“Dual microfluidic sensor system for enriched electrochemical profiling and identification of illicit drugs on-site”. Steijlen ASM, Parrilla M, Van Echelpoel R, De Wael K, Analytical chemistry 96, 590 (2024). http://doi.org/10.1021/ACS.ANALCHEM.3C05039
Abstract: Electrochemical sensors have emerged as a new analytical tool for illicit drug detection to facilitate ultrafast and accurate identification of suspicious compounds on-site. Drugs of abuse can be identified using their unique voltammetric fingerprint at a given pH. Today, the right buffer solution is manually selected based on drug appearance, and in some cases, a consecutive analysis in two different pH solutions is required. In this work, we present a disposable microfluidic multichannel sensor system that automatically records fingerprints in two pH solutions (e.g., pH 5 and pH 12). This system has two advantages. It will overcome the manual selection of a buffer solution at the right pH, decrease analysis time, and minimize the risk of human errors. Second, the combination of two fingerprints, the superfingerprint, contains more detailed information about the samples, which enhances the selectivity of the analytical technique. First, real-time pH measurements proved that the sample can be brought to the desired pH within a minute. Subsequently, an electrochemical study on the microfluidic platform with 1 mM illicit drug standards of MDMA, cocaine, heroin, and methamphetamine showed that the characteristic voltammetric fingerprints and peak potentials are reproducible, also in the presence of common cutting agents. Finally, the microfluidic concept was validated with real confiscated samples, showing promising results for the user-friendly identification of drugs of abuse. In short, this paper presents a successful proof-of-concept study of a multichannel microfluidic sensor system to enrich the fingerprints of illicit drugs at pH 5 and pH 12, thus providing a low-cost, portable, and rapid identification system of illicit drugs with minimal user intervention.
Keywords: A1 Journal article; Engineering sciences. Technology; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
Impact Factor: 7.4
DOI: 10.1021/ACS.ANALCHEM.3C05039
|
“Engineering green wall botanical biofiltration to abate indoor volatile organic compounds : a review on mechanisms, phyllosphere bioaugmentation, and modeling”. Alvarado-Alvarado AA, Smets W, Irga P, Denys S, Journal of hazardous materials 465, 133491 (2024). http://doi.org/10.1016/J.JHAZMAT.2024.133491
Abstract: Indoor air pollution affects the global population, especially in developed countries where people spend around 90% of their time indoors. The recent pandemic exacerbated the exposure by relying on indoor spaces and a teleworking lifestyle. VOCs are a group of indoor air pollutants with harmful effects on human health at low concentrations. It is widespread that plants can remove indoor VOCs. To this day, research has combined principles of phytoremediation, biofiltration, and bioremediation into a holistic and sustainable technology called botanical biofiltration. Overall, it is sustained that its main advantage is the capacity to break down and biodegrade pollutants using low energy input. This differs from traditional systems that transfer VOCs to another phase. Furthermore, it offers additional benefits like decreased indoor air health costs, enhanced work productivity, and well-being. However, many disparities exist within the field regarding the role of plants, substrate, and phyllosphere bacteria. Yet their role has been theorized; its stability is poorly known for an engineering approach. Previous research has not addressed the bioaugmentation of the phyllosphere to increase the performance, which could boost the system. Moreover, most experiments have studied passive potted plant systems at a lab scale using small chambers, making it difficult to extrapolate findings into tangible parameters to engineer the technology. Active systems are believed to be more efficient yet require more maintenance and knowledge expertise; besides, the impact of the active flow on the long term is not fully understood. Besides, modeling the system has been oversimplified, limiting the understanding and optimization. This review sheds light on the field’s gains and gaps, like concepts, experiments, and modeling. We believe that embracing a multidisciplinary approach encompassing experiments, multiphysics modeling, microbial community analysis, and coworking with the indoor air sector will enable the optimization of the technology and facilitate its adoption.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 13.6
DOI: 10.1016/J.JHAZMAT.2024.133491
|
“Fabrication of larger surface area of ZIF8@ZIF67 reverse core-shell nanostructures for energy storage applications”. Rabani I, Tahir MS, Nisar S, Parrilla M, Truong HB, Kim M, Seo Y-S, Electrochimica acta 475, 143532 (2024). http://doi.org/10.1016/J.ELECTACTA.2023.143532
Abstract: The construction of uniform nanostructure with larger surface area electrodes is a huge challenge for the highvalue added energy storage application. Herein, we demonstrates ZIF67@ZIF8 (core-shell) and ZIF8@ZIF67 (reverse core-shell) nanostructures using a low-cost wet chemical route and used them as supercapacitors. Pristine ZIF-67 and ZIF-8 was used as reference electrodes. Benefiting from the synergistic effect between the ZIF8 and ZIF67, the ZIF8@ZIF67 exhibited the outstanding electrochemical consequences owing to its larger surface area with uniform hexagonal morphology. As optimized ZIF8@ZIF67 nanostructure displayed the highcapacity of 1521 F/g at 1 A/g of current density in a three-electrode assembly in 1 M KOH electrolyte compared with other as-fabricated electrodes. In addition, the ZIF8@ZIF67 nanostructure employed into the symmetric supercapacitors (SSCs) with 1 M KOH electrolyte in two-electrode setup and it exhibited still superior output including capacity (249.8 F/g at 1 A/g), remarkable repeatability (87 % over 10,000 GCD cycles) along with high energy and power density (61.2 Wh/kg & 1260 W/kg). The present study uncovers the relationship between the larger surface area and electrocatalyst performance, supporting an effective approach to prepare favorable materials for enhanced capacity, extended lifespan, and energy density.
