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“Investigating market power in the Belgian pork production chain”. Maes D, Vancauteren M, Van Passel S, Review of Agricultural, Food and Environmental Studies 100, 93 (2019). http://doi.org/10.1007/s41130-019-00096-6
Abstract: Belgian pork production has faced stagnating prices for decades. It remains unclear whether excessive market power from slaughterhouses or meat retailers has played a role in this trend. While market power studies can reveal some of the market dynamics in this setting, this type of research has not yet been applied to the Belgian pork market. The present paper investigates oligopolies and oligopsonies in the pork production sector. We build a new model that focuses on market power dynamics in the market for live pigs and distinguishes horizontal and vertical market power parameters, both for pig farmers and for slaughterhouses. The results follow from an empirical application using unique slaughterhouse data for 2001–2015. The results indicate that the farmers benefit from a significant power advantage in the live pig market, when very modest price demands are taken as a reference. The final market price of live pigs approaches the price requested by the farmers. On the other hand, the measured vertical market power also suggests that a pig farmer does not receive the (modest) full-wage-based salary. The market power of the slaughterhouses is also limited. Market power as a result of collusion—that is, horizontal market power—is present, but is not strong. However, there are significant differences between the slaughterhouses in terms of mark-up on the input prices. These differences reflect differences in company strategy, and this diversity further reduces the possibility to create sector-wide collusive behaviour.
Keywords: A1 Journal Article; Engineering Management (ENM) ;
DOI: 10.1007/s41130-019-00096-6
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“Adaptive capacity of smallholder farmers toward climate change: evidence from Hamadan province in Iran”. Jamshidi O, Asadi A, Kalantari K, Movahhed Moghaddam S, Dadrass Javan F, Azadi H, Van Passel S, Witlox F, Climate And Development , 1 (2020). http://doi.org/10.1080/17565529.2019.1710097
Abstract: The global climate is changing, and farmers must increase their adaptive capacity to avoid negative impacts. This study aimed to examine the adaptive capacity of farmers’ household to tolerate climate changes and identify factors affecting the climate in Hamadan province, Iran. The adaptive capacity was evaluated quantitatively by using 23 indicators and was categorized into high, moderate, low, and very low adaptive capacity. The study was based on a cross sectional survey and was conducted with a random sample of 280 household farmers distributed in five counties of Hamadan province in the west of the country whose climatic data revealed signs of climate change. The result showed that farmers’ negative perception toward climate change generally increases during dry seasons and decreases when the precipitation and water resources are more available. Regarding the available information, only 15% of farmers had a high level of adaptive capacity, while 10% of them were highly adapted, and 27.5% showed a very low level of adaptive capacity. Adaptive capacity in the current study was influenced by some socio-economic variables including total farm size, irrigated farm size, number of agricultural land plots, and perception and knowledge of climate change.
Keywords: A1 Journal Article; Adaptive capacity; cross sectional survey; socio-economic variables; adaptation strategies; Hamadan province; Engineering Management (ENM) ;
Impact Factor: 2.051
DOI: 10.1080/17565529.2019.1710097
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“Conflict, fraud, and distrust in Ethiopian agricultural cooperatives”. Sebhatu KT, Gezahegn TW, Berhanu T, Maertens M, Van Passel S, D’Haese M, Journal of Co-operative Organization and Management 8, 100106 (2020). http://doi.org/10.1016/j.jcom.2020.100106
Abstract: Agricultural cooperatives are seen as an efficient way for smallholder farmers to create bargaining power in order to achieve poverty reduction and food security. However, the success of these cooperatives depends on their ability to maintain their social capital, which is at the core of collective action. A few studies have addressed issues of member participation, commitment, and trust, yet less is known about rural cooperatives in developing countries as a social organization. It is also unclear whether a relationship exists between cooperative size and the incidence of conflict, fraud, and distrust. Using unique data collected from 511 agricultural cooperatives in 12 districts of Tigray region in northern Ethiopia, this paper examines the effects of cooperative size on conflict, fraud, and distrust. We used instrumental variables (IV) probit estimation techniques, accounting for endogeneity of membership size, to confirm that cooperative size does affect the occurrence of conflict, fraud, and trust. The results also indicate that other influencing factors include: cooperative age, number of employees, payment of dividends based on transaction volume, and heterogeneity of member goals.
Keywords: A1 Journal Article; Agricultural cooperatives; Cooperative size; Conflict; Fraud; Distrust; Ethiopia; Engineering Management (ENM) ;
DOI: 10.1016/j.jcom.2020.100106
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“Drought risk assessment: Towards drought early warning system and sustainable environment in western Iran”. Sharafi L, Zarafshani K, Keshavarz M, Azadi H, Van Passel S, Ecological Indicators 114, 106276 (2020). http://doi.org/10.1016/j.ecolind.2020.106276
Abstract: Prolonged drought is considered as a creeping natural hazard, which has created a financial burden and unsustainable environment in Iran. Moreover, the effect of drought phenomenon in rural areas is more extensive, causing significant challenges to the rural economy in general and agricultural production in particular. A common strategy to manage drought is based on crisis management (ex-ante). However, for effective drought management, risk management seems to be more in line with drought early warning systems. This quantitative study used risk assessment, which is the function of two elements such as hazard (SPI and SDI indices) and vulnerability (exposure, sensitivity, and adaptive capacity). This study aims to build the foundations for drought early warning systems in limited resource areas such as Kermanshah Township in the northwestern part of Iran. The population of this study comprised of wheat farmers in which 293 farmers were selected using multistage cluster sampling method. In the next step, the drought risk map for Kermanshah Township was developed, which revealed that the majority of villages are at intense environmental risk. The result of this study has implications for drought management practitioners. For example, the results can aid policymakers in the design of an early warning system in order to reduce risk and thus empower farmers toward resilient farming.
