• Energy Research

The usefulness of a nutrient-enriched zeolite (NEZ) obtained from simultaneous ammonium (NH4+) and phosphate (PO43-) recovery from urban wastewaters was evaluated as soil amendment through the early growth of sunflower (Helianthus annuus). The NEZ systems were applied to sandy (acid) and clayey (basic) soils from Mediterranean agricultural areas (Spain). Some plant growth indicators were measured: evapotranspiration, plant moisture content, plant biomass, root/shoot ratio, nitrogen and phosphorous uptake and the C/N ratio. The experimental data exhibited differences in the growth indicators for un-amended and amended soils. The addition of the NEZ system increase the plant water content of sunflowers grown on clay soils. The plant biomass of sunflower was improved by the incorporation of NEZ system in all treatments for the two soils studied. A reduction of the root/shoot ratio for the treatments of clay soil by application of NEZ systems were observed. The content of ammonium and phosphorous in tissues increased considerably with the addition of amendment material. Besides, the ammonium, nitrate and inorganic phosphorous in the post-test soils revealed that nutrients were still available for a second growth cycle. As demonstrated in previous work, the NEZ system releases nutrients continuously controlled by soil pH and mineral composition as well as the irrigation conditions provided. Therefore, this approach of amendment materials for soil seems to be a promising alternative for agricultural practice, where the dose selection must be balanced according to the plant's nutrient needs and soil properties by adjusting the growth conditions.

In higher education, the learning of Unit Operations in Chemical Engineering and the development of practical activities became a real challenge. Therefore, the use of emerging technologies became necessary to develop practical laboratory activities of the Unit Operations due to the inaccessibility to the equipment infrastructure. In this study, Project-Based Learning methodology was assisted with the Augmented Reality (AR) technology for the development of subjects. The development of a real educational experiment for the application of a basic topic of the course as a project for each subject was proposed. The results were presented using the Zappar application, and a unique rubric was used for the evaluation of project. The evaluation of students’ motivation for learning was measured using Keller’s Attention, Relevance, Confidence and Satisfaction (ARCS) model of motivation by Instructional Materials Motivation Survey (IMMS). The attention, confidence and satisfaction demonstrate an acceptable reliability in comparison to relevance, which was considered as moderate reliability. Above 96% of students considered that the activities, materials, and organization of information used for the AR project caught their attention and encouraged their interest towards the fundamentals applied in the project. Around 80% of students expressed concern about the ease of AR technology use, and understood the learning aim of the project. Above 85% of students recognized the relevance of activities and their usefulness, and considered AR as a meaningful educational tool. 90% of students considered that AR technology helped them to develop the subject competencies. Cronbach’s Alpha was used to indicate an acceptable reliability of IMMS instrument. Regarding IMMS, values were superior to 0.7, which could be considered acceptable. For the individual ARCS dimensions, values of Cronbach’s alpha reached values of 0.94.