• The Hague, Netherlands
Recent publications
Salt crystallization is a major cause of weathering of mortars, including plasters and renders. In the last decade, the use of mixed-in salt crystallization inhibitors in mortars has been proposed as a solution to improve the durability of this material with respect to salt decay. Laboratory characterization and accelerated weathering tests have shown encouraging results. However, data on the long-term behaviour of these mortars when applied on-site were missing until now . In this research the durability with respect to salt decay of a lime-based plaster and a salt accumulating plaster has been assessed. These plasters, with and without sodium ferrocyanide, a well-known inhibitor of sodium chloride crystallization, have been applied to an interior brick masonry wall with a high salt (sodium chloride) and moisture load and monitored for a period of 4 years. Monitoring included visual and photographic observations of the damage as well as measurements of the moisture and salt content and distribution, both in the wall and in the plaster. Moreover, the content and distribution of the inhibitor in the plaster after 4 year exposure was measured, to gain insight into the dissolution and transport of the inhibitor. The results of the research clearly show that the inhibitor is able to significantly reduce the occurrence of salt-induced decay in the lime-based plaster, in comparison to the plaster without inhibitor. No conclusions can be drawn in the case of the salt accumulating plaster, as no decay has developed yet in this case. Two issues related to leaching of the inhibitor and surface discolouration have emerged. These are discussed and possible solutions are proposed.
Cargo ships navigating global waters are required to be sufficiently safe and compliant with international treaties. Governmental inspectorates currently assess in a rule-based manner whether a ship is potentially noncompliant and thus needs inspection. One of the dominant ship characteristics in this assessment is the ‘colour’ of the flag a ship is flying, where countries with a positive reputation have a so-called ‘white flag’. The colour of a flag may disproportionately influence the inspector, causing more frequent and stricter inspections of ships flying a non-white flag, resulting in confirmation bias in historical inspection data. In this paper, we propose an automated approach for the assessment of ship noncompliance, realising two important contributions. First, we reduce confirmation bias by using fair classifiers that decorrelate the flag from the risk classification returned by the model. Second, we extract mobility patterns from a cargo ship network, allowing us to derive meaningful features for ship classification. Crucially, these features model the behaviour of a ship, rather than its static properties. Our approach shows both a higher overall prediction performance and improved fairness with respect to the flag. Ultimately, this work enables inspectorates to better target noncompliant ships, thereby improving overall maritime safety and environmental protection.
Excessive thermal water volumes have been extracted from porous sedimentary rocks in the Hungarian part of the Pannonian Basin. Thermal water production in Hungary increased significantly from the early 1970s. Regional-scale exploitation of geothermal reservoirs without re-injection resulted in basin-scale pressure drop in the Upper Pannonian (Upper Miocene) sediments, leading to compaction. This compaction resulted in ground subsidence primarily through poro-elastic coupling. We investigated surface deformation at the Szentes geothermal filed, SE Hungary, where the largest pressure decline occurred. Subsequently, hydraulic head recovery in the western part of the geothermal reservoir was initiated in the mid-1990s. We obtained data from the European Space Agency’s Envisat satellites to estimate the ground motions for the period of November 2002–December 2006. We applied inverse geomechanical modeling to estimate reservoir properties and processes. We constrained the model parameters using the Ensemble Smoother with Multiple Data Assimilation, which allowed us to incorporate large amounts of surface movement observations in a computationally efficient way. Ground movements together with the modeling results show that uplift of the Szentes geothermal field occurred during the observation period. Since no injection wells were operated at Szentes before 2018, and production temperatures remained relatively constant through the entire production period, we explain ground uplift with pore pressure increase due to natural recharge. The estimated decompaction coefficients of the reservoir system characterizing the elastic behavior of the Szentes geothermal reservoir varies between ~ 0.2 × 10 –9 and 2 × 10 –9 Pa ⁻¹ . Compaction coefficients of the reservoir system corresponding to the earlier depressurization period, from ~ 1970 to the mid-1990s, may be significantly larger due to the potential inelastic behavior and permanent compaction of clay-rich aquitards. The improved parametrization enables better forecasting of the reservoir behavior and facilitates the assessment of future subsidence scenarios that are helpful for the establishment of a sustainable production scheme.
