Onderzoek naar de invloed van plant- en oogsttijdstip, bewaartemperatuur en -duur op de bewaarbaarheid van groene savooie kool

Het Sprenger Instituut geeft een advies voor de bewaarmethode van groene savooie kool. Volgens deze bewaarmethode kan groene savooie kool vier maanden bewaard worden. Om tot nog betere bewaarresultaten te komen werd door het Sprenger Instituut en Proeftuin Zwaagdijk een bewaarproef ingezet. Men onderzocht wat het optimale plant- en oogsttijdstip en wat de optimale bewaartemperatuur was in relatie tot de bewaarbaarheid van groene savooie kool. Ook werd nagegaan wat de maximale bewaarduur was

Structure of nanoparticles embedded in micellar polycrystals

We investigate by scattering techniques the structure of water-based soft composite materials comprising a crystal made of Pluronic block-copolymer micelles arranged in a face-centered cubic lattice and a small amount (at most 2% by volume) of silica nanoparticles, of size comparable to that of the micelles. The copolymer is thermosensitive: it is hydrophilic and fully dissolved in water at low temperature (T ~ 0{\deg}C), and self-assembles into micelles at room temperature, where the block-copolymer is amphiphilic. We use contrast matching small-angle neuron scattering experiments to probe independently the structure of the nanoparticles and that of the polymer. We find that the nanoparticles do not perturb the crystalline order. In addition, a structure peak is measured for the silica nanoparticles dispersed in the polycrystalline samples. This implies that the samples are spatially heterogeneous and comprise, without macroscopic phase separation, silica-poor and silica-rich regions. We show that the nanoparticle concentration in the silica-rich regions is about tenfold the average concentration. These regions are grain boundaries between crystallites, where nanoparticles concentrate, as shown by static light scattering and by light microscopy imaging of the samples. We show that the temperature rate at which the sample is prepared strongly influence the segregation of the nanoparticles in the grain-boundaries.Comment: accepted for publication in Langmui

A Multi-Platform Flow Device for Microbial (Co-) Cultivation and Microscopic Analysis

Novel microbial cultivation platforms are of increasing interest to researchers in academia and industry. The development of materials with specialized chemical and geometric properties has opened up new possibilities in the study of previously unculturable microorganisms and has facilitated the design of elegant, high-throughput experimental set-ups. Within the context of the international Genetically Engineered Machine (iGEM) competition, we set out to design, manufacture, and implement a flow device that can accommodate multiple growth platforms, that is, a silicon nitride based microsieve and a porous aluminium oxide based microdish. It provides control over (co-)culturing conditions similar to a chemostat, while allowing organisms to be observed microscopically. The device was designed to be affordable, reusable, and above all, versatile. To test its functionality and general utility, we performed multiple experiments with Escherichia coli cells harboring synthetic gene circuits and were able to quantitatively study emerging expression dynamics in real-time via fluorescence microscopy. Furthermore, we demonstrated that the device provides a unique environment for the cultivation of nematodes, suggesting that the device could also prove useful in microscopy studies of multicellular microorganisms

Parallelized edge-based droplet generation (EDGE) devices

We here report on three parallelized designs of the new edge-based droplet generation mechanism, which, unlike existing mechanisms, produces many equally sized droplets simultaneously at a single droplet formation unit. Operation of the scaled-out systems is straight forward; only the oil inlet pressure has to be controlled to let all the units produce oil droplets, given certain basic design constraints. For systems with a typical nozzle depth of 1.2 µm, the mean droplet diameter is 7.5 µm and the coefficient of variation is below 10%. The number of droplets that is formed per unit can easily be increased by increasing the length of the unit. The stable pressure range in which monodisperse droplets are formed can be extended by small adjustments to the design. Overall, the EDGE devices are simple in design and robust in use, making them suitable for massive outscalin

Nanofiltration of multi-component feeds. Interactions between neutral and charged components and their effect on retention

Membrane characterization and modeling of membrane processes are essential steps in the development and implementation of new membrane filtration processes. The generalized Maxwell-Stefan equation is frequently used to describe, these processes. However, predictive modeling on the basis of characterization experiments using single solutes is still troublesome in a lot of cases. Consequently, a better understanding of the effect of the interaction between different components on the membrane separation characteristics is required. In this work, four well-known commercially available membranes, Desal 5DK, Desal 5DL Desal G5, NTR-7450. and a newly introduced membrane NF have been characterized. The pore radii of these membranes determined from glucose retention experiments increase in the following sequence: Desal 5DK approximate to NF <Desal 5DL <Desal G5 <NTR-7450. The pore radii and effective membrane thickness determined on the basis of glycerin experiments are within 6% of those determined using glucose. The presence of salt ions, especially of those for which the membranes show low retention. leads to reduction of the retention of neutral components (glucose). The retention reduction, at maximum 10% (absolute) in this study, depends on the membrane selected. For NF and Desal 5DK a high glucose retention drop coincides with a high concentration of the anion salt (Cl-) ions in the permeate, independent of the cation salt ion used. This phenomenon can be explained by, several hypotheses. One of these. supported by generalized Maxwell-Stefan model calculations, is that the presence of a pore size distribution leads to the observed shift in selectivity. In the presence of salt ions in the pores. the flux through small pores is reduced to a larger extent than that in bigger pores. Consequently, the retention for glucose drops and a shift in the apparent pore radius is determined. Regardless of the mechanism that causes the reduction Of the glucose retention, it is essential that this effect is incorporated in predictive models for nanofiltration to predict the loss of organic components to the permeate sufficiently accurately. since this loss may affect permeate disposal costs or product yield. (C) 2004 Elsevier B.V. All rights reserved

