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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    We will mail you new results for this query: keywords==diffusivity
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Photopyroelectric assessment of the thermal effusivity of fresh hen egg and of rehydrated egg powders
Szafner, G. ; Nemeth, C. ; Bicanic, D.D. ; Doka, O. - \ 2015
Journal of Thermal Analysis and Calorimetry 120 (2015)1. - ISSN 1388-6150 - p. 363 - 368.
conductivity - diffusivity - parameters - products - heat - spectroscopy - temperature - milk
The availability of thermo-physical data of foods and their constituents is of general importance to food industry. The thermal effusivity e is one among the relevant thermodynamical quantities. The latter is normally calculated from the relationship e = (¿¿c)½, where c is specific heat, ¿ is the density, and ¿ is the thermal conductivity. The necessity for performing the time consuming independent measurements of these three quantities is the major reason that the existing database with effusivity of foods is not very wide. This paper describes the application of the inverse photopyroelectric (IPPE) technique that allows the determination of effusivity from a single measurement. This approach was used to directly measure thermal effusivity of fresh egg yolk, egg white, and white/yolk blends. In addition, thermal effusivity of rehydrated egg powders (white, yolk, and the whole egg powder) has been measured and compared to that of the fresh hen egg. In case of the egg white, effusivity of rehydrated egg powders was practically the same as that of the fresh egg. However, the difference in effusivity between fresh egg yolk and rehydrated egg yolk, and between the blend of fresh egg and the rehydrated whole egg power was significant. Finally, thermal effusivity of rehydrated egg yolk, egg white, and the whole egg powder was determined as a function of dilution factor.
CO2 capture by biomimetic adsorption: enzyme mediated co2 absorption for post-combustion carbon sequestration and storage process
Russo, M.E. ; Olivieri, G. ; Salatino, P. ; Marzocchella, A. - \ 2013
Environmental Engineering and Management Journal (EEMJ) 12 (2013)8. - ISSN 1582-9596 - p. 1595 - 1601.
butanol production - inhibitor removal - mass-transfer - anhydrase ii - hydration - kinetics - dioxide - reactor - microreactor - diffusivity
The huge emission of greenhouse gases from fossil-fuelled power plants is emphasizing the need for efficient Carbon Capture and Storage (CCS) technologies. The biomimetic CO2 absorption in aqueous solutions has been recently investigated as a promising innovative alternative for post-combustion CCS. The carbonic anhydrase (CA) - a broad group of ubiquitous enzymes - may catalyse the CO2 hydration reaction and then to promote CO2 absorption rate into aqueous solutions. Nevertheless the research on this issue is quite active, the reliable designing of absorption units still requires more details. The present study proposes the design of a random packing absorption column operated with alkaline solvents supplied with CA. The height of the packed bed to fulfil the 80% of CO2 abatement from a flue gas stream was as large as 15-20 m. A comprehensive discussion of effects of operating conditions and of CA features on unit performance is reported.
Elke teler kan voor zijn gewas het juiste diffuse glas vinden (interview met Silke Hemming en Tom Dueck)
Bezemer, J. ; Dueck, T.A. ; Hemming, S. - \ 2013
Onder Glas 10 (2013)6/7. - p. 7 - 9.
glastuinbouw - teelt onder bescherming - diffuus glas - diffusiecoëfficiënt - coating - lichtdoorlating - besluitvorming - kwaliteit - diversiteit - kastechniek - greenhouse horticulture - protected cultivation - diffused glass - diffusivity - light transmission - decision making - quality - diversity - greenhouse technology
Het gebruik van diffuus glas heeft een positief effect op de teeltresultaten. Maar de teler die voor de investering wil kiezen, ziet verschillende vragen op zich afkomen. Want het ene diffuse glas is het andere niet. De teler moet de verschillen kennen en de effecten van diffuus glas op zijn gewas begrijpen. Daarna kan hij op zoek naar het glas van zijn keuze.
Moisture distribution in broccoli: measurements by MRI hot air drying experiments
Jin, X. ; Sman, R.G.M. van der; Gerkema, E. ; Vergeldt, F.J. ; As, H. van; Boxtel, A.J.B. van - \ 2011
Procedia Food Science 1 (2011). - ISSN 2211-601X - p. 640 - 646.
profiles - nmr - diffusivity - model - food - gel
The internal moisture distribution that arise in food products during drying, is a key factor for the retention of quality attributes. To reveal the course of moisture content in a product, internal moisture profiles in broccoli florets are measured by MRI imaging during drying experiments with controlled air flow and temperature. The 3D images concern a matrix size of 64×64×64 elements. Signal intensity is converted to product moisture content with a linear relationship, while taking a minimum detectable moisture content of 0.3 kg water/ kg dry matter into account. Moisture content as a function of time is presented for a 2D cross sectional area in the middle of a broccoli sample. The average moisture contents for the cross sectional area obtained from the MRI imaging are compared with spatial model simulations for the moisture distribution. In that model the effective diffusion coefficient is based on the Free Volume Theory. This theory has the advantage that the changed mobility of water in the product during drying is taken into account and the theory also predicts the moisture transport in the porous broccoli floret. Key parameters for the Free Volume Theory are estimated by fitting to the experimental MRI results and the effective diffusion coefficient is given as a function of the product water content.
Diffuus licht - wat is de optimale lichtverstrooiing?
Dueck, T.A. ; Poudel, D. ; Janse, J. ; Hemming, S. - \ 2009
Wageningen : Wageningen UR Glastuinbouw (Rapport / Wageningen UR Glastuinbouw 308) - 50
cucumis sativus - komkommers - lichtdoorlating - licht - diffusiecoëfficiënt - groei - gewasproductie - kassen - bedekkingsmaterialen - glastuinbouw - cucumbers - light transmission - light - diffusivity - growth - crop production - greenhouses - covers - greenhouse horticulture
Dit rapport beschrijft het verslag van een onderzoek naar de effecten van de mate van diffusiteit en lichttransmissie op de groei en productie van komkommers.
Mean-field stationary diffusion: polymers in steady-state systems
Scheinhardt-Engels, S.M. - \ 2004
University. Promotor(en): Gerard Fleer, co-promotor(en): Frans Leermakers. - [s.I.] : S.n. - ISBN 9085040612 - 165
polymeren - moleculaire structuur - membranen - diffusiecoëfficiënt - diffusieweerstand - polymers - molecular conformation - membranes - diffusivity - diffusion resistance
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