The pivotal role of nitrogen to achieve environmental sustainable development goals and transform our food system is recognized in an ambitious nitrogen waste reduction target in the Farm to Fork Strategy of the European Commission. But is this a realistic objective and if so, what are the pathways that lead to success? To answer these questions, we first established, as a baseline, an updated food system nitrogen budget for the EU for the year 2015. The EU used 20 Tg of virgin (new) N to deliver 2.5 Tg N in food and 1.2 Tg N in fibres to consumers, yielding a food-system nitrogen use efficiency (NUE) of 18%. We then built a simple model to combine intervention options that (a) increase farm level nitrogen use efficiencies, (b) reduce food waste increase recycling of waste and improve waste treatment, or (c) achieve a dietary shift towards healthier dietary patterns. The largest potential to increase N efficiency of the current agro-food system was found to lie in the livestock sector. From 144 possible combinations of intervention options analysed, we found that 12 combinations of interventions would reduce nitrogen losses by about 50%, 11 involving diet change. We further carried out an assessment of the societal appreciation of combinations of interventions considering private and public costs of the intervention measures, public benefit through effects on health and increased biodiversity of ecosystems, and public costs for overcoming socio-cultural barriers. Results show that a combination of moderate intervention options achieve halving of N losses at lowest societal costs. We conclude that systemic approaches are paramount to achieve deep nitrogen reduction targets and diet change appears to be an essential condition for success.
Objectives This study aims to investigate across subgroups of healthcare workers (1) the changes in psychosocial working conditions and emotional exhaustion during the pandemic compared with the situation before, and (2) the impact of different stages of the COVID-19 pandemic in terms of hospital pressure on psychosocial working conditions and emotional exhaustion. Methods Five questionnaire measurements during 2 years from 1915 healthcare workers in the longitudinal study ‘the Netherlands Working Conditions Survey-COVID-19’ were used. At each measurement, three subgroups were defined: working with patients with COVID-19, working with other patients and not working with patients. For each measurement, hospital pressure was determined by number of hospitalisations per day. Linear mixed models were fitted to analyse differences across subgroups of healthcare workers. Results During COVID-19, psychosocial working conditions deteriorated among healthcare workers working with patients, in particular with patients with COVID-19, compared with healthcare workers not working with patients after correcting for the situation before COVID-19. No changes were observed for emotional exhaustion in any of the subgroups. An increasing hospital pressure improved job autonomy and reduced emotional demands among healthcare workers in COVID-19 wards, but had no influence on other psychosocial working conditions and emotional exhaustion. Conclusion Psychosocial working conditions deteriorated for healthcare workers working with (COVID-19) patients during the pandemic, while emotional exhaustion did not change among all groups of healthcare workers.
Much of recent progress in geophysics can be attributed to the adaptation of heterogeneous high-performance computing architectures. It is projected that the next major leap in many areas of science, and hence hopefully in geophysics too, will be due to the emergence of quantum computers. Finding a right combination of hardware, algorithms and a use-case, however, proves to be a very challenging task – especially when looking for a relevant application that scales efficiently on a quantum computer and is difficult to solve using classical means. We show that maximizing stack-power for residual statics correction, an NP-hard combinatorial optimization problem, appears to naturally fit a particular type of quantum computing known as quantum annealing. We express the underlying objective function as a quadratic unconstrained binary optimization, which is a quantum-native formulation of the problem. We choose some solution space, and define a proper encoding to translate the problem-variables into qubit states. We show that these choices can have a significant impact on the maximum problem size that can fit on the quantum annealer and on the fidelity of the final result. To improve the latter, we embed the quantum optimization step in a hybrid classical-quantum workflow, which aims to increase the frequency of finding the global, rather than some local, optimum of the objective function. Lastly, we show that a generic, black-box, hybrid classical-quantum solver could also be used to solve stack-power maximization problems proximal to industrial relevance, and capable to surpassing deterministic solvers prone to cycle-skipping. A custom-build workflow capable of solving larger problems with an even higher robustness and greater control of the user appears to be within reach in the very near future.
