Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Diffusion Decoupling in Binary Colloidal Systems Observed with Contrast Variation Multispeckle Diffusing Wave Spectroscopy
Higler, Ruben ; Frijns, Raoul A.M. ; Sprakel, Joris - \ 2019
Langmuir 35 (2019)17. - ISSN 0743-7463 - p. 5793 - 5801.

In the study of colloidal glasses, crystallization is often suppressed by leveraging size polydispersity, ranging from systems where particle sizes exhibit a continuous distribution to systems composed of particles of two or more distinct sizes. The effects of the disparities in size of the particles on the colloidal glass transition are not yet completely understood. Especially, the question of the existence of a decoupled glass transition between the large and small population remains. In order to measure colloidal dynamics on very long time scales and to disentangle the dynamics of the two populations, we employ contrast variation multispeckle diffusing wave spectroscopy. With this method, we aim to analyze the effect of size ratio, a = r PS /r pNIPAM , on particle dynamics near the glass transition of a binary colloidal system. We find that both for long-time (α-) and short-time (β-) relaxation, the dynamics of the small particles either completely decouple from the large ones (a = 0.2), moving freely through a glassy matrix, or are identical to the dynamics of the larger-sized population (a = 0.37 and 1.44). For a size ratio of 0.37, we find a single-glass transition for both particle populations. The postulated double-glass transition in simulations and theory is not observed.

Referenties en maatlatten voor natuurlijke watertypen voor de Kaderrichtlijn Water 2021-2027
Altenburg, W. ; Arts, G. ; Baretta-Bekker, J.G. ; Berg, M.S. van den; Broek Broek, T. van den; Buskens, R. ; Bijkerk, R. ; Coops, H.C. ; Dam, H. van; Ee, G. van; Evers, C.H.M. ; Franken, R. ; Higler, B. ; Ietswaart, T. ; Jaarsma, N. ; Jong, D.J. de; Joosten, A.M.T. ; Klinge, M. ; Knoben, R.A.E. ; Kranenbarg, J. ; Loon, W.M.G.M. van; Noordhuis, R. ; Pot, R. ; Twisk, F. ; Verdonschot, P.F.M. ; Vlek, H. ; Backx, J.J.G.M. ; Beers, M. ; Buijse, A.D. ; Duursema, G. ; Fagel, M. ; Leeuw, J. de; Molen, J. van der; Nijboer, R.C. ; Postma, J. ; Vriese, T. ; Duijts, R. ; Hartholt, J.G. ; Jager, Z. ; Stikvoort, E.C. ; Walvoort, D. - \ 2018
Amersfoort : Stowa (Stowa rapport 2018-49) - ISBN 9789057738135 - 481
Apparent strength versus universality in glasses of soft compressible colloids
Higler, Ruben ; Sprakel, Joris - \ 2018
Scientific Reports 8 (2018)1. - ISSN 2045-2322

Microgel colloids, solvent swollen hydrogel particles of microscopic size, are in osmotic equilibrium with their surroundings. This has a profound effect on the behaviour of dense solutions of these polymeric colloids, most notably their ability to swell and deswell depending on the osmotic pressure of the system as a whole. Here we develop a minimal simulation model to treat this intrinsic volume regulation in order to explore the effects this has on the properties of dense solutions close to a liquid-solid transition. We demonstrate how the softness dependent volume regulation of particles gives rise to an apparent change in the fragility of the colloidal glass transition, which can be scaled out through the use of an adjusted volume fraction that accounts for changes in particle size. Moreover, we show how the same model can be used to explain the selective deswelling of soft microgels in a crystalline matrix of harder particles leading to robust crystals free of defects. Our results not only highlight the non-trivial effects of osmotic regulation in governing the apparent physics of microgel suspensions, but also provides a platform to efficiently account for particle deswelling in simulations.

