Browsing by Author "Vidal, Mariano"

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Analysis of fluid velocity inside an agricultural sprayer using generalized linear mixed models
(2020) Boné, Antonio; Torres Inga, Carlos Santiago; Guevara Viera, Raúl Victorino; Guevara Viera, Guillermo Emilio; Aguirre De juana, Angel Javier; García Ramos, Francisco Javier; Vidal, Mariano
The fluid velocity inside the tank of agricultural sprayers is an indicator of the quality of the mixture. This study aims to formulate the best generalized linear mixed model to infer the fluid velocity inside a tank under specific operational parameters of the agitation system, such as liquid level, circuit pressures, and number of active nozzles. A complex model was developed that included operational parameters as fixed eects (FE) and the section of the tank as the random eect. The goodness of fit of the model was evaluated by considering the lowest values of Akaike's information criteria and Bayesian information criterion, and by estimating the residual variance. The gamma distribution and log-link function enhanced the goodness of fit of the best model. The Toeplitz structure was chosen as the structure of the covariance matrix. SPSS and SAS software were used to compute the model. The analysis showed that the greatest influence on the fluid velocity was exerted by the liquid level in the tank, followed by the circuit pressure and, finally, the number of active nozzles. The development presented here could serve as a guide for formulating models to evaluate the eciency of the agitation system of agricultural sprayers.
Applicability of ammonia sensors for controlling environmental parameters in accommodations for lamb fattening
(2018) García Ramos, Francisco Javier; Aguirre De Juana, Angel Javier; Barreiro Elorza, Pilar; Horcas, Esperanza; Boné, Antonio; Vidal, Mariano
Electrochemical ammonia sensors were used to analyse the existing relationship between the ammonia concentration and ambient levels of both temperature and relative humidity in commercial lamb fattening housing equipped with mechanical ventilation and straw-bedded pens. In the first stage of the experiment, sensors were placed over straw beds covered in lamb urine and analysed under laboratory conditions in order to determine ammonia emission evolution over time; three control temperatures (25, 35, and 50°C) were used. A HOBO H8 temperature and relative humidity logger and a Dräger NH3LC-6809680 electrochemical ammonia sensor placed in a Dräger Polytron 7000 gas detector were utilized as sensors. A positive correlation was established between both ammonia emission time and emitted amount with temperature. Additionally, tests were performed in a commercial lamb housing to determine ammonia concentration variation with respect to height from the ground; three ammonia sensors placed at 50, 90, and 135 cm above the ground were used simultaneously. The ammonia concentration significantly decreased as height increased. A 90 cm height was selected, and three ammonia probes were placed in three different pens inside the livestock housing, along with temperature and relative humidity sensors; four different housing ventilation rates were then tested under real conditions over a time period of 4 months. An adjustment polynomial equation between the housing ambient temperature and the ammonia concentration was obtained with R2 = 0.632. In conclusion, a relationship can be established between temperature and ammonia concentration in commercial lamb housing under certain handling conditions, which in turn allows for estimating the ammonia concentration adequately based on the ambient internal temperature. © 2018 F. Javier García-Ramos et al.