Browsing by Keyword "Consistency"
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Item Rheological behaviour of blueberry cloudy juice (Vaccinium corymbosum L.)(2002-03) Cepeda, E.; Hermosa, M.; Llorens, F.; Villarán, M. C.; Alimentación SostenibleThe rheological behaviour of blueberry cloudy juice (Vaccinium corymbosum L.), prepared from fresh berries, was studied as a function of solids concentration, in the range 25-61 °Brix, at different temperatures (5-50 °C), with a control rate (CR) rheometer. Cloudy juice was concentrated by vacuum evaporation, and solutions at other concentrations were prepared from the concentrate by adding the liquid collected as distillate. The juices were slightly thixotropic between 45 and 61°Brix. For lower concentrations, the thixotropy was low and could be easily eliminated by shearing. The power law model was applied to fit the pseudoplastic behaviour. The activation energy for flow, evaluated with the Arrhenius-Guzman equation, increased with solids concentration and ranged from 4.6 to 24 kJ gmol-1. A non-linear correlation, accounting for temperature and concentration effects on the consistency coefficient, was identified.Item Simultaneous remote haptic collaboration for assembling tasks(2008-01) Iglesias, Rosa; Casado, Sara; Gutiérrez, Teresa; García-Alonso, Alejandro; Yu, Wai; Marshall, Alan; PROMETAL; CIRMETALStand-alone virtual environments (VEs) using haptic devices have proved useful for assembly/disassembly simulation of mechanical components. Nowadays, collaborative haptic virtual environments (CHVEs) are also emerging. A new peer-to-peer collaborative haptic assembly simulator (CHAS) has been developed whereby two users can simultaneously carry out assembly tasks using haptic devices. Two major challenges have been addressed: virtual scene synchronization (consistency) and the provision of a reliable and effective haptic feedback. A consistency-maintenance scheme has been designed to solve the challenge of achieving consistency. Results show that consistency is guaranteed. Furthermore, a force-smoothing algorithm has been developed which is shown to improve the quality of force feedback under adverse network conditions. A range of laboratory experiments and several real trials between Labein (Spain) and Queen's University Belfast (Northern Ireland) have verified that CHAS can provide an adequate haptic interaction when both users perform remote assemblies (assembly of one user's object with an object grasped by the other user). Moreover, when collisions between grasped objects occur (dependent collisions), the haptic feedback usually provides satisfactory haptic perception. Based on a qualitative study, it is shown that the haptic feedback obtained during remote assemblies with dependent collisions can continue to improve the sense of co-presence between users with regard to only visual feedback.