3D printing of soft EMG sensing structures enables the creation of personalized sensing structures that can be potentially integrated in prosthetic, assistive and other devices. We developed and characterized flexible carbon-black doped TPU-based sEMG sensing structures. The structures are directly 3D-printed without the need for an additional post-processing step using a low-cost, consumer grade multi-material FDM printer. A comparison between the gold standard Ag/AgCl gel electrodes and the 3D-printed EMG electrodes with a comparable contact area shows that there is no significant difference in the EMG signals’ amplitude. The sensors are capable of distinguishing a variable level of muscle activity of the biceps brachii. Furthermore, as a proof of principle, sEMG data of a 3D-printed 8-electrode band are analyzed using a patten recognition algorithm to recognize hand gestures. This work shows that 3D-printed sEMG electrodes have great potential in practical applications.

The rapid technological evolution verified over the past years strongly relies on the operation of stationary and mobile electric and electronic equipments. Further, the increasing energy consumption due to the incessant growth of technological devices results in the excessive use of fossil fuels. [1,2] As such, there is a growing need to produce clean and environmental friendly energy coming from renewable energy sources, [3] respecting the principle of sustainable development, stated in the Brundtland report. [4] Electrochemical lithium-ion batteries represent an advantageous technology for this purpose, due to the high volumetric (Wh L À1) and gravimetric (Wh g À1) energy densities when compared with other conventional electrochemical batteries. [5,6] In addition, they also show several attractive features, such as the lack of memory effect, low self-discharge, high number of charge and discharge cycles, and high energy efficiency in the process of energy conversion. [7,8] It is also important to note that the global market for lithium-ion batteries is growing, expecting that the global value will reach US$77.42 billion in 2024. [9] Lithium-ion batteries are suitable for the integration in portable devices (smartphones, laptops, and tablets) [10] and smart sensors/actuators, very relevant in the "Internet of Things" (IoT), [11] contributing to the rapid implementation of the concepts of smart home, smart city, and point-of-care biomedical devices. [12,13] It also

Low concentrations standards spectrometric analysis using the NITON spectrometer require the LOD and LOQ to be determined from the analytical method along with identification of the sample matrix. The LOD (the smallest quantity of analyte that can be detected but not necessarily quantified) and LOQ (the smallest quantity of analyte that can be measured with acceptable accuracy) must be determined for each individual matrix because the energy dispersive X-ray fluorescence (EDXRF) method used by NITON spectrometer is strongly influenced by the matrix effect. This study determined LODs and LOQs for steel alloy samples using certified reference materials with low analyte concentration and compared the calculated LODs and LOQs to those specified by the manufacturer using a two-way ANOVA analysis for each chemical element.