Methane production from food waste using a feedback control strategy in a sequencing batch reactor

The performance of a feedback control strategy in the operation of a sequencing batch reactor was evaluated. This strategy uses the online biogas flow measurements to define the duration of the reaction phase of each operating cycle, thereby increasing the energy production of the system and maximizing the methane production rate. The reaction phase is ended when the biogas flow rate reaches a sustained value significantly lower value than the maximum flow rate achieved, as a consequence of the depletion of the CODsoluble. The implementation of the depletion-time control was successful and reached a maximum methane production rate of 1.22 LCH4/d, showing an average productivity of 0.73 ± 0.3 LCH4/d. The reaction phase varied from 1.2 to 6 days with hydraulic retention times from 6 to 30 days. The use of this feedback control strategy increased the methane production and the energy production in 80% of the evaluated cycles (from 10.4 to 43.8%) compared to the operation of conventional anaerobic digestion without a control strategy. Furthermore, the strategy is easy to implement since it does not require complex calculations and uses a readily available biogas flow rate sensor.

Metal-Alkali Catalytic Valorization of Lignocellulose Towards Aromatics and Small Molecular Alcohols and Acids in a Holistic Approach

In this work, we developed an approach of one-pot completely catalytic conversion of woody biomass into two value product streams: lignin-derived aromatics (68.54% monomer and 29.65% oligomer yields of lignin) and (semi-)cellulose-derived small molecular alcohols (about 59.60% of biomass mass). These could be afforded by conducting lignocellulose depolymerization over metal-alkaline catalysts in a mixture n-butanol/H2O solvent system at 250 °C and 30 bar H2. In the valorization process, the homogenous mixture of n-butanol-H2O solvents extract and depolymerize both lignin and hemicellulose, while the catalysts and H2 are essential to cleave the inter-/intramolecular linkages of lignocellulose into target products. After the reaction, phase separation of n-butanol and H2O takes place when systematic temperature at room temperature, providing a mild and effective strategy to isolate lignin-derived aromatics (n-butanol phase) from small molecular alcohols/acids (aqueous phase). Ru/C and alkali catalysts are collected by filtration from n-butanol phase and H2O phase, respectively. Meanwhile, the effect of metal-alkali coupled catalysts enables facilitating the cleavage of β-O-4 linkage of lignin and increasing the attainability of (semi-)cellulose-derived oligomers and the small molecular alcohols. This catalytic system provides a versatile valorization approach for biomass catalytic to bio-based chemicals.

Experiencing a 20th-century visual artwork – Andy Warhol

This paper presents the results of a research on students' reactions to 20th-century visual artworks. The research involved 300 students attending lower grades of primary school (Grade 1-4) from Split-Dalmatia County. The aim of the research was to examine the reactions of students to the works of the famous Pop Art artist Andy Warhol, using the method of aesthetic transfer. The task of the students was to describe their impression of the observed paintings of Marilyn Monroe and Coca-Cola. Based on the results obtained, it can be concluded that Grade 1 1-4 students react positively to the mentioned artworks. Most of the children accepted the works of the famous artist. Students were expected to react differently to the observed artworks with respect to gender and age, while the research showed that a statistically significant difference existed in only one segment of the research. Additionally, the emotional engagement aroused in students by the observed works was studied. The results in the reception phase show students mostly react emotionally to the observed artworks. Furthermore, the artworks in the reaction phase showed interesting creative variations on the artwork of the famous artist, which means that they inspired the students to a creative aesthetic response. Apart from getting acquainted with 20th-century artworks, we can see from these examples that they can also be a good stimulus for articulating students' own artistic expression.Keywords: students, visual artworks, attitudes, motif, Andy Warhol