filamentary to uniform plasma. Because of the spatial and temporal behaviour of the micro-discharges, not all micro-discharges occurring in the plasma reactor during a certain gas residence time are affecting the molecules. The fraction of power considered in the model ranges from 0.005 %, for filamentary plasma, to 100 %, for uniform plasma. If vibrational excitation is included in the plasma chemistry, these different conditions, however, yield an ammonia density that is only varying within one order of magnitude. At only 0.05 % of the power put into the uniform plasma component, a model neglecting vibrational excitation clearly does not result in adequate amounts of ammonia. Thus, our new model, which accounts for the concept in which not all the power is deposited by the micro-discharges, but some part may also be distributed in between them, suggests that vibrational kinetic processes are really important in (packed bed) DBDs. Indeed, vibrational excitation takes place in both the uniform plasma between the micro-discharges and in the strong micro-discharges, and is responsible for an increased N2 dissociation rate. This is shown here for plasma-catalytic ammonia synthesis, but might also be valid for other gas conversion applications.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.8
DOI: 10.1088/1361-6595/ab7a8a
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“Multi-dimensional modelling of a magnetically stabilized gliding arc plasma in argon and CO2”. Zhang H, Zhang H, Trenchev G, Li X, Wu Y, Bogaerts A, Plasma Sources Science &, Technology 29, 045019 (2020). http://doi.org/10.1088/1361-6595/ab7cbd
Abstract: This study focuses on a magnetically stabilized gliding arc (MGA) plasma. Two fully coupled flow-plasma models (in 3D and 2D) are presented. The 3D model is applied to compare the arc dynamics of the MGA with a traditional gas-driven gliding arc. The 2D model is used for a detailed parametric study on the effect of the external magnetic field. The results show that the relative velocity between the plasma and feed gas is generated due to the Lorentz force, which can increase the plasma-treated gas fraction. The magnetic field also helps to decrease the gas temperature by enhancing heat transfer and to increase the electron number density. This work shows the potential of an external magnetic field to control the gliding arc behavior, for enhanced gas conversion at low gas flow rates.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.8
DOI: 10.1088/1361-6595/ab7cbd
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“Analysis of internal stress build-up during deposition of nanocrystalline Ni thin films using transmission electron microscopy”. Lumbeeck G, Delvaux A, Idrissi H, Proost J, Schryvers D, Thin solid films : an international journal on the science and technology of thin and thick films 707, 138076 (2020). http://doi.org/10.1016/j.tsf.2020.138076
Abstract: Ni thin films sputter-deposited at room temperature with varying Ar pressures were investigated with automated crystal orientation mapping in a transmission electron microscope to uncover the mechanisms controlling the internal stress build-up recorded in-situ during deposition. Large grains were found to induce behaviour similar to a stress-free nucleation layer. The measurements of grain size in most of the Ni thin films are in agreement with the island coalescence model. Low internal stress was observed at low Ar pressure and was explained by the presence of large grains. Relaxation of high internal stress was also noticed at the highest Ar pressure, which was attributed to a decrease of Σ3 twin boundary density due to a low deposition rate. The results provide insightful information to better understand the relationship between structural boundaries and the evolution of internal stress upon deposition of thin films.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
DOI: 10.1016/j.tsf.2020.138076
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“YBa2Cu3O7−xfilms with Ba2Y(Nb,Ta)O6nanoinclusions for high-field applications”. Celentano G, Rizzo F, Augieri A, Mancini A, Pinto V, Rufoloni A, Vannozzi A, MacManus-Driscoll JL, Feighan J, Kursumovic A, Meledin A, Mayer J, Van Tendeloo G, Superconductor Science &, Technology 33, 044010 (2020). http://doi.org/10.1088/1361-6668/ab6ee5
