Sunlight heats the greenhouse air temperature and tomato cracking decreases marketable product up... more Sunlight heats the greenhouse air temperature and tomato cracking decreases marketable product up to 90%. A shade screen reduced incoming radiation during warm and sunny conditions to reduce tomato cracking. A fuzzy controller managed greenhouse irrigation to reduce tomato cracking using as variables solar radiation and substrate temperature. The embedded controller presented 9 rules and three assumptions that made it operate better. Signal peaks were removed and control actions could take place ten minutes after irrigation. Irrigation was increased during the peak hours from 12:00 to 15:00 h when it was required by the fuzzy controller; meanwhile water containing the nutrient solution was removed during very cloudy days with limited photosynthesis. After three continuous cloudy days irrigation should be scheduled to avoid plant nutrient problems. Substrate temperature in volcanic rock can be used as real time irrigation sensor. Tomato cracking decreased to 29% using the fuzzy contr...
Rhizopus stolonifer causes significant postharvest losses and about 80% of the total loss in pre-... more Rhizopus stolonifer causes significant postharvest losses and about 80% of the total loss in pre-packaged and loose tomato fruits were due Alternaria rot and Rhizopus rot. The feasibility of using near infrared spectroscopy (NIR) for Rhizopus stolonifer conidia detection was studied. Visible and near infrared spectra were acquired before and after inoculating 200 tomatoes in the laboratory. The spectral data were studied using discriminant analysis, and Rhizopus stolonifer conidia were detected with an accuracy of 78%. A test set of 200 tomatoes was used for testing the algorithm, measuring the fruits only once. Spore-free and infected tomatoes were classified with an accuracy of 81 and 75%, respectively, and 96% of the infected tomatoes were properly detected by a neural network method.
Sunlight heats the greenhouse air temperature and tomato cracking decreases marketable product up... more Sunlight heats the greenhouse air temperature and tomato cracking decreases marketable product up to 90%. A shade screen reduced incoming radiation during warm and sunny conditions to reduce tomato cracking. A fuzzy controller managed greenhouse irrigation to reduce tomato cracking using as variables solar radiation and substrate temperature. The embedded controller presented 9 rules and three assumptions that made it operate better. Signal peaks were removed and control actions could take place ten minutes after irrigation. Irrigation was increased during the peak hours from 12:00 to 15:00 h when it was required by the fuzzy controller; meanwhile water containing the nutrient solution was removed during very cloudy days with limited photosynthesis. After three continuous cloudy days irrigation should be scheduled to avoid plant nutrient problems. Substrate temperature in volcanic rock can be used as real time irrigation sensor. Tomato cracking decreased to 29% using the fuzzy contr...
Rhizopus stolonifer causes significant postharvest losses and about 80% of the total loss in pre-... more Rhizopus stolonifer causes significant postharvest losses and about 80% of the total loss in pre-packaged and loose tomato fruits were due Alternaria rot and Rhizopus rot. The feasibility of using near infrared spectroscopy (NIR) for Rhizopus stolonifer conidia detection was studied. Visible and near infrared spectra were acquired before and after inoculating 200 tomatoes in the laboratory. The spectral data were studied using discriminant analysis, and Rhizopus stolonifer conidia were detected with an accuracy of 78%. A test set of 200 tomatoes was used for testing the algorithm, measuring the fruits only once. Spore-free and infected tomatoes were classified with an accuracy of 81 and 75%, respectively, and 96% of the infected tomatoes were properly detected by a neural network method.
Uploads
Papers by Federico Hahn