Keywords: A1 Journal article; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
Impact Factor: 6.6
DOI: 10.1016/J.ELECTACTA.2023.143532
|
“How flue gas impurities affect the electrochemical reduction of CO₂, to CO and formate”. Van Daele S, Hintjens L, Hoekx S, Bohlen B, Neukermans S, Daems N, Hereijgers J, Breugelmans T, Applied catalysis : B : environmental 341, 123345 (2024). http://doi.org/10.1016/J.APCATB.2023.123345
Abstract: The electrochemical CO2 reduction offers a promising solution to convert waste CO2 into valuable products like CO and formate. However, CO2 capture and purification remains an energy intensive process and therefore the direct usage of industrially available waste CO2 streams containing SO2, NO and O2 impurities becomes more interesting. This work demonstrates an efficient (Faradaic efficiency > 90 %) and stable performance over 20 h with 200 ppm SO2 or NO in the feed gas stream. However, the addition of 1 % O2 to the CO2 feed causes a significant drop in Faradaic efficiency to C-products due to the competitive oxygen reduction reaction. A potential mitigation strategy is to operate at higher total current density to firstly reduce most O2 and achieve sufficient product output from CO2 reduction. These results aid in understanding the impact of flue gas impurities during CO2 electrolysis which is crucial for potentially bypassing the CO2 purification step.
Keywords: A1 Journal article; Engineering sciences. Technology; Applied Electrochemistry & Catalysis (ELCAT); Electron microscopy for materials research (EMAT)
Impact Factor: 22.1
DOI: 10.1016/J.APCATB.2023.123345
|
“In silico study of the impact of oxidation on pyruvate transmission across the hVDAC1 protein channel”. Rezaei M, Ghasemitarei M, Razzokov J, Yusupov M, Ghorbanalilu M, Ejtehadi MR, Archives of biochemistry and biophysics 751, 109835 (2024). http://doi.org/10.1016/J.ABB.2023.109835
Abstract: The overexpression of voltage dependent anion channels (VDACs), particularly VDAC1, in cancer cells compared to normal cells, plays a crucial role in cancer cell metabolism, apoptosis regulation, and energy homeostasis. In this study, we used molecular dynamics (MD) simulations to investigate the effect of a low level of VDAC1 oxidation (induced e.g., by cold atmospheric plasma (CAP)) on the pyruvate (Pyr) uptake by VDAC1. Inhibiting Pyr uptake through VDAC1 can suppress cancer cell proliferation. Our primary target was to study the translocation of Pyr across the native and oxidized forms of hVDAC1, the human VDAC1. Specifically, we employed MD simulations to analyze the hVDAC1 structure by modifying certain cysteine residues to cysteic acids and methionine residues to methionine sulfoxides, which allowed us to investigate the effect of oxidation. Our results showed that the free energy barrier for Pyr translocation through the native and oxidized channel was approximately 4.3 +/- 0.7 kJ mol-1 and 10.8 +/- 1.8 kJ mol-1, respectively. An increase in barrier results in a decrease in rate of Pyr permeation through the oxidized channel. Thus, our results indicate that low levels of CAP oxidation reduce Pyr translocation, resulting in decreased cancer cell proliferation. Therefore, low levels of oxidation are likely sufficient to treat cancer cells given the inhibition of Pyr uptake.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.9
DOI: 10.1016/J.ABB.2023.109835
|
“Influence of pH on urine nitrification : community shifts of ammonia-oxidizing bacteria and inhibition of nitrite-oxidizing bacteria”. Faust V, Vlaeminck SE, Ganigué, R, Udert KM, ACS ES&T engineering 4, 342 (2024). http://doi.org/10.1021/ACSESTENGG.3C00320
Abstract: Urine nitrification is pH-sensitive due to limited alkalinity and high residual ammonium concentrations. This study aimed to investigate how the pH affects nitrogen conversion and the microbial community of urine nitrification with a pH-based feeding strategy. First, kinetic parameters for NH3, HNO2, and NO2– limitation and inhibition were determined for nitrifiers from a urine nitrification reactor. The turning point for ammonia-oxidizing bacteria (AOB), i.e., the substrate concentration at which a further increase would lead to a decrease in activity due to inhibitory effects, was at an NH3 concentration of 12 mg-N L–1, which was reached only at pH values above 7. The total nitrite turning point for nitrite-oxidizing bacteria (NOB) was pH-dependent, e.g., 18 mg-N L–1 at pH 6.3. Second, four years of data from two 120 L reactors were analyzed, showing that stable nitrification with low nitrite was most likely between pH 5.8 and 6.7. And third, six 12 L urine nitrification reactors were operated at total nitrogen concentrations of 1300 and 3600 mg-N L–1 and pH values between 2.5 and 8.5. At pH 6, the AOB Nitrosomonas europaea was found, and the NOB belonged to the genus Nitrobacter. At pH 7, nitrite accumulated, and Nitrosomonas halophila was the dominant AOB. NOB were inhibited by HNO2 accumulation. At pH 8.5, the AOB Nitrosomonas stercoris became dominant, and NH3 inhibited NOB. Without influent, the pH dropped to 2.5 due to the growth of the acid-tolerant AOB “Candidatus Nitrosacidococcus urinae”. In conclusion, pH is a decisive process control parameter for urine nitrification by influencing the selection and kinetics of nitrifiers.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1021/ACSESTENGG.3C00320