Abstract: The structural and transport properties of YBa2Cu3O7−x films grown by pulsed laser deposition with mixed 2.5 mol% Ba2YTaO6 (BYTO) and 2.5 mol% Ba2YNbO6 (BYNO) double-perovskite secondary phases are investigated in an extended film growth rate, R = 0.02–1.8 nm s−1. The effect of R on the film microstructure analyzed by TEM techniques shows an evolution from sparse and straight to denser, thinner and splayed continuous columns, with mixed BYNO + BYTO (BYNTO) composition, as R increases from 0.02 nm s−1 to 1.2 nm s−1. This microstructure results in very efficient flux pinning at 77 K, leading to a remarkable improvement in the critical current density (J c) behaviour, with the maximum pinning force density F p(Max) = 13.5 GN m−3 and the irreversibility field in excess of 11 T. In this range, the magnetic field values at which the F p is maximized varies from 1 T to 5 T, being related to the BYNTO columnar density. The film deposited when R = 0.3 nm s−1 exhibits the best performances over the whole temperature and magnetic field ranges, achieving F p(Max) = 900 GN m−3 at 10 K and 12 T. At higher rates, R > 1.2 nm s−1, BYNTO columns show a meandering nature and are prone to form short nanorods. In addition, in the YBCO film matrix a more disordered structure with a high density of short stacking faults is observed. From the analysis of the F p(H, T) curves it emerges that in films deposited at the high R limit, the vortex pinning is no longer dominated by BYNTO columnar defects, but by a new mechanism showing the typical temperature scaling law. Even though this microstructure produces a limited improvement at 77 K, it exhibits a strong J c improvement at lower temperature with F p = 700 GN m−3 at 10 K, 12 T and 900 GN m−3 at 4.2 K, 18 T.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.6
DOI: 10.1088/1361-6668/ab6ee5
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“The effect of H2O on the vibrational populations of CO2in a CO2/H2O microwave plasma: a kinetic modelling investigation”. Verheyen C, Silva T, Guerra V, Bogaerts A, Plasma Sources Science &, Technology 29, 095009 (2020). http://doi.org/10.1088/1361-6595/aba1c8
Abstract: Plasma has been studied for several years to convert CO2 into value-added products. If CO2 could be converted in the presence of H2O as a cheap H-source for making syngas and oxygenates, it would mimic natural photosynthesis. However, CO2/H2O plasmas have not yet been extensively studied, not by experiments, and certainly not computationally. Therefore, we present here a kinetic modelling study to obtain a greater understanding of the vibrational kinetics of a CO2/H2O microwave plasma. For this purpose, we first created an electron impact cross section set for H2O, using a swarm-derived method. We added the new cross section set and CO2/H2O-related chemistry to a pure CO2 model. While it was expected that H2O addition mainly causes quenching of the CO2 asymmetric mode vibrational levels due to the additional CO2/H2O vibrational-translational relaxation, our model shows that the modifications in the vibrational kinetics are mainly induced by the strong electron dissociative attachment to H2O molecules, causing a reduction in electron density, and the corresponding changes in the input of energy into the CO2 vibrational levels by electron impact processes.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.8
DOI: 10.1088/1361-6595/aba1c8
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“Strain, electric-field and functionalization induced widely tunable electronic properties in MoS2/BC3, /C3N and / C3N4 van der Waals heterostructures”. Bafekry A, Stampfl C, Ghergherehchi M, Nanotechnology (Bristol. Print) , 295202 pp (2020). http://doi.org/10.1088/1361-6528/AB884E
Abstract: In this paper, the effect of BC3, C3N and C3N4BC(3) and MoS2/C(3)N4 heterostructures are direct semiconductors with band gaps of 0.4 and 1.74 eV, respectively, while MoS2/C3N is a metal. Furthermore, the influence of strain and electric field on the electronic structure of these van der Waals heterostructures is investigated. The MoS2/BC3 heterostructure, for strains larger than -4%, transforms it into a metal where the metallic character is maintained for strains larger than -6%. The band gap decreases with increasing strain to 0.35 eV (at +2%), while for strain (>+6%) a direct-indirect band gap transition is predicted to occur. For the MoS2/C3N heterostructure, the metallic character persists for all strains considered. On applying an electric field, the electronic properties of MoS2/C3N4 are modified and its band gap decreases as the electric field increases. Interestingly, the band gap reaches 30 meV at +0.8 V/angstrom, and with increase above +0.8 V/angstrom, a semiconductor-to-metal transition occurs. Furthermore, we investigated effects of semi- and full-hydrogenation of MoS2/C3N and we found that it leads to a metallic and semiconducting character, respectively.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Times cited: 19
DOI: 10.1088/1361-6528/AB884E
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“Crack initiation in tapered high Si stainless steel specimens : stress threshold analyses”. Penders A, Konstantinovic MJ, Bosch RW, Schryvers D, Corrosion Engineering Science And Technology , 1 (2020). http://doi.org/10.1080/1478422X.2020.1785651
