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“Methods and materials of the Amsterdam sunflowers”. Geldof M, Monico L, Johnson DH, Miliani C, Romani A, Grazia C, Buti D, Brunetti BG, Janssens K, Van der Snickt G, Vanmeert F page 85 (2019).
Abstract: This chapter explains the materials and techniques employed in the Amsterdam Sunflowers, enabling a comparison with the London version described in chapter 3. Building upon the 2016 article published in the National Gallery Technical Bulletin, it incorporates the latest findings gained by computer-assisted methods used to characterize the canvas support, as well as in-situ campaigns of non-invasive investigation together with further analysis of microscopic paint samples. The chapter sequence follows the steps in Van Gogh's working practice. Starting with the canvas, automated analysis of the weave enables the provenance of the canvas to be traced back to a particular roll of linen ordered by Van Gogh. Combining technical evidence with knowledge of historical manufacturing techniques further allows us to reconstruct the way in which Van Gogh divided his canvas roll into pieces used for Sunflowers and other paintings. We go on to consider how, with the original painting at hand, he used charcoal to transfer the motif of the London Sunflowers onto his blank canvas. Despite careful planning of the composition, an adjustment was required late in the working process, when Van Gogh added a painted wooden strip to extend the background above the flower at the top edge of the canvas. The artist's process of working up the composition in paint is described, paying special attention to his use of colour. The pigments and pigment mixtures used in the Amsterdam Sunflowers have been comprehensively mapped and are compared with the London picture, with discussion of some similarities and differences that account for the distinctive colour scheme of each painting. This understanding of colour application in the Amsterdam Sunflowers lays the foundation for subsequent chapters that will go on to consider the impact of light-induced colour changes that have taken place over time, and the related need to define appropriate lighting guidelines for the future safe preservation of this painting and others made with similar materials (chapters 5 and 7).
Keywords: H1 Book chapter; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
DOI: 10.1017/9789048550531.005
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Muys M (2019) Microbial protein as sustainable feed and food ingredient : production and nutritional quality of phototrophs and aerobic heterotrophs. 262 p
Abstract: In iets meer dan 30 jaar moeten we tot 50% meer eiwit produceren, terwijl onze conventionele lineaire voedselproductieketen reeds de grenzen van duurzaamheid overschrijdt. Microbieel eiwit (MP), de eiwitrijke biomassa van micro-organismen, werd onderzocht als nieuw voeder en voedselingrediënt in een circulaire eiwitproductieketen. MP-productie kan gebaseerd zijn op primaire grondstoffen om zo de inefficiënte stappen in de huidige eiwitproductie over te slaan, of de productie kan gebaseerd zijn op secundaire grondstoffen afkomstig van de verliezen in de conventionele productieketen (bijvoorbeeld afvalwater). Zowel indirecte als directe strategiën voor nutriëntenherwinning kunnen geïdentificeerd worden. Indirecte nutriëntenherwinning werd onderzocht door struviet toe te passen als fosfor- en stikstofbron voor MP-productie. Struviet, een herwinningsproduct in de afvalwaterzuivering, bleek een hoge zuiverheidsgraad te hebben waardoor het een uitstekende selectieve barrière vormt tussen afvalstroom en MP productie. Oplossingssnelheden en MP groei-experimenten toonden aan dat struviet gemakkelijk gedoseerd kan worden in functie van de microbiële nutriëntenbehoeftes, waarnaast problemen vermeden worden gerelateerd aan de turbiditeit van nevenstromen, wat de productie van fototrofe MP mogelijk maakt. Daarnaast werd ook directe nutriëntenherwinning onderzocht. Hierbij werden de voedingswaarde en veiligheid geanalyseerd van biomassa bestaande uit aerobe heterotrofe bacteriën (AHB) afkomstig van effluentzuivering van 25 bedrijven in de voedings- en drankensector. Verder werd ook de temporele variabiliteit in kaart gebracht. Er werd een veelbelovend eiwitgehalte geobserveerd waarvan de variabiliteit aanzienlijke was. Verder werd aangetoond dat het eiwitgehalte positief gecorreleerd was met stikstofbelasting en negatief met slibverblijftijd, wat een indicatie is dat de implementatie van een geoptimaliseerd productieproces, de biomassakwaliteit gevoelig kan verhogen. Bovendien was de veiligheid als veevoeder gegarandeerd op vlak van de meeste contaminanten. In het daarop volgende hoofdstuk werd de variabiliteit in voedingswaarde en veiligheid bestudeerd van commerciële fototrofe MP (de microalgen Chlorella en Spirulina), gekweekt op primaire grondstoffen. De waargenomen variabiliteit in voedingswaarde vereist verdere optimalisatie van het productieproces. Er werd ook waargenomen dat een hoog eiwitgehalte geen hoge totale voedingswaarde impliceert, omdat de verteerbaarheid en de eiwitkwaliteit nog steeds ongunstig kunnen zijn. Op basis van gemeten contaminanten geeft een veilige consumptiedosis aan dat microalgen perfect kunnen worden geconsumeerd als volwaardige eiwitbron in plaats van als supplement, hun huidige hoofdtoepassing. In een laatste experimenteel hoofdstuk werd onderzocht hoe de variabiliteit in biomassakwaliteit van microalgen kan worden gereduceerd en hoe een stabiele, hoogwaardige biomassaproductie kan worden bekomen. De invloed van oogsttijd, operationele modus en fotoperiode werd bepaald op de productiviteit van biomassa, eiwit en essentiële aminozuren en er werden optimale productieparameters geïdentificeerd. Samengevat is MP-productie op basis van indirecte en directe nutriëntenherwinning veelbelovend. Verdere technologische ontwikkelingen en het verhogen van bewustwording en sociale acceptatie, moeten een verdere introductie van MP in de voeder- en voedingsmarkt faciliteren. Hier kan MP een belangrijke oplossing vertegenwoordigen om de exponentieel groeiende wereldbevolking op een duurzame manier te voeden.