|
“Interface thermal conductivities induced by van der Waals interactions”. Dong HM, Liang HP, Tao ZH, Duan YF, Milošević, MV, Chang K, Physical chemistry, chemical physics 26, 4047 (2024). http://doi.org/10.1039/D3CP05377F
Abstract: The interface heat transfer of two layers induced by van der Waals (vdW) contacts is theoretically investigated, based on first-principles calculations at low temperatures. The results suggest that out-of-plane acoustic phonons with low frequencies dominate the interface thermal transport due to the vdW interaction. The interface thermal conductivity is proportional to the cubic of temperature at very low temperatures, but becomes linearly proportional to temperature as temperature increases. We show that manipulating the strain alters vdW coupling, leading to increased interfacial thermal conductivity at the interface. Our findings provide valuable insights into the interface heat transport in vdW heterostructures and support further design and optimization of electronic and optoelectronic nanodevices based on vdW contacts. The heat transfer induced by van der Waals contacts is dominated by ZA phonons. The interface thermal conductivity is proportional to the cubic of temperature, but becomes linearly proportional to temperature as temperature increases.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.3
DOI: 10.1039/D3CP05377F
|
“Low-pressure inductively coupled plasmas in hydrogen : impact of gas heating on the spatial distribution of atomic hydrogen and vibrationally excited states”. Smith GJ, Diomede P, Gibson AR, Doyle SJ, Guerra V, Kushner MJ, Gans T, Dedrick JP, Plasma sources science and technology 33, 025002 (2024). http://doi.org/10.1088/1361-6595/AD1ECE
Abstract: Non-equilibrium inductively coupled plasmas (ICPs) operating in hydrogen are of significant interest for applications including large-area materials processing. Increasing control of spatial gas heating, which drives the formation of neutral species density gradients and the rate of gas-temperature-dependent reactions, is critical. In this study, we use 2D fluid-kinetic simulations with the Hybrid Plasma Equipment Model to investigate the spatially resolved production of atomic hydrogen in a low-pressure planar ICP operating in pure hydrogen (10-20 Pa or 0.075-0.15 Torr, 300 W). The reaction set incorporates self-consistent calculation of the spatially resolved gas temperature and 14 vibrationally excited states. We find that the formation of neutral-gas density gradients, which result from spatially non-uniform electrical power deposition at constant pressure, can drive significant variations in the vibrational distribution function and density of atomic hydrogen when gas heating is spatially resolved. This highlights the significance of spatial gas heating on the production of reactive species in relatively high-power-density plasma processing sources.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.8
DOI: 10.1088/1361-6595/AD1ECE
|
“A multisensor hyperspectral benchmark dataset for unmixing of intimate mixtures”. Koirala B, Rasti B, Bnoulkacem Z, de Lima Ribeiro A, Madriz Y, Herrmann E, Gestels A, De Kerf T, Lorenz S, Fuchs M, Janssens K, Steenackers G, Gloaguen R, Scheunders P, IEEE sensors journal 24, 4694 (2024). http://doi.org/10.1109/JSEN.2023.3343552
Abstract: Optical hyperspectral cameras capture the spectral reflectance of materials. Since many materials behave as heterogeneous intimate mixtures with which each photon interacts differently, the relationship between spectral reflectance and material composition is very complex. Quantitative validation of spectral unmixing algorithms requires high-quality ground truth fractional abundance data, which are very difficult to obtain. In this work, we generated a comprehensive laboratory ground truth dataset of intimately mixed mineral powders. For this, five clay powders (Kaolin, Roof clay, Red clay, mixed clay, and Calcium hydroxide) were mixed homogeneously to prepare 325 samples of 60 binary, 150 ternary, 100 quaternary, and 15 quinary mixtures. Thirteen different hyperspectral sensors have been used to acquire the reflectance spectra of these mixtures in the visible, near, short, mid, and long-wavelength infrared regions (350-15385) nm. Overlaps in wavelength regions due to the operational ranges of each sensor and variations in acquisition conditions resulted in a large amount of spectral variability. Ground truth composition is given by construction, but to verify that the generated samples are sufficiently homogeneous, XRD and XRF elemental analysis is performed. We believe these data will be beneficial for validating advanced methods for nonlinear unmixing and material composition estimation, including studying spectral variability and training supervised unmixing approaches. The datasets can be downloaded from the following link: https://github.com/VisionlabHyperspectral/Multisensor_datasets.
Keywords: A1 Journal article; Engineering sciences. Technology; Vision lab; Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 4.3
DOI: 10.1109/JSEN.2023.3343552
|
“New indices to balance α-diversity against tree size inequality”. Zhang L, Quinn BK, Hui C, Lian M, Gielis J, Gao J, Shi P, Journal of forestry research 35, 31 (2024). http://doi.org/10.1007/S11676-023-01686-3
Abstract: The number and composition of species in a community can be quantified with alpha-diversity indices, including species richness (R), Simpson's index (D), and the Shannon-Wiener index (HGREEK TONOS). In forest communities, there are large variations in tree size among species and individuals of the same species, which result in differences in ecological processes and ecosystem functions. However, tree size inequality (TSI) has been largely neglected in studies using the available diversity indices. The TSI in the diameter at breast height (DBH) data for each of 999 20 m x 20 m forest census quadrats was quantified using the Gini index (GI), a measure of the inequality of size distribution. The generalized performance equation was used to describe the rotated and right-shifted Lorenz curve of the cumulative proportion of DBH and the cumulative proportion of number of trees per quadrat. We also examined the relationships of alpha-diversity indices with the GI using correlation tests. The generalized performance equation effectively described the rotated and right-shifted Lorenz curve of DBH distributions, with most root-mean-square errors (990 out of 999 quadrats) being < 0.0030. There were significant positive correlations between each of three alpha-diversity indices (i.e., R, D, and H') and the GI. Nevertheless, the total abundance of trees in each quadrat did not significantly influence the GI. This means that the TSI increased with increasing species diversity. Thus, two new indices are proposed that can balance alpha-diversity against the extent of TSI in the community: (1 – GI) x D, and (1 – GI) x H'. These new indices were significantly correlated with the original D and HGREEK TONOS, and did not increase the extent of variation within each group of indices. This study presents a useful tool for quantifying both species diversity and the variation in tree sizes in forest communities, especially in the face of cumulative species loss under global climate change.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3
DOI: 10.1007/S11676-023-01686-3
|
“On central focusing for contrast optimization in direct electron ptychography of thick samples”. Gao C, Hofer C, Pennycook TJ, Ultramicroscopy 256, 113879 (2024). http://doi.org/10.1016/J.ULTRAMIC.2023.113879
Abstract: Ptychography provides high dose efficiency images that can reveal light elements next to heavy atoms. However, despite ptychography having an otherwise single signed contrast transfer function, contrast reversals can occur when the projected potential becomes strong for both direct and iterative inversion ptychography methods. It has recently been shown that these reversals can often be counteracted in direct ptychography methods by adapting the focus. Here we provide an explanation of why the best contrast is often found with the probe focused to the middle of the sample. The phase contribution due to defocus at each sample slice above and below the central plane in this configuration effectively cancels out, which can prevent contrast reversals when dynamical scattering effects are not overly strong. In addition we show that the convergence angle can be an important consideration for removal of contrast reversals in relatively thin samples.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.2
DOI: 10.1016/J.ULTRAMIC.2023.113879
|
“On the coupling of magnetic moments to superconducting quantum interference devices”. Linek J, Wyszynski M, Müller B, Korinski D, Milošević, MV, Kleiner R, Koelle D, Superconductor science and technology 37, 025010 (2024). http://doi.org/10.1088/1361-6668/AD1AE9
Abstract: We investigate the coupling factor phi( mu) that quantifies the magnetic flux phi per magnetic moment mu of a point-like magnetic dipole that couples to a superconducting quantum interference device (SQUID). Representing the dipole by a tiny current-carrying (Amperian) loop, the reciprocity of mutual inductances of SQUID and Amperian loop provides an elegant way of calculating phi(mu)(r,e(mu)) vs. position r and orientation e(mu) of the dipole anywhere in space from the magnetic field B-J(r) produced by a supercurrent circulating in the SQUID loop. We use numerical simulations based on London and Ginzburg-Landau theory to calculate phi (mu) from the supercurrent density distributions in various superconducting loop geometries. We treat the far-field regime ( r greater than or similar to a= inner size of the SQUID loop) with the dipole placed on (oriented along) the symmetry axis of circular or square shaped loops. We compare expressions for phi (mu) from simple filamentary loop models with simulation results for loops with finite width w (outer size A > alpha), thickness d and London penetration depth lambda(L )and show that for thin ( d << alpha ) and narrow (w < alpha) loops the introduction of an effective loop size a(eff) in the filamentary loop-model expressions results in good agreement with simulations. For a dipole placed right in the center of the loop, simulations provide an expression phi(mu)(a,A,d,lambda(L)) that covers a wide parameter range. In the near-field regime (dipole centered at small distance z above one SQUID arm) only coupling to a single strip representing the SQUID arm has to be considered. For this case, we compare simulations with an analytical expression derived for a homogeneous current density distribution, which yields excellent agreement for lambda(L)>w,d . Moreover, we analyze the improvement of phi(mu) provided by the introduction of a narrow constriction in the SQUID arm below the magnetic dipole.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.6