Abstract: Tapered specimens were used for an accelerated test technique to study the crack initiation of high Si stainless steel by means of constant elongation rate tensile testing in a simulated pressurised water reactor environment. Detailed crack density distributions were obtained by applying an advanced crack detection algorithm on iteratively displaced scanning electron microscopy pictures featuring stress corrosion cracks along the specimen's gauge length. By means of finite-element analysis, prominent peaks in the crack density graphs are demonstrated to be related to stress relief and stress build-up during the crack initiation phase. Intrinsic scatter related to the crack detection suggests that stress corrosion cracking is independent of the strain-rate for strain-rates lower than 10(-6 )s(-1). Based on the extrapolation to constant load conditions, the critical threshold value for the duplex high Si stainless steel is estimated to be around 580 MPa.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 1.8
Times cited: 1
DOI: 10.1080/1478422X.2020.1785651
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“Dried aerobic heterotrophic bacteria from treatment of food and beverage effluents: Screening of correlations between operation parameters and microbial protein quality”. Muys M, Papini G, Spiller M, Sakarika M, Schwaiger B, Lesueur C, Vermeir P, Vlaeminck SE, Bioresource Technology 307, 123242 (2020). http://doi.org/10.1016/J.BIORTECH.2020.123242
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 11.4
Times cited: 1
DOI: 10.1016/J.BIORTECH.2020.123242
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“Dunaliella microalgae for nutritional protein : an undervalued asset”. Sui Y, Vlaeminck SE, Trends in biotechnology : regular edition 38, 10 (2020). http://doi.org/10.1016/J.TIBTECH.2019.07.011
Abstract: β-carotene production using Dunaliella microalgae is established, yet their potential as a source of protein for food and feed applications appears to be overlooked. The rich protein content and nutritional tunability of Dunaliella make these algae intriguing sources of sustainable protein. Thus, it is of societal interest to exploit these promising proteinaceous Dunaliella traits.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 17.3
Times cited: 2
DOI: 10.1016/J.TIBTECH.2019.07.011
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“Electronically tunable quantum phase slips in voltage-biased superconducting rings as a base for phase-slip flux qubits”. Kenawy A, Magnus W, Milošević, MV, Sorée B, Superconductor Science &, Technology 33, 125002 (2020). http://doi.org/10.1088/1361-6668/ABB8EB
Abstract: Quantum phase slips represent a coherent mechanism to couple flux states of a superconducting loop. Since their first direct observation, there have been substantial developments in building charge-insensitive quantum phase-slip circuits. At the heart of these devices is a weak link, often a nanowire, interrupting a superconducting loop. Owing to the very small cross-sectional area of such a nanowire, quantum phase slip rates in the gigahertz range can be achieved. Instead, here we present the use of a bias voltage across a superconducting loop to electrostatically induce a weak link, thereby amplifying the rate of quantum phase slips without physically interrupting the loop. Our simulations reveal that the bias voltage modulates the free energy barrier between subsequent flux states in a very controllable fashion, providing a route towards a phase-slip flux qubit with a broadly tunable transition frequency.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.6
Times cited: 4
DOI: 10.1088/1361-6668/ABB8EB
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“Enhancement of pollutants removal from saline wastewater through simultaneous anammox and denitrification (SAD) process with glycine betaine addition”. Zhu W, Li J, Wang B, Chen G, Bioresource Technology 315, 123784 (2020). http://doi.org/10.1016/J.BIORTECH.2020.123784
Abstract: Enhanced pollutants removal from saline wastewater was investigated in simultaneous anammox and denitrification (SAD) process with glycine betaine (GB) addition. Long-term operation indicated the optimal GB dose was around 0.4 mM, which enhanced both anammox and denitrifying activity by 30% and 45%, respectively. The total nitrogen and organic removal rates were 0.38 +/- 0.2 kgN/m(3)/d and 0.34 +/- 0.3 kgCOD/m(3)/d, respectively, which increased by 34.5% and 20.5%. Independent of GB dose, denitrifying activity was promoted, but anammox activity was drastically deteriorated after excessive GB addition. The optimal GB dose predicated by both Gaussian and Modified-Boltzmann models were 0.42-0.45 mM. Besides, the bacterial activity recovery after excessive GB addition could be analyzed by the Modified-Boltzmann model. With 1.5 mM GB, granular floatation occurred since numerous gas bubbles were inside the granules. In general, exogenous GB addition can mitigate salinity inhibition and promote pollutants removal from saline wastewater.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 11.4
Times cited: 1
DOI: 10.1016/J.BIORTECH.2020.123784
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“Mainstream partial nitritation/anammox with integrated fixed-film activated sludge : combined aeration and floc retention time control strategies limit nitrate production”. Seuntjens D, Carvajal Arroyo JM, Van Tendeloo M, Chatzigiannidou I, Molina J, Nop S, Boon N, Vlaeminck SE, Bioresource Technology 314, 123711 (2020). http://doi.org/10.1016/J.BIORTECH.2020.123711