In the past years, the use of liquid additives as bitumen modifiers has increased to tailor the rheology of bitumen for a wide range of applications. Their chemical composition and mutual interaction result in specific phase morphologies in the binders. Hence, there is a need to evaluate the phase morphology of complex binders and the impact of additives on their physical properties. The RILEM Technical Committee 272-PIM 'Phase and Interphase behaviour of innovative bituminous Materials', Task Group TG1 assessed the phase and interphase properties of bituminous binders. Some preliminary results are presented on blends using three liquid additives and a neat 35/50 bitumen. The goal of formulating the blends was to achieve similar consistency of a pen grade 70/100 bitumen at the original state and to evaluate the binders at both original and after aging. Physical properties were evaluated through rheological characterisation using a dynamic shear rheometer (DSR) in a wide range of conditions. The phase morphology was assessed using atomic force microscopy (AFM). Differential scanning calorimetry (DSC) was also used for the characterisation of the thermal behaviour of the binders. While conventional properties, as obtained from the routine binder testing methods, hardly distinguish between blends, the cross-over temperature, derived from DSR measurements, enabled to dictate the impact of liquid additives on the physical properties of bituminous binders at intermediate temperature. AFM confirmed a difference in phase morphology between the blends, whereas some binders displayed new phases at original and aged conditions. Glass transition, as determined by DSC, also showed a difference in the low-temperature domain that may be explained with the difference in phase morphology. Overall, an in-depth understanding of microstructure morphology and glass transition behaviour of complex binders can assist in designing future specifications to distinguish durable bituminous materials better.
We perform statistical analyses on spatiotemporal patterns in the magnitude distribution of induced earthquakes in the Groningen natural gas field. The seismic catalogue contains 336 earthquakes with (local) magnitudes above 1.45, observed in the period between 1 January 1995 and 1 January 2022. An exploratory moving-window analysis of maximum-likelihood b-values in both time and space does not reveal any significant variation in time, but does reveal a spatial variation that exceeds the 0.05 significance level. In search for improved understanding of the observed spatial variations in physical terms we test five physical reservoir properties as possible b-value predictors. The predictors include two static (spatial, time-independent) properties: the reservoir layer thickness, and the topographic gradient (a measure of the degree of faulting intensity in the reservoir); and three dynamic (spatiotemporal, time-dependent) properties: the pressure drop due to gas extraction, the resulting reservoir compaction, and a measure for the resulting induced stress. The latter property is the one that is currently used in the seismic source models that feed into the state-of-the-art hazard and risk assessment. We assess the predictive capabilities of the five properties by statistical evaluation of both moving window analysis, and maximum-likelihood parameter estimation for a number of simple functional forms that express the b-value as a function of the predictor. We find significant linear trends of the b-value for both topographic gradient and induced stress, but even more pronouncedly for reservoir thickness. Also for the moving window analysis and the step function fit, the reservoir thickness provides the most significant results. We conclude that reservoir thickness is a strong predictor for spatial b-value variations in the Groningen field. We propose to develop a forecasting model for Groningen magnitude distributions conditioned on reservoir thickness, to be used alongside, or as a replacement, for the current models conditioned on induced stress.
A miniaturized planar Yagi-Uda antenna for integration with PicoSats or other SmallSat missions is proposed. Miniaturization techniques, such as meandering and 1-D artificial dielectric concepts to reduce the guided wavelength, are employed to overcome space constraints imposed by the SmallSat footprint while still maintaining good performance for the FR-4 antenna. Simulations and measurements have been carried out on the Unicorn-2 PicoSat chassis from Alba Orbital and are in good agreement. Also, antenna dimensions have been reduced between 15% and 66% when compared to a more conventional planar Yagi-Uda antenna working at the same frequency. This compactness allows for simple integration with the deployable solar panel array of the Unicorn-2 PicoSat spacecraft. Full end-fire radiation is achieved and peak gain values are about 5 dBi for the antenna when fully integrated on the satellite chassis, offering an attractive solution for downlink connectivity. This compact antenna design can also be used within an array for beam steering or integrated within the solar cell modules of other PicoSats, CubeSats and SmallSats. Applications include Earth observation, remote sensing, as well as SmallSat to ground station communications. The planar Yagi-Uda antenna may also be useful wherever end-fire radiation is required from a compact antenna structure.
Dealing with heterogeneous plastic waste – i.e., high polymer heterogeneity, additives, and contaminants – and lowering greenhouse gas (GHG) emissions from plastic production requires integrated solutions. Here, we quantified current and future GHG footprints of direct chemical conversion of heterogeneous post-consumer plastic waste feedstock to olefins, a base material for plastics. The net GHG footprint of this recycling system is −0.04 kg CO2-eq./kg waste feedstock treated, including credits from avoided production of virgin olefins, electricity, heat, and credits for the partial biogenic content of the waste feedstock. Comparing chemical recycling of this feedstock to incineration with energy recovery presents GHG benefits of 0.82 kg CO2-eq./kg waste feedstock treated. These benefits were found to increase to 1.37 kg CO2-eq./kg waste feedstock treated for year 2030 when including (i) decarbonization of steam and electricity production and (ii) process optimizations to increase olefin yield through carbon capture and utilization and conversion of side-products.
The threat of attacks using chemical, biological, radiological, or nuclear means (CBRN) describe some of the most extreme possible events in a scenario of conflict. This chapter focuses on chemical (C) threats, where chemical agents are intended to cause a toxic effect on human organisms and where our definition of toxicity excludes those related to radiation exposure and/or the actions of pathogens. We define chemical agents as compounds that may exist in any physical state (e.g., solid, liquid, aerosol, vapour, gas).
Background Healthcare workers are at risk to develop mental health problems and to experience adverse psychosocial working conditions during the COVID-19 pandemic. This study aims to investigate across subgroups of healthcare workers i) differences in psychosocial working conditions and emotional exhaustion, ii) changes in psychosocial working conditions and emotional exhaustion during the pandemic compared to the situation before, and iii) impact of different stages of the COVID-19 pandemic in terms of hospital pressure on psychosocial working conditions and emotional exhaustion. Methods Data on psychosocial working conditions and emotional exhaustion of five measurements from 1,915 healthcare workers participating in the longitudinal study ‘the Netherlands Working Conditions Survey- COVID-19’ were used. Three subgroups were defined: working with COVID-19 patients, working with other patients, and not working with patients. For each measurement, hospital pressure was determined. Linear mixed models were fitted to analyze the differences across subgroups of healthcare workers. Results Healthcare workers working with patients, in particular COVID-19 patients, had more unfavorable psychosocial working conditions than those not working with patients. Psychosocial working conditions deteriorated among those working with patients compared to pre-COVID-19, but no changes were found for emotional exhaustion. An increasing hospital pressure resulted in improved job autonomy and emotional demands among healthcare workers working with COVID-19 patients, but did not result in differences in other working conditions and emotional exhaustion. Conclusions Psychosocial working conditions deteriorated for healthcare workers working with (COVID-19) patients during the pandemic compared to the situation before the pandemic, while emotional exhaustion did not change in these subgroups. This shows the importance of interventions to improve working conditions of healthcare workers. Key messages
Inleiding: In de NCJ-richtlijn Overgewicht (2012) staat dat het gemeten lichaamsgewicht gecorrigeerd moet worden met 400 gram als 4‑ tot 8‑jarigen gewogen worden met hun kleding aan. Aangezien het niet duidelijk is waar deze correctiefactor op gebaseerd is, had dit onderzoek als doel om het gemiddelde kledinggewicht tijdens het periodiek geneeskundig onderzoek (PGO) groep 2 te bepalen. Methode: Tijdens het PGO groep 2 werd het gewicht van de gedragen kleding gemeten. Daarnaast werden geslacht, lengte, gewicht en buitentemperatuur geregistreerd. Resultaten: Er werden 52 kinderen geïncludeerd. Het gemiddelde kledinggewicht was 392 ± 108,6 (spreiding 194–658) gram. Kledinggewicht was afhankelijk van geslacht; jongens droegen gemiddeld 137,6 gram (p < 0,001) zwaardere kleding. Er was een positieve associatie met body mass index (BMI) en gewicht. Er was geen verband tussen kledinggewicht en lengte of buitentemperatuur. Conclusie: De correctiefactor voor kledinggewicht zoals beschreven in de NCJ-richtlijn Overgewicht lijkt, in ieder geval voor 4‑ tot 8‑jarigen, correct te zijn. Aangezien kledinggewicht afhankelijk is van geslacht, gewicht en BMI, dient daar in de praktijk rekening mee gehouden te worden. Er is geen verband met lengte of buitentemperatuur, hoewel dit laatste kan komen doordat de dataverzameling alleen in de wintermaanden plaatsvond.