Keywords: Doctoral thesis; Sustainable Energy, Air and Water Technology (DuEL)
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“PCR amplified DNAzyme-amplicons for generic solid-phase antimicrobial resistance screening”. Peeters B, Safdar S, Carlier B, Spasic D, Daems D, Lammertyn J, , 971 (2019)
Abstract: Fiber optic surface plasmon resonance (FO-SPR) has shown its potential for the detection of nucleic acids and more recently the technology has been combined with catalytic active strands such as DNAzymes. In this work, an innovative, generic solid-phase DNA sensor concept is presented, based on FO-SPR and PCR amplified DNAzyme activity. Improved levels of specificity and sensitivity were obtained down to picomolar concentrations. Moreover, the FO-SPR sensor concept enables AuNP amplified DNA target detection, independent of the target sequence length. The FO-SPR sensor was demonstrated for the screening of the mobile colistin resistance (MCR-2) gene, a gene important for the antimicrobial resistance in Gram-negative species such as E. Coli.
Keywords: P1 Proceeding; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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Blommaerts N (2019) Plasmonic core shell nanoparticles : from synthesis to photocatalytic applications. 153 p
Abstract: Het gebruik van plasmon-actieve nanodeeltjes heeft de laatste 10 jaar zeer veel interesse gewekt bij onderzoekers in verschillende toepassingsdomeinen zoals fotokatalyse of oppervlakte versterkte Raman spectroscopie. Er is echter een grote limiterende factor bij het gebruik van edelmetaal nanodeeltjes zoals goud en zilver en dat is de stabiliteit. Deze oxideren en aggregeren snel, zeker in oxidatieve omgeving zoals in lucht. Een interessante aanpak om plasmon-actieve nanodeeltjes te stabiliseren, is om ze te omgeven in een schil, met andere woorden om een kern-schil nanodeeltje te vormen. Er zijn een heel aantal verschillende manieren waarop kern-schil nanodeeltjes gesynthetiseerd kunnen worden. In eerste instantie werden metaal nanodeeltjes omgeven door een (dunne) TiO2 laag. Afhankelijk van de hoeveelheid TiO2 precursor kon de dikte van de laag gecontroleerd worden tot enkele nanometers dik. De stalen werden getest voor de fotokatalytische afbraak van een vaste laag stearinezuur waarbij toevoeging van 2 wt% metaal@TiO2 op P25 leidde tot een significante verbetering in afbraakefficiëntie in vergelijking met zuiver P25. Een andere manier voor het stabiliseren van metaal nanodeeltjes is door ze te omgeven met een polymeerschil. Op deze manier kon de laagdikte gecontroleerd worden met sub-nanometer controle wat een zeer belangrijke factor is voor de hoeveelheid near-field versterking dat buiten de polymeer schil kan gaan. Een XTT test werd uitgevoerd om te bepalen wat de zuurstofactivatie snelheid was van goud en zilver (en goud-zilver bimetallische) nanodeeltjes, al dan niet omgeven door een (niet-)geleidende polymeer laag. Wanneer de stalen gecoat werden met vier niet-geleidende polymeerlagen zakte de zuurstofactivatie nagenoeg tot nul. Aan de andere kant, als goud nanodeeltjes werden omgeven door een geleidende schil was er nog steeds zuurstofactivatie, hoewel lager dan in het geval van goud zonder laag. Het laatste deel van deze thesis focuste meer op mogelijke toepassingen in luchtzuivering. In dit werk werd een glazen buis, gecoat aan de binnenkant met (Ag@polymer gemodificeerd) TiO2, als een spiraal rond een UVA lamp gewikkeld. De geoptimaliseerde spiraalreactor werd dan vergeleken met een conventionele cilindervormige fotoreactor, met dezelfde dimensies en totale katalysatorbelading, over een grote range aan experimentele condities. Uit de resultaten bleek dat de spiraalreactor significant betere afbraakefficiënties vertoonde in vergelijking met de conventionele cilindervormige reactor over een grote range aan debieten. Een adsorptiestap in combinatie met de geoptimaliseerde spiraalreactor zou kunnen leiden tot een zeer krachtige luchtzuiveringstechnologie.
Keywords: Doctoral thesis; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
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Sui Y (2019) Producing nutritional protein with Dunaliella microalgae : technological and economic optimization. 140 p
Abstract: In this thesis, microalga Dunaliella salina is highlighted as a novel source of protein to sustain the human needs. As demonstrated in this thesis, the biochemical composition of D. salina is not fixed, and can be substantially influenced by internal and external conditions. In order to comply with the human requirement of protein, various important factors affecting the protein quantity and quality of D. salina have been evaluated in this thesis for an optimized production strategy. All tested parameters, namely salinity, pH, light regimes (continuous light and light/dark cycle), light intensity, nutrient levels and growth phases can contribute to significant variations of protein content and essential amino acid (EAA) level in D. salina. Ultimately, D. salina is capable of producing high amount of superior quality protein, complying with the FAO reference for human consumption. Even better, such protein of superior quality can be accompanied by unique β-carotene accumulation in D. salina, a pigment with anti-oxidant pro-vitamin A effect. In the end, according to the techno-economic analysis (TEA), it is economically feasible to produce D. salina biomass for human nutrition.