Abstract: Implementation of mainstream partial nitritation/anammox (PN/A) can lead to more sustainable and cost-effective sewage treatment. For mainstream PN/A reactor, an integrated fixed-film activated sludge (IFAS) was operated (26 °C). The effects of floccular aerobic sludge retention time (AerSRT_floc), a novel aeration strategy, and N-loading rate were tested to optimize the operational strategy. The best performance was observed with a low, but sufficient AerSRTfloc (~7d) and continuous aeration with two alternating dissolved oxygen setpoints: 10 min at 0.07–0.13 mg O2 L−1 and 5 min at 0.27–0.43 mg O2 L−1. Nitrogen removal rates were 122 ± 23 mg N L−1 d−1, and removal efficiencies 73 ± 13%. These conditions enabled flocs to act as nitrite sources while the carriers were nitrite sinks, with low abundance of nitrite oxidizing bacteria. The operational strategies in the source-sink framework can serve as a guideline for successful operation of mainstream PN/A reactors.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 11.4
Times cited: 3
DOI: 10.1016/J.BIORTECH.2020.123711
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“Microstructure characterization of oceanic polyethylene debris”. Rowenczyk L, Dazzi A, Deniset-Besseau A, Beltran V, Goudounèche D, Wong-Wah-Chung P, Boyron O, George M, Fabre P, Roux C, Mingotaud AF, ter Halle A, Environmental Science &, Technology 54, 4102 (2020). http://doi.org/10.1021/ACS.EST.9B07061
Abstract: Plastic pollution has become a worldwide concern. It was demonstrated that plastic breaks down to nanoscale particles in the environment, forming so-called nanoplastics. It is important to understand their ecological impact, but their structure is not elucidated. In this original work, we characterize the microstructure of oceanic polyethylene debris and compare it to the nonweathered objects. Cross sections are analyzed by several emergent mapping techniques. We highlight deep modifications of the debris within a layer a few hundred micrometers thick. The most intense modifications are macromolecule oxidation and a considerable decrease in the molecular weight. The adsorption of organic pollutants and trace metals is also confined to this outer layer. Fragmentation of the oxidized layer of the plastic debris is the most likely source of nanoplastics. Consequently the nanoplastic chemical nature differs greatly from plastics.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 11.4
Times cited: 3
DOI: 10.1021/ACS.EST.9B07061
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“Purple non-sulphur bacteria and plant production: benefits for fertilization, stress resistance and the environment”. Sakarika M, Spanoghe J, Sui Y, Wambacq E, Grunert O, Haesaert G, Spiller M, Vlaeminck SE, Microbial biotechnology 13, 1336 (2020). http://doi.org/10.1111/1751-7915.13474
Abstract: Purple non-sulphur bacteria (PNSB) are phototrophic microorganisms, which increasingly gain attention in plant production due to their ability to produce and accumulate high-value compounds that are beneficial for plant growth. Remarkable features of PNSB include the accumulation of polyphosphate, the production of pigments and vitamins and the production of plant growth-promoting substances (PGPSs). Scattered case studies on the application of PNSB for plant cultivation have been reported for decades, yet a comprehensive overview is lacking. This review highlights the potential of using PNSB in plant production, with emphasis on three key performance indicators (KPIs): fertilization, resistance to stress (biotic and abiotic) and environmental benefits. PNSB have the potential to enhance plant growth performance, increase the yield and quality of edible plant biomass, boost the resistance to environmental stresses, bioremediate heavy metals and mitigate greenhouse gas emissions. Here, the mechanisms responsible for these attributes are discussed. A distinction is made between the use of living and dead PNSB cells, where critical interpretation of existing literature revealed the better performance of living cells. Finally, this review presents research gaps that remain yet to be elucidated and proposes a roadmap for future research and implementation paving the way for a more sustainable crop production.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 5.7
Times cited: 10
DOI: 10.1111/1751-7915.13474
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“Purple phototrophic bacteria for resource recovery : challenges and opportunities”. Capson-Tojo G, Batstone DJ, Grassino M, Vlaeminck SE, Puyol D, Verstraete W, Kleerebezem R, Oehmen A, Ghimire A, Pikaar I, Lema JM, Hülsen T, Grassino M, Hulsen T, Biotechnology Advances 43, 107567 (2020). http://doi.org/10.1016/J.BIOTECHADV.2020.107567