DOI: 10.1088/1361-6668/AD1AE9
|
“On the role of microstructural defects on precipitation, damage, and healing behavior in a novel Al-0.5Mg2Si alloy”. Kashiwar A, Arseenko M, Simar A, Idrissi H, Materials &, design 239, 112765 (2024). http://doi.org/10.1016/J.MATDES.2024.112765
Abstract: A recently developed healable Al-Mg2Si designed by the programmed damage and repair (PDR) strategy is studied considering the role microstructural defects play on precipitation, damage, and healing. The alloy incorporates sacrificial Mg2Si particles that precipitate after friction stir processing (FSP). They act as damage localization sites and are healable based on the solid-state diffusion of Al-matrix. A combination of different transmission electron microscopy (TEM) imaging techniques enabled the visualization and quantification of various crystallographic defects and the spatial distribution of Mg2Si precipitates. Intragrain nucleation is found to be the dominant mechanism for precipitation during FSP whereas grain boundaries and subgrain boundaries mainly lead to coarsening of the precipitates. The statistical and spatial analyses of the damaged particles have shown particle fracture as the dominant damage mechanism which is strongly dependent on the size and aspect ratio of the particles whereas the damage was not found to depend on the location of the precipitates within the matrix. The damaged particles are associated with dislocations accumulated around them. The interplay of these dislocations is directly visualized during healing based on in situ TEM heating which revealed recovery in the matrix as an operative mechanism during the diffusion healing of the PDR alloy.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 8.4
DOI: 10.1016/J.MATDES.2024.112765
|
“Plasmonic photocatalytic coatings with self-cleaning, antibacterial, air and water purifying properties tested according to ISO standards”. Peeters H, Raes A, Verbruggen SW, Journal of photochemistry and photobiology: A: chemistry 451, 115529 (2024). http://doi.org/10.1016/J.JPHOTOCHEM.2024.115529
Abstract: ISO 10678:2010, ISO 22197–1 and 2, ISO 27447:2019 and ISO 27448:2009 for the photocatalytic degradation of organic dyes (methylene blue), air pollution (NOx and acetaldehyde), bacteria (E. coli and S. aureus) and solid organic fouling (oleic acid) are performed on plasmon-embedded TiO2 thin films on Borofloat® glass, as well as the commercially available titania-based self-cleaning glass PilkingtonActivTM. These standardised protocols measure the performance for the four main applications of photocatalytic materials: water purification, air purification, antibacterial and self-cleaning activity, respectively. The standards are performed exactly as prescribed to measure the activity under UV irradiation, and also in a slightly adapted manner to measure the performance under simulated solar light or visible light. Performing experiments according to ISO standards, enables an objective comparison amongst samples tested here, as well as with results from literature. This is a major asset compared to the myriad of customised setups used in laboratories worldwide that hinder a fair comparison. We point at the importance of meticulously following the ISO instructions, as we have noticed that multiple published studies adopting the ISO standards too often deviate from these protocols, thereby nullifying the added value of standardized testing. Following the ISO tests to the letter, we have demonstrated the superior performance of a previously developed plasmonic titania coating with fully embedded gold-silver nanoparticles towards all four application areas. Furthermore, our empirical data strongly support the need for a nuanced understanding of standardized testing, to ensure accurate assessment of photocatalytic materials. An examination of the ISO standards used in this work reveals notable drawbacks, including concerns about the reliability of the methylene blue degradation protocol, the issues of HNO3 accumulation in the NOx removal test, and limitations in assessing antibacterial activity and water contact angles.
Keywords: A1 Journal article; Engineering sciences. Technology
Impact Factor: 4.3
DOI: 10.1016/J.JPHOTOCHEM.2024.115529
|
“Recent progress in developing non-noble metal-based photocathodes for solar green hydrogen production”. Minja AC, Ag KR, Raes A, Borah R, Verbruggen SW, Current Opinion in Chemical Engineering 43, 101000 (2024). http://doi.org/10.1016/J.COCHE.2024.101000
Abstract: Photocathodes play a vital role in photoelectrocatalytic water splitting by acting as catalysts for reducing protons to hydrogen gas when exposed to light. Recent advancements in photocathodes have focused on addressing the limitations of noble metal-based materials. These noble metal-based photocathodes rely on expensive and scarce metals such as platinum and gold as cocatalysts or ohmic back contacts, respectively, rendering the final system less sustainable and costly when applied at scale. This mini-review summarizes the important recent progress in the development of non-noble metal-based photocathodes and their performance in the hydrogen evolution reaction during photoelectrochemical (PEC) water splitting. These advancements bring non-noble metal-based photocathodes closer to their noble metal-based counterparts in terms of performance, thereby paving the way forward toward industrial-scale photoelectrolyzers or PEC cells for green hydrogen production.