Keywords: Doctoral thesis; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
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Alloul A (2019) Purple bacteria as microbial protein source : technology development, community control, economic optimization and biomass valorization. 212 p
Abstract: Food production is a cornerstone in contemporary industrial societies. Its production requires land, water and enormous amounts of fertilizers. These precious fertilizers enter the linear food chain and suffer from a cascade of inefficiencies, resulting in detrimental effects to the environment. A radical transforming of the current food production chain is, therefore, essential to guarantee a sustainable future for humanity. This thesis has studied the production of microbial protein (i.e. single-cell protein), which is the use of microorganisms such as yeast, fungi, algae and bacteria as protein ingredient for animal feed. The type of microorganisms targeted in this thesis were purple non-sulfur bacteria (PNSB). These bacteria are an extremely heterogenic group that contain photosynthetic pigments and are able to perform anoxygenic photosynthesis. The core focus of the thesis was technology development for the production of PNSB as a source of microbial protein on wastewater and fresh fertilizers. In the final stage of this research, it was the objective to explore the potential of PNSB as a nutritious feed ingredient for shrimp. Overall, this work has provided the building blocks to transform the conventional food production chain. The findings show that PNSB production and biomass valorization is within reach. Further pilot implementation and cost reduction will facilitate the introduction of PNSB production in future’s wastewater treatment plants and the valorization of the biomass as nutritious animal feed ingredient.
Keywords: Doctoral thesis; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
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Ghasemitarei M (2019) Study of the interaction of plasma radicals with malignant tumor cells by means of Molecular Dynamics simulation. 117 p
Abstract: abstract not available
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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Taghizadeh Sisakht E (2019) Tight-binding investigation of the electronic properties of phosphorene and phosphorene nanoribbons. 150 p
Abstract: abstract not available
Keywords: Doctoral thesis; Condensed Matter Theory (CMT)
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“Velázquez? A portrait of Pope Innocent X : an X-ray imaging investigation (II)”. Vanmeert F, Van der Snickt G, Legrand S, Janssens K page 132 (2019).
Abstract: Encompassing a broad spectrum of methodological approaches and aims, the scholars contributing to this volume offer renewed perspectives on the multifaceted oeuvre of Diego Velázquez. The seventeenth-century artist’s exceptional religious works as well as his numerous portraits are examined within the social and historical context of Velázquez’s milieu which included both the Spanish court as well as circles comprising important intellectual figures of his time. Following a close investigation of his works, which also includes the results of recent technological examinations on his paintings, the contributors to this volume offer new, exciting findings and discussions on the inspirations, sources and possible intentions of Velázquez.
Keywords: H3 Book chapter; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Laurdan as a molecular rotor in biological environments”. Osella S, Knippenberg S, ACS applied bio materials 2, 5769 (2019). http://doi.org/10.1021/ACSABM.9B00789
Abstract: Laurdan is one of the most used fluorescent probes for lipid membrane phase recognition. Despite its wide use for optical techniques and its versatility as a solvatochromic probe, little is known regarding its use as molecular rotor, for which clear evidence is found in the current study. Although recent computational and experimental studies suggest the existence of two stable conformations of laurdan in different membrane phases, it is difficult to experimentally probe their prevalence. By means of multiscale computational approaches, we prove now that this information can be obtained through the optical properties of the two conformers, ranging from one-photon absorption over two-photon absorption to the first hyperpolarizability. Fluorescence decay and anisotropy analyses are performed as well and stress the importance of laurdan's conformational versatility. As a molecular rotor and with reference to the distinct properties of its conformers, laurdan can be used to probe biochemical processes that change the lipid orders in cell membranes.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
DOI: 10.1021/ACSABM.9B00789
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“Achieving Fast Kinetics and Enhanced Li Storage Capacity for Ti3C2O2 by Intercalation of Quinone Molecules”. Siriwardane EMD, Demiroglu I, Sevik C, Cakir D, ACS applied energy materials 2, 1251 (2019). http://doi.org/10.1021/ACSAEM.8B01801
Abstract: Using first-principles calculations, we demonstrated that high lithium storage capacity and fast kinetics are achieved for Ti3C2O2 by preintercalating organic molecules. As a proof-of-concept, two different quinone molecules, namely 1,4-benzoquinone (C6H4O2) and tetrafluoro-1,4-benzoquinone (C6F4O2) were selected as the molecular linkers to demonstrate the feasibility of this interlayer engineering strategy for energy storage. As compared to Ti3C2O2 bilayer without linker molecules, our pillared structures facilitate a much faster ion transport, promising a higher charge/discharge rate for Li. For example, while the diffusion barrier of a single Li ion within pristine Ti3C2O2 bilayer is at least 1.0 eV, it becomes 0.3 eV in pillared structures, which is comparable and even lower than that of commercial materials. At high Li concentrations, the calculated diffusion barriers are as low as 0.4 eV. Out-of-plane migration of Li ions is hindered due to large