Chitin Nanocrystal Hydrophobicity Adjustment by Fatty Acid Esterification for Improved Polylactic Acid Nanocomposites

Bioplastics may solve environmental issues related to the current linear plastic economy, but they need improvement to be viable alternatives. To achieve this, we aimed to add chitin nanocrystals (ChNC) to polylactic acid (PLA), which is known to alter material properties while maintaining a fully bio-based character. However, ChNC are not particularly compatible with PLA, and surface modification with fatty acids was used to improve this. We used fatty acids that are different in carbon chain length (C4–C18) and degree of saturation (C18:2). We successfully used Steglich esterification and confirmed covalent attachment of fatty acids to the ChNC with FTIR and solid-state 13C NMR. The morphology of the ChNC remained intact after surface modification, as observed by TEM. ChNC modified with C4 and C8 showed higher degrees of substitution compared to fatty acidswith a longer aliphatic tail, while particles modified with the longest fatty acid showed the highest hydrophobicity. The addition of ChNC to the PLA matrix resulted in brown color formation that was reduced when using modified particles, leading to higher transparency, most probably as a result of better dispersibility of modified ChNC, as observed by SEM. In general, addition of ChNCprovided high UV protection to the base polymer material, which is an additional feature that can be created through the addition of ChNC, which is not at the expense of the barrier properties, or the mechanical strength

A cascade microfiltration and reverse osmosis approach for energy efficient concentration of skim milk

To improve the efficiency of water removal from skim milk, a cascade membrane process of microfiltration and reverse osmosis (RO) was developed whereby skim milk was concentrated to 18% dry matter (DM) by RO at either 15 or 50 °C. The average flux of the RO process at 50 °C was 89% higher than that observed at 15 °C, linked to altered membrane surface fouling behaviour due to lower viscosity, higher cross-flow velocity and increased diffusivity of the solvent phase. In corollary, a ~57% energy reduction per unit volume of water removed was observed when the RO process was operated at 50 °C. Evaluation of the physicochemical properties of control (9% DM content skim milk) and RO retentates post-heating (at 80, 90 and120 °C) and post-evaporation (to 42% DM) demonstrated a clear relationship between heating at elevated DM contents and solution viscosity, an effect that was compounded at higher heating temperatures.</p

Microfluidic apparatus and method for generating a dispersion

Microcfluidic apparatus (1) and method for generating a dispersion. The apparatus comprises a droplet formation unit (3) comprising a feed opening (2) for supplying a to-be-dispersed phase first substance to the droplet formation unit, and an oblong droplet formation opening (14) for forming droplets of the to-be- dispersed phase first substance in a continuous phase second substance, the droplet formation opening having a first, smallest dimension W and a second, largest dimension L, wherein the second dimension L of the droplet formation opening is more than fifty times the first dimension W of the droplet formation opening. The droplet formation unit has a third dimension D in a direction from the feed opening to the droplet formation opening, wherein the third dimension D is more than two and a half times the first dimension W. The microfluidic apparatus further comprises a feed structure, in fluid communication with the feed opening for feeding the to-be-dispersed phase first substance to the droplet formation unit, wherein a flow resistance of the droplet formation unit is larger than a flow resistance of the feed structure

Microfluidic apparatus and method for generating a dispersion

Microcfluidic apparatus (1) and method for generating a dispersion. The apparatus comprises a droplet formation unit (3) comprising a feed opening (2) for supplying a to-be-dispersed phase first substance to the droplet formation unit, and an oblong droplet formation opening (14) for forming droplets of the to-be- dispersed phase first substance in a continuous phase second substance, the droplet formation opening having a first, smallest dimension W and a second, largest dimension L, wherein the second dimension L of the droplet formation opening is more than fifty times the first dimension W of the droplet formation opening. The droplet formation unit has a third dimension D in a direction from the feed opening to the droplet formation opening, wherein the third dimension D is more than two and a half times the first dimension W. The microfluidic apparatus further comprises a feed structure, in fluid communication with the feed opening for feeding the to-be-dispersed phase first substance to the droplet formation unit, wherein a flow resistance of the droplet formation unit is larger than a flow resistance of the feed structure