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Gielis curves and surfaces can describe a wide range of natural shapes and they have been used in various studies in biology and physics as descriptive tool. This has stimulated the generalization of widely used computational methods. Here we show that proper normalization of the Levenberg-Marquardt algorithm allows for efficient and robust reconstruction of Gielis curves, including self-intersecting and asymmetric curves, without increasing the overall complexity of the algorithm. Then, we show how complex curves of k-type can be constructed and how solutions to the Dirichlet problem for the Laplace equation on these complex domains can be derived using a semi-Fourier method. In all three methods, descriptive and computational power and efficiency is obtained in a surprisingly simple way. Formal Correction: see "host".

This thesis compares sickness absence in Belgium, West-Germany and The Netherlands. The comparison was restricted to sickness absence in greatly similar groups of private sector employees in these countries (observation period 1980, 1981). For a more recent observation period (1983-1987) rates are adapted and calculated from benefits administrations. Most sickness absence investigations regard the effects of personal and organizational factors, which operate within a given national context. After having assessed the weight of some of these factors, the further inquiry has been focussed on macro-level differences. Macro-level differences taken together with some related organization-level differences show to be highly relevant for our understanding of the international differences observed in sickness absence rates.

In most layered additive manufacturing processes, a tool solidifies or deposits material while following pre-planned trajectories to form solid beads. Many interesting problems arise in this context, among which one concerns the planning of trajectories for filling a planar shape as densely as possible. This is the problem we tackle in the present paper. Recent works have shown that allowing the bead width to vary along the trajectories helps increase the filling density. We present a novel technique that, given a deposition width range, constructs a set of closed beads whose width varies within the prescribed range and fill the input shape. The technique outperforms the state of the art in important metrics: filling density (while still guaranteeing the absence of bead overlap) and trajectories smoothness. We give a detailed geometric description of our algorithm, explore its behavior on example inputs and provide a statistical comparison with the state of the art. We show that it is possible to obtain high quality fabricated layers on commodity FDM printers.

International audience; We previously presented a systematic optics-based canonical approach to test material-lighting interactions in their full natural ecology, combining canonical material and lighting modes. Analyzing the power of the spherical harmonics components of the lighting allowed us to predict the lighting effects on material perception for generic natural illumination environments. To further understand how material properties can be brought out or communicated visually, in the current study, we tested whether and how light map orientation and shape affect these interactions in a rating experiment: For combinations of four materials, three shapes, and three light maps, we rotated the light maps in 15 different configurations. For the velvety objects, there were main and interaction effects of lighting and light map orientation. The velvety ratings decreased when the main light source was coming from the back of the objects. For the specular objects, there were main and interaction effects of lighting and shape. The specular ratings increased when the environment in the specular reflections was clearly visible in the stimuli. For the glittery objects, there were main and interaction effects of shape and light map orientation. The glittery ratings correlated with the coverage of the glitter reflections as the shape and light map orientation varied. For the matte objects, results were robust across all conditions. Last, we propose combining the canonical modes approach with so-called importance maps to analyze the appearance features of the proximal stimulus, the image, in contradistinction to the physical parameters as an approach for optimization of material communication.

Industrial symbiosis involves creating integrated cycles of by-products and waste between networks of industrial actors in order to maximize economic value, while at the same time minimizing environmental strain. In such a network, the global environmental strain is no longer equal to the sum of the environmental strain of the individual actors, but it is dependent on how well the network performs as a whole. The development of methods to understand, manage or optimize such networks remains an open issue. In this paper we put forward a simulation model of by-product flow between industrial actors. The goal is to introduce a method for modelling symbiotic exchanges from a macro perspective. The model takes into account the effect of two main mechanisms on a multi-objective optimization of symbiotic processes. First it allows us to study the effect of geographical properties of the economic system, said differently, where actors are divided in space. Second, it allows us to study the effect of clustering complementary actors together as a function of distance, by means of a spatial correlation between the actors' by-products. Our simulations unveil patterns that are relevant for macro-level policy. First, our results show that the geographical properties are an important factor for the macro performance of symbiotic processes. Second, spatial correlations, which can be interpreted as planned clusters such as Eco-industrial parks, can lead to a very effective macro performance, but only if these are strictly implemented. Finally, we provide a proof of concept by comparing the model to real world data from the European Pollutant Release and Transfer Register database using georeferencing of the companies in the dataset. This work opens up research opportunities in interactive data-driven models and platforms to support real-world implementation of industrial symbiosis., Comment: 23 pages, 9 figures, 2 tables

The thesis discussed several strategies that may contribute to further CVD risk reduction in the future. We described two novel lipid-lowering strategies, we unraveled (part of) the etiology of the cardiovascular safety issues of TKIs that are used for the treatment of CML, and we investigated the dose effects of PFOA on lipoprotein metabolism. Looking forward, we developed a novel mouse model that can be used for the study of diabetic macrovascular complications, and we evaluated the potential of OSM as novel target in CVD.

International audience; Photographers and lighting designers set up lighting environments that best depict objects and human figures to convey key aspects of the visual appearance of various materials, following rules drawn from experience. Understanding which lighting environment is best adapted to convey which key aspects of materials is an important question in the field of human vision. The endless range of natural materials and lighting environments poses a major problem in this respect. Here we present a systematic approach to make this problem tractable for lighting–material interactions, using optics-based models, composed of canonical lighting and material modes. In two psychophysical experiments, different groupsof inexperienced observers judged the material qualities of the objects depicted in the stimulus images. In the first experiment, we took photographs of real objects as stimuli under canonical lightings. In a second experiment, we selected three generic natural lighting environments on the basis of their predicted lighting effects and made computerrenderings of the objects. The selected natural lighting environments have characteristics similar to the canonical lightings, as computed using a spherical harmonic analysis. Results from the two experiments correlate strongly, showing (a) how canonical material and lighting modes associate with perceived material qualities; and (b) which lighting is best adapted to evoke perceived material qualities, such as softness, smoothness, and glossiness. Our results demonstrate that a system of canonical modes spanning the natural range of lighting and materials provides a good basis to study lighting–material interactions in their full natural ecology

Product designers extensively use sketches to create and communicate 3D shapes and thus form an ideal audience for sketch-based modeling, non-photorealistic rendering and sketch filtering. However, sketching requires significant expertise and time, making design sketches a scarce resource for the research community. We introduce OpenSketch , a dataset of product design sketches aimed at offering a rich source of information for a variety of computer-aided design tasks. OpenSketch contains more than 400 sketches representing 12 man-made objects drawn by 7 to 15 product designers of varying expertise. We provided participants with front, side and top views of these objects, and instructed them to draw from two novel perspective viewpoints. This drawing task forces designers to construct the shape from their mental vision rather than directly copy what they see. They achieve this task by employing a variety of sketching techniques and methods not observed in prior datasets. Together with industrial design teachers, we distilled a taxonomy of line types and used it to label each stroke of the 214 sketches drawn from one of the two viewpoints. While some of these lines have long been known in computer graphics, others remain to be reproduced algorithmically or exploited for shape inference. In addition, we also asked participants to produce clean presentation drawings from each of their sketches, resulting in aligned pairs of drawings of different styles. Finally, we registered each sketch to its reference 3D model by annotating sparse correspondences. We provide an analysis of our annotated sketches, which reveals systematic drawing strategies over time and shapes, as well as a positive correlation between presence of construction lines and accuracy. Our sketches, in combination with provided annotations, form challenging benchmarks for existing algorithms as well as a great source of inspiration for future developments. We illustrate the versatility of our data by using it to test a 3D reconstruction deep network trained on synthetic drawings, as well as to train a filtering network to convert concept sketches into presentation drawings. We distribute our dataset under the Creative Commons CC0 license: https://ns.inria.fr/d3/OpenSketch.

Een taalontwikkelingsstoornis of TOS is waarschijnlijk de meest voorkomende ontwikkelingsstoornis en komt voor bij ca 7% van de kinderen. Een stoornis in de taalontwikkeling is een ernstige belemmering voor een optimale ontplooiing van een kind en daarmee voor zijn of haar toekomstige plek in de samenleving. Toch worden veel kinderen met TOS pas laat ontdekt. In de studies beschreven in dit proefschrift werden de voorspellende waardes onderzocht van taalmijlpalen en risicofactoren voor het hebben van TOS. De uitkomsten lieten zien dat vanaf de leeftijd van 2 jaar het niet halen van een taalmijlpaal aangeeft dat er een grote kans is dat het kind op de schoolleeftijd TOS zal hebben. Met behulp van de uitkomsten werd een beknopt screeningsinstrument, bestaande uit vijf taalmijlpalen op drie verschillende leeftijden, geconstrueerd. Met dit instrument zouden veel kinderen met TOS kunnen worden opgespoord voor start op de basisschool. Van alle onderzochte risicofactoren, hadden alleen de leeftijd van moeder, de plaats in de kinderrij en het krijgen van borstvoeding direct na de geboorte, een relatie met TOS. Ook werd gevonden dat kinderen met TOS niet alleen vaker later waren met het bereiken van taalmijlpalen, maar ook van motorische mijlpalen. De vraag rijst dan ook of TOS een losstaande stoornis is of vaker gepaard gaat met meer ontwikkelingsproblematiek. Adviezen werden gegeven om de vroegopsporing van kinderen met TOS in Nederland te verbeteren. Dit zou, zonder veel extra inspanning, kunnen door gebruik te maken van gegevens die al genoteerd worden binnen de huidige werkwijze van de jeugdgezondheidszorg in Nederland.Een taalontwikkelingsstoornis of TOS is waarschijnlijk de meest voorkomende ontwikkelingsstoornis en komt voor bij ca 7% van de kinderen. Een stoornis in de taalontwikkeling is een ernstige belemmering voor een optimale ontplooiing van een kind en daarmee voor zijn of haar toekomstige plek in de samenleving. Toch worden veel kinderen met TOS pas laat ontdekt. In de studies beschreven in dit proefschrift werden de voorspellende waardes onderzocht van taalmijlpalen en risicofactoren voor het hebben van TOS. De uitkomsten lieten zien dat vanaf de leeftijd van 2 jaar het niet halen van een taalmijlpaal aangeeft dat er een grote kans is dat het kind op de schoolleeftijd TOS zal hebben. Met behulp van de uitkomsten werd een beknopt screeningsinstrument, bestaande uit vijf taalmijlpalen op drie verschillende leeftijden, geconstrueerd. Met dit instrument zouden veel kinderen met TOS kunnen worden opgespoord voor start op de basisschool. Van alle onderzochte risicofactoren, hadden alleen de leeftijd van moeder, de plaats in de kinderrij en het krijgen van borstvoeding direct na de geboorte, een relatie met TOS. Ook werd gevonden dat kinderen met TOS niet alleen vaker later waren met het bereiken van taalmijlpalen, maar ook van motorische mijlpalen. De vraag rijst dan ook of TOS een losstaande stoornis is of vaker gepaard gaat met meer ontwikkelingsproblematiek. Adviezen werden gegeven om de vroegopsporing van kinderen met TOS in Nederland te verbeteren. Dit zou, zonder veel extra inspanning, kunnen door gebruik te maken van gegevens die al genoteerd worden binnen de huidige werkwijze van de jeugdgezondheidszorg in Nederland.