barrier energy with a value of around 1-1.35 eV. Concerning storage capacity, we can only intercalate one monolayer of Li within pristine Ti3C2O2 bilayer. In contrast, pillared structures offer significantly higher storage capacity. Our calculations showed that at least two layers of Li can be intercalated between Ti3C2O2 layers without forming bulk Li and losing the pillared structure upon Li loading/unloading. A small change in the in-plane lattice parameters (<0.5%) and volume (<1.0%) and ab initio molecular dynamics simulations prove the stability of the pillared structures against Li intercalation and thermal effects. Intercalated molecules avoid the large contraction/expansion of the whole structure, which is one of the key problems in electrochemical energy storage. Pillared structures allow us to realize electrodes with high capacity and fast kinetics. Our results open new research paths for improving the performance of not only MXenes but also other layered materials for supercapacitor and battery applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
DOI: 10.1021/ACSAEM.8B01801
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“Real-time FO-SPR monitoring of solid-phase DNAzyme cleavage activity for cutting-edge biosensing”. Peeters B, Daems D, Van der Donck T, Delport F, Lammertyn J, ACS applied materials and interfaces 11, 6759 (2019). http://doi.org/10.1021/ACSAMI.8B18756
Abstract: DNA nanotechnology has a great potential in biosensor design including nanostructuring of the biosensor surface through DNA origami, target recognition by means of aptamers, and DNA-based signal amplification strategies. In this paper, we use DNA nanotechnology to describe for the first time the concept of real-time solid-phase monitoring of DNAzyme cleavage activity for the detection of specific single-stranded DNA (ssDNA) with a fiber optic surface plasmon resonance (FO-SPR) biosensor. Hereto, we first developed a robust ligation strategy for the functionalization of the FO-SPR biosensing surface with ssDNA-tethered gold nanoparticles, serving as the substrate for the DNAzyme. Next, we established a relation between the SPR signal change, due to the cleavage activity of the 10–23 DNAzyme, and the concentration of the DNAzyme, showing faster cleavage kinetics for higher DNAzyme concentrations. Finally, we implemented this generic concept for biosensing of ssDNA target in solution. Hereto, we designed a DNAzyme–inhibitor complex, consisting of an internal loop structure complementary to the ssDNA target, that releases active DNAzyme molecules in a controlled way as a function of the target concentration. We demonstrated reproducible target detection with a theoretical limit of detection of 1.4 nM, proving that the presented ligation strategy is key to a universal DNAzyme-based FO-SPR biosensing concept with promising applications in the medical and agrofood sector.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/ACSAMI.8B18756
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“Controlling the bioreceptor spatial distribution at the nanoscale for single molecule counting in microwell arrays”. Daems D, Rutten I, Bath J, Decrop D, Van Gorp H, Pérez Ruiz E, De Feyter S, Turberfield AJ, Lammertyn J, ACS sensors 4, 2327 (2019). http://doi.org/10.1021/ACSSENSORS.9B00877
Abstract: The ability to detect low concentrations of protein biomarkers is crucial for the early-stage detection of many diseases and therefore indispensable for improving diagnostic devices for healthcare. Here, we demonstrate that by integrating DNA nanotechnologies like DNA origami and aptamers, we can design innovative biosensing concepts for reproducible and sensitive detection of specific targets. DNA origami structures decorated with aptamers were studied as a novel tool to structure the biosensor surface with nanoscale precision in a digital detection bioassay, enabling control of the density, orientation, and accessibility of the bioreceptor to optimize the interaction between target and aptamer. DNA origami was used to control the spatial distribution of an in-house-generated aptamer on superparamagnetic microparticles, resulting in an origami-linked digital aptamer bioassay to detect the main peanut antigen Ara h1 with 2-fold improved signal-to-noise ratio and 15-fold improved limit of detection compared to a digital bioassay without DNA origami. Moreover, the sensitivity achieved was 4 orders of magnitude higher than commercially available and literature-reported enzyme-linked immunosorbent assay techniques. In conclusion, this novel and innovative approach to engineer biosensing interfaces will be of major interest to scientists and clinicians looking for new molecular insights and ultrasensitive detection of a broad range of targets, and, for the next generation of diagnostics.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/ACSSENSORS.9B00877
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“Bio-based aromatic amines from lignin-derived monomers”. Blondiaux E, Bomon J, Smolen M, Kaval N, Lemière F, Sergeyev S, Diels L, Sels B, Maes BUW, ACS Sustainable Chemistry and Engineering 7, 6906 (2019). http://doi.org/10.1021/ACSSUSCHEMENG.8B06467
Abstract: A new approach to synthesize valuable 3,4-dialkoxyanilines and alkyl propionates from lignin-derived 4-propylguaiacol and -catechol with overall isolated yields up to 65% has been described. The strategy is based on the introduction of nitrogen via a Beckmann rearrangement. Amino introduction therefore coincides with a C-defunctionalization reaction; overall a replacement of the propyl chain by an amino group is obtained. The process only requires cheap bulk chemicals as reagents/reactants and does not involve column chromatography to purify the reaction products. Furthermore, all carbon atoms from the biorenewable lignin-derived monomers are transformed into valuable compounds. Greenness was assessed by performing a Green Metrics analysis on two dialkoxyanilines. A comparison was made with literature routes for these compounds starting from a petrochemical substrate.