Abstract: Sustainable development is driving a rapid focus shift in the wastewater and organic waste treatment sectors, from a “removal and disposal” approach towards the recovery and reuse of water, energy and materials (e.g. carbon or nutrients). Purple phototrophic bacteria (PPB) are receiving increasing attention due to their capability of growing photoheterotrophically under anaerobic conditions. Using light as energy source, PPB can simultaneously assimilate carbon and nutrients at high efficiencies (with biomass yields close to unity (1 g CODbiomass·g CODremoved−1)), facilitating the maximum recovery of these resources as different value-added products. The effective use of infrared light enables selective PPB enrichment in non-sterile conditions, without competition with other phototrophs such as microalgae if ultraviolet-visible wavelengths are filtered. This review reunites results systematically gathered from over 177 scientific articles, aiming at producing generalized conclusions. The most critical aspects of PPB-based production and valorisation processes are addressed, including: (i) the identification of the main challenges and potentials of different growth strategies, (ii) a critical analysis of the production of value-added compounds, (iii) a comparison of the different value-added products, (iv) insights into the general challenges and opportunities and (v) recommendations for future research and development towards practical implementation. To date, most of the work has not been executed under real-life conditions, relevant for full-scale application. With the savings in wastewater discharge due to removal of organics, nitrogen and phosphorus as an important economic driver, priorities must go to using PPB-enriched cultures and real waste matrices. The costs associated with artificial illumination, followed by centrifugal harvesting/dewatering and drying, are estimated to be 1.9, 0.3–2.2 and 0.1–0.3 $·kgdry biomass−1. At present, these costs are likely to exceed revenues. Future research efforts must be carried out outdoors, using sunlight as energy source. The growth of bulk biomass on relatively clean wastewater streams (e.g. from food processing) and its utilization as a protein-rich feed (e.g. to replace fishmeal, 1.5–2.0 $·kg−1) appears as a promising valorisation route.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 16
Times cited: 6
DOI: 10.1016/J.BIOTECHADV.2020.107567
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“Return-sludge treatment with endogenous free nitrous acid limits nitrate production and N₂O emission for mainstream partial nitritation/anammox”. Peng L, Xie Y, Van Beeck W, Zhu W, Van Tendeloo M, Tytgat T, Lebeer S, Vlaeminck SE, Environmental Science &, Technology 54, 5822 (2020). http://doi.org/10.1021/ACS.EST.9B06404
Abstract: Nitrite oxidizing bacteria (NOB) and nitrous oxide (N2O) hinder the development of mainstream partial nitritation/anammox. To overcome these, endogenous free ammonia (FA) and free nitrous acid (FNA), which can be produced in the sidestream, were used for return-sludge treatment for two integrated-film activated sludge reactors containing biomass in flocs and on carriers. The repeated exposure of biomass from one reactor to FA shocks had a limited impact on NOB suppression but inhibited anammox bacteria (AnAOB). In the other reactor, repeated FNA shocks to the separated flocs failed to limit the system’s nitrate production since NOB activity was still high on the biofilms attached to the unexposed carriers. In contrast, the repeated FNA treatment of flocs and carriers favored aerobic ammonium-oxidizing bacteria (AerAOB) over NOB activity with AnAOB negligibly affected. It was further revealed that return-sludge treatment with higher FNA levels led to lower N2O emissions under similar effluent nitrite concentrations. On this basis, weekly 4 h FNA shocks of 2.0 mg of HNO2-N/L were identified as an optimal and realistic treatment, which not only enabled nitrogen removal efficiencies of ∼65% at nitrogen removal rates of ∼130 mg of N/L/d (20 °C) but also yielded the lowest cost and carbon footprint.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 11.4
Times cited: 1
DOI: 10.1021/ACS.EST.9B06404
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“Source/drain materials for Ge nMOS devices: phosphorus activation in epitaxial Si, Ge, Ge1-xSnx and SiyGe1-x-ySnx”. Vohra A, Makkonen I, Pourtois G, Slotte J, Porret C, Rosseel E, Khanam A, Tirrito M, Douhard B, Loo R, Vandervorst W, Ecs Journal Of Solid State Science And Technology 9, 044010 (2020). http://doi.org/10.1149/2162-8777/AB8D91
Abstract: This paper benchmarks various epitaxial growth schemes based on n-type group-IV materials as viable source/drain candidates for Ge nMOS devices. Si:P grown at low temperature on Ge, gives an active carrier concentration as high as 3.5 x 10(20) cm(-3) and a contact resistivity down to 7.5 x 10(-9) Omega.cm(2). However, Si:P growth is highly defective due to large lattice mismatch between Si and Ge. Within the material stacks assessed, one option for Ge nMOS source/drain stressors would be to stack Si:P, deposited at contact level, on top of a selectively grown n-SiyGe1-x-ySnx at source/drain level, in line with the concept of Si passivation of n-Ge surfaces to achieve low contact resistivities as reported in literature (Martens et al. 2011 Appl. Phys. Lett., 98, 013 504). The saturation in active carrier concentration with increasing P (or As)-doping is the major bottleneck in achieving low contact resistivities for as-grown Ge or SiyGe1-x-ySnx. We focus on understanding various dopant deactivation mechanisms in P-doped Ge and Ge1-xSnx alloys. First principles simulation results suggest that P deactivation in Ge and Ge1-xSnx can be explained both by P-clustering and donor-vacancy complexes. Positron annihilation spectroscopy analysis, suggests that dopant deactivation in P-doped Ge and Ge1-xSnx is primarily due to the formation of P-n-V and SnmPn-V clusters. (C) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.2