Keywords: A1 Journal article; Engineering sciences. Technology
Impact Factor: 6.6
DOI: 10.1016/J.COCHE.2024.101000
|
“Recurrent multi-stressor floc treatments with sulphide and free ammonia enabled mainstream partial nitritation/anammox”. Van Tendeloo M, Baptista MC, Van Winckel T, Vlaeminck SE, The science of the total environment 912, 169449 (2024). http://doi.org/10.1016/J.SCITOTENV.2023.169449
Abstract: Selective suppression of nitrite-oxidising bacteria (NOB) over aerobic and anoxic ammonium-oxidising bacteria (AerAOB and AnAOB) remains a major challenge for mainstream partial nitritation/anammox implementation, a resource-efficient nitrogen removal pathway. A unique multi-stressor floc treatment was therefore designed and validated for the first time under lab-scale conditions while staying true to full-scale design principles. Two hybrid (suspended + biofilm growth) reactors were operated continuously at 20.2 ± 0.6 °C. Recurrent multi-stressor floc treatments were applied, consisting of a sulphide-spiked deoxygenated starvation followed by a free ammonia shock. A good microbial activity balance with high AnAOB (71 ± 21 mg N L−1 d−1) and low NOB (4 ± 17 % of AerAOB) activity was achieved by combining multiple operational strategies: recurrent multi-stressor floc treatments, hybrid sludge (flocs & biofilm), short floc age control, intermittent aeration, and residual ammonium control. The multi-stressor treatment was shown to be the most important control tool and should be continuously applied to maintain this balance. Excessive NOB growth on the biofilm was avoided despite only treating the flocs to safeguard the AnAOB activity on the biofilm. Additionally, no signs of NOB adaptation were observed over 142 days. Elevated effluent ammonium concentrations (25 ± 6 mg N L−1) limited the TN removal efficiency to 39 ± 9 %, complicating a future full-scale implementation. Operating at higher sludge concentrations or reducing the volumetric loading rate could overcome this issue. The obtained results ease the implementation of mainstream PN/A by providing and additional control tool to steer the microbial activity with the multi-stressor treatment, thus advancing the concept of energy neutrality in sewage treatment plants.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.8
DOI: 10.1016/J.SCITOTENV.2023.169449
|
“Rhodotorula kratochvilovae outperforms Cutaneotrichosporon oleaginosum in the valorisation of lignocellulosic wastewater to microbial oil”. Broos W, Wittner N, Dries J, Vlaeminck SE, Gunde-Cimerman N, Cornet I, Process biochemistry (1991) 137, 229 (2024). http://doi.org/10.1016/J.PROCBIO.2024.01.009
Abstract: Rhodotorula kratochvilovae has shown to be a promising species for microbial oil production from lignin-derived compounds. Yet, information on R. kratochvilovae’s detoxification and microbial oil production is scarce. This study investigated the growth and microbial oil production on the phenolic-containing effluent from poplar steam explosion and its detoxification with five R. kratochvilovae strains (EXF11626, EXF9590, EXF7516, EXF3697, EXF3471) and compared them with Cutaneotrichosporon oleaginosum. The R. kratochvilovae strains reached a maximum growth rate up to four times higher than C. oleaginosum. Furthermore, all R. kratochvilovae strains generally degraded phenolics more rapidly and to a larger extent than C. oleaginosum. However, the diluted substrate limited the lipid production by all strains as the maximum lipid content and titre were 10.5% CDW and 0.40 g/L, respectively. Therefore, future work should focus on increasing lipid production by using advanced fermentation strategies and stimulating the enzyme excretion by the yeasts for complex substrate breakdown.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Biochemical Wastewater Valorization & Engineering (BioWaVE)
Impact Factor: 4.4
DOI: 10.1016/J.PROCBIO.2024.01.009
|
“Superconductor-semiconductor hybrid capacitance with a nonlinear charge-voltage profile”. Lauwens J, Kerkhofs L, Sala A, Sorée B, Journal of physics: D: applied physics 57, 025301 (2024). http://doi.org/10.1088/1361-6463/ACFE87
Abstract: Electronic devices that work in the quantum regime often employ hybrid nanostructures to bring about a nonlinear behaviour. The nonlinearity that these can provide has proven to be useful, in particular, for applications in quantum computation. Here we present a hybrid device that acts as a capacitor with a nonlinear charge-voltage relation. The device consists of a nanowire placed between the plates of a coplanar capacitor, with a co-parallel alignment. At low temperatures, due to the finite density of states on the nanowire, the charge distribution in the capacitor is uneven and energy-dependent, resulting in a charge-dependent effective capacitance. We study this system analytically and numerically, and show that the nonlinearity of the capacitance is significant enough to be utilized in circuit quantum electrodynamics. The resulting nonlinearity can be switched on, modulated, and switched off by an external potential, thus making this capacitive device highly versatile for uses in quantum computation.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.4
DOI: 10.1088/1361-6463/ACFE87
|
“Towards fully electrically controlled domain-wall logic”. Vermeulen BB, Raymenants E, Pham VT, Pizzini S, Sorée B, Wostyn K, Couet S, Nguyen VD, Temst K, AIP advances 14, 025030 (2024). http://doi.org/10.1063/9.0000811