Keywords: A1 Journal article; Engineering sciences. Technology; Organic synthesis (ORSY); Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1021/ACSSUSCHEMENG.8B06467
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“An experimental and numerical study of the suppression of jets, counterflow, and backflow in vortex units”. Kulkarni S, Gonzalez-Quiroga A, Nuñez M, Schuerewegen C, Perreault P, Goel C, Heynderickx GJ, Van Geem KM, Marin GB, AIChE journal 65, e16614 (2019). http://doi.org/10.1002/AIC.16614
Abstract: Vortex units are commonly considered for various single and multiphase applications due to their process intensification capabilities. The transition from gas‐only flow to gas–solid flow remains largely unexplored nonetheless. During this transition, primary flow phenomenon, jets, and secondary flow phenomena, counterflow and backflow, are substantially reduced, before a rotating solids bed is established. This transitional flow regime is referred to as the vortex suppression regime. In the present work, this flow transition is identified and validated through experimental and computational studies in two vortex units with a scale differing by a factor of 2, using spherical aluminum and alumina particles. This experimental data supports the proposed theoretical particle monolayer solids loading that allows estimation of vortex suppression regime solids capacity for any vortex unit. It is shown that the vortex suppression regime is established at a solids loading theoretically corresponding to a monolayer being formed in the unit for 1g‐Geldart D‐ and 1g‐Geldart B‐type particles. The model closely agrees with experimental vortex suppression range for both aluminum and alumina particles. The model, as well as the experimental data, shows that the flow suppression regime depends on unit dimensions, particle diameter, and particle density but is independent of gas flow rate. This combined study, based on experimental and computational data and on a theoretical model, reveals the vortex suppression to be one of the basic operational parameters to study flow in a vortex unit and that a simple monolayer model allows to estimate the needed solids loading for any vortex device to induce this flow transition.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1002/AIC.16614
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“Revealing the distribution of metal carboxylates in oil paint from the micro- to nanoscale”. Ma X, Beltran V, Ramer G, Pavlidis G, Parkinson DY, Thoury M, Meldrum T, Centrone A, Berrie BH, Angewandte Chemie: international edition in English 58, 11652 (2019). http://doi.org/10.1002/ANIE.201903553
Abstract: Oil paints comprise pigments, drying oils, and additives that together confer desirable properties, but can react to form metal carboxylates (soaps) that may damage artworks over time. To obtain information on soap formation and aggregation, we introduce a new tapping-mode measurement paradigm for the photothermal induced resonance (PTIR) technique that enables nanoscale IR spectroscopy and imaging on highly heterogenous and rough paint thin sections. PTIR is used in combination with mu-computed tomography and IR microscopy to determine the distribution of metal carboxylates in a 23-year old oil paint of known formulation. Results show that heterogeneous agglomerates of Al-stearate and a Zn-carboxylate complex with Zn-stearate nano-aggregates in proximity are distributed randomly in the paint. The gradients of zinc carboxylates are unrelated to the Al-stearate distribution. These measurements open a new chemically sensitive nanoscale observation window on the distribution of metal soaps that can bring insights for understanding soap formation in oil paint.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/ANIE.201903553
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“Media optimization, strain compatibility, and low-shear modeled microgravity exposure of synthetic microbial communities for urine nitrification in regenerative life-support systems”. Ilgrande C, Defoirdt T, Vlaeminck SE, Boon N, Clauwaert P, Astrobiology 19, 1353 (2019). http://doi.org/10.1089/AST.2018.1981
Abstract: Urine is a major waste product of human metabolism and contains essential macro- and micronutrients to produce edible microorganisms and crops. Its biological conversion into a stable form can be obtained through urea hydrolysis, subsequent nitrification, and organics removal, to recover a nitrate-enriched stream, free of oxygen demand. In this study, the utilization of a microbial community for urine nitrification was optimized with the focus for space application. To assess the role of selected parameters that can impact ureolysis in urine, the activity of six ureolytic heterotrophs (Acidovorax delafieldii, Comamonas testosteroni, Cupriavidus necator, Delftia acidovorans, Pseudomonas fluorescens, and Vibrio campbellii) was tested at different salinities, urea, and amino acid concentrations. The interaction of the ureolytic heterotrophs with a nitrifying consortium (Nitrosomonas europaea ATCC 19718 and Nitrobacter winogradskyi ATCC 25931) was also tested. Lastly, microgravity was simulated in a clinostat utilizing hardware for in-flight experiments with active microbial cultures. The results indicate salt inhibition of the ureolysis at 30 mS cm(-1), while amino acid nitrogen inhibits ureolysis in a strain-dependent manner. The combination of the nitrifiers with C. necator and V. campbellii resulted in a complete halt of the urea hydrolysis process, while in the case of A. delafieldii incomplete nitrification was observed, and nitrite was not oxidized further to nitrate. Nitrate production was confirmed in all the other communities; however, the other heterotrophic strains most likely induced oxygen competition in the test setup, and nitrite accumulation was observed. Samples exposed to low-shear modeled microgravity through clinorotation behaved similarly to the static controls. Overall, nitrate production from urea was successfully demonstrated with synthetic microbial communities under terrestrial and simulated space gravity conditions, corroborating the application of this process in space.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1089/AST.2018.1981
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“Reactivation of microbial strains and synthetic communities after a spaceflight to the International Space Station : corroborating the feasibility of essential conversions in the MELiSSA Loop”. Ilgrande C, Mastroleo F, Christiaens MER, Lindeboom REF, Prat D, Van Hoey O, Ambrozova I, Coninx I, Heylen W, Pommerening-Roser A, Spieck E, Boon N, Vlaeminck SE, Leys N, Clauwaert P, Astrobiology 19, 1167 (2019). http://doi.org/10.1089/AST.2018.1973