Keywords: A1 Journal Article; Drought; Early warning system; Risk management; Vulnerability; Environmental risk; Resilient farming; Engineering Management (ENM) ;
DOI: 10.1016/j.ecolind.2020.106276
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“Modeling the Impact of Urbanization on Land-Use Change in Bahir Dar City, Ethiopia: An Integrated Cellular Automata–Markov Chain Approach”. Fitawok MB, Derudder B, Minale AS, Van Passel S, Adgo E, Nyssen J, Land 9, 115 (2020). http://doi.org/10.3390/land9040115
Abstract: The fast-paced urbanization of recent decades entails that many regions are facing seemingly uncontrolled land-use changes (LUCs) that go hand in hand with a range of environmental and socio-economic challenges. In this paper, we use an integrated cellular automata–Markov chain (CA–MC) model to analyze and predict the urban expansion of and its impact on LUC in the city of Bahir Dar, Ethiopia. To this end, the research marshals high-resolution Landsat images of 1991, 2002, 2011, and 2018. An analytical hierarchy process (AHP) method is then used to identify the biophysical and socioeconomic factors underlying the expansion in the research area. It is shown that, during the period of study, built-up areas are rapidly expanding in the face of an overall decline of the farmland and vegetation cover. Drawing on a model calibration for 2018, the research predicts the possible geographies of LUC in the Bahir Dar area for 2025, 2034, and 2045. It is predicted that the conversions of other land-use types into built-up areas will persist in the southern, southwestern, and northeastern areas of the sprawling city, which can mainly be traced back to the uneven geographies of road accessibility, proximity to the city center, and slope variables. We reflect on how our findings can be used to facilitate sustainable urban development and land-use policies in the Bahir Dar area.
Keywords: A1 Journal Article; analytical hierarchy process; cellular automata; land-use change; Markov chain; urbanization; Engineering Management (ENM) ;
DOI: 10.3390/land9040115
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“Climate-Smart Agriculture in the Northeast of Brazil: An Integrated Assessment of the Aquaponics Technology”. Finizola e Silva M, Van Passel S, Sustainability 12, 3734 (2020). http://doi.org/10.3390/su12093734
Abstract: The purpose of this study is to determine if aquaponic systems can reduce food insecurity in the semi-arid regions of Brazil and generate income for the beneficiaries. Aquaponics is a potentially sustainable way to produce food based on gardening, hydroponics and aquaculture. A case study, based on a project called Aquaponova, was developed. The aquaponic systems currently used in the project are non-commercial and designed for households with limited resources. The data based on six existing systems within this project were used to compare the costs and the benefits. The cost–benefit analysis covers four scenarios and three financing options. The results show that aquaponic systems have a large potential and can reduce food insecurity in semi-arid regions while generating income for the beneficiaries. Even if the system only produces 40% of the total estimated production, the system will still be feasible. However, the low opportunity cost of labour is an essential factor for obtaining these positive results. Moreover, the social benefits, such as a community spirit and the health benefits of the system, should not be underestimated.
Keywords: A1 Journal Article; aquaponics; Aquaponova; Brazil; semi-arid region; food insecurity; cost–benefit analysis; socio-economic approach; climate-smart agriculture; Engineering Management (ENM) ;
Impact Factor: 3.9
DOI: 10.3390/su12093734
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“Integrated techno-economic assessment of a biorefinery process: The high-end valorization of the lignocellulosic fraction in wood streams”. Tschulkow M, Compernolle T, Van den Bosch S, Van Aelst J, Storms I, Van Dael M, Van den Bossche G, Sels B, Van Passel S, Journal Of Cleaner Production 266, 122022 (2020). http://doi.org/10.1016/j.jclepro.2020.122022
Abstract: A new lignin-first biorefinery with a reductive catalytic fractionation process, which targets the valorization of the lignin and the carbohydrate fraction into higher value end-products, is currently being designed. To identify the various R&D drivers for projects with a low technology readiness level (TRL), we developed an integrated techno-economic assessment (TEA) that directly integrates the results of lab studies with economic costs and benefits. Furthermore, different linkages are made to upstream wood availability and downstream demand to understand its fit into existing wood value chains. By making the relations across the wood value chain explicit within the integrated TEA, we find that the scale of the plant, the feedstock-specific output quantities, and output prices highly determine the economic feasibility. Furthermore, this detailed analysis reveals the importance of assessing different types of feedstock. If only virgin wood is available as feedstock, minimum capacity levels between 190 and 234 kilotons per year are needed for the investment to be profitable. Waste wood proves to be the most profitable feedstock with an NPV of M€ 59 and an IRR of 26%. Using only waste wood as feedstock makes the investment profitable at a lower capacity level of 80 kilotons per year and economic shocks can be absorbed. Based on these results we show that an integrated and detailed TEA is indispensable to define future development paths for early-stage, innovative technologies.
