The aim of this study was to determine the main thermal properties of the granular mass of coffee (specific heat, thermal conductivity, and thermal diffusivity) for different degrees of roasting, as well as to model and simulate thermal conductivity at different degrees of roasting. For determination of specific heat, the mixing method was used, and for thermal conductivity, the theoretically infinite cylinder method with a central heating source. Thermal diffusivity was simulated algebraically using the results of the properties cited above and of the apparent specific mass of the product. Thermal conductivity was also simulated and optimized through finite element analysis software. At darker roasting, there was an increase in specific heat and a reduction in thermal conductivity and thermal diffusivity. Comparing thermal conductivity determined in relation to simulated and optimized conductivity, the mean relative error was 1.02%, on average.

This study proposed a classification model for 125 agricultural productive units (APUs) in Tolima, Colombia, to establish whether they are related to the quality of coffee produced. The model considered two aspects related to farmer profile and farm profile. The following proposed categories resulted from the coordinate obtained in relation to the two aspects: Low-Low, High-Low, Low-High, and High-High. The variables for each aspect were prioritized using the analysis hierarchical process (AHP). The coffee’s quality, sensory profile by attribute, and specific descriptors for each category were determined employing the Specialty Coffee Association (SCA) protocol. The sensory attributes were analyzed by way of one-way analysis of variance (ANOVA), and the Bonferroni test was used to compare by category, both with a significance level of α = 0.05. The model grouped the APUs by category and cup quality, with the High-High category achieving the best scores in the sensory analysis. The variables with the greatest relative weight within the AHP model constituted farmer stance regarding the use of good agricultural practices (44.5%) and farmer attitude toward excellence (40.6%) in the farmer’s profile. As part of the farm’s profile, environmental commitment level (38.0%) and international certifications (29.1%) were the greatest relative weights. Coffee in the High-High category was characterized by its notes of cinnamon, cocoa, chocolate, and dried vegetables.

El trabajo consistió en determinar el potencial de reutilización del efluente de la Planta de Tratamiento de Aguas Residuales (PTAR) del municipio Nátaga, departamento Huila, Colombia, con fines de irrigación para un cultivo de cacao (Theobroma cacao L.). Este efluente es vertido a la Quebrada El Pueblo, creando problemas de contaminación y de riesgos de salud pública. Aplicando vigilancia tecnológica, se elaboró el estado del arte y recolección de información, para caracterizar el efluente y evaluar la PTAR; se calculó el balance hídrico del cultivo y los beneficios potenciales de la reutilización en riego de estas aguas residuales. El efluente de la PTAR pertenece a la clase C2S1 (CE = 0,54 dS/m, RAS = 1,5), con peligro de salinización medio y de alcalinización bajo para agua de riego; por su riesgo microbiológico es categoría B (CF = 105 NMP/100mL, HH = 21 HH/L), exigiendo adecuado manejo del riego, que minimice los riesgos de salud pública. La zona de influencia tiene déficit hídrico durante todo el año y el efluente constituye un recurso potencial para el cultivo de cacao, aportando en promedio 223.720 m³/año de agua, macronutrientes N (7.273kg/año), P (839kg/año), K (2.797kg/año) y lodos (958 kg/año de materia seca); con el efluente en verano, se puede regar en promedio 19ha de cacao y, en invierno, 27ha. Se recomienda el riego del cacao con el efluente de la PTAR, pero se debe tener cuidado con los efectos sobre el suelo, la planta y la salud pública.