Abstract: To sustain human deep space exploration or extra-terrestrial settlements where no resupply from the Earth or other planets is possible, technologies for in situ food production, water, air, and waste recovery need to be developed. The Micro-Ecological Life Support System Alternative (MELiSSA) is such a Regenerative Life Support System (RLSS) and it builds on several bacterial bioprocesses. However, alterations in gravity, temperature, and radiation associated with the space environment can affect survival and functionality of the microorganisms. In this study, representative strains of different carbon and nitrogen metabolisms with application in the MELiSSA were selected for launch and Low Earth Orbit (LEO) exposure. An edible photoautotrophic strain (Arthrospira sp. PCC 8005), a photoheterotrophic strain (Rhodospirillum rubrum S1H), a ureolytic heterotrophic strain (Cupriavidus pinatubonensis 1245), and combinations of C. pinatubonensis 1245 and autotrophic ammonia and nitrite oxidizing strains (Nitrosomonas europaea ATCC19718, Nitrosomonas ureae Nm10, and Nitrobacter winogradskyi Nb255) were sent to the International Space Station (ISS) for 7 days. There, the samples were exposed to 2.8 mGy, a dose 140 times higher than on the Earth, and a temperature of 22 degrees C +/- 1 degrees C. On return to the Earth, the cultures were reactivated and their growth and activity were compared with terrestrial controls stored under refrigerated (5 degrees C +/- 2 degrees C) or room temperature (22 degrees C +/- 1 degrees C and 21 degrees C +/- 0 degrees C) conditions. Overall, no difference was observed between terrestrial and ISS samples. Most cultures presented lower cell viability after the test, regardless of the type of exposure, indicating a harsher effect of the storage and sample preparation than the spaceflight itself. Postmission analysis revealed the successful survival and proliferation of all cultures except for Arthrospira, which suffered from the premission depressurization test. These observations validate the possibility of launching, storing, and reactivating bacteria with essential functionalities for microbial bioprocesses in RLSS.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1089/AST.2018.1973
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“Nonlinear dispersive model of electroporation for irregular nucleated cells”. Chiapperino MA, Bia P, Caratelli D, Gielis J, Mescia L, Dermol-Cerne J, Miklavcic D, Bioelectromagnetics 40, 331 (2019). http://doi.org/10.1002/BEM.22197
Abstract: In this work, the electroporation phenomenon induced by pulsed electric field on different nucleated biological cells is studied. A nonlinear, non-local, dispersive, and space-time multiphysics model based on Maxwell's and asymptotic Smoluchowski's equations has been developed to calculate the transmembrane voltage and pore density on both plasma and nuclear membrane perimeters. The irregular cell shape has been modeled by incorporating in the numerical algorithm the analytical functions pertaining to Gielis curves. The dielectric dispersion of the cell media has been modeled considering the multi-relaxation Debye-based relationship. Two different irregular nucleated cells have been investigated and their response has been studied applying both the dispersive and non-dispersive models. By a comparison of the obtained results, differences can be highlighted confirming the need to make use of the dispersive model to effectively investigate the cell response in terms of transmembrane voltages, pore densities, and electroporation opening angle, especially when irregular cell shapes and short electric pulses are considered. Bioelectromagnetics. 2019;40:331-342. (c) 2019 Wiley Periodicals, Inc.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1002/BEM.22197
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“Enhancement of co-production of nutritional protein and carotenoids in Dunaliella salina using a two-phase cultivation assisted by nitrogen level and light intensity”. Sui Y, Muys M, Van de Waal D, D'Adamo S, Vermeir P, Fernandes TV, Vlaeminck SE, Bioresource technology 287, 121398 (2019). http://doi.org/10.1016/J.BIORTECH.2019.121398
Abstract: Microalga Dunaliella salina is known for its carotenogenesis. At the same time, it can also produce high-quality protein. The optimal conditions for D. salina to co-produce intracellular pools of both compounds, however, are yet unknown. This study investigated a two-phase cultivation strategy to optimize combined high-quality protein and carotenoid production of D. salina. In phase-one, a gradient of nitrogen concentrations was tested. In phase-two, effects of nitrogen pulse and high illumination were tested. Results reveal optimized protein quantity, quality (expressed as essential amino acid index EAAI) and carotenoids content in a two-phase cultivation, where short nitrogen starvation in phase-one was followed by high illumination during phase-two. Adopting this strategy, productivities of protein, EAA and carotenoids reached 22, 7 and 3 mg/L/d, respectively, with an EAAI of 1.1. The quality of this biomass surpasses FAO/WHO standard for human nutrition, and the observed level of β-carotene presents high antioxidant pro-vitamin A activity.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.BIORTECH.2019.121398
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“High-rate activated sludge systems combined with dissolved air flotation enable effective organics removal and recovery”. Cagnetta C, Saerens B, Meerburg FA, Decru SO, Broeders E, Menkveld W, Vandekerckhove TGL, De Vrieze J, Vlaeminck SE, Verliefde ARD, De Gusseme B, Weemaes M, Rabaey K, Bioresource technology 291, 121833 (2019). http://doi.org/10.1016/J.BIORTECH.2019.121833
Abstract: High-rate activated sludge (HRAS) systems typically generate diluted sludge which requires further thickening prior to anaerobic digestion (AD), besides the need to add considerable coagulant and flocculant for the solids separation. As an alternative to conventional gravitational settling, a dissolved air flotation (DAF) unit was coupled to a HRAS system or a high-rate contact stabilization (HiCS) system. The HRAS-DAF system allowed up to 78% removal of the influent solids, and the HiCS-DAF 67%. Both were within the range of values typically obtained for HRAS-settler systems, albeit at a lower chemical requirement. The separated sludge had a high concentration of up to 47 g COD L−1, suppressing the need of further thickening before AD. Methanation tests showed a biogas yield of up to 68% on a COD basis. The use of a DAF separation system can thus enable direct organics removal at high sludge concentration and with low chemical needs.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.BIORTECH.2019.121833