After several recent flight safety events, such as the accident of Air France flight 447 in 2009, investigators determined that surprise and startle can severely disrupt pilot responses. They concluded that pilots need to be better prepared for unexpected and potentially startling situations. In response, aviation safety authorities have recommended and mandated that startle and surprise should receive more attention in pilot training. However, there is insufficient scientific data available on pilots’ behavior in startling and surprising situations, and on how they can best be trained for these situations. This thesis addresses this problem, by studying startle and surprise in pilots, and by investigating which training interventions can strengthen the pilots’ response to unexpected situations...

In this dissertation it is shown that primary school children with higher levels of physical fitness and better developed motor skills perform better at school. These relations were found to depend on the academic domain, as physical fitness predicted achievement in reading and mathematics, whereas motor skills were predictive of mathematics and spelling. Executive functions provided an explanation for the relations between physical fitness and academic achievement: fitter children had a better developed working memory, of which verbal working memory predicted performance in mathematics and spelling, and visuospatial working memory predicted mathematics specifically. Functional MRI was used to examine whether brain activation patterns could explain the relations of physical fitness and motor skills with visuospatial working memory. No support was found for this presumed explanation. Following, it was examined whether two 14-week interventions during physical education, one focused on aerobic physical activity, one on cognitively-engaging physical activity, improved children’s academic achievement. In addition, changes in brain activation patterns where examined to explain these presumed effects. Children who participated at a higher intensity level performed better in mathematics after both interventions, and in spelling after the cognitively-engaging intervention specifically. Although evidence was not overwhelming, there were some indications that physical activity brought about effects on brain activation, with different changes depending on the type of physical activity used. Providing children with more physical activity during school hours can thus have positive effects on academic achievement, as long as the intensity level and amount of cognitive engagement are taken into account.

Continental collision and subduction dynamics are often the main tectonic processes responsible for the formation of mountain belts. Understanding the mechanics of deformation across collisional orogens is of prime importance in order to determine the mountains architecture and the associated deep mantle-scale geodynamic processes. The Dinarides orogen is a world-class example of a collisional orogen that was affected by a number of critical processes driving mountain building and subsequent collapse during its Jurassic-Eocene evolution associated with the convergence between Europe- and Adriatic derived units. Such processes include linked migration of slab and magmatism during continental collision, indentation of continental micro-plates, changes in polarities in respect to neighboring orogens or transfer of deformation between active areas driving the distribution of present-day seismicity and crustal stresses. All these processes are critical for the evaluation of geo-resources in the upper crustal domain and their quantification is important to be ported to the understanding of other orogens worldwide. The large-scale kinematic evolution of the Dinarides has been obtained by an extensive surface kinematic study performed in the less known area of the external Dinarides. By correlating the kinematics with available geophysical and evolutionary constraints, we constructed two large-scale, kinematically controlled regional transects. The results demonstrate a long-lived evolution of shortening that affected the Dinarides lower orogenic plate. While the Late Jurassic-earliest Cretaceous deformation was associated with an earlier obduction moment, the latest Cretaceous onset of continental collision has gradually focused deformation at inherited rheological weakness zones. We show that shortening was interrupted by a period of Miocene extension that affected all orogenic areas. The extension was followed by renewed shortening, which started during the late Miocene and remains presently active. These results indicate a lower plate crustal accretion mechanism that was spatially and temporally connected with gradual slab retreat in the Dinarides. The structural and kinematic effects of the post- middle Miocene Adriatic indentation in the NW-SE oriented Dinarides structure have been analysed in more detail. This deformation induced a characteristic coherent regional system of large offset dextral strike-slip faults, which transfer gradually their offsets to thrusts and high-angle reverse faults. By linking the data in a regional context, the post-middle Miocene Dinarides fault system seems to accommodate the differential motion between the N- ward Adriatic indentation in the Alps and the rapid S- to SW- ward movement of a Hellenides area situated SE of the Kefalonia Fault driven by the Aegean slab-roll back. The effects of the kinematic, structural and regional geodynamics on the thermal, fluid-flow and organic matter maturity evolutions were further explored by the means of a numerical modelling study performed on a kinematically controlled cross-section. The modelling results demonstrate that deformation-, burial- and exhumation-, and erosion- and sedimentation- rates significantly contribute to changes in the thermal/maturity distribution across the orogen. In addition, petrographic and geochemical (stable oxygen and carbon isotopic) investigations of samples that were taken from major fault contacts, demonstrate the significant impact of the tectonic-induced paleo-fluid flow on the diagenetic evolution of rocks across the external Dinarides.

Het doel van dit proefschrift is om factoren te identificeren die van invloed zijn op het voorkómen van ziekteverzuim en bevorderen van werkhervatting. Daarnaast is het doel om interventies, gebaseerd op deze factoren, te ontwikkelen en te evalueren.

At just 46% in 2017, the vaccination percentage for HPV (human papillomavirus) is low in the Netherlands. This dissertation describes the development and evaluation of an online intervention with tailored advice on the HPV vaccine. We developed a website that provided mothers with personal and interactive guidance to help them decide whether or not to vaccinate their daughters against HPV. The intervention helped mothers make a more informed decision and made them more willing to vaccinate their daughters. Next year, the intervention will be included in the national education programme for HPV vaccination. The online intervention may have a considerable social impact, as it can reach a large target group at relatively low costs.

First chapter provides the background on today’s worldwide developments in the field of selective atomic layer processing involving material deposition and etching. These techniques hold great potential in mitigating the process complexity and development costs currently faced by the semiconductor industry. In order to fully exploit the potential of these techniques in modern (three-dimensional) device fabrication, knowledge regarding challenges in state-of-the-art nanomanufacturing is a prerequisite. In this chapter an outline of selective atomic layer processing techniques is given to provide a bird’s eye perspective of nanomanufacturing and to guide the reader in comprehending the prospects of atomic layer processing. It is important to note that the results of this dissertation are not solely aimed at specific applications in semiconductor manufacturing but more at investigating atomic layer processing techniques. The main objective was to develop area-selective deposition as well as selective etch processes using several materials as case studies. At the same time, this has shed light on the chemical and physical phenomena imparting selectivity in atomic layer processing. The insights thus obtained are expected to contribute towards the implementation of selective atomic layer processes not only in the field of semiconductor nanoelectronics but also in other application fields such as photovoltaics, displays, catalysis, etc.

This report regards a master’s thesis in wind energy. The research for this thesis is done at ECN part of TNO. The thesis itself is part of a master Aerospace Engineering at Delft University of Technology. Prior to this thesis, a literature study has been done, resulting in a literature report on the same topic. The research topic regards the relationship between inflow conditions and wind turbine fatigue loading. Basic knowledge of wind turbines and of the atmospheric boundary layer is considered pre-knowledge for this report. Knowledge in machine learning and unsupervised machine learning in particular is not required to read this report. However, as it regards the most important parts of the research method, it can be of use. This report is divided into two parts. The first part can be used to determine a methodology for other projects with a similar research problem. In this case it can also be advised to read through the third and fourth section of Chapter 9. For readers specifically interested in wind turbine fatigue loading, the second part is most important. However, in order to properly understand the used research methods especially Section 3.2 is required reading. The second part can also be of interest for atmospheric scientists. In this case, Chapter 5 is of most relevance. I am thankful for the opportunity offered by ECN part of TNO. In particular, I would like to thank Wouter Engels for his supervision of the research project. I am also grateful to Simon Watson for being my responsible supervisor at the university.

An increasing number of young people are confronted with sexually transgressive behavior, such as sexting (sending and receiving sexual images or messages against someone's will), sexual remarks and dating violence. Two existing Dutch teaching programs on sex and relationships, and in particular on the occurrence of sexually transgressive behavior of young people, were evaluated for this PhD research: Benzies & Batchies and Jongens. Based on the positive results found, the thesis concludes that such curriculum can be used to prevent young people's unacceptable behavior; the programs must take account of differences between the sexes and the level of development of the pupils. This dissertation offers support to professionals who develop preventive interventions, and to professionals who work with young people in schools, such as teachers and school staff.

Ontwerpen van leeroplossingen voor kinderen die het moeilijkst bereikt kunnen worden. Leren rekenen met een rekengame voor kinderen in Soedan die niet naar school gaan (met een samenvatting in het Nederlands).

The worldwide production of carbon nanotubes (CNTs) has increased substantially in the last decade as the material offer society new opportunities for effectively stronger, lighter, better electrically conductive, and more flexible products. However, concerns have been raised about (occupational) health risks due to CNT exposure, but understanding of the specific hazard potential of CNTs is complicated by its variability in structure and size. In addition, an accurate risk assessment is further hindered by difficulties in measuring CNT exposure and limited exposure data for the different stages of the CNT product life cycle. This thesis contributes to the safe(r) use of CNTs and provides scientific knowledge concerning 1) a comprehensive exposure assessment method for multi-walled (MW)CNTs, 2) the identification of activities and exposure determinates which significantly contributes to MWCNTs exposure across the product life cycle and 3) the observation of an indication of endothelial activation and an increased inflammatory reaction associated with MWCNT exposure. Based on the conclusions of this research the following recommendations are made: 1) The use of less hazardous functionalized forms of CNTs, which are identified based on physical and chemical characteristics of products, should be stimulated, 2) Conservative soft laws (soft regulatory agreements) could help society adapt to the pace of innovation safely and should be considered, and 3) A mandatory European exposure registration for the increasing number of workers exposed to CNTs is suggested as health effects are still largely unknown.

Non-alcoholic fatty liver disease (NAFLD) has rapidly become the most common cause of chronic liver disease, and its worldwide prevalence continues to increase in parallel of the obesity epidemic. NAFLD comprises a wide spectrum of liver damage ranging fat accumulation (steatosis) to steatosis with inflammation (non-alcoholic steatohepatitis, NASH), which can further progress to fibrosis. In particular patients with NASH have increased risk to develop other metabolic complications, such as cardiovascular disease.NAFLD is a complex disease, in which the origin and molecular mechanisms controlling the progression of simple steatosis to NASH remain poorly understood. Nevertheless, it is thought that inflammation is a critical component of NAFLD progression. This inflammation may be triggered by metabolic surplus (excess of energy or nutrients) and is also referred to as “metabolic inflammation”. White adipose tissue (WAT) is assumed to be largely involved in the development of metabolic inflammation. The studies described in this thesis contributed to the understanding of the role of WAT in the development of NAFLD and provide insight into the molecular processes that cause metabolic inflammation.

We studied a novel triage approach to the organisation of routine assessments by Preventive Child Health care (PCH), including task-shifting among professionals. In the triage approach, access to PCH, and the detection of the health problems studied, were comparable with the usual approach. The efficient deployment of PCH professionals using triage and task-shifting reduced the costs and involvement of PCH physicians and nurses in routine assessments, particularly in the youngest age group (5 to 6 years). The associated release of workforce and budgets may create more opportunities for the delivery of care to children and their families with specific health-care needs. In our study, in the triage approach PCH physicians and nurses provided more demand-driven care at the request of parents and others such as school professionals. We have emphasised the importance of making the PCH programme more flexible to create time for PCH professionals to collaborate with professionals from the school system, and from the youth care and primary care systems, with the aim of improving joint commitment to early detection, and the delivery of more coordinated care. More research is needed into the outcomes of referral to extra care and into the cost benefits of the triage approach.