Keywords: A1 Journal Article; Engineering Management (ENM) ;
Impact Factor: 11.1
DOI: 10.1016/j.jclepro.2020.122022
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“Urban green infrastructure: A review on valuation toolkits from an urban planning perspective”. Van Oijstaeijen W, Van Passel S, Cools J, Journal Of Environmental Management 267, 110603 (2020). http://doi.org/10.1016/j.jenvman.2020.110603
Abstract: As a response to increasing urbanization and changing weather and climatic patterns, urban green infrastructure (UGI) emerged as a concept to increase resilience within the urban boundaries. Given that implementing these (semi-) natural solutions in practice requires a clear overview of the costs and benefits, valuation becomes ever important. A range of decision-support tools for green infrastructure and ecosystem services exist, developed for various purposes. This paper reviews the potential of 10 shortlisted and existing valuation tools to support investment decisions of urban green infrastructure. In the assessment, the functionality is regarded specifically from the urban planning and decision-making viewpoint. The toolkits were evaluated on 12 different criteria. After analyzing the toolkits on these criteria, the findings are evaluated on the (mis)match with specific requirements in the urban planning and management context. Secondly, recommendations and guidelines are formulated to support the design of simple valuation tools, tailored to support the development of green infrastructure in urban areas. Approaching the valuation toolkits biophysically and (socio-)economically provides an integral overview of the challenges and opportunities of the capacities of each framework. It was found that most tools are not designed for the peculiarities of the urban context. Several elements contribute to the hampering uptake of GI valuation tools. Firstly, the limited effort in the economic case for green infrastructure remains a burden to use toolkits to compare grey and green alternatives. Secondly, tools are currently seldom designed for the peculiarities of cities: urban ecosystem (dis)services, multi-scalability, life-span assessments of co-benefits and the importance of social benefits. Thirdly, toolkits should be the result of co-development between the scientific community and local authorities in order to create toolkits that are tailor made to the specific needs in the urban planning process. It can be concluded that current tools, are not readily applicable to support decision making as such. However, if applied cautiously, they can have an indicative role to pinpoint further targeted and in-depth analyses.
Keywords: A1 Journal Article; Engineering Management (ENM) ;
Impact Factor: 8.7
DOI: 10.1016/j.jenvman.2020.110603
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“Economic performance of pyrolysis of mixed plastic waste: Open-loop versus closed-loop recycling”. Larrain M, Van Passel S, Thomassen G, Kresovic U, Alderweireldt N, Moerman E, Billen P, Journal Of Cleaner Production , 122442 (2020). http://doi.org/10.1016/j.jclepro.2020.122442
Abstract: In recent decades new recycling technologies for mixed plastic waste have emerged. In pyrolysis, the polymer chains are thermally broken (pyrolyzed) to obtain hydrocarbon materials of different molecular weights such as naphtha, oil or waxes, whose yields can be controlled by varying the reaction parameters. Naphtha represents a closed-loop recycling process as it is a feedstock for (poly)olefins; while the co-production of waxes, having several applications in e.g. the construction industry, exemplifies an open-loop recycling process. This paper compares the economic performance of the pyrolysis of mixed polyolefin waste in a closed-loop and open-loop scheme, including a probabilistic approach to the most important variables. From an economic perspective, open-loop pyrolysis as presented outperforms closed-loop recycling, due to the high prices of wax. However, the results present a high dispersion caused by the volatility of the prices of crude oil and its derivates. Considering the current oil price projections, our case study analysis showed that for open-loop recycling there is a future probability of almost a 98 % of observing positive results and around 57 % of probability in the case of closed-loop recycling, under the assumptions made. Yet, in a future scenario where decarbonized electricity would decrease oil prices, the probability of a positive outcome reduces to 57 % for the open-loop case and to less than 8 % in the case of closed-loop recycling. To make these pathways attractive to investors, the nameplate capacity should be at least 70 kt/year for open-loop recycling and 115 kt/year for closed-loop recycling. A 120 kt/year plant should operate minimally at 80 % of its capacity for open-loop recycling, while closed-loop recycling would demand running close to maximum capacity. Security of feedstock supply therefore is required.
Keywords: A1 Journal Article; Engineering Management (ENM) ;
Impact Factor: 11.1
DOI: 10.1016/j.jclepro.2020.122442
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“Economic performance of pyrolysis of mixed plastic waste: Open-loop versus closed-loop recycling”. Larrain M, Van Passel S, Thomassen G, Kresovic U, Alderweireldt N, Moerman E, Billen P, Journal Of Cleaner Production , 122442 (2020). http://doi.org/10.1016/j.jclepro.2020.122442
Abstract: In recent decades new recycling technologies for mixed plastic waste have emerged. In pyrolysis, the polymer chains are thermally broken (pyrolyzed) to obtain hydrocarbon materials of different molecular weights such as naphtha, oil or waxes, whose yields can be controlled by varying the reaction parameters. Naphtha represents a closed-loop recycling process as it is a feedstock for (poly)olefins; while the co-production of waxes, having several applications in e.g. the construction industry, exemplifies an open-loop recycling process. This paper compares the economic performance of the pyrolysis of mixed polyolefin waste in a closed-loop and open-loop scheme, including a probabilistic approach to the most important variables. From an economic perspective, open-loop pyrolysis as presented outperforms closed-loop recycling, due to the high prices of wax. However, the results present a high dispersion caused by the volatility of the prices of crude oil and its derivates. Considering the current oil price projections, our case study analysis showed that for open-loop recycling there is a future probability of almost a 98 % of observing positive results and around 57 % of probability in the case of closed-loop recycling, under the assumptions made. Yet, in a future scenario where decarbonized electricity would decrease oil prices, the probability of a positive outcome reduces to 57 % for the open-loop case and to less than 8 % in the case of closed-loop recycling. To make these pathways attractive to investors, the nameplate capacity should be at least 70 kt/year for open-loop recycling and 115 kt/year for closed-loop recycling. A 120 kt/year plant should operate minimally at 80 % of its capacity for open-loop recycling, while closed-loop recycling would demand running close to maximum capacity. Security of feedstock supply therefore is required.