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“High variability in nutritional value and safety of commercially available Chlorella and Spirulina biomass indicates the need for smart production strategies”. Muys M, Sui Y, Schwaiger B, Lesueur C, Vandenheuvel D, Vermeir P, Vlaeminck SE, Bioresource technology 275, 247 (2019). http://doi.org/10.1016/J.BIORTECH.2018.12.059
Abstract: Microalgal biomass production is a resource-efficient answer to the exponentially increasing demand for protein, yet variability in biomass quality is largely unexplored. Nutritional value and safety were determined for Chlorella and Spirulina biomass from different producers, production batches and the same production batch. Chlorella presented a similar protein content (47 ± 8%) compared to Spirulina (48 ± 4%). However, protein quality, expressed as essential amino acid index, and digestibility were lower for Chlorella (1.1 ± 0.1 and 51 ± 9%, respectively) compared to Spirulina (1.3 ± 0.1 and 61 ± 4%, respectively). Generally, variability was lower between batches and within a batch. Heavy metals, pesticides, mycotoxins, antibiotics and nitrate did not violate regulatory limits, while polycyclic aromatic hydrocarbon levels exceeded the norm for some samples, indicating the need for continuous monitoring. This first systematic screening of commercial microalgal biomass revealed a high nutritional variability, necessitating further optimization of cultivation and post-processing conditions. Based on price and quality, Spirulina was preferred above Chlorella.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.BIORTECH.2018.12.059
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“Light regime and growth phase affect the microalgal production of protein quantity and quality with Dunaliella salina”. Sui Y, Muys M, Vermeir P, D'Adamo S, Vlaeminck SE, Bioresource technology 275, 145 (2019). http://doi.org/10.1016/J.BIORTECH.2018.12.046
Abstract: The microalga Dunaliella salina has been widely studied for carotenogenesis, yet its protein production for human nutrition has rarely been reported. This study unveils the effects of growth phase and light regime on protein and essential amino acid (EAA) levels in D. salina. Cultivation under 24-h continuous light was compared to 12-h/12-h light/dark cycle. The essential amino acid index (EAAI) of D. salina showed accumulating trends up to 1.53 in the stationary phase, surpassing FAO/WHO standard for human nutrition. Light/dark conditions inferred a higher light-usage efficiency, yielding 597% higher protein and 1828% higher EAA mass on light energy throughout the growth, accompanied by 138% faster growth during the light phase of the light/dark cycle, compared to continuous light. The findings revealed D. salina to be especially suitable for high-quality protein production, particularly grown under light/dark conditions, with nitrogen limitation as possible trigger, and harvested in the stationary phase.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.BIORTECH.2018.12.046
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“Resource recovery from pig manure via an integrated approach : a technical and economic assessment for full-scale applications”. De Vrieze J, Colica G, Pintucci C, Sarli J, Pedizzi C, Willeghems G, Bral A, Varga S, Prat D, Peng L, Spiller M, Buysse J, Colsen J, Benito O, Carballa M, Vlaeminck SE, Bioresource technology 272, 582 (2019). http://doi.org/10.1016/J.BIORTECH.2018.10.024
Abstract: Intensive livestock farming cannot be uncoupled from the massive production of manure, requiring adequate management to avoid environmental damage. The high carbon, nitrogen and phosphorus content of pig manure enables targeted resource recovery. Here, fifteen integrated scenarios for recovery of water, nutrients and energy are compared in terms of technical feasibility and economic viability. The recovery of refined nutrients with a higher market value and quality, i.e., (NH4)2SO4 for N and struvite for P, coincided with higher net costs, compared to basic composting. The inclusion of anaerobic digestion promoted nutrient recovery efficiency, and enabled energy recovery through electricity production. Co-digestion of the manure with carbon-rich waste streams increased electricity production, but did not result in lower process costs. Overall, key drivers for the selection of the optimal manure treatment scenario will include the market demand for more refined (vs. separated or concentrated) products, and the need for renewable electricity production.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.BIORTECH.2018.10.024
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“Aerodynamic characterisation of green wall vegetation based on plant morphology : an experimental and computational fluid dynamics approach”. Koch K, Samson R, Denys S, Biosystems engineering 178, 34 (2019). http://doi.org/10.1016/J.BIOSYSTEMSENG.2018.10.019
Abstract: The installation of urban green infrastructure, particularly green walls, has proven to be an effective strategy for the mitigation of particulate matter (PM) pollution and the urban heat island effect. For the interaction between vegetation, PM and the local microclimate, wind flow is the main driving force. In order to investigate these interactions in detail, it is important to know how air flows through vegetation. This study proposes a method based on the DarcyForchheimer equation, where vegetation is considered as a porous medium and several plant species and the effects of plant morphological characteristics are examined both experimentally and using computer simulations. Results showed that the DarcyForchheimer model is a simple and robust way to describe air flow through vegetation regardless of its morphology. This research provides a new vision on studying aerodynamic properties of vegetation in relation to their morphology and provides opportunities for model the interaction between vegetation and its environment.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.BIOSYSTEMSENG.2018.10.019
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“Climatic quality evaluation by peak analysis and segregation of low-, mid-, and high-frequency fluctuations, applied on a historic chapel”. Anaf W, Schalm O, Building and environment 148, 286 (2019). http://doi.org/10.1016/J.BUILDENV.2018.11.018
Abstract: Heritage-related guidelines and standards recommend stable climatic conditions, since these contribute to the extension of heritage collections life. As a result, numerous museums and other heritage institutions implement (expensive) mitigation measures to achieve stable conditions. Nevertheless, temperature and relative humidity fluctuations are often still observed. This contribution demonstrates that the analysis of temperature and humidity peaks and drops helps to identify hazards which cause fluctuations in different frequency ranges. This hazard identification provides information on the type of mitigation actions that are required in the near future and in which order they need to be implemented. The approach is illustrated with a case study. A 22 month monitoring campaign was performed in a chapel in the center of Antwerp (Belgium) where the climatic conditions are controlled with a heating, ventilation and air conditioning (HVAC) system. Low-, mid- and high-frequency fluctuations were separated and discussed for their hazards.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