Abstract: Utilizing magnetic tunnel junctions (MTJs) for write/read and fast spin-orbit-torque (SOT)-driven domain-wall (DW) motion for propagation, enables non-volatile logic and majority operations, representing a breakthrough in the implementation of nanoscale DW logic devices. Recently, current-driven DW logic gates have been demonstrated via magnetic imaging, where the Dzyaloshinskii-Moriya interaction (DMI) induces chiral coupling between perpendicular magnetic anisotropy (PMA) regions via an in-plane (IP) oriented region. However, full electrical operation of nanoscale DW logic requires electrical write/read operations and a method to pattern PMA and IP regions compatible with the fabrication of PMA MTJs. Here, we study the use of a Hybrid Free Layer (HFL) concept to combine an MTJ stack with DW motion materials, and He+ ion irradiation to convert the stack from PMA to IP. First, we investigate the free layer thickness dependence of 100-nm diameter HFL-MTJ devices and find an optimal CoFeB thickness, from 7 to 10 angstrom, providing high tunneling magnetoresistance (TMR) readout and efficient spin-transfer torque (STT) writing. We then show that high DMI materials, like Pt/Co, can be integrated into an MTJ stack via interlayer exchange coupling with the CoFeB free layer. In this design, DMI values suitable for SOT-driven DW motion are measured by asymmetric bubble expansion. Finally, we demonstrate that He+ irradiation reliably converts the coupled free layers from PMA to IP. These findings offer a path toward the integration of fully electrically controlled DW logic circuits.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
DOI: 10.1063/9.0000811
|
“Voltammetric drug testing makes sense at the border”. Van Echelpoel R, De Wael K, Nature Reviews Chemistry , 1 (2024). http://doi.org/10.1038/S41570-023-00571-1
Abstract: The European BorderSens project leverages voltammetric sensors, developed with end-users' input, to rapidly and accurately detect illicit drugs. By embracing practicalities and validation, this technology has the potential to combat the illicit drug problem.
Keywords: A1 Journal article; Engineering sciences. Technology; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
DOI: 10.1038/S41570-023-00571-1
|
“Whole transcriptome analysis highlights nutrient limitation of nitrogen cycle bacteria in simulated microgravity”. Verbeelen T, Fernandez CA, Nguyen TH, Gupta S, Aarts R, Tabury K, Leroy B, Wattiez R, Vlaeminck SE, Leys N, Ganigué, R, Mastroleo F, NPJ microgravity 10, 3 (2024). http://doi.org/10.1038/S41526-024-00345-Z
Abstract: Regenerative life support systems (RLSS) will play a vital role in achieving self-sufficiency during long-distance space travel. Urine conversion into a liquid nitrate-based fertilizer is a key process in most RLSS. This study describes the effects of simulated microgravity (SMG) on Comamonas testosteroni, Nitrosomonas europaea, Nitrobacter winogradskyi and a tripartite culture of the three, in the context of nitrogen recovery for the Micro-Ecological Life Support System Alternative (MELiSSA). Rotary cell culture systems (RCCS) and random positioning machines (RPM) were used as SMG analogues. The transcriptional responses of the cultures were elucidated. For CO2-producing C. testosteroni and the tripartite culture, a PermaLifeTM PL-70 cell culture bag mounted on an in-house 3D-printed holder was applied to eliminate air bubble formation during SMG cultivation. Gene expression changes indicated that the fluid dynamics in SMG caused nutrient and O2 limitation. Genes involved in urea hydrolysis and nitrification were minimally affected, while denitrification-related gene expression was increased. The findings highlight potential challenges for nitrogen recovery in space.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1038/S41526-024-00345-Z
|
“Improving stability of CO₂, electroreduction by incorporating Ag NPs in N-doped ordered mesoporous carbon structures”. Van den Hoek J, Daems N, Arnouts S, Hoekx S, Bals S, Breugelmans T, ACS applied materials and interfaces 16, 6931 (2024). http://doi.org/10.1021/ACSAMI.3C12261
Abstract: The electroreduction of carbon dioxide (eCO2RR) to CO using Ag nanoparticles as an electrocatalyst is promising as an industrial carbon capture and utilization (CCU) technique to mitigate CO2 emissions. Nevertheless, the long-term stability of these Ag nanoparticles has been insufficient despite initial high Faradaic efficiencies and/or partial current densities. To improve the stability, we evaluated an up-scalable and easily tunable synthesis route to deposit low-weight percentages of Ag nanoparticles (NPs) on and into the framework of a nitrogen-doped ordered mesoporous carbon (NOMC) structure. By exploiting this so-called nanoparticle confinement strategy, the nanoparticle mobility under operation is strongly reduced. As a result, particle detachment and agglomeration, two of the most pronounced electrocatalytic degradation mechanisms, are (partially) blocked and catalyst durability is improved. Several synthesis parameters, such as the anchoring agent, the weight percentage of Ag NPs, and the type of carbonaceous support material, were modified in a controlled manner to evaluate their respective impact on the overall electrochemical performance, with a strong emphasis on operational stability. The resulting powders were evaluated through electrochemical and physicochemical characterization methods, including X-ray diffraction (XRD), N2-physisorption, Inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM), SEM-energy-dispersive X-ray spectroscopy (SEM-EDS), high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), STEM-EDS, electron tomography, and X-ray photoelectron spectroscopy (XPS). The optimized Ag/soft-NOMC catalysts showed both a promising selectivity (∼80%) and stability compared with commercial Ag NPs while decreasing the loading of the transition metal by more than 50%. The stability of both the 5 and 10 wt % Ag/soft-NOMC catalysts showed considerable improvements by anchoring the Ag NPs on and into a NOMC framework, resulting in a 267% improvement in CO selectivity after 72 h (despite initial losses) compared to commercial Ag NPs. These results demonstrate the promising strategy of anchoring Ag NPs to improve the CO selectivity during prolonged experiments due to the reduced mobility of the Ag NPs and thus enhanced stability.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 9.5
