Investigations into Physical and Fuel Characteristics of Briquettes Produced from Cassava and Yam Peels

Globally, 140 billion metric tons of biomass is generated every year from agriculture. This volume of biomass can be converted to an enormous amount of energy and raw materials. These residues are usually dumped and flared on the farms, where they constitute health risk to both human and ecology. Densification of these residues would improve their bulk handling, transportation and storage properties. Therefore, this work investigated densification characteristics of cassava and yam peels using an experimental briquetting machine. The ASAE standard methods were used to determine the moisture contents (dry basis) and densities of the milled residues and briquettes, while ASTM standard methods were used to determine the proximate and ultimate analyses of the residues. The initial, maximum and relaxed densities were also determined using ASAE standard methods. Also evaluated were compaction, density and relaxation ratios of the briquettes. The mechanical properties were determined using universal testing machine, while the heating value was determined using Ballistic Bomb calorimeter. The mean moisture contents of cassava and yam peels residues were 10.19% and 9.27% respectively, while those of relaxed briquettes were 8.76% and 7.95% respectively.  The initial, maximum and relaxed densities were 251.50 kg/m3; 741.13 kg/m3 and 386.4 kg/m3 respectively for briquettes produced from cassava peel, while the corresponding values for briquettes produced from yam peel were 283.40 kg/m3; 911.45 kg/m3 and 512.54 kg/m3 respectively. The compaction ratio of 2.94 and 3.21 were obtained for briquettes produced from cassava and yam peels respectively. The compressive strength of briquette from cassava peel was 1.53kN/m2 (SD 0.05), while that of yam peel was 1.76kN/m2 (SD 0.04). The higher heating value of briquettes from cassava peel was found to be 12,765kJ/kg (SD 30), while the corresponding value for yam peel was 17,348kJ/kg (SD 20). The results of this work indicate that briquettes produced from the two biomass residues would make good biomass fuels. However, findings show that yam peel briquette has more positive attributes of biomass fuel than its cassava peel counterpart. It has a moderate moisture content of 10.95 %, higher density of 911.45 kg/m3 and lower relaxation ratio of 1.78. Other positive attributes of yam peel briquette over cassava peel are long after glow time of 375 secs and slow propagation rate of 0.16 cm/s. It also has higher heating value of 17,348 kJ/kg and compressive strength of 1.76 kN/m2 compared to cassava peel, which are 12,765 kJ/kg and 1.53 kN/m2 respectively. Keywords: agricultural wastes, briquette, briquetting machine, cassava peel, yam peel

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries