Open Access

For medical polymers, their surface condition is an important factor for their biocompatibility in potential applications. The occurrence of antioxidant separation, in form of additive blooming onto the material surface causes changes in the chemical composition, topography, stability and could influence the bioactivity of the medical devices. In this study, the separation of Irganox antioxidant occurring after the spin coating of polyurethane into thin films under 1 µm thickness was examined. The phenomenon was observed with different polymers from the Pellethane series. The extent of the blooming and its aftereffects were evaluated using scanning electron microscopy (SEM), atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS) and Raman microscopy. The compatibility of Irganox with the polymers was compared on the basis of the Hansen solubility parameter (HSP) concept. Additionally, Raman imaging in combination with basis analysis was established as a viable and fast method for polymer-additive distinction. The surface coverage of the bloomed areas increased with film thickness, and with it, its impact onto the surface chemistry and topography of the thin films. Simple protein coating tests indicated that the bloomed areas slightly impact the ability of fibronectin to form protein netting structures on the surface.

The efficient and safe movement of goods and people require reliable railway systems. Quality assurance of manufactured and assembled systems and correct maintenance of such systems are required to keep rolling stock in good operational condition. Quality assurance and maintenance in the railway industry can be costly and time-consuming, but the expansive growth of data due to smart sensors and monitoring technologies makes it possible to leverage the potential of machine learning to reduce cost and labour. Improved reliability and safety, and reduced costs are benefits that the use of “Big Data” and machine learning techniques can realise. However, despite these potential benefits for manufacturers, rail operators, and passengers, the rail industry is still labelled for its lack of innovation, while in most other industries, data is regarded as a strategic asset for competitive advantage. This paper demonstrates how machine learning and data analysis can be used to benefit railway industry manufacturers and operators when applied to rolling stock data. It also illustrates the lost opportunity in the rail industry for not applying data-driven solutions to their full potential. The paper also discusses the current applications of machine learning in the railway industry and provides the requirements for the implementation of machine learning techniques. Machine learning is applied to pantograph data of a South African railway operator's rolling stock. Classification – a machine learning technique – is used to identify and categorise events within the dataset to discover whether pantograph bounce occurs due to faulty sensors, faulty pantographs, or defective infrastructure. In this paper it is demonstrated how machine learning can benefit rail manufacturers and operators to improve manufacturing and assembly processes, as well as maintenance practices. It is concluded that railways should treat data similarly to other railway assets, with suitable management and governance practices.

In increasingly complex production environments, tremendous efforts are being made to optimize the efficiency of a production system. An important efficiency factor is industrial maintenance, both influencing the cost and securing the technical availability of machines and components. Maintenance managers are required to deliver the necessary availability of the production system while minimizing the resources needed to do so. To make this possible, a method to evaluate the dependency between the technical availability of an entire production system and maintenance resources is necessary. This paper presents a systematic literature review of such methods is presented. In order to assess the methods proposed in the literature, first, requirements are developed, including a necessary focus on maintenance strategies within these methods. Including maintenance strategies is necessary since they provide the foundation for both the availability of a component and the maintenance resources needed. In total, 13 requirements are developed, and 21 different methods are evaluated. Only one of the proposed methods addresses all requirements, with others lacking possible combinations of maintenance strategies and the resulting influences on the production system.

To strive for a sustainable production, maintenance has to evaluate possible machine failure consequences not just economically but also holistically. Approaches such as the ultra-efficiency factory consider energy, material, human/staff, emission, and organization as optimization dimensions. These ultra-efficiency dimensions can be considered for analyzing not only the respective machine failure but also the effects on the entire production system holistically. This paper presents an easy to use method, based on a questionnaire, for assessing the failure consequences of a machine malfunction in a production system considering the ultra-efficiency dimensions. The method was validated in a battery production.

The increasing complexity and need for availability of automated guided vehicles (AGVs) pose challenges to companies, leading to a focus on new maintenance strategies. In this paper, a smart maintenance architecture based on a digital twin is presented to optimize the technical and economic effectiveness of AGV maintenance activities. To realize this, a literature review was conducted to identify the necessary requirements for Smart Maintenance and Digital Twins. The identified requirements were combined into modules and then integrated into an architecture. The architecture was evaluated on a real AGV on the battery as one of the critical components.