Artículos científicos
https://hdl.handle.net/11323/18
Artículos de investigación publicados por miembros de la comunidad universitaria.2024-03-28T14:13:01ZAntimicrobial bilayer film based on chitosan/electrospun zein fiber loaded with jaboticaba peel extract for food packaging applications
https://hdl.handle.net/11323/10916
Antimicrobial bilayer film based on chitosan/electrospun zein fiber loaded with jaboticaba peel extract for food packaging applications
Bataglin Avila, Luisa; Pinto, Diana; Silva Oliveira, Luis Felipe; Silva de Farias, Bruna; Costa Moraes, Caroline; ROSA, GABRIELA SILVEIRA DA; Dotto, Guilherme Luiz
This work focused on developing an active bilayer film based on natural extract. Thus, the jaboticaba peel extract (JPE) was produced and characterized and showed promising application as a natural additive in biopolymeric materials. The zein fiber and bilayer films were produced using a chitosan film (casting) and zein fiber (electrospinning), with and without JPE. All samples were evaluated according to thickness, solubility in water, water vapor permeability, and main diameter, and for these, zein fiber, chitosan/zein fiber, and chitosan/zein fiber + 3% JPE showed values of 0.19, 0.51, and 0.50 mm, 36.50, 12.96, and 27.38%, 4.48 × 10−9, 1.6 × 10−10, and 1.58 × 10−10 (g m−1 Pa−1 s−1), and 6.094, 4.685, and 3.620 μm, respectively. These results showed that the addition of a second layer improved the barrier properties of the material when compared to the monolayer zein fiber. The thermal stability analysis proved that the addition of JPE also improved this parameter and the interactions between the components of the zein fiber and bilayer films; additionally, the effective presence of JPE was shown through FTIR spectra. In the end, the active potential of the material was confirmed by antimicrobial analysis since the bilayer film with JPE showed inhibition halos against E. coli and S. aureus.
2022-12-13T00:00:00ZAn implicit formulation for calculating final conditions in drainage maneuvers in pressurized water installations
https://hdl.handle.net/11323/10915
An implicit formulation for calculating final conditions in drainage maneuvers in pressurized water installations
Coronado-Hernández, Oscar E.; BONILLA CORREA, Dalia Melissa; Lovo, Aldo; Fuertes-Miquel, Vicente S.; Gustavo, Gatica; Linfati, Rodrigo; Coronado-Hernandez, Jairo R.
Emptying processes are typical maneuvers that should be performed by water distribution companies for operation purposes. These processes involve a complex numerical analysis, since a set of algebraic and ordinary differential equations needs to be solved for the intricacy of hydraulic and thermodynamic formulations for two analyzed phases (liquid and gas). This research provides an implicit equation to compute exactly the final conditions in water emptying operations in single pipelines without an air valve (or admitted air). The implicit expression was developed by considering that for all final conditions, the water velocity is null, and thus, the water column length and air pocket pressure can be computed. The friction factor, internal pipe diameter, and opening maneuvers of drain valves do not disturb the final conditions in draining processes. The developed implicit formulation was validated using experimental measurements in a pipeline with a total length of 4.36 m. The equation is of utmost importance, since it can be utilized for engineers to easily plan for future conditions in water distribution networks.
2023-10-23T00:00:00ZActive films based on starch and wheat gluten (Triticum Vulgare) for shelf-life extension of carrots
https://hdl.handle.net/11323/10914
Active films based on starch and wheat gluten (Triticum Vulgare) for shelf-life extension of carrots
Rivera Leiva, Andrés Felipe; Hernández-Fernández, Joaquín; Ortega Toro, Rodrigo
The use of biodegradable biopolymers with the incorporation of active ingredients has been considered as an alternative to extend the useful life of food. Therefore, the objective of this research was to develop active films based on starch and wheat gluten, containing cinnamon and turmeric essential oils by using the solvent casting method. Different film formulations were made from wheat starch, gluten, glycerol, and essential oils of cinnamon and turmeric. The films were characterized according to their morphology, optical, thermal, antioxidant, and barrier properties. Subsequently, the active properties on baby carrots regarding weight loss, appearance, and fungal growth were evaluated. The results indicated that the starch-based films showed a slight decrease in moisture content with the addition of essential oils (up to 13.29%), but at the same time showed a significant reduction in water solubility (up to 28.4%). Gluten-based films did not present significant differences in these parameters, although the solubility in water tended to increase (up to 13.15%) with the addition of essential oils. In general, the films presented good thermal stability and antioxidant capacity, and in the carrot coating test, a decrease in weight loss of up to 44.44% and 43.33% was observed for the coatings based on starch and gluten with the addition of turmeric essential oil, respectively. Finally, films developed with cinnamon and turmeric essential oils are potential candidates for the design of biodegradable active packaging.
2022-11-23T00:00:00ZActive disturbance rejection control for robot manipulator
https://hdl.handle.net/11323/10913
Active disturbance rejection control for robot manipulator
Martínez Ochoa, Carlos E. ; Benítez González, Ivón Oristela; Cepero Díaz, Ariel Omar; Nuñez-Alvarez, José R.; Miguélez-Machado, Carlos G.; Llosas Albuerne, Yolanda
Active Disturbance Rejection Control (ADRC) is a control methodology used in chemical processes, aircraft, motors, and other systems. This paper compares the results of an ADRC controller to a Proportional Integral Derivative controller (PID), applied to two degrees of freedom robots. A Linear Extended State Observer (LESO) is used to reconstruct the state variables and unknown parameters needed to control the position of each link. The ADRC can achieve the tracking position and estimate the velocity of each link. The results of the simulation program are shown.
2022-01-01T00:00:00Z