# Additive Manufacturing and Chemical Engineering: Looking for Synergies from a Bibliometric Study
## 3 Results and Discussion
### Bibliometric Performance Analysis
#### 3.1.3 Distribution of Output in Subject Categories and Journals  
Given the scope of this research, which is limited to the field of Chemical Engineering, only documents that are classified into this subject area in Scopus have been considered. As illustrated in Table 7, this approach has resulted in the inclusion of all the documents within this area. It should be noted, however, that this category is not exclusive, as a single document can belong to multiple subject areas. This results in the total sum of individual percentages exceeding 100%. The thematic areas most closely related to or intersecting with chemical engineering are engineering, with 2119 documents (56.3% contribution), and materials science, with 1839 documents (48.9% contribution). These areas reflected the interactions and synergies among different branches of engineering oriented towards different applications and the relevance of the materials employed in additive manufacturing. Additionally, two fundamental sciences, chemistry and physics, were represented in fourth and fifth position with 938 documents (24.9%) and 861 documents (22.9%), respectively. These areas highlighted the significance of theoretical and experimental foundations for advancement and innovation in additive manufacturing. The field of chemistry providesthe means to create new materials with specific properties, while the discipline of physics offers insights into the process dynamics and material behaviors for optimizing manufacturing techniques. Computer Science constituted the sixth subject area, accounting for over 15% of the total, with 592 documents. The developments in simulation software and computational modeling have facilitated precise control over additive manufacturing processes and material properties. Moreover, the development of new algorithms is necessary to optimize design complexity and enhance the efficient employment of materials. The multiple contributions from different knowledge areas substantiate the multidisciplinary nature of additive manufacturing and the necessity of adapting it to each specific application [46]. The number of documents published in the most frequently utilized sources is presented in Table 8. To assess the relevance of the sources, the corresponding SCImago Journal Ranking indexes (SJR), Impact Factors (IFs), and Journal Citation Indicators (JCIs) of the top 14 sources, which are the only ones that published at least 40 articles, were included. The Journal Citation Indicator (JCI) is defined as the average Category Normalized Citation Impact (CNCI) of citable items (articles and reviews) published by a journal over a recent three-year period [47]. The average JCI in a category is 1.0. Journals with a JCI of 1.35 have a 35% greater citation impact than the mean for that category. This index provides a more precise understanding of a journal's absolute relevance, whereas the SJR and IF indexes offer insights within a relative framework that facilitates direct comparisons between different journals. The two leading sources, _Lecture Notes in Mechanical Engineering_ and _Applied Sciences_, accounted for over 10% of the total scientific production, with 447 and 402 documents, respectively, representing 11.89% and 10.69% contributions. \begin{table}
\begin{tabular}{l l l} \hline
**Subject** & **Publications** & **Contribution (\%)** \\ \hline Chemical Engineering & 3761 & 100.00 \\ Engineering & 2119 & 56.34 \\ Materials Science & 1839 & 48.90 \\ Chemistry & 938 & 24.94 \\ Physics and Astronomy & 861 & 22.89 \\ Computer Science & 592 & 15.74 \\ Biochemistry, Genetics, and Molecular Biology & 544 & 14.46 \\ Energy & 240 & 6.38 \\ Environmental Science & 198 & 5.26 \\ Medicine & 145 & 3.86 \\ \hline \end{tabular}
\end{table} 
Table 7: The top 10 most popular subject categories (at least 140 documents).