The origin of particulate matter (PM) concentrations in the Netherlands is established using the LOTOS-EUROS model with a source attribution module. Emissions from the ten main economic sectors (SNAP1) were tracked, separating Dutch and foreign sources. Of the modelled PM10 in the Netherlands, about 25% comes from natural sources and 75% is of anthropogenic origin. Dutch sources contribute one third to the anthropogenic part, with the highest contributions from transport and agriculture. During episodes, the contribution of foreign sources becomes more important. This source attribution is based on model results only, and LOTOS-EUROS captures only about 60% of the measured concentrations. This is mainly caused by a strong underestimation of the concentration of organic carbon particles. Reducing the missing mass is an important step to improve the source attribution of PM. Source attribution of PM has also been performed for Flanders, with a focus on agriculture. Flanders has a large agricultural sector and therefore considerable ammonia emissions, which contribute to secondary inorganic aerosol formation. Manure transport data was used to estimate the temporal variability of ammonia emission from manure application in the LOTOS-EUROS model. This approach strongly improves the model performance for ammonia, but does not affect secondary inorganic aerosol. A scenario study showed that restricting manure spreading shortly before and during a period with high particulate matter concentrations is not an effective way to reduce particulate matter concentrations during these episodes. Two papers in this thesis investigate possible consequences of energy transitions for air quality. During the energy transition from fossil fuels to renewable alternatives there is likely a phase in which fossil fuel energy production will be mainly used to provide back-up capacity. This causes a change in the temporal emission variability from power plants. The effect of this projected shift in emission timing on air pollutant concentrations is assessed. For all PM components considered, air concentrations in a model experiment accounting for the change in emission timing were higher than expected based on the emission change. As back-up capacity, power plants are more likely to operate during stagnant weather conditions and during nighttime in this transition phase, conditions in which air pollution is transport and dilution is ineffective. This work illustrates that emission timing is important to look into when assessing the impacts of system changes on air quality. The second scenario study focuses on ozone. When bioenergy use in increased, more production area is needed causing a change in land use. In this work the effects of land use change as well as changes in anthropogenic emissions are taken into account using realistic energy and air quality scenarios for Europe. The increase in ozone damage caused by increased production of biomass is only marginal compared to the reduction in ozone damage because of reduced ozone precursor emissions in other sectors. The total effect is a significant reduction in health damage due to ozone, especially in southern Europe. However, taking into account the effects of projected climate change, ozone damage towards 2050 might actually increase.

Innovatieteams zijn succesvoller als hun werkomgeving 'mindful' is waardoor zij in staat zijn probleemsituaties op te lossen, zo blijkt uit het promotie-onderzoek van Peter Oeij. Hierdoor daalt de faalkans van innovatieprojecten en daarmee kunnen desinvesteringen worden verkleind. De slaagkans van innovatieprojecten neemt toe. Voor dit promotieonderzoek bestudeerde Peter Oeij 18 projectteams en hun innovatieprojecten. De nadruk lag op teamdynamiek. Hoe gaan teams om met kritieke incidenten in hun project, die aanleiding kunnen vormen voor falende projecten? En dus mislukte innovaties. De promovendus stelde vast dat twee kenmerken de kans op succes vergroten. Dat is ten eerste de aanwezigheid van een 'mindful' werkomgeving. Dat wil zeggen een teamklimaat waarin sprake is van vier factoren. Allereerst psychologische veiligheid, om fouten te mogen maken. Daarnaast een teamleerklimaat, waarin kan worden geëxperimenteerd. Verder is inspraak over de gang van zaken van teamleden ('team voice') belangrijk. En vervolgens dient leiderschap in staat te zijn synergie te halen uit soms tegenstrijdige belangen, zoals: wees vernieuwend, maar let op de centen.

Goed onderwijs is de drijfveer van onze kennismaatschappij. Goed onderwijs kan excellent onderwijs worden als het niveau van doceren verbetert. Het niveau van doceren zal gemakkelijker verbeteren als een schoolorganisatie goed functioneert. Het verbeteren van het doceerniveau wordt echter bemoeilijkt door de mate van stress waar docenten mee kampen. In geïndustrialiseerde landen is de onderwijssector (één van de) koploper(s) in de mate waarin werkstress ervaren wordt. Europese schattingen van het stressniveau van docenten zijn twee keer zo hoog als de stressniveaus in andere beroepen. Werkstress leidt veelal tot verscheidene mentale en fysieke gezondheidsproblemen, maar ook tot negatieve organisatieuitkomsten (bijv. uitval uit werk) en verhoogde maatschappelijke kosten. Deze gevolgen zijn vooral alarmerend in het licht van een krimpende beroepsbevolking. Onderzoekers hebben gesteld dat sommige van deze gevolgen mogelijk voorkomen kunnen worden als adequate maatregelen worden getroffen. Echter, het wetenschappelijke bewijs voor de meest effectieve manieren om werkstress bij docenten te verminderen is niet sluitend. Om beter te begrijpen hoe we werkstress kunnen verminderen, is meer kennis over individuele en organisatorische determinanten van werkstress nodig voor specifieke beroepsgroepen waaronder medewerkers in het onderwijs. Ook zijn er nog methodologische problemen op te lossen, zoals het vaststellen van causaliteit bij de implementatie van interventies voor werknemersgezondheid. De doelstelling van dit proefschrift was het verkennen van manieren om werkstress bij docenten te verminderen en zo uiteindelijk bij te dragen aan excellent onderwijs. Drie kernvragen waren leidend in deze verkenning: (1) Hoe kunnen we werkstress bij docenten verminderen vanuit individueel perspectief? (2) Hoe kunnen we werkstress bij docenten verminderen vanuit organisatieperspectief? (3) Hoe kunnen we het meest relevante bewijs verzamelen in interventieonderzoek in de werkcontext?

In Nederland krijgen jaarlijks 40.000 mensen in de werkende leeftijd een diagnose kanker. Uit onderzoek blijkt tevens dat het aantal mensen dat vanwege kanker een ziektewet- of WIA-uitkering aanvraagt, al jaren stijgt. Als je kanker krijgt heb je een kwetsbare positie op de arbeidsmarkt. Zelfs 1 op de 4 Nederlandse kankerpatiënten verliest zijn baan tijdens of na de behandelingen. Ze onderzocht in de afgelopen vier jaar hoe mensen met kanker in de ziektewet en WIA weer begeleid kunnen worden bij het vinden van een baan. Uit haar onderzoek blijkt duidelijk dat deze doelgroep behoefte heeft aan ondersteuning waarbij maatwerk nodig is. Daarbij is het belangrijk dat artsen en het UWV het onderwerp werkhervatting niet pas ver in het herstelproces aan kaarten.

Personaliseren van roosters, bijvoorbeeld naar chronotype, van belang bij ploegendiensten bij oudere werknemers. In dit proefschrift is de aanname onderzocht dat werken in ploegendienst zwaarder wordt met toenemende leeftijd en in hoeverre roosters kunnen helpen bij het duurzaam inzetbaar houden van oudere ploegendienstwerknemers. In drie studies is geen consistent bewijs gevonden dat oudere ploegendienstwerknemers meer problemen ervaren met werken in ploegendienst dan jongere werknemers. Andere factoren, zoals het chronotype (de mate van ochtend- of avondmens), bleken beter individuele verschillen in slaap en herstelbehoefte te verklaren dan leeftijd. In drie andere studies is gevonden dat roosters die voldoen aan ergonomische roostercriteria kunnen bijdragen aan de duurzame inzetbaarheid van ploegendienstwerknemers. Het proces voorafgaand aan de implementatie van een nieuw rooster bleek echter minstens even belangrijk als het roosterontwerp zelf over hoe werknemers een nieuw rooster ervaren. Mogelijke verklaringen voor deze resultaten zijn dat alleen de sterksten blijven werken in ploegendiensten en dat collectieve roosters weinig ruimte bieden aan individuele wensen. Met de verhoging van de pensioensleeftijd en het groeiende aantal oudere ploegendienstwerknemers, komen ontziemaatregelen voor oudere ploegendienstwerknemers onder druk te staan. Er is daarom meer onderzoek nodig hoe alle ploegendienstwerknemers inzetbaar te houden tot aan het pensioen. Een interessante strategie om verder te ontwikkelen is het personaliseren van roosters, bijvoorbeeld naar chronotype.

In the modern world, networked sensor technology makes it possible to capture the world around us in real-time. In the security domain cameras are an important source of information. Cameras in public places, bodycams, drones and recordings with smart phones are used for real time monitoring of the environment to prevent crime (monitoring case); and/or for investigation and retrieval of crimes, for example in evidence forensics (forensic case). In both cases it is required to quickly obtain the right information, without having to manually search through the data. Currently, many algorithms are available to index a video with some pre-trained concepts, such as people, objects and actions. These algorithms require a representative and large enough set of examples (training data) to recognize the concept. This training data is, however, not always present. In this thesis, we aim to assist an analyst in their work on video stream data by providing a search capability that handles ad-hoc textual queries, i.e. queries that include concepts or events that are not pre-trained. We use the security domain as inspiration for our work, but the analyst can be working in any application domain that uses video stream data, or even indexed data. Additionally, we do only consider the technical aspects of the search capability and not the legal, ethical or privacy issues related to video stream data. We focus on the retrieval of high-level events, such as birthday parties. We assume that these events can be composed of smaller pre-trained concepts, such as a group of people, a cake and decorations and relations between those concepts, to capture the essence of that unseen event (decompositionality assumption). Additionally, we hold the open world assumption, which means that the system does not have complete world knowledge. Although current state of the art systems are able to detect an increasingly large number of concepts, this number still falls far behind the near infinite number of possible (textual) queries that a system needs to be able to handle. In our aim to assist the analyst, we focus on the improvement of the visual search effectiveness (e.g. performance) by a semantic query-to-conceptmapping: the mapping from the user query to the set of pre-trained concepts. We use the TRECVID Multimedia Event Detection benchmark, as it contains high-level events inspired by the security domain. In this thesis, we show that the main improvements can be achieved by using a combination of i) query-to-concept mapping based on semantic word embeddings (+12%), ii) exploiting user feedback (+26%) and iii) fusion of different modalities (data sources) (+17%). First,we propose an incrementalword2vec (i-w2v) method, which usesword2vec trained on GoogleNews items as a semantic embedding model and incrementally adds concepts to the set of selected concepts for a query in order to deal with query drift. This method improves performance in terms of MAP compared to the state of the art word2vec method and knowledge based techniques. In combination with a state of the art video event retrieval pipeline, we achieve top performance on the TRECVID MED benchmark regarding the zero-example task (MED14Test results). This improvement is, however, dependent on the availability of the concepts in the Concept Bank: without concepts related to or occurring in the event, we cannot detect the event. We, thus, need a properly composed Concept Bank to properly index videos. Second, we propose an Adaptive Relevance Feedback interpretation method named ARF that not only achieves high retrieval performance, but is also theoretically founded through the Rocchio algorithm from the text retrieval field. This algorithm is adjusted to the event retrieval domain in a way that the weights for the concepts are changed based on the positive and negative annotations on videos. The ARF method has higher visual search effectiveness compared to k-NN based methods on video level annotations and methods based on concept level annotations. Third, we propose blind late fusion methods that are based on state of the art methods, such as average fusion or fusion based on probabilities. Especially the combination of a Joint Ratio (ratio of probabilities) and Extreme Ratio (ratio of minimum and maximum) method (JRER) achieves high performance in cases with reliable detectors, i.e. enough training examples. This method is not only applicable to the video retrieval field, but also in sensor fusion in general. Although future work can be done in the direction of implicit query-to-concept mapping through deep learning methods, smartly combining the concepts and the usage of spatial and temporal information, we have shown that our proposed methods can improve the visual search effectiveness by a semantic query-to-concept mapping which brings us a step closer to a search capability that handles ad-hoc textual queries for analysts.