DOI: 10.1149/2162-8777/AB8D91
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“Unravelling stacking order in epitaxial bilayer MX₂, using 4D-STEM with unsupervised learning”. Mehta AN, Gauquelin N, Nord M, Orekhov A, Bender H, Cerbu D, Verbeeck J, Vandervorst W, Nanotechnology 31, 445702 (2020). http://doi.org/10.1088/1361-6528/ABA5B6
Abstract: Following an extensive investigation of various monolayer transition metal dichalcogenides (MX2), research interest has expanded to include multilayer systems. In bilayer MX2, the stacking order strongly impacts the local band structure as it dictates the local confinement and symmetry. Determination of stacking order in multilayer MX(2)domains usually relies on prior knowledge of in-plane orientations of constituent layers. This is only feasible in case of growth resulting in well-defined triangular domains and not useful in-case of closed layers with hexagonal or irregularly shaped islands. Stacking order can be discerned in the reciprocal space by measuring changes in diffraction peak intensities. Advances in detector technology allow fast acquisition of high-quality four-dimensional datasets which can later be processed to extract useful information such as thickness, orientation, twist and strain. Here, we use 4D scanning transmission electron microscopy combined with multislice diffraction simulations to unravel stacking order in epitaxially grown bilayer MoS2. Machine learning based data segmentation is employed to obtain useful statistics on grain orientation of monolayer and stacking in bilayer MoS2.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.5
Times cited: 13
DOI: 10.1088/1361-6528/ABA5B6
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“Facile dry coating method of high-nickel cathode material by nanostructured fumed alumina (Al2O3) improving the performance of lithium-ion batteries”. Herzog MJ, Gauquelin N, Esken D, Verbeeck J, Janek J, Energy technology 9, 2100028 (2021). http://doi.org/10.1002/ENTE.202100028
Abstract: Surface coating is a crucial method to mitigate the aging problem of high-Ni cathode active materials (CAMs). By avoiding the direct contact of the CAM and the electrolyte, side reactions are hindered. Commonly used techniques like wet or ALD coating are time consuming and costly. Therefore, a more cost-effective coating technique is desirable. Herein, a facile and fast dry powder coating process for CAMs with nanostructured fumed metal oxides are reported. As the model case, the coating of high-Ni NMC (LiNi0.7Mn0.15Co0.15O2) by nanostructured fumed Al2O3 is investigated. A high coverage of the CAM surface with an almost continuous coating layer is achieved, still showing some porosity. Electrochemical evaluation shows a significant increase in capacity retention, cycle life and rate performance of the coated NMC material. The coating layer protects the surface of the CAM successfully and prevents side reactions, resulting in reduced solid electrolyte interface (SEI) formation and charge transfer impedance during cycling. A mechanism on how the coating layer enhances the cycling performance is hypothesized. The stable coating layer effectively prevents crack formation and particle disintegration of the NMC. In depth analysis indicates partial formation of LixAl2O3/LiAlO2 in the coating layer during cycling, enhancing lithium ion diffusivity and thus, also the rate performance.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Times cited: 25
DOI: 10.1002/ENTE.202100028
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“Two-dimensional carbon nitride C₆N nanosheet with egg-comb-like structure and electronic properties of a semimetal”. Bafekry A, Shahrokhi M, Shafique A, Jappor HR, Shojaei F, Feghhi SAH, Ghergherehchi M, Gogova D, Nanotechnology 32, 215702 (2021). http://doi.org/10.1088/1361-6528/ABD50C