DOI: 10.1016/J.BUILDENV.2018.11.018
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“CFD-modelling of activated carbon fibers for indoor air purification”. Roegiers J, Denys S, Chemical engineering journal 365, 80 (2019). http://doi.org/10.1016/J.CEJ.2019.02.007
Abstract: Activated carbon fibers for indoor air purification were investigated by means of pressure drop and adsorption capacity. The Darcy-Forchheimer law combined with Computational Fluid Dynamics (CFD) modelling was deployed to simulate the pressure drop over an activated carbon fiber (ACF) filter with varying filter thickness. The CFD model was later combined with adsorption modelling to simulate breakthrough profiles of acetaldehyde adsorption on the ACF-filter. The adsorption model incorporates mass transfer resistance and adsorption equilibrium. It assumes local equilibrium between gas phase and solid phase. The latter was investigated for three different adsorption isotherms: linear, Langmuir and Freundlich adsorption. Successful agreement between model simulations and experimental data was obtained, using the Freundlich adsorption model. The numerical model could provide valuable insights and allows to continuously improve the design of filtration devices.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.CEJ.2019.02.007
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“Redox layer deposition of thin films of MnO2 on nanostructured substrates from aqueous solutions”. Zankowski SP, Van Hoecke L, Mattelaer F, de Raedt M, Richard O, Detavernier C, Vereecken PM, Chemistry of materials 31, 4805 (2019). http://doi.org/10.1021/ACS.CHEMMATER.9B01219
Abstract: In this work, we report a new method for depositing thin films of MnO2 on planar and complex nanostructured surfaces, with high precision and conformality. The method is based on repeating cycles of adsorption of an unsaturated alcohol on a surface, followed by its oxidation with aqueous KMnO4 and formation of thin, solid MnO2. The amount of manganese oxide formed in each cycle is limited by the quantity of the adsorbed alcohol; thus, the growth exhibits the self-limiting characteristics of atomic layer deposition (ALD). Contrary to the typical ALD, however, the new redox layer deposition is performed in air, at room temperature, using common chemicals and simple laboratory glassware, which greatly reduces its cost and complexity. We also demonstrate application of the method for the fabrication of a nanostructured MnO2/Ni electrode, which was not possible with thermal ALD because of the rapid decomposition of the gaseous precursor on the high surface-area substrate. Thanks to its simplicity, the conformal deposition of MnO2 can be easily upscaled and thus exploited for its numerous (electro)chemical applications.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1021/ACS.CHEMMATER.9B01219
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“Overcoming floc formation limitations in high-rate activated sludge systems”. Van Winckel T, Liu X, Vlaeminck SE, Takács I, Al-Omari A, Sturm B, Kjellerup BV, Murthy SN, De Clippeleir H, Chemosphere 215, 342 (2019). http://doi.org/10.1016/J.CHEMOSPHERE.2018.09.169
Abstract: High-rate activated sludge (HRAS) is an essential cornerstone of the pursuit towards energy positive sewage treatment through maximizing capture of organics. The capture efficiency heavily relies on the degree of solid separation achieved in the clarifiers. Limitations in the floc formation process commonly emerge in HRAS systems, with detrimental consequences for the capture of organics. This study pinpointed and overcame floc formation limitations present in full-scale HRAS reactors. Orthokinetic flocculation tests were performed with varying shear, sludge concentration, and coagulant or flocculant addition. These were analyzed with traditional and novel settling parameters and extracellular polymeric substances (EPS) measurements. HRAS was limited by insufficient collision efficiency and occurred because the solids retention time (SRT) was short and colloid loading was high. The limitation was predominantly caused by impaired flocculation rather than coagulation. In addition, the collision efficiency limitation was driven by EPS composition (low protein over polysaccharide ratio) instead of total EPS amount. Collision efficiency limitation was successfully overcome by bio-augmenting sludge from a biological nutrient removal reactor operating at long SRT which did not show any floc formation limitations. However, this action brought up a floc strength limitation. The latter was not correlated with EPS composition, but rather EPS amount and hindered settling parameters, which determined floc morphology. With this, an analysis toolkit was proposed that will enable design engineers and operators to tackle activated solid separation challenges found in HRAS systems and maximize the recovery potential of the process. (C) 2018 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.CHEMOSPHERE.2018.09.169
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“Bridging global, basin and local-scale water quality modeling towards enhancing water quality management worldwide”. Tang T, Strokal M, van Vliet MTH, Seuntjens P, Burek P, Kroeze C, Langan S, Wada Y, Current Opinion in Environmental Sustainability 36, 39 (2019). http://doi.org/10.1016/J.COSUST.2018.10.004
Abstract: Global water quality (WQ) modeling is an emerging field. In this article, we identify the missing linkages between global and basin/local-scale WQ models, and discuss the possibilities to fill these gaps. We argue that WQ models need stronger linkages across spatial scales. This would help to identify effective scale-specific WQ management options and contribute to future development of global WQ models. Two directions are proposed to improve the linkages: nested multiscale WQ modeling towards enhanced water management, and development of next-generation global WQ models based-on basin/local-scale mechanistic understanding. We highlight the need for better collaboration among WQ modelers and policy-makers in order to deliver responsive water policies and management strategies across scales.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.COSUST.2018.10.004
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