197,529 research outputs found
Voedingspatroon inventariseren
No full textEen voedingsinventarisatie kan bijdragen aan een gerichte voedingsbegeleiding op maat aan zwangere vrouwen. Marloes Derksen zocht in de literatuur naar een goede methode en naar de succesfactoren en barrières voor verloskundigen voor het geven van voedingsbegeleiding
What a pity, Pepper! How warmth in robot's language impacts reactions to errors during a collaborative task
Full text linkHoffmann L, Derksen M, Kopp S. What a pity, Pepper! How warmth in robot's language impacts reactions to errors during a collaborative task. In: HRI '20 Companion. ACM; 2020
How the magnitude and precision of pain predictions shape pain experiences
No full textThis publication package contains the files relevant for the publication Derksen, S.M.J.C, Konttinen, M., Myronenko, A., Seymour, B, Peerdeman, K.J. (2025). How the magnitude and precision of pain predictions shape pain experiences. European Journal of Pain, 29(1), e4769. doi: 10.1002/EJP.4769
Physical Aspects of Scraped Heat Exchanger Crystallizers: An Application in Eutectic Freeze Crystallization
No full textOne of the most important natural resources is fresh water. An unfortunate issue is however, the low availability and high demand of fresh water world-wide. From the total resources industry consumes about 20 % (1200 km3 yearly) [UN, 2007]. Industrial aqueous waste streams are therefore widely occurring, and their reuse becomes obligatory. For the recovery of water from dilute solutions multistage flash evaporation has been used for a long time. Reverse osmosis has proven to be a better alternative energy-wise, but is only a good option up to a solute concentration of about 5% above which the required pressure becomes too high. Conventional separation processes then become too expensive, and the residual often large waste streams are collected in ponds for further atmospheric drying or discharged in surface waters. For the treatment of more concentrated waste waters novel separation techniques therefore had to be developed where besides pure water, one or more pure inorganic or/and organic compounds were obtained, and where only a minor bleed stream remains for e.g. incineration or disposal. If indeed additionally one or more pure secondary raw materials can be produced for reuse or with a market value, such a separation process becomes economically feasible, and has a fair chance to be implemented. Eutectic Freeze Crystallization fits this requirement. In this crystallization process, that operates under eutectic conditions, pure ice and a second pure solid compound such as a salt or an acid, are simultaneously formed in case of a binary aqueous solution. For a more complex solution both pure ice and a mixture of compounds or in subsequent steps pure ice and one of the pure compounds are formed. Since ice floats to the top of the vessel and the other compound(s) present in the solution settle(s) to the bottom, the separation of the ice from the salts is facilitated. For the first prototypes of EFC crystallizers horizontal heat exchanger disks were used with holes to allow transportation of crystals through these holes during their segregation. EFC research continues to improve these designs and create new ones that minimize energy consumption by cutting energy losses to the environment, by increasing the heat fluxes by improved scraper designs, and recently by a radical change in heat exchanger geometry to improve the gravitational separation efficiency. This research focuses on physical phenomena that take place inside a common cooling crystallizer or inside a eutectic freeze crystallizer with a scraped heat exchanger surface with the aim to improve the scraper and the crystallizer design. One of the limiting factors for heat transfer in EFC processes is the formation of an insulating ice scale layer on the heat exchanger surface. In spite of the fact that scrapers are used to increase the heat transfer at the solution side, as well as to avoid the formation of an insulating ice scale layer, such scrapers are only effective in keeping the surface free from ice up to a certain temperature difference between the coolant and the solution. Earlier experiments have also demonstrated that for a horizontal heat exchanger surface that was evenly cooled underneath and evenly scraped at the top, scaling still preferentially starts at specific areas of the surface. Since ice scale formation at a certain spot on the heat exchanger surface is a consequence of the local temperature difference between the surface and the solution, this implies that the temperature at the surface differs locally. These variations in local temperatures are most likely induced by the flow field of the liquid insidethe crystallizer. In chapter 2 the temperature distribution across the horizontal heat exchanger surface at the bottom of the crystallizer was therefore measured by Liquid Crystal