Objectives Within the chemical legislation, REACH was implemented in order to improve safe working conditions with hazardous substances. Literature and real-life experiences by those concerned have shown that there are still gaps with a need for improved risk communication. This study elaborated on how information provided by REACH is understood and acted on by down- and upstream users, and how it can be further improved. Methods An extensive literature study including 21 studies and 13 tools was carried out. The outcomes were discussed and further supplemented by means of 18 interviews concerning 37 internal safety and REACH documents to build six different use cases representing different Dutch downstream companies. For the upstream perspective also 2 sector organizations and 2 registrants were interviewed. Three online workshops were organized in order to share insights and gather input on international recognition, potential suggestions and further recommendations with 30 participants from nine different EU countries. Results Although the methods to collect the data differed between the different stages of the study, the general results from all three stages elucidated similar themes in the data and each of the stages used the results from the previous stage as a starting point. Recurring themes concerned the (i) complexity of documents, (ii) deficiencies as experienced by SMEs in REACH, (iii) feedback and responsibilities in the supply chain, and (iv) the cooperation between REACH and OSH. Discussion The study at hand revealed that even though there are currently several activities to improve communication on safe-use of chemicals, communication on safe-use in the scope of REACH should be improved. This includes e.g. the future involvement of actual end-users in activities and development related to communication of safe-use information in the scope of REACH including feedback, less complicated and complex documents and clear communication concerning legislations and updates of documents. Furthermore, the issues recognized in the Netherlands are mostly also recognized by international workshop participants, thereby indicating international benefits in various areas by means of improved communication. Conclusions The study confirmed that many of our generic conclusions were already part of the shared knowledge in the REACH community, but that it is very valuable that this knowledge has been explicated, validated and reported in a structured way in the present project. Besides uncovering some crucial aspects that offer potential improvements regarding risk communication, this study offers possible solutions and next steps to be taken.
Background HIV treatment prescription is a complex process. Clinical decision support systems (CDSS) are a category of health information technologies that can assist clinicians to choose optimal treatments based on clinical trials and expert knowledge. The usability of some CDSSs for HIV treatment would be significantly improved by using the knowledge obtained by treating other patients. This knowledge, however, is mainly contained in patient records, whose usage is restricted due to privacy and confidentiality constraints. Methods A treatment effectiveness measure, containing valuable information for HIV treatment prescription, was defined and a method to extract this measure from patient records was developed. This method uses an advanced cryptographic technology, known as secure Multiparty Computation (henceforth referred to as MPC), to preserve the privacy of the patient records and the confidentiality of the clinicians’ decisions. Findings Our solution enables to compute an effectiveness measure of an HIV treatment, the average time-to-treatment-failure, while preserving privacy. Experimental results show that our solution, although at proof-of-concept stage, has good efficiency and provides a result to a query within 24 min for a dataset of realistic size. Interpretation This paper presents a novel and efficient approach HIV clinical decision support systems, that harnesses the potential and insights acquired from treatment data, while preserving the privacy of patient records and the confidentiality of clinician decisions.
