On the Microstructure, Strength, Fracture, and Tribological Properties of Iron-Based MMCs with Addition of Mixed Carbide Nanoparticulates.

In this paper, the features of the strength, fractures, and tribological behavior of metal-matrix composites based on the FeGr1 material are discussed. To improve the material properties, a mixture of SiC, Al2O3 and C nanoparticulates have been added to an iron-based matrix. The simplex lattice design method and hardness, compression, and bending tests were used to determine the mechanical properties. Scanning electron microscopy was applied for fracture features analysis. Different fracture types, mainly trans-crystalline quasi-brittle and brittle fracture or inter-granular fracture and microcracks were registered for the composites tested. Depending on the type and amount of ceramic additives, significant changes in strength, as well as in the fracture features of the metal-matrix composites (MMCs), were observed. Based on tribological tests, changes in the momentary coefficients of friction, temperature of the friction surface, and wear rate of the composites with nanoparticulates were described. An analysis of the worn surface morphology revealed changes in the wear process depending on the MMC composition. It was shown that the use of hybrid mixed additives based on hard ceramic nanoparticulates improved both strength and tribological properties of composites.

A case of ultrasound diagnosis of retroperitoneal lesion caused by unnoticed foreign body ingestion.

We report the case of a 52-year-old patient who was initially admitted to the District Hospital's Surgery Ward with strong abdominal pain. The patient's medical history before the hospitalization was unremarkable. The man did not recall any worrisome situations before the onset of pain. During the hospital stay, he underwent an ultrasound scan, computed tomography and magnetic resonance imaging evaluations, and laboratory tests suggesting that paraduodenal abscess or gastrointestinal stromal tumor should be considered. The patient was referred to the provincial hospital in order to undergo endoscopic ultrasonography. This was when a retroperitoneal foreign body, a toothpick, was found and removed.We report the case of a 52-year-old patient who was initially admitted to the District Hospital's Surgery Ward with strong abdominal pain. The patient's medical history before the hospitalization was unremarkable. The man did not recall any worrisome situations before the onset of pain. During the hospital stay, he underwent an ultrasound scan, computed tomography and magnetic resonance imaging evaluations, and laboratory tests suggesting that paraduodenal abscess or gastrointestinal stromal tumor should be considered. The patient was referred to the provincial hospital in order to undergo endoscopic ultrasonography. This was when a retroperitoneal foreign body, a toothpick, was found and removed.