Thermometry and the local heat transfer distribution was calculated, while the fluid velocity inside the crystallizer was directly visualized by Stereoscopic PIV measurements. Liquid Crystal Thermometry revealed that the temperature on the heat exchanger surface was not uniformly distributed with temperature differences larger than 4 oC. Such differences are sufficient to explain the local variation in scaling tendency. Experimental results showed that in the middle of the scraped heat exchanger area the heat transfer is larger than around the shaft and close to the crystallizer wall. A strong secondary fluid flow in this crystallizer geometry was shown by stereoscopic PIV measurements. This flow pattern in the crystallizer is undoubtedly related to the differences in local heat flux, but the local heat fluxes could not directly be explained without a more detailed knowledge of the flow field close to the HE surface in the scraper region. For more detailed information on the flow pattern between the scrapers and thus more closely to the HE surface we had to rely on computational flow simulations, because this region was not accessible for PIV measurements. The turbulent flow in the total scraped HE crystallizer was therefore computationally resolved by Large Eddy Simulations using a Lattice Boltzmann scheme as reported in chapter 3. The simulations were validated by comparison with the PIV measurements performed previously. The LES results could explain the radial local heat transfer distribution along the HE surface. The local heat flux is higher in the middle region of the HE surface between the shaft and the outer wall because the fluid descends directly from the bulk, and its residence time near the HE surface is low. The lower local heat flux coefficient around the shaft is because the fluid is largely in solid body rotation. Close to the outside wall, a worse situation for heat flux is provoked by a static vortex that brings the fluid into a segregated area. These fluid flow results explain the local heat flux distribution measured by the TLC experiments. The shape of the scraper has a large impact on the turbulent fluid flow and related behavior of the scraped off ice particles in the direct vicinity of the HE surface. For a well-designed scraper the ice particles have to be transported up by the flow into the solution, and should not be redirected to the surface. In chapter 4 the liquid flow is visualized by dye injection and the particles are monitored directly for two types of commonly used scraper geometries. In conjunction with this experimental work direct numerical simulations of the two phase (solid-liquid) flow system were done. The particle-flow simulations used Lattice-Boltzmann discretization to solve the Navier-Stokes equations, and a Lagrangian approach to particle tracking. The simulation results were in qualitative agreement with the experimental visualizations of the same system, and provided good insight in the behaviour of the particles and the fluid flow induced by the two scraper geometries. Only drag and gravity forces acting on the particles were taken into account. Furthermore particles collided elastically with the HE surface and the walls defining the moving scraper. Our numerical approach without particle-particle collisions provided satisfactory results for the streamlined scraper because this shape did not accumulate the particles during its scraper action. For the vertically oriented scraper this simulation approach failed due to the build up of particles as could be observed from the visualisation experiments. It was therefore considered to be essential to include particle-particle collisions in order to predict accumulation of particles. When this was implemented the simulations were in agreement with the results of the visualization experiments. This type of simulations demonstrates that scrapers can be primarily designed based on numerical predictions. In chapter 5 a novel laboratory scale scraped cooled wall crystallizer with 130 liter capacity, two internal vertical cylindrical heat exchangers, and a total heat transfer area of 2.94 m2.m-3 crystallizer volume was designed. This crystallizer was tested for the recovery of Na2CO3.10H2O and ice from an industrial aqueous sodium carbonate/sodium bicarbonate solution. Compared with earlier designs this new design showed a high improvement in gravitational separation and ice scaling removal, and high heat transfer fluxes were achieved between the heat exchanger and the solution up to 10.5 kW.m-2. A cone installed in the top section effectively directed the ice crystals towards the outlet. The total solid content in the crystallizer was up to 36 wt% under steady state conditions, with average crystal sizes for ice of 100-200 mm and 50-120 mm for Na2CO3.10H2O. Impurities present in the solution, most likely the molybdate ions changed the habit of the Na2CO3.10H2O crystals from pseudo hexagonal for a