Keywords: A1 Journal Article; Engineering Management (ENM) ;
Impact Factor: 11.1
DOI: 10.1016/j.jclepro.2020.122442
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“Circumventing Wear and Tear of Adaptive Porous Materials”. Canossa S, Ji Z, Wuttke S, Advanced Functional Materials , 1908547 (2020). http://doi.org/10.1002/adfm.201908547
Abstract: The assessment of the architectural stability of molecular porous materials is not yet a common practice, but critical to their understanding and development. The conformational adaptation of porous materials to guest binding and other chemical dynamics poses a risk of architectural damage, leading to performance deterioration during their prolonged usage. The deformation of the framework backbone and the disconnection of building units are driven by chemical, mechanical, and thermal perturbations, and can be quantitatively described by the term connection completeness. Analytical means that can be used to measure this parameter are presented in order to provide a standard, practical protocol for evaluating architectural damage made to framework materials. Preventive and remedial strategies are proposed for enhancing the architectural integrity of frameworks without compromising their functional mechanisms, paving the way to the design of robust yet adaptive materials. In this way, the discussion on architectural stability is initiated, and readers are encouraged to carefully characterize molecular porous materials for a better understanding of their structure-property relationship.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 19
DOI: 10.1002/adfm.201908547
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“Overcoming Crystallinity Limitations of Aluminium Metal-Organic Frameworks by Oxalic Acid Modulated Synthesis”. Canossa S, Gonzalez-Nelson A, Shupletsov L, Carmen Martin M, Van der Veen MA, Chemistry-A European Journal 26, 3564 (2020). http://doi.org/10.1002/chem.201904798
Abstract: A modulated synthesis approach based on the chelating properties of oxalic acid (H2C2O4) is presented as a robust and versatile method to achieve highly crystalline Al‐based metal‐organic frameworks. A comparative study on this method and the already established modulation by hydrofluoric acid was conducted using MIL‐53 as test system. The superior performance of oxalic acid modulation in terms of crystallinity and absence of undesired impurities is explained by assessing the coordination modes of the two modulators and the structural features of the product. The validity of our approach was confirmed for a diverse set of Al‐MOFs, namely X‐MIL‐53 (X=OH, CH3O, Br, NO2), CAU‐10, MIL‐69, and Al(OH)ndc (ndc=1,4‐naphtalenedicarboxylate), highlighting the potential benefits of extending the use of this modulator to other coordination materials.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.3
DOI: 10.1002/chem.201904798
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“A review on learning effects in prospective technology assessment”. Thomassen G, Van Passel S, Dewulf J, Renewable &, Sustainable Energy Reviews 130, 109937 (2020). http://doi.org/10.1016/j.rser.2020.109937
Abstract: Global environmental problems have urged the need for developing sustainable technologies. However, new technologies that enter the market have often higher economic costs and potentially higher environmental impacts than conventional technologies. This can be explained by learning effects: a production process that is performed for the first time runs less smooth than a production process that has been in operation for years. To obtain a fair estimation of the potential of a new technology, learning effects need to be included. A review on the current literature on learning effects was conducted in order to provide guidelines on how to include learning effects in prospective technology assessment. Based on the results of this review, five recommendations have been formulated and an integration of learning effects in the structure of prospective technology assessment has been proposed. These five recommendations include the combined use of learning effects on the component level and on the end product level; the combined use of learning effects on the technical, economic and environmental level; the combined use of extrapolated values and expert estimates; the combined use of learning-by-doing and learning-by-searching effects and; a tier-based method, including quality criteria, to calculate the learning effect. These five complementary strategies could lead to a clearer perspective on the environmental impact and cost structure of the new technology and a fairer comparison base with conventional technologies, potentially resulting in a faster adoption and a shorter time-to-market for sustainable technologies.
Keywords: A1 journal article; Learning effects; Life cycle assessment; Techno-economic assessment; Prospective technology assessment; Learning-by-doing; Learning curve; Progress rate; Experience curve; Engineering Management (ENM) ;
Impact Factor: 15.9
DOI: 10.1016/j.rser.2020.109937
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“Plasma Technology for CO2 Conversion: A Personal Perspective on Prospects and Gaps”. Bogaerts A, Centi G, Frontiers in energy research 8 (2020). http://doi.org/10.3389/fenrg.2020.00111
Abstract: There is increasing interest in plasma technology for CO2 conversion because it can operate at mild conditions and it can store fluctuating renewable electricity into
value-added compounds and renewable fuels. This perspective paper aims to provide a view on the future for non-specialists who want to understand the role of plasma
technology in the new scenario for sustainable and low-carbon energy and chemistry. Thus, it is prepared to give a personal view on future opportunities and challenges. First, we introduce the current state-of-the-art and the potential of plasma-based CO2 conversion. Subsequently, we discuss the challenges to overcome the current limitations and to apply plasma technology on a large scale. The final section discusses the general context and the potential benefits of plasma-based CO2 conversion for our life and the impact on climate change. It also includes a brief analysis on the future scenario for energy and chemical production, and how plasma technology may realize new paths for CO2 utilization.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.4
DOI: 10.3389/fenrg.2020.00111
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“Micelle-directed chiral seeded growth on anisotropic gold nanocrystals”. González-Rubio G, Mosquera J, Kumar V, Pedrazo-Tardajos A, Llombart P, Solís DM, Lobato I, Noya EG, Guerrero-Martínez A, Taboada JM, Obelleiro F, MacDowell LG, Bals S, Liz-Marzán LM, Science 368, 1472 (2020). http://doi.org/10.1126/science.aba0980