DOI: 10.1021/ACSAMI.3C12261
|
“Deep convolutional neural networks to restore single-shot electron microscopy images”. Lobato I, Friedrich T, Van Aert S, N P J Computational Materials 10, 10 (2024). http://doi.org/10.1038/s41524-023-01188-0
Abstract: Advanced electron microscopy techniques, including scanning electron microscopes (SEM), scanning transmission electron microscopes (STEM), and transmission electron microscopes (TEM), have revolutionized imaging capabilities. However, achieving high-quality experimental images remains a challenge due to various distortions stemming from the instrumentation and external factors. These distortions, introduced at different stages of imaging, hinder the extraction of reliable quantitative insights. In this paper, we will discuss the main sources of distortion in TEM and S(T)EM images, develop models to describe them, and propose a method to correct these distortions using a convolutional neural network. We validate the effectiveness of our method on a range of simulated and experimental images, demonstrating its ability to significantly enhance the signal-to-noise ratio. This improvement leads to a more reliable extraction of quantitative structural information from the images. In summary, our findings offer a robust framework to enhance the quality of electron microscopy images, which in turn supports progress in structural analysis and quantification in materials science and biology.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
DOI: 10.1038/s41524-023-01188-0
|
“Atom counting from a combination of two ADF STEM images”. Şentürk DG, Yu CP, De Backer A, Van Aert S, Ultramicroscopy 255, 113859 (2024). http://doi.org/10.1016/j.ultramic.2023.113859
Abstract: To understand the structure–property relationship of nanostructures, reliably quantifying parameters, such as the number of atoms along the projection direction, is important. Advanced statistical methodologies have made it possible to count the number of atoms for monotype crystalline nanoparticles from a single ADF STEM image. Recent developments enable one to simultaneously acquire multiple ADF STEM images. Here, we present an extended statistics-based method for atom counting from a combination of multiple statistically independent ADF STEM images reconstructed from non-overlapping annular detector collection regions which improves the accuracy and allows one to retrieve precise atom-counts, especially for images acquired with low electron doses and multiple element structures.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.2
DOI: 10.1016/j.ultramic.2023.113859
|
“In Situ Plasma Studies Using a Direct Current Microplasma in a Scanning Electron Microscope”. Grünewald L, Chezganov D, De Meyer R, Orekhov A, Van Aert S, Bogaerts A, Bals S, Verbeeck J, Advanced Materials Technologies (2024). http://doi.org/10.1002/admt.202301632
Abstract: Microplasmas can be used for a wide range of technological applications and to improve the understanding of fundamental physics. Scanning electron microscopy, on the other hand, provides insights into the sample morphology and chemistry of materials from the mm‐ down to the nm‐scale. Combining both would provide direct insight into plasma‐sample interactions in real‐time and at high spatial resolution. Up till now, very few attempts in this direction have been made, and significant challenges remain. This work presents a stable direct current glow discharge microplasma setup built inside a scanning electron microscope. The experimental setup is capable of real‐time in situ imaging of the sample evolution during plasma operation and it demonstrates localized sputtering and sample oxidation. Further, the experimental parameters such as varying gas mixtures, electrode polarity, and field strength are explored and experimental<italic>V</italic>–<italic>I</italic>curves under various conditions are provided. These results demonstrate the capabilities of this setup in potential investigations of plasma physics, plasma‐surface interactions, and materials science and its practical applications. The presented setup shows the potential to have several technological applications, for example, to locally modify the sample surface (e.g., local oxidation and ion implantation for nanotechnology applications) on the µm‐scale.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 6.8
DOI: 10.1002/admt.202301632
|
“Element specific atom counting for heterogeneous nanostructures: Combining multiple ADF STEM images for simultaneous thickness and composition determination”. Şentürk DG, De Backer A, Van Aert S, Ultramicroscopy 259, 113941 (2024). http://doi.org/10.1016/j.ultramic.2024.113941
Abstract: In this paper, a methodology is presented to count the number of atoms in heterogeneous nanoparticles based on the combination of multiple annular dark field scanning transmission electron microscopy (ADF STEM) images. The different non-overlapping annular detector collection regions are selected based on the principles of optimal statistical experiment design for the atom-counting problem. To count the number of atoms, the total intensities of scattered electrons for each atomic column, the so-called scattering cross-sections, are simultaneously compared with simulated library values for the different detector regions by minimising the squared differences. The performance of the method is evaluated for simulated Ni@Pt and Au@Ag core-shell nanoparticles. Our approach turns out to be a dose efficient alternative for the investigation of beam-sensitive heterogeneous materials as compared to the combination of ADF STEM and energy dispersive X-ray spectroscopy.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 2.2
DOI: 10.1016/j.ultramic.2024.113941
|