# Additive Manufacturing and Chemical Engineering: Looking for Synergies from a Bibliometric Study
## 3 Results and Discussion  
### Bibliometric Performance Analysis  
#### 3.1.1 Publication Year, Language of Publications, and Document Type  
The graphical representations in Figure 3 illustrate the evolution of the annual scientific output tracked in the Scopus database and the cumulative number of documents from 2002 (the year of the first identified document) to 2022. The pioneering work in the first decade of the 21 st century consisted of only six documents published before 2010, but different additive manufacturing technologies were covered, such as stereolithography for manufacturing injection models [19], laser powder deposition [20], or precision droplet manufacturing [21]. The analysis of the graphs in Figure 3 shows that the scientific production on the topic has experienced accelerated growth in recent years, especially since 2015. The number of publications has increased from 1 in 2002 to 953 in 2022. This increase can be attributed to technological advances and the increased demand for additive manufacturing, which has facilitated the development of new materials, processes, and applications, including contributions from chemical engineering and applications in this field [22]. The most productive years, or those with the highest number of publications on the topic, were the last three: 2020, 2021, and 2022. During these years, 667, 832, and 953 documents were published, respectively, representing 72% of the total. These years coincided with the context of the COVID-19 pandemic, which stimulated research and innovation in materials and processes to address the health and economic crisis [23]. On the other hand, some years in the 2000s appeared without any production, such as 2003, 2004, 2006, and 2009. This decade corresponded to the beginning of the diffusion of additive manufacturing as an \begin{table}
\begin{tabular}{l l} \hline \hline
**Parameter** & **Value** \\ \hline Unit of analysis & Words (author’s words, source’s words, and added words) \\ Frequency reduction & 12 \\ Kind of matrix & Co-occurrence \\ Edge value reduction & 4 \\ Normalization measure & Equivalence index \\ Clustering algorithm & Simple centers \\ Maximum network size & 11 \\ Minimum network size & 7 \\ Evolution map measure & Jaccard’s index \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Parameter configuration used for the analysis by SciMAT. emerging and promising technology for chemical engineering and other fields, including its standardization [10]. Figure 3: Annual (**a**) and accumulated (**b**) publication output. The line in the graph of the accumulated publication output represents the exponential fitting. The observed evolution of scientific production on this topic followed an exponential trend, indicating that the rate of growth has been variable and has progressively increased over time. The exponential regression yielded an equation of the form y = 0.345-e\({}^{0.445\mathrm{x}}\), where \"y\" represents the accumulated number of publications and \"x\" represents the year, with the value equal to one for the year 2002. The corresponding R\({}^{2}\) value was 0.986, indicating a strong correlation between the observed and estimated data by the equation. Consequently, the projected trajectory of scientific production on this topic, based on the exponential regression, suggests that the trend is expected to persist and potentially accelerate in the coming years, presenting both challenges and opportunities for research in this field. A review of Table 3, which outlines the languages utilized in the selected documents, indicates that English is the predominant language, accounting for 98.1% of the total documents (3691). This suggests that English serves as the universal language or international standard for scientific communication, enabling the dissemination of the research findings to a global audience and facilitating collaboration among researchers from different countries and regions [24]. The next most utilized language is Chinese, with 38 documents, which accounts for 1.0% of the total.