593 research outputs found
Effects of flavour absorption on foods and their packaging materials
No full textKeywords: flavour absorption, scalping, packaging, food matrix, lldpe, ldpe, pp, pc, pet, pen,b-lactoglobulin, casein, pectin, cmc, lactose, saccharose, oil, modelling, storage, oxygen permeability, taste perception, sensory quality.Absorption of flavour compounds by linear low-density polyethylene (LLDPE) was studied in model systems representing differences in composition of the food matrix. Proteins,b-lactoglobuline and casein, were able to bind flavours, resulting in suppression of absorption of flavour compounds. Polysaccharides, pectin and carboxymethylcellulose, increased viscosity, and consequently decreased absorption. Disaccharides, lactose and saccharose, increased absorption, probably caused by a "salting out" effect of less apolar flavour compounds. The presence of a relative small amount of oil (50 g/l) decreased absorption substantially. Combined oily model systems, oil/casein and oil/pectin, showed a similar effect. The extent of absorption of flavour compounds by LLDPE was influenced by food components in the order: oil or fat >> polysaccharides and proteins > disaccharides. A model based on the effect of the polarity (log P) of flavour compounds and on their partitioning coefficients between food(matrix) and packaging material was developed. The model is able to predict absorption of flavour compounds from foods into LLDPE when lipids in the food matrix are the determining factor in flavour absorption. Results show that the model fits nicely with experimental data of real foods skim and whole milk.LLDPE, polypropylene (PP), polycarbonate (PC), polyethylene terephthalate (PET film and PET bottle) and polyethylene naphthalate (PEN) were immersed in a model flavour solution at different temperatures up to 14 days. The absorption rate and/or total amount of absorbed compounds increased considerably with increasing temperature. Depending on temperature, the total absorption of flavour compounds by the polyolefins (LLDPE and PP) was up to 2400 times higher than by the polyesters (PC, PET and PEN).The effect of absorbed flavour compounds on the oxygen permeability of low-density polyethylene (LDPE), PP, PC and PET was studied. Due to swelling of the polymers as a result of absorption of flavour compounds, LDPE and PP showed a significant increase of oxygen permeability of 21% and 130%. The oxygen permeability of PC showed a significant decrease of 11% due to occupation or blockage of the "micro-cavities" by the absorbed flavour compounds. Flavour absorption by PET did not affect the oxygen permeability significantly.The influence of flavour absorption LDPE, PC and PET on the taste perception of a flavour model solution and orange juice stored in glass bottles was studied with and without pieces of the respective plastic films. Although the content of flavour compounds between controls and polymer treated samples decreased substantially due to absorption, no significant effect on the taste perception of the model solution and orange juice were observed by triangular taste panel tests.</font
Being There VR Museum Trailer.
No full textMarnix S. van Gisbergen (project leader), Shima Rezaei Rashnoodi (project leader), Karlijn van Baal (Producer), Kevin Otto (Director), Leonie Palm (DOP), Adinda Berends (Audio), Joost Scheffers (Editing), Danny Linssen (Supervisor)
Structure from NMR and molecular dynamics: Distance restraining inhibits motion in the essential subspace
No full textWe address the question how well proteins can be modelled on the basis of NMR data, when these data are incorporated into the protein model using distance restraints in a molecular dynamics simulation. We found, using HPr as a model protein, that distance restraining freezes the essential motion of proteins, as defined by Amadei et al. [Amadei, A., Linssen, A.B.M. and Berendsen, H.J.C. (1993) Protein Struct. Funct. Genet., 17, 412-425]. We discuss how modelling protocols can be improved in order to solve this problem
Design, construction and commissioning of a technological prototype of a highly granular SiPM-on-tile scintillator-steel hadronic calorimeter
No full textAbstract
The CALICE collaboration is developing highly granular
electromagnetic and hadronic calorimeters for detectors at future
energy frontier electron-positron colliders. After successful tests
of a physics prototype, a technological prototype of the Analog
Hadron Calorimeter has been built, based on a design and
construction techniques scalable to a collider detector. The
prototype consists of a steel absorber structure and active layers
of small scintillator tiles that are individually read out by
directly coupled SiPMs. Each layer has an active area of
72 × 72 cm^2 and a tile size of
3 × 3 cm^2. With 38 active layers, the prototype
has nearly 22,000 readout channels, and its total thickness
amounts to 4.4 nuclear interaction lengths. The dedicated readout
electronics provide time stamping of each hit with an expected
resolution of about 1 ns. The prototype was constructed in
2017 and commissioned in beam tests at DESY. It recorded muons,
hadron showers and electron showers at different energies in test
beams at CERN in 2018. In this paper, the design of the prototype,
its construction and commissioning are described. The methods used
to calibrate the detector are detailed, and the performance achieved
in terms of uniformity and stability is presented
An efficient method for sampling the essential subspace of proteins
No full textA method is presented for a more efficient sampling of the configurational space of proteins as compared to conventional sampling techniques such as molecular dynamics. The method is based on the large conformational changes in proteins revealed by the ''essential dynamics'' analysis. A form of constrained dynamics is performed, forcing the system to move along some of the essential coordinates. This results in a broader sampling of the essential subspace than in a comparable conventional molecular dynamics simulation without constraints. The new sampling method (essential dynamics sampling) was applied to the histidine-containing phosphocarrier protein HPr. The results indicate that the essential dynamics sampling method produces physically allowed structures, as estimated by the evaluation of many geometrical properties. In addition, a study of the motions in the essential subspace reveals a diffusion-like behavior
Real-to-imaginary ratio of the forward elastic scattering amplitude at 550, 757, and 1077 MeV/c
No full textThe node: Relationship between the street and the built environment