pure system to lozenges. In Chapter 6 the performance was tested of a scaled up version of the new type of crystallizer with two heat exchanger modules stacked on top of each other. This crystallizer was directly connected to a continuous carbonate/bicarbonate containing blow-down stream in an industrial plant. The EFC process was effectively operated at a heat transfer of 5 kWm-2 without any ice scaling. Sodium carbonate decahydrate and pure ice were continuously produced at -3.8 oC by operating within the metastable zone width of bicarbonate. The crystals showed good filterability with a molybdenum content below 1 ppm. At -4.0 °C bicarbonate started to co-crystallize. The bimodal size distribution of the mixture resulted in poor filtration and purity of the salt product. Because of the necessity of an accurate phase diagram for the process described in chapter 6, the eutectic solubility lines of the ternary system NaHCO3-Na2CO3-H2O were determined experimentally and calculated with the extended UNIQUAC model in chapter 7. The extended UNIQUAC model describes the experimental data quite well. A special crystallizer was built and a procedure developed to accurately measure the eutectic solubility lines where ice and salt coexist in equilibrium with the solution. Anhydrous NaHCO3 and Na2CO3.10H2O were the only two types of crystals present in equilibrium with ice crystals in the ternary system. The anhydrous NaHCO3 crystals were needle shaped with lengths between 5 and 10 ?m, that were agglomerated into particles of about 100 ?m to 300 ?m, while the Na2CO3.10H2O were hexagonally shaped with sizes between 100 and 500 ?m. Chapter 8 focuses at the interface between a scale layer that grows upon a cooling surface and the solution. Scale formation on heat exchangers is not only happening in EFC processes or for ice, but is frequently encountered in many cooling crystallization processes. Crystallization is mostly an exothermic process. According to irreversible thermodynamics, the heat released during crystallization at the interface is distributed to both the liquid and solid phases which are in contact with the interface also for isothermal conditions. The excess entropy production rate for heat and mass transport into, out of and across the interface was used to define the fluxes and forces of the system. The method describes the interface as a separate (two-dimensional) phase in local equilibrium. Coupled heat and mass flux equations from non-equilibrium thermodynamics were defined for crystal growth and the temperature jump at the interface of the growing crystal. For theoretical and experimental simplicity the growth of MgSO4·7H2O on a cold surface was taken as an example. For a growth rate of 2.33×10-3 mol.m-2.s-1, around 20-30% of the heat of crystallization is calculated to be transferred back into the liquid side. The interface resistivity to mass transfer is 1.26×103 J.m2.s.K-1.mol-2, while the interface resistivity to heat transfer is 2.1×10-7 m2.K-1.W-1.Process and EnergyMechanical, Maritime and Materials Engineerin
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Wooncarrière van koopstarters met een Koopgarantwoning: Een onderzoek naar de wooncarrière van (oud-)bewoners van Koopgarantwoningen
No full textReal Estate & HousingArchitectur
sj-docx-1-jpx-10.1177_23743735231151532 - Supplemental material for A Qualitative Study Exploring Rehabilitant and Informal Caregiver Perspectives of a Challenging Rehabilitation Environment for Geriatric Rehabilitation
Full text linkSupplemental material, sj-docx-1-jpx-10.1177_23743735231151532 for A Qualitative Study Exploring Rehabilitant and Informal Caregiver Perspectives
of a Challenging Rehabilitation Environment for Geriatric Rehabilitation by Lian M J Tijsen, Els W C Derksen, Wilco P Achterberg and Bianca I Buijck in Journal of Patient Experience</p
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Untersuchung der Struktur und Interaktion mit allosterischen Modulatoren der Familie C GPCRs mit Hilfe von Sequenz-, Struktur- und Ligand-basierten Verfahren
No full textThis study focuses on structural features of a particular GPCR type, the family C GPCRs. Structure- and ligand-based approaches were adopted for prediction of novel mGluR5 binding ligand and their binding modes. The objectives of this study were: 1. An analysis of function and structural implication of amino acids in the TM region of family C GPCRs. 2. The prediction of the TM domain structure of mGluR5. 3. The discovery of novel selective allosteric modulators of mGluR5 by virtual screening. 