1,251 research outputs found
Virtual prototyping of grabs: Co-simulations of discrete element and rigid body models
No full textThis dissertation has investigated whether a combination of DEM and MBD can be used for a reliable and accurate environment for predicting grab unloading performance. A grab is a type of bulk material handling equipment used for unloading materials such as coal and iron ore from vessel to shore. Both a grab and iron ore pellets have been modelled and coupled into a co-simulation. Particle stiffness reductions and coarse graining techniques have been developed and applied to reduce computational costs. The developed large scale coupled grab-pellets model compared very well with validation experiments conducted on a bulk terminal with a scissors grab. A demonstration of virtual prototyping of grabs showed that when this model is implemented in the grab design process significant improvements in grab performance can be achieved.Transport Engineering and Logistic
Improving the performance of the trolley supply chain with a focus on visibility.
No full textThe lack of visibility, significant investment and a presumption of fleet shrinkage falter the decision-making process of a Dutch airline. Five decision areas have been identified and for each decision area improvements strategies or alternatives have been designed. Selecting the best alternative per decision area is a multi-criteria decision making problem. Therefore, a more sophisticated method is required to support the decision-maker. For this problem the novel Best-Worst Multi-Criteria Decision Making Method (BWM) has been selected. The BWM has been successfully applied to select the best alternative per decision area. Next steps for the airline are the implementation of the chosen alternatives.SEPAMTransport & LogisticsTechnology, Policy and Managemen
Buckfast Abbey Archaeological Projects 1982-2016 Photographic Archive
No full textThis photographic archive is intended to augment the two publications on the abbey's archaeology by S.W. Brown (Proceedings of the Devon Archaeological Society 46, 1988, 13-89; and Devon Archaeological Society Occasional Paper 21, 2018) and the series of more detailed interim archive reports appearing on the ADS website (unpublished grey literature, accessible via author Stewart Brown)
Environment-insensitive two-photon ratiometric probe for in cellulo quantitative measurement of hydrogen peroxide
No full textThe quantitative analysis of a biological analyte directly through fluorescence imaging is essential in biomedical sciences but remains as a challenge owing to the environment-sensitive nature of fluorescence intensity. We show that a fluorescent hydrogen peroxide probe based on an in cellulo super-bright benzothiazolyl-benzocoumarin dye of which emission properties are insensitive to environmental changes offers a reliable and practical means for the quantitative analysis of hydrogen peroxide in cells and tissues directly through ratiometric imaging both under one-photon and two-photon excitation conditions. Different cellular hydrogen peroxide concentrations were determined for several cell lines and also for tumour and normal tissues. © 2021 The Author(s)11Nscopu
DEM particle upscaling for large-scale bulk handling equipment and material interaction
No full textPurpose: The development of bulk material handling equipment can be accelerated and made less expensive when testing of virtual prototypes is adopted. However, the modelling of a grab unloader requires a large volume (77 m3) of iron ore pellets, making the computational costs prohibitive. This paper investigates the extent to which the original particles can be substituted by larger, coarser grains. It is crucial that this particle upscaling does not alter the realistic behaviour of the simulated bulk material, nor its interaction with the bulk handling equipment. Approach: First, our coarse graining technique is explained and set out for the particle system at hand. The material behaviour is then characterized using three laboratory experiments (two angle of repose tests and a penetration test). Next, the results of simulations using two contact models with and without coarse graining with different scale factors are compared with the measured material behaviour and material-equipment interaction. This includes a comparison of the macrobehaviour of the bulk material and the tool interaction of coarser grains in a cutting and sliding process. After reaching a satisfactory verified solution on the laboratory scale, the material behaviour and interaction behaviour of a large-scale experiment are modelled. A simulation model of a grab unloader was used for validation of the chosen coarse graining approach. Findings: Using the scaling method presented, the macroscopic tests indicated consistent material behaviour, regardless of the chosen particle scale for two contactmodels. Scaling of the tool interaction process produced mixed results: the sliding process scaled consistently but the penetration process did not, most likely because it is significantly harder for coarser grains to move since they have to move further to the sides before the tool can pass, leading to higher normal forces and frictional forces on the tip. This inconsistency was compensated for by adjusting the wall friction coefficient in the tip of the penetration tool. Once this adapted coarse graining scheme was applied to the industrial-scale simulation of a grab unloader, it produced consistent particle-scale invariant results. Originality/value: This research is the first to show how coarse graining schemes for DEM simulations can be applied to large-scale bulk handling equipment involving dominance of material equipment interaction through penetration of the bulk material.Transport Engineering and Logistic
Molecular simulation of porous silica and B-alumina, using a scalable method for electrostatic interactions
No full textApplied Science
Computer simulations of colloidal suspensions - using an improved lattice-Boltzmann scheme
No full textApplied Science
On the Vitruvius of Cesare Cesariano
No full textThe focus of the essay is the Vitruvius edition of Cesare Cesariano (Como 1521). In particular Alessandro Rovetta wrote the sections on the editorial venture, the author, the translation, the lexica and the others sources
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