Law & disorder : the unusual case of weak colloidal solids
Higler, Ruben Frederik - \ 2018
Wageningen University. Promotor(en): Jasper van der Gucht, co-promotor(en): Joris Sprakel. - Wageningen : Wageningen University - ISBN 9789463438698 - 219
Linking slow dynamics and microscopic connectivity in dense suspensions of charged colloids
Higler, Ruben ; Krausser, Johannes ; Gucht, Jasper Van Der; Zaccone, Alessio ; Sprakel, Joris - \ 2018
Soft Matter 14 (2018)5. - ISSN 1744-683X - p. 780 - 788.
The quest to unravel the nature of the glass transition, where the viscosity of a liquid increases by many orders of magnitude, while its static structure remains largely unaffected, remains unresolved. While various structural and dynamical precursors to vitrification have been identified, a predictive and quantitative description of how subtle changes at the microscopic scale give rise to the steep growth in macroscopic viscosity is missing. It was recently proposed that the presence of long-lived bonded structures within the liquid may provide the long-sought connection between local structure and global dynamics. Here we directly observe and quantify the connectivity dynamics in liquids of charged colloids en route to vitrification using three-dimensional confocal microscopy. We determine the dynamic structure from the real-space van Hove correlation function and from the particle trajectories, providing upper and lower bounds on connectivity dynamics. Based on these data, we extend Dyre's model for the glass transition to account for particle-level structural dynamics; this results in a microscopic expression for the slowing down of relaxations in the liquid that is in quantitative agreement with our experiments. These results indicate how vitrification may be understood as a dynamical connectivity transition with features that are strongly reminiscent of rigidity percolation scenarios.
Doping colloidal bcc crystals - interstitial solids and meta-stable clusters
Higler, Ruben ; Sprakel, Joris - \ 2017
Scientific Reports 7 (2017). - ISSN 2045-2322 - 13 p.

The addition of a small amount of dopant impurities to crystals is a common method to tune the properties of materials. Usually the doping grade is restricted by the low solubility of the dopants; increasing the doping concentration beyond this solubility limit leads to supersaturated solutions in which dopant clusters dominate the material properties, often leading to deterioration of strength and performance. Descriptions of doped solids often assume that thermal excitations of the on average perfect matrix are small. However, especially for bcc crystals close to their melting point it has recently become clear that the effects of thermal disorder are strong. Here we study the doping of weak bcc crystals of charged colloids via Brownian dynamics simulations. We find a complex phase diagram upon varying the dopant concentration. At low dopant concentrations we find an interstitial solid solution. As we increase the amount of dopants a complex meta-stable liquid-in-solid cluster phase emerges. Ultimately this phase becomes meta-stable with respect to macroscopic crystal-crystal coexistence. These results illustrate the complex behaviour that emerges when thermal excitations of the matrix drive impure crystals to a weak state.

Linking Particle Dynamics to Local Connectivity in Colloidal Gels
Doorn, Jan Maarten Van; Bronkhorst, Jochem ; Higler, Ruben ; De Laar, Ties Van; Sprakel, Joris - \ 2017
Physical Review Letters 118 (2017)18. - ISSN 0031-9007
Colloidal gels are a prototypical example of a heterogeneous network solid whose complex properties are governed by thermally activated dynamics. In this Letter we experimentally establish the connection between the intermittent dynamics of individual particles and their local connectivity. We interpret our experiments with a model that describes single-particle dynamics based on highly cooperative thermal debonding. The model, in quantitative agreement with experiments, provides a microscopic picture for the structural origin of dynamical heterogeneity in colloidal gels and sheds new light on the link between structure and the complex mechanics of these heterogeneous solids.
Referenties en maatlatten voor natuurlijke watertypen voor de kaderrichtlijn water 2015-2021 ; 2e dr.
Altenburg, W. ; Arts, G. ; Baretta-Bekker, J.G. ; Berg, M.S. van den; Broek, T. van den; Buskens, R. ; Bijkerk, R. ; Coops, H.C. ; Dam, H. van; Ee, G. van; Evers, C.H.M. ; Franken, R. ; Higler, B. ; Ietswaart, T. ; Jaarsma, N. ; Jong, D.J. de; Joosten, A.M.T. ; Klinge, M. ; Knoben, R.A.E. ; Kranenbarg, J. ; Loon, W.M.G.M. van; Noordhuis, R. ; Pot, R. ; Twisk, F. ; Verdonschot, P.F.M. ; Vlek, H. ; Wolfstein, K. ; Backx, J.J.G.M. ; Beers, M. ; Buijse, A.D. ; Duursema, G. ; Fagel, M. ; Leeuw, J. de; Molen, J. van der; Nijboer, R.C. ; Postma, J. ; Vriese, T. ; Molen, D.T. van der; Herpen, F.C.J. van; Nieuwerburgh, L.L.J. van - \ 2016
Amersfoort : Stowa (Stowa rapport 2012-31) - 466
In het najaar van 2012 werd een geactualiseerde versie van het document Referenties en maatlatten voor natuurlijke watertypen voor de Kaderrichtlijn Water 2015-2021 vastgesteld. Uit het gebruik van deze maatlatten en het programmeren van de Aquokit Biologie (webservice voor toetsen van ecologische kwaliteit met deze maatlatten ontwikkeld door het InformatieHuis Water) bleek dat er correcties en verduidelijkingen nodig waren om te zorgen voor een juiste en consistente toepassing van de maatlatten. Deze correcties en verduidelijkingen zijn doorgevoerd in deze tweede druk. In bijlage 14 is een overzicht opgenomen van de aanpassingen in de maatlat ten opzichte van de eerst druk.
Anomalous dynamics of interstitial dopants in soft crystals
Tauber, Justin ; Higler, Ruben ; Sprakel, Joris - \ 2016
Proceedings of the National Academy of Sciences of the United States of America 113 (2016)48. - ISSN 0027-8424 - p. 13660 - 13665.
Anomalous dynamics - Crystals - Doping