4. The prediction of a ligand binding mode for the allosteric binding site in mGluR5. GPCRs are a super-family of structurally related proteins although their primary amino acid sequence can be diverse. Using sequence information a conservation analysis of family C GPCRs should be applied to reveal characteristic differences and similarities with respect function, folding and ligand binding. Using experimental data and conservation analysis the allosteric binding site of mGluR5 should be characterized regarding NAM and PAM and selective ligand binding. For further evaluation experimental knowledge about family A GPCRs as well as conservation between vertebrate rhodopsins was planned to be compared to results obtained for family C GPCRs (Section 4.1 Conservation analysis of family C GPCRs). Since no receptor structure is available for any family C GPCR, discussion of conserved sequence positions between family A and C GPCRs requires the prediction of a receptor structure for mGluR5 using a family A receptor as template. In order to predict the mGluR5 structure a sequence alignment to a GPCR template protein will have to be proposed and GPCR specific features considered in structure calculation (Section 4.1.4 Structure prediction of mGluR5). The obtained structure was intended to be involved in ligand binding mode prediction of newly discovered active molecules. For discovery of novel selective mGluR modulators several ligand-based virtual screening protocols were adapted and evaluated. Prediction models were derived for selection of possibly active molecules using a diverse collection of known mGluR binding ligands. For that purpose a data collection of known mGluR binding ligands should be established and this reference collection analyzed with respect to different ligand activity classes, NAM or PAM and selective modulators. The prediction of novel NAMs and PAMs using several combinations of 2D-, 3D-, pharmacophore or molecule shape encoding methods with machine learning techniques and similarity determining methods should be tested in a prospective manner (Section 4.2 Virtual screening for novel mGluR modulators). In collaboration with Merz Pharmaceuticals (Merz GmbH & Co. KGaA, Frankfurt am Main, Germany) the modulating effect of a few hundred molecules should be approved in a functional cell-based assay. With the objective to predict a binding mode of the discovered active molecules, molecule docking should be applied using the allosteric binding site of the modeled mGluR5 structure (Section 4.2.4 Modeling of binding modes). Predicted ligand binding modes are to be correlated to conservation profiles that had resulted from the sequence-based entropy analysis and information from mutation experiments, and shall be compared to known ligand binding poses from crystal structures of family A GPCRs.Im Rahmen dieser Arbeit wurden Konzepte zur Aufklärung struktureller und funktioneller Eigenschaften von G-Protein gekoppelten Rezeptoren (GPCR) der Familie C entwickelt und angewendet. Mit unterschiedlichen Methodiken der Bio- und Chemieinformatik orientiert an experimentellen Ergebnissen wurden Fragestellungen bezüglich des Funktionsmechanismus von GPCRs untersucht. In Verlauf wurde anhand verfügbarer experimenteller Daten aus Mutations- und Ligandenbindungsstudien ein Vergleich konservierter Bereiche der Rezeptor-Familien A und C angefertigt. Die Konserviertheitsanalyse stützte sich auf die Berechnung der Shannon-Entropie und wurde für ein multiples Sequenzalignment von Transmembrandomänen unterschiedlicher 96 Familie C GPCRs ermittelt. Konservierte Bereiche wurden mit Hilfe experimenteller Daten interpretiert und insbesondere zur Definition von Regionen in der allosterischen Bindetasche hinsichtlich Selektivität verwendet. Mit dem Ziel, neue selektive allosterische Modulatoren für den metabotropen Glutamatrezeptor des Typs fünf (mGluR5) zu finden, wurden mehrere Liganden-basierte Ansätze zur virtuellen Vorhersage der Aktivität von Molekülen entwickelt und getestet. Die dabei angewendete Strategie basierte auf der Kenntnis bereits bekannter Liganden, deren Strukturen und Aktivitätswerte für das Erstellen von Vorhersagemodelle genutzt werden konnten. Die prospektive Vorhersage stützte sich auf unterschiedliche Methoden zur Ähnlichkeitsberechnung und Arten der Molekülkodierung. Die Testung der Moleküle erfolgte hinsichtlich ihrer modulatorischen Wirkung am mGluR5. Die Art der Messung erfasste die Änderungen des Ca2+-Levels in der Zelle. mGluR5-bindende Modulatoren wurden zur Selektivitätsbestimmung einer Testung am mGluR1 unterzogen. Insgesamt konnten 8 von 228 getesteten Molekülen im Aktivitätsbereich unter 10μM ermittelt werden, darunter befand sich ein positiver allosterischer Modulator. Von den restlichen sieben negativen Modulatoren (NAM) waren fünf selektiv für mGluR5. Alle identifizierten NAMs wurden mittels molekularem Dockings auf mögliche Interaktion mit der Transmembrandomäne von mGluR5 untersucht. Die Bindungshypothese entsprach einer Überlagerung der gefundenen Moleküle und ihrer möglicher Interaktionspunkte. Exemplarisch am mGluR5 konnte somit die Eignung einer modellierten GPCR-Struktur für eine Hypothesengenerierung bezüglich Ligandenbindung und struktureller Zusammenhänge untersucht werden
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