With the current technological transformation in the automotive industry, autonomous vehicles are getting closer to the Society of Automative Engineers (SAE) automation level 5. This level corresponds to the full vehicle automation, where the driving system autonomously monitors and navigates the environment. With SAE-level 5, the concept of a Shared Autonomous Vehicle (SAV) will soon become a reality and mainstream. The main purpose of an SAV is to allow unrelated passengers to share an autonomous vehicle without a driver/moderator inside the shared space. However, to ensure their safety and well-being until they reach their final destination, active monitoring of all passengers is required. In this context, this article presents a microphone-based sensor system that is able to localize sound events inside an SAV. The solution is composed of a Micro-Electro-Mechanical System (MEMS) microphone array with a circular geometry connected to an embedded processing platform that resorts to Field-Programmable Gate Array (FPGA) technology to successfully process in the hardware the sound localization algorithms.

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The growing demand for polymeric materials makes them significant in both industry and the environment, and the task of making them sustainable is becoming increasingly challenging. Cellulose presents an opportunity to minimize the effect of non-degradable materials. Cellulose nanofiber (CNF) is part of a class of cellulose fibers with superior performance due to its high strength and stiffness combined with low weight and biodegradability. This work aimed to produce composites using Low Density Polyethylene (LDPE) as matrix and CNF from Pinus sp. (Pinus) and Eucalyptus sp. (Eucalyptus) as reinforcement. The CNF were obtained by mechanical defibrillation of the cellulose, subsequently the water was removed by centrifugation to then produce a master with CNF and LDPE using a thermokinetic homogenizer. The master was milled and blended with LDPE to obtain booster concentrations of 1, 2 and 3 percent by weight (wt. %). To characterize the composite, tensile and flexural tests, thermal and rheological analysis were performed. As a result, an increase of between 3 and 4% in the crystallinity of the composite was evidenced with the addition of Pinus CNF and a reduction of 2 to 3% in the crystallinity index with the addition of Eucalyptus CNF. Thermal stability increased for all compositions. For mechanical properties, increasing the CNF content increased the stiffness and tensile strength. In general, it was found that the process is an effective alternative to produce composites of LDPE with cellulose nanofibers.