Abstract: In this study, the structural, electronic and optical properties of theoretically predicted C6N monolayer structure are investigated by means of Density Functional Theory-based First-Principles Calculations. Phonon band dispersion calculations and molecular dynamics simulations reveal the dynamical and thermal stability of the C6N single-layer structure. We found out that the C6N monolayer has large negative in-plane Poisson's ratios along both X and Y direction and the both values are almost four times that of the famous-pentagraphene. The electronic structure shows that C6N monolayer is a semi-metal and has a Dirac-point in the BZ. The optical analysis using the random phase approximation method constructed over HSE06 illustrates that the first peak of absorption coefficient of the C6N monolayer along all polarizations is located in the IR range of spectrum, while the second absorption peak occurs in the visible range, which suggests its potential applications in optical and electronic devices. Interestingly, optically anisotropic character of this system is highly desirable for the design of polarization-sensitive photodetectors. Thermoelectric properties such as Seebeck coefficient, electrical conductivity, electronic thermal conductivity and power factor are investigated as a function of carrier doping at temperatures 300, 400, and 500 K. In general, we predict that the C6N monolayer could be a new platform for study of novel physical properties in two-dimensional semi-metal materials, which may provide new opportunities to realize high-speed low-dissipation devices.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.44
DOI: 10.1088/1361-6528/ABD50C
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“Thermal instability and volume contraction in a pulsed microwave N2plasma at sub-atmospheric pressure”. Kelly S, van de Steeg A, Hughes A, van Rooij G, Bogaerts A, Plasma Sources Science &, Technology 30, 055005 (2021). http://doi.org/10.1088/1361-6595/abf1d6
Abstract: We studied the evolution of an isolated pulsed plasma in a vortex flow stabilised microwave (MW) discharge in N2 at 25 mbar via the combination of 0D kinetics modelling, iCCD imaging and laser scattering diagnostics. Quenching of electronically excited N2 results in fast gas heating and the onset of a thermal-ionisation instability, contracting the discharge volume. The onset of a thermal-ionisation instability driven by vibrational excitation pathways is found to facilitate significantly higher N2 conversion (i.e. dissociation to atomic N2 ) compared to pre-instability conditions, emphasizing the potential utility of this dynamic in future fixation applications. The instability onset is found to be instigated by super-elastic heating of the electron energy distribution tail via vibrationally excited N2 . Radial contraction of the discharge to the skin depth is found to occur post instability, while the axial elongation is found to be temporarily contracted during the thermal instability onset. An increase in power reflection during the thermal instability onset eventually limits the destabilising effects of exothermic electronically excited N2 quenching. Translational and vibrational temperature reach a quasi-non-equilibrium after the discharge contraction, with translational temperatures reaching ∼1200 K at the pulse end, while vibrational temperatures are found in near equilibrium with the electron energy (1 eV, or ∼11 600 K). This first description of the importance of electronically excited N2 quenching in thermal instabilities gives an additional fundamental understanding of N2 plasma behaviour in pulsed MW context, and thereby brings the eventual implementation of this novel N2 fixation method one step closer.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
DOI: 10.1088/1361-6595/abf1d6
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“TEM investigation of SCC crack tips in high Si stainless steel tapered specimens”. Penders A, Konstantinovic MJ, Van Renterghem W, Bosch RW, Schryvers D, Corrosion Engineering Science And Technology (2021). http://doi.org/10.1080/1478422X.2021.1961665
Abstract: The stress corrosion cracking (SCC) mechanism is investigated in high Si duplex stainless steel in a simulated PWR environment based on TEM analysis of FIB-extracted SCC crack tips. The microstructural investigation in the near vicinity of SCC crack tips illustrates a strain-rate dependence in SCC mechanisms. Detailed analysis of the crack tip morphology, that includes crack tip oxidation and surrounding deformation field, indicates the existence of an interplay between corrosion- and deformation-driven failure as a function of the strain rate. Slow strain-rate crack tips exhibit a narrow cleavage failure which can be linked to the film-induced failure mechanism, while rounded shaped crack tips for faster strain rates could be related to the strain-induced failure. As a result, two nominal strain-rate-dependent failure regimes dominated either by corrosion or deformation-driven cracking mechanisms can be distinguished.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 0.879
DOI: 10.1080/1478422X.2021.1961665
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““Branched&rdquo, structural transformation of the L12-Al3Zr phase manipulated by Cu substitution/segregation in the Al-Cu-Zr alloy system”. Ding L, Zhao M, Ehlers FJH, Jia Z, Zhang Z, Weng Y, Schryvers D, Liu Q, Idrissi H, Journal of materials science &, technology 185, 186 (2024). http://doi.org/10.1016/j.jmst.2023.11.015
