Andmebaasi logo

Sirvi Autor "Cadavid, V.G." järgi

Nüüd näidatakse 1 - 3 3
  • Pisipilt
    Kirje
    Decision three to predict respiratory rate of piglets submitted to cold conditions
    (Estonian University of Life Sciences, 2021) Ferraz, P.F.P.; Cadavid, V.G.; Ferraz, G.A.S.; Saraz, J.A.O.; Rossi, G.; Barbari, M.
    Pigs subjected to thermal conditions outside their comfort zones may show altered physiological and behavioural responses, which may consequently cause productive losses. For these reasons, the aim of this paper is to develop a decision tree for the prediction of respiratory rate (RR, mov min-1 ) of piglets exposed to different thermal situations. The experiment was carried out in an experimental pig farm of the Universidad Nacional de Colombia Campus Medellin, located at the San Pablo Agraria Experimental Station located in the eastern sector of the department of Antioquia, during August 2019. A database containing the raw data for dry bulb temperature - tdb (°C), and relative humidity - RH (%) as input variables, and RR (mov min-1 ) of six piglets were assessed every two hours as output variable for piglets was generated. The experimental database was composed of 78 observed data. The decision trees were developed to conditions of tdb between 19.2 to 29.5 °C and RH between 50.2 to 88.4%. In the experimental period, RR of piglets submitted to tdb higher than 27.1 °C the RR was around 60 mov min-1 , tdb smaller than 27.1 °C the RR varied from 36 to 46 mov min-1 . These low values of physiological responses may indicate that the piglets are not in a comfortable situation, so their development, welfare and production can be affected. The decision tree developed can be useful to provide a quick understanding of the piglet’s welfare condition based on the environmental variables and physiological responses.
  • Pisipilt
    Kirje
    Spatial variability of methane and carbon dioxide gases in a Compost-Bedded Pack Barn system
    (Estonian University of Life Sciences, 2024) Ferreira, J.C.; Ferraz, P.F.P.; Ferraz, G.A.S.; Oliveira, F.M.; Cadavid, V.G.; Rossi, G.; Becciolini, V.
    The dairy sector significantly contributes to global food production, however, it is closely associated with environmental concerns, specifically the emission of greenhouse gases such as methane (CH4) and carbon dioxide (CO2). The research problem focuses on the environmental impact of livestock farming, particularly in relation to the emission of greenhouse gases (GHG) such as methane (CH4) and carbon dioxide (CO2). Therefore, the objective of this paper was to assess the spatial variability of CH4 and CO2, as well as the thermal environment through the Temperature and Humidity Index (THI) and of air velocity (V, m s-1) in a Compost Bedded Pack (CBP). The experiment was carried out in October 2023, in a commercial dairy cattle facility measuring 54×22×4.5 m (length×width×height) that housed 80 lactating cows. Measurements were collected at 75 points, 0.25 m above the bedding, for one minute in each point. To characterize the distribution of gases and the thermal environment, the data were underwent geostatistical techniques and kriging maps. THI values ranged from 72.4 to 78.4, categorizing the animals into two environments within the facility, comfort and alert to thermal conditions. The maximum recorded for CO2 was 713.60 ppm in the region with a low ventilation incidence. CH4 reached a ranging from 103.38 to 196.73 ppm in areas with low ventilation and higher temperatures. The use of geostatistics enabled the characterization of spatial variability of greenhouse gases CH4 and CO2, as well as THI and V. Analyzing these variables is crucial for implementing mitigation actions and developing an increasingly sustainable production system.
  • Pisipilt
    Kirje
    Thermal analysis of cement panels with lignocellulosic materials for building
    (2020) Ferraz, P.F.P.; Mendes, R.F.; Ferraz, G.A.S.; Carvalho, V.R.; Avelino, M.R.C.; Narciso, C.R.P.; Eugênio, T.M.C.; Cadavid, V.G.; Bambi, G.
    The use of lignocellulosic material residue in cement composites can be considered as a good option because they allow good thermal behaviour. This paper aimed to compare three kinds of cement panels reinforced with different lignocellulosic materials (Coffee husk, Coconut shell, and Banana pseudostem) based on their thermal properties. To produce each panel, the methodology suggested by Souza (1994) was used. Six replicates of each lignocellulosic panel with dimensions of 7.0×7.5 were evaluated. The thermal analysis was performed in a chamber composed of MDP (medium density particleboard). The chamber contained the heat source (incandescent lamp) connected to a thermostat that maintained the temperature at 48.0 °C. The porosity and thickness of the panels and the thermal behaviour of each sample panel (thermal conductivity, resistivity, resistance, and transmittance) and the difference in temperature of both sides of the panel were evaluated. The temperature difference to stabilization was obtained after a sampling time of 200 minutes, with 1,000 readings of 12 s each. Although all the panels were submitted under the same temperature, the inner and external superficial temperatures of the coffee husk panels reached smaller values. Besides, coconut and banana pseudostem panels presented the best results of thermal transmittance and thermal resistance. Thus, coconut shell panels present the best thermal performance, which means that this panel might be an attractive alternative building material, in terms of heat insulation for indoor applications.