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Dissimilar friction stir welding joints are widely employed in the industrial field due to the excellent microstructural and mechanical properties of the resulting joints. Nevertheless, to further enhance the weld properties, the addition of reinforcement particles on the joint-line during the process has been proven effective for increasing its mechanical performance. In the present investigation, the microstructure and the impact behaviour of FSWed joints between AA2024-T351 and AA7075-T651 aluminium plates were investigated, considering the effect of different process parameters selected through a full factorial 2k design of experiments: both the rotational and translational speed of the tool, as well as the addition of Al2O3-SiC microparticles, were considered as input parameters. Unnotched 10 x 5 x 55 mm impact specimens were tested through an instrumented 50 J Charpy pendulum: total impact energy, the two complementary initiation and propagation energies as well as the peak force were correlated to the adopted process parameters. From the performed analyses, it was found that joints with reinforcing particles are prone to form wormhole defects across the stir zone that not only affect the microstructural development, but also the impact behaviour since they require less energy at break in comparison with joints fabricated without particles addition.

This chapter reflects on the possibilities and challenges of a course entitled “Residents in the City: Latinx Spaces and Human Mobility in the Quad Cities.” The course was conceived as a combination of critical theory on culture, human mobility and space with extensive community engagement in the Floreciente neighborhood in Moline (Quad Cities, Illinois), an area going through increasing gentrification and traversed by migration histories, with Mexican being the most current. The chapter illustrates how an urban cultural studies framework serves to articulate theory and praxis, the material and the imaginary, ultimately undoing broad definitions of “migration” and the “immigrant” and paving the way for a thicker understanding of how those who reside in a city, ultimately make it.

The polyurethane foam (PUF) allowed the growth of Gluconacetobacter xylinus for prompt production of bacterial cellulose (BC) due to high water storage capacity that let high water activity, as well as diffusion of oxygen through the PUF pores. PUF was studied in two sizes cut (0.13 cm3) and minced (0.08 cm3). Additionally, the study assessed the level of inoculum on the growth and the formation of BC. The highest yield of BC was 2.46 g L-1 of cellulose achieved with cut foam and 15% inoculum at 96 h. Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and solid state 13C cross polarization and magic angle spinning nuclear magnetic resonance (CP/MAS NMR) analyses evidence crystalline structure type I for the produced microbial cellulose. According to scanning electron microscopy (SEM) analysis, the bacteria synthesized the biopolymer as a biofilm adhered to the solid support; thereby BC displays a honeycomb geometry.