http://hdl.handle.net/2117/1750 2013-05-20T01:35:35Z http://hdl.handle.net/2117/19103 Title: Analysis of sedimentation and resuspension processes of aquaculture biosolids using an oscillating grid Authors: Masaló Llorà, Ingrid; Guadayol, Oscar; Peters, Francesc; Oca Baradad, Joan Abstract: Sedimentation and resuspension processes of aquaculture biosolids (non-ingested feed and faeces) are analysed using vertically oscillating grids as a source of turbulence in fluid tanks. An oscillating grid system consists of a container in which a grid is stirred vertically generating a well-known turbulent field that is function of amplitude and frequency of oscillation, distance between grid and measurement point, and mesh spacing of the grid. The grid used in this study had a mesh spacing of 1.2 cm, and was calibrated using different amplitudes (1, 1.5 and 2 cm), frequencies (from 1 to 6 Hz) and distances (2.4, 2.7 and 3 cm). After calibration, the turbulence needed to resuspend biosolids and to maintain them in the water column following different times of consolidation, and with biosolids of different origin, was analysed. It was observed that the turbulence needed to resuspend aquaculture biosolids increased with the time of consolidation. When the turbulence was decreased after a resuspension process, the next sedimentation of biosolids showed a hysteretic behaviour: turbulence needed to resuspend a fixed percent of biosolids from the tank bottom is substantially higher than that needed to maintain the same percentage suspended in the water column. Differences in resuspension behaviour of biosolids originated in different tanks were also observed. The method provides useful information that can be compared with turbulence generated by fish swimming activity, in order to determine the culture conditions, which can promote self-cleaning conditions in a particular tank. Description: Menció d'Honor 2010 que atorga l'Aquacultural Engineering Society 2013-05-06T11:20:17Z http://hdl.handle.net/2117/17395 Title: Flow pattern in aquaculture circular tanks: Influence of flow rate, water depth, and water inlet & outlet features Authors: Oca Baradad, Joan; Masaló Llorà, Ingrid 2013-01-17T11:45:42Z http://hdl.handle.net/2117/14087 Title: Diseño de tanques en acuicultura intensiva Authors: Oca Baradad, Joan; Masaló Llorà, Ingrid; Gutiérrez, Carmen 2011-11-27T18:28:58Z http://hdl.handle.net/2117/9826 Title: Measurement of sole activity by digital image analysis Authors: Duarte Ortega, Sonia; Reig Puig, Lourdes; Oca Baradad, Joan Abstract: Evaluating flatfish activity can be a useful tool for studying fish behavior and welfare. The aim of this workwas to obtain a quantitative index for measuring flatfish activity using image analysis. Accordingly, motor activity of a sole population was recorded by digital video for three nights, bearing in mind the nocturnal lifestyle of the species. Subsequent image analysis was done by image subtraction of consecutive frames. The result was a ‘‘difference frame’’ showing the changes in the image area due to fish movement. Using these data, an image processing activity index (IPAI) was determined by measuring the percentage of area altered due to fish movement and by taking this percentage as an indicator of fish activity. Typical sole behavioral acts (take-off and surface swimming) were recorded by direct observation during the same intervals in order to calibrate the IPAI. A direct observation activity index (DOAI) was determined by weighting each kind of attitude according to its average duration. Results obtained from image analysis (IPAI) were compared with results obtained by direct observation (DOAI). A linear relationship between the two indexes was found with a correlation coefficient of r2 = 0.80 for 92% of coverage area tank and r2 = 0.90 for 210% of coverage area tank. Thus, this digital video-based index can be a highly reliable and accuratemethod for objectivelymeasuring activity levels in sole with a low consumption of labor and time. Nevertheless, the application to farm conditions would need further research and an accurate calibration for other species. 2010-10-19T14:49:15Z http://hdl.handle.net/2117/9090 Title: Stocking density and sex influence individual growth of Senegalese sole (Solea senegalensis) Authors: Sánchez Fernández, Pablo; Ambrosio Jiménez, Pedro Pablo; Flos Bassols, Rosa 2010-09-25T19:44:56Z http://hdl.handle.net/2117/1451 Title: Study of fish swimming activity using Acoustical Doppler Velocimetry (ADV) techniques Authors: Masaló Llorà, Ingrid; Reig Puig, Lourdes; Oca Baradad, Joan 2007-12-28T09:52:39Z http://hdl.handle.net/2117/1428 Title: Stocking density and its influence on shape of Senegalese sole adults Authors: Ambrosio Jiménez, Pedro Pablo; Costa, Corrado; Sánchez Fernández, Pablo; Flos Bassols, Rosa 2007-12-17T15:56:07Z http://hdl.handle.net/2117/731 Title: Comparative analysis of flow patterns in aquaculture rectangular tanks with different water inlet characteristics Authors: Oca Baradad, Joan; Masaló Llorà, Ingrid; Reig Puig, Lourdes 2007-03-28T08:28:38Z http://hdl.handle.net/2117/730 Title: Design criteria for rotating flow cells in rectangular aquaculture tanks Authors: Oca Baradad, Joan; Masaló Llorà, Ingrid 2007-03-28T08:28:20Z