Abstract: Surfactant-assisted seeded growth of metal nanoparticles (NPs) can be engineered to produce anisotropic gold nanocrystals with high chiroptical activity through the templating effect of chiral micelles formed in the presence of dissymmetric cosurfactants. Mixed micelles adsorb on gold nanorods, forming quasihelical patterns that direct seeded growth into NPs with pronounced morphological and optical handedness. Sharp chiral wrinkles lead to chiral plasmon modes with high dissymmetry factors (~0.20). Through variation of the dimensions of chiral wrinkles, the chiroptical properties can be tuned within the visible and near-infrared electromagnetic spectrum. The micelle-directed mechanism allows extension to other systems, such as the seeded growth of chiral platinum shells on gold nanorods. This approach provides a reproducible, simple, and scalable method toward the fabrication of NPs with high chiral optical activity.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 56.9
Times cited: 187
DOI: 10.1126/science.aba0980
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“Plasma-Based N2Fixation into NOx: Insights from Modeling toward Optimum Yields and Energy Costs in a Gliding Arc Plasmatron”. Vervloessem E, Aghaei M, Jardali F, Hafezkhiabani N, Bogaerts A, Acs Sustainable Chemistry &, Engineering 8, 9711 (2020). http://doi.org/10.1021/acssuschemeng.0c01815
Abstract: Plasma technology provides a sustainable, fossil-free method for N2 fixation, i.e., the conversion of inert atmospheric N2 into valuable substances, such as NOx or ammonia. In this work, we present a novel gliding arc plasmatron at atmospheric pressure for NOx production at different N2/O2 gas feed ratios, offering a promising NOx yield of 1.5% with an energy cost of 3.6 MJ/mol NOx produced. To explain the underlying mechanisms, we present a chemical kinetics model, validated by experiments, which provides insight into the NOx formation pathways and into the ambivalent role of the vibrational kinetics. This allows us to pinpoint the factors limiting the yield and energy cost, which can help to further improve the process.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 8.4
DOI: 10.1021/acssuschemeng.0c01815
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“Secondary-Phase-Assisted Grain Boundary Migration in CuInSe2”. Li C, Sanli ES, Barragan-Yani D, Stange H, Heinemann M-D, Greiner D, Sigle W, Mainz R, Albe K, Abou-Ras D, van Aken P A, Physical Review Letters 124, 095702 (2020). http://doi.org/10.1103/PhysRevLett.124.095702
Abstract: Significant structural evolution occurs during the deposition of CuInSe2 solar materials when the Cu content increases. We use in situ heating in a scanning transmission electron microscope to directly observe how grain boundaries migrate during heating, causing nondefected grains to consume highly defected grains. Cu substitutes for In in the near grain boundary regions, turning them into a Cu-Se phase topotactic with the CuInSe2 grain interiors. Together with density functional theory and molecular dynamics calculations, we reveal how this Cu-Se phase makes the grain boundaries highly mobile.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 8.6
DOI: 10.1103/PhysRevLett.124.095702
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“YBa2Cu3O7−xfilms with Ba2Y(Nb,Ta)O6nanoinclusions for high-field applications”. Celentano G, Rizzo F, Augieri A, Mancini A, Pinto V, Rufoloni A, Vannozzi A, MacManus-Driscoll JL, Feighan J, Kursumovic A, Meledin A, Mayer J, Van Tendeloo G, Superconductor Science &, Technology 33, 044010 (2020). http://doi.org/10.1088/1361-6668/ab6ee5
Abstract: The structural and transport properties of YBa2Cu3O7−x films grown by pulsed laser deposition with mixed 2.5 mol% Ba2YTaO6 (BYTO) and 2.5 mol% Ba2YNbO6 (BYNO) double-perovskite secondary phases are investigated in an extended film growth rate, R = 0.02–1.8 nm s−1. The effect of R on the film microstructure analyzed by TEM techniques shows an evolution from sparse and straight to denser, thinner and splayed continuous columns, with mixed BYNO + BYTO (BYNTO) composition, as R increases from 0.02 nm s−1 to 1.2 nm s−1. This microstructure results in very efficient flux pinning at 77 K, leading to a remarkable improvement in the critical current density (J c) behaviour, with the maximum pinning force density F p(Max) = 13.5 GN m−3 and the irreversibility field in excess of 11 T. In this range, the magnetic field values at which the F p is maximized varies from 1 T to 5 T, being related to the BYNTO columnar density. The film deposited when R = 0.3 nm s−1 exhibits the best performances over the whole temperature and magnetic field ranges, achieving F p(Max) = 900 GN m−3 at 10 K and 12 T. At higher rates, R > 1.2 nm s−1, BYNTO columns show a meandering nature and are prone to form short nanorods. In addition, in the YBCO film matrix a more disordered structure with a high density of short stacking faults is observed. From the analysis of the F p(H, T) curves it emerges that in films deposited at the high R limit, the vortex pinning is no longer dominated by BYNTO columnar defects, but by a new mechanism showing the typical temperature scaling law. Even though this microstructure produces a limited improvement at 77 K, it exhibits a strong J c improvement at lower temperature with F p = 700 GN m−3 at 10 K, 12 T and 900 GN m−3 at 4.2 K, 18 T.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.6
DOI: 10.1088/1361-6668/ab6ee5
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“Electrochemical Analysis of Speedball-like Polydrug Samples”. de Jong M, Florea A, Daems D, Van Loon J, Samyn N, De Wael K, Analyst (2020). http://doi.org/10.1039/D0AN01097A
Abstract: Increasing global production, trafficking and consumption of drugs of abuse cause an emerging threat to people’s health and safety. Electrochemical approaches have proven to be useful for on-site analysis of drugs of abuse. However, few attention has been focused on the analysis of polydrug samples, despite these samples causing severe health concerns, certainly when stimulants and depressants are combined, as is the case for Speedball, a mixture of cocaine and heroin. In this work, we provide solutions for the selective detection of cocaine (stimulant) in polydrug samples adulterated with heroin and codeine (depressants). The presence of either one of these compounds in cocaine street samples leads to an overlap with the cocaine signal in square-wave voltammetry measurements at unmodified carbon screen-printed electrodes, leading to inconclusive screening results in the field. The provided solutions to this problem consist of two parallel approaches: (i) cathodic pretreatment of the carbon screen-printed electrode surface prior to measurement in both alkaline and neutral conditions; (ii) electropolymerization of orthophenylenediamine on graphene modified carbon screen-printed electrodes prior to measurement in neutral conditions. Both strategies allow simultaneous detection of cocaine and heroin in speedball samples as well as simultaneous detection of cocaine and codeine. Implementing these strategies in portable devices holds great potential for significantly improved accuracy of on-site cocaine screening in polydrug samples.
Keywords: A1 Journal article; Pharmacology. Therapy; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Product development
Impact Factor: 4.2
DOI: 10.1039/D0AN01097A
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“Predicted Hotspot Residues Involved in Allosteric Signal Transmission in Pro-Apoptotic Peptide—Mcl1 Complexes”. Marimuthu P, Razzokov J, Singaravelu K, Bogaerts A, Biomolecules 10, 1114 (2020). http://doi.org/10.3390/biom10081114
Abstract: Mcl1 is a primary member of the Bcl–2 family—anti–apoptotic proteins (AAP)—that is overexpressed in several cancer pathologies. The apoptotic regulation is mediated through the binding of pro-apoptotic peptides (PAPs) (e.g., Bak and Bid) at the canonical hydrophobic binding groove (CBG) of Mcl1. Although all PAPs form amphipathic α-helices, their amino acid sequences vary to different degree. This sequence variation exhibits a central role in the binding partner selectivity towards different AAPs. Thus, constructing a novel peptide or small organic molecule with the ability to mimic the natural regulatory process of PAP is essential to inhibit various AAPs. Previously reported experimental binding free energies (BFEs) were utilized in the current investigation aimed to understand the mechanistic basis of different PAPs targeted to mMcl1. Molecular dynamics (MD) simulations used to estimate BFEs between mMcl1—PAP complexes using Molecular Mechanics-Generalized Born Solvent Accessible (MMGBSA) approach with multiple parameters. Predicted BFE values showed an excellent agreement with the experiment (R2 = 0.92). The van–der Waals (ΔGvdw) and electrostatic (ΔGele) energy terms found to be the main energy components that drive heterodimerization of mMcl1—PAP complexes. Finally, the dynamic network analysis predicted the allosteric signal transmission pathway involves more favorable energy contributing residues. In total, the results obtained from the current investigation may provide valuable insights for the synthesis of a novel peptide or small organic inhibitor targeting Mcl1.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
DOI: 10.3390/biom10081114
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“The optical nanosizer –, quantitative size and shape analysis of individual nanoparticles by high-throughput widefield extinction microscopy”. Payne LM, Albrecht W, Langbein W, Borri P, Nanoscale (2020). http://doi.org/10.1039/D0NR03504A
Abstract: Nanoparticles are widely utilised for a range of applications, from catalysis to medicine, requiring accurate knowledge of their size and shape. Current techniques for particle characterisation are either not very accurate or time consuming and expensive. Here we demonstrate a rapid and quantitative method for particle analysis based on measuring the polarisation-resolved optical extinction cross-section of hundreds of individual nanoparticles using wide-field microscopy, and determining the particle size and shape from the optical properties. We show measurements on three samples consisting of nominally spherical gold nanoparticles of 20 nm and 30 nm diameter, and gold nanorods of 30 nm length and 10 nm diameter. Nanoparticle sizes and shapes in three dimensions are deduced from the measured optical cross-sections at different wavelengths and light polarisation, by solving the inverse problem, using an ellipsoid model of the particle polarisability in the dipole limit. The sensitivity of the method depends on the experimental noise and the choice of wavelengths. We show an uncertainty down to about 1 nm in mean diameter, and 10% in aspect ratio when using two or three color channels, for a noise of about 50 nm<sup>2</sup>in the measured cross-section. The results are in good agreement with transmission electron microscopy, both 2D projection and tomography, of the same sample batches. Owing to its combination of experimental simplicity, ease of access to statistics over many particles, accuracy, and geometrical particle characterisation in 3D, this “optical nanosizer” method has the potential to become the technique of choice for quality control in next-generation particle manufacturing.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 6.7
DOI: 10.1039/D0NR03504A
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“Quantifying Strain and Dislocation Density at Nanocube Interfaces after Assembly and Epitaxy”. Agrawal H, Patra BK, Altantzis T, De Backer A, Garnett EC, Acs Applied Materials &, Interfaces 12, 8788 (2020). http://doi.org/10.1021/acsami.9b17779
Abstract: Nanoparticle self-assembly and epitaxy are utilized extensively to make 1D and 2D structures with complex shapes. High-resolution transmission electron microscopy (HRTEM) has shown that single-crystalline interfaces can form, but little is known about the strain and dislocations at these interfaces. Such information is critically important for applications: drastically reducing
dislocation density was the key breakthrough enabling widespread implementation of light-emitting diodes, while strain engineering has been fundamental to modern high-performance transistors, solar cells, and thermoelectrics. In this work, the interfacial defect and strain formation after selfassembly and room temperature epitaxy of 7 nm Pd nanocubes capped with polyvinylpyrrolidone (PVP) is examined. It is observed that, during ligand removal, the cubes move over large distances on the substrate, leading to both spontaneous self-assembly and epitaxy to form single crystals. Subsequently, atomically resolved images are used to quantify the strain and dislocation density at the epitaxial interfaces between cubes with different lateral and angular misorientations. It is shown that dislocation- and strain-free interfaces form when the nanocubes align parallel to each other. Angular misalignment between adjacent cubes does not necessarily lead to grain boundaries but does cause dislocations, with higher densities associated with larger rotations.
