Figure 5
A Venn diagram illustrating keyword co-occurrence clusters. The diagram consists of four overlapping circles, each representing a distinct cluster of related keywords. Cluster 1, highlighted in red, focuses on municipal solid-waste management, including terms like waste management, energy recovery, and life-cycle assessment. Cluster 2, in blue, centers around alternative fuels and combustion, with keywords such as cement industry, coal, and solid recovered fuel. Cluster 3, shown in green, encompasses themes related to the cement industry and waste, including co-processing, performance, and emissions. Cluster 4, in yellow, deals with energy and efficiency, featuring terms like flyash, co-incineration, and fuel. The overlaps between these clusters indicate interconnected themes, such as the intersection of waste and energy in Cluster 3 and Cluster 4, and the relationship between alternative fuels and combustion in Cluster 2 and Cluster 3.Illustration of a keyword co-occurrence map. Source: Authors' own work