Purpose Regardless of the materials used, additive manufacturing (AM) is one of the most popular emerging fabrication processes used for creating complex and intricate structural components. This study aims to investigate the effects of process parameters – namely, nozzle diameter, layer thickness and infill density on microstructure as well as the mechanical properties of 17–4 PH stainless steel specimens fabricated via material extrusion AM. Design/methodology/approach The experimental approach investigates the effects of printing parameters, including nozzle diameter, layer thickness and infill density, on surface roughness, physical and mechanical properties of the printed specimens. The tests were triplicated to ensure reproducibility of the experimental results. Findings The highest ultimate tensile strength, 795.26 MPa, was obtained on specimen that was fabricated with a 0.4 mm nozzle diameter, 0.14 mm layer thickness and 30% infill density. Furthermore, a 0.4 mm nozzle diameter also provided slightly better ductility. This came at the expense of surface finishing, as a 0.25 mm nozzle diameter exhibited better surface finishing over a 0.4 mm nozzle diameter. Infill density was shown to slightly influence the tensile properties, whereas layer thickness showed a significant effect on surface roughness. By contrast, hardness and ductility were independent of nozzle diameter, layer thickness and infill density. Originality/value This paper presents a comprehensive analysis relating to various input printing parameters on microstructural, physical and mechanical properties of additively manufactured 17–4 PH stainless steel to improve the printability and processability via AM.

Autopsy findings in intravenous drug addicts are quite variable and may involve a number of organ systems. Reports of the macroscopic identification at autopsy of components of tablets that have been crushed and injected are, however, exceedingly rare. The case of 34-year-old man who died of zolpidem toxicity on a background of pulmonary hypertension attributed to intravenous injections of crushed tablets is described. A very unusual finding was very fine white stippling on the cut surfaces of both the liver and spleen which was shown on energy-dispersive x-ray spectroscopy (EDS) to be titanium dioxide most likely from the coating of the zolpidem tablets.This case is significant in demonstrating titanium dioxide accumulation within organs at both macroscopic and microscopic levels, with confirmation of exposure by EDS analysis. The clinical significance of exposure to such high levels of titanium dioxide is unclear.

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