The dynamics of interstitial dopants govern the properties of a wide variety of doped crystalline materials. To describe the hopping dynamics of such interstitial impurities, classical approaches often assume that dopant particles do not interact and travel through a static potential energy landscape. Here we show, using computer simulations, how these assumptions and the resulting predictions from classical Eyring-type theories break down in entropically stabilized body-centered cubic (BCC) crystals due to the thermal excitations of the crystalline matrix. Deviations are particularly severe close to melting where the lattice becomes weak and dopant dynamics exhibit strongly localized and heterogeneous dynamics. We attribute these anomalies to the failure of both assumptions underlying the classical description: (i) The instantaneous potential field experienced by dopants becomes largely disordered due to thermal fluctuations and (ii) elastic interactions cause strong dopant-dopant interactions even at low doping fractions. These results illustrate how describing nonclassical dopant dynamics requires taking the effective disordered potential energy landscape of strongly excited crystals and dopant-dopant interactions into account.

Discontinuous nature of the repulsive-to-attractive colloidal glass transition
Laar, T. van de; Higler, R. ; Schroën, K. ; Sprakel, J. - \ 2016
Scientific Reports 6 (2016). - ISSN 2045-2322

In purely repulsive colloidal systems a glass transition can be reached by increasing the particle volume fraction beyond a certain threshold. The resulting glassy state is governed by configurational cages which confine particles and restrict their motion. A colloidal glass may also be formed by inducing attractive interactions between the particles. When attraction is turned on in a repulsive colloidal glass a re-entrant solidification ensues. Initially, the repulsive glass melts as free volume in the system increases. As the attraction strength is increased further, this weakened configurational glass gives way to an attractive glass in which motion is hindered by the formation of physical bonds between neighboring particles. In this paper, we study the transition from repulsive-to-attractive glasses using three-dimensional imaging at the single-particle level. We show how the onset of cage weakening and bond formation is signalled by subtle changes in local structure. We then demonstrate the discontinuous nature of the solid-solid transition, which is marked by a critical onset at a threshold bonding energy. Finally, we highlight how the interplay between bonding and caging leads to complex and heterogeneous dynamics at the microscale.