Abstract: The effect of Cu on the evolution of the Al3Zr phase in an Al-Cu-Zr cast alloy during solution treatment at 500 °C has been thoroughly studied by combining atomic resolution high-angle annular dark-field scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy and first-principles cal- culations. The heat treatment initially produces a pure L12-Al3Zr microstructure, allowing for about 13 % Cu to be incorporated in the dispersoid. Cu incorporation increases the energy barrier for anti-phase boundary (APB) activation, thus stabilizing the L12 structure. Additional heating leads to a Cu-induced “branched”path for the L12 structural transformation, with the latter process accelerated once the first APB has been created. Cu atoms may either (i) be repelled by the APBs, promoting the transformation to a Cu-poor D023 phase, or (ii) they may segregate at one Al-Zr layer adjacent to the APB, promoting a transformation to a new thermodynamically favored phase, Al4CuZr, formed when these segregation layers are periodically arranged. Theoretical studies suggest that the branching of the L12 transformation path is linked to the speed at which an APB is created, with Cu attraction triggered by a comparatively slow process. This unexpected transformation behavior of the L12-Al3Zr phase opens a new path to understanding, and potentially regulating the Al3Zr dispersoid evolution for high temperature applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 10.9
DOI: 10.1016/j.jmst.2023.11.015
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“Fabry-Perot interferometry with gate-tunable 3D topological insulator nanowires”. Osca J, Moors K, Sorée B, Serra L, Nanotechnology 32, 435002 (2021). http://doi.org/10.1088/1361-6528/AC1633
Abstract: Three-dimensional topological insulator (3D TI) nanowires display remarkable magnetotransport properties that can be attributed to their spin-momentum-locked surface states such as quasiballistic transport and Aharonov-Bohm oscillations. Here, we focus on the transport properties of a 3D TI nanowire with a gated section that forms an electronic Fabry-Perot (FP) interferometer that can be tuned to act as a surface-state filter or energy barrier. By tuning the carrier density and length of the gated section of the wire, the interference pattern can be controlled and the nanowire can become fully transparent for certain topological surface-state input modes while completely filtering out others. We also consider the interplay of FP interference with an external magnetic field, with which Klein tunneling can be induced, and transverse asymmetry of the gated section, e.g. due to a top-gated structure, which displays an interesting analogy with Rashba nanowires. Due to its rich conductance phenomenology, we propose a 3D TI nanowire with gated section as an ideal setup for a detailed transport-based characterization of 3D TI nanowire surface states near the Dirac point, which could be useful towards realizing 3D TI nanowire-based topological superconductivity and Majorana bound states.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.44
DOI: 10.1088/1361-6528/AC1633
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“FLCS-PON : a 100 Gbit/s flexible passive optical network: concepts and field trial”. Borkowski R, Straub M, Ou Y, Lefevre Y, Jelić, ŽL, Lanneer W, Kaneda N, Mahadevan A, Hueckstaedt V, van Veen D, Houtsma V, Coomans W, Bonk R, Maes J, Journal Of Lightwave Technology 39, 5314 (2021). http://doi.org/10.1109/JLT.2021.3102383
Abstract: We demonstrate concepts and results of a field trial for a flexible-rate passive optical network (FLCS-PON), which delivers bitrates up to 100 Gbit/s and allows for adaptations in the transmission method to match the users' channel conditions and optimize throughput. FLCS-PON builds on top of the hardware ecosystem that will be developed for ITU-T 50 Gbit/s PON and employs three new ingredients: optical network unit (ONU) grouping, flexible modulation format, and flexible forward error correction (FEC) code rate. Together, these techniques take advantage of the optical distribution network (ODN) statistics to realize a system capable of more than twofold throughput increase compared to the upcoming 50 Gbit/s PON, but still able to support a full array of deployed fiber edge cases, which are problematic for legacy PONs. In this paper we explain the concepts behind enabling techniques of FLCS-PON. We then report on a field trial over a deployed fiber infrastructure, using a system consisting of one FLCS-PON OLT and two ONUs. We report both pre- and post-forward-error-correction (post-FEC) performance of our system, demonstrating achievable net bitrate over an operator's fiber infrastructure. We realize a downlink transmission at double the speed of ITU-T 50 Gbit/s PON for ONUs exhibiting lower optical path loss (OPL), while simultaneously continue to support ONUs at high OPLs. We additionally realize a record-high 31.5 dB loss budget for 100 Gbit/s transmission using a direct-detection ONU with an optical preamplifier.
Keywords: A1 Journal article; Mass communications; Condensed Matter Theory (CMT)
Impact Factor: 3.671
DOI: 10.1109/JLT.2021.3102383
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