No full textThe fascination started with the idea that a street is a gettering place for everyone. It is an open space where everybody can come and where people can meet and interact with each other. But is the street designed as a place for interaction? Or is it intended to get from one place to the other? Is the street a logistical way of working, to structure the city and the flow of people? Research has been done about the street, what is a street, and how do we experience a street? To create a better understanding of how streets are designed different street typologies around the world are analyzed. The exciting part about the streets is that they are everywhere, they already designed in a certain way during medieval times. Everage cities exist 1/3 out of streets. Can we see the street still as a public space, or is it occupied by the car? Looking at Rotterdam, 75% of the public space exists of streets, and are mainly occupied by vehicles. So what if we can see the street again as a public space, rather than a place for movement. This research focuses on how the connection between houses and the place for social interaction can increase in the street in relation to the built environment. The research question for this paper: How can the street become a public space through the design of a building? The research question will be tested in Rotterdam city center. Rotterdam is after the bombing design in a car-oriented way, which makes the topic very interesting. Besides of urbanization the big cities becomes denser and denser, this also includes Rotterdam. So the city needs to extend to household all those people. What you can see in Rotterdam is that the centre of the city is slowly moving more to the south. The city’s municipality created a high-rise strategy that will make it possible to house 50.000 more people/houses in the future. But through so, the number of buildings in the center is increasing and the amount of public space decreases. Streets are playing a significant role in the design of the of new households, and to keep the city livable. To test the research question through the design of a building, a specific location in Rotterdam’s center is chosen, called the Kop van Zuid. Through analyzing streets around the world and researching the different aspects of the street. Three main ambitions are defined, which will play an essential role in this project: designing a place for social interaction, establishing a human scale in the city center, and creating a connection between the street and the building.Architecture, Urbanism and Building Science
Energy Harvesting from Slender FRP Pedestrian Bridges
No full textThe Rotterdam municipality is constantly busy replacing old footbridges that have reached their lifetime. Lately, this is done using modern materials, such as fibre-reinforced polymers (FRP). FRP is a relatively light-weight material that has a high yield strength, which allows for aesthetically pleasing, very slender designs. Governing for such designs is often the dynamic behaviour of the bridge: its eigenfrequency may very well lie within the `critical range' of common footfall frequencies. If the step frequency of a pedestrian crossing the bridge lies near the eigenfrequency, a high dynamic amplification factor occurs: high vertical acceleration values for the bridge deck will occur, which means discomfort for the pedestrians.In this thesis, a sustainable solution to that problem was sought. Rather than using pile foundations to clamp the bridgeheads (and thereby increase the eigenfrequency out of the critical range), it was investigated whether the kinetic energy can be harvested from the bridge. Ideally, this both dampens the vibrations and provides free, sustainable energy.Several theoretical models were developed to describe the behaviour of an existing footbridge for which data is available. Adaptations to these models were made in the form of either extra dashpots or a tuned mass damper (TMD). In both cases, the dampers are regenerative, i.e. able to harvest energy.It was shown that adding a TMD provides the best energy harvesting performance. From a practical perspective, it has some advantages as well, such as universal applicability. The parameters in the single degree of freedom (SDOF) model were optimized for maximum energy harvesting while still keeping the vertical deck acceleration at reasonable levels. Finite element analysis largely confirmed these design choices, and showed that reducing the vibration levels is certainly possible with only a relatively small TMD. For a single person crossing at near-resonant footfall frequency only leads to a vertical acceleration of about 1.5 m/s. The amount of energy that can be harvested in such a way is small but non-negligible: about 26 Joules worth of energy is estimated to be gained by an `average' person crossing the bridge. This is taking into account system efficiency as well.A literature study concerning real-world energy harvesting systems was performed, and showed the possibility to closely emulate the theoretical behaviour that was assumed for the regenerative dashpots. This can be done using electromagnetic dampers in combination with proper power electronics design.Civil Engineering | Structural Engineerin
Adaptivity in program management: Identification of success factors for adaptive cooperation in program management
No full textLarge complex infrastructural projects and programs show cost overruns and delays. As these are often funded by governmental bodies, the cost overruns also have an economic impact for society. Where projects are focused on delivering their scope within time and budget, a program is focused on achieving a broader goal. To do so, a program consists of different projects that show interdependencies. This, complemented with many uncertainties and the program's long durations, make programs even more complex than projects. Program management needs to be flexible and able to adjust: adaptivity is a core characteristic of program management. An academic knowledge gap is seen on cooperation strategies that achieve adaptivity in programs. Therefore, this study focused on the identification of success factors for adaptive cooperation in programs. The different research methods have led to the identification of the following factor: mandate and formal structure that together determine the operational framework of teams and organisations. This factor influences the ability to be adaptive by setting rules for the teams. As adaptivity was often associated with social processes, this insight has an academic value and contributes to theory development on adaptivity in program management. In addition to this factor, factors focused on social processes can also influence the adaptivity. Program managers should define the mandate of teams and their formal structure before determining the social acts. This could enable adaptive cooperation in programs and reduce cost overruns and delays. This research provides a starting point for theory development on adaptive program management.Complex Systems Engineering and Management (CoSEM
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