Wireless IoT networks have seen an unprecedented rise in number of devices, heterogeneity and emerging use cases which led to diverse throughput, reliability and latency (Quality of Service) requirements. Fulfilling these diverse requirements in a rapidly changing and dynamic wireless environment is a complex and challenging task. On top of including new technologies and wireless standards, one solution is to deploy cross-layer Design (CLD) and multiple Radio Access Technologies (Multi-RAT) to develop scalable QoS-aware IoT networks. However, the complexity of such solutions is high as it involves complex inter-layer interactions and dependencies and inter-application dependencies in multi-RAT networks. Moreover, the wireless environment is very dynamic, so having an optimal constellation of parameters is a challenging task. In this paper, we address the possibilities of using Artificial Intelligence (AI) and Machine Learning (ML) to address these high dimensional and dynamic problems. Based on our findings, we have proposed a distributed network management framework employing AI & ML for studying inter-layer dependencies and developing cross-layer design, traffic classification and traffic prediction at the edge devices for reliable QoS in multi-RAT IoT networks. A thorough discussion on future directions and emerging challenges related to our proposed framework has also been provided for further research in this field.
The main idea behind lattice sieving algorithms is to reduce a sufficiently large number of lattice vectors with each other so that a set of short enough vectors is obtained. It is therefore natural to study vectors which cannot be reduced. In this work we give a concrete definition of an irreducible vector and study the properties of the set of all such vectors. We show that the set of irreducible vectors is a subset of the set of Voronoi relevant vectors and study its properties. For extremal lattices this set may contain as many as 2n\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$2^n$$\end{document} vectors, which leads us to define the notion of a complete system of irreducible vectors, whose size can be upper-bounded by the kissing number. One of our main results shows that modified heuristic sieving algorithms heuristically approximate such a set (modulo sign). We provide experiments in low dimensions which support this theory. Finally we give some applications of this set in the study of lattice problems such as SVP, SIVP and CVPP. The introduced notions, as well as various results derived along the way, may provide further insights into lattice algorithms and motivate new research into understanding these algorithms better.
Background We previously showed that whole-grain wheat (WGW) consumption had beneficial effects on liver fat accumulation, as compared to refined wheat (RW). The mechanisms underlying these effects remain unclear. Objective In this study, we investigated the effects of WGW vs. RW consumption on plasma metabolite levels to explore potential underlying mechanisms of the preventive effect of WGW consumption on liver fat accumulation. Methods Targeted metabolomics of plasma obtained from a concluded 12-week double-blind, randomized controlled trial was performed. Fifty overweight or obese men and women aged 45–70 years with mildly elevated levels of plasma cholesterol were randomized to either 98 g/d of WGW or RW products. Before and after the intervention, a total of 89 fasting plasma metabolite concentrations including acylcarnitines, trimethylamine-N-oxide (TMAO), choline, betaine, bile acids, and signaling lipids were quantified by UPLC-MS/MS. Intrahepatic triglycerides (IHTG) were quantified by ¹ H-MRS, and multiple liver markers, including circulating levels of β-hydroxybutyrate, alanine transaminase (ALT), aspartate transaminase (AST), γ-glutamyltransferase (γ-GT), serum amyloid A (SAA), and C-reactive protein, were assessed. Results The WGW intervention increased plasma concentrations of four out of 52 signaling lipids—lysophosphatidic acid C18:2, lysophosphatidylethanolamine C18:1 and C18:2, and platelet-activating factor C18:2—and decreased concentrations of the signaling lipid lysophosphatidylglycerol C20:3 as compared to RW intervention, although these results were no longer statistically significant after false discovery rate (FDR) correction. Plasma concentrations of the other metabolites that we quantified were not affected by WGW or RW intervention. Changes in the above-mentioned metabolites were not correlated to change in IHTG upon the intervention. Conclusion Plasma acylcarnitines, bile acids, and signaling lipids were not robustly affected by the WGW or RW interventions, which makes them less likely candidates to be directly involved in the mechanisms that underlie the protective effect of WGW consumption or detrimental effect of RW consumption on liver fat accumulation. Clinical trial registration [ ], identifier [NCT02385149].
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1,772 members
Marianne De Wolff
  • Expertise Group for Child Health
Aswin Menke
  • Expertise Group for Metabolic Health
Armand Paauw
  • Expertise Group for CBRN Protection
Anna van Buerenplein 1, NL-2595, The Hague, Netherlands