ZnO-ZrO2 nanocomposites using zinc (II) acetylacetonate and different ZnO contents (13, 25, 50, and 75% mol) were synthesized through sol-gel method. The synthesis process was strongly related to nanocomposite properties especially on their structural composition. The obtained ZnO-ZrO2 nanomaterials presented tetragonal crystalline structure for zirconia whereas hexagonal one was formed in ZnO. Raman spectroscopy and XRD patterns confirmed the formation of tetragonal zirconia whereas inhibition of monoclinic structure was observed. Addition of ZnO affected the pore size distribution of the composite, and the measured specific surface areas were from 10 m2/g (for pure ZnO) to 46 m2/g (pristine ZrO2). Eg values of ZrO2 were modified by ZnO addition, since calculated values using Kubelka-Munk’s function varied from 4.73 to 3.76 eV. The morphology and size of the nanomaterials investigated by electron microscopy showed formation of nanorods for ZnO with sizes ranging from 50 nm to 300 nm while zirconia was formed by smaller particles (less than 50 nm). The main advantage of using the nanocomposite for photocatalytic degradation of phenol was the mineralization degree, since 75ZnO-ZrO2 nanocomposite surpassed mineralization reached by pure ZnO and also inhibited formation of undesirable intermediates.

RESUMENLos rumiantes contribuyen significativamente a las emisiones de metano en las regiones tropicales. Sin embargo, hay pocas instalaciones disponibles para la medición in vivo de estas emisiones. Por lo anterior, el objetivo del presente trabajo fue describir el diseño, construcción y operación de cámaras de respiración para la medición in vivo de la producción de metano de bovinos en México. En la construcción se utilizaron materiales disponibles localmente. Las paredes, el techo y las puertas se construyeron de paneles térmicos con dos ventanas de acrílico, en ambos lados, en la parte delantera. Las cámaras tienen un volumen de aire de 9.97 m 3 . El aire de la cámara se extrae con una bomba de flujo de masas a una velocidad de 500 L/min. El metano mezclado en las muestras de aire se cuantificó con un analizador de infrarrojo. Las cámaras funcionan bajo presión negativa de -500 Pa. La temperatura y humedad relativa se mantiene a 23 °C y 55 %, respectivamente. El funcionamiento de las cámaras se evaluó utilizando ganado Bos indicus, de la raza Nelore, alimentado con pasto de Taiwán (Pennisetum purpureum) y un concentrado con 18 % de proteína cruda; y se realizaron mediciones con las cámaras durante 23 h. La producción de metano fue de 173.2 L/día, mientras que el factor de emisión fue de 17.48 L de metano/kg de materia seca consumida. Se concluye que las cámaras de respiración pueden medir con precisión la producción de metano en ganado Nelore consumiendo raciones tropicales. PALABRAS CLAVE: Metano, Rumiantes, Trópicos, Gases de efecto invernadero, Cámaras de respiración.

In this study, the effect of chia mucilage (CM) and protein concentrate (CPC) contents on the physicochemical, thermal, mechanical, and optical characteristics of developed films was evaluated. Films were prepared dissolving CM:CPC mixtures (1% w/v) in seven ratios (0:1, 1:4, 1:2, 1:1, 2:1, 4:1, 1:0). Microstructure of treatments with higher CM revealed the formation of polysaccharide granules. A semicrystalline behavior was manifested in 1:0, which decreased as CPC content in the formulations increased. Contact angle values obtained for 1:1 and 2:1 were the highest (61.24°and 62.44°), evidencing less affinity to water than other films. TGA analysis suggest that films showed thermal stability at less than 225°C. Melting temperatures above 85°C were found for all films in the evaluated range (50°C to 200°C) of DSC analysis. Higher CM concentrations in films increased the force required to break them (13.5 MPa) and their elongation capacity (5.20%). As the CM ratio in formulations was increased, the color difference was lower ( E = 27.45), water vapor permeability was higher (10.9 × 10 −11 g/m·s·Pa), but transparency was statistically the same for all treatments (6.62 to 7.26). After analyzing all films properties, 2:1 formulation corresponding to 25:75% w/v mixtures of CM:CPC would be the best option for use in food packaging.

Chia oil contains a high content of linoleic and linolenic acid, which are essential for human metabolism. Chia nanoemulsion is a technique that can aid in preserving the components of this oil. This study aimed to develop and characterize chia oil nanoemulsions using chia mucilage as wall material. The nanoemulsions were developed varying the use of ethanol to check for any influence in the stability and the content of chia oil (0.043, 0.100, and 0.233 ml) and chia mucilage (0.125, 0.250, and 0.375 g) through high‐speed stirrer. The smallest particle size, polydispersity index, zeta potential suitable, high encapsulation efficiency, and stability of agitation were the parameters for choosing treatments with (T4E) and without (T4) ethanol with 0.375 g of chia mucilage and 0.233 ml of chia oil. The chosen nanoemulsions were characterized, being verified that the encapsulation was efficient. Also, during the stability evaluation, it was seen that the T4 presented smaller particle size and lower polydispersity index. The rheological parameters indicated that all nanoemulsions presented shear‐thinning and semi‐liquid viscoelastic behaviors. The nanoemulsions produced can be used in foods, because they facilitate the incorporation and preservation of the chia oil in food formulations and making them more nutritious. Novelty impact statement The development of chia oil nanoemulsion was performed using different concentrations of chia mucilage as an encapsulating material and varying the use of ethanol as an aid to the formation of drops. Physicochemical, morphological, stability, and technological characteristics were evaluated. Chia oil nanoemulsions with the addition or not of ethanol can be applied to food preserving chia oil from oxidation, in addition to facilitating the incorporation of oil into the food.

This research presents a qualitative description of the degradation phenomena that occurred in external walls of the San Carlos Bastion, San Francisco de Campeche, Campeche City, (Mexico), a military structure built with calcareous materials between 16 th and 17 th centuries. Several weathe-investigación / research