Substitutional impurity-induced vitrification in microgel crystals
Higler, R. ; Appel, J. ; Sprakel, J.H.B. - \ 2013
Soft Matter 9 (2013). - ISSN 1744-683X - p. 5372 - 5379.
medium-range order - metallic glasses - liquids - spheres - scattering - colloids - packing
We study the effect of larger substitutional impurities on the structure of soft microgel crystals. At the size ratio we employ, rsmall/rlarge = 0.67, we observe the unexpected co-crystallisation of the large impurities with the base crystal, at low fractions of impurity particles. A single impurity takes the place of 4 tetrahedrally coordinated small particles within the lattice. However, as this is accompanied by local deformations of the particles, this distortion-minimizing structure transforms into a random surrounding of the impurity particle at higher fractions of large substitutional impurities. The distortions in the lattice become longer ranged through this transformation, and ultimately result in vitrification of the sample
Referenties en maatlatten voor natuurlijke watertypen voor de kaderrichtlijn water 2015-2021
Altenburg, W. ; Molen, D.T. van der; Arts, G.H.P. ; Franken, R.J.M. ; Higler, L.W.G. ; Verdonschot, P.F.M. ; Keizer-Vlek, H.E. ; Leeuw, J.J. de; Molen, J.S. van der; Nijboer, R.C. - \ 2012
Amersfoort : Stowa (Rapport / STOWA 2012 31) - ISBN 9789057735691 - 378
waterkwaliteit - indicatoren - oppervlaktewater - ecologie - kaderrichtlijn water - kwaliteitsnormen - water quality - indicators - surface water - ecology - water framework directive - quality standards
Dit rapport is een geactualiseerde versie van ‘Referenties en maatlatten voor natuurlijke watertypen voor de Kaderrichtlijn Water’. Het is het resultaat van een evaluatie van de maatlatten in de aanloop naar de tweede generatie Stroomgebiedbeheerplannen (2015-2021) en van een harmonisatie met de beoordelingsmethoden in het buitenland. Deze versie dient te worden gebruikt voor de doelafleiding en toestandsbepaling voor deze tweede generatie. De aanpassingen zijn voorbereid door teams van technisch specialisten en afgestemd binnen de werkgroep Ecologische Maatlatten, met vertegenwoordigers van waterschappen, provincies, het Ministerie van I&M en de STOWA. De aanpassing van de vissenmaatlat is afgestemd met Sportvisserij Nederland.
A two-year study of Trichoptera caught on light in the Kaaistoep (The Netherlands).
Higler, L.W.G. ; Spijkers, H. ; Wielink, P. van - \ 2008
Entomologische Berichten 68 (2008)5. - ISSN 0013-8827 - p. 175 - 181.
trichoptera - dispersie - natuur - noord-brabant - dispersion - nature
A screen and light source were operated at a fixed place in the Kaaistoep, a nature reserve near the city of Tilburg (province Noord-Brabant, TheNetherlands). Some 75 nights per year have been spent catching insects by hand, and among these many caddis flies (Trichoptera). We collected and identifïed caddis flies during 2005 and 2006. In both years together more than 16,000 specimens were caught, comprising 52 species, including quite some rare and unexpected species. Flight periods could be constructed, which sometimes showed great difference between the two years. Weather conditions are likely to be responsible for these differences.
Een kokerjuffer op het droge
Higler, B. - \ 2008
In: Passie voor kleine beestjes, 33,3 jaar Stichting EIS-Nederland / Kleukers, R., Berg, M., van Strien, W., Leiden : European Invertebrate Survey - Nederland - ISBN 9789076261065 - p. 54 - 55.
Processes influencing aquatic fauna
Gore, J.A. ; Mead, J. ; Penczak, T. ; Higler, L. ; Kemp, J. - \ 2008
In: Ecohydrology. Processes, models and case studies / Harper, D., Zalewski, M., Pacini, N., Wallingford : CABI - ISBN 9781845930028 - p. 62 - 87.
Nacht in de heemtuin.
Keuchenius, F. ; Higler, B. ; Verboom, B. - \ 2008
In: Dierenleven in de Londotuin. Amerongen : Vereniging voor Dorp en Natuur Amerongen - Leersum - p. 41 - 43.
Verspreidingsatlas Nederlandse kokerjuffers (Trichoptera)
Higler, L.W.G. - \ 2008
Leiden : European Invertebrate Survey - Nederland - ISBN 9789076261058 - 248
trichoptera - zoögeografie - dierecologie - habitats - nederland - zoogeography - animal ecology - netherlands
Omdat jarenlang sprake was van waterverontreiniging, is de soort afgenomen. Van kokerjuffers zijn er thans 181 soorten bekend; door verder onderzoek wordt een stijging van dat aantal verwacht
Schrijvertjes en schaatsenrijders.
Higler, B. - \ 2007
In: Dierenleven in de Londotuin. Amerongen : Vereniging voor Dorp en Natuur Amerongen - Leersum - p. 29 - 31.
Life cycles of some stagnant water caddis flies
Higler, B. - \ 2007
Lauterbornia : internationale Zeitschrift für Faunistik und Floristik der Binnengewässer Europas 61 (2007). - ISSN 0935-333X - p. 35 - 42.
Some rare and new caddis flies recorded for the Netherlands (Trichoptera)
Wiggers, R. ; Hoek, T.H. van den; Maanen, B. van; Higler, L.W.G. ; Kleef, H. van - \ 2006
Nederlandse Faunistische Mededelingen 25 (2006). - ISSN 0169-2453 - p. 53 - 68.
trichoptera - zoögeografie - waterdieren - aquatic animals - zoogeography
Since Higler published his list of extinct and endangered caddis fly species in 1995 a number of new and rare species have been recorded for The Netherlands
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