Tight-Binding Molecular Dynamics Simulations on Point Defects Diffusion and Interactions in Crystalline Silicon

Tight-binding molecular dynamics (TBMD) simulations are performed (i) to evaluate the formation and binding energies of point defects and defect clusters, (ii) to compute the diffusivity of self-interstitial and vacancy in crystalline silicon, and (iii) to characterize the diffusion path and mechanism at the atomistic level. In addition, the interaction between individual defects and their clustering is investigated

Co-hydrothermal carbonization of swine manure and lignocellulosic waste: a new strategy for the integral valorization of biomass wastes

Co-hydrothermal carbonization (co-HTC) is a promising strategy to improve hydrothermal carbonization (HTC) of low-quality wastes. HTC of swine manure (SM), with high N (2.9 wt%), S (0.7 wt%) and ash (22.6 wt%) contents, as well as low C (35.6 wt%) and higher heating value (HHV; 14.3 MJ kg−1), resulted in a hydrochar with unsuitable characteristics as a solid fuel. Co-HTC of SM and garden and park waste (GPW) improved hydrochar properties (C content (43 – 48 wt%) and HHV (18 – 20 MJ kg−1), and decreased N (∼2 wt%), S (50 wt%) during co-HTC resulted in a hydrochar similar to that obtained from GPW. The co-HTC increased nutrient migration to the process water, which allowed the precipitation of salt with high P (7.8 wt%) and negligible heavy metal content. Anaerobic digestion of co-HTC process water allowed high organic matter removal (up to 65%), and methane production (315 – 325 mL CH4 g-1CODadded). Gross energy recovery by HTC and anaerobic digestion was 5 – 6-fold higher than anaerobic treatment of feedstocks. Therefore, co-HTC of SM and GPW with a ratio > 50% GPW proved to be a suitable approach to valorize and manage SM and obtain value-added products (hydrochar, mineral fertilizer and methane)Authors greatly appreciate funding from Spain’s MICINN (PID2019- 108445RB-I00), MINECO (PDC2021-120755-I00 and TED2021- 130287B-I00), Madrid Regional Government (Project S2018/EMT4344), and Grupo Kerbest Company. R.P. Ipiales acknowledges the financial support from the Community of Madrid (IND2019/ AMB17092) and Arquimea Agrotech Compan

Local knowledge of native potato (Solanum spp) for long-term monitoring on three Andean Communities of Apurimac, Peru.

Multiple drivers related to changes in climate and socio-cultural structure in the Peruvian Highland are of increasing importance for the loss of the biological diversity of potato landraces and related collective knowledge in their center of diversity. For example in the district of Haquira, which is located in the province of Cotabambas, Apurimac, many young farmers abandon agriculture to work in the mines or migrate to search for more income attractive options in larger towns. The precise impact of these tendencies on agrobiodiversity has not been assessed and it remains difficult to establish timelines that reflect changes as no reference data exist that is useful for comparison. A cost efficient and easy applicable method to assess local crop diversity based on traditional names and establish a baseline for red-listing of landraces is the five cell analysis (FCA). In a case study, three communities in Haquira – Pauchi, Queuñapampa and Huancacalla Chico have been surveyed to determine the actual state of potato landrace, collective knowledge, potential threats of agrobiodiversity and to establish a long term monitoring system. It was registered by focus groups familiar (n=61). The results provide us information systematization of landraces of potatoes to prepare a master list that can be contrasted with genetic information. Based on farmer's perception in all the communities it was identified 42 landraces with 71 synonyms; 13 threatened landraces, 8 conservation dependant landraces and 3 no risk landraces. The methodologies used to contributing to data base for monitoring of landraces of potatoes should be applicable to other landscapes on similar conditions

Fate of nutrients during hydrothermal treatment of food waste

Hydrothermal carbonization was evaluated as a food waste valorization strategy to obtain hydrochar and recover nutrients. In the hydrothermal treatment, the temperature (170–230 °C), reaction time (5–60 min), and addition of HCl (0.1–0.5 M) during the reaction were analyzed. Compared to the feedstock, hydrochar showed an increase in fixed carbon (greater than 45%) and a decrease in ash content (<7%), along with a higher heating value (18.6–26.2 MJ/kg), which would allow for its application as a biofuel for industry according to ISO/TS 17225–8. The hydrochar obtained using plain carbonization showed 75% P and 40% N of the feedstock content, whereas the HCl-mediated treatment (0.5 M) solubilized most of the P, K, and N in the process water (98% P as PO4-P, 98% K, and the total N content as NH4-N (16%) and organic-N) operating at 170 °C for 60 min.The authors greatly appreciate funding from Spanish MICINN (Project PID2019-108445RB-I00) and Madrid Regional Government (Project S2018/EMT-4344). A. Sarrion wishes to thank the Spanish MICINN and ESF for a research grant (BES-2017-081515). The authors thank Silvia Rodríguez for her valuable hel

Energy recovery from garden and park waste by hydrothermal carbonisation and anaerobic digestion

Hydrothermal carbonisation (HTC) can transform wet lignocellulosic biomass, which is not considered an effective biofuel for energy production at the industrial level, into a carbonaceous product called hydrochar (HC) that is suitable for combustion and a process water (PW). PW is an interesting by-product that can be valorised for biogas production via anaerobic digestion (AD). This study presents a new approach for the valorisation of garden and park wastes (GPW) by integrating HTC to generate HC for energy production, while PW is subjected to AD for biogas production. The hydrothermal treatment was performed at 180, 210, and 230 °C, yielding HC with improved physicochemical properties, such as an elevated higher heating value (21–25 MJ kg−1); low ash (<5 wt.%), nitrogen (1.3 wt.%), and sulphur (0.2 wt.%) contents; better fuel ratio (0.4–0.6); and a broad comprehensive combustibility index (8.0×10−7 to 9.6×10−7 min−2 °C−3). AD of the generated PW was conducted under mesophilic conditions (35 °C), resulting in a methane production in the range of 253–326 mL g−1 CODadded and COD removal of up to 65%. The combination of HTC and AD allowed the recovery of 91% and 94% of the energy content feedstock, as calculated from the combustion of HC and methane, respectivelyThe authors gratefully acknowledge funding from Spain’s MINECO (PID2019-108445RB-I00; PDC2021-120755-I00) and the Comunidad de Madrid (Project S2018/EMT-4344). R. P. Ipiales acknowledges financial support from the Comunidad de Madrid (IND2019/AMB-17092) and the Arquimea-Agrotech Compan