Concrete is commonly used in protective and civil structures, like tunnels and storage buildings. For the design and reliable safety assessment of such structures it is very important to know the behaviour of concrete under static loading conditions as well as under impulsive loading. To understand the behaviour of concrete under impulsive loading and to be able to predict the failure behaviour, it is important to know the influence of the loading rate on concrete strength and failure parameters and to quantify how they change with increasing loading rate. The fact that material parameters depend on the applied loading rate is called rate dependency. Objectives The mechanical response of concrete structures is often predicted with numerical material models in a finite element context. To properly predict the response of structures under impulsive loading, the rate dependency should be included explicitly in the material model. To validate a physically realistic concrete material model for high loading rates, experimental data on the rate dependency of concrete tensile strength and fracture properties is needed. Data which shows the influence of the loading rate on the mechanical parameters like strength and stiffness can be found in literature for low as well as high loading rates (> 1000 GPa/s). However, data on the rate dependency of the fracture energy, and especially the fracture behaviour, is scarce. Therefore, the objective of this study is to quantify the rate effect on the tensile strength and stiffness at medium and high loading rates, as well as to determine the stress-displacement relation that reflects the fracture process and determines the fracture energy. Besides experimental data on the rate dependency of concrete properties, it is also important to understand the physical mechanisms behind the rate effects. The physical mechanisms will explain the change in concrete behaviour under dynamic loading conditions. A detailed analysis of the causes behind the rate dependency of concrete is missing in literature. There is no common explanation of the underlying mechanisms of the rate dependency of concrete tensile properties. Therefore, one of the objectives of this study is to identify the different mechanisms behind the rate effects on tensile properties and to quantify the influence of the different mechanisms. To gain detailed information on the mechanisms behind the rate dependency and to be able to quantify the influence of the different mechanisms, information on the rate effects on fracture characteristics (width of the fracture zone, crack distribution and crack /fracture lengths) is needed. The experimental research (at macro level) is, therefore, combined with microscopic research. Experimental program A research program has been developed to study the rate dependency of concrete tensile fracture properties. To study the rate effect on the tensile properties of concrete, uniaxial tensile test are conducted at three different loading rates: - Static loading rate as a reference; loading rate 10-4 GPa/s; - Moderate loading rate with the gravity driven Split Hopkinson Bar set-up (SHB) at the Delft University of Technology; loading rate 50 GPa/s; - High loading rate with a newly developed Modified Split Hopkinson Bar set-up (MSHB) at the laboratory of TNO in Rijswijk; loading rate > 1000 GPa/s. From literature it was concluded that the moisture in the pores plays an important role in the rate dependency of concrete properties, especially in the moderate loading rate regime (up to 50 GPa/s). Therefore, it was decided to study the influence of moisture on the rate dependency of the tensile fracture properties by varying the loading rate, moisture content and micro structure. To study the influence of the micro structure, two types of concretes are used; Portland cement concrete and Blast Furnace Slag (BFS) cement concrete. BFS cement concrete has a denser micro structure with less capillary pores. To study the influence of moisture in the pore system on the rate effects on concrete tensile properties, the concrete specimens have been subjected to four different moisture conditions for approximately 21 days (after being drilled out of the cubes at an age of 28 days). The four different moisture conditions are: - “Normal” condition: specimens are stored under controlled conditions of 20°C and 50% RH; - “Wet” condition: specimens are immersed in water; - “Dry-50” condition: specimens are dried in an oven of 50°C and 15% RH; - “Dry-105” condition: specimens are dried in an oven of 105°C and 2% RH. After the uniaxial tensile tests are finished, the fracture patterns have been studied by impregnating the cracks with epoxy and studying them by microscope. The influence of the rate dependency on the fracture parameters has been determined by quantifying the rate effects on the lengths of the different cracks and on the width of the fracture zone. Test set-ups For the static tests (loading rate 10-4 GPa/s), deformation controlled uniaxial tensile tests have been performed on cylindrical concrete specimens (Ø 74 mm, length 100 mm). The gravity driven Split Hopkinson Bar is used to conduct the uniaxial tensile tests at moderate loading rate (50 GPa/s). This SHB set-up consists of two cylindrical aluminium bars between which the concrete specimen (Ø 74 mm, length 100 mm) is glued. The tensile stress wave is generated with a drop weight, which slides along the lower bar and hits an anvil at the bottom end. The tensile wave travels upwards through the aluminium bar and through the specimen, fracturing the specimen when the tensile strength of the concrete is reached. For the very high loading rates (> 1000 GPa/s) a new Modified Split Hopkinson Bar (MSHB) set-up is used. The Modified Split Hopkinson Bar is based on a different principle than the Split Hopkinson Bar, i.e. the principle of spalling. A shock wave is introduced into a horizontal steel bar by detonating an explosive charge at one end of the bar. At the other end, the concrete specimen is attached which is first loaded in compression and will fail in tension due to the reflected tensile wave (spalling). In the Modified Split Hopkinson Bar set-up a new innovative measurement technique was used, enabling direct measurement of strains and deformations of the loaded specimens. The direct measurement method used in the Split Hopkinson Bar and Modified Split Hopkinson Bar set-ups generates information on real-time strains and deformations. This makes it possible to reconstruct failure behaviour and has given insight in the different causes of the observed rate effects. Experimental results For the moderate loading rates (50 GPa/s) an increase of the tensile strength of approximately 2 MPa is found for dry and normally cured concrete compared to the static tests. For wet concrete, the increase in tensile strength was found to be more pronounced, approximately 4 MPa for Portland cement concrete and 3 MPa for Blast Furnace Slag cement concrete. At high loading rates (1700 – 2450 GPa/s), the tensile strength results have shown an increase of approximately 5-7 MPa for normal and dry concrete and 12-15 MPa for wet concrete. The fracture characteristics, i.e. fracture lengths and widths of the fracture zone, and the failure behaviour have been quantified by measuring the individual and summarized crack lengths and determining the stress-deformation curves. From the results it was concluded that the width and length of the macro fracture are not influenced by the loading rate. For normally cured and dry concrete and loading rates up to 50 GPa/s, the fracture energy, shape of the stress-deformation curve, width of the fracture zone and the number of micro cracks are hardly affected by the loading rate. Wet concrete shows enhanced resistance in the post-peak phase of the stress-deformation curve. For the high loading rate regime (> 50 GPa/s) the total summarized length of the micro cracks and the width of the fracture zone increase considerably, as well as the resistance in the post-peak phase of the stressdeformation curve and the fracture energy. Mechanisms With the available experimental data on tensile strength, fracture characteristics and postpeak failure behaviour, the failure mechanisms have been reconstructed and the main causes for rate dependency of the tensile strength and fracture resistance have been identified. The most important possible causes are (1) structural inertia of the fracture zone, (2) influence of inertia at micro-level which can delay crack initiation and propagation, (3) additional micro cracking and (4) enhanced fracture resistance caused by moisture in the pores (Stefan effect). By using basic principles of fracture mechanics and a simple model based on the Stefan effect, the different mechanisms and the loading rates at which these mechanisms have significant effect have been determined. Nuclear Magnetic Resonance and Mercury Intrusion Porosimetry results provide necessary data on moisture distribution in the pore system. Structural inertia effects For the experimental data from the presented research and the method used to measure and analyse the data (1D approach), it was shown that structural inertia of the fracture zone (axial direction) does not contribute to the obtained enhanced tensile strength for the moderate as well as the high loading rate regime. Also, structural inertia of the fracture zone hardly affects the post peak behaviour of concrete. This holds for all concrete types and moisture contents studied. Effect of micro inertia, Stefan effect and additional cracking The mechanism which causes the strength increase due to moisture in the pores is the so called Stefan effect. The Stefan effect is explained as the reaction force, which is induced when two plates with moisture in between are separated. The equation to calculate the Stefan effect is modified to fit concrete pore structure properties. To incorporate the concrete structure, it is assumed that the Stefan effect is valid for cylindrical pores. From the NMR data combined with the experimental data on strength and fracture energy and the Stefan effect model, it was concluded that only the moisture in the capillary pores contributes to the enhanced tensile strength and post-peak resistance. The dominant mechanism in the moderate loading rate regime (< 50 GPa/s) causing the tensile strength increase due to moisture in the pores is the Stefan effect. In the high loading rate regime, both the Stefan effect and the micro inertia effects on crack propagation due to the limitation on crack velocity contribute to the increase in tensile strength. The enhanced fracture resistance in the post peak behavior for wet concrete and moderate loading rates up to 50 GPa/s has been ascribed to the viscous effects of moisture in the concrete pores (Stefan effect). For the high loading rate regime, loading rates exceeding 50 GPa/s, the enhanced resistance in the post-peak behaviour is partly caused by the formation of additional (micro) cracks. However, the increase in (micro) crack length is insufficient to explain the observed high fracture energy increase for the high loading rate regime. Therefore, the increased fracture toughness in the post-peak behaviour in the high loading rate regime has been explained by the formation of additional (micro) cracks as well as the viscous behaviour of concrete (wet concrete) and by the micro inertia effects due to material inherent limitation of the crack velocity. Future application The acquired knowledge on the mechanisms behind the rate dependency of concrete fracture properties can be used to improve numerical models. One of the most commonly used approaches to model concrete fracture is the application of continuum models. The properties and behaviour of the elements in a continuum model are defined by a constitutive law, which also determines the change in properties when fracture takes place. For modelling failure under dynamic loading conditions, the mechanisms behind the rate effects on concrete tensile properties, i.e. moisture in the capillary pores, additional micro cracking and micro inertia effects due to limitations on crack velocity, should be incorporated into the constitutive material model. Which mechanisms should be incorporated into the material model depends on the scale at which modelling takes place. The presented research has also shown that for modelling dynamic experiments the internal material length scale, an important parameter to model fracture processes, should be based on the width of the macro fracture zone and connected micro cracks. This zone contains the macro crack, which physically separates the specimen in two halves, as well as the micro cracks that are attached/connected to the macro crack. The width of the macro fracture zone with connected micro cracks does not significantly change with increasing loading rate. Subsequently, the internal length scale as defined for a specific model also does not significantly change with increasing loading rate. The dominant mechanisms found in the presented research can be implemented in dynamic models and the acquired data set1 can be used to validate the developed models. With the suggested dominant mechanisms and knowledge on the rate dependency of the concrete tensile strength and fracture behaviour, the response of concrete materials under dynamic loading can now be better understood and predicted more accurately.