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.9b17779
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“Manganese‐Doping‐Induced Quantum Confinement within Host Perovskite Nanocrystals through Ruddlesden–Popper Defects”. Paul S, Bladt E, Richter AF, Döblinger M, Tong Y, Huang H, Dey A, Bals S, Debnath T, Polavarapu L, Feldmann J, Angewandte Chemie-International Edition 59, 6794 (2020). http://doi.org/10.1002/anie.201914473
Abstract: The concept of doping Mn2+ ions into II–VI semiconductor nanocrystals (NCs) was recently extended to perovskite NCs. To date, most studies on Mn2+ doped NCs focus on enhancing the emission related to the Mn2+ dopant via an energy transfer mechanism. Herein, we found that the doping of Mn2+ ions into CsPbCl3 NCs not only results in a Mn2+‐related orange emission, but also strongly influences the excitonic properties of the host NCs. We observe for the first time that Mn2+ doping leads to the formation of Ruddlesden–Popper (R.P.) defects and thus induces quantum confinement within the host NCs. We find that a slight doping with Mn2+ ions improves the size distribution of the NCs, which results in a prominent excitonic peak. However, with increasing the Mn2+ concentration, the number of R.P. planes increases leading to smaller single‐crystal domains. The thus enhanced confinement and crystal inhomogeneity cause a gradual blue shift and broadening of the excitonic transition, respectively.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 16.6
Times cited: 64
DOI: 10.1002/anie.201914473
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“Reliable Characterization of Organic &, Pharmaceutical Compounds with High Resolution Monochromated EEL Spectroscopy”. Das PP, Guzzinati G, Coll C, Gomez Perez A, Nicolopoulos S, Estrade S, Peiro F, Verbeeck J, Zompra AA, Galanis AS, Polymers 12, 1434 (2020). http://doi.org/10.3390/polym12071434
Abstract: Organic and biological compounds (especially those related to the pharmaceutical industry) have always been of great interest for researchers due to their importance for the development of new drugs to diagnose, cure, treat or prevent disease. As many new API (active pharmaceutical ingredients) and their polymorphs are in nanocrystalline or in amorphous form blended with amorphous polymeric matrix (known as amorphous solid dispersion—ASD), their structural identification and characterization at nm scale with conventional X-Ray/Raman/IR techniques becomes difficult. During any API synthesis/production or in the formulated drug product, impurities must be identified and characterized. Electron energy loss spectroscopy (EELS) at high energy resolution by transmission electron microscope (TEM) is expected to be a promising technique to screen and identify the different (organic) compounds used in a typical pharmaceutical or biological system and to detect any impurities present, if any, during the synthesis or formulation process. In this work, we propose the use of monochromated TEM-EELS, to analyze selected peptides and organic compounds and their polymorphs. In order to validate EELS for fingerprinting (in low loss/optical region) and by further correlation with advanced DFT, simulations were utilized.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.364
Times cited: 6
DOI: 10.3390/polym12071434
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“Berry phase engineering at oxide interfaces”. Groenendijk DJ, Autieri C, van Thiel TC, Brzezicki W, Hortensius JR, Afanasiev D, Gauquelin N, Barone P, van den Bos KHW, van Aert S, Verbeeck J, Filippetti A, Picozzi S, Cuoco M, Caviglia AD, 2, 023404 (2020). http://doi.org/10.1103/PhysRevResearch.2.023404
Abstract: Three-dimensional strontium ruthenate (SrRuO3) is an itinerant ferromagnet that features Weyl points acting as sources of emergent magnetic fields, anomalous Hall conductivity, and unconventional spin dynamics. Integrating SrRuO3 in oxide heterostructures is potentially a novel route to engineer emergent electrodynamics, but its electronic band topology in the two-dimensional limit remains unknown. Here we show that ultrathin SrRuO3 exhibits spin-polarized topologically nontrivial bands at the Fermi energy. Their band anticrossings show an enhanced Berry curvature and act as competing sources of emergent magnetic fields. We control their balance by designing heterostructures with symmetric (SrTiO3/SrRuO3/SrTiO3 and SrIrO3/SrRuO3/SrIrO3) and asymmetric interfaces (SrTiO3/SrRuO3/SrIrO3). Symmetric structures exhibit an interface-tunable single-channel anomalous Hall effect, while ultrathin SrRuO3 embedded in asymmetric structures shows humplike features consistent with multiple Hall contributions. The band topology of two-dimensional SrRuO3 proposed here naturally accounts for these observations and harmonizes a large body of experimental results.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 58
DOI: 10.1103/PhysRevResearch.2.023404
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“Atomic scale analysis of defect clustering and predictions of their concentrations in UO2+x”. Caglak E, Govers K, Lamoen D, Labeau P-E, Verwerft M, Journal Of Nuclear Materials 541, 152403 (2020). http://doi.org/10.1016/j.jnucmat.2020.152403
Abstract: The physical properties of uranium dioxide vary greatly with stoichiometry. Oxidation towards hyperstoichiometric UO2 – UO2+x – might be encountered at various stages of the nuclear fuel cycle if oxidative conditions are met; the impact of stoichiometry changes upon physical properties should therefore be properly assessed to ensure safe and reliable operations. These physical properties are intimately linked to the arrangement of atomic defects in the crystalline structure. The evolution of the defect concentration with environmental parameters – oxygen partial pressure and temperature – were evaluated by means of a point defect model where the reaction energies are derived from atomic-scale simulations. To this end, various configurations and net charge states of oxygen interstitial clusters in UO2 have been calculated. Various methodologies have been tested to determine the optimum cluster configurations and a rigid lattice approach turned out to be the most useful strategy to optimize defect configuration structures. Ultimately, results from the point defect model were discussed and compared to experimental measurements of stoichiometry dependence on oxygen partial pressure and temperature.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.1
DOI: 10.1016/j.jnucmat.2020.152403
