## 3 Augmented Reality in Industry
### AR in the Chemical Industry
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Reference** & **Applications** & **Area** \\ \hline
[30] & Corrective maintenance in chemical industries using augmented reality and digital twin. & Operation and Maintenance \\ \hline
[31] & Virtual reality (VR) and AR taxonomy in education. & Education \\ \hline
[32] & The study aims to develop effective cooperative coaching and learning systems that expedite the acquisition of fundamental construction skills. & Education \\ \hline
[33] & The study examines the use of AR in a practicum for training apprentices in the chemical industry. & Education \\ \hline
[34] & The study investigates the general approach to the concept of Industry 4.0 and levels of adoption of the basic Industry 4.0 technologies in manufacturing firms across Turkey. & Industry 4.0–Technology \\ \hline
[35] & To explore telescopic multi-resolution (TMR) in AR visualization, allowing for consistent approximation of interactions between microscopic and macroscopic systems through real-world measurements, interdisciplinary principles, and multi-scale visualizations. & Visualization–Technology \\ \hline
[36] & To identify the impact of Industry 4.0 technology on the international posting of workers considering the COVID-19 pandemic on the German chemical industry example. & Industry 4.0–Technology \\ \hline
[37] & Systematic literature review to identify immersive technologies applications published in the past twenty years and aimed to enhance the training and learning of operators in the process industry. & SLR for Education \\ \hline
[38] & To showcase how the American Fuel \& Petrochemical Manufacturers (AFPM) and its members address competency training challenges and bridge the knowledge gap between generations of employees by developing a digital library of immersive learning tools, including VR and AR simulations, for broad industry use. & Education \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Chemical industry applications. Figure 10: Most frequent words (keyword plus). In this sense, the studies above in the chemical and augmented reality area cover various topics, including maintenance, education, Industry 4.0, and testing, with the education domain being the most utilized. One area of focus is education, with studies exploring using AR and virtual reality (VR) technologies to enhance learning experiences and build fundamental skills in construction, apprentice training in the chemical industry, and operator training. In the process industry, these studies emphasize the potential of immersive technologies to facilitate knowledge acquisition and improve training outcomes. Another significant area of focus is Industry 4.0, with studies investigating its adoption in manufacturing companies. This includes examining levels of adoption of Industry 4.0 technologies and their effects on international labor markets, such as posting workers in the chemical industry. The objective is understanding the implications and challenges of integrating advanced technologies in industrial environments. In the context of Industry 4.0, AR can be applied in the chemical industry to transform traditional practices by enabling more innovative, safer, and more efficient operations. This integration increases productivity and safety, which are particularly critical in the chemical sector. Therefore, some of the key applications and benefits of AR in the chemical industry within the framework of Industry 4.0 are detailed in Table 2.  
Additionally, studies are exploring the use of augmented reality in maintenance operations, specifically corrective maintenance in chemical industries. Augmented reality systems and digital twin technology are utilized to improve maintenance processes by providing real-time guidance and visualization to technicians for efficient equipment inspection and repair. Furthermore, the application of immersive technologies in additive manufacturing is explored, particularly in testing portable chemical, biological, radiological, and nuclear (CBRN) recognition products.