This thesis aimed to increase the knowledge about severe forms of anxiety, gagging and fainting in dentistry and to investigate whether these phenomena are overlapping or separate constructs. In Chapter 2 a literature review of twin studies showed that the estimated heritability of specific phobias and fears varied widely. In Chapter 3 a framework was developed to classify dental fear, resulting in a three factor solution consisting of fear of invasive treatment, lack of self-control and physical sensations. In Chapter 4 the characteristics of memories underlying various levels of dental anxiety were described. Two-third of the memories of the dental phobics showed characteristics of PTSD, and only 8% of the memories of the low anxious individuals. In Chapter 5 was examined how the ‘vividness’ and ‘disturbance’ of a memory of a dental treatment changed over time in low and highly anxious individuals. In both groups a significant decline in memory vividness was observed, but where the disturbance of the memory of the highly anxious individuals increased significantly, it remained stable in the low anxious group. In Chapter 6 the co-occurrence of dental phobia and fainting was examined. Only 13.0% of the dental phobics reported to faint, supporting the notion that anxiety and fainting in dentistry are separate constructs. In Chapter 7 gagging in dentistry was investigated. The estimated prevalence was 8.2%. That gagging and severe dental anxiety are separate constructs is supported by the finding that most of the gagging individuals (84%) did not show high anxiety levels. Chapter 3 embargo until 11 August 2017 and 5 embargo until 11 November 2017.

In an explosion taking place close to or inside a concrete structure, apart from the dangers of the explosive itself, the hazard due to the large debris originating from the concrete structure is an important threat. Protective structures with high probability to experience such extreme loadings during their service lives, such as protection walls outside important buildings or munition magazines for storing explosives, have to be designed to mitigate the effects of a probable explosion. With this goal, a PhD project was undertaken on designing and analyzing a cementitious material with sufficient static strength to carry the service loads and fractures into small-size fragments when subjected to an explosion. This thesis presents the design procedure of such a material, the experimental and numerical investigations and the results of the project. In the last decades, extensive research has been focused on understanding the behavior of concrete structures under extreme dynamic loadings. While most studies aim at designing materials that resist impact loading, the objective of this project was developing a cementitious material that is expected to fracture and disintegrate under impact. During the research, a sensitivity study was conducted on various forms of cementitious materials (Chapter 2). Porous concretes with enhanced strength, fracturing into small fragments when exposed to impact loading, were obtained and analyzed. In the process of modifying the porous concrete properties the main goal was to enhance the static strength while maintaining a high porosity. By modifying the mixture composition as well as the method of compaction, porous concretes with improved static strengths (at the range of 30-50 MPa) were produced as presented in detail in Chapter 3. In order to better understand the properties of the porous concretes produced, mechanical tests at macro and meso-scales were performed. Computer tomography, electron microscopy and X-ray diffraction analyses were also conducted to better explain the effective parameters which were summarized in Chapter 3. Among all the parameters that have been investigated, aggregate properties have the most significant effect on the mechanical properties of porous concrete. On the other hand, intense compaction in thin layers (to ensure good control of the production process), which directly affects the packing of the particles and the porosity, is essential to attain porous concretes with substantial strengths. The contribution of microsilica to the mechanical properties of porous concrete was not significant, even though the tests on the interfacial transition zone (ITZ) clearly showed that microsilica improved the strength of the ITZ phase. The reason for this „contradiction‟ was better explained by the CT scans of partially fractured samples. These scans revealed that in porous concretes crack patterns are very much influenced by the distinct porous structure and the aggregate skeleton. The cracks are forced to propagate into locations guided by the geometry of the present phases and the path does not always go through the weakest phase i.e. the ITZ. In the process of designing a material with desired dynamic performance, efficient dynamic testing techniques were highly required. In Chapter 4, dealing with the dynamic testing and evaluation of the experimental research, various experimental configurations were adapted or introduced for determining the dynamic response of porous concretes in a drop weight impact test. Different types of porous concretes and a mixture of normal concrete were subjected to drop weight impact tests. When the experimental configurations that have been used are compared, it can be concluded that stress gauge measurements have the advantage of direct measurement of the transmitted stress, while no analyses are needed afterwards to obtain the impact strength data. Among the other two monitoring and measuring techniques (LDV and high speed photography) that have been applied, LDV proved to be more accurate due to its higher sampling rate compared to high speed photography. It also has the advantage of being independent of factors such as the intensity of the light source. High speed photography, however, has its own advantage of also facilitating the visualization of the fracture process, which provides important qualitative information on the crack patterns. On the other hand, both techniques have the advantage of being non-contact methods. In the analyses of the drop weight impact test results, obtained using LDV and high-speed photography, the reverberation application of the impedance mismatch method was used. The analysis method proved to be very suitable to investigate the drop weight impact behavior of porous concretes. It also had the advantage of involving only the well-known dynamic impedance properties and the velocity measurements of the impactor, while the properties of the tested target specimen are not directly involved in the measurements and the analysis. The focus of the numerical part of the research was simulating and assessing the dynamic behavior of different porous concretes under impact loading. To achieve this goal, analyses were conducted both on real porous concretes and on fictitious (model) porous materials. The latter models were used to demonstrate better the individual factors affecting the porous concrete properties. In the research, explicit time integration was selected as the analysis method. For the realistic representation of the real concretes that were produced and tested, the aggregates present in the mixtures were directly determined through 3D computed tomography. A mesh generation program was developed for generating realistic finite element meshes. In the analyses, porous concrete was considered as a four-phase material consisting of aggregates, bulk cement paste, interfacial transition zones (ITZ) and meso-size air pores. When analyzing real porous concretes, the influences of the different parameters such as pore and aggregate size distributions and total porosity, are usually coupled. For distinguishing the sole effect of each parameter, virtual or model porous concretes were analyzed. The primary objectives of these analyses were computing the impact strength and examining the fragmentation behavior. The pore structures parameters are the most dominant factors affecting the mechanical properties of porous concretes. Therefore, model porous concretes having regularly and irregularly distributed circular pores of different radii and total porosity were analyzed. From the comparison of the impact responses of model porous concretes with different size pores, it could be concluded that for all porosities analyzed the impact strength of the concretes increased with decreasing pore size (at constant total porosity). It could also be concluded that for constant total porosity the sizes of the fragments that were formed drastically decreased when the pore size decreased. The results obtained from the analyses on the concretes with randomly distributed pores showed that for mixtures with larger pore sizes the scatter in impact strengths was larger. To understand the effect of aggregate size on the porous concrete properties, circular aggregate model porous concretes were analyzed. The results showed that the impact strengths of porous concretes with 8 mm and 4 mm particles (same porosity) were approximately the same, while the impact strength of the model porous concrete with 2 mm particles was lower. Reasons for this were explained in detail in Chapter 5: in different mixtures several factors influenced the results in opposite ways. In the numerical analyses of real porous concretes, the simulations were quite realistic. This result was achieved by applying proper finite element meshes resembling the actual porous concretes and accurate input data for the cementitious phases of the materials being quantified in the experiments at the meso-scale. Comparison of the peak values of the impact stress time histories showed that impact strengths of the samples obtained numerically (presented in Chapter 5) were in a good agreement with the experimental results. Pore and fragment size distributions of real porous concretes were also computed using the numerical models. This provided valuable information for better understanding of the fragmentation of the different mixtures. This thesis comprises experimental and numerical investigations performed on porous concretes meant to be used in safety applications. The results obtained from the enhanced strength porous concretes that have been produced were promising. The impact test monitoring methods proposed as well as the numerical analyses can be used in experimental and numerical investigation of the dynamic behavior of porous concretes.

Bij de preventie of behandeling van metabole ziekten zoals type 2 diabetes, leververvetting en aderverkalking denken we al gauw aan medicijnen. Maar ook het aanpassen van ons voedingspatroon kan helpen om de ontwikkeling van metabole ziekten tegen te gaan, of om de onderliggende processen in ieder geval af te remmen. Dat concludeert Martine Morrison in haar onderzoek naar de rol van metabole ontsteking in de ontwikkeling van metabole ziekten. Met de wereldwijde toename van ernstig overgewicht en obesitas neemt ook het aantal mensen met obesitas-gerelateerde metabole ziekten toe. Wetenschappers vermoeden dat metabole ontsteking – de ontstekingsreactie die plaatsvindt op overbelasting van de stofwisseling door het nuttigen van excessief veel koolhydraten, vetten en/of eiwitten – een belangrijke rol speelt in het ontstaan van deze ziekten. Maar hoe metabole ontsteking precies ontstaat, en hoe dit proces gestopt kan worden, is nog onbekend. Morrison onderzocht dat in proefdieronderzoek. Ze was vooral benieuwd of en hoe voedingsinterventies kunnen helpen om metabole ontsteking tegen te gaan. Morrison laat zien dat interventies die de ontstekingsreactie op metabole overbelasting kunnen onderdrukken een krachtige methode bieden om ziekteontwikkeling te remmen. Zo concludeert zij onder andere dat onverzadigde pompoenzaadolie en een extract van de blauwe bosbes (Vaccinium myrtillus L.) leververvetting en leverontsteking verminderen. In beide producten zitten fytochemicaliën met anti-ontstekingseigenschappen. De gunstige effecten komen waarschijnlijk door een afname van de ophoping en kristallisatie van vrije cholesterol in de lever. Het onderzoek laat zien dat aanpassingen in het voedingspatroon mogelijk een belangrijke rol kunnen spelen in de behandeling van metabole ziekten, naast of in plaats van medicijnen.

Absorption of toxic substances via the skin is an important phenomenon in the assessment of the risk of exposure to these substances. People are exposed to a variety of substances and products via the skin, either directly or indirectly, while at work, at home or in public space. Pesticides, organic solvents and metalworking fluids are seen to be important contributors to adverse health effects due to occupational exposure via the skin. In daily life, cosmetics, clothing and household products are the most relevant commodities with respect to exposure via the skin. Given the importance of skin exposure in the assessment of the risk of toxic substances, the objective of this thesis was to further develop, evaluate and improve methods for including skin absorption data this assessment. In this thesis, four factors influencing dermal absorption, namely dermal loading (chapters 3 and 6), irritative/corrosive potential (chapters 3 and 4), frequency of exposure (chapters 3, 4 and 5) and the vehicle used (chapter 5), were investigated in more detail. Furthermore, a model to extrapolate infinite dose absorption data to finite dose conditions, baptized Dermal Absorption Model for Extrapolation (DAME), was developed and tested. I n chapter 2 of this thesis, the relationship between relative dermal absorption and dermal loading was investigated. Hundred-and-thirty-eight dermal publicly available absorption experiments with 98 substances were evaluated. The results obtained revealed that dermal loading ranged mostly between 0.001 and 10 mg/cm2. In 87 experiments (63%), an inverse relationship was observed between relative dermal absorption and dermal loading. On average, relative absorption at high dermal loading was 33 times lower than at low dermal loading. Known skin irritating and volatile substances less frequently showed an inverse relationship between dermal loading and relative absorption. It was concluded that when using relative dermal absorption in regulatory risk assessment, its value should be determined at or extrapolated to dermal loadings relevant for the exposure conditions being evaluated. I n chapter 3 of this thesis, a literature search was presented with the aim to investigate whether neglecting the effects of repeated exposure may lead to an incorrect estimate of dermal absorption. The results demonstrated that the effect of repeated versus single exposure does not demonstrate a unique trend. Nevertheless, an increase in daily absorption was frequently observed upon repeated daily exposure. The little information available mostly concerned pharmaceuticals. However, consumers and workers may be repeatedly exposed to other types of chemicals, like disinfectants and cleaning products, which often contain biocidal active substances that may decrease the barrier function of the skin, especially after repeated exposure. These biocidal products, therefore, may present a safety risk that is not covered by the current risk assessment practice since absorption data are usually obtained by single exposure experiments. Consequently, it was decided to investigate the importance of this issue for biocide safety evaluation. As the literature search revealed that hardly any data on absorption upon repeated dermal exposure to biocides are available, it was concluded that data need to be generated by testing. To cover the entire range of biocidal products in such testing, a representative series of biocidal substances should be tested, making in vitro testing of dermal absorption the preferred choice over in vivo testing. Based on an inventory made, it appeared that the 16 product types represented among the biocidal products authorised in the Netherlands could be clustered into 6 more or less homogeneous categories based on similarity in active substances. This result could facilitate experimental testing by providing a basis for selection of a limited number of representative compounds to be evaluated. I n chapter 4 of this thesis, the importance of the effect of repeated dermal exposure on skin permeability for biocide safety evaluation was investigated, using a selection of nine representative biocides from the inventory made in chapter 3. The in vitro dermal penetration of tritiated water and [14C]propoxur was chosen as a measure of the permeability and integrity of human abdominal skin after single and repeated exposure. The results indicated that single and repeated exposure to specific biocidal products (e.g. the quaternary ammonium chlorides DDAC and ADBAC) may significantly increase skin permeability, especially when the compounds are applied at high concentrations, while a substance like formaldehyde may reduce skin permeability under specific conditions. I n chapter 5 of this thesis, the in vitro dermal absorption kinetics of the quaternary ammonium compound didecyldimethylammonium chloride (DDAC) during single and repeated exposure was studied in more detail. In addition, the influence of biocidal formulations on the absorption of DDAC was investigated, because it was expected that formulation characteristics may be another factor influencing its dermal absorption. The analysis of biocidal products on the Dutch market, reported in chapter 3, indicated that DDAC is often used in combination with other active ingredients. DDAC was most frequently combined with formaldehyde, glutaraldehyde and/or alkyldimethylbenzyl­ammo­nium chloride (ADBAC). Consequently, commercial formulations containing one or more of these additional active ingredients were selected, in addition to one formulation containing only DDAC as an active ingredient. The selected commercial formulations tended to reduce skin penetration of DDAC. This was most pronounced with the formulation containing the highest concentration of formaldehyde (196 mg/mL) and glutaraldehyde (106 mg/mL), which reduced the flux of DDAC across the skin by 95%. The reduction caused by the only tested formulation containing no other active ingredients than DDAC, and thus incorporating no aldehydes, was smallest, and did not reach statistical significance. I n chapter 6 of this thesis, a simple in silico model to predict finite dose dermal absorption from infinite dose data (kp and lag time) and the stratum corneum/water partition coefficient (KSC,W) was developed. This model was tentatively called Dermal Absorption Model for Extrapolation (DAME). As dermal exposure may occur under a large variety of conditions leading to quite different rates of absorption, such a predictive model using simple experimental or physicochemical inputs provides a cost-effective means to estimate dermal absorption under different conditions. To evaluate the DAME, a series of in vitro dermal absorption experiments was performed under both infinite and finite dose conditions using a variety of different substances. The kp’s and lag times determined in the infinite dose experiments were entered into DAME to predict relative dermal absorption value under finite dose conditions. For six substances, the predicted relative dermal absorption under finite dose conditions was not statistically different from the measured value. For all other substances, measured absorption was overpredicted by DAME, but most of the overpredicted values were still lower than 100%, the European default absorption value for the tested compounds. In conclusion, our finite dose prediction model (DAME) provides a useful and cost-effective estimate of in vitro dermal absorption, to be used in risk assessment for non-volatile substances dissolved in water at non-irritating concentrations. I n chapter 7 of this thesis, the results of the research reported in chapters 2 to 6 were put into perspective, the pitfalls and promises emanating from them discussed and general conclusions drawn. The possible influence of vehicles on absorption and the possible impact of irritative or corrosive vehicles or chemicals on the skin barrier have been demonstrated in this thesis. An in silico predictive model tentatively called DAME was developed, which enables the user to evaluate a variety of dermal exposure scenarios with limited experimental data (kp and lag time) and easy to obtain physicochemical properties (MW and log KOW). The predictions of our experiments reported in chapter 6 were compared to those of the Finite Dose Skin Permeation (FDSP) model published on the internet by the US Centers for Disease Control and Prevention (CDC). DAME outperformed FDSP (R2 of the correlation predicted/measured potential absorption 0.64 and 0.12, respectively). At present, the applicability domain of DAME is limited to non-volatile substances dissolved in aqueous solvents. However, in future the model will be adapted to include volatile substances as well. Altogether, it is concluded that dermal exposure can be an important factor in risks posed by chemicals and should be taken into account in risk assessment. The methods to actually do this are still open for further improvement to better account for the various factors influencing skin penetration and to develop adequate combinations of in vitro and in silico models that can accurately predict human dermal absorption.

Sustainable employability has recently become a topical issue in HR literature. Two major developments are responsible for this increased attention. The first is contextual change, requiring businesses to adapt to faster changing markets, causing rapid shifts in the demand for labour and skills. These shifts have severe consequences for the employability of individual employees, even causing skills to become obsolete. Also, organizational change is positively related to perceived skills mismatch. As a consequence, the vulnerable employability of less educated or uneducated employees will become ever more vulnerable as a result of contextual changes and shifting skills demands. This thesis analyses three potential routes in sustaining the employability of less educated workers: development, mobility and work redesign. It focusses on the less educated, since literature shows that less educated (older) employees are a high-risk group with regard to their sustainable employability. Less education and training, worse general health (habits) and taxing working conditions make it relatively difficult for less educated older employees to extend their working lives. Adding to this, less educated employees face several other disadvantages hindering their sustainable employability.

Many developed countries are confronted with ageing populations, due to the increase in life expectancy and long-term decline in fertility rates. As a consequence, the ratio of the retired elderly to the active working population increases. This puts a pressure on the social security system, and causes tension in the solidarity between generations. Many governments respond to the ageing of the population by increasing the statutory retirement age and discouraging early exit from the workforce. However, many workers leave the workforce before the statutory retirement age. In this thesis,investigated determinants of, and mechanisms underlying early retirement and working beyond retirement. She found that the transition from work to early retirement is influenced by various domains, i.e., health, job characteristics, skills and knowledge, and social and financial factors. These domains influenced early retirement through lower work ability, lower work motivation and less opportunity to work.

Stress is a prevalent condition in the Western world. In the Netherlands, a recent study reported the costs of stress to be around 4 billion euro per year, only factoring in work-related stress. In addition, the societal and individual impact of stress is high: the same study estimated that every year 150.000 to 300.000 people are unable to work, and one out of seven people who receive WAO (dispensation for people who are incapacitated for work) is estimated to be in that position due to stress. It is therefore relevant and beneficial to our society to perform research into stress. Research enables us to determine the factors causing stress and the systems underlying our responses to these factors, providing insights for developing prevention and therapies for stress. Therefore, we performed a series of research into the human physiological stress system. Starting point of our research was the recognition of three general requirements that must be fulfilled in stress research, in order to adequately interpret and compare the obtained results. These are: standardization of the methods used, precision of the stressor definition and control of the stress status of the human subject. To aid in fulfilling these requirements, we developed a novel application: the Generic Automated Stress Induction and Control Application (GASICA). In this application we utilized a digital game as a stressor. Moreover, a set of measurements devices and a feedback loop were used to control the stressor characteristics, and in turn the stress status of the subject. Validation of GASICA showed that the application was able to induce both acute and more chronic stress responses and was able to significantly predict the physiological response for the majority of the presented stressors. With respect to control, GASICA was found to correctly predict around 20% of the responses using individually fitted models. We concluded, however, that this is insufficient for an adequate control of the stress status. The application of GASICA as a research tool revealed fundamental insights into the working of physiological stress response system. We found that, in general, the cardiovascular system responds more specific to presented stressors than the sympathetic nervous system. We also found that the acute electrodermal response is significantly higher for non-symbolic stressors compared to symbolic stressors, and that the acute heart rate response for females is higher to visual stressors compared to auditory stressors. Finally, we found indications that the height of the acute response to a stressor combination is a linear function of the amount of stressors presented simultaneously. These insights could provide starting points for further research and potential interventions. To improve our application, we propose several development steps, such as improving the user friendliness of the application, in order to allow GASICA to be adopted as a novel standard for stress induction and control. Future use of GASICA in several fields is envisioned, for example by examining whether the individually fitted models can be used for diagnosing and/or predicting stress related illnesses. Given our findings, we believe that GASICA has potential as a standard for ecological valid research of the human physiological stress system in various research, training and therapeutic situations.

This thesis provides new knowledge on how to design comfortable passenger seats and provides recommendations for design and research. Although the first studies on passenger seat comfort appeared already 40 years ago, the activities and context have changed since then. In this thesis, relationships have been mapped out between activities (context level), anthropometric variables (human level), and seat characteristics (seat level) on the one hand, and comfort and discomfort perception of passengers on the other hand. Results obtained from experiments, performed on aircraft seats, train seats and car seats, provide a better and more practical foundation for these relationships.

Road traffic is a prominent source of environmental noise exposure in urbanized areas. Because of its common presence, traffic is a source of exposure that is not easy to avoid. As a consequence, it is affecting a substantial proportion of residents in their homes, and in their living environment more in general. In view of reducing the number of people affected by environmental noise exposure, the European Environmental Noise Directive (END) was adopted in 2002, geared towards the assessment and management of environmental noise. Over the last decades it has become increasingly recognised that environmental noise exposure in the living environment may lead to adverse health effects. Annoyance and sleep disturbance, mainly related to road traffic noise, are considered to be the most prominent noise effects (WHO, 2011). For these effects exposure response relationships have been established (Miedema and Oudshoorn, 2001; Miedema and Vos, 2007). During the last decades, in laboratory studies, field studies and epidemiological studies, it has been studied if and how noise exposure may lead to further adverse health effects. Evidence for a relationship between long term exposure to noise and stress related health effects, including cardiovascular disease, is increasing (Babisch et al., 2008; WHO, 2011; Van Kempen and Babisch, 2012; Basner et al., 2013; Babisch, 2014

What motivates people, and when do they perform optimally at work? In this dissertation, a regulatory focus perspective is taken (RFT, Higgins, 1997) to provide answers to these important questions. The results of multiple studies, conducted in complex organizational environments are reported. In many of those environments, there is a clear preference for promotion oriented employees and leaders. Yet, many jobs contain both promotion and prevention tasks. The results show that the use of the prevention orientation contributes importantly to both individual and organizational performance.

The research presented in this PhD thesis has been motivated by the fact that the Netherlands, and the Randstad region in particular, are affected by the large transport flows and extensive operations of the logistics sector. These operations create welfare for those people who work in the sector, who own the companies, and for the Dutch and European societies as the whole. The strong transport and logistics sector has also negative impact on the public infrastructure, air pollution, greenhouse gas emissions, causes accidents and other negative effects on the societal welfare. The strength of the Dutch logistics sector, the benefits and negative effects that it brings, require a thorough understanding of the logistics systems at the regional level. A quantitative tool, which is capable of an analysis of freight flows via the logistics and distribution systems in an empirically valid way, would be of substantial help for the decision makers at the national and regional levels. The quantitative tool (or a model) should also be able to study the system in a scenario-wise way, such that the impact of certain changes in the system can be quantified, studied and assessed. The Dutch logistics system is complex, with a large number of various national and international players. Understanding the logistics system in a holistic way requires an appropriate degree of aggregation and abstraction, as it would be unpractical to study each company and each private decision maker in the Netherlands: there are too many for this approach to be feasible. Therefore, this research concentrates on regions, as opposed to the individual companies, and describes the transport demand patterns realized by the logistics systems, as opposed to optimization of those systems, see FIGURE 1.1 for a graphical positioning of the focus of this research. This research is also limited to the transport flows realized by the road transport mode. This thesis looks at the core product of the logistics sector: linking production and consumption together, or how the goods are shipped from the places where the they are produced to the places where they are consumed

In dit proefschrift wordt onderzocht in hoeverre beweeggames kunnen bijdragen aan de preventie van overgewicht bij 12- tot 16-jarigen. Uit het onderzoek blijkt dat dit soort games nog niet kunnen concurreren met de gangbare computergames en daarom niet aantrekkelijk genoeg zijn voor jongeren om naar over te stappen. Simons raadt de fabrikanten van de beweeggames dan ook aan om beweeggames aantrekkelijker te maken voor deze doelgroep door bijvoorbeeld meer kenmerken van de traditionele niet-actieve games er in te verwerken. Als beweeggames aantrekkelijker worden voor jongeren en beter kunnen concurreren met de games die zittend gespeeld worden, lijken ze veelbelovend om in te zetten voor gezondheidsbevordering. In deze games moeten de spelers namelijk bewegingen met het hele lichaam maken, zoals dansen, boksen of tennissen, om het spel te kunnen spelen. Op dit moment heeft het spelen van beweeggames echter nog geen positief effect op de preventie van gewichtstoename – jongeren grijpen nog het liefst naar de niet-actieve games. Als ouders beweeggames kopen voor hun gamende kinderen om ze actiever te krijgen, lijkt dit nu dus nog niet zo zinvol. Simons achterhaalde met een vragenlijst onder 373 jongeren van 12 tot en met 16 jaar hoeveel van hen beweeggames spelen en hoeveel tijd ze dit doen. Via een 24-uurs dagboekstudie bekeek ze vervolgens hoe het spelen van beweeggames samenhangt met andere activiteiten die samenhangen met de energiebalans: besteden jongeren die meer tijd besteden aan beweeggames ook meer tijd aan niet-actieve games? Besteden jongeren die meer tijd besteden aan beweeggames minder tijd aan andere beweegactiviteiten? In gesprekken met adolescenten kreeg Simons een beeld van hun mening over niet-actieve games en beweeggames. In een gecontroleerd en gerandomiseerd interventieonderzoek bij gamende adolescenten met overwegend een gezond gewicht werd gekeken naar de effecten van het aanreiken van beweeggames op overgewicht, op de tijd die zittend doorgebracht wordt en op het nuttigen van snacks en frisdrank. Hieruit bleek dat het aanreiken van beweeggames met een kleine aanmoediging om ze te spelen niet bijdraagt aan preventie van overmatige gewichtstoename. Wel zou het kunnen bijdragen aan het terugdringen van de tijd die jongeren zittend doorbrengen. Hoofdstuk 2 niet aanwezig in Proefschrift.

For South Asian adults lowered BMI cut-offs for overweight and obesity are recommended as these are more in agreement with their body composition (low muscle mass, high fat mass) and the considerably higher risk of cardiovascuar and metabolic disease. For South Asian children living in a Western country lowered BMI norms have not been established, nor other ethnic specific growth standards. The aims of this thesis are 1. to gain more insight into the normal physical growth of South Asian children 2. to develop South Asian specific height-for-age (0-21 years) and BMI-for-age (2-18 years) references, including BMI cut-offs. The studies in this thesis show that South Asian children are generally lighter and shorter than other ethnic groups. The mean birth weight is at 3012 grams around 450 grams lower than of Dutch babies and has remained unchanged for the past 35 years. In children 3-15 years thinness is highly prevalent and overweight prevalence is relatively low. Application of the developed height-for-age charts and lowered BMI cut-offs will expectedly lead to a better assessment of height and nutritional status (thinness, overweight) in this group. Consequently, thinness rates will be lower while overweight will be detected earlier, leading to earlier preventive interventions.

Het onderzoek beschrijft bevallingen van vrouwen met een ongecompliceerde zwangerschap in heel Nederland, begeleidt door eerstelijns verloskundigen. In de jaren 2000-2008 werden deze vrouwen steeds vaker tijdens de bevalling naar het obstetrische team in het ziekenhuis verwezen, voornamelijk vanwege niet-urgente redenen. Dit betekende ook een toename van obstetrische behandelingen zoals medicinale pijnbestrijding, stimulatie van de weeën, of continue elektronische monitoring van het ongeboren kind. Het bleek dat de veranderingen in de zorg niet gepaard gingen met andere uitkomsten voor het kind: in deze gezonde groep vrouwen bleef het risico op perinatale sterfte of lage Apgar scores onverminderd klein. Tegelijkertijd nam bij vrouwen die van hun eerste kind bevielen het aantal keizersneden toe. Bijkomende nadelen van deze veranderingen in de zorg zijn een toenemende versnippering van de zorg tijdens de bevalling door de verwijzingen van eerste naar tweede lijn, en een grotere kans op morbiditeit ten gevolge van de medische behandelingen. Positief is dat de toegankelijkheid tot pijnbestrijding tijdens de baring is verbeterd voor vrouwen. Opvallend waren de grote verschillen tussen verloskundigen praktijken in de mate waarin zij vrouwen tijdens de bevalling verwijzen naar het obstetrisch team. Verloskundigen lijken te verschillen in de wijze waarop zij beslissingen nemen tijdens de baring. Ook de samenwerking met het lokale ziekenhuis kan daarop van invloed zijn: ook ziekenhuizen verschillen sterk in verloskundig beleid, zo blijkt uit de Zorgbalans van het RIVM. Om optimale kwaliteit van de verloskundige zorg aan vrouwen met een normale zwangerschap te realiseren is het belangrijk dat de kansen op een normale bevalling worden geoptimaliseerd, en dat niet alleen wordt gelet op het terugdringen van babysterfte. Dit kan gerealiseerd worden binnen de eerste lijn, zonder grote veranderingen in de organisatie van de verloskundige zorg in Nederland. Wel kan de taak van de eerstelijns verloskundige eventueel worden uitgebreid om de continuïteit van zorg tijdens de bevalling te verbeteren. Net als in andere Europese landen, kan zij dan de begeleiding van haar cliënten langer voortzetten als behandelingen zoals pijnbestrijding nodig zijn in niet-urgente situaties.

Global greenhouse gas emissions, especially of CO2, have been increasing tremendously over the past century. This is known to cause not only an increase of temperature, but also a change in our climate. Along with a shift to renewable sources of energy, Carbon Capture and Storage is necessary to mitigate climate change. Power plants are the largest point source of CO2 emissions and therefore, capture of CO2 from such sources is a must. Post Combustion CO2 Capture (PCCC), and specifically absorption-desorption based technology is the preferred choice of technology for CO2 capture from flue gases. It has been extensively used in the oil and gas industry for gas treatment. Its application for CO2 capture from flue gases is not straightforward, mainly due to different flue gas composition and operating conditions. Other aspects such as solvent degradation, solvent emissions and corrosion become even more critical. In Chapter 1, the state-of-the-art in PCCC is explained with further details on the current knowledge and understanding of these aspects. In Chapter 2, the aspect of solvent ageing is studied over two test campaigns in a CO2 capture pilot plant using 30 wt.% MEA. Solvent degradation occurs via thermal and oxidative routes, with the latter being more prominent. Ammonia is known to be a major oxidative degradation product, while the remaining degradation products are known to be corrosive. Therefore, solvent degradation is expected to have a significant impact on the corrosion in the plant and the resulting emissions of ammonia. The link between these three parameters was confirmed using online monitoring probes. Moreover, an autocatalytic behaviour was observed resulting in an rapid increase of the solvent metal content and ammonia emissions. The solvent iron content was above 500 mg/kg, while the ammonia emissions exceeded 150 mg/m3 STP (STP; 0°C and 101.325 kPa). By correlating the process conditions to the underlying degradation and corrosion mechanisms, online monitoring tools can be used to assess and manage the lifetime of the solvent. Even if the state of the solvent is kept in check by reclaiming methods, there could be instances where ammonia emissions could increase. Therefore, it is necessary to have an end of pipe countermeasure for such emissions. Chapter 3 presents the results from a test using an acid wash scrubber for ammonia emissions in a pilot plant test campaign. Several parametric tests were conducted in order to test the efficiency of the acid wash. Moreover, the ammonia concentration in the gas inlet to the acid wash was increased artificially (~150 mg/m3 STP). The acid wash scrubber reduced ammonia emission to very low levels, below 5 mg/m3 STP and mostly below 1 mg/m3 STP. Moreover, the MEA content was also reduced to mostly below 1 mg/m3 STP. A comparison between a model made in Aspen Plus and the experimental results showed good agreement, with deviations only at pH above 5 to 6. Aerosol based emissions are known to be a concern in PCCC. In Chapter 4, the impact of flue gas particles such as soot and sulphuric acid aerosol droplets on solvent emissions was studied in a mobile CO2 capture plant. These tests confirmed that solvent emissions can be in the order of grams per m3 STP, which is several orders of magnitude higher than volatile emissions. The number concentration of these particles had a direct relation to the extent of emissions. Particle number concentrations in the range of 107-108 per cm3 led to emissions of MEA in the range of 600-1200 mg/m3 STP. In Chapter 5, further tests were performed on the same setup in order to assess the impact of operating conditions of the CO2 capture plant on aerosol based emissions. Increasing the temperature of the lean solvent resulted in lowering of the aerosol based emissions. However, the total solvent emission increased as a result of increased volatile emissions. Aerosol based emissions were observed also for AMP-Pz as the capture solvent. The pH of the lean solvent was decreased by lowering the stripper temperature and thereby, changing the CO2 loading of the solvent. This resulted in an increase in the aerosol based emissions as the activity of the amine increased in the solvent. As the CO2 content in the flue gas was reduced from 12.7 vol.% to 0.7 vol.%, a maximum in the emissions was observed between 6 and 4 vol.%. When a mixture of a slow reacting volatile amine, AMP, with a fast reacting non-volatile, taurate, was used, no aerosol based emissions were observed. This led to the important conclusion that in reactive absorption, along with supersaturation and particle number concentration, the reactivity of the amine plays an important role in aerosol based emissions. A Brownian Demister Unit (BDU), consisting of multiple polypropylene fibre elements, can be potentially used as a countermeasure for aerosol based emissions. This was tested in a pilot plant campaign using MEA and is discussed in Chapter 6. The BDU reduced emissions from about 85–180 mg/m3 STP to about 1–4 mg/m3 STP. A water wash was found to be effective against vapour based emissions, while the BDU was effective against aerosol based emissions. A BDU is not effective against ammonia emissions, as they are present in the vapour form. From the measured nitrosamines, NDELA was found to be in the solvent in the order of 2000 ng/ml, while in the water wash it was ca. 1 ng/ml. Gas phase nitrosamine concentrations were in the range of tens of ng/m3 STP. The BDU results in a significant additional pressure drop of ca. 50 mbar, for the configuration and type of BDU used here. This translated to an additional consumption of electricity by the blower in the range 26–52%. A system containing three distinct phases, gas, liquid and aerosol droplets, are complex to understand and model. In Chapter 7, a methodology is presented with which such a complicated system can be modelled in commercially available software such as Aspen Plus. The mass and energy exchanges are split into two distinct interactions, gas-liquid and gas-aerosol. Aerosol droplets are considered to be as bulk liquid without any direct interaction with the solvent. The different parameters that were varied were the CO2 concentration in the flue gas, temperature of the lean solvent and CO2 loading of the lean solvent. The resulting trends were in good agreement with the experimental results presented in Chapter 5. The model did not predict a maximum in the emissions as the CO2 content in the flue gas was varied. Although absorption desorption based process for CO2 capture is well known, several operating issues needs to be addressed for its application in PCCC, as evident in this thesis. It is important to monitor the degradation of the solvent and deploy appropriate methods at the right time, to minimize its detrimental effect on the corrosion of the plant and avoid high emissions of ammonia. Aerosol based emissions in a PCCC process is a serious issue. The experimental results, proposed mechanism and modelling methodology will enable the design of appropriate counter-measures against aerosol based emissions. It is recommended to devise appropriate strategy and innovative solutions based on the understanding of the various operational aspects of absorption-desorption based PCCC as presented in this thesis. This will increase the confidence level in the technology and lead to its successful deployment for mitigating climate change in the short term.

Het proefschrift beschrijft een studie naar de implementatie van de effectief gebleken ergotherapie-interventie voor mensen met dementie en hun mantelzorgers (EDOMAH). Middels een cluster-RCT werd de huidige post-HBO cursus voor ergotherapeuten vergeleken met een multi-professionele strategie gericht op ergotherapeuten, artsen en managers. De belangrijkste uitkomstmaten waren de adherentie van ergotherapeuten, het aantal verwijzingen naar EDOMAH en behandelresultaten bij cliënten en mantelzorgers. Daarnaast worden de resultaten van een procesevaluatie beschreven.

Due to an ageing society, an increasing retirement age, and high prevalence of chronic health problems among older persons, it is important to understand how older employees [with health problems] can work for longer and productively, often this is termed ‘sustainable employability’. This context brought about the research presented in this thesis, financed by the Department of Public Health of the Erasmus MC and the Netherlands Organisation for Applied Scientific Research TNO. The longitudinal questionnaire study ‘STREAM’ (Study on Transitions in Employment, Ability and Motivation) was the basis for the research (www.tno.nl/stream). STREAM was financed by the Dutch Ministry of Social Affairs and Employment. Due to an ageing society, an increasing retirement age, and high prevalence of chronic health problems among older persons, it is important to understand how older employees [with health problems] can work for longer and productively, often this is termed ‘sustainable employability’. This context brought about the research presented in this thesis, financed by the Department of Public Health of the Erasmus MC and the Netherlands Organisation for Applied Scientific Research TNO. The longitudinal questionnaire study ‘STREAM’ (Study on Transitions in Employment, Ability and Motivation) was the basis for the research (www.tno.nl/stream). STREAM was financed by the Dutch Ministry of Social Affairs and Employment. The main conclusions of the thesis are as follows: Highly engaged workers have greater improvement in physical and especially mental health during one-year follow-up than less engaged workers. Employees with an active, non-avoidant, coping style have a better work ability than employees with a non-active and avoidant coping style. Poor health adversely affects sustainable employability, this is especially the case for psychological health problems. However, favourable psychosocial work-related factors play an essential role, such as high autonomy and social support. These factors have a positive influence on sustainable employability, especially for workers with health problems. In conclusion, especially the promotion of favourable psychosocial work-related factors has the potential to greatly reduce that adverse health effects on sustainable employability.

International audience; After working for some time, developers commit their code changes to a version control system. When doing so, they often bundle unrelated changes (e.g., bug fix and refactoring) in a single commit, thus creating a so-called tangled commit. Sharing tangled commits is problematic because it makes review, reversion, and integration of these commits harder and historical analyses of the project less reliable. Researchers have worked at untangling existing commits, i.e., finding which part of a commit relates to which task. In this paper, we contribute to this line of work in two ways: (1) A publicly available dataset of untangled code changes, created with the help of two developers who accurately split their code changes into self contained tasks over a period of four months; (2) a novel approach, EpiceaUntangler, to help developers share untangled commits (aka. atomic commits) by using fine-grained code change information. EpiceaUntangler is based and tested on the publicly available dataset, and further evaluated by deploying it to 7 developers, who used it for 2 weeks. We recorded a median success rate of 91% and average one of 75%, in automatically creating clusters of untangled fine-grained code changes.

Large scale commercial introduction of CIGS photovoltaics (PV) requires modules with low costs, high efficiencies and long and predictable lifetimes. Unfortunately,knowledge about the lifetime of CIGS PV is limited, which is reflected in the results of field studies: degradation rates varying from 0% to about 4% per year have been observed. Since warrantees are given out that the modules will still yield 80% of their initial power after 20 years of field exposure, degradation rates are often too high as well as too unpredictable. In order to decreasing these degradation rates, knowledge about the degradation behaviour is very important. Knowledge about this degradation would also enable lower production costs: Since both field and accelerated laboratory tests have already shown that elevated humidity and temperature have a negative impact on CIGS PV, modules are laminated with barrier materials to keep the moisture out. For rigid modules, glass is an excellent barrier choice, but for flexible modules, expensive organic-inorganic multilayer coatings are often used. An intrinsically more stable CIGS solar cell would therefore also limit the barrier costs and facilitate the large scale market introduction of flexible CIGS PV. Therefore, I have focused in this work on the identification of de degradation mechanisms in thin film CIGS solar cells. Since these cells consist of at least five individual layers, that all influence each other and the degradation behaviour, various layers have also been studied individually. The knowledge obtained on these individual layers was then used to interpret the degradation behaviour of complete CIGS solar cells. Within this thesis, I propose the degradation mechanisms for the molybdenum back contact and the zinc oxide front contact as well as for complete Cu(In,Ga)Se2 solar cells. The study of these mechanisms has been executed by the exposure of samplesdeposited at different conditions to various accelerated lifetime testing. This was combined with extensive analysis of the samples before, during and after lifetime tests. These tests should give an indication about the long term field exposure of CIGS modules, but it should be mentioned that the validity of the comparison of laboratory testing on solar cells and field exposure on modules it still under discussion. The following tests have been used in this study. 1. Standard ‘damp heat’ – exposure of samples to 85oC and 85% relative humidity (RH). A thousand hours exposure to these standard conditions should be comparable to 20 years of field exposure in Miami (acceleration factor 175x). It should be noted that e.g. literature reported that the acceleration factors of these tests range from 10x to 700x, so this extrapolation should be treated with care. 2. ‘Hybrid degradation’ test (https://www.youtube.com/watch?v=Zmy5tb-2NK8) – a combination of damp heat exposure and AM 1.5 illumination. This allows simultaneous sample degradation with elevated temperature and humidity as well as illumination as loads, while the samples can also be insitu monitored, in order to learn more about the degradation behaviour. This setup has been designed and built within this study and attracted interest from external parties. Therefore, a consortium of three Dutch SMEs (Eternal Sun, Hielkema Testequipment and ReRa Solutions) is currently working on the commercialisation of this setup. 3. ‘Atmospheric species’ exposure – the cells and layers have been exposed to individual species occurring in air, like oxygen, nitrogen, carbon dioxide and water, and combination of these species. This helps the identification of the species that are responsible for the degradation of CIGS solar cells. This can lead to the identification of the degradation mechanisms and can allow optimisation of cost-effective and effective barrier materials. This setup has been designed and built as part of this study. Barrier materials are not used in any of these tests in order to even further accelerate the degradation rate. These tests, combined with extensive analysis of samples with among others IV, EQE, IV(T), EL, PL, lock-in thermography, 4PP, Hall, UV-VIS-NIR, Raman, XRD, SEM-EDX, HIM and SIMS, have led to the following conclusion on the degradation of CIGS solar cells and its constituents.

Background: Monitoring human growth is important. It is used to detection of abnormal growth trajectories of children, which may reflect nutritional problems or underlying illness. In a larger population, it can provide information about the health status of this population, for example the prevalence of overweight and obesity, or the mean height. In The Netherlands, national growth studies have been carried out every 10 to 15 years since 1955. These large, nationwide studies allow comparison of height and weight of Dutch children over time. Since 1997, the growth studies also focus on Turkish and Moroccan children living in The Netherlands. In 2009, the Fifth Dutch Growth Study was conducted. This thesis presents the main results. Methods: Data for the Fifth Dutch Growth Study were collected in 2008-2009. Trained health care professionals measured height and weight and recorded background characteristics of 10,030 Dutch children, 2,548 Turkish and 2,594 Moroccan children aged 0-21 years. Results: We found that the mean height of Dutch children has not changed since 1997. At age 21, Dutch boys were on average 183.8cm and Dutch girls 170.7cm. The mean height of Turkish and Moroccan children living in The Netherlands has increased since 1997, but they are still 6 to 7 cm shorter than their Dutch peers. In 2009, 14% of Dutch children aged 2-21 years was overweight, 2% obese and 0.6% severely obese. Compared to 1980, this was a twofold increase in the prevalence rate of overweight, a fivefold increase in obesity, and sevenfold increase in morbid obesity. This indicated that not only the proportion of children with overweight increased, but also the severity of this overweight. Among Moroccan children living in The Netherlands, the prevalence rates for overweight, obesity and severe obesity were two to three times higher than among the Dutch. The highest rates were found in Turkish children: two to five times higher than in Dutch children. Since 1980, the prevalence of thinness decreased in children of Dutch, Turkish and Moroccan origin. Conclusion: The Dutch are the world’s tallest population. The secular increase in height of Dutch children has come to a halt after 150 years. It is not completely clear why the Dutch have stopped growing taller. They might have reached the optimal height distribution. Alternatively, growth promoting environmental factors may have stabilized over the past decade, prevention the population from reaching its full growth potential. Despite efforts to reduce overweight and obesity figures in The Netherlands, childhood overweight and obesity rates in 2009 were higher than in 1997. The large differences in prevalence rates between children of Dutch, Turkish and Moroccan origin underline the need for tailored approaches targeting high risk groups in the battle against overweight an obesity.