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“An Expanded Surface-Enhanced Raman Scattering Tags Library by Combinatorial Encapsulation of Reporter Molecules in Metal Nanoshells”. Rodal-Cedeira S, Vázquez-Arias A, Bodelon G, Skorikov A, Núñez-Sanchez S, La Porta A, Polavarapu L, Bals S, Liz-Marzán LM, Perez-Juste J, Pastoriza-Santos I, Acs Nano (2020). http://doi.org/10.1021/acsnano.0c04368
Abstract: Raman-encoded gold nanoparticles have been widely employed as photostable multifunctional probes for sensing, bioimaging, multiplex diagnostics, and surface-enhanced Raman scattering (SERS)-guided tumor therapy. We report a strategy toward obtaining a particularly large library of Au nanocapsules encoded with Raman codes defined by the combination of different thiol-free Raman reporters, encapsulated at defined molar ratios. The fabrication of SERS tags with tailored size and pre-defined codes is based on the in situ incorporation of Raman reporter molecules inside Au nanocapsules during their formation via Galvanic replacement coupled to seeded growth on Ag NPs. The hole-free closed shell structure of the nanocapsules is confirmed by electron tomography. The unusually wide encoding possibilities of the obtained SERS tags are investigated by means of either wavenumber-based encoding or Raman frequency combined with signal intensity, leading to an outstanding performance as exemplified by 26 and 54 different codes, respectively. We additionally demonstrate that encoded nanocapsules can be readily bioconjugated with antibodies for applications such as SERS-based targeted cell imaging and phenotyping.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 17.1
Times cited: 14
DOI: 10.1021/acsnano.0c04368
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“HAADF-STEM block-scanning strategy for local measurement of strain at the nanoscale”. Prabhakara V, Jannis D, Guzzinati G, Béché, A, Bender H, Verbeeck J, Ultramicroscopy 219, 113099 (2020). http://doi.org/10.1016/j.ultramic.2020.113099
Abstract: Lattice strain measurement of nanoscale semiconductor devices is crucial for the semiconductor industry as strain substantially improves the electrical performance of transistors. High resolution scanning transmission electron microscopy (HR-STEM) imaging is an excellent tool that provides spatial resolution at the atomic scale and strain information by applying Geometric Phase Analysis or image fitting procedures. However, HR-STEM images regularly suffer from scanning distortions and sample drift during image acquisition. In this paper, we propose a new scanning strategy that drastically reduces artefacts due to drift and scanning distortion, along with extending the field of view. It consists of the acquisition of a series of independent small subimages containing an atomic resolution image of the local lattice. All subimages are then analysed individually for strain by fitting a nonlinear model to the lattice images. The method allows flexible tuning of spatial resolution and the field of view within the limits of the dynamic range of the scan engine while maintaining atomic resolution sampling within the subimages. The obtained experimental strain maps are quantitatively benchmarked against the Bessel diffraction technique. We demonstrate that the proposed scanning strategy approaches the performance of the diffraction technique while having the advantage that it does not require specialized diffraction cameras.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.2
Times cited: 4
DOI: 10.1016/j.ultramic.2020.113099
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“Fast versus conventional HAADF-STEM tomography of nanoparticles: advantages and challenges”. Vanrompay H, Skorikov A, Bladt E, Béché, A, Freitag B, Verbeeck J, Bals S, Ultramicroscopy 221, 113191 (2021). http://doi.org/10.1016/j.ultramic.2020.113191
Abstract: HAADF-STEM tomography is a widely used experimental technique for analyzing nanometer-scale crystalline structures of a large variety of materials in three dimensions. Unfortunately, the acquisition of conventional HAADF-STEM tilt series can easily take up one hour or more, depending on the complexity of the experiment. It is therefore far from straightforward to investigate samples that do not withstand long acquisition or to acquire large amounts of tilt series during a single TEM experiment. The latter would lead to the ability to obtain statistically meaningful 3D data, or to perform in situ 3D characterizations with a much shorter time resolution. Various HAADF-STEM acquisition strategies have been proposed to accelerate the tomographic acquisition and reduce the required electron dose. These methods include tilting the holder continuously while acquiring a projection “movie” and a hybrid, incremental, methodology which combines the benefits of the conventional and continuous technique. However, until now an experimental evaluation has been lacking. In this paper, the different acquisition strategies will be experimentally compared in terms of speed, resolution and electron dose. This evaluation will be performed based on experimental tilt series acquired for various metallic nanoparticles with different shapes and sizes. We discuss the data processing involved with the fast HAADF-STEM tilt series and provide a general guideline when which acquisition strategy should be preferentially used.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 15
DOI: 10.1016/j.ultramic.2020.113191
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“Plasma-Catalytic Ammonia Synthesis beyond the Equilibrium Limit”. Mehta P, Barboun PM, Engelmann Y, Go DB, Bogaerts A, Schneider WF, Hicks JC, Acs Catalysis 10, 6726 (2020). http://doi.org/10.1021/acscatal.0c00684
Abstract: We explore the consequences of nonthermal plasma-activation on product yields in catalytic ammonia synthesis, a reaction that is equilibrium-limited at elevated temperatures. We employ a minimal microkinetic model that incorporates the influence of plasma-activation on N2 dissociation rates to predict NH3 yields into and across the equilibrium-limited regime. NH3 yields are predicted to exceed bulk thermodynamic equilibrium limits on materials that are thermal-rate-limited by N2 dissociation. In all cases, yields revert to bulk equilibrium at temperatures at which thermal reaction rates exceed plasma-activated ones. Beyond-equilibrium NH3 yields are observed in a packed bed dielectric barrier discharge reactor and exhibit sensitivity to catalytic material choice in a way consistent with model predictions. The approach and results highlight the opportunity to exploit synergies between nonthermal plasmas and catalysts to affect transformations at conditions inaccessible through thermal routes.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 12.9
DOI